Remove orphaned comments and tidy ScriptExpr/ScriptCmd enums

Co-Authored-By: Claude Opus 4.8 <[email protected]>

.github/ISSUE_TEMPLATE/bug_report.md

@@ -1,10 +0,0 @@
----
-name: Bug report
-about: Create a report to help us improve
-title: ''
-labels: ''
-assignees: ''
-
----
-
-Delete this message and describe the bug here. Note that we only fix bugs in the most recent release of mold, so please make sure that you are using the most recent version.

.github/workflows/build-all.yml

@@ -0,0 +1,93 @@
+name: Build all tarballs
+
+on:
+  schedule:
+    - cron: '0 0 * * *'
+  workflow_dispatch:
+
+jobs:
+  check-changes:
+    runs-on: ubuntu-24.04
+    outputs:
+      has_changes: ${{ github.event_name == 'workflow_dispatch' || steps.check.outputs.has_changes }}
+    steps:
+    - name: Check for new commits since last successful run
+      id: check
+      env:
+        GH_TOKEN: ${{ github.token }}
+      run: |
+        last=$(gh run list -R ${{ github.repository }} -w build-all.yml -b main -s success -L1 --json createdAt -q '.[0].createdAt')
+        if [ -z "$last" ] || [ "$last" = "null" ] || [ "$(gh api repos/${{ github.repository }}/commits?sha=main\&since=$last\&per_page=1 | jq length)" -gt 0 ]; then
+          echo "has_changes=true" >> "$GITHUB_OUTPUT"
+        fi
+
+  build-linux:
+    needs: check-changes
+    if: needs.check-changes.outputs.has_changes == 'true'
+    strategy:
+      matrix:
+        include:
+          - { target: x86_64,      os: ubuntu-24.04 }
+          - { target: aarch64,     os: ubuntu-24.04-arm }
+          - { target: arm,         os: ubuntu-24.04-arm }
+          - { target: riscv64,     os: ubuntu-24.04 }
+          - { target: ppc64le,     os: ubuntu-24.04 }
+          - { target: s390x,       os: ubuntu-24.04 }
+          - { target: loongarch64, os: ubuntu-24.04 }
+
+    runs-on: ${{ matrix.os }}
+
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+    - name: Checkout Repository
+      uses: actions/checkout@v6
+
+    - name: Install Podman
+      run: sudo apt-get update && sudo apt-get install -y podman qemu-user-static
+
+    - name: Login to GitHub Container Registry
+      uses: redhat-actions/podman-login@v1
+      with:
+        registry: ghcr.io
+        username: ${{ github.repository_owner }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+
+    - name: Build a tarball
+      run: ./dist.sh ${{ matrix.target }}
+
+    - name: Upload artifact
+      uses: actions/upload-artifact@v7
+      with:
+        name: ${{ matrix.target }}
+        path: dist/mold-*.tar.gz
+        compression-level: 0
+
+  build-windows:
+    needs: check-changes
+    if: needs.check-changes.outputs.has_changes == 'true'
+    runs-on: windows-latest
+    steps:
+    - name: Checkout Repository
+      uses: actions/checkout@v6
+
+    - name: Build and Archive
+      shell: pwsh
+      run: |
+        mkdir build
+        cd build
+        cmake -T clangcl ..
+        cmake --build . --config Release -j $Env:NUMBER_OF_PROCESSORS
+        cmake --install . --config Release --prefix ../mold-install
+        cd ..
+        New-Item -ItemType Directory -Force dist | Out-Null
+        $version = $Env:TAG -replace '^v', ''
+        Compress-Archive -Path mold-install\* -DestinationPath dist\mold-$version-windows-x86_64.zip
+
+    - name: Upload artifact
+      uses: actions/upload-artifact@v7
+      with:
+        name: win-x86_64
+        path: dist/mold-*.*

.github/workflows/build-native.yml

@@ -0,0 +1,44 @@
+name: Build native tarballs
+
+on:
+  push:
+  workflow_dispatch:
+
+jobs:
+  build-tarballs:
+    strategy:
+      matrix:
+        include:
+          - { target: x86_64,  os: ubuntu-24.04 }
+          - { target: aarch64, os: ubuntu-24.04-arm }
+          - { target: arm,     os: ubuntu-24.04-arm }
+
+    runs-on: ${{ matrix.os }}
+
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+    - name: Checkout Repository
+      uses: actions/checkout@v6
+
+    - name: Install Podman
+      run: sudo apt-get update && sudo apt-get install -y podman qemu-user-static
+
+    - name: Login to GitHub Container Registry
+      uses: redhat-actions/podman-login@v1
+      with:
+        registry: ghcr.io
+        username: ${{ github.repository_owner }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+
+    - name: Build a tarball
+      run: ./dist.sh ${{ matrix.target }}
+
+    - name: Upload artifact
+      uses: actions/upload-artifact@v7
+      with:
+        name: ${{ matrix.target }}
+        path: dist/mold-*.tar.gz
+        compression-level: 0

.github/workflows/ci.yml

@@ -1,114 +1,172 @@
 name: CI
 on:
   push:
-    branches: [ main ]
   pull_request:
-    branches: [ main ]
 env:
   UBSAN_OPTIONS: print_stacktrace=1:halt_on_error=1
 jobs:
-  build-clang:
+  build-asan-tsan:
     strategy:
       matrix:
         target:
-        # Disable PCH for the default configuration. This prevents relying on implicit includes.
-        - '-DCMAKE_DISABLE_PRECOMPILE_HEADERS=On'
+        - ''
         - '-DMOLD_USE_ASAN=On'
         - '-DMOLD_USE_TSAN=On'
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-24.04
+    timeout-minutes: 60
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v6
     - uses: rui314/setup-mold@staging
-    - name: install-build-deps
-      run: sudo ./install-build-deps.sh update
-    - name: ccache
-      uses: hendrikmuhs/ccache-action@v1
-    - name: build and test
+    - run: sudo ./install-build-deps.sh
+    - name: build
       run: |
-        echo "/usr/lib/ccache:/usr/local/opt/ccache/libexec" >> $GITHUB_PATH
+        sudo apt-get install -y clang-18 clang gcc-multilib gdb dwarfdump zstd
         mkdir build
         cd build
-        cmake -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ ${{ matrix.target }} ..
+        cmake -DCMAKE_BUILD_TYPE=Debug -DCMAKE_C_COMPILER=clang-18 -DCMAKE_CXX_COMPILER=clang++-18 ${{ matrix.target }} ..
         cmake --build . -j$(nproc)
-        ctest . -j$(nproc)
-
-  build-gcc:
-    runs-on: ubuntu-20.04
-    container: gcc:11.1.0
-    steps:
-    - uses: actions/checkout@v3
-    - name: install-build-deps
-      run: |
-        # Install cross toolchains
-        dpkg --add-architecture i386
-        ./install-build-deps.sh update
-        apt-get install -y sudo qemu-user gdb zstd dwarfdump {gcc,g++}-10-{i686,aarch64,riscv64,powerpc,powerpc64,powerpc64le,s390x,sparc64,m68k,sh4,alpha}-linux-gnu {gcc,g++}-10-arm-linux-gnueabihf
-
-        for i in i686 aarch64 riscv64 powerpc powerpc64 powerpc64le s390x sparc64 m68k sh4 alpha; do
-          ln -sf /usr/bin/$i-linux-gnu-gcc-10 /usr/bin/$i-linux-gnu-gcc
-          ln -sf /usr/bin/$i-linux-gnu-g++-10 /usr/bin/$i-linux-gnu-g++
-        done
-
-        ln -sf /usr/bin/arm-linux-gnueabihf-gcc-10 /usr/bin/arm-linux-gnueabihf-gcc
-        ln -sf /usr/bin/arm-linux-gnueabihf-g++-10 /usr/bin/arm-linux-gnueabihf-g++
-
-        # Install a RV32 toolchain from third party since it's not available
-        # as an Ubuntu package.
-        mkdir /usr/local/rv32
-        wget -O- -q https://github.com/riscv-collab/riscv-gnu-toolchain/releases/download/2022.08.26/riscv32-glibc-ubuntu-20.04-nightly-2022.08.26-nightly.tar.gz | tar -C /usr/local/rv32 --strip-components=1 -xzf -
-
-        ln -sf /usr/local/rv32/sysroot /usr/riscv32-linux-gnu
-        ln -sf /usr/local/rv32/bin/riscv32-unknown-linux-gnu-objdump /usr/bin/riscv32-linux-gnu-objdump
-        echo '/usr/local/rv32/bin/riscv32-unknown-linux-gnu-gcc -L/usr/riscv32-linux-gnu "$@"' > /usr/bin/riscv32-linux-gnu-gcc
-        echo '/usr/local/rv32/bin/riscv32-unknown-linux-gnu-g++ -L/usr/riscv32-linux-gnu "$@"' > /usr/bin/riscv32-linux-gnu-g++
-        chmod 755 /usr/bin/riscv32-linux-gnu-gcc /usr/bin/riscv32-linux-gnu-g++
-      shell: bash
-    - name: ccache
-      uses: hendrikmuhs/ccache-action@v1
-    - name: build and test
-      run: |
-        echo "/usr/lib/ccache:/usr/local/opt/ccache/libexec" >> $GITHUB_PATH
-        mkdir build
-        cd build
-        cmake -DMOLD_ENABLE_QEMU_TESTS=On -DMOLD_ENABLE_QEMU_TESTS_RV32=On ..
-        cmake --build . -j$(nproc)
-        ctest . -j$(nproc)
+    - run: cd build; ctest --output-on-failure -j$(nproc)
     - name: archive test results
-      uses: actions/upload-artifact@v3
-      if: always()
+      uses: actions/upload-artifact@v7
+      if: failure()
       with:
-        name: test-results
+        name: test-results-clang
         path: |
-          build/out
-          build/Testing
+          build
+          !build/CMakeFiles
 
-  build-macos:
-    runs-on: macos-11
+  build-msan:
+    runs-on: ubuntu-24.04
+    timeout-minutes: 60
+    steps:
+    - uses: actions/checkout@v6
+    - uses: redhat-actions/podman-login@v1
+      with:
+        registry: ghcr.io
+        username: ${{ github.repository_owner }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+    - run: .github/workflows/run-msan.sh
+
+  build-multi-archs:
+    runs-on: ubuntu-24.04
+    timeout-minutes: 60
+    steps:
+    - uses: actions/checkout@v6
+    - name: install-build-deps
+      run: |
+        sudo ./install-build-deps.sh
+        sudo ./install-cross-tools.sh
+        sudo .github/workflows/install-extras.sh
+    - name: build
+      run: |
+        mkdir build
+        cd build
+        cmake ..
+        cmake --build . -j$(nproc)
+    - run: cd build; ctest --output-on-failure -j$(nproc)
+    - name: archive test results
+      uses: actions/upload-artifact@v7
+      if: failure()
+      with:
+        name: test-results-multi-archs
+        path: |
+          build
+          !build/CMakeFiles
+
+  build-distros:
     strategy:
       matrix:
-        target:
-        # Disable PCH for the default configuration. This prevents relying on implicit includes.
-        - '-DCMAKE_DISABLE_PRECOMPILE_HEADERS=On'
-        - '-DMOLD_USE_ASAN=On'
+        distro:
+        - alpine
+        - archlinux
+        - debian:11 # GCC 10 and CMake 3.18 - the minimum supported by mold
+        - fedora
+        - gentoo/stage3
+        - opensuse/tumbleweed
+        - ubuntu:22.04
+        - ubuntu:25.04
+    runs-on: ubuntu-latest
+    timeout-minutes: 60
+    container: ${{ matrix.distro }}
     steps:
-    - uses: actions/checkout@v3
-    - name: ccache
-      uses: hendrikmuhs/ccache-action@v1
-    - name: build and test
+    - uses: actions/checkout@v6
+    - run: ./install-build-deps.sh
+    - name: build
       run: |
-        echo "/usr/lib/ccache:/usr/local/opt/ccache/libexec" >> $GITHUB_PATH
         mkdir build
         cd build
-        cmake ${{ matrix.target }} ..
+        cmake ..
+        cmake --build . -j$(nproc)
+    - run: cd build; ctest --output-on-failure -j$(nproc)
+    - name: sanitize distro name
+      if: failure()
+      id: sanitize
+      run: echo "name=$(echo '${{ matrix.distro }}' | tr '/:' '--')" >> "$GITHUB_OUTPUT"
+    - name: archive test results
+      uses: actions/upload-artifact@v7
+      if: failure()
+      with:
+        name: test-results-${{ steps.sanitize.outputs.name }}
+        path: |
+          build
+          !build/CMakeFiles
+
+  build-macos:
+    runs-on: macos-latest
+    timeout-minutes: 60
+    steps:
+    - uses: actions/checkout@v6
+    - name: build
+      run: |
+        mkdir build
+        cd build
+        cmake ..
         cmake --build . -j$(sysctl -n hw.physicalcpu)
 
   build-windows:
     runs-on: windows-latest
+    timeout-minutes: 60
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v6
     - name: build
       run: |
         mkdir build
         cd build
         cmake -T clangcl ..
         cmake --build . -j $Env:NUMBER_OF_PROCESSORS
+
+  build-msys:
+    runs-on: windows-latest
+    timeout-minutes: 60
+    steps:
+    - uses: actions/checkout@v6
+    - name: Setup MSYS2
+      uses: msys2/setup-msys2@v2
+      with:
+        msystem: UCRT64
+        update: true
+        pacboy: gcc-libs:p libwinpthread-git:p tbb:p zlib:p zstd:p dlfcn:p cc:p cmake:p ninja:p
+    - name: build
+      shell: msys2 {0}
+      run: |
+        mkdir build
+        cd build
+        cmake -GNinja -DMOLD_USE_MIMALLOC=OFF -DMOLD_USE_SYSTEM_TBB=ON ..
+        cmake --build . -j $(nproc)
+
+  build-freebsd:
+    runs-on: ubuntu-latest
+    timeout-minutes: 60
+    steps:
+    - uses: actions/checkout@v6
+    - name: Build and test
+      uses: vmactions/freebsd-vm@v1
+      with:
+        usesh: true
+        run: |
+          ./install-build-deps.sh
+          mkdir build
+          cd build
+          cmake ..
+          cmake --build . -j$(nproc)
+          ctest --output-on-failure -j$(nproc)

.github/workflows/install-extras.sh

@@ -0,0 +1,75 @@
+#!/bin/bash -x
+
+apt-get update
+apt-get install -y wget xz-utils
+
+# Install a 32-bit RISC-V toolchain
+mkdir /rv32
+wget -O- --progress=dot:mega https://github.com/riscv-collab/riscv-gnu-toolchain/releases/download/2025.06.13/riscv32-glibc-ubuntu-24.04-gcc-nightly-2025.06.13-nightly.tar.xz | tar -C /rv32 --strip-components=1 --xz -xf -
+
+ln -sf /rv32/sysroot /usr/riscv32-linux-gnu
+echo '/rv32/bin/riscv32-unknown-linux-gnu-gcc -L/usr/riscv32-linux-gnu "$@"' > /usr/bin/riscv32-linux-gnu-gcc
+echo '/rv32/bin/riscv32-unknown-linux-gnu-g++ -L/usr/riscv32-linux-gnu "$@"' > /usr/bin/riscv32-linux-gnu-g++
+chmod 755 /usr/bin/riscv32-linux-gnu-{gcc,g++}
+
+for i in objdump objcopy strip; do
+  ln -sf /rv32/bin/riscv32-unknown-linux-gnu-$i /usr/bin/riscv32-linux-gnu-$i
+done
+
+# Install a LoongArch toolchain
+mkdir /larch
+wget -O- --progress=dot:mega https://github.com/loongson/build-tools/releases/download/2025.06.06/x86_64-cross-tools-loongarch64-binutils_2.44-gcc_15.1.0-glibc_2.41.tar.xz | tar -C /larch --strip-components=1 --xz -xf -
+
+cp -r /larch/loongarch64-unknown-linux-gnu/lib/* /larch/target/lib64
+ln -sf /larch/target /usr/loongarch64-linux-gnu
+
+for i in gcc g++ objdump objcopy strip; do
+  ln -sf /larch/bin/loongarch64-unknown-linux-gnu-$i /usr/bin/loongarch64-linux-gnu-$i
+done
+
+wget -O /usr/local/bin/qemu-loongarch64 --progress=dot:mega https://github.com/loongson/build-tools/releases/download/2025.06.06/qemu-loongarch64
+chmod 755 /usr/local/bin/qemu-loongarch64
+
+# Install ARM32 big-endian toolchain
+mkdir /armeb
+wget -O- --progress=dot:mega https://toolchains.bootlin.com/downloads/releases/toolchains/armebv7-eabihf/tarballs/armebv7-eabihf--glibc--stable-2024.05-1.tar.xz | tar -C /armeb --strip-components=1 --xz -xf -
+
+ln -sf /armeb/armeb-buildroot-linux-gnueabihf/sysroot /usr/armeb-linux-gnueabihf
+echo '/armeb/bin/armeb-linux-gcc -L/usr/armeb-linux-gnu "$@"' > /usr/bin/armeb-linux-gnueabihf-gcc
+echo '/armeb/bin/armeb-linux-g++ -L/usr/armeb-linux-gnu "$@"' > /usr/bin/armeb-linux-gnueabihf-g++
+chmod 755 /usr/bin/armeb-linux-gnueabihf-{gcc,g++}
+
+for i in objdump objcopy strip; do
+  ln -sf /armeb/bin/armeb-linux-$i /usr/bin/armeb-linux-gnueabihf-$i
+done
+
+# Install ARM64 big-endian toolchain
+mkdir /aarch64be
+wget -O- --progress=dot:mega https://toolchains.bootlin.com/downloads/releases/toolchains/aarch64be/tarballs/aarch64be--glibc--stable-2024.05-1.tar.xz | tar -C /aarch64be --strip-components=1 --xz -xf -
+
+ln -sf /aarch64be/aarch64_be-buildroot-linux-gnu/sysroot /usr/aarch64_be-linux-gnu
+echo '/aarch64be/bin/aarch64_be-linux-gcc -L/usr/aarch64_be-linux-gnu "$@"' > /usr/bin/aarch64_be-linux-gnu-gcc
+echo '/aarch64be/bin/aarch64_be-linux-g++ -L/usr/aarch64_be-linux-gnu "$@"' > /usr/bin/aarch64_be-linux-gnu-g++
+chmod 755 /usr/bin/aarch64_be-linux-gnu-{gcc,g++}
+
+for i in objdump objcopy strip; do
+  ln -sf /aarch64be/bin/aarch64_be-linux-$i /usr/bin/aarch64_be-linux-gnu-$i
+done
+
+# Install SH4 big-endian toolchain
+mkdir /sh4aeb
+wget -O- --progress=dot:mega https://toolchains.bootlin.com/downloads/releases/toolchains/sh-sh4aeb/tarballs/sh-sh4aeb--glibc--stable-2024.05-1.tar.xz | tar -C /sh4aeb --strip-components=1 --xz -xf -
+
+ln -sf /sh4aeb/sh4aeb-buildroot-linux-gnu/sysroot /usr/sh4aeb-linux-gnu
+echo '/sh4aeb/bin/sh4aeb-linux-gcc -L/usr/sh4aeb-linux-gnu "$@"' > /usr/bin/sh4aeb-linux-gnu-gcc
+echo '/sh4aeb/bin/sh4aeb-linux-g++ -L/usr/sh4aeb-linux-gnu "$@"' > /usr/bin/sh4aeb-linux-gnu-g++
+chmod 755 /usr/bin/sh4aeb-linux-gnu-{gcc,g++}
+
+for i in objdump objcopy strip; do
+  ln -sf /sh4aeb/bin/sh4aeb-linux-$i /usr/bin/sh4aeb-linux-gnu-$i
+done
+
+# Install Intel SDE CPU emulator for CET-related tests
+mkdir /sde
+wget -O- --progress=dot:mega https://downloadmirror.intel.com/850782/sde-external-9.53.0-2025-03-16-lin.tar.xz | tar -C /sde --strip-components=1 --xz -xf -
+ln -s /sde/sde64 /usr/bin

.github/workflows/release-assets.yml

@@ -0,0 +1,104 @@
+name: Build & attach tarballs on tag push
+
+on:
+  push:
+    tags: ['v[0-9]*']
+
+permissions:
+  contents: write
+  packages: write
+  id-token: write
+
+env:
+  TAG: ${{ github.ref_name }}
+
+jobs:
+  build-linux:
+    strategy:
+      matrix:
+        include:
+        - { target: x86_64,      os: ubuntu-24.04 }
+        - { target: aarch64,     os: ubuntu-24.04-arm }
+        - { target: arm,         os: ubuntu-24.04-arm }
+        - { target: riscv64,     os: ubuntu-24.04 }
+        - { target: ppc64le,     os: ubuntu-24.04 }
+        - { target: s390x,       os: ubuntu-24.04 }
+        - { target: loongarch64, os: ubuntu-24.04 }
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Install Podman
+      run: sudo apt-get update && sudo apt-get install -y podman qemu-user-static
+
+    - name: Login to GitHub Container Registry
+      uses: redhat-actions/podman-login@v1
+      with:
+        registry: ghcr.io
+        username: ${{ github.repository_owner }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+
+    - run: ./dist.sh ${{ matrix.target }}
+
+    - uses: actions/upload-artifact@v7
+      with:
+        name: ${{ matrix.target }}
+        path: dist/mold-*.tar.gz
+
+  build-windows:
+    runs-on: windows-latest
+    steps:
+    - uses: actions/checkout@v6
+
+    - name: Build and Archive
+      shell: pwsh
+      run: |
+        mkdir build
+        cd build
+        cmake -T clangcl ..
+        cmake --build . --config Release -j $Env:NUMBER_OF_PROCESSORS
+        cmake --install . --config Release --prefix ../mold-install
+        cd ..
+        New-Item -ItemType Directory -Force dist | Out-Null
+        $version = $Env:TAG -replace '^v', ''
+        Compress-Archive -Path mold-install\* -DestinationPath dist\mold-$version-x86_64-windows.zip
+
+    - uses: actions/upload-artifact@v7
+      with:
+        name: win-x86_64
+        path: dist/mold-*.*
+
+  publish:
+    needs: [build-linux, build-windows]
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v6
+
+    - uses: actions/download-artifact@v8
+      with:
+        path: dist
+        pattern: '*'
+        merge-multiple: true
+
+    - name: Ensure release exists (create if missing)
+      env:
+        GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      run: |
+        set -e
+        if gh release view "$TAG" >& /dev/null; then
+          echo "Existing release found for $TAG"
+        else
+          echo "Creating draft release for $TAG"
+          gh release create "$TAG" --draft \
+            --title "$TAG" \
+            --notes "Automated draft – fill the changelog later."
+        fi
+
+    - name: Upload tarballs
+      env:
+        GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      run: |
+        gh release upload "$TAG" dist/* --clobber
+        gh release view "$TAG" --json assets --jq '.assets[].name'

.github/workflows/run-msan.sh

@@ -0,0 +1,37 @@
+#!/bin/bash
+set -e -x
+cd "$(dirname $0)"/../..
+
+if [ "$GITHUB_REPOSITORY" = '' ]; then
+  image=mold-msan
+  image_build="podman build -t $image -"
+else
+  # If this script is running on GitHub Actions, we want to cache
+  # the created container image in GitHub's container repostiory.
+  image=ghcr.io/$GITHUB_REPOSITORY/mold-msan
+  image_build="podman build -t $image --output=type=registry --layers --cache-to $image --cache-from $image -"
+fi
+
+cat <<EOF | $image_build
+FROM mirror.gcr.io/library/ubuntu:24.04
+RUN apt-get update && \
+  apt-get install -y --no-install-recommends build-essential gcc g++ wget ca-certificates make cmake ninja-build python3 clang-20 llvm-20-dev libclang-20-dev libclang-rt-20-dev libtbb-dev mold && \
+  rm -rf /var/lib/apt/lists
+RUN mkdir /llvm && \
+  cd /llvm && \
+  wget -O- --progress=dot:mega https://github.com/llvm/llvm-project/archive/refs/tags/llvmorg-21.1.1.tar.gz | tar xzf - --strip-components=1 && \
+  cmake -S ./runtimes -B build -G Ninja -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_RUNTIMES='libcxx;libcxxabi;libunwind' -DCMAKE_C_COMPILER=clang-20 -DCMAKE_CXX_COMPILER=clang++-20 -DLLVM_USE_SANITIZER=MemoryWithOrigins && \
+  cmake --build build -j\$(nproc) && \
+  cmake --install build --prefix /msan && \
+  rm -rf /llvm
+EOF
+
+# Build mold and run its tests
+podman run -it --rm --pull=never -v "$(pwd):/mold:ro" --security-opt seccomp=unconfined $image bash -c "
+set -e
+mkdir /build
+cd /build
+cmake -GNinja -DCMAKE_BUILD_TYPE=Debug -DCMAKE_C_COMPILER=clang-20 -DCMAKE_CXX_COMPILER=clang++-20 -DMOLD_USE_MSAN=ON -DMOLD_STDLIB_PREFIX=/msan -DMOLD_USE_MIMALLOC=0 -DMOLD_USE_SYSTEM_TBB=1 -DMOLD_USE_MOLD=1 /mold
+cmake --build . -j\$(nproc)
+setarch -R ctest --output-on-failure -j\$(nproc)
+"

.github/workflows/update-manpage.yml

@@ -0,0 +1,33 @@
+name: Update manpage
+
+on:
+  push:
+    paths:
+      - 'docs/mold.md'
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  update-manpage:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Check out repository
+      uses: actions/checkout@v6
+
+    - name: Install ronn
+      run: sudo apt-get update && sudo apt-get install -y ronn
+
+    - name: Generate mold.1 from mold.md
+      run: ronn --roff docs/mold.md
+
+    - name: Configure Git
+      run: |
+        git config --global user.name 'Rui Ueyama'
+        git config --global user.email '[email protected]'
+
+    - name: Commit and push if mold.1 is updated
+      run: |
+        git add docs/mold.1
+        git diff --staged --quiet || (git commit -m "Update mold.1 (automated commit)" && git push)

.gitignore

@@ -3,15 +3,9 @@
 *~
 **/.DS_Store
 .cache
-compile_commands.json
-/mold
-/test/tmp
-options.inc
 core
-ld
-ld64
-ld64.mold
 gentoo
-out
 /mold-*.tar.gz
 /build*
+/mold
+/dist

CMakeLists.txt

@@ -1,31 +1,31 @@
 # You can customize a build by specifying CMake options. An option may be
 # given in the -Dvariable=value form. For a boolean variable, `ON` or `1`
-# means true while `OFF` or `0` means false.
+# means true, while `OFF` or `0` means false.
 #
 # Here are a couple of common cmake options:
 #
 #  -DCMAKE_C_COMPILER=<command-name>
 #
-#   Specifies a C compiler name to use. The default value is `cc`.
+#   Specifies the C compiler name to use. The default value is `cc`.
 #
 #  -DCMAKE_CXX_COMPILER=<command-name>
 #
-#   Specifies a C++ compiler name to use. The default value is `c++`.
+#   Specifies the C++ compiler name to use. The default value is `c++`.
 #
 #  -DCMAKE_INSTALL_PREFIX=<directory>
 #
-#   Specifies an install target directory. The default value is `/usr/local`.
+#   Specifies the install target directory. The default value is `/usr/local`.
 #
 #  -DCMAKE_BUILD_TYPE=[Debug | Release | RelWithDebInfo | MinSizeRel]
 #
-#   Specifies a build type. The default is `Release` which is the right
+#   Specifies the build type. The default is `Release`, which is the right
 #   option unless you are debugging mold.
 #
 # An example of a cmake command line is shown below:
 #
 #   $ cmake -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_CXX_COMPILER=g++-12 ..
 #
-# where `..` refers this directory.
+# where `..` refers to this directory.
 #
 # With cmake, you may run `cmake --install .` instead of `make install` to
 # install build artifacts to system directories. If you want to install
@@ -39,36 +39,64 @@
 # how to build mold. However, as a policy, we do not provide a way to
 # enable/disable any individual mold's feature. In other words, we do not
 # provide options like `--enable-foo` or `--disable-foo`. The motivation
-# behind it is build reproducibility. We want to guarantees that all builds
-# of the mold linker of the same version will have the exactly same set of
+# behind this is build reproducibility. We want to guarantee that all builds
+# of the mold linker of the same version will have the exact same set of
 # features and behave exactly the same.
 
-cmake_minimum_required(VERSION 3.13)
-project(mold VERSION 1.10.0)
+cmake_minimum_required(VERSION 3.14)
+project(mold VERSION 2.41.0)
 
 include(CMakeDependentOption)
+include(CheckSymbolExists)
 include(GNUInstallDirs)
 
+add_executable(mold)
+target_compile_features(mold PRIVATE cxx_std_20)
+
+if(MINGW)
+  target_link_libraries(mold PRIVATE dl)
+else()
+  target_link_libraries(mold PRIVATE ${CMAKE_DL_LIBS})
+endif()
+
 # Build mold itself using mold if -DMOLD_USE_MOLD=ON
 option(MOLD_USE_MOLD "Use mold to build mold" OFF)
 if(MOLD_USE_MOLD)
-  add_link_options(-fuse-ld=mold -Wl,--gdb-index)
-endif()
+  target_link_options(mold PRIVATE -fuse-ld=mold)
 
-add_executable(mold)
-target_compile_features(mold PRIVATE cxx_std_20)
-target_link_libraries(mold PRIVATE ${CMAKE_DL_LIBS})
+  if(CMAKE_BUILD_TYPE MATCHES "Deb")
+    target_link_options(mold PRIVATE -Wl,--gdb-index)
+  endif()
+
+  if(CMAKE_BUILD_TYPE MATCHES "^Rel")
+    target_link_options(mold PRIVATE -Wl,--gc-sections,--icf=safe)
+  endif()
+endif()
 
 if(NOT "${CMAKE_CXX_COMPILER_FRONTEND_VARIANT}" STREQUAL "MSVC")
   target_compile_options(mold PRIVATE
     -fno-exceptions
     -fno-unwind-tables
     -fno-asynchronous-unwind-tables
+    -ffunction-sections
+    -fdata-sections
+    -Wall
+    -Wextra
     -Wno-sign-compare
     -Wno-unused-function
+    -Wno-unused-parameter
+    -Wno-missing-field-initializers
     -ggnu-pubnames)
 endif()
 
+if(CMAKE_BUILD_TYPE STREQUAL "Debug")
+  target_compile_options(mold PRIVATE -D_GLIBCXX_ASSERTIONS)
+endif()
+
+if(CMAKE_SYSTEM_NAME STREQUAL "OpenBSD")
+  set(OPENBSD ON)
+endif()
+
 # Build mold with -flto if -DMOLD_LTO=ON
 option(MOLD_LTO "Build mold with link-time optimization enabled")
 if(MOLD_LTO)
@@ -89,44 +117,76 @@ if(MOLD_USE_TSAN)
   target_link_options(mold PRIVATE -fsanitize=thread)
 endif()
 
-# Statically-link libstdc++ and libcrypto if -DMOLD_MOSTLY_STATIC=ON.
+# Enable MemorySanitizer if -DMOLD_USE_MSAN=ON
+option(MOLD_USE_MSAN "Build mold with MemorySanitizer" OFF)
+if(MOLD_USE_MSAN)
+  set(MOLD_STDLIB_PREFIX /usr CACHE FILEPATH "prefix of instrumented stdlib")
+  target_compile_options(mold PRIVATE
+    -g -Og -fsanitize=memory -fsanitize-memory-track-origins
+    -nostdinc++ -isystem ${MOLD_STDLIB_PREFIX}/include/c++/v1
+    -DENABLE_MSAN_UNPOISON
+  )
+  target_link_options(mold PRIVATE
+    -fsanitize=memory
+    -nostdlib++ -L ${MOLD_STDLIB_PREFIX}/lib -lc++
+    -Wl,-rpath,${MOLD_STDLIB_PREFIX}/lib
+  )
+endif()
+
+# Statically-link libstdc++ if -DMOLD_MOSTLY_STATIC=ON.
 #
 # This option is intended to be used by `./dist.sh` script to create a
 # mold binary that works on various Linux distros. You probably don't
 # need nor want to set this to ON.
-option(MOLD_MOSTLY_STATIC "Statically link libstdc++ and libcrypto" OFF)
+option(MOLD_MOSTLY_STATIC "Statically link libstdc++ and some other libraries" OFF)
 if(MOLD_MOSTLY_STATIC)
   target_link_options(mold PRIVATE -static-libstdc++)
-  target_link_libraries(mold PRIVATE libcrypto.a)
 endif()
 
 # Find zlib. If libz.so is not found, we compile a bundled one and
 # statically-link it to mold.
 find_package(ZLIB QUIET)
-if(ZLIB_FOUND)
+if(ZLIB_FOUND AND NOT MOLD_MOSTLY_STATIC)
   target_link_libraries(mold PRIVATE ZLIB::ZLIB)
 else()
+  set(ZLIB_BUILD_EXAMPLES OFF CACHE INTERNAL "")
   add_subdirectory(third-party/zlib EXCLUDE_FROM_ALL)
   target_include_directories(zlibstatic INTERFACE third-party/zlib
     $<TARGET_PROPERTY:zlibstatic,BINARY_DIR>)
   target_link_libraries(mold PRIVATE zlibstatic)
 endif()
 
-# Find zstd compression library. Just like zlib, if libzstd.so is not
-# found, we compile a bundled one and statically-link it to mold.
+# Find BLAKE3 cryptographic hash library. Just like zlib, if libblkae3.so
+# is not found, we compile a bundled one and statically-link it to mold.
+find_package(BLAKE3 QUIET)
+if(BLAKE3_FOUND AND NOT MOLD_MOSTLY_STATIC)
+  target_link_libraries(mold PRIVATE BLAKE3::blake3)
+else()
+  function(mold_add_blake3)
+    set(BUILD_SHARED_LIBS OFF)
+    add_subdirectory(third-party/blake3/c EXCLUDE_FROM_ALL)
+    target_link_libraries(mold PRIVATE blake3)
+    target_include_directories(mold PUBLIC third-party/blake3/c)
+  endfunction()
+
+  mold_add_blake3()
+endif()
+
+# Find zstd compression library. If zstd.h is not found, we compile a
+# bundled one and statically-link it to mold.
 include(CheckIncludeFile)
 check_include_file(zstd.h HAVE_ZSTD_H)
 
-if(HAVE_ZSTD_H)
+if(HAVE_ZSTD_H AND NOT MOLD_MOSTLY_STATIC)
   target_link_libraries(mold PRIVATE zstd)
 else()
+  set(ZSTD_BUILD_PROGRAMS OFF)
+  set(ZSTD_BUILD_CONTRIB OFF)
+  set(ZSTD_BUILD_TESTS OFF)
+  set(ZSTD_MULTITHREAD_SUPPORT OFF)
+  set(ZSTD_BUILD_SHARED OFF)
+  set(ZSTD_BUILD_STATIC ON)
   add_subdirectory(third-party/zstd/build/cmake EXCLUDE_FROM_ALL)
-  target_compile_definitions(libzstd_static PRIVATE
-    ZSTD_BUILD_STATIC=1
-    ZSTD_BUILD_SHARED=0
-    ZSTD_BUILD_PROGRAMS=0
-    ZSTD_MULTITHREAD_SUPPORT=0
-    ZSTD_BUILD_TESTS=0)
   target_include_directories(mold PUBLIC third-party/zstd/lib)
   target_link_libraries(mold PRIVATE libzstd_static)
 endif()
@@ -138,12 +198,10 @@ endif()
 #
 # We enable mimalloc by default for 64-bit targets. It doesn't seem to
 # be stable on 32-bit targets.
-include(CheckCXXSourceCompiles)
-check_cxx_source_compiles(
-  "static_assert(sizeof(void *) == 4); int main() {}" P32)
+cmake_dependent_option(
+  MOLD_USE_MIMALLOC "Use mimalloc" ON
+  "CMAKE_SIZEOF_VOID_P EQUAL 8; NOT APPLE; NOT ANDROID; NOT OPENBSD; NOT MOLD_USE_ASAN; NOT MOLD_USE_TSAN" OFF)
 
-cmake_dependent_option(MOLD_USE_MIMALLOC "Use mimalloc" ON
-  "NOT APPLE; NOT ANDROID; NOT P32" OFF)
 cmake_dependent_option(
   MOLD_USE_SYSTEM_MIMALLOC "Use system or vendored mimalloc" OFF
   MOLD_USE_MIMALLOC OFF)
@@ -155,11 +213,11 @@ if(MOLD_USE_MIMALLOC)
   if(MOLD_USE_SYSTEM_MIMALLOC)
     find_package(mimalloc REQUIRED)
     target_link_libraries(mold PRIVATE mimalloc)
-    target_compile_definitions(mold PRIVATE USE_SYSTEM_MIMALLOC)
   else()
     function(mold_add_mimalloc)
       set(MI_BUILD_STATIC ON CACHE INTERNAL "")
       set(MI_BUILD_TESTS OFF CACHE INTERNAL "")
+      set(MI_NO_OPT_ARCH ON CACHE INTERNAL "")
       add_subdirectory(third-party/mimalloc EXCLUDE_FROM_ALL)
       target_compile_definitions(mimalloc-static PRIVATE MI_USE_ENVIRON=0)
       target_link_libraries(mold PRIVATE mimalloc-static)
@@ -176,7 +234,7 @@ endif()
 # to mold. If you want to link to the system's libtbb2.so, pass
 # -DMOLD_USE_SYSTEM_TBB=ON.
 option(MOLD_USE_SYSTEM_TBB "Use system or vendored TBB" OFF)
-if(MOLD_USE_SYSTEM_TBB)
+if(MOLD_USE_SYSTEM_TBB OR BLAKE3_USE_TBB)
   find_package(TBB REQUIRED)
   target_link_libraries(mold PRIVATE TBB::tbb)
 else()
@@ -192,11 +250,6 @@ else()
   mold_add_tbb()
 endif()
 
-# Check if this is a commercial version of mold (a.k.a. "sold")
-if(EXISTS "${CMAKE_SOURCE_DIR}/LICENSE.md")
-  set(MOLD_IS_SOLD ON)
-endif()
-
 # We always use Clang to build mold on Windows. MSVC can't compile mold.
 if(WIN32)
   if(MSVC AND NOT CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
@@ -225,12 +278,7 @@ if(NOT APPLE AND NOT WIN32)
   # Remove the default `lib` prefix
   set_target_properties(mold-wrapper PROPERTIES PREFIX "")
   target_link_libraries(mold-wrapper PRIVATE ${CMAKE_DL_LIBS})
-  target_sources(mold-wrapper PRIVATE elf/mold-wrapper.c)
-endif()
-
-if(NOT APPLE AND NOT WIN32 AND NOT MOLD_MOSTLY_STATIC)
-  find_package(OpenSSL REQUIRED COMPONENTS Crypto)
-  target_link_libraries(mold PRIVATE OpenSSL::Crypto)
+  target_sources(mold-wrapper PRIVATE src/mold-wrapper.c)
 endif()
 
 # If atomics doesn't work by default, add -latomic.
@@ -255,22 +303,21 @@ if(NOT APPLE AND NOT MSVC)
   target_link_options(mold PRIVATE -pthread)
 endif()
 
+check_symbol_exists(madvise sys/mman.h HAVE_MADVISE)
+check_symbol_exists(uname sys/utsname.h HAVE_UNAME)
+
 # Create a .cc file containing the current git hash for `mold --version`.
 add_custom_target(git_hash
   COMMAND ${CMAKE_COMMAND}
     -DSOURCE_DIR=${CMAKE_SOURCE_DIR}
-    -DOUTPUT_FILE=${CMAKE_BINARY_DIR}/git-hash.cc
-    -P ${CMAKE_SOURCE_DIR}/common/update-git-hash.cmake
-  DEPENDS common/update-git-hash.cmake
-  BYPRODUCTS git-hash.cc
+    -DOUTPUT_FILE=${CMAKE_BINARY_DIR}/mold-git-hash.h
+    -P ${CMAKE_SOURCE_DIR}/lib/update-git-hash.cmake
+  DEPENDS lib/update-git-hash.cmake
+  BYPRODUCTS mold-git-hash.h
   VERBATIM)
 
 add_dependencies(mold git_hash)
 
-# Create config.h file
-configure_file(common/config.h.in config.h)
-include_directories(${CMAKE_CURRENT_BINARY_DIR})
-
 # Almost all functions are template in mold which take a target type
 # (e.g. X86_64) as its type parameter. Since we suport more than 10
 # targets, compiling a single source file for all the targets is very
@@ -279,125 +326,131 @@ include_directories(${CMAKE_CURRENT_BINARY_DIR})
 # As a workaround, we create a .cc file for each target and spawn many
 # compiler instances. This is hacky but greatly reduces compile time
 # on a multicore machine.
-list(APPEND MOLD_ELF_TARGETS
-  X86_64 I386 ARM64 ARM32 RV32LE RV32BE RV64LE RV64BE
-  PPC32 PPC64V1 PPC64V2 S390X SPARC64 M68K SH4 ALPHA)
+#
+# You can build mold for a specific set of targets by passing, e.g.,
+# -DMOLD_TARGETS='X86_64;ARM64LE', though this is strongly discouraged
+# for build reproducibility. Use this option only if you build mold
+# frequently for your personal use; otherwise, always build mold with all
+# targets enabled. We provide this flag in the trust that you will not
+# abuse it, so please don’t betray that trust.
+set(MOLD_TARGETS
+  X86_64 I386 ARM64LE ARM64BE ARM32LE ARM32BE RV32LE RV32BE RV64LE
+  RV64BE PPC32 PPC64V1 PPC64V2 S390X SPARC64 M68K SH4LE SH4BE
+  LOONGARCH32 LOONGARCH64
+  CACHE STRING "List of supported targets")
 
-list(APPEND MOLD_ELF_TEMPLATE_FILES
-  elf/cmdline.cc
-  elf/dwarf.cc
-  elf/elf-main.cc
-  elf/gc-sections.cc
-  elf/icf.cc
-  elf/input-files.cc
-  elf/input-sections.cc
-  elf/linker-script.cc
-  elf/lto.cc
-  elf/mapfile.cc
-  elf/output-chunks.cc
-  elf/passes.cc
-  elf/relocatable.cc
-  elf/subprocess.cc
-  elf/thunks.cc
-  elf/tls.cc
+list(GET MOLD_TARGETS 0 MOLD_FIRST_TARGET)
+
+list(APPEND MOLD_TEMPLATE_FILES
+  src/arch-arm32.cc
+  src/arch-arm64.cc
+  src/arch-i386.cc
+  src/arch-loongarch.cc
+  src/arch-m68k.cc
+  src/arch-ppc32.cc
+  src/arch-ppc64v1.cc
+  src/arch-ppc64v2.cc
+  src/arch-riscv.cc
+  src/arch-s390x.cc
+  src/arch-sh4.cc
+  src/arch-sparc64.cc
+  src/arch-x86-64.cc
+  src/archive-file.cc
+  src/cmdline.cc
+  src/error.cc
+  src/filetype.cc
+  src/gc-sections.cc
+  src/gdb-index.cc
+  src/icf.cc
+  src/input-files.cc
+  src/input-sections.cc
+  src/linker-script.cc
+  src/main.cc
+  src/mapfile.cc
+  src/output-chunks.cc
+  src/passes.cc
+  src/relocatable.cc
+  src/shrink-sections.cc
+  src/thunks.cc
+  src/tls.cc
   )
 
-list(APPEND MOLD_MACHO_TARGETS X86_64 ARM64)
+if(WIN32 AND NOT MINGW)
+  list(APPEND MOLD_TEMPLATE_FILES src/lto-win32.cc)
+else()
+  list(APPEND MOLD_TEMPLATE_FILES src/lto-unix.cc)
+endif()
 
-list(APPEND MOLD_MACHO_TEMPLATE_FILES
-  macho/cmdline.cc
-  macho/dead-strip.cc
-  macho/input-files.cc
-  macho/input-sections.cc
-  macho/lto.cc
-  macho/macho-main.cc
-  macho/mapfile.cc
-  macho/output-chunks.cc
-  macho/tapi.cc
+if(WIN32)
+  list(APPEND MOLD_TEMPLATE_FILES
+    src/output-file-win32.cc
+    src/subprocess-win32.cc
+    )
+else()
+  list(APPEND MOLD_TEMPLATE_FILES
+    src/output-file-unix.cc
+    src/subprocess-unix.cc
   )
+endif()
 
 function(mold_instantiate_templates SOURCE TARGET)
   set(PATH ${CMAKE_BINARY_DIR}/${SOURCE}.${TARGET}.cc)
-  file(WRITE ${PATH} "#define MOLD_${TARGET} 1
+  if(NOT EXISTS ${PATH})
+    file(WRITE ${PATH} "#define MOLD_${TARGET} 1
 #define MOLD_TARGET ${TARGET}
 #include \"${CMAKE_SOURCE_DIR}/${SOURCE}\"
 ")
+  endif()
   target_sources(mold PRIVATE ${PATH})
 endfunction()
 
-foreach (SOURCE IN LISTS MOLD_ELF_TEMPLATE_FILES)
-  foreach(TARGET IN LISTS MOLD_ELF_TARGETS)
+foreach (SOURCE IN LISTS MOLD_TEMPLATE_FILES)
+  foreach(TARGET IN LISTS MOLD_TARGETS)
     mold_instantiate_templates(${SOURCE} ${TARGET})
+    set(HAVE_TARGET_${TARGET} 1)
   endforeach()
 endforeach()
 
-if(MOLD_IS_SOLD)
-  foreach (SOURCE IN LISTS MOLD_MACHO_TEMPLATE_FILES)
-    foreach(TARGET IN LISTS MOLD_MACHO_TARGETS)
-      mold_instantiate_templates(${SOURCE} ${TARGET})
-    endforeach()
-  endforeach()
-endif()
-
 # Add other non-template source files.
 target_sources(mold PRIVATE
-  common/compress.cc
-  common/demangle.cc
-  common/filepath.cc
-  common/glob.cc
-  common/hyperloglog.cc
-  common/main.cc
-  common/multi-glob.cc
-  common/perf.cc
-  common/tar.cc
-  common/uuid.cc
-  elf/arch-alpha.cc
-  elf/arch-arm32.cc
-  elf/arch-arm64.cc
-  elf/arch-i386.cc
-  elf/arch-m68k.cc
-  elf/arch-ppc32.cc
-  elf/arch-ppc64v1.cc
-  elf/arch-ppc64v2.cc
-  elf/arch-riscv.cc
-  elf/arch-s390x.cc
-  elf/arch-sh4.cc
-  elf/arch-sparc64.cc
-  elf/arch-x86-64.cc
-  elf/elf.cc
-  git-hash.cc
+  lib/aho-corasick.cc
+  lib/compress.cc
+  lib/crc32.cc
+  lib/demangle.cc
+  lib/filepath.cc
+  lib/glob.cc
+  lib/hyperloglog.cc
+  lib/perf.cc
+  lib/random.cc
+  lib/tar.cc
+  src/elf.cc
+  src/entry.cc
   third-party/rust-demangle/rust-demangle.c
   )
 
-if(MOLD_IS_SOLD)
+if(WIN32)
   target_sources(mold PRIVATE
-    macho/arch-arm64.cc
-    macho/arch-x86-64.cc
-    macho/yaml.cc
+    src/jobs-win32.cc
+    src/mapped-file-win32.cc
+    src/signal-win32.cc
+    )
+else()
+  target_sources(mold PRIVATE
+    src/jobs-unix.cc
+    src/mapped-file-unix.cc
+    src/signal-unix.cc
     )
 endif()
 
-# Add frequently included header files for pre-compiling.
-# target_precompile_headers is supported by CMake 3.16.0 or newer.
-if(${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.16.0")
-  if(MOLD_IS_SOLD)
-    target_precompile_headers(mold PRIVATE
-      "$<$<COMPILE_LANGUAGE:CXX>:${CMAKE_SOURCE_DIR}/elf/mold.h>"
-      "$<$<COMPILE_LANGUAGE:CXX>:${CMAKE_SOURCE_DIR}/macho/mold.h>")
-  else()
-    target_precompile_headers(mold PRIVATE
-      "$<$<COMPILE_LANGUAGE:CXX>:${CMAKE_SOURCE_DIR}/elf/mold.h>")
-  endif()
-
-  # ccache needs this flag along with `sloppiness = pch_defines,time_macros`
-  # to enable caching
-  target_compile_options(mold PRIVATE -fpch-preprocess)
-endif()
+# Create config.h file
+configure_file(lib/config.h.in config.h)
+include_directories(${CMAKE_CURRENT_BINARY_DIR})
 
+# Test configs
 include(CTest)
 
 if(BUILD_TESTING)
-  # Create the ld and ld64 symlinks required for testing
+  # Create the ld symlinks required for testing
   if(NOT WIN32)
     add_custom_command(
       TARGET mold POST_BUILD
@@ -405,33 +458,17 @@ if(BUILD_TESTING)
       BYPRODUCTS ld
       WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
       VERBATIM)
-
-    if(MOLD_IS_SOLD)
-      add_custom_command(
-        TARGET mold POST_BUILD
-        COMMAND ${CMAKE_COMMAND} -E create_symlink mold ld64
-        BYPRODUCTS ld64
-        WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
-        VERBATIM)
-    endif()
   endif()
 
-  if(${APPLE})
-    if(MOLD_IS_SOLD)
-      add_subdirectory(test/macho)
-    endif()
-  elseif(${UNIX})
-    add_subdirectory(test/elf)
+  if(${UNIX})
+    add_subdirectory(test)
   endif()
 endif()
 
 if(NOT CMAKE_SKIP_INSTALL_RULES)
   install(TARGETS mold RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
   install(FILES docs/mold.1 DESTINATION ${CMAKE_INSTALL_MANDIR}/man1/)
-
-  if(EXISTS "${CMAKE_SOURCE_DIR}/LICENSE")
-    install(FILES LICENSE DESTINATION ${CMAKE_INSTALL_DOCDIR})
-  endif()
+  install(FILES LICENSE DESTINATION ${CMAKE_INSTALL_DOCDIR})
 
   function(mold_install_relative_symlink OLD NEW)
     install(CODE "
@@ -445,19 +482,12 @@ if(NOT CMAKE_SKIP_INSTALL_RULES)
       file(CREATE_LINK \${OLD_REL} \$ENV{DESTDIR}\${NEW_ABS} SYMBOLIC)")
   endfunction()
 
-  mold_install_relative_symlink(${CMAKE_INSTALL_BINDIR}/mold${CMAKE_EXECUTABLE_SUFFIX}
-    ${CMAKE_INSTALL_LIBEXECDIR}/mold/ld${CMAKE_EXECUTABLE_SUFFIX})
-  mold_install_relative_symlink(${CMAKE_INSTALL_BINDIR}/mold${CMAKE_EXECUTABLE_SUFFIX}
-    ${CMAKE_INSTALL_BINDIR}/ld.mold${CMAKE_EXECUTABLE_SUFFIX})
-  mold_install_relative_symlink(${CMAKE_INSTALL_MANDIR}/man1/mold.1
-    ${CMAKE_INSTALL_MANDIR}/man1/ld.mold.1)
-
-  if(MOLD_IS_SOLD)
-    mold_install_relative_symlink(${CMAKE_INSTALL_BINDIR}/mold
-      ${CMAKE_INSTALL_BINDIR}/ld64.mold)
-    mold_install_relative_symlink(${CMAKE_INSTALL_BINDIR}/mold
-      ${CMAKE_INSTALL_BINDIR}/ld.sold)
-    mold_install_relative_symlink(${CMAKE_INSTALL_BINDIR}/mold
-      ${CMAKE_INSTALL_BINDIR}/ld64.sold)
+  if(NOT WIN32)
+    mold_install_relative_symlink(${CMAKE_INSTALL_BINDIR}/mold${CMAKE_EXECUTABLE_SUFFIX}
+      ${CMAKE_INSTALL_LIBEXECDIR}/mold/ld${CMAKE_EXECUTABLE_SUFFIX})
+    mold_install_relative_symlink(${CMAKE_INSTALL_BINDIR}/mold${CMAKE_EXECUTABLE_SUFFIX}
+      ${CMAKE_INSTALL_BINDIR}/ld.mold${CMAKE_EXECUTABLE_SUFFIX})
+    mold_install_relative_symlink(${CMAKE_INSTALL_MANDIR}/man1/mold.1
+      ${CMAKE_INSTALL_MANDIR}/man1/ld.mold.1)
   endif()
 endif()

CONTRIBUTING.md

@@ -1,44 +0,0 @@
-# Contributing to mold
-
-We request all patches to mold to be released under the dual license
-of the GNU AGPLv3 and the MIT license. Please read the following and
-sign-off your patch as an indication of agreement.
-
-> ## Developer's Certificate of Origin
->
-> By making a contribution to this project, I certify that:
->
->  1. The contribution was created in whole or in part by me and I
->     have the right to submit it under the Dual License of the GNU
->     AGPLv3 and the MIT license; or
->
->  2. The contribution is based upon previous work that, to the best
->     of my knowledge, is covered under the the Dual License and I
->     have the right under the Dual License to submit that work with
->     modifications, whether created in whole or in part by me, under
->     the Dual License (unless I am permitted to submit under
->     different licenses), as indicated in the file; or
->
->  3. The contribution was provided directly to me by some other
->     person who certified (1), (2) or (3) and I have not modified it.
->
->  4. I understand and agree that this project and the contribution
->     are public and that a record of the contribution (including all
->     personal information I submit with it, including my sign-off) is
->     maintained indefinitely and may be redistributed consistent with
->     this project or the open source license(s) involved.
-
-If you agree, you just add a line saying:
-
-```
-Signed-off-by: Random J Developer <[email protected]>
-```
-
-using your real name (sorry, no pseudonyms or anonymous contributions.)
-This will be done for you automatically if you use ``git commit -s``.
-Reverts should also include "Signed-off-by". ``git revert -s`` does that
-for you.
-
-We assume that any contribution that's 10 lines or less does not meet
-the threshold of originality and therefore copyright does not apply.
-You don't need to add a "Signed-off-by" line to such small patches.

README.md

@@ -1,133 +1,117 @@
 # mold: A Modern Linker
 
-[![CI](https://github.com/rui314/mold/actions/workflows/ci.yml/badge.svg)](https://github.com/rui314/mold/actions/workflows/ci.yml)
-[![build result](https://build.opensuse.org/projects/home:marxin:mold/packages/mold/badge.svg?type=default)](https://build.opensuse.org/package/show/home:marxin:mold/mold)
+mold is a faster drop-in replacement for existing Unix linkers. It is several
+times quicker than the LLVM lld linker, the second-fastest open-source linker,
+which I initially developed a few years ago. mold aims to enhance developer
+productivity by minimizing build time, particularly in rapid
+debug-edit-rebuild cycles.
 
-<i>This is a repo of a free, AGPL-licensed version of the linker.
-If you are looking for a commercial, non-AGPL version of the same linker,
-please visit the
-[repo of the sold linker](https://github.com/bluewhalesystems/sold).</i>
+Here is a performance comparison of GNU ld, GNU gold, LLVM lld, and
+mold when linking final debuginfo-enabled executables for major large
+programs on a simulated 16-core, 32-thread machine.
 
-mold is a faster drop-in replacement for existing Unix linkers.
-It is several times faster than the LLVM lld linker, the second-fastest
-open-source linker which I originally created a few years ago.
-mold is designed to increase developer productivity by reducing
-build time, especially in rapid debug-edit-rebuild cycles.
+![Link speed comparison](docs/chart.svg)
 
-Here is a performance comparison of GNU gold, LLVM lld, and mold for
-linking final debuginfo-enabled executables of major large programs
-on a simulated 8-core 16-threads machine.
+| Program (linker output size)  | GNU ld | GNU gold | LLVM lld | mold
+|-------------------------------|--------|----------|----------|------
+| MySQL 8.3 (0.47 GiB)          | 10.84s | 7.47s    | 1.64s    | 0.46s
+| Clang 19 (1.56 GiB)           | 42.07s | 33.13s   | 5.20s    | 1.35s
+| Chromium 124 (1.35 GiB)       | N/A    | 27.40s   | 6.10s    | 1.52s
 
-![Link speed comparison](docs/comparison.png)
-
-| Program (linker output size)  | GNU gold | LLVM lld | mold
-|-------------------------------|----------|----------|--------
-| Chrome 96 (1.89 GiB)          | 53.86s   | 11.74s   | 2.21s
-| Clang 13 (3.18 GiB)           | 64.12s   | 5.82s    | 2.90s
-| Firefox 89 libxul (1.64 GiB)  | 32.95s   | 6.80s    | 1.42s
-
-mold is so fast that it is only 2x _slower_ than `cp` on the same
-machine. Feel free to [file a bug](https://github.com/rui314/mold/issues)
-if you find mold is not faster than other linkers.
+mold is so fast that it is only 2x _slower_ than the `cp` command on the same
+machine. If you find that mold is not faster than other linkers, feel
+free to [file a bug report](https://github.com/rui314/mold/issues).
 
 mold supports x86-64, i386, ARM64, ARM32, 64-bit/32-bit little/big-endian
-RISC-V, 32-bit PowerPC, 64-bit big-endian PowerPC ELFv1, 64-bit
-little-endian PowerPC ELFv2, s390x, SPARC64, m68k, SH-4 and DEC Alpha.
+RISC-V, 32-bit PowerPC, 64-bit big-endian PowerPC ELFv1, 64-bit little-endian
+PowerPC ELFv2, s390x, 64-bit/32-bit LoongArch, SPARC64, m68k, and SH-4.
 
-mold/macOS is commercial software. For mold/macOS, please visit
-https://github.com/bluewhalesystems/sold.
+## Why does linking speed matter?
 
-## Why does the speed of linking matter?
+If you are using a compiled language such as C, C++, or Rust, a build consists
+of two phases. In the first phase, a compiler compiles source files into
+object files (`.o` files). In the second phase, a linker takes all object
+files and combines them into a single executable or shared library file.
 
-If you are using a compiled language such as C, C++ or Rust, a build
-consists of two phases. In the first phase, a compiler compiles
-source files into object files (`.o` files). In the second phase,
-a linker takes all object files to combine them into a single executable
-or a shared library file.
+The second phase can be time-consuming if your build output is large. mold can
+speed up this process, saving you time and preventing distractions while
+waiting for a lengthy build to finish. The difference is most noticeable
+during rapid debug-edit-rebuild cycles.
 
-The second phase takes a long time if your build output is large.
-mold can make it faster, saving your time and keeping you from being
-distracted while waiting for a long build to finish. The difference is
-most noticeable when you are in rapid debug-edit-rebuild cycles.
+## Installation
 
-## Install
-
-Binary packages for the following systems are currently available.
+Binary packages for the following systems are currently available:
 
 [![Packaging status](https://repology.org/badge/vertical-allrepos/mold.svg)](https://repology.org/project/mold/versions)
 
-## How to build
+## How to Build
 
-mold is written in C++20, so if you build mold yourself, you need a
-recent version of a C++ compiler and a C++ standard library. GCC 10.2
-or Clang 12.0.0 (or later) as well as libstdc++ 10 or libc++ 7 (or
-later) are recommended.
+mold is written in C++20, so if you build mold yourself, you will need a
+recent version of a C++ compiler and a C++ standard library. We recommend GCC
+10.2 or Clang 16.0.0 (or later) and libstdc++ 10 or libc++ 7 (or later).
 
-### Install dependencies
+### Install Dependencies
 
 To install build dependencies, run `./install-build-deps.sh` in this
-directory. It recognizes your Linux distribution and tries to install
-necessary packages. You may want to run it as root.
+directory. It will detect your Linux distribution and attempt to install the
+necessary packages. You may need to run it as root.
 
 ### Compile mold
 
 ```shell
-git clone https://github.com/rui314/mold.git
-mkdir mold/build
-cd mold/build
-git checkout v1.10.0
-../install-build-deps.sh
-cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=c++ ..
-cmake --build . -j $(nproc)
-sudo cmake --install .
+git clone --branch stable https://github.com/rui314/mold.git
+cd mold
+./install-build-deps.sh
+cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_CXX_COMPILER=c++ -B build
+cmake --build build -j$(nproc)
+sudo cmake --build build --target install
 ```
 
-You may need to pass a C++20 compiler command name to `cmake`.
-In the above case, `c++` is passed. If it doesn't work for you,
-try a specific version of a compiler such as `g++-10` or `clang++-12`.
+You might need to pass a C++20 compiler command name to `cmake`. In the
+example above, `c++` is passed. If that doesn't work for you, try a specific
+version of a compiler, such as `g++-10` or `clang++-12`.
 
-By default, `mold` is installed to `/usr/local/bin`. You can change
-that by passing `-DCMAKE_INSTALL_PREFIX=<directory>`. For other cmake
-options, see the comments in `CMakeLists.txt`.
+By default, `mold` is installed to `/usr/local/bin`. You can change the
+installation location by passing `-DCMAKE_INSTALL_PREFIX=<directory>`.
+For other cmake options, see the comments in `CMakeLists.txt`.
 
-If you don't use a recent enough Linux distribution, or if for any reason
-`cmake` in the above commands doesn't work for you, you can use Docker to
-build it in a Docker environment. To do so, just run `./dist.sh` in this
-directory instead of `cmake`. The shell script pulls a Docker image,
-builds mold and auxiliary files inside it, and packs them into a
-single tar file `mold-$version-$arch-linux.tar.gz`.  You can extract
-the tar file anywhere and use `mold` executable in it.
+If you are not using a recent enough Linux distribution, or if `cmake` does
+not work for you for any reason, you can use Podman to build mold in a
+container. To do so, run `./dist.sh` in this directory instead of using
+`cmake`. The shell script will pull a container image, build mold and auxiliary
+files inside it, and package them into a single tar file named
+`dist/mold-$version-$arch-linux.tar.gz`. You can extract the tar file anywhere
+and use the mold executable in it.
 
 ## How to use
 
 <details><summary>A classic way to use mold</summary>
 
-On Unix, the linker command (which is usually `/usr/bin/ld`) is
-invoked indirectly by the compiler driver (which is usually `cc`,
-`gcc` or `clang`), which is typically in turn indirectly invoked by
-`make` or some other build system command.
+On Unix, the linker command (usually `/usr/bin/ld`) is indirectly invoked by
+the compiler driver (typically `cc`, `gcc`, or `clang`), which is in turn
+indirectly invoked by `make` or other build system commands.
 
-If you can specify an additional command line option to your compiler
-driver by modifying build system's config files, add one of the
-following flags to use `mold` instead of `/usr/bin/ld`:
+If you can specify an additional command line option for your compiler driver
+by modifying the build system's config files, add one of the following flags
+to use mold instead of `/usr/bin/ld`:
 
-- Clang: pass `-fuse-ld=mold`
+- For Clang: pass `-fuse-ld=mold`
 
-- GCC 12.1.0 or later: pass `-fuse-ld=mold`
+- For GCC 12.1.0 or later: pass `-fuse-ld=mold`
 
-- GCC before 12.1.0: `-fuse-ld` does not accept `mold` as a valid
-  argument, so you need to use `-B` option instead. `-B` is an option
-  to tell GCC where to look for external commands such as `ld`.
+- For GCC before 12.1.0: the `-fuse-ld` option does not accept `mold` as a
+  valid argument, so you need to use the `-B` option instead. The `-B` option
+  tells GCC where to look for external commands like `ld`.
 
-  If you have installed mold with `make install`, there should be a
-  directory named `/usr/libexec/mold` (or `/usr/local/libexec/mold`,
-  depending on your `$PREFIX`), and `ld` command should be there. The
-  `ld` is actually a symlink to `mold`. So, all you need is to pass
-  `-B/usr/libexec/mold` (or `-B/usr/local/libexec/mold`) to GCC.
+  If you have installed mold with `make install`, there should be a directory
+  named `/usr/libexec/mold` (or `/usr/local/libexec/mold`, depending on your
+  `$PREFIX`), and the `ld` command should be there. The `ld` is actually a
+  symlink to `mold`. So, all you need is to pass `-B/usr/libexec/mold` (or
+  `-B/usr/local/libexec/mold`) to GCC.
 
 If you haven't installed `ld.mold` to any `$PATH`, you can still pass
-`-fuse-ld=/absolute/path/to/mold` to clang to use mold. GCC does not
-take an absolute path as an argument for `-fuse-ld` though.
+`-fuse-ld=/absolute/path/to/mold` to clang to use mold. However, GCC does not
+accept an absolute path as an argument for `-fuse-ld`.
 
 </details>
 
@@ -136,37 +120,24 @@ take an absolute path as an argument for `-fuse-ld` though.
 Create `.cargo/config.toml` in your project directory with the following:
 
 ```toml
-[target.x86_64-unknown-linux-gnu]
+[target.'cfg(target_os = "linux")']
 linker = "clang"
 rustflags = ["-C", "link-arg=-fuse-ld=/path/to/mold"]
 ```
 
-where `/path/to/mold` is an absolute path to `mold` exectuable. In the
-above example, we use `clang` as a linker driver as it can always take
-the `-fuse-ld` option. If your GCC is recent enough to recognize the
-option, you may be able to remove the `linker = "clang"` line.
+where `/path/to/mold` is an absolute path to the mold executable. In the
+example above, we use `clang` as a linker driver since it always accepts the
+`-fuse-ld` option. If your GCC is recent enough to recognize the option, you
+may be able to remove the `linker = "clang"` line.
 
 ```toml
-[target.x86_64-unknown-linux-gnu]
-rustflags = ["-C", "link-arg=-fuse-ld=/path/to/mold"]
+[target.'cfg(target_os = "linux")']
+rustflags = ["-C", "link-arg=-fuse-ld=mold"]
 ```
 
-If you want to use mold for all projects, put the above snippet to
+If you want to use mold for all projects, add the above snippet to
 `~/.cargo/config.toml`.
 
-If you are using macOS, you can modify `config.toml` in a similar manner.
-Here is an example with `mold` installed via [Homebrew](https://brew.sh).
-
-```toml
-[target.x86_64-apple-darwin]
-linker = "clang"
-rustflags = ["-C", "link-arg=-fuse-ld=mold"]
-
-[target.aarch64-apple-darwin]
-linker = "clang"
-rustflags = ["-C", "link-arg=-fuse-ld=mold"]
-```
-
 </details>
 
 <details><summary>If you are using Nim</summary>
@@ -178,67 +149,54 @@ when findExe("mold").len > 0 and defined(linux):
   switch("passL", "-fuse-ld=mold")
 ```
 
-where `mold` must be included in the PATH environment variable. In this example
-The above example uses `gcc` as the linker driver.
-Use the `fuse-ld` option. If your GCC is recent enough to recognize this option.
+where `mold` must be included in the `PATH` environment variable. In this
+example, `gcc` is used as the linker driver. Use the `-fuse-ld` option if your
+GCC is recent enough to recognize this option.
 
-If you want to use mold for all projects, put the above snippet to `~/.config/config.nims`.
+If you want to use mold for all projects, add the above snippet to
+`~/.config/config.nims`.
 
-If you are using macOS, you can modify config.nims in a similar manner. Here is an example with mold installed via Homebrew.
+</details>
 
-```nim
-when findExe("ld64.mold").len > 0 and defined(macosx):
-  switch("passL", "-fuse-ld=ld64.mold")
-```
+<details><summary>If you are using Conan package manager</summary>
+
+You can configure [Conan](https://github.com/conan-io) to download the latest
+version of `mold` and use it as the linker when building your dependencies and
+projects from source. Please see the instructions [here](https://conan.io/center/recipes/mold).
 
 </details>
 
 <details><summary>mold -run</summary>
 
-It is sometimes very hard to pass an appropriate command line option
-to `cc` to specify an alternative linker.  To deal with the situation,
-mold has a feature to intercept all invocations of `ld`, `ld.lld` or
-`ld.gold` and redirect it to itself. To use the feature, run `make`
-(or another build command) as a subcommand of mold as follows:
+It is sometimes very hard to pass an appropriate command line option to `cc`
+to specify an alternative linker. To address this situation, mold has a
+feature to intercept all invocations of `ld`, `ld.bfd`, `ld.lld`, or `ld.gold`
+and redirect them to itself. To use this feature, run `make` (or another build
+command) as a subcommand of mold as follows:
 
 ```shell
 mold -run make <make-options-if-any>
 ```
 
-Internally, mold invokes a given command with `LD_PRELOAD` environment
-variable set to its companion shared object file. The shared object
-file intercepts all function calls to `exec(3)`-family functions to
-replace `argv[0]` with `mold` if it is `ld`, `ld.gold` or `ld.lld`.
-
-</details>
-
-<details><summary>On macOS</summary>
-
-mold/macOS is available as an alpha version. It can be used to build not
-only macOS apps but also iOS apps because their binary formats are the same.
-
-The command name of mold/macOS is `ld64.mold`. If you build mold on macOS,
-it still produces `mold` and `ld.mold`, but these executables are useful
-only for cross compilation (i.e. building Linux apps on macOS.)
-
-If you find any issue with mold/macOS, please file it to
-<a href=https://github.com/rui314/mold/issues>our GitHub Issues</a>.
+Internally, mold invokes a given command with the `LD_PRELOAD` environment
+variable set to its companion shared object file. The shared object file
+intercepts all function calls to `exec(3)`-family functions to replace
+`argv[0]` with `mold` if it is `ld`, `ld.bf`, `ld.gold`, or `ld.lld`.
 
 </details>
 
 <details><summary>GitHub Actions</summary>
 
-You can use our <a href=https://github.com/rui314/setup-mold>setup-mold</a>
-GitHub Action to speed up GitHub-hosted continuous build. GitHub Actions
-runs on a two-core machine, but mold is still significantly faster than
-the default GNU linker there especially when a program being linked is
-large.
+You can use our [setup-mold](https://github.com/rui314/setup-mold) GitHub
+Action to speed up GitHub-hosted continuous builds. Although GitHub Actions
+run on a 4 core machine, mold is still significantly faster than the default
+GNU linker, especially when linking large programs.
 
 </details>
 
 <details><summary>Verify that you are using mold</summary>
 
-mold leaves its identification string in `.comment` section in an output
+mold leaves its identification string in the `.comment` section of an output
 file. You can print it out to verify that you are actually using mold.
 
 ```shell
@@ -249,75 +207,69 @@ String dump of section '.comment':
   [    2b]  mold 9a1679b47d9b22012ec7dfbda97c8983956716f7
 ```
 
-If `mold` is in `.comment`, the file is created by mold.
+If `mold` is present in the `.comment` section, the file was created by mold.
 
 </details>
 
 <details><summary>Online manual</summary>
 
-Since mold is a drop-in replacement, you should be able to use it
-without reading its manual. But just in case you need it, it's available
-online at <a href=https://rui314.github.io/mold.html>here</a>.
-You can also read the same manual by `man mold`.
+Since mold is a drop-in replacement, you should be able to use it without
+reading its manual. However, if you need it, [mold's man page](docs/mold.md)
+is available online. You can read the same manual by running `man mold`.
 
 </details>
 
 ## Why is mold so fast?
 
-One reason is because it simply uses faster algorithms and efficient
-data structures than other linkers do. The other reason is that the
-new linker is highly parallelized.
+One reason is that it utilizes faster algorithms and more efficient data
+structures compared to other linkers. Another reason is that mold is highly
+parallelized.
 
-Here is a side-by-side comparison of per-core CPU usage of lld (left)
-and mold (right). They are linking the same program, Chromium
-executable.
+Here is a side-by-side comparison of per-core CPU usage for lld (left) and
+mold (right), linking the same program, a Chromium executable.
 
 ![CPU usage comparison in htop animation](docs/htop.gif)
 
-As you can see, mold uses all available cores throughout its execution
-and finishes quickly. On the other hand, lld failed to use available
-cores most of the time. In this demo, the maximum parallelism is
-artificially capped to 16 so that the bars fit in the GIF.
+As you can see, mold uses all available cores throughout its execution and
+finishes quickly. In contrast, lld fails to utilize available cores most of
+the time. In this demo, the maximum parallelism is artificially capped at 16,
+so that the bars fit in the GIF.
 
-For details, please read [design notes](docs/design.md).
-
-## License
-
-mold is available under AGPL. Note that that does not mean that you
-have to license your program under AGPL if you use mold to link your
-program. An output of the mold linker is a derived work of the object
-files and libraries you pass to the linker but not a derived work of
-the mold linker itself.
-
-Besides that, you can also buy a commercial, non-AGPL license with
-technical support from our company, Blue Whale Systems PTE LTD. If you
-are a big company, please consider obtaining it before making hundreds
-or thousands of developers of your company to depend on mold. mold is
-mostly a single-person open-source project, and just like other
-open-source projects, we are not legally obligated to keep maintaining
-it. A legally-binding commercial license contract addresses the
-concern. By purchasing a license, you are guaranteed that mold will be
-maintained for you. Please [contact us](mailto:[email protected])
-for a commercial license inquiry.
+For details, please see the [design notes](docs/design.md).
 
 ## Sponsors
 
-We accept donations via [GitHub Sponsors](https://github.com/sponsors/rui314)
-and [OpenCollective](https://opencollective.com/mold-linker).
-We thank you to everybody who sponsors our project. In particular,
-we'd like to acknowledge the following people and organizations who
-have sponsored $128/month or more:
+It is taken for granted nowadays that compiler toolchains can be easily
+installed and used for free, and people may not think too much about the
+individuals behind these "free tools". mold supports many projects, but it
+is essentially a one-person project. This situation is similar to the one
+depicted in the following xkcd illustration.
+
+[![xkcd 2347](https://imgs.xkcd.com/comics/dependency.png)](https://xkcd.com/2347)
+
+If you think that the "Nebraska guy" should be rewarded, please consider
+becoming our [GitHub sponsor](https://github.com/sponsors/rui314)!
+
+We thank everyone who sponsors our project. In particular, we'd like to acknowledge
+the following people and organizations who have sponsored $128/month or more:
 
 ### Corporate sponsors
 
-<a href="https://mercury.com/"><img src="docs/mercury-logo.png" align=center height=120 width=400 alt=Mercury></a>
+<a href="https://mercury.com"><img src="docs/mercury-logo.png" align=center height=120 width=400 alt=Mercury></a>
 
-- [Uber](https://uber.com)
+<a href="https://cybozu-global.com"><img src="docs/cyboze-logo.png" align=center height=120 width=133 alt=Cybozu></a>
+
+<a href="https://www.emergetools.com"><img src="docs/emerge-tools-logo.png" align=center height=120 width=240 alt="Emerge Tools"></a><br>
+
+- [G-Research](https://www.gresearch.co.uk)
 - [Signal Slot Inc.](https://github.com/signal-slot)
+- [GlareDB](https://github.com/GlareDB)
 
 ### Individual sponsors
 
-- [300baud](https://github.com/300baud)
-- [Johan Andersson](https://github.com/repi)
 - [Wei Wu](https://github.com/lazyparser)
 - [kyle-elliott](https://github.com/kyle-elliott)
+- [Bryant Biggs](https://github.com/bryantbiggs)
+- [kraptor23](https://github.com/kraptor23)
+- [Jinkyu Yi](https://github.com/jincreator)
+- [Pedro Navarro](https://github.com/pedronavf)

common/Dockerfile

@@ -1,23 +0,0 @@
-# This dockerfile creates a reproducible build environment for mold.
-#
-# $ docker buildx create --use
-# $ docker buildx build --platform x86_64,aarch64,arm,ppc64le,s390x -t rui314/mold-builder:latest --push .
-
-FROM ubuntu:18.04
-ENV TZ=Europe/London
-RUN apt-get update && \
-  apt-get install -y --no-install-recommends software-properties-common && \
-  add-apt-repository -y ppa:ubuntu-toolchain-r/test && \
-  apt-get update && \
-  apt-get install -y --no-install-recommends build-essential wget libstdc++-11-dev zlib1g-dev gcc-10 g++-10 python3 && \
-  \
-  mkdir /openssl && cd /openssl && \
-  wget -O- -q https://www.openssl.org/source/openssl-3.0.7.tar.gz | tar --strip-components=1 -xzf - && \
-  ./Configure --prefix=/usr/local --libdir=lib && \
-  make -j$(nproc) && \
-  make -j$(nproc) install && \
-  ldconfig && \
-  mkdir /cmake && cd /cmake && \
-  wget -O- -q https://github.com/Kitware/CMake/releases/download/v3.24.2/cmake-3.24.2.tar.gz | tar --strip-components=1 -xzf - && \
-  ./bootstrap --parallel=$(nproc) && make -j$(nproc) && make -j$(nproc) install && \
-  rm -rf /var/lib/apt/lists/* /cmake /openssl

common/cmdline.h

@@ -1,90 +0,0 @@
-#pragma once
-
-#include "common.h"
-
-namespace mold {
-
-template <typename Context>
-std::vector<std::string_view>
-read_response_file(Context &ctx, std::string_view path) {
-  std::vector<std::string_view> vec;
-  MappedFile<Context> *mf = MappedFile<Context>::must_open(ctx, std::string(path));
-  u8 *data = mf->data;
-
-  auto read_quoted = [&](i64 i, char quote) {
-    std::string buf;
-    while (i < mf->size && data[i] != quote) {
-      if (data[i] == '\\') {
-        buf.append(1, data[i + 1]);
-        i += 2;
-      } else {
-        buf.append(1, data[i++]);
-      }
-    }
-    if (i >= mf->size)
-      Fatal(ctx) << path << ": premature end of input";
-    vec.push_back(save_string(ctx, buf));
-    return i + 1;
-  };
-
-  auto read_unquoted = [&](i64 i) {
-    std::string buf;
-
-    while (i < mf->size) {
-      if (data[i] == '\\' && i + 1 < mf->size) {
-        buf.append(1, data[i + 1]);
-        i += 2;
-        continue;
-      }
-
-      if (!isspace(data[i])) {
-        buf.append(1, data[i++]);
-        continue;
-      }
-
-      break;
-    }
-
-    vec.push_back(save_string(ctx, buf));
-    return i;
-  };
-
-  for (i64 i = 0; i < mf->size;) {
-    if (isspace(data[i]))
-      i++;
-    else if (data[i] == '\'')
-      i = read_quoted(i + 1, '\'');
-    else if (data[i] == '\"')
-      i = read_quoted(i + 1, '\"');
-    else
-      i = read_unquoted(i);
-  }
-  return vec;
-}
-
-// Replace "@path/to/some/text/file" with its file contents.
-template <typename Context>
-std::vector<std::string_view> expand_response_files(Context &ctx, char **argv) {
-  std::vector<std::string_view> vec;
-  for (i64 i = 0; argv[i]; i++) {
-    if (argv[i][0] == '@')
-      append(vec, read_response_file(ctx, argv[i] + 1));
-    else
-      vec.push_back(argv[i]);
-  }
-  return vec;
-}
-
-static inline std::string_view string_trim(std::string_view str) {
-  size_t pos = str.find_first_not_of(" \t");
-  if (pos == str.npos)
-    return "";
-  str = str.substr(pos);
-
-  pos = str.find_last_not_of(" \t");
-  if (pos == str.npos)
-    return str;
-  return str.substr(0, pos + 1);
-}
-
-} // namespace mold

common/common.h

@@ -1,939 +0,0 @@
-#pragma once
-
-#include "integers.h"
-
-#include <array>
-#include <atomic>
-#include <bit>
-#include <bitset>
-#include <cassert>
-#include <cstdio>
-#include <cstring>
-#include <fcntl.h>
-#include <filesystem>
-#include <iostream>
-#include <mutex>
-#include <optional>
-#include <span>
-#include <sstream>
-#include <string>
-#include <string_view>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <tbb/concurrent_vector.h>
-#include <tbb/enumerable_thread_specific.h>
-#include <vector>
-
-#ifdef _WIN32
-# include <io.h>
-#else
-# include <sys/mman.h>
-# include <unistd.h>
-#endif
-
-#define XXH_INLINE_ALL 1
-#include "../third-party/xxhash/xxhash.h"
-
-#ifdef NDEBUG
-# define unreachable() __builtin_unreachable()
-#else
-# define unreachable() assert(0 && "unreachable")
-#endif
-
-// __builtin_assume() is supported only by clang, and [[assume]] is
-// available only in C++23, so we use this macro when giving a hint to
-// the compiler's optimizer what's true.
-#define ASSUME(x) do { if (!(x)) __builtin_unreachable(); } while (0)
-
-inline uint64_t hash_string(std::string_view str) {
-  return XXH3_64bits(str.data(), str.size());
-}
-
-class HashCmp {
-public:
-  static size_t hash(const std::string_view &k) {
-    return hash_string(k);
-  }
-
-  static bool equal(const std::string_view &k1, const std::string_view &k2) {
-    return k1 == k2;
-  }
-};
-
-namespace mold {
-
-using namespace std::literals::string_literals;
-using namespace std::literals::string_view_literals;
-
-template <typename Context> class OutputFile;
-
-inline char *output_tmpfile;
-inline thread_local bool opt_demangle;
-
-inline u8 *output_buffer_start = nullptr;
-inline u8 *output_buffer_end = nullptr;
-
-inline std::string mold_version;
-extern std::string mold_version_string;
-extern std::string mold_git_hash;
-
-std::string errno_string();
-std::string get_self_path();
-void cleanup();
-void install_signal_handler();
-i64 get_default_thread_count();
-
-static u64 combine_hash(u64 a, u64 b) {
-  return a ^ (b + 0x9e3779b9 + (a << 6) + (a >> 2));
-}
-
-//
-// Error output
-//
-
-template <typename Context>
-class SyncOut {
-public:
-  SyncOut(Context &ctx, std::ostream &out = std::cout) : out(out) {
-    opt_demangle = ctx.arg.demangle;
-  }
-
-  ~SyncOut() {
-    std::scoped_lock lock(mu);
-    out << ss.str() << "\n";
-  }
-
-  template <class T> SyncOut &operator<<(T &&val) {
-    ss << std::forward<T>(val);
-    return *this;
-  }
-
-  static inline std::mutex mu;
-
-private:
-  std::ostream &out;
-  std::stringstream ss;
-};
-
-template <typename Context>
-static std::string add_color(Context &ctx, std::string msg) {
-  if (ctx.arg.color_diagnostics)
-    return "mold: \033[0;1;31m" + msg + ":\033[0m ";
-  return "mold: " + msg + ": ";
-}
-
-template <typename Context>
-class Fatal {
-public:
-  Fatal(Context &ctx) : out(ctx, std::cerr) {
-    out << add_color(ctx, "fatal");
-  }
-
-  [[noreturn]] ~Fatal() {
-    out.~SyncOut();
-    cleanup();
-    _exit(1);
-  }
-
-  template <class T> Fatal &operator<<(T &&val) {
-    out << std::forward<T>(val);
-    return *this;
-  }
-
-private:
-  SyncOut<Context> out;
-};
-
-template <typename Context>
-class Error {
-public:
-  Error(Context &ctx) : out(ctx, std::cerr) {
-    if (ctx.arg.noinhibit_exec) {
-      out << add_color(ctx, "warning");
-    } else {
-      out << add_color(ctx, "error");
-      ctx.has_error = true;
-    }
-  }
-
-  template <class T> Error &operator<<(T &&val) {
-    out << std::forward<T>(val);
-    return *this;
-  }
-
-private:
-  SyncOut<Context> out;
-};
-
-template <typename Context>
-class Warn {
-public:
-  Warn(Context &ctx) : out(ctx, std::cerr) {
-    if (ctx.arg.fatal_warnings) {
-      out << add_color(ctx, "error");
-      ctx.has_error = true;
-    } else {
-      out << add_color(ctx, "warning");
-    }
-  }
-
-  template <class T> Warn &operator<<(T &&val) {
-    out << std::forward<T>(val);
-    return *this;
-  }
-
-private:
-  SyncOut<Context> out;
-};
-
-//
-// Atomics
-//
-
-// This is the same as std::atomic except that the default memory
-// order is relaxed instead of sequential consistency.
-template <typename T>
-struct Atomic : std::atomic<T> {
-  static constexpr std::memory_order relaxed = std::memory_order_relaxed;
-
-  using std::atomic<T>::atomic;
-
-  void operator=(T val) { store(val); }
-  operator T() const { return load(); }
-
-  void store(T val, std::memory_order order = relaxed) {
-    std::atomic<T>::store(val, order);
-  }
-
-  T load(std::memory_order order = relaxed) const {
-    return std::atomic<T>::load(order);
-  }
-
-  T exchange(T val, std::memory_order order = relaxed) {
-    return std::atomic<T>::exchange(val, order);
-  }
-
-  T operator|=(T val) { return std::atomic<T>::fetch_or(val, relaxed); }
-
-  bool test_and_set() {
-    // A relaxed load + branch (assuming miss) takes only around 20 cycles,
-    // while an atomic RMW can easily take hundreds on x86. We note that it's
-    // common that another thread beat us in marking, so doing an optimistic
-    // early test tends to improve performance in the ~20% ballpark.
-    return load() || exchange(true);
-  }
-};
-
-//
-// Bit vector
-//
-
-class BitVector {
-public:
-  BitVector() = default;
-  BitVector(u32 size) : vec((size + 7) / 8) {}
-
-  void resize(u32 size) { vec.resize((size + 7) / 8); }
-  bool get(u32 idx) const { return vec[idx / 8] & (1 << (idx % 8)); }
-  void set(u32 idx) { vec[idx / 8] |= 1 << (idx % 8); }
-
-private:
-  std::vector<u8> vec;
-};
-
-//
-// Utility functions
-//
-
-// Some C++ libraries haven't implemented std::has_single_bit yet.
-inline bool has_single_bit(u64 val) {
-  return std::popcount(val) == 1;
-}
-
-// Some C++ libraries haven't implemented std::bit_ceil yet.
-inline u64 bit_ceil(u64 val) {
-  if (has_single_bit(val))
-    return val;
-  return 1LL << (64 - std::countl_zero(val));
-}
-
-inline u64 align_to(u64 val, u64 align) {
-  if (align == 0)
-    return val;
-  assert(has_single_bit(align));
-  return (val + align - 1) & ~(align - 1);
-}
-
-inline u64 align_down(u64 val, u64 align) {
-  assert(has_single_bit(align));
-  return val & ~(align - 1);
-}
-
-inline u64 bit(u64 val, i64 pos) {
-  return (val >> pos) & 1;
-};
-
-// Returns [hi:lo] bits of val.
-inline u64 bits(u64 val, u64 hi, u64 lo) {
-  return (val >> lo) & ((1LL << (hi - lo + 1)) - 1);
-}
-
-inline i64 sign_extend(u64 val, i64 size) {
-  return (i64)(val << (63 - size)) >> (63 - size);
-};
-
-template <typename T, typename Compare = std::less<T>>
-void update_minimum(std::atomic<T> &atomic, u64 new_val, Compare cmp = {}) {
-  T old_val = atomic.load(std::memory_order_relaxed);
-  while (cmp(new_val, old_val) &&
-         !atomic.compare_exchange_weak(old_val, new_val,
-                                       std::memory_order_relaxed));
-}
-
-template <typename T, typename Compare = std::less<T>>
-void update_maximum(std::atomic<T> &atomic, u64 new_val, Compare cmp = {}) {
-  T old_val = atomic.load(std::memory_order_relaxed);
-  while (cmp(old_val, new_val) &&
-         !atomic.compare_exchange_weak(old_val, new_val,
-                                       std::memory_order_relaxed));
-}
-
-template <typename T, typename U>
-inline void append(std::vector<T> &vec1, std::vector<U> vec2) {
-  vec1.insert(vec1.end(), vec2.begin(), vec2.end());
-}
-
-template <typename T>
-inline std::vector<T> flatten(std::vector<std::vector<T>> &vec) {
-  std::vector<T> ret;
-  for (std::vector<T> &v : vec)
-    append(ret, v);
-  return ret;
-}
-
-template <typename T>
-inline void sort(T &vec) {
-  std::stable_sort(vec.begin(), vec.end());
-}
-
-template <typename T, typename U>
-inline void sort(T &vec, U less) {
-  std::stable_sort(vec.begin(), vec.end(), less);
-}
-
-template <typename T>
-inline void remove_duplicates(std::vector<T> &vec) {
-  vec.erase(std::unique(vec.begin(), vec.end()), vec.end());
-}
-
-inline i64 write_string(void *buf, std::string_view str) {
-  memcpy(buf, str.data(), str.size());
-  *((u8 *)buf + str.size()) = '\0';
-  return str.size() + 1;
-}
-
-template <typename T>
-inline i64 write_vector(void *buf, const std::vector<T> &vec) {
-  i64 sz = vec.size() * sizeof(T);
-  memcpy(buf, vec.data(), sz);
-  return sz;
-}
-
-inline void encode_uleb(std::vector<u8> &vec, u64 val) {
-  do {
-    u8 byte = val & 0x7f;
-    val >>= 7;
-    vec.push_back(val ? (byte | 0x80) : byte);
-  } while (val);
-}
-
-inline void encode_sleb(std::vector<u8> &vec, i64 val) {
-  for (;;) {
-    u8 byte = val & 0x7f;
-    val >>= 7;
-
-    bool neg = (byte & 0x40);
-    if ((val == 0 && !neg) || (val == -1 && neg)) {
-      vec.push_back(byte);
-      break;
-    }
-    vec.push_back(byte | 0x80);
-  }
-}
-
-inline i64 write_uleb(u8 *buf, u64 val) {
-  i64 i = 0;
-  do {
-    u8 byte = val & 0x7f;
-    val >>= 7;
-    buf[i++] = val ? (byte | 0x80) : byte;
-  } while (val);
-  return i;
-}
-
-inline u64 read_uleb(u8 *&buf) {
-  u64 val = 0;
-  u8 shift = 0;
-  u8 byte;
-  do {
-    byte = *buf++;
-    val |= (byte & 0x7f) << shift;
-    shift += 7;
-  } while (byte & 0x80);
-  return val;
-}
-
-inline u64 read_uleb(u8 const*&buf) {
-  return read_uleb(const_cast<u8 *&>(buf));
-}
-
-inline u64 read_uleb(std::string_view &str) {
-  u8 *start = (u8 *)&str[0];
-  u8 *ptr = start;
-  u64 val = read_uleb(ptr);
-  str = str.substr(ptr - start);
-  return val;
-}
-
-inline i64 uleb_size(u64 val) {
-#if __GNUC__
-#pragma GCC unroll 8
-#endif
-  for (int i = 1; i < 9; i++)
-    if (val < (1LL << (7 * i)))
-      return i;
-  return 9;
-}
-
-template <typename Context>
-std::string_view save_string(Context &ctx, const std::string &str) {
-  u8 *buf = new u8[str.size() + 1];
-  memcpy(buf, str.data(), str.size());
-  buf[str.size()] = '\0';
-  ctx.string_pool.push_back(std::unique_ptr<u8[]>(buf));
-  return {(char *)buf, str.size()};
-}
-
-inline bool remove_prefix(std::string_view &s, std::string_view prefix) {
-  if (s.starts_with(prefix)) {
-    s = s.substr(prefix.size());
-    return true;
-  }
-  return false;
-}
-
-//
-// Concurrent Map
-//
-
-// This is an implementation of a fast concurrent hash map. Unlike
-// ordinary hash tables, this impl just aborts if it becomes full.
-// So you need to give a correct estimation of the final size before
-// using it. We use this hash map to uniquify pieces of data in
-// mergeable sections.
-template <typename T>
-class ConcurrentMap {
-public:
-  ConcurrentMap() {}
-
-  ConcurrentMap(i64 nbuckets) {
-    resize(nbuckets);
-  }
-
-  ~ConcurrentMap() {
-    if (keys) {
-      free((void *)keys);
-      free((void *)key_sizes);
-      free((void *)values);
-    }
-  }
-
-  void resize(i64 nbuckets) {
-    this->~ConcurrentMap();
-
-    nbuckets = std::max<i64>(MIN_NBUCKETS, bit_ceil(nbuckets));
-
-    this->nbuckets = nbuckets;
-    keys = (std::atomic<const char *> *)calloc(nbuckets, sizeof(char *));
-    key_sizes = (u32 *)malloc(nbuckets * sizeof(u32));
-    values = (T *)malloc(nbuckets * sizeof(T));
-  }
-
-  std::pair<T *, bool> insert(std::string_view key, u64 hash, const T &val) {
-    if (!keys)
-      return {nullptr, false};
-
-    assert(has_single_bit(nbuckets));
-    i64 idx = hash & (nbuckets - 1);
-    i64 retry = 0;
-
-    while (retry < MAX_RETRY) {
-      const char *ptr = keys[idx].load(std::memory_order_acquire);
-      if (ptr == marker) {
-        pause();
-        continue;
-      }
-
-      if (ptr == nullptr) {
-        if (!keys[idx].compare_exchange_weak(ptr, marker,
-                                             std::memory_order_acquire))
-          continue;
-        new (values + idx) T(val);
-        key_sizes[idx] = key.size();
-        keys[idx].store(key.data(), std::memory_order_release);
-        return {values + idx, true};
-      }
-
-      if (key.size() == key_sizes[idx] &&
-          memcmp(ptr, key.data(), key_sizes[idx]) == 0)
-        return {values + idx, false};
-
-      u64 mask = nbuckets / NUM_SHARDS - 1;
-      idx = (idx & ~mask) | ((idx + 1) & mask);
-      retry++;
-    }
-
-    assert(false && "ConcurrentMap is full");
-    return {nullptr, false};
-  }
-
-  const char *get_key(i64 idx) {
-    return keys[idx].load(std::memory_order_relaxed);
-  }
-
-  static constexpr i64 MIN_NBUCKETS = 2048;
-  static constexpr i64 NUM_SHARDS = 16;
-  static constexpr i64 MAX_RETRY = 128;
-
-  i64 nbuckets = 0;
-  u32 *key_sizes = nullptr;
-  T *values = nullptr;
-
-private:
-  static void pause() {
-#if defined(__x86_64__)
-    asm volatile("pause");
-#elif defined(__aarch64__)
-    asm volatile("yield");
-#endif
-  }
-
-private:
-  std::atomic<const char *> *keys = nullptr;
-  static constexpr const char *marker = "marker";
-};
-
-//
-// output-file.h
-//
-
-template <typename Context>
-class OutputFile {
-public:
-  static std::unique_ptr<OutputFile<Context>>
-  open(Context &ctx, std::string path, i64 filesize, i64 perm);
-
-  virtual void close(Context &ctx) = 0;
-  virtual ~OutputFile() = default;
-
-  u8 *buf = nullptr;
-  std::string path;
-  i64 filesize;
-  bool is_mmapped;
-  bool is_unmapped = false;
-
-protected:
-  OutputFile(std::string path, i64 filesize, bool is_mmapped)
-    : path(path), filesize(filesize), is_mmapped(is_mmapped) {}
-};
-
-//
-// hyperloglog.cc
-//
-
-class HyperLogLog {
-public:
-  HyperLogLog() : buckets(NBUCKETS) {}
-
-  void insert(u32 hash) {
-    update_maximum(buckets[hash & (NBUCKETS - 1)], std::countl_zero(hash) + 1);
-  }
-
-  i64 get_cardinality() const;
-
-  void merge(const HyperLogLog &other) {
-    for (i64 i = 0; i < NBUCKETS; i++)
-      update_maximum(buckets[i], other.buckets[i]);
-  }
-
-private:
-  static constexpr i64 NBUCKETS = 2048;
-  static constexpr double ALPHA = 0.79402;
-
-  std::vector<std::atomic_uint8_t> buckets;
-};
-
-//
-// glob.cc
-//
-
-class Glob {
-  typedef enum { STRING, STAR, QUESTION, BRACKET } Kind;
-
-  struct Element {
-    Element(Kind k) : kind(k) {}
-    Kind kind;
-    std::string str;
-    std::bitset<256> bitset;
-  };
-
-public:
-  static std::optional<Glob> compile(std::string_view pat);
-  bool match(std::string_view str);
-
-private:
-  Glob(std::vector<Element> &&vec) : elements(vec) {}
-  static bool do_match(std::string_view str, std::span<Element> elements);
-
-  std::vector<Element> elements;
-};
-
-//
-// multi-glob.cc
-//
-
-class MultiGlob {
-public:
-  bool add(std::string_view pat, u32 val);
-  bool empty() const { return strings.empty(); }
-  std::optional<u32> find(std::string_view str);
-
-private:
-  struct TrieNode {
-    u32 value = -1;
-    TrieNode *suffix_link = nullptr;
-    std::unique_ptr<TrieNode> children[256];
-  };
-
-  void compile();
-  void fix_suffix_links(TrieNode &node);
-  void fix_values();
-
-  std::vector<std::string> strings;
-  std::unique_ptr<TrieNode> root;
-  std::vector<std::pair<Glob, u32>> globs;
-  std::once_flag once;
-  bool is_compiled = false;
-};
-
-//
-// uuid.cc
-//
-
-std::array<u8, 16> get_uuid_v4();
-
-//
-// filepath.cc
-//
-
-template <typename T>
-std::filesystem::path filepath(const T &path) {
-  return {path, std::filesystem::path::format::generic_format};
-}
-
-std::string get_realpath(std::string_view path);
-std::string path_clean(std::string_view path);
-std::filesystem::path to_abs_path(std::filesystem::path path);
-
-//
-// demangle.cc
-//
-
-std::string_view demangle(std::string_view name);
-std::optional<std::string_view> cpp_demangle(std::string_view name);
-
-//
-// compress.cc
-//
-
-class Compressor {
-public:
-  virtual void write_to(u8 *buf) = 0;
-  virtual ~Compressor() {}
-  i64 compressed_size = 0;
-};
-
-class ZlibCompressor : public Compressor {
-public:
-  ZlibCompressor(u8 *buf, i64 size);
-  void write_to(u8 *buf) override;
-
-private:
-  std::vector<std::vector<u8>> shards;
-  u64 checksum = 0;
-};
-
-class ZstdCompressor : public Compressor {
-public:
-  ZstdCompressor(u8 *buf, i64 size);
-  void write_to(u8 *buf) override;
-
-private:
-  std::vector<std::vector<u8>> shards;
-};
-
-//
-// perf.cc
-//
-
-// Counter is used to collect statistics numbers.
-class Counter {
-public:
-  Counter(std::string_view name, i64 value = 0) : name(name), values(value) {
-    static std::mutex mu;
-    std::scoped_lock lock(mu);
-    instances.push_back(this);
-  }
-
-  Counter &operator++(int) {
-    if (enabled) [[unlikely]]
-      values.local()++;
-    return *this;
-  }
-
-  Counter &operator+=(int delta) {
-    if (enabled) [[unlikely]]
-      values.local() += delta;
-    return *this;
-  }
-
-  static void print();
-
-  static inline bool enabled = false;
-
-private:
-  i64 get_value();
-
-  std::string_view name;
-  tbb::enumerable_thread_specific<i64> values;
-
-  static inline std::vector<Counter *> instances;
-};
-
-// Timer and TimeRecord records elapsed time (wall clock time)
-// used by each pass of the linker.
-struct TimerRecord {
-  TimerRecord(std::string name, TimerRecord *parent = nullptr);
-  void stop();
-
-  std::string name;
-  TimerRecord *parent;
-  tbb::concurrent_vector<TimerRecord *> children;
-  i64 start;
-  i64 end;
-  i64 user;
-  i64 sys;
-  bool stopped = false;
-};
-
-void
-print_timer_records(tbb::concurrent_vector<std::unique_ptr<TimerRecord>> &);
-
-template <typename Context>
-class Timer {
-public:
-  Timer(Context &ctx, std::string name, Timer *parent = nullptr) {
-    record = new TimerRecord(name, parent ? parent->record : nullptr);
-    ctx.timer_records.push_back(std::unique_ptr<TimerRecord>(record));
-  }
-
-  Timer(const Timer &) = delete;
-
-  ~Timer() {
-    record->stop();
-  }
-
-  void stop() {
-    record->stop();
-  }
-
-private:
-  TimerRecord *record;
-};
-
-//
-// tar.cc
-//
-
-// TarFile is a class to create a tar file.
-//
-// If you pass `--repro` to mold, mold collects all input files and
-// put them into `<output-file-path>.repro.tar`, so that it is easy to
-// run the same command with the same command line arguments.
-class TarWriter {
-public:
-  static std::unique_ptr<TarWriter>
-  open(std::string output_path, std::string basedir);
-
-  ~TarWriter();
-  void append(std::string path, std::string_view data);
-
-private:
-  static constexpr i64 BLOCK_SIZE = 512;
-
-  TarWriter(FILE *out, std::string basedir) : out(out), basedir(basedir) {}
-
-  FILE *out = nullptr;
-  std::string basedir;
-};
-
-//
-// Memory-mapped file
-//
-
-// MappedFile represents an mmap'ed input file.
-// mold uses mmap-IO only.
-template <typename Context>
-class MappedFile {
-public:
-  static MappedFile *open(Context &ctx, std::string path);
-  static MappedFile *must_open(Context &ctx, std::string path);
-
-  ~MappedFile() { unmap(); }
-  void unmap();
-
-  MappedFile *slice(Context &ctx, std::string name, u64 start, u64 size);
-
-  std::string_view get_contents() {
-    return std::string_view((char *)data, size);
-  }
-
-  i64 get_offset() const {
-    return parent ? (data - parent->data + parent->get_offset()) : 0;
-  }
-
-  // Returns a string that uniquely identify a file that is possibly
-  // in an archive.
-  std::string get_identifier() const {
-    if (parent) {
-      // We use the file offset within an archive as an identifier
-      // because archive members may have the same name.
-      return parent->name + ":" + std::to_string(get_offset());
-    }
-
-    if (thin_parent) {
-      // If this is a thin archive member, the filename part is
-      // guaranteed to be unique.
-      return thin_parent->name + ":" + name;
-    }
-    return name;
-  }
-
-  std::string name;
-  u8 *data = nullptr;
-  i64 size = 0;
-  i64 mtime = 0;
-  bool given_fullpath = true;
-  MappedFile *parent = nullptr;
-  MappedFile *thin_parent = nullptr;
-  int fd = -1;
-#ifdef _WIN32
-  HANDLE file_handle = INVALID_HANDLE_VALUE;
-#endif
-};
-
-template <typename Context>
-MappedFile<Context> *MappedFile<Context>::open(Context &ctx, std::string path) {
-  if (path.starts_with('/') && !ctx.arg.chroot.empty())
-    path = ctx.arg.chroot + "/" + path_clean(path);
-
-  i64 fd;
-#ifdef _WIN32
-    fd = ::_open(path.c_str(), O_RDONLY);
-#else
-    fd = ::open(path.c_str(), O_RDONLY);
-#endif
-
-  if (fd == -1)
-    return nullptr;
-
-  struct stat st;
-  if (fstat(fd, &st) == -1)
-    Fatal(ctx) << path << ": fstat failed: " << errno_string();
-
-  MappedFile *mf = new MappedFile;
-  ctx.mf_pool.push_back(std::unique_ptr<MappedFile>(mf));
-
-  mf->name = path;
-  mf->size = st.st_size;
-
-#ifdef _WIN32
-    mf->mtime = st.st_mtime;
-#elif defined(__APPLE__)
-    mf->mtime = (u64)st.st_mtimespec.tv_sec * 1'000'000'000 +
-                st.st_mtimespec.tv_nsec;
-#else
-    mf->mtime = (u64)st.st_mtim.tv_sec * 1'000'000'000 + st.st_mtim.tv_nsec;
-#endif
-
-  if (st.st_size > 0) {
-#ifdef _WIN32
-    HANDLE handle = CreateFileMapping((HANDLE)_get_osfhandle(fd),
-                                      nullptr, PAGE_READWRITE, 0,
-                                      st.st_size, nullptr);
-    if (!handle)
-      Fatal(ctx) << path << ": CreateFileMapping failed: " << GetLastError();
-    mf->file_handle = handle;
-    mf->data = (u8 *)MapViewOfFile(handle, FILE_MAP_ALL_ACCESS, 0, 0, st.st_size);
-    if (!mf->data)
-      Fatal(ctx) << path << ": MapViewOfFile failed: " << GetLastError();
-#else
-    mf->data = (u8 *)mmap(nullptr, st.st_size, PROT_READ | PROT_WRITE,
-                          MAP_PRIVATE, fd, 0);
-    if (mf->data == MAP_FAILED)
-      Fatal(ctx) << path << ": mmap failed: " << errno_string();
-#endif
-    }
-
-  close(fd);
-  return mf;
-}
-
-template <typename Context>
-MappedFile<Context> *
-MappedFile<Context>::must_open(Context &ctx, std::string path) {
-  if (MappedFile *mf = MappedFile::open(ctx, path))
-    return mf;
-  Fatal(ctx) << "cannot open " << path << ": " << errno_string();
-}
-
-template <typename Context>
-MappedFile<Context> *
-MappedFile<Context>::slice(Context &ctx, std::string name, u64 start, u64 size) {
-  MappedFile *mf = new MappedFile;
-  mf->name = name;
-  mf->data = data + start;
-  mf->size = size;
-  mf->parent = this;
-
-  ctx.mf_pool.push_back(std::unique_ptr<MappedFile>(mf));
-  return mf;
-}
-
-template <typename Context>
-void MappedFile<Context>::unmap() {
-  if (size == 0 || parent || !data)
-    return;
-
-#ifdef _WIN32
-  UnmapViewOfFile(data);
-  if (file_handle != INVALID_HANDLE_VALUE)
-    CloseHandle(file_handle);
-#else
-  munmap(data, size);
-#endif
-
-  data = nullptr;
-}
-
-} // namespace mold

common/config.h.in

@@ -1,3 +0,0 @@
-#define MOLD_VERSION "@mold_VERSION@"
-#define MOLD_LIBDIR "@CMAKE_INSTALL_FULL_LIBDIR@"
-#cmakedefine01 MOLD_IS_SOLD

common/filepath.cc

@@ -1,27 +0,0 @@
-#include "common.h"
-
-#include <filesystem>
-#include <sys/stat.h>
-
-namespace mold {
-
-std::string get_realpath(std::string_view path) {
-  std::error_code ec;
-  std::string ret = std::filesystem::canonical(path, ec).string();
-  return ec ? std::string(path) : ret;
-}
-
-// Removes redundant '/..' or '/.' from a given path.
-// The transformation is done purely by lexical processing.
-// This function does not access file system.
-std::string path_clean(std::string_view path) {
-  return filepath(path).lexically_normal().string();
-}
-
-std::filesystem::path to_abs_path(std::filesystem::path path) {
-  if (path.is_absolute())
-    return path.lexically_normal();
-  return (std::filesystem::current_path() / path).lexically_normal();
-}
-
-} // namespace mold

common/glob.cc

@@ -1,149 +0,0 @@
-#include "common.h"
-
-#include <cstring>
-
-namespace mold {
-
-std::optional<Glob> Glob::compile(std::string_view pat) {
-  std::vector<Element> vec;
-
-  while (!pat.empty()) {
-    u8 c = pat[0];
-    pat = pat.substr(1);
-
-    switch (c) {
-    case '[': {
-      // Here are a few bracket pattern examples:
-      //
-      // [abc]: a, b or c
-      // [$\]!]: $, ] or !
-      // [a-czg-i]: a, b, c, z, g, h, or i
-      // [^a-z]: Any character except lowercase letters
-      vec.push_back({BRACKET});
-      std::bitset<256> &bitset = vec.back().bitset;
-
-      bool negate = false;
-      if (!pat.empty() && pat[0] == '^') {
-        negate = true;
-        pat = pat.substr(1);
-      }
-
-      bool closed = false;
-
-      while (!pat.empty()) {
-        if (pat[0] == ']') {
-          pat = pat.substr(1);
-          closed = true;
-          break;
-        }
-
-        if (pat[0] == '\\') {
-          pat = pat.substr(1);
-          if (pat.empty())
-            return {};
-        }
-
-        if (pat.size() >= 3 && pat[1] == '-') {
-          u8 start = pat[0];
-          u8 end = pat[2];
-          pat = pat.substr(3);
-
-          if (end == '\\') {
-            if (pat.empty())
-              return {};
-            end = pat[0];
-            pat = pat.substr(1);
-          }
-
-          if (end < start)
-            return {};
-
-          for (i64 i = start; i <= end; i++)
-            bitset[i] = true;
-        } else {
-          bitset[(u8)pat[0]] = true;
-          pat = pat.substr(1);
-        }
-      }
-
-      if (!closed)
-        return {};
-
-      if (negate)
-        bitset.flip();
-      break;
-    }
-    case '?':
-      vec.push_back({QUESTION});
-      break;
-    case '*':
-      vec.push_back({STAR});
-      break;
-    default:
-      if (vec.empty() || vec.back().kind != STRING)
-        vec.push_back({STRING});
-      vec.back().str += c;
-      break;
-    }
-  }
-
-  return {Glob{std::move(vec)}};
-}
-
-bool Glob::match(std::string_view str) {
-  return do_match(str, elements);
-}
-
-bool Glob::do_match(std::string_view str, std::span<Element> elements) {
-  while (!elements.empty()) {
-    Element &e = elements[0];
-    elements = elements.subspan(1);
-
-    switch (e.kind) {
-    case STRING:
-      if (str.empty() || !str.starts_with(e.str))
-        return false;
-      str = str.substr(e.str.size());
-      break;
-    case STAR:
-      if (elements.empty())
-        return true;
-
-      // Patterns like "*foo*bar*" should be much more common than more
-      // complex ones like "*foo*[abc]*" or "*foo**?bar*", so we optimize
-      // the former case here.
-      if (elements[0].kind == STRING) {
-        for (;;) {
-          size_t pos = str.find(elements[0].str);
-          if (pos == str.npos)
-            break;
-          if (do_match(str.substr(pos + elements[0].str.size()),
-                       elements.subspan(1)))
-            return true;
-          str = str.substr(pos + 1);
-        }
-        return false;
-      }
-
-      // Other cases are handled here.
-      for (i64 j = 0; j < str.size(); j++)
-        if (do_match(str.substr(j), elements))
-          return true;
-      return false;
-    case QUESTION:
-      if (str.empty())
-        return false;
-      str = str.substr(1);
-      break;
-    case BRACKET:
-      if (str.empty() || !e.bitset[str[0]])
-        return false;
-      str = str.substr(1);
-      break;
-    }
-  }
-
-  return str.empty();
-}
-
-} // namespace mold

common/integers.h

@@ -1,221 +0,0 @@
-// This file defines integral types for file input/output. We need to use
-// these types instead of the plain integers (such as uint32_t or int32_t)
-// when reading from/writing to an mmap'ed file area for the following
-// reasons:
-//
-// 1. mold is always a cross linker and should not depend on what host it
-//    is running on. Users should be able to run mold on a big-endian
-//    SPARC machine to create a little-endian RV64 binary, for example.
-//
-// 2. Even though data members in all ELF data strucutres are naturally
-//    aligned, they are not guaranteed to be aligned on memory. Because
-//    archive file (.a file) aligns each member only to a 2 byte boundary,
-//    anything larger than 2 bytes may be unaligned in an mmap'ed memory.
-//    Unaligned access is an undefined behavior in C/C++, so we shouldn't
-//    cast an arbitrary pointer to a uint32_t, for example, to read a
-//    32-bits value.
-//
-// The data types defined in this file don't depend on host byte order and
-// don't do unaligned access.
-
-#pragma once
-
-#include <bit>
-#include <cstdint>
-#include <cstring>
-
-#if !defined(__LITTLE_ENDIAN__) && !defined(__BIG_ENDIAN__)
-# if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-#  define __LITTLE_ENDIAN__ 1
-# elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
-#  define __BIG_ENDIAN__ 1
-# else
-#  error "unknown host byte order"
-# endif
-#endif
-
-namespace mold {
-
-typedef uint8_t u8;
-typedef uint16_t u16;
-typedef uint32_t u32;
-typedef uint64_t u64;
-
-typedef int8_t i8;
-typedef int16_t i16;
-typedef int32_t i32;
-typedef int64_t i64;
-
-template <typename T>
-static inline T bswap(T val) {
-  switch (sizeof(T)) {
-  case 2:  return __builtin_bswap16(val);
-  case 4:  return __builtin_bswap32(val);
-  case 8:  return __builtin_bswap64(val);
-  default: __builtin_unreachable();
-  }
-}
-
-template <typename T, int SIZE = sizeof(T)>
-class LittleEndian {
-public:
-  LittleEndian() = default;
-  LittleEndian(T x) { *this = x; }
-
-  operator T() const {
-    if constexpr (sizeof(T) == SIZE) {
-      T x;
-      memcpy(&x, val, sizeof(T));
-      if constexpr (std::endian::native == std::endian::big)
-        x = bswap(x);
-      return x;
-    } else {
-      static_assert(SIZE == 3);
-      return (val[2] << 16) | (val[1] << 8) | val[0];
-    }
-  }
-
-  LittleEndian &operator=(T x) {
-    if constexpr (sizeof(T) == SIZE) {
-      if constexpr (std::endian::native == std::endian::big)
-        x = bswap(x);
-      memcpy(val, &x, sizeof(T));
-    } else {
-      static_assert(SIZE == 3);
-      val[2] = x >> 16;
-      val[1] = x >> 8;
-      val[0] = x;
-    }
-    return *this;
-  }
-
-  LittleEndian &operator++() {
-    return *this = *this + 1;
-  }
-
-  LittleEndian operator++(int) {
-    T ret = *this;
-    *this = *this + 1;
-    return ret;
-  }
-
-  LittleEndian &operator--() {
-    return *this = *this - 1;
-  }
-
-  LittleEndian operator--(int) {
-    T ret = *this;
-    *this = *this - 1;
-    return ret;
-  }
-
-  LittleEndian &operator+=(T x) {
-    return *this = *this + x;
-  }
-
-  LittleEndian &operator-=(T x) {
-    return *this = *this - x;
-  }
-
-  LittleEndian &operator&=(T x) {
-    return *this = *this & x;
-  }
-
-  LittleEndian &operator|=(T x) {
-    return *this = *this | x;
-  }
-
-private:
-  u8 val[SIZE];
-};
-
-using il16 = LittleEndian<i16>;
-using il32 = LittleEndian<i32>;
-using il64 = LittleEndian<i64>;
-using ul16 = LittleEndian<u16>;
-using ul24 = LittleEndian<u32, 3>;
-using ul32 = LittleEndian<u32>;
-using ul64 = LittleEndian<u64>;
-
-template <typename T, int SIZE = sizeof(T)>
-class BigEndian {
-public:
-  BigEndian() = default;
-  BigEndian(T x) { *this = x; }
-
-  operator T() const {
-    if constexpr (sizeof(T) == SIZE) {
-      T x;
-      memcpy(&x, val, sizeof(T));
-      if constexpr (std::endian::native == std::endian::little)
-        x = bswap(x);
-      return x;
-    } else {
-      static_assert(SIZE == 3);
-      return (val[0] << 16) | (val[1] << 8) | val[2];
-    }
-  }
-
-  BigEndian &operator=(T x) {
-    if constexpr (sizeof(T) == SIZE) {
-      if constexpr (std::endian::native == std::endian::little)
-        x = bswap(x);
-      memcpy(val, &x, sizeof(T));
-    } else {
-      static_assert(SIZE == 3);
-      val[0] = x >> 16;
-      val[1] = x >> 8;
-      val[2] = x;
-    }
-    return *this;
-  }
-
-  BigEndian &operator++() {
-    return *this = *this + 1;
-  }
-
-  BigEndian operator++(int) {
-    T ret = *this;
-    *this = *this + 1;
-    return ret;
-  }
-
-  BigEndian &operator--() {
-    return *this = *this - 1;
-  }
-
-  BigEndian operator--(int) {
-    T ret = *this;
-    *this = *this - 1;
-    return ret;
-  }
-
-  BigEndian &operator+=(T x) {
-    return *this = *this + x;
-  }
-
-  BigEndian &operator-=(T x) {
-    return *this = *this - x;
-  }
-
-  BigEndian &operator&=(T x) {
-    return *this = *this & x;
-  }
-
-  BigEndian &operator|=(T x) {
-    return *this = *this | x;
-  }
-
-private:
-  u8 val[SIZE];
-};
-
-using ib16 = BigEndian<i16>;
-using ib32 = BigEndian<i32>;
-using ib64 = BigEndian<i64>;
-using ub16 = BigEndian<u16>;
-using ub24 = BigEndian<u32, 3>;
-using ub32 = BigEndian<u32>;
-using ub64 = BigEndian<u64>;
-
-} // namespace mold

common/main.cc

@@ -1,156 +0,0 @@
-#include "common.h"
-#include "config.h"
-
-#include <cstring>
-#include <filesystem>
-#include <signal.h>
-#include <tbb/global_control.h>
-
-#ifdef USE_SYSTEM_MIMALLOC
-#include <mimalloc-new-delete.h>
-#endif
-
-#ifdef __FreeBSD__
-# include <sys/sysctl.h>
-# include <unistd.h>
-#endif
-
-namespace mold {
-
-std::string mold_version_string = MOLD_VERSION;
-
-namespace elf {
-int main(int argc, char **argv);
-}
-
-namespace macho {
-int main(int argc, char **argv);
-}
-
-static std::string get_mold_version() {
-  std::string name = MOLD_IS_SOLD ? "mold (sold) " : "mold ";
-  if (mold_git_hash.empty())
-    return name + MOLD_VERSION + " (compatible with GNU ld)";
-  return name + MOLD_VERSION + " (" + mold_git_hash + "; compatible with GNU ld)";
-}
-
-void cleanup() {
-  if (output_tmpfile)
-    unlink(output_tmpfile);
-}
-
-std::string errno_string() {
-  // strerror is not thread-safe, so guard it with a lock.
-  static std::mutex mu;
-  std::scoped_lock lock(mu);
-  return strerror(errno);
-}
-
-// Returns the path of the mold executable itself
-std::string get_self_path() {
-#ifdef __FreeBSD__
-  // /proc may not be mounted on FreeBSD. The proper way to get the
-  // current executable's path is to use sysctl(2).
-  int mib[4];
-  mib[0] = CTL_KERN;
-  mib[1] = KERN_PROC;
-  mib[2] = KERN_PROC_PATHNAME;
-  mib[3] = -1;
-
-  size_t size;
-  sysctl(mib, 4, NULL, &size, NULL, 0);
-
-  std::string path;
-  path.resize(size);
-  sysctl(mib, 4, path.data(), &size, NULL, 0);
-  return path;
-#else
-  return std::filesystem::read_symlink("/proc/self/exe").string();
-#endif
-}
-
-// mold mmap's an output file, and the mmap succeeds even if there's
-// no enough space left on the filesystem. The actual disk blocks are
-// not allocated on the mmap call but when the program writes to it
-// for the first time.
-//
-// If a disk becomes full as a result of a write to an mmap'ed memory
-// region, the failure of the write is reported as a SIGBUS or structured
-// exeption with code EXCEPTION_IN_PAGE_ERROR on Windows. This
-// signal handler catches that signal and prints out a user-friendly
-// error message. Without this, it is very hard to realize that the
-// disk might be full.
-#ifdef _WIN32
-
-static LONG WINAPI vectored_handler(_EXCEPTION_POINTERS *exception_info) {
-  static std::mutex mu;
-  std::scoped_lock lock{mu};
-
-  PEXCEPTION_RECORD exception_record = exception_info->ExceptionRecord;
-  ULONG_PTR *exception_information = exception_record->ExceptionInformation;
-  if (exception_record->ExceptionCode == EXCEPTION_IN_PAGE_ERROR &&
-      (ULONG_PTR)output_buffer_start <= exception_information[1] &&
-      exception_information[1] < (ULONG_PTR)output_buffer_end) {
-
-    const char msg[] = "mold: failed to write to an output file. Disk full?\n";
-    (void)!write(_fileno(stderr), msg, sizeof(msg) - 1);
-  }
-
-  cleanup();
-  _exit(1);
-}
-
-void install_signal_handler() {
-  AddVectoredExceptionHandler(0, vectored_handler);
-}
-
-#else
-
-static void sighandler(int signo, siginfo_t *info, void *ucontext) {
-  static std::mutex mu;
-  std::scoped_lock lock{mu};
-
-  if ((signo == SIGSEGV || signo == SIGBUS) &&
-      output_buffer_start <= info->si_addr &&
-      info->si_addr < output_buffer_end) {
-    const char msg[] = "mold: failed to write to an output file. Disk full?\n";
-    (void)!write(STDERR_FILENO, msg, sizeof(msg) - 1);
-  }
-
-  cleanup();
-  _exit(1);
-}
-
-void install_signal_handler() {
-  struct sigaction action;
-  action.sa_sigaction = sighandler;
-  sigemptyset(&action.sa_mask);
-  action.sa_flags = SA_SIGINFO;
-
-  sigaction(SIGINT, &action, NULL);
-  sigaction(SIGTERM, &action, NULL);
-  sigaction(SIGBUS, &action, NULL);
-}
-
-#endif
-
-i64 get_default_thread_count() {
-  // mold doesn't scale well above 32 threads.
-  int n = tbb::global_control::active_value(
-    tbb::global_control::max_allowed_parallelism);
-  return std::min(n, 32);
-}
-
-} // namespace mold
-
-int main(int argc, char **argv) {
-  mold::mold_version = mold::get_mold_version();
-
-#if MOLD_IS_SOLD
-  std::string cmd = mold::filepath(argv[0]).filename().string();
-  if (cmd == "ld64" || cmd == "ld64.mold")
-    return mold::macho::main(argc, argv);
-#endif
-
-  return mold::elf::main(argc, argv);
-}

common/multi-glob.cc

@@ -1,166 +0,0 @@
-// This file implements the Aho-Corasick algorithm to match multiple
-// glob patterns to symbol strings as quickly as possible.
-//
-// Here are some examples of glob patterns:
-//
-//    qt_private_api_tag*
-//    *16QAccessibleCache*
-//    *32QAbstractFileIconProviderPrivate*
-//    *17QPixmapIconEngine*
-//
-// `*` is a wildcard that matches any substring. We sometimes have
-// hundreds of glob patterns and have to match them against millions
-// of symbol strings.
-//
-// Aho-Corasick cannot handle complex patterns such as `*foo*bar*`.
-// We handle such patterns with the Glob class. Glob is relatively
-// slow, but complex patterns are rare in practice, so it should be
-// OK.
-
-#include "common.h"
-
-#include <queue>
-#include <regex>
-
-namespace mold {
-
-std::optional<u32> MultiGlob::find(std::string_view str) {
-  std::call_once(once, [&] { compile(); });
-  u32 val = UINT32_MAX;
-
-  if (root) {
-    // Match against simple glob patterns
-    TrieNode *node = root.get();
-
-    auto walk = [&](u8 c) {
-      for (;;) {
-        if (node->children[c]) {
-          node = node->children[c].get();
-          val = std::min(val, node->value);
-          return;
-        }
-
-        if (!node->suffix_link)
-          return;
-        node = node->suffix_link;
-      }
-    };
-
-    walk('\0');
-    for (u8 c : str)
-      walk(c);
-    walk('\0');
-  }
-
-  // Match against complex glob patterns
-  for (std::pair<Glob, u32> &glob : globs)
-    if (glob.first.match(str))
-      val = std::min(val, glob.second);
-
-  if (val == UINT32_MAX)
-    return {};
-  return val;
-}
-
-static bool is_simple_pattern(std::string_view pat) {
-  static std::regex re(R"(\*?[^*[?]+\*?)", std::regex_constants::optimize);
-  return std::regex_match(pat.begin(), pat.end(), re);
-}
-
-static std::string handle_stars(std::string_view pat) {
-  std::string str(pat);
-
-  // Convert "foo" -> "\0foo\0", "*foo" -> "foo\0", "foo*" -> "\0foo"
-  // and "*foo*" -> "foo". Aho-Corasick can do only substring matching,
-  // so we use \0 as beginning/end-of-string markers.
-  if (str.starts_with('*') && str.ends_with('*'))
-    return str.substr(1, str.size() - 2);
-  if (str.starts_with('*'))
-    return str.substr(1) + "\0"s;
-  if (str.ends_with('*'))
-    return "\0"s + str.substr(0, str.size() - 1);
-  return "\0"s + str + "\0"s;
-}
-
-bool MultiGlob::add(std::string_view pat, u32 val) {
-  assert(!is_compiled);
-  assert(!pat.empty());
-
-  strings.push_back(std::string(pat));
-
-  // Complex glob pattern
-  if (!is_simple_pattern(pat)) {
-    if (std::optional<Glob> glob = Glob::compile(pat)) {
-      globs.push_back({std::move(*glob), val});
-      return true;
-    }
-    return false;
-  }
-
-  // Simple glob pattern
-  if (!root)
-    root.reset(new TrieNode);
-  TrieNode *node = root.get();
-
-  for (u8 c : handle_stars(pat)) {
-    if (!node->children[c])
-      node->children[c].reset(new TrieNode);
-    node = node->children[c].get();
-  }
-
-  node->value = std::min(node->value, val);
-  return true;
-}
-
-void MultiGlob::compile() {
-  is_compiled = true;
-  if (root) {
-    fix_suffix_links(*root);
-    fix_values();
-  }
-}
-
-void MultiGlob::fix_suffix_links(TrieNode &node) {
-  for (i64 i = 0; i < 256; i++) {
-    if (!node.children[i])
-      continue;
-
-    TrieNode &child = *node.children[i];
-
-    TrieNode *cur = node.suffix_link;
-    for (;;) {
-      if (!cur) {
-        child.suffix_link = root.get();
-        break;
-      }
-
-      if (cur->children[i]) {
-        child.suffix_link = cur->children[i].get();
-        break;
-      }
-
-      cur = cur->suffix_link;
-    }
-
-    fix_suffix_links(child);
-  }
-}
-
-void MultiGlob::fix_values() {
-  std::queue<TrieNode *> queue;
-  queue.push(root.get());
-
-  do {
-    TrieNode *node = queue.front();
-    queue.pop();
-
-    for (std::unique_ptr<TrieNode> &child : node->children) {
-      if (!child)
-        continue;
-      child->value = std::min(child->value, child->suffix_link->value);
-      queue.push(child.get());
-    }
-  } while (!queue.empty());
-}
-
-} // namespace mold

common/output-file-unix.h

@@ -1,169 +0,0 @@
-#include "common.h"
-
-#include <fcntl.h>
-#include <filesystem>
-#include <sys/mman.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-
-namespace mold {
-
-inline u32 get_umask() {
-  u32 orig_umask = umask(0);
-  umask(orig_umask);
-  return orig_umask;
-}
-
-template <typename Context>
-static std::pair<i64, char *>
-open_or_create_file(Context &ctx, std::string path, i64 filesize, i64 perm) {
-  std::string tmpl = filepath(path).parent_path() / ".mold-XXXXXX";
-  char *path2 = (char *)save_string(ctx, tmpl).data();
-
-  i64 fd = mkstemp(path2);
-  if (fd == -1)
-    Fatal(ctx) << "cannot open " << path2 <<  ": " << errno_string();
-
-  // Reuse an existing file if exists and writable because on Linux,
-  // writing to an existing file is much faster than creating a fresh
-  // file and writing to it.
-  if (ctx.overwrite_output_file && rename(path.c_str(), path2) == 0) {
-    ::close(fd);
-    fd = ::open(path2, O_RDWR | O_CREAT, perm);
-    if (fd != -1 && !ftruncate(fd, filesize) && !fchmod(fd, perm & ~get_umask()))
-      return {fd, path2};
-
-    unlink(path2);
-    fd = ::open(path2, O_RDWR | O_CREAT, perm);
-    if (fd == -1)
-      Fatal(ctx) << "cannot open " << path2 << ": " << errno_string();
-  }
-
-  if (ftruncate(fd, filesize))
-    Fatal(ctx) << "ftruncate failed: " << errno_string();
-
-  if (fchmod(fd, (perm & ~get_umask())) == -1)
-    Fatal(ctx) << "fchmod failed: " << errno_string();
-  return {fd, path2};
-}
-
-template <typename Context>
-class MemoryMappedOutputFile : public OutputFile<Context> {
-public:
-  MemoryMappedOutputFile(Context &ctx, std::string path, i64 filesize, i64 perm)
-    : OutputFile<Context>(path, filesize, true) {
-    i64 fd;
-    std::tie(fd, output_tmpfile) = open_or_create_file(ctx, path, filesize, perm);
-
-    this->buf = (u8 *)mmap(nullptr, filesize, PROT_READ | PROT_WRITE,
-                           MAP_SHARED, fd, 0);
-    if (this->buf == MAP_FAILED)
-      Fatal(ctx) << path << ": mmap failed: " << errno_string();
-    ::close(fd);
-
-    mold::output_buffer_start = this->buf;
-    mold::output_buffer_end = this->buf + filesize;
-  }
-
-  ~MemoryMappedOutputFile() {
-    if (fd2 != -1)
-      ::close(fd2);
-  }
-
-  void close(Context &ctx) override {
-    Timer t(ctx, "close_file");
-
-    if (!this->is_unmapped)
-      munmap(this->buf, this->filesize);
-
-    // If an output file already exists, open a file and then remove it.
-    // This is the fastest way to unlink a file, as it does not make the
-    // system to immediately release disk blocks occupied by the file.
-    fd2 = ::open(this->path.c_str(), O_RDONLY);
-    if (fd2 != -1)
-      unlink(this->path.c_str());
-
-    if (rename(output_tmpfile, this->path.c_str()) == -1)
-      Fatal(ctx) << this->path << ": rename failed: " << errno_string();
-    output_tmpfile = nullptr;
-  }
-
-private:
-  int fd2 = -1;
-};
-
-template <typename Context>
-class MallocOutputFile : public OutputFile<Context> {
-public:
-  MallocOutputFile(Context &ctx, std::string path, i64 filesize, i64 perm)
-    : OutputFile<Context>(path, filesize, false), perm(perm) {
-    this->buf = (u8 *)mmap(NULL, filesize, PROT_READ | PROT_WRITE,
-                           MAP_SHARED | MAP_ANONYMOUS, -1, 0);
-    if (this->buf == MAP_FAILED)
-      Fatal(ctx) << "mmap failed: " << errno_string();
-  }
-
-  void close(Context &ctx) override {
-    Timer t(ctx, "close_file");
-
-    if (this->path == "-") {
-      fwrite(this->buf, this->filesize, 1, stdout);
-      fclose(stdout);
-      return;
-    }
-
-    i64 fd = ::open(this->path.c_str(), O_RDWR | O_CREAT, perm);
-    if (fd == -1)
-      Fatal(ctx) << "cannot open " << this->path << ": " << errno_string();
-
-    FILE *fp = fdopen(fd, "w");
-    fwrite(this->buf, this->filesize, 1, fp);
-    fclose(fp);
-  }
-
-private:
-  i64 perm;
-};
-
-template <typename Context>
-std::unique_ptr<OutputFile<Context>>
-OutputFile<Context>::open(Context &ctx, std::string path, i64 filesize, i64 perm) {
-  Timer t(ctx, "open_file");
-
-  if (path.starts_with('/') && !ctx.arg.chroot.empty())
-    path = ctx.arg.chroot + "/" + path_clean(path);
-
-  bool is_special = false;
-  if (path == "-") {
-    is_special = true;
-  } else {
-    struct stat st;
-    if (stat(path.c_str(), &st) == 0 && (st.st_mode & S_IFMT) != S_IFREG)
-      is_special = true;
-  }
-
-  OutputFile<Context> *file;
-  if (is_special)
-    file = new MallocOutputFile(ctx, path, filesize, perm);
-  else
-    file = new MemoryMappedOutputFile(ctx, path, filesize, perm);
-
-#ifdef MADV_HUGEPAGE
-  // Enable transparent huge page for an output memory-mapped file.
-  // On Linux, it has an effect only on tmpfs mounted with `huge=advise`,
-  // but it can make the linker ~10% faster. You can try it by creating
-  // a tmpfs with the following commands
-  //
-  //  $ mkdir tmp
-  //  $ sudo mount -t tmpfs -o size=2G,huge=advise none tmp
-  //
-  // and then specifying a path under the directory as an output file.
-  madvise(file->buf, filesize, MADV_HUGEPAGE);
-#endif
-
-  if (ctx.arg.filler != -1)
-    memset(file->buf, ctx.arg.filler, filesize);
-  return std::unique_ptr<OutputFile>(file);
-}
-
-} // namespace mold

common/output-file-win32.h

@@ -1,57 +0,0 @@
-#include "mold.h"
-
-#include <fcntl.h>
-#include <filesystem>
-#include <windows.h>
-
-namespace mold {
-
-template <typename Context>
-class MallocOutputFile : public OutputFile<Context> {
-public:
-  MallocOutputFile(Context &ctx, std::string path, i64 filesize, i64 perm)
-    : OutputFile<Context>(path, filesize, false), perm(perm) {
-    this->buf = (u8 *)malloc(filesize);
-    if (!this->buf)
-      Fatal(ctx) << "malloc failed";
-  }
-
-  void close(Context &ctx) override {
-    Timer t(ctx, "close_file");
-
-    if (this->path == "-") {
-      fwrite(this->buf, this->filesize, 1, stdout);
-      fclose(stdout);
-      return;
-    }
-
-    i64 fd = ::open(this->path.c_str(), O_RDWR | O_CREAT, perm);
-    if (fd == -1)
-      Fatal(ctx) << "cannot open " << this->path << ": " << errno_string();
-
-    FILE *fp = fdopen(fd, "w");
-    fwrite(this->buf, this->filesize, 1, fp);
-    fclose(fp);
-    free(this->buf);
-  }
-
-private:
-  i64 perm;
-};
-
-template <typename Context>
-std::unique_ptr<OutputFile<Context>>
-OutputFile<Context>::open(Context &ctx, std::string path, i64 filesize, i64 perm) {
-  Timer t(ctx, "open_file");
-
-  if (path.starts_with('/') && !ctx.arg.chroot.empty())
-    path = ctx.arg.chroot + "/" + path_clean(path);
-
-  OutputFile<Context> *file = new MallocOutputFile(ctx, path, filesize, perm);
-
-  if (ctx.arg.filler != -1)
-    memset(file->buf, ctx.arg.filler, filesize);
-  return std::unique_ptr<OutputFile<Context>>(file);
-}
-
-} // namespace mold

common/output-file.h

@@ -1,5 +0,0 @@
-#if _WIN32
-# include "output-file-win32.h"
-#else
-# include "output-file-unix.h"
-#endif

common/sha.h

@@ -1,81 +0,0 @@
-#pragma once
-
-#include <cstdint>
-
-typedef uint8_t u8;
-static constexpr int64_t SHA256_SIZE = 32;
-
-#ifdef _WIN32
-// On Windows, we use Microsoft CNG.
-
-#include <Windows.h>
-#include <bcrypt.h>
-#include <ntstatus.h>
-
-inline static BCRYPT_ALG_HANDLE get_sha256_handle() {
-  static std::once_flag once;
-  static BCRYPT_ALG_HANDLE alg;
-
-  std::call_once(once, [&] {
-    BCryptOpenAlgorithmProvider(&alg, BCRYPT_SHA256_ALGORITHM, nullptr, 0);
-  });
-  return alg;
-}
-
-inline void sha256_hash(u8 *in, size_t len, u8 *out) {
-  BCryptHash(get_sha256_handle(), nullptr, 0, in, len, out, SHA256_SIZE);
-}
-
-class SHA256Hash {
-public:
-  SHA256Hash() {
-    BCryptCreateHash(get_sha256_handle(), &handle, nullptr, 0, nullptr, 0, 0);
-  }
-
-  void update(u8 *data, size_t len) {
-    BCryptHashData(handle, data, len, 0);
-  }
-
-  void finish(u8 *out) {
-    BCryptFinishHash(handle, out, SHA256_SIZE, 0);
-  }
-
-private:
-  BCRYPT_HASH_HANDLE handle;
-};
-
-#else
-// On Unix, we use OpenSSL or the Apple's OpenSSL-compatible API.
-
-#ifdef __APPLE__
-#  define COMMON_DIGEST_FOR_OPENSSL
-#  include <CommonCrypto/CommonDigest.h>
-#  define SHA256(data, len, md) CC_SHA256(data, len, md)
-#else
-#  define OPENSSL_SUPPRESS_DEPRECATED 1
-#  include <openssl/sha.h>
-#endif
-
-inline void sha256_hash(u8 *in, size_t len, u8 *out) {
-  SHA256(in, len, out);
-}
-
-class SHA256Hash {
-public:
-  SHA256Hash() {
-    SHA256_Init(&ctx);
-  }
-
-  void update(u8 *data, size_t len) {
-    SHA256_Update(&ctx, data, len);
-  }
-
-  void finish(u8 *out) {
-    SHA256_Final(out, &ctx);
-  }
-
-private:
-  SHA256_CTX ctx;
-};
-
-#endif

common/uuid.cc

@@ -1,20 +0,0 @@
-#include "common.h"
-
-#include <random>
-
-namespace mold {
-
-std::array<u8, 16> get_uuid_v4() {
-  std::array<u8, 16> bytes;
-
-  std::random_device rand;
-  u32 buf[4] = { rand(), rand(), rand(), rand() };
-  memcpy(bytes.data(), buf, 16);
-
-  // Indicate that this is UUIDv4 as defined by RFC4122.
-  bytes[6] = (bytes[6] & 0b00001111) | 0b01000000;
-  bytes[8] = (bytes[8] & 0b00111111) | 0b10000000;
-  return bytes;
-}
-
-} // namespace mold

dist.sh

@@ -1,40 +1,247 @@
 #!/bin/bash
-# This script creates a mold binary distribution. The output is
-# written in this directory as `mold-$version-$arch-linux.tar.gz`
-# (e.g. `mold-1.0.3-x86_64-linux.tar.gz`).
 #
-# The mold executable created by this script is statically-linked to
-# libstdc++ and libcrypto but dynamically-linked to libc, libm, libz
-# and librt, as they almost always exist on any Linux systems.
+# This script creates a mold binary distribution. The output is written to
+# the `dist` directory as `mold-$version-$arch-linux.tar.gz` (e.g.
+# `mold-2.40.0-x86_64-linux.tar.gz`).
+#
+# This script aims to produce reproducible outputs. That means each time
+# it's run on the same git commit, it generates a bit-for-bit identical
+# binary file regardless of when or where it's executed. This property
+# serves as a strong safeguard against supply chain attacks. With a
+# reproducible build, anyone can independently verify that the binary
+# files published on our GitHub release page were built from the git
+# commit tagged for release by rebuilding the binaries themselves.
+#
+# Debian provides snapshot.debian.org to host all historical binary
+# packages. We use it to construct a container image pinned to a
+# particular timestamp. snapshot.debian.org is known to be very slow,
+# but that shouldn't be a big problem for us because we only need that
+# site the first time.
+#
+# The mold executable created by this script is statically linked to
+# libstdc++, but dynamically linked to glibc, libm and a few other
+# libraries, as these libraries are almost always available on any Linux
+# system. We can't statically link glibc because doing so would disable
+# dlopen(), which is required to load the LTO linker plugin.
+#
+# We use a reasonably old Debian version for the build environment because
+# a binary dynamically linked against a newer version of glibc won't work
+# on a system with an older version of glibc.
+#
+# We prefer to build mold with Clang rather than GCC because mold's
+# Identical Code Folding works best with the LLVM address significance
+# table (.llvm_addrsig). Building a release binary with GCC produces a
+# slightly larger binary than with Clang.
+#
+# We need a recent version of Clang to build mold. If it's not available
+# via apt-get, we'll build it ourselves.
+#
+# This script can be used to create non-native binaries (e.g., building
+# aarch64 binary on x86-64) because Podman automatically runs everything
+# under QEMU if the container image is not native. To use this script for
+# non-native builds, you may need to install the qemu-user-static package.
+
+set -e -x
+cd "$(dirname $0)"
+
+usage() {
+  echo "Usage: $0 [ x86_64 | aarch64 | arm | riscv64 | ppc64le | s390x | loongarch64 ]"
+  exit 1
+}
 
 case $# in
 0)
   arch=$(uname -m)
-  [[ $arch = arm* ]] && arch=arm
+  if [ $arch = arm64 ]; then
+    arch=aarch64
+  elif [[ $arch = arm* ]]; then
+    arch=arm
+  fi
   ;;
 1)
   arch="$1"
   ;;
 *)
-  echo "Usage: $0 [ x86_64 | aarch64 | arm | ppc64le | s390x ]"
-  exit 1
+  usage
 esac
 
-echo "$arch" | grep -Eq '^(x86_64|aarch64|arm|ppc64le|s390x)$' || \
-  { echo "Error: no docker image for $arch"; exit 1; }
+# Create a Podman image.
+if [ "$GITHUB_REPOSITORY" = '' ]; then
+  image=mold-builder-$arch
+  image_build="podman build --arch $arch -t $image -"
+else
+  # If this script is running on GitHub Actions, we want to cache
+  # the created container image in GitHub's container repostiory.
+  image=ghcr.io/$GITHUB_REPOSITORY/mold-builder-$arch
+  image_build="podman build --arch $arch -t $image --output=type=registry --layers --cache-to $image --cache-from $image -"
+fi
 
-version=$(sed -n 's/^project(mold VERSION \(.*\))/\1/p' $(dirname $0)/CMakeLists.txt)
+case $arch in
+x86_64)
+  # Debian 9 (Stretch) released in June 2017.
+  #
+  # We use a Google-provided mirror (gcr.io) instead of the official Docker
+  # Hub (docker.io) because docker.io has a strict rate limit policy.
+  #
+  # The toolchain in Debian 9 is too old to build mold, so we rebuild it
+  # from source. We download source archives from official sites and build
+  # them locally, rather than downloading pre-built binaries from somewhere
+  # else, to avoid relying on unverifiable third-party binary blobs. Podman
+  # caches the result of each RUN command, so rebuilding is done only once
+  # per host.
+  cat <<EOF | $image_build
+FROM mirror.gcr.io/library/debian:stretch@sha256:c5c5200ff1e9c73ffbf188b4a67eb1c91531b644856b4aefe86a58d2f0cb05be
+ENV DEBIAN_FRONTEND=noninteractive TZ=UTC
+RUN sed -i -e '/^deb/d' -e 's/^# deb /deb /g' /etc/apt/sources.list && \
+  echo 'Acquire::Retries "10"; Acquire::http::timeout "10"; Acquire::Check-Valid-Until "false";' > /etc/apt/apt.conf.d/80-retries && \
+  apt-get update && \
+  apt-get install -y --no-install-recommends wget file make gcc g++ zlib1g-dev libssl-dev ca-certificates && \
+  rm -rf /var/lib/apt/lists
+
+# Build CMake 3.27
+RUN mkdir /build && \
+  cd /build && \
+  wget -O- --progress=dot:mega https://cmake.org/files/v3.27/cmake-3.27.7.tar.gz | tar xzf - --strip-components=1 && \
+  ./bootstrap --parallel=\$(nproc) && \
+  make -j\$(nproc) && \
+  make install && \
+  rm -rf /build
+
+# Build GCC 14
+RUN mkdir /build && \
+  cd /build && \
+  wget -O- --progress=dot:mega https://ftpmirror.gnu.org/gcc/gcc-14.2.0/gcc-14.2.0.tar.gz | tar xzf - --strip-components=1 && \
+  mkdir gmp mpc mpfr && \
+  wget -O- --progress=dot:mega https://ftpmirror.gnu.org/gmp/gmp-6.3.0.tar.gz | tar xzf - --strip-components=1 -C gmp && \
+  wget -O- --progress=dot:mega https://ftpmirror.gnu.org/mpc/mpc-1.3.1.tar.gz | tar xzf - --strip-components=1 -C mpc && \
+  wget -O- --progress=dot:mega https://ftpmirror.gnu.org/mpfr/mpfr-4.2.1.tar.gz | tar xzf - --strip-components=1 -C mpfr && \
+  ./configure --prefix=/usr --enable-languages=c,c++ --disable-bootstrap --disable-multilib && \
+  make -j\$(nproc) && \
+  make install && \
+  ln -sf /usr/lib64/libstdc++.so.6 /usr/lib/x86_64-linux-gnu/libstdc++.so.6 && \
+  rm -rf /build
+
+# Build GNU binutils 2.43
+RUN mkdir /build && \
+  cd /build && \
+  wget -O- --progress=dot:mega https://ftpmirror.gnu.org/binutils/binutils-2.43.tar.gz | tar xzf - --strip-components=1 && \
+  ./configure --prefix=/usr && \
+  make -j\$(nproc) && \
+  make install && \
+  rm -fr /build
+
+# Build Python 3.12.7
+RUN mkdir /build && \
+  cd /build && \
+  wget -O- --progress=dot:mega https://www.python.org/ftp/python/3.12.7/Python-3.12.7.tgz | tar xzf - --strip-components=1 && \
+  ./configure && \
+  make -j\$(nproc) && \
+  make install && \
+  rm -rf /build
+
+# Build LLVM 20
+RUN mkdir /build && \
+  cd /build && \
+  wget -O- --progress=dot:mega https://github.com/llvm/llvm-project/archive/refs/tags/llvmorg-20.1.3.tar.gz | tar xzf - --strip-components=1 && \
+  mkdir b && \
+  cd b && \
+  cmake -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_PROJECTS=clang ../llvm && \
+  cmake --build . -j\$(nproc) && \
+  cmake --install . --strip && \
+  rm -rf /build
+EOF
+  ;;
+aarch64 | arm | ppc64le | s390x)
+  # Debian 11 (Bullseye) released in August 2021
+  #
+  # We don't want to build Clang for these targets on QEMU becuase it
+  # would take an extremely long time. Also, I believe old Linux boxes
+  # are typically x86-64.
+  cat <<EOF | $image_build
+FROM mirror.gcr.io/library/debian:bullseye-20240904@sha256:8ccc486c29a3ad02ad5af7f1156e2152dff3ba5634eec9be375269ef123457d8
+ENV DEBIAN_FRONTEND=noninteractive TZ=UTC
+RUN sed -i -e '/^deb/d' -e 's/^# deb /deb /g' /etc/apt/sources.list && \
+  echo 'Acquire::Retries "10"; Acquire::http::timeout "10"; Acquire::Check-Valid-Until "false";' > /etc/apt/apt.conf.d/80-retries && \
+  apt-get update && \
+  apt-get install -y --no-install-recommends build-essential gcc-10 g++-10 clang-16 cmake && \
+  ln -sf /usr/bin/clang-16 /usr/bin/clang && \
+  ln -sf /usr/bin/clang++-16 /usr/bin/clang++ && \
+  rm -rf /var/lib/apt/lists
+EOF
+  ;;
+riscv64)
+  cat <<EOF | $image_build
+FROM mirror.gcr.io/riscv64/debian:unstable-20240926@sha256:25654919c2926f38952cdd14b3300d83d13f2d820715f78c9f4b7a1d9399bf48
+ENV DEBIAN_FRONTEND=noninteractive TZ=UTC
+RUN sed -i -e '/^URIs/d' -e 's/^# http/URIs: http/' /etc/apt/sources.list.d/debian.sources && \
+  echo 'Acquire::Retries "10"; Acquire::http::timeout "10"; Acquire::Check-Valid-Until "false";' > /etc/apt/apt.conf.d/80-retries && \
+  apt-get update && \
+  apt-get install -y --no-install-recommends build-essential gcc-14 g++-14 clang-18 cmake && \
+  ln -sf /usr/bin/clang-18 /usr/bin/clang && \
+  ln -sf /usr/bin/clang++-18 /usr/bin/clang++ && \
+  rm -rf /var/lib/apt/lists
+EOF
+  ;;
+loongarch64)
+  cat <<EOF | $image_build
+FROM mirror.gcr.io/loongarch64/debian:sid@sha256:0356df4e494bbb86bb469377a00789a5b42bbf67d5ff649a3f9721b745cbef77
+ENV DEBIAN_FRONTEND=noninteractive TZ=UTC
+RUN sed -i -e 's!http[^ ]*!http://snapshot.debian.org/archive/debian-ports/20250620T014755Z!g' /etc/apt/sources.list && \
+  echo 'Acquire::Retries "10"; Acquire::http::timeout "10"; Acquire::Check-Valid-Until "false";' > /etc/apt/apt.conf.d/80-retries && \
+  apt-get update && \
+  apt-get install -y --no-install-recommends build-essential gcc-14 g++-14 clang-19 cmake && \
+  ln -sf /usr/bin/clang-19 /usr/bin/clang && \
+  ln -sf /usr/bin/clang++-19 /usr/bin/clang++ && \
+  rm -rf /var/lib/apt/lists
+EOF
+  ;;
+*)
+  usage
+  ;;
+esac
+
+version=$(sed -n 's/^project(mold VERSION \(.*\))/\1/p' CMakeLists.txt)
 dest=mold-$version-$arch-linux
-set -e -x
 
-docker run --platform linux/$arch -it --rm -v "$(pwd):/mold" \
-  -e "OWNER=$(id -u):$(id -g)" rui314/mold-builder:latest \
-  bash -c "mkdir /tmp/build &&
-cd /tmp/build &&
-cmake -DCMAKE_C_COMPILER=gcc-10 -DCMAKE_CXX_COMPILER=g++-10 -DMOLD_MOSTLY_STATIC=On -DCMAKE_BUILD_TYPE=Release /mold &&
-cmake --build . -j\$(nproc) &&
-[ $arch = arm ] || ctest -j\$(nproc) &&
-cmake --install . --prefix $dest --strip &&
-tar czf /mold/$dest.tar.gz $dest &&
-cp mold mold-wrapper.so /mold &&
-chown \$OWNER /mold/mold /mold/mold-wrapper.so /mold/$dest.tar.gz"
+# Source tarballs available on GitHub don't contain .git directory.
+# Clone the repo if missing.
+[ -d .git ] || git clone --branch v$version --depth 1 --bare https://github.com/rui314/mold .git
+
+# We use the timestamp of the last Git commit as the file timestamp
+# for build artifacts.
+timestamp=$(git log -1 --format=%ct)
+
+# `uname -m` in an ARM32 container running on an ARM64 host reports it
+# not as ARM32 but as ARM64. That confuses BLAKE3's cmake script and
+# erroneously enables NEON SIMD instructions. `setarch` can be used to
+# change the output of `uname -m`.
+setarch=
+[ $arch = arm ] && setarch='setarch linux32'
+
+mkdir -p dist
+
+# Build mold in a container.
+#
+# SOURCE_DATE_EPOCH is a standardized environment variable that allows
+# build artifacts to appear as if they were built at a specific time.
+# We use it to control how the compiler expands the C/C++ __DATE__ and
+# __TIME__ macros.
+podman run --arch $arch -it --rm --userns=host --pids-limit=-1 --network=none \
+  --pull=never -v "$(pwd):/mold:ro" -v "$(pwd)/dist:/dist" $image \
+   $setarch bash -c "
+set -e
+export SOURCE_DATE_EPOCH=$timestamp
+mkdir /build
+cd /build
+cmake -DCMAKE_BUILD_TYPE=Release -DMOLD_MOSTLY_STATIC=1 -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ /mold
+cmake --build . -j\$(nproc)
+cmake --install .
+cmake -DMOLD_USE_MOLD=1 .
+cmake --build . -j\$(nproc)
+ctest --output-on-failure -j\$(nproc)
+cmake --install . --prefix $dest --strip
+find $dest -print | xargs touch --no-dereference --date=@$timestamp
+find $dest -print | sort | tar -cf - --no-recursion --files-from=- | gzip -9nc > /dist/$dest.tar.gz
+cp mold /dist
+sha256sum /dist/$dest.tar.gz
+"

docs/chart.svg

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docs/design.md

@@ -1,3 +1,8 @@
+[This document was written in 2020, and the contents are outdated.
+Specifically, we no longer believe that object preloading is a good
+idea. That being said, most of the points in this document still hold
+even today. Therefore, I'll keep this document as-is.]
+
 ## Design and implementation of mold
 
 For the rest of this documentation, I'll explain the design and the

docs/memory-sanitizer.md

@@ -0,0 +1,179 @@
+# Instrumenting mold with MemorySanitizer
+
+## Introduction
+
+Per <https://github.com/google/sanitizers/wiki/MemorySanitizerLibcxxHowTo>:
+
+> If you want MemorySanitizer to work properly and not produce any false
+> positives, you must ensure that all the code in your program and in
+> libraries it uses is instrumented (i.e. built with `-fsanitize=memory`).
+> In particular, you would need to link against an MSan-instrumented C++
+> standard library. We recommend to use [libc++](https://libcxx.llvm.org/)
+> for that purpose.
+
+## Building instrumented libc++
+
+Build an MSan-instrumented libc++ from source:
+
+```sh
+cd ~
+git clone https://github.com/llvm/llvm-project
+cd llvm-project
+cmake -S ./runtimes -B build-libcxx -G Ninja  \
+    -DCMAKE_BUILD_TYPE=Release                \
+    -DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi" \
+    -DCMAKE_C_COMPILER=clang                  \
+    -DCMAKE_CXX_COMPILER=clang++              \
+    -DLLVM_USE_SANITIZER=MemoryWithOrigins
+cmake --build build-libcxx -- cxx cxxabi
+export LIBCXX="$HOME/llvm-project/build-libcxx" # for subsequent build steps
+```
+
+Upon success, `./build-libcxx/{include,lib}` will contain the resulting
+headers and shared libraries.
+
+## Linking mold against instrumented libc++
+
+Use the `MOLD_USE_MSAN` and `MOLD_STDLIB_PREFIX` cmake variables to link
+mold against the instrumented build of libc++:
+
+```sh
+cd ~
+git clone https://github.com/rui314/mold.git
+cd mold
+cmake -B build -G Ninja            \
+    -DCMAKE_BUILD_TYPE=Debug       \
+    -DCMAKE_C_COMPILER=clang       \
+    -DCMAKE_CXX_COMPILER=clang++   \
+    -DMOLD_USE_MSAN=ON             \
+    -DMOLD_STDLIB_PREFIX="$LIBCXX" \
+    -DMOLD_USE_MIMALLOC=OFF        \
+    -DMOLD_USE_SYSTEM_TBB=ON
+cmake --build build
+```
+
+Most of mold's tests (except those for `-flto`) should work at this
+point. Run them like normal:
+
+```sh
+ctest --test-dir build
+```
+
+Any resulting MemorySanitizer errors should be visible in
+`./build/Temporary/Testing/LastTest.log`.
+
+## Building instrumented LTO plugin (experimental)
+
+Exercising `-flto` with MemorySanitizer (and without false positives)
+requires instrumenting the transitive dependencies of `lto-unix.cc`:
+
+- `libiberty.a`
+- `liblto_plugin.so`
+- `LLVMgold.so`
+
+> [!NOTE]
+> This is more involved and time-consuming than building only libc++ from
+> source. The cost-benefit ratio of this additional instrumentation and
+> test coverage may be unfavorable in many cases.
+
+> [!IMPORTANT]
+> The following steps are experimental and unlikely to work exactly as-is
+> under CI runners and individual developer environments. Consider the
+> following a starting point rather than a complete HOWTO.
+
+Build an MSan-instrumented GNU libiberty:
+
+```sh
+cd ~
+git clone [email protected]:gcc-mirror/gcc.git
+cd gcc/libiberty
+export CC=clang
+export CFLAGS="-g -Og -fsanitize=memory -fsanitize-memory-track-origins"
+export LDFLAGS="-fsanitize=memory"
+./configure
+make -j$(nproc)
+unset CC CFLAGS LDFLAGS
+```
+
+Install the resulting `./libiberty.a` into the build toolchain being
+tested with mold. If the system image is ephemeral or disposable (e.g. a
+short-lived VM or container), a quick-and-dirty install could look like:
+
+```sh
+sudo cp /usr/lib/libiberty.a{,.bak}
+sudo cp ./libiberty.a /usr/lib/
+```
+
+Build an MSan-instrumented GCC LTO plugin library:
+
+```sh
+cd ~/gcc/lto-plugin # use already-cloned repo from earlier step
+export CC=clang
+export CFLAGS="-g -Og -fsanitize=memory -fsanitize-memory-track-origins"
+export LDFLAGS="-fsanitize=memory"
+./configure --with-libiberty=/usr/lib
+make -j$(nproc)
+unset CC CFLAGS LDFLAGS
+```
+
+Install the resulting `liblto_plugin.so`. With the same caveats discussed
+above, a simple install into an ephemeral environment could look like:
+
+```sh
+export GCC_VERSION="$(gcc -dumpversion)"
+sudo cp /usr/lib/gcc/x86_64-pc-linux-gnu/$GCC_VERSION/liblto_plugin.so{,.bak}
+sudo cp .libs/liblto_plugin.so /usr/lib/gcc/x86_64-pc-linux-gnu/$GCC_VERSION/
+```
+
+Build an MSan-instrumented LLVM LTO plugin library:
+
+```sh
+cd ~/llvm-project # use already-cloned repo from earlier step
+
+CF="-nostdinc++ -isystem $LIBCXX/include/c++/v1"
+INCDIR="$(find /usr -name plugin-api.h -type f | head -1 | xargs dirname)"
+
+function configure
+{
+    cmake -S ./llvm -B build-plugin -G Ninja   \
+        -DLLVM_ENABLE_PROJECTS=clang           \
+        -DLLVM_TARGETS_TO_BUILD=X86            \
+        -DCMAKE_BUILD_TYPE=Release             \
+        -DCMAKE_C_COMPILER=clang               \
+        -DCMAKE_CXX_COMPILER=clang++           \
+        -DCMAKE_C_FLAGS="$CF"                  \
+        -DCMAKE_CXX_FLAGS="$CF"                \
+        -DCMAKE_EXE_LINKER_FLAGS="$1"          \
+        -DCMAKE_POSITION_INDEPENDENT_CODE=ON   \
+        -DLLVM_BINUTILS_INCDIR="$INCDIR"       \
+        -DLLVM_USE_SANITIZER=MemoryWithOrigins
+}
+
+# workaround for linker issues: configure twice with different LDFLAGS
+configure "-nostdlib++ -L $LIBCXX/lib -Wl,--rpath=$LIBCXX/lib"
+configure "-nostdlib++ -L $LIBCXX/lib -lc++ -Wl,--rpath=$LIBCXX/lib"
+
+cmake --build build-plugin -- LLVMgold.so
+```
+
+Install the resulting `LLVMgold.so`. With the same caveats discussed
+above, a simple install into an ephemeral environment could look like:
+
+```sh
+sudo cp /usr/lib/LLVMgold.so{,.bak}
+sudo cp ./build-plugin/lib/LLVMgold.so /usr/lib/
+```
+
+mold's tests for `-flto` should now (mostly) work, though there do seem
+to be issues around `gcc` inferring `-flto` when not explicitly specified.
+One workaround is to use `clang` as `TEST_CC`:
+
+```sh
+cd ~/mold # use already-cloned and built repo from earlier step
+TEST_CC=clang TEST_CXX=clang++ ctest --test-dir build
+```
+
+## References
+
+- <https://github.com/google/sanitizers/wiki/MemorySanitizerBootstrappingClang>
+- <https://llvm.org/docs/GoldPlugin.html#lto-how-to-build>

docs/mold.md

@@ -0,0 +1,985 @@
+mold(1) -- a modern linker
+==========================
+
+## SYNOPSIS
+
+`mold` [_option_...] _file_...
+
+## DESCRIPTION
+`mold` is a faster drop-in replacement for the default GNU ld(1).
+
+### How to use
+See <https://github.com/rui314/mold#how-to-use>.
+
+### Compatibility
+
+`mold` is designed to be a drop-in replacement for the GNU linkers for
+linking user-land programs. If your user-land program cannot be built due to
+missing command-line options, please file a bug at
+<https://github.com/rui314/mold/issues>.
+
+`mold` supports a very limited set of linker script features, which is just
+sufficient to read `/usr/lib/x86_64-linux-gnu/libc.so` on Linux systems (on
+Linux, that file is contrary to its name not a shared library but an ASCII
+linker script that loads a real `libc.so` file.)
+
+Beyond that, we have no plan to support any additional linker script features.
+The linker script is an ad-hoc, over-designed, complex language which we
+believe needs to be replaced by a simpler mechanism. We have a plan to add a
+replacement for the linker script to `mold` instead.
+
+### Archive symbol resolution
+
+Traditionally, Unix linkers are sensitive to the order in which input files
+appear on the command line. They process input files from the first (leftmost)
+file to the last (rightmost) file one-by-one. While reading input files, they
+maintain sets of defined and undefined symbols. When visiting an archive file
+(`.a` files), they pull out object files to resolve as many undefined symbols
+as possible and move on to the next input file. Object files that weren't
+pulled out will never have a chance for a second look.
+
+Due to this behavior, you usually have to add archive files at the end of a
+command line, so that when a linker reaches archive files, it knows what
+symbols remain as undefined.
+
+If you put archive files at the beginning of a command line, a linker doesn't
+have any undefined symbols, and thus no object files will be pulled out from
+archives. You can change the processing order by using the `--start-group` and
+`--end-group` options, though they make a linker slower.
+
+`mold`, as well as the LLVM lld(1) linker, takes a different approach. They
+remember which symbols can be resolved from archive files instead of
+forgetting them after processing each archive. Therefore, `mold` and lld(1)
+can "go back" in a command line to pull out object files from archives if they
+are needed to resolve remaining undefined symbols. They are not sensitive to
+the input file order.
+
+`--start-group` and `--end-group` are still accepted by `mold` and lld(1)
+for compatibility with traditional linkers, but they are silently ignored.
+
+### Dynamic symbol resolution
+
+Some Unix linker features are difficult to understand without comprehending
+the semantics of dynamic symbol resolution. Therefore, even though it's not
+specific to `mold`, we'll explain it here.
+
+We use "ELF module" or just "module" as a collective term to refer to an
+executable or a shared library file in the ELF format.
+
+An ELF module may have lists of imported symbols and exported symbols, as well
+as a list of shared library names from which imported symbols should be
+imported. The point is that imported symbols are not bound to any specific
+shared library until runtime.
+
+Here is how the Unix dynamic linker resolves dynamic symbols. Upon the start
+of an ELF program, the dynamic linker constructs a list of ELF modules which,
+as a whole, consist of a complete program. The executable file is always at
+the beginning of the list followed by its dependent shared libraries. An
+imported symbol is searched from the beginning of the list to the end. If two
+or more modules define the same symbol, the one that appears first in the list
+takes precedence over the others.
+
+This Unix semantics are contrary to systems such as Windows that have a
+two-level namespace for dynamic symbols. On Windows, for example, dynamic
+symbols are represented as a tuple of (`symbol-name`, `shared-library-name`),
+so that each dynamic symbol is guaranteed to be resolved from some specific
+library.
+
+Typically, an ELF module that exports a symbol also imports the same symbol.
+Such a symbol is usually resolved to itself, but that's not the case if a
+module that appears before it in the symbol search list provides another
+definition of the same symbol.
+
+Let's take `malloc` as an example. Assume that you define your version of
+`malloc` in your main executable file. Then, all `malloc` calls from any
+module are resolved to your function instead of the one in libc, because the
+executable is always at the beginning of the dynamic symbol search list. Note
+that even `malloc` calls within libc are resolved to your definition since
+libc exports and imports `malloc`. Therefore, by defining `malloc` yourself,
+you can overwrite a library function, and the `malloc` in libc becomes dead
+code.
+
+These Unix semantics are tricky and sometimes considered harmful. For example,
+assume that you accidentally define `atoi` as a global function in your
+executable that behaves completely differently from the one in the C standard.
+Then, all `atoi` function calls from any modules (even function calls within
+libc) are redirected to your function instead of the one in libc, which will
+very likely cause a problem. That is a somewhat surprising consequence for an
+accidental name conflict. On the other hand, this semantic is sometimes useful
+because it allows users to override library functions without rebuilding
+modules containing them.
+
+Whether good or bad, you should keep these semantics in mind to understand
+Unix linkers' behaviors.
+
+### Build reproducibility
+
+`mold`'s output is deterministic. That is, if you pass the same object files
+and the same command-line options to the same version of `mold`, it is
+guaranteed that `mold` produces the bit-for-bit identical output. The linker's
+internal randomness, such as the timing of thread scheduling or iteration
+orders of hash tables, doesn't affect the output.
+
+`mold` does not have any host-specific default settings. This is contrary to the
+GNU linkers, for which some configurable values, such as system-dependent
+library search paths, are hard-coded. `mold` depends only on its command-line
+arguments.
+
+## OPTION NOTATIONS
+
+Multi-letter long options may precede either a single dash or double dashes,
+except for those starting with the letter "o". For historical reasons, long
+options beginning with "o" must precede double dashes.
+
+For example, you can spell `--as-needed` as `-as-needed`, but `--omagic` must
+not be spelled as `-omagic`. `-omagic` will be interpreted not as `--omagic`
+but as `-o magic`.
+
+## MOLD-SPECIFIC OPTIONS
+
+* `--chroot`=_dir_:
+  Set _dir_ as the root directory.
+
+* `--color-diagnostics`=[ _auto_ | _always_ | _never_ ]:
+  Show diagnostic messages in color using ANSI escape sequences. `auto` means
+  that `mold` prints out messages in color only if the standard output is
+  connected to a TTY. Default is `auto`.
+
+* `--color-diagnostics`:
+  Synonym for `--color-diagnostics=auto`.
+
+* `--no-color-diagnostics`:
+  Synonym for `--color-diagnostics=never`.
+
+* `--detach`, `--no-detach`:
+  Permit or do not permit mold to create a debug info file in the background.
+
+* `--fork`, `--no-fork`:
+  Spawn a child process and let it do the actual linking. When linking a large
+  program, the OS kernel can take a few hundred milliseconds to terminate a
+  `mold` process. `--fork` hides that latency. By default, it does fork.
+
+  Note that `--fork` also hides the resource usage statistics reported by
+  time(2), since it doesn't call waitpid(2) on the child process. If you
+  need those statistics, pass `--no-fork`.
+
+* `--perf`:
+  Print performance statistics.
+
+* `--print-dependencies`:
+  Print out dependency information for input files.
+
+  Each line of the output for this option shows which file depends on which
+  file to use a specific symbol. This option is useful for debugging why some
+  object file in a static archive got linked or why some shared library is
+  kept in an output file's dependency list even with `--as-needed`.
+
+* `--relocatable-merge-sections`:
+  By default, `mold` doesn't merge input sections by name when merging input
+  object files into a single output object file for `-r`. For example,
+  `.text.foo` and `.text.bar` aren't merged for `-r` even though they are
+  merged into `.text` based on the default section merging rules.
+
+  This option changes the behavior so that `mold` merges input sections by
+  name by the default section merging rules.
+
+* `--repro`:
+  Archive input files, as well as a text file containing command line options,
+  in a tar file so that you can run `mold` with the exact same inputs again.
+  This is useful for reporting a bug with a reproducer. The output filename is
+  `path/to/output.tar`, where `path/to/output` is an output filename specified
+  by `-o`.
+
+* `--reverse-sections`:
+  Reverse the order of input sections before assigning them the offsets in the
+  output file.
+
+  This option is useful for finding bugs that depend on the initialization
+  order of global objects. In C++, constructors of global objects in a single
+  source file are guaranteed to be executed in the source order, but there's
+  no such guarantee across compilation units. Usually, constructors are
+  executed in the order given to the linker, but depending on it is a mistake.
+
+  By reversing the order of input sections using `--reverse-sections`, you can
+  easily test that your program works in the reversed initialization order.
+
+* `--run` _command_ _arg_...:
+  Run _command_ with `mold` as `/usr/bin/ld`. Specifically, `mold` runs a
+  given command with the `LD_PRELOAD` environment set to intercept exec(3)
+  family functions and replaces `argv[0]` with itself if it is `ld`,
+  `ld.gold`, or `ld.lld`.
+
+* `--separate-debug-file`, `--separate-debug-file`=_file_:
+  Bundle debug info sections into a separate file instead of embedding them in
+  an output executable or a shared library. mold creates a debug info file in
+  the background by default, so that you can start running your executable as
+  soon as possible.
+
+  By default, the debug info file is created in the same directory as is the
+  output file, with the `.dbg` file extension. That filename is embedded into
+  the output file so that `gdb` can automatically find the debug info file for
+  the output file. For more info about gdb features related to separate debug
+  files, see
+  <https://sourceware.org/gdb/current/onlinedocs/gdb.html/Separate-Debug-Files.html>.
+
+  mold holds a file lock with flock(2) while creating a debug info file in the
+  background.
+
+  If you don't want to create a debug info file in the background, pass the
+  `--no-detach` option.
+
+* `--shuffle-sections`, `--shuffle-sections`=_number_:
+  Randomize the output by shuffling the order of input sections before
+  assigning them the offsets in the output file. If a _number_ is given, it's
+  used as a seed for the random number generator, so that the linker produces
+  the same output for the same seed. If no seed is given, a random number is
+  used as a seed.
+
+  This option is useful for benchmarking. Modern CPUs are sensitive to a
+  program's memory layout. A seemingly benign change in program layout, such
+  as a small size increase of a function in the middle of a program, can
+  affect the program's performance. Therefore, even if you write new code and
+  get a good benchmark result, it is hard to say whether the new code improves
+  the program's performance; it is possible that the new memory layout happens
+  to perform better.
+
+  By running a benchmark multiple times with randomized memory layouts using
+  `--shuffle-sections`, you can isolate your program's real performance number
+  from the randomness caused by memory layout changes.
+
+* `--spare-program-headers`=_number_:
+  Append the given number of `PT_NULL` entries to the end of the program
+  header, so that post-link processing tools can easily add new segments by
+  overwriting the null entries.
+
+  Note that ELF requires all `PT_LOAD` segments to be sorted by `p_vaddr`.
+  Therefore, if you add a new LOAD segment, you may need to sort the entire
+  program header.
+
+* `--stats`:
+  Print input statistics.
+
+* `--thread-count`=_count_:
+  Use _count_ number of threads.
+
+* `--threads`, `--no-threads`:
+  Use multiple threads. By default, `mold` uses as many threads as the number of
+  cores or 32, whichever is smaller. The reason it is capped at 32 is because
+  `mold` doesn't scale well beyond that point. To use only one thread, pass
+  `--no-threads` or `--thread-count=1`.
+
+* `--quick-exit`, `--no-quick-exit`:
+  Use or do not use `quick_exit` to exit.
+
+* `--zero-to-bss`:
+  Convert all-zero data sections into BSS.
+
+  When this option is enabled, `mold` scans input data sections that are not
+  of type `SHT_NOBITS` and checks whether their contents consist solely of
+  zero bytes. Such sections are then converted into BSS (`SHT_NOBITS`)
+  sections. This reduces the size of the output file, since BSS sections
+  occupy no space in the file image.
+
+  This behavior is especially useful for user-defined sections created with
+  `__attribute__((section(".sectname")))` that contain uninitialized global
+  variables. GCC and Clang do not automatically mark such sections as BSS
+  even if their contents are entirely zero, and instead emit them as regular
+  data sections.
+
+  For example, consider `__attribute__((section(".sectname"))) int vec[256];`.
+
+  By default, this results in a `.sectname` section of type `SHT_PROGBITS`
+  filled with zeros. With `--zero-to-bss`, the linker will recognize it as
+  empty data and convert it to a `SHT_NOBITS` section, reducing the output
+  file size without changing runtime semantics.
+
+* `-z rewrite-endbr`, `-z norewrite-endbr`:
+  As a security measure, some CPU instruction sets have recently gained a
+  feature to protect control flow integrity by disallowing indirect branches
+  by default. If the feature is enabled, the instruction that is executed
+  immediately after an indirect branch must be an branch target marker
+  instruction, or a CPU-level fault will raise. The marker instruction is also
+  known as "landing pad" instruction, to which indirect branches can land.
+  This feature makes ROP attacks harder to conduct.
+
+  To use the feature, a function whose pointer is taken needs to begin with a
+  landing pad because a function call via a function pointer is compiled to an
+  indirect branch. On the other hand, if a function is called only directly
+  (i.e. referred to only by _direct_ branch instructions), it doesn't have to
+  begin with it.
+
+  By default, the compiler always emits a landing pad at the beginning of each
+  global function because it doesn't know whether or not the function's
+  pointer is taken in another translation unit. As a result, the resulting
+  binary has more attack surface than necessary.
+
+  If `--rewrite-endbr` is given, mold conducts a whole program analysis
+  to identify functions whose addresses are actually taken and rewrites
+  landing pads with no-ops for non-address-taken functions, reducing the
+  attack surface.
+
+  This feature is currently available only on x86-64.
+
+## GNU-COMPATIBLE OPTIONS
+
+* `--help`:
+  Report usage information to stdout and exit.
+
+* `-v`, `--version`:
+  Report version information to stdout.
+
+* `-V`:
+  Report version and target information to stdout.
+
+* `-E`, `--export-dynamic`, `--no-export-dynamic`:
+  When creating an executable, using the `-E` option causes all global symbols
+  to be put into the dynamic symbol table, so that the symbols are visible
+  from other ELF modules at runtime.
+
+  By default, or if `--no-export-dynamic` is given, only symbols that are
+  referenced by DSOs at link-time are exported from an executable.
+
+* `-F` _libname_, `--filter`=_libname_:
+  Set the `DT_FILTER` dynamic section field to _libname_.
+
+* `-I` _file_, `--dynamic-linker`=_file_, `--no-dynamic-linker`:
+  Set the dynamic linker path to _file_. If no `-I` option is given, or if
+  `--no-dynamic-linker` is given, no dynamic linker path is set to an output
+  file. This is contrary to the GNU linkers which set a default dynamic linker
+  path in that case. This difference doesn't usually make any difference
+  because the compiler driver always passes `-I` to the linker.
+
+* `-L` _dir_, `--library-path`=_dir_:
+  Add _dir_ to the list of library search paths from which `mold` searches
+  libraries for the `-l` option.
+
+  Unlike the GNU linkers, `mold` does not have default search paths. This
+  difference doesn't usually make any difference because the compiler driver
+  always passes all necessary search paths to the linker.
+
+* `-M`, `--print-map`:
+  Write a map file to stdout.
+
+* `-N`, `--omagic`, `--no-omagic`:
+  Force `mold` to emit an output file with an old-fashioned memory layout.
+  First, it makes the first data segment not aligned to a page boundary.
+  Second, text segments are marked as writable if the option is given.
+
+* `-S`, `--strip-debug`:
+  Omit `.debug_*` sections from the output file.
+
+* `-T` _file_, `--script`=_file_:
+  Read linker script from _file_.
+
+* `-X`, `--discard-locals`:
+  Discard temporary local symbols to reduce the sizes of the symbol table and
+  the string table. Temporary local symbols are local symbols starting with
+  `.L`. Compilers usually generate such symbols for unnamed program elements
+  such as string literals or floating-point literals.
+
+* `-e` _symbol_, `--entry`=_symbol_:
+
+  Use _symbol_ as the entry point symbol instead of the default entry
+  point symbol _start.
+
+* `-f` _shlib_, `--auxiliary`=_shlib_:
+  Set the `DT_AUXILIARY` dynamic section field to _shlib_.
+
+* `-h` _libname_, `--soname`=_libname_:
+  Set the `DT_SONAME` dynamic section field to _libname_. This option is used
+  when creating a shared object file. Typically, when you create `libfoo.so`,
+  you want to pass `--soname=foo` to a linker.
+
+* `-l` _libname_:
+  Search for `lib`_libname_`.so` or `lib`_libname_`.a` from library search
+  paths.
+
+* `-m` _target_:
+  Choose a _target_.
+
+* `-o` _file_, `--output`=_file_:
+  Use _file_ as the output file name instead of the default name `a.out`.
+
+* `-r`, `--relocatable`:
+  Instead of generating an executable or a shared object file, combine input
+  object files to generate another object file that can be used as an input to
+  a linker.
+
+* `-s`, `--strip-all`:
+  Omit `.symtab` section from the output file.
+
+* `-u` _symbol_, `--undefined`=_symbol_:
+  If _symbol_ remains as an undefined symbol after reading all object files,
+  and if there is a static archive that contains an object file defining
+  _symbol_, pull out the object file and link it so that the output file
+  contains a definition of _symbol_.
+
+* `-y` _symbol_, `--trace-symbol`=_symbol_:
+  Trace references to _symbol_.
+
+* `--Bdynamic`:
+  Link against shared libraries.
+
+* `--Bstatic`:
+  Do not link against shared libraries.
+
+* `--Bsymbolic`:
+  When creating a shared library, make global symbols export-only (i.e. do not
+  import the same symbol). As a result, references within a shared library are
+  always resolved locally, negating symbol override at runtime. See "Dynamic
+  symbol resolution" for more information about symbol imports and exports.
+
+* `--Bsymbolic-functions`:
+  This option has the same effect as `--Bsymbolic` but works only for function
+  symbols. Data symbols remain being both imported and exported.
+
+* `--Bsymbolic-non-weak`:
+  This option has the same effect as `--Bsymbolic` but works only for non-weak
+  symbols. Weak symbols remain being both imported and exported.
+
+* `--Bsymbolic-non-weak-functions`:
+  This option has the same effect as `--Bsymbolic` but works only for non-weak
+  function symbols. Data symbols and weak function symbols remain being both
+  imported and exported.
+
+* `--Bno-symbolic`:
+  Cancel `--Bsymbolic`, `--Bsymbolic-functions`, `--Bsymbolic-non-weak` and
+  `--Bsymbolic-non-weak-functions`.
+
+* `--Map`=_file_:
+  Write map file to _file_.
+
+* `--Tbss`=_address_:
+  Alias for `--section-start=.bss=`_address_.
+
+* `--Tdata`=_address_:
+  Alias for `--section-start=.data=`_address_.
+
+* `--Ttext`=_address_:
+  Alias for `--section-start=.text=`_address_.
+
+* `--allow-multiple-definition`:
+  Normally, the linker reports an error if there are more than one definition
+  of a symbol. This option changes the default behavior so that it doesn't
+  report an error for duplicate definitions and instead use the first
+  definition.
+
+* `--allow-shlib-undefined`, `--no-allow-shlib-undefined`:
+  Even if mold succeeds in linking a main executable without undefined symbol
+  errors, you may still encounter symbol lookup errors at runtime because the
+  dynamic linker cannot find some symbols in shared libraries in any ELF
+  module. This occurs because mold ignores undefined symbols in shared
+  libraries by default.
+
+  If you pass `--no-allow-shlib-undefined`, mold verifies that undefined
+  symbols in shared libraries given to the linker can be resolved at
+  link-time. In other words, this converts the runtime error to a link-time
+  error.
+
+  Note that you need to pass all shared libraries, including indirectly
+  dependent ones, to the linker as arguments for `-l`. If a shared library
+  depends on a library that's not passed to the linker, the verification will
+  be skipped for that file.
+
+* `--as-needed`, `--no-as-needed`:
+  By default, shared libraries given to the linker are unconditionally added
+  to the list of required libraries in an output file. However, shared
+  libraries after `--as-needed` are added to the list only when at least one
+  symbol is actually used by the output file. In other words, shared libraries
+  after `--as-needed` are not added to the list of needed libraries if they
+  are not needed by a program.
+
+  The `--no-as-needed` option restores the default behavior for subsequent
+  files.
+
+* `--build-id`=[ `md5` | `sha1` | `sha256` | `fast` | `uuid` | `0x`_hexstring_ | `none` ]:
+  Create a `.note.gnu.build-id` section containing a byte string to uniquely
+  identify an output file. `sha256` compute a 256-bit cryptographic hash of an
+  output file and set it to build-id. `md5` and `sha1` compute the same hash
+  but truncate it to 128 and 160 bits, respectively, before setting it to
+  build-id. `uuid` sets a random 128-bit UUID. `0x`_hexstring_ sets
+  _hexstring_. `fast` is a synonym for `sha256`.
+
+* `--build-id`:
+  Synonym for `--build-id=sha256`.
+
+* `--no-build-id`:
+  Synonym for `--build-id=none`.
+
+* `--compress-debug-sections`=[ `zlib` | `zlib-gabi` | `zlib:`_N_ | `zstd` | `zstd:`_N_ | `none` ]:
+  Compress DWARF debug info (`.debug_*` sections) using the zlib or zstd
+  compression algorithm. `zlib-gabi` is an alias for `zlib`. `zlib:`_N_
+  selects the zlib compression level, where _N_ is between 0 and 9 (0
+  means no compression), and `zstd:`_N_ selects the zstd compression
+  level, where _N_ is between 1 and 22. Higher levels achieve better
+  compression ratios but are slower. `zlib` is equivalent to `zlib:1`
+  and `zstd` is equivalent to `zstd:3`.
+
+* `--defsym`=_symbol_=_value_:
+  Define _symbol_ as an alias for _value_.
+
+  _value_ is either an integer (in decimal or hexadecimal with `0x` prefix) or
+  a symbol name. If an integer is given as a value, _symbol_ is defined as an
+  absolute symbol with the given value.
+
+* `--default-symver`:
+  Use soname as a symbol version and append that version to all symbols.
+
+* `--demangle`, `--no-demangle`:
+  Demangle C++ and Rust symbols in log messages.
+
+* `--dependency-file`=_file_:
+  Write a dependency file to _file_. The contents of the written file is
+  readable by make(1), which defines only one rule with the linker's output
+  file as a target and all input files as its prerequisites. Users are
+  expected to include the generated dependency file into a Makefile to
+  automate the dependency management. This option is analogous to the
+  compiler's `-MM -MF` options.
+
+* `--dynamic-list`=_file_:
+  Read a list of dynamic symbols from _file_. Same as
+  `--export-dynamic-symbol-list`, except that it implies `--Bsymbolic`. If
+  _file_ does not exist in the current directory, it is searched from library
+  search paths for the sake of compatibility with GNU ld.
+
+* `--eh-frame-hdr`, `--no-eh-frame-hdr`:
+  Create `.eh_frame_hdr` section.
+
+* `--emit-relocs`:
+  The linker usually "consumes" relocation sections. That is, the linker
+  applies relocations to other sections, and relocation sections themselves
+  are discarded.
+
+  The `--emit-relocs` instructs the linker to leave relocation sections in the
+  output file. Some post-link binary analysis or optimization tools such as
+  LLVM Bolt need them.
+
+* `--enable-new-dtags`, `--disable-new-dtags`:
+  By default, `mold` emits `DT_RUNPATH` for `--rpath`. If you pass
+  `--disable-new-dtags`, `mold` emits `DT_RPATH` for `--rpath` instead.
+
+* `--execute-only`:
+
+  Traditionally, setting the executable bit to 1 for a memory page implies
+  that the page also become readable, which allows machine code to be read
+  as data at runtime. That is actually what an attacker often does after
+  gaining a limited control of a process to find pieces of machine code
+  they can use to gain the full control of the process. As a mitigation,
+  recent processors including some ARM64 ones allows "execute-only" pages.
+  If a page is execute-only, you can call a function there as long as you
+  know its address but can't read it as data.
+
+  This option marks text segments as execute-only by setting just the "X"
+  bit instead of "RX". Note that on most systems, the absence of the "R"
+  bit in the text segment serves just as a hint. If you run a program
+  linked with `--execute-only` on a processor that doesn't support
+  execute-only pages, your executable will likely still function normally,
+  but the text segment will remain readable.
+
+* `--exclude-libs`=_libraries_ ...:
+  Mark all symbols in the given _libraries_ hidden.
+
+* `--export-dynamic-symbol`=_symbol_:
+  Put symbols matching _symbol_ in the dynamic symbol table. _symbol_ may be a
+  glob pattern in the same syntax as for the `--export-dynamic-symbol-list` or
+  `--version-script` options.
+
+* `--export-dynamic-symbol-list`=_file_:
+  Read a list of dynamic symbols from _file_.
+
+* `--fatal-warnings`, `--no-fatal-warnings`:
+  Treat warnings as errors.
+
+* `--fini`=_symbol_:
+  Call _symbol_ at unload-time.
+
+* `--gc-sections`, `--no-gc-sections`:
+  Remove unreferenced sections.
+
+* `--gdb-index`:
+  Create a `.gdb_index` section to speed up GNU debugger. To use this, you
+  need to compile source files with the `-ggnu-pubnames` compiler flag.
+
+* `--hash-style`=[ `sysv` | `gnu` | `both` | `none` ]:
+  Set hash style.
+
+* `--icf`=[ `safe` | `all` | `none` ], `--no-icf`:
+  It is not uncommon for a program to contain many identical functions that
+  differ only in name. For example, a C++ template `std::vector` is very
+  likely to be instantiated to the identical code for `std::vector<int>` and
+  `std::vector<unsigned>` because the container cares only about the size of
+  the parameter type. Identical Code Folding (ICF) is a size optimization to
+  identify and merge such identical functions.
+
+  If `--icf=all` is given, `mold` tries to merge all identical functions. This
+  reduces the size of the output most, but it is not a "safe" optimization. It
+  is guaranteed in C and C++ that two pointers pointing two different
+  functions will never be equal, but `--icf=all` breaks that assumption as two
+  identical functions have the same address after merging. So a care must be
+  taken when you use this flag that your program does not depend on the
+  function pointer uniqueness.
+
+  `--icf=safe` is a flag to merge functions only when it is safe to do so.
+  That is, if a program does not take an address of a function, it is safe to
+  merge that function with other function, as you cannot compare a function
+  pointer with something else without taking an address of a function.
+
+  `--icf=safe` needs to be used with a compiler that supports `.llvm_addrsig`
+  section which contains the information as to what symbols are address-taken.
+  LLVM/Clang supports that section by default. Since GCC does not support it
+  yet, you cannot use `--icf=safe` with GCC (it doesn't do any harm but can't
+  optimize at all.)
+
+  `--icf=none` and `--no-icf` disables ICF.
+
+* `--ignore-data-address-equality`:
+  Make ICF to merge not only functions but also data. This option should be
+  used in combination with `--icf=all`.
+
+* `--image-base`=_addr_:
+  Set the base address to _addr_.
+
+* `--init`=_symbol_:
+  Call _symbol_ at load-time.
+
+* `--no-undefined`:
+  Report undefined symbols (even with `--shared`).
+
+* `--noinhibit-exec`:
+  Create an output file even if errors occur.
+
+* `--package-metadata`=_percent-encoded-string_:
+  Embed a specified string into the `.note.package` section. This option
+  is designed for build scripts that generate binary packages, such as
+  `.rpm` or `.deb`, to include package metadata in each executable. It
+  simplifies the process of identifying the corresponding package for a
+  given executable or core file.
+
+  An argument to this option is treated as percent-encoded and decoded
+  before being inserted into the section, allowing you to avoid the use of
+  the comma (`,`) character in the argument. This is useful because the
+  compiler replaces all occurrences of commas in `-Wl,` with spaces before
+  forwarding them to the linker. Note that `mold` always interprets the
+  argument as percent-encoded, so you also need to escape all occurrences
+  of `%` as `%25`.
+
+* `--pack-dyn-relocs`=[ `relr` | `android` | `android+relr` | `none` ]:
+  Compress dynamic relocations in the output file.
+
+  If `relr` is specified, all `R_*_RELATIVE` relocations are put into
+  `.relr.dyn` section instead of `.rel.dyn` or `.rela.dyn` section. Since
+  `.relr.dyn` section uses a space-efficient encoding scheme, specifying this
+  flag can reduce the size of the output. This is typically most effective for
+  position-independent executable.
+
+  If `android` is specified, all dynamic relocations are encoded in Android's
+  packed relocation format (APS2) and stored in the `.rel.dyn` or `.rela.dyn`
+  section, whose section type is changed to `SHT_ANDROID_REL` or
+  `SHT_ANDROID_RELA`. The dynamic table is updated to use `DT_ANDROID_REL`
+  / `DT_ANDROID_RELA` and their `SZ` variants in place of the standard tags.
+
+  `android+relr` combines both: `R_*_RELATIVE` relocations go to `.relr.dyn`
+  and the rest are APS2-encoded. This is the configuration used by most
+  Android system binaries.
+
+  Note that a runtime loader has to support `.relr.dyn` to run executables or
+  shared libraries linked with `--pack-dyn-relocs=relr`. As of 2026, glibc
+  (since 2.36), musl (since 1.2.4), Android, ChromeOS, and Fuchsia all
+  support it. The APS2 format, on the other hand, is only handled by
+  Android's bionic loader; the encoder itself is target-agnostic, but the
+  produced binary can only be loaded on platforms where bionic (or a
+  compatible loader) handles `DT_ANDROID_REL(A)`.
+
+* `--pie`, `--pic-executable`, `--no-pie`, `--no-pic-executable`:
+  Create a position-independent executable.
+
+* `--print-gc-sections`, `--no-print-gc-sections`:
+  Print removed unreferenced sections.
+
+* `--print-icf-sections`, `--no-print-icf-sections`:
+  Print folded identical sections.
+
+* `--push-state`, `--pop-state`:
+  `--push-state` saves the current values of `--as-needed`, `--whole-archive`,
+  `--static`, and `--start-lib`. The saved values can be restored by
+  pop-state.
+
+  `--push-state` and `--pop-state` pairs can nest.
+
+  These options are useful when you want to construct linker command line
+  options programmatically. For example, if you want to link `libfoo.so` by
+  as-needed basis but don't want to change the global state of `--as-needed`,
+  you can append `--push-state --as-needed -lfoo --pop-state` to the linker
+  command line options.
+
+* `--relax, --no-relax`:
+  Rewrite machine instructions with more efficient ones for some relocations.
+  The feature is enabled by default.
+
+* `--require-defined`=_symbol_:
+  Like `--undefined`, except the new symbol must be defined by the end of the
+  link.
+
+* `--retain-symbols-file`=_file_:
+  Keep only symbols listed in _file_. _file_ is a text file containing a
+  symbol name on each line. `mold` discards all local symbols as well as
+  global symbol that are not in _file_. Note that this option removes symbols
+  only from `.symtab` section and does not affect `.dynsym` section, which is
+  used for dynamic linking.
+
+* `--rpath`=_dir_:
+  Add _dir_ to runtime search paths.
+
+* `--section-start`=_section_=_address_:
+  Set _address_ to section. _address_ is a hexadecimal number that may start
+  with an optional `0x`.
+
+* `--shared`, `--Bshareable`:
+  Create a share library.
+
+* `--spare-dynamic-tags`=_number_:
+  Append the given number of `DT_NULL` entries to the end of the `.dynamic`
+  section, so that post-link processing tools can easily add new dynamic tags
+  by overwriting the null entries.
+
+* `--start-lib`, `--end-lib`:
+  Handle object files between `--start-lib` and `--end-lib` as if they were in
+  an archive file. That means object files between them are linked only when
+  they are needed to resolve undefined symbols. The options are useful if you
+  want to link object files only when they are needed but want to avoid the
+  overhead of running ar(3).
+
+* `--static`:
+  Do not link against shared libraries.
+
+* `--sysroot`=_dir_:
+  Set target system root directory to _dir_.
+
+* `--trace`:
+  Print name of each input file.
+
+* `--undefined-glob`=_pattern_:
+  Synonym for `--undefined`, except that `--undefined-glob` takes a glob
+  pattern instead of just a single symbol name.
+
+* `--undefined-version`, `--no-undefined-version`:
+  By default, `mold` warns on a symbol specified by a version script or by
+  `--export-dynamic-symbol` if it is not defined. You can silence the warning
+  by `--undefined-version`.
+
+* `--unique`=_pattern_:
+  Don't merge input sections that match the given glob pattern _pattern_.
+
+* `--unresolved-symbols`=[ `report-all` | `ignore-all` | `ignore-in-object-files` | `ignore-in-shared-libs` ]:
+  How to handle undefined symbols.
+
+* `--version-script`=_file_:
+  Read version script from _file_. If _file_ does not exist in the current
+  directory, it is searched from library search paths for the sake of
+  compatibility with GNU ld.
+
+* `-w`, `--no-warnings`:
+  Suppress warnings and cancel `--fatal-warnings`.
+
+* `--warn-common`, `--no-warn-common`:
+  Warn about common symbols.
+
+* `--warn-once`:
+  Only warn once for each undefined symbol instead of warn for each relocation
+  referring an undefined symbol.
+
+* `--warn-unresolved-symbols`, `--error-unresolved-symbols`:
+  Normally, the linker reports an error for unresolved symbols.
+  `--warn-unresolved-symbols` option turns it into a warning.
+  `--error-unresolved-symbols` option restores the default behavior.
+
+* `--whole-archive`, `--no-whole-archive`:
+  When archive files (`.a` files) are given to the linker, only object files
+  that are needed to resolve undefined symbols are extracted from them and
+  linked to an output file. `--whole-archive` changes that behavior for
+  subsequent archives so that the linker extracts all object files and links
+  them to an output. For example, if you are creating a shared object file and
+  you want to include all archive members to the output, you should pass
+  `--whole-archive`. `--no-whole-archive` restores the default behavior for
+  subsequent archives.
+
+* `--wrap`=_symbol_:
+  Make _symbol_ be resolved to `__wrap_`_symbol_. The original symbol can be
+  resolved as `__real_`_symbol_. This option is typically used for wrapping an
+  existing function.
+
+* `-z cet-report`=[ `warning` | `error` | `none` ]:
+  Intel Control-flow Enforcement Technology (CET) is a new x86 feature
+  available since Tiger Lake which is released in 2020. It defines new
+  instructions to harden security to protect programs from control hijacking
+  attacks. You can tell the compiler to use the feature by specifying the
+  `-fcf-protection` flag.
+
+  `-z cet-report` flag is used to make sure that all object files were
+  compiled with a correct `-fcf-protection` flag. If `warning` or `error` are
+  given, `mold` prints out a warning or an error message if an object file was
+  not compiled with the compiler flag.
+
+  `mold` looks for `GNU_PROPERTY_X86_FEATURE_1_IBT` bit and
+  `GNU_PROPERTY_X86_FEATURE_1_SHSTK` bit in `.note.gnu.property` section to
+  determine whether or not an object file was compiled with `-fcf-protection`.
+
+* `-z now`, `-z lazy`:
+  By default, functions referring to other ELF modules are resolved by the
+  dynamic linker when they are called for the first time. `-z now` marks an
+  executable or a shared library file so that all dynamic symbols are resolved
+  when a file is loaded to memory. `-z lazy` restores the default behavior.
+
+* `-z origin`:
+  Mark object requiring immediate `$ORIGIN` processing at runtime.
+
+* `-z ibt`:
+  Turn on `GNU_PROPERTY_X86_FEATURE_1_IBT` bit in `.note.gnu.property` section
+  to indicate that the output uses IBT-enabled PLT. This option implies `-z
+  ibtplt`.
+
+* `-z ibtplt`:
+  Generate Intel Branch Tracking (IBT)-enabled PLT which is the default on
+  x86-64. This is the default.
+
+* `-z execstack`, `-z noexecstack`:
+  By default, the pages for the stack area (i.e. the pages where local
+  variables reside) are not executable for security reasons. `-z execstack`
+  makes it executable. `-z noexecstack` restores the default behavior.
+
+* `-z keep-text-section-prefix`, `-z nokeep-text-section-prefix`:
+  Keep `.text.hot`, `.text.unknown`, `.text.unlikely`, `.text.startup`, and
+  `.text.exit` as separate sections in the final binary instead of merging
+  them as `.text`.
+
+* `-z rodynamic`:
+  Make the `.dynamic` section read-only.
+
+* `-z relro`, `-z norelro`:
+  Some sections such as `.dynamic` have to be writable only during a module is
+  being loaded to memory. Once the dynamic linker finishes its job, such
+  sections won't be mutated by anyone. As a security mitigation, it is
+  preferred to make such segments read-only during program execution.
+
+  `-z relro` puts such sections into a special segment called `relro`. The
+  dynamic linker makes a relro segment read-only after it finishes its job.
+
+  By default, `mold` generates a relro segment. `-z norelro` disables the
+  feature.
+
+* `-z sectionheader`, `-z nosectionheader`:
+  `-z nosectionheader` tell the linker to omit the section header.
+  By default, the linker does not omit the section header.
+
+* `-z separate-loadable-segments`, `-z separate-code`, `-z noseparate-code`:
+  If one memory page contains multiple segments, the page protection bits are
+  set in such a way that the needed attributes (writable or executable) are
+  satisfied for all segments. This usually happens at a boundary of two
+  segments with two different attributes.
+
+  `separate-loadable-segments` adds paddings between segments with different
+  attributes so that they do not share the same page.
+
+  `separate-code` adds paddings only between executable and non-executable
+  segments. This is the default.
+
+  `noseparate-code` does not add any paddings between segments.
+
+* `-z defs`, `-z nodefs`:
+  Report undefined symbols (even with `--shared`).
+
+* `-z shstk`:
+  Enforce shadow stack by turning `GNU_PROPERTY_X86_FEATURE_1_SHSTK` bit in
+  `.note.gnu.property` output section. Shadow stack is part of Intel
+  Control-flow Enforcement Technology (CET), which is available since Tiger
+  Lake (2020).
+
+* `-z start_stop_visibility`=[ `hidden` | `protected` ]:
+  If a section name is valid as a C identifier (i.e., it matches
+  `/^[_a-zA-Z][_a-zA-Z0-9]*$/`), mold creates `__start_SECNAME` and
+  `__stop_SECNAME` symbols to mark the beginning and end of the section,
+  where `SECNAME` is the section name.
+
+  You can make these marker symbols visible from other ELF modules by passing
+  `-z start_stop_visibility=protected`. Default is `hidden`.
+
+* `-z text`, `-z notext`, `-z textoff`:
+  `mold` by default reports an error if dynamic relocations are created in
+  read-only sections. If `-z notext` or `-z textoff` are given, `mold` creates
+  such dynamic relocations without reporting an error. `-z text` restores the
+  default behavior.
+
+* `-z max-page-size`=_number_:
+  Some CPU ISAs support multiple memory page sizes. This option specifies the
+  maximum page size that an output binary can run on. In general, binaries
+  built for a larger page size can run on a system with a smaller page size,
+  but not vice versa. The default value is 4 KiB for i386, x86-64, and RISC-V,
+  and 64 KiB for ARM64.
+
+* `-z nodefaultlib`:
+  Make the dynamic loader ignore default search paths.
+
+* `-z nodelete`:
+  Mark DSO non-deletable at runtime.
+
+* `-z nodlopen`:
+  Mark DSO not available to dlopen(3). This option makes it possible for the
+  linker to optimize thread-local variable accesses by rewriting instructions
+  for some targets.
+
+* `-z nodump`:
+  Mark DSO not available to dldump(3).
+
+* `-z nocopyreloc`:
+  Do not create copy relocations.
+
+* `-z initfirst`:
+  Mark DSO to be initialized first at runtime.
+
+* `-z interpose`:
+  Mark object to interpose all DSOs but executable.
+
+* `-(`, `-)`, `-EL`, `-O`_number_, `--dc`, `--dp`, `--end-group`, `--no-add-needed`, `--no-copy-dt-needed-entries`, `--nostdlib`, `--rpath-link=Ar dir`, `--sort-common`, `--sort-section`, `--start-group`, `--warn-constructors`, `--warn-once`, `--fix-cortex-a53-835769`, `--fix-cortex-a53-843419`, `-z combreloc`, `-z common-page-size`, `-z nocombreloc`:
+  Ignored
+
+## ENVIRONMENT VARIABLES
+
+* `MOLD_JOBS`:
+  If this variable is set to `1`, only one `mold` process will run at a time.
+  If a new mold process is initiated while another is already active, the new
+  process will wait until the active one completes before starting.
+
+  The primary reason for this environment variable is to minimize peak memory
+  usage. Since mold is designed to operate with high parallelism, running
+  multiple mold instances simultaneously may not be beneficial. If you execute
+  N instances of mold concurrently, it could require N times the time and N
+  times the memory. On the other hand, running them one after the other might
+  still take N times longer, but the peak memory usage would be the same as
+  running just a single instance.
+
+  If your build system invokes multiple linker processes simultaneously and
+  some of them often get killed due to out-of-memory errors, you might
+  consider setting this environment variable to `1` to see if it addresses the
+  OOM issue.
+
+  Currently, any value other than `1` is silently ignored.
+
+* `MOLD_DEBUG`:
+  If this variable is set to a non-empty string, `mold` embeds its
+  command-line options in the output file's `.comment` section.
+
+* `MOLD_REPRO`:
+  Setting this variable to a non-empty string has the same effect as passing
+  the `--repro` option.
+
+## SEE ALSO
+
+gold(1), ld(1), elf(5), ld.so(8)
+
+## AUTHOR
+
+Rui Ueyama <ruiu@cs.stanford.edu>
+
+## BUGS
+
+Report bugs to <https://github.com/rui314/mold/issues>.

elf/arch-alpha.cc

@@ -1,342 +0,0 @@
-// Alpha is a 64-bit RISC ISA developed by DEC (Digital Equipment
-// Corporation) in the early '90s. It aimed to be an ISA that would last
-// 25 years. DEC expected Alpha would become 1000x faster during that time
-// span. Since the ISA was developed from scratch for future machines,
-// it's 64-bit from the beginning. There's no 32-bit variant.
-//
-// DEC ported its own Unix (Tru64) to Alpha. Microsoft also ported Windows
-// NT to it. But it wasn't a huge commercial success.
-//
-// DEC was acquired by Compaq in 1997. In the late '90s, Intel and
-// Hewlett-Packard were advertising that their upcoming Itanium processor
-// would achieve significantly better performance than RISC processors, so
-// Compaq decided to discontinue the Alpha processor line to switch to
-// Itanium. Itanium resulted in a miserable failure, but it still suceeded
-// to wipe out several RISC processors just by promising overly optimistic
-// perf numbers. Alpha as an ISA would probably have been fine after 25
-// years since its introduction (which is 1992 + 25 = 2017), but the
-// company and its market didn't last that long.
-//
-// From the linker's point of view, there are a few peculiarities in its
-// psABI as shown below:
-//
-//  - Alpha lacks PC-relative memory load/store instructions, so it uses
-//    register-relative load/store instructions in position-independent
-//    code. Specifically, GP (which is an alias for $r29) is always
-//    maintained to refer to .got+0x8000, and global variables' addresses
-//    are loaded in a GP-relative manner.
-//
-//  - It looks like even function addresses are first loaded to register
-//    in a GP-relative manner before calling it. We can relax it to
-//    convert the instruction sequence with a direct branch instruction,
-//    but by default, object files don't use a direct branch to call a
-//    function. Therefore, by default, we don't need to create a PLT.
-//    Any function call is made by first reading its address from GOT and
-//    jump to the address.
-
-#include "mold.h"
-
-namespace mold::elf {
-
-using E = ALPHA;
-
-// A 32-bit immediate can be materialized in a register with a "load high"
-// and a "load low" instruction sequence. The first instruction sets the
-// upper 16 bits in a register, and the second one set the lower 16
-// bits. When doing so, they sign-extend an immediate.  Therefore, if the
-// 15th bit of an immediate happens to be 1, setting a "low half" value
-// negates the upper 16 bit values that has already been set in a
-// register. To compensate that, we need to add 0x8000 when setting the
-// upper 16 bits.
-static u32 hi(u32 val) {
-  return bits(val + 0x8000, 31, 16);
-}
-
-template <>
-void write_plt_header(Context<E> &ctx, u8 *buf) {}
-
-template <>
-void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {}
-
-template <>
-void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {}
-
-template <>
-void EhFrameSection<E>::apply_reloc(Context<E> &ctx, const ElfRel<E> &rel,
-                                    u64 offset, u64 val) {
-  u8 *loc = ctx.buf + this->shdr.sh_offset + offset;
-
-  switch (rel.r_type) {
-  case R_NONE:
-    break;
-  case R_ALPHA_SREL32:
-    *(ul32 *)loc = val - this->shdr.sh_addr - offset;
-    break;
-  default:
-    Fatal(ctx) << "unsupported relocation in .eh_frame: " << rel;
-  }
-}
-
-template <>
-void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-
-  ElfRel<E> *dynrel = nullptr;
-  if (ctx.reldyn)
-    dynrel = (ElfRel<E> *)(ctx.buf + ctx.reldyn->shdr.sh_offset +
-                           file.reldyn_offset + this->reldyn_offset);
-
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
-      continue;
-
-    Symbol<E> &sym = *file.symbols[rel.r_sym];
-    u8 *loc = base + rel.r_offset;
-
-    u64 S = sym.get_addr(ctx);
-    u64 A = rel.r_addend;
-    u64 P = get_addr() + rel.r_offset;
-    u64 G = sym.get_got_idx(ctx) * sizeof(Word<E>);
-    u64 GOT = ctx.got->shdr.sh_addr;
-    u64 GP = ctx.got->shdr.sh_addr + 0x8000;
-
-    switch (rel.r_type) {
-    case R_ALPHA_REFQUAD:
-      apply_dyn_absrel(ctx, sym, rel, loc, S, A, P, dynrel);
-      break;
-    case R_ALPHA_GPREL32:
-      *(ul32 *)loc = S + A - GP;
-      break;
-    case R_ALPHA_LITERAL:
-      if (A)
-        *(ul16 *)loc = ctx.extra.got->get_addr(sym, A) - GP;
-      else
-        *(ul16 *)loc = GOT + G - GP;
-      break;
-    case R_ALPHA_BRSGP:
-      *(ul32 *)loc |= bits(S + A - P - 4, 22, 0);
-      break;
-    case R_ALPHA_GPDISP:
-      *(ul16 *)loc = hi(GP - P);
-      *(ul16 *)(loc + A) = GP - P;
-      break;
-    case R_ALPHA_SREL32:
-      *(ul32 *)loc = S + A - P;
-      break;
-    case R_ALPHA_GPRELHIGH:
-      *(ul16 *)loc = hi(S + A - GP);
-      break;
-    case R_ALPHA_GPRELLOW:
-      *(ul16 *)loc = S + A - GP;
-      break;
-    case R_ALPHA_TLSGD:
-      *(ul16 *)loc = sym.get_tlsgd_addr(ctx) - GP;
-      break;
-    case R_ALPHA_TLSLDM:
-      *(ul16 *)loc = ctx.got->get_tlsld_addr(ctx) - GP;
-      break;
-    case R_ALPHA_DTPRELHI:
-      *(ul16 *)loc = hi(S + A - ctx.dtp_addr);
-      break;
-    case R_ALPHA_DTPRELLO:
-      *(ul16 *)loc = S + A - ctx.dtp_addr;
-      break;
-    case R_ALPHA_GOTTPREL:
-      *(ul16 *)loc = sym.get_gottp_addr(ctx) + A - GP;
-      break;
-    case R_ALPHA_TPRELHI:
-      *(ul16 *)loc = hi(S + A - ctx.tp_addr);
-      break;
-    case R_ALPHA_TPRELLO:
-      *(ul16 *)loc = S + A - ctx.tp_addr;
-      break;
-    case R_ALPHA_LITUSE:
-    case R_ALPHA_HINT:
-      break;
-    default:
-      unreachable();
-    }
-  }
-}
-
-template <>
-void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
-      continue;
-
-    Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-    u8 *loc = base + rel.r_offset;
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
-    SectionFragment<E> *frag;
-    i64 frag_addend;
-    std::tie(frag, frag_addend) = get_fragment(ctx, rel);
-
-    u64 S = frag ? frag->get_addr(ctx) : sym.get_addr(ctx);
-    u64 A = frag ? frag_addend : (i64)rel.r_addend;
-
-    switch (rel.r_type) {
-    case R_ALPHA_REFLONG:
-      if (std::optional<u64> val = get_tombstone(sym, frag))
-        *(ul32 *)loc = *val;
-      else
-        *(ul32 *)loc = S + A;
-      break;
-    case R_ALPHA_REFQUAD:
-      if (std::optional<u64> val = get_tombstone(sym, frag))
-        *(ul64 *)loc = *val;
-      else
-        *(ul64 *)loc = S + A;
-      break;
-    default:
-      Fatal(ctx) << *this << ": invalid relocation for non-allocated sections: "
-                 << rel;
-    }
-  }
-}
-
-template <>
-void InputSection<E>::scan_relocations(Context<E> &ctx) {
-  assert(shdr().sh_flags & SHF_ALLOC);
-
-  this->reldyn_offset = file.num_dynrel * sizeof(ElfRel<E>);
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
-      continue;
-
-    Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
-    if (sym.is_ifunc())
-      Error(ctx) << sym << ": GNU ifunc symbol is not supported on Alpha";
-
-    switch (rel.r_type) {
-    case R_ALPHA_REFQUAD:
-      scan_dyn_absrel(ctx, sym, rel);
-      break;
-    case R_ALPHA_LITERAL:
-      if (rel.r_addend)
-        ctx.extra.got->add_symbol(sym, rel.r_addend);
-      else
-        sym.flags |= NEEDS_GOT;
-      break;
-    case R_ALPHA_SREL32:
-      scan_pcrel(ctx, sym, rel);
-      break;
-    case R_ALPHA_BRSGP:
-      if (sym.is_imported)
-        sym.flags |= NEEDS_PLT;
-      break;
-    case R_ALPHA_TLSGD:
-      sym.flags |= NEEDS_TLSGD;
-      break;
-    case R_ALPHA_TLSLDM:
-      ctx.needs_tlsld = true;
-      break;
-    case R_ALPHA_GOTTPREL:
-      sym.flags |= NEEDS_GOTTP;
-      break;
-    case R_ALPHA_TPRELHI:
-    case R_ALPHA_TPRELLO:
-      check_tlsle(ctx, sym, rel);
-      break;
-    case R_ALPHA_GPREL32:
-    case R_ALPHA_LITUSE:
-    case R_ALPHA_GPDISP:
-    case R_ALPHA_HINT:
-    case R_ALPHA_GPRELHIGH:
-    case R_ALPHA_GPRELLOW:
-    case R_ALPHA_DTPRELHI:
-    case R_ALPHA_DTPRELLO:
-      break;
-    default:
-      Fatal(ctx) << *this << ": unknown relocation: " << rel;
-    }
-  }
-}
-
-// An R_ALPHA_LITERAL relocation may request the linker to create a GOT
-// entry for an external symbol with a non-zero addend. This is an unusual
-// request which is not found in any other targets.
-//
-// Referring an external symbol with a non-zero addend is a bad practice
-// because we need to create as many dynamic relocations as the number of
-// distinctive addends for the same symbol.
-//
-// We don't want to mess up the implementation of the common GOT section
-// for Alpha. So we create another GOT-like section, .alpha_got. Any GOT
-// entry for an R_ALPHA_LITERAL reloc with a non-zero addend is created
-// not in .got but in .alpha_got.
-//
-// Since .alpha_got entries are accessed relative to GP, .alpha_got
-// needs to be close enough to .got. It's actually placed next to .got.
-void AlphaGotSection::add_symbol(Symbol<E> &sym, i64 addend) {
-  assert(addend);
-  std::scoped_lock lock(mu);
-  entries.push_back({&sym, addend});
-}
-
-bool operator<(const AlphaGotSection::Entry &a, const AlphaGotSection::Entry &b) {
-  return std::tuple(a.sym->file->priority, a.sym->sym_idx, a.addend) <
-         std::tuple(b.sym->file->priority, b.sym->sym_idx, b.addend);
-};
-
-u64 AlphaGotSection::get_addr(Symbol<E> &sym, i64 addend) {
-  auto it = std::lower_bound(entries.begin(), entries.end(), Entry{&sym, addend});
-  assert(it != entries.end());
-  return this->shdr.sh_addr + (it - entries.begin()) * sizeof(Word<E>);
-}
-
-i64 AlphaGotSection::get_reldyn_size(Context<E> &ctx) const {
-  i64 n = 0;
-  for (const Entry &e : entries)
-    if (e.sym->is_imported || (ctx.arg.pic && !e.sym->is_absolute()))
-      n++;
-  return n;
-}
-
-void AlphaGotSection::finalize() {
-  sort(entries);
-  remove_duplicates(entries);
-  shdr.sh_size = entries.size() * sizeof(Word<E>);
-}
-
-void AlphaGotSection::copy_buf(Context<E> &ctx) {
-  ElfRel<E> *dynrel = (ElfRel<E> *)(ctx.buf + ctx.reldyn->shdr.sh_offset +
-                                    reldyn_offset);
-
-  for (i64 i = 0; i < entries.size(); i++) {
-    Entry &e = entries[i];
-    u64 P = this->shdr.sh_addr + sizeof(Word<E>) * i;
-    ul64 *buf = (ul64 *)(ctx.buf + this->shdr.sh_offset + sizeof(Word<E>) * i);
-
-    if (e.sym->is_imported) {
-      *buf = ctx.arg.apply_dynamic_relocs ? e.addend : 0;
-      *dynrel++ = ElfRel<E>(P, E::R_ABS, e.sym->get_dynsym_idx(ctx), e.addend);
-    } else {
-      *buf = e.sym->get_addr(ctx) + e.addend;
-      if (ctx.arg.pic && !e.sym->is_absolute())
-        *dynrel++ = ElfRel<E>(P, E::R_RELATIVE, 0, *buf);
-    }
-  }
-}
-
-} // namespace mold::elf

elf/arch-arm32.cc

@@ -1,748 +0,0 @@
-// ARM32 is a bit special from the linker's viewpoint because ARM
-// processors support two different instruction encodings: Thumb and
-// ARM (in a narrower sense). Thumb instructions are either 16 bits or
-// 32 bits, while ARM instructions are all 32 bits. Feature-wise,
-// thumb is a subset of ARM, so not all ARM instructions are
-// representable in Thumb.
-//
-// ARM processors originally supported only ARM instructions. Thumb
-// instructions were later added to increase code density.
-//
-// ARM processors runs in either ARM mode or Thumb mode. The mode can
-// be switched using BX (branch and mode exchange)-family instructions.
-// We need to use that instructions to, for example, call a function
-// encoded in Thumb from a function encoded in ARM. Sometimes, the
-// linker even has to emit an interworking thunk code to switch mode.
-//
-// ARM instructions are aligned to 4 byte boundaries. Thumb are to 2
-// byte boundaries.
-//
-// You can distinguish Thumb functions from ARM functions by looking
-// at the least significant bit (LSB) of its "address". If LSB is 0,
-// it's ARM; otherwise, Thumb.
-//
-// For example, if a symbol `foo` is of type STT_FUNC and has value
-// 0x2001, `foo` is a function using Thumb instructions whose address
-// is 0x2000 (not 0x2001, as Thumb instructions are always 2-byte
-// aligned). Likewise, if a function pointer has value 0x2001, it
-// refers a Thumb function at 0x2000.
-//
-// https://github.com/ARM-software/abi-aa/blob/main/aaelf32/aaelf32.rst
-
-#include "mold.h"
-
-#include <tbb/parallel_for.h>
-#include <tbb/parallel_for_each.h>
-#include <tbb/parallel_sort.h>
-
-namespace mold::elf {
-
-using E = ARM32;
-
-template <>
-i64 get_addend(u8 *loc, const ElfRel<E> &rel) {
-  switch (rel.r_type) {
-  case R_ARM_ABS32:
-  case R_ARM_REL32:
-  case R_ARM_TARGET1:
-  case R_ARM_BASE_PREL:
-  case R_ARM_GOTOFF32:
-  case R_ARM_GOT_PREL:
-  case R_ARM_GOT_BREL:
-  case R_ARM_TLS_GD32:
-  case R_ARM_TLS_LDM32:
-  case R_ARM_TLS_LDO32:
-  case R_ARM_TLS_IE32:
-  case R_ARM_TLS_LE32:
-  case R_ARM_TLS_GOTDESC:
-  case R_ARM_TARGET2:
-    return *(il32 *)loc;
-  case R_ARM_THM_JUMP11:
-    return sign_extend(*(ul16 *)loc, 10) << 1;
-  case R_ARM_THM_CALL:
-  case R_ARM_THM_JUMP24:
-  case R_ARM_THM_TLS_CALL: {
-    u32 S = bit(*(ul16 *)loc, 10);
-    u32 J1 = bit(*(ul16 *)(loc + 2), 13);
-    u32 J2 = bit(*(ul16 *)(loc + 2), 11);
-    u32 I1 = !(J1 ^ S);
-    u32 I2 = !(J2 ^ S);
-    u32 imm10 = bits(*(ul16 *)loc, 9, 0);
-    u32 imm11 = bits(*(ul16 *)(loc + 2), 10, 0);
-    u32 val = (S << 24) | (I1 << 23) | (I2 << 22) | (imm10 << 12) | (imm11 << 1);
-    return sign_extend(val, 24);
-  }
-  case R_ARM_CALL:
-  case R_ARM_JUMP24:
-  case R_ARM_PLT32:
-  case R_ARM_TLS_CALL:
-    return sign_extend(*(ul32 *)loc, 23) << 2;
-  case R_ARM_MOVW_PREL_NC:
-  case R_ARM_MOVW_ABS_NC:
-  case R_ARM_MOVT_PREL:
-  case R_ARM_MOVT_ABS: {
-    u32 imm12 = bits(*(ul32 *)loc, 11, 0);
-    u32 imm4 = bits(*(ul32 *)loc, 19, 16);
-    return sign_extend((imm4 << 12) | imm12, 15);
-  }
-  case R_ARM_PREL31:
-    return sign_extend(*(ul32 *)loc, 30);
-  case R_ARM_THM_MOVW_PREL_NC:
-  case R_ARM_THM_MOVW_ABS_NC:
-  case R_ARM_THM_MOVT_PREL:
-  case R_ARM_THM_MOVT_ABS: {
-    u32 imm4 = bits(*(ul16 *)loc, 3, 0);
-    u32 i = bit(*(ul16 *)loc, 10);
-    u32 imm3 = bits(*(ul16 *)(loc + 2), 14, 12);
-    u32 imm8 = bits(*(ul16 *)(loc + 2), 7, 0);
-    u32 val = (imm4 << 12) | (i << 11) | (imm3 << 8) | imm8;
-    return sign_extend(val, 15);
-  }
-  default:
-    return 0;
-  }
-}
-
-static void write_mov_imm(u8 *loc, u32 val) {
-  u32 imm12 = bits(val, 11, 0);
-  u32 imm4 = bits(val, 15, 12);
-  *(ul32 *)loc = (*(ul32 *)loc & 0xfff0f000) | (imm4 << 16) | imm12;
-}
-
-static void write_thm_b_imm(u8 *loc, u32 val) {
-  // https://developer.arm.com/documentation/ddi0406/cb/Application-Level-Architecture/Instruction-Details/Alphabetical-list-of-instructions/BL--BLX--immediate-
-  u32 sign = bit(val, 24);
-  u32 I1 = bit(val, 23);
-  u32 I2 = bit(val, 22);
-  u32 J1 = !I1 ^ sign;
-  u32 J2 = !I2 ^ sign;
-  u32 imm10 = bits(val, 21, 12);
-  u32 imm11 = bits(val, 11, 1);
-
-  ul16 *buf = (ul16 *)loc;
-  buf[0] = (buf[0] & 0b1111'1000'0000'0000) | (sign << 10) | imm10;
-  buf[1] = (buf[1] & 0b1101'0000'0000'0000) | (J1 << 13) | (J2 << 11) | imm11;
-}
-
-static void write_thm_mov_imm(u8 *loc, u32 val) {
-  // https://developer.arm.com/documentation/ddi0406/cb/Application-Level-Architecture/Instruction-Details/Alphabetical-list-of-instructions/MOVT
-  u32 imm4 = bits(val, 15, 12);
-  u32 i = bit(val, 11);
-  u32 imm3 = bits(val, 10, 8);
-  u32 imm8 = bits(val, 7, 0);
-
-  ul16 *buf = (ul16 *)loc;
-  buf[0] = (buf[0] & 0b1111'1011'1111'0000) | (i << 10) | imm4;
-  buf[1] = (buf[1] & 0b1000'1111'0000'0000) | (imm3 << 12) | imm8;
-}
-
-template <>
-void write_addend(u8 *loc, i64 val, const ElfRel<E> &rel) {
-  switch (rel.r_type) {
-  case R_ARM_NONE:
-    break;
-  case R_ARM_ABS32:
-  case R_ARM_REL32:
-  case R_ARM_TARGET1:
-  case R_ARM_BASE_PREL:
-  case R_ARM_GOTOFF32:
-  case R_ARM_GOT_PREL:
-  case R_ARM_GOT_BREL:
-  case R_ARM_TLS_GD32:
-  case R_ARM_TLS_LDM32:
-  case R_ARM_TLS_LDO32:
-  case R_ARM_TLS_IE32:
-  case R_ARM_TLS_LE32:
-  case R_ARM_TLS_GOTDESC:
-  case R_ARM_TARGET2:
-    *(ul32 *)loc = val;
-    break;
-  case R_ARM_THM_JUMP11:
-    *(ul16 *)loc = (*(ul16 *)loc & 0xf800) | bits(val, 11, 1);
-    break;
-  case R_ARM_THM_CALL:
-  case R_ARM_THM_JUMP24:
-  case R_ARM_THM_TLS_CALL:
-    write_thm_b_imm(loc, val);
-    break;
-  case R_ARM_CALL:
-  case R_ARM_JUMP24:
-  case R_ARM_PLT32:
-    *(ul32 *)loc = (*(ul32 *)loc & 0xff00'0000) | bits(val, 25, 2);
-    break;
-  case R_ARM_MOVW_PREL_NC:
-  case R_ARM_MOVW_ABS_NC:
-  case R_ARM_MOVT_PREL:
-  case R_ARM_MOVT_ABS:
-    write_mov_imm(loc, val);
-    break;
-  case R_ARM_PREL31:
-    *(ul32 *)loc = (*(ul32 *)loc & 0x8000'0000) | (val & 0x7fff'ffff);
-    break;
-  case R_ARM_THM_MOVW_PREL_NC:
-  case R_ARM_THM_MOVW_ABS_NC:
-  case R_ARM_THM_MOVT_PREL:
-  case R_ARM_THM_MOVT_ABS:
-    write_thm_mov_imm(loc, val);
-    break;
-  default:
-    unreachable();
-  }
-}
-
-template <>
-void write_plt_header(Context<E> &ctx, u8 *buf) {
-  static const ul32 insn[] = {
-    0xe52d'e004, // push {lr}
-    0xe59f'e004, // ldr lr, 2f
-    0xe08f'e00e, // 1: add lr, pc, lr
-    0xe5be'f008, // ldr pc, [lr, #8]!
-    0x0000'0000, // 2: .word .got.plt - 1b - 8
-    0xe320'f000, // nop
-    0xe320'f000, // nop
-    0xe320'f000, // nop
-  };
-
-  memcpy(buf, insn, sizeof(insn));
-  *(ul32 *)(buf + 16) = ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 16;
-}
-
-static const ul32 plt_entry[] = {
-  0xe59f'c004, // 1: ldr ip, 2f
-  0xe08c'c00f, // add ip, ip, pc
-  0xe59c'f000, // ldr pc, [ip]
-  0x0000'0000, // 2: .word sym@GOT - 1b
-};
-
-template <>
-void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
-  memcpy(buf, plt_entry, sizeof(plt_entry));
-  *(ul32 *)(buf + 12) = sym.get_gotplt_addr(ctx) - sym.get_plt_addr(ctx) - 12;
-}
-
-template <>
-void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
-  memcpy(buf, plt_entry, sizeof(plt_entry));
-  *(ul32 *)(buf + 12) = sym.get_got_addr(ctx) - sym.get_plt_addr(ctx) - 12;
-}
-
-// ARM does not use .eh_frame for exception handling. Instead, it uses
-// .ARM.exidx and .ARM.extab. So this function is empty.
-template <>
-void EhFrameSection<E>::apply_reloc(Context<E> &ctx, const ElfRel<E> &rel,
-                                    u64 offset, u64 val) {}
-
-// ARM and Thumb branch instructions can jump within ±16 MiB.
-static bool is_jump_reachable(i64 val) {
-  return sign_extend(val, 24) == val;
-}
-
-template <>
-void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-
-  ElfRel<E> *dynrel = nullptr;
-  if (ctx.reldyn)
-    dynrel = (ElfRel<E> *)(ctx.buf + ctx.reldyn->shdr.sh_offset +
-                           file.reldyn_offset + this->reldyn_offset);
-
-  std::span<std::unique_ptr<RangeExtensionThunk<E>>> thunks =
-    output_section->thunks;
-
-  auto get_tls_trampoline_addr = [&](u64 addr) {
-    for (;;) {
-      assert(!thunks.empty());
-      i64 disp = output_section->shdr.sh_addr + thunks[0]->offset - addr;
-      if (is_jump_reachable(disp))
-        return disp;
-      thunks = thunks.subspan(1);
-    }
-  };
-
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE || rel.r_type == R_ARM_V4BX)
-      continue;
-
-    Symbol<E> &sym = *file.symbols[rel.r_sym];
-    u8 *loc = base + rel.r_offset;
-
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
-    u64 S = sym.get_addr(ctx);
-    u64 A = get_addend(*this, rel);
-    u64 P = get_addr() + rel.r_offset;
-    u64 T = S & 1;
-    u64 G = sym.get_got_idx(ctx) * sizeof(Word<E>);
-    u64 GOT = ctx.got->shdr.sh_addr;
-
-    auto get_thumb_thunk_addr = [&] { return get_thunk_addr(i); };
-    auto get_arm_thunk_addr   = [&] { return get_thunk_addr(i) + 4; };
-
-    switch (rel.r_type) {
-    case R_ARM_ABS32:
-    case R_ARM_TARGET1:
-      apply_dyn_absrel(ctx, sym, rel, loc, S, A, P, dynrel);
-      break;
-    case R_ARM_REL32:
-      *(ul32 *)loc = S + A - P;
-      break;
-    case R_ARM_THM_CALL: {
-      if (sym.is_remaining_undef_weak()) {
-        // On ARM, calling an weak undefined symbol jumps to the
-        // next instruction.
-        *(ul32 *)loc = 0x8000'f3af; // NOP.W
-        break;
-      }
-
-      // THM_CALL relocation refers either BL or BLX instruction.
-      // They are different in only one bit. We need to use BL if
-      // the jump target is Thumb. Otherwise, use BLX.
-      i64 val = S + A - P;
-      if (is_jump_reachable(val)) {
-        if (T) {
-          write_thm_b_imm(loc, val);
-          *(ul16 *)(loc + 2) |= 0x1000;  // rewrite to BL
-        } else {
-          write_thm_b_imm(loc, align_to(val, 4));
-          *(ul16 *)(loc + 2) &= ~0x1000; // rewrite to BLX
-        }
-      } else {
-        write_thm_b_imm(loc, align_to(get_arm_thunk_addr() + A - P, 4));
-        *(ul16 *)(loc + 2) &= ~0x1000;  // rewrite to BLX
-      }
-      break;
-    }
-    case R_ARM_BASE_PREL:
-      *(ul32 *)loc = GOT + A - P;
-      break;
-    case R_ARM_GOTOFF32:
-      *(ul32 *)loc = ((S + A) | T) - GOT;
-      break;
-    case R_ARM_GOT_PREL:
-    case R_ARM_TARGET2:
-      *(ul32 *)loc = GOT + G + A - P;
-      break;
-    case R_ARM_GOT_BREL:
-      *(ul32 *)loc = G + A;
-      break;
-    case R_ARM_CALL: {
-      if (sym.is_remaining_undef_weak()) {
-        *(ul32 *)loc = 0xe320'f000; // NOP
-        break;
-      }
-
-      // Just like THM_CALL, ARM_CALL relocation refers either BL or
-      // BLX instruction. We may need to rewrite BL → BLX or BLX → BL.
-      bool is_bl = ((*(ul32 *)loc & 0xff00'0000) == 0xeb00'0000);
-      bool is_blx = ((*(ul32 *)loc & 0xfe00'0000) == 0xfa00'0000);
-      if (!is_bl && !is_blx)
-        Fatal(ctx) << *this << ": R_ARM_CALL refers neither BL nor BLX";
-
-      u64 val = S + A - P;
-      if (is_jump_reachable(val)) {
-        if (T) {
-          *(ul32 *)loc = 0xfa00'0000; // BLX
-          *(ul32 *)loc |= (bit(val, 1) << 24) | bits(val, 25, 2);
-        } else {
-          *(ul32 *)loc = 0xeb00'0000; // BL
-          *(ul32 *)loc |= bits(val, 25, 2);
-        }
-      } else {
-        *(ul32 *)loc = 0xeb00'0000; // BL
-        *(ul32 *)loc |= bits(get_arm_thunk_addr() + A - P, 25, 2);
-      }
-      break;
-    }
-    case R_ARM_JUMP24:
-    case R_ARM_PLT32: {
-      if (sym.is_remaining_undef_weak()) {
-        *(ul32 *)loc = 0xe320'f000; // NOP
-        break;
-      }
-
-      // These relocs refers a B (unconditional branch) instruction.
-      // Unlike BL or BLX, we can't rewrite B to BX in place when the
-      // processor mode switch is required because BX doesn't takes an
-      // immediate; it takes only a register. So if mode switch is
-      // required, we jump to a linker-synthesized thunk which does the
-      // job with a longer code sequence.
-      u64 val = S + A - P;
-      if (!is_jump_reachable(val) || T)
-        val = get_arm_thunk_addr() + A - P;
-      *(ul32 *)loc = (*(ul32 *)loc & 0xff00'0000) | bits(val, 25, 2);
-      break;
-    }
-    case R_ARM_THM_JUMP11:
-      assert(T);
-      check(S + A - P, -(1 << 11), 1 << 11);
-      *(ul16 *)loc &= 0xf800;
-      *(ul16 *)loc |= bits(S + A - P, 11, 1);
-      break;
-    case R_ARM_THM_JUMP19: {
-      i64 val = S + A - P;
-      check(val, -(1 << 19), 1 << 19);
-
-      // sign:J2:J1:imm6:imm11:'0'
-      u32 sign = bit(val, 20);
-      u32 J2 = bit(val, 19);
-      u32 J1 = bit(val, 18);
-      u32 imm6 = bits(val, 17, 12);
-      u32 imm11 = bits(val, 11, 1);
-
-      *(ul16 *)loc &= 0b1111'1011'1100'0000;
-      *(ul16 *)loc |= (sign << 10) | imm6;
-
-      *(ul16 *)(loc + 2) &= 0b1101'0000'0000'0000;
-      *(ul16 *)(loc + 2) |= (J2 << 13) | (J1 << 11) | imm11;
-      break;
-    }
-    case R_ARM_THM_JUMP24: {
-      if (sym.is_remaining_undef_weak()) {
-        *(ul32 *)loc = 0x8000'f3af; // NOP
-        break;
-      }
-
-      // Just like R_ARM_JUMP24, we need to jump to a thunk if we need to
-      // switch processor mode.
-      u64 val = S + A - P;
-      if (!is_jump_reachable(val) || !T)
-        val = get_thumb_thunk_addr() + A - P;
-      write_thm_b_imm(loc, val);
-      break;
-    }
-    case R_ARM_MOVW_PREL_NC:
-      write_mov_imm(loc, ((S + A) | T) - P);
-      break;
-    case R_ARM_MOVW_ABS_NC:
-      write_mov_imm(loc, (S + A) | T);
-      break;
-    case R_ARM_THM_MOVW_PREL_NC:
-      write_thm_mov_imm(loc, ((S + A) | T) - P);
-      break;
-    case R_ARM_PREL31:
-      check(S + A - P, -(1LL << 30), 1LL << 30);
-      *(ul32 *)loc &= 0x8000'0000;
-      *(ul32 *)loc |= (S + A - P) & 0x7fff'ffff;
-      break;
-    case R_ARM_THM_MOVW_ABS_NC:
-      write_thm_mov_imm(loc, (S + A) | T);
-      break;
-    case R_ARM_MOVT_PREL:
-      write_mov_imm(loc, (S + A - P) >> 16);
-      break;
-    case R_ARM_THM_MOVT_PREL:
-      write_thm_mov_imm(loc, (S + A - P) >> 16);
-      break;
-    case R_ARM_MOVT_ABS:
-      write_mov_imm(loc, (S + A) >> 16);
-      break;
-    case R_ARM_THM_MOVT_ABS:
-      write_thm_mov_imm(loc, (S + A) >> 16);
-      break;
-    case R_ARM_TLS_GD32:
-      *(ul32 *)loc = sym.get_tlsgd_addr(ctx) + A - P;
-      break;
-    case R_ARM_TLS_LDM32:
-      *(ul32 *)loc = ctx.got->get_tlsld_addr(ctx) + A - P;
-      break;
-    case R_ARM_TLS_LDO32:
-      *(ul32 *)loc = S + A - ctx.dtp_addr;
-      break;
-    case R_ARM_TLS_IE32:
-      *(ul32 *)loc = sym.get_gottp_addr(ctx) + A - P;
-      break;
-    case R_ARM_TLS_LE32:
-      *(ul32 *)loc = S + A - ctx.tp_addr;
-      break;
-    case R_ARM_TLS_GOTDESC:
-      if (sym.has_tlsdesc(ctx)) {
-        // A is odd if the corresponding TLS_CALL is Thumb.
-        if (A & 1)
-          *(ul32 *)loc = sym.get_tlsdesc_addr(ctx) - P + A - 6;
-        else
-          *(ul32 *)loc = sym.get_tlsdesc_addr(ctx) - P + A - 4;
-      } else {
-        *(ul32 *)loc = S - ctx.tp_addr;
-      }
-      break;
-    case R_ARM_TLS_CALL:
-      if (sym.has_tlsdesc(ctx)) {
-        // BL <tls_trampoline>
-        *(ul32 *)loc = 0xeb00'0000 | bits(get_tls_trampoline_addr(P + 8), 25, 2);
-      } else {
-        // BL -> NOP
-        *(ul32 *)loc = 0xe320'f000;
-      }
-      break;
-    case R_ARM_THM_TLS_CALL:
-      if (sym.has_tlsdesc(ctx)) {
-        u64 val = align_to(get_tls_trampoline_addr(P + 4), 4);
-        write_thm_b_imm(loc, val);
-        *(ul16 *)(loc + 2) &= ~0x1000; // rewrite BL with BLX
-      } else {
-        // BL -> NOP.W
-        *(ul32 *)loc = 0x8000'f3af;
-      }
-      break;
-    default:
-      Error(ctx) << *this << ": unknown relocation: " << rel;
-    }
-  }
-}
-
-template <>
-void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
-      continue;
-
-    Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-    u8 *loc = base + rel.r_offset;
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
-    SectionFragment<E> *frag;
-    i64 frag_addend;
-    std::tie(frag, frag_addend) = get_fragment(ctx, rel);
-
-    u64 S = frag ? frag->get_addr(ctx) : sym.get_addr(ctx);
-    u64 A = frag ? frag_addend : get_addend(*this, rel);
-
-    switch (rel.r_type) {
-    case R_ARM_ABS32:
-      if (std::optional<u64> val = get_tombstone(sym, frag))
-        *(ul32 *)loc = *val;
-      else
-        *(ul32 *)loc = S + A;
-      break;
-    case R_ARM_TLS_LDO32:
-      if (std::optional<u64> val = get_tombstone(sym, frag))
-        *(ul32 *)loc = *val;
-      else
-        *(ul32 *)loc = S + A - ctx.dtp_addr;
-      break;
-    default:
-      Fatal(ctx) << *this << ": invalid relocation for non-allocated sections: "
-                 << rel;
-      break;
-    }
-  }
-}
-
-template <>
-void InputSection<E>::scan_relocations(Context<E> &ctx) {
-  assert(shdr().sh_flags & SHF_ALLOC);
-
-  this->reldyn_offset = file.num_dynrel * sizeof(ElfRel<E>);
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-
-  // Scan relocations
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
-      continue;
-
-    Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
-    if (sym.is_ifunc())
-      sym.flags |= NEEDS_GOT | NEEDS_PLT;
-
-    switch (rel.r_type) {
-    case R_ARM_ABS32:
-    case R_ARM_MOVT_ABS:
-    case R_ARM_THM_MOVT_ABS:
-    case R_ARM_TARGET1:
-      scan_dyn_absrel(ctx, sym, rel);
-      break;
-    case R_ARM_THM_CALL:
-    case R_ARM_CALL:
-    case R_ARM_JUMP24:
-    case R_ARM_PLT32:
-    case R_ARM_THM_JUMP24:
-      if (sym.is_imported)
-        sym.flags |= NEEDS_PLT;
-      break;
-    case R_ARM_GOT_PREL:
-    case R_ARM_GOT_BREL:
-    case R_ARM_TARGET2:
-      sym.flags |= NEEDS_GOT;
-      break;
-    case R_ARM_MOVT_PREL:
-    case R_ARM_THM_MOVT_PREL:
-    case R_ARM_PREL31:
-      scan_pcrel(ctx, sym, rel);
-      break;
-    case R_ARM_TLS_GD32:
-      sym.flags |= NEEDS_TLSGD;
-      break;
-    case R_ARM_TLS_LDM32:
-      ctx.needs_tlsld = true;
-      break;
-    case R_ARM_TLS_IE32:
-      sym.flags |= NEEDS_GOTTP;
-      break;
-    case R_ARM_TLS_GOTDESC:
-      if (!relax_tlsdesc(ctx, sym))
-        sym.flags |= NEEDS_TLSDESC;
-      break;
-    case R_ARM_TLS_LE32:
-      check_tlsle(ctx, sym, rel);
-      break;
-    case R_ARM_REL32:
-    case R_ARM_BASE_PREL:
-    case R_ARM_GOTOFF32:
-    case R_ARM_THM_JUMP11:
-    case R_ARM_THM_JUMP19:
-    case R_ARM_MOVW_PREL_NC:
-    case R_ARM_MOVW_ABS_NC:
-    case R_ARM_THM_MOVW_PREL_NC:
-    case R_ARM_THM_MOVW_ABS_NC:
-    case R_ARM_TLS_LDO32:
-    case R_ARM_TLS_CALL:
-    case R_ARM_THM_TLS_CALL:
-    case R_ARM_V4BX:
-      break;
-    default:
-      Error(ctx) << *this << ": unknown relocation: " << rel;
-    }
-  }
-}
-
-template <>
-void RangeExtensionThunk<E>::copy_buf(Context<E> &ctx) {
-  u8 *buf = ctx.buf + output_section.shdr.sh_offset + offset;
-
-  // TLS trampoline code. ARM32's TLSDESC is designed so that this
-  // common piece of code is factored out from object files to reduce
-  // output size. Since no one provide, the linker has to synthesize it.
-  static ul32 hdr[] = {
-    0xe08e'0000, // add r0, lr, r0
-    0xe590'1004, // ldr r1, [r0, #4]
-    0xe12f'ff11, // bx  r1
-  };
-
-  // This is a range extension and mode switch thunk.
-  // It has two entry points: +0 for Thumb and +4 for ARM.
-  const u8 entry[] = {
-    // .thumb
-    0xfc, 0x46,             //    mov  ip, pc
-    0x60, 0x47,             //    bx   ip  # jumps to the following `ldr` insn
-    // .arm
-    0x04, 0xc0, 0x9f, 0xe5, //    ldr  ip, 2f
-    0x0f, 0xc0, 0x8c, 0xe0, // 1: add  ip, ip, pc
-    0x1c, 0xff, 0x2f, 0xe1, //    bx   ip
-    0x00, 0x00, 0x00, 0x00, // 2: .word sym - 1b
-  };
-
-  static_assert(E::thunk_hdr_size == sizeof(hdr));
-  static_assert(E::thunk_size == sizeof(entry));
-
-  memcpy(buf, hdr, sizeof(hdr));
-
-  for (i64 i = 0; i < symbols.size(); i++) {
-    u8 *loc = buf + sizeof(hdr) + i * sizeof(entry);
-    memcpy(loc, entry, sizeof(entry));
-
-    u64 S = symbols[i]->get_addr(ctx);
-    u64 P = output_section.shdr.sh_addr + offset + sizeof(hdr) + i * sizeof(entry);
-    *(ul32 *)(loc + 16) = S - P - 16;
-  }
-}
-
-// ARM executables use an .ARM.exidx section to look up an exception
-// handling record for the current instruction pointer. The table needs
-// to be sorted by their addresses.
-//
-// Other target uses .eh_frame_hdr instead for the same purpose.
-// I don't know why only ARM uses the different mechanism, but it's
-// likely that it's due to some historical reason.
-//
-// This function sorts .ARM.exidx records.
-void fixup_arm_exidx_section(Context<E> &ctx) {
-  Timer t(ctx, "fixup_arm_exidx_section");
-
-  OutputSection<E> *osec = find_section(ctx, SHT_ARM_EXIDX);
-  if (!osec)
-    return;
-
-  // .ARM.exidx records consists of a signed 31-bit relative address
-  // and a 32-bit value. The relative address indicates the start
-  // address of a function that the record covers. The value is one of
-  // the followings:
-  //
-  // 1. CANTUNWIND indicating that there's no unwinding info for the function,
-  // 2. a compact unwinding record encoded into a 32-bit value, or
-  // 3. a 31-bit relative address which points to a larger record in
-  //    the .ARM.extab section.
-  //
-  // CANTUNWIND is value 1. The most significant bit is set in (2) but
-  // not in (3). So we can distinguished them just by looking at a value.
-  const u32 EXIDX_CANTUNWIND = 1;
-
-  struct Entry {
-    ul32 addr;
-    ul32 val;
-  };
-
-  if (osec->shdr.sh_size % sizeof(Entry))
-    Fatal(ctx) << "invalid .ARM.exidx section size";
-
-  Entry *ent = (Entry *)(ctx.buf + osec->shdr.sh_offset);
-  i64 num_entries = osec->shdr.sh_size / sizeof(Entry);
-
-  // Entry's addresses are relative to themselves. In order to sort
-  // records by addresses, we first translate them so that the addresses
-  // are relative to the beginning of the section.
-  auto is_relative = [](u32 val) {
-    return val != EXIDX_CANTUNWIND && !(val & 0x8000'0000);
-  };
-
-  tbb::parallel_for((i64)0, num_entries, [&](i64 i) {
-    i64 offset = sizeof(Entry) * i;
-    ent[i].addr = sign_extend(ent[i].addr, 30) + offset;
-    if (is_relative(ent[i].val))
-      ent[i].val = 0x7fff'ffff & (ent[i].val + offset);
-  });
-
-  tbb::parallel_sort(ent, ent + num_entries, [](const Entry &a, const Entry &b) {
-    return a.addr < b.addr;
-  });
-
-  // Make addresses relative to themselves.
-  tbb::parallel_for((i64)0, num_entries, [&](i64 i) {
-    i64 offset = sizeof(Entry) * i;
-    ent[i].addr = 0x7fff'ffff & (ent[i].addr - offset);
-    if (is_relative(ent[i].val))
-      ent[i].val = 0x7fff'ffff & (ent[i].val - offset);
-  });
-
-  // .ARM.exidx's sh_link should be set to the .text section index.
-  // Runtime doesn't care about it, but the binutils's strip command does.
-  if (ctx.shdr) {
-    if (Chunk<E> *text = find_section(ctx, ".text")) {
-      osec->shdr.sh_link = text->shndx;
-      ctx.shdr->copy_buf(ctx);
-    }
-  }
-}
-
-} // namespace mold::elf

elf/arch-ppc64v2.cc

@@ -1,461 +0,0 @@
-// This file implements the PowerPC ELFv2 ABI which was standardized in
-// 2014. Modern little-endian PowerPC systems are based on this ABI.
-// The ABI is often referred to as "ppc64le". This shouldn't be confused
-// with "ppc64" which refers the original, big-endian PowerPC systems.
-//
-// PPC64 is a bit tricky to support because PC-relative load/store
-// instructions are generally not available. Therefore, it's not easy
-// for position-independent code to load a value from, for example,
-// .got, as we can't do that with [PC + the offset to the .got entry].
-//
-// We can get the program counter by the following four instructions
-//
-//   mflr  r1  // save the current link register to r1
-//   bl    .+4 // branch to the next instruction as if it were a function
-//   mflr  r0  // copy the return address to r0
-//   mtlr  r1  // restore the original link register value
-//
-// , but that's too expensive to do if we do this for each load/store.
-//
-// As a workaround, most functions are compiled in such a way that r2 is
-// assumed to always contain the address of .got + 0x8000. With this, we
-// can for example load the first entry of .got with a single instruction
-// `lw r0, -0x8000(r2)`. r2 is called the TOC pointer.
-//
-// There's only one .got for each ELF module. Therefore, if a callee is in
-// the same ELF module, r2 doesn't have to be recomputed. Most function
-// calls are usually within the same ELF module, so this mechanism is
-// efficient.
-//
-// In PPC64, a function usually have two entry points, global and local.
-// The global entry point is usually 8 bytes precedes the local entry
-// point. In between is the following instructions:
-//
-//   addis r2, r12, .TOC.@ha
-//   addi  r2, r2,  .TOC.@lo + 4;
-//
-// The global entry point assumes that the address of itself is in r12,
-// and it computes its own TOC pointer from r12. It's easy to do so for
-// the callee because the offset between its .got + 0x8000 and the
-// function is known at link-time. The above code sequence then falls
-// through to the local entry point that assumes r2 is .got + 0x8000.
-//
-// So, if a callee's TOC pointer is different from the current one
-// (e.g. calling a function in another .so), we first load the callee's
-// address to r12 (e.g. from .got.plt with a r2-relative load) and branch
-// to that address. Then the callee computes its own TOC pointer using
-// r12.
-//
-// Note on section names: the PPC64 psABI uses a weird naming convention
-// which calls .got.plt .plt. We ignored that part because it's just
-// confusing. Since the runtime only cares about segments, we should be
-// able to name sections whatever we want.
-//
-// https://github.com/rui314/psabi/blob/main/ppc64v2.pdf
-
-#include "mold.h"
-
-namespace mold::elf {
-
-using E = PPC64V2;
-
-static u64 lo(u64 x)    { return x & 0xffff; }
-static u64 hi(u64 x)    { return x >> 16; }
-static u64 ha(u64 x)    { return (x + 0x8000) >> 16; }
-static u64 high(u64 x)  { return (x >> 16) & 0xffff; }
-static u64 higha(u64 x) { return ((x + 0x8000) >> 16) & 0xffff; }
-
-// .plt is used only for lazy symbol resolution on PPC64. All PLT
-// calls are made via range extension thunks even if they are within
-// reach. Thunks read addresses from .got.plt and jump there.
-// Therefore, once PLT symbols are resolved and final addresses are
-// written to .got.plt, thunks just skip .plt and directly jump to the
-// resolved addresses.
-template <>
-void write_plt_header(Context<E> &ctx, u8 *buf) {
-  static const ul32 insn[] = {
-    // Get PC
-    0x7c08'02a6, // mflr    r0
-    0x429f'0005, // bcl     20, 31, 4 // obtain PC
-    0x7d68'02a6, // mflr    r11
-    0x7c08'03a6, // mtlr    r0
-
-    // Compute the PLT entry index
-    0xe80b'002c, // ld      r0, 44(r11)
-    0x7d8b'6050, // subf    r12, r11, r12
-    0x7d60'5a14, // add     r11, r0, r11
-    0x380c'ffcc, // addi    r0, r12, -52
-    0x7800'f082, // rldicl  r0, r0, 62, 2
-
-    // Load .got.plt[0] and .got.plt[1] and branch to .got.plt[0]
-    0xe98b'0000, // ld      r12, 0(r11)
-    0x7d89'03a6, // mtctr   r12
-    0xe96b'0008, // ld      r11, 8(r11)
-    0x4e80'0420, // bctr
-
-    // .quad .got.plt - .plt - 8
-    0x0000'0000,
-    0x0000'0000,
-  };
-
-  memcpy(buf, insn, sizeof(insn));
-  *(ul64 *)(buf + 52) = ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 8;
-}
-
-template <>
-void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
-  // When the control is transferred to a PLT entry, the PLT entry's
-  // address is already set to %r12 by the caller.
-  i64 offset = ctx.plt->shdr.sh_addr - sym.get_plt_addr(ctx);
-  *(ul32 *)buf = 0x4b00'0000 | (offset & 0x00ff'ffff);        // b plt0
-}
-
-// .plt.got is not necessary on PPC64 because range extension thunks
-// directly read GOT entries and jump there.
-template <>
-void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {}
-
-template <>
-void EhFrameSection<E>::apply_reloc(Context<E> &ctx, const ElfRel<E> &rel,
-                                    u64 offset, u64 val) {
-  u8 *loc = ctx.buf + this->shdr.sh_offset + offset;
-
-  switch (rel.r_type) {
-  case R_NONE:
-    break;
-  case R_PPC64_ADDR64:
-    *(ul64 *)loc = val;
-    break;
-  case R_PPC64_REL32:
-    *(ul32 *)loc = val - this->shdr.sh_addr - offset;
-    break;
-  case R_PPC64_REL64:
-    *(ul64 *)loc = val - this->shdr.sh_addr - offset;
-    break;
-  default:
-    Fatal(ctx) << "unsupported relocation in .eh_frame: " << rel;
-  }
-}
-
-static u64 get_local_entry_offset(Context<E> &ctx, Symbol<E> &sym) {
-  i64 val = sym.esym().ppc_local_entry;
-  assert(val <= 7);
-  if (val == 0 || val == 1)
-    return 0;
-  if (val == 7)
-    Fatal(ctx) << sym << ": local entry offset 7 is reserved";
-  return 1 << val;
-}
-
-template <>
-void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-
-  ElfRel<E> *dynrel = nullptr;
-  if (ctx.reldyn)
-    dynrel = (ElfRel<E> *)(ctx.buf + ctx.reldyn->shdr.sh_offset +
-                           file.reldyn_offset + this->reldyn_offset);
-
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
-      continue;
-
-    Symbol<E> &sym = *file.symbols[rel.r_sym];
-    u8 *loc = base + rel.r_offset;
-
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
-    u64 S = sym.get_addr(ctx);
-    u64 A = rel.r_addend;
-    u64 P = get_addr() + rel.r_offset;
-    u64 G = sym.get_got_idx(ctx) * sizeof(Word<E>);
-    u64 GOT = ctx.got->shdr.sh_addr;
-    u64 TOC = ctx.extra.TOC->value;
-
-    switch (rel.r_type) {
-    case R_PPC64_ADDR64:
-      if (name() == ".toc")
-        apply_toc_rel(ctx, sym, rel, loc, S, A, P, dynrel);
-      else
-        apply_dyn_absrel(ctx, sym, rel, loc, S, A, P, dynrel);
-      break;
-    case R_PPC64_TOC16_HA:
-      *(ul16 *)loc = ha(S + A - TOC);
-      break;
-    case R_PPC64_TOC16_LO:
-      *(ul16 *)loc = lo(S + A - TOC);
-      break;
-    case R_PPC64_TOC16_DS:
-    case R_PPC64_TOC16_LO_DS:
-      *(ul16 *)loc |= (S + A - TOC) & 0xfffc;
-      break;
-    case R_PPC64_REL24: {
-      i64 val = S + A - P + get_local_entry_offset(ctx, sym);
-      if (sym.has_plt(ctx) || sign_extend(val, 25) != val)
-        val = get_thunk_addr(i) + A - P;
-
-      check(val, -(1 << 25), 1 << 25);
-      *(ul32 *)loc |= bits(val, 25, 2) << 2;
-
-      // If a callee is an external function, PLT saves %r2 to the
-      // caller's r2 save slot. We need to restore it after function
-      // return. To do so, there's usually a NOP as a placeholder
-      // after a BL. 0x6000'0000 is a NOP.
-      if (sym.has_plt(ctx) && *(ul32 *)(loc + 4) == 0x6000'0000)
-        *(ul32 *)(loc + 4) = 0xe841'0018; // ld r2, 24(r1)
-      break;
-    }
-    case R_PPC64_REL64:
-      *(ul64 *)loc = S + A - P;
-      break;
-    case R_PPC64_REL16_HA:
-      *(ul16 *)loc = ha(S + A - P);
-      break;
-    case R_PPC64_REL16_LO:
-      *(ul16 *)loc = lo(S + A - P);
-      break;
-    case R_PPC64_PLT16_HA:
-      *(ul16 *)loc = ha(G + GOT - TOC);
-      break;
-    case R_PPC64_PLT16_HI:
-      *(ul16 *)loc = hi(G + GOT - TOC);
-      break;
-    case R_PPC64_PLT16_LO:
-      *(ul16 *)loc = lo(G + GOT - TOC);
-      break;
-    case R_PPC64_PLT16_LO_DS:
-      *(ul16 *)loc |= (G + GOT - TOC) & 0xfffc;
-      break;
-    case R_PPC64_GOT_TPREL16_HA:
-      *(ul16 *)loc = ha(sym.get_gottp_addr(ctx) - TOC);
-      break;
-    case R_PPC64_GOT_TLSGD16_HA:
-      *(ul16 *)loc = ha(sym.get_tlsgd_addr(ctx) - TOC);
-      break;
-    case R_PPC64_GOT_TLSGD16_LO:
-      *(ul16 *)loc = lo(sym.get_tlsgd_addr(ctx) - TOC);
-      break;
-    case R_PPC64_GOT_TLSLD16_HA:
-      *(ul16 *)loc = ha(ctx.got->get_tlsld_addr(ctx) - TOC);
-      break;
-    case R_PPC64_GOT_TLSLD16_LO:
-      *(ul16 *)loc = lo(ctx.got->get_tlsld_addr(ctx) - TOC);
-      break;
-    case R_PPC64_DTPREL16_HA:
-      *(ul16 *)loc = ha(S + A - ctx.dtp_addr);
-      break;
-    case R_PPC64_TPREL16_HA:
-      *(ul16 *)loc = ha(S + A - ctx.tp_addr);
-      break;
-    case R_PPC64_DTPREL16_LO:
-      *(ul16 *)loc = lo(S + A - ctx.dtp_addr);
-      break;
-    case R_PPC64_TPREL16_LO:
-      *(ul16 *)loc = lo(S + A - ctx.tp_addr);
-      break;
-    case R_PPC64_GOT_TPREL16_LO_DS:
-      *(ul16 *)loc |= (sym.get_gottp_addr(ctx) - TOC) & 0xfffc;
-      break;
-    case R_PPC64_PLTSEQ:
-    case R_PPC64_PLTCALL:
-    case R_PPC64_TLS:
-    case R_PPC64_TLSGD:
-    case R_PPC64_TLSLD:
-      break;
-    default:
-      unreachable();
-    }
-  }
-}
-
-template <>
-void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
-      continue;
-
-    Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-    u8 *loc = base + rel.r_offset;
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
-    SectionFragment<E> *frag;
-    i64 frag_addend;
-    std::tie(frag, frag_addend) = get_fragment(ctx, rel);
-
-    u64 S = frag ? frag->get_addr(ctx) : sym.get_addr(ctx);
-    u64 A = frag ? frag_addend : (i64)rel.r_addend;
-
-    switch (rel.r_type) {
-    case R_PPC64_ADDR64:
-      if (std::optional<u64> val = get_tombstone(sym, frag))
-        *(ul64 *)loc = *val;
-      else
-        *(ul64 *)loc = S + A;
-      break;
-    case R_PPC64_ADDR32: {
-      i64 val = S + A;
-      check(val, 0, 1LL << 32);
-      *(ul32 *)loc = val;
-      break;
-    }
-    case R_PPC64_DTPREL64:
-      *(ul64 *)loc = S + A - ctx.dtp_addr;
-      break;
-    default:
-      Fatal(ctx) << *this << ": invalid relocation for non-allocated sections: "
-                 << rel;
-    }
-  }
-}
-
-template <>
-void InputSection<E>::scan_relocations(Context<E> &ctx) {
-  assert(shdr().sh_flags & SHF_ALLOC);
-
-  this->reldyn_offset = file.num_dynrel * sizeof(ElfRel<E>);
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-
-  // Scan relocations
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
-      continue;
-
-    Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
-    if (sym.is_ifunc())
-      sym.flags |= NEEDS_GOT | NEEDS_PLT;
-
-    switch (rel.r_type) {
-    case R_PPC64_ADDR64:
-      if (name() == ".toc")
-        scan_toc_rel(ctx, sym, rel);
-      else
-        scan_dyn_absrel(ctx, sym, rel);
-      break;
-    case R_PPC64_GOT_TPREL16_HA:
-      sym.flags |= NEEDS_GOTTP;
-      break;
-    case R_PPC64_REL24:
-      if (sym.is_imported)
-        sym.flags |= NEEDS_PLT;
-      break;
-    case R_PPC64_PLT16_HA:
-      sym.flags |= NEEDS_GOT;
-      break;
-    case R_PPC64_GOT_TLSGD16_HA:
-      sym.flags |= NEEDS_TLSGD;
-      break;
-    case R_PPC64_GOT_TLSLD16_HA:
-      ctx.needs_tlsld = true;
-      break;
-    case R_PPC64_TPREL16_HA:
-    case R_PPC64_TPREL16_LO:
-      check_tlsle(ctx, sym, rel);
-      break;
-    case R_PPC64_REL64:
-    case R_PPC64_TOC16_HA:
-    case R_PPC64_TOC16_LO:
-    case R_PPC64_TOC16_LO_DS:
-    case R_PPC64_TOC16_DS:
-    case R_PPC64_REL16_HA:
-    case R_PPC64_REL16_LO:
-    case R_PPC64_PLT16_HI:
-    case R_PPC64_PLT16_LO:
-    case R_PPC64_PLT16_LO_DS:
-    case R_PPC64_PLTSEQ:
-    case R_PPC64_PLTCALL:
-    case R_PPC64_GOT_TPREL16_LO_DS:
-    case R_PPC64_GOT_TLSGD16_LO:
-    case R_PPC64_GOT_TLSLD16_LO:
-    case R_PPC64_TLS:
-    case R_PPC64_TLSGD:
-    case R_PPC64_TLSLD:
-    case R_PPC64_DTPREL16_HA:
-    case R_PPC64_DTPREL16_LO:
-      break;
-    default:
-      Error(ctx) << *this << ": unknown relocation: " << rel;
-    }
-  }
-}
-
-template <>
-void RangeExtensionThunk<E>::copy_buf(Context<E> &ctx) {
-  u8 *buf = ctx.buf + output_section.shdr.sh_offset + offset;
-
-  // If the destination is PLT, we read an address from .got.plt or .got
-  // and jump there.
-  static const ul32 plt_thunk[] = {
-    // Save r2 to the r2 save slot reserved in the caller's stack frame
-    0xf841'0018, // std   r2, 24(r1)
-
-    // Jump to a PLT entry
-    0x3d82'0000, // addis r12, r2, foo@gotplt@toc@ha
-    0xe98c'0000, // ld    r12, foo@gotplt@toc@lo(r12)
-    0x7d89'03a6, // mtctr r12
-    0x4e80'0420, // bctr
-  };
-
-  // If the destination is a non-imported function, we directly jump
-  // to its local entry point.
-  static const ul32 local_thunk[] = {
-    // Jump to a local entry point
-    0x3d82'0000, // addis r12, r2,  foo@toc@ha
-    0x398c'0000, // addi  r12, r12, foo@toc@lo
-    0x7d89'03a6, // mtctr r12
-    0x4e80'0420, // bctr
-    0x6000'0000, // nop
-  };
-
-  static_assert(E::thunk_size == sizeof(plt_thunk));
-  static_assert(E::thunk_size == sizeof(local_thunk));
-
-  for (i64 i = 0; i < symbols.size(); i++) {
-    Symbol<E> &sym = *symbols[i];
-    ul32 *loc = (ul32 *)(buf + i * E::thunk_size);
-
-    if (sym.has_plt(ctx)) {
-      memcpy(loc, plt_thunk, sizeof(plt_thunk));
-      u64 got = sym.has_got(ctx) ? sym.get_got_addr(ctx) : sym.get_gotplt_addr(ctx);
-      i64 val = got - ctx.extra.TOC->value;
-      loc[1] |= higha(val);
-      loc[2] |= lo(val);
-    } else {
-      memcpy(loc, local_thunk, sizeof(local_thunk));
-      i64 val = sym.get_addr(ctx) + get_local_entry_offset(ctx, sym) -
-                ctx.extra.TOC->value;
-      loc[0] |= higha(val);
-      loc[1] |= lo(val);
-    }
-  }
-}
-
-} // namespace mold::elf

elf/arch-riscv.cc

@@ -1,946 +0,0 @@
-// RISC-V is a clean RISC ISA. It supports PC-relative load/store for
-// position-independent code. Its 32-bit and 64-bit ISAs are almost
-// identical. That is, you can think RV32 as a RV64 without 64-bit
-// operations. In this file, we support both RV64 and RV32.
-//
-// RISC-V is essentially little-endian, but the big-endian version is
-// available as an extension. GCC supports `-mbig-endian` to generate
-// big-endian code. Even in big-endian mode, machine instructions are
-// defined to be encoded in little-endian, though. Only the behavior of
-// load/store instructions are different between LE RISC-V and BE RISC-V.
-//
-// From the linker's point of view, the RISC-V's psABI is unique because
-// sections in input object files can be shrunk while being copied to the
-// output file. That is contrary to other psABIs in which sections are an
-// atomic unit of copying. Let me explain it in more details.
-//
-// Since RISC-V instructions are 16-bit or 32-bit long, there's no way to
-// embed a very large immediate into a branch instruction. In fact, JAL
-// (jump and link) instruction can jump to only within PC ± 1 MiB because
-// its immediate is only 21 bits long. If the destination is out of its
-// reach, we need to use two instructions instead; the first instruction
-// being AUIPC which sets upper 20 bits to a register and the second being
-// JALR with a 12-bit immediate and the register. Combined, they specify a
-// 32 bits displacement.
-//
-// Other RISC ISAs have the same limitation, and they solved the problem by
-// letting the linker create so-called "range extension thunks". It works as
-// follows: the compiler optimistically emits single jump instructions for
-// function calls. If the linker finds that a branch target is out of reach,
-// it emits a small piece of machine code near the branch instruction and
-// redirect the branch to the linker-synthesized code. The code constructs a
-// full 32-bit address in a register and jump to the destination. That
-// linker-synthesized code is called "range extension thunks" or just
-// "thunks".
-//
-// The RISC-V psABI is unique that it works the other way around. That is,
-// for RISC-V, the compiler always emits two instructions (AUIPC + JAL) for
-// function calls. If the linker finds the destination is reachable with a
-// single instruction, it replaces the two instructions with the one and
-// shrink the section size by one instruction length, instead of filling the
-// gap with a nop.
-//
-// With the presence of this relaxation, sections can no longer be
-// considered as an atomic unit. If we delete 4 bytes from the middle of a
-// section, all contents after that point needs to be shifted by 4. Symbol
-// values and relocation offsets have to be adjusted accordingly if they
-// refer past the deleted bytes.
-//
-// In mold, we use `r_deltas` to memorize how many bytes have be adjusted
-// for relocations. For symbols, we directly mutate their `value` member.
-//
-// RISC-V object files tend to have way more relocations than those for
-// other targets. This is because all branches, including ones that jump
-// within the same section, are explicitly expressed with relocations.
-// Here is why we need them: all control-flow statements such as `if` or
-// `for` are implemented using branch instructions. For other targets, the
-// compiler doesn't emit relocations for such branches because they know
-// at compile-time exactly how many bytes has to be skipped. That's not
-// true to RISC-V because the linker may delete bytes between a branch and
-// its destination. Therefore, all branches including in-section ones have
-// to be explicitly expressed with relocations.
-//
-// Note that this mechanism only shrink sections and never enlarge, as
-// the compiler always emits the longest instruction sequence. This
-// makes the linker implementation a bit simpler because we don't need
-// to worry about oscillation.
-//
-// https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-elf.adoc
-
-#include "mold.h"
-
-#include <tbb/parallel_for.h>
-#include <tbb/parallel_for_each.h>
-
-namespace mold::elf {
-
-static u32 itype(u32 val) {
-  return val << 20;
-}
-
-static u32 stype(u32 val) {
-  return bits(val, 11, 5) << 25 | bits(val, 4, 0) << 7;
-}
-
-static u32 btype(u32 val) {
-  return bit(val, 12) << 31 | bits(val, 10, 5) << 25 |
-         bits(val, 4, 1) << 8 | bit(val, 11) << 7;
-}
-
-static u32 utype(u32 val) {
-  // U-type instructions are used in combination with I-type
-  // instructions. U-type insn sets an immediate to the upper 20-bits
-  // of a register. I-type insn sign-extends a 12-bits immediate and
-  // adds it to a register value to construct a complete value. 0x800
-  // is added here to compensate for the sign-extension.
-  return (val + 0x800) & 0xffff'f000;
-}
-
-static u32 jtype(u32 val) {
-  return bit(val, 20) << 31 | bits(val, 10, 1)  << 21 |
-         bit(val, 11) << 20 | bits(val, 19, 12) << 12;
-}
-
-static u32 cbtype(u32 val) {
-  return bit(val, 8) << 12 | bit(val, 4) << 11 | bit(val, 3) << 10 |
-         bit(val, 7) << 6  | bit(val, 6) << 5  | bit(val, 2) << 4  |
-         bit(val, 1) << 3  | bit(val, 5) << 2;
-}
-
-static u32 cjtype(u32 val) {
-  return bit(val, 11) << 12 | bit(val, 4)  << 11 | bit(val, 9) << 10 |
-         bit(val, 8)  << 9  | bit(val, 10) << 8  | bit(val, 6) << 7  |
-         bit(val, 7)  << 6  | bit(val, 3)  << 5  | bit(val, 2) << 4  |
-         bit(val, 1)  << 3  | bit(val, 5)  << 2;
-}
-
-static void write_itype(u8 *loc, u32 val) {
-  *(ul32 *)loc &= 0b000000'00000'11111'111'11111'1111111;
-  *(ul32 *)loc |= itype(val);
-}
-
-static void write_stype(u8 *loc, u32 val) {
-  *(ul32 *)loc &= 0b000000'11111'11111'111'00000'1111111;
-  *(ul32 *)loc |= stype(val);
-}
-
-static void write_btype(u8 *loc, u32 val) {
-  *(ul32 *)loc &= 0b000000'11111'11111'111'00000'1111111;
-  *(ul32 *)loc |= btype(val);
-}
-
-static void write_utype(u8 *loc, u32 val) {
-  *(ul32 *)loc &= 0b000000'00000'00000'000'11111'1111111;
-  *(ul32 *)loc |= utype(val);
-}
-
-static void write_jtype(u8 *loc, u32 val) {
-  *(ul32 *)loc &= 0b000000'00000'00000'000'11111'1111111;
-  *(ul32 *)loc |= jtype(val);
-}
-
-static void write_cbtype(u8 *loc, u32 val) {
-  *(ul16 *)loc &= 0b111'000'111'00000'11;
-  *(ul16 *)loc |= cbtype(val);
-}
-
-static void write_cjtype(u8 *loc, u32 val) {
-  *(ul16 *)loc &= 0b111'00000000000'11;
-  *(ul16 *)loc |= cjtype(val);
-}
-
-// Returns the rd register of an R/I/U/J-type instruction.
-static u32 get_rd(u32 val) {
-  return bits(val, 11, 7);
-}
-
-static void set_rs1(u8 *loc, u32 rs1) {
-  assert(rs1 < 32);
-  *(ul32 *)loc &= 0b111111'11111'00000'111'11111'1111111;
-  *(ul32 *)loc |= rs1 << 15;
-}
-
-template <typename E>
-void write_plt_header(Context<E> &ctx, u8 *buf) {
-  static const ul32 insn_64[] = {
-    0x0000'0397, // auipc  t2, %pcrel_hi(.got.plt)
-    0x41c3'0333, // sub    t1, t1, t3               # .plt entry + hdr + 12
-    0x0003'be03, // ld     t3, %pcrel_lo(1b)(t2)    # _dl_runtime_resolve
-    0xfd43'0313, // addi   t1, t1, -44              # .plt entry
-    0x0003'8293, // addi   t0, t2, %pcrel_lo(1b)    # &.got.plt
-    0x0013'5313, // srli   t1, t1, 1                # .plt entry offset
-    0x0082'b283, // ld     t0, 8(t0)                # link map
-    0x000e'0067, // jr     t3
-  };
-
-  static const ul32 insn_32[] = {
-    0x0000'0397, // auipc  t2, %pcrel_hi(.got.plt)
-    0x41c3'0333, // sub    t1, t1, t3               # .plt entry + hdr + 12
-    0x0003'ae03, // lw     t3, %pcrel_lo(1b)(t2)    # _dl_runtime_resolve
-    0xfd43'0313, // addi   t1, t1, -44              # .plt entry
-    0x0003'8293, // addi   t0, t2, %pcrel_lo(1b)    # &.got.plt
-    0x0023'5313, // srli   t1, t1, 2                # .plt entry offset
-    0x0042'a283, // lw     t0, 4(t0)                # link map
-    0x000e'0067, // jr     t3
-  };
-
-  if constexpr (E::is_64)
-    memcpy(buf, insn_64, sizeof(insn_64));
-  else
-    memcpy(buf, insn_32, sizeof(insn_32));
-
-  u64 gotplt = ctx.gotplt->shdr.sh_addr;
-  u64 plt = ctx.plt->shdr.sh_addr;
-  write_utype(buf, gotplt - plt);
-  write_itype(buf + 8, gotplt - plt);
-  write_itype(buf + 16, gotplt - plt);
-}
-
-static const ul32 plt_entry_64[] = {
-  0x0000'0e17, // auipc   t3, %pcrel_hi([email protected])
-  0x000e'3e03, // ld      t3, %pcrel_lo(1b)(t3)
-  0x000e'0367, // jalr    t1, t3
-  0x0000'0013, // nop
-};
-
-static const ul32 plt_entry_32[] = {
-  0x0000'0e17, // auipc   t3, %pcrel_hi([email protected])
-  0x000e'2e03, // lw      t3, %pcrel_lo(1b)(t3)
-  0x000e'0367, // jalr    t1, t3
-  0x0000'0013, // nop
-};
-
-template <typename E>
-void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
-  if constexpr (E::is_64)
-    memcpy(buf, plt_entry_64, sizeof(plt_entry_64));
-  else
-    memcpy(buf, plt_entry_32, sizeof(plt_entry_32));
-
-  u64 gotplt = sym.get_gotplt_addr(ctx);
-  u64 plt = sym.get_plt_addr(ctx);
-  write_utype(buf, gotplt - plt);
-  write_itype(buf + 4, gotplt - plt);
-}
-
-template <typename E>
-void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
-  if constexpr (E::is_64)
-    memcpy(buf, plt_entry_64, sizeof(plt_entry_64));
-  else
-    memcpy(buf, plt_entry_32, sizeof(plt_entry_32));
-
-  u64 got = sym.get_got_addr(ctx);
-  u64 plt = sym.get_plt_addr(ctx);
-  write_utype(buf, got - plt);
-  write_itype(buf + 4, got - plt);
-}
-
-template <typename E>
-void EhFrameSection<E>::apply_reloc(Context<E> &ctx, const ElfRel<E> &rel,
-                                    u64 offset, u64 val) {
-  u8 *loc = ctx.buf + this->shdr.sh_offset + offset;
-
-  switch (rel.r_type) {
-  case R_NONE:
-    break;
-  case R_RISCV_ADD32:
-    *(U32<E> *)loc += val;
-    break;
-  case R_RISCV_SUB8:
-    *loc -= val;
-    break;
-  case R_RISCV_SUB16:
-    *(U16<E> *)loc -= val;
-    break;
-  case R_RISCV_SUB32:
-    *(U32<E> *)loc -= val;
-    break;
-  case R_RISCV_SUB6:
-    *loc = (*loc & 0b1100'0000) | ((*loc - val) & 0b0011'1111);
-    break;
-  case R_RISCV_SET6:
-    *loc = (*loc & 0b1100'0000) | (val & 0b0011'1111);
-    break;
-  case R_RISCV_SET8:
-    *loc = val;
-    break;
-  case R_RISCV_SET16:
-    *(U16<E> *)loc = val;
-    break;
-  case R_RISCV_SET32:
-    *(U32<E> *)loc = val;
-    break;
-  case R_RISCV_32_PCREL:
-    *(U32<E> *)loc = val - this->shdr.sh_addr - offset;
-    break;
-  default:
-    Fatal(ctx) << "unsupported relocation in .eh_frame: " << rel;
-  }
-}
-
-template <typename E>
-void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-
-  ElfRel<E> *dynrel = nullptr;
-  if (ctx.reldyn)
-    dynrel = (ElfRel<E> *)(ctx.buf + ctx.reldyn->shdr.sh_offset +
-                           file.reldyn_offset + this->reldyn_offset);
-
-  auto get_r_delta = [&](i64 idx) {
-    return extra.r_deltas.empty() ? 0 : extra.r_deltas[idx];
-  };
-
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE || rel.r_type == R_RISCV_RELAX)
-      continue;
-
-    Symbol<E> &sym = *file.symbols[rel.r_sym];
-    i64 r_offset = rel.r_offset - get_r_delta(i);
-    i64 removed_bytes = get_r_delta(i + 1) - get_r_delta(i);
-    u8 *loc = base + r_offset;
-
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
-    u64 S = sym.get_addr(ctx);
-    u64 A = rel.r_addend;
-    u64 P = get_addr() + r_offset;
-    u64 G = sym.get_got_idx(ctx) * sizeof(Word<E>);
-    u64 GOT = ctx.got->shdr.sh_addr;
-
-    switch (rel.r_type) {
-    case R_RISCV_32:
-      if constexpr (E::is_64)
-        *(U32<E> *)loc = S + A;
-      else
-        apply_dyn_absrel(ctx, sym, rel, loc, S, A, P, dynrel);
-      break;
-    case R_RISCV_64:
-      assert(E::is_64);
-      apply_dyn_absrel(ctx, sym, rel, loc, S, A, P, dynrel);
-      break;
-    case R_RISCV_BRANCH:
-      check(S + A - P, -(1 << 12), 1 << 12);
-      write_btype(loc, S + A - P);
-      break;
-    case R_RISCV_JAL:
-      check(S + A - P, -(1 << 20), 1 << 20);
-      write_jtype(loc, S + A - P);
-      break;
-    case R_RISCV_CALL:
-    case R_RISCV_CALL_PLT: {
-      u32 rd = get_rd(*(ul32 *)(contents.data() + rel.r_offset + 4));
-
-      if (removed_bytes == 4) {
-        // auipc + jalr -> jal
-        *(ul32 *)loc = (rd << 7) | 0b1101111;
-        write_jtype(loc, S + A - P);
-      } else if (removed_bytes == 6 && rd == 0) {
-        // auipc + jalr -> c.j
-        *(ul16 *)loc = 0b101'00000000000'01;
-        write_cjtype(loc, S + A - P);
-      } else if (removed_bytes == 6 && rd == 1) {
-        // auipc + jalr -> c.jal
-        assert(!E::is_64);
-        *(ul16 *)loc = 0b001'00000000000'01;
-        write_cjtype(loc, S + A - P);
-      } else {
-        assert(removed_bytes == 0);
-        u64 val = sym.esym().is_undef_weak() ? 0 : S + A - P;
-        check(val, -(1LL << 31), 1LL << 31);
-        write_utype(loc, val);
-        write_itype(loc + 4, val);
-      }
-      break;
-    }
-    case R_RISCV_GOT_HI20:
-      *(ul32 *)loc = G + GOT + A - P;
-      break;
-    case R_RISCV_TLS_GOT_HI20:
-      *(ul32 *)loc = sym.get_gottp_addr(ctx) + A - P;
-      break;
-    case R_RISCV_TLS_GD_HI20:
-      *(ul32 *)loc = sym.get_tlsgd_addr(ctx) + A - P;
-      break;
-    case R_RISCV_PCREL_HI20:
-      if (sym.esym().is_undef_weak()) {
-        // Calling an undefined weak symbol does not make sense.
-        // We make such call into an infinite loop. This should
-        // help debugging of a faulty program.
-        *(ul32 *)loc = 0;
-      } else {
-        *(ul32 *)loc = S + A - P;
-      }
-      break;
-    case R_RISCV_PCREL_LO12_I:
-    case R_RISCV_PCREL_LO12_S:
-      // These relocations are handled in the next loop.
-      break;
-    case R_RISCV_HI20:
-      assert(removed_bytes == 0 || removed_bytes == 4);
-      if (removed_bytes == 0) {
-        check(S + A, -(1LL << 31), 1LL << 31);
-        write_utype(loc, S + A);
-      }
-      break;
-    case R_RISCV_LO12_I:
-    case R_RISCV_LO12_S:
-      if (rel.r_type == R_RISCV_LO12_I)
-        write_itype(loc, S + A);
-      else
-        write_stype(loc, S + A);
-
-      // Rewrite `lw t1, 0(t0)` with `lw t1, 0(x0)` if the address is
-      // accessible relative to the zero register. If the upper 20 bits
-      // are all zero, the corresponding LUI might have been removed.
-      if (bits(S + A, 31, 12) == 0)
-        set_rs1(loc, 0);
-      break;
-    case R_RISCV_TPREL_HI20:
-      assert(removed_bytes == 0 || removed_bytes == 4);
-      if (removed_bytes == 0)
-        write_utype(loc, S + A - ctx.tp_addr);
-      break;
-    case R_RISCV_TPREL_ADD:
-      // This relocation just annotates an ADD instruction that can be
-      // removed when a TPREL is relaxed. No value is needed to be
-      // written.
-      assert(removed_bytes == 0 || removed_bytes == 4);
-      break;
-    case R_RISCV_TPREL_LO12_I:
-    case R_RISCV_TPREL_LO12_S: {
-      i64 val = S + A - ctx.tp_addr;
-      if (rel.r_type == R_RISCV_TPREL_LO12_I)
-        write_itype(loc, val);
-      else
-        write_stype(loc, val);
-
-      // Rewrite `lw t1, 0(t0)` with `lw t1, 0(tp)` if the address is
-      // directly accessible using tp. tp is x4.
-      if (sign_extend(val, 11) == val)
-        set_rs1(loc, 4);
-      break;
-    }
-    case R_RISCV_ADD8:
-      loc += S + A;
-      break;
-    case R_RISCV_ADD16:
-      *(U16<E> *)loc += S + A;
-      break;
-    case R_RISCV_ADD32:
-      *(U32<E> *)loc += S + A;
-      break;
-    case R_RISCV_ADD64:
-      *(U64<E> *)loc += S + A;
-      break;
-    case R_RISCV_SUB8:
-      loc -= S + A;
-      break;
-    case R_RISCV_SUB16:
-      *(U16<E> *)loc -= S + A;
-      break;
-    case R_RISCV_SUB32:
-      *(U32<E> *)loc -= S + A;
-      break;
-    case R_RISCV_SUB64:
-      *(U64<E> *)loc -= S + A;
-      break;
-    case R_RISCV_ALIGN: {
-      // A R_RISCV_ALIGN is followed by a NOP sequence. We need to remove
-      // zero or more bytes so that the instruction after R_RISCV_ALIGN is
-      // aligned to a given alignment boundary.
-      //
-      // We need to guarantee that the NOP sequence is valid after byte
-      // removal (e.g. we can't remove the first 2 bytes of a 4-byte NOP).
-      // For the sake of simplicity, we always rewrite the entire NOP sequence.
-      i64 padding_bytes = rel.r_addend - removed_bytes;
-      assert((padding_bytes & 1) == 0);
-
-      i64 i = 0;
-      for (; i <= padding_bytes - 4; i += 4)
-        *(ul32 *)(loc + i) = 0x0000'0013; // nop
-      if (i < padding_bytes)
-        *(ul16 *)(loc + i) = 0x0001;      // c.nop
-      break;
-    }
-    case R_RISCV_RVC_BRANCH:
-      check(S + A - P, -(1 << 8), 1 << 8);
-      write_cbtype(loc, S + A - P);
-      break;
-    case R_RISCV_RVC_JUMP:
-      check(S + A - P, -(1 << 11), 1 << 11);
-      write_cjtype(loc, S + A - P);
-      break;
-    case R_RISCV_SUB6:
-      *loc = (*loc & 0b1100'0000) | ((*loc - (S + A)) & 0b0011'1111);
-      break;
-    case R_RISCV_SET6:
-      *loc = (*loc & 0b1100'0000) | ((S + A) & 0b0011'1111);
-      break;
-    case R_RISCV_SET8:
-      *loc = S + A;
-      break;
-    case R_RISCV_SET16:
-      *(U16<E> *)loc = S + A;
-      break;
-    case R_RISCV_SET32:
-      *(U32<E> *)loc = S + A;
-      break;
-    case R_RISCV_32_PCREL:
-      *(U32<E> *)loc = S + A - P;
-      break;
-    default:
-      unreachable();
-    }
-  }
-
-  // Handle PC-relative LO12 relocations. In the above loop, pcrel HI20
-  // relocations overwrote instructions with full 32-bit values to allow
-  // their corresponding pcrel LO12 relocations to read their values.
-  for (i64 i = 0; i < rels.size(); i++) {
-    switch (rels[i].r_type) {
-    case R_RISCV_PCREL_LO12_I:
-    case R_RISCV_PCREL_LO12_S: {
-      Symbol<E> &sym = *file.symbols[rels[i].r_sym];
-      assert(sym.get_input_section() == this);
-
-      u8 *loc = base + rels[i].r_offset - get_r_delta(i);
-      u32 val = *(ul32 *)(base + sym.value);
-
-      if (rels[i].r_type == R_RISCV_PCREL_LO12_I)
-        write_itype(loc, val);
-      else
-        write_stype(loc, val);
-    }
-    }
-  }
-
-  // Restore the original instructions pcrel HI20 relocations overwrote.
-  for (i64 i = 0; i < rels.size(); i++) {
-    switch (rels[i].r_type) {
-    case R_RISCV_GOT_HI20:
-    case R_RISCV_PCREL_HI20:
-    case R_RISCV_TLS_GOT_HI20:
-    case R_RISCV_TLS_GD_HI20: {
-      u8 *loc = base + rels[i].r_offset - get_r_delta(i);
-      u32 val = *(ul32 *)loc;
-      memcpy(loc, contents.data() + rels[i].r_offset, 4);
-      write_utype(loc, val);
-    }
-    }
-  }
-}
-
-template <typename E>
-void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
-      continue;
-
-    Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-    u8 *loc = base + rel.r_offset;
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
-    SectionFragment<E> *frag;
-    i64 frag_addend;
-    std::tie(frag, frag_addend) = get_fragment(ctx, rel);
-
-    u64 S = frag ? frag->get_addr(ctx) : sym.get_addr(ctx);
-    u64 A = frag ? frag_addend : (i64)rel.r_addend;
-
-    switch (rel.r_type) {
-    case R_RISCV_32:
-      *(U32<E> *)loc = S + A;
-      break;
-    case R_RISCV_64:
-      if (std::optional<u64> val = get_tombstone(sym, frag))
-        *(U64<E> *)loc = *val;
-      else
-        *(U64<E> *)loc = S + A;
-      break;
-    case R_RISCV_ADD8:
-      *loc += S + A;
-      break;
-    case R_RISCV_ADD16:
-      *(U16<E> *)loc += S + A;
-      break;
-    case R_RISCV_ADD32:
-      *(U32<E> *)loc += S + A;
-      break;
-    case R_RISCV_ADD64:
-      *(U64<E> *)loc += S + A;
-      break;
-    case R_RISCV_SUB8:
-      *loc -= S + A;
-      break;
-    case R_RISCV_SUB16:
-      *(U16<E> *)loc -= S + A;
-      break;
-    case R_RISCV_SUB32:
-      *(U32<E> *)loc -= S + A;
-      break;
-    case R_RISCV_SUB64:
-      *(U64<E> *)loc -= S + A;
-      break;
-    case R_RISCV_SUB6:
-      *loc = (*loc & 0b1100'0000) | ((*loc - (S + A)) & 0b0011'1111);
-      break;
-    case R_RISCV_SET6:
-      *loc = (*loc & 0b1100'0000) | ((S + A) & 0b0011'1111);
-      break;
-    case R_RISCV_SET8:
-      *loc = S + A;
-      break;
-    case R_RISCV_SET16:
-      *(U16<E> *)loc = S + A;
-      break;
-    case R_RISCV_SET32:
-      *(U32<E> *)loc = S + A;
-      break;
-    default:
-      Fatal(ctx) << *this << ": invalid relocation for non-allocated sections: "
-                 << rel;
-      break;
-    }
-  }
-}
-
-template <typename E>
-void InputSection<E>::copy_contents_riscv(Context<E> &ctx, u8 *buf) {
-  // If a section is not relaxed, we can copy it as a one big chunk.
-  if (extra.r_deltas.empty()) {
-    uncompress_to(ctx, buf);
-    return;
-  }
-
-  // A relaxed section is copied piece-wise.
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-  i64 pos = 0;
-
-  for (i64 i = 0; i < rels.size(); i++) {
-    i64 delta = extra.r_deltas[i + 1] - extra.r_deltas[i];
-    if (delta == 0)
-      continue;
-    assert(delta > 0);
-
-    const ElfRel<E> &r = rels[i];
-    memcpy(buf, contents.data() + pos, r.r_offset - pos);
-    buf += r.r_offset - pos;
-    pos = r.r_offset + delta;
-  }
-
-  memcpy(buf, contents.data() + pos, contents.size() - pos);
-}
-
-template <typename E>
-void InputSection<E>::scan_relocations(Context<E> &ctx) {
-  assert(shdr().sh_flags & SHF_ALLOC);
-
-  this->reldyn_offset = file.num_dynrel * sizeof(ElfRel<E>);
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-
-  // Scan relocations
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
-      continue;
-
-    Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
-    if (sym.is_ifunc())
-      sym.flags |= NEEDS_GOT | NEEDS_PLT;
-
-    switch (rel.r_type) {
-    case R_RISCV_32:
-      if constexpr (E::is_64)
-        scan_absrel(ctx, sym, rel);
-      else
-        scan_dyn_absrel(ctx, sym, rel);
-      break;
-    case R_RISCV_HI20:
-      scan_absrel(ctx, sym, rel);
-      break;
-    case R_RISCV_64:
-      if constexpr (!E::is_64)
-        Fatal(ctx) << *this << ": R_RISCV_64 cannot be used on RV32";
-      scan_dyn_absrel(ctx, sym, rel);
-      break;
-    case R_RISCV_CALL:
-    case R_RISCV_CALL_PLT:
-      if (sym.is_imported)
-        sym.flags |= NEEDS_PLT;
-      break;
-    case R_RISCV_GOT_HI20:
-      sym.flags |= NEEDS_GOT;
-      break;
-    case R_RISCV_TLS_GOT_HI20:
-      sym.flags |= NEEDS_GOTTP;
-      break;
-    case R_RISCV_TLS_GD_HI20:
-      sym.flags |= NEEDS_TLSGD;
-      break;
-    case R_RISCV_32_PCREL:
-      scan_pcrel(ctx, sym, rel);
-      break;
-    case R_RISCV_TPREL_HI20:
-    case R_RISCV_TPREL_LO12_I:
-    case R_RISCV_TPREL_LO12_S:
-    case R_RISCV_TPREL_ADD:
-      check_tlsle(ctx, sym, rel);
-      break;
-    case R_RISCV_BRANCH:
-    case R_RISCV_JAL:
-    case R_RISCV_PCREL_HI20:
-    case R_RISCV_PCREL_LO12_I:
-    case R_RISCV_PCREL_LO12_S:
-    case R_RISCV_LO12_I:
-    case R_RISCV_LO12_S:
-    case R_RISCV_ADD8:
-    case R_RISCV_ADD16:
-    case R_RISCV_ADD32:
-    case R_RISCV_ADD64:
-    case R_RISCV_SUB8:
-    case R_RISCV_SUB16:
-    case R_RISCV_SUB32:
-    case R_RISCV_SUB64:
-    case R_RISCV_ALIGN:
-    case R_RISCV_RVC_BRANCH:
-    case R_RISCV_RVC_JUMP:
-    case R_RISCV_RELAX:
-    case R_RISCV_SUB6:
-    case R_RISCV_SET6:
-    case R_RISCV_SET8:
-    case R_RISCV_SET16:
-    case R_RISCV_SET32:
-      break;
-    default:
-      Error(ctx) << *this << ": unknown relocation: " << rel;
-    }
-  }
-}
-
-template <typename E>
-static bool is_resizable(Context<E> &ctx, InputSection<E> *isec) {
-  return isec && isec->is_alive && (isec->shdr().sh_flags & SHF_ALLOC) &&
-         (isec->shdr().sh_flags & SHF_EXECINSTR);
-}
-
-// Returns the distance between a relocated place and a symbol.
-template <typename E>
-static i64 compute_distance(Context<E> &ctx, Symbol<E> &sym,
-                            InputSection<E> &isec, const ElfRel<E> &rel) {
-  // We handle absolute symbols as if they were infinitely far away
-  // because `shrink_section` may increase a distance between a branch
-  // instruction and an absolute symbol. Branching to an absolute
-  // location is extremely rare in real code, though.
-  if (sym.is_absolute())
-    return INT32_MAX;
-
-  // Likewise, relocations against weak undefined symbols won't be relaxed.
-  if (sym.esym().is_undef_weak())
-    return INT32_MAX;
-
-  // Compute a distance between the relocated place and the symbol.
-  i64 S = sym.get_addr(ctx);
-  i64 A = rel.r_addend;
-  i64 P = isec.get_addr() + rel.r_offset;
-  return S + A - P;
-}
-
-// Scan relocations to shrink sections.
-template <typename E>
-static void shrink_section(Context<E> &ctx, InputSection<E> &isec, bool use_rvc) {
-  std::span<const ElfRel<E>> rels = isec.get_rels(ctx);
-  isec.extra.r_deltas.resize(rels.size() + 1);
-
-  i64 delta = 0;
-
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &r = rels[i];
-    Symbol<E> &sym = *isec.file.symbols[r.r_sym];
-    isec.extra.r_deltas[i] = delta;
-
-    // Handling R_RISCV_ALIGN is mandatory.
-    //
-    // R_RISCV_ALIGN refers NOP instructions. We need to eliminate some
-    // or all of the instructions so that the instruction that immediately
-    // follows the NOPs is aligned to a specified alignment boundary.
-    if (r.r_type == R_RISCV_ALIGN) {
-      // The total bytes of NOPs is stored to r_addend, so the next
-      // instruction is r_addend away.
-      u64 loc = isec.get_addr() + r.r_offset - delta;
-      u64 next_loc = loc + r.r_addend;
-      u64 alignment = bit_ceil(r.r_addend + 1);
-      assert(alignment <= (1 << isec.p2align));
-      delta += next_loc - align_to(loc, alignment);
-      continue;
-    }
-
-    // Handling other relocations is optional.
-    if (!ctx.arg.relax || i == rels.size() - 1 ||
-        rels[i + 1].r_type != R_RISCV_RELAX)
-      continue;
-
-    // Linker-synthesized symbols haven't been assigned their final
-    // values when we are shrinking sections because actual values can
-    // be computed only after we fix the file layout. Therefore, we
-    // assume that relocations against such symbols are always
-    // non-relaxable.
-    if (sym.file == ctx.internal_obj)
-      continue;
-
-    switch (r.r_type) {
-    case R_RISCV_CALL:
-    case R_RISCV_CALL_PLT: {
-      // These relocations refer an AUIPC + JALR instruction pair to
-      // allow to jump to anywhere in PC ± 2 GiB. If the jump target is
-      // close enough to PC, we can use C.J, C.JAL or JAL instead.
-      i64 dist = compute_distance(ctx, sym, isec, r);
-      if (dist & 1)
-        break;
-
-      std::string_view contents = isec.contents;
-      i64 rd = get_rd(*(ul32 *)(contents.data() + r.r_offset + 4));
-
-      if (rd == 0 && sign_extend(dist, 11) == dist && use_rvc) {
-        // If rd is x0 and the jump target is within ±2 KiB, we can use
-        // C.J, saving 6 bytes.
-        delta += 6;
-      } else if (rd == 1 && sign_extend(dist, 11) == dist && use_rvc && !E::is_64) {
-        // If rd is x1 and the jump target is within ±2 KiB, we can use
-        // C.JAL. This is RV32 only because C.JAL is RV32-only instruction.
-        delta += 6;
-      } else if (sign_extend(dist, 20) == dist) {
-        // If the jump target is within ±1 MiB, we can use JAL.
-        delta += 4;
-      }
-      break;
-    }
-    case R_RISCV_HI20:
-      // If the upper 20 bits are all zero, we can remove LUI.
-      // The corresponding instructions referred by LO12_I/LO12_S
-      // relocations will use the zero register instead.
-      if (bits(sym.get_addr(ctx), 31, 12) == 0)
-        delta += 4;
-      break;
-    case R_RISCV_TPREL_HI20:
-    case R_RISCV_TPREL_ADD: {
-      // These relocations are used to add a high 20-bit value to the
-      // thread pointer. The following two instructions materializes
-      // TP + HI20(foo) in %r5, for example.
-      //
-      //  lui  a5,%tprel_hi(foo)         # R_RISCV_TPREL_HI20 (symbol)
-      //  add  a5,a5,tp,%tprel_add(foo)  # R_RISCV_TPREL_ADD (symbol)
-      //
-      // Then thread-local variable `foo` is accessed with a low 12-bit
-      // offset like this:
-      //
-      //  sw   t0,%tprel_lo(foo)(a5)     # R_RISCV_TPREL_LO12_S (symbol)
-      //
-      // However, if the variable is at TP ±2 KiB, TP + HI20(foo) is the
-      // same as TP, so we can instead access the thread-local variable
-      // directly using TP like this:
-      //
-      //  sw   t0,%tprel_lo(foo)(tp)
-      //
-      // Here, we remove `lui` and `add` if the offset is within ±2 KiB.
-      i64 val = sym.get_addr(ctx) + r.r_addend - ctx.tp_addr;
-      if (sign_extend(val, 11) == val)
-        delta += 4;
-      break;
-    }
-    }
-  }
-
-  isec.extra.r_deltas[rels.size()] = delta;
-  isec.sh_size -= delta;
-}
-
-// Shrink sections by interpreting relocations.
-//
-// This operation seems to be optional, because by default longest
-// instructions are being used. However, calling this function is actually
-// mandatory because of R_RISCV_ALIGN. R_RISCV_ALIGN is a directive to the
-// linker to align the location referred to by the relocation to a
-// specified byte boundary. We at least have to interpret them to satisfy
-// the alignment constraints.
-template <typename E>
-i64 riscv_resize_sections(Context<E> &ctx) {
-  Timer t(ctx, "riscv_resize_sections");
-
-  // True if we can use the 2-byte instructions. This is usually true on
-  // Unix because RV64GC is generally considered the baseline hardware.
-  bool use_rvc = get_eflags(ctx) & EF_RISCV_RVC;
-
-  // Find all the relocations that can be relaxed.
-  // This step should only shrink sections.
-  tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
-    for (std::unique_ptr<InputSection<E>> &isec : file->sections)
-      if (is_resizable(ctx, isec.get()))
-        shrink_section(ctx, *isec, use_rvc);
-  });
-
-  // Fix symbol values.
-  tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
-    for (Symbol<E> *sym : file->symbols) {
-      if (sym->file != file)
-        continue;
-
-      InputSection<E> *isec = sym->get_input_section();
-      if (!isec || isec->extra.r_deltas.empty())
-        continue;
-
-      std::span<const ElfRel<E>> rels = isec->get_rels(ctx);
-      auto it = std::lower_bound(rels.begin(), rels.end(), sym->value,
-                                 [&](const ElfRel<E> &r, u64 val) {
-        return r.r_offset < val;
-      });
-
-      sym->value -= isec->extra.r_deltas[it - rels.begin()];
-    }
-  });
-
-  // Re-compute section offset again to finalize them.
-  compute_section_sizes(ctx);
-  return set_osec_offsets(ctx);
-}
-
-#define INSTANTIATE(E)                                                       \
-  template void write_plt_header(Context<E> &, u8 *);                        \
-  template void write_plt_entry(Context<E> &, u8 *, Symbol<E> &);            \
-  template void write_pltgot_entry(Context<E> &, u8 *, Symbol<E> &);         \
-  template void                                                              \
-  EhFrameSection<E>::apply_reloc(Context<E> &, const ElfRel<E> &, u64, u64); \
-  template void InputSection<E>::apply_reloc_alloc(Context<E> &, u8 *);      \
-  template void InputSection<E>::apply_reloc_nonalloc(Context<E> &, u8 *);   \
-  template void InputSection<E>::copy_contents_riscv(Context<E> &, u8 *);    \
-  template void InputSection<E>::scan_relocations(Context<E> &);             \
-  template i64 riscv_resize_sections(Context<E> &);
-
-INSTANTIATE(RV64LE);
-INSTANTIATE(RV64BE);
-INSTANTIATE(RV32LE);
-INSTANTIATE(RV32BE);
-
-} // namespace mold::elf

elf/arch-x86-64.cc

@@ -1,786 +0,0 @@
-// Supporting x86-64 is straightforward. Unlike its predecessor, i386,
-// x86-64 supports PC-relative addressing for position-independent code.
-// Being CISC, its instructions are variable in size. Branch instructions
-// take 4 bytes offsets, so we don't need range extension thunks.
-//
-// The psABI specifies %r11 as neither caller- nor callee-saved. It's
-// intentionally left out so that we can use it as a scratch register in
-// PLT.
-//
-// Thread Pointer (TP) is stored not to a general-purpose register but to
-// FS segment register. Segment register is a 64-bits register which can
-// be used as a base address for memory access. Each thread has a unique
-// FS value, and they access their thread-local variables relative to FS
-// as %fs:offset_from_tp.
-//
-// The value of a segment register itself is not generally readable from
-// the user space. As a workaround, libc initializes %fs:0 (the first word
-// referenced by FS) to the value of %fs itself. So we can obtain TP just
-// by `mov %fs:0, %rax` if we need it.
-//
-// For historical reasons, TP points past the end of the TLS block on x86.
-// This is contrary to other psABIs which usually use the beginning of the
-// TLS block as TP (with some addend). As a result, offsets from TP to
-// thread-local variables (TLVs) in the main executable are all negative.
-//
-// https://github.com/rui314/psabi/blob/main/x86-64.pdf
-// https://github.com/rui314/psabi/blob/main/i386.pdf
-
-#include "mold.h"
-
-namespace mold::elf {
-
-using E = X86_64;
-
-// This is a security-enhanced version of the regular PLT. The PLT
-// header and each PLT entry starts with endbr64 for the Intel's
-// control-flow enforcement security mechanism.
-//
-// Note that our IBT-enabled PLT instruction sequence is different
-// from the one used in GNU ld. GNU's IBTPLT implementation uses two
-// separate sections (.plt and .plt.sec) in which one PLT entry takes
-// 32 bytes in total. Our IBTPLT consists of just .plt and each entry
-// is 16 bytes long.
-//
-// Our PLT entry clobbers %r11, but that's fine because the resolver
-// function (_dl_runtime_resolve) clobbers %r11 anyway.
-template <>
-void write_plt_header(Context<E> &ctx, u8 *buf) {
-  static const u8 insn[] = {
-    0xf3, 0x0f, 0x1e, 0xfa, // endbr64
-    0x41, 0x53,             // push %r11
-    0xff, 0x35, 0, 0, 0, 0, // push GOTPLT+8(%rip)
-    0xff, 0x25, 0, 0, 0, 0, // jmp *GOTPLT+16(%rip)
-    0xcc, 0xcc, 0xcc, 0xcc, // (padding)
-    0xcc, 0xcc, 0xcc, 0xcc, // (padding)
-    0xcc, 0xcc, 0xcc, 0xcc, // (padding)
-    0xcc, 0xcc,             // (padding)
-  };
-
-  memcpy(buf, insn, sizeof(insn));
-  *(ul32 *)(buf + 8) = ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 4;
-  *(ul32 *)(buf + 14) = ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 2;
-}
-
-template <>
-void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
-  static const u8 insn[] = {
-    0xf3, 0x0f, 0x1e, 0xfa, // endbr64
-    0x41, 0xbb, 0, 0, 0, 0, // mov $index_in_relplt, %r11d
-    0xff, 0x25, 0, 0, 0, 0, // jmp *foo@GOTPLT
-  };
-
-  memcpy(buf, insn, sizeof(insn));
-  *(ul32 *)(buf + 6) = sym.get_plt_idx(ctx);
-  *(ul32 *)(buf + 12) = sym.get_gotplt_addr(ctx) - sym.get_plt_addr(ctx) - 16;
-}
-
-template <>
-void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
-  static const u8 insn[] = {
-    0xf3, 0x0f, 0x1e, 0xfa, // endbr64
-    0xff, 0x25, 0, 0, 0, 0, // jmp *foo@GOT
-    0xcc, 0xcc, 0xcc, 0xcc, // (padding)
-    0xcc, 0xcc,             // (padding)
-  };
-
-  memcpy(buf, insn, sizeof(insn));
-  *(ul32 *)(buf + 6) = sym.get_got_addr(ctx) - sym.get_plt_addr(ctx) - 10;
-}
-
-template <>
-void EhFrameSection<E>::apply_reloc(Context<E> &ctx, const ElfRel<E> &rel,
-                                    u64 offset, u64 val) {
-  u8 *loc = ctx.buf + this->shdr.sh_offset + offset;
-
-  switch (rel.r_type) {
-  case R_NONE:
-    break;
-  case R_X86_64_32:
-    *(ul32 *)loc = val;
-    break;
-  case R_X86_64_64:
-    *(ul64 *)loc = val;
-    break;
-  case R_X86_64_PC32:
-    *(ul32 *)loc = val - this->shdr.sh_addr - offset;
-    break;
-  case R_X86_64_PC64:
-    *(ul64 *)loc = val - this->shdr.sh_addr - offset;
-    break;
-  default:
-    Fatal(ctx) << "unsupported relocation in .eh_frame: " << rel;
-  }
-}
-
-static u32 relax_gotpcrelx(u8 *loc) {
-  switch ((loc[0] << 8) | loc[1]) {
-  case 0xff15: return 0x90e8; // call *0(%rip) -> call 0
-  case 0xff25: return 0x90e9; // jmp  *0(%rip) -> jmp  0
-  }
-  return 0;
-}
-
-static u32 relax_rex_gotpcrelx(u8 *loc) {
-  switch ((loc[0] << 16) | (loc[1] << 8) | loc[2]) {
-  case 0x488b05: return 0x488d05; // mov 0(%rip), %rax -> lea 0(%rip), %rax
-  case 0x488b0d: return 0x488d0d; // mov 0(%rip), %rcx -> lea 0(%rip), %rcx
-  case 0x488b15: return 0x488d15; // mov 0(%rip), %rdx -> lea 0(%rip), %rdx
-  case 0x488b1d: return 0x488d1d; // mov 0(%rip), %rbx -> lea 0(%rip), %rbx
-  case 0x488b25: return 0x488d25; // mov 0(%rip), %rsp -> lea 0(%rip), %rsp
-  case 0x488b2d: return 0x488d2d; // mov 0(%rip), %rbp -> lea 0(%rip), %rbp
-  case 0x488b35: return 0x488d35; // mov 0(%rip), %rsi -> lea 0(%rip), %rsi
-  case 0x488b3d: return 0x488d3d; // mov 0(%rip), %rdi -> lea 0(%rip), %rdi
-  case 0x4c8b05: return 0x4c8d05; // mov 0(%rip), %r8  -> lea 0(%rip), %r8
-  case 0x4c8b0d: return 0x4c8d0d; // mov 0(%rip), %r9  -> lea 0(%rip), %r9
-  case 0x4c8b15: return 0x4c8d15; // mov 0(%rip), %r10 -> lea 0(%rip), %r10
-  case 0x4c8b1d: return 0x4c8d1d; // mov 0(%rip), %r11 -> lea 0(%rip), %r11
-  case 0x4c8b25: return 0x4c8d25; // mov 0(%rip), %r12 -> lea 0(%rip), %r12
-  case 0x4c8b2d: return 0x4c8d2d; // mov 0(%rip), %r13 -> lea 0(%rip), %r13
-  case 0x4c8b35: return 0x4c8d35; // mov 0(%rip), %r14 -> lea 0(%rip), %r14
-  case 0x4c8b3d: return 0x4c8d3d; // mov 0(%rip), %r15 -> lea 0(%rip), %r15
-  }
-  return 0;
-}
-
-static u32 relax_gottpoff(u8 *loc) {
-  switch ((loc[0] << 16) | (loc[1] << 8) | loc[2]) {
-  case 0x488b05: return 0x48c7c0; // mov 0(%rip), %rax -> mov $0, %rax
-  case 0x488b0d: return 0x48c7c1; // mov 0(%rip), %rcx -> mov $0, %rcx
-  case 0x488b15: return 0x48c7c2; // mov 0(%rip), %rdx -> mov $0, %rdx
-  case 0x488b1d: return 0x48c7c3; // mov 0(%rip), %rbx -> mov $0, %rbx
-  case 0x488b25: return 0x48c7c4; // mov 0(%rip), %rsp -> mov $0, %rsp
-  case 0x488b2d: return 0x48c7c5; // mov 0(%rip), %rbp -> mov $0, %rbp
-  case 0x488b35: return 0x48c7c6; // mov 0(%rip), %rsi -> mov $0, %rsi
-  case 0x488b3d: return 0x48c7c7; // mov 0(%rip), %rdi -> mov $0, %rdi
-  case 0x4c8b05: return 0x49c7c0; // mov 0(%rip), %r8  -> mov $0, %r8
-  case 0x4c8b0d: return 0x49c7c1; // mov 0(%rip), %r9  -> mov $0, %r9
-  case 0x4c8b15: return 0x49c7c2; // mov 0(%rip), %r10 -> mov $0, %r10
-  case 0x4c8b1d: return 0x49c7c3; // mov 0(%rip), %r11 -> mov $0, %r11
-  case 0x4c8b25: return 0x49c7c4; // mov 0(%rip), %r12 -> mov $0, %r12
-  case 0x4c8b2d: return 0x49c7c5; // mov 0(%rip), %r13 -> mov $0, %r13
-  case 0x4c8b35: return 0x49c7c6; // mov 0(%rip), %r14 -> mov $0, %r14
-  case 0x4c8b3d: return 0x49c7c7; // mov 0(%rip), %r15 -> mov $0, %r15
-  }
-  return 0;
-}
-
-static u32 relax_gotpc32_tlsdesc(u8 *loc) {
-  switch ((loc[0] << 16) | (loc[1] << 8) | loc[2]) {
-  case 0x488d05: return 0x48c7c0; // lea 0(%rip), %rax -> mov $0, %rax
-  case 0x488d0d: return 0x48c7c1; // lea 0(%rip), %rcx -> mov $0, %rcx
-  case 0x488d15: return 0x48c7c2; // lea 0(%rip), %rdx -> mov $0, %rdx
-  case 0x488d1d: return 0x48c7c3; // lea 0(%rip), %rbx -> mov $0, %rbx
-  case 0x488d25: return 0x48c7c4; // lea 0(%rip), %rsp -> mov $0, %rsp
-  case 0x488d2d: return 0x48c7c5; // lea 0(%rip), %rbp -> mov $0, %rbp
-  case 0x488d35: return 0x48c7c6; // lea 0(%rip), %rsi -> mov $0, %rsi
-  case 0x488d3d: return 0x48c7c7; // lea 0(%rip), %rdi -> mov $0, %rdi
-  case 0x4c8d05: return 0x49c7c0; // lea 0(%rip), %r8  -> mov $0, %r8
-  case 0x4c8d0d: return 0x49c7c1; // lea 0(%rip), %r9  -> mov $0, %r9
-  case 0x4c8d15: return 0x49c7c2; // lea 0(%rip), %r10 -> mov $0, %r10
-  case 0x4c8d1d: return 0x49c7c3; // lea 0(%rip), %r11 -> mov $0, %r11
-  case 0x4c8d25: return 0x49c7c4; // lea 0(%rip), %r12 -> mov $0, %r12
-  case 0x4c8d2d: return 0x49c7c5; // lea 0(%rip), %r13 -> mov $0, %r13
-  case 0x4c8d35: return 0x49c7c6; // lea 0(%rip), %r14 -> mov $0, %r14
-  case 0x4c8d3d: return 0x49c7c7; // lea 0(%rip), %r15 -> mov $0, %r15
-  }
-  return 0;
-}
-
-// Rewrite a function call to __tls_get_addr to a cheaper instruction
-// sequence. We can do this when we know the thread-local variable's TP-
-// relative address at link-time.
-static void relax_gd_to_le(u8 *loc, ElfRel<E> rel, u64 val) {
-  switch (rel.r_type) {
-  case R_X86_64_PLT32:
-  case R_X86_64_PC32:
-  case R_X86_64_GOTPCREL:
-  case R_X86_64_GOTPCRELX: {
-    // The original instructions are the following:
-    //
-    //  66 48 8d 3d 00 00 00 00    lea  foo@tlsgd(%rip), %rdi
-    //  66 66 48 e8 00 00 00 00    call __tls_get_addr
-    //
-    // or
-    //
-    //  66 48 8d 3d 00 00 00 00    lea foo@tlsgd(%rip), %rdi
-    //  66 48 ff 15 00 00 00 00    call *__tls_get_addr@GOT(%rip)
-    static const u8 insn[] = {
-      0x64, 0x48, 0x8b, 0x04, 0x25, 0, 0, 0, 0, // mov %fs:0, %rax
-      0x48, 0x81, 0xc0, 0, 0, 0, 0,             // add $tp_offset, %rax
-    };
-    memcpy(loc - 4, insn, sizeof(insn));
-    *(ul32 *)(loc + 8) = val;
-    break;
-  }
-  case R_X86_64_PLTOFF64: {
-    // The original instructions are the following:
-    //
-    //  48 8d 3d 00 00 00 00           lea    foo@tlsgd(%rip), %rdi
-    //  48 b8 00 00 00 00 00 00 00 00  movabs __tls_get_addr, %rax
-    //  48 01 d8                       add    %rbx, %rax
-    //  ff d0                          call   *%rax
-    static const u8 insn[] = {
-      0x64, 0x48, 0x8b, 0x04, 0x25, 0, 0, 0, 0, // mov %fs:0, %rax
-      0x48, 0x81, 0xc0, 0, 0, 0, 0,             // add $tp_offset, %rax
-      0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00,       // nop
-    };
-    memcpy(loc - 3, insn, sizeof(insn));
-    *(ul32 *)(loc + 9) = val;
-    break;
-  }
-  default:
-    unreachable();
-  }
-}
-
-static void relax_gd_to_ie(u8 *loc, ElfRel<E> rel, u64 val) {
-  switch (rel.r_type) {
-  case R_X86_64_PLT32:
-  case R_X86_64_PC32:
-  case R_X86_64_GOTPCREL:
-  case R_X86_64_GOTPCRELX: {
-    static const u8 insn[] = {
-      0x64, 0x48, 0x8b, 0x04, 0x25, 0, 0, 0, 0, // mov %fs:0, %rax
-      0x48, 0x03, 0x05, 0, 0, 0, 0,             // add foo@gottpoff(%rip), %rax
-    };
-    memcpy(loc - 4, insn, sizeof(insn));
-    *(ul32 *)(loc + 8) = val - 12;
-    break;
-  }
-  case R_X86_64_PLTOFF64: {
-    static const u8 insn[] = {
-      0x64, 0x48, 0x8b, 0x04, 0x25, 0, 0, 0, 0, // mov %fs:0, %rax
-      0x48, 0x03, 0x05, 0, 0, 0, 0,             // add foo@gottpoff(%rip), %rax
-      0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00,       // nop
-    };
-    memcpy(loc - 3, insn, sizeof(insn));
-    *(ul32 *)(loc + 9) = val - 13;
-    break;
-  }
-  default:
-    unreachable();
-  }
-}
-
-// Rewrite a function call to __tls_get_addr to a cheaper instruction
-// sequence. The difference from relax_gd_to_le is that we are
-// materializing a Dynamic Thread Pointer for the current ELF module
-// instead of an address for a particular thread-local variable.
-static void relax_ld_to_le(u8 *loc, ElfRel<E> rel, u64 val) {
-  switch (rel.r_type) {
-  case R_X86_64_PLT32:
-  case R_X86_64_PC32: {
-    // The original instructions are the following:
-    //
-    //  48 8d 3d 00 00 00 00    lea    foo@tlsld(%rip), %rdi
-    //  e8 00 00 00 00          call   __tls_get_addr
-    static const u8 insn[] = {
-      0x31, 0xc0,                   // xor %eax, %eax
-      0x64, 0x48, 0x8b, 0x00,       // mov %fs:(%rax), %rax
-      0x48, 0x2d, 0, 0, 0, 0,       // sub $tls_size, %rax
-    };
-    memcpy(loc - 3, insn, sizeof(insn));
-    *(ul32 *)(loc + 5) = val;
-    break;
-  }
-  case R_X86_64_GOTPCREL:
-  case R_X86_64_GOTPCRELX: {
-    // The original instructions are the following:
-    //
-    //  48 8d 3d 00 00 00 00    lea    foo@tlsld(%rip), %rdi
-    //  ff 15 00 00 00 00       call   *__tls_get_addr@GOT(%rip)
-    static const u8 insn[] = {
-      0x31, 0xc0,                   // xor %eax, %eax
-      0x64, 0x48, 0x8b, 0x00,       // mov %fs:(%rax), %rax
-      0x48, 0x2d, 0, 0, 0, 0,       // sub $tls_size, %rax
-      0x90,                         // nop
-    };
-    memcpy(loc - 3, insn, sizeof(insn));
-    *(ul32 *)(loc + 5) = val;
-    break;
-  }
-  case R_X86_64_PLTOFF64: {
-    // The original instructions are the following:
-    //
-    //  48 8d 3d 00 00 00 00           lea    foo@tlsld(%rip), %rdi
-    //  48 b8 00 00 00 00 00 00 00 00  movabs __tls_get_addr@GOTOFF, %rax
-    //  48 01 d8                       add    %rbx, %rax
-    //  ff d0                          call   *%rax
-    static const u8 insn[] = {
-      0x31, 0xc0,                   // xor %eax, %eax
-      0x64, 0x48, 0x8b, 0x00,       // mov %fs:(%rax), %rax
-      0x48, 0x2d, 0, 0, 0, 0,       // sub $tls_size, %rax
-      0x0f, 0x1f, 0x44, 0x00, 0x00, // nop
-      0x0f, 0x1f, 0x44, 0x00, 0x00, // nop
-    };
-    memcpy(loc - 3, insn, sizeof(insn));
-    *(ul32 *)(loc + 5) = val;
-    break;
-  }
-  default:
-    unreachable();
-  }
-}
-
-// Apply relocations to SHF_ALLOC sections (i.e. sections that are
-// mapped to memory at runtime) based on the result of
-// scan_relocations().
-template <>
-void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-
-  ElfRel<E> *dynrel = nullptr;
-  if (ctx.reldyn)
-    dynrel = (ElfRel<E> *)(ctx.buf + ctx.reldyn->shdr.sh_offset +
-                           file.reldyn_offset + this->reldyn_offset);
-
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
-      continue;
-
-    Symbol<E> &sym = *file.symbols[rel.r_sym];
-    u8 *loc = base + rel.r_offset;
-
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
-    auto write32 = [&](u64 val) {
-      check(val, 0, 1LL << 32);
-      *(ul32 *)loc = val;
-    };
-
-    auto write32s = [&](u64 val) {
-      check(val, -(1LL << 31), 1LL << 31);
-      *(ul32 *)loc = val;
-    };
-
-    u64 S = sym.get_addr(ctx);
-    u64 A = rel.r_addend;
-    u64 P = get_addr() + rel.r_offset;
-    u64 G = sym.get_got_addr(ctx) - ctx.gotplt->shdr.sh_addr;
-    u64 GOTPLT = ctx.gotplt->shdr.sh_addr;
-
-    switch (rel.r_type) {
-    case R_X86_64_8:
-      check(S + A, 0, 1 << 8);
-      *loc = S + A;
-      break;
-    case R_X86_64_16:
-      check(S + A, 0, 1 << 16);
-      *(ul16 *)loc = S + A;
-      break;
-    case R_X86_64_32:
-      write32(S + A);
-      break;
-    case R_X86_64_32S:
-      write32s(S + A);
-      break;
-    case R_X86_64_64:
-      apply_dyn_absrel(ctx, sym, rel, loc, S, A, P, dynrel);
-      break;
-    case R_X86_64_PC8:
-      check(S + A - P, -(1 << 7), 1 << 7);
-      *loc = S + A - P;
-      break;
-    case R_X86_64_PC16:
-      check(S + A - P, -(1 << 15), 1 << 15);
-      *(ul16 *)loc = S + A - P;
-      break;
-    case R_X86_64_PC32:
-    case R_X86_64_PLT32:
-      write32s(S + A - P);
-      break;
-    case R_X86_64_PC64:
-      *(ul64 *)loc = S + A - P;
-      break;
-    case R_X86_64_GOT32:
-      write32s(G + A);
-      break;
-    case R_X86_64_GOT64:
-      *(ul64 *)loc = G + A;
-      break;
-    case R_X86_64_GOTOFF64:
-    case R_X86_64_PLTOFF64:
-      *(ul64 *)loc = S + A - GOTPLT;
-      break;
-    case R_X86_64_GOTPC32:
-      write32s(GOTPLT + A - P);
-      break;
-    case R_X86_64_GOTPC64:
-      *(ul64 *)loc = GOTPLT + A - P;
-      break;
-    case R_X86_64_GOTPCREL:
-      write32s(G + GOTPLT + A - P);
-      break;
-    case R_X86_64_GOTPCREL64:
-      *(ul64 *)loc = G + GOTPLT + A - P;
-      break;
-    case R_X86_64_GOTPCRELX:
-      if (sym.has_got(ctx)) {
-        write32s(G + GOTPLT + A - P);
-      } else {
-        u32 insn = relax_gotpcrelx(loc - 2);
-        loc[-2] = insn >> 8;
-        loc[-1] = insn;
-        write32s(S + A - P);
-      }
-      break;
-    case R_X86_64_REX_GOTPCRELX:
-      if (sym.has_got(ctx)) {
-        write32s(G + GOTPLT + A - P);
-      } else {
-        u32 insn = relax_rex_gotpcrelx(loc - 3);
-        loc[-3] = insn >> 16;
-        loc[-2] = insn >> 8;
-        loc[-1] = insn;
-        write32s(S + A - P);
-      }
-      break;
-    case R_X86_64_TLSGD:
-      if (sym.has_tlsgd(ctx)) {
-        write32s(sym.get_tlsgd_addr(ctx) + A - P);
-      } else if (sym.has_gottp(ctx)) {
-        relax_gd_to_ie(loc, rels[i + 1], sym.get_gottp_addr(ctx) - P);
-        i++;
-      } else {
-        relax_gd_to_le(loc, rels[i + 1], S - ctx.tp_addr);
-        i++;
-      }
-      break;
-    case R_X86_64_TLSLD:
-      if (ctx.got->has_tlsld(ctx)) {
-        write32s(ctx.got->get_tlsld_addr(ctx) + A - P);
-      } else {
-        relax_ld_to_le(loc, rels[i + 1], ctx.tp_addr - ctx.tls_begin);
-        i++;
-      }
-      break;
-    case R_X86_64_DTPOFF32:
-      write32s(S + A - ctx.dtp_addr);
-      break;
-    case R_X86_64_DTPOFF64:
-      *(ul64 *)loc = S + A - ctx.dtp_addr;
-      break;
-    case R_X86_64_TPOFF32:
-      write32s(S + A - ctx.tp_addr);
-      break;
-    case R_X86_64_TPOFF64:
-      *(ul64 *)loc = S + A - ctx.tp_addr;
-      break;
-    case R_X86_64_GOTTPOFF:
-      if (sym.has_gottp(ctx)) {
-        write32s(sym.get_gottp_addr(ctx) + A - P);
-      } else {
-        u32 insn = relax_gottpoff(loc - 3);
-        loc[-3] = insn >> 16;
-        loc[-2] = insn >> 8;
-        loc[-1] = insn;
-        write32s(S - ctx.tp_addr);
-        assert(A == -4);
-      }
-      break;
-    case R_X86_64_GOTPC32_TLSDESC:
-      if (sym.has_tlsdesc(ctx)) {
-        write32s(sym.get_tlsdesc_addr(ctx) + A - P);
-      } else {
-        u32 insn = relax_gotpc32_tlsdesc(loc - 3);
-        loc[-3] = insn >> 16;
-        loc[-2] = insn >> 8;
-        loc[-1] = insn;
-        write32s(S - ctx.tp_addr);
-        assert(A == -4);
-      }
-      break;
-    case R_X86_64_SIZE32:
-      write32(sym.esym().st_size + A);
-      break;
-    case R_X86_64_SIZE64:
-      *(ul64 *)loc = sym.esym().st_size + A;
-      break;
-    case R_X86_64_TLSDESC_CALL:
-      if (!sym.has_tlsdesc(ctx)) {
-        // call *(%rax) -> nop
-        loc[0] = 0x66;
-        loc[1] = 0x90;
-      }
-      break;
-    default:
-      unreachable();
-    }
-  }
-}
-
-// This function is responsible for applying relocations against
-// non-SHF_ALLOC sections (i.e. sections that are not mapped to memory
-// at runtime).
-//
-// Relocations against non-SHF_ALLOC sections are much easier to
-// handle than that against SHF_ALLOC sections. It is because, since
-// they are not mapped to memory, they don't contain any variable or
-// function and never need PLT or GOT. Non-SHF_ALLOC sections are
-// mostly debug info sections.
-//
-// Relocations against non-SHF_ALLOC sections are not scanned by
-// scan_relocations.
-template <>
-void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
-      continue;
-
-    Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-    u8 *loc = base + rel.r_offset;
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
-    auto write32 = [&](u64 val) {
-      check(val, 0, 1LL << 32);
-      *(ul32 *)loc = val;
-    };
-
-    auto write32s = [&](u64 val) {
-      check(val, -(1LL << 31), 1LL << 31);
-      *(ul32 *)loc = val;
-    };
-
-    SectionFragment<E> *frag;
-    i64 frag_addend;
-    std::tie(frag, frag_addend) = get_fragment(ctx, rel);
-
-    u64 S = frag ? frag->get_addr(ctx) : sym.get_addr(ctx);
-    u64 A = frag ? frag_addend : (i64)rel.r_addend;
-
-    switch (rel.r_type) {
-    case R_X86_64_8:
-      check(S + A, 0, 1 << 8);
-      *loc = S + A;
-      break;
-    case R_X86_64_16:
-      check(S + A, 0, 1 << 16);
-      *(ul16 *)loc = S + A;
-      break;
-    case R_X86_64_32:
-      write32(S + A);
-      break;
-    case R_X86_64_32S:
-      write32s(S + A);
-      break;
-    case R_X86_64_64:
-      if (std::optional<u64> val = get_tombstone(sym, frag))
-        *(ul64 *)loc = *val;
-      else
-        *(ul64 *)loc = S + A;
-      break;
-    case R_X86_64_DTPOFF32:
-      if (std::optional<u64> val = get_tombstone(sym, frag))
-        *(ul32 *)loc = *val;
-      else
-        write32s(S + A - ctx.dtp_addr);
-      break;
-    case R_X86_64_DTPOFF64:
-      if (std::optional<u64> val = get_tombstone(sym, frag))
-        *(ul64 *)loc = *val;
-      else
-        *(ul64 *)loc = S + A - ctx.dtp_addr;
-      break;
-    case R_X86_64_SIZE32:
-      write32(sym.esym().st_size + A);
-      break;
-    case R_X86_64_SIZE64:
-      *(ul64 *)loc = sym.esym().st_size + A;
-      break;
-    default:
-      Fatal(ctx) << *this << ": invalid relocation for non-allocated sections: "
-                 << rel;
-      break;
-    }
-  }
-}
-
-// Linker has to create data structures in an output file to apply
-// some type of relocations. For example, if a relocation refers a GOT
-// or a PLT entry of a symbol, linker has to create an entry in .got
-// or in .plt for that symbol. In order to fix the file layout, we
-// need to scan relocations.
-template <>
-void InputSection<E>::scan_relocations(Context<E> &ctx) {
-  assert(shdr().sh_flags & SHF_ALLOC);
-
-  this->reldyn_offset = file.num_dynrel * sizeof(ElfRel<E>);
-  std::span<const ElfRel<E>> rels = get_rels(ctx);
-
-  // Scan relocations
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
-      continue;
-
-    Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-    u8 *loc = (u8 *)(contents.data() + rel.r_offset);
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
-    if (sym.is_ifunc())
-      sym.flags |= NEEDS_GOT | NEEDS_PLT;
-
-    switch (rel.r_type) {
-    case R_X86_64_8:
-    case R_X86_64_16:
-    case R_X86_64_32:
-    case R_X86_64_32S:
-      scan_absrel(ctx, sym, rel);
-      break;
-    case R_X86_64_64:
-      scan_dyn_absrel(ctx, sym, rel);
-      break;
-    case R_X86_64_PC8:
-    case R_X86_64_PC16:
-    case R_X86_64_PC32:
-    case R_X86_64_PC64:
-      scan_pcrel(ctx, sym, rel);
-      break;
-    case R_X86_64_GOT32:
-    case R_X86_64_GOT64:
-    case R_X86_64_GOTPC32:
-    case R_X86_64_GOTPC64:
-    case R_X86_64_GOTPCREL:
-    case R_X86_64_GOTPCREL64:
-      sym.flags |= NEEDS_GOT;
-      break;
-    case R_X86_64_GOTPCRELX: {
-      if (rel.r_addend != -4)
-        Fatal(ctx) << *this << ": bad r_addend for R_X86_64_GOTPCRELX";
-
-      // We always want to relax GOTX relocations because the static
-      // PIE relies on this relaxation.
-      bool do_relax = !sym.is_imported && sym.is_relative() &&
-                      relax_gotpcrelx(loc - 2);
-      if (!do_relax)
-        sym.flags |= NEEDS_GOT;
-      break;
-    }
-    case R_X86_64_REX_GOTPCRELX: {
-      if (rel.r_addend != -4)
-        Fatal(ctx) << *this << ": bad r_addend for R_X86_64_REX_GOTPCRELX";
-
-      bool do_relax = !sym.is_imported && sym.is_relative() &&
-                      relax_rex_gotpcrelx(loc - 3);
-      if (!do_relax)
-        sym.flags |= NEEDS_GOT;
-      break;
-    }
-    case R_X86_64_PLT32:
-    case R_X86_64_PLTOFF64:
-      if (sym.is_imported)
-        sym.flags |= NEEDS_PLT;
-      break;
-    case R_X86_64_TLSGD:
-      if (rel.r_addend != -4)
-        Fatal(ctx) << *this << ": bad r_addend for R_X86_64_TLSGD";
-
-      if (i + 1 == rels.size())
-        Fatal(ctx) << *this << ": TLSGD reloc must be followed by PLT or GOTPCREL";
-
-      if (u32 ty = rels[i + 1].r_type;
-          ty != R_X86_64_PLT32 && ty != R_X86_64_PC32 &&
-          ty != R_X86_64_PLTOFF64 && ty != R_X86_64_GOTPCREL &&
-          ty != R_X86_64_GOTPCRELX)
-        Fatal(ctx) << *this << ": TLSGD reloc must be followed by PLT or GOTPCREL";
-
-      if (ctx.arg.is_static ||
-          (ctx.arg.relax && !sym.is_imported && !ctx.arg.shared)) {
-        // We always relax if -static because libc.a doesn't contain
-        // __tls_get_addr().
-        i++;
-      } else if (ctx.arg.relax && !sym.is_imported && ctx.arg.shared &&
-                 !ctx.arg.z_dlopen) {
-        sym.flags |= NEEDS_GOTTP;
-        i++;
-      } else {
-        sym.flags |= NEEDS_TLSGD;
-      }
-      break;
-    case R_X86_64_TLSLD:
-      if (rel.r_addend != -4)
-        Fatal(ctx) << *this << ": bad r_addend for R_X86_64_TLSLD";
-
-      if (i + 1 == rels.size())
-        Fatal(ctx) << *this << ": TLSLD reloc must be followed by PLT or GOTPCREL";
-
-      if (u32 ty = rels[i + 1].r_type;
-          ty != R_X86_64_PLT32 && ty != R_X86_64_PC32 &&
-          ty != R_X86_64_PLTOFF64 && ty != R_X86_64_GOTPCREL &&
-          ty != R_X86_64_GOTPCRELX)
-        Fatal(ctx) << *this << ": TLSLD reloc must be followed by PLT or GOTPCREL";
-
-      // We always relax if -static because libc.a doesn't contain
-      // __tls_get_addr().
-      if (ctx.arg.is_static || (ctx.arg.relax && !ctx.arg.shared))
-        i++;
-      else
-        ctx.needs_tlsld = true;
-      break;
-    case R_X86_64_GOTTPOFF: {
-      if (rel.r_addend != -4)
-        Fatal(ctx) << *this << ": bad r_addend for R_X86_64_GOTTPOFF";
-
-      bool do_relax = ctx.arg.relax && !ctx.arg.shared &&
-                      !sym.is_imported && relax_gottpoff(loc - 3);
-      if (!do_relax)
-        sym.flags |= NEEDS_GOTTP;
-      break;
-    }
-    case R_X86_64_GOTPC32_TLSDESC: {
-      if (rel.r_addend != -4)
-        Fatal(ctx) << *this << ": bad r_addend for R_X86_64_GOTPC32_TLSDESC";
-
-      if (relax_gotpc32_tlsdesc(loc - 3) == 0)
-        Fatal(ctx) << *this << ": GOTPC32_TLSDESC relocation is used"
-                   << " against an invalid code sequence";
-
-      if (!relax_tlsdesc(ctx, sym))
-        sym.flags |= NEEDS_TLSDESC;
-      break;
-    }
-    case R_X86_64_TPOFF32:
-    case R_X86_64_TPOFF64:
-      check_tlsle(ctx, sym, rel);
-      break;
-    case R_X86_64_GOTOFF64:
-    case R_X86_64_DTPOFF32:
-    case R_X86_64_DTPOFF64:
-    case R_X86_64_SIZE32:
-    case R_X86_64_SIZE64:
-    case R_X86_64_TLSDESC_CALL:
-      break;
-    default:
-      Error(ctx) << *this << ": unknown relocation: " << rel;
-    }
-  }
-}
-
-} // namespace mold::elf

elf/dwarf.cc

@@ -1,554 +0,0 @@
-// This file contains code to read DWARF debug info to create .gdb_index.
-//
-// .gdb_index is an optional section to speed up GNU debugger. It contains
-// two maps: 1) a map from function/variable/type names to compunits, and
-// 2) a map from function address ranges to compunits. gdb uses these
-// maps to quickly find a compunit given a name or an instruction pointer.
-//
-// (Terminology: a compilation unit, which often abbreviated as compunit
-// or cu, is a unit of debug info. An input .debug_info section usually
-// contains one compunit, and thus an output .debug_info contains as
-// many compunits as the number of input files.)
-//
-// .gdb_index is not mandatory. All the information in .gdb_index is
-// also in other debug info sections. You can actually create an
-// executable without .gdb_index and later add it using `gdb-add-index`
-// post-processing tool that comes with gdb.
-//
-// The mapping from names to compunits is 1:n while the mapping from
-// address ranges to compunits is 1:1. That is, two object files may
-// define the same type name (with the same definition), while there
-// should be no two functions that overlap with each other in memory.
-//
-// .gdb_index contains an on-disk hash table for names, so gdb can
-// lookup names without loading all strings into memory and construct an
-// in-memory hash table.
-//
-// Names are in .debug_gnu_pubnames and .debug_gnu_pubtypes input
-// sections. These sections are created if `-ggnu-pubnames` is given.
-// Besides names, these sections contains attributes for each name so
-// that gdb can distinguish type names from function names, for example.
-//
-// A compunit contains one or more function address ranges. If an
-// object file is compiled without -ffunction-sections, it contains
-// only one .text section and therefore contains a single address range.
-// Such range is typically stored directly to the compunit.
-//
-// If an object file is compiled with -fucntion-sections, it contains
-// more than one .text section, and it has as many address ranges as
-// the number of .text sections. Such discontiguous address ranges are
-// stored to .debug_ranges in DWARF 2/3/4/5 and
-// .debug_rnglists/.debug_addr in DWARF 5.
-//
-// .debug_info section contains DWARF debug info. Although we don't need
-// to parse the whole .debug_info section to read address ranges, we
-// have to do a little bit. DWARF is complicated and often handled using
-// a library such as libdwarf. But we don't use any library because we
-// don't want to add an extra run-time dependency just for --gdb-index.
-//
-// This page explains the format of .gdb_index:
-// https://sourceware.org/gdb/onlinedocs/gdb/Index-Section-Format.html
-
-#include "mold.h"
-
-namespace mold::elf {
-
-// The hash function for .gdb_index.
-static u32 gdb_hash(std::string_view name) {
-  u32 h = 0;
-  for (u8 c : name) {
-    if ('A' <= c && c <= 'Z')
-      c = 'a' + c - 'A';
-    h = h * 67 + c - 113;
-  }
-  return h;
-}
-
-// Split .debug_info into so-called "compilation units". A .debug_info
-// section usually contains one compunit unless it was created by `ld -r`.
-// This is for --gdb-index.
-template <typename E>
-std::vector<std::string_view>
-read_compunits(Context<E> &ctx, ObjectFile<E> &file) {
-  file.debug_info->uncompress(ctx);
-  std::string_view data = file.debug_info->contents;
-  std::vector<std::string_view> vec;
-
-  while (!data.empty()) {
-    if (data.size() < 4)
-      Fatal(ctx) << *file.debug_info << ": corrupted .debug_info";
-    if (*(U32<E> *)data.data() == 0xffff'ffff)
-      Fatal(ctx) << *file.debug_info << ": --gdb-index: DWARF64 not supported";
-    i64 len = *(U32<E> *)data.data() + 4;
-    vec.push_back(data.substr(0, len));
-    data = data.substr(len);
-  }
-  return vec;
-}
-
-// Parses .debug_gnu_pubnames and .debug_gnu_pubtypes. These sections
-// start with a 14 bytes header followed by (4-byte offset, 1-byte type,
-// null-terminated string) tuples.
-//
-// The 4-byte offset is an offset into .debug_info that contains details
-// about the name. The 1-byte type is a type of the corresponding name
-// (e.g. function, variable or datatype). The string is a name of a
-// function, a variable or a type.
-template <typename E>
-std::vector<GdbIndexName> read_pubnames(Context<E> &ctx, ObjectFile<E> &file) {
-  std::vector<GdbIndexName> vec;
-
-  auto get_cu_idx = [&](InputSection<E> &isec, i64 offset) {
-    i64 off = 0;
-    for (i64 i = 0; i < file.compunits.size(); i++) {
-      if (offset == off)
-        return file.compunits_idx + i;
-      off += file.compunits[i].size();
-    }
-    Fatal(ctx) << isec << ": corrupted debug_info_offset";
-  };
-
-  auto read = [&](InputSection<E> &isec) {
-    isec.uncompress(ctx);
-    std::string_view contents = isec.contents;
-
-    while (!contents.empty()) {
-      if (contents.size() < 14)
-        Fatal(ctx) << isec << ": corrupted header";
-
-      u32 len = *(U32<E> *)contents.data() + 4;
-      u32 debug_info_offset = *(U32<E> *)(contents.data() + 6);
-      u32 cu_idx = get_cu_idx(isec, debug_info_offset);
-
-      std::string_view data = contents.substr(14, len - 14);
-      contents = contents.substr(len);
-
-      while (!data.empty()) {
-        u32 offset = *(U32<E> *)data.data();
-        data = data.substr(4);
-        if (offset == 0)
-          break;
-
-        u8 type = data[0];
-        data = data.substr(1);
-
-        std::string_view name = data.data();
-        data = data.substr(name.size() + 1);
-
-        vec.push_back({name, gdb_hash(name), (type << 24) | cu_idx});
-      }
-    }
-  };
-
-  if (file.debug_pubnames)
-    read(*file.debug_pubnames);
-  if (file.debug_pubtypes)
-    read(*file.debug_pubtypes);
-
-  // Uniquify elements because GCC 11 seems to emit one record for each
-  // comdat group which results in having a lot of duplicate records.
-  auto less = [](const GdbIndexName &a, const GdbIndexName &b) {
-    return std::tuple{a.hash, a.attr, a.name} <
-           std::tuple{b.hash, b.attr, b.name};
-  };
-
-  auto equal = [](const GdbIndexName &a, const GdbIndexName &b) {
-    return std::tuple{a.hash, a.attr, a.name} ==
-           std::tuple{b.hash, b.attr, b.name};
-  };
-
-  std::sort(vec.begin(), vec.end(), less);
-  vec.erase(std::unique(vec.begin(), vec.end(), equal), vec.end());
-  return vec;
-}
-
-template <typename E>
-static u8 *get_buffer(Context<E> &ctx, Chunk<E> *chunk) {
-  if (u8 *buf = chunk->get_uncompressed_data())
-    return buf;
-  return ctx.buf + chunk->shdr.sh_offset;
-}
-
-// Try to find a compilation unit from .debug_info and its
-// corresponding record from .debug_abbrev and returns them.
-template <typename E>
-static std::tuple<u8 *, u8 *, u32>
-find_compunit(Context<E> &ctx, ObjectFile<E> &file, i64 offset) {
-  // Read .debug_info to find the record at a given offset.
-  u8 *cu = get_buffer(ctx, ctx.debug_info) + offset;
-  u32 dwarf_version = *(U16<E> *)(cu + 4);
-  u32 abbrev_offset;
-
-  // Skip a header.
-  switch (dwarf_version) {
-  case 2:
-  case 3:
-  case 4:
-    abbrev_offset = *(U32<E> *)(cu + 6);
-    if (u32 address_size = cu[10]; address_size != sizeof(Word<E>))
-      Fatal(ctx) << file << ": --gdb-index: unsupported address size "
-                 << address_size;
-    cu += 11;
-    break;
-  case 5: {
-    abbrev_offset = *(U32<E> *)(cu + 8);
-    if (u32 address_size = cu[7]; address_size != sizeof(Word<E>))
-      Fatal(ctx) << file << ": --gdb-index: unsupported address size "
-                 << address_size;
-
-    switch (u32 unit_type = cu[6]; unit_type) {
-    case DW_UT_compile:
-    case DW_UT_partial:
-      cu += 12;
-      break;
-    case DW_UT_skeleton:
-    case DW_UT_split_compile:
-      cu += 20;
-      break;
-    default:
-      Fatal(ctx) << file << ": --gdb-index: unknown DW_UT_* value: 0x"
-                 << std::hex << unit_type;
-    }
-    break;
-  }
-  default:
-    Fatal(ctx) << file << ": --gdb-index: unknown DWARF version: "
-               << dwarf_version;
-  }
-
-  u32 abbrev_code = read_uleb(cu);
-
-  // Find a .debug_abbrev record corresponding to the .debug_info record.
-  // We assume the .debug_info record at a given offset is of
-  // DW_TAG_compile_unit which describes a compunit.
-  u8 *abbrev = get_buffer(ctx, ctx.debug_abbrev) + abbrev_offset;
-
-  for (;;) {
-    u32 code = read_uleb(abbrev);
-    if (code == 0)
-      Fatal(ctx) << file << ": --gdb-index: .debug_abbrev does not contain"
-                 << " a record for the first .debug_info record";
-
-    if (code == abbrev_code) {
-      // Found a record
-      u64 abbrev_tag = read_uleb(abbrev);
-      if (abbrev_tag != DW_TAG_compile_unit && abbrev_tag != DW_TAG_skeleton_unit)
-        Fatal(ctx) << file << ": --gdb-index: the first entry's tag is not"
-                   << " DW_TAG_compile_unit/DW_TAG_skeleton_unit but 0x"
-                   << std::hex << abbrev_tag;
-      break;
-    }
-
-    // Skip an uninteresting record
-    read_uleb(abbrev); // tag
-    abbrev++; // has_children byte
-    for (;;) {
-      u64 name = read_uleb(abbrev);
-      u64 form = read_uleb(abbrev);
-      if (name == 0 && form == 0)
-        break;
-      if (form == DW_FORM_implicit_const)
-        read_uleb(abbrev);
-    }
-  }
-
-  abbrev++; // skip has_children byte
-  return {cu, abbrev, dwarf_version};
-}
-
-// Estimate the number of address ranges contained in a given file.
-// It may over-estimate but never under-estimate.
-template <typename E>
-i64 estimate_address_areas(Context<E> &ctx, ObjectFile<E> &file) {
-  // Each CU contains zero or one address area.
-  i64 ret = file.compunits.size();
-
-  // In DWARF 4, a CU can refer address ranges in .debug_ranges.
-  // .debug_ranges contains a vector of [begin, end) address pairs.
-  // The last entry must be a null terminator, so we do -1.
-  if (file.debug_ranges)
-    ret += file.debug_ranges->sh_size / sizeof(Word<E>) / 2 - 1;
-
-  // In DWARF 5, a CU can refer address ranges in .debug_rnglists, which
-  // contains variable-length entries. The smallest possible range entry
-  // is one byte for the code and two ULEB128 values (each can be as
-  // small as one byte), so 3 bytes.
-  if (file.debug_rnglists)
-    ret += file.debug_rnglists->sh_size / 3;
-  return ret;
-}
-
-// .debug_info contains variable-length fields. This class reads them.
-template <typename E>
-class DebugInfoReader {
-public:
-  DebugInfoReader(Context<E> &ctx, ObjectFile<E> &file, u8 *cu)
-    : ctx(ctx), file(file), cu(cu) {}
-
-  u64 read(u64 form);
-
-  Context<E> &ctx;
-  ObjectFile<E> &file;
-  u8 *cu;
-};
-
-// Read value of the given DW_FORM_* form. If a value is not scalar,
-// returns a dummy value 0.
-template <typename E>
-u64 DebugInfoReader<E>::read(u64 form) {
-  switch (form) {
-  case DW_FORM_flag_present:
-    return 0;
-  case DW_FORM_data1:
-  case DW_FORM_flag:
-  case DW_FORM_strx1:
-  case DW_FORM_addrx1:
-  case DW_FORM_ref1:
-    return *cu++;
-  case DW_FORM_data2:
-  case DW_FORM_strx2:
-  case DW_FORM_addrx2:
-  case DW_FORM_ref2: {
-    u64 val = *(U16<E> *)cu;
-    cu += 2;
-    return val;
-  }
-  case DW_FORM_strx3:
-  case DW_FORM_addrx3: {
-    u64 val = *(U24<E> *)cu;
-    cu += 3;
-    return val;
-  }
-  case DW_FORM_data4:
-  case DW_FORM_strp:
-  case DW_FORM_sec_offset:
-  case DW_FORM_line_strp:
-  case DW_FORM_strx4:
-  case DW_FORM_addrx4:
-  case DW_FORM_ref4: {
-    u64 val = *(U32<E> *)cu;
-    cu += 4;
-    return val;
-  }
-  case DW_FORM_data8:
-  case DW_FORM_ref8: {
-    u64 val = *(U64<E> *)cu;
-    cu += 8;
-    return val;
-  }
-  case DW_FORM_addr:
-  case DW_FORM_ref_addr: {
-    u64 val = *(Word<E> *)cu;
-    cu += sizeof(Word<E>);
-    return val;
-  }
-  case DW_FORM_strx:
-  case DW_FORM_addrx:
-  case DW_FORM_udata:
-  case DW_FORM_ref_udata:
-  case DW_FORM_loclistx:
-  case DW_FORM_rnglistx:
-    return read_uleb(cu);
-  case DW_FORM_string:
-    cu += strlen((char *)cu) + 1;
-    return 0;
-  default:
-    Fatal(ctx) << file << ": --gdb-index: unhandled debug info form: 0x"
-               << std::hex << form;
-    return 0;
-  }
-}
-
-// Read a range list from .debug_ranges starting at the given offset.
-template <typename E>
-static std::vector<u64>
-read_debug_range(Context<E> &ctx, ObjectFile<E> &file, Word<E> *range) {
-  std::vector<u64> vec;
-  u64 base = 0;
-
-  for (i64 i = 0; range[i] || range[i + 1]; i += 2) {
-    if (range[i] + 1 == 0) {
-      // base address selection entry
-      base = range[i + 1];
-    } else {
-      vec.push_back(range[i] + base);
-      vec.push_back(range[i + 1] + base);
-    }
-  }
-  return vec;
-}
-
-// Read a range list from .debug_rnglists starting at the given offset.
-template <typename E>
-static std::vector<u64>
-read_rnglist_range(Context<E> &ctx, ObjectFile<E> &file, u8 *rnglist,
-                   Word<E> *addrx) {
-  std::vector<u64> vec;
-  u64 base = 0;
-
-  for (;;) {
-    switch (*rnglist++) {
-    case DW_RLE_end_of_list:
-      return vec;
-    case DW_RLE_base_addressx:
-      base = addrx[read_uleb(rnglist)];
-      break;
-    case DW_RLE_startx_endx:
-      vec.push_back(addrx[read_uleb(rnglist)]);
-      vec.push_back(addrx[read_uleb(rnglist)]);
-      break;
-    case DW_RLE_startx_length:
-      vec.push_back(addrx[read_uleb(rnglist)]);
-      vec.push_back(vec.back() + read_uleb(rnglist));
-      break;
-    case DW_RLE_offset_pair:
-      vec.push_back(base + read_uleb(rnglist));
-      vec.push_back(base + read_uleb(rnglist));
-      break;
-    case DW_RLE_base_address:
-      base = *(Word<E> *)rnglist;
-      rnglist += sizeof(Word<E>);
-      break;
-    case DW_RLE_start_end:
-      vec.push_back(*(Word<E> *)rnglist);
-      rnglist += sizeof(Word<E>);
-      vec.push_back(*(Word<E> *)rnglist);
-      rnglist += sizeof(Word<E>);
-      break;
-    case DW_RLE_start_length:
-      vec.push_back(*(Word<E> *)rnglist);
-      rnglist += sizeof(Word<E>);
-      vec.push_back(vec.back() + read_uleb(rnglist));
-      break;
-    }
-  }
-}
-
-// Returns a list of address ranges explained by a compunit at the
-// `offset` in an output .debug_info section.
-//
-// .debug_info contains DWARF debug info records, so this function
-// parses DWARF. If a designated compunit contains multiple ranges, the
-// ranges are read from .debug_ranges (or .debug_rnglists for DWARF5).
-// Otherwise, a range is read directly from .debug_info (or possibly
-// from .debug_addr for DWARF5).
-template <typename E>
-std::vector<u64>
-read_address_areas(Context<E> &ctx, ObjectFile<E> &file, i64 offset) {
-  u8 *cu;
-  u8 *abbrev;
-  u32 dwarf_version;
-  std::tie(cu, abbrev, dwarf_version) = find_compunit(ctx, file, offset);
-
-  DebugInfoReader<E> reader{ctx, file, cu};
-
-  struct Record {
-    u64 form = 0;
-    u64 value = 0;
-  };
-
-  Record low_pc;
-  Record high_pc;
-  Record ranges;
-  std::optional<u64> rnglists_base;
-  Word<E> *addrx = nullptr;
-
-  // Read all interesting debug records.
-  for (;;) {
-    u64 name = read_uleb(abbrev);
-    u64 form = read_uleb(abbrev);
-    if (name == 0 && form == 0)
-      break;
-
-    u64 val = reader.read(form);
-
-    switch (name) {
-    case DW_AT_low_pc:
-      low_pc = {form, val};
-      break;
-    case DW_AT_high_pc:
-      high_pc = {form, val};
-      break;
-    case DW_AT_rnglists_base:
-      rnglists_base = val;
-      break;
-    case DW_AT_addr_base:
-      addrx = (Word<E> *)(get_buffer(ctx, ctx.debug_addr) + val);
-      break;
-    case DW_AT_ranges:
-      ranges = {form, val};
-      break;
-    }
-  }
-
-  // Handle non-contiguous address ranges.
-  if (ranges.form) {
-    if (dwarf_version <= 4) {
-       Word<E> *range_begin =
-        (Word<E> *)(get_buffer(ctx, ctx.debug_ranges) + ranges.value);
-      return read_debug_range(ctx, file, range_begin);
-    }
-
-    assert(dwarf_version == 5);
-
-    u8 *buf = get_buffer(ctx, ctx.debug_rnglists);
-    if (ranges.form == DW_FORM_sec_offset)
-      return read_rnglist_range(ctx, file, buf + ranges.value, addrx);
-
-    if (!rnglists_base)
-      Fatal(ctx) << file << ": --gdb-index: missing DW_AT_rnglists_base";
-
-    u8 *base = buf + *rnglists_base;
-    return read_rnglist_range(ctx, file, base + *(U32<E> *)base, addrx);
-  }
-
-  // Handle a contiguous address range.
-  if (low_pc.form && high_pc.form) {
-    u64 lo;
-
-    switch (low_pc.form) {
-    case DW_FORM_addr:
-      lo = low_pc.value;
-      break;
-    case DW_FORM_addrx:
-    case DW_FORM_addrx1:
-    case DW_FORM_addrx2:
-    case DW_FORM_addrx4:
-      lo = addrx[low_pc.value];
-      break;
-    default:
-      Fatal(ctx) << file << ": --gdb-index: unhandled form for DW_AT_low_pc: 0x"
-                 << std::hex << high_pc.form;
-    }
-
-    switch (high_pc.form) {
-    case DW_FORM_addr:
-      return {lo, high_pc.value};
-    case DW_FORM_addrx:
-    case DW_FORM_addrx1:
-    case DW_FORM_addrx2:
-    case DW_FORM_addrx4:
-      return {lo, addrx[high_pc.value]};
-    case DW_FORM_udata:
-    case DW_FORM_data1:
-    case DW_FORM_data2:
-    case DW_FORM_data4:
-    case DW_FORM_data8:
-      return {lo, lo + high_pc.value};
-    default:
-      Fatal(ctx) << file << ": --gdb-index: unhandled form for DW_AT_high_pc: 0x"
-                 << std::hex << high_pc.form;
-    }
-  }
-
-  return {};
-}
-
-using E = MOLD_TARGET;
-
-template std::vector<std::string_view> read_compunits(Context<E> &, ObjectFile<E> &);
-template std::vector<GdbIndexName> read_pubnames(Context<E> &, ObjectFile<E> &);
-template i64 estimate_address_areas(Context<E> &, ObjectFile<E> &);
-template std::vector<u64> read_address_areas(Context<E> &, ObjectFile<E> &, i64);
-
-} // namespace mold::elf

elf/elf-main.cc

@@ -1,767 +0,0 @@
-#include "mold.h"
-#include "../common/archive-file.h"
-#include "../common/cmdline.h"
-#include "../common/output-file.h"
-
-#include <cstring>
-#include <functional>
-#include <iomanip>
-#include <map>
-#include <regex>
-#include <signal.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <tbb/global_control.h>
-#include <tbb/parallel_for_each.h>
-#include <unordered_set>
-
-#ifdef _WIN32
-# include <direct.h>
-# define _chdir chdir
-#else
-# include <unistd.h>
-#endif
-
-namespace mold::elf {
-
-// Read the beginning of a given file and returns its machine type
-// (e.g. EM_X86_64 or EM_386).
-template <typename E>
-std::string_view get_machine_type(Context<E> &ctx, MappedFile<Context<E>> *mf) {
-  auto get_elf_type = [&](u8 *buf) -> std::string_view {
-    bool is_le = (((ElfEhdr<I386> *)buf)->e_ident[EI_DATA] == ELFDATA2LSB);
-    bool is_64;
-    u32 e_machine;
-
-    if (is_le) {
-      auto &ehdr = *(ElfEhdr<I386> *)buf;
-      is_64 = (ehdr.e_ident[EI_CLASS] == ELFCLASS64);
-      e_machine = ehdr.e_machine;
-    } else {
-      auto &ehdr = *(ElfEhdr<M68K> *)buf;
-      is_64 = (ehdr.e_ident[EI_CLASS] == ELFCLASS64);
-      e_machine = ehdr.e_machine;
-    }
-
-    switch (e_machine) {
-    case EM_386:
-      return I386::target_name;
-    case EM_X86_64:
-      return X86_64::target_name;
-    case EM_ARM:
-      return ARM32::target_name;
-    case EM_AARCH64:
-      return ARM64::target_name;
-    case EM_RISCV:
-      if (is_le)
-        return is_64 ? RV64LE::target_name : RV32LE::target_name;
-      return is_64 ? RV64BE::target_name : RV32BE::target_name;
-    case EM_PPC:
-      return PPC32::target_name;
-    case EM_PPC64:
-      return is_le ? PPC64V2::target_name : PPC64V1::target_name;
-    case EM_S390X:
-      return S390X::target_name;
-    case EM_SPARC64:
-      return SPARC64::target_name;
-    case EM_68K:
-      return M68K::target_name;
-    case EM_SH:
-      return SH4::target_name;
-    case EM_ALPHA:
-      return ALPHA::target_name;
-    default:
-      return "";
-    }
-  };
-
-  switch (get_file_type(ctx, mf)) {
-  case FileType::ELF_OBJ:
-  case FileType::ELF_DSO:
-  case FileType::GCC_LTO_OBJ:
-    return get_elf_type(mf->data);
-  case FileType::AR:
-    for (MappedFile<Context<E>> *child : read_fat_archive_members(ctx, mf))
-      if (get_file_type(ctx, child) == FileType::ELF_OBJ)
-        return get_elf_type(child->data);
-    return "";
-  case FileType::THIN_AR:
-    for (MappedFile<Context<E>> *child : read_thin_archive_members(ctx, mf))
-      if (get_file_type(ctx, child) == FileType::ELF_OBJ)
-        return get_elf_type(child->data);
-    return "";
-  case FileType::TEXT:
-    return get_script_output_type(ctx, mf);
-  default:
-    return "";
-  }
-}
-
-template <typename E>
-static void
-check_file_compatibility(Context<E> &ctx, MappedFile<Context<E>> *mf) {
-  std::string_view target = get_machine_type(ctx, mf);
-  if (target != ctx.arg.emulation)
-    Fatal(ctx) << mf->name << ": incompatible file type: "
-               << ctx.arg.emulation << " is expected but got " << target;
-}
-
-template <typename E>
-static ObjectFile<E> *new_object_file(Context<E> &ctx, MappedFile<Context<E>> *mf,
-                                      std::string archive_name) {
-  static Counter count("parsed_objs");
-  count++;
-
-  check_file_compatibility(ctx, mf);
-
-  bool in_lib = ctx.in_lib || (!archive_name.empty() && !ctx.whole_archive);
-  ObjectFile<E> *file = ObjectFile<E>::create(ctx, mf, archive_name, in_lib);
-  file->priority = ctx.file_priority++;
-  ctx.tg.run([file, &ctx] { file->parse(ctx); });
-  if (ctx.arg.trace)
-    SyncOut(ctx) << "trace: " << *file;
-  return file;
-}
-
-template <typename E>
-static ObjectFile<E> *new_lto_obj(Context<E> &ctx, MappedFile<Context<E>> *mf,
-                                  std::string archive_name) {
-  static Counter count("parsed_lto_objs");
-  count++;
-
-  if (ctx.arg.ignore_ir_file.count(mf->get_identifier()))
-    return nullptr;
-
-  ObjectFile<E> *file = read_lto_object(ctx, mf);
-  file->priority = ctx.file_priority++;
-  file->archive_name = archive_name;
-  file->is_in_lib = ctx.in_lib || (!archive_name.empty() && !ctx.whole_archive);
-  file->is_alive = !file->is_in_lib;
-  ctx.has_lto_object = true;
-  if (ctx.arg.trace)
-    SyncOut(ctx) << "trace: " << *file;
-  return file;
-}
-
-template <typename E>
-static SharedFile<E> *
-new_shared_file(Context<E> &ctx, MappedFile<Context<E>> *mf) {
-  check_file_compatibility(ctx, mf);
-
-  SharedFile<E> *file = SharedFile<E>::create(ctx, mf);
-  file->priority = ctx.file_priority++;
-  ctx.tg.run([file, &ctx] { file->parse(ctx); });
-  if (ctx.arg.trace)
-    SyncOut(ctx) << "trace: " << *file;
-  return file;
-}
-
-template <typename E>
-void read_file(Context<E> &ctx, MappedFile<Context<E>> *mf) {
-  if (ctx.visited.contains(mf->name))
-    return;
-
-  switch (get_file_type(ctx, mf)) {
-  case FileType::ELF_OBJ:
-    ctx.objs.push_back(new_object_file(ctx, mf, ""));
-    return;
-  case FileType::ELF_DSO:
-    ctx.dsos.push_back(new_shared_file(ctx, mf));
-    ctx.visited.insert(mf->name);
-    return;
-  case FileType::AR:
-  case FileType::THIN_AR:
-    for (MappedFile<Context<E>> *child : read_archive_members(ctx, mf)) {
-      switch (get_file_type(ctx, child)) {
-      case FileType::ELF_OBJ:
-        ctx.objs.push_back(new_object_file(ctx, child, mf->name));
-        break;
-      case FileType::GCC_LTO_OBJ:
-      case FileType::LLVM_BITCODE:
-        if (ObjectFile<E> *file = new_lto_obj(ctx, child, mf->name))
-          ctx.objs.push_back(file);
-        break;
-      default:
-        break;
-      }
-    }
-    ctx.visited.insert(mf->name);
-    return;
-  case FileType::TEXT:
-    parse_linker_script(ctx, mf);
-    return;
-  case FileType::GCC_LTO_OBJ:
-  case FileType::LLVM_BITCODE:
-    if (ObjectFile<E> *file = new_lto_obj(ctx, mf, ""))
-      ctx.objs.push_back(file);
-    return;
-  default:
-    Fatal(ctx) << mf->name << ": unknown file type";
-  }
-}
-
-template <typename E>
-static std::string_view
-deduce_machine_type(Context<E> &ctx, std::span<std::string> args) {
-  for (std::string_view arg : args)
-    if (!arg.starts_with('-'))
-      if (auto *mf = MappedFile<Context<E>>::open(ctx, std::string(arg)))
-        if (std::string_view target = get_machine_type(ctx, mf);
-            !target.empty())
-          return target;
-  Fatal(ctx) << "-m option is missing";
-}
-
-template <typename E>
-MappedFile<Context<E>> *open_library(Context<E> &ctx, std::string path) {
-  MappedFile<Context<E>> *mf = MappedFile<Context<E>>::open(ctx, path);
-  if (!mf)
-    return nullptr;
-
-  std::string_view target = get_machine_type(ctx, mf);
-  if (target.empty() || target == E::target_name)
-    return mf;
-  Warn(ctx) << path << ": skipping incompatible file " << target
-            << " " << (int)E::e_machine;
-  return nullptr;
-}
-
-template <typename E>
-MappedFile<Context<E>> *find_library(Context<E> &ctx, std::string name) {
-  if (name.starts_with(':')) {
-    for (std::string_view dir : ctx.arg.library_paths) {
-      std::string path = std::string(dir) + "/" + name.substr(1);
-      if (MappedFile<Context<E>> *mf = open_library(ctx, path))
-        return mf;
-    }
-    Fatal(ctx) << "library not found: " << name;
-  }
-
-  for (std::string_view dir : ctx.arg.library_paths) {
-    std::string stem = std::string(dir) + "/lib" + name;
-    if (!ctx.is_static)
-      if (MappedFile<Context<E>> *mf = open_library(ctx, stem + ".so"))
-        return mf;
-    if (MappedFile<Context<E>> *mf = open_library(ctx, stem + ".a"))
-      return mf;
-  }
-  Fatal(ctx) << "library not found: " << name;
-}
-
-template <typename E>
-MappedFile<Context<E>> *find_from_search_paths(Context<E> &ctx, std::string name) {
-  if (MappedFile<Context<E>> *mf = MappedFile<Context<E>>::open(ctx, name))
-    return mf;
-
-  for (std::string_view dir : ctx.arg.library_paths)
-    if (MappedFile<Context<E>> *mf =
-        MappedFile<Context<E>>::open(ctx, std::string(dir) + "/" + name))
-      return mf;
-  return nullptr;
-}
-
-template <typename E>
-static void read_input_files(Context<E> &ctx, std::span<std::string> args) {
-  Timer t(ctx, "read_input_files");
-
-  std::vector<std::tuple<bool, bool, bool, bool>> state;
-  ctx.is_static = ctx.arg.is_static;
-
-  while (!args.empty()) {
-    std::string_view arg = args[0];
-    args = args.subspan(1);
-
-    if (arg == "--as-needed") {
-      ctx.as_needed = true;
-    } else if (arg == "--no-as-needed") {
-      ctx.as_needed = false;
-    } else if (arg == "--whole-archive") {
-      ctx.whole_archive = true;
-    } else if (arg == "--no-whole-archive") {
-      ctx.whole_archive = false;
-    } else if (arg == "--Bstatic") {
-      ctx.is_static = true;
-    } else if (arg == "--Bdynamic") {
-      ctx.is_static = false;
-    } else if (arg == "--start-lib") {
-      ctx.in_lib = true;
-    } else if (arg == "--end-lib") {
-      ctx.in_lib = false;
-    } else if (remove_prefix(arg, "--version-script=")) {
-      MappedFile<Context<E>> *mf = find_from_search_paths(ctx, std::string(arg));
-      if (!mf)
-        Fatal(ctx) << "--version-script: file not found: " << arg;
-      parse_version_script(ctx, mf);
-    } else if (remove_prefix(arg, "--dynamic-list=")) {
-      MappedFile<Context<E>> *mf = find_from_search_paths(ctx, std::string(arg));
-      if (!mf)
-        Fatal(ctx) << "--dynamic-list: file not found: " << arg;
-      parse_dynamic_list(ctx, mf);
-    } else if (remove_prefix(arg, "--export-dynamic-symbol=")) {
-      if (arg == "*")
-        ctx.default_version = VER_NDX_GLOBAL;
-      else
-        ctx.version_patterns.push_back({arg, "--export-dynamic-symbol",
-                                        "global", VER_NDX_GLOBAL, false});
-    } else if (remove_prefix(arg, "--export-dynamic-symbol-list=")) {
-      MappedFile<Context<E>> *mf = find_from_search_paths(ctx, std::string(arg));
-      if (!mf)
-        Fatal(ctx) << "--export-dynamic-symbol-list: file not found: " << arg;
-      parse_dynamic_list(ctx, mf);
-    } else if (arg == "--push-state") {
-      state.push_back({ctx.as_needed, ctx.whole_archive, ctx.is_static,
-                       ctx.in_lib});
-    } else if (arg == "--pop-state") {
-      if (state.empty())
-        Fatal(ctx) << "no state pushed before popping";
-      std::tie(ctx.as_needed, ctx.whole_archive, ctx.is_static, ctx.in_lib) =
-        state.back();
-      state.pop_back();
-    } else if (remove_prefix(arg, "-l")) {
-      MappedFile<Context<E>> *mf = find_library(ctx, std::string(arg));
-      mf->given_fullpath = false;
-      read_file(ctx, mf);
-    } else {
-      read_file(ctx, MappedFile<Context<E>>::must_open(ctx, std::string(arg)));
-    }
-  }
-
-  if (ctx.objs.empty())
-    Fatal(ctx) << "no input files";
-
-  ctx.tg.wait();
-}
-
-// Since elf_main is a template, we can't run it without a type parameter.
-// We speculatively run elf_main with X86_64, and if the speculation was
-// wrong, re-run it with an actual machine type.
-template <typename E>
-static int redo_main(int argc, char **argv, std::string_view target) {
-  if (target == I386::target_name)
-    return elf_main<I386>(argc, argv);
-  if (target == ARM64::target_name)
-    return elf_main<ARM64>(argc, argv);
-  if (target == ARM32::target_name)
-    return elf_main<ARM32>(argc, argv);
-  if (target == RV64LE::target_name)
-    return elf_main<RV64LE>(argc, argv);
-  if (target == RV64BE::target_name)
-    return elf_main<RV64BE>(argc, argv);
-  if (target == RV32LE::target_name)
-    return elf_main<RV32LE>(argc, argv);
-  if (target == RV32BE::target_name)
-    return elf_main<RV32BE>(argc, argv);
-  if (target == PPC32::target_name)
-    return elf_main<PPC32>(argc, argv);
-  if (target == PPC64V1::target_name)
-    return elf_main<PPC64V1>(argc, argv);
-  if (target == PPC64V2::target_name)
-    return elf_main<PPC64V2>(argc, argv);
-  if (target == S390X::target_name)
-    return elf_main<S390X>(argc, argv);
-  if (target == SPARC64::target_name)
-    return elf_main<SPARC64>(argc, argv);
-  if (target == M68K::target_name)
-    return elf_main<M68K>(argc, argv);
-  if (target == SH4::target_name)
-    return elf_main<SH4>(argc, argv);
-  if (target == ALPHA::target_name)
-    return elf_main<ALPHA>(argc, argv);
-  unreachable();
-}
-
-template <typename E>
-int elf_main(int argc, char **argv) {
-  Context<E> ctx;
-
-  // Process -run option first. process_run_subcommand() does not return.
-  if (argc >= 2 && (argv[1] == "-run"sv || argv[1] == "--run"sv)) {
-#if defined(_WIN32) || defined(__APPLE__)
-    Fatal(ctx) << "-run is supported only on Unix";
-#endif
-    process_run_subcommand(ctx, argc, argv);
-  }
-
-  // Parse non-positional command line options
-  ctx.cmdline_args = expand_response_files(ctx, argv);
-  std::vector<std::string> file_args = parse_nonpositional_args(ctx);
-
-  // If no -m option is given, deduce it from input files.
-  if (ctx.arg.emulation.empty())
-    ctx.arg.emulation = deduce_machine_type(ctx, file_args);
-
-  // Redo if -m is not x86-64.
-  if constexpr (is_x86_64<E>)
-    if (ctx.arg.emulation != X86_64::target_name)
-      return redo_main<E>(argc, argv, ctx.arg.emulation);
-
-  Timer t_all(ctx, "all");
-
-  install_signal_handler();
-
-  if (!ctx.arg.directory.empty())
-    if (chdir(ctx.arg.directory.c_str()) == -1)
-      Fatal(ctx) << "chdir failed: " << ctx.arg.directory
-                 << ": " << errno_string();
-
-  // Fork a subprocess unless --no-fork is given.
-  std::function<void()> on_complete;
-
-#if !defined(_WIN32) && !defined(__APPLE__)
-  if (ctx.arg.fork)
-    on_complete = fork_child();
-#endif
-
-  tbb::global_control tbb_cont(tbb::global_control::max_allowed_parallelism,
-                               ctx.arg.thread_count);
-
-  // Handle --wrap options if any.
-  for (std::string_view name : ctx.arg.wrap)
-    get_symbol(ctx, name)->is_wrapped = true;
-
-  // Handle --retain-symbols-file options if any.
-  if (ctx.arg.retain_symbols_file)
-    for (std::string_view name : *ctx.arg.retain_symbols_file)
-      get_symbol(ctx, name)->write_to_symtab = true;
-
-  for (std::string_view arg : ctx.arg.trace_symbol)
-    get_symbol(ctx, arg)->is_traced = true;
-
-  // Parse input files
-  read_input_files(ctx, file_args);
-
-  // Uniquify shared object files by soname
-  {
-    std::unordered_set<std::string_view> seen;
-    std::erase_if(ctx.dsos, [&](SharedFile<E> *file) {
-      return !seen.insert(file->soname).second;
-    });
-  }
-
-  Timer t_total(ctx, "total");
-  Timer t_before_copy(ctx, "before_copy");
-
-  // Apply -exclude-libs
-  apply_exclude_libs(ctx);
-
-  // Create a dummy file containing linker-synthesized symbols.
-  if (!ctx.arg.relocatable)
-    create_internal_file(ctx);
-
-  // resolve_symbols is 4 things in 1 phase:
-  //
-  // - Determine the set of object files to extract from archives.
-  // - Remove redundant COMDAT sections (e.g. duplicate inline functions).
-  // - Finally, the actual symbol resolution.
-  // - LTO, which requires preliminary symbol resolution before running
-  //   and a follow-up re-resolution after the LTO objects are emitted.
-  //
-  // These passes have complex interactions, and unfortunately has to be
-  // put together in a single phase.
-  resolve_symbols(ctx);
-
-  // Resolve mergeable section pieces to merge them.
-  resolve_section_pieces(ctx);
-
-  // Handle --relocatable. Since the linker's behavior is quite different
-  // from the normal one when the option is given, the logic is implemented
-  // to a separate file.
-  if (ctx.arg.relocatable) {
-    combine_objects(ctx);
-    return 0;
-  }
-
-  // Create .bss sections for common symbols.
-  convert_common_symbols(ctx);
-
-  // Apply version scripts.
-  apply_version_script(ctx);
-
-  // Parse symbol version suffixes (e.g. "foo@ver1").
-  parse_symbol_version(ctx);
-
-  // Set is_imported and is_exported bits for each symbol.
-  compute_import_export(ctx);
-
-  // Read address-significant section information.
-  if (ctx.arg.icf && !ctx.arg.icf_all)
-    mark_addrsig(ctx);
-
-  // Garbage-collect unreachable sections.
-  if (ctx.arg.gc_sections)
-    gc_sections(ctx);
-
-  // Merge identical read-only sections.
-  if (ctx.arg.icf)
-    icf_sections(ctx);
-
-  // Compute sizes of sections containing mergeable strings.
-  compute_merged_section_sizes(ctx);
-
-  // Create linker-synthesized sections such as .got or .plt.
-  create_synthetic_sections(ctx);
-
-  // Make sure that there's no duplicate symbol
-  if (!ctx.arg.allow_multiple_definition)
-    check_duplicate_symbols(ctx);
-
-  // Warn if symbols with different types are defined under the same name.
-  check_symbol_types(ctx);
-
-  if constexpr (is_ppc64v1<E>)
-    ppc64v1_rewrite_opd(ctx);
-
-  // Bin input sections into output sections.
-  create_output_sections(ctx);
-
-  // Add synthetic symbols such as __ehdr_start or __end.
-  add_synthetic_symbols(ctx);
-
-  // Beyond this point, no new files will be added to ctx.objs
-  // or ctx.dsos.
-
-  // Handle `-z cet-report`.
-  if (ctx.arg.z_cet_report != CET_REPORT_NONE)
-    check_cet_errors(ctx);
-
-  // Handle `-z execstack-if-needed`.
-  if (ctx.arg.z_execstack_if_needed)
-    for (ObjectFile<E> *file : ctx.objs)
-      if (file->needs_executable_stack)
-        ctx.arg.z_execstack = true;
-
-  // If we are linking a .so file, remaining undefined symbols does
-  // not cause a linker error. Instead, they are treated as if they
-  // were imported symbols.
-  //
-  // If we are linking an executable, weak undefs are converted to
-  // weakly imported symbols so that they'll have another chance to be
-  // resolved.
-  claim_unresolved_symbols(ctx);
-
-  // Beyond this point, no new symbols will be added to the result.
-
-  // Handle --print-dependencies
-  if (ctx.arg.print_dependencies)
-    print_dependencies(ctx);
-
-  // Handle -repro
-  if (ctx.arg.repro)
-    write_repro_file(ctx);
-
-  // Handle --require-defined
-  for (std::string_view name : ctx.arg.require_defined)
-    if (!get_symbol(ctx, name)->file)
-      Error(ctx) << "--require-defined: undefined symbol: " << name;
-
-  // .init_array and .fini_array contents have to be sorted by
-  // a special rule. Sort them.
-  sort_init_fini(ctx);
-
-  // Likewise, .ctors and .dtors have to be sorted. They are rare
-  // because they are superceded by .init_array/.fini_array, though.
-  sort_ctor_dtor(ctx);
-
-  // Handle --shuffle-sections
-  if (ctx.arg.shuffle_sections != SHUFFLE_SECTIONS_NONE)
-    shuffle_sections(ctx);
-
-  // Copy string referred by .dynamic to .dynstr.
-  for (SharedFile<E> *file : ctx.dsos)
-    ctx.dynstr->add_string(file->soname);
-  for (std::string_view str : ctx.arg.auxiliary)
-    ctx.dynstr->add_string(str);
-  for (std::string_view str : ctx.arg.filter)
-    ctx.dynstr->add_string(str);
-  if (!ctx.arg.rpaths.empty())
-    ctx.dynstr->add_string(ctx.arg.rpaths);
-  if (!ctx.arg.soname.empty())
-    ctx.dynstr->add_string(ctx.arg.soname);
-
-  if constexpr (is_ppc64v1<E>)
-    ppc64v1_scan_symbols(ctx);
-
-  // Scan relocations to find symbols that need entries in .got, .plt,
-  // .got.plt, .dynsym, .dynstr, etc.
-  scan_relocations(ctx);
-
-  // Compute sizes of output sections while assigning offsets
-  // within an output section to input sections.
-  compute_section_sizes(ctx);
-
-  // Sort sections by section attributes so that we'll have to
-  // create as few segments as possible.
-  sort_output_sections(ctx);
-
-  // If --packed_dyn_relocs=relr was given, base relocations are stored
-  // to a .relr.dyn section in a compressed form. Construct a compressed
-  // relocations now so that we can fix section sizes and file layout.
-  if (ctx.arg.pack_dyn_relocs_relr)
-    construct_relr(ctx);
-
-  // Reserve a space for dynamic symbol strings in .dynstr and sort
-  // .dynsym contents if necessary. Beyond this point, no symbol will
-  // be added to .dynsym.
-  ctx.dynsym->finalize(ctx);
-
-  // Print reports about undefined symbols, if needed.
-  if (ctx.arg.unresolved_symbols == UNRESOLVED_ERROR)
-    report_undef_errors(ctx);
-
-  // Fill .gnu.version_d section contents.
-  if (ctx.verdef)
-    ctx.verdef->construct(ctx);
-
-  // Fill .gnu.version_r section contents.
-  ctx.verneed->construct(ctx);
-
-  // Compute .symtab and .strtab sizes for each file.
-  create_output_symtab(ctx);
-
-  // .eh_frame is a special section from the linker's point of view,
-  // as its contents are parsed and reconstructed by the linker,
-  // unlike other sections that are regarded as opaque bytes.
-  // Here, we construct output .eh_frame contents.
-  ctx.eh_frame->construct(ctx);
-
-  // Handle --gdb-index.
-  if (ctx.arg.gdb_index)
-    ctx.gdb_index->construct(ctx);
-
-  // If --emit-relocs is given, we'll copy relocation sections from input
-  // files to an output file.
-  if (ctx.arg.emit_relocs)
-    create_reloc_sections(ctx);
-
-  // Compute the section header values for all sections.
-  compute_section_headers(ctx);
-
-  // Assign offsets to output sections
-  i64 filesize = set_osec_offsets(ctx);
-
-  // On RISC-V, branches are encode using multiple instructions so
-  // that they can jump to anywhere in ±2 GiB by default. They may
-  // be replaced with shorter instruction sequences if destinations
-  // are close enough. Do this optimization.
-  if constexpr (is_riscv<E>)
-    filesize = riscv_resize_sections(ctx);
-
-  // At this point, memory layout is fixed.
-
-  // Set actual addresses to linker-synthesized symbols.
-  fix_synthetic_symbols(ctx);
-
-  // Beyond this, you can assume that symbol addresses including their
-  // GOT or PLT addresses have a correct final value.
-
-  // If --compress-debug-sections is given, compress .debug_* sections
-  // using zlib.
-  if (ctx.arg.compress_debug_sections != COMPRESS_NONE)
-    filesize = compress_debug_sections(ctx);
-
-  // At this point, both memory and file layouts are fixed.
-
-  t_before_copy.stop();
-
-  // Create an output file
-  ctx.output_file =
-    OutputFile<Context<E>>::open(ctx, ctx.arg.output, filesize, 0777);
-  ctx.buf = ctx.output_file->buf;
-
-  Timer t_copy(ctx, "copy");
-
-  // Copy input sections to the output file and apply relocations.
-  copy_chunks(ctx);
-
-  // Some part of .gdb_index couldn't be computed until other debug
-  // sections are complete. We have complete debug sections now, so
-  // write the rest of .gdb_index.
-  if (ctx.gdb_index)
-    ctx.gdb_index->write_address_areas(ctx);
-
-  // Dynamic linker works better with sorted .rela.dyn section,
-  // so we sort them.
-  ctx.reldyn->sort(ctx);
-
-  // Zero-clear paddings between sections
-  clear_padding(ctx);
-
-  // .note.gnu.build-id section contains a cryptographic hash of the
-  // entire output file. Now that we wrote everything except build-id,
-  // we can compute it.
-  if (ctx.buildid)
-    ctx.buildid->write_buildid(ctx);
-
-  t_copy.stop();
-  ctx.checkpoint();
-
-  // Close the output file. This is the end of the linker's main job.
-  ctx.output_file->close(ctx);
-
-  // Handle --dependency-file
-  if (!ctx.arg.dependency_file.empty())
-    write_dependency_file(ctx);
-
-  if (ctx.has_lto_object)
-    lto_cleanup(ctx);
-
-  t_total.stop();
-  t_all.stop();
-
-  if (ctx.arg.print_map)
-    print_map(ctx);
-
-  // Show stats numbers
-  if (ctx.arg.stats)
-    show_stats(ctx);
-
-  if (ctx.arg.perf)
-    print_timer_records(ctx.timer_records);
-
-  std::cout << std::flush;
-  std::cerr << std::flush;
-  if (on_complete)
-    on_complete();
-
-  if (ctx.arg.quick_exit)
-    _exit(0);
-
-  for (std::function<void()> &fn : ctx.on_exit)
-    fn();
-  ctx.checkpoint();
-  return 0;
-}
-
-using E = MOLD_TARGET;
-
-template void read_file(Context<E> &, MappedFile<Context<E>> *);
-
-#ifdef MOLD_X86_64
-
-extern template int elf_main<I386>(int, char **);
-extern template int elf_main<ARM32>(int, char **);
-extern template int elf_main<ARM64>(int, char **);
-extern template int elf_main<RV32BE>(int, char **);
-extern template int elf_main<RV32LE>(int, char **);
-extern template int elf_main<RV64LE>(int, char **);
-extern template int elf_main<RV64BE>(int, char **);
-extern template int elf_main<PPC32>(int, char **);
-extern template int elf_main<PPC64V1>(int, char **);
-extern template int elf_main<PPC64V2>(int, char **);
-extern template int elf_main<S390X>(int, char **);
-extern template int elf_main<SPARC64>(int, char **);
-extern template int elf_main<M68K>(int, char **);
-extern template int elf_main<SH4>(int, char **);
-extern template int elf_main<ALPHA>(int, char **);
-
-int main(int argc, char **argv) {
-  return elf_main<X86_64>(argc, argv);
-}
-
-#else
-
-template int elf_main<E>(int, char **);
-
-#endif
-
-} // namespace mold::elf

elf/elf.cc

@@ -1,914 +0,0 @@
-#include "mold.h"
-
-namespace mold::elf {
-
-template <>
-std::string rel_to_string<X86_64>(u32 r_type) {
-  switch (r_type) {
-  case R_X86_64_NONE: return "R_X86_64_NONE";
-  case R_X86_64_64: return "R_X86_64_64";
-  case R_X86_64_PC32: return "R_X86_64_PC32";
-  case R_X86_64_GOT32: return "R_X86_64_GOT32";
-  case R_X86_64_PLT32: return "R_X86_64_PLT32";
-  case R_X86_64_COPY: return "R_X86_64_COPY";
-  case R_X86_64_GLOB_DAT: return "R_X86_64_GLOB_DAT";
-  case R_X86_64_JUMP_SLOT: return "R_X86_64_JUMP_SLOT";
-  case R_X86_64_RELATIVE: return "R_X86_64_RELATIVE";
-  case R_X86_64_GOTPCREL: return "R_X86_64_GOTPCREL";
-  case R_X86_64_32: return "R_X86_64_32";
-  case R_X86_64_32S: return "R_X86_64_32S";
-  case R_X86_64_16: return "R_X86_64_16";
-  case R_X86_64_PC16: return "R_X86_64_PC16";
-  case R_X86_64_8: return "R_X86_64_8";
-  case R_X86_64_PC8: return "R_X86_64_PC8";
-  case R_X86_64_DTPMOD64: return "R_X86_64_DTPMOD64";
-  case R_X86_64_DTPOFF64: return "R_X86_64_DTPOFF64";
-  case R_X86_64_TPOFF64: return "R_X86_64_TPOFF64";
-  case R_X86_64_TLSGD: return "R_X86_64_TLSGD";
-  case R_X86_64_TLSLD: return "R_X86_64_TLSLD";
-  case R_X86_64_DTPOFF32: return "R_X86_64_DTPOFF32";
-  case R_X86_64_GOTTPOFF: return "R_X86_64_GOTTPOFF";
-  case R_X86_64_TPOFF32: return "R_X86_64_TPOFF32";
-  case R_X86_64_PC64: return "R_X86_64_PC64";
-  case R_X86_64_GOTOFF64: return "R_X86_64_GOTOFF64";
-  case R_X86_64_GOTPC32: return "R_X86_64_GOTPC32";
-  case R_X86_64_GOT64: return "R_X86_64_GOT64";
-  case R_X86_64_GOTPCREL64: return "R_X86_64_GOTPCREL64";
-  case R_X86_64_GOTPC64: return "R_X86_64_GOTPC64";
-  case R_X86_64_GOTPLT64: return "R_X86_64_GOTPLT64";
-  case R_X86_64_PLTOFF64: return "R_X86_64_PLTOFF64";
-  case R_X86_64_SIZE32: return "R_X86_64_SIZE32";
-  case R_X86_64_SIZE64: return "R_X86_64_SIZE64";
-  case R_X86_64_GOTPC32_TLSDESC: return "R_X86_64_GOTPC32_TLSDESC";
-  case R_X86_64_TLSDESC_CALL: return "R_X86_64_TLSDESC_CALL";
-  case R_X86_64_TLSDESC: return "R_X86_64_TLSDESC";
-  case R_X86_64_IRELATIVE: return "R_X86_64_IRELATIVE";
-  case R_X86_64_GOTPCRELX: return "R_X86_64_GOTPCRELX";
-  case R_X86_64_REX_GOTPCRELX: return "R_X86_64_REX_GOTPCRELX";
-  }
-  return "unknown (" + std::to_string(r_type) + ")";
-}
-
-template <>
-std::string rel_to_string<I386>(u32 r_type) {
-  switch (r_type) {
-  case R_386_NONE: return "R_386_NONE";
-  case R_386_32: return "R_386_32";
-  case R_386_PC32: return "R_386_PC32";
-  case R_386_GOT32: return "R_386_GOT32";
-  case R_386_PLT32: return "R_386_PLT32";
-  case R_386_COPY: return "R_386_COPY";
-  case R_386_GLOB_DAT: return "R_386_GLOB_DAT";
-  case R_386_JUMP_SLOT: return "R_386_JUMP_SLOT";
-  case R_386_RELATIVE: return "R_386_RELATIVE";
-  case R_386_GOTOFF: return "R_386_GOTOFF";
-  case R_386_GOTPC: return "R_386_GOTPC";
-  case R_386_32PLT: return "R_386_32PLT";
-  case R_386_TLS_TPOFF: return "R_386_TLS_TPOFF";
-  case R_386_TLS_IE: return "R_386_TLS_IE";
-  case R_386_TLS_GOTIE: return "R_386_TLS_GOTIE";
-  case R_386_TLS_LE: return "R_386_TLS_LE";
-  case R_386_TLS_GD: return "R_386_TLS_GD";
-  case R_386_TLS_LDM: return "R_386_TLS_LDM";
-  case R_386_16: return "R_386_16";
-  case R_386_PC16: return "R_386_PC16";
-  case R_386_8: return "R_386_8";
-  case R_386_PC8: return "R_386_PC8";
-  case R_386_TLS_GD_32: return "R_386_TLS_GD_32";
-  case R_386_TLS_GD_PUSH: return "R_386_TLS_GD_PUSH";
-  case R_386_TLS_GD_CALL: return "R_386_TLS_GD_CALL";
-  case R_386_TLS_GD_POP: return "R_386_TLS_GD_POP";
-  case R_386_TLS_LDM_32: return "R_386_TLS_LDM_32";
-  case R_386_TLS_LDM_PUSH: return "R_386_TLS_LDM_PUSH";
-  case R_386_TLS_LDM_CALL: return "R_386_TLS_LDM_CALL";
-  case R_386_TLS_LDM_POP: return "R_386_TLS_LDM_POP";
-  case R_386_TLS_LDO_32: return "R_386_TLS_LDO_32";
-  case R_386_TLS_IE_32: return "R_386_TLS_IE_32";
-  case R_386_TLS_LE_32: return "R_386_TLS_LE_32";
-  case R_386_TLS_DTPMOD32: return "R_386_TLS_DTPMOD32";
-  case R_386_TLS_DTPOFF32: return "R_386_TLS_DTPOFF32";
-  case R_386_TLS_TPOFF32: return "R_386_TLS_TPOFF32";
-  case R_386_SIZE32: return "R_386_SIZE32";
-  case R_386_TLS_GOTDESC: return "R_386_TLS_GOTDESC";
-  case R_386_TLS_DESC_CALL: return "R_386_TLS_DESC_CALL";
-  case R_386_TLS_DESC: return "R_386_TLS_DESC";
-  case R_386_IRELATIVE: return "R_386_IRELATIVE";
-  case R_386_GOT32X: return "R_386_GOT32X";
-  }
-  return "unknown (" + std::to_string(r_type) + ")";
-}
-
-template <>
-std::string rel_to_string<ARM64>(u32 r_type) {
-  switch (r_type) {
-  case R_AARCH64_NONE: return "R_AARCH64_NONE";
-  case R_AARCH64_ABS64: return "R_AARCH64_ABS64";
-  case R_AARCH64_ABS32: return "R_AARCH64_ABS32";
-  case R_AARCH64_ABS16: return "R_AARCH64_ABS16";
-  case R_AARCH64_PREL64: return "R_AARCH64_PREL64";
-  case R_AARCH64_PREL32: return "R_AARCH64_PREL32";
-  case R_AARCH64_PREL16: return "R_AARCH64_PREL16";
-  case R_AARCH64_MOVW_UABS_G0: return "R_AARCH64_MOVW_UABS_G0";
-  case R_AARCH64_MOVW_UABS_G0_NC: return "R_AARCH64_MOVW_UABS_G0_NC";
-  case R_AARCH64_MOVW_UABS_G1: return "R_AARCH64_MOVW_UABS_G1";
-  case R_AARCH64_MOVW_UABS_G1_NC: return "R_AARCH64_MOVW_UABS_G1_NC";
-  case R_AARCH64_MOVW_UABS_G2: return "R_AARCH64_MOVW_UABS_G2";
-  case R_AARCH64_MOVW_UABS_G2_NC: return "R_AARCH64_MOVW_UABS_G2_NC";
-  case R_AARCH64_MOVW_UABS_G3: return "R_AARCH64_MOVW_UABS_G3";
-  case R_AARCH64_MOVW_SABS_G0: return "R_AARCH64_MOVW_SABS_G0";
-  case R_AARCH64_MOVW_SABS_G1: return "R_AARCH64_MOVW_SABS_G1";
-  case R_AARCH64_MOVW_SABS_G2: return "R_AARCH64_MOVW_SABS_G2";
-  case R_AARCH64_LD_PREL_LO19: return "R_AARCH64_LD_PREL_LO19";
-  case R_AARCH64_ADR_PREL_LO21: return "R_AARCH64_ADR_PREL_LO21";
-  case R_AARCH64_ADR_PREL_PG_HI21: return "R_AARCH64_ADR_PREL_PG_HI21";
-  case R_AARCH64_ADR_PREL_PG_HI21_NC: return "R_AARCH64_ADR_PREL_PG_HI21_NC";
-  case R_AARCH64_ADD_ABS_LO12_NC: return "R_AARCH64_ADD_ABS_LO12_NC";
-  case R_AARCH64_LDST8_ABS_LO12_NC: return "R_AARCH64_LDST8_ABS_LO12_NC";
-  case R_AARCH64_TSTBR14: return "R_AARCH64_TSTBR14";
-  case R_AARCH64_CONDBR19: return "R_AARCH64_CONDBR19";
-  case R_AARCH64_JUMP26: return "R_AARCH64_JUMP26";
-  case R_AARCH64_CALL26: return "R_AARCH64_CALL26";
-  case R_AARCH64_LDST16_ABS_LO12_NC: return "R_AARCH64_LDST16_ABS_LO12_NC";
-  case R_AARCH64_LDST32_ABS_LO12_NC: return "R_AARCH64_LDST32_ABS_LO12_NC";
-  case R_AARCH64_LDST64_ABS_LO12_NC: return "R_AARCH64_LDST64_ABS_LO12_NC";
-  case R_AARCH64_MOVW_PREL_G0: return "R_AARCH64_MOVW_PREL_G0";
-  case R_AARCH64_MOVW_PREL_G0_NC: return "R_AARCH64_MOVW_PREL_G0_NC";
-  case R_AARCH64_MOVW_PREL_G1: return "R_AARCH64_MOVW_PREL_G1";
-  case R_AARCH64_MOVW_PREL_G1_NC: return "R_AARCH64_MOVW_PREL_G1_NC";
-  case R_AARCH64_MOVW_PREL_G2: return "R_AARCH64_MOVW_PREL_G2";
-  case R_AARCH64_MOVW_PREL_G2_NC: return "R_AARCH64_MOVW_PREL_G2_NC";
-  case R_AARCH64_MOVW_PREL_G3: return "R_AARCH64_MOVW_PREL_G3";
-  case R_AARCH64_LDST128_ABS_LO12_NC: return "R_AARCH64_LDST128_ABS_LO12_NC";
-  case R_AARCH64_ADR_GOT_PAGE: return "R_AARCH64_ADR_GOT_PAGE";
-  case R_AARCH64_LD64_GOT_LO12_NC: return "R_AARCH64_LD64_GOT_LO12_NC";
-  case R_AARCH64_LD64_GOTPAGE_LO15: return "R_AARCH64_LD64_GOTPAGE_LO15";
-  case R_AARCH64_PLT32: return "R_AARCH64_PLT32";
-  case R_AARCH64_TLSGD_ADR_PREL21: return "R_AARCH64_TLSGD_ADR_PREL21";
-  case R_AARCH64_TLSGD_ADR_PAGE21: return "R_AARCH64_TLSGD_ADR_PAGE21";
-  case R_AARCH64_TLSGD_ADD_LO12_NC: return "R_AARCH64_TLSGD_ADD_LO12_NC";
-  case R_AARCH64_TLSGD_MOVW_G1: return "R_AARCH64_TLSGD_MOVW_G1";
-  case R_AARCH64_TLSGD_MOVW_G0_NC: return "R_AARCH64_TLSGD_MOVW_G0_NC";
-  case R_AARCH64_TLSLD_ADR_PREL21: return "R_AARCH64_TLSLD_ADR_PREL21";
-  case R_AARCH64_TLSLD_ADR_PAGE21: return "R_AARCH64_TLSLD_ADR_PAGE21";
-  case R_AARCH64_TLSLD_ADD_LO12_NC: return "R_AARCH64_TLSLD_ADD_LO12_NC";
-  case R_AARCH64_TLSLD_MOVW_G1: return "R_AARCH64_TLSLD_MOVW_G1";
-  case R_AARCH64_TLSLD_MOVW_G0_NC: return "R_AARCH64_TLSLD_MOVW_G0_NC";
-  case R_AARCH64_TLSLD_LD_PREL19: return "R_AARCH64_TLSLD_LD_PREL19";
-  case R_AARCH64_TLSLD_MOVW_DTPREL_G2: return "R_AARCH64_TLSLD_MOVW_DTPREL_G2";
-  case R_AARCH64_TLSLD_MOVW_DTPREL_G1: return "R_AARCH64_TLSLD_MOVW_DTPREL_G1";
-  case R_AARCH64_TLSLD_MOVW_DTPREL_G1_NC: return "R_AARCH64_TLSLD_MOVW_DTPREL_G1_NC";
-  case R_AARCH64_TLSLD_MOVW_DTPREL_G0: return "R_AARCH64_TLSLD_MOVW_DTPREL_G0";
-  case R_AARCH64_TLSLD_MOVW_DTPREL_G0_NC: return "R_AARCH64_TLSLD_MOVW_DTPREL_G0_NC";
-  case R_AARCH64_TLSLD_ADD_DTPREL_HI12: return "R_AARCH64_TLSLD_ADD_DTPREL_HI12";
-  case R_AARCH64_TLSLD_ADD_DTPREL_LO12: return "R_AARCH64_TLSLD_ADD_DTPREL_LO12";
-  case R_AARCH64_TLSLD_ADD_DTPREL_LO12_NC: return "R_AARCH64_TLSLD_ADD_DTPREL_LO12_NC";
-  case R_AARCH64_TLSLD_LDST8_DTPREL_LO12: return "R_AARCH64_TLSLD_LDST8_DTPREL_LO12";
-  case R_AARCH64_TLSLD_LDST8_DTPREL_LO12_NC: return "R_AARCH64_TLSLD_LDST8_DTPREL_LO12_NC";
-  case R_AARCH64_TLSLD_LDST16_DTPREL_LO12: return "R_AARCH64_TLSLD_LDST16_DTPREL_LO12";
-  case R_AARCH64_TLSLD_LDST16_DTPREL_LO12_NC: return "R_AARCH64_TLSLD_LDST16_DTPREL_LO12_NC";
-  case R_AARCH64_TLSLD_LDST32_DTPREL_LO12: return "R_AARCH64_TLSLD_LDST32_DTPREL_LO12";
-  case R_AARCH64_TLSLD_LDST32_DTPREL_LO12_NC: return "R_AARCH64_TLSLD_LDST32_DTPREL_LO12_NC";
-  case R_AARCH64_TLSLD_LDST64_DTPREL_LO12: return "R_AARCH64_TLSLD_LDST64_DTPREL_LO12";
-  case R_AARCH64_TLSLD_LDST64_DTPREL_LO12_NC: return "R_AARCH64_TLSLD_LDST64_DTPREL_LO12_NC";
-  case R_AARCH64_TLSIE_MOVW_GOTTPREL_G1: return "R_AARCH64_TLSIE_MOVW_GOTTPREL_G1";
-  case R_AARCH64_TLSIE_MOVW_GOTTPREL_G0_NC: return "R_AARCH64_TLSIE_MOVW_GOTTPREL_G0_NC";
-  case R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21: return "R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21";
-  case R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC: return "R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC";
-  case R_AARCH64_TLSIE_LD_GOTTPREL_PREL19: return "R_AARCH64_TLSIE_LD_GOTTPREL_PREL19";
-  case R_AARCH64_TLSLE_MOVW_TPREL_G2: return "R_AARCH64_TLSLE_MOVW_TPREL_G2";
-  case R_AARCH64_TLSLE_MOVW_TPREL_G1: return "R_AARCH64_TLSLE_MOVW_TPREL_G1";
-  case R_AARCH64_TLSLE_MOVW_TPREL_G1_NC: return "R_AARCH64_TLSLE_MOVW_TPREL_G1_NC";
-  case R_AARCH64_TLSLE_MOVW_TPREL_G0: return "R_AARCH64_TLSLE_MOVW_TPREL_G0";
-  case R_AARCH64_TLSLE_MOVW_TPREL_G0_NC: return "R_AARCH64_TLSLE_MOVW_TPREL_G0_NC";
-  case R_AARCH64_TLSLE_ADD_TPREL_HI12: return "R_AARCH64_TLSLE_ADD_TPREL_HI12";
-  case R_AARCH64_TLSLE_ADD_TPREL_LO12: return "R_AARCH64_TLSLE_ADD_TPREL_LO12";
-  case R_AARCH64_TLSLE_ADD_TPREL_LO12_NC: return "R_AARCH64_TLSLE_ADD_TPREL_LO12_NC";
-  case R_AARCH64_TLSLE_LDST8_TPREL_LO12: return "R_AARCH64_TLSLE_LDST8_TPREL_LO12";
-  case R_AARCH64_TLSLE_LDST8_TPREL_LO12_NC: return "R_AARCH64_TLSLE_LDST8_TPREL_LO12_NC";
-  case R_AARCH64_TLSLE_LDST16_TPREL_LO12: return "R_AARCH64_TLSLE_LDST16_TPREL_LO12";
-  case R_AARCH64_TLSLE_LDST16_TPREL_LO12_NC: return "R_AARCH64_TLSLE_LDST16_TPREL_LO12_NC";
-  case R_AARCH64_TLSLE_LDST32_TPREL_LO12: return "R_AARCH64_TLSLE_LDST32_TPREL_LO12";
-  case R_AARCH64_TLSLE_LDST32_TPREL_LO12_NC: return "R_AARCH64_TLSLE_LDST32_TPREL_LO12_NC";
-  case R_AARCH64_TLSLE_LDST64_TPREL_LO12: return "R_AARCH64_TLSLE_LDST64_TPREL_LO12";
-  case R_AARCH64_TLSLE_LDST64_TPREL_LO12_NC: return "R_AARCH64_TLSLE_LDST64_TPREL_LO12_NC";
-  case R_AARCH64_TLSDESC_ADR_PAGE21: return "R_AARCH64_TLSDESC_ADR_PAGE21";
-  case R_AARCH64_TLSDESC_LD64_LO12: return "R_AARCH64_TLSDESC_LD64_LO12";
-  case R_AARCH64_TLSDESC_ADD_LO12: return "R_AARCH64_TLSDESC_ADD_LO12";
-  case R_AARCH64_TLSDESC_CALL: return "R_AARCH64_TLSDESC_CALL";
-  case R_AARCH64_TLSLE_LDST128_TPREL_LO12_NC: return "R_AARCH64_TLSLE_LDST128_TPREL_LO12_NC";
-  case R_AARCH64_COPY: return "R_AARCH64_COPY";
-  case R_AARCH64_GLOB_DAT: return "R_AARCH64_GLOB_DAT";
-  case R_AARCH64_JUMP_SLOT: return "R_AARCH64_JUMP_SLOT";
-  case R_AARCH64_RELATIVE: return "R_AARCH64_RELATIVE";
-  case R_AARCH64_TLS_DTPMOD64: return "R_AARCH64_TLS_DTPMOD64";
-  case R_AARCH64_TLS_DTPREL64: return "R_AARCH64_TLS_DTPREL64";
-  case R_AARCH64_TLS_TPREL64: return "R_AARCH64_TLS_TPREL64";
-  case R_AARCH64_TLSDESC: return "R_AARCH64_TLSDESC";
-  case R_AARCH64_IRELATIVE: return "R_AARCH64_IRELATIVE";
-  }
-  return "unknown (" + std::to_string(r_type) + ")";
-}
-
-template <>
-std::string rel_to_string<ARM32>(u32 r_type) {
-  switch (r_type) {
-  case R_ARM_NONE: return "R_ARM_NONE";
-  case R_ARM_PC24: return "R_ARM_PC24";
-  case R_ARM_ABS32: return "R_ARM_ABS32";
-  case R_ARM_REL32: return "R_ARM_REL32";
-  case R_ARM_LDR_PC_G0: return "R_ARM_LDR_PC_G0";
-  case R_ARM_ABS16: return "R_ARM_ABS16";
-  case R_ARM_ABS12: return "R_ARM_ABS12";
-  case R_ARM_THM_ABS5: return "R_ARM_THM_ABS5";
-  case R_ARM_ABS8: return "R_ARM_ABS8";
-  case R_ARM_SBREL32: return "R_ARM_SBREL32";
-  case R_ARM_THM_CALL: return "R_ARM_THM_CALL";
-  case R_ARM_THM_PC8: return "R_ARM_THM_PC8";
-  case R_ARM_BREL_ADJ: return "R_ARM_BREL_ADJ";
-  case R_ARM_TLS_DESC: return "R_ARM_TLS_DESC";
-  case R_ARM_THM_SWI8: return "R_ARM_THM_SWI8";
-  case R_ARM_XPC25: return "R_ARM_XPC25";
-  case R_ARM_THM_XPC22: return "R_ARM_THM_XPC22";
-  case R_ARM_TLS_DTPMOD32: return "R_ARM_TLS_DTPMOD32";
-  case R_ARM_TLS_DTPOFF32: return "R_ARM_TLS_DTPOFF32";
-  case R_ARM_TLS_TPOFF32: return "R_ARM_TLS_TPOFF32";
-  case R_ARM_COPY: return "R_ARM_COPY";
-  case R_ARM_GLOB_DAT: return "R_ARM_GLOB_DAT";
-  case R_ARM_JUMP_SLOT: return "R_ARM_JUMP_SLOT";
-  case R_ARM_RELATIVE: return "R_ARM_RELATIVE";
-  case R_ARM_GOTOFF32: return "R_ARM_GOTOFF32";
-  case R_ARM_BASE_PREL: return "R_ARM_BASE_PREL";
-  case R_ARM_GOT_BREL: return "R_ARM_GOT_BREL";
-  case R_ARM_PLT32: return "R_ARM_PLT32";
-  case R_ARM_CALL: return "R_ARM_CALL";
-  case R_ARM_JUMP24: return "R_ARM_JUMP24";
-  case R_ARM_THM_JUMP24: return "R_ARM_THM_JUMP24";
-  case R_ARM_BASE_ABS: return "R_ARM_BASE_ABS";
-  case R_ARM_ALU_PCREL_7_0: return "R_ARM_ALU_PCREL_7_0";
-  case R_ARM_ALU_PCREL_15_8: return "R_ARM_ALU_PCREL_15_8";
-  case R_ARM_ALU_PCREL_23_15: return "R_ARM_ALU_PCREL_23_15";
-  case R_ARM_LDR_SBREL_11_0_NC: return "R_ARM_LDR_SBREL_11_0_NC";
-  case R_ARM_ALU_SBREL_19_12_NC: return "R_ARM_ALU_SBREL_19_12_NC";
-  case R_ARM_ALU_SBREL_27_20_CK: return "R_ARM_ALU_SBREL_27_20_CK";
-  case R_ARM_TARGET1: return "R_ARM_TARGET1";
-  case R_ARM_SBREL31: return "R_ARM_SBREL31";
-  case R_ARM_V4BX: return "R_ARM_V4BX";
-  case R_ARM_TARGET2: return "R_ARM_TARGET2";
-  case R_ARM_PREL31: return "R_ARM_PREL31";
-  case R_ARM_MOVW_ABS_NC: return "R_ARM_MOVW_ABS_NC";
-  case R_ARM_MOVT_ABS: return "R_ARM_MOVT_ABS";
-  case R_ARM_MOVW_PREL_NC: return "R_ARM_MOVW_PREL_NC";
-  case R_ARM_MOVT_PREL: return "R_ARM_MOVT_PREL";
-  case R_ARM_THM_MOVW_ABS_NC: return "R_ARM_THM_MOVW_ABS_NC";
-  case R_ARM_THM_MOVT_ABS: return "R_ARM_THM_MOVT_ABS";
-  case R_ARM_THM_MOVW_PREL_NC: return "R_ARM_THM_MOVW_PREL_NC";
-  case R_ARM_THM_MOVT_PREL: return "R_ARM_THM_MOVT_PREL";
-  case R_ARM_THM_JUMP19: return "R_ARM_THM_JUMP19";
-  case R_ARM_THM_JUMP6: return "R_ARM_THM_JUMP6";
-  case R_ARM_THM_ALU_PREL_11_0: return "R_ARM_THM_ALU_PREL_11_0";
-  case R_ARM_THM_PC12: return "R_ARM_THM_PC12";
-  case R_ARM_ABS32_NOI: return "R_ARM_ABS32_NOI";
-  case R_ARM_REL32_NOI: return "R_ARM_REL32_NOI";
-  case R_ARM_ALU_PC_G0_NC: return "R_ARM_ALU_PC_G0_NC";
-  case R_ARM_ALU_PC_G0: return "R_ARM_ALU_PC_G0";
-  case R_ARM_ALU_PC_G1_NC: return "R_ARM_ALU_PC_G1_NC";
-  case R_ARM_ALU_PC_G1: return "R_ARM_ALU_PC_G1";
-  case R_ARM_ALU_PC_G2: return "R_ARM_ALU_PC_G2";
-  case R_ARM_LDR_PC_G1: return "R_ARM_LDR_PC_G1";
-  case R_ARM_LDR_PC_G2: return "R_ARM_LDR_PC_G2";
-  case R_ARM_LDRS_PC_G0: return "R_ARM_LDRS_PC_G0";
-  case R_ARM_LDRS_PC_G1: return "R_ARM_LDRS_PC_G1";
-  case R_ARM_LDRS_PC_G2: return "R_ARM_LDRS_PC_G2";
-  case R_ARM_LDC_PC_G0: return "R_ARM_LDC_PC_G0";
-  case R_ARM_LDC_PC_G1: return "R_ARM_LDC_PC_G1";
-  case R_ARM_LDC_PC_G2: return "R_ARM_LDC_PC_G2";
-  case R_ARM_ALU_SB_G0_NC: return "R_ARM_ALU_SB_G0_NC";
-  case R_ARM_ALU_SB_G0: return "R_ARM_ALU_SB_G0";
-  case R_ARM_ALU_SB_G1_NC: return "R_ARM_ALU_SB_G1_NC";
-  case R_ARM_ALU_SB_G1: return "R_ARM_ALU_SB_G1";
-  case R_ARM_ALU_SB_G2: return "R_ARM_ALU_SB_G2";
-  case R_ARM_LDR_SB_G0: return "R_ARM_LDR_SB_G0";
-  case R_ARM_LDR_SB_G1: return "R_ARM_LDR_SB_G1";
-  case R_ARM_LDR_SB_G2: return "R_ARM_LDR_SB_G2";
-  case R_ARM_LDRS_SB_G0: return "R_ARM_LDRS_SB_G0";
-  case R_ARM_LDRS_SB_G1: return "R_ARM_LDRS_SB_G1";
-  case R_ARM_LDRS_SB_G2: return "R_ARM_LDRS_SB_G2";
-  case R_ARM_LDC_SB_G0: return "R_ARM_LDC_SB_G0";
-  case R_ARM_LDC_SB_G1: return "R_ARM_LDC_SB_G1";
-  case R_ARM_LDC_SB_G2: return "R_ARM_LDC_SB_G2";
-  case R_ARM_MOVW_BREL_NC: return "R_ARM_MOVW_BREL_NC";
-  case R_ARM_MOVT_BREL: return "R_ARM_MOVT_BREL";
-  case R_ARM_MOVW_BREL: return "R_ARM_MOVW_BREL";
-  case R_ARM_THM_MOVW_BREL_NC: return "R_ARM_THM_MOVW_BREL_NC";
-  case R_ARM_THM_MOVT_BREL: return "R_ARM_THM_MOVT_BREL";
-  case R_ARM_THM_MOVW_BREL: return "R_ARM_THM_MOVW_BREL";
-  case R_ARM_TLS_GOTDESC: return "R_ARM_TLS_GOTDESC";
-  case R_ARM_TLS_CALL: return "R_ARM_TLS_CALL";
-  case R_ARM_TLS_DESCSEQ: return "R_ARM_TLS_DESCSEQ";
-  case R_ARM_THM_TLS_CALL: return "R_ARM_THM_TLS_CALL";
-  case R_ARM_PLT32_ABS: return "R_ARM_PLT32_ABS";
-  case R_ARM_GOT_ABS: return "R_ARM_GOT_ABS";
-  case R_ARM_GOT_PREL: return "R_ARM_GOT_PREL";
-  case R_ARM_GOT_BREL12: return "R_ARM_GOT_BREL12";
-  case R_ARM_GOTOFF12: return "R_ARM_GOTOFF12";
-  case R_ARM_GOTRELAX: return "R_ARM_GOTRELAX";
-  case R_ARM_GNU_VTENTRY: return "R_ARM_GNU_VTENTRY";
-  case R_ARM_GNU_VTINHERIT: return "R_ARM_GNU_VTINHERIT";
-  case R_ARM_THM_JUMP11: return "R_ARM_THM_JUMP11";
-  case R_ARM_THM_JUMP8: return "R_ARM_THM_JUMP8";
-  case R_ARM_TLS_GD32: return "R_ARM_TLS_GD32";
-  case R_ARM_TLS_LDM32: return "R_ARM_TLS_LDM32";
-  case R_ARM_TLS_LDO32: return "R_ARM_TLS_LDO32";
-  case R_ARM_TLS_IE32: return "R_ARM_TLS_IE32";
-  case R_ARM_TLS_LE32: return "R_ARM_TLS_LE32";
-  case R_ARM_TLS_LDO12: return "R_ARM_TLS_LDO12";
-  case R_ARM_TLS_LE12: return "R_ARM_TLS_LE12";
-  case R_ARM_TLS_IE12GP: return "R_ARM_TLS_IE12GP";
-  case R_ARM_PRIVATE_0: return "R_ARM_PRIVATE_0";
-  case R_ARM_PRIVATE_1: return "R_ARM_PRIVATE_1";
-  case R_ARM_PRIVATE_2: return "R_ARM_PRIVATE_2";
-  case R_ARM_PRIVATE_3: return "R_ARM_PRIVATE_3";
-  case R_ARM_PRIVATE_4: return "R_ARM_PRIVATE_4";
-  case R_ARM_PRIVATE_5: return "R_ARM_PRIVATE_5";
-  case R_ARM_PRIVATE_6: return "R_ARM_PRIVATE_6";
-  case R_ARM_PRIVATE_7: return "R_ARM_PRIVATE_7";
-  case R_ARM_PRIVATE_8: return "R_ARM_PRIVATE_8";
-  case R_ARM_PRIVATE_9: return "R_ARM_PRIVATE_9";
-  case R_ARM_PRIVATE_10: return "R_ARM_PRIVATE_10";
-  case R_ARM_PRIVATE_11: return "R_ARM_PRIVATE_11";
-  case R_ARM_PRIVATE_12: return "R_ARM_PRIVATE_12";
-  case R_ARM_PRIVATE_13: return "R_ARM_PRIVATE_13";
-  case R_ARM_PRIVATE_14: return "R_ARM_PRIVATE_14";
-  case R_ARM_PRIVATE_15: return "R_ARM_PRIVATE_15";
-  case R_ARM_ME_TOO: return "R_ARM_ME_TOO";
-  case R_ARM_THM_TLS_DESCSEQ16: return "R_ARM_THM_TLS_DESCSEQ16";
-  case R_ARM_THM_TLS_DESCSEQ32: return "R_ARM_THM_TLS_DESCSEQ32";
-  case R_ARM_THM_BF16: return "R_ARM_THM_BF16";
-  case R_ARM_THM_BF12: return "R_ARM_THM_BF12";
-  case R_ARM_THM_BF18: return "R_ARM_THM_BF18";
-  case R_ARM_IRELATIVE: return "R_ARM_IRELATIVE";
-  }
-  return "unknown (" + std::to_string(r_type) + ")";
-}
-
-template <>
-std::string rel_to_string<RV64LE>(u32 r_type) {
-  switch (r_type) {
-  case R_RISCV_NONE: return "R_RISCV_NONE";
-  case R_RISCV_32: return "R_RISCV_32";
-  case R_RISCV_64: return "R_RISCV_64";
-  case R_RISCV_RELATIVE: return "R_RISCV_RELATIVE";
-  case R_RISCV_COPY: return "R_RISCV_COPY";
-  case R_RISCV_JUMP_SLOT: return "R_RISCV_JUMP_SLOT";
-  case R_RISCV_TLS_DTPMOD32: return "R_RISCV_TLS_DTPMOD32";
-  case R_RISCV_TLS_DTPMOD64: return "R_RISCV_TLS_DTPMOD64";
-  case R_RISCV_TLS_DTPREL32: return "R_RISCV_TLS_DTPREL32";
-  case R_RISCV_TLS_DTPREL64: return "R_RISCV_TLS_DTPREL64";
-  case R_RISCV_TLS_TPREL32: return "R_RISCV_TLS_TPREL32";
-  case R_RISCV_TLS_TPREL64: return "R_RISCV_TLS_TPREL64";
-  case R_RISCV_BRANCH: return "R_RISCV_BRANCH";
-  case R_RISCV_JAL: return "R_RISCV_JAL";
-  case R_RISCV_CALL: return "R_RISCV_CALL";
-  case R_RISCV_CALL_PLT: return "R_RISCV_CALL_PLT";
-  case R_RISCV_GOT_HI20: return "R_RISCV_GOT_HI20";
-  case R_RISCV_TLS_GOT_HI20: return "R_RISCV_TLS_GOT_HI20";
-  case R_RISCV_TLS_GD_HI20: return "R_RISCV_TLS_GD_HI20";
-  case R_RISCV_PCREL_HI20: return "R_RISCV_PCREL_HI20";
-  case R_RISCV_PCREL_LO12_I: return "R_RISCV_PCREL_LO12_I";
-  case R_RISCV_PCREL_LO12_S: return "R_RISCV_PCREL_LO12_S";
-  case R_RISCV_HI20: return "R_RISCV_HI20";
-  case R_RISCV_LO12_I: return "R_RISCV_LO12_I";
-  case R_RISCV_LO12_S: return "R_RISCV_LO12_S";
-  case R_RISCV_TPREL_HI20: return "R_RISCV_TPREL_HI20";
-  case R_RISCV_TPREL_LO12_I: return "R_RISCV_TPREL_LO12_I";
-  case R_RISCV_TPREL_LO12_S: return "R_RISCV_TPREL_LO12_S";
-  case R_RISCV_TPREL_ADD: return "R_RISCV_TPREL_ADD";
-  case R_RISCV_ADD8: return "R_RISCV_ADD8";
-  case R_RISCV_ADD16: return "R_RISCV_ADD16";
-  case R_RISCV_ADD32: return "R_RISCV_ADD32";
-  case R_RISCV_ADD64: return "R_RISCV_ADD64";
-  case R_RISCV_SUB8: return "R_RISCV_SUB8";
-  case R_RISCV_SUB16: return "R_RISCV_SUB16";
-  case R_RISCV_SUB32: return "R_RISCV_SUB32";
-  case R_RISCV_SUB64: return "R_RISCV_SUB64";
-  case R_RISCV_ALIGN: return "R_RISCV_ALIGN";
-  case R_RISCV_RVC_BRANCH: return "R_RISCV_RVC_BRANCH";
-  case R_RISCV_RVC_JUMP: return "R_RISCV_RVC_JUMP";
-  case R_RISCV_RVC_LUI: return "R_RISCV_RVC_LUI";
-  case R_RISCV_RELAX: return "R_RISCV_RELAX";
-  case R_RISCV_SUB6: return "R_RISCV_SUB6";
-  case R_RISCV_SET6: return "R_RISCV_SET6";
-  case R_RISCV_SET8: return "R_RISCV_SET8";
-  case R_RISCV_SET16: return "R_RISCV_SET16";
-  case R_RISCV_SET32: return "R_RISCV_SET32";
-  case R_RISCV_32_PCREL: return "R_RISCV_32_PCREL";
-  case R_RISCV_IRELATIVE: return "R_RISCV_IRELATIVE";
-  }
-  return "unknown (" + std::to_string(r_type) + ")";
-}
-
-template <>
-std::string rel_to_string<RV64BE>(u32 r_type) {
-  return rel_to_string<RV64LE>(r_type);
-}
-
-template <>
-std::string rel_to_string<RV32LE>(u32 r_type) {
-  return rel_to_string<RV64LE>(r_type);
-}
-
-template <>
-std::string rel_to_string<RV32BE>(u32 r_type) {
-  return rel_to_string<RV64LE>(r_type);
-}
-
-template <>
-std::string rel_to_string<PPC32>(u32 r_type) {
-  switch (r_type) {
-  case R_PPC_NONE: return "R_PPC_NONE";
-  case R_PPC_ADDR32: return "R_PPC_ADDR32";
-  case R_PPC_ADDR24: return "R_PPC_ADDR24";
-  case R_PPC_ADDR16: return "R_PPC_ADDR16";
-  case R_PPC_ADDR16_LO: return "R_PPC_ADDR16_LO";
-  case R_PPC_ADDR16_HI: return "R_PPC_ADDR16_HI";
-  case R_PPC_ADDR16_HA: return "R_PPC_ADDR16_HA";
-  case R_PPC_ADDR14: return "R_PPC_ADDR14";
-  case R_PPC_ADDR14_BRTAKEN: return "R_PPC_ADDR14_BRTAKEN";
-  case R_PPC_ADDR14_BRNTAKEN: return "R_PPC_ADDR14_BRNTAKEN";
-  case R_PPC_REL24: return "R_PPC_REL24";
-  case R_PPC_REL14: return "R_PPC_REL14";
-  case R_PPC_REL14_BRTAKEN: return "R_PPC_REL14_BRTAKEN";
-  case R_PPC_REL14_BRNTAKEN: return "R_PPC_REL14_BRNTAKEN";
-  case R_PPC_GOT16: return "R_PPC_GOT16";
-  case R_PPC_GOT16_LO: return "R_PPC_GOT16_LO";
-  case R_PPC_GOT16_HI: return "R_PPC_GOT16_HI";
-  case R_PPC_GOT16_HA: return "R_PPC_GOT16_HA";
-  case R_PPC_PLTREL24: return "R_PPC_PLTREL24";
-  case R_PPC_COPY: return "R_PPC_COPY";
-  case R_PPC_GLOB_DAT: return "R_PPC_GLOB_DAT";
-  case R_PPC_JMP_SLOT: return "R_PPC_JMP_SLOT";
-  case R_PPC_RELATIVE: return "R_PPC_RELATIVE";
-  case R_PPC_LOCAL24PC: return "R_PPC_LOCAL24PC";
-  case R_PPC_UADDR32: return "R_PPC_UADDR32";
-  case R_PPC_UADDR16: return "R_PPC_UADDR16";
-  case R_PPC_REL32: return "R_PPC_REL32";
-  case R_PPC_PLT32: return "R_PPC_PLT32";
-  case R_PPC_PLTREL32: return "R_PPC_PLTREL32";
-  case R_PPC_PLT16_LO: return "R_PPC_PLT16_LO";
-  case R_PPC_PLT16_HI: return "R_PPC_PLT16_HI";
-  case R_PPC_PLT16_HA: return "R_PPC_PLT16_HA";
-  case R_PPC_SDAREL16: return "R_PPC_SDAREL16";
-  case R_PPC_SECTOFF: return "R_PPC_SECTOFF";
-  case R_PPC_SECTOFF_LO: return "R_PPC_SECTOFF_LO";
-  case R_PPC_SECTOFF_HI: return "R_PPC_SECTOFF_HI";
-  case R_PPC_SECTOFF_HA: return "R_PPC_SECTOFF_HA";
-  case R_PPC_ADDR30: return "R_PPC_ADDR30";
-  case R_PPC_TLS: return "R_PPC_TLS";
-  case R_PPC_DTPMOD32: return "R_PPC_DTPMOD32";
-  case R_PPC_TPREL16: return "R_PPC_TPREL16";
-  case R_PPC_TPREL16_LO: return "R_PPC_TPREL16_LO";
-  case R_PPC_TPREL16_HI: return "R_PPC_TPREL16_HI";
-  case R_PPC_TPREL16_HA: return "R_PPC_TPREL16_HA";
-  case R_PPC_TPREL32: return "R_PPC_TPREL32";
-  case R_PPC_DTPREL16: return "R_PPC_DTPREL16";
-  case R_PPC_DTPREL16_LO: return "R_PPC_DTPREL16_LO";
-  case R_PPC_DTPREL16_HI: return "R_PPC_DTPREL16_HI";
-  case R_PPC_DTPREL16_HA: return "R_PPC_DTPREL16_HA";
-  case R_PPC_DTPREL32: return "R_PPC_DTPREL32";
-  case R_PPC_GOT_TLSGD16: return "R_PPC_GOT_TLSGD16";
-  case R_PPC_GOT_TLSGD16_LO: return "R_PPC_GOT_TLSGD16_LO";
-  case R_PPC_GOT_TLSGD16_HI: return "R_PPC_GOT_TLSGD16_HI";
-  case R_PPC_GOT_TLSGD16_HA: return "R_PPC_GOT_TLSGD16_HA";
-  case R_PPC_GOT_TLSLD16: return "R_PPC_GOT_TLSLD16";
-  case R_PPC_GOT_TLSLD16_LO: return "R_PPC_GOT_TLSLD16_LO";
-  case R_PPC_GOT_TLSLD16_HI: return "R_PPC_GOT_TLSLD16_HI";
-  case R_PPC_GOT_TLSLD16_HA: return "R_PPC_GOT_TLSLD16_HA";
-  case R_PPC_GOT_TPREL16: return "R_PPC_GOT_TPREL16";
-  case R_PPC_GOT_TPREL16_LO: return "R_PPC_GOT_TPREL16_LO";
-  case R_PPC_GOT_TPREL16_HI: return "R_PPC_GOT_TPREL16_HI";
-  case R_PPC_GOT_TPREL16_HA: return "R_PPC_GOT_TPREL16_HA";
-  case R_PPC_GOT_DTPREL16: return "R_PPC_GOT_DTPREL16";
-  case R_PPC_GOT_DTPREL16_LO: return "R_PPC_GOT_DTPREL16_LO";
-  case R_PPC_GOT_DTPREL16_HI: return "R_PPC_GOT_DTPREL16_HI";
-  case R_PPC_GOT_DTPREL16_HA: return "R_PPC_GOT_DTPREL16_HA";
-  case R_PPC_TLSGD: return "R_PPC_TLSGD";
-  case R_PPC_TLSLD: return "R_PPC_TLSLD";
-  case R_PPC_PLTSEQ: return "R_PPC_PLTSEQ";
-  case R_PPC_PLTCALL: return "R_PPC_PLTCALL";
-  case R_PPC_IRELATIVE: return "R_PPC_IRELATIVE";
-  case R_PPC_REL16: return "R_PPC_REL16";
-  case R_PPC_REL16_LO: return "R_PPC_REL16_LO";
-  case R_PPC_REL16_HI: return "R_PPC_REL16_HI";
-  case R_PPC_REL16_HA: return "R_PPC_REL16_HA";
-  }
-  return "unknown (" + std::to_string(r_type) + ")";
-}
-
-template <>
-std::string rel_to_string<PPC64V1>(u32 r_type) {
-  switch (r_type) {
-  case R_PPC64_NONE: return "R_PPC64_NONE";
-  case R_PPC64_ADDR32: return "R_PPC64_ADDR32";
-  case R_PPC64_ADDR24: return "R_PPC64_ADDR24";
-  case R_PPC64_ADDR16: return "R_PPC64_ADDR16";
-  case R_PPC64_ADDR16_LO: return "R_PPC64_ADDR16_LO";
-  case R_PPC64_ADDR16_HI: return "R_PPC64_ADDR16_HI";
-  case R_PPC64_ADDR16_HA: return "R_PPC64_ADDR16_HA";
-  case R_PPC64_ADDR14: return "R_PPC64_ADDR14";
-  case R_PPC64_ADDR14_BRTAKEN: return "R_PPC64_ADDR14_BRTAKEN";
-  case R_PPC64_ADDR14_BRNTAKEN: return "R_PPC64_ADDR14_BRNTAKEN";
-  case R_PPC64_REL24: return "R_PPC64_REL24";
-  case R_PPC64_REL14: return "R_PPC64_REL14";
-  case R_PPC64_REL14_BRTAKEN: return "R_PPC64_REL14_BRTAKEN";
-  case R_PPC64_REL14_BRNTAKEN: return "R_PPC64_REL14_BRNTAKEN";
-  case R_PPC64_GOT16: return "R_PPC64_GOT16";
-  case R_PPC64_GOT16_LO: return "R_PPC64_GOT16_LO";
-  case R_PPC64_GOT16_HI: return "R_PPC64_GOT16_HI";
-  case R_PPC64_GOT16_HA: return "R_PPC64_GOT16_HA";
-  case R_PPC64_COPY: return "R_PPC64_COPY";
-  case R_PPC64_GLOB_DAT: return "R_PPC64_GLOB_DAT";
-  case R_PPC64_JMP_SLOT: return "R_PPC64_JMP_SLOT";
-  case R_PPC64_RELATIVE: return "R_PPC64_RELATIVE";
-  case R_PPC64_REL32: return "R_PPC64_REL32";
-  case R_PPC64_PLT16_LO: return "R_PPC64_PLT16_LO";
-  case R_PPC64_PLT16_HI: return "R_PPC64_PLT16_HI";
-  case R_PPC64_PLT16_HA: return "R_PPC64_PLT16_HA";
-  case R_PPC64_ADDR64: return "R_PPC64_ADDR64";
-  case R_PPC64_ADDR16_HIGHER: return "R_PPC64_ADDR16_HIGHER";
-  case R_PPC64_ADDR16_HIGHERA: return "R_PPC64_ADDR16_HIGHERA";
-  case R_PPC64_ADDR16_HIGHEST: return "R_PPC64_ADDR16_HIGHEST";
-  case R_PPC64_ADDR16_HIGHESTA: return "R_PPC64_ADDR16_HIGHESTA";
-  case R_PPC64_REL64: return "R_PPC64_REL64";
-  case R_PPC64_TOC16: return "R_PPC64_TOC16";
-  case R_PPC64_TOC16_LO: return "R_PPC64_TOC16_LO";
-  case R_PPC64_TOC16_HI: return "R_PPC64_TOC16_HI";
-  case R_PPC64_TOC16_HA: return "R_PPC64_TOC16_HA";
-  case R_PPC64_TOC: return "R_PPC64_TOC";
-  case R_PPC64_ADDR16_DS: return "R_PPC64_ADDR16_DS";
-  case R_PPC64_ADDR16_LO_DS: return "R_PPC64_ADDR16_LO_DS";
-  case R_PPC64_GOT16_DS: return "R_PPC64_GOT16_DS";
-  case R_PPC64_GOT16_LO_DS: return "R_PPC64_GOT16_LO_DS";
-  case R_PPC64_PLT16_LO_DS: return "R_PPC64_PLT16_LO_DS";
-  case R_PPC64_TOC16_DS: return "R_PPC64_TOC16_DS";
-  case R_PPC64_TOC16_LO_DS: return "R_PPC64_TOC16_LO_DS";
-  case R_PPC64_TLS: return "R_PPC64_TLS";
-  case R_PPC64_DTPMOD64: return "R_PPC64_DTPMOD64";
-  case R_PPC64_TPREL16: return "R_PPC64_TPREL16";
-  case R_PPC64_TPREL16_LO: return "R_PPC64_TPREL16_LO";
-  case R_PPC64_TPREL16_HI: return "R_PPC64_TPREL16_HI";
-  case R_PPC64_TPREL16_HA: return "R_PPC64_TPREL16_HA";
-  case R_PPC64_TPREL64: return "R_PPC64_TPREL64";
-  case R_PPC64_DTPREL16: return "R_PPC64_DTPREL16";
-  case R_PPC64_DTPREL16_LO: return "R_PPC64_DTPREL16_LO";
-  case R_PPC64_DTPREL16_HI: return "R_PPC64_DTPREL16_HI";
-  case R_PPC64_DTPREL16_HA: return "R_PPC64_DTPREL16_HA";
-  case R_PPC64_DTPREL64: return "R_PPC64_DTPREL64";
-  case R_PPC64_GOT_TLSGD16: return "R_PPC64_GOT_TLSGD16";
-  case R_PPC64_GOT_TLSGD16_LO: return "R_PPC64_GOT_TLSGD16_LO";
-  case R_PPC64_GOT_TLSGD16_HI: return "R_PPC64_GOT_TLSGD16_HI";
-  case R_PPC64_GOT_TLSGD16_HA: return "R_PPC64_GOT_TLSGD16_HA";
-  case R_PPC64_GOT_TLSLD16: return "R_PPC64_GOT_TLSLD16";
-  case R_PPC64_GOT_TLSLD16_LO: return "R_PPC64_GOT_TLSLD16_LO";
-  case R_PPC64_GOT_TLSLD16_HI: return "R_PPC64_GOT_TLSLD16_HI";
-  case R_PPC64_GOT_TLSLD16_HA: return "R_PPC64_GOT_TLSLD16_HA";
-  case R_PPC64_GOT_TPREL16_DS: return "R_PPC64_GOT_TPREL16_DS";
-  case R_PPC64_GOT_TPREL16_LO_DS: return "R_PPC64_GOT_TPREL16_LO_DS";
-  case R_PPC64_GOT_TPREL16_HI: return "R_PPC64_GOT_TPREL16_HI";
-  case R_PPC64_GOT_TPREL16_HA: return "R_PPC64_GOT_TPREL16_HA";
-  case R_PPC64_GOT_DTPREL16_DS: return "R_PPC64_GOT_DTPREL16_DS";
-  case R_PPC64_GOT_DTPREL16_LO_DS: return "R_PPC64_GOT_DTPREL16_LO_DS";
-  case R_PPC64_GOT_DTPREL16_HI: return "R_PPC64_GOT_DTPREL16_HI";
-  case R_PPC64_GOT_DTPREL16_HA: return "R_PPC64_GOT_DTPREL16_HA";
-  case R_PPC64_TPREL16_DS: return "R_PPC64_TPREL16_DS";
-  case R_PPC64_TPREL16_LO_DS: return "R_PPC64_TPREL16_LO_DS";
-  case R_PPC64_TPREL16_HIGHER: return "R_PPC64_TPREL16_HIGHER";
-  case R_PPC64_TPREL16_HIGHERA: return "R_PPC64_TPREL16_HIGHERA";
-  case R_PPC64_TPREL16_HIGHEST: return "R_PPC64_TPREL16_HIGHEST";
-  case R_PPC64_TPREL16_HIGHESTA: return "R_PPC64_TPREL16_HIGHESTA";
-  case R_PPC64_DTPREL16_DS: return "R_PPC64_DTPREL16_DS";
-  case R_PPC64_DTPREL16_LO_DS: return "R_PPC64_DTPREL16_LO_DS";
-  case R_PPC64_DTPREL16_HIGHER: return "R_PPC64_DTPREL16_HIGHER";
-  case R_PPC64_DTPREL16_HIGHERA: return "R_PPC64_DTPREL16_HIGHERA";
-  case R_PPC64_DTPREL16_HIGHEST: return "R_PPC64_DTPREL16_HIGHEST";
-  case R_PPC64_DTPREL16_HIGHESTA: return "R_PPC64_DTPREL16_HIGHESTA";
-  case R_PPC64_TLSGD: return "R_PPC64_TLSGD";
-  case R_PPC64_TLSLD: return "R_PPC64_TLSLD";
-  case R_PPC64_ADDR16_HIGH: return "R_PPC64_ADDR16_HIGH";
-  case R_PPC64_ADDR16_HIGHA: return "R_PPC64_ADDR16_HIGHA";
-  case R_PPC64_TPREL16_HIGH: return "R_PPC64_TPREL16_HIGH";
-  case R_PPC64_TPREL16_HIGHA: return "R_PPC64_TPREL16_HIGHA";
-  case R_PPC64_DTPREL16_HIGH: return "R_PPC64_DTPREL16_HIGH";
-  case R_PPC64_DTPREL16_HIGHA: return "R_PPC64_DTPREL16_HIGHA";
-  case R_PPC64_REL24_NOTOC: return "R_PPC64_REL24_NOTOC";
-  case R_PPC64_PLTSEQ: return "R_PPC64_PLTSEQ";
-  case R_PPC64_PLTCALL: return "R_PPC64_PLTCALL";
-  case R_PPC64_PCREL_OPT: return "R_PPC64_PCREL_OPT";
-  case R_PPC64_PCREL34: return "R_PPC64_PCREL34";
-  case R_PPC64_GOT_PCREL34: return "R_PPC64_GOT_PCREL34";
-  case R_PPC64_TPREL34: return "R_PPC64_TPREL34";
-  case R_PPC64_DTPREL34: return "R_PPC64_DTPREL34";
-  case R_PPC64_GOT_TLSGD_PCREL34: return "R_PPC64_GOT_TLSGD_PCREL34";
-  case R_PPC64_GOT_TLSLD_PCREL34: return "R_PPC64_GOT_TLSLD_PCREL34";
-  case R_PPC64_GOT_TPREL_PCREL34: return "R_PPC64_GOT_TPREL_PCREL34";
-  case R_PPC64_IRELATIVE: return "R_PPC64_IRELATIVE";
-  case R_PPC64_REL16: return "R_PPC64_REL16";
-  case R_PPC64_REL16_LO: return "R_PPC64_REL16_LO";
-  case R_PPC64_REL16_HI: return "R_PPC64_REL16_HI";
-  case R_PPC64_REL16_HA: return "R_PPC64_REL16_HA";
-  }
-  return "unknown (" + std::to_string(r_type) + ")";
-}
-
-template <>
-std::string rel_to_string<PPC64V2>(u32 r_type) {
-  return rel_to_string<PPC64V1>(r_type);
-}
-
-template <>
-std::string rel_to_string<SPARC64>(u32 r_type) {
-  switch (r_type) {
-  case R_SPARC_NONE: return "R_SPARC_NONE";
-  case R_SPARC_8: return "R_SPARC_8";
-  case R_SPARC_16: return "R_SPARC_16";
-  case R_SPARC_32: return "R_SPARC_32";
-  case R_SPARC_DISP8: return "R_SPARC_DISP8";
-  case R_SPARC_DISP16: return "R_SPARC_DISP16";
-  case R_SPARC_DISP32: return "R_SPARC_DISP32";
-  case R_SPARC_WDISP30: return "R_SPARC_WDISP30";
-  case R_SPARC_WDISP22: return "R_SPARC_WDISP22";
-  case R_SPARC_HI22: return "R_SPARC_HI22";
-  case R_SPARC_22: return "R_SPARC_22";
-  case R_SPARC_13: return "R_SPARC_13";
-  case R_SPARC_LO10: return "R_SPARC_LO10";
-  case R_SPARC_GOT10: return "R_SPARC_GOT10";
-  case R_SPARC_GOT13: return "R_SPARC_GOT13";
-  case R_SPARC_GOT22: return "R_SPARC_GOT22";
-  case R_SPARC_PC10: return "R_SPARC_PC10";
-  case R_SPARC_PC22: return "R_SPARC_PC22";
-  case R_SPARC_WPLT30: return "R_SPARC_WPLT30";
-  case R_SPARC_COPY: return "R_SPARC_COPY";
-  case R_SPARC_GLOB_DAT: return "R_SPARC_GLOB_DAT";
-  case R_SPARC_JMP_SLOT: return "R_SPARC_JMP_SLOT";
-  case R_SPARC_RELATIVE: return "R_SPARC_RELATIVE";
-  case R_SPARC_UA32: return "R_SPARC_UA32";
-  case R_SPARC_PLT32: return "R_SPARC_PLT32";
-  case R_SPARC_HIPLT22: return "R_SPARC_HIPLT22";
-  case R_SPARC_LOPLT10: return "R_SPARC_LOPLT10";
-  case R_SPARC_PCPLT32: return "R_SPARC_PCPLT32";
-  case R_SPARC_PCPLT22: return "R_SPARC_PCPLT22";
-  case R_SPARC_PCPLT10: return "R_SPARC_PCPLT10";
-  case R_SPARC_10: return "R_SPARC_10";
-  case R_SPARC_11: return "R_SPARC_11";
-  case R_SPARC_64: return "R_SPARC_64";
-  case R_SPARC_OLO10: return "R_SPARC_OLO10";
-  case R_SPARC_HH22: return "R_SPARC_HH22";
-  case R_SPARC_HM10: return "R_SPARC_HM10";
-  case R_SPARC_LM22: return "R_SPARC_LM22";
-  case R_SPARC_PC_HH22: return "R_SPARC_PC_HH22";
-  case R_SPARC_PC_HM10: return "R_SPARC_PC_HM10";
-  case R_SPARC_PC_LM22: return "R_SPARC_PC_LM22";
-  case R_SPARC_WDISP16: return "R_SPARC_WDISP16";
-  case R_SPARC_WDISP19: return "R_SPARC_WDISP19";
-  case R_SPARC_7: return "R_SPARC_7";
-  case R_SPARC_5: return "R_SPARC_5";
-  case R_SPARC_6: return "R_SPARC_6";
-  case R_SPARC_DISP64: return "R_SPARC_DISP64";
-  case R_SPARC_PLT64: return "R_SPARC_PLT64";
-  case R_SPARC_HIX22: return "R_SPARC_HIX22";
-  case R_SPARC_LOX10: return "R_SPARC_LOX10";
-  case R_SPARC_H44: return "R_SPARC_H44";
-  case R_SPARC_M44: return "R_SPARC_M44";
-  case R_SPARC_L44: return "R_SPARC_L44";
-  case R_SPARC_REGISTER: return "R_SPARC_REGISTER";
-  case R_SPARC_UA64: return "R_SPARC_UA64";
-  case R_SPARC_UA16: return "R_SPARC_UA16";
-  case R_SPARC_TLS_GD_HI22: return "R_SPARC_TLS_GD_HI22";
-  case R_SPARC_TLS_GD_LO10: return "R_SPARC_TLS_GD_LO10";
-  case R_SPARC_TLS_GD_ADD: return "R_SPARC_TLS_GD_ADD";
-  case R_SPARC_TLS_GD_CALL: return "R_SPARC_TLS_GD_CALL";
-  case R_SPARC_TLS_LDM_HI22: return "R_SPARC_TLS_LDM_HI22";
-  case R_SPARC_TLS_LDM_LO10: return "R_SPARC_TLS_LDM_LO10";
-  case R_SPARC_TLS_LDM_ADD: return "R_SPARC_TLS_LDM_ADD";
-  case R_SPARC_TLS_LDM_CALL: return "R_SPARC_TLS_LDM_CALL";
-  case R_SPARC_TLS_LDO_HIX22: return "R_SPARC_TLS_LDO_HIX22";
-  case R_SPARC_TLS_LDO_LOX10: return "R_SPARC_TLS_LDO_LOX10";
-  case R_SPARC_TLS_LDO_ADD: return "R_SPARC_TLS_LDO_ADD";
-  case R_SPARC_TLS_IE_HI22: return "R_SPARC_TLS_IE_HI22";
-  case R_SPARC_TLS_IE_LO10: return "R_SPARC_TLS_IE_LO10";
-  case R_SPARC_TLS_IE_LD: return "R_SPARC_TLS_IE_LD";
-  case R_SPARC_TLS_IE_LDX: return "R_SPARC_TLS_IE_LDX";
-  case R_SPARC_TLS_IE_ADD: return "R_SPARC_TLS_IE_ADD";
-  case R_SPARC_TLS_LE_HIX22: return "R_SPARC_TLS_LE_HIX22";
-  case R_SPARC_TLS_LE_LOX10: return "R_SPARC_TLS_LE_LOX10";
-  case R_SPARC_TLS_DTPMOD32: return "R_SPARC_TLS_DTPMOD32";
-  case R_SPARC_TLS_DTPMOD64: return "R_SPARC_TLS_DTPMOD64";
-  case R_SPARC_TLS_DTPOFF32: return "R_SPARC_TLS_DTPOFF32";
-  case R_SPARC_TLS_DTPOFF64: return "R_SPARC_TLS_DTPOFF64";
-  case R_SPARC_TLS_TPOFF32: return "R_SPARC_TLS_TPOFF32";
-  case R_SPARC_TLS_TPOFF64: return "R_SPARC_TLS_TPOFF64";
-  case R_SPARC_GOTDATA_HIX22: return "R_SPARC_GOTDATA_HIX22";
-  case R_SPARC_GOTDATA_LOX10: return "R_SPARC_GOTDATA_LOX10";
-  case R_SPARC_GOTDATA_OP_HIX22: return "R_SPARC_GOTDATA_OP_HIX22";
-  case R_SPARC_GOTDATA_OP_LOX10: return "R_SPARC_GOTDATA_OP_LOX10";
-  case R_SPARC_GOTDATA_OP: return "R_SPARC_GOTDATA_OP";
-  case R_SPARC_IRELATIVE: return "R_SPARC_IRELATIVE";
-  }
-  return "unknown (" + std::to_string(r_type) + ")";
-}
-
-template <>
-std::string rel_to_string<S390X>(u32 r_type) {
-  switch (r_type) {
-  case R_390_NONE: return "R_390_NONE";
-  case R_390_8: return "R_390_8";
-  case R_390_12: return "R_390_12";
-  case R_390_16: return "R_390_16";
-  case R_390_32: return "R_390_32";
-  case R_390_PC32: return "R_390_PC32";
-  case R_390_GOT12: return "R_390_GOT12";
-  case R_390_GOT32: return "R_390_GOT32";
-  case R_390_PLT32: return "R_390_PLT32";
-  case R_390_COPY: return "R_390_COPY";
-  case R_390_GLOB_DAT: return "R_390_GLOB_DAT";
-  case R_390_JMP_SLOT: return "R_390_JMP_SLOT";
-  case R_390_RELATIVE: return "R_390_RELATIVE";
-  case R_390_GOTOFF32: return "R_390_GOTOFF32";
-  case R_390_GOTPC: return "R_390_GOTPC";
-  case R_390_GOT16: return "R_390_GOT16";
-  case R_390_PC16: return "R_390_PC16";
-  case R_390_PC16DBL: return "R_390_PC16DBL";
-  case R_390_PLT16DBL: return "R_390_PLT16DBL";
-  case R_390_PC32DBL: return "R_390_PC32DBL";
-  case R_390_PLT32DBL: return "R_390_PLT32DBL";
-  case R_390_GOTPCDBL: return "R_390_GOTPCDBL";
-  case R_390_64: return "R_390_64";
-  case R_390_PC64: return "R_390_PC64";
-  case R_390_GOT64: return "R_390_GOT64";
-  case R_390_PLT64: return "R_390_PLT64";
-  case R_390_GOTENT: return "R_390_GOTENT";
-  case R_390_GOTOFF16: return "R_390_GOTOFF16";
-  case R_390_GOTOFF64: return "R_390_GOTOFF64";
-  case R_390_GOTPLT12: return "R_390_GOTPLT12";
-  case R_390_GOTPLT16: return "R_390_GOTPLT16";
-  case R_390_GOTPLT32: return "R_390_GOTPLT32";
-  case R_390_GOTPLT64: return "R_390_GOTPLT64";
-  case R_390_GOTPLTENT: return "R_390_GOTPLTENT";
-  case R_390_PLTOFF16: return "R_390_PLTOFF16";
-  case R_390_PLTOFF32: return "R_390_PLTOFF32";
-  case R_390_PLTOFF64: return "R_390_PLTOFF64";
-  case R_390_TLS_LOAD: return "R_390_TLS_LOAD";
-  case R_390_TLS_GDCALL: return "R_390_TLS_GDCALL";
-  case R_390_TLS_LDCALL: return "R_390_TLS_LDCALL";
-  case R_390_TLS_GD32: return "R_390_TLS_GD32";
-  case R_390_TLS_GD64: return "R_390_TLS_GD64";
-  case R_390_TLS_GOTIE12: return "R_390_TLS_GOTIE12";
-  case R_390_TLS_GOTIE32: return "R_390_TLS_GOTIE32";
-  case R_390_TLS_GOTIE64: return "R_390_TLS_GOTIE64";
-  case R_390_TLS_LDM32: return "R_390_TLS_LDM32";
-  case R_390_TLS_LDM64: return "R_390_TLS_LDM64";
-  case R_390_TLS_IE32: return "R_390_TLS_IE32";
-  case R_390_TLS_IE64: return "R_390_TLS_IE64";
-  case R_390_TLS_IEENT: return "R_390_TLS_IEENT";
-  case R_390_TLS_LE32: return "R_390_TLS_LE32";
-  case R_390_TLS_LE64: return "R_390_TLS_LE64";
-  case R_390_TLS_LDO32: return "R_390_TLS_LDO32";
-  case R_390_TLS_LDO64: return "R_390_TLS_LDO64";
-  case R_390_TLS_DTPMOD: return "R_390_TLS_DTPMOD";
-  case R_390_TLS_DTPOFF: return "R_390_TLS_DTPOFF";
-  case R_390_TLS_TPOFF: return "R_390_TLS_TPOFF";
-  case R_390_20: return "R_390_20";
-  case R_390_GOT20: return "R_390_GOT20";
-  case R_390_GOTPLT20: return "R_390_GOTPLT20";
-  case R_390_TLS_GOTIE20: return "R_390_TLS_GOTIE20";
-  case R_390_IRELATIVE: return "R_390_IRELATIVE";
-  case R_390_PC12DBL: return "R_390_PC12DBL";
-  case R_390_PLT12DBL: return "R_390_PLT12DBL";
-  case R_390_PC24DBL: return "R_390_PC24DBL";
-  case R_390_PLT24DBL: return "R_390_PLT24DBL";
-  }
-  return "unknown (" + std::to_string(r_type) + ")";
-}
-
-template <>
-std::string rel_to_string<M68K>(u32 r_type) {
-  switch (r_type) {
-  case R_68K_NONE: return "R_68K_NONE";
-  case R_68K_32: return "R_68K_32";
-  case R_68K_16: return "R_68K_16";
-  case R_68K_8: return "R_68K_8";
-  case R_68K_PC32: return "R_68K_PC32";
-  case R_68K_PC16: return "R_68K_PC16";
-  case R_68K_PC8: return "R_68K_PC8";
-  case R_68K_GOTPCREL32: return "R_68K_GOTPCREL32";
-  case R_68K_GOTPCREL16: return "R_68K_GOTPCREL16";
-  case R_68K_GOTPCREL8: return "R_68K_GOTPCREL8";
-  case R_68K_GOTOFF32: return "R_68K_GOTOFF32";
-  case R_68K_GOTOFF16: return "R_68K_GOTOFF16";
-  case R_68K_GOTOFF8: return "R_68K_GOTOFF8";
-  case R_68K_PLT32: return "R_68K_PLT32";
-  case R_68K_PLT16: return "R_68K_PLT16";
-  case R_68K_PLT8: return "R_68K_PLT8";
-  case R_68K_PLTOFF32: return "R_68K_PLTOFF32";
-  case R_68K_PLTOFF16: return "R_68K_PLTOFF16";
-  case R_68K_PLTOFF8: return "R_68K_PLTOFF8";
-  case R_68K_COPY: return "R_68K_COPY";
-  case R_68K_GLOB_DAT: return "R_68K_GLOB_DAT";
-  case R_68K_JMP_SLOT: return "R_68K_JMP_SLOT";
-  case R_68K_RELATIVE: return "R_68K_RELATIVE";
-  case R_68K_TLS_GD32: return "R_68K_TLS_GD32";
-  case R_68K_TLS_GD16: return "R_68K_TLS_GD16";
-  case R_68K_TLS_GD8: return "R_68K_TLS_GD8";
-  case R_68K_TLS_LDM32: return "R_68K_TLS_LDM32";
-  case R_68K_TLS_LDM16: return "R_68K_TLS_LDM16";
-  case R_68K_TLS_LDM8: return "R_68K_TLS_LDM8";
-  case R_68K_TLS_LDO32: return "R_68K_TLS_LDO32";
-  case R_68K_TLS_LDO16: return "R_68K_TLS_LDO16";
-  case R_68K_TLS_LDO8: return "R_68K_TLS_LDO8";
-  case R_68K_TLS_IE32: return "R_68K_TLS_IE32";
-  case R_68K_TLS_IE16: return "R_68K_TLS_IE16";
-  case R_68K_TLS_IE8: return "R_68K_TLS_IE8";
-  case R_68K_TLS_LE32: return "R_68K_TLS_LE32";
-  case R_68K_TLS_LE16: return "R_68K_TLS_LE16";
-  case R_68K_TLS_LE8: return "R_68K_TLS_LE8";
-  case R_68K_TLS_DTPMOD32: return "R_68K_TLS_DTPMOD32";
-  case R_68K_TLS_DTPREL32: return "R_68K_TLS_DTPREL32";
-  case R_68K_TLS_TPREL32: return "R_68K_TLS_TPREL32";
-  }
-  return "unknown (" + std::to_string(r_type) + ")";
-}
-
-template <>
-std::string rel_to_string<SH4>(u32 r_type) {
-  switch (r_type) {
-  case R_SH_NONE: return "R_SH_NONE";
-  case R_SH_DIR32: return "R_SH_DIR32";
-  case R_SH_REL32: return "R_SH_REL32";
-  case R_SH_DIR8WPN: return "R_SH_DIR8WPN";
-  case R_SH_IND12W: return "R_SH_IND12W";
-  case R_SH_DIR8WPL: return "R_SH_DIR8WPL";
-  case R_SH_DIR8WPZ: return "R_SH_DIR8WPZ";
-  case R_SH_DIR8BP: return "R_SH_DIR8BP";
-  case R_SH_DIR8W: return "R_SH_DIR8W";
-  case R_SH_DIR8L: return "R_SH_DIR8L";
-  case R_SH_TLS_GD_32: return "R_SH_TLS_GD_32";
-  case R_SH_TLS_LD_32: return "R_SH_TLS_LD_32";
-  case R_SH_TLS_LDO_32: return "R_SH_TLS_LDO_32";
-  case R_SH_TLS_IE_32: return "R_SH_TLS_IE_32";
-  case R_SH_TLS_LE_32: return "R_SH_TLS_LE_32";
-  case R_SH_TLS_DTPMOD32: return "R_SH_TLS_DTPMOD32";
-  case R_SH_TLS_DTPOFF32: return "R_SH_TLS_DTPOFF32";
-  case R_SH_TLS_TPOFF32: return "R_SH_TLS_TPOFF32";
-  case R_SH_GOT32: return "R_SH_GOT32";
-  case R_SH_PLT32: return "R_SH_PLT32";
-  case R_SH_COPY: return "R_SH_COPY";
-  case R_SH_GLOB_DAT: return "R_SH_GLOB_DAT";
-  case R_SH_JMP_SLOT: return "R_SH_JMP_SLOT";
-  case R_SH_RELATIVE: return "R_SH_RELATIVE";
-  case R_SH_GOTOFF: return "R_SH_GOTOFF";
-  case R_SH_GOTPC: return "R_SH_GOTPC";
-  case R_SH_GOTPLT32: return "R_SH_GOTPLT32";
-  }
-  return "unknown (" + std::to_string(r_type) + ")";
-}
-
-template <>
-std::string rel_to_string<ALPHA>(u32 r_type) {
-  switch (r_type) {
-  case R_ALPHA_NONE: return "R_ALPHA_NONE";
-  case R_ALPHA_REFLONG: return "R_ALPHA_REFLONG";
-  case R_ALPHA_REFQUAD: return "R_ALPHA_REFQUAD";
-  case R_ALPHA_GPREL32: return "R_ALPHA_GPREL32";
-  case R_ALPHA_LITERAL: return "R_ALPHA_LITERAL";
-  case R_ALPHA_LITUSE: return "R_ALPHA_LITUSE";
-  case R_ALPHA_GPDISP: return "R_ALPHA_GPDISP";
-  case R_ALPHA_BRADDR: return "R_ALPHA_BRADDR";
-  case R_ALPHA_HINT: return "R_ALPHA_HINT";
-  case R_ALPHA_SREL16: return "R_ALPHA_SREL16";
-  case R_ALPHA_SREL32: return "R_ALPHA_SREL32";
-  case R_ALPHA_SREL64: return "R_ALPHA_SREL64";
-  case R_ALPHA_GPRELHIGH: return "R_ALPHA_GPRELHIGH";
-  case R_ALPHA_GPRELLOW: return "R_ALPHA_GPRELLOW";
-  case R_ALPHA_GPREL16: return "R_ALPHA_GPREL16";
-  case R_ALPHA_COPY: return "R_ALPHA_COPY";
-  case R_ALPHA_GLOB_DAT: return "R_ALPHA_GLOB_DAT";
-  case R_ALPHA_JMP_SLOT: return "R_ALPHA_JMP_SLOT";
-  case R_ALPHA_RELATIVE: return "R_ALPHA_RELATIVE";
-  case R_ALPHA_BRSGP: return "R_ALPHA_BRSGP";
-  case R_ALPHA_TLSGD: return "R_ALPHA_TLSGD";
-  case R_ALPHA_TLSLDM: return "R_ALPHA_TLSLDM";
-  case R_ALPHA_DTPMOD64: return "R_ALPHA_DTPMOD64";
-  case R_ALPHA_GOTDTPREL: return "R_ALPHA_GOTDTPREL";
-  case R_ALPHA_DTPREL64: return "R_ALPHA_DTPREL64";
-  case R_ALPHA_DTPRELHI: return "R_ALPHA_DTPRELHI";
-  case R_ALPHA_DTPRELLO: return "R_ALPHA_DTPRELLO";
-  case R_ALPHA_DTPREL16: return "R_ALPHA_DTPREL16";
-  case R_ALPHA_GOTTPREL: return "R_ALPHA_GOTTPREL";
-  case R_ALPHA_TPREL64: return "R_ALPHA_TPREL64";
-  case R_ALPHA_TPRELHI: return "R_ALPHA_TPRELHI";
-  case R_ALPHA_TPRELLO: return "R_ALPHA_TPRELLO";
-  case R_ALPHA_TPREL16: return "R_ALPHA_TPREL16";
-  }
-  return "unknown (" + std::to_string(r_type) + ")";
-}
-
-} // namespace mold::elf

elf/gc-sections.cc

@@ -1,179 +0,0 @@
-// This file implements a mark-sweep garbage collector for -gc-sections.
-// In this algorithm, vertices are sections and edges are relocations.
-// Any section that is reachable from a root section is considered alive.
-
-#include "mold.h"
-
-#include <tbb/concurrent_vector.h>
-#include <tbb/parallel_for_each.h>
-
-namespace mold::elf {
-
-template <typename E>
-static bool should_keep(const InputSection<E> &isec) {
-  u32 type = isec.shdr().sh_type;
-  u32 flags = isec.shdr().sh_flags;
-  std::string_view name = isec.name();
-
-  return (flags & SHF_GNU_RETAIN) ||
-         type == SHT_NOTE ||
-         type == SHT_INIT_ARRAY ||
-         type == SHT_FINI_ARRAY ||
-         type == SHT_PREINIT_ARRAY ||
-         (is_arm32<E> && type == SHT_ARM_EXIDX) ||
-         name.starts_with(".ctors") ||
-         name.starts_with(".dtors") ||
-         name.starts_with(".init") ||
-         name.starts_with(".fini") ||
-         is_c_identifier(name);
-}
-
-template <typename E>
-static bool mark_section(InputSection<E> *isec) {
-  return isec && isec->is_alive && !isec->is_visited.test_and_set();
-}
-
-template <typename E>
-static void visit(Context<E> &ctx, InputSection<E> *isec,
-                  tbb::feeder<InputSection<E> *> &feeder, i64 depth) {
-  assert(isec->is_visited);
-
-  // If this is a text section, .eh_frame may contain records
-  // describing how to handle exceptions for that function.
-  // We want to keep associated .eh_frame records.
-  for (FdeRecord<E> &fde : isec->get_fdes())
-    for (const ElfRel<E> &rel : fde.get_rels(isec->file).subspan(1))
-      if (Symbol<E> *sym = isec->file.symbols[rel.r_sym])
-        if (mark_section(sym->get_input_section()))
-          feeder.add(sym->get_input_section());
-
-  for (const ElfRel<E> &rel : isec->get_rels(ctx)) {
-    Symbol<E> &sym = *isec->file.symbols[rel.r_sym];
-
-    // Symbol can refer either a section fragment or an input section.
-    // Mark a fragment as alive.
-    if (SectionFragment<E> *frag = sym.get_frag()) {
-      frag->is_alive = true;
-      continue;
-    }
-
-    // Mark a section alive. For better performacne, we don't call
-    // `feeder.add` too often.
-    if (mark_section(sym.get_input_section())) {
-      if (depth < 3)
-        visit(ctx, sym.get_input_section(), feeder, depth + 1);
-      else
-        feeder.add(sym.get_input_section());
-    }
-  }
-}
-
-template <typename E>
-static void collect_root_set(Context<E> &ctx,
-                             tbb::concurrent_vector<InputSection<E> *> &rootset) {
-  Timer t(ctx, "collect_root_set");
-
-  auto enqueue_section = [&](InputSection<E> *isec) {
-    if (mark_section(isec))
-      rootset.push_back(isec);
-  };
-
-  auto enqueue_symbol = [&](Symbol<E> *sym) {
-    if (sym) {
-      if (SectionFragment<E> *frag = sym->get_frag())
-        frag->is_alive = true;
-      else
-        enqueue_section(sym->get_input_section());
-    }
-  };
-
-  // Add sections that are not subject to garbage collection.
-  tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
-    for (std::unique_ptr<InputSection<E>> &isec : file->sections) {
-      if (!isec || !isec->is_alive)
-        continue;
-
-      // --gc-sections discards only SHF_ALLOC sections. If you want to
-      // reduce the amount of non-memory-mapped segments, you should
-      // use `strip` command, compile without debug info or use
-      // --strip-all linker option.
-      u32 flags = isec->shdr().sh_flags;
-      if (!(flags & SHF_ALLOC))
-        isec->is_visited = true;
-
-      if (should_keep(*isec))
-        enqueue_section(isec.get());
-    }
-  });
-
-  // Add sections containing exported symbols
-  tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
-    for (Symbol<E> *sym : file->symbols)
-      if (sym->file == file && sym->is_exported)
-        enqueue_symbol(sym);
-  });
-
-  // Add sections referenced by root symbols.
-  enqueue_symbol(get_symbol(ctx, ctx.arg.entry));
-
-  for (std::string_view name : ctx.arg.undefined)
-    enqueue_symbol(get_symbol(ctx, name));
-
-  for (std::string_view name : ctx.arg.require_defined)
-    enqueue_symbol(get_symbol(ctx, name));
-
-  // .eh_frame consists of variable-length records called CIE and FDE
-  // records, and they are a unit of inclusion or exclusion.
-  // We just keep all CIEs and everything that are referenced by them.
-  tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
-    for (CieRecord<E> &cie : file->cies)
-      for (const ElfRel<E> &rel : cie.get_rels())
-        enqueue_symbol(file->symbols[rel.r_sym]);
-  });
-}
-
-// Mark all reachable sections
-template <typename E>
-static void mark(Context<E> &ctx,
-                 tbb::concurrent_vector<InputSection<E> *> &rootset) {
-  Timer t(ctx, "mark");
-
-  tbb::parallel_for_each(rootset, [&](InputSection<E> *isec,
-                                    tbb::feeder<InputSection<E> *> &feeder) {
-    visit(ctx, isec, feeder, 0);
-  });
-}
-
-// Remove unreachable sections
-template <typename E>
-static void sweep(Context<E> &ctx) {
-  Timer t(ctx, "sweep");
-  static Counter counter("garbage_sections");
-
-  tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
-    for (std::unique_ptr<InputSection<E>> &isec : file->sections) {
-      if (isec && isec->is_alive && !isec->is_visited) {
-        if (ctx.arg.print_gc_sections)
-          SyncOut(ctx) << "removing unused section " << *isec;
-        isec->kill();
-        counter++;
-      }
-    }
-  });
-}
-
-template <typename E>
-void gc_sections(Context<E> &ctx) {
-  Timer t(ctx, "gc");
-
-  tbb::concurrent_vector<InputSection<E> *> rootset;
-  collect_root_set(ctx, rootset);
-  mark(ctx, rootset);
-  sweep(ctx);
-}
-
-using E = MOLD_TARGET;
-
-template void gc_sections(Context<E> &ctx);
-
-} // namespace mold::elf

elf/input-sections.cc

@@ -1,460 +0,0 @@
-#include "mold.h"
-
-#include <limits>
-#include <zlib.h>
-#include <zstd.h>
-
-namespace mold::elf {
-
-typedef enum {
-  NONE, ERROR, COPYREL, DYN_COPYREL, PLT, CPLT, DYN_CPLT, DYNREL, BASEREL, IFUNC,
-} Action;
-
-template <typename E>
-bool CieRecord<E>::equals(const CieRecord<E> &other) const {
-  if (get_contents() != other.get_contents())
-    return false;
-
-  std::span<const ElfRel<E>> x = get_rels();
-  std::span<const ElfRel<E>> y = other.get_rels();
-  if (x.size() != y.size())
-    return false;
-
-  for (i64 i = 0; i < x.size(); i++) {
-    if (x[i].r_offset - input_offset != y[i].r_offset - other.input_offset ||
-        x[i].r_type != y[i].r_type ||
-        file.symbols[x[i].r_sym] != other.file.symbols[y[i].r_sym] ||
-        get_addend(input_section, x[i]) != get_addend(other.input_section, y[i]))
-      return false;
-  }
-  return true;
-}
-
-static i64 to_p2align(u64 alignment) {
-  if (alignment == 0)
-    return 0;
-  return std::countr_zero(alignment);
-}
-
-template <typename E>
-InputSection<E>::InputSection(Context<E> &ctx, ObjectFile<E> &file,
-                              std::string_view name, i64 shndx)
-  : file(file), shndx(shndx) {
-  if (shndx < file.elf_sections.size())
-    contents = {(char *)file.mf->data + shdr().sh_offset, (size_t)shdr().sh_size};
-
-  if (shdr().sh_flags & SHF_COMPRESSED) {
-    ElfChdr<E> &chdr = *(ElfChdr<E> *)&contents[0];
-    sh_size = chdr.ch_size;
-    p2align = to_p2align(chdr.ch_addralign);
-  } else {
-    sh_size = shdr().sh_size;
-    p2align = to_p2align(shdr().sh_addralign);
-  }
-
-  // Sections may have been compressed. We usually uncompress them
-  // directly into the mmap'ed output file, but we want to uncompress
-  // early for REL-type ELF types to read relocation addends from
-  // section contents. For RELA-type, we don't need to do this because
-  // addends are in relocations.
-  //
-  // SH-4 stores addends to sections despite being RELA, which is a
-  // special (and buggy) case.
-  if constexpr (!E::is_rela || is_sh4<E>)
-    uncompress(ctx);
-}
-
-template <typename E>
-void InputSection<E>::uncompress(Context<E> &ctx) {
-  if (!(shdr().sh_flags & SHF_COMPRESSED) || uncompressed)
-    return;
-
-  u8 *buf = new u8[sh_size];
-  uncompress_to(ctx, buf);
-  contents = std::string_view((char *)buf, sh_size);
-  ctx.string_pool.emplace_back(buf);
-  uncompressed = true;
-}
-
-template <typename E>
-void InputSection<E>::uncompress_to(Context<E> &ctx, u8 *buf) {
-  if (!(shdr().sh_flags & SHF_COMPRESSED) || uncompressed) {
-    memcpy(buf, contents.data(), contents.size());
-    return;
-  }
-
-  if (contents.size() < sizeof(ElfChdr<E>))
-    Fatal(ctx) << *this << ": corrupted compressed section";
-
-  ElfChdr<E> &hdr = *(ElfChdr<E> *)&contents[0];
-  std::string_view data = contents.substr(sizeof(ElfChdr<E>));
-
-  switch (hdr.ch_type) {
-  case ELFCOMPRESS_ZLIB: {
-    unsigned long size = sh_size;
-    if (::uncompress(buf, &size, (u8 *)data.data(), data.size()) != Z_OK)
-      Fatal(ctx) << *this << ": uncompress failed";
-    assert(size == sh_size);
-    break;
-  }
-  case ELFCOMPRESS_ZSTD:
-    if (ZSTD_decompress(buf, sh_size, (u8 *)data.data(), data.size()) != sh_size)
-      Fatal(ctx) << *this << ": ZSTD_decompress failed";
-    break;
-  default:
-    Fatal(ctx) << *this << ": unsupported compression type: 0x"
-               << std::hex << hdr.ch_type;
-  }
-}
-
-template <typename E>
-static Action get_rel_action(Context<E> &ctx, Symbol<E> &sym,
-                             const Action table[3][4]) {
-  auto get_output_type = [&] {
-    if (ctx.arg.shared)
-      return 0;
-    if (ctx.arg.pie)
-      return 1;
-    return 2;
-  };
-
-  auto get_sym_type = [&] {
-    if (sym.is_absolute())
-      return 0;
-    if (!sym.is_imported)
-      return 1;
-    if (sym.get_type() != STT_FUNC)
-      return 2;
-    return 3;
-  };
-
-  return table[get_output_type()][get_sym_type()];
-}
-
-template <typename E>
-static void scan_rel(Context<E> &ctx, InputSection<E> &isec, Symbol<E> &sym,
-                     const ElfRel<E> &rel, Action action) {
-  bool writable = (isec.shdr().sh_flags & SHF_WRITE);
-
-  auto error = [&] {
-    std::string msg = sym.is_absolute() ? "-fno-PIC" : "-fPIC";
-    Error(ctx) << isec << ": " << rel << " relocation at offset 0x"
-               << std::hex << rel.r_offset << " against symbol `"
-               << sym << "' can not be used; recompile with " << msg;
-  };
-
-  auto check_textrel = [&] {
-    if (!writable) {
-      if (ctx.arg.z_text) {
-        error();
-      } else if (ctx.arg.warn_textrel) {
-        Warn(ctx) << isec << ": relocation against symbol `" << sym
-                  << "' in read-only section";
-      }
-      ctx.has_textrel = true;
-    }
-  };
-
-  auto copyrel = [&] {
-    assert(sym.is_imported);
-    if (sym.esym().st_visibility == STV_PROTECTED) {
-      Error(ctx) << isec
-                 << ": cannot make copy relocation for protected symbol '" << sym
-                 << "', defined in " << *sym.file << "; recompile with -fPIC";
-    }
-    sym.flags |= NEEDS_COPYREL;
-  };
-
-  auto dynrel = [&] {
-    check_textrel();
-    isec.file.num_dynrel++;
-  };
-
-  switch (action) {
-  case NONE:
-    break;
-  case ERROR:
-    error();
-    break;
-  case COPYREL:
-    if (!ctx.arg.z_copyreloc)
-      error();
-    copyrel();
-    break;
-  case DYN_COPYREL:
-    if (writable || !ctx.arg.z_copyreloc)
-      dynrel();
-    else
-      copyrel();
-    break;
-  case PLT:
-    sym.flags |= NEEDS_PLT;
-    break;
-  case CPLT:
-    sym.flags |= NEEDS_CPLT;
-    break;
-  case DYN_CPLT:
-    if (writable)
-      dynrel();
-    else
-      sym.flags |= NEEDS_CPLT;
-    break;
-  case DYNREL:
-    dynrel();
-    break;
-  case BASEREL:
-    check_textrel();
-    if (!isec.is_relr_reloc(ctx, rel))
-      isec.file.num_dynrel++;
-    break;
-  case IFUNC:
-    dynrel();
-    ctx.num_ifunc_dynrels.fetch_add(1, std::memory_order_relaxed);
-    break;
-  default:
-    unreachable();
-  }
-}
-
-template <typename E>
-static Action get_pcrel_action(Context<E> &ctx, Symbol<E> &sym) {
-  // This is for PC-relative relocations (e.g. R_X86_64_PC32).
-  // We cannot promote them to dynamic relocations because the dynamic
-  // linker generally does not support PC-relative relocations.
-  constexpr static Action table[3][4] = {
-    // Absolute  Local    Imported data  Imported code
-    {  ERROR,    NONE,    ERROR,         PLT    },  // Shared object
-    {  ERROR,    NONE,    COPYREL,       PLT    },  // Position-independent exec
-    {  NONE,     NONE,    COPYREL,       CPLT   },  // Position-dependent exec
-  };
-
-  return get_rel_action(ctx, sym, table);
-}
-
-template <typename E>
-static Action get_absrel_action(Context<E> &ctx, Symbol<E> &sym) {
-  // This is a decision table for absolute relocations that is smaller
-  // than the word size (e.g. R_X86_64_32). Since the dynamic linker
-  // generally does not support dynamic relocations smaller than the
-  // word size, we need to report an error if a relocation cannot be
-  // resolved at link-time.
-  constexpr static Action table[3][4] = {
-    // Absolute  Local    Imported data  Imported code
-    {  NONE,     ERROR,   ERROR,         ERROR },  // Shared object
-    {  NONE,     ERROR,   ERROR,         ERROR },  // Position-independent exec
-    {  NONE,     NONE,    COPYREL,       CPLT  },  // Position-dependent exec
-  };
-
-  return get_rel_action(ctx, sym, table);
-}
-
-template <typename E>
-static Action get_dyn_absrel_action(Context<E> &ctx, Symbol<E> &sym) {
-  if (sym.is_ifunc())
-    return IFUNC;
-
-  // This is a decision table for absolute relocations for the word
-  // size data (e.g. R_X86_64_64). Unlike the absrel_table, we can emit
-  // a dynamic relocation if we cannot resolve an address at link-time.
-  constexpr static Action table[3][4] = {
-    // Absolute  Local    Imported data  Imported code
-    {  NONE,     BASEREL, DYNREL,        DYNREL   },  // Shared object
-    {  NONE,     BASEREL, DYNREL,        DYNREL   },  // Position-independent exec
-    {  NONE,     NONE,    DYN_COPYREL,   DYN_CPLT },  // Position-dependent exec
-  };
-
-  return get_rel_action(ctx, sym, table);
-}
-
-template <typename E>
-static Action get_ppc64_toc_action(Context<E> &ctx, Symbol<E> &sym) {
-  if (sym.is_ifunc())
-    return IFUNC;
-
-  // As a special case, we do not create copy relocations nor canonical
-  // PLTs for .toc sections. PPC64's .toc is a compiler-generated
-  // GOT-like section, and no user-generated code directly uses values
-  // in it.
-  constexpr static Action table[3][4] = {
-    // Absolute  Local    Imported data  Imported code
-    {  NONE,     BASEREL, DYNREL,        DYNREL },  // Shared object
-    {  NONE,     BASEREL, DYNREL,        DYNREL },  // Position-independent exec
-    {  NONE,     NONE,    DYNREL,        DYNREL },  // Position-dependent exec
-  };
-
-  return get_rel_action(ctx, sym, table);
-}
-
-template <typename E>
-void InputSection<E>::scan_pcrel(Context<E> &ctx, Symbol<E> &sym,
-                                 const ElfRel<E> &rel) {
-  scan_rel(ctx, *this, sym, rel, get_pcrel_action(ctx, sym));
-}
-
-template <typename E>
-void InputSection<E>::scan_absrel(Context<E> &ctx, Symbol<E> &sym,
-                                  const ElfRel<E> &rel) {
-  scan_rel(ctx, *this, sym, rel, get_absrel_action(ctx, sym));
-}
-
-template <typename E>
-void InputSection<E>::scan_dyn_absrel(Context<E> &ctx, Symbol<E> &sym,
-                                      const ElfRel<E> &rel) {
-  scan_rel(ctx, *this, sym, rel, get_dyn_absrel_action(ctx, sym));
-}
-
-template <typename E>
-void InputSection<E>::scan_toc_rel(Context<E> &ctx, Symbol<E> &sym,
-                                   const ElfRel<E> &rel) {
-  scan_rel(ctx, *this, sym, rel, get_ppc64_toc_action(ctx, sym));
-}
-
-template <typename E>
-void InputSection<E>::check_tlsle(Context<E> &ctx, Symbol<E> &sym,
-                                  const ElfRel<E> &rel) {
-  if (ctx.arg.shared)
-    Error(ctx) << *this << ": relocation " << rel << " against `" << sym
-               << "` can not be used when making a shared object;"
-               << " recompile with -fPIC";
-}
-
-template <typename E>
-static void apply_absrel(Context<E> &ctx, InputSection<E> &isec,
-                         Symbol<E> &sym, const ElfRel<E> &rel, u8 *loc,
-                         u64 S, i64 A, u64 P, ElfRel<E> *&dynrel,
-                         Action action) {
-  bool writable = (isec.shdr().sh_flags & SHF_WRITE);
-
-  auto apply_dynrel = [&] {
-    *dynrel++ = ElfRel<E>(P, E::R_ABS, sym.get_dynsym_idx(ctx), A);
-    if (ctx.arg.apply_dynamic_relocs)
-      *(Word<E> *)loc = A;
-  };
-
-  switch (action) {
-  case COPYREL:
-  case CPLT:
-  case NONE:
-    *(Word<E> *)loc = S + A;
-    break;
-  case BASEREL:
-    if (isec.is_relr_reloc(ctx, rel)) {
-      *(Word<E> *)loc = S + A;
-    } else {
-      *dynrel++ = ElfRel<E>(P, E::R_RELATIVE, 0, S + A);
-      if (ctx.arg.apply_dynamic_relocs)
-        *(Word<E> *)loc = S + A;
-    }
-    break;
-  case DYN_COPYREL:
-    if (writable || !ctx.arg.z_copyreloc)
-      apply_dynrel();
-    else
-      *(Word<E> *)loc = S + A;
-    break;
-  case DYN_CPLT:
-    if (writable)
-      apply_dynrel();
-    else
-      *(Word<E> *)loc = S + A;
-    break;
-  case DYNREL:
-    apply_dynrel();
-    break;
-  case IFUNC: {
-    if constexpr (supports_ifunc<E>) {
-      u64 addr = sym.get_addr(ctx, NO_PLT) + A;
-      *dynrel++ = ElfRel<E>(P, E::R_IRELATIVE, 0, addr);
-      if (ctx.arg.apply_dynamic_relocs)
-        *(Word<E> *)loc = addr;
-    } else {
-      unreachable();
-    }
-    break;
-  }
-  default:
-    unreachable();
-  }
-}
-
-template <typename E>
-void InputSection<E>::apply_dyn_absrel(Context<E> &ctx, Symbol<E> &sym,
-                                       const ElfRel<E> &rel, u8 *loc,
-                                       u64 S, i64 A, u64 P,
-                                       ElfRel<E> *&dynrel) {
-  apply_absrel(ctx, *this, sym, rel, loc, S, A, P, dynrel,
-               get_dyn_absrel_action(ctx, sym));
-}
-
-template <typename E>
-void InputSection<E>::apply_toc_rel(Context<E> &ctx, Symbol<E> &sym,
-                                    const ElfRel<E> &rel, u8 *loc,
-                                    u64 S, i64 A, u64 P,
-                                    ElfRel<E> *&dynrel) {
-  apply_absrel(ctx, *this, sym, rel, loc, S, A, P, dynrel,
-               get_ppc64_toc_action(ctx, sym));
-}
-
-template <typename E>
-void InputSection<E>::write_to(Context<E> &ctx, u8 *buf) {
-  if (shdr().sh_type == SHT_NOBITS || sh_size == 0)
-    return;
-
-  // Copy data
-  if constexpr (is_riscv<E>) {
-    copy_contents_riscv(ctx, buf);
-  } else {
-    uncompress_to(ctx, buf);
-  }
-
-  // Apply relocations
-  if (!ctx.arg.relocatable) {
-    if (shdr().sh_flags & SHF_ALLOC)
-      apply_reloc_alloc(ctx, buf);
-    else
-      apply_reloc_nonalloc(ctx, buf);
-  }
-}
-
-// Get the name of a function containin a given offset.
-template <typename E>
-std::string_view InputSection<E>::get_func_name(Context<E> &ctx, i64 offset) const {
-  for (const ElfSym<E> &esym : file.elf_syms) {
-    if (esym.st_shndx == shndx && esym.st_type == STT_FUNC &&
-        esym.st_value <= offset && offset < esym.st_value + esym.st_size) {
-      std::string_view name = file.symbol_strtab.data() + esym.st_name;
-      if (ctx.arg.demangle)
-        return demangle(name);
-      return name;
-    }
-  }
-  return "";
-}
-
-// Record an undefined symbol error which will be displayed all at
-// once by report_undef_errors().
-template <typename E>
-void InputSection<E>::record_undef_error(Context<E> &ctx, const ElfRel<E> &rel) {
-  std::stringstream ss;
-  if (std::string_view source = file.get_source_name(); !source.empty())
-    ss << ">>> referenced by " << source << "\n";
-  else
-    ss << ">>> referenced by " << *this << "\n";
-
-  ss << ">>>               " << file;
-  if (std::string_view func = get_func_name(ctx, rel.r_offset); !func.empty())
-    ss << ":(" << func << ")";
-
-  Symbol<E> &sym = *file.symbols[rel.r_sym];
-
-  typename decltype(ctx.undef_errors)::accessor acc;
-  ctx.undef_errors.insert(acc, {sym.name(), {}});
-  acc->second.push_back(ss.str());
-}
-
-using E = MOLD_TARGET;
-
-template struct CieRecord<E>;
-template class InputSection<E>;
-
-} // namespace mold::elf

elf/linker-script.cc

@@ -1,424 +0,0 @@
-// On Linux, /usr/lib/x86_64-linux-gnu/libc.so is not actually
-// a shared object file but an ASCII text file containing a linker
-// script to include a "real" libc.so file. Therefore, we need to
-// support a (very limited) subset of the linker script language.
-
-#include "mold.h"
-
-#include <cctype>
-#include <iomanip>
-
-namespace mold::elf {
-
-template <typename E>
-static thread_local MappedFile<Context<E>> *current_file;
-
-template <typename E>
-void read_version_script(Context<E> &ctx, std::span<std::string_view> &tok);
-
-static std::string_view get_line(std::string_view input, const char *pos) {
-  assert(input.data() <= pos);
-  assert(pos < input.data() + input.size());
-
-  i64 start = input.rfind('\n', pos - input.data());
-  if (start == input.npos)
-    start = 0;
-  else
-    start++;
-
-  i64 end = input.find('\n', pos - input.data());
-  if (end == input.npos)
-    end = input.size();
-
-  return input.substr(start, end - start);
-}
-
-template <typename E>
-class SyntaxError {
-public:
-  SyntaxError(Context<E> &ctx, std::string_view errpos) : out(ctx) {
-    std::string_view contents = current_file<E>->get_contents();
-    std::string_view line = get_line(contents, errpos.data());
-
-    i64 lineno = 1;
-    for (i64 i = 0; contents.data() + i < line.data(); i++)
-      if (contents[i] == '\n')
-        lineno++;
-
-    i64 column = errpos.data() - line.data();
-
-    std::stringstream ss;
-    ss << current_file<E>->name << ":" << lineno << ": ";
-    i64 indent = (i64)ss.tellp() + strlen("mold: ");
-    ss << line << "\n" << std::setw(indent + column) << " " << "^ ";
-    out << ss.str();
-  }
-
-  template <class T> SyntaxError &operator<<(T &&val) {
-    out << std::forward<T>(val);
-    return *this;
-  }
-
-  [[noreturn]] ~SyntaxError() = default;
-
-  Fatal<Context<E>> out;
-};
-
-template <typename E>
-static std::vector<std::string_view>
-tokenize(Context<E> &ctx, std::string_view input) {
-  std::vector<std::string_view> vec;
-  while (!input.empty()) {
-    if (isspace(input[0])) {
-      input = input.substr(1);
-      continue;
-    }
-
-    if (input.starts_with("/*")) {
-      i64 pos = input.find("*/", 2);
-      if (pos == std::string_view::npos)
-        SyntaxError(ctx, input) << "unclosed comment";
-      input = input.substr(pos + 2);
-      continue;
-    }
-
-    if (input[0] == '#') {
-      i64 pos = input.find("\n", 1);
-      if (pos == std::string_view::npos)
-        break;
-      input = input.substr(pos + 1);
-      continue;
-    }
-
-    if (input[0] == '"') {
-      i64 pos = input.find('"', 1);
-      if (pos == std::string_view::npos)
-        SyntaxError(ctx, input) << "unclosed string literal";
-      vec.push_back(input.substr(0, pos + 1));
-      input = input.substr(pos + 1);
-      continue;
-    }
-
-    i64 pos = input.find_first_not_of(
-      "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
-      "0123456789_.$/\\~=+[]*?-!^:");
-
-    if (pos == 0)
-      pos = 1;
-    else if (pos == input.npos)
-      pos = input.size();
-
-    vec.push_back(input.substr(0, pos));
-    input = input.substr(pos);
-  }
-  return vec;
-}
-
-template <typename E>
-static std::span<std::string_view>
-skip(Context<E> &ctx, std::span<std::string_view> tok, std::string_view str) {
-  if (tok.empty())
-    Fatal(ctx) << current_file<E>->name << ": expected '" << str
-               << "', but got EOF";
-  if (tok[0] != str)
-    SyntaxError(ctx, tok[0]) << "expected '" << str << "'";
-  return tok.subspan(1);
-}
-
-static std::string_view unquote(std::string_view s) {
-  if (s.size() > 0 && s[0] == '"') {
-    assert(s[s.size() - 1] == '"');
-    return s.substr(1, s.size() - 2);
-  }
-  return s;
-}
-
-template <typename E>
-static std::span<std::string_view>
-read_output_format(Context<E> &ctx, std::span<std::string_view> tok) {
-  tok = skip(ctx, tok, "(");
-  while (!tok.empty() && tok[0] != ")")
-    tok = tok.subspan(1);
-  if (tok.empty())
-    Fatal(ctx) << current_file<E>->name << ": expected ')', but got EOF";
-  return tok.subspan(1);
-}
-
-template <typename E>
-static bool is_in_sysroot(Context<E> &ctx, std::string path) {
-  std::string rel = to_abs_path(path)
-                        .lexically_relative(to_abs_path(ctx.arg.sysroot))
-                        .string();
-  return rel != "." && !rel.starts_with("../");
-}
-
-template <typename E>
-static MappedFile<Context<E>> *resolve_path(Context<E> &ctx, std::string_view tok) {
-  std::string str(unquote(tok));
-
-  // GNU ld prepends the sysroot if a pathname starts with '/' and the
-  // script being processed is in the sysroot. We do the same.
-  if (str.starts_with('/') && is_in_sysroot(ctx, current_file<E>->name))
-    return MappedFile<Context<E>>::must_open(ctx, ctx.arg.sysroot + str);
-
-  if (str.starts_with('=')) {
-    std::string path;
-    if (ctx.arg.sysroot.empty())
-      path = str.substr(1);
-    else
-      path = ctx.arg.sysroot + str.substr(1);
-    return MappedFile<Context<E>>::must_open(ctx, path);
-  }
-
-  if (str.starts_with("-l"))
-    return find_library(ctx, str.substr(2));
-
-  if (MappedFile<Context<E>> *mf = open_library(ctx, str))
-    return mf;
-
-  for (std::string_view dir : ctx.arg.library_paths) {
-    std::string path = std::string(dir) + "/" + str;
-    if (MappedFile<Context<E>> *mf = open_library(ctx, path))
-      return mf;
-  }
-
-  SyntaxError(ctx, tok) << "library not found: " << str;
-}
-
-template <typename E>
-static std::span<std::string_view>
-read_group(Context<E> &ctx, std::span<std::string_view> tok) {
-  tok = skip(ctx, tok, "(");
-
-  while (!tok.empty() && tok[0] != ")") {
-    if (tok[0] == "AS_NEEDED") {
-      bool orig = ctx.as_needed;
-      ctx.as_needed = true;
-      tok = read_group(ctx, tok.subspan(1));
-      ctx.as_needed = orig;
-      continue;
-    }
-
-    MappedFile<Context<E>> *mf = resolve_path(ctx, tok[0]);
-    read_file(ctx, mf);
-    tok = tok.subspan(1);
-  }
-
-  if (tok.empty())
-    Fatal(ctx) << current_file<E>->name << ": expected ')', but got EOF";
-  return tok.subspan(1);
-}
-
-template <typename E>
-void parse_linker_script(Context<E> &ctx, MappedFile<Context<E>> *mf) {
-  current_file<E> = mf;
-
-  std::vector<std::string_view> vec = tokenize(ctx, mf->get_contents());
-  std::span<std::string_view> tok = vec;
-
-  while (!tok.empty()) {
-    if (tok[0] == "OUTPUT_FORMAT") {
-      tok = read_output_format(ctx, tok.subspan(1));
-    } else if (tok[0] == "INPUT" || tok[0] == "GROUP") {
-      tok = read_group(ctx, tok.subspan(1));
-    } else if (tok[0] == "VERSION") {
-      tok = tok.subspan(1);
-      tok = skip(ctx, tok, "{");
-      read_version_script(ctx, tok);
-      tok = skip(ctx, tok, "}");
-    } else if (tok.size() > 3 && tok[1] == "=" && tok[3] == ";") {
-      ctx.arg.defsyms.emplace_back(get_symbol(ctx, unquote(tok[0])),
-                                   get_symbol(ctx, unquote(tok[2])));
-      tok = tok.subspan(4);
-    } else if (tok[0] == ";") {
-      tok = tok.subspan(1);
-    } else {
-      SyntaxError(ctx, tok[0]) << "unknown linker script token";
-    }
-  }
-}
-
-template <typename E>
-std::string_view
-get_script_output_type(Context<E> &ctx, MappedFile<Context<E>> *mf) {
-  current_file<E> = mf;
-
-  std::vector<std::string_view> vec = tokenize(ctx, mf->get_contents());
-  std::span<std::string_view> tok = vec;
-
-  if (tok.size() >= 3 && tok[0] == "OUTPUT_FORMAT" && tok[1] == "(") {
-    if (tok[2] == "elf64-x86-64")
-      return X86_64::target_name;
-    if (tok[2] == "elf32-i386")
-      return I386::target_name;
-  }
-
-  if (tok.size() >= 3 && (tok[0] == "INPUT" || tok[0] == "GROUP") &&
-      tok[1] == "(")
-    if (MappedFile<Context<E>> *mf =
-        MappedFile<Context<E>>::open(ctx, std::string(unquote(tok[2]))))
-      return get_machine_type(ctx, mf);
-
-  return "";
-}
-
-static bool read_label(std::span<std::string_view> &tok,
-                       std::string label) {
-  if (tok.size() >= 1 && tok[0] == label + ":") {
-    tok = tok.subspan(1);
-    return true;
-  }
-
-  if (tok.size() >= 2 && tok[0] == label && tok[1] == ":") {
-    tok = tok.subspan(2);
-    return true;
-  }
-  return false;
-}
-
-template <typename E>
-static void
-read_version_script_commands(Context<E> &ctx, std::span<std::string_view> &tok,
-                             std::string_view ver_str, u16 ver_idx, bool is_cpp) {
-  bool is_global = true;
-
-  while (!tok.empty() && tok[0] != "}") {
-    if (read_label(tok, "global")) {
-      is_global = true;
-      continue;
-    }
-
-    if (read_label(tok, "local")) {
-      is_global = false;
-      continue;
-    }
-
-    if (tok[0] == "extern") {
-      tok = tok.subspan(1);
-
-      if (!tok.empty() && tok[0] == "\"C\"") {
-        tok = tok.subspan(1);
-        tok = skip(ctx, tok, "{");
-        read_version_script_commands( ctx, tok, ver_str, ver_idx, false);
-      } else {
-        tok = skip(ctx, tok, "\"C++\"");
-        tok = skip(ctx, tok, "{");
-        read_version_script_commands(ctx, tok, ver_str, ver_idx, true);
-      }
-
-      tok = skip(ctx, tok, "}");
-      tok = skip(ctx, tok, ";");
-      continue;
-    }
-
-    if (tok[0] == "*") {
-      ctx.default_version = (is_global ? ver_idx : (u32)VER_NDX_LOCAL);
-      ctx.default_version_from_version_script = true;
-    } else if (is_global) {
-      ctx.version_patterns.push_back({unquote(tok[0]), current_file<E>->name,
-                                      ver_str, ver_idx, is_cpp});
-    } else {
-      ctx.version_patterns.push_back({unquote(tok[0]), current_file<E>->name,
-                                      ver_str, VER_NDX_LOCAL, is_cpp});
-    }
-
-    tok = tok.subspan(1);
-
-    if (!tok.empty() && tok[0] == "}")
-      return;
-    tok = skip(ctx, tok, ";");
-  }
-}
-
-template <typename E>
-void read_version_script(Context<E> &ctx, std::span<std::string_view> &tok) {
-  u16 next_ver = VER_NDX_LAST_RESERVED + ctx.arg.version_definitions.size() + 1;
-
-  while (!tok.empty() && tok[0] != "}") {
-    std::string_view ver_str;
-    u16 ver_idx;
-
-    if (tok[0] == "{") {
-      ver_str = "global";
-      ver_idx = VER_NDX_GLOBAL;
-    } else {
-      ver_str = tok[0];
-      ver_idx = next_ver++;
-      ctx.arg.version_definitions.push_back(std::string(tok[0]));
-      tok = tok.subspan(1);
-    }
-
-    tok = skip(ctx, tok, "{");
-    read_version_script_commands(ctx, tok, ver_str, ver_idx, false);
-    tok = skip(ctx, tok, "}");
-    if (!tok.empty() && tok[0] != ";")
-      tok = tok.subspan(1);
-    tok = skip(ctx, tok, ";");
-  }
-}
-
-template <typename E>
-void parse_version_script(Context<E> &ctx, MappedFile<Context<E>> *mf) {
-  current_file<E> = mf;
-  std::vector<std::string_view> vec = tokenize(ctx, mf->get_contents());
-  std::span<std::string_view> tok = vec;
-  read_version_script(ctx, tok);
-  if (!tok.empty())
-    SyntaxError(ctx, tok[0]) << "trailing garbage token";
-}
-
-template <typename E>
-void read_dynamic_list_commands(Context<E> &ctx, std::span<std::string_view> &tok,
-                                bool is_cpp) {
-  while (!tok.empty() && tok[0] != "}") {
-    if (tok[0] == "extern") {
-      tok = tok.subspan(1);
-
-      if (!tok.empty() && tok[0] == "\"C\"") {
-        tok = tok.subspan(1);
-        tok = skip(ctx, tok, "{");
-        read_dynamic_list_commands(ctx, tok, false);
-      } else {
-        tok = skip(ctx, tok, "\"C++\"");
-        tok = skip(ctx, tok, "{");
-        read_dynamic_list_commands(ctx, tok, true);
-      }
-
-      tok = skip(ctx, tok, "}");
-      tok = skip(ctx, tok, ";");
-      continue;
-    }
-
-    if (tok[0] == "*")
-      ctx.default_version = VER_NDX_GLOBAL;
-    else
-      ctx.version_patterns.push_back({unquote(tok[0]), current_file<E>->name,
-                                      "global", VER_NDX_GLOBAL, is_cpp});
-
-    tok = skip(ctx, tok.subspan(1), ";");
-  }
-}
-
-template <typename E>
-void parse_dynamic_list(Context<E> &ctx, MappedFile<Context<E>> *mf) {
-  current_file<E> = mf;
-  std::vector<std::string_view> vec = tokenize(ctx, mf->get_contents());
-  std::span<std::string_view> tok = vec;
-
-  tok = skip(ctx, tok, "{");
-  read_dynamic_list_commands(ctx, tok, false);
-  tok = skip(ctx, tok, "}");
-  tok = skip(ctx, tok, ";");
-
-  if (!tok.empty())
-    SyntaxError(ctx, tok[0]) << "trailing garbage token";
-}
-
-using E = MOLD_TARGET;
-
-template void parse_linker_script(Context<E> &, MappedFile<Context<E>> *);
-template std::string_view get_script_output_type(Context<E> &, MappedFile<Context<E>> *);
-template void parse_version_script(Context<E> &, MappedFile<Context<E>> *);
-template void parse_dynamic_list(Context<E> &, MappedFile<Context<E>> *);
-
-} // namespace mold::elf

elf/lto.cc

@@ -1,5 +0,0 @@
-#ifdef _WIN32
-# include "lto-win32.cc"
-#else
-# include "lto-unix.cc"
-#endif

elf/thunks.cc

@@ -1,296 +0,0 @@
-// RISC instructions are usually up to 4 bytes long, so the immediates of
-// their branch instructions are naturally smaller than 32 bits.  This is
-// contrary to x86-64 on which branch instructions take 4 bytes immediates
-// and can jump to anywhere within PC ± 2 GiB.
-//
-// In fact, ARM32's branch instructions can jump only within ±16 MiB and
-// ARM64's ±128 MiB, for example. If a branch target is further than that,
-// we need to let it branch to a linker-synthesized code sequence that
-// construct a full 32 bit address in a register and jump there. That
-// linker-synthesized code is called "thunk".
-//
-// The function in this file creates thunks.
-//
-// Note that although thunks play an important role in an executable, they
-// don't take up too much space in it. For example, among the clang-16's
-// text segment whose size is ~300 MiB on ARM64, thunks in total occupy
-// only ~30 KiB or 0.01%. Of course the number depends on an ISA; we would
-// need more thunks on ARM32 whose branch range is shorter than ARM64.
-// That said, the total size of thunks still isn't that much. Therefore,
-// we don't need to try too hard to reduce thunk size to the absolute
-// minimum.
-
-#include "mold.h"
-
-#include <tbb/parallel_for.h>
-#include <tbb/parallel_for_each.h>
-
-namespace mold::elf {
-
-// Returns a branch reach in bytes for a given target.
-template <typename E>
-static consteval i64 max_distance() {
-  // ARM64's branch has 26 bits immediate. The immediate is padded with
-  // implicit two-bit zeros because all instructions are 4 bytes aligned
-  // and therefore the least two bits are always zero. So the branch
-  // operand is effectively 28 bits long. That means the branch range is
-  // [-2^27, 2^27) or PC ± 128 MiB.
-  if (is_arm64<E>)
-    return 1 << 27;
-
-  // ARM32's Thumb branch has 24 bits immediate, and the instructions are
-  // aligned to 2, so it's effectively 25 bits. It's [-2^24, 2^24) or PC ±
-  // 16 MiB.
-  //
-  // ARM32's non-Thumb branches have twice longer range than its Thumb
-  // counterparts, but we conservatively use the Thumb's limitation.
-  if (is_arm32<E>)
-    return 1 << 24;
-
-  // PPC's branch has 24 bits immediate, and the instructions are aligned
-  // to 4, therefore the reach is [-2^25, 2^25) or PC ± 32 MiB.
-  assert(is_ppc<E>);
-  return 1 << 25;
-}
-
-// We create thunks for each 12.8/1.6/3.2 MiB code block for
-// ARM64/ARM32/PPC, respectively.
-template <typename E>
-static constexpr i64 batch_size = max_distance<E>() / 10;
-
-// We assume that a single thunk group is smaller than 100 KiB.
-static constexpr i64 max_thunk_size = 102400;
-
-// Returns true if a given relocation is of type used for function calls.
-template <typename E>
-static bool needs_thunk_rel(const ElfRel<E> &r) {
-  u32 ty = r.r_type;
-
-  if constexpr (is_arm64<E>) {
-    return ty == R_AARCH64_JUMP26 || ty == R_AARCH64_CALL26;
-  } else if constexpr (is_arm32<E>) {
-    return ty == R_ARM_JUMP24 || ty == R_ARM_THM_JUMP24 ||
-           ty == R_ARM_CALL   || ty == R_ARM_THM_CALL;
-  } else if constexpr (is_ppc32<E>) {
-    return ty == R_PPC_REL24  || ty == R_PPC_PLTREL24 || ty == R_PPC_LOCAL24PC;
-  } else {
-    static_assert(is_ppc64<E>);
-    return ty == R_PPC64_REL24;
-  }
-}
-
-template <typename E>
-static bool is_reachable(Context<E> &ctx, InputSection<E> &isec,
-                         Symbol<E> &sym, const ElfRel<E> &rel) {
-  // We create thunks with a pessimistic assumption that all
-  // out-of-section relocations would be out-of-range.
-  InputSection<E> *isec2 = sym.get_input_section();
-  if (!isec2 || isec.output_section != isec2->output_section)
-    return false;
-
-  // Even if the target is the same section, we branch to its PLT
-  // if it has one. So a symbol with a PLT is also considered an
-  // out-of-section reference.
-  if (sym.has_plt(ctx))
-    return false;
-
-  // If the target section is in the same output section but
-  // hasn't got any address yet, that's unreacahble.
-  if (isec2->offset == -1)
-    return false;
-
-  // Thumb and ARM B instructions cannot be converted to BX, so we
-  // always have to make them jump to a thunk to switch processor mode
-  // even if their destinations are within their ranges.
-  if constexpr (is_arm32<E>) {
-    bool is_thumb = sym.get_addr(ctx) & 1;
-    if ((rel.r_type == R_ARM_THM_JUMP24 && !is_thumb) ||
-        (rel.r_type == R_ARM_JUMP24 && is_thumb))
-      return false;
-  }
-
-  // Compute a distance between the relocated place and the symbol
-  // and check if they are within reach.
-  i64 S = sym.get_addr(ctx, NO_OPD);
-  i64 A = get_addend(isec, rel);
-  i64 P = isec.get_addr() + rel.r_offset;
-  i64 val = S + A - P;
-  return -max_distance<E>() <= val && val < max_distance<E>();
-}
-
-template <typename E>
-static void reset_thunk(RangeExtensionThunk<E> &thunk) {
-  for (Symbol<E> *sym : thunk.symbols) {
-    sym->extra.thunk_idx = -1;
-    sym->extra.thunk_sym_idx = -1;
-    sym->flags = 0;
-  }
-}
-
-// Scan relocations to collect symbols that need thunks.
-template <typename E>
-static void scan_rels(Context<E> &ctx, InputSection<E> &isec,
-                      RangeExtensionThunk<E> &thunk, i64 thunk_idx) {
-  std::span<const ElfRel<E>> rels = isec.get_rels(ctx);
-  std::vector<RangeExtensionRef> &range_extn = isec.extra.range_extn;
-  range_extn.resize(rels.size());
-
-  for (i64 i = 0; i < rels.size(); i++) {
-    const ElfRel<E> &rel = rels[i];
-    if (!needs_thunk_rel(rel))
-      continue;
-
-    // Skip if the symbol is undefined. apply_reloc() will report an error.
-    Symbol<E> &sym = *isec.file.symbols[rel.r_sym];
-    if (!sym.file)
-      continue;
-
-    // Skip if the destination is within reach.
-    if (is_reachable(ctx, isec, sym, rel))
-      continue;
-
-    // This relocation needs a thunk. If the symbol is already in a
-    // previous thunk, reuse it.
-    if (sym.extra.thunk_idx != -1) {
-      range_extn[i].thunk_idx = sym.extra.thunk_idx;
-      range_extn[i].sym_idx = sym.extra.thunk_sym_idx;
-      continue;
-    }
-
-    // Otherwise, add the symbol to the current thunk if it's not
-    // added already.
-    range_extn[i].thunk_idx = thunk_idx;
-    range_extn[i].sym_idx = -1;
-
-    if (sym.flags.exchange(-1) == 0) {
-      std::scoped_lock lock(thunk.mu);
-      thunk.symbols.push_back(&sym);
-    }
-  }
-}
-
-template <typename E>
-void create_range_extension_thunks(Context<E> &ctx, OutputSection<E> &osec) {
-  std::span<InputSection<E> *> m = osec.members;
-  if (m.empty())
-    return;
-
-  m[0]->offset = 0;
-
-  // Initialize input sections with a dummy offset so that we can
-  // distinguish sections that have got an address with the one who
-  // haven't.
-  tbb::parallel_for((i64)1, (i64)m.size(), [&](i64 i) {
-    m[i]->offset = -1;
-  });
-
-  // We create thunks from the beginning of the section to the end.
-  // We manage progress using four offsets which increase monotonically.
-  // The locations they point to are always A <= B <= C <= D.
-  //
-  //  ................................ <input sections> ............
-  //     A    B    C    D
-  //                   ^
-  //                   We insert a thunk for the current batch just before D
-  //          <--->      The current batch, which is smaller than batch_size
-  //     <-------->      smaller than max_distance
-  //          <--------> Smaller than max_distance
-  //     <-------------> Reachable from the current batch
-  //
-  // A is the input section with the smallest address than can reach
-  // anywhere from the current batch.
-  //
-  // D is the input section with the largest address such that the thunk
-  // is reachable from the current batch if it's inserted right before D
-  // but at least partially unreacahble if it's inserted after D.
-  i64 a = 0;
-  i64 b = 0;
-  i64 c = 0;
-  i64 d = 0;
-  i64 offset = 0;
-
-  while (b < m.size()) {
-    // Move D foward as far as we can jump from B to anywhere in a thunk after D.
-    while (d < m.size() &&
-           align_to(offset, 1 << m[d]->p2align) + m[d]->sh_size + max_thunk_size <
-           m[b]->offset + max_distance<E>()) {
-      offset = align_to(offset, 1 << m[d]->p2align);
-      m[d]->offset = offset;
-      offset += m[d]->sh_size;
-      d++;
-    }
-
-    // Move C forward so that C is apart from B by BATCH_SIZE. We want
-    // to make sure that there's at least one section between B and C
-    // to ensure progress.
-    c = b + 1;
-    while (c < m.size() &&
-           m[c]->offset + m[c]->sh_size < m[b]->offset + batch_size<E>)
-      c++;
-
-    // Move A forward so that A is reachable from C.
-    i64 c_offset = (c == m.size()) ? offset : m[c]->offset;
-    while (a < osec.thunks.size() &&
-           osec.thunks[a]->offset + max_distance<E>() < c_offset)
-      reset_thunk(*osec.thunks[a++]);
-
-    // Create a thunk for input sections between B and C and place it at D.
-    offset = align_to(offset, RangeExtensionThunk<E>::alignment);
-    RangeExtensionThunk<E> *thunk = new RangeExtensionThunk<E>(osec, offset);
-    i64 thunk_idx = osec.thunks.size();
-    osec.thunks.emplace_back(thunk);
-
-    // Scan relocations between B and C to collect symbols that need thunks.
-    tbb::parallel_for_each(m.begin() + b, m.begin() + c,
-                           [&](InputSection<E> *isec) {
-      scan_rels(ctx, *isec, *thunk, thunk_idx);
-    });
-
-    // Now that we know the number of symbols in the thunk, we can compute
-    // its size.
-    assert(thunk->size() < max_thunk_size);
-    offset += thunk->size();
-
-    // Sort symbols added to the thunk to make the output deterministic.
-    sort(thunk->symbols, [](Symbol<E> *a, Symbol<E> *b) {
-      return std::tuple{a->file->priority, a->sym_idx} <
-             std::tuple{b->file->priority, b->sym_idx};
-    });
-
-    // Assign offsets within the thunk to the symbols.
-    for (i64 i = 0; Symbol<E> *sym : thunk->symbols) {
-      sym->extra.thunk_idx = thunk_idx;
-      sym->extra.thunk_sym_idx = i++;
-    }
-
-    // Scan relocations again to fix symbol offsets in the last thunk.
-    tbb::parallel_for_each(m.begin() + b, m.begin() + c,
-                           [&](InputSection<E> *isec) {
-      std::span<Symbol<E> *> syms = isec->file.symbols;
-      std::span<const ElfRel<E>> rels = isec->get_rels(ctx);
-      std::span<RangeExtensionRef> range_extn = isec->extra.range_extn;
-
-      for (i64 i = 0; i < rels.size(); i++)
-        if (range_extn[i].thunk_idx == thunk_idx)
-          range_extn[i].sym_idx = syms[rels[i].r_sym]->extra.thunk_sym_idx;
-    });
-
-    // Move B forward to point to the begining of the next batch.
-    b = c;
-  }
-
-  while (a < osec.thunks.size())
-    reset_thunk(*osec.thunks[a++]);
-
-  osec.shdr.sh_size = offset;
-}
-
-#if MOLD_ARM32 || MOLD_ARM64 || MOLD_PPC32 || MOLD_PPC64V1 || MOLD_PPC64V2
-using E = MOLD_TARGET;
-
-static_assert(max_thunk_size / E::thunk_size < INT16_MAX);
-
-template void create_range_extension_thunks(Context<E> &, OutputSection<E> &);
-#endif
-
-} // namespace mold::elf

elf/tls.cc

@@ -1,212 +0,0 @@
-// This file contains helper functions for thread-local storage (TLS).
-// TLS is probably the most obscure feature the linker has to support,
-// so I'll explain it in detail in this comment.
-//
-// TLS is a per-thread storage. Thread-local variables (TLVs) are in a TLS
-// so that each thread has its own set of thread-local variables. Taking
-// an address of a TLV returns a unique value for each thread. For example,
-// `&foo` for the following code returns different pointer values for
-// different threads.
-//
-//   thread_local int foo;
-//
-// TLV is a relatively new feature. C for example didn't provide the
-// official support for it through the keyword `thread_local` until C11.
-// TLV needs a coordination between the compiler, the linker and the
-// runtime to work correctly.
-//
-// An ELF exectuable or a shared library using TLV contains a "TLS
-// template image" in the PT_TLS segment. For each newly created thread
-// including the initial one, the runtime allocates a contiguous memory
-// for TLS template images for an executable and its depending shared
-// libraries and copies template images there. That per-thread memory is
-// called the "TLS block". After allocating and initializing a TLS block,
-// the runtime sets a register to refer to the TLS block, so that the
-// thread-local variables are accessible relative to the register.
-//
-// The register referring the per-thread storage is called the Thread
-// Pointer (TP). TP is part of the thread's context. When the kernel
-// scheduler switches threads, TP is saved and restored automatically just
-// like other registers are.
-//
-// The TLS template image is read-only. It contains TLVs' initial values
-// for new threads, and no one writes to it at runtime.
-//
-// Now, let's think about how to access a TLV. We need to know the TLV's
-// address to access it which can be done in various ways as follows:
-//
-//  1. If we are creating an executable, we know the exact size of the TLS
-//     template image we are creating, and we know where the TP will be
-//     set to after the template is copied to the TLS block. Therefore,
-//     the TP-relative address of a TLV in the main executable is known at
-//     link-time. That means, computing a TLV's address can be as easy as
-//     `add %dst, %tp, <link-time constant>`.
-//
-//  2. If we are creating a shared library, we don't exactly know where
-//     its TLS template image will be copied to in terms of the
-//     TP-relative address, because we don't know how large is the main
-//     executable's and other libraries' TLS template images are. Only the
-//     runtime knows the exact TP-relative address.
-//
-//     We can solve the problem with an indirection. Specifically, for
-//     each TLV whose TP-relative address is only known at process startup
-//     time, we create a GOT entry to store its TP-relative address. We
-//     also emit a dynamic relocation to let the runtime to fill the GOT
-//     entry with a per-TLV TP-relative address.
-//
-//     Computing a TLV address in this scheme needs at least two machine
-//     instructions; first one loads a value from a GOT entry, and the
-//     second adds the loaded value to TP.
-//
-//  3. Now, think about libraries that you dynamically load with dlopen.
-//     Even the runtime doesn't know how many bytes has to be reserved for
-//     such libraries, so TLVs in dlopen'ed libraries cannot be allocated
-//     in the initial TLS block.
-//
-//     The address of such TLV is obtained by calling a libc-provided
-//     function, __tls_get_addr(). The function takes two arguments; a
-//     module ID to identify the ELF file and the TLV's offset within the
-//     ELF file's TLS template image. Accessing a TLV is sometimes
-//     compiled to a function call! The module ID and the offset are
-//     usually stored to GOT as two consecutive words.
-//
-// The last access method is the most generic, so the compiler emits such
-// code by default. But that's the most expensive one, so the linker
-// rewrites instructions if possible so that 3) is relaxed to 2) or even
-// to 1).
-//
-// 1) is often called the Local Exec access model. 2) is Initial Exec, and
-// 3) is called General Dynamic.
-//
-// There's also a trick that the compiler can use if it knows two TLVs are
-// in the same ELF file (usually in the same file as the code is). In this
-// case, we can call __tls_get_addr() only once with a module ID and the
-// offset 0 to obtain the base address of the ELF file's TLS block.
-// The base address obtained this way is sometimes called Dynamic Thread
-// Pointer or DTP. We can then compute TLVs' addresses by adding their
-// DTP-relative addresses to DTP. This access model is called the Local
-// Dynamic.
-//
-//
-// === TLS Descriptor access model ===
-//
-// As described above, there are arguably too many different TLS access
-// models from the most generic one you can use in any ELF file to the
-// most efficient one you can use only in the main executable. Compiling
-// source code with an appropriate TLS access model is bothersome.
-// To solve the problem, a new TLS access model was proposed. That is
-// called the TLS Descriptor (TLSDESC) model.
-//
-// For a TLV compiled with TLSDESC, we allocate two consecutive GOT slots
-// and create a TLSDESC dynamic relocation for them. The dynamic linker
-// sets a function pointer to the first GOT slot and its argument to the
-// second slot.
-//
-// To access the TLV, we call the function pointer with the argument we
-// read from the second GOT slot. The function returns the TLV's
-// TP-relative address.
-//
-// The runtime chooses the best access method depending on the situation
-// and sets a pointer to the most efficient code to the first GOT slot.
-// For example, if a TLV's TP-relative address is known at process startup
-// time, the runtime sets that address to the second GOT slot and set a
-// function that just returns its argument to the first GOT slot.
-//
-// With TLSDECS, the compiler can always emit the same code for TLVs
-// without sacrificing runtime performance.
-//
-// TLSDESC is better than the traditional, non-TLSDESC TLS access models.
-// It's the default on ARM64, but on other targets, TLSDESC is
-// unfortunately either optional or even not supported at all. So we still
-// need to support both the traditional TLS models and the TLSDESC model.
-
-#include "mold.h"
-
-namespace mold::elf {
-
-template <typename E>
-static ElfPhdr<E> *get_tls_segment(Context<E> &ctx) {
-  if (ctx.phdr)
-    for (ElfPhdr<E> &phdr : ctx.phdr->phdrs)
-      if (phdr.p_type == PT_TLS)
-        return &phdr;
-  return nullptr;
-}
-
-template <typename E>
-u64 get_tls_begin(Context<E> &ctx) {
-  if (ElfPhdr<E> *phdr = get_tls_segment(ctx))
-    return phdr->p_vaddr;
-  return 0;
-}
-
-// Returns the TP address which can be used for efficient TLV accesses in
-// the main executable. TP at runtime refers to a per-process TLS block
-// whose address is not known at link-time. So the address returned from
-// this function is the TP if the TLS template image were a TLS block.
-template <typename E>
-u64 get_tp_addr(Context<E> &ctx) {
-  ElfPhdr<E> *phdr = get_tls_segment(ctx);
-  if (!phdr)
-    return 0;
-
-  // On x86, SPARC and s390x, TP (%gs on i386, %fs on x86-64, %g7 on SPARC
-  // and %a0/%a1 on s390x) refers past the end of the TLS block for
-  // historical reasons. TLVs are accessed with negative offsets from TP.
-  if constexpr (is_x86<E> || is_sparc<E> || is_s390x<E>)
-    return align_to(phdr->p_vaddr + phdr->p_memsz, phdr->p_align);
-
-  // On ARM, SH4 and Alpha, the runtime appends two words at the beginning
-  // of TLV template image when copying TLVs to the TLS block, so we need
-  // to offset it.
-  if constexpr (is_arm<E> || is_sh4<E> || is_alpha<E>)
-    return align_down(phdr->p_vaddr - sizeof(Word<E>) * 2, phdr->p_align);
-
-  // On PPC and m68k, TP is 0x7000 (28 KiB) past the beginning of the TLV
-  // block to maximize the addressable range for load/store instructions
-  // with 16-bits signed immediates. It's not exactly 0x8000 (32 KiB) off
-  // because there's a small implementation-defined piece of data before
-  // the TLV block, and the runtime wants to access them efficiently too.
-  if constexpr (is_ppc<E> || is_m68k<E>)
-    return phdr->p_vaddr + 0x7000;
-
-  // RISC-V just uses the beginning of the main executable's TLV block as
-  // TP. RISC-V load/store instructions usually take 12-bits signed
-  // immediates, so the beginning of TLV ± 2 KiB is accessible with a
-  // single load/store instruction.
-  assert(is_riscv<E>);
-  return phdr->p_vaddr;
-}
-
-// Returns the address when __tls_get_addr would be called with offset 0.
-template <typename E>
-u64 get_dtp_addr(Context<E> &ctx) {
-  ElfPhdr<E> *phdr = get_tls_segment(ctx);
-  if (!phdr)
-    return 0;
-
-  // On PPC64 and m68k, R_DTPOFF is resolved to the address 0x8000 (32
-  // KiB) past the start of the TLS block. The bias maximizes the
-  // accessible range for load/store instructions with 16-bits signed
-  // immediates. That is, if the offset were right at the beginning of
-  // the start of the TLS block, the half of addressible space (negative
-  // immediates) would have been wasted.
-  if constexpr (is_ppc<E> || is_m68k<E>)
-    return phdr->p_vaddr + 0x8000;
-
-  // On RISC-V, the bias is 0x800 as the load/store instructions in the
-  // ISA usually have a 12-bit immediate.
-  if constexpr (is_riscv<E>)
-    return phdr->p_vaddr + 0x800;
-
-  // On other targets, DTP simply refers to the beginning of the TLS block.
-  return phdr->p_vaddr;
-}
-
-using E = MOLD_TARGET;
-
-template u64 get_tls_begin<E>(Context<E> &);
-template u64 get_tp_addr<E>(Context<E> &);
-template u64 get_dtp_addr<E>(Context<E> &);
-
-} // namespace mold::elf

install-build-deps.sh

@@ -1,49 +1,54 @@
 #!/bin/sh
+# This script installs binary packages needed to build mold.
+# Feel free to send me a PR if your OS is not on this list.
+
 set -e
 . /etc/os-release
 
 set -x
 
-# The first line for each distro installs a build dependency.
-# The second line installs extra packages for unittests.
-#
-# Feel free to send me a PR if your OS is not on this list.
-
-case "$ID-$VERSION_ID" in
-ubuntu-20.* | pop-20.*)
+case "$ID" in
+ubuntu | pop | linuxmint | debian | raspbian | neon | zorin)
   apt-get update
-  apt-get install -y cmake libssl-dev zlib1g-dev gcc g++ g++-10
-  apt-get install -y file
+  apt-get install -y cmake gcc g++ clang gdb
   ;;
-ubuntu-* | pop-* | linuxmint-* | debian-* | raspbian-*)
-  apt-get update
-  apt-get install -y cmake libssl-dev zlib1g-dev gcc g++
-  apt-get install -y file
+fedora | fedora-* | amzn | rhel | centos)
+  dnf install -y gcc-c++ cmake glibc-static libstdc++-static diffutils util-linux tar
   ;;
-fedora-*)
-  dnf install -y gcc-g++ cmake openssl-devel zlib-devel
-  dnf install -y glibc-static file libstdc++-static diffutils util-linux
+rocky | ol)
+  dnf install -y gcc-c++ cmake diffutils util-linux
   ;;
-opensuse-leap-*)
-  zypper install -y make cmake zlib-devel libopenssl-devel gcc-c++ gcc11-c++
-  zypper install -y glibc-devel-static tar diffutils util-linux
+opensuse-*)
+  zypper install -y make cmake gcc-c++ glibc-devel-static tar diffutils util-linux gawk
   ;;
-opensuse-tumbleweed-*)
-  zypper install -y make cmake zlib-devel libopenssl-devel gcc-c++
-  zypper install -y glibc-devel-static tar diffutils util-linux
-  ;;
-gentoo-*)
+gentoo)
   emerge-webrsync
-  emerge dev-util/cmake sys-libs/zlib
+  FEATURES='getbinpkg binpkg-request-signature' emerge dev-build/cmake
   ;;
-arch-*)
-  pacman -Sy
-  pacman -S --needed --noconfirm base-devel zlib openssl cmake util-linux
+arch | archarm | artix | endeavouros | manjaro | cachyos)
+  pacman -Sy --needed --noconfirm base-devel cmake util-linux
   ;;
-void-*)
-  xbps-install -Sy xbps
-  xbps-install -Sy bash make cmake openssl-devel zlib-devel gcc
-  xbps-install -Sy tar diffutils util-linux
+void)
+  xbps-install -Sy xbps bash make cmake gcc tar diffutils util-linux
+  ;;
+alpine)
+  apk update
+  apk add bash make linux-headers cmake gcc g++
+  ;;
+clear-linux-os)
+  swupd update
+  swupd bundle-add c-basic diffutils
+  ;;
+almalinux)
+  dnf install -y gcc-toolset-13-gcc-c++ gcc-toolset-13-libstdc++-devel cmake diffutils
+  ;;
+altlinux)
+  apt-get update
+  apt-get install -y gcc-c++ make cmake ctest diffutils util-linux
+  ;;
+freebsd)
+  pkg update
+  pkg install -y cmake bash binutils gcc
   ;;
 *)
   echo "Error: don't know anything about build dependencies on $ID-$VERSION_ID"

install-cross-tools.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+set -e
+. /etc/os-release
+
+set -x
+
+# This script install packages for -DMOLD_ENABLE_QEMU_TESTS=1
+# to enable cross-target tests.
+#
+# Feel free to send me a PR if your OS is not on this list.
+
+case "$ID" in
+ubuntu | pop | linuxmint | debian | raspbian)
+  apt-get install -y qemu-user {gcc,g++}-{i686,aarch64,riscv64,powerpc,powerpc64,powerpc64le,s390x,sparc64,m68k,sh4}-linux-gnu {gcc,g++}-arm-linux-gnueabihf
+  ;;
+*)
+  echo "Error: don't know anything about build dependencies on $ID-$VERSION_ID"
+  exit 1
+esac

lib/aho-corasick.cc

@@ -0,0 +1,132 @@
+// This file implements the Aho-Corasick algorithm to search multiple
+// strings within an input string simultaneously. It is essentially a
+// trie with additional links. For details, see
+// https://en.wikipedia.org/wiki/Aho-Corasick_algorithm.
+//
+// We use it for simple glob patterns in version scripts or dynamic
+// list files. Here are some examples of glob patterns:
+//
+//    qt_private_api_tag*
+//    *16QAccessibleCache*
+//    *32QAbstractFileIconProviderPrivate*
+//    *17QPixmapIconEngine*
+//
+// Aho-Corasick can do only substring search, so it cannot handle
+// complex glob patterns such as `*foo*bar*`. We handle such patterns
+// with the Glob class.
+
+#include "lib.h"
+
+#include <queue>
+
+namespace mold {
+
+bool AhoCorasick::can_handle(std::string_view pat) {
+  if (pat.starts_with('*'))
+    pat.remove_prefix(1);
+  if (pat.ends_with('*'))
+    pat.remove_suffix(1);
+  return pat.find_first_of("*?[") == pat.npos;
+}
+
+i64 AhoCorasick::find(std::string_view str) {
+  if (nodes.empty())
+    return -1;
+
+  i64 idx = 0;
+  i64 val = -1;
+
+  auto walk = [&](u8 c) {
+    for (i64 j = idx; j != -1; j = nodes[j].suffix_link) {
+      i64 child = nodes[j].children[c];
+      if (child != -1) {
+        idx = child;
+        val = std::max(val, nodes[child].value);
+        return;
+      }
+    }
+    idx = 0;
+  };
+
+  walk('\0');
+  for (u8 c : str)
+    walk(c);
+  walk('\0');
+  return val;
+}
+
+bool AhoCorasick::add(std::string_view pat, i64 val) {
+  assert(can_handle(pat));
+  if (nodes.empty())
+    nodes.resize(1);
+  i64 idx = 0;
+
+  auto walk = [&](u8 c) {
+    if (nodes[idx].children[c] == -1) {
+      nodes[idx].children[c] = nodes.size();
+      nodes.resize(nodes.size() + 1);
+    }
+    idx = nodes[idx].children[c];
+  };
+
+  // We handle "foo" as if "\0foo\0", "*foo" as if "foo\0", "foo*" as
+  // if "\0foo", and "*foo*" as if "foo". Aho-Corasick can do only
+  // substring matching, so we use \0 as a beginning/end-of-string
+  // markers.
+  if (!pat.starts_with('*'))
+    walk('\0');
+  for (u8 c : pat)
+    if (c != '*')
+      walk(c);
+  if (!pat.ends_with('*'))
+    walk('\0');
+
+  nodes[idx].value = std::max(nodes[idx].value, val);
+  return true;
+}
+
+void AhoCorasick::compile() {
+  if (nodes.empty())
+    return;
+  fix_suffix_links(0);
+  fix_values();
+}
+
+void AhoCorasick::fix_suffix_links(i64 idx) {
+  for (i64 i = 0; i < 256; i++) {
+    i64 child = nodes[idx].children[i];
+    if (child == -1)
+      continue;
+
+    i64 j = nodes[idx].suffix_link;
+    for (; j != -1; j = nodes[j].suffix_link) {
+      if (nodes[j].children[i] != -1) {
+        nodes[child].suffix_link = j;
+        break;
+      }
+    }
+    if (j == -1)
+      nodes[child].suffix_link = 0;
+    fix_suffix_links(child);
+  }
+}
+
+void AhoCorasick::fix_values() {
+  std::queue<i64> queue;
+  queue.push(0);
+
+  do {
+    i64 idx = queue.front();
+    queue.pop();
+
+    for (i64 child : nodes[idx].children) {
+      if (child != -1) {
+        i64 suffix = nodes[child].suffix_link;
+        nodes[child].value = std::max(nodes[child].value, nodes[suffix].value);
+        queue.push(child);
+      }
+    }
+  } while (!queue.empty());
+}
+
+} // namespace mold

lib/atomics.h

@@ -0,0 +1,50 @@
+// This is the same as std::atomic except that the default memory
+// order is relaxed instead of sequential consistency.
+
+#pragma once
+
+#include <atomic>
+
+namespace mold {
+
+template <typename T>
+struct Atomic : std::atomic<T> {
+  static constexpr std::memory_order relaxed = std::memory_order_relaxed;
+
+  using std::atomic<T>::atomic;
+
+  Atomic(const Atomic<T> &other) : std::atomic<T>(other.load()) {}
+
+  Atomic<T> &operator=(const Atomic<T> &other) {
+    store(other.load());
+    return *this;
+  }
+
+  void operator=(T val) { store(val); }
+  operator T() const { return load(); }
+
+  void store(T val, std::memory_order order = relaxed) {
+    std::atomic<T>::store(val, order);
+  }
+
+  T load(std::memory_order order = relaxed) const {
+    return std::atomic<T>::load(order);
+  }
+
+  T exchange(T val) { return std::atomic<T>::exchange(val, relaxed); }
+  T operator|=(T val) { return std::atomic<T>::fetch_or(val, relaxed); }
+  T operator++() { return std::atomic<T>::fetch_add(1, relaxed) + 1; }
+  T operator--() { return std::atomic<T>::fetch_sub(1, relaxed) - 1; }
+  T operator++(int) { return std::atomic<T>::fetch_add(1, relaxed); }
+  T operator--(int) { return std::atomic<T>::fetch_sub(1, relaxed); }
+
+  bool test_and_set() {
+    // A relaxed load + branch (assuming miss) takes only around 20 cycles,
+    // while an atomic RMW can easily take hundreds on x86. We note that it's
+    // common that another thread beat us in marking, so doing an optimistic
+    // early test tends to improve performance in the ~20% ballpark.
+    return load() || exchange(true);
+  }
+};
+
+} // namespace mold

lib/bitvector.h

@@ -0,0 +1,78 @@
+#pragma once
+
+#include "integers.h"
+
+#include <cassert>
+#include <vector>
+
+namespace mold {
+
+class BitvectorProxy {
+public:
+  BitvectorProxy(u64 &word, size_t pos)
+    : word(word), mask(1ULL << pos) {}
+
+  BitvectorProxy &operator=(bool val) {
+    if (val)
+      word |= mask;
+    else
+      word &= ~mask;
+    return *this;
+  }
+
+  BitvectorProxy &operator=(const BitvectorProxy &other) {
+    return *this = (bool)other;
+  }
+
+  operator bool() const {
+    return word & mask;
+  }
+
+private:
+  u64 &word;
+  u64 mask;
+};
+
+class Bitvector {
+public:
+  Bitvector() = default;
+  Bitvector(i64 n) : size(n), words((n + 63) / 64) {}
+
+  void resize(i64 n) {
+    words.clear();
+    words.resize((n + 63) / 64);
+    size = n;
+  }
+
+  Bitvector &operator|=(const Bitvector &x) {
+    assert(size == x.size);
+    for (i64 i = 0; i < words.size(); i++)
+      words[i] |= x.words[i];
+    return *this;
+  }
+
+  Bitvector &operator&=(const Bitvector &x) {
+    assert(size == x.size);
+    for (i64 i = 0; i < words.size(); i++)
+      words[i] &= x.words[i];
+    return *this;
+  }
+
+  Bitvector &operator<<=(size_t n) {
+    assert(n == 1);
+    for (i64 i = words.size() - 1; i > 0; i--)
+      words[i] = (words[i] << 1) | (words[i - 1] >> 63);
+    words[0] <<= 1;
+    return *this;
+  }
+
+  BitvectorProxy operator[](size_t pos) {
+    assert(pos < size);
+    return {words[pos / 64], pos % 64};
+  }
+
+  i64 size = 0;
+  std::vector<u64> words;
+};
+
+} // namespace mold

lib/compress.cc

@@ -14,7 +14,7 @@
 // a little bit. However, if a shard size is large enough, that loss
 // is negligible in practice.
 
-#include "common.h"
+#include "lib.h"
 
 #include <tbb/parallel_for_each.h>
 #include <zlib.h>
@@ -30,42 +30,41 @@ namespace mold {
 
 static constexpr i64 SHARD_SIZE = 1024 * 1024;
 
-static std::vector<std::string_view> split(std::string_view input) {
-  std::vector<std::string_view> shards;
-
-  while (input.size() >= SHARD_SIZE) {
-    shards.push_back(input.substr(0, SHARD_SIZE));
-    input = input.substr(SHARD_SIZE);
-  }
-  if (!input.empty())
-    shards.push_back(input);
-  return shards;
+Compressor::~Compressor() {
+  for (std::span<u8> shard : shards)
+    delete[] shard.data();
 }
 
-static std::vector<u8> zlib_compress(std::string_view input) {
-  // Initialize zlib stream. Since debug info is generally compressed
-  // pretty well with lower compression levels, we chose compression
-  // level 1.
-  z_stream strm;
-  strm.zalloc = Z_NULL;
-  strm.zfree = Z_NULL;
-  strm.opaque = Z_NULL;
+static std::vector<std::span<u8>> split(std::span<u8> input) {
+  std::vector<std::span<u8>> vec;
+  while (!input.empty()) {
+    i64 sz = std::min<i64>(SHARD_SIZE, input.size());
+    vec.push_back(input.subspan(0, sz));
+    input = input.subspan(sz);
+  }
+  return vec;
+}
 
-  CHECK(deflateInit2(&strm, 1, Z_DEFLATED, -15, 8, Z_DEFAULT_STRATEGY));
+static std::span<u8> zlib_compress(std::span<u8> input, int level) {
+  // Initialize zlib stream. Since debug info is generally compressed
+  // pretty well with lower compression levels, the default level is 1.
+  z_stream strm = {};
+  CHECK(deflateInit2(&strm, level, Z_DEFLATED, -15, 8, Z_DEFAULT_STRATEGY));
 
   // Set an input buffer
   strm.avail_in = input.size();
-  strm.next_in = (u8 *)input.data();
+  strm.next_in = input.data();
 
   // Set an output buffer. deflateBound() returns an upper bound
   // on the compression size. +16 for Z_SYNC_FLUSH.
-  std::vector<u8> buf(deflateBound(&strm, strm.avail_in) + 16);
+  i64 bufsize = deflateBound(&strm, strm.avail_in) + 16;
+  u8 *buf = new u8[bufsize];
 
   // Compress data. It writes all compressed bytes except the last
   // partial byte, so up to 7 bits can be held to be written to the
   // buffer.
-  strm.avail_out = buf.size();
-  strm.next_out = buf.data();
+  strm.avail_out = bufsize;
+  strm.next_out = buf;
   CHECK(deflate(&strm, Z_BLOCK));
 
   // This is a workaround for libbacktrace before 2022-04-06.
@@ -84,29 +83,26 @@ static std::vector<u8> zlib_compress(std::string_view input) {
   // that the bit position is 7 in the next byte.
   //
   // https://github.com/ianlancetaylor/libbacktrace/pull/87
-  int nbits;
+  int nbits = 0;
   deflatePending(&strm, Z_NULL, &nbits);
   if (nbits == 5)
     CHECK(deflatePrime(&strm, 10, 2));
   CHECK(deflate(&strm, Z_SYNC_FLUSH));
 
-  assert(strm.avail_out > 0);
-  buf.resize(buf.size() - strm.avail_out);
-  buf.shrink_to_fit();
   deflateEnd(&strm);
-  return buf;
+  return {buf, (size_t)(bufsize - strm.avail_out)};
 }
 
-ZlibCompressor::ZlibCompressor(u8 *buf, i64 size) {
-  std::string_view input{(char *)buf, (size_t)size};
-  std::vector<std::string_view> inputs = split(input);
-  std::vector<u64> adlers(inputs.size());
+ZlibCompressor::ZlibCompressor(u8 *buf, i64 size, i64 level) {
+  std::vector<std::span<u8>> inputs = split(std::span(buf, size));
+  std::vector<u32> adlers(inputs.size());
   shards.resize(inputs.size());
 
   // Compress each shard
   tbb::parallel_for((i64)0, (i64)inputs.size(), [&](i64 i) {
-    adlers[i] = adler32(1, (u8 *)inputs[i].data(), inputs[i].size());
-    shards[i] = zlib_compress(inputs[i]);
+    std::span<u8> in = inputs[i];
+    adlers[i] = adler32(1, in.data(), in.size());
+    shards[i] = zlib_compress(in, level);
   });
 
   // Combine checksums
@@ -116,7 +112,7 @@ ZlibCompressor::ZlibCompressor(u8 *buf, i64 size) {
 
   // Comput the total size
   compressed_size = 8; // the header and the trailer
-  for (std::vector<u8> &shard : shards)
+  for (std::span<u8> &shard : shards)
     compressed_size += shard.size();
 }
 
@@ -127,47 +123,40 @@ void ZlibCompressor::write_to(u8 *buf) {
 
   // Copy compressed data
   std::vector<i64> offsets(shards.size());
-  offsets[0] = 2; // +2 for header
+  offsets[0] = 2; // +2 for the header
   for (i64 i = 1; i < shards.size(); i++)
     offsets[i] = offsets[i - 1] + shards[i - 1].size();
 
   tbb::parallel_for((i64)0, (i64)shards.size(), [&](i64 i) {
-    memcpy(&buf[offsets[i]], shards[i].data(), shards[i].size());
+    memcpy(buf + offsets[i], shards[i].data(), shards[i].size());
   });
 
   // Write a trailer
   u8 *end = buf + compressed_size;
   end[-6] = 3;
   end[-5] = 0;
-
-  // Write a checksum
   *(ub32 *)(end - 4) = checksum;
 }
 
-static std::vector<u8> zstd_compress(std::string_view input) {
-  std::vector<u8> buf(ZSTD_COMPRESSBOUND(input.size()));
-  constexpr int level = 3; // compression level; must be between 1 to 22
-
-  size_t sz = ZSTD_compress(buf.data(), buf.size(), input.data(), input.size(),
-                            level);
+static std::span<u8> zstd_compress(std::span<u8> input, int level) {
+  i64 bufsize = ZSTD_COMPRESSBOUND(input.size());
+  u8 *buf = new u8[bufsize];
+  size_t sz = ZSTD_compress(buf, bufsize, input.data(), input.size(), level);
   assert(!ZSTD_isError(sz));
-  buf.resize(sz);
-  buf.shrink_to_fit();
-  return buf;
+  return {buf, sz};
 }
 
-ZstdCompressor::ZstdCompressor(u8 *buf, i64 size) {
-  std::string_view input{(char *)buf, (size_t)size};
-  std::vector<std::string_view> inputs = split(input);
+ZstdCompressor::ZstdCompressor(u8 *buf, i64 size, i64 level) {
+  std::vector<std::span<u8>> inputs = split(std::span(buf, size));
   shards.resize(inputs.size());
 
   // Compress each shard
   tbb::parallel_for((i64)0, (i64)inputs.size(), [&](i64 i) {
-    shards[i] = zstd_compress(inputs[i]);
+    shards[i] = zstd_compress(inputs[i], level);
   });
 
   compressed_size = 0;
-  for (std::vector<u8> &shard : shards)
+  for (std::span<u8> &shard : shards)
     compressed_size += shard.size();
 }
 
@@ -178,7 +167,7 @@ void ZstdCompressor::write_to(u8 *buf) {
     offsets[i] = offsets[i - 1] + shards[i - 1].size();
 
   tbb::parallel_for((i64)0, (i64)shards.size(), [&](i64 i) {
-    memcpy(&buf[offsets[i]], shards[i].data(), shards[i].size());
+    memcpy(buf + offsets[i], shards[i].data(), shards[i].size());
   });
 }
 

lib/config.h.in

@@ -0,0 +1,29 @@
+#define MOLD_VERSION "@mold_VERSION@"
+#define MOLD_LIBDIR "@CMAKE_INSTALL_FULL_LIBDIR@"
+#define MOLD_FIRST_TARGET @MOLD_FIRST_TARGET@
+
+#cmakedefine01 HAVE_MADVISE
+#cmakedefine01 HAVE_UNAME
+#cmakedefine01 MOLD_USE_MIMALLOC
+#cmakedefine01 MOLD_USE_SYSTEM_MIMALLOC
+
+#cmakedefine01 HAVE_TARGET_X86_64
+#cmakedefine01 HAVE_TARGET_I386
+#cmakedefine01 HAVE_TARGET_ARM64LE
+#cmakedefine01 HAVE_TARGET_ARM64BE
+#cmakedefine01 HAVE_TARGET_ARM32LE
+#cmakedefine01 HAVE_TARGET_ARM32BE
+#cmakedefine01 HAVE_TARGET_RV32LE
+#cmakedefine01 HAVE_TARGET_RV32BE
+#cmakedefine01 HAVE_TARGET_RV64LE
+#cmakedefine01 HAVE_TARGET_RV64BE
+#cmakedefine01 HAVE_TARGET_PPC32
+#cmakedefine01 HAVE_TARGET_PPC64V1
+#cmakedefine01 HAVE_TARGET_PPC64V2
+#cmakedefine01 HAVE_TARGET_S390X
+#cmakedefine01 HAVE_TARGET_SPARC64
+#cmakedefine01 HAVE_TARGET_M68K
+#cmakedefine01 HAVE_TARGET_SH4LE
+#cmakedefine01 HAVE_TARGET_SH4BE
+#cmakedefine01 HAVE_TARGET_LOONGARCH64
+#cmakedefine01 HAVE_TARGET_LOONGARCH32

lib/crc32.cc

@@ -0,0 +1,60 @@
+#include "lib.h"
+
+#include <tbb/parallel_for_each.h>
+#include <zlib.h>
+
+namespace mold {
+
+// This function "forges" a CRC. That is, given the current and a desired
+// CRC32 value, crc32_solve() returns a binary blob to add to the end of
+// the original data to yield the desired CRC. Trailing garbage is ignored
+// by many bianry file formats, so you can create a file with a desired
+// CRC using crc32_solve(). We need it for --separate-debug-file.
+std::vector<u8> crc32_solve(u32 current, u32 desired) {
+  constexpr u32 poly = 0xedb88320;
+  u32 x = ~desired;
+
+  // Each iteration computes x = (x * x^-1) mod poly.
+  for (i64 i = 0; i < 32; i++) {
+    x = std::rotl(x, 1);
+    x ^= (x & 1) * (poly << 1);
+  }
+
+  x ^= ~current;
+
+  std::vector<u8> out(4);
+  out[0] = x;
+  out[1] = x >> 8;
+  out[2] = x >> 16;
+  out[3] = x >> 24;
+  return out;
+}
+
+// Compute a CRC for given data in parallel
+u32 compute_crc32(u32 crc, u8 *buf, i64 len) {
+  struct Shard {
+    u8 *buf;
+    i64 len;
+    u32 crc;
+  };
+
+  constexpr i64 shard_size = 1024 * 1024; // 1 MiB
+  std::vector<Shard> shards;
+
+  while (len > 0) {
+    i64 sz = std::min(len, shard_size);
+    shards.push_back({buf, sz, 0});
+    buf += sz;
+    len -= sz;
+  }
+
+  tbb::parallel_for_each(shards, [](Shard &shard) {
+    shard.crc = crc32(0, shard.buf, shard.len);
+  });
+
+  for (Shard &shard : shards)
+    crc = crc32_combine(crc, shard.crc, shard.len);
+  return crc;
+}
+
+} // namespace mold

lib/demangle.cc

@@ -1,4 +1,4 @@
-#include "common.h"
+#include "lib.h"
 
 #include <cstdlib>
 
@@ -10,25 +10,7 @@
 
 namespace mold {
 
-std::string_view demangle(std::string_view name) {
-  static thread_local char *p;
-  if (p)
-    free(p);
-
-  // Try to demangle as a Rust symbol. Since legacy-style Rust symbols
-  // are also valid as a C++ mangled name, we need to call this before
-  // cpp_demangle.
-  p = rust_demangle(std::string(name).c_str(), 0);
-  if (p)
-    return p;
-
-  // Try to demangle as a C++ symbol.
-  if (std::optional<std::string_view> s = cpp_demangle(name))
-    return *s;
-  return name;
-}
-
-std::optional<std::string_view> cpp_demangle(std::string_view name) {
+std::optional<std::string_view> demangle_cpp(std::string_view name) {
   static thread_local char *buf;
   static thread_local size_t buflen;
 
@@ -48,4 +30,13 @@ std::optional<std::string_view> cpp_demangle(std::string_view name) {
   return {};
 }
 
+std::optional<std::string_view> demangle_rust(std::string_view name) {
+  static thread_local char *buf;
+  free(buf);
+  buf = rust_demangle(std::string(name).c_str(), 0);
+  if (buf)
+    return buf;
+  return {};
+}
+
 } // namespace mold

lib/filepath.cc

@@ -0,0 +1,42 @@
+#include "lib.h"
+
+#include <filesystem>
+#include <sys/stat.h>
+
+#ifdef __APPLE__
+# include <mach-o/dyld.h>
+#endif
+
+#ifdef __FreeBSD__
+# include <sys/sysctl.h>
+#endif
+
+namespace mold {
+
+// Returns the path of the mold executable itself
+std::string get_self_path() {
+#if __APPLE__ || _WIN32
+  fprintf(stderr, "mold: get_self_path is not supported");
+  exit(1);
+#elif __FreeBSD__
+  // /proc may not be mounted on FreeBSD. The proper way to get the
+  // current executable's path is to use sysctl(2).
+  int mib[4];
+  mib[0] = CTL_KERN;
+  mib[1] = KERN_PROC;
+  mib[2] = KERN_PROC_PATHNAME;
+  mib[3] = -1;
+
+  size_t size;
+  sysctl(mib, 4, NULL, &size, NULL, 0);
+
+  std::string path;
+  path.resize(size);
+  sysctl(mib, 4, path.data(), &size, NULL, 0);
+  return path;
+#else
+  return std::filesystem::read_symlink("/proc/self/exe").string();
+#endif
+}
+
+} // namespace mold

lib/gentoo-test.sh

@@ -1,14 +1,14 @@
 #!/bin/bash
 #
 # This test script takes a Gentoo package name and tries to build it
-# using mold in a Docker environment. We chose Gentoo Linux as a test
+# using mold in a Podman environment. We chose Gentoo Linux as a test
 # target, because its source-based package allows us to build programs
 # locally and run their test suites without any hassle.
 #
 # You can get a complete list of Gentoo packages availalbe for testing
 # with the following command:
 #
-# docker run --rm mold-gentoo emerge --color n -s '' | \
+# podman run --rm mold-gentoo emerge --color n -s '' | \
 #   perl -ne 'next unless m!^\*\s+(\S+/\S+)!; print "$1\n"'
 
 package="$1"
@@ -20,47 +20,48 @@ fi
 
 set -x
 
-# Create a Docker image
-if ! docker image ls mold-gentoo | grep -q mold-gentoo; then
+# Create a Podman image
+if ! podman image ls mold-gentoo | grep -q mold-gentoo; then
   set -e
-  cat <<EOF | docker build -t mold-gentoo -
-FROM gentoo/stage3
+  cat <<EOF | podman build -t mold-gentoo -
+FROM docker.io/gentoo/stage3
 RUN emerge-webrsync
-RUN echo 'USE="X ssl elogind -systemd corefonts truetype jpeg jpeg2k tiff zstd static-libs binary"' >> /etc/portage/make.conf && \
+RUN echo 'USE="X ssl elogind -systemd corefonts truetype jpeg jpeg2k tiff zstd static-libs binary -perl"' >> /etc/portage/make.conf && \
     echo 'ACCEPT_KEYWORDS="~amd64"' >> /etc/portage/make.conf && \
     echo 'ACCEPT_LICENSE="* -@EULA"' >> /etc/portage/make.conf && \
     echo 'FEATURES="\${FEATURE} noclean nostrip ccache -ipc-sandbox -network-sandbox -pid-sandbox -sandbox"' >> /etc/portage/make.conf && \
-    echo 'CCACHE_DIR="/ccache"' >> /etc/portage/make.conf
-RUN emerge gdb lld clang vim emacs strace ccache xeyes dev-util/cmake dev-vcs/git && rm -rf /var/tmp/portage
+    echo 'CCACHE_DIR="/ccache"' >> /etc/portage/make.conf && \
+    FEATURES='getbinpkg binpkg-request-signature' emerge gdb lld llvm-core/clang vim emacs strace ccache xeyes dev-build/cmake dev-vcs/git && \
+    rm -rf /var/tmp/portage
 EOF
   set +e
 fi
 
-git_hash=$(./mold --version | perl -ne '/\((\w+)/; print $1;')
+git_hash=$(./dist/mold --version | perl -ne '/\((\w+)/; print $1;')
 
 if [ "$package" = dev-libs/concurrencykit ]; then
   echo "Skipping known broken package: $package"
   exit 0
 fi
 
-# Build a given package in Docker
-cmd1='(cd /usr/bin; ln -sf /mold/mold $(realpath ld))'
+# Build a given package in Podman
+cmd1='(cd /usr/bin; ln -sf /mold/dist/mold $(realpath ld))'
 cmd2="MAKEOPTS=-'j$(nproc) --load-average=100' emerge --onlydeps $package"
 cmd3="MAKEOPTS='-j$(nproc) --load-average=100' FEATURES=test emerge $package"
 filename=`echo "$package" | sed 's!/!_!g'`
-docker="docker run --rm --cap-add=SYS_PTRACE -v `pwd`:/mold -v /var/cache/ccache-gentoo:/ccache mold-gentoo timeout -v -k 15s 1h"
+podman="podman run --rm --pids-limit=-1 --cap-add=SYS_PTRACE -v `pwd`:/mold:ro -v /var/cache/ccache-gentoo:/ccache mold-gentoo timeout -v -k 15s 3h"
 dir=gentoo/$git_hash
 
 mkdir -p "$dir"/success "$dir"/failure
 
-$docker nice -n 19 bash -c "$cmd1 && $cmd2 && $cmd3" >& "$dir"/"$filename".mold
+$podman chrt --idle 0 nice -n 19 bash -c "$cmd1 && $cmd2 && $cmd3" >& "$dir"/"$filename".mold
 if [ $? = 0 ]; then
   mv "$dir"/"$filename".mold "$dir"/success
 else
   mv "$dir"/"$filename".mold "$dir"/failure
 fi
 
-$docker nice -n 19 bash -c "$cmd2 && $cmd3" >& "$dir"/"$filename".ld
+$podman chrt --idle 0 nice -n 19 bash -c "$cmd2 && $cmd3" >& "$dir"/"$filename".ld
 if [ $? = 0 ]; then
   mv "$dir"/"$filename".ld "$dir"/success
 else

lib/glob.cc

@@ -0,0 +1,256 @@
+// This file implements a glob matcher that can run multiple glob patterns
+// against an input string. mold uses the glob matcher for symbol name
+// patterns in a version script or a dynamic list file. Since we may need to
+// match hundreds of glob patterns against millions of symbol names, the
+// speed of the matcher is very important.
+//
+// The pattern match implemented in this file is NFA-based, although the
+// cost of the function is O(n*m), where n is the number of NFA states and m
+// is the length of the input string. We do not use recursion or
+// backtracking, unlike a generic NFA-based regular expression matcher. This
+// is doable because glob patterns are very limited subsets of regexes.
+//
+// Here is the explanation of the algorithm. Observe that the only "tricky"
+// meta-character in a glob pattern is "*", which matches zero or more
+// characters. Other characters and meta-characters always match a single
+// input character. So the key of the algorithm is to handle "*" efficiently.
+//
+// We can represent a glob pattern "a*b*" with three NFA states: q_start, q1
+// and q_accept, with the following transition functions:
+//
+//   δ(q_start, "a") = q1
+//   δ(q1, <any character>) = q1
+//   δ(q1, "b") = q_accept
+//   δ(q_accept, <any character>) = q_accept
+//
+// We can construct such an NFA in a straightforward manner. We maintain NFA
+// states as a list, with the initial contents being the start state. Each
+// character except for "*" creates a new NFA state, adds a transition from
+// the last state in the list to the new one, and appends the new state at
+// the end of the list. "*" sets the "is_star" flag on the last NFA state.
+// The flag indicates that the state machine can remain in the state for any
+// input character.
+//
+// An NFA constructed this way doesn't have any complicated loops,
+// ε-transitions, or anything like that. Each state has only one incoming
+// edge. The only loops in the state transition are the self-loops on states
+// followed by a "*". Aside from that, the state machine progresses linearly
+// from the start state to the accept state.
+//
+// Each state of an NFA can be represented by a single bit. If a bit is 1,
+// the non-deterministic state machine is in that state. Otherwise, it's
+// not. Observe that a state with the "is_star" flag will continued to be 1
+// once it becomes 1, since the state machine can loop over the state on any
+// input character.
+//
+// With that observation, we can represent an NFA with a bit vector of N
+// bits, where N is the number of NFA states. For each input character, bit
+// M becomes 1 if
+//
+//   - bit M-1 is 1 and there's a transition from state_{M-1} to state_M
+//     with the given character, or
+//   - bit M is 1 and state_M's "is_star" flag is 1.
+//
+// Initially, the 0th bit is 1 for the start state. At each step, the bits
+// propagate from least significant to most significant positions, at most
+// one bit at a time. If the most significant bit is 1 after the entire
+// input has been processed, the string matches.
+//
+// This propagation can be implemented with bitwise OR, bitwise AND, and a
+// one-bit bit shift on the bit vector. All these operations are very cheap.
+//
+// We can combine multiple glob matchers into a single matcher by simply
+// concatenating the bit vectors of their state machines.
+
+#include "lib.h"
+
+#include <cstring>
+
+namespace mold {
+
+static std::vector<MultiGlob::State> parse_glob(std::string_view pat) {
+  std::vector<MultiGlob::State> vec(1);
+
+  while (!pat.empty()) {
+    u8 c = pat[0];
+    pat = pat.substr(1);
+    std::bitset<256> chars;
+
+    switch (c) {
+    case '*':
+      vec.back().is_star = true;
+      continue;
+    case '?':
+      chars.set();
+      break;
+    case '\\':
+      if (pat.empty())
+        return {};
+      chars[pat[0]] = true;
+      pat = pat.substr(1);
+      break;
+    case '[': {
+      // Here are a few bracket pattern examples:
+      //
+      // [abc]: a, b or c
+      // [$\]!]: $, ] or !
+      // [a-czg-i]: a, b, c, z, g, h, or i
+      // [!a-z]: Any character except lowercase letters
+      //
+      // Both `!` and `^` are accepted as negation markers. `!` is the
+      // POSIX/shell convention used by other linkers. `^` was mold's
+      // original syntax and is kept for backward compatibility.
+      bool negate = false;
+      bool closed = false;
+
+      if (!pat.empty() && (pat[0] == '!' || pat[0] == '^')) {
+        negate = true;
+        pat = pat.substr(1);
+      }
+
+      while (!pat.empty()) {
+        if (pat[0] == ']') {
+          pat = pat.substr(1);
+          closed = true;
+          break;
+        }
+
+        if (pat[0] == '\\') {
+          pat = pat.substr(1);
+          if (pat.empty())
+            return {};
+        }
+
+        if (pat.size() >= 3 && pat[1] == '-') {
+          u8 start = pat[0];
+          u8 end = pat[2];
+          pat = pat.substr(3);
+
+          if (end == '\\') {
+            if (pat.empty())
+              return {};
+            end = pat[0];
+            pat = pat.substr(1);
+          }
+
+          if (end < start)
+            return {};
+
+          for (i64 i = start; i <= end; i++)
+            chars[i] = true;
+        } else {
+          chars[pat[0]] = true;
+          pat = pat.substr(1);
+        }
+      }
+
+      if (!closed)
+        return {};
+
+      if (negate)
+        chars.flip();
+      break;
+    }
+    default:
+      chars[c] = true;
+      break;
+    }
+
+    vec.push_back({chars, false});
+  }
+  return vec;
+}
+
+// Instead of returning just a match/no match boolean value, our glob
+// matcher returns an integer value associated with each given pattern.
+// If multiple patterns match at the same time, the largest associated
+// value will be returned by find().
+bool MultiGlob::add(std::string_view pat, i64 val) {
+  std::vector<State> vec = parse_glob(pat);
+  if (vec.empty())
+    return false;
+  patterns.push_back({std::move(vec), val});
+  return true;
+}
+
+void MultiGlob::compile() {
+  if (patterns.empty())
+    return;
+
+  ranges::stable_sort(patterns, ranges::greater(), &GlobPattern::value);
+
+  std::vector<State> states;
+  for (GlobPattern &p : patterns)
+    append(states, p.states);
+  i64 sz = states.size();
+
+  start_states.resize(sz);
+  for (i64 pos = 0; GlobPattern &p : patterns) {
+    start_states[pos] = true;
+    pos += p.states.size();
+  }
+
+  star_mask.resize(sz);
+  for (i64 i = 0; i < sz; i++)
+    if (states[i].is_star)
+      star_mask[i] = true;
+
+  for (i64 i = 0; i < 256; i++) {
+    char_mask[i].resize(sz);
+    for (i64 j = 0; j < sz; j++)
+      if (states[j].incoming_edge[i])
+        char_mask[i][j] = true;
+  }
+}
+
+i64 MultiGlob::find(std::string_view str) {
+  if (patterns.empty())
+    return -1;
+
+  Bitvector bits = start_states;
+  Bitvector tmp;
+
+  for (u8 c : str) {
+    // This is equivalent to
+    //
+    //   bits = (bits & star_mask) | ((bits << 1) & char_mask[c])
+    //
+    // but we update the existing objects in place to avoid allocating
+    // temporary objects.
+    tmp = bits;
+    tmp &= star_mask;
+    bits <<= 1;
+    bits &= char_mask[c];
+    bits |= tmp;
+  }
+
+  for (i64 pos = 0; GlobPattern &p : patterns) {
+    pos += p.states.size();
+    if (bits[pos - 1])
+      return p.value;
+  }
+  return -1;
+}
+
+bool Glob::add(std::string_view pat, i64 val) {
+  assert(val >= 0);
+  assert(!is_compiled);
+
+  // If the pattern requires only a single substring search, the
+  // Aho-Corasick algorithm is even faster than our glob matcher.
+  if (aho_corasick.can_handle(pat))
+    return aho_corasick.add(pat, val);
+  return multi_glob.add(pat, val);
+}
+
+i64 Glob::find(std::string_view str) {
+  std::call_once(once, [&] {
+    multi_glob.compile();
+    aho_corasick.compile();
+    is_compiled = true;
+  });
+
+  return std::max(multi_glob.find(str), aho_corasick.find(str));
+}
+
+} // namespace mold

lib/hyperloglog.cc

@@ -4,7 +4,7 @@
 // For more info, read
 // https://engineering.fb.com/2018/12/13/data-infrastructure/hyperloglog
 
-#include "common.h"
+#include "lib.h"
 
 #include <cmath>
 
@@ -13,7 +13,7 @@ namespace mold {
 i64 HyperLogLog::get_cardinality() const {
   double z = 0;
   for (i64 val : buckets)
-    z += pow(2, -val);
+    z += std::ldexp(1.0, -val);
   return ALPHA * NBUCKETS * NBUCKETS / z;
 }
 

lib/integers.h

@@ -0,0 +1,127 @@
+// This file defines integral types for file input/output. We need to use
+// these types instead of the plain integers (such as uint32_t or int32_t)
+// when reading from/writing to an mmap'ed file area for the following
+// reasons:
+//
+// 1. mold is always a cross linker and should not depend on what host it
+//    is running on. For example, users should be able to run mold on a
+//    little-endian x86 machine to create a big-endian s390x binary.
+//
+// 2. Even though data members in all ELF data strucutres are naturally
+//    aligned, they are not guaranteed to be aligned on memory because of
+//    archive files. Archive files (.a files) align each file only to a
+//    2 byte boundary, so anything larger than 2 bytes may be misaligned
+//    in an mmap'ed memory. Misaligned access is an undefined behavior in
+//    C/C++, so we shouldn't cast an arbitrary pointer to a uint32_t, for
+//    example, to read a 32 bit value.
+//
+// The data types defined in this file are independent of the host byte
+// order and are designed to avoid unaligned access.
+//
+// Note that in C/C++, memcpy is a portable and efficient way to access
+// unaligned data, as it is typically treated as an intrinsic. Compilers
+// can easily optimize memcpy calls in this file into a single load or
+// store instruction.
+
+#pragma once
+
+#include <bit>
+#include <cstdint>
+#include <cstring>
+#include <type_traits>
+
+#if !defined(__LITTLE_ENDIAN__) && !defined(__BIG_ENDIAN__)
+# if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#  define __LITTLE_ENDIAN__ 1
+# elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#  define __BIG_ENDIAN__ 1
+# else
+#  error "unknown host byte order"
+# endif
+#endif
+
+namespace mold {
+
+template <typename T, bool is_le, int size = sizeof(T)>
+class Integer {
+public:
+  constexpr Integer() = default;
+
+  constexpr Integer(T v) {
+    if (std::is_constant_evaluated() || size == 3) {
+      for (int i = 0; i < size; i++)
+        buf[is_le ? i : (size - i - 1)] = v >> (i * 8);
+    } else {
+      if (!is_native)
+        v = bswap(v);
+      memcpy(buf, &v, size);
+    }
+  }
+
+  operator T() const {
+    if (size == 3) {
+      if (is_le)
+        return buf[2] << 16 | buf[1] << 8 | buf[0];
+      return buf[0] << 16 | buf[1] << 8 | buf[2];
+    }
+
+    T v;
+    memcpy(&v, buf, size);
+    return is_native ? v : bswap(v);
+  }
+
+  Integer &operator=(T v)  { new (this) Integer(v); return *this; }
+  Integer &operator++()    { return *this = *this + 1; }
+  Integer operator++(int)  { auto x = *this; ++*this; return x; }
+  Integer &operator--()    { return *this = *this - 1; }
+  Integer operator--(int)  { auto x = *this; --*this; return x; }
+  Integer &operator+=(T v) { return *this = *this + v; }
+  Integer &operator-=(T v) { return *this = *this - v; }
+  Integer &operator&=(T v) { return *this = *this & v; }
+  Integer &operator|=(T v) { return *this = *this | v; }
+
+private:
+  static constexpr bool is_native =
+    (std::endian::native == (is_le ? std::endian::little : std::endian::big));
+
+  static T bswap(T v) {
+    switch (size) {
+    case 2: return __builtin_bswap16(v);
+    case 4: return __builtin_bswap32(v);
+    case 8: return __builtin_bswap64(v);
+    default: __builtin_unreachable();
+    }
+  }
+
+  uint8_t buf[size];
+};
+
+using i8 = int8_t;
+using i16 = int16_t;
+using i32 = int32_t;
+using i64 = int64_t;
+
+using u8 = uint8_t;
+using u16 = uint16_t;
+using u32 = uint32_t;
+using u64 = uint64_t;
+
+using il16 = Integer<i16, true>;
+using il32 = Integer<i32, true>;
+using il64 = Integer<i64, true>;
+
+using ul16 = Integer<u16, true>;
+using ul24 = Integer<u32, true, 3>;
+using ul32 = Integer<u32, true>;
+using ul64 = Integer<u64, true>;
+
+using ib16 = Integer<i16, false>;
+using ib32 = Integer<i32, false>;
+using ib64 = Integer<i64, false>;
+
+using ub16 = Integer<u16, false>;
+using ub24 = Integer<u32, false, 3>;
+using ub32 = Integer<u32, false>;
+using ub64 = Integer<u64, false>;
+
+} // namespace mold

lib/lib.h

@@ -0,0 +1,709 @@
+#pragma once
+
+#include "atomics.h"
+#include "integers.h"
+#include "bitvector.h"
+
+#include <array>
+#include <atomic>
+#include <bit>
+#include <bitset>
+#include <cassert>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <fcntl.h>
+#include <filesystem>
+#include <iostream>
+#include <mutex>
+#include <optional>
+#include <span>
+#include <sstream>
+#include <string>
+#include <string_view>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <tbb/concurrent_vector.h>
+#include <tbb/enumerable_thread_specific.h>
+#include <tbb/parallel_for.h>
+#include <vector>
+
+#ifdef _WIN32
+# include <io.h>
+#else
+# include <sys/mman.h>
+# include <unistd.h>
+#endif
+
+#define XXH_INLINE_ALL 1
+#include "../third-party/xxhash/xxhash.h"
+
+#ifdef NDEBUG
+# define unreachable() __builtin_unreachable()
+#else
+# define unreachable() assert(0 && "unreachable")
+#endif
+
+inline uint64_t hash_string(std::string_view str) {
+  return XXH3_64bits(str.data(), str.size());
+}
+
+class HashCmp {
+public:
+  static size_t hash(const std::string_view &k) {
+    return hash_string(k);
+  }
+
+  static bool equal(const std::string_view &k1, const std::string_view &k2) {
+    return k1 == k2;
+  }
+};
+
+namespace mold {
+
+namespace ranges = std::ranges;
+using namespace std::literals::string_literals;
+using namespace std::literals::string_view_literals;
+
+inline u64 combine_hash(u64 a, u64 b) {
+  return a ^ (b + 0x9e3779b9 + (a << 6) + (a >> 2));
+}
+
+//
+// perf.cc
+//
+
+// Counter is used to collect statistics numbers.
+class Counter {
+public:
+  Counter(std::string_view name, i64 value = 0) : name(name), values(value) {
+    static std::mutex mu;
+    std::scoped_lock lock(mu);
+    instances.push_back(this);
+  }
+
+  Counter &operator++(int) {
+    if (enabled) [[unlikely]]
+      values.local()++;
+    return *this;
+  }
+
+  Counter &operator+=(int delta) {
+    if (enabled) [[unlikely]]
+      values.local() += delta;
+    return *this;
+  }
+
+  static void print();
+
+  static inline bool enabled = false;
+
+private:
+  i64 get_value();
+
+  std::string_view name;
+  tbb::enumerable_thread_specific<i64> values;
+
+  static inline std::vector<Counter *> instances;
+};
+
+// Timer and TimeRecord records elapsed time (wall clock time)
+// used by each pass of the linker.
+struct TimerRecord {
+  TimerRecord(std::string name, TimerRecord *parent = nullptr);
+  void stop();
+
+  std::string name;
+  TimerRecord *parent;
+  tbb::concurrent_vector<TimerRecord *> children;
+  i64 start;
+  i64 end;
+  i64 user;
+  i64 sys;
+  bool stopped = false;
+};
+
+void
+print_timer_records(tbb::concurrent_vector<std::unique_ptr<TimerRecord>> &);
+
+template <typename Context>
+class Timer {
+public:
+  Timer(Context &ctx, std::string name, Timer *parent = nullptr) {
+    record = new TimerRecord(name, parent ? parent->record : nullptr);
+    ctx.timer_records.emplace_back(record);
+  }
+
+  Timer(const Timer &) = delete;
+
+  ~Timer() {
+    record->stop();
+  }
+
+  void stop() {
+    record->stop();
+  }
+
+private:
+  TimerRecord *record;
+};
+
+//
+// Utility functions
+//
+
+// Some C++ libraries haven't implemented std::has_single_bit yet.
+inline bool has_single_bit(u64 val) {
+  return std::popcount(val) == 1;
+}
+
+// Some C++ libraries haven't implemented std::bit_ceil yet.
+inline u64 bit_ceil(u64 val) {
+  if (has_single_bit(val))
+    return val;
+  return 1LL << (64 - std::countl_zero(val));
+}
+
+inline u64 align_to(u64 val, u64 align) {
+  if (align == 0)
+    return val;
+  assert(has_single_bit(align));
+  return (val + align - 1) & ~(align - 1);
+}
+
+inline u64 align_down(u64 val, u64 align) {
+  assert(has_single_bit(align));
+  return val & ~(align - 1);
+}
+
+inline u64 bit(u64 val, i64 pos) {
+  return (val >> pos) & 1;
+};
+
+// Returns [hi:lo] bits of val.
+inline u64 bits(u64 val, u64 hi, u64 lo) {
+  return (val >> lo) & ((1LL << (hi - lo + 1)) - 1);
+}
+
+// Cast val to a signed N bit integer.
+// For example, sign_extend(x, 32) == (i32)x for any integer x.
+inline i64 sign_extend(u64 val, i64 n) {
+  return (i64)(val << (64 - n)) >> (64 - n);
+}
+
+inline bool is_int(u64 val, i64 n) {
+  return sign_extend(val, n) == val;
+}
+
+template <typename T, typename Compare = std::less<T>>
+void update_minimum(std::atomic<T> &atomic, u64 new_val, Compare cmp = {}) {
+  T old_val = atomic.load(std::memory_order_relaxed);
+  while (cmp(new_val, old_val) &&
+         !atomic.compare_exchange_weak(old_val, new_val,
+                                       std::memory_order_relaxed));
+}
+
+template <typename T, typename Compare = std::less<T>>
+void update_maximum(std::atomic<T> &atomic, u64 new_val, Compare cmp = {}) {
+  T old_val = atomic.load(std::memory_order_relaxed);
+  while (cmp(old_val, new_val) &&
+         !atomic.compare_exchange_weak(old_val, new_val,
+                                       std::memory_order_relaxed));
+}
+
+template <typename T>
+inline void append(std::vector<T> &x, const auto &y) {
+  x.insert(x.end(), y.begin(), y.end());
+}
+
+template <typename T>
+inline std::vector<T> flatten(std::vector<std::vector<T>> &vec) {
+  i64 size = 0;
+  for (std::vector<T> &v : vec)
+    size += v.size();
+
+  std::vector<T> ret;
+  ret.reserve(size);
+  for (std::vector<T> &v : vec)
+    append(ret, v);
+  return ret;
+}
+
+template <typename T>
+inline void remove_duplicates(std::vector<T> &vec) {
+  vec.erase(std::unique(vec.begin(), vec.end()), vec.end());
+}
+
+inline i64 write_string(void *buf, std::string_view str) {
+  memcpy(buf, str.data(), str.size());
+  *((u8 *)buf + str.size()) = '\0';
+  return str.size() + 1;
+}
+
+template <typename T>
+inline void write_vector(void *buf, const std::vector<T> &vec) {
+  if (!vec.empty())
+    memcpy(buf, vec.data(), vec.size() * sizeof(T));
+}
+
+inline void encode_uleb(std::vector<u8> &vec, u64 val) {
+  do {
+    u8 byte = val & 0x7f;
+    val >>= 7;
+    vec.push_back(val ? (byte | 0x80) : byte);
+  } while (val);
+}
+
+inline void encode_sleb(std::vector<u8> &vec, i64 val) {
+  for (;;) {
+    u8 byte = val & 0x7f;
+    val >>= 7;
+
+    bool neg = (byte & 0x40);
+    if ((val == 0 && !neg) || (val == -1 && neg)) {
+      vec.push_back(byte);
+      break;
+    }
+    vec.push_back(byte | 0x80);
+  }
+}
+
+inline i64 write_uleb(u8 *buf, u64 val) {
+  i64 i = 0;
+  do {
+    u8 byte = val & 0x7f;
+    val >>= 7;
+    buf[i++] = val ? (byte | 0x80) : byte;
+  } while (val);
+  return i;
+}
+
+inline u64 read_uleb(u8 **buf) {
+  u64 val = 0;
+  u8 shift = 0;
+  u8 byte;
+  do {
+    byte = *(*buf)++;
+    val |= (byte & 0x7f) << shift;
+    shift += 7;
+  } while (byte & 0x80);
+  return val;
+}
+
+inline u64 read_uleb(u8 *buf) {
+  u8 *tmp = buf;
+  return read_uleb(&tmp);
+}
+
+inline i64 read_sleb(u8 **buf) {
+  u64 val = 0;
+  u8 shift = 0;
+  u8 byte;
+  do {
+    byte = *(*buf)++;
+    val |= (byte & 0x7f) << shift;
+    shift += 7;
+  } while (byte & 0x80);
+  return sign_extend(val, shift);
+}
+
+inline i64 read_sleb(u8 *buf) {
+  u8 *tmp = buf;
+  return read_sleb(&tmp);
+}
+
+inline u64 read_uleb(std::string_view *str) {
+  u8 *start = (u8 *)str->data();
+  u8 *ptr = start;
+  u64 val = read_uleb(&ptr);
+  *str = str->substr(ptr - start);
+  return val;
+}
+
+inline u64 read_uleb(std::string_view str) {
+  std::string_view tmp = str;
+  return read_uleb(&tmp);
+}
+
+inline i64 uleb_size(u64 val) {
+  for (int i = 1; i < 9; i++)
+    if (val < (1LL << (7 * i)))
+      return i;
+  return 9;
+}
+
+inline void overwrite_uleb(u8 *loc, u64 val) {
+  while (*loc & 0b1000'0000) {
+    *loc++ = 0b1000'0000 | (val & 0b0111'1111);
+    val >>= 7;
+  }
+  *loc = val & 0b0111'1111;
+}
+
+static inline void pause() {
+#if defined(__x86_64__)
+  asm volatile("pause");
+#elif defined(__aarch64__)
+  asm volatile("yield");
+#elif defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_8A__)
+  asm volatile("yield");
+#endif
+}
+
+//
+// Concurrent Map
+//
+
+// This is an implementation of a fast concurrent hash map. Unlike
+// ordinary hash tables, this impl just aborts if it becomes full.
+// So you need to give a correct estimation of the final size before
+// using it. We use this hash map to uniquify pieces of data in
+// mergeable sections.
+//
+// We've implemented this ourselves because the performance of
+// conrurent hash map is critical for our linker.
+template <typename T>
+class ConcurrentMap {
+public:
+  ConcurrentMap() = default;
+
+  ConcurrentMap(i64 nbuckets) {
+    resize(nbuckets);
+  }
+
+  ~ConcurrentMap() {
+    if (entries) {
+#ifdef _WIN32
+      _aligned_free(entries);
+#else
+      munmap(entries, sizeof(Entry) * nbuckets);
+#endif
+    }
+  }
+
+  // In order to avoid unnecessary cache-line false sharing, we want
+  // to make this object to be aligned to a reasonably large
+  // power-of-two address.
+  struct alignas(32) Entry {
+    Atomic<const char *> key;
+    u32 keylen;
+    T value;
+  };
+
+  void resize(i64 nbuckets) {
+    assert(!entries);
+    this->nbuckets = std::max<i64>(MIN_NBUCKETS, bit_ceil(nbuckets));
+    i64 bufsize = sizeof(Entry) * this->nbuckets;
+
+    // Allocate a zero-initialized buffer. mmap() is faster than
+    // malloc()+memset(), and MAP_POPULATE pre-faults pages here to
+    // avoid CoW faults and TLB shootdowns under concurrent inserts.
+#ifdef _WIN32
+    entries = (Entry *)_aligned_malloc(bufsize, alignof(Entry));
+    memset((void *)entries, 0, bufsize);
+#elif MAP_POPULATE
+    entries = (Entry *)mmap(nullptr, bufsize, PROT_READ | PROT_WRITE,
+                            MAP_ANONYMOUS | MAP_PRIVATE | MAP_POPULATE, -1, 0);
+#else
+    entries = (Entry *)mmap(nullptr, bufsize, PROT_READ | PROT_WRITE,
+                            MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+#endif
+  }
+
+  std::pair<T *, bool> insert(std::string_view key, u64 hash, const T &val) {
+    assert(has_single_bit(nbuckets));
+
+    u64 begin = hash & (nbuckets - 1);
+    u64 mask = nbuckets / NUM_SHARDS - 1;
+
+    for (i64 i = 0; i < MAX_RETRY; i++) {
+      u64 idx = (begin & ~mask) | ((begin + i) & mask);
+      Entry &ent = entries[idx];
+
+      // It seems avoiding compare-and-swap is faster overall at least
+      // on my Zen4 machine, so do it.
+      if (const char *ptr = ent.key.load(std::memory_order_acquire);
+          ptr != nullptr && ptr != (char *)-1) {
+        if (key == std::string_view(ptr, ent.keylen))
+          return {&ent.value, false};
+        continue;
+      }
+
+      // Otherwise, use CAS to atomically claim the ownership of the slot.
+      const char *ptr = nullptr;
+      bool claimed = ent.key.compare_exchange_strong(ptr, (char *)-1,
+                                                     std::memory_order_acquire);
+
+      // If we successfully claimed the ownership of the slot,
+      // copy values to it.
+      if (claimed) {
+        new (&ent.value) T(val);
+        ent.keylen = key.size();
+        ent.key.store(key.data(), std::memory_order_release);
+        return {&ent.value, true};
+      }
+
+      // If someone is copying values to the slot, do busy wait.
+      while (ptr == (char *)-1) {
+        pause();
+        ptr = ent.key.load(std::memory_order_acquire);
+      }
+
+      // If the same key is already present, this is the slot we are
+      // looking for.
+      if (key == std::string_view(ptr, ent.keylen))
+        return {&ent.value, false};
+    }
+
+    std::cerr << "ConcurrentMap is full\n";
+    abort();
+  }
+
+  i64 get_idx(T *value) const {
+    uintptr_t addr = (uintptr_t)value - (uintptr_t)value % sizeof(Entry);
+    return (Entry *)addr - entries;
+  }
+
+  // Return a list of map entries sorted in a deterministic order.
+  std::vector<Entry *> get_sorted_entries(i64 shard_idx) {
+    if (nbuckets == 0)
+      return {};
+
+    i64 shard_size = nbuckets / NUM_SHARDS;
+    i64 begin = shard_idx * shard_size;
+    i64 end = begin + shard_size;
+
+    i64 sz = 0;
+    for (i64 i = begin; i < end; i++)
+      if (entries[i].key)
+        sz++;
+
+    std::vector<Entry *> vec;
+    vec.reserve(sz);
+
+    // Since the shard is circular, we need to handle the last entries
+    // as if they were next to the first entries.
+    while (begin < end && entries[end - 1].key)
+      vec.push_back(entries + --end);
+
+    // Find entries contiguous in the buckets and sort them.
+    i64 last = 0;
+    for (i64 i = begin; i < end;) {
+      while (i < end && entries[i].key)
+        vec.push_back(entries + i++);
+
+      std::sort(vec.begin() + last, vec.end(), [](Entry *a, Entry *b) {
+        if (a->keylen != b->keylen)
+          return a->keylen < b->keylen;
+        return memcmp(a->key, b->key, a->keylen) < 0;
+      });
+
+      last = vec.size();
+
+      while (i < end && !entries[i].key)
+        i++;
+    }
+    return vec;
+  }
+
+  std::vector<Entry *> get_sorted_entries_all() {
+    std::vector<std::vector<Entry *>> vec(NUM_SHARDS);
+    tbb::parallel_for((i64)0, NUM_SHARDS, [&](i64 i) {
+      vec[i] = get_sorted_entries(i);
+    });
+    return flatten(vec);
+  }
+
+  static constexpr i64 MIN_NBUCKETS = 4096;
+  static constexpr i64 NUM_SHARDS = 16;
+  static constexpr i64 MAX_RETRY = 256;
+
+  Entry *entries = nullptr;
+  u64 nbuckets = 0;
+};
+
+//
+// random.cc
+//
+
+void get_random_bytes(u8 *buf, i64 size);
+
+//
+// hyperloglog.cc
+//
+
+class HyperLogLog {
+public:
+  void insert(u64 hash) {
+    update_maximum(buckets[hash & (NBUCKETS - 1)], std::countl_zero(hash) + 1);
+  }
+
+  i64 get_cardinality() const;
+
+  void merge(const HyperLogLog &other) {
+    for (i64 i = 0; i < NBUCKETS; i++)
+      update_maximum(buckets[i], other.buckets[i]);
+  }
+
+private:
+  static constexpr i64 NBUCKETS = 2048;
+  static constexpr double ALPHA = 0.79402;
+
+  Atomic<u8> buckets[NBUCKETS];
+};
+
+//
+// aho-corasick.cc
+//
+
+class AhoCorasick {
+public:
+  bool add(std::string_view pat, i64 val);
+  bool empty() const { return nodes.empty(); }
+  void compile();
+  i64 find(std::string_view str);
+
+  static bool can_handle(std::string_view str);
+
+private:
+  struct TrieNode {
+    TrieNode() { children.fill(-1); }
+    i64 value = -1;
+    i32 suffix_link = -1;
+    std::array<i32, 256> children;
+  };
+
+  void fix_suffix_links(i64 idx);
+  void fix_values();
+
+  std::vector<TrieNode> nodes;
+};
+
+//
+// glob.cc
+//
+
+class MultiGlob {
+public:
+  bool add(std::string_view pat, i64 val);
+  bool empty() const { return patterns.empty(); }
+  void compile();
+  i64 find(std::string_view str);
+
+  struct State {
+    std::bitset<256> incoming_edge;
+    bool is_star = false;
+  };
+
+  struct GlobPattern {
+    std::vector<State> states;
+    i64 value = -1;
+  };
+
+private:
+  std::vector<GlobPattern> patterns;
+  Bitvector start_states;
+  Bitvector star_mask;
+  Bitvector char_mask[256];
+};
+
+class Glob {
+public:
+  bool add(std::string_view pat, i64 val);
+  bool empty() const { return multi_glob.empty() && aho_corasick.empty(); }
+  i64 find(std::string_view str);
+
+private:
+  std::once_flag once;
+  bool is_compiled = false;
+
+  MultiGlob multi_glob;
+  AhoCorasick aho_corasick;
+};
+
+//
+// filepath.cc
+//
+
+inline std::filesystem::path path_dirname(std::string_view path) {
+  return std::filesystem::path(path).parent_path();
+}
+
+inline std::string path_filename(std::string_view path) {
+  return std::filesystem::path(path).filename().string();
+}
+
+inline std::string path_clean(std::string_view path) {
+  return std::filesystem::path(path).lexically_normal().string();
+}
+
+std::string get_self_path();
+
+//
+// demangle.cc
+//
+
+std::optional<std::string_view> demangle_cpp(std::string_view name);
+std::optional<std::string_view> demangle_rust(std::string_view name);
+
+//
+// crc32.cc
+//
+
+u32 compute_crc32(u32 crc, u8 *buf, i64 len);
+std::vector<u8> crc32_solve(u32 current, u32 desired);
+
+//
+// compress.cc
+//
+
+class Compressor {
+public:
+  virtual void write_to(u8 *buf) = 0;
+  virtual ~Compressor();
+  i64 compressed_size = 0;
+
+protected:
+  std::vector<std::span<u8>> shards;
+};
+
+class ZlibCompressor : public Compressor {
+public:
+  ZlibCompressor(u8 *buf, i64 size, i64 level);
+  void write_to(u8 *buf) override;
+
+private:
+  u32 checksum = 0;
+};
+
+class ZstdCompressor : public Compressor {
+public:
+  ZstdCompressor(u8 *buf, i64 size, i64 level);
+  void write_to(u8 *buf) override;
+};
+
+//
+// tar.cc
+//
+
+// TarFile is a class to create a tar file.
+//
+// If you pass `--repro` to mold, mold collects all input files and
+// put them into `<output-file-path>.repro.tar`, so that it is easy to
+// run the same command with the same command line arguments.
+class TarWriter {
+public:
+  static std::unique_ptr<TarWriter>
+  open(std::string output_path, std::string basedir);
+
+  ~TarWriter();
+  void append(std::string path, std::string_view data);
+
+private:
+  TarWriter(FILE *out, std::string basedir) : out(out), basedir(basedir) {}
+
+  FILE *out = nullptr;
+  std::string basedir;
+};
+
+} // namespace mold

lib/perf.cc

@@ -1,10 +1,13 @@
-#include "common.h"
+#include "lib.h"
 
 #include <functional>
 #include <iomanip>
 #include <ios>
+#include <tbb/concurrent_vector.h>
 
-#ifndef _WIN32
+#ifdef _WIN32
+#include <windows.h>
+#else
 #include <sys/resource.h>
 #include <sys/time.h>
 #endif
@@ -16,9 +19,7 @@ i64 Counter::get_value() {
 }
 
 void Counter::print() {
-  sort(instances, [](Counter *a, Counter *b) {
-    return a->get_value() > b->get_value();
-  });
+  ranges::stable_sort(instances, {}, [](Counter *x) { return x->get_value(); });
 
   for (Counter *c : instances)
     std::cout << std::setw(20) << std::right << c->name
@@ -26,19 +27,13 @@ void Counter::print() {
 }
 
 static i64 now_nsec() {
-#ifdef _WIN32
   return (i64)std::chrono::steady_clock::now().time_since_epoch().count();
-#else
-  struct timespec t;
-  clock_gettime(CLOCK_MONOTONIC, &t);
-  return (i64)t.tv_sec * 1000000000 + t.tv_nsec;
-#endif
 }
 
 static std::pair<i64, i64> get_usage() {
 #ifdef _WIN32
   auto to_nsec = [](FILETIME t) -> i64 {
-    return ((u64)t.dwHighDateTime << 32 + (u64)t.dwLowDateTime) * 100;
+    return (((u64)t.dwHighDateTime << 32) + (u64)t.dwLowDateTime) * 100;
   };
 
   FILETIME creation, exit, kernel, user;
@@ -46,7 +41,7 @@ static std::pair<i64, i64> get_usage() {
   return {to_nsec(user), to_nsec(kernel)};
 #else
   auto to_nsec = [](struct timeval t) -> i64 {
-    return (i64)t.tv_sec * 1000000000 + t.tv_usec * 1000;
+    return (i64)t.tv_sec * 1'000'000'000 + t.tv_usec * 1'000;
   };
 
   struct rusage ru;
@@ -79,15 +74,13 @@ void TimerRecord::stop() {
 
 static void print_rec(TimerRecord &rec, i64 indent) {
   printf(" % 8.3f % 8.3f % 8.3f  %s%s\n",
-         ((double)rec.user / 1000000000),
-         ((double)rec.sys / 1000000000),
-         (((double)rec.end - rec.start) / 1000000000),
+         ((double)rec.user / 1'000'000'000),
+         ((double)rec.sys / 1'000'000'000),
+         (((double)rec.end - rec.start) / 1'000'000'000),
          std::string(indent * 2, ' ').c_str(),
          rec.name.c_str());
 
-  sort(rec.children, [](TimerRecord *a, TimerRecord *b) {
-    return a->start < b->start;
-  });
+  ranges::stable_sort(rec.children, {}, &TimerRecord::start);
 
   for (TimerRecord *child : rec.children)
     print_rec(*child, indent + 1);

lib/random.cc

@@ -0,0 +1,20 @@
+#include "lib.h"
+
+#include <random>
+
+namespace mold {
+
+void get_random_bytes(u8 *buf, i64 size) {
+  std::random_device rand;
+  i64 i = 0;
+
+  for (; i < size - 4; i += 4) {
+    u32 val = rand();
+    memcpy(buf + i, &val, 4);
+  }
+
+  u32 val = rand();
+  memcpy(buf + i, &val, size - i);
+}
+
+} // namespace mold

lib/siphash.h

@@ -0,0 +1,144 @@
+// This is a header-only C++20 implementation of SipHash based on the
+// reference implementation. To use, just copy this header file into
+// your project and #include it.
+//
+// https://github.com/rui314/siphash/blob/main/siphash.h
+
+#include <bit>
+#include <cstdint>
+#include <cstring>
+
+template <int C_ROUNDS, int D_ROUNDS, int OUTLEN>
+class SipHashTmpl {
+public:
+  static_assert(OUTLEN == 64 || OUTLEN == 128);
+
+  SipHashTmpl(void *key) {
+    uint64_t k0 = read64(key);
+    uint64_t k1 = read64((char *)key + 8);
+
+    v0 = 0x736f6d6570736575 ^ k0;
+    v1 = 0x646f72616e646f6d ^ k1;
+    v2 = 0x6c7967656e657261 ^ k0;
+    v3 = 0x7465646279746573 ^ k1;
+
+    if (OUTLEN == 128)
+      v1 ^= 0xee;
+  }
+
+  void update(void *msgp, int64_t msglen) {
+    char *msg = (char *)msgp;
+    sum += msglen;
+
+    if (buflen) {
+      if (buflen + msglen < 8) {
+        memcpy(buf + buflen, msg, msglen);
+        buflen += msglen;
+        return;
+      }
+
+      int j = 8 - buflen;
+      memcpy(buf + buflen, msg, j);
+      compress(read64(buf));
+
+      msg += j;
+      msglen -= j;
+      buflen = 0;
+    }
+
+    while (msglen >= 8) {
+      compress(read64(msg));
+      msg += 8;
+      msglen -= 8;
+    }
+
+    memcpy(buf, msg, msglen);
+    buflen = msglen;
+  }
+
+  void finish(void *out) {
+    memset(buf + buflen, 0, 8 - buflen);
+    compress(((uint64_t)sum << 56) | read64(buf));
+
+    v2 ^= (OUTLEN == 128) ? 0xee : 0xff;
+    finalize();
+    write64(out, v0 ^ v1 ^ v2 ^ v3);
+
+    if (OUTLEN == 128) {
+      v1 ^= 0xdd;
+      finalize();
+      write64((char *)out + 8, v0 ^ v1 ^ v2 ^ v3);
+    }
+  }
+
+  static void hash(void *out, void *key, void *in, int inlen) {
+    SipHashTmpl<C_ROUNDS, D_ROUNDS, OUTLEN> h(key);
+    h.update(in, inlen);
+    h.finish(out);
+  }
+
+private:
+  uint64_t v0, v1, v2, v3;
+  uint8_t buf[8];
+  uint8_t buflen = 0;
+  uint8_t sum = 0;
+
+  uint64_t read64(void *loc) {
+    uint64_t val;
+    memcpy(&val, loc, 8);
+    if (std::endian::native == std::endian::big)
+      val = bswap(val);
+    return val;
+  }
+
+  void write64(void *loc, uint64_t val) {
+    if (std::endian::native == std::endian::big)
+      val = bswap(val);
+    memcpy(loc, &val, 8);
+  }
+
+  uint64_t bswap(uint64_t val) {
+    return ((val << 56) & 0xff00000000000000) |
+           ((val << 40) & 0x00ff000000000000) |
+           ((val << 24) & 0x0000ff0000000000) |
+           ((val << 8)  & 0x000000ff00000000) |
+           ((val >> 8)  & 0x00000000ff000000) |
+           ((val >> 24) & 0x0000000000ff0000) |
+           ((val >> 40) & 0x000000000000ff00) |
+           ((val >> 56) & 0x00000000000000ff);
+  }
+
+  void round() {
+    v0 += v1;
+    v1 = std::rotl(v1, 13);
+    v1 ^= v0;
+    v0 = std::rotl(v0, 32);
+    v2 += v3;
+    v3 = std::rotl(v3, 16);
+    v3 ^= v2;
+    v0 += v3;
+    v3 = std::rotl(v3, 21);
+    v3 ^= v0;
+    v2 += v1;
+    v1 = std::rotl(v1, 17);
+    v1 ^= v2;
+    v2 = std::rotl(v2, 32);
+  }
+
+  void compress(uint64_t m) {
+    v3 ^= m;
+    for (int i = 0; i < C_ROUNDS; i++)
+      round();
+    v0 ^= m;
+  }
+
+  void finalize() {
+    for (int i = 0; i < D_ROUNDS; i++)
+      round();
+  }
+};
+
+using SipHash = SipHashTmpl<2, 4, 64>;
+using SipHash128 = SipHashTmpl<2, 4, 128>;
+using SipHash13 = SipHashTmpl<1, 3, 64>;
+using SipHash13_128 = SipHashTmpl<1, 3, 128>;

lib/tar.cc

@@ -1,7 +1,15 @@
-#include "common.h"
+// This file contains functions to create a tar file.
+
+#include "lib.h"
+
+#ifdef _WIN32
+# define ftruncate _chsize_s
+#endif
 
 namespace mold {
 
+static constexpr i64 BLOCK_SIZE = 512;
+
 // A tar file consists of one or more Ustar header followed by data.
 // Each Ustar header represents a single file in an archive.
 //
@@ -11,26 +19,6 @@ namespace mold {
 //
 // For simplicity, we always emit a PAX header even for a short filename.
 struct UstarHeader {
-  UstarHeader() {
-    memset(this, 0, sizeof(*this));
-  }
-
-  void finalize() {
-    memset(checksum, ' ', sizeof(checksum));
-    memcpy(magic, "ustar", 5);
-    memcpy(version, "00", 2);
-
-    // Compute checksum
-    int sum = 0;
-    for (i64 i = 0; i < sizeof(*this); i++)
-      sum += ((u8 *)this)[i];
-
-    // We need to convince the compiler that sum isn't too big to silence
-    // -Werror=format-truncation.
-    ASSUME(sum < 01'000'000);
-    snprintf(checksum, sizeof(checksum), "%06o", sum);
-  }
-
   char name[100];
   char mode[8];
   char uid[8];
@@ -50,6 +38,25 @@ struct UstarHeader {
   char pad[12];
 };
 
+static_assert(sizeof(UstarHeader) == BLOCK_SIZE);
+
+static void finalize(UstarHeader &hdr) {
+  memset(hdr.checksum, ' ', sizeof(hdr.checksum));
+  memcpy(hdr.magic, "ustar", 5);
+  memcpy(hdr.version, "00", 2);
+
+  // Compute checksum
+  int sum = 0;
+  for (i64 i = 0; i < sizeof(hdr); i++)
+    sum += ((u8 *)&hdr)[i];
+
+  // We need to convince the compiler that sum isn't too big to silence
+  // -Werror=format-truncation.
+  if (sum >= 01'000'000)
+    unreachable();
+  snprintf(hdr.checksum, sizeof(hdr.checksum), "%06o", sum);
+}
+
 static std::string encode_path(std::string basedir, std::string path) {
   path = path_clean(basedir + "/" + path);
 
@@ -76,13 +83,16 @@ TarWriter::~TarWriter() {
 
 void TarWriter::append(std::string path, std::string_view data) {
   // Write PAX header
-  static_assert(sizeof(UstarHeader) == BLOCK_SIZE);
-  UstarHeader pax;
+  UstarHeader pax = {};
 
   std::string attr = encode_path(basedir, path);
+
+  if (attr.size() >= 0100'000'000'000)
+    unreachable();
   snprintf(pax.size, sizeof(pax.size), "%011zo", attr.size());
+  pax.name[0] = '/';
   pax.typeflag[0] = 'x';
-  pax.finalize();
+  finalize(pax);
   fwrite(&pax, sizeof(pax), 1, out);
 
   // Write pathname
@@ -90,23 +100,20 @@ void TarWriter::append(std::string path, std::string_view data) {
   fseek(out, align_to(ftell(out), BLOCK_SIZE), SEEK_SET);
 
   // Write Ustar header
-  UstarHeader ustar;
+  UstarHeader ustar = {};
   memcpy(ustar.mode, "0000664", 8);
+  if (data.size() >= 0100'000'000'000)
+    unreachable();
   snprintf(ustar.size, sizeof(ustar.size), "%011zo", data.size());
-  ustar.finalize();
+  finalize(ustar);
   fwrite(&ustar, sizeof(ustar), 1, out);
 
   // Write file contents
   fwrite(data.data(), data.size(), 1, out);
   fseek(out, align_to(ftell(out), BLOCK_SIZE), SEEK_SET);
 
-  // A tar file must ends with two empty blocks, so write such
-  // terminator and seek back.
-  u8 terminator[BLOCK_SIZE * 2] = {};
-  fwrite(&terminator, BLOCK_SIZE * 2, 1, out);
-  fseek(out, -BLOCK_SIZE * 2, SEEK_END);
-
-  assert(ftell(out) % BLOCK_SIZE == 0);
+  // A tar file must ends with two empty blocks
+  (void)!ftruncate(fileno(out), ftell(out) + BLOCK_SIZE * 2);
 }
 
 } // namespace mold

lib/update-git-hash.cmake

@@ -17,11 +17,11 @@ if(EXISTS "${SOURCE_DIR}/.git/HEAD")
 endif()
 
 # Create new file contents and update a given file if necessary.
-set(NEW_CONTENTS "#include <string>
-namespace mold {
-std::string mold_git_hash = \"${HASH}\";
-}
-")
+if("${HASH}" STREQUAL "")
+  set(NEW_CONTENTS "")
+else()
+  set(NEW_CONTENTS "#define MOLD_GIT_HASH \"${HASH}\"\n")
+endif()
 
 if(EXISTS "${OUTPUT_FILE}")
   file(READ "${OUTPUT_FILE}" OLD_CONTENTS)

src/arch-arm32.cc

@@ -0,0 +1,916 @@
+// ARM32 is a bit special from the linker's viewpoint because ARM
+// processors support two different instruction encodings: Thumb and
+// ARM (in a narrower sense). Thumb instructions are either 16 bits or
+// 32 bits, while ARM instructions are all 32 bits. Feature-wise,
+// Thumb is a subset of ARM, so not all ARM instructions are
+// representable in Thumb.
+//
+// ARM processors originally supported only ARM instructions. Thumb
+// instructions were later added to increase code density.
+//
+// ARM processors runs in either ARM mode or Thumb mode. The mode can
+// be switched using BX (branch and mode exchange)-family instructions.
+// We need to use that instructions to, for example, call a function
+// encoded in Thumb from a function encoded in ARM. Sometimes, the
+// linker even has to emit interworking thunk code to switch mode.
+//
+// ARM instructions are aligned to 4 byte boundaries. Thumb are to 2
+// byte boundaries. So the least significant bit of a function address
+// is always 0.
+//
+// To distinguish Thumb functions from ARM fucntions, the LSB of a
+// function address is repurposed as a boolean flag. If the LSB is 0,
+// the function referred to by the address is encoded in ARM;
+// otherwise, Thumb.
+//
+// For example, if a symbol `foo` is of type STT_FUNC and has value
+// 0x2001, `foo` is a function using Thumb instructions whose address
+// is 0x2000 (not 0x2001, as Thumb instructions are always 2-byte
+// aligned). Likewise, if a function pointer has value 0x2001, it
+// refers a Thumb function at 0x2000.
+//
+// https://github.com/ARM-software/abi-aa/blob/main/aaelf32/aaelf32.rst
+
+#if MOLD_ARM32LE || MOLD_ARM32BE
+
+#include "mold.h"
+
+#include <tbb/parallel_for.h>
+#include <tbb/parallel_for_each.h>
+
+namespace mold {
+
+using E = MOLD_TARGET;
+
+template <>
+i64 get_addend(u8 *loc, const ElfRel<E> &rel) {
+  U32<E> *arm = (U32<E> *)loc;
+  U16<E> *thm = (U16<E> *)loc;
+
+  switch (rel.r_type) {
+  case R_ARM_ABS32:
+  case R_ARM_REL32:
+  case R_ARM_BASE_PREL:
+  case R_ARM_GOTOFF32:
+  case R_ARM_GOT_PREL:
+  case R_ARM_GOT_BREL:
+  case R_ARM_TLS_GD32:
+  case R_ARM_TLS_LDM32:
+  case R_ARM_TLS_LDO32:
+  case R_ARM_TLS_IE32:
+  case R_ARM_TLS_LE32:
+  case R_ARM_TLS_GOTDESC:
+  case R_ARM_TARGET1:
+  case R_ARM_TARGET2:
+    return (I32<E>)*arm;
+  case R_ARM_THM_JUMP8:
+    return sign_extend(thm[0], 8) << 1;
+  case R_ARM_THM_JUMP11:
+    return sign_extend(thm[0], 11) << 1;
+  case R_ARM_THM_JUMP19: {
+    // https://developer.arm.com/documentation/ddi0597/2024-12/Base-Instructions/B--Branch-
+    u32 S = bit(thm[0], 10);
+    u32 J2 = bit(thm[1], 11);
+    u32 J1 = bit(thm[1], 13);
+    u32 imm6 = bits(thm[0], 5, 0);
+    u32 imm11 = bits(thm[1], 10, 0);
+    u32 val = (S << 20) | (J2 << 19) | (J1 << 18) | (imm6 << 12) | (imm11 << 1);
+    return sign_extend(val, 21);
+  }
+  case R_ARM_THM_CALL:
+  case R_ARM_THM_JUMP24:
+  case R_ARM_THM_TLS_CALL: {
+    // https://developer.arm.com/documentation/ddi0597/2024-12/Base-Instructions/BL--BLX--immediate---Branch-with-Link-and-optional-Exchange--immediate--
+    u32 S = bit(thm[0], 10);
+    u32 J1 = bit(thm[1], 13);
+    u32 J2 = bit(thm[1], 11);
+    u32 I1 = !(J1 ^ S);
+    u32 I2 = !(J2 ^ S);
+    u32 imm10 = bits(thm[0], 9, 0);
+    u32 imm11 = bits(thm[1], 10, 0);
+    u32 val = (S << 24) | (I1 << 23) | (I2 << 22) | (imm10 << 12) | (imm11 << 1);
+    return sign_extend(val, 25);
+  }
+  case R_ARM_CALL:
+  case R_ARM_JUMP24:
+  case R_ARM_PLT32:
+  case R_ARM_TLS_CALL:
+    return sign_extend(*arm, 24) << 2;
+  case R_ARM_MOVW_PREL_NC:
+  case R_ARM_MOVW_ABS_NC:
+  case R_ARM_MOVT_PREL:
+  case R_ARM_MOVT_ABS: {
+    // https://developer.arm.com/documentation/ddi0597/2024-12/Base-Instructions/MOV--MOVS--immediate---Move--immediate--
+    u32 imm4 = bits(*arm, 19, 16);
+    u32 imm12 = bits(*arm, 11, 0);
+    u32 val = (imm4 << 12) | imm12;
+    return sign_extend(val, 16);
+  }
+  case R_ARM_PREL31:
+    return sign_extend(*arm, 31);
+  case R_ARM_THM_MOVW_PREL_NC:
+  case R_ARM_THM_MOVW_ABS_NC:
+  case R_ARM_THM_MOVT_PREL:
+  case R_ARM_THM_MOVT_ABS: {
+    // https://developer.arm.com/documentation/ddi0597/2024-12/Base-Instructions/MOVT--Move-Top-
+    u32 imm4 = bits(thm[0], 3, 0);
+    u32 i = bit(thm[0], 10);
+    u32 imm3 = bits(thm[1], 14, 12);
+    u32 imm8 = bits(thm[1], 7, 0);
+    u32 val = (imm4 << 12) | (i << 11) | (imm3 << 8) | imm8;
+    return sign_extend(val, 16);
+  }
+  default:
+    return 0;
+  }
+}
+
+static void write_arm_mov(u8 *loc, u32 val) {
+  u32 imm12 = bits(val, 11, 0);
+  u32 imm4 = bits(val, 15, 12);
+  *(U32<E> *)loc = (*(U32<E> *)loc & 0xfff0'f000) | (imm4 << 16) | imm12;
+}
+
+static void write_thm_b21(u8 *loc, u32 val) {
+  u32 S = bit(val, 20);
+  u32 J2 = bit(val, 19);
+  u32 J1 = bit(val, 18);
+  u32 imm6 = bits(val, 17, 12);
+  u32 imm11 = bits(val, 11, 1);
+
+  U16<E> *buf = (U16<E> *)loc;
+  buf[0] = (buf[0] & 0b1111'1011'1100'0000) | (S << 10) | imm6;
+  buf[1] = (buf[1] & 0b1101'0000'0000'0000) | (J1 << 13) | (J2 << 11) | imm11;
+}
+
+static void write_thm_b25(u8 *loc, u32 val) {
+  u32 S = bit(val, 24);
+  u32 I1 = bit(val, 23);
+  u32 I2 = bit(val, 22);
+  u32 J1 = !I1 ^ S;
+  u32 J2 = !I2 ^ S;
+  u32 imm10 = bits(val, 21, 12);
+  u32 imm11 = bits(val, 11, 1);
+
+  U16<E> *buf = (U16<E> *)loc;
+  buf[0] = (buf[0] & 0b1111'1000'0000'0000) | (S << 10) | imm10;
+  buf[1] = (buf[1] & 0b1101'0000'0000'0000) | (J1 << 13) | (J2 << 11) | imm11;
+}
+
+static void write_thm_mov(u8 *loc, u32 val) {
+  u32 imm4 = bits(val, 15, 12);
+  u32 i = bit(val, 11);
+  u32 imm3 = bits(val, 10, 8);
+  u32 imm8 = bits(val, 7, 0);
+
+  U16<E> *buf = (U16<E> *)loc;
+  buf[0] = (buf[0] & 0b1111'1011'1111'0000) | (i << 10) | imm4;
+  buf[1] = (buf[1] & 0b1000'1111'0000'0000) | (imm3 << 12) | imm8;
+}
+
+template <>
+void write_addend(u8 *loc, i64 val, const ElfRel<E> &rel) {
+  switch (rel.r_type) {
+  case R_ARM_NONE:
+    break;
+  case R_ARM_ABS32:
+  case R_ARM_REL32:
+  case R_ARM_BASE_PREL:
+  case R_ARM_GOTOFF32:
+  case R_ARM_GOT_PREL:
+  case R_ARM_GOT_BREL:
+  case R_ARM_TLS_GD32:
+  case R_ARM_TLS_LDM32:
+  case R_ARM_TLS_LDO32:
+  case R_ARM_TLS_IE32:
+  case R_ARM_TLS_LE32:
+  case R_ARM_TLS_GOTDESC:
+  case R_ARM_TARGET1:
+  case R_ARM_TARGET2:
+    *(U32<E> *)loc = val;
+    break;
+  case R_ARM_THM_JUMP8:
+    *(U16<E> *)loc = (*(U16<E> *)loc & 0xff00) | bits(val, 8, 1);
+    break;
+  case R_ARM_THM_JUMP11:
+    *(U16<E> *)loc = (*(U16<E> *)loc & 0xf800) | bits(val, 11, 1);
+    break;
+  case R_ARM_THM_CALL:
+  case R_ARM_THM_JUMP24:
+  case R_ARM_THM_TLS_CALL:
+    write_thm_b25(loc, val);
+    break;
+  case R_ARM_CALL:
+  case R_ARM_JUMP24:
+  case R_ARM_PLT32:
+    *(U32<E> *)loc = (*(U32<E> *)loc & 0xff00'0000) | bits(val, 25, 2);
+    break;
+  case R_ARM_MOVW_PREL_NC:
+  case R_ARM_MOVW_ABS_NC:
+  case R_ARM_MOVT_PREL:
+  case R_ARM_MOVT_ABS:
+    write_arm_mov(loc, val);
+    break;
+  case R_ARM_PREL31:
+    *(U32<E> *)loc = (*(U32<E> *)loc & 0x8000'0000) | (val & 0x7fff'ffff);
+    break;
+  case R_ARM_THM_MOVW_PREL_NC:
+  case R_ARM_THM_MOVW_ABS_NC:
+  case R_ARM_THM_MOVT_PREL:
+  case R_ARM_THM_MOVT_ABS:
+    write_thm_mov(loc, val);
+    break;
+  default:
+    unreachable();
+  }
+}
+
+template <>
+void write_plt_header(Context<E> &ctx, u8 *buf) {
+  constexpr ul32 insn[] = {
+    0xe52d'e004, //    push {lr}
+    0xe59f'e004, //    ldr lr, 2f
+    0xe08f'e00e, // 1: add lr, pc, lr
+    0xe5be'f008, //    ldr pc, [lr, #8]!
+    0x0000'0000, // 2: .word .got.plt - 1b - 8
+    0x0000'0000, //    (padding)
+    0x0000'0000, //    (padding)
+    0x0000'0000, //    (padding)
+  };
+
+  memcpy(buf, insn, sizeof(insn));
+  *(U32<E> *)(buf + 16) = ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 16;
+}
+
+static constexpr ul32 plt_entry[] = {
+  0xe59f'c004, // 1: ldr ip, 2f
+  0xe08c'c00f, //    add ip, ip, pc
+  0xe59c'f000, //    ldr pc, [ip]
+  0x0000'0000, // 2: .word sym@GOT - 1b
+};
+
+template <>
+void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
+  memcpy(buf, plt_entry, sizeof(plt_entry));
+  *(U32<E> *)(buf + 12) = sym.get_gotplt_addr(ctx) - sym.get_plt_addr(ctx) - 12;
+}
+
+template <>
+void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
+  memcpy(buf, plt_entry, sizeof(plt_entry));
+  *(U32<E> *)(buf + 12) = sym.get_got_pltgot_addr(ctx) - sym.get_plt_addr(ctx) - 12;
+}
+
+template <>
+void EhFrameSection<E>::apply_eh_reloc(Context<E> &ctx, const ElfRel<E> &rel,
+                                       u64 offset, u64 val) {
+  u8 *loc = ctx.buf + this->shdr.sh_offset + offset;
+
+  switch (rel.r_type) {
+  case R_NONE:
+    break;
+  case R_ARM_ABS32:
+    *(U32<E> *)loc = val;
+    break;
+  case R_ARM_REL32:
+    *(U32<E> *)loc = val - this->shdr.sh_addr - offset;
+    break;
+  default:
+    Fatal(ctx) << "unsupported relocation in .eh_frame: " << rel;
+  }
+}
+
+template <>
+void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
+  std::span<const ElfRel<E>> rels = get_rels(ctx);
+
+  for (i64 i = 0; i < rels.size(); i++) {
+    const ElfRel<E> &rel = rels[i];
+    if (rel.r_type == R_NONE || rel.r_type == R_ARM_V4BX)
+      continue;
+
+    Symbol<E> &sym = *file.symbols[rel.r_sym];
+    u8 *loc = base + rel.r_offset;
+
+    u64 S = sym.get_addr(ctx);
+    u64 A = get_addend(*this, rel);
+    u64 P = get_addr() + rel.r_offset;
+    u64 T = S & 1;
+    u64 G = sym.get_got_idx(ctx) * sizeof(Word<E>);
+    u64 GOT = ctx.got->shdr.sh_addr;
+
+    auto check = [&](i64 val, i64 lo, i64 hi) {
+      check_range(ctx, i, val, lo, hi);
+    };
+
+    auto get_thumb_thunk_addr = [&] { return sym.get_thunk_addr(ctx, P); };
+    auto get_arm_thunk_addr   = [&] { return sym.get_thunk_addr(ctx, P) + 4; };
+
+    auto get_tlsdesc_trampoline_addr = [&] {
+      auto it = ranges::upper_bound(output_section->thunks, P, {},
+                                    [](std::unique_ptr<Thunk<E>> &thunk) {
+        return thunk->get_addr();
+      });
+      return (*it)->get_addr();
+    };
+
+    switch (rel.r_type) {
+    case R_ARM_ABS32:
+    case R_ARM_TARGET1:
+      break;
+    case R_ARM_REL32:
+      *(U32<E> *)loc = S + A - P;
+      break;
+    case R_ARM_THM_CALL: {
+      if (sym.is_remaining_undef_weak()) {
+        // On ARM, calling an weak undefined symbol jumps to the
+        // next instruction.
+        *(U32<E> *)loc = 0x8000'f3af; // NOP.W
+        break;
+      }
+
+      // THM_CALL relocation refers to either BL or BLX instruction.
+      // They are different in only one bit. We need to use BL if
+      // the jump target is Thumb. Otherwise, use BLX.
+      i64 val1 = S + A - P;
+      i64 val2 = align_to(S + A - P, 4);
+
+      if (T && is_int(val1, 25)) {
+        *(U16<E> *)(loc + 2) |= 0x1000;  // BL
+        write_thm_b25(loc, val1);
+      } else if (!T && is_int(val2, 25)) {
+        *(U16<E> *)(loc + 2) &= ~0x1000; // BLX
+        write_thm_b25(loc, val2);
+      } else {
+        *(U16<E> *)(loc + 2) |= 0x1000;  // BL
+        write_thm_b25(loc, get_thumb_thunk_addr() + A - P);
+      }
+      break;
+    }
+    case R_ARM_BASE_PREL:
+      *(U32<E> *)loc = GOT + A - P;
+      break;
+    case R_ARM_GOTOFF32:
+      *(U32<E> *)loc = ((S + A) | T) - GOT;
+      break;
+    case R_ARM_GOT_PREL:
+    case R_ARM_TARGET2:
+      *(U32<E> *)loc = GOT + G + A - P;
+      break;
+    case R_ARM_GOT_BREL:
+      *(U32<E> *)loc = G + A;
+      break;
+    case R_ARM_CALL: {
+      if (sym.is_remaining_undef_weak()) {
+        *(U32<E> *)loc = 0xe320'f000; // NOP
+        break;
+      }
+
+      // Just like THM_CALL, ARM_CALL relocation refers to either BL or
+      // BLX instruction. We may need to rewrite BL → BLX or BLX → BL.
+      bool is_bl = ((*(U32<E> *)loc & 0xff00'0000) == 0xeb00'0000);
+      bool is_blx = ((*(U32<E> *)loc & 0xfe00'0000) == 0xfa00'0000);
+      if (!is_bl && !is_blx)
+        Fatal(ctx) << *this << ": R_ARM_CALL refers to neither BL nor BLX";
+
+      i64 val = S + A - P;
+      if (is_int(val, 26)) {
+        if (T) {
+          *(U32<E> *)loc = 0xfa00'0000; // BLX
+          *(U32<E> *)loc |= (bit(val, 1) << 24) | bits(val, 25, 2);
+        } else {
+          *(U32<E> *)loc = 0xeb00'0000; // BL
+          *(U32<E> *)loc |= bits(val, 25, 2);
+        }
+      } else {
+        *(U32<E> *)loc = 0xeb00'0000; // BL
+        *(U32<E> *)loc |= bits(get_arm_thunk_addr() + A - P, 25, 2);
+      }
+      break;
+    }
+    case R_ARM_JUMP24: {
+      if (sym.is_remaining_undef_weak()) {
+        *(U32<E> *)loc = 0xe320'f000; // NOP
+        break;
+      }
+
+      // These relocs refers to a B (unconditional branch) instruction.
+      // Unlike BL or BLX, we can't rewrite B to BX in place when the
+      // processor mode switch is required because BX doesn't takes an
+      // immediate; it takes only a register. So if mode switch is
+      // required, we jump to a linker-synthesized thunk which does the
+      // job with a longer code sequence.
+      i64 val = S + A - P;
+      if (T || !is_int(val, 26))
+        val = get_arm_thunk_addr() + A - P;
+      *(U32<E> *)loc = (*(U32<E> *)loc & 0xff00'0000) | bits(val, 25, 2);
+      break;
+    }
+    case R_ARM_PLT32:
+      if (sym.is_remaining_undef_weak()) {
+        *(U32<E> *)loc = 0xe320'f000; // NOP
+      } else {
+        u64 val = (T ? get_arm_thunk_addr() : S) + A - P;
+        *(U32<E> *)loc = (*(U32<E> *)loc & 0xff00'0000) | bits(val, 25, 2);
+      }
+      break;
+    case R_ARM_THM_JUMP8:
+      check(S + A - P, -(1 << 8), 1 << 8);
+      *(U16<E> *)loc &= 0xff00;
+      *(U16<E> *)loc |= bits(S + A - P, 8, 1);
+      break;
+    case R_ARM_THM_JUMP11:
+      check(S + A - P, -(1 << 11), 1 << 11);
+      *(U16<E> *)loc &= 0xf800;
+      *(U16<E> *)loc |= bits(S + A - P, 11, 1);
+      break;
+    case R_ARM_THM_JUMP19:
+      check(S + A - P, -(1 << 20), 1 << 20);
+      write_thm_b21(loc, S + A - P);
+      break;
+    case R_ARM_THM_JUMP24: {
+      if (sym.is_remaining_undef_weak()) {
+        *(U32<E> *)loc = 0x8000'f3af; // NOP
+        break;
+      }
+
+      // Just like R_ARM_JUMP24, we need to jump to a thunk if we need to
+      // switch processor mode.
+      i64 val = S + A - P;
+      if (!T || !is_int(val, 25))
+        val = get_thumb_thunk_addr() + A - P;
+      write_thm_b25(loc, val);
+      break;
+    }
+    case R_ARM_MOVW_PREL_NC:
+      write_arm_mov(loc, ((S + A) | T) - P);
+      break;
+    case R_ARM_MOVW_ABS_NC:
+      write_arm_mov(loc, (S + A) | T);
+      break;
+    case R_ARM_THM_MOVW_PREL_NC:
+      write_thm_mov(loc, ((S + A) | T) - P);
+      break;
+    case R_ARM_PREL31:
+      check(S + A - P, -(1LL << 30), 1LL << 30);
+      *(U32<E> *)loc &= 0x8000'0000;
+      *(U32<E> *)loc |= (S + A - P) & 0x7fff'ffff;
+      break;
+    case R_ARM_THM_MOVW_ABS_NC:
+      write_thm_mov(loc, (S + A) | T);
+      break;
+    case R_ARM_MOVT_PREL:
+      write_arm_mov(loc, (S + A - P) >> 16);
+      break;
+    case R_ARM_THM_MOVT_PREL:
+      write_thm_mov(loc, (S + A - P) >> 16);
+      break;
+    case R_ARM_MOVT_ABS:
+      write_arm_mov(loc, (S + A) >> 16);
+      break;
+    case R_ARM_THM_MOVT_ABS:
+      write_thm_mov(loc, (S + A) >> 16);
+      break;
+    case R_ARM_TLS_GD32:
+      *(U32<E> *)loc = sym.get_tlsgd_addr(ctx) + A - P;
+      break;
+    case R_ARM_TLS_LDM32:
+      *(U32<E> *)loc = ctx.got->get_tlsld_addr(ctx) + A - P;
+      break;
+    case R_ARM_TLS_LDO32:
+      *(U32<E> *)loc = S + A - ctx.dtp_addr;
+      break;
+    case R_ARM_TLS_IE32:
+      *(U32<E> *)loc = sym.get_gottp_addr(ctx) + A - P;
+      break;
+    case R_ARM_TLS_LE32:
+      *(U32<E> *)loc = S + A - ctx.tp_addr;
+      break;
+    case R_ARM_TLS_GOTDESC:
+      // ARM32 TLSDESC uses the following code sequence to materialize
+      // a TP-relative address in r0.
+      //
+      //       ldr     r0, .L2
+      //  .L1: bl      foo
+      //           R_ARM_TLS_CALL
+      //  .L2: .word   foo + . - .L1
+      //           R_ARM_TLS_GOTDESC
+      //
+      // We may relax the instructions to the following if its TP-relative
+      // address is known at link-time
+      //
+      //       ldr     r0, .L2
+      //  .L1: nop
+      //       ...
+      //  .L2: .word   foo(tpoff)
+      //
+      // or to the following if the TP-relative address is known at
+      // process startup time.
+      //
+      //       ldr     r0, .L2
+      //  .L1: ldr r0, [pc, r0]
+      //       ...
+      //  .L2: .word   foo(gottpoff) + . - .L1
+      if (sym.has_tlsdesc(ctx)) {
+        // A is odd if the corresponding TLS_CALL is Thumb.
+        *(U32<E> *)loc = sym.get_tlsdesc_addr(ctx) - P + A - ((A & 1) ? 6 : 4);
+      } else if (sym.has_gottp(ctx)) {
+        *(U32<E> *)loc = sym.get_gottp_addr(ctx) - P + A - ((A & 1) ? 5 : 8);
+      } else {
+        *(U32<E> *)loc = S - ctx.tp_addr;
+      }
+      break;
+    case R_ARM_TLS_CALL:
+      if (sym.has_tlsdesc(ctx)) {
+        *(U32<E> *)loc = 0xeb00'0000; // bl 0
+        *(U32<E> *)loc |= bits(get_tlsdesc_trampoline_addr() - P - 8, 25, 2);
+      } else if (sym.has_gottp(ctx)) {
+        *(U32<E> *)loc = 0xe79f'0000; // ldr r0, [pc, r0]
+      } else {
+        *(U32<E> *)loc = 0xe320'f000; // nop
+      }
+      break;
+    case R_ARM_THM_TLS_CALL:
+      if (sym.has_tlsdesc(ctx)) {
+        u64 val = align_to(get_tlsdesc_trampoline_addr() - P - 4, 4);
+        write_thm_b25(loc, val);
+        *(U16<E> *)(loc + 2) &= ~0x1000; // rewrite BL with BLX
+      } else if (sym.has_gottp(ctx)) {
+        // Since `ldr r0, [pc, r0]` is not representable in Thumb,
+        // we use two instructions instead.
+        *(U16<E> *)loc = 0x4478;         // add r0, pc
+        *(U16<E> *)(loc + 2) = 0x6800;   // ldr r0, [r0]
+      } else {
+        *(U32<E> *)loc = 0x8000'f3af;    // nop.w
+      }
+      break;
+    default:
+      Error(ctx) << *this << ": unknown relocation: " << rel;
+    }
+  }
+}
+
+template <>
+void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
+  std::span<const ElfRel<E>> rels = get_rels(ctx);
+
+  for (i64 i = 0; i < rels.size(); i++) {
+    const ElfRel<E> &rel = rels[i];
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
+      continue;
+
+    Symbol<E> &sym = *file.symbols[rel.r_sym];
+    u8 *loc = base + rel.r_offset;
+
+    SectionFragment<E> *frag;
+    i64 frag_addend;
+    std::tie(frag, frag_addend) = get_fragment(ctx, rel);
+
+    u64 S = frag ? frag->get_addr(ctx) : sym.get_addr(ctx);
+    u64 A = frag ? frag_addend : get_addend(*this, rel);
+
+    switch (rel.r_type) {
+    case R_ARM_ABS32:
+      if (std::optional<u64> val = get_tombstone(sym, frag))
+        *(U32<E> *)loc = *val;
+      else
+        *(U32<E> *)loc = S + A;
+      break;
+    case R_ARM_TLS_LDO32:
+      if (std::optional<u64> val = get_tombstone(sym, frag))
+        *(U32<E> *)loc = *val;
+      else
+        *(U32<E> *)loc = S + A - ctx.dtp_addr;
+      break;
+    default:
+      Fatal(ctx) << *this << ": invalid relocation for non-allocated sections: "
+                 << rel;
+      break;
+    }
+  }
+}
+
+template <>
+void InputSection<E>::scan_relocations(Context<E> &ctx) {
+  assert(shdr().sh_flags & SHF_ALLOC);
+  std::span<const ElfRel<E>> rels = get_rels(ctx);
+
+  // Scan relocations
+  for (i64 i = 0; i < rels.size(); i++) {
+    const ElfRel<E> &rel = rels[i];
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
+      continue;
+
+    Symbol<E> &sym = *file.symbols[rel.r_sym];
+
+    if (sym.is_ifunc())
+      sym.flags |= NEEDS_GOT | NEEDS_PLT;
+
+    switch (rel.r_type) {
+    case R_ARM_MOVW_ABS_NC:
+    case R_ARM_THM_MOVW_ABS_NC:
+      scan_absrel(ctx, sym, rel);
+      break;
+    case R_ARM_THM_CALL:
+    case R_ARM_CALL:
+    case R_ARM_JUMP24:
+    case R_ARM_PLT32:
+    case R_ARM_THM_JUMP24:
+      if (sym.is_imported)
+        sym.flags |= NEEDS_PLT;
+      break;
+    case R_ARM_GOT_PREL:
+    case R_ARM_GOT_BREL:
+    case R_ARM_TARGET2:
+      sym.flags |= NEEDS_GOT;
+      break;
+    case R_ARM_MOVT_PREL:
+    case R_ARM_THM_MOVT_PREL:
+    case R_ARM_PREL31:
+      scan_pcrel(ctx, sym, rel);
+      break;
+    case R_ARM_TLS_GD32:
+      sym.flags |= NEEDS_TLSGD;
+      break;
+    case R_ARM_TLS_LDM32:
+      ctx.needs_tlsld = true;
+      break;
+    case R_ARM_TLS_IE32:
+      sym.flags |= NEEDS_GOTTP;
+      break;
+    case R_ARM_TLS_CALL:
+    case R_ARM_THM_TLS_CALL:
+      scan_tlsdesc(ctx, sym);
+      break;
+    case R_ARM_TLS_LE32:
+      check_tlsle(ctx, sym, rel);
+      break;
+    case R_ARM_ABS32:
+    case R_ARM_TARGET1:
+    case R_ARM_MOVT_ABS:
+    case R_ARM_THM_MOVT_ABS:
+    case R_ARM_REL32:
+    case R_ARM_BASE_PREL:
+    case R_ARM_GOTOFF32:
+    case R_ARM_THM_JUMP8:
+    case R_ARM_THM_JUMP11:
+    case R_ARM_THM_JUMP19:
+    case R_ARM_MOVW_PREL_NC:
+    case R_ARM_THM_MOVW_PREL_NC:
+    case R_ARM_TLS_LDO32:
+    case R_ARM_V4BX:
+    case R_ARM_TLS_GOTDESC:
+      break;
+    default:
+      Error(ctx) << *this << ": unknown relocation: " << rel;
+    }
+  }
+}
+
+template <>
+void Thunk<E>::copy_buf(Context<E> &ctx) {
+  // TLS trampoline code. ARM32's TLSDESC is designed so that this
+  // common piece of code is factored out from object files to reduce
+  // output size. Since no one provide, the linker has to synthesize it.
+  constexpr ul32 hdr[] = {
+    0xe08e'0000, // add r0, lr, r0
+    0xe590'1004, // ldr r1, [r0, #4]
+    0xe12f'ff11, // bx  r1
+    0xe320'f000, // nop
+  };
+
+  // This is a range extension and mode switch thunk.
+  // It has two entry points: +0 for Thumb and +4 for ARM.
+  constexpr u8 entry[] = {
+    // .thumb
+    0x78, 0x47,             //    bx   pc  # jumps to 1f
+    0xc0, 0x46,             //    nop
+    // .arm
+    0x00, 0xc0, 0x9f, 0xe5, // 1: ldr  ip, 3f
+    0x0f, 0xf0, 0x8c, 0xe0, // 2: add  pc, ip, pc
+    0x00, 0x00, 0x00, 0x00, // 3: .word sym - 2b
+  };
+
+  static_assert(E::thunk_hdr_size == sizeof(hdr));
+  static_assert(E::thunk_size == sizeof(entry));
+
+  u8 *base = ctx.buf + output_section.shdr.sh_offset + offset;
+  memcpy(base, hdr, sizeof(hdr));
+
+  for (i64 i = 0; i < symbols.size(); i++) {
+    u64 S = symbols[i]->get_addr(ctx);
+    u64 P = get_addr() + offsets[i];
+    u8 *buf = base + offsets[i];
+    memcpy(buf, entry, sizeof(entry));
+    *(U32<E> *)(buf + 12) = S - P - 16;
+  }
+}
+
+template <>
+u64 get_eflags(Context<E> &ctx) {
+  if constexpr (E::is_le)
+    return EF_ARM_EABI_VER5;
+  else
+    return EF_ARM_EABI_VER5 | EF_ARM_BE8;
+}
+
+template <>
+void create_arm_exidx_section<E>(Context<E> &ctx) {
+  for (i64 i = 0; i < ctx.chunks.size(); i++) {
+    OutputSection<E> *osec = ctx.chunks[i]->to_osec();
+
+    if (osec && osec->shdr.sh_type == SHT_ARM_EXIDX) {
+      auto *sec = new Arm32ExidxSection(*osec);
+      ctx.extra.exidx = sec;
+      ctx.chunks[i] = sec;
+      ctx.chunk_pool.emplace_back(sec);
+
+      for (InputSection<E> *isec : osec->members)
+        isec->is_alive = false;
+      break;
+    }
+  }
+}
+
+template <>
+void Arm32ExidxSection<E>::compute_section_size(Context<E> &ctx) {
+  output_section.compute_section_size(ctx);
+  this->shdr.sh_size = output_section.shdr.sh_size + 8; // +8 for sentinel
+}
+
+template <>
+void Arm32ExidxSection<E>::update_shdr(Context<E> &ctx) {
+  // .ARM.exidx's sh_link should be set to the .text section index.
+  // Runtime doesn't care about it, but the binutils's strip command does.
+  if (Chunk<E> *chunk = find_chunk(ctx, ".text"))
+    this->shdr.sh_link = chunk->shndx;
+}
+
+// Returns the end of the text segment
+static u64 get_text_end(Context<E> &ctx) {
+  u64 ret = 0;
+  for (Chunk<E> *chunk : ctx.chunks)
+    if (chunk->shdr.sh_flags & SHF_EXECINSTR)
+      ret = std::max<u64>(ret, chunk->shdr.sh_addr + chunk->shdr.sh_size);
+  return ret;
+}
+
+// ARM executables use an .ARM.exidx section to look up an exception
+// handling record for the current instruction pointer. The table needs
+// to be sorted by their addresses.
+//
+// Other target uses .eh_frame_hdr instead for the same purpose.
+// I don't know why only ARM uses the different mechanism, but it's
+// likely that it's due to some historical reason.
+//
+// This function returns contents of .ARM.exidx.
+template <>
+std::vector<u8> Arm32ExidxSection<E>::get_contents(Context<E> &ctx) {
+  // .ARM.exidx records consists of a signed 31-bit relative address
+  // and a 32-bit value. The relative address indicates the start
+  // address of a function that the record covers. The value is one of
+  // the followings:
+  //
+  // 1. CANTUNWIND indicating that there's no unwinding info for the function,
+  // 2. a compact unwinding record encoded into a 32-bit value, or
+  // 3. a 31-bit relative address which points to a larger record in
+  //    the .ARM.extab section.
+  //
+  // CANTUNWIND is value 1. The most significant bit is set in (2) but
+  // not in (3). So we can distinguished them just by looking at a value.
+  const u32 CANTUNWIND = 1;
+
+  struct Entry {
+    U32<E> addr;
+    U32<E> val;
+  };
+
+  // We reserve one extra slot for the sentinel
+  i64 num_entries = output_section.shdr.sh_size / sizeof(Entry) + 1;
+  std::vector<u8> buf(num_entries * sizeof(Entry));
+  Entry *ent = (Entry *)buf.data();
+
+  // Write section contents to the buffer
+  output_section.shdr.sh_addr = this->shdr.sh_addr;
+  output_section.write_to(ctx, buf.data());
+
+  // Fill in sentinel fields
+  u64 sentinel_addr = this->shdr.sh_addr + sizeof(Entry) * (num_entries - 1);
+  ent[num_entries - 1].addr = get_text_end(ctx) - sentinel_addr;
+  ent[num_entries - 1].val = CANTUNWIND;
+
+  // Entry's addresses are relative to themselves. In order to sort
+  // records by address, we first translate them so that the addresses
+  // are relative to the beginning of the section.
+  auto is_relative = [](u32 val) {
+    return val != CANTUNWIND && !(val & 0x8000'0000);
+  };
+
+  tbb::parallel_for((i64)0, num_entries, [&](i64 i) {
+    i64 offset = sizeof(Entry) * i;
+    ent[i].addr = sign_extend(ent[i].addr, 31) + offset;
+    if (is_relative(ent[i].val))
+      ent[i].val = 0x7fff'ffff & (ent[i].val + offset);
+  });
+
+  ranges::sort(ent, ent + num_entries, {}, &Entry::addr);
+
+  // Remove duplicate adjacent entries. That is, if two adjacent functions
+  // have the same compact unwind info or are both CANTUNWIND, we can
+  // merge them into a single address range.
+  auto tail = ranges::unique(ent, ent + num_entries, {}, &Entry::val);
+  num_entries -= tail.size();
+  buf.resize(num_entries * sizeof(Entry));
+
+  // Make addresses relative to themselves.
+  tbb::parallel_for((i64)0, num_entries, [&](i64 i) {
+    i64 offset = sizeof(Entry) * i;
+    ent[i].addr = 0x7fff'ffff & (ent[i].addr - offset);
+    if (is_relative(ent[i].val))
+      ent[i].val = 0x7fff'ffff & (ent[i].val - offset);
+  });
+
+  return buf;
+}
+
+template <>
+void Arm32ExidxSection<E>::remove_duplicate_entries(Context<E> &ctx) {
+  this->shdr.sh_size = get_contents(ctx).size();
+}
+
+template <>
+void Arm32ExidxSection<E>::copy_buf(Context<E> &ctx) {
+  std::vector<u8> contents = get_contents(ctx);
+  assert(this->shdr.sh_size == contents.size());
+  write_vector(ctx.buf + this->shdr.sh_offset, contents);
+}
+
+// Even though using ARM32 in big-endian mode is very rare, the processor
+// technically supports both little- and big-endian modes. There are two
+// variants of big-endian mode: BE32 and BE8. In BE32, instructions and
+// data are encoded in big-endian. In BE8, instructions are encoded in
+// little-endian, and only data is in big-endian. BE8 is the de facto
+// standard for ARMv6 or later. We support only BE8.
+//
+// A tricky thing is that instructions in an object file are always
+// big-endian if the file is compiled for big-endian mode. In other words,
+// the compiler always emit code in BE32 if -mbig-endian is specified. It
+// is the linker's responsibility to rewrite instructions from big-endian
+// to little-endian for an BE8 output. This function does that.
+//
+// The text section may contain a mix of 32-bit ARM instructions, 16-bit
+// Thumb instructions, and data. We need to distinguish them to swap 4
+// bytes, 2 bytes, or not swap bytes, respectively. The beginning of ARM
+// code, Thumb code, and data is labeled with a mapping symbol of $a, $t,
+// and $d, respectively. We use mapping symbols to determine what to do
+// with the text section.
+//
+// This function is called after we copy the input section contents to the
+// output file. We rewrite instructions in the output buffer in place.
+#if MOLD_ARM32BE
+void arm32be_swap_bytes(Context<E> &ctx) {
+  tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
+    // Collect mapping symbols
+    std::vector<Symbol<E> *> syms;
+
+    for (Symbol<E> *sym : file->get_local_syms())
+      if (InputSection<E> *isec = sym->get_input_section())
+        if (isec->is_alive && (isec->shdr().sh_flags & SHF_EXECINSTR))
+          if (std::string_view x = sym->name();
+              x == "$a" || x.starts_with("$a.") ||
+              x == "$t" || x.starts_with("$t.") ||
+              x == "$d" || x.starts_with("$d."))
+            syms.push_back(sym);
+
+    // Group mapping symbols by input section and sort by address
+    ranges::stable_sort(syms, {}, [](const Symbol<E> *sym) {
+      return std::tuple{(uintptr_t)sym->get_input_section(), sym->value};
+    });
+
+    // Swap bytes
+    for (i64 i = 0; i < syms.size(); i++) {
+      Symbol<E> &sym = *syms[i];
+      if (sym.name().starts_with("$d"))
+        continue;
+
+      InputSection<E> &isec = *sym.get_input_section();
+      u8 *base = ctx.buf + isec.output_section->shdr.sh_offset + isec.offset;
+      u8 *start = base + sym.value;
+      u8 *end;
+
+      if (i + 1 < syms.size() && syms[i + 1]->get_input_section() == &isec)
+        end = base + syms[i + 1]->value;
+      else
+        end = base + isec.sh_size;
+
+      i64 sz = sym.name().starts_with("$a") ? 4 : 2;
+      for (u8 *p = start; p < end; p += sz)
+        std::reverse(p, p + sz);
+    }
+  });
+}
+#endif
+
+} // namespace mold
+
+#endif

src/arch-arm64.cc

@@ -17,11 +17,13 @@
 //
 // https://github.com/ARM-software/abi-aa/blob/main/aaelf64/aaelf64.rst
 
+#if MOLD_ARM64LE || MOLD_ARM64BE
+
 #include "mold.h"
 
-namespace mold::elf {
+namespace mold {
 
-using E = ARM64;
+using E = MOLD_TARGET;
 
 static void write_adrp(u8 *buf, u64 val) {
   *(ul32 *)buf |= (bits(val, 13, 12) << 29) | (bits(val, 32, 14) << 5);
@@ -46,16 +48,16 @@ static u64 page(u64 val) {
 
 template <>
 void write_plt_header(Context<E> &ctx, u8 *buf) {
-  static const ul32 insn[] = {
+  constexpr ul32 insn[] = {
     0xa9bf'7bf0, // stp  x16, x30, [sp,#-16]!
     0x9000'0010, // adrp x16, .got.plt[2]
     0xf940'0211, // ldr  x17, [x16, .got.plt[2]]
     0x9100'0210, // add  x16, x16, .got.plt[2]
     0xd61f'0220, // br   x17
-    0xd503'201f, // nop
-    0xd503'201f, // nop
-    0xd503'201f, // nop
-  };
+    0xd420'7d00, // brk
+    0xd420'7d00, // brk
+    0xd420'7d00, // brk
+ };
 
   u64 gotplt = ctx.gotplt->shdr.sh_addr + 16;
   u64 plt = ctx.plt->shdr.sh_addr;
@@ -68,7 +70,7 @@ void write_plt_header(Context<E> &ctx, u8 *buf) {
 
 template <>
 void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
-  static const ul32 insn[] = {
+  constexpr ul32 insn[] = {
     0x9000'0010, // adrp x16, .got.plt[n]
     0xf940'0211, // ldr  x17, [x16, .got.plt[n]]
     0x9100'0210, // add  x16, x16, .got.plt[n]
@@ -86,14 +88,14 @@ void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
 
 template <>
 void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
-  static const ul32 insn[] = {
+  constexpr ul32 insn[] = {
     0x9000'0010, // adrp x16, GOT[n]
     0xf940'0211, // ldr  x17, [x16, GOT[n]]
     0xd61f'0220, // br   x17
-    0xd503'201f, // nop
+    0xd420'7d00, // brk
   };
 
-  u64 got = sym.get_got_addr(ctx);
+  u64 got = sym.get_got_pltgot_addr(ctx);
   u64 plt = sym.get_plt_addr(ctx);
 
   memcpy(buf, insn, sizeof(insn));
@@ -102,21 +104,21 @@ void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
 }
 
 template <>
-void EhFrameSection<E>::apply_reloc(Context<E> &ctx, const ElfRel<E> &rel,
-                                    u64 offset, u64 val) {
+void EhFrameSection<E>::apply_eh_reloc(Context<E> &ctx, const ElfRel<E> &rel,
+                                       u64 offset, u64 val) {
   u8 *loc = ctx.buf + this->shdr.sh_offset + offset;
 
   switch (rel.r_type) {
   case R_NONE:
     break;
   case R_AARCH64_ABS64:
-    *(ul64 *)loc = val;
+    *(U64<E> *)loc = val;
     break;
   case R_AARCH64_PREL32:
-    *(ul32 *)loc = val - this->shdr.sh_addr - offset;
+    *(U32<E> *)loc = val - this->shdr.sh_addr - offset;
     break;
   case R_AARCH64_PREL64:
-    *(ul64 *)loc = val - this->shdr.sh_addr - offset;
+    *(U64<E> *)loc = val - this->shdr.sh_addr - offset;
     break;
   default:
     Fatal(ctx) << "unsupported relocation in .eh_frame: " << rel;
@@ -145,11 +147,6 @@ template <>
 void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
   std::span<const ElfRel<E>> rels = get_rels(ctx);
 
-  ElfRel<E> *dynrel = nullptr;
-  if (ctx.reldyn)
-    dynrel = (ElfRel<E> *)(ctx.buf + ctx.reldyn->shdr.sh_offset +
-                           file.reldyn_offset + this->reldyn_offset);
-
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
     if (rel.r_type == R_NONE)
@@ -158,22 +155,18 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
     Symbol<E> &sym = *file.symbols[rel.r_sym];
     u8 *loc = base + rel.r_offset;
 
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
     u64 S = sym.get_addr(ctx);
     u64 A = rel.r_addend;
     u64 P = get_addr() + rel.r_offset;
     u64 G = sym.get_got_idx(ctx) * sizeof(Word<E>);
     u64 GOT = ctx.got->shdr.sh_addr;
 
+    auto check = [&](i64 val, i64 lo, i64 hi) {
+      check_range(ctx, i, val, lo, hi);
+    };
+
     switch (rel.r_type) {
     case R_AARCH64_ABS64:
-      apply_dyn_absrel(ctx, sym, rel, loc, S, A, P, dynrel);
       break;
     case R_AARCH64_LDST8_ABS_LO12_NC:
     case R_AARCH64_ADD_ABS_LO12_NC:
@@ -215,6 +208,30 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
     case R_AARCH64_MOVW_UABS_G3:
       *(ul32 *)loc |= bits(S + A, 63, 48) << 5;
       break;
+    case R_AARCH64_MOVW_PREL_G0:
+      check(S + A - P, -(1 << 15), 1 << 15);
+      write_movn_movz(loc, S + A - P);
+      break;
+    case R_AARCH64_MOVW_PREL_G0_NC:
+      *(ul32 *)loc |= bits(S + A - P, 15, 0) << 5;
+      break;
+    case R_AARCH64_MOVW_PREL_G1:
+      check(S + A - P, -(1LL << 31), 1LL << 31);
+      write_movn_movz(loc, (i64)(S + A - P) >> 16);
+      break;
+    case R_AARCH64_MOVW_PREL_G1_NC:
+      *(ul32 *)loc |= bits(S + A - P, 31, 16) << 5;
+      break;
+    case R_AARCH64_MOVW_PREL_G2:
+      check(S + A - P, -(1LL << 47), 1LL << 47);
+      write_movn_movz(loc, (i64)(S + A - P) >> 32);
+      break;
+    case R_AARCH64_MOVW_PREL_G2_NC:
+      *(ul32 *)loc |= bits(S + A - P, 47, 32) << 5;
+      break;
+    case R_AARCH64_MOVW_PREL_G3:
+      *(ul32 *)loc |= bits(S + A - P, 63, 48) << 5;
+      break;
     case R_AARCH64_ADR_GOT_PAGE:
       if (sym.has_got(ctx)) {
         i64 val = page(G + GOT + A) - page(P);
@@ -232,15 +249,18 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
         i++;
       }
       break;
-    case R_AARCH64_ADR_PREL_PG_HI21: {
+    case R_AARCH64_ADR_PREL_PG_HI21:
+    case R_AARCH64_ADR_PREL_PG_HI21_NC: {
       // The ARM64 psABI defines that an `ADRP x0, foo` and `ADD x0, x0,
       // :lo12: foo` instruction pair to materialize a PC-relative address
       // in a register can be relaxed to `NOP` followed by `ADR x0, foo`
       // if foo is in PC ± 1 MiB.
-      if (ctx.arg.relax && i + 1 < rels.size() &&
-          sign_extend(S + A - P - 4, 20) == S + A - P - 4) {
+      if (ctx.arg.relax && sym.is_pcrel_linktime_const(ctx) &&
+          i + 1 < rels.size()) {
+        i64 val = S + A - P - 4;
         const ElfRel<E> &rel2 = rels[i + 1];
-        if (rel2.r_type == R_AARCH64_ADD_ABS_LO12_NC &&
+        if (is_int(val, 21) &&
+            rel2.r_type == R_AARCH64_ADD_ABS_LO12_NC &&
             rel2.r_sym == rel.r_sym &&
             rel2.r_offset == rel.r_offset + 4 &&
             rel2.r_addend == rel.r_addend &&
@@ -251,7 +271,7 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
           if (reg1 == reg2) {
             *(ul32 *)loc = 0xd503'201f;              // nop
             *(ul32 *)(loc + 4) = 0x1000'0000 | reg1; // adr
-            write_adr(loc + 4, S + A - P - 4);
+            write_adr(loc + 4, val);
             i++;
             break;
           }
@@ -259,7 +279,8 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
       }
 
       i64 val = page(S + A) - page(P);
-      check(val, -(1LL << 32), 1LL << 32);
+      if (rel.r_type == R_AARCH64_ADR_PREL_PG_HI21)
+        check(val, -(1LL << 32), 1LL << 32);
       write_adrp(loc, val);
       break;
     }
@@ -277,26 +298,34 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
       }
 
       i64 val = S + A - P;
-      if (val < -(1 << 27) || (1 << 27) <= val)
-        val = get_thunk_addr(i) + A - P;
+      if (!is_int(val, 28))
+        val = sym.get_thunk_addr(ctx, P) + A - P;
       *(ul32 *)loc |= bits(val, 27, 2);
       break;
     }
+    case R_AARCH64_PLT32:
+      check(S + A - P, -(1LL << 31), 1LL << 31);
+      *(U32<E> *)loc = S + A - P;
+      break;
+    case R_AARCH64_GOTPCREL32:
+      check(G + GOT + A - P, -(1LL << 31), 1LL << 31);
+      *(U32<E> *)loc = G + GOT + A - P;
+      break;
     case R_AARCH64_CONDBR19:
     case R_AARCH64_LD_PREL_LO19:
       check(S + A - P, -(1LL << 20), 1LL << 20);
       *(ul32 *)loc |= bits(S + A - P, 20, 2) << 5;
       break;
     case R_AARCH64_PREL16:
-      check(S + A - P, -(1LL << 15), 1LL << 15);
-      *(ul16 *)loc = S + A - P;
+      check(S + A - P, -(1LL << 15), 1LL << 16);
+      *(U16<E> *)loc = S + A - P;
       break;
     case R_AARCH64_PREL32:
       check(S + A - P, -(1LL << 31), 1LL << 32);
-      *(ul32 *)loc = S + A - P;
+      *(U32<E> *)loc = S + A - P;
       break;
     case R_AARCH64_PREL64:
-      *(ul64 *)loc = S + A - P;
+      *(U64<E> *)loc = S + A - P;
       break;
     case R_AARCH64_LD64_GOT_LO12_NC:
       *(ul32 *)loc |= bits(G + GOT + A, 11, 3) << 10;
@@ -363,38 +392,67 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
       *(ul32 *)loc |= bits(sym.get_tlsgd_addr(ctx) + A, 11, 0) << 10;
       break;
     case R_AARCH64_TLSDESC_ADR_PAGE21:
+      // ARM64 TLSDESC uses the following code sequence to materialize
+      // a TP-relative address in x0.
+      //
+      //   adrp    x0, 0
+      //       R_AARCH64_TLSDESC_ADR_PAGE21 foo
+      //   ldr     x1, [x0]
+      //       R_AARCH64_TLSDESC_LD64_LO12  foo
+      //   add     x0, x0, #0
+      //       R_AARCH64_TLSDESC_ADD_LO12   foo
+      //   blr     x1
+      //       R_AARCH64_TLSDESC_CALL       foo
+      //
+      // We may relax the instructions to the following if its TP-relative
+      // address is known at link-time
+      //
+      //   nop
+      //   nop
+      //   movz    x0, :tls_offset_hi:foo, lsl #16
+      //   movk    x0, :tls_offset_lo:foo
+      //
+      // or to the following if the TP-relative address is known at
+      // process startup time.
+      //
+      //   nop
+      //   nop
+      //   adrp    x0, :gottprel:foo
+      //   ldr     x0, [x0, :gottprel_lo12:foo]
       if (sym.has_tlsdesc(ctx)) {
         i64 val = page(sym.get_tlsdesc_addr(ctx) + A) - page(P);
         check(val, -(1LL << 32), 1LL << 32);
         write_adrp(loc, val);
       } else {
-        // adrp x0, 0 -> movz x0, #tls_ofset_hi, lsl #16
-        i64 val = (S + A - ctx.tp_addr);
-        check(val, -(1LL << 32), 1LL << 32);
-        *(ul32 *)loc = 0xd2a0'0000 | (bits(val, 32, 16) << 5);
+        *(ul32 *)loc = 0xd503'201f; // nop
       }
       break;
     case R_AARCH64_TLSDESC_LD64_LO12:
-      if (sym.has_tlsdesc(ctx)) {
+      if (sym.has_tlsdesc(ctx))
         *(ul32 *)loc |= bits(sym.get_tlsdesc_addr(ctx) + A, 11, 3) << 10;
-      } else {
-        // ldr x2, [x0] -> movk x0, #tls_ofset_lo
-        u32 offset_lo = (S + A - ctx.tp_addr) & 0xffff;
-        *(ul32 *)loc = 0xf280'0000 | (offset_lo << 5);
-      }
+      else
+        *(ul32 *)loc = 0xd503'201f; // nop
       break;
     case R_AARCH64_TLSDESC_ADD_LO12:
       if (sym.has_tlsdesc(ctx)) {
         *(ul32 *)loc |= bits(sym.get_tlsdesc_addr(ctx) + A, 11, 0) << 10;
+      } else if (sym.has_gottp(ctx)) {
+        *(ul32 *)loc = 0x9000'0000; // adrp x0, 0
+        write_adrp(loc, page(sym.get_gottp_addr(ctx) + A) - page(P));
       } else {
-        // add x0, x0, #0 -> nop
-        *(ul32 *)loc = 0xd503'201f;
+        *(ul32 *)loc = 0xd2a0'0000; // movz x0, 0, lsl #16
+        *(ul32 *)loc |= bits(S + A - ctx.tp_addr, 32, 16) << 5;
       }
       break;
     case R_AARCH64_TLSDESC_CALL:
-      if (!sym.has_tlsdesc(ctx)) {
-        // blr x2 -> nop
-        *(ul32 *)loc = 0xd503'201f;
+      if (sym.has_tlsdesc(ctx)) {
+        // Do nothing
+      } else if (sym.has_gottp(ctx)) {
+        *(ul32 *)loc = 0xf940'0000; // ldr x0, [x0, 0]
+        *(ul32 *)loc |= bits(sym.get_gottp_addr(ctx) + A, 11, 3) << 10;
+      } else {
+        *(ul32 *)loc = 0xf280'0000; // movk x0, 0
+        *(ul32 *)loc |= bits(S + A - ctx.tp_addr, 15, 0) << 5;
       }
       break;
     default:
@@ -409,25 +467,12 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
     u8 *loc = base + rel.r_offset;
 
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
     SectionFragment<E> *frag;
     i64 frag_addend;
     std::tie(frag, frag_addend) = get_fragment(ctx, rel);
@@ -435,19 +480,21 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
     u64 S = frag ? frag->get_addr(ctx) : sym.get_addr(ctx);
     u64 A = frag ? frag_addend : (i64)rel.r_addend;
 
+    auto check = [&](i64 val, i64 lo, i64 hi) {
+      check_range(ctx, val, i, lo, hi);
+    };
+
     switch (rel.r_type) {
     case R_AARCH64_ABS64:
       if (std::optional<u64> val = get_tombstone(sym, frag))
-        *(ul64 *)loc = *val;
+        *(U64<E> *)loc = *val;
       else
-        *(ul64 *)loc = S + A;
+        *(U64<E> *)loc = S + A;
       break;
-    case R_AARCH64_ABS32: {
-      i64 val = S + A;
-      check(val, 0, 1LL << 32);
-      *(ul32 *)loc = val;
+    case R_AARCH64_ABS32:
+      check(S + A, 0, 1LL << 32);
+      *(U32<E> *)loc = S + A;
       break;
-    }
     default:
       Fatal(ctx) << *this << ": invalid relocation for non-allocated sections: "
                  << rel;
@@ -459,39 +506,31 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 template <>
 void InputSection<E>::scan_relocations(Context<E> &ctx) {
   assert(shdr().sh_flags & SHF_ALLOC);
-
-  this->reldyn_offset = file.num_dynrel * sizeof(ElfRel<E>);
   std::span<const ElfRel<E>> rels = get_rels(ctx);
 
   // Scan relocations
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
     u8 *loc = (u8 *)(contents.data() + rel.r_offset);
 
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
     if (sym.is_ifunc())
       sym.flags |= NEEDS_GOT | NEEDS_PLT;
 
     switch (rel.r_type) {
-    case R_AARCH64_ABS64:
-      scan_dyn_absrel(ctx, sym, rel);
+    case R_AARCH64_MOVW_UABS_G3:
+      scan_absrel(ctx, sym, rel);
       break;
     case R_AARCH64_ADR_GOT_PAGE:
       // An ADR_GOT_PAGE and GOT_LO12_NC relocation pair is used to load a
       // symbol's address from GOT. If the GOT value is a link-time
       // constant, we may be able to rewrite the ADRP+LDR instruction pair
       // with an ADRP+ADD, eliminating a GOT memory load.
-      if (ctx.arg.relax && sym.is_relative() && !sym.is_imported &&
-          !sym.is_ifunc() && i + 1 < rels.size()) {
+      if (ctx.arg.relax && sym.is_pcrel_linktime_const(ctx) &&
+          i + 1 < rels.size()) {
         // ADRP+LDR must be consecutive and use the same register to relax.
         const ElfRel<E> &rel2 = rels[i + 1];
         if (rel2.r_type == R_AARCH64_LD64_GOT_LO12_NC &&
@@ -514,10 +553,12 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
       break;
     case R_AARCH64_LD64_GOT_LO12_NC:
     case R_AARCH64_LD64_GOTPAGE_LO15:
+    case R_AARCH64_GOTPCREL32:
       sym.flags |= NEEDS_GOT;
       break;
     case R_AARCH64_CALL26:
     case R_AARCH64_JUMP26:
+    case R_AARCH64_PLT32:
       if (sym.is_imported)
         sym.flags |= NEEDS_PLT;
       break;
@@ -526,27 +567,21 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
       sym.flags |= NEEDS_GOTTP;
       break;
     case R_AARCH64_ADR_PREL_PG_HI21:
+    case R_AARCH64_ADR_PREL_PG_HI21_NC:
       scan_pcrel(ctx, sym, rel);
       break;
     case R_AARCH64_TLSGD_ADR_PAGE21:
       sym.flags |= NEEDS_TLSGD;
       break;
-    case R_AARCH64_TLSDESC_ADR_PAGE21:
-    case R_AARCH64_TLSDESC_LD64_LO12:
-    case R_AARCH64_TLSDESC_ADD_LO12:
-      if (!relax_tlsdesc(ctx, sym))
-        sym.flags |= NEEDS_TLSDESC;
+    case R_AARCH64_TLSDESC_CALL:
+      scan_tlsdesc(ctx, sym);
       break;
-    case R_AARCH64_TLSLE_MOVW_TPREL_G0:
-    case R_AARCH64_TLSLE_MOVW_TPREL_G0_NC:
-    case R_AARCH64_TLSLE_MOVW_TPREL_G1:
-    case R_AARCH64_TLSLE_MOVW_TPREL_G1_NC:
     case R_AARCH64_TLSLE_MOVW_TPREL_G2:
-    case R_AARCH64_TLSLE_ADD_TPREL_HI12:
     case R_AARCH64_TLSLE_ADD_TPREL_LO12:
     case R_AARCH64_TLSLE_ADD_TPREL_LO12_NC:
       check_tlsle(ctx, sym, rel);
       break;
+    case R_AARCH64_ABS64:
     case R_AARCH64_ADD_ABS_LO12_NC:
     case R_AARCH64_ADR_PREL_LO21:
     case R_AARCH64_CONDBR19:
@@ -562,12 +597,25 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
     case R_AARCH64_MOVW_UABS_G1_NC:
     case R_AARCH64_MOVW_UABS_G2:
     case R_AARCH64_MOVW_UABS_G2_NC:
-    case R_AARCH64_MOVW_UABS_G3:
+    case R_AARCH64_MOVW_PREL_G0:
+    case R_AARCH64_MOVW_PREL_G0_NC:
+    case R_AARCH64_MOVW_PREL_G1:
+    case R_AARCH64_MOVW_PREL_G1_NC:
+    case R_AARCH64_MOVW_PREL_G2:
+    case R_AARCH64_MOVW_PREL_G2_NC:
+    case R_AARCH64_MOVW_PREL_G3:
     case R_AARCH64_PREL16:
     case R_AARCH64_PREL32:
     case R_AARCH64_PREL64:
     case R_AARCH64_TLSGD_ADD_LO12_NC:
-    case R_AARCH64_TLSDESC_CALL:
+    case R_AARCH64_TLSLE_MOVW_TPREL_G0:
+    case R_AARCH64_TLSLE_MOVW_TPREL_G0_NC:
+    case R_AARCH64_TLSLE_MOVW_TPREL_G1:
+    case R_AARCH64_TLSLE_MOVW_TPREL_G1_NC:
+    case R_AARCH64_TLSLE_ADD_TPREL_HI12:
+    case R_AARCH64_TLSDESC_ADR_PAGE21:
+    case R_AARCH64_TLSDESC_LD64_LO12:
+    case R_AARCH64_TLSDESC_ADD_LO12:
       break;
     default:
       Error(ctx) << *this << ": unknown relocation: " << rel;
@@ -575,27 +623,81 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
   }
 }
 
+// The size of a thunk entry varies on ARM64 depending on the distance to
+// the branch target. This function computes the size of each thunk entry.
 template <>
-void RangeExtensionThunk<E>::copy_buf(Context<E> &ctx) {
-  u8 *buf = ctx.buf + output_section.shdr.sh_offset + offset;
+void Thunk<E>::shrink_size(Context<E> &ctx) {
+  offsets.clear();
+  offsets.push_back(0);
+  i64 off = 0;
 
-  static const ul32 data[] = {
-    0x9000'0010, // adrp x16, 0   # R_AARCH64_ADR_PREL_PG_HI21
-    0x9100'0210, // add  x16, x16 # R_AARCH64_ADD_ABS_LO12_NC
-    0xd61f'0200, // br   x16
+  // The distance between S and P is only reduced by shrink_size(), but
+  // page(S) – page(P) may still increase by one page due to address
+  // changes, so we add a safety margin.
+  //
+  // For example, page(0x1200) – page(0x1000) is 0, whereas
+  // page(0x1100) – page(0xfff) is 0x1000, even though the latter
+  // distance is shorter than the former.
+  auto is_small = [](i64 prel) {
+    return is_int(prel + 0x1000, 33) && is_int(prel - 0x1000, 33);
   };
 
-  static_assert(E::thunk_size == sizeof(data));
-
-  for (i64 i = 0; i < symbols.size(); i++) {
-    u64 S = symbols[i]->get_addr(ctx);
-    u64 P = output_section.shdr.sh_addr + offset + i * E::thunk_size;
-
-    u8 *loc = buf + i * E::thunk_size;
-    memcpy(loc , data, sizeof(data));
-    write_adrp(loc, page(S) - page(P));
-    *(ul32 *)(loc + 4) |= bits(S, 11, 0) << 10;
+  for (Symbol<E> *sym : symbols) {
+    u64 S = sym->get_addr(ctx);
+    u64 P = get_addr() + off;
+    i64 prel = page(S) - page(P);
+    off += is_small(prel) ? 16 : 32;
+    offsets.push_back(off);
   }
 }
 
-} // namespace mold::elf
+template <>
+void Thunk<E>::copy_buf(Context<E> &ctx) {
+  // Short thunk with a 33 bit displacement
+  constexpr ul32 insn1[] = {
+    0x9000'0010, // adrp x16, 0
+    0x9100'0210, // add  x16, x16
+    0xd61f'0200, // br   x16
+    0xd420'7d00, // brk
+  };
+
+  // Long thunk with a 64 bit displacement
+  constexpr ul32 insn2[] = {
+    0x1000'0010, // adr  x16, 0
+    0xd2a0'0011, // movz x17, 0, lsl #16
+    0xf2c0'0011, // movk x17, 0, lsl #32
+    0xf2e0'0011, // movk x17, 0, lsl #48
+    0x8b11'0210, // add  x16, x16, x17
+    0xd61f'0200, // br   x16
+    0xd420'7d00, // brk
+    0xd420'7d00, // brk
+  };
+
+  u8 *base = ctx.buf + output_section.shdr.sh_offset + offset;
+
+  for (i64 i = 0; i < symbols.size(); i++) {
+    u64 S = symbols[i]->get_addr(ctx);
+    u64 P = get_addr() + offsets[i];
+    u8 *buf = base + offsets[i];
+
+    if (offsets[i + 1] - offsets[i] == 16) {
+      i64 prel = page(S) - page(P);
+      assert(is_int(prel, 33));
+      memcpy(buf, insn1, sizeof(insn1));
+      write_adrp(buf, prel);
+      *(ul32 *)(buf + 4) |= bits(S, 11, 0) << 10;
+    } else {
+      memcpy(buf, insn2, sizeof(insn2));
+      write_adr(buf, bits(S - P, 15, 0));
+      *(ul32 *)(buf + 4) |= bits(S - P, 31, 16) << 5;
+      *(ul32 *)(buf + 8) |= bits(S - P, 47, 32) << 5;
+      *(ul32 *)(buf + 12) |= bits(S - P, 63, 48) << 5;
+    }
+  }
+}
+
+template class Thunk<E>;
+
+} // namespace mold
+
+#endif

src/arch-i386.cc

@@ -33,9 +33,11 @@
 //
 // https://github.com/rui314/psabi/blob/main/i386.pdf
 
+#if MOLD_I386
+
 #include "mold.h"
 
-namespace mold::elf {
+namespace mold {
 
 using E = I386;
 
@@ -44,10 +46,10 @@ i64 get_addend(u8 *loc, const ElfRel<E> &rel) {
   switch (rel.r_type) {
   case R_386_8:
   case R_386_PC8:
-    return *loc;
+    return *(i8 *)loc;
   case R_386_16:
   case R_386_PC16:
-    return *(ul16 *)loc;
+    return *(il16 *)loc;
   case R_386_32:
   case R_386_PC32:
   case R_386_GOT32:
@@ -63,7 +65,7 @@ i64 get_addend(u8 *loc, const ElfRel<E> &rel) {
   case R_386_TLS_LDO_32:
   case R_386_SIZE32:
   case R_386_TLS_GOTDESC:
-    return *(ul32 *)loc;
+    return *(il32 *)loc;
   default:
     return 0;
   }
@@ -108,25 +110,24 @@ template <>
 void write_plt_header(Context<E> &ctx, u8 *buf) {
   if (ctx.arg.pic) {
     static const u8 insn[] = {
-      0xf3, 0x0f, 0x1e, 0xfb, // endbr32
       0x51,                   // push   %ecx
       0x8d, 0x8b, 0, 0, 0, 0, // lea    GOTPLT+4(%ebx), %ecx
       0xff, 0x31,             // push   (%ecx)
       0xff, 0x61, 0x04,       // jmp    *0x4(%ecx)
+      0xcc, 0xcc, 0xcc, 0xcc, // (padding)
     };
     memcpy(buf, insn, sizeof(insn));
-    *(ul32 *)(buf + 7) = ctx.gotplt->shdr.sh_addr - ctx.got->shdr.sh_addr + 4;
+    *(ul32 *)(buf + 3) = ctx.gotplt->shdr.sh_addr - ctx.got->shdr.sh_addr + 4;
   } else {
     static const u8 insn[] = {
-      0xf3, 0x0f, 0x1e, 0xfb, // endbr32
-      0x51,                   // push   %ecx
-      0xb9, 0, 0, 0, 0,       // mov    GOTPLT+4, %ecx
-      0xff, 0x31,             // push   (%ecx)
-      0xff, 0x61, 0x04,       // jmp    *0x4(%ecx)
-      0xcc,                   // (padding)
+      0x51,                         // push   %ecx
+      0xb9, 0, 0, 0, 0,             // mov    GOTPLT+4, %ecx
+      0xff, 0x31,                   // push   (%ecx)
+      0xff, 0x61, 0x04,             // jmp    *0x4(%ecx)
+      0xcc, 0xcc, 0xcc, 0xcc, 0xcc, // (padding)
     };
     memcpy(buf, insn, sizeof(insn));
-    *(ul32 *)(buf + 6) = ctx.gotplt->shdr.sh_addr + 4;
+    *(ul32 *)(buf + 2) = ctx.gotplt->shdr.sh_addr + 4;
   }
 }
 
@@ -134,24 +135,22 @@ template <>
 void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
   if (ctx.arg.pic) {
     static const u8 insn[] = {
-      0xf3, 0x0f, 0x1e, 0xfb, // endbr32
-      0xb9, 0, 0, 0, 0,       // mov $reloc_offset, %ecx
-      0xff, 0xa3, 0, 0, 0, 0, // jmp *foo@GOT(%ebx)
-      0xcc,                   // (padding)
+      0xb9, 0, 0, 0, 0,             // mov $reloc_offset, %ecx
+      0xff, 0xa3, 0, 0, 0, 0,       // jmp *foo@GOT(%ebx)
+      0xcc, 0xcc, 0xcc, 0xcc, 0xcc, // (padding)
     };
     memcpy(buf, insn, sizeof(insn));
-    *(ul32 *)(buf + 5) = sym.get_plt_idx(ctx) * sizeof(ElfRel<E>);
-    *(ul32 *)(buf + 11) = sym.get_gotplt_addr(ctx) - ctx.got->shdr.sh_addr;
+    *(ul32 *)(buf + 1) = sym.get_plt_idx(ctx) * sizeof(ElfRel<E>);
+    *(ul32 *)(buf + 7) = sym.get_gotplt_addr(ctx) - ctx.got->shdr.sh_addr;
   } else {
     static const u8 insn[] = {
-      0xf3, 0x0f, 0x1e, 0xfb, // endbr32
-      0xb9, 0, 0, 0, 0,       // mov $reloc_offset, %ecx
-      0xff, 0x25, 0, 0, 0, 0, // jmp *foo@GOT
-      0xcc,                   // (padding)
+      0xb9, 0, 0, 0, 0,             // mov $reloc_offset, %ecx
+      0xff, 0x25, 0, 0, 0, 0,       // jmp *foo@GOT
+      0xcc, 0xcc, 0xcc, 0xcc, 0xcc, // (padding)
     };
     memcpy(buf, insn, sizeof(insn));
-    *(ul32 *)(buf + 5) = sym.get_plt_idx(ctx) * sizeof(ElfRel<E>);
-    *(ul32 *)(buf + 11) = sym.get_gotplt_addr(ctx);
+    *(ul32 *)(buf + 1) = sym.get_plt_idx(ctx) * sizeof(ElfRel<E>);
+    *(ul32 *)(buf + 7) = sym.get_gotplt_addr(ctx);
   }
 }
 
@@ -159,26 +158,24 @@ template <>
 void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
   if (ctx.arg.pic) {
     static const u8 insn[] = {
-      0xf3, 0x0f, 0x1e, 0xfb,             // endbr32
-      0xff, 0xa3, 0, 0, 0, 0,             // jmp *foo@GOT(%ebx)
-      0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, // (padding)
+      0xff, 0xa3, 0, 0, 0, 0, // jmp *foo@GOT(%ebx)
+      0xcc, 0xcc,             // (padding)
     };
     memcpy(buf, insn, sizeof(insn));
-    *(ul32 *)(buf + 6) = sym.get_got_addr(ctx) - ctx.got->shdr.sh_addr;
+    *(ul32 *)(buf + 2) = sym.get_got_pltgot_addr(ctx) - ctx.got->shdr.sh_addr;
   } else {
     static const u8 insn[] = {
-      0xf3, 0x0f, 0x1e, 0xfb,             // endbr32
-      0xff, 0x25, 0, 0, 0, 0,             // jmp *foo@GOT
-      0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, // (padding)
+      0xff, 0x25, 0, 0, 0, 0, // jmp *foo@GOT
+      0xcc, 0xcc,             // (padding)
     };
     memcpy(buf, insn, sizeof(insn));
-    *(ul32 *)(buf + 6) = sym.get_got_addr(ctx);
+    *(ul32 *)(buf + 2) = sym.get_got_pltgot_addr(ctx);
   }
 }
 
 template <>
-void EhFrameSection<E>::apply_reloc(Context<E> &ctx, const ElfRel<E> &rel,
-                                    u64 offset, u64 val) {
+void EhFrameSection<E>::apply_eh_reloc(Context<E> &ctx, const ElfRel<E> &rel,
+                                       u64 offset, u64 val) {
   u8 *loc = ctx.buf + this->shdr.sh_offset + offset;
 
   switch (rel.r_type) {
@@ -226,7 +223,7 @@ static void relax_gd_to_le(u8 *loc, ElfRel<E> rel, u64 val) {
 }
 
 // Relax LD to LE
-static void relax_ld_to_le(u8 *loc, ElfRel<E> rel, u64 val) {
+static void relax_ld_to_le(u8 *loc, ElfRel<E> rel, u64 tls_size) {
   switch (rel.r_type) {
   case R_386_PLT32:
   case R_386_PC32: {
@@ -235,18 +232,17 @@ static void relax_ld_to_le(u8 *loc, ElfRel<E> rel, u64 val) {
       0x2d, 0, 0, 0, 0,       // sub $tls_size, %eax
     };
     memcpy(loc - 2, insn, sizeof(insn));
-    *(ul32 *)(loc + 5) = val;
+    *(ul32 *)(loc + 5) = tls_size;
     break;
   }
   case R_386_GOT32:
   case R_386_GOT32X: {
     static const u8 insn[] = {
       0x65, 0xa1, 0, 0, 0, 0, // mov %gs:0, %eax
-      0x2d, 0, 0, 0, 0,       // sub $tls_size, %eax
-      0x90,                   // nop
+      0x81, 0xe8, 0, 0, 0, 0, // sub $tls_size, %eax
     };
     memcpy(loc - 2, insn, sizeof(insn));
-    *(ul32 *)(loc + 5) = val;
+    *(ul32 *)(loc + 6) = tls_size;
     break;
   }
   default:
@@ -254,15 +250,38 @@ static void relax_ld_to_le(u8 *loc, ElfRel<E> rel, u64 val) {
   }
 }
 
+static u32 relax_tlsdesc_to_ie(u8 *loc) {
+  switch ((loc[0] << 8) | loc[1]) {
+  case 0x8d83: return 0x8b83; // lea 0(%ebx), %eax -> mov 0(%ebx), %eax
+  case 0x8d9b: return 0x8b9b; // lea 0(%ebx), %ebx -> mov 0(%ebx), %ebx
+  case 0x8d8b: return 0x8b8b; // lea 0(%ebx), %ecx -> mov 0(%ebx), %ecx
+  case 0x8d93: return 0x8b93; // lea 0(%ebx), %edx -> mov 0(%ebx), %edx
+  case 0x8db3: return 0x8bb3; // lea 0(%ebx), %esi -> mov 0(%ebx), %esi
+  case 0x8dbb: return 0x8bbb; // lea 0(%ebx), %edi -> mov 0(%ebx), %edi
+  case 0x8da3: return 0x8ba3; // lea 0(%ebx), %esp -> mov 0(%ebx), %esp
+  case 0x8dab: return 0x8bab; // lea 0(%ebx), %ebp -> mov 0(%ebx), %ebp
+  }
+  return 0;
+}
+
+static u32 relax_tlsdesc_to_le(u8 *loc) {
+  switch ((loc[0] << 8) | loc[1]) {
+  case 0x8d83: return 0x90b8; // lea 0(%ebx), %eax -> mov $0, %eax
+  case 0x8d9b: return 0x90bb; // lea 0(%ebx), %ebx -> mov $0, %ebx
+  case 0x8d8b: return 0x90b9; // lea 0(%ebx), %ecx -> mov $0, %ecx
+  case 0x8d93: return 0x90ba; // lea 0(%ebx), %edx -> mov $0, %edx
+  case 0x8db3: return 0x90be; // lea 0(%ebx), %esi -> mov $0, %esi
+  case 0x8dbb: return 0x90bf; // lea 0(%ebx), %edi -> mov $0, %edi
+  case 0x8da3: return 0x90bc; // lea 0(%ebx), %esp -> mov $0, %esp
+  case 0x8dab: return 0x90bd; // lea 0(%ebx), %ebp -> mov $0, %ebp
+  }
+  return 0;
+}
+
 template <>
 void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
   std::span<const ElfRel<E>> rels = get_rels(ctx);
 
-  ElfRel<E> *dynrel = nullptr;
-  if (ctx.reldyn)
-    dynrel = (ElfRel<E> *)(ctx.buf + ctx.reldyn->shdr.sh_offset +
-                           file.reldyn_offset + this->reldyn_offset);
-
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
     if (rel.r_type == R_NONE)
@@ -271,19 +290,16 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
     Symbol<E> &sym = *file.symbols[rel.r_sym];
     u8 *loc = base + rel.r_offset;
 
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
     u64 S = sym.get_addr(ctx);
     u64 A = get_addend(*this, rel);
     u64 P = get_addr() + rel.r_offset;
     u64 G = sym.get_got_idx(ctx) * sizeof(Word<E>);
     u64 GOT = ctx.got->shdr.sh_addr;
 
+    auto check = [&](i64 val, i64 lo, i64 hi) {
+      check_range(ctx, i, val, lo, hi);
+    };
+
     switch (rel.r_type) {
     case R_386_8:
       check(S + A, 0, 1 << 8);
@@ -294,7 +310,6 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
       *(ul16 *)loc = S + A;
       break;
     case R_386_32:
-      apply_dyn_absrel(ctx, sym, rel, loc, S, A, P, dynrel);
       break;
     case R_386_PC8:
       check(S + A - P, -(1 << 7), 1 << 7);
@@ -338,20 +353,16 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
       *(ul32 *)loc = sym.get_gottp_addr(ctx) + A;
       break;
     case R_386_TLS_GD:
-      if (sym.has_tlsgd(ctx)) {
+      if (sym.has_tlsgd(ctx))
         *(ul32 *)loc = sym.get_tlsgd_addr(ctx) + A - GOT;
-      } else {
-        relax_gd_to_le(loc, rels[i + 1], S - ctx.tp_addr);
-        i++;
-      }
+      else
+        relax_gd_to_le(loc, rels[++i], S - ctx.tp_addr);
       break;
     case R_386_TLS_LDM:
-      if (ctx.got->has_tlsld(ctx)) {
+      if (ctx.got->has_tlsld(ctx))
         *(ul32 *)loc = ctx.got->get_tlsld_addr(ctx) + A - GOT;
-      } else {
-        relax_ld_to_le(loc, rels[i + 1], ctx.tp_addr - ctx.tls_begin);
-        i++;
-      }
+      else
+        relax_ld_to_le(loc, rels[++i], ctx.tp_addr - ctx.tls_begin);
       break;
     case R_386_TLS_LDO_32:
       *(ul32 *)loc = S + A - ctx.dtp_addr;
@@ -360,13 +371,53 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
       *(ul32 *)loc = sym.esym().st_size + A;
       break;
     case R_386_TLS_GOTDESC:
+      // i386 TLSDESC uses the following code sequence to materialize
+      // a TP-relative address in %eax.
+      //
+      //   lea    0(%ebx), %eax
+      //       R_386_TLS_GOTDESC   foo
+      //   call   *(%eax)
+      //       R_386_TLS_DESC_CALL foo
+      //
+      // We may relax the instructions to the following if its TP-relative
+      // address is known at link-time
+      //
+      //   mov     $foo@TPOFF, %eax
+      //   nop
+      //
+      // or to the following if the TP-relative address is known at
+      // process startup time.
+      //
+      //   mov     foo@GOTTPOFF(%ebx), %eax
+      //   nop
+      //
+      // We allow the following alternative code sequence too because
+      // LLVM emits such code.
+      //
+      //   lea    0(%ebx), %reg
+      //       R_386_TLS_GOTDESC   foo
+      //   mov    %reg, %eax
+      //   call   *(%eax)
+      //       R_386_TLS_DESC_CALL foo
+      //
+      // Note that the compiler always uses the local-exec TLS model
+      // for -fno-pic, so TLSDESC code is always PIC (i.e. uses %ebx to
+      // store the address of GOT.)
       if (sym.has_tlsdesc(ctx)) {
         *(ul32 *)loc = sym.get_tlsdesc_addr(ctx) + A - GOT;
+      } else if (sym.has_gottp(ctx)) {
+        u32 insn = relax_tlsdesc_to_ie(loc - 2);
+        if (!insn)
+          Fatal(ctx) << *this << ": illegal instruction sequence for TLSDESC";
+        loc[-2] = insn >> 8;
+        loc[-1] = insn;
+        *(ul32 *)loc = sym.get_gottp_addr(ctx) + A - GOT;
       } else {
-        static const u8 insn[] = {
-          0x8d, 0x05, 0, 0, 0, 0, // lea 0, %eax
-        };
-        memcpy(loc - 2, insn, sizeof(insn));
+        u32 insn = relax_tlsdesc_to_le(loc - 2);
+        if (!insn)
+          Fatal(ctx) << *this << ": illegal instruction sequence for TLSDESC";
+        loc[-2] = insn >> 8;
+        loc[-1] = insn;
         *(ul32 *)loc = S + A - ctx.tp_addr;
       }
       break;
@@ -389,25 +440,12 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
     u8 *loc = base + rel.r_offset;
 
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
     SectionFragment<E> *frag;
     i64 frag_addend;
     std::tie(frag, frag_addend) = get_fragment(ctx, rel);
@@ -416,6 +454,10 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
     u64 A = frag ? frag_addend : get_addend(*this, rel);
     u64 GOT = ctx.got->shdr.sh_addr;
 
+    auto check = [&](i64 val, i64 lo, i64 hi) {
+      check_range(ctx, val, i, lo, hi);
+    };
+
     switch (rel.r_type) {
     case R_386_8:
       check(S + A, 0, 1 << 8);
@@ -466,36 +508,35 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 template <>
 void InputSection<E>::scan_relocations(Context<E> &ctx) {
   assert(shdr().sh_flags & SHF_ALLOC);
-
-  this->reldyn_offset = file.num_dynrel * sizeof(ElfRel<E>);
   std::span<const ElfRel<E>> rels = get_rels(ctx);
 
   // Scan relocations
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
     u8 *loc = (u8 *)(contents.data() + rel.r_offset);
 
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
     if (sym.is_ifunc())
       sym.flags |= NEEDS_GOT | NEEDS_PLT;
 
+    if (rel.r_type == R_386_TLS_GD || rel.r_type == R_386_TLS_LDM) {
+      if (i + 1 == rels.size())
+        Fatal(ctx) << *this << ": " << rel << " must be followed by PLT or GOT32";
+
+      if (u32 ty = rels[i + 1].r_type;
+          ty != R_386_PLT32 && ty != R_386_PC32 &&
+          ty != R_386_GOT32 && ty != R_386_GOT32X)
+        Fatal(ctx) << *this << ": " << rel << " must be followed by PLT or GOT32";
+    }
+
     switch (rel.r_type) {
     case R_386_8:
     case R_386_16:
       scan_absrel(ctx, sym, rel);
       break;
-    case R_386_32:
-      scan_dyn_absrel(ctx, sym, rel);
-      break;
     case R_386_PC8:
     case R_386_PC16:
     case R_386_PC32:
@@ -505,15 +546,15 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
     case R_386_GOTPC:
       sym.flags |= NEEDS_GOT;
       break;
-    case R_386_GOT32X: {
-      // We always want to relax GOT32X because static PIE doesn't
-      // work without it.
-      bool do_relax = !sym.is_imported && sym.is_relative() &&
-                      relax_got32x(loc - 2);
-      if (!do_relax)
+    case R_386_GOT32X:
+      // We always want to relax GOT32X even if --no-relax is given
+      // because static PIE doesn't work without it.
+      if (sym.is_pcrel_linktime_const(ctx) && relax_got32x(loc - 2)) {
+        // Do nothing
+      } else {
         sym.flags |= NEEDS_GOT;
+      }
       break;
-    }
     case R_386_PLT32:
       if (sym.is_imported)
         sym.flags |= NEEDS_PLT;
@@ -523,45 +564,28 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
       sym.flags |= NEEDS_GOTTP;
       break;
     case R_386_TLS_GD:
-      if (i + 1 == rels.size())
-        Fatal(ctx) << *this << ": TLS_GD reloc must be followed by PLT or GOT32";
-
-      if (u32 ty = rels[i + 1].r_type;
-          ty != R_386_PLT32 && ty != R_386_PC32 &&
-          ty != R_386_GOT32 && ty != R_386_GOT32X)
-        Fatal(ctx) << *this << ": TLS_GD reloc must be followed by PLT or GOT32";
-
       // We always relax if -static because libc.a doesn't contain
       // __tls_get_addr().
-      if (ctx.arg.is_static ||
-          (ctx.arg.relax && !ctx.arg.shared && !sym.is_imported))
+      if (ctx.arg.static_ || (ctx.arg.relax && sym.is_tprel_linktime_const(ctx)))
         i++;
       else
         sym.flags |= NEEDS_TLSGD;
       break;
     case R_386_TLS_LDM:
-      if (i + 1 == rels.size())
-        Fatal(ctx) << *this << ": TLS_LDM reloc must be followed by PLT or GOT32";
-
-      if (u32 ty = rels[i + 1].r_type;
-          ty != R_386_PLT32 && ty != R_386_PC32 &&
-          ty != R_386_GOT32 && ty != R_386_GOT32X)
-        Fatal(ctx) << *this << ": TLS_LDM reloc must be followed by PLT or GOT32";
-
       // We always relax if -static because libc.a doesn't contain
       // __tls_get_addr().
-      if (ctx.arg.is_static || (ctx.arg.relax && !ctx.arg.shared))
+      if (ctx.arg.static_ || (ctx.arg.relax && !ctx.arg.shared))
         i++;
       else
         ctx.needs_tlsld = true;
       break;
     case R_386_TLS_GOTDESC:
-      if (!relax_tlsdesc(ctx, sym))
-        sym.flags |= NEEDS_TLSDESC;
+      scan_tlsdesc(ctx, sym);
       break;
     case R_386_TLS_LE:
       check_tlsle(ctx, sym, rel);
       break;
+    case R_386_32:
     case R_386_GOTOFF:
     case R_386_TLS_LDO_32:
     case R_386_SIZE32:
@@ -573,4 +597,6 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
   }
 }
 
-} // namespace mold::elf
+} // namespace mold
+
+#endif

src/arch-m68k.cc

@@ -1,10 +1,10 @@
 // This file contains code for the Motorola 68000 series microprocessors,
 // which is often abbreviated as m68k. Running a Unix-like system on a
-// m68k-based machine today is probably a retro-computing hobby activity,
-// but the processor was a popular choice to build Unix computers during
-// '80s. Early Sun workstations for example used m68k. Macintosh until
-// 1994 were based on m68k as well until they switched to PowerPC (and
-// then to x86 and to ARM.)
+// m68k-based machine today is a retro-computing hobby activity, but the
+// processor was a popular choice to build Unix computers during '80s.
+// Early Sun workstations for example used m68k. Macintosh until 1994 were
+// based on m68k as well until they switched to PowerPC (and then to x86
+// and to ARM.)
 //
 // From the linker's point of view, it is not hard to support m68k. It's
 // just a 32-bit big-endian CISC ISA. Compared to comtemporary i386,
@@ -14,9 +14,11 @@
 //
 // https://github.com/rui314/psabi/blob/main/m68k.pdf
 
+#if MOLD_M68K
+
 #include "mold.h"
 
-namespace mold::elf {
+namespace mold {
 
 using E = M68K;
 
@@ -52,12 +54,12 @@ void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
   };
 
   memcpy(buf, insn, sizeof(insn));
-  *(ub32 *)(buf + 4) = sym.get_got_addr(ctx) - sym.get_plt_addr(ctx) - 2;
+  *(ub32 *)(buf + 4) = sym.get_got_pltgot_addr(ctx) - sym.get_plt_addr(ctx) - 2;
 }
 
 template <>
-void EhFrameSection<E>::apply_reloc(Context<E> &ctx, const ElfRel<E> &rel,
-                                    u64 offset, u64 val) {
+void EhFrameSection<E>::apply_eh_reloc(Context<E> &ctx, const ElfRel<E> &rel,
+                                       u64 offset, u64 val) {
   u8 *loc = ctx.buf + this->shdr.sh_offset + offset;
 
   switch (rel.r_type) {
@@ -78,11 +80,6 @@ template <>
 void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
   std::span<const ElfRel<E>> rels = get_rels(ctx);
 
-  ElfRel<E> *dynrel = nullptr;
-  if (ctx.reldyn)
-    dynrel = (ElfRel<E> *)(ctx.buf + ctx.reldyn->shdr.sh_offset +
-                           file.reldyn_offset + this->reldyn_offset);
-
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
     if (rel.r_type == R_NONE)
@@ -91,11 +88,14 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
     Symbol<E> &sym = *file.symbols[rel.r_sym];
     u8 *loc = base + rel.r_offset;
 
+    u64 S = sym.get_addr(ctx);
+    u64 A = rel.r_addend;
+    u64 P = get_addr() + rel.r_offset;
+    u64 G = sym.get_got_idx(ctx) * sizeof(Word<E>);
+    u64 GOT = ctx.got->shdr.sh_addr;
+
     auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
+      check_range(ctx, i, val, lo, hi);
     };
 
     auto write16 = [&](u64 val) {
@@ -118,15 +118,8 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
       *loc = val;
     };
 
-    u64 S = sym.get_addr(ctx);
-    u64 A = rel.r_addend;
-    u64 P = get_addr() + rel.r_offset;
-    u64 G = sym.get_got_idx(ctx) * sizeof(Word<E>);
-    u64 GOT = ctx.got->shdr.sh_addr;
-
     switch (rel.r_type) {
     case R_68K_32:
-      apply_dyn_absrel(ctx, sym, rel, loc, S, A, P, dynrel);
       break;
     case R_68K_16:
       write16(S + A);
@@ -221,18 +214,12 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
     u8 *loc = base + rel.r_offset;
 
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
     SectionFragment<E> *frag;
     i64 frag_addend;
     std::tie(frag, frag_addend) = get_fragment(ctx, rel);
@@ -257,30 +244,19 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 template <>
 void InputSection<E>::scan_relocations(Context<E> &ctx) {
   assert(shdr().sh_flags & SHF_ALLOC);
-
-  this->reldyn_offset = file.num_dynrel * sizeof(ElfRel<E>);
   std::span<const ElfRel<E>> rels = get_rels(ctx);
 
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
 
     if (sym.is_ifunc())
       Error(ctx) << sym << ": GNU ifunc symbol is not supported on m68k";
 
     switch (rel.r_type) {
-    case R_68K_32:
-      scan_dyn_absrel(ctx, sym, rel);
-      break;
     case R_68K_16:
     case R_68K_8:
       scan_absrel(ctx, sym, rel);
@@ -324,6 +300,7 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
     case R_68K_TLS_LE8:
       check_tlsle(ctx, sym, rel);
       break;
+    case R_68K_32:
     case R_68K_TLS_LDO32:
     case R_68K_TLS_LDO16:
     case R_68K_TLS_LDO8:
@@ -334,4 +311,6 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
   }
 }
 
-} // namespace mold::elf
+} // namespace mold
+
+#endif

src/arch-ppc32.cc

@@ -40,9 +40,11 @@
 //
 // https://github.com/rui314/psabi/blob/main/ppc32.pdf
 
+#if MOLD_PPC32
+
 #include "mold.h"
 
-namespace mold::elf {
+namespace mold {
 
 using E = PPC32;
 
@@ -54,7 +56,7 @@ static u64 higha(u64 x) { return ((x + 0x8000) >> 16) & 0xffff; }
 
 template <>
 void write_plt_header(Context<E> &ctx, u8 *buf) {
-  static const ub32 insn[] = {
+  constexpr ub32 insn[] = {
     // Get the address of this PLT section
     0x7c08'02a6, //    mflr    r0
     0x429f'0005, //    bcl     20, 31, 4
@@ -88,7 +90,7 @@ void write_plt_header(Context<E> &ctx, u8 *buf) {
   loc[5] |= lo(ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr + 4);
 }
 
-static const ub32 plt_entry[] = {
+static constexpr ub32 plt_entry[] = {
   // Get the address of this PLT entry
   0x7c08'02a6, // mflr    r0
   0x429f'0005, // bcl     20, 31, 4
@@ -120,14 +122,14 @@ void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
   memcpy(buf, plt_entry, sizeof(plt_entry));
 
   ub32 *loc = (ub32 *)buf;
-  i64 offset = sym.get_got_addr(ctx) - sym.get_plt_addr(ctx) - 8;
+  i64 offset = sym.get_got_pltgot_addr(ctx) - sym.get_plt_addr(ctx) - 8;
   loc[4] |= higha(offset);
   loc[5] |= lo(offset);
 }
 
 template <>
-void EhFrameSection<E>::apply_reloc(Context<E> &ctx, const ElfRel<E> &rel,
-                                    u64 offset, u64 val) {
+void EhFrameSection<E>::apply_eh_reloc(Context<E> &ctx, const ElfRel<E> &rel,
+                                       u64 offset, u64 val) {
   u8 *loc = ctx.buf + this->shdr.sh_offset + offset;
 
   switch (rel.r_type) {
@@ -148,12 +150,7 @@ template <>
 void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
   std::span<const ElfRel<E>> rels = get_rels(ctx);
 
-  ElfRel<E> *dynrel = nullptr;
-  if (ctx.reldyn)
-    dynrel = (ElfRel<E> *)(ctx.buf + ctx.reldyn->shdr.sh_offset +
-                           file.reldyn_offset + this->reldyn_offset);
-
-  u64 GOT2 = file.ppc32_got2 ? file.ppc32_got2->get_addr() : 0;
+  u64 GOT2 = file.extra.got2 ? file.extra.got2->get_addr() : 0;
 
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
@@ -170,10 +167,6 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
     u64 GOT = ctx.got->shdr.sh_addr;
 
     switch (rel.r_type) {
-    case R_PPC_ADDR32:
-    case R_PPC_UADDR32:
-      apply_dyn_absrel(ctx, sym, rel, loc, S, A, P, dynrel);
-      break;
     case R_PPC_ADDR14:
       *(ub32 *)loc |= bits(S + A, 15, 2) << 2;
       break;
@@ -222,15 +215,15 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
     case R_PPC_REL24:
     case R_PPC_LOCAL24PC: {
       i64 val = S + A - P;
-      if (sign_extend(val, 25) != val)
-        val = get_thunk_addr(i) - P;
+      if (!is_int(val, 26))
+        val = sym.get_thunk_addr(ctx, P) - P;
       *(ub32 *)loc |= bits(val, 25, 2) << 2;
       break;
     }
     case R_PPC_PLTREL24: {
       i64 val = S - P;
-      if (sym.has_plt(ctx) || sign_extend(val, 25) != val)
-        val = get_thunk_addr(i) - P;
+      if (sym.has_plt(ctx) || !is_int(val, 26))
+        val = sym.get_thunk_addr(ctx, P) - P;
       *(ub32 *)loc |= bits(val, 25, 2) << 2;
       break;
     }
@@ -275,6 +268,8 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
     case R_PPC_GOT_TPREL16:
       *(ub16 *)loc = sym.get_gottp_addr(ctx) - GOT;
       break;
+    case R_PPC_ADDR32:
+    case R_PPC_UADDR32:
     case R_PPC_TLS:
     case R_PPC_TLSGD:
     case R_PPC_TLSLD:
@@ -293,18 +288,12 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
     u8 *loc = base + rel.r_offset;
 
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
     SectionFragment<E> *frag;
     i64 frag_addend;
     std::tie(frag, frag_addend) = get_fragment(ctx, rel);
@@ -319,6 +308,12 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
       else
         *(ub32 *)loc = S + A;
       break;
+    case R_PPC_DTPREL32:
+      if (std::optional<u64> val = get_tombstone(sym, frag))
+        *(ub32 *)loc = *val;
+      else
+        *(ub32 *)loc = S + A - ctx.dtp_addr;
+      break;
     default:
       Fatal(ctx) << *this << ": invalid relocation for non-allocated sections: "
                  << rel;
@@ -329,32 +324,20 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 template <>
 void InputSection<E>::scan_relocations(Context<E> &ctx) {
   assert(shdr().sh_flags & SHF_ALLOC);
-
-  this->reldyn_offset = file.num_dynrel * sizeof(ElfRel<E>);
   std::span<const ElfRel<E>> rels = get_rels(ctx);
 
   // Scan relocations
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
 
     if (sym.is_ifunc())
       sym.flags |= NEEDS_GOT | NEEDS_PLT;
 
     switch (rel.r_type) {
-    case R_PPC_ADDR32:
-    case R_PPC_UADDR32:
-      scan_dyn_absrel(ctx, sym, rel);
-      break;
     case R_PPC_ADDR14:
     case R_PPC_ADDR16:
     case R_PPC_UADDR16:
@@ -403,6 +386,8 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
     case R_PPC_TPREL16_HA:
       check_tlsle(ctx, sym, rel);
       break;
+    case R_PPC_ADDR32:
+    case R_PPC_UADDR32:
     case R_PPC_LOCAL24PC:
     case R_PPC_TLS:
     case R_PPC_TLSGD:
@@ -420,10 +405,8 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
 }
 
 template <>
-void RangeExtensionThunk<E>::copy_buf(Context<E> &ctx) {
-  u8 *buf = ctx.buf + output_section.shdr.sh_offset + offset;
-
-  static const ub32 local_thunk[] = {
+void Thunk<E>::copy_buf(Context<E> &ctx) {
+  constexpr ub32 local_thunk[] = {
     // Get this thunk's address
     0x7c08'02a6, // mflr    r0
     0x429f'0005, // bcl     20, 31, 4
@@ -441,23 +424,28 @@ void RangeExtensionThunk<E>::copy_buf(Context<E> &ctx) {
   static_assert(E::thunk_size == sizeof(plt_entry));
   static_assert(E::thunk_size == sizeof(local_thunk));
 
+  u8 *base = ctx.buf + output_section.shdr.sh_offset + offset;
+
   for (i64 i = 0; i < symbols.size(); i++) {
-    ub32 *loc = (ub32 *)(buf + i * E::thunk_size);
     Symbol<E> &sym = *symbols[i];
+    u64 P = get_addr() + offsets[i];
+    u8 *buf = base + offsets[i];
 
     if (sym.has_plt(ctx)) {
-      memcpy(loc, plt_entry, sizeof(plt_entry));
       u64 got = sym.has_got(ctx) ? sym.get_got_addr(ctx) : sym.get_gotplt_addr(ctx);
-      i64 val = got - get_addr(i) - 8;
-      loc[4] |= higha(val);
-      loc[5] |= lo(val);
+      i64 val = got - P - 8;
+      memcpy(buf, plt_entry, sizeof(plt_entry));
+      *(ub32 *)(buf + 16) |= higha(val);
+      *(ub32 *)(buf + 20) |= lo(val);
     } else {
-      memcpy(loc, local_thunk, sizeof(local_thunk));
-      i64 val = sym.get_addr(ctx) - get_addr(i) - 8;
-      loc[4] |= higha(val);
-      loc[5] |= lo(val);
+      i64 val = sym.get_addr(ctx) - P - 8;
+      memcpy(buf, local_thunk, sizeof(local_thunk));
+      *(ub32 *)(buf + 16) |= higha(val);
+      *(ub32 *)(buf + 20) |= lo(val);
     }
   }
 }
 
-} // namespace mold::elf
+} // namespace mold
+
+#endif

src/arch-ppc64v1.cc

@@ -5,8 +5,8 @@
 //
 // Even though they are similiar, ELFv1 isn't only different from ELFv2 in
 // endianness. The most notable difference is, in ELFv1, a function
-// pointer doesn't directly refer the entry point of a function but
-// instead refers a data structure so-called "function descriptor".
+// pointer doesn't directly refer to the entry point of a function but
+// instead refers to a data structure so-called "function descriptor".
 //
 // The function descriptor is essentially a pair of a function entry point
 // address and a value that should be set to %r2 before calling that
@@ -26,8 +26,8 @@
 //
 // In this way, you can't call a function just by knowing the function's
 // entry point address. You also need to know a proper %r2 value for the
-// function. This is why a function pointer refers a tuple of an address
-// and a %r2 value.
+// function. This is why a function pointer refers to a tuple of an
+// address and a %r2 value.
 //
 // If a function call is made through PLT, PLT takes care of restoring %r2.
 // Therefore, the caller has to restore %r2 only for function calls
@@ -40,17 +40,19 @@
 // few different addresses for different purposes. It may not only have an
 // entry point address but may also have PLT and/or GOT addresses.
 // In PPCV1, it may have an OPD address in addition to these. OPD address
-// is used for relocations that refers the address of a function as a
+// is used for relocations that refers to the address of a function as a
 // function pointer.
 //
 // https://github.com/rui314/psabi/blob/main/ppc64v1.pdf
 
+#if MOLD_PPC64V1
+
 #include "mold.h"
 
 #include <algorithm>
 #include <tbb/parallel_for_each.h>
 
-namespace mold::elf {
+namespace mold {
 
 using E = PPC64V1;
 
@@ -68,26 +70,26 @@ static u64 higha(u64 x) { return ((x + 0x8000) >> 16) & 0xffff; }
 // resolved addresses.
 template <>
 void write_plt_header(Context<E> &ctx, u8 *buf) {
-  static const ub32 insn[] = {
+  constexpr ub32 insn[] = {
     0x7d88'02a6, // mflr    r12
     0x429f'0005, // bcl     20, 31, 4 // obtain PC
     0x7d68'02a6, // mflr    r11
-    0xe84b'0024, // ld      r2,36(r11)
     0x7d88'03a6, // mtlr    r12
-    0x7d62'5a14, // add     r11,r2,r11
+    0x3d6b'0000, // addis   r11, r11, GOTPLT_OFFSET@ha
+    0x396b'0000, // addi    r11, r11, GOTPLT_OFFSET@lo
     0xe98b'0000, // ld      r12,0(r11)
     0xe84b'0008, // ld      r2,8(r11)
     0x7d89'03a6, // mtctr   r12
     0xe96b'0010, // ld      r11,16(r11)
     0x4e80'0420, // bctr
-    // .quad .got.plt - .plt - 8
-    0x0000'0000,
-    0x0000'0000,
   };
 
   static_assert(sizeof(insn) == E::plt_hdr_size);
   memcpy(buf, insn, sizeof(insn));
-  *(ub64 *)(buf + 44) = ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 8;
+
+  i64 val = ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 8;
+  *(ub32 *)(buf + 16) |= higha(val);
+  *(ub32 *)(buf + 20) |= lo(val);
 }
 
 template <>
@@ -101,7 +103,7 @@ void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
   // call to the PLT entry jumps to. So we need to strictly follow the PLT
   // section layout as the loader expect it to be.
   if (idx < 0x8000) {
-    static const ub32 insn[] = {
+    constexpr ub32 insn[] = {
       0x3800'0000, // li      r0, PLT_INDEX
       0x4b00'0000, // b       plt0
     };
@@ -110,7 +112,7 @@ void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
     loc[0] |= idx;
     loc[1] |= (ctx.plt->shdr.sh_addr - sym.get_plt_addr(ctx) - 4) & 0x00ff'ffff;
   } else {
-    static const ub32 insn[] = {
+    constexpr ub32 insn[] = {
       0x3c00'0000, // lis     r0, PLT_INDEX@high
       0x6000'0000, // ori     r0, r0, PLT_INDEX@lo
       0x4b00'0000, // b       plt0
@@ -129,8 +131,8 @@ template <>
 void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {}
 
 template <>
-void EhFrameSection<E>::apply_reloc(Context<E> &ctx, const ElfRel<E> &rel,
-                                    u64 offset, u64 val) {
+void EhFrameSection<E>::apply_eh_reloc(Context<E> &ctx, const ElfRel<E> &rel,
+                                       u64 offset, u64 val) {
   u8 *loc = ctx.buf + this->shdr.sh_offset + offset;
 
   switch (rel.r_type) {
@@ -154,11 +156,6 @@ template <>
 void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
   std::span<const ElfRel<E>> rels = get_rels(ctx);
 
-  ElfRel<E> *dynrel = nullptr;
-  if (ctx.reldyn)
-    dynrel = (ElfRel<E> *)(ctx.buf + ctx.reldyn->shdr.sh_offset +
-                           file.reldyn_offset + this->reldyn_offset);
-
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
     if (rel.r_type == R_NONE)
@@ -167,13 +164,6 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
     Symbol<E> &sym = *file.symbols[rel.r_sym];
     u8 *loc = base + rel.r_offset;
 
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
     u64 S = sym.get_addr(ctx);
     u64 A = rel.r_addend;
     u64 P = get_addr() + rel.r_offset;
@@ -181,12 +171,12 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
     u64 GOT = ctx.got->shdr.sh_addr;
     u64 TOC = ctx.extra.TOC->value;
 
+    auto check = [&](i64 val, i64 lo, i64 hi) {
+      check_range(ctx, i, val, lo, hi);
+    };
+
     switch (rel.r_type) {
-    case R_PPC64_ADDR64:
-      apply_toc_rel(ctx, sym, rel, loc, S, A, P, dynrel);
-      break;
     case R_PPC64_TOC:
-      apply_toc_rel(ctx, *ctx.extra.TOC, rel, loc, TOC, A, P, dynrel);
       break;
     case R_PPC64_TOC16_HA:
       *(ub16 *)loc = ha(S + A - TOC);
@@ -203,8 +193,8 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
       break;
     case R_PPC64_REL24: {
       i64 val = sym.get_addr(ctx, NO_OPD) + A - P;
-      if (sym.has_plt(ctx) || sign_extend(val, 25) != val)
-        val = get_thunk_addr(i) + A - P;
+      if (sym.has_plt(ctx) || !is_int(val, 26))
+        val = sym.get_thunk_addr(ctx, P) + A - P;
 
       check(val, -(1 << 25), 1 << 25);
       *(ub32 *)loc |= bits(val, 25, 2) << 2;
@@ -217,6 +207,9 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
         *(ub32 *)(loc + 4) = 0xe841'0028; // ld r2, 40(r1)
       break;
     }
+    case R_PPC64_REL32:
+      *(ub32 *)loc = S + A - P;
+      break;
     case R_PPC64_REL64:
       *(ub64 *)loc = S + A - P;
       break;
@@ -226,6 +219,9 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
     case R_PPC64_REL16_LO:
       *(ub16 *)loc = lo(S + A - P);
       break;
+    case R_PPC64_GOT16:
+      *(ub16 *)loc = G - TOC;
+      break;
     case R_PPC64_PLT16_HA:
       *(ub16 *)loc = ha(G + GOT - TOC);
       break;
@@ -256,18 +252,25 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
     case R_PPC64_DTPREL16_HA:
       *(ub16 *)loc = ha(S + A - ctx.dtp_addr);
       break;
-    case R_PPC64_TPREL16_HA:
-      *(ub16 *)loc = ha(S + A - ctx.tp_addr);
-      break;
     case R_PPC64_DTPREL16_LO:
       *(ub16 *)loc = lo(S + A - ctx.dtp_addr);
       break;
+    case R_PPC64_DTPREL16_LO_DS:
+      *(ub16 *)loc |= (S + A - ctx.dtp_addr) & 0xfffc;
+      break;
+    case R_PPC64_TPREL16_HA:
+      *(ub16 *)loc = ha(S + A - ctx.tp_addr);
+      break;
     case R_PPC64_TPREL16_LO:
       *(ub16 *)loc = lo(S + A - ctx.tp_addr);
       break;
+    case R_PPC64_TPREL16_LO_DS:
+      *(ub16 *)loc |= (S + A - ctx.tp_addr) & 0xfffc;
+      break;
     case R_PPC64_GOT_TPREL16_LO_DS:
       *(ub16 *)loc |= (sym.get_gottp_addr(ctx) - TOC) & 0xfffc;
       break;
+    case R_PPC64_ADDR64:
     case R_PPC64_PLTSEQ:
     case R_PPC64_PLTCALL:
     case R_PPC64_TLS:
@@ -286,25 +289,12 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
     u8 *loc = base + rel.r_offset;
 
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
     SectionFragment<E> *frag;
     i64 frag_addend;
     std::tie(frag, frag_addend) = get_fragment(ctx, rel);
@@ -312,6 +302,10 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
     u64 S = frag ? frag->get_addr(ctx) : sym.get_addr(ctx);
     u64 A = frag ? frag_addend : (i64)rel.r_addend;
 
+    auto check = [&](i64 val, i64 lo, i64 hi) {
+      check_range(ctx, val, i, lo, hi);
+    };
+
     switch (rel.r_type) {
     case R_PPC64_ADDR64:
       if (std::optional<u64> val = get_tombstone(sym, frag))
@@ -319,12 +313,10 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
       else
         *(ub64 *)loc = S + A;
       break;
-    case R_PPC64_ADDR32: {
-      i64 val = S + A;
-      check(val, 0, 1LL << 32);
-      *(ub32 *)loc = val;
+    case R_PPC64_ADDR32:
+      check(S + A, 0, 1LL << 32);
+      *(ub32 *)loc = S + A;
       break;
-    }
     case R_PPC64_DTPREL64:
       *(ub64 *)loc = S + A - ctx.dtp_addr;
       break;
@@ -338,23 +330,15 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 template <>
 void InputSection<E>::scan_relocations(Context<E> &ctx) {
   assert(shdr().sh_flags & SHF_ALLOC);
-
-  this->reldyn_offset = file.num_dynrel * sizeof(ElfRel<E>);
   std::span<const ElfRel<E>> rels = get_rels(ctx);
 
   // Scan relocations
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
 
     if (sym.is_ifunc())
       sym.flags |= NEEDS_GOT | NEEDS_PLT | NEEDS_PPC_OPD;
@@ -365,12 +349,6 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
       sym.flags |= NEEDS_PPC_OPD;
 
     switch (rel.r_type) {
-    case R_PPC64_ADDR64:
-      scan_toc_rel(ctx, sym, rel);
-      break;
-    case R_PPC64_TOC:
-      scan_toc_rel(ctx, sym, rel);
-      break;
     case R_PPC64_GOT_TPREL16_HA:
       sym.flags |= NEEDS_GOTTP;
       break;
@@ -378,6 +356,7 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
       if (sym.is_imported)
         sym.flags |= NEEDS_PLT;
       break;
+    case R_PPC64_GOT16:
     case R_PPC64_PLT16_HA:
       sym.flags |= NEEDS_GOT;
       break;
@@ -389,8 +368,12 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
       break;
     case R_PPC64_TPREL16_HA:
     case R_PPC64_TPREL16_LO:
+    case R_PPC64_TPREL16_LO_DS:
       check_tlsle(ctx, sym, rel);
       break;
+    case R_PPC64_ADDR64:
+    case R_PPC64_TOC:
+    case R_PPC64_REL32:
     case R_PPC64_REL64:
     case R_PPC64_TOC16_HA:
     case R_PPC64_TOC16_LO:
@@ -411,6 +394,7 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
     case R_PPC64_TLSLD:
     case R_PPC64_DTPREL16_HA:
     case R_PPC64_DTPREL16_LO:
+    case R_PPC64_DTPREL16_LO_DS:
       break;
     default:
       Error(ctx) << *this << ": unknown relocation: " << rel;
@@ -419,13 +403,11 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
 }
 
 template <>
-void RangeExtensionThunk<E>::copy_buf(Context<E> &ctx) {
-  u8 *buf = ctx.buf + output_section.shdr.sh_offset + offset;
-
+void Thunk<E>::copy_buf(Context<E> &ctx) {
   // If the destination is .plt.got, we save the current r2, read an
   // address of a function descriptor from .got, restore %r2 and jump
   // to the function.
-  static const ub32 pltgot_thunk[] = {
+  constexpr ub32 pltgot_thunk[] = {
     // Store the caller's %r2
     0xf841'0028, // std   %r2, 40(%r1)
 
@@ -443,7 +425,7 @@ void RangeExtensionThunk<E>::copy_buf(Context<E> &ctx) {
   };
 
   // If the destination is .plt, read a function descriptor from .got.plt.
-  static const ub32 plt_thunk[] = {
+  constexpr ub32 plt_thunk[] = {
     // Store the caller's %r2
     0xf841'0028, // std   %r2, 40(%r1)
 
@@ -462,7 +444,7 @@ void RangeExtensionThunk<E>::copy_buf(Context<E> &ctx) {
 
   // If the destination is a non-imported function, we directly jump
   // to the function entry address.
-  static const ub32 local_thunk[] = {
+  constexpr ub32 local_thunk[] = {
     0x3d82'0000, // addis r12, r2,  foo@toc@ha
     0x398c'0000, // addi  r12, r12, foo@toc@lo
     0x7d89'03a6, // mtctr r12
@@ -476,65 +458,61 @@ void RangeExtensionThunk<E>::copy_buf(Context<E> &ctx) {
   static_assert(E::thunk_size == sizeof(plt_thunk));
   static_assert(E::thunk_size == sizeof(local_thunk));
 
+  u8 *base = ctx.buf + output_section.shdr.sh_offset + offset;
+  u64 TOC = ctx.extra.TOC->value;
+
   for (i64 i = 0; i < symbols.size(); i++) {
     Symbol<E> &sym = *symbols[i];
-    ub32 *loc = (ub32 *)(buf + i * E::thunk_size);
+    u8 *buf = base + offsets[i];
 
     if (sym.has_got(ctx)) {
-      memcpy(loc, pltgot_thunk, sizeof(pltgot_thunk));
-      i64 val = sym.get_got_addr(ctx) - ctx.extra.TOC->value;
-      loc[1] |= higha(val);
-      loc[2] |= lo(val);
+      memcpy(buf, pltgot_thunk, sizeof(pltgot_thunk));
+      i64 val = sym.get_got_addr(ctx) - TOC;
+      *(ub32 *)(buf + 4) |= higha(val);
+      *(ub32 *)(buf + 8) |= lo(val);
     } else if(sym.has_plt(ctx)) {
-      memcpy(loc, plt_thunk, sizeof(plt_thunk));
-      i64 val = sym.get_gotplt_addr(ctx) - ctx.extra.TOC->value;
-      loc[1] |= higha(val);
-      loc[2] |= lo(val);
+      memcpy(buf, plt_thunk, sizeof(plt_thunk));
+      i64 val = sym.get_gotplt_addr(ctx) - TOC;
+      *(ub32 *)(buf + 4) |= higha(val);
+      *(ub32 *)(buf + 8) |= lo(val);
     } else {
-      memcpy(loc, local_thunk, sizeof(local_thunk));
-      i64 val = sym.get_addr(ctx, NO_OPD) - ctx.extra.TOC->value;
-      loc[0] |= higha(val);
-      loc[1] |= lo(val);
+      memcpy(buf, local_thunk, sizeof(local_thunk));
+      i64 val = sym.get_addr(ctx, NO_OPD) - TOC;
+      *(ub32 *)buf |= higha(val);
+      *(ub32 *)(buf + 4) |= lo(val);
     }
   }
 }
 
 static InputSection<E> *get_opd_section(ObjectFile<E> &file) {
   for (std::unique_ptr<InputSection<E>> &isec : file.sections)
-    if (isec && isec->name() == ".opd")
+    if (isec && isec->name == ".opd")
       return isec.get();
   return nullptr;
 }
 
 static ElfRel<E> *
-get_relocation_at(Context<E> &ctx, InputSection<E> &isec, i64 offset) {
+get_relocation_at(Context<E> &ctx, InputSection<E> &isec, u64 offset) {
   std::span<ElfRel<E>> rels = isec.get_rels(ctx);
-
-  auto it = std::lower_bound(rels.begin(), rels.end(), offset,
-                             [](const ElfRel<E> &r, i64 offset) {
-    return r.r_offset < offset;
+  auto it = ranges::lower_bound(rels, offset, {}, [](const ElfRel<E> &r) {
+    return (u64)r.r_offset;
   });
-
-  if (it == rels.end())
-    return nullptr;
-  if (it->r_offset != offset)
+  if (it == rels.end() || it->r_offset != offset)
     return nullptr;
   return &*it;
 }
 
+namespace {
 struct OpdSymbol {
-  bool operator<(const OpdSymbol &x) const { return r_offset < x.r_offset; }
-
   u64 r_offset = 0;
   Symbol<E> *sym = nullptr;
 };
+}
 
 static Symbol<E> *
-get_opd_sym_at(Context<E> &ctx, std::span<OpdSymbol> syms, u64 offset) {
-  auto it = std::lower_bound(syms.begin(), syms.end(), OpdSymbol{offset});
-  if (it == syms.end())
-    return nullptr;
-  if (it->r_offset != offset)
+get_opd_sym_at(std::span<OpdSymbol> syms, u64 offset) {
+  auto it = ranges::lower_bound(syms, offset, {}, &OpdSymbol::r_offset);
+  if (it == syms.end() || it->r_offset != offset)
     return nullptr;
   return it->sym;
 }
@@ -547,10 +525,10 @@ get_opd_sym_at(Context<E> &ctx, std::span<OpdSymbol> syms, u64 offset) {
 // However, in reality, .opd isn't a normal input section. It needs many
 // special treatments as follows:
 //
-// 1. A function symbol refers not a .text but an .opd. Its address works
-//    fine for address-taking relocations such as R_PPC64_ADDR64. However,
-//    R_PPC64_REL24 (which is used for branch instruction) needs a
-//    function's real address instead of the function's .opd address.
+// 1. A function symbol refers to not a .text but an .opd. Its address
+//    works fine for address-taking relocations such as R_PPC64_ADDR64.
+//    However, R_PPC64_REL24 (which is used for branch instruction) needs
+//    a function's real address instead of the function's .opd address.
 //    We need to read .opd contents to find out a function entry point
 //    address to apply R_PPC64_REL24.
 //
@@ -558,9 +536,9 @@ get_opd_sym_at(Context<E> &ctx, std::span<OpdSymbol> syms, u64 offset) {
 //    are taken. Just copying input .opd sections to an output would
 //    produces lots of dead .opd entries.
 //
-// 3. In this design, all function symbols refer an .opd section, and that
-//    doesn't work well with graph traversal optimizations such as garbage
-//    collection or identical comdat folding. For example, garbage
+// 3. In this design, all function symbols refer to an .opd section, and
+//    that doesn't work well with graph traversal optimizations such as
+//    garbage collection or identical comdat folding. For example, garbage
 //    collector would mark an .opd alive which in turn mark all functions
 //    thatare referenced by .opd as alive, effectively keeping all
 //    functions as alive.
@@ -573,9 +551,9 @@ get_opd_sym_at(Context<E> &ctx, std::span<OpdSymbol> syms, u64 offset) {
 //
 // So, in this function, we undo what the compiler did to .opd. We remove
 // function symbols from .opd and reattach them to their function entry
-// points. We also rewrite relocations that directly refer an input .opd
-// section so that they refer function symbols instead. We then mark input
-// .opd sections as dead.
+// points. We also rewrite relocations that directly refer to an input
+// .opd  section so that they refer to function symbols instead. We then
+// mark input .opd sections as dead.
 //
 // After this function, we mark symbols with the NEEDS_PPC_OPD flag if the
 // symbol needs an .opd entry. We then create an output .opd just like we
@@ -604,7 +582,7 @@ void ppc64v1_rewrite_opd(Context<E> &ctx) {
 
       Symbol<E> *sym2 = file->symbols[rel->r_sym];
       if (sym2->get_type() != STT_SECTION)
-        Fatal(ctx) << *file << ": bad relocation in .opd referring " << *sym2;
+        Fatal(ctx) << *file << ": bad relocation in .opd referring to " << *sym2;
 
       opd_syms.push_back({sym->value, sym});
 
@@ -613,7 +591,7 @@ void ppc64v1_rewrite_opd(Context<E> &ctx) {
     }
 
     // Sort symbols so that get_opd_sym_at() can do binary search.
-    sort(opd_syms);
+    ranges::stable_sort(opd_syms, {}, &OpdSymbol::r_offset);
 
     // Rewrite relocations so that they directly refer to .opd.
     for (std::unique_ptr<InputSection<E>> &isec : file->sections) {
@@ -625,7 +603,7 @@ void ppc64v1_rewrite_opd(Context<E> &ctx) {
         if (sym.get_input_section() != opd)
           continue;
 
-        Symbol<E> *real_sym = get_opd_sym_at(ctx, opd_syms, r.r_addend);
+        Symbol<E> *real_sym = get_opd_sym_at(opd_syms, r.r_addend);
         if (!real_sym)
           Fatal(ctx) << *isec << ": cannot find a symbol in .opd for " << r
                      << " at offset 0x" << std::hex << (u64)r.r_addend;
@@ -638,8 +616,8 @@ void ppc64v1_rewrite_opd(Context<E> &ctx) {
 }
 
 // When a function is exported, the dynamic symbol for the function should
-// refers the function's .opd entry. This function marks such symbols with
-// NEEDS_PPC_OPD.
+// refers to the function's .opd entry. This function marks such symbols
+// with NEEDS_PPC_OPD.
 void ppc64v1_scan_symbols(Context<E> &ctx) {
   tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
     for (Symbol<E> *sym : file->symbols)
@@ -649,15 +627,14 @@ void ppc64v1_scan_symbols(Context<E> &ctx) {
   });
 
   // Functions referenced by the ELF header also have to have .opd entries.
-  auto mark = [&](std::string_view name) {
-    if (!name.empty())
-      if (Symbol<E> &sym = *get_symbol(ctx, name); !sym.is_imported)
-        sym.flags |= NEEDS_PPC_OPD;
-  };
+  if (!ctx.arg.entry->is_imported)
+    ctx.arg.entry->flags |= NEEDS_PPC_OPD;
 
-  mark(ctx.arg.entry);
-  mark(ctx.arg.init);
-  mark(ctx.arg.fini);
+  if (!ctx.arg.init->is_imported)
+    ctx.arg.init->flags |= NEEDS_PPC_OPD;
+
+  if (!ctx.arg.fini->is_imported)
+    ctx.arg.fini->flags |= NEEDS_PPC_OPD;
 }
 
 void PPC64OpdSection::add_symbol(Context<E> &ctx, Symbol<E> *sym) {
@@ -666,31 +643,31 @@ void PPC64OpdSection::add_symbol(Context<E> &ctx, Symbol<E> *sym) {
   this->shdr.sh_size += ENTRY_SIZE;
 }
 
-i64 PPC64OpdSection::get_reldyn_size(Context<E> &ctx) const {
-  if (ctx.arg.pic)
-    return symbols.size() * 2;
-  return 0;
+std::vector<ElfRel<E>> PPC64OpdSection::collect_dynrels(Context<E> &ctx) const {
+  if (!ctx.arg.pic)
+    return {};
+
+  std::vector<ElfRel<E>> rels;
+
+  for (Symbol<E> *sym : symbols) {
+    u64 loc = sym->get_opd_addr(ctx);
+    rels.emplace_back(loc, E::R_RELATIVE, 0, sym->get_addr(ctx, NO_PLT | NO_OPD));
+    rels.emplace_back(loc + 8, E::R_RELATIVE, 0, ctx.extra.TOC->value);
+  }
+  return rels;
 }
 
 void PPC64OpdSection::copy_buf(Context<E> &ctx) {
   ub64 *buf = (ub64 *)(ctx.buf + this->shdr.sh_offset);
 
-  ElfRel<E> *rel = nullptr;
-  if (ctx.arg.pic)
-    rel = (ElfRel<E> *)(ctx.buf + ctx.reldyn->shdr.sh_offset + reldyn_offset);
-
   for (Symbol<E> *sym : symbols) {
     u64 addr = sym->get_addr(ctx, NO_PLT | NO_OPD);
     *buf++ = addr;
     *buf++ = ctx.extra.TOC->value;
     *buf++ = 0;
-
-    if (ctx.arg.pic) {
-      u64 loc = sym->get_opd_addr(ctx);
-      *rel++ = ElfRel<E>(loc, E::R_RELATIVE, 0, addr);
-      *rel++ = ElfRel<E>(loc + 8, E::R_RELATIVE, 0, ctx.extra.TOC->value);
-    }
   }
 }
 
-} // namespace mold::elf
+} // namespace mold
+
+#endif

src/arch-ppc64v2.cc

@@ -0,0 +1,682 @@
+// This file implements the PowerPC ELFv2 ABI which was standardized in
+// 2014. Modern little-endian PowerPC systems are based on this ABI.
+// The ABI is often referred to as "ppc64le". This shouldn't be confused
+// with "ppc64" which refers to the original, big-endian PowerPC systems.
+//
+// PPC64 is a bit tricky to support because PC-relative load/store
+// instructions hadn't been available until Power10 which debuted in 2021.
+// Prior to Power10, it wasn't trivial for position-independent code (PIC)
+// to load a value from, for example, .got, as we can't do that with [PC +
+// the offset to the .got entry].
+//
+// In the following, I'll explain how PIC is supported on pre-Power10
+// systems first and then explain what has changed with Power10.
+//
+//
+// Position-independent code on Power9 or earlier:
+//
+// We can get the program counter on older PPC64 systems with the
+// following four instructions
+//
+//   mflr  r1  // save the current link register to r1
+//   bl    .+4 // branch to the next instruction as if it were a function
+//   mflr  r0  // copy the return address to r0
+//   mtlr  r1  // restore the original link register value
+//
+// , but it's too expensive to do if we do this for each load/store.
+//
+// As a workaround, most functions are compiled in such a way that r2 is
+// assumed to always contain the address of .got + 0x8000. With this, we
+// can for example load the first entry of .got with a single instruction
+// `lw r0, -0x8000(r2)`. r2 is called the TOC pointer.
+//
+// There's only one .got for each ELF module. Therefore, if a callee is in
+// the same ELF module, r2 doesn't have to be recomputed. Most function
+// calls are usually within the same ELF module, so this mechanism is
+// efficient.
+//
+// A function compiled for pre-Power10 usually has two entry points,
+// global and local. The global entry point usually 8 bytes precedes
+// the local entry point. In between is the following instructions:
+//
+//   addis r2, r12, .TOC.@ha
+//   addi  r2, r2,  .TOC.@lo + 4;
+//
+// The global entry point assumes that the address of itself is in r12,
+// and it computes its own TOC pointer from r12. It's easy to do so for
+// the callee because the offset between its .got + 0x8000 and the
+// function is known at link-time. The above code sequence then falls
+// through to the local entry point that assumes r2 is .got + 0x8000.
+//
+// So, if a callee's TOC pointer is different from the current one
+// (e.g. calling a function in another .so), we first load the callee's
+// address to r12 (e.g. from .got.plt with a r2-relative load) and branch
+// to that address. Then the callee computes its own TOC pointer using
+// r12.
+//
+//
+// Position-independent code on Power10:
+//
+// Power10 added 8-bytes-long instructions to the ISA. Some of them are
+// PC-relative load/store instructions that take 34 bits offsets.
+// Functions compiled with `-mcpu=power10` use these instructions for PIC.
+// r2 does not have a special meaning in such fucntions.
+//
+// When a fucntion compiled for Power10 calls a function that uses the TOC
+// pointer, we need to compute a correct value for TOC and set it to r2
+// before transferring the control to the callee. Thunks are responsible
+// for doing it.
+//
+// `_NOTOC` relocations such as `R_PPC64_REL24_NOTOC` indicate that the
+// callee does not use TOC (i.e. compiled with `-mcpu=power10`). If a
+// function using TOC is referenced via a `_NOTOC` relocation, that call
+// is made through a range extension thunk.
+//
+//
+// Note on section names: the PPC64 psABI uses a weird naming convention
+// which calls .got.plt .plt. We ignored that part because it's just
+// confusing. Since the runtime only cares about segments, we should be
+// able to name sections whatever we want.
+//
+// https://github.com/rui314/psabi/blob/main/ppc64v2.pdf
+
+#if MOLD_PPC64V2
+
+#include "mold.h"
+
+namespace mold {
+
+using E = PPC64V2;
+
+static u64 lo(u64 x)    { return x & 0xffff; }
+static u64 hi(u64 x)    { return x >> 16; }
+static u64 ha(u64 x)    { return (x + 0x8000) >> 16; }
+static u64 high(u64 x)  { return (x >> 16) & 0xffff; }
+static u64 higha(u64 x) { return ((x + 0x8000) >> 16) & 0xffff; }
+
+static void write34(u8 *loc, u64 x) {
+  ul32 *buf = (ul32 *)loc;
+  buf[0] = (buf[0] & 0xfffc'0000) | bits(x, 33, 16);
+  buf[1] = (buf[1] & 0xffff'0000) | bits(x, 15, 0);
+}
+
+// .plt is used only for lazy symbol resolution on PPC64. All PLT
+// calls are made via range extension thunks even if they are within
+// reach. Thunks read addresses from .got.plt and jump there.
+// Therefore, once PLT symbols are resolved and final addresses are
+// written to .got.plt, thunks just skip .plt and directly jump to the
+// resolved addresses.
+template <>
+void write_plt_header(Context<E> &ctx, u8 *buf) {
+  constexpr ul32 insn[] = {
+    // Get PC
+    0x7c08'02a6, // mflr    r0
+    0x429f'0005, // bcl     20, 31, 4 // obtain PC
+    0x7d68'02a6, // mflr    r11
+    0x7c08'03a6, // mtlr    r0
+
+    // Compute the PLT entry index
+    0x398c'ffd4, // addi    r12, r12, -44
+    0x7c0b'6050, // subf    r0, r11, r12
+    0x7800'f082, // rldicl  r0, r0, 62, 2
+
+    // Compute the address of .got.plt
+    0x3d6b'0000, // addis   r11, r11, GOTPLT_OFFSET@ha
+    0x396b'0000, // addi    r11, r11, GOTPLT_OFFSET@lo
+
+    // Load .got.plt[0] and .got.plt[1] and branch to .got.plt[0]
+    0xe98b'0000, // ld      r12, 0(r11)
+    0x7d89'03a6, // mtctr   r12
+    0xe96b'0008, // ld      r11, 8(r11)
+    0x4e80'0420, // bctr
+  };
+
+  memcpy(buf, insn, sizeof(insn));
+
+  i64 val = ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 8;
+  *(ul32 *)(buf + 28) |= higha(val);
+  *(ul32 *)(buf + 32) |= lo(val);
+}
+
+template <>
+void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
+  // When the control is transferred to a PLT entry, the PLT entry's
+  // address is already set to %r12 by the caller.
+  i64 offset = ctx.plt->shdr.sh_addr - sym.get_plt_addr(ctx);
+  *(ul32 *)buf = 0x4b00'0000 | (offset & 0x00ff'ffff);        // b plt0
+}
+
+// .plt.got is not necessary on PPC64 because range extension thunks
+// directly read GOT entries and jump there.
+template <>
+void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {}
+
+template <>
+void EhFrameSection<E>::apply_eh_reloc(Context<E> &ctx, const ElfRel<E> &rel,
+                                       u64 offset, u64 val) {
+  u8 *loc = ctx.buf + this->shdr.sh_offset + offset;
+
+  switch (rel.r_type) {
+  case R_NONE:
+    break;
+  case R_PPC64_ADDR64:
+    *(ul64 *)loc = val;
+    break;
+  case R_PPC64_REL32:
+    *(ul32 *)loc = val - this->shdr.sh_addr - offset;
+    break;
+  case R_PPC64_REL64:
+    *(ul64 *)loc = val - this->shdr.sh_addr - offset;
+    break;
+  default:
+    Fatal(ctx) << "unsupported relocation in .eh_frame: " << rel;
+  }
+}
+
+static u64 get_local_entry_offset(Context<E> &ctx, Symbol<E> &sym) {
+  i64 val = sym.esym().ppc64_local_entry;
+  assert(val <= 7);
+  if (val == 7)
+    Fatal(ctx) << sym << ": local entry offset 7 is reserved";
+
+  if (val == 0 || val == 1)
+    return 0;
+  return 1 << val;
+}
+
+template <>
+void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
+  std::span<const ElfRel<E>> rels = get_rels(ctx);
+
+  for (i64 i = 0; i < rels.size(); i++) {
+    const ElfRel<E> &rel = rels[i];
+    if (rel.r_type == R_NONE)
+      continue;
+
+    Symbol<E> &sym = *file.symbols[rel.r_sym];
+    u8 *loc = base + rel.r_offset;
+
+    u64 S = sym.get_addr(ctx);
+    u64 A = rel.r_addend;
+    u64 P = get_addr() + rel.r_offset;
+    u64 G = sym.get_got_idx(ctx) * sizeof(Word<E>);
+    u64 GOT = ctx.got->shdr.sh_addr;
+    u64 TOC = ctx.extra.TOC->value;
+
+    auto r2save_thunk_addr = [&] { return sym.get_thunk_addr(ctx, P); };
+    auto no_r2save_thunk_addr = [&] { return sym.get_thunk_addr(ctx, P) + 8; };
+
+    switch (rel.r_type) {
+    case R_PPC64_TOC16_HA:
+      *(ul16 *)loc = ha(S + A - TOC);
+      break;
+    case R_PPC64_TOC16_LO:
+      *(ul16 *)loc = lo(S + A - TOC);
+      break;
+    case R_PPC64_TOC16_DS:
+    case R_PPC64_TOC16_LO_DS:
+      *(ul16 *)loc |= (S + A - TOC) & 0xfffc;
+      break;
+    case R_PPC64_REL24:
+      if (sym.has_plt(ctx) || !sym.esym().ppc64_preserves_r2()) {
+        i64 val = r2save_thunk_addr() + A - P;
+        *(ul32 *)loc |= bits(val, 25, 2) << 2;
+
+        // The thunk saves %r2 to the caller's r2 save slot. We need to
+        // restore it after function return. To do so, there's usually a
+        // NOP as a placeholder after a BL. 0x6000'0000 is a NOP.
+        if (*(ul32 *)(loc + 4) == 0x6000'0000)
+          *(ul32 *)(loc + 4) = 0xe841'0018; // ld r2, 24(r1)
+      } else {
+        i64 val = S + get_local_entry_offset(ctx, sym) + A - P;
+        if (!is_int(val, 26))
+          val = no_r2save_thunk_addr() + A - P;
+        *(ul32 *)loc |= bits(val, 25, 2) << 2;
+      }
+      break;
+    case R_PPC64_REL24_NOTOC:
+      if (sym.has_plt(ctx) || sym.esym().ppc64_uses_toc()) {
+        i64 val = no_r2save_thunk_addr() + A - P;
+        *(ul32 *)loc |= bits(val, 25, 2) << 2;
+      } else {
+        i64 val = S + A - P;
+        if (!is_int(val, 26))
+          val = no_r2save_thunk_addr() + A - P;
+        *(ul32 *)loc |= bits(val, 25, 2) << 2;
+      }
+      break;
+    case R_PPC64_REL14:
+      *(ul32 *)loc |= bits(S + A - P, 15, 2) << 2;
+      break;
+    case R_PPC64_REL32:
+      *(ul32 *)loc = S + A - P;
+      break;
+    case R_PPC64_REL64:
+      *(ul64 *)loc = S + A - P;
+      break;
+    case R_PPC64_REL16_HA:
+      *(ul16 *)loc = ha(S + A - P);
+      break;
+    case R_PPC64_REL16_LO:
+      *(ul16 *)loc = lo(S + A - P);
+      break;
+    case R_PPC64_GOT16:
+      *(ul16 *)loc = G - TOC;
+      break;
+    case R_PPC64_GOT16_LO:
+      *(ul16 *)loc = lo(G - TOC);
+      break;
+    case R_PPC64_GOT16_HI:
+      *(ul16 *)loc = hi(G - TOC);
+      break;
+    case R_PPC64_GOT16_HA:
+      *(ul16 *)loc = ha(G - TOC);
+      break;
+    case R_PPC64_PLT16_HA:
+      *(ul16 *)loc = ha(G + GOT - TOC);
+      break;
+    case R_PPC64_PLT16_HI:
+      *(ul16 *)loc = hi(G + GOT - TOC);
+      break;
+    case R_PPC64_PLT16_LO:
+      *(ul16 *)loc = lo(G + GOT - TOC);
+      break;
+    case R_PPC64_PLT16_LO_DS:
+      *(ul16 *)loc |= (G + GOT - TOC) & 0xfffc;
+      break;
+    case R_PPC64_PLT_PCREL34:
+    case R_PPC64_PLT_PCREL34_NOTOC:
+    case R_PPC64_GOT_PCREL34:
+      write34(loc, G + GOT - P);
+      break;
+    case R_PPC64_PCREL34:
+      write34(loc, S + A - P);
+      break;
+    case R_PPC64_GOT_TPREL16_HA:
+      *(ul16 *)loc = ha(sym.get_gottp_addr(ctx) - TOC);
+      break;
+    case R_PPC64_GOT_TPREL16_LO_DS:
+      *(ul16 *)loc |= (sym.get_gottp_addr(ctx) - TOC) & 0xfffc;
+      break;
+    case R_PPC64_GOT_TPREL_PCREL34:
+      write34(loc, sym.get_gottp_addr(ctx) - P);
+      break;
+    case R_PPC64_GOT_TLSGD16_HA:
+      *(ul16 *)loc = ha(sym.get_tlsgd_addr(ctx) - TOC);
+      break;
+    case R_PPC64_GOT_TLSGD16_LO:
+      *(ul16 *)loc = lo(sym.get_tlsgd_addr(ctx) - TOC);
+      break;
+    case R_PPC64_GOT_TLSGD_PCREL34:
+      write34(loc, sym.get_tlsgd_addr(ctx) - P);
+      break;
+    case R_PPC64_GOT_TLSLD16_HA:
+      *(ul16 *)loc = ha(ctx.got->get_tlsld_addr(ctx) - TOC);
+      break;
+    case R_PPC64_GOT_TLSLD16_LO:
+      *(ul16 *)loc = lo(ctx.got->get_tlsld_addr(ctx) - TOC);
+      break;
+    case R_PPC64_GOT_TLSLD_PCREL34:
+      write34(loc, ctx.got->get_tlsld_addr(ctx) - P);
+      break;
+    case R_PPC64_DTPREL16_HA:
+      *(ul16 *)loc = ha(S + A - ctx.dtp_addr);
+      break;
+    case R_PPC64_DTPREL16_LO:
+      *(ul16 *)loc = lo(S + A - ctx.dtp_addr);
+      break;
+    case R_PPC64_DTPREL16_LO_DS:
+      *(ul16 *)loc |= (S + A - ctx.dtp_addr) & 0xfffc;
+      break;
+    case R_PPC64_DTPREL34:
+      write34(loc, S + A - ctx.dtp_addr);
+      break;
+    case R_PPC64_TPREL16_HA:
+      *(ul16 *)loc = ha(S + A - ctx.tp_addr);
+      break;
+    case R_PPC64_TPREL16_LO:
+      *(ul16 *)loc = lo(S + A - ctx.tp_addr);
+      break;
+    case R_PPC64_TPREL16_LO_DS:
+      *(ul16 *)loc |= (S + A - ctx.tp_addr) & 0xfffc;
+      break;
+    case R_PPC64_TPREL34:
+      write34(loc, S + A - ctx.tp_addr);
+      break;
+    case R_PPC64_ADDR64:
+    case R_PPC64_PLTSEQ:
+    case R_PPC64_PLTSEQ_NOTOC:
+    case R_PPC64_PLTCALL:
+    case R_PPC64_PLTCALL_NOTOC:
+    case R_PPC64_TLS:
+    case R_PPC64_TLSGD:
+    case R_PPC64_TLSLD:
+    case R_PPC64_ENTRY:
+      break;
+    default:
+      unreachable();
+    }
+  }
+}
+
+template <>
+void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
+  std::span<const ElfRel<E>> rels = get_rels(ctx);
+
+  for (i64 i = 0; i < rels.size(); i++) {
+    const ElfRel<E> &rel = rels[i];
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
+      continue;
+
+    Symbol<E> &sym = *file.symbols[rel.r_sym];
+    u8 *loc = base + rel.r_offset;
+
+    SectionFragment<E> *frag;
+    i64 frag_addend;
+    std::tie(frag, frag_addend) = get_fragment(ctx, rel);
+
+    u64 S = frag ? frag->get_addr(ctx) : sym.get_addr(ctx);
+    u64 A = frag ? frag_addend : (i64)rel.r_addend;
+
+    auto check = [&](i64 val, i64 lo, i64 hi) {
+      check_range(ctx, i, val, lo, hi);
+    };
+
+    switch (rel.r_type) {
+    case R_PPC64_ADDR64:
+      if (std::optional<u64> val = get_tombstone(sym, frag))
+        *(ul64 *)loc = *val;
+      else
+        *(ul64 *)loc = S + A;
+      break;
+    case R_PPC64_ADDR32:
+      check(S + A, 0, 1LL << 32);
+      *(ul32 *)loc = S + A;
+      break;
+    case R_PPC64_DTPREL64:
+      *(ul64 *)loc = S + A - ctx.dtp_addr;
+      break;
+    default:
+      Fatal(ctx) << *this << ": invalid relocation for non-allocated sections: "
+                 << rel;
+    }
+  }
+}
+
+template <>
+void InputSection<E>::scan_relocations(Context<E> &ctx) {
+  assert(shdr().sh_flags & SHF_ALLOC);
+  std::span<const ElfRel<E>> rels = get_rels(ctx);
+
+  // Scan relocations
+  for (i64 i = 0; i < rels.size(); i++) {
+    const ElfRel<E> &rel = rels[i];
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
+      continue;
+
+    Symbol<E> &sym = *file.symbols[rel.r_sym];
+
+    if (sym.is_ifunc())
+      sym.flags |= NEEDS_GOT | NEEDS_PLT;
+
+    switch (rel.r_type) {
+    case R_PPC64_GOT_TPREL16_HA:
+    case R_PPC64_GOT_TPREL_PCREL34:
+      sym.flags |= NEEDS_GOTTP;
+      break;
+    case R_PPC64_REL24:
+      if (sym.is_imported)
+        sym.flags |= NEEDS_PLT;
+      break;
+    case R_PPC64_REL24_NOTOC:
+      if (sym.is_imported)
+        sym.flags |= NEEDS_PLT;
+      ctx.extra.is_power10 = true;
+      break;
+    case R_PPC64_GOT16:
+    case R_PPC64_GOT16_LO:
+    case R_PPC64_GOT16_HI:
+    case R_PPC64_GOT16_HA:
+    case R_PPC64_PLT16_HA:
+    case R_PPC64_PLT_PCREL34:
+    case R_PPC64_PLT_PCREL34_NOTOC:
+    case R_PPC64_GOT_PCREL34:
+      sym.flags |= NEEDS_GOT;
+      break;
+    case R_PPC64_GOT_TLSGD16_HA:
+    case R_PPC64_GOT_TLSGD_PCREL34:
+      sym.flags |= NEEDS_TLSGD;
+      break;
+    case R_PPC64_GOT_TLSLD16_HA:
+    case R_PPC64_GOT_TLSLD_PCREL34:
+      ctx.needs_tlsld = true;
+      break;
+    case R_PPC64_TPREL16_HA:
+    case R_PPC64_TPREL34:
+      check_tlsle(ctx, sym, rel);
+      break;
+    case R_PPC64_ADDR64:
+    case R_PPC64_REL14:
+    case R_PPC64_REL32:
+    case R_PPC64_REL64:
+    case R_PPC64_TOC16_HA:
+    case R_PPC64_TOC16_LO:
+    case R_PPC64_TOC16_LO_DS:
+    case R_PPC64_TOC16_DS:
+    case R_PPC64_REL16_HA:
+    case R_PPC64_REL16_LO:
+    case R_PPC64_PLT16_HI:
+    case R_PPC64_PLT16_LO:
+    case R_PPC64_PLT16_LO_DS:
+    case R_PPC64_PCREL34:
+    case R_PPC64_PLTSEQ:
+    case R_PPC64_PLTSEQ_NOTOC:
+    case R_PPC64_PLTCALL:
+    case R_PPC64_PLTCALL_NOTOC:
+    case R_PPC64_GOT_TPREL16_LO_DS:
+    case R_PPC64_GOT_TLSGD16_LO:
+    case R_PPC64_GOT_TLSLD16_LO:
+    case R_PPC64_TPREL16_LO:
+    case R_PPC64_TPREL16_LO_DS:
+    case R_PPC64_TLS:
+    case R_PPC64_TLSGD:
+    case R_PPC64_TLSLD:
+    case R_PPC64_DTPREL16_HA:
+    case R_PPC64_DTPREL16_LO:
+    case R_PPC64_DTPREL16_LO_DS:
+    case R_PPC64_DTPREL34:
+    case R_PPC64_ENTRY:
+      break;
+    default:
+      Error(ctx) << *this << ": unknown relocation: " << rel;
+    }
+  }
+}
+
+template <>
+void Thunk<E>::copy_buf(Context<E> &ctx) {
+  // If the destination is PLT, we read an address from .got.plt or .got
+  // and jump there.
+  constexpr ul32 plt_thunk[] = {
+    0xf841'0018, // std   r2, 24(r1)
+    0x6000'0000, // nop
+    0x3d82'0000, // addis r12, r2, foo@gotplt@toc@ha
+    0xe98c'0000, // ld    r12, foo@gotplt@toc@lo(r12)
+    0x7d89'03a6, // mtctr r12
+    0x4e80'0420, // bctr
+  };
+
+  constexpr ul32 plt_thunk_power10[] = {
+    0xf841'0018, // std   r2, 24(r1)
+    0x6000'0000, // nop
+    0x0410'0000, // pld   r12, foo@gotplt@pcrel
+    0xe580'0000,
+    0x7d89'03a6, // mtctr r12
+    0x4e80'0420, // bctr
+  };
+
+  // If the destination is a non-imported function, we directly jump
+  // to its local entry point.
+  constexpr ul32 local_thunk[] = {
+    0xf841'0018, // std   r2, 24(r1)
+    0x6000'0000, // nop
+    0x3d82'0000, // addis r12, r2,  foo@toc@ha
+    0x398c'0000, // addi  r12, r12, foo@toc@lo
+    0x7d89'03a6, // mtctr r12
+    0x4e80'0420, // bctr
+  };
+
+  constexpr ul32 local_thunk_power10[] = {
+    0xf841'0018, // std   r2, 24(r1)
+    0x6000'0000, // nop
+    0x0610'0000, // pla   r12, foo@pcrel
+    0x3980'0000,
+    0x7d89'03a6, // mtctr r12
+    0x4e80'0420, // bctr
+  };
+
+  static_assert(E::thunk_size == sizeof(plt_thunk));
+  static_assert(E::thunk_size == sizeof(plt_thunk_power10));
+  static_assert(E::thunk_size == sizeof(local_thunk));
+  static_assert(E::thunk_size == sizeof(local_thunk_power10));
+
+  u8 *base = ctx.buf + output_section.shdr.sh_offset + offset;
+  u64 TOC = ctx.extra.TOC->value;
+
+  for (i64 i = 0; i < symbols.size(); i++) {
+    Symbol<E> &sym = *symbols[i];
+    u64 P = get_addr() + offsets[i];
+    u8 *buf = base + offsets[i];
+
+    if (sym.has_plt(ctx)) {
+      u64 got = sym.has_got(ctx) ? sym.get_got_addr(ctx) : sym.get_gotplt_addr(ctx);
+      if (ctx.extra.is_power10) {
+        memcpy(buf, plt_thunk_power10, E::thunk_size);
+        write34(buf + 8, got - P - 8);
+      } else {
+        memcpy(buf, plt_thunk, E::thunk_size);
+        *(ul32 *)(buf + 8) |= higha(got - TOC);
+        *(ul32 *)(buf + 12) |= lo(got - TOC);
+      }
+    } else {
+      u64 S = sym.get_addr(ctx);
+      if (ctx.extra.is_power10) {
+        memcpy(buf, local_thunk_power10, E::thunk_size);
+        write34(buf + 8, S - P - 8);
+      } else {
+        memcpy(buf, local_thunk, E::thunk_size);
+        *(ul32 *)(buf + 8) |= higha(S - TOC);
+        *(ul32 *)(buf + 12) |= lo(S - TOC);
+      }
+    }
+  }
+}
+
+// GCC may emit references to the following functions in function prologue
+// and epiilogue if -Os is specified. For some reason, these functions are
+// not in libgcc.a and expected to be synthesized by the linker.
+const std::vector<std::pair<std::string_view, u32>>
+ppc64_save_restore_insns = {
+  { "_savegpr0_14", 0xf9c1ff70 }, // std r14,-144(r1)
+  { "_savegpr0_15", 0xf9e1ff78 }, // std r15,-136(r1)
+  { "_savegpr0_16", 0xfa01ff80 }, // std r16,-128(r1)
+  { "_savegpr0_17", 0xfa21ff88 }, // std r17,-120(r1)
+  { "_savegpr0_18", 0xfa41ff90 }, // std r18,-112(r1)
+  { "_savegpr0_19", 0xfa61ff98 }, // std r19,-104(r1)
+  { "_savegpr0_20", 0xfa81ffa0 }, // std r20,-96(r1)
+  { "_savegpr0_21", 0xfaa1ffa8 }, // std r21,-88(r1)
+  { "_savegpr0_22", 0xfac1ffb0 }, // std r22,-80(r1)
+  { "_savegpr0_23", 0xfae1ffb8 }, // std r23,-72(r1)
+  { "_savegpr0_24", 0xfb01ffc0 }, // std r24,-64(r1)
+  { "_savegpr0_25", 0xfb21ffc8 }, // std r25,-56(r1)
+  { "_savegpr0_26", 0xfb41ffd0 }, // std r26,-48(r1)
+  { "_savegpr0_27", 0xfb61ffd8 }, // std r27,-40(r1)
+  { "_savegpr0_28", 0xfb81ffe0 }, // std r28,-32(r1)
+  { "_savegpr0_29", 0xfba1ffe8 }, // std r29,-24(r1)
+  { "_savegpr0_30", 0xfbc1fff0 }, // std r30,-16(r1)
+  { "_savegpr0_31", 0xfbe1fff8 }, // std r31,-8(r1)
+  { "",             0xf8010010 }, // std r0,16(r1)
+  { "",             0x4e800020 }, // blr
+
+  { "_restgpr0_14", 0xe9c1ff70 }, // ld r14,-144(r1)
+  { "_restgpr0_15", 0xe9e1ff78 }, // ld r15,-136(r1)
+  { "_restgpr0_16", 0xea01ff80 }, // ld r16,-128(r1)
+  { "_restgpr0_17", 0xea21ff88 }, // ld r17,-120(r1)
+  { "_restgpr0_18", 0xea41ff90 }, // ld r18,-112(r1)
+  { "_restgpr0_19", 0xea61ff98 }, // ld r19,-104(r1)
+  { "_restgpr0_20", 0xea81ffa0 }, // ld r20,-96(r1)
+  { "_restgpr0_21", 0xeaa1ffa8 }, // ld r21,-88(r1)
+  { "_restgpr0_22", 0xeac1ffb0 }, // ld r22,-80(r1)
+  { "_restgpr0_23", 0xeae1ffb8 }, // ld r23,-72(r1)
+  { "_restgpr0_24", 0xeb01ffc0 }, // ld r24,-64(r1)
+  { "_restgpr0_25", 0xeb21ffc8 }, // ld r25,-56(r1)
+  { "_restgpr0_26", 0xeb41ffd0 }, // ld r26,-48(r1)
+  { "_restgpr0_27", 0xeb61ffd8 }, // ld r27,-40(r1)
+  { "_restgpr0_28", 0xeb81ffe0 }, // ld r28,-32(r1)
+  { "_restgpr0_29", 0xe8010010 }, // ld r0,16(r1)
+  { "",             0xeba1ffe8 }, // ld r29,-24(r1)
+  { "",             0x7c0803a6 }, // mtlr r0
+  { "",             0xebc1fff0 }, // ld r30,-16(r1)
+  { "",             0xebe1fff8 }, // ld r31,-8(r1)
+  { "",             0x4e800020 }, // blr
+  { "_restgpr0_30", 0xebc1fff0 }, // ld r30,-16(r1)
+  { "_restgpr0_31", 0xe8010010 }, // ld r0,16(r1)
+  { "",             0xebe1fff8 }, // ld r31,-8(r1)
+  { "",             0x7c0803a6 }, // mtlr r0
+  { "",             0x4e800020 }, // blr
+
+  { "_savegpr1_14", 0xf9ccff70 }, // std r14,-144(r12)
+  { "_savegpr1_15", 0xf9ecff78 }, // std r15,-136(r12)
+  { "_savegpr1_16", 0xfa0cff80 }, // std r16,-128(r12)
+  { "_savegpr1_17", 0xfa2cff88 }, // std r17,-120(r12)
+  { "_savegpr1_18", 0xfa4cff90 }, // std r18,-112(r12)
+  { "_savegpr1_19", 0xfa6cff98 }, // std r19,-104(r12)
+  { "_savegpr1_20", 0xfa8cffa0 }, // std r20,-96(r12)
+  { "_savegpr1_21", 0xfaacffa8 }, // std r21,-88(r12)
+  { "_savegpr1_22", 0xfaccffb0 }, // std r22,-80(r12)
+  { "_savegpr1_23", 0xfaecffb8 }, // std r23,-72(r12)
+  { "_savegpr1_24", 0xfb0cffc0 }, // std r24,-64(r12)
+  { "_savegpr1_25", 0xfb2cffc8 }, // std r25,-56(r12)
+  { "_savegpr1_26", 0xfb4cffd0 }, // std r26,-48(r12)
+  { "_savegpr1_27", 0xfb6cffd8 }, // std r27,-40(r12)
+  { "_savegpr1_28", 0xfb8cffe0 }, // std r28,-32(r12)
+  { "_savegpr1_29", 0xfbacffe8 }, // std r29,-24(r12)
+  { "_savegpr1_30", 0xfbccfff0 }, // std r30,-16(r12)
+  { "_savegpr1_31", 0xfbecfff8 }, // std r31,-8(r12)
+  { "",             0x4e800020 }, // blr
+
+  { "_restgpr1_14", 0xe9ccff70 }, // ld r14,-144(r12)
+  { "_restgpr1_15", 0xe9ecff78 }, // ld r15,-136(r12)
+  { "_restgpr1_16", 0xea0cff80 }, // ld r16,-128(r12)
+  { "_restgpr1_17", 0xea2cff88 }, // ld r17,-120(r12)
+  { "_restgpr1_18", 0xea4cff90 }, // ld r18,-112(r12)
+  { "_restgpr1_19", 0xea6cff98 }, // ld r19,-104(r12)
+  { "_restgpr1_20", 0xea8cffa0 }, // ld r20,-96(r12)
+  { "_restgpr1_21", 0xeaacffa8 }, // ld r21,-88(r12)
+  { "_restgpr1_22", 0xeaccffb0 }, // ld r22,-80(r12)
+  { "_restgpr1_23", 0xeaecffb8 }, // ld r23,-72(r12)
+  { "_restgpr1_24", 0xeb0cffc0 }, // ld r24,-64(r12)
+  { "_restgpr1_25", 0xeb2cffc8 }, // ld r25,-56(r12)
+  { "_restgpr1_26", 0xeb4cffd0 }, // ld r26,-48(r12)
+  { "_restgpr1_27", 0xeb6cffd8 }, // ld r27,-40(r12)
+  { "_restgpr1_28", 0xeb8cffe0 }, // ld r28,-32(r12)
+  { "_restgpr1_29", 0xebacffe8 }, // ld r29,-24(r12)
+  { "_restgpr1_30", 0xebccfff0 }, // ld r30,-16(r12)
+  { "_restgpr1_31", 0xebecfff8 }, // ld r31,-8(r12)
+  { "",             0x4e800020 }, // blr
+};
+
+void PPC64SaveRestoreSection::copy_buf(Context<E> &ctx) {
+  ul32 *buf = (ul32 *)(ctx.buf + this->shdr.sh_offset);
+  for (auto [label, insn] : ppc64_save_restore_insns)
+    *buf++ = insn;
+}
+
+template <>
+u64 get_eflags(Context<E> &ctx) {
+  return 2;
+}
+
+} // namespace mold
+
+#endif

src/arch-s390x.cc

@@ -33,11 +33,13 @@
 // we need to add TP to a return value before use. I don't know why it is
 // different, but that is the way it is.
 //
-// https://github.com/rui314/psabi/blob/main/s390x.pdf
+// https://github.com/IBM/s390x-abi/releases/download/v1.6.1/lzsabi_s390x.pdf
+
+#if MOLD_S390X
 
 #include "mold.h"
 
-namespace mold::elf {
+namespace mold {
 
 using E = S390X;
 
@@ -48,16 +50,29 @@ static void write_mid20(u8 *loc, u64 val) {
 template <>
 void write_plt_header(Context<E> &ctx, u8 *buf) {
   static u8 insn[] = {
+    // Compute the offset into .rela.plt. This is equivalent to
+    // (%r0 - %r1 - 48 - 14) * 3/2 where %r0 is the PLT entry address
+    // plus 14, %r1 is the start address of .plt, and 48 is the size
+    // of this PLT header. We multiply by 3/2 because each PLT entry
+    // is 16 bytes, whereas each .rela.plt entry is 24 bytes.
+    0xb9, 0x09, 0x00, 0x01,             // sgr   %r0, %r1
+    0xa7, 0x0b, 0xff, 0xc2,             // aghi  %r0, -62
+    0xeb, 0x10, 0x00, 0x01, 0x00, 0x0c, // srlg  %r1, %r0, 1
+    0xb9, 0x08, 0x00, 0x01,             // agr   %r0, %r1
+    // Store the computed value to 56(%r15) and .got.plt[1] to 48(%15)
+    // where %r15 is the stack pointer.
     0xe3, 0x00, 0xf0, 0x38, 0x00, 0x24, // stg   %r0, 56(%r15)
     0xc0, 0x10, 0, 0, 0, 0,             // larl  %r1, GOTPLT_OFFSET
     0xd2, 0x07, 0xf0, 0x30, 0x10, 0x08, // mvc   48(8, %r15), 8(%r1)
+    // Branch to _dl_runtime_resolve
     0xe3, 0x10, 0x10, 0x10, 0x00, 0x04, // lg    %r1, 16(%r1)
     0x07, 0xf1,                         // br    %r1
-    0x07, 0x00, 0x07, 0x00, 0x07, 0x00, // nopr; nopr; nopr
+    0x00, 0x00, 0x00, 0x00,             // (filler)
   };
 
   memcpy(buf, insn, sizeof(insn));
-  *(ub32 *)(buf + 8) = (ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 6) >> 1;
+  *(ub32 *)(buf + 26) =
+    (ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 24) >> 1;
 }
 
 template <>
@@ -65,15 +80,12 @@ void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
   static u8 insn[] = {
     0xc0, 0x10, 0, 0, 0, 0,             // larl  %r1, GOTPLT_ENTRY_OFFSET
     0xe3, 0x10, 0x10, 0x00, 0x00, 0x04, // lg    %r1, (%r1)
-    0xc0, 0x01, 0, 0, 0, 0,             // lgfi  %r0, PLT_INDEX
-    0x07, 0xf1,                         // br    %r1
-    0x07, 0x00, 0x07, 0x00, 0x07, 0x00, // nopr; nopr; nopr
-    0x07, 0x00, 0x07, 0x00, 0x07, 0x00, // nopr; nopr; nopr
+    0x0d, 0x01,                         // basr  %r0, %r1
+    0x00, 0x00,                         // (filler)
   };
 
   memcpy(buf, insn, sizeof(insn));
   *(ub32 *)(buf + 2) = (sym.get_gotplt_addr(ctx) - sym.get_plt_addr(ctx)) >> 1;
-  *(ub32 *)(buf + 14) = sym.get_plt_idx(ctx) * sizeof(ElfRel<E>);
 }
 
 template <>
@@ -82,16 +94,16 @@ void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
     0xc0, 0x10, 0, 0, 0, 0,             // larl  %r1, GOT_ENTRY_OFFSET
     0xe3, 0x10, 0x10, 0x00, 0x00, 0x04, // lg    %r1, (%r1)
     0x07, 0xf1,                         // br    %r1
-    0x07, 0x00,                         // nopr
+    0x00, 0x00,                         // (filler)
   };
 
   memcpy(buf, insn, sizeof(insn));
-  *(ub32 *)(buf + 2) = (sym.get_got_addr(ctx) - sym.get_plt_addr(ctx)) >> 1;
+  *(ub32 *)(buf + 2) = (sym.get_got_pltgot_addr(ctx) - sym.get_plt_addr(ctx)) >> 1;
 }
 
 template <>
-void EhFrameSection<E>::apply_reloc(Context<E> &ctx, const ElfRel<E> &rel,
-                                    u64 offset, u64 val) {
+void EhFrameSection<E>::apply_eh_reloc(Context<E> &ctx, const ElfRel<E> &rel,
+                                       u64 offset, u64 val) {
   u8 *loc = ctx.buf + this->shdr.sh_offset + offset;
 
   switch (rel.r_type) {
@@ -112,11 +124,6 @@ template <>
 void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
   std::span<const ElfRel<E>> rels = get_rels(ctx);
 
-  ElfRel<E> *dynrel = nullptr;
-  if (ctx.reldyn)
-    dynrel = (ElfRel<E> *)(ctx.buf + ctx.reldyn->shdr.sh_offset +
-                           file.reldyn_offset + this->reldyn_offset);
-
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
     if (rel.r_type == R_NONE)
@@ -125,31 +132,26 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
     Symbol<E> &sym = *file.symbols[rel.r_sym];
     u8 *loc = base + rel.r_offset;
 
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
-    auto check_dbl = [&](i64 val, i64 lo, i64 hi) {
-      check(val, lo, hi);
-
-      // R_390_*DBL relocs should never refer a symbol at an odd address
-      if (val & 1)
-        Error(ctx) << *this << ": misaligned symbol " << sym
-                   << " for relocation " << rel;
-    };
-
     u64 S = sym.get_addr(ctx);
     u64 A = rel.r_addend;
     u64 P = get_addr() + rel.r_offset;
     u64 G = sym.get_got_idx(ctx) * sizeof(Word<E>);
     u64 GOT = ctx.got->shdr.sh_addr;
 
+    auto check = [&](i64 val, i64 lo, i64 hi) {
+      check_range(ctx, i, val, lo, hi);
+    };
+
+    auto check_dbl = [&](i64 val, i64 lo, i64 hi) {
+      // R_390_*DBL relocs should never refer to a symbol at an odd address
+      check(val, lo, hi);
+      if (val & 1)
+        Error(ctx) << *this << ": misaligned symbol " << sym
+                   << " for relocation " << rel;
+    };
+
     switch (rel.r_type) {
     case R_390_64:
-      apply_dyn_absrel(ctx, sym, rel, loc, S, A, P, dynrel);
       break;
     case R_390_8:
       check(S + A, 0, 1 << 8);
@@ -172,9 +174,6 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
       check(S + A, 0, 1LL << 32);
       *(ub32 *)loc = S + A;
       break;
-    case R_390_PLT64:
-      *(ub64 *)loc = S + A;
-      break;
     case R_390_PC12DBL:
     case R_390_PLT12DBL:
       check_dbl(S + A - P, -(1 << 12), 1 << 12);
@@ -189,6 +188,7 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
       *(ub32 *)loc = S + A - P;
       break;
     case R_390_PC64:
+    case R_390_PLT64:
       *(ub64 *)loc = S + A - P;
       break;
     case R_390_PC16DBL:
@@ -252,7 +252,20 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
       *(ub32 *)loc = (GOT + A - P) >> 1;
       break;
     case R_390_GOTENT:
-      check(GOT + G + A - P, -(1LL << 32), 1LL << 32);
+      // If we can relax a GOT-loading LGRL to an address-materializing
+      // LARL, do that. The format of LGRL is 0xc 0x4 <reg> 0x8 followed
+      // by a 32-bit offset. LARL is 0xc 0x0 <reg> 0x0.
+      if (ctx.arg.relax && sym.is_pcrel_linktime_const(ctx)) {
+        u64 op = *(ub16 *)(loc - 2);
+        u64 val = S + A - P;
+        if ((op & 0xff0f) == 0xc408 && A == 2 && (val & 1) == 0 &&
+            is_int(val, 33)) {
+          *(ub16 *)(loc - 2) = 0xc000 | (op & 0x00f0);
+          *(ub32 *)loc = val >> 1;
+          break;
+        }
+      }
+      check_dbl(GOT + G + A - P, -(1LL << 32), 1LL << 32);
       *(ub32 *)loc = (GOT + G + A - P) >> 1;
       break;
     case R_390_TLS_LE32:
@@ -299,22 +312,14 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
     case R_390_TLS_LDM32:
       if (ctx.got->has_tlsld(ctx))
         *(ub32 *)loc = ctx.got->get_tlsld_addr(ctx) + A - GOT;
+      else
+        *(ub32 *)loc = ctx.dtp_addr - ctx.tp_addr;
       break;
     case R_390_TLS_LDM64:
       if (ctx.got->has_tlsld(ctx))
         *(ub64 *)loc = ctx.got->get_tlsld_addr(ctx) + A - GOT;
-      break;
-    case R_390_TLS_LDO32:
-      if (ctx.got->has_tlsld(ctx))
-        *(ub32 *)loc = S + A - ctx.dtp_addr;
       else
-        *(ub32 *)loc = S + A - ctx.tp_addr;
-      break;
-    case R_390_TLS_LDO64:
-      if (ctx.got->has_tlsld(ctx))
-        *(ub64 *)loc = S + A - ctx.dtp_addr;
-      else
-        *(ub64 *)loc = S + A - ctx.tp_addr;
+        *(ub64 *)loc = ctx.dtp_addr - ctx.tp_addr;
       break;
     case R_390_TLS_LDCALL:
       if (!ctx.got->has_tlsld(ctx)) {
@@ -323,6 +328,12 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
         memcpy(loc, insn, sizeof(insn));
       }
       break;
+    case R_390_TLS_LDO32:
+      *(ub32 *)loc = S + A - ctx.dtp_addr;
+      break;
+    case R_390_TLS_LDO64:
+      *(ub64 *)loc = S + A - ctx.dtp_addr;
+      break;
     default:
       unreachable();
     }
@@ -335,25 +346,12 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
     u8 *loc = base + rel.r_offset;
 
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
     SectionFragment<E> *frag;
     i64 frag_addend;
     std::tie(frag, frag_addend) = get_fragment(ctx, rel);
@@ -361,13 +359,15 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
     u64 S = frag ? frag->get_addr(ctx) : sym.get_addr(ctx);
     u64 A = frag ? frag_addend : (i64)rel.r_addend;
 
+    auto check = [&](i64 val, i64 lo, i64 hi) {
+      check_range(ctx, val, i, lo, hi);
+    };
+
     switch (rel.r_type) {
-    case R_390_32: {
-      i64 val = S + A;
-      check(val, 0, 1LL << 32);
-      *(ub32 *)loc = val;
+    case R_390_32:
+      check(S + A, 0, 1LL << 32);
+      *(ub32 *)loc = S + A;
       break;
-    }
     case R_390_64:
       if (std::optional<u64> val = get_tombstone(sym, frag))
         *(ub64 *)loc = *val;
@@ -389,31 +389,20 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 template <>
 void InputSection<E>::scan_relocations(Context<E> &ctx) {
   assert(shdr().sh_flags & SHF_ALLOC);
-
-  this->reldyn_offset = file.num_dynrel * sizeof(ElfRel<E>);
   std::span<const ElfRel<E>> rels = get_rels(ctx);
 
   // Scan relocations
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
 
     if (sym.is_ifunc())
       sym.flags |= NEEDS_GOT | NEEDS_PLT;
 
     switch (rel.r_type) {
-    case R_390_64:
-      scan_dyn_absrel(ctx, sym, rel);
-      break;
     case R_390_8:
     case R_390_12:
     case R_390_16:
@@ -421,8 +410,10 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
     case R_390_32:
       scan_absrel(ctx, sym, rel);
       break;
+    case R_390_PC12DBL:
     case R_390_PC16:
     case R_390_PC16DBL:
+    case R_390_PC24DBL:
     case R_390_PC32:
     case R_390_PC32DBL:
     case R_390_PC64:
@@ -467,36 +458,38 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
       // We always want to relax calls to __tls_get_offset() in statically-
       // linked executables because __tls_get_offset() in libc.a just calls
       // abort().
-      if (ctx.arg.is_static ||
-          (ctx.arg.relax && !sym.is_imported && !ctx.arg.shared)) {
-        // do nothing
-      } else if (ctx.arg.relax && !sym.is_imported && ctx.arg.shared &&
-                 !ctx.arg.z_dlopen) {
+      if (ctx.arg.static_ || (ctx.arg.relax && sym.is_tprel_linktime_const(ctx))) {
+        // Do nothing
+      } else if (ctx.arg.relax && sym.is_tprel_runtime_const(ctx)) {
         sym.flags |= NEEDS_GOTTP;
       } else {
         sym.flags |= NEEDS_TLSGD;
       }
       break;
     case R_390_TLS_LDM32:
-    case R_390_TLS_LDM64: {
-      bool do_relax = ctx.arg.is_static || (ctx.arg.relax && !ctx.arg.shared);
-      if (!do_relax)
+    case R_390_TLS_LDM64:
+      if (ctx.arg.static_ || (ctx.arg.relax && !ctx.arg.shared)) {
+        // Do nothing
+      } else {
         ctx.needs_tlsld = true;
+      }
       break;
-    }
     case R_390_TLS_LE32:
     case R_390_TLS_LE64:
       check_tlsle(ctx, sym, rel);
       break;
+    case R_390_64:
     case R_390_TLS_LDO32:
     case R_390_TLS_LDO64:
     case R_390_TLS_GDCALL:
     case R_390_TLS_LDCALL:
       break;
     default:
-      Fatal(ctx) << *this << ": scan_relocations: " << rel;
+      Error(ctx) << *this << ": unknown relocation: " << rel;
     }
   }
 }
 
-} // namespace mold::elf
+} // namespace mold
+
+#endif

src/arch-sh4.cc

@@ -58,11 +58,13 @@
 //    output from the linker contains lots of text relocations. That's not
 //    a problem with embedded programming, I guess.
 
+#if MOLD_SH4LE || MOLD_SH4BE
+
 #include "mold.h"
 
-namespace mold::elf {
+namespace mold {
 
-using E = SH4;
+using E = MOLD_TARGET;
 
 // Even though SH-4 uses RELA-type relocations, addends are stored to
 // relocated places for some reason.
@@ -84,120 +86,142 @@ i64 get_addend(u8 *loc, const ElfRel<E> &rel) {
   case R_SH_GOTOFF:
   case R_SH_GOTPC:
   case R_SH_GOTPLT32:
-    return *(ul32 *)loc;
+    return *(U32<E> *)loc;
   default:
     return 0;
   }
 }
 
+template <>
+void write_addend(u8 *loc, i64 val, const ElfRel<E> &rel) {
+  switch (rel.r_type) {
+  case R_SH_DIR32:
+  case R_SH_REL32:
+  case R_SH_TLS_GD_32:
+  case R_SH_TLS_LD_32:
+  case R_SH_TLS_LDO_32:
+  case R_SH_TLS_IE_32:
+  case R_SH_TLS_LE_32:
+  case R_SH_TLS_DTPMOD32:
+  case R_SH_TLS_DTPOFF32:
+  case R_SH_TLS_TPOFF32:
+  case R_SH_GOT32:
+  case R_SH_PLT32:
+  case R_SH_GOTOFF:
+  case R_SH_GOTPC:
+  case R_SH_GOTPLT32:
+    *(U32<E> *)loc = val;
+  }
+}
+
 template <>
 void write_plt_header(Context<E> &ctx, u8 *buf) {
   if (ctx.arg.pic) {
-    static const u8 insn[] = {
-      0x02, 0xd2, //    mov.l   1f, r2
-      0xcc, 0x32, //    add     r12, r2
-      0x22, 0x50, //    mov.l   @(8, r2), r0
-      0x21, 0x52, //    mov.l   @(4, r2), r2
-      0x2b, 0x40, //    jmp     @r0
-      0x00, 0xe0, //    mov     #0, r0
-      0, 0, 0, 0, // 1: .long GOTPLT
+    constexpr U16<E> insn[] = {
+      0xd202, //    mov.l   1f, r2
+      0x32cc, //    add     r12, r2
+      0x5022, //    mov.l   @(8, r2), r0
+      0x5221, //    mov.l   @(4, r2), r2
+      0x402b, //    jmp     @r0
+      0xe000, //    mov     #0, r0
+      0, 0,   // 1: .long GOTPLT
     };
 
     static_assert(sizeof(insn) == E::plt_hdr_size);
     memcpy(buf, insn, sizeof(insn));
-    *(ul32 *)(buf + 12) = ctx.gotplt->shdr.sh_addr - ctx.got->shdr.sh_addr;
+    *(U32<E> *)(buf + 12) = ctx.gotplt->shdr.sh_addr - ctx.got->shdr.sh_addr;
   } else {
-    static const u8 insn[] = {
-      0x02, 0xd2, //    mov.l   1f, r2
-      0x22, 0x50, //    mov.l   @(8, r2), r0
-      0x21, 0x52, //    mov.l   @(4, r2), r2
-      0x2b, 0x40, //    jmp     @r0
-      0x00, 0xe0, //    mov     #0, r0
-      0x09, 0x00, //    nop
-      0, 0, 0, 0, // 1: .long GOTPLT
+    constexpr U16<E> insn[] = {
+      0xd202, //    mov.l   1f, r2
+      0x5022, //    mov.l   @(8, r2), r0
+      0x5221, //    mov.l   @(4, r2), r2
+      0x402b, //    jmp     @r0
+      0xe000, //    mov     #0, r0
+      0xfffd, //    (illegal)
+      0, 0,   // 1: .long GOTPLT
     };
 
     static_assert(sizeof(insn) == E::plt_hdr_size);
     memcpy(buf, insn, sizeof(insn));
-    *(ul32 *)(buf + 12) = ctx.gotplt->shdr.sh_addr;
+    *(U32<E> *)(buf + 12) = ctx.gotplt->shdr.sh_addr;
   }
 }
 
 template <>
 void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
   if (ctx.arg.pic) {
-    static const u8 insn[] = {
-      0x01, 0xd0, //    mov.l   1f, r0
-      0xce, 0x00, //    mov.l   @(r0, r12), r0
-      0x2b, 0x40, //    jmp     @r0
-      0x01, 0xd1, //    mov.l   2f, r1
-      0, 0, 0, 0, // 1: .long GOTPLT_ENTRY
-      0, 0, 0, 0, // 2: .long INDEX_IN_RELPLT
+    constexpr U16<E> insn[] = {
+      0xd001, //    mov.l   1f, r0
+      0x00ce, //    mov.l   @(r0, r12), r0
+      0x402b, //    jmp     @r0
+      0xd101, //    mov.l   2f, r1
+      0, 0,   // 1: .long GOTPLT_ENTRY
+      0, 0,   // 2: .long INDEX_IN_RELPLT
     };
 
     static_assert(sizeof(insn) == E::plt_size);
     memcpy(buf, insn, sizeof(insn));
-    *(ul32 *)(buf + 8) = sym.get_gotplt_addr(ctx) - ctx.got->shdr.sh_addr;
-    *(ul32 *)(buf + 12) = sym.get_plt_idx(ctx) * sizeof(ElfRel<E>);
+    *(U32<E> *)(buf + 8) = sym.get_gotplt_addr(ctx) - ctx.got->shdr.sh_addr;
+    *(U32<E> *)(buf + 12) = sym.get_plt_idx(ctx) * sizeof(ElfRel<E>);
   } else {
-    static const u8 insn[] = {
-      0x01, 0xd0, //    mov.l   1f, r0
-      0x02, 0x60, //    mov.l   @r0, r0
-      0x2b, 0x40, //    jmp     @r0
-      0x01, 0xd1, //    mov.l   2f, r1
-      0, 0, 0, 0, // 1: .long GOTPLT_ENTRY
-      0, 0, 0, 0, // 2: .long INDEX_IN_RELPLT
+    constexpr U16<E> insn[] = {
+      0xd001, //    mov.l   1f, r0
+      0x6002, //    mov.l   @r0, r0
+      0x402b, //    jmp     @r0
+      0xd101, //    mov.l   2f, r1
+      0, 0,   // 1: .long GOTPLT_ENTRY
+      0, 0,   // 2: .long INDEX_IN_RELPLT
     };
 
     static_assert(sizeof(insn) == E::plt_size);
     memcpy(buf, insn, sizeof(insn));
-    *(ul32 *)(buf + 8) = sym.get_gotplt_addr(ctx);
-    *(ul32 *)(buf + 12) = sym.get_plt_idx(ctx) * sizeof(ElfRel<E>);
+    *(U32<E> *)(buf + 8) = sym.get_gotplt_addr(ctx);
+    *(U32<E> *)(buf + 12) = sym.get_plt_idx(ctx) * sizeof(ElfRel<E>);
   }
 }
 
 template <>
 void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
   if (ctx.arg.pic) {
-    static const u8 insn[] = {
-      0x01, 0xd0, //    mov.l   1f, r0
-      0xce, 0x00, //    mov.l   @(r0, r12), r0
-      0x2b, 0x40, //    jmp     @r0
-      0x09, 0x00, //    nop
-      0, 0, 0, 0, // 1: .long GOT_ENTRY
+    constexpr U16<E> insn[] = {
+      0xd001, //    mov.l   1f, r0
+      0x00ce, //    mov.l   @(r0, r12), r0
+      0x402b, //    jmp     @r0
+      0x0009, //    nop
+      0, 0,   // 1: .long GOT_ENTRY
     };
 
     static_assert(sizeof(insn) == E::pltgot_size);
     memcpy(buf, insn, sizeof(insn));
-    *(ul32 *)(buf + 8) = sym.get_got_addr(ctx) - ctx.got->shdr.sh_addr;
+    *(U32<E> *)(buf + 8) = sym.get_got_pltgot_addr(ctx) - ctx.got->shdr.sh_addr;
   } else {
-    static const u8 insn[] = {
-      0x01, 0xd0, //    mov.l   1f, r0
-      0x02, 0x60, //    mov.l   @r0, r0
-      0x2b, 0x40, //    jmp     @r0
-      0x09, 0x00, //    nop
-      0, 0, 0, 0, // 1: .long GOT_ENTRY
+    constexpr U16<E> insn[] = {
+      0xd001, //    mov.l   1f, r0
+      0x6002, //    mov.l   @r0, r0
+      0x402b, //    jmp     @r0
+      0x0009, //    nop
+      0, 0,   // 1: .long GOT_ENTRY
     };
 
     static_assert(sizeof(insn) == E::pltgot_size);
     memcpy(buf, insn, sizeof(insn));
-    *(ul32 *)(buf + 8) = sym.get_got_addr(ctx);
+    *(U32<E> *)(buf + 8) = sym.get_got_pltgot_addr(ctx);
   }
 }
 
 template <>
-void EhFrameSection<E>::apply_reloc(Context<E> &ctx, const ElfRel<E> &rel,
-                                    u64 offset, u64 val) {
+void EhFrameSection<E>::apply_eh_reloc(Context<E> &ctx, const ElfRel<E> &rel,
+                                       u64 offset, u64 val) {
   u8 *loc = ctx.buf + this->shdr.sh_offset + offset;
 
   switch (rel.r_type) {
   case R_NONE:
     break;
   case R_SH_DIR32:
-    *(ul32 *)loc = val;
+    *(U32<E> *)loc = val;
     break;
   case R_SH_REL32:
-    *(ul32 *)loc = val - this->shdr.sh_addr - offset;
+    *(U32<E> *)loc = val - this->shdr.sh_addr - offset;
     break;
   default:
     Fatal(ctx) << "unsupported relocation in .eh_frame: " << rel;
@@ -208,11 +232,6 @@ template <>
 void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
   std::span<const ElfRel<E>> rels = get_rels(ctx);
 
-  ElfRel<E> *dynrel = nullptr;
-  if (ctx.reldyn)
-    dynrel = (ElfRel<E> *)(ctx.buf + ctx.reldyn->shdr.sh_offset +
-                           file.reldyn_offset + this->reldyn_offset);
-
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
     if (rel.r_type == R_NONE)
@@ -229,35 +248,34 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
 
     switch (rel.r_type) {
     case R_SH_DIR32:
-      apply_dyn_absrel(ctx, sym, rel, loc, S, A, P, dynrel);
       break;
     case R_SH_REL32:
     case R_SH_PLT32:
-      *(ul32 *)loc = S + A - P;
+      *(U32<E> *)loc = S + A - P;
       break;
     case R_SH_GOT32:
-      *(ul32 *)loc = G;
+      *(U32<E> *)loc = G;
       break;
     case R_SH_GOTPC:
-      *(ul32 *)loc = GOT + A - P;
+      *(U32<E> *)loc = GOT + A - P;
       break;
     case R_SH_GOTOFF:
-      *(ul32 *)loc = S + A - GOT;
+      *(U32<E> *)loc = S + A - GOT;
       break;
     case R_SH_TLS_GD_32:
-      *(ul32 *)loc = sym.get_tlsgd_addr(ctx) + A - GOT;
+      *(U32<E> *)loc = sym.get_tlsgd_addr(ctx) + A - GOT;
       break;
     case R_SH_TLS_LD_32:
-      *(ul32 *)loc = ctx.got->get_tlsld_addr(ctx) + A - GOT;
+      *(U32<E> *)loc = ctx.got->get_tlsld_addr(ctx) + A - GOT;
       break;
     case R_SH_TLS_LDO_32:
-      *(ul32 *)loc = S + A - ctx.dtp_addr;
+      *(U32<E> *)loc = S + A - ctx.dtp_addr;
       break;
     case R_SH_TLS_IE_32:
-      *(ul32 *)loc = sym.get_gottp_addr(ctx) + A - GOT;
+      *(U32<E> *)loc = sym.get_gottp_addr(ctx) + A - GOT;
       break;
     case R_SH_TLS_LE_32:
-      *(ul32 *)loc = S + A - ctx.tp_addr;
+      *(U32<E> *)loc = S + A - ctx.tp_addr;
       break;
     default:
       unreachable();
@@ -271,18 +289,12 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
     u8 *loc = base + rel.r_offset;
 
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
     SectionFragment<E> *frag;
     i64 frag_addend;
     std::tie(frag, frag_addend) = get_fragment(ctx, rel);
@@ -293,9 +305,9 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
     switch (rel.r_type) {
     case R_SH_DIR32:
       if (std::optional<u64> val = get_tombstone(sym, frag))
-        *(ul32 *)loc = *val;
+        *(U32<E> *)loc = *val;
       else
-        *(ul32 *)loc = S + A;
+        *(U32<E> *)loc = S + A;
       break;
     default:
       Fatal(ctx) << *this << ": invalid relocation for non-allocated sections: "
@@ -307,30 +319,19 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 template <>
 void InputSection<E>::scan_relocations(Context<E> &ctx) {
   assert(shdr().sh_flags & SHF_ALLOC);
-
-  this->reldyn_offset = file.num_dynrel * sizeof(ElfRel<E>);
   std::span<const ElfRel<E>> rels = get_rels(ctx);
 
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
 
     if (sym.is_ifunc())
       Error(ctx) << sym << ": GNU ifunc symbol is not supported on sh4";
 
     switch (rel.r_type) {
-    case R_SH_DIR32:
-      scan_dyn_absrel(ctx, sym, rel);
-      break;
     case R_SH_REL32:
       scan_pcrel(ctx, sym, rel);
       break;
@@ -353,6 +354,7 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
     case R_SH_TLS_LE_32:
       check_tlsle(ctx, sym, rel);
       break;
+    case R_SH_DIR32:
     case R_SH_GOTPC:
     case R_SH_GOTOFF:
     case R_SH_TLS_LDO_32:
@@ -363,4 +365,6 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
   }
 }
 
-} // namespace mold::elf
+} // namespace mold
+
+#endif

src/arch-sparc64.cc

@@ -51,14 +51,13 @@
 // address. That also means each function needs to execute the above piece
 // of code to become position-independent.
 //
-// This scheme is very similar to i386. That may not be a coincidence
-// because the i386 ELF psABI is created by Sun Microsystems too.
-//
 // https://github.com/rui314/psabi/blob/main/sparc.pdf
 
+#if MOLD_SPARC64
+
 #include "mold.h"
 
-namespace mold::elf {
+namespace mold {
 
 using E = SPARC64;
 
@@ -79,26 +78,77 @@ void write_plt_header(Context<E> &ctx, u8 *buf) {
   memset(buf, 0, E::plt_hdr_size);
 }
 
+// Returns the byte offset within .plt of the data pointer for a large SPARC
+// PLT entry. See write_plt_entry below for the block layout this assumes.
+i64 sparc_plt_ptr_offset(Context<E> &ctx, i64 pltidx) {
+  i64 i = pltidx - sparc_num_small_plt;
+  i64 block = i / 160;
+  i64 nlarge = (i64)ctx.plt->symbols.size() - sparc_num_small_plt;
+  i64 nstub = std::min<i64>(160, nlarge - block * 160);
+  return 0x100000 + block * 5120 + nstub * 24 + (i % 160) * 8;
+}
+
 template <>
 void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
-  static ub32 insn[] = {
-    0x0300'0000, // sethi (. - .PLT0), %g1
-    0x3068'0000, // ba,a  %xcc, .PLT1
-    0x0100'0000, // nop
-    0x0100'0000, // nop
-    0x0100'0000, // nop
-    0x0100'0000, // nop
-    0x0100'0000, // nop
-    0x0100'0000, // nop
-  };
+  // SPARC uses two PLT entry formats. A "small" entry branches directly to
+  // the resolver stub (.PLT1) with a BPcc instruction whose reach is only
+  // ±1 MiB. Once the PLT grows past that (0x100000 bytes), we switch to a
+  // "large" format: rather than branching to the resolver, a large entry
+  // loads a 64-bit value from a nearby data pointer and jumps to (that value
+  // + its own address).
+  //
+  // Large entries are grouped into blocks of 160: each block is 160 code
+  // stubs followed by 160 8-byte data pointers, one per stub. The stubs must
+  // sit on a fixed grid, 24 bytes apart, because that is how the loader finds
+  // them: on a lazy bind the stub jumps to the resolver (.PLT0) with only its
+  // own address, and the loader derives which symbol to resolve from that
+  // address. Nothing may sit between two stubs, so each stub's pointer lives
+  // in the block's pointer region, which it reaches with a signed 13-bit ldx
+  // offset (see to_plt_offset). This layout is dictated by the loader; we
+  // cannot rearrange or simplify it.
+  i64 idx = sym.get_plt_idx(ctx);
 
-  u64 plt0 = ctx.plt->shdr.sh_addr;
-  u64 plt1 = ctx.plt->shdr.sh_addr + E::plt_size;
-  u64 entry = sym.get_plt_addr(ctx);
+  if (idx < sparc_num_small_plt) {
+    static ub32 insn[] = {
+      0x0300'0000, // sethi (. - .PLT0), %g1
+      0x3068'0000, // ba,a  %xcc, .PLT1
+      0x0100'0000, // nop
+      0x0100'0000, // nop
+      0x0100'0000, // nop
+      0x0100'0000, // nop
+      0x0100'0000, // nop
+      0x0100'0000, // nop
+    };
 
-  memcpy(buf, insn, sizeof(insn));
-  *(ub32 *)buf |= bits(entry - plt0, 21, 0);
-  *(ub32 *)(buf + 4) |= bits(plt1 - entry - 4, 20, 2);
+    u64 plt0 = ctx.plt->shdr.sh_addr;
+    u64 plt1 = ctx.plt->shdr.sh_addr + E::plt_size;
+    u64 entry = sym.get_plt_addr(ctx);
+
+    memcpy(buf, insn, sizeof(insn));
+    *(ub32 *)buf |= bits(entry - plt0, 21, 0);
+    *(ub32 *)(buf + 4) |= bits(plt1 - entry - 4, 20, 2);
+  } else {
+    static ub32 insn[] = {
+      0x8a10'000f, // mov  %o7, %g5
+      0x4000'0002, // call . + 8
+      0x0100'0000, // nop
+      0xc25b'e000, // ldx  [ %o7 + .ptr ], %g1
+      0x83c3'c001, // jmpl %o7 + %g1, %g1
+      0x9e10'0005, // mov  %g5, %o7
+    };
+
+    u64 plt = ctx.plt->shdr.sh_addr;
+    u64 call = sym.get_plt_addr(ctx) + 4;
+    i64 ptroff = sparc_plt_ptr_offset(ctx, idx);
+
+    memcpy(buf, insn, sizeof(insn));
+    *(ub32 *)(buf + 12) |= bits(plt + ptroff - call, 12, 0);
+
+    // The data pointer initially holds (.PLT0 - call) so that the first call
+    // jumps to .PLT0, where the loader's lazy resolver lives. The resolver
+    // later overwrites it with (target - call).
+    *(ub64 *)(ctx.buf + ctx.plt->shdr.sh_offset + ptroff) = plt - call;
+  }
 }
 
 template <>
@@ -115,12 +165,12 @@ void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
   };
 
   memcpy(buf, entry, sizeof(entry));
-  *(ub64 *)(buf + 24) = sym.get_got_addr(ctx) - sym.get_plt_addr(ctx) - 4;
+  *(ub64 *)(buf + 24) = sym.get_got_pltgot_addr(ctx) - sym.get_plt_addr(ctx) - 4;
 }
 
 template <>
-void EhFrameSection<E>::apply_reloc(Context<E> &ctx, const ElfRel<E> &rel,
-                                    u64 offset, u64 val) {
+void EhFrameSection<E>::apply_eh_reloc(Context<E> &ctx, const ElfRel<E> &rel,
+                                       u64 offset, u64 val) {
   u8 *loc = ctx.buf + this->shdr.sh_offset + offset;
 
   switch (rel.r_type) {
@@ -142,12 +192,9 @@ template <>
 void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
   std::span<const ElfRel<E>> rels = get_rels(ctx);
 
-  ElfRel<E> *dynrel = nullptr;
-  if (ctx.reldyn)
-    dynrel = (ElfRel<E> *)(ctx.buf + ctx.reldyn->shdr.sh_offset +
-                           file.reldyn_offset + this->reldyn_offset);
-
-  for (i64 i = 0; i < rels.size(); i++) {
+  // We iterate over relocations in reverse order so that it is easy
+  // to swap instructions for R_SPARC_TLS_GD_CALL.
+  for (i64 i = (i64)rels.size() - 1; i >= 0; i--) {
     const ElfRel<E> &rel = rels[i];
     if (rel.r_type == R_NONE)
       continue;
@@ -155,23 +202,21 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
     Symbol<E> &sym = *file.symbols[rel.r_sym];
     u8 *loc = base + rel.r_offset;
 
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
     u64 S = sym.get_addr(ctx);
     u64 A = rel.r_addend;
-    u64 P = (get_addr() + rel.r_offset);
-    u64 G = (sym.get_got_idx(ctx) * sizeof(Word<E>));
+    u64 P = get_addr() + rel.r_offset;
+    u64 G = sym.get_got_idx(ctx) * sizeof(Word<E>);
     u64 GOT = ctx.got->shdr.sh_addr;
 
+    auto check = [&](i64 val, i64 lo, i64 hi) {
+      check_range(ctx, i, val, lo, hi);
+    };
+
+    auto rs1 = [&] { return *(ub32 *)loc & (0b11111 << 14); };
+    auto rs2 = [&] { return *(ub32 *)loc & 0b11111; };
+    auto rd  = [&] { return *(ub32 *)loc & (0b11111 << 25); };
+
     switch (rel.r_type) {
-    case R_SPARC_64:
-      apply_dyn_absrel(ctx, sym, rel, loc, S, A, P, dynrel);
-      break;
     case R_SPARC_5:
       check(S + A, 0, 1 << 5);
       *(ub32 *)loc |= bits(S + A, 4, 0);
@@ -186,7 +231,7 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
       break;
     case R_SPARC_8:
       check(S + A, 0, 1 << 8);
-      *(u8 *)loc = S + A;
+      *loc = S + A;
       break;
     case R_SPARC_10:
       check(S + A, 0, 1 << 10);
@@ -220,13 +265,12 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
       *(ub32 *)loc = S + A;
       break;
     case R_SPARC_PLT64:
-    case R_SPARC_UA64:
     case R_SPARC_REGISTER:
       *(ub64 *)loc = S + A;
       break;
     case R_SPARC_DISP8:
       check(S + A - P, -(1 << 7), 1 << 7);
-      *(u8 *)loc = S + A - P;
+      *loc = S + A - P;
       break;
     case R_SPARC_DISP16:
       check(S + A - P, -(1 << 15), 1 << 15);
@@ -288,39 +332,34 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
       // We always have to relax a GOT load to a load immediate if a
       // symbol is local, because R_SPARC_GOTDATA_OP cannot represent
       // an addend for a local symbol.
-      if (sym.is_imported || sym.is_ifunc()) {
-        *(ub32 *)loc |= bits(G, 31, 10);
-      } else if (sym.is_absolute()) {
-        i64 val = S + A;
-        *(ub32 *)loc |= bits(val < 0 ? ~val : val, 31, 10);
-      } else {
-        i64 val = S + A - GOT;
-        *(ub32 *)loc |= bits(val < 0 ? ~val : val, 31, 10);
-      }
-      break;
-    case R_SPARC_GOTDATA_OP_LOX10: {
-      if (sym.is_imported || sym.is_ifunc()) {
-        *(ub32 *)loc |= bits(G, 9, 0);
-      } else if (sym.is_absolute()) {
-        i64 val = S + A;
-        *(ub32 *)loc |= bits(val, 9, 0) | (val < 0 ? 0b1'1100'0000'0000 : 0);
-      } else {
-        i64 val = S + A - GOT;
-        *(ub32 *)loc |= bits(val, 9, 0) | (val < 0 ? 0b1'1100'0000'0000 : 0);
-      }
-      break;
-    }
-    case R_SPARC_GOTDATA_OP:
-      if (sym.is_imported || sym.is_ifunc())
-        break;
-
       if (sym.is_absolute()) {
-        // ldx [ %g2 + %g1 ], %g1  →  nop
-        *(ub32 *)loc = 0x0100'0000;
+        i64 val = S + A;
+        *(ub32 *)loc |= bits(val < 0 ? ~val : val, 31, 10);
+      } else if (sym.is_pcrel_linktime_const(ctx)) {
+        i64 val = S + A - GOT;
+        *(ub32 *)loc |= bits(val < 0 ? ~val : val, 31, 10);
       } else {
-        // ldx [ %g2 + %g1 ], %g1  →  add %g2, %g1, %g1
-        *(ub32 *)loc &= 0b00'11111'000000'11111'1'11111111'11111;
-        *(ub32 *)loc |= 0b10'00000'000000'00000'0'00000000'00000;
+        *(ub32 *)loc |= bits(G, 31, 10);
+      }
+      break;
+    case R_SPARC_GOTDATA_OP_LOX10:
+      if (sym.is_absolute()) {
+        i64 val = S + A;
+        *(ub32 *)loc |= bits(val, 9, 0) | (val < 0 ? 0b1'1100'0000'0000 : 0);
+      } else if (sym.is_pcrel_linktime_const(ctx)) {
+        i64 val = S + A - GOT;
+        *(ub32 *)loc |= bits(val, 9, 0) | (val < 0 ? 0b1'1100'0000'0000 : 0);
+      } else {
+        *(ub32 *)loc |= bits(G, 9, 0);
+      }
+      break;
+    case R_SPARC_GOTDATA_OP:
+      if (sym.is_absolute()) {
+        // ldx [ %rs1 + %rs2 ], %rd  →  mov %rs2, %rd
+        *(ub32 *)loc = 0x8010'0000 | rs2() | rd();
+      } else if (sym.is_pcrel_linktime_const(ctx)) {
+        // ldx [ %rs1 + %rs2 ], %rd  →  add %rs1, %rs2, %rd
+        *(ub32 *)loc = 0x8000'0000 | rs1() | rs2() | rd();
       }
       break;
     case R_SPARC_PC10:
@@ -363,27 +402,79 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
       *(ub32 *)loc |= bits(S + A, 11, 0);
       break;
     case R_SPARC_TLS_GD_HI22:
-      *(ub32 *)loc |= bits(sym.get_tlsgd_addr(ctx) + A - GOT, 31, 10);
+      if (sym.has_tlsgd(ctx)) {
+        *(ub32 *)loc |= bits(sym.get_tlsgd_addr(ctx) + A - GOT, 31, 10);
+      } else if (sym.has_gottp(ctx)) {
+        *(ub32 *)loc |= bits(sym.get_gottp_addr(ctx) + A - GOT, 31, 10);
+      } else {
+        *(ub32 *)loc |= bits(~(S + A - ctx.tp_addr), 31, 10);
+      }
       break;
     case R_SPARC_TLS_GD_LO10:
-      *(ub32 *)loc |= bits(sym.get_tlsgd_addr(ctx) + A - GOT, 9, 0);
+      if (sym.has_tlsgd(ctx)) {
+        *(ub32 *)loc |= bits(sym.get_tlsgd_addr(ctx) + A - GOT, 9, 0);
+      } else if (sym.has_gottp(ctx)) {
+        // add %rs1, %rs2, %rd → or  %rs1, $imm, %rd
+        *(ub32 *)loc = 0x8010'2000 | rs1() | rd();
+        *(ub32 *)loc |= bits(sym.get_gottp_addr(ctx) + A - GOT, 9, 0);
+      } else {
+        // add %rs1, %rs2, %rd → xor %rs1, $imm, %rd
+        *(ub32 *)loc = 0x8018'2000 | rs1() | rd();
+        *(ub32 *)loc |= bits(S + A - ctx.tp_addr, 9, 0) | 0b1'1100'0000'0000;
+      }
+      break;
+    case R_SPARC_TLS_GD_ADD:
+      if (sym.has_tlsgd(ctx)) {
+        // do nothing
+      } else if (sym.has_gottp(ctx)) {
+        // add %rs1, %rs2, %rd → ldx [ %rs1 + %rs2 ], %rd
+        *(ub32 *)loc = 0xc058'0000 | rs1() | rs2() | rd();
+      } else {
+        // add %rs1, %rs2, %rd → add %g7, %rs2, %rd
+        *(ub32 *)loc = 0x8001'c000 | rs2() | rd();
+      }
       break;
     case R_SPARC_TLS_GD_CALL:
-    case R_SPARC_TLS_LDM_CALL: {
-      u64 addr;
-      if (ctx.arg.is_static)
-        addr = ctx.extra.tls_get_addr_sec->shdr.sh_addr;
-      else
-        addr = ctx.extra.tls_get_addr_sym->get_addr(ctx);
-
-      *(ub32 *)loc |= bits(addr + A - P, 31, 2);
+      if (sym.has_tlsgd(ctx)) {
+        u64 addr = ctx.extra.tls_get_addr->get_addr(ctx);
+        *(ub32 *)loc |= bits(addr + A - P, 31, 2);
+      } else if (sym.has_gottp(ctx)) {
+        // When we rewrite a branch instruction with a non-branch one,
+        // we need to swap the instruction and the following one so that
+        // the original execution order, which is inverted due to the
+        // branch delay slot, is preserved.
+        //
+        // Since we apply relocations from the end to the beginning,
+        // the instruction at loc + 4 is already complete.
+        memcpy(loc, loc + 4, 4);
+        *(ub32 *)(loc + 4) = 0x9001'c008; // add %g7, %o0, %o0
+      } else {
+        *(ub32 *)loc = 0x0100'0000; // call → nop
+      }
       break;
-    }
     case R_SPARC_TLS_LDM_HI22:
-      *(ub32 *)loc |= bits(ctx.got->get_tlsld_addr(ctx) + A - GOT, 31, 10);
+      if (ctx.got->has_tlsld(ctx))
+        *(ub32 *)loc |= bits(ctx.got->get_tlsld_addr(ctx) + A - GOT, 31, 10);
+      else
+        *(ub32 *)loc |= bits(ctx.tp_addr - ctx.tls_begin, 31, 10);
       break;
     case R_SPARC_TLS_LDM_LO10:
-      *(ub32 *)loc |= bits(ctx.got->get_tlsld_addr(ctx) + A - GOT, 9, 0);
+      if (ctx.got->has_tlsld(ctx))
+        *(ub32 *)loc |= bits(ctx.got->get_tlsld_addr(ctx) + A - GOT, 9, 0);
+      else
+        *(ub32 *)loc |= bits(ctx.tp_addr - ctx.tls_begin, 9, 0);
+      break;
+    case R_SPARC_TLS_LDM_ADD:
+      if (!ctx.got->has_tlsld(ctx))
+        *(ub32 *)loc = 0x8021'c000 | rs2() | rd(); // sub %g7, %rs2, %rd
+      break;
+    case R_SPARC_TLS_LDM_CALL:
+      if (ctx.got->has_tlsld(ctx)) {
+        u64 addr = ctx.extra.tls_get_addr->get_addr(ctx);
+        *(ub32 *)loc |= bits(addr + A - P, 31, 2);
+      } else {
+        *(ub32 *)loc = 0x0100'0000; // nop
+      }
       break;
     case R_SPARC_TLS_LDO_HIX22:
       *(ub32 *)loc |= bits(S + A - ctx.dtp_addr, 31, 10);
@@ -406,8 +497,8 @@ void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
     case R_SPARC_SIZE32:
       *(ub32 *)loc = sym.esym().st_size + A;
       break;
-    case R_SPARC_TLS_GD_ADD:
-    case R_SPARC_TLS_LDM_ADD:
+    case R_SPARC_64:
+    case R_SPARC_UA64:
     case R_SPARC_TLS_LDO_ADD:
     case R_SPARC_TLS_IE_LD:
     case R_SPARC_TLS_IE_LDX:
@@ -425,25 +516,12 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
     u8 *loc = base + rel.r_offset;
 
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
-
-    auto check = [&](i64 val, i64 lo, i64 hi) {
-      if (val < lo || hi <= val)
-        Error(ctx) << *this << ": relocation " << rel << " against "
-                   << sym << " out of range: " << val << " is not in ["
-                   << lo << ", " << hi << ")";
-    };
-
     SectionFragment<E> *frag;
     i64 frag_addend;
     std::tie(frag, frag_addend) = get_fragment(ctx, rel);
@@ -451,6 +529,10 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
     u64 S = frag ? frag->get_addr(ctx) : sym.get_addr(ctx);
     u64 A = frag ? frag_addend : (i64)rel.r_addend;
 
+    auto check = [&](i64 val, i64 lo, i64 hi) {
+      check_range(ctx, val, i, lo, hi);
+    };
+
     switch (rel.r_type) {
     case R_SPARC_64:
     case R_SPARC_UA64:
@@ -460,12 +542,10 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
         *(ub64 *)loc = S + A;
       break;
     case R_SPARC_32:
-    case R_SPARC_UA32: {
-      i64 val = S + A;
-      check(val, 0, 1LL << 32);
-      *(ub32 *)loc = val;
+    case R_SPARC_UA32:
+      check(S + A, 0, 1LL << 32);
+      *(ub32 *)loc = S + A;
       break;
-    }
     case R_SPARC_TLS_DTPOFF32:
       *(ub32 *)loc = S + A - ctx.dtp_addr;
       break;
@@ -481,31 +561,21 @@ void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
 template <>
 void InputSection<E>::scan_relocations(Context<E> &ctx) {
   assert(shdr().sh_flags & SHF_ALLOC);
-
-  this->reldyn_offset = file.num_dynrel * sizeof(ElfRel<E>);
   std::span<const ElfRel<E>> rels = get_rels(ctx);
+  bool needs_tlsgd = false;
 
   // Scan relocations
   for (i64 i = 0; i < rels.size(); i++) {
     const ElfRel<E> &rel = rels[i];
-    if (rel.r_type == R_NONE)
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
       continue;
 
     Symbol<E> &sym = *file.symbols[rel.r_sym];
-    const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
-
-    if (!is_resolved(sym, esym)) {
-      record_undef_error(ctx, rel);
-      continue;
-    }
 
     if (sym.is_ifunc())
       sym.flags |= NEEDS_GOT | NEEDS_PLT;
 
     switch (rel.r_type) {
-    case R_SPARC_64:
-      scan_dyn_absrel(ctx, sym, rel);
-      break;
     case R_SPARC_8:
     case R_SPARC_5:
     case R_SPARC_6:
@@ -519,7 +589,6 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
     case R_SPARC_REGISTER:
     case R_SPARC_UA16:
     case R_SPARC_UA32:
-    case R_SPARC_UA64:
     case R_SPARC_PC_HM10:
     case R_SPARC_OLO10:
     case R_SPARC_LOX10:
@@ -570,30 +639,42 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
       scan_pcrel(ctx, sym, rel);
       break;
     case R_SPARC_TLS_GD_HI22:
-      sym.flags |= NEEDS_TLSGD;
+      if (ctx.arg.static_ || (ctx.arg.relax && sym.is_tprel_linktime_const(ctx))) {
+        // We always relax if -static because libc.a doesn't contain
+        // __tls_get_addr().
+      } else if (ctx.arg.relax && sym.is_tprel_runtime_const(ctx)) {
+        sym.flags |= NEEDS_GOTTP;
+      } else {
+        sym.flags |= NEEDS_TLSGD;
+        needs_tlsgd = true;
+      }
       break;
     case R_SPARC_TLS_LDM_HI22:
-      ctx.needs_tlsld = true;
+      if (ctx.arg.static_ || (ctx.arg.relax && !ctx.arg.shared)) {
+        // We always relax if -static because libc.a doesn't contain
+        // __tls_get_addr().
+      } else {
+        ctx.needs_tlsld = true;
+      }
       break;
     case R_SPARC_TLS_IE_HI22:
       sym.flags |= NEEDS_GOTTP;
       break;
-    case R_SPARC_TLS_GD_CALL:
-    case R_SPARC_TLS_LDM_CALL:
-      if (!ctx.arg.is_static && ctx.extra.tls_get_addr_sym->is_imported)
-        ctx.extra.tls_get_addr_sym->flags |= NEEDS_PLT;
-      break;
     case R_SPARC_TLS_LE_HIX22:
     case R_SPARC_TLS_LE_LOX10:
       check_tlsle(ctx, sym, rel);
       break;
+    case R_SPARC_64:
+    case R_SPARC_UA64:
     case R_SPARC_GOTDATA_OP_LOX10:
     case R_SPARC_GOTDATA_OP:
     case R_SPARC_GOTDATA_LOX10:
     case R_SPARC_TLS_GD_LO10:
     case R_SPARC_TLS_GD_ADD:
+    case R_SPARC_TLS_GD_CALL:
     case R_SPARC_TLS_LDM_LO10:
     case R_SPARC_TLS_LDM_ADD:
+    case R_SPARC_TLS_LDM_CALL:
     case R_SPARC_TLS_LDO_HIX22:
     case R_SPARC_TLS_LDO_LOX10:
     case R_SPARC_TLS_LDO_ADD:
@@ -604,30 +685,17 @@ void InputSection<E>::scan_relocations(Context<E> &ctx) {
     case R_SPARC_SIZE32:
       break;
     default:
-      Fatal(ctx) << *this << ": scan_relocations: " << rel;
+      Error(ctx) << *this << ": unknown relocation: " << rel;
     }
   }
+
+  // TLS_GD_CALL and TLS_LDM_CALL relocations implicitly refer to
+  // __tls_get_addr, which may be dynamically linked from libc.so.
+  Symbol<E> &sym = *ctx.extra.tls_get_addr;
+  if (sym.is_imported && (needs_tlsgd || ctx.needs_tlsld))
+    sym.flags |= NEEDS_PLT;
 }
 
-// __tls_get_addr is not defined by libc.a, so we can't use that function
-// in statically-linked executables. This section provides a replacement.
-void SparcTlsGetAddrSection::copy_buf(Context<E> &ctx) {
-  ub32 *buf = (ub32 *)(ctx.buf + this->shdr.sh_offset);
+} // namespace mold
 
-  static const ub32 insn[] = {
-    0x0300'0000, // sethi  %hi(TP_SIZE), %g1
-    0x8210'6000, // or   %g1, %lo(TP_SIZE), %g1
-    0x8221'c001, // sub  %g7, %g1, %g1
-    0xd05a'2008, // ldx  [ %o0 + 8 ], %o0
-    0x81c3'e008, // retl
-    0x9000'4008, // add  %g1, %o0, %o0
-  };
-
-  assert(this->shdr.sh_size == sizeof(insn));
-  memcpy(buf, insn, sizeof(insn));
-
-  buf[0] |= bits(ctx.tp_addr - ctx.tls_begin, 31, 10);
-  buf[1] |= bits(ctx.tp_addr - ctx.tls_begin, 9, 0);
-}
-
-} // namespace mold::elf
+#endif

src/arch-x86-64.cc

@@ -0,0 +1,955 @@
+// Supporting x86-64 is straightforward. Unlike its predecessor, i386,
+// x86-64 supports PC-relative addressing for position-independent code.
+// Being CISC, its instructions are variable in size. Branch instructions
+// take 4 bytes offsets, so we don't need range extension thunks.
+//
+// The psABI specifies %r11 as neither caller- nor callee-saved. It's
+// intentionally left out so that we can use it as a scratch register in
+// PLT.
+//
+// Thread Pointer (TP) is stored not to a general-purpose register but to
+// FS segment register. Segment register is a 64-bits register which can
+// be used as a base address for memory access. Each thread has a unique
+// FS value, and they access their thread-local variables relative to FS
+// as %fs:offset_from_tp.
+//
+// The value of a segment register itself is not generally readable from
+// the user space. As a workaround, libc initializes %fs:0 (the first word
+// referenced by FS) to the value of %fs itself. So we can obtain TP just
+// by `mov %fs:0, %rax` if we need it.
+//
+// For historical reasons, TP points past the end of the TLS block on x86.
+// This is contrary to other psABIs which usually use the beginning of the
+// TLS block as TP (with some addend). As a result, offsets from TP to
+// thread-local variables (TLVs) in the main executable are all negative.
+//
+// https://gitlab.com/x86-psABIs/x86-64-ABI
+
+#if MOLD_X86_64
+
+#include "mold.h"
+#include <tbb/parallel_for_each.h>
+
+namespace mold {
+
+using E = X86_64;
+
+// This is a security-enhanced version of the regular PLT. The PLT
+// header and each PLT entry starts with endbr64 for the Intel's
+// control-flow enforcement security mechanism.
+//
+// Note that our IBT-enabled PLT instruction sequence is different
+// from the one used in GNU ld. GNU's IBTPLT implementation uses two
+// separate sections (.plt and .plt.sec) in which one PLT entry takes
+// 32 bytes in total. Our IBTPLT consists of just .plt and each entry
+// is 16 bytes long.
+//
+// Our PLT entry clobbers %r11, but that's fine because the resolver
+// function (_dl_runtime_resolve) clobbers %r11 anyway.
+template <>
+void write_plt_header(Context<E> &ctx, u8 *buf) {
+  static const u8 insn[] = {
+    0xf3, 0x0f, 0x1e, 0xfa, // endbr64
+    0x41, 0x53,             // push %r11
+    0xff, 0x35, 0, 0, 0, 0, // push GOTPLT+8(%rip)
+    0xff, 0x25, 0, 0, 0, 0, // jmp *GOTPLT+16(%rip)
+    0xcc, 0xcc, 0xcc, 0xcc, // (padding)
+    0xcc, 0xcc, 0xcc, 0xcc, // (padding)
+    0xcc, 0xcc, 0xcc, 0xcc, // (padding)
+    0xcc, 0xcc,             // (padding)
+  };
+
+  memcpy(buf, insn, sizeof(insn));
+  *(ul32 *)(buf + 8) = ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 4;
+  *(ul32 *)(buf + 14) = ctx.gotplt->shdr.sh_addr - ctx.plt->shdr.sh_addr - 2;
+}
+
+template <>
+void write_plt_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
+  // Only a canonical PLT can be address-taken; there's no way to take
+  // an address of a non-canonical PLT. Therefore, a non-canonical PLT
+  // doesn't have to start with an endbr64.
+  if (sym.is_canonical) {
+    static const u8 insn[] = {
+      0xf3, 0x0f, 0x1e, 0xfa, // endbr64
+      0x41, 0xbb, 0, 0, 0, 0, // mov $index_in_relplt, %r11d
+      0xff, 0x25, 0, 0, 0, 0, // jmp *foo@GOTPLT
+    };
+
+    memcpy(buf, insn, sizeof(insn));
+    *(ul32 *)(buf + 6) = sym.get_plt_idx(ctx);
+    *(ul32 *)(buf + 12) = sym.get_gotplt_addr(ctx) - sym.get_plt_addr(ctx) - 16;
+  } else {
+    static const u8 insn[] = {
+      0x41, 0xbb, 0, 0, 0, 0, // mov $index_in_relplt, %r11d
+      0xff, 0x25, 0, 0, 0, 0, // jmp *foo@GOTPLT
+      0xcc, 0xcc, 0xcc, 0xcc, // (padding)
+    };
+
+    memcpy(buf, insn, sizeof(insn));
+    *(ul32 *)(buf + 2) = sym.get_plt_idx(ctx);
+    *(ul32 *)(buf + 8) = sym.get_gotplt_addr(ctx) - sym.get_plt_addr(ctx) - 12;
+  }
+}
+
+template <>
+void write_pltgot_entry(Context<E> &ctx, u8 *buf, Symbol<E> &sym) {
+  static const u8 insn[] = {
+    0xff, 0x25, 0, 0, 0, 0, // jmp *foo@GOT
+    0xcc, 0xcc,             // (padding)
+  };
+
+  memcpy(buf, insn, sizeof(insn));
+  *(ul32 *)(buf + 2) = sym.get_got_pltgot_addr(ctx) - sym.get_plt_addr(ctx) - 6;
+}
+
+template <>
+void EhFrameSection<E>::apply_eh_reloc(Context<E> &ctx, const ElfRel<E> &rel,
+                                       u64 offset, u64 val) {
+  u8 *loc = ctx.buf + this->shdr.sh_offset + offset;
+
+  switch (rel.r_type) {
+  case R_NONE:
+    break;
+  case R_X86_64_32:
+    *(ul32 *)loc = val;
+    break;
+  case R_X86_64_64:
+    *(ul64 *)loc = val;
+    break;
+  case R_X86_64_PC32:
+    *(ul32 *)loc = val - this->shdr.sh_addr - offset;
+    break;
+  case R_X86_64_PC64:
+    *(ul64 *)loc = val - this->shdr.sh_addr - offset;
+    break;
+  default:
+    Fatal(ctx) << "unsupported relocation in .eh_frame: " << rel;
+  }
+}
+
+static u32 relax_gotpcrelx(u8 *loc, const ElfRel<E> &rel) {
+  if (rel.r_type == R_X86_64_GOTPCRELX) {
+    switch ((loc[-2] << 8) | loc[-1]) {
+    case 0xff15: return 0x40e8; // call *0(%rip) -> call 0
+    case 0xff25: return 0x40e9; // jmp  *0(%rip) -> jmp  0
+    }
+  } else {
+    assert(rel.r_type == R_X86_64_REX_GOTPCRELX ||
+           rel.r_type == R_X86_64_CODE_4_GOTPCRELX);
+    switch ((loc[-3] << 16) | (loc[-2] << 8) | loc[-1]) {
+    case 0x488b05: return 0x8d05; // mov 0(%rip), %rax -> lea 0(%rip), %rax
+    case 0x488b0d: return 0x8d0d; // mov 0(%rip), %rcx -> lea 0(%rip), %rcx
+    case 0x488b15: return 0x8d15; // mov 0(%rip), %rdx -> lea 0(%rip), %rdx
+    case 0x488b1d: return 0x8d1d; // mov 0(%rip), %rbx -> lea 0(%rip), %rbx
+    case 0x488b25: return 0x8d25; // mov 0(%rip), %rsp -> lea 0(%rip), %rsp
+    case 0x488b2d: return 0x8d2d; // mov 0(%rip), %rbp -> lea 0(%rip), %rbp
+    case 0x488b35: return 0x8d35; // mov 0(%rip), %rsi -> lea 0(%rip), %rsi
+    case 0x488b3d: return 0x8d3d; // mov 0(%rip), %rdi -> lea 0(%rip), %rdi
+    case 0x4c8b05: return 0x8d05; // mov 0(%rip), %r8  -> lea 0(%rip), %r8
+    case 0x4c8b0d: return 0x8d0d; // mov 0(%rip), %r9  -> lea 0(%rip), %r9
+    case 0x4c8b15: return 0x8d15; // mov 0(%rip), %r10 -> lea 0(%rip), %r10
+    case 0x4c8b1d: return 0x8d1d; // mov 0(%rip), %r11 -> lea 0(%rip), %r11
+    case 0x4c8b25: return 0x8d25; // mov 0(%rip), %r12 -> lea 0(%rip), %r12
+    case 0x4c8b2d: return 0x8d2d; // mov 0(%rip), %r13 -> lea 0(%rip), %r13
+    case 0x4c8b35: return 0x8d35; // mov 0(%rip), %r14 -> lea 0(%rip), %r14
+    case 0x4c8b3d: return 0x8d3d; // mov 0(%rip), %r15 -> lea 0(%rip), %r15
+    }
+  }
+  return 0;
+}
+
+static u32 relax_gottpoff(u8 *loc, const ElfRel<E> &rel) {
+  if (rel.r_type == R_X86_64_GOTTPOFF) {
+    switch ((loc[-3] << 16) | (loc[-2] << 8) | loc[-1]) {
+    case 0x488b05: return 0x48c7c0; // mov 0(%rip), %rax -> mov $0, %rax
+    case 0x488b0d: return 0x48c7c1; // mov 0(%rip), %rcx -> mov $0, %rcx
+    case 0x488b15: return 0x48c7c2; // mov 0(%rip), %rdx -> mov $0, %rdx
+    case 0x488b1d: return 0x48c7c3; // mov 0(%rip), %rbx -> mov $0, %rbx
+    case 0x488b25: return 0x48c7c4; // mov 0(%rip), %rsp -> mov $0, %rsp
+    case 0x488b2d: return 0x48c7c5; // mov 0(%rip), %rbp -> mov $0, %rbp
+    case 0x488b35: return 0x48c7c6; // mov 0(%rip), %rsi -> mov $0, %rsi
+    case 0x488b3d: return 0x48c7c7; // mov 0(%rip), %rdi -> mov $0, %rdi
+    case 0x4c8b05: return 0x49c7c0; // mov 0(%rip), %r8  -> mov $0, %r8
+    case 0x4c8b0d: return 0x49c7c1; // mov 0(%rip), %r9  -> mov $0, %r9
+    case 0x4c8b15: return 0x49c7c2; // mov 0(%rip), %r10 -> mov $0, %r10
+    case 0x4c8b1d: return 0x49c7c3; // mov 0(%rip), %r11 -> mov $0, %r11
+    case 0x4c8b25: return 0x49c7c4; // mov 0(%rip), %r12 -> mov $0, %r12
+    case 0x4c8b2d: return 0x49c7c5; // mov 0(%rip), %r13 -> mov $0, %r13
+    case 0x4c8b35: return 0x49c7c6; // mov 0(%rip), %r14 -> mov $0, %r14
+    case 0x4c8b3d: return 0x49c7c7; // mov 0(%rip), %r15 -> mov $0, %r15
+    }
+  } else {
+    assert(rel.r_type == R_X86_64_CODE_4_GOTTPOFF);
+    switch ((loc[-3] << 16) | (loc[-2] << 8) | loc[-1]) {
+    case 0x488b05: return 0x18c7c0; // mov 0(%rip), %r16 -> mov $0, %r16
+    case 0x488b0d: return 0x18c7c1; // mov 0(%rip), %r17 -> mov $0, %r17
+    case 0x488b15: return 0x18c7c2; // mov 0(%rip), %r18 -> mov $0, %r18
+    case 0x488b1d: return 0x18c7c3; // mov 0(%rip), %r19 -> mov $0, %r19
+    case 0x488b25: return 0x18c7c4; // mov 0(%rip), %r20 -> mov $0, %r20
+    case 0x488b2d: return 0x18c7c5; // mov 0(%rip), %r21 -> mov $0, %r21
+    case 0x488b35: return 0x18c7c6; // mov 0(%rip), %r22 -> mov $0, %r22
+    case 0x488b3d: return 0x18c7c7; // mov 0(%rip), %r23 -> mov $0, %r23
+    case 0x4c8b05: return 0x19c7c0; // mov 0(%rip), %r24 -> mov $0, %r24
+    case 0x4c8b0d: return 0x19c7c1; // mov 0(%rip), %r25 -> mov $0, %r25
+    case 0x4c8b15: return 0x19c7c2; // mov 0(%rip), %r26 -> mov $0, %r26
+    case 0x4c8b1d: return 0x19c7c3; // mov 0(%rip), %r27 -> mov $0, %r27
+    case 0x4c8b25: return 0x19c7c4; // mov 0(%rip), %r28 -> mov $0, %r28
+    case 0x4c8b2d: return 0x19c7c5; // mov 0(%rip), %r29 -> mov $0, %r29
+    case 0x4c8b35: return 0x19c7c6; // mov 0(%rip), %r30 -> mov $0, %r30
+    case 0x4c8b3d: return 0x19c7c7; // mov 0(%rip), %r31 -> mov $0, %r31
+    }
+  }
+  return 0;
+}
+
+static u32 relax_tlsdesc_to_ie(u8 *loc, const ElfRel<E> &rel) {
+  if (rel.r_type == R_X86_64_GOTPC32_TLSDESC) {
+    switch ((loc[-3] << 16) | (loc[-2] << 8) | loc[-1]) {
+    case 0x488d05: return 0x488b05; // lea 0(%rip), %rax -> mov 0(%rip), %rax
+    case 0x488d0d: return 0x488b0d; // lea 0(%rip), %rcx -> mov 0(%rip), %rcx
+    case 0x488d15: return 0x488b15; // lea 0(%rip), %rdx -> mov 0(%rip), %rdx
+    case 0x488d1d: return 0x488b1d; // lea 0(%rip), %rbx -> mov 0(%rip), %rbx
+    case 0x488d25: return 0x488b25; // lea 0(%rip), %rsp -> mov 0(%rip), %rsp
+    case 0x488d2d: return 0x488b2d; // lea 0(%rip), %rbp -> mov 0(%rip), %rbp
+    case 0x488d35: return 0x488b35; // lea 0(%rip), %rsi -> mov 0(%rip), %rsi
+    case 0x488d3d: return 0x488b3d; // lea 0(%rip), %rdi -> mov 0(%rip), %rdi
+    case 0x4c8d05: return 0x4c8b05; // lea 0(%rip), %r8  -> mov 0(%rip), %r8
+    case 0x4c8d0d: return 0x4c8b0d; // lea 0(%rip), %r9  -> mov 0(%rip), %r9
+    case 0x4c8d15: return 0x4c8b15; // lea 0(%rip), %r10 -> mov 0(%rip), %r10
+    case 0x4c8d1d: return 0x4c8b1d; // lea 0(%rip), %r11 -> mov 0(%rip), %r11
+    case 0x4c8d25: return 0x4c8b25; // lea 0(%rip), %r12 -> mov 0(%rip), %r12
+    case 0x4c8d2d: return 0x4c8b2d; // lea 0(%rip), %r13 -> mov 0(%rip), %r13
+    case 0x4c8d35: return 0x4c8b35; // lea 0(%rip), %r14 -> mov 0(%rip), %r14
+    case 0x4c8d3d: return 0x4c8b3d; // lea 0(%rip), %r15 -> mov 0(%rip), %r15
+    }
+  } else {
+    assert(rel.r_type == R_X86_64_CODE_4_GOTPC32_TLSDESC);
+    switch ((loc[-3] << 16) | (loc[-2] << 8) | loc[-1]) {
+    case 0x488d05: return 0x488b05; // lea 0(%rip), %r16 -> mov 0(%rip), %r16
+    case 0x488d0d: return 0x488b0d; // lea 0(%rip), %r17 -> mov 0(%rip), %r17
+    case 0x488d15: return 0x488b15; // lea 0(%rip), %r18 -> mov 0(%rip), %r18
+    case 0x488d1d: return 0x488b1d; // lea 0(%rip), %r19 -> mov 0(%rip), %r19
+    case 0x488d25: return 0x488b25; // lea 0(%rip), %r20 -> mov 0(%rip), %r20
+    case 0x488d2d: return 0x488b2d; // lea 0(%rip), %r21 -> mov 0(%rip), %r21
+    case 0x488d35: return 0x488b35; // lea 0(%rip), %r22 -> mov 0(%rip), %r22
+    case 0x488d3d: return 0x488b3d; // lea 0(%rip), %r23 -> mov 0(%rip), %r23
+    case 0x4c8d05: return 0x4c8b05; // lea 0(%rip), %r24 -> mov 0(%rip), %r24
+    case 0x4c8d0d: return 0x4c8b0d; // lea 0(%rip), %r25 -> mov 0(%rip), %r25
+    case 0x4c8d15: return 0x4c8b15; // lea 0(%rip), %r26 -> mov 0(%rip), %r26
+    case 0x4c8d1d: return 0x4c8b1d; // lea 0(%rip), %r27 -> mov 0(%rip), %r27
+    case 0x4c8d25: return 0x4c8b25; // lea 0(%rip), %r28 -> mov 0(%rip), %r28
+    case 0x4c8d2d: return 0x4c8b2d; // lea 0(%rip), %r29 -> mov 0(%rip), %r29
+    case 0x4c8d35: return 0x4c8b35; // lea 0(%rip), %r30 -> mov 0(%rip), %r30
+    case 0x4c8d3d: return 0x4c8b3d; // lea 0(%rip), %r31 -> mov 0(%rip), %r31
+    }
+  }
+  return 0;
+}
+
+static u32 relax_tlsdesc_to_le(u8 *loc, const ElfRel<E> &rel) {
+  if (rel.r_type == R_X86_64_GOTPC32_TLSDESC) {
+    switch ((loc[-3] << 16) | (loc[-2] << 8) | loc[-1]) {
+    case 0x488d05: return 0x48c7c0; // lea 0(%rip), %rax -> mov $0, %rax
+    case 0x488d0d: return 0x48c7c1; // lea 0(%rip), %rcx -> mov $0, %rcx
+    case 0x488d15: return 0x48c7c2; // lea 0(%rip), %rdx -> mov $0, %rdx
+    case 0x488d1d: return 0x48c7c3; // lea 0(%rip), %rbx -> mov $0, %rbx
+    case 0x488d25: return 0x48c7c4; // lea 0(%rip), %rsp -> mov $0, %rsp
+    case 0x488d2d: return 0x48c7c5; // lea 0(%rip), %rbp -> mov $0, %rbp
+    case 0x488d35: return 0x48c7c6; // lea 0(%rip), %rsi -> mov $0, %rsi
+    case 0x488d3d: return 0x48c7c7; // lea 0(%rip), %rdi -> mov $0, %rdi
+    case 0x4c8d05: return 0x49c7c0; // lea 0(%rip), %r8  -> mov $0, %r8
+    case 0x4c8d0d: return 0x49c7c1; // lea 0(%rip), %r9  -> mov $0, %r9
+    case 0x4c8d15: return 0x49c7c2; // lea 0(%rip), %r10 -> mov $0, %r10
+    case 0x4c8d1d: return 0x49c7c3; // lea 0(%rip), %r11 -> mov $0, %r11
+    case 0x4c8d25: return 0x49c7c4; // lea 0(%rip), %r12 -> mov $0, %r12
+    case 0x4c8d2d: return 0x49c7c5; // lea 0(%rip), %r13 -> mov $0, %r13
+    case 0x4c8d35: return 0x49c7c6; // lea 0(%rip), %r14 -> mov $0, %r14
+    case 0x4c8d3d: return 0x49c7c7; // lea 0(%rip), %r15 -> mov $0, %r15
+    }
+  } else {
+    assert(rel.r_type == R_X86_64_CODE_4_GOTPC32_TLSDESC);
+    switch ((loc[-3] << 16) | (loc[-2] << 8) | loc[-1]) {
+    case 0x488d05: return 0x18c7c0; // lea 0(%rip), %r16 -> mov $0, %r16
+    case 0x488d0d: return 0x18c7c1; // lea 0(%rip), %r17 -> mov $0, %r17
+    case 0x488d15: return 0x18c7c2; // lea 0(%rip), %r18 -> mov $0, %r18
+    case 0x488d1d: return 0x18c7c3; // lea 0(%rip), %r19 -> mov $0, %r19
+    case 0x488d25: return 0x18c7c4; // lea 0(%rip), %r20 -> mov $0, %r20
+    case 0x488d2d: return 0x18c7c5; // lea 0(%rip), %r21 -> mov $0, %r21
+    case 0x488d35: return 0x18c7c6; // lea 0(%rip), %r22 -> mov $0, %r22
+    case 0x488d3d: return 0x18c7c7; // lea 0(%rip), %r23 -> mov $0, %r23
+    case 0x4c8d05: return 0x19c7c0; // lea 0(%rip), %r24 -> mov $0, %r24
+    case 0x4c8d0d: return 0x19c7c1; // lea 0(%rip), %r25 -> mov $0, %r25
+    case 0x4c8d15: return 0x19c7c2; // lea 0(%rip), %r26 -> mov $0, %r26
+    case 0x4c8d1d: return 0x19c7c3; // lea 0(%rip), %r27 -> mov $0, %r27
+    case 0x4c8d25: return 0x19c7c4; // lea 0(%rip), %r28 -> mov $0, %r28
+    case 0x4c8d2d: return 0x19c7c5; // lea 0(%rip), %r29 -> mov $0, %r29
+    case 0x4c8d35: return 0x19c7c6; // lea 0(%rip), %r30 -> mov $0, %r30
+    case 0x4c8d3d: return 0x19c7c7; // lea 0(%rip), %r31 -> mov $0, %r31
+    }
+  }
+  return 0;
+}
+
+// Rewrite a function call to __tls_get_addr to a cheaper instruction
+// sequence. We can do this when we know the thread-local variable's TP-
+// relative address at link-time.
+static void relax_gd_to_le(u8 *loc, const ElfRel<E> &rel, u64 val) {
+  switch (rel.r_type) {
+  case R_X86_64_PLT32:
+  case R_X86_64_PC32:
+  case R_X86_64_GOTPCREL:
+  case R_X86_64_GOTPCRELX: {
+    // The original instructions are the following:
+    //
+    //  66 48 8d 3d 00 00 00 00    lea  foo@tlsgd(%rip), %rdi
+    //  66 66 48 e8 00 00 00 00    call __tls_get_addr
+    //
+    // or
+    //
+    //  66 48 8d 3d 00 00 00 00    lea foo@tlsgd(%rip), %rdi
+    //  66 48 ff 15 00 00 00 00    call *__tls_get_addr@GOT(%rip)
+    static const u8 insn[] = {
+      0x64, 0x48, 0x8b, 0x04, 0x25, 0, 0, 0, 0, // mov %fs:0, %rax
+      0x48, 0x81, 0xc0, 0, 0, 0, 0,             // add $tp_offset, %rax
+    };
+    memcpy(loc - 4, insn, sizeof(insn));
+    *(ul32 *)(loc + 8) = val;
+    break;
+  }
+  case R_X86_64_PLTOFF64: {
+    // The original instructions are the following:
+    //
+    //  48 8d 3d 00 00 00 00           lea    foo@tlsgd(%rip), %rdi
+    //  48 b8 00 00 00 00 00 00 00 00  movabs __tls_get_addr, %rax
+    //  48 01 d8                       add    %rbx, %rax
+    //  ff d0                          call   *%rax
+    static const u8 insn[] = {
+      0x64, 0x48, 0x8b, 0x04, 0x25, 0, 0, 0, 0, // mov %fs:0, %rax
+      0x48, 0x81, 0xc0, 0, 0, 0, 0,             // add $tp_offset, %rax
+      0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00,       // nop
+    };
+    memcpy(loc - 3, insn, sizeof(insn));
+    *(ul32 *)(loc + 9) = val;
+    break;
+  }
+  default:
+    unreachable();
+  }
+}
+
+static void relax_gd_to_ie(u8 *loc, const ElfRel<E> &rel, u64 val) {
+  switch (rel.r_type) {
+  case R_X86_64_PLT32:
+  case R_X86_64_PC32:
+  case R_X86_64_GOTPCREL:
+  case R_X86_64_GOTPCRELX: {
+    static const u8 insn[] = {
+      0x64, 0x48, 0x8b, 0x04, 0x25, 0, 0, 0, 0, // mov %fs:0, %rax
+      0x48, 0x03, 0x05, 0, 0, 0, 0,             // add foo@gottpoff(%rip), %rax
+    };
+    memcpy(loc - 4, insn, sizeof(insn));
+    *(ul32 *)(loc + 8) = val - 12;
+    break;
+  }
+  case R_X86_64_PLTOFF64: {
+    static const u8 insn[] = {
+      0x64, 0x48, 0x8b, 0x04, 0x25, 0, 0, 0, 0, // mov %fs:0, %rax
+      0x48, 0x03, 0x05, 0, 0, 0, 0,             // add foo@gottpoff(%rip), %rax
+      0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00,       // nop
+    };
+    memcpy(loc - 3, insn, sizeof(insn));
+    *(ul32 *)(loc + 9) = val - 13;
+    break;
+  }
+  default:
+    unreachable();
+  }
+}
+
+// Rewrite a function call to __tls_get_addr to a cheaper instruction
+// sequence. The difference from relax_gd_to_le is that we are materializing
+// the address of the beginning of TLS block instead of an address of a
+// particular thread-local variable.
+static void relax_ld_to_le(u8 *loc, const ElfRel<E> &rel, i64 tls_size) {
+  switch (rel.r_type) {
+  case R_X86_64_PLT32:
+  case R_X86_64_PC32: {
+    // The original instructions are the following:
+    //
+    //  48 8d 3d 00 00 00 00    lea    foo@tlsld(%rip), %rdi
+    //  e8 00 00 00 00          call   __tls_get_addr
+    //
+    // Because the original instruction sequence is so short that we need a
+    // little bit of code golfing here. "mov %fs:0, %rax" is 9 byte long, so
+    // xor + mov is shorter. Note that `xor %eax, %eax` zero-clears %eax.
+    static const u8 insn[] = {
+      0x31, 0xc0,                   // xor %eax, %eax
+      0x64, 0x48, 0x8b, 0x00,       // mov %fs:(%rax), %rax
+      0x48, 0x2d, 0, 0, 0, 0,       // sub $tls_size, %rax
+    };
+    memcpy(loc - 3, insn, sizeof(insn));
+    *(ul32 *)(loc + 5) = tls_size;
+    break;
+  }
+  case R_X86_64_GOTPCREL:
+  case R_X86_64_GOTPCRELX: {
+    // The original instructions are the following:
+    //
+    //  48 8d 3d 00 00 00 00    lea    foo@tlsld(%rip), %rdi
+    //  ff 15 00 00 00 00       call   *__tls_get_addr@GOT(%rip)
+    static const u8 insn[] = {
+      0x48, 0x31, 0xc0,             // xor %rax, %rax
+      0x64, 0x48, 0x8b, 0x00,       // mov %fs:(%rax), %rax
+      0x48, 0x2d, 0, 0, 0, 0,       // sub $tls_size, %rax
+    };
+    memcpy(loc - 3, insn, sizeof(insn));
+    *(ul32 *)(loc + 6) = tls_size;
+    break;
+  }
+  case R_X86_64_PLTOFF64: {
+    // The original instructions are the following:
+    //
+    //  48 8d 3d 00 00 00 00           lea    foo@tlsld(%rip), %rdi
+    //  48 b8 00 00 00 00 00 00 00 00  movabs __tls_get_addr@GOTOFF, %rax
+    //  48 01 d8                       add    %rbx, %rax
+    //  ff d0                          call   *%rax
+    static const u8 insn[] = {
+      0x64, 0x48, 0x8b, 0x04, 0x25, 0, 0, 0, 0, // mov %fs:0, %rax
+      0x48, 0x2d, 0, 0, 0, 0,                   // sub $tls_size, %rax
+      0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00, // nop
+    };
+    memcpy(loc - 3, insn, sizeof(insn));
+    *(ul32 *)(loc + 8) = tls_size;
+    break;
+  }
+  default:
+    unreachable();
+  }
+}
+
+// Apply relocations to SHF_ALLOC sections (i.e. sections that are
+// mapped to memory at runtime) based on the result of
+// scan_relocations().
+template <>
+void InputSection<E>::apply_reloc_alloc(Context<E> &ctx, u8 *base) {
+  std::span<const ElfRel<E>> rels = get_rels(ctx);
+
+  for (i64 i = 0; i < rels.size(); i++) {
+    const ElfRel<E> &rel = rels[i];
+    if (rel.r_type == R_NONE)
+      continue;
+
+    Symbol<E> &sym = *file.symbols[rel.r_sym];
+    u8 *loc = base + rel.r_offset;
+
+    u64 S = sym.get_addr(ctx);
+    u64 A = rel.r_addend;
+    u64 P = get_addr() + rel.r_offset;
+    u64 G = sym.get_got_addr(ctx) - ctx.gotplt->shdr.sh_addr;
+    u64 GOT = ctx.gotplt->shdr.sh_addr;
+
+    auto check = [&](i64 val, i64 lo, i64 hi) {
+      check_range(ctx, i, val, lo, hi);
+    };
+
+    auto write32 = [&](u64 val) {
+      check(val, 0, 1LL << 32);
+      *(ul32 *)loc = val;
+    };
+
+    auto write32s = [&](u64 val) {
+      check(val, -(1LL << 31), 1LL << 31);
+      *(ul32 *)loc = val;
+    };
+
+    switch (rel.r_type) {
+    case R_X86_64_8:
+      check(S + A, 0, 1 << 8);
+      *loc = S + A;
+      break;
+    case R_X86_64_16:
+      check(S + A, 0, 1 << 16);
+      *(ul16 *)loc = S + A;
+      break;
+    case R_X86_64_32:
+      write32(S + A);
+      break;
+    case R_X86_64_32S:
+      write32s(S + A);
+      break;
+    case R_X86_64_64:
+      break;
+    case R_X86_64_PC8:
+      check(S + A - P, -(1 << 7), 1 << 7);
+      *loc = S + A - P;
+      break;
+    case R_X86_64_PC16:
+      check(S + A - P, -(1 << 15), 1 << 15);
+      *(ul16 *)loc = S + A - P;
+      break;
+    case R_X86_64_PC32:
+    case R_X86_64_PLT32:
+      write32s(S + A - P);
+      break;
+    case R_X86_64_PC64:
+      *(ul64 *)loc = S + A - P;
+      break;
+    case R_X86_64_GOT32:
+      write32(G + A);
+      break;
+    case R_X86_64_GOT64:
+      *(ul64 *)loc = G + A;
+      break;
+    case R_X86_64_GOTOFF64:
+    case R_X86_64_PLTOFF64:
+      *(ul64 *)loc = S + A - GOT;
+      break;
+    case R_X86_64_GOTPC32:
+      write32s(GOT + A - P);
+      break;
+    case R_X86_64_GOTPC64:
+      *(ul64 *)loc = GOT + A - P;
+      break;
+    case R_X86_64_GOTPCREL:
+      write32s(G + GOT + A - P);
+      break;
+    case R_X86_64_GOTPCREL64:
+      *(ul64 *)loc = G + GOT + A - P;
+      break;
+    case R_X86_64_GOTPCRELX:
+    case R_X86_64_REX_GOTPCRELX:
+    case R_X86_64_CODE_4_GOTPCRELX:
+      // We always want to relax GOTPCRELX relocs even if --no-relax
+      // was given because some static PIE runtime code depends on these
+      // relaxations.
+      if (sym.is_pcrel_linktime_const(ctx) && is_int(S + A - P, 32)) {
+        if (u32 insn = relax_gotpcrelx(loc, rel)) {
+          loc[-2] = insn >> 8;
+          loc[-1] = insn;
+          *(ul32 *)loc = S + A - P;
+          break;
+        }
+      }
+      write32s(G + GOT + A - P);
+      break;
+    case R_X86_64_TLSGD:
+      if (sym.has_tlsgd(ctx))
+        write32s(sym.get_tlsgd_addr(ctx) + A - P);
+      else if (sym.has_gottp(ctx))
+        relax_gd_to_ie(loc, rels[++i], sym.get_gottp_addr(ctx) - P);
+      else
+        relax_gd_to_le(loc, rels[++i], S - ctx.tp_addr);
+      break;
+    case R_X86_64_TLSLD:
+      if (ctx.got->has_tlsld(ctx))
+        write32s(ctx.got->get_tlsld_addr(ctx) + A - P);
+      else
+        relax_ld_to_le(loc, rels[++i], ctx.tp_addr - ctx.tls_begin);
+      break;
+    case R_X86_64_DTPOFF32:
+      write32s(S + A - ctx.dtp_addr);
+      break;
+    case R_X86_64_DTPOFF64:
+      *(ul64 *)loc = S + A - ctx.dtp_addr;
+      break;
+    case R_X86_64_TPOFF32:
+      write32s(S + A - ctx.tp_addr);
+      break;
+    case R_X86_64_TPOFF64:
+      *(ul64 *)loc = S + A - ctx.tp_addr;
+      break;
+    case R_X86_64_GOTTPOFF:
+    case R_X86_64_CODE_4_GOTTPOFF:
+      if (sym.has_gottp(ctx)) {
+        write32s(sym.get_gottp_addr(ctx) + A - P);
+      } else {
+        u32 insn = relax_gottpoff(loc, rel);
+        loc[-3] = insn >> 16;
+        loc[-2] = insn >> 8;
+        loc[-1] = insn;
+        write32s(S - ctx.tp_addr);
+      }
+      break;
+    case R_X86_64_CODE_6_GOTTPOFF:
+      write32s(sym.get_gottp_addr(ctx) + A - P);
+      break;
+    case R_X86_64_GOTPC32_TLSDESC:
+    case R_X86_64_CODE_4_GOTPC32_TLSDESC:
+      // x86-64 TLSDESC uses the following code sequence to materialize
+      // a TP-relative address in %rax.
+      //
+      //   lea    0(%rip), %rax
+      //       R_X86_64_GOTPC32_TLSDESC    foo
+      //   call   *(%rax)
+      //       R_X86_64_TLSDESC_CALL       foo
+      //
+      // We may relax the instructions to the following if its TP-relative
+      // address is known at link-time
+      //
+      //   mov     $foo@TPOFF, %rax
+      //   nop
+      //
+      // or to the following if the TP-relative address is known at
+      // process startup time.
+      //
+      //   mov     foo@GOTTPOFF(%rip), %rax
+      //   nop
+      //
+      // We allow the following alternative code sequence too because
+      // LLVM emits such code.
+      //
+      //   lea    0(%rip), %reg
+      //       R_X86_64_GOTPC32_TLSDESC    foo
+      //   mov    %reg, %rax
+      //   call   *(%rax)
+      //       R_X86_64_TLSDESC_CALL       foo
+      if (sym.has_tlsdesc(ctx)) {
+        write32s(sym.get_tlsdesc_addr(ctx) + A - P);
+      } else if (sym.has_gottp(ctx)) {
+        u32 insn = relax_tlsdesc_to_ie(loc, rel);
+        if (!insn)
+          Fatal(ctx) << *this << ": illegal instruction sequence for " << rel;
+        loc[-3] = insn >> 16;
+        loc[-2] = insn >> 8;
+        loc[-1] = insn;
+        write32s(sym.get_gottp_addr(ctx) + A - P);
+      } else {
+        u32 insn = relax_tlsdesc_to_le(loc, rel);
+        if (!insn)
+          Fatal(ctx) << *this << ": illegal instruction sequence for " << rel;
+        loc[-3] = insn >> 16;
+        loc[-2] = insn >> 8;
+        loc[-1] = insn;
+        write32s(S - ctx.tp_addr);
+      }
+      break;
+    case R_X86_64_TLSDESC_CALL:
+      if (!sym.has_tlsdesc(ctx)) {
+        // call *(%rax) -> nop
+        loc[0] = 0x66;
+        loc[1] = 0x90;
+      }
+      break;
+    case R_X86_64_SIZE32:
+      write32(sym.esym().st_size + A);
+      break;
+    case R_X86_64_SIZE64:
+      *(ul64 *)loc = sym.esym().st_size + A;
+      break;
+    default:
+      unreachable();
+    }
+  }
+}
+
+// This function is responsible for applying relocations against
+// non-SHF_ALLOC sections (i.e. sections that are not mapped to memory
+// at runtime).
+//
+// Relocations against non-SHF_ALLOC sections are much easier to
+// handle than that against SHF_ALLOC sections. It is because, since
+// they are not mapped to memory, they don't contain any variable or
+// function and never need PLT or GOT. Non-SHF_ALLOC sections are
+// mostly debug info sections.
+//
+// Relocations against non-SHF_ALLOC sections are not scanned by
+// scan_relocations.
+template <>
+void InputSection<E>::apply_reloc_nonalloc(Context<E> &ctx, u8 *base) {
+  std::span<const ElfRel<E>> rels = get_rels(ctx);
+
+  for (i64 i = 0; i < rels.size(); i++) {
+    const ElfRel<E> &rel = rels[i];
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
+      continue;
+
+    Symbol<E> &sym = *file.symbols[rel.r_sym];
+    u8 *loc = base + rel.r_offset;
+
+    SectionFragment<E> *frag;
+    i64 frag_addend;
+    std::tie(frag, frag_addend) = get_fragment(ctx, rel);
+
+    u64 S = frag ? frag->get_addr(ctx) : sym.get_addr(ctx);
+    u64 A = frag ? frag_addend : (i64)rel.r_addend;
+
+    auto check = [&](i64 val, i64 lo, i64 hi) {
+      check_range(ctx, i, val, lo, hi);
+    };
+
+    auto write32 = [&](u64 val) {
+      check(val, 0, 1LL << 32);
+      *(ul32 *)loc = val;
+    };
+
+    auto write32s = [&](u64 val) {
+      check(val, -(1LL << 31), 1LL << 31);
+      *(ul32 *)loc = val;
+    };
+
+    switch (rel.r_type) {
+    case R_X86_64_8:
+      check(S + A, 0, 1 << 8);
+      *loc = S + A;
+      break;
+    case R_X86_64_16:
+      check(S + A, 0, 1 << 16);
+      *(ul16 *)loc = S + A;
+      break;
+    case R_X86_64_32:
+      write32(S + A);
+      break;
+    case R_X86_64_32S:
+      write32s(S + A);
+      break;
+    case R_X86_64_64:
+      if (std::optional<u64> val = get_tombstone(sym, frag))
+        *(ul64 *)loc = *val;
+      else
+        *(ul64 *)loc = S + A;
+      break;
+    case R_X86_64_DTPOFF32:
+      if (std::optional<u64> val = get_tombstone(sym, frag))
+        *(ul32 *)loc = *val;
+      else
+        write32s(S + A - ctx.dtp_addr);
+      break;
+    case R_X86_64_DTPOFF64:
+      if (std::optional<u64> val = get_tombstone(sym, frag))
+        *(ul64 *)loc = *val;
+      else
+        *(ul64 *)loc = S + A - ctx.dtp_addr;
+      break;
+    case R_X86_64_GOTOFF64:
+      *(ul64 *)loc = S + A - ctx.gotplt->shdr.sh_addr;
+      break;
+    case R_X86_64_GOTPC64:
+      // PC-relative relocation doesn't make sense for non-memory-allocated
+      // section, but GCC 6.3.0 seems to create this reloc for
+      // _GLOBAL_OFFSET_TABLE_.
+      *(ul64 *)loc = ctx.gotplt->shdr.sh_addr + A;
+      break;
+    case R_X86_64_SIZE32:
+      write32(sym.esym().st_size + A);
+      break;
+    case R_X86_64_SIZE64:
+      *(ul64 *)loc = sym.esym().st_size + A;
+      break;
+    default:
+      Fatal(ctx) << *this << ": invalid relocation for non-allocated sections: "
+                 << rel;
+      break;
+    }
+  }
+}
+
+// Linker has to create data structures in an output file to apply
+// some type of relocations. For example, if a relocation refers a GOT
+// or a PLT entry of a symbol, linker has to create an entry in .got
+// or in .plt for that symbol. In order to fix the file layout, we
+// need to scan relocations.
+template <>
+void InputSection<E>::scan_relocations(Context<E> &ctx) {
+  assert(shdr().sh_flags & SHF_ALLOC);
+  std::span<const ElfRel<E>> rels = get_rels(ctx);
+
+  // Scan relocations
+  for (i64 i = 0; i < rels.size(); i++) {
+    const ElfRel<E> &rel = rels[i];
+    if (rel.r_type == R_NONE || record_undef_error(ctx, rel))
+      continue;
+
+    Symbol<E> &sym = *file.symbols[rel.r_sym];
+    u8 *loc = (u8 *)(contents.data() + rel.r_offset);
+
+    if (sym.is_ifunc())
+      sym.flags |= NEEDS_GOT | NEEDS_PLT;
+
+    if (rel.r_type == R_X86_64_TLSGD || rel.r_type == R_X86_64_TLSLD) {
+      if (i + 1 == rels.size())
+        Fatal(ctx) << *this << ": " << rel
+                   << " must be followed by PLT or GOTPCREL";
+
+      if (u32 ty = rels[i + 1].r_type;
+          ty != R_X86_64_PLT32 && ty != R_X86_64_PC32 &&
+          ty != R_X86_64_PLTOFF64 && ty != R_X86_64_GOTPCREL &&
+          ty != R_X86_64_GOTPCRELX)
+        Fatal(ctx) << *this << ": " << rel
+                   << " must be followed by PLT or GOTPCREL";
+    }
+
+    switch (rel.r_type) {
+    case R_X86_64_8:
+    case R_X86_64_16:
+    case R_X86_64_32:
+    case R_X86_64_32S:
+      scan_absrel(ctx, sym, rel);
+      break;
+    case R_X86_64_PC8:
+    case R_X86_64_PC16:
+    case R_X86_64_PC32:
+    case R_X86_64_PC64:
+      scan_pcrel(ctx, sym, rel);
+      break;
+    case R_X86_64_GOT32:
+    case R_X86_64_GOT64:
+    case R_X86_64_GOTPC32:
+    case R_X86_64_GOTPC64:
+    case R_X86_64_GOTPCREL:
+    case R_X86_64_GOTPCREL64:
+    case R_X86_64_GOTPCRELX:
+    case R_X86_64_REX_GOTPCRELX:
+    case R_X86_64_CODE_4_GOTPCRELX:
+      sym.flags |= NEEDS_GOT;
+      break;
+    case R_X86_64_PLT32:
+    case R_X86_64_PLTOFF64:
+      if (sym.is_imported)
+        sym.flags |= NEEDS_PLT;
+      break;
+    case R_X86_64_TLSGD:
+      if (ctx.arg.static_ || (ctx.arg.relax && sym.is_tprel_linktime_const(ctx))) {
+        // We always relax if -static because libc.a doesn't contain
+        // __tls_get_addr().
+        i++;
+      } else if (ctx.arg.relax && sym.is_tprel_runtime_const(ctx)) {
+        sym.flags |= NEEDS_GOTTP;
+        i++;
+      } else {
+        sym.flags |= NEEDS_TLSGD;
+      }
+      break;
+    case R_X86_64_TLSLD:
+      // We always relax if -static because libc.a doesn't contain
+      // __tls_get_addr().
+      if (ctx.arg.static_ || (ctx.arg.relax && !ctx.arg.shared))
+        i++;
+      else
+        ctx.needs_tlsld = true;
+      break;
+    case R_X86_64_GOTTPOFF:
+    case R_X86_64_CODE_4_GOTTPOFF:
+      if (!ctx.arg.relax || !sym.is_tprel_linktime_const(ctx) ||
+          !relax_gottpoff(loc, rel))
+        sym.flags |= NEEDS_GOTTP;
+      break;
+    case R_X86_64_CODE_6_GOTTPOFF:
+      sym.flags |= NEEDS_GOTTP;
+      break;
+    case R_X86_64_TLSDESC_CALL:
+      scan_tlsdesc(ctx, sym);
+      break;
+    case R_X86_64_TPOFF32:
+    case R_X86_64_TPOFF64:
+      check_tlsle(ctx, sym, rel);
+      break;
+    case R_X86_64_64:
+    case R_X86_64_GOTOFF64:
+    case R_X86_64_DTPOFF32:
+    case R_X86_64_DTPOFF64:
+    case R_X86_64_SIZE32:
+    case R_X86_64_SIZE64:
+    case R_X86_64_GOTPC32_TLSDESC:
+    case R_X86_64_CODE_4_GOTPC32_TLSDESC:
+      break;
+    default:
+      Error(ctx) << *this << ": unknown relocation: " << rel;
+    }
+  }
+}
+
+// Intel CET is a relatively new CPU feature to enhance security by
+// protecting control flow integrity. If the feature is enabled, indirect
+// branches (i.e. branch instructions that take a register instead of an
+// immediate) must land on a "landing pad" instruction, or a CPU-level fault
+// will raise. That prevents an attacker to branch to a middle of a random
+// function, making ROP or JOP much harder to conduct.
+//
+// On x86-64, the landing pad instruction is ENDBR64. That is actually a
+// repurposed NOP instruction to provide binary compatibility with older
+// hardware that doesn't support CET.
+//
+// The problem here is that the compiler always emits a landing pad at the
+// beginning fo a global function because it doesn't know whether or not the
+// function's address is taken in other translation units. As a result, the
+// resulting binary contains more landing pads than necessary.
+//
+// This function rewrites a landing pad with a nop if the function's address
+// was not actually taken. We can do what the compiler cannot because we
+// know about all translation units.
+void rewrite_endbr(Context<E> &ctx) {
+  Timer t(ctx, "rewrite_endbr");
+
+  constexpr u8 endbr64[] = {0xf3, 0x0f, 0x1e, 0xfa};
+  constexpr u8 nop[] = {0x0f, 0x1f, 0x40, 0x00};
+
+  // Rewrite all endbr64 instructions referred to by function symbols with
+  // NOPs. We handle only global symbols because the compiler doesn't emit
+  // an endbr64 for a file-scoped function in the first place if its address
+  // is not taken within the file.
+  tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
+    for (Symbol<E> *sym : file->get_global_syms()) {
+      if (sym->file == file && sym->esym().st_type == STT_FUNC) {
+        if (InputSection<E> *isec = sym->get_input_section();
+            isec && (isec->shdr().sh_flags & SHF_EXECINSTR)) {
+          if (OutputSection<E> *osec = isec->output_section) {
+            u8 *buf = ctx.buf + osec->shdr.sh_offset + isec->offset + sym->value;
+            if (memcmp(buf, endbr64, 4) == 0)
+              memcpy(buf, nop, 4);
+          }
+        }
+      }
+    }
+  });
+
+  auto write_back = [&](InputSection<E> *isec, i64 offset) {
+    // If isec has an endbr64 at a given offset, copy that instruction to
+    // the output buffer, possibly overwriting a nop written in the above
+    // loop.
+    if (isec && isec->output_section &&
+        (isec->shdr().sh_flags & SHF_EXECINSTR) &&
+        0 <= offset && offset <= isec->contents.size() - 4 &&
+        memcmp(isec->contents.data() + offset, endbr64, 4) == 0)
+      memcpy(ctx.buf + isec->output_section->shdr.sh_offset + isec->offset + offset,
+             endbr64, 4);
+  };
+
+  // Write back endbr64 instructions if they are referred to by address-taking
+  // relocations.
+  tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
+    for (std::unique_ptr<InputSection<E>> &isec : file->sections) {
+      if (isec && isec->is_alive && (isec->shdr().sh_flags & SHF_ALLOC)) {
+        for (const ElfRel<E> &rel : isec->get_rels(ctx)) {
+          if (!is_func_call_rel(rel)) {
+            Symbol<E> *sym = file->symbols[rel.r_sym];
+            if (sym->esym().st_type == STT_SECTION)
+              write_back(sym->get_input_section(), rel.r_addend);
+            else
+              write_back(sym->get_input_section(), sym->value);
+          }
+        }
+      }
+    }
+  });
+
+  // We record addresses of some symbols in the ELF header, .dynamic or in
+  // .dynsym. We need to retain endbr64s for such symbols.
+  auto keep = [&](Symbol<E> *sym) {
+    if (sym)
+      write_back(sym->get_input_section(), sym->value);
+  };
+
+  keep(ctx.arg.entry);
+  keep(ctx.arg.init);
+  keep(ctx.arg.fini);
+
+  if (ctx.dynsym)
+    for (Symbol<E> *sym : ctx.dynsym->symbols)
+      if (sym && sym->is_exported)
+        keep(sym);
+}
+
+} // namespace mold
+
+#endif

src/archive-file.cc

@@ -23,13 +23,11 @@
 // see the contents of libc.a by running `ar t
 // /usr/lib/x86_64-linux-gnu/libc.a`.
 
-#pragma once
-
-#include "common.h"
-#include "filetype.h"
+#include "mold.h"
 
 namespace mold {
 
+namespace {
 struct ArHdr {
   char ar_name[16];
   char ar_date[12];
@@ -75,10 +73,11 @@ struct ArHdr {
     return {ar_name, sizeof(ar_name)};
   }
 };
+}
 
-template <typename Context, typename MappedFile>
+template <typename E>
 std::vector<MappedFile *>
-read_thin_archive_members(Context &ctx, MappedFile *mf) {
+read_thin_archive_members(Context<E> &ctx, MappedFile *mf) {
   u8 *begin = mf->data;
   u8 *data = begin + 8;
   std::vector<MappedFile *> vec;
@@ -116,16 +115,17 @@ read_thin_archive_members(Context &ctx, MappedFile *mf) {
       continue;
 
     std::string path = name.starts_with('/') ?
-      name : (filepath(mf->name).parent_path() / name).string();
-    vec.push_back(MappedFile::must_open(ctx, path));
+      name : (path_dirname(mf->name) / name).string();
+    vec.push_back(must_open_file(ctx, path));
     vec.back()->thin_parent = mf;
     data = body;
   }
   return vec;
 }
 
-template <typename Context, typename MappedFile>
-std::vector<MappedFile *> read_fat_archive_members(Context &ctx, MappedFile *mf) {
+template <typename E>
+std::vector<MappedFile *>
+read_fat_archive_members(Context<E> &ctx, MappedFile *mf) {
   u8 *begin = mf->data;
   u8 *data = begin + 8;
   std::vector<MappedFile *> vec;
@@ -162,16 +162,27 @@ std::vector<MappedFile *> read_fat_archive_members(Context &ctx, MappedFile *mf)
   return vec;
 }
 
-template <typename Context, typename MappedFile>
-std::vector<MappedFile *> read_archive_members(Context &ctx, MappedFile *mf) {
-  switch (get_file_type(ctx, mf)) {
-  case FileType::AR:
+template <typename E>
+std::vector<MappedFile *>
+read_archive_members(Context<E> &ctx, MappedFile *mf) {
+  std::string_view str = mf->get_contents();
+
+  if (str.starts_with("!<arch>\n"))
     return read_fat_archive_members(ctx, mf);
-  case FileType::THIN_AR:
-    return read_thin_archive_members(ctx, mf);
-  default:
-    unreachable();
-  }
+
+  assert(str.starts_with("!<thin>\n"));
+  return read_thin_archive_members(ctx, mf);
 }
 
+using E = MOLD_TARGET;
+
+template std::vector<MappedFile *>
+read_thin_archive_members(Context<E> &, MappedFile *);
+
+template std::vector<MappedFile *>
+read_fat_archive_members(Context<E> &, MappedFile *);
+
+template std::vector<MappedFile *>
+read_archive_members(Context<E> &, MappedFile *);
+
 } // namespace mold

src/entry.cc

@@ -0,0 +1,32 @@
+#include "config.h"
+#include "mold.h"
+#include "mold-git-hash.h"
+
+#if MOLD_USE_MIMALLOC
+# include <mimalloc.h>
+#endif
+
+#if MOLD_USE_SYSTEM_MIMALLOC
+// Including mimalloc-new-delete.h overrides the new/delete operators.
+// We need it only when using mimalloc as a dynamic library.
+// This header should be included in only one source file, so we do
+// it in this file.
+# include <mimalloc-new-delete.h>
+#endif
+
+std::string mold::mold_version =
+#ifdef MOLD_GIT_HASH
+  "mold " MOLD_VERSION " (" MOLD_GIT_HASH "; compatible with GNU ld)";
+#else
+  "mold " MOLD_VERSION " (compatible with GNU ld)";
+#endif
+
+int main(int argc, char **argv) {
+#if MOLD_USE_MIMALLOC
+  // Silence mimalloc warnings that users can ignore
+  mi_option_disable(mi_option_verbose);
+  mi_option_disable(mi_option_show_errors);
+#endif
+
+  return mold::mold_main<mold::MOLD_FIRST_TARGET>(argc, argv);
+}

src/error.cc

@@ -0,0 +1,55 @@
+#include "mold.h"
+
+namespace mold {
+
+static std::string_view fatal_mono = "mold: fatal: ";
+static std::string_view fatal_color = "mold: \033[0;1;31mfatal:\033[0m ";
+static std::string_view error_mono = "mold: error: ";
+static std::string_view error_color = "mold: \033[0;1;31merror:\033[0m ";
+static std::string_view warning_mono = "mold: warning: ";
+static std::string_view warning_color = "mold: \033[0;1;35mwarning:\033[0m ";
+
+template <typename E>
+Fatal<E>::Fatal(Context<E> &ctx) {
+  out << (ctx.arg.color_diagnostics ? fatal_color : fatal_mono);
+}
+
+template <typename E>
+[[noreturn]] Fatal<E>::~Fatal() {
+  out.emit();
+  cleanup();
+  _exit(1);
+}
+
+template <typename E>
+Error<E>::Error(Context<E> &ctx) {
+  if (ctx.arg.noinhibit_exec) {
+    out << (ctx.arg.color_diagnostics ? warning_color : warning_mono);
+  } else {
+    out << (ctx.arg.color_diagnostics ? error_color : error_mono);
+    ctx.has_error = true;
+  }
+}
+
+template <typename E>
+Warn<E>::Warn(Context<E> &ctx) {
+  if (ctx.arg.suppress_warnings)
+    return;
+
+  out.emplace(std::cerr);
+
+  if (ctx.arg.fatal_warnings) {
+    *out << (ctx.arg.color_diagnostics ? error_color : error_mono);
+    ctx.has_error = true;
+  } else {
+    *out << (ctx.arg.color_diagnostics ? warning_color : warning_mono);
+  }
+}
+
+using E = MOLD_TARGET;
+
+template class Fatal<E>;
+template class Error<E>;
+template class Warn<E>;
+
+} // namespace mold

src/filetype.cc

@@ -1,39 +1,19 @@
-#pragma once
-
-#include "common.h"
-#include "../elf/elf.h"
+#include "mold.h"
 
 namespace mold {
 
-enum class FileType {
-  UNKNOWN,
-  EMPTY,
-  ELF_OBJ,
-  ELF_DSO,
-  MACH_OBJ,
-  MACH_EXE,
-  MACH_DYLIB,
-  MACH_BUNDLE,
-  MACH_UNIVERSAL,
-  AR,
-  THIN_AR,
-  TAPI,
-  TEXT,
-  GCC_LTO_OBJ,
-  LLVM_BITCODE,
-};
+static bool is_text_file(MappedFile *mf) {
+  auto istext = [](char c) {
+    return isprint(c) || c == '\n' || c == '\t';
+  };
 
-template <typename MappedFile>
-bool is_text_file(MappedFile *mf) {
   u8 *data = mf->data;
-  return mf->size >= 4 && isprint(data[0]) && isprint(data[1]) &&
-         isprint(data[2]) && isprint(data[3]);
+  return mf->size >= 4 && istext(data[0]) && istext(data[1]) &&
+         istext(data[2]) && istext(data[3]);
 }
 
-template <typename E, typename Context, typename MappedFile>
-inline bool is_gcc_lto_obj(Context &ctx, MappedFile *mf) {
-  using namespace mold::elf;
-
+template <typename E>
+static bool is_gcc_lto_obj(MappedFile *mf, bool has_gcc_plugin) {
   const char *data = mf->get_contents().data();
   ElfEhdr<E> &ehdr = *(ElfEhdr<E> *)data;
   ElfShdr<E> *sh_begin = (ElfShdr<E> *)(data + ehdr.e_shoff);
@@ -50,10 +30,10 @@ inline bool is_gcc_lto_obj(Context &ctx, MappedFile *mf) {
     // the LTO linker plugin is available and falls back as regular
     // objects otherwise. GCC FAT LTO object can be identified by the
     // presence of `.gcc.lto_.symtab` section.
-    if (!ctx.arg.plugin.empty()) {
+    if (has_gcc_plugin) {
       std::string_view name = data + shdrs[shstrtab_idx].sh_offset + sec.sh_name;
       if (name.starts_with(".gnu.lto_.symtab."))
-      return true;
+        return true;
     }
 
     if (sec.sh_type != SHT_SYMTAB)
@@ -85,15 +65,18 @@ inline bool is_gcc_lto_obj(Context &ctx, MappedFile *mf) {
   return false;
 }
 
-template <typename Context, typename MappedFile>
-FileType get_file_type(Context &ctx, MappedFile *mf) {
-  using namespace elf;
-
+template <typename E>
+FileType get_file_type(Context<E> &ctx, MappedFile *mf) {
   std::string_view data = mf->get_contents();
-
   if (data.empty())
     return FileType::EMPTY;
 
+  // GCC FAT LTO objects can be linked as regular ELF objects. If the active
+  // plugin is LLVM's, treat them as regular objects so that we can fall back
+  // to native code instead of routing them through GCC LTO handling.
+  bool has_gcc_plugin = !ctx.arg.plugin.empty() &&
+                        ctx.arg.plugin.find("LLVMgold.") == std::string_view::npos;
+
   if (data.starts_with("\177ELF")) {
     u8 byte_order = ((ElfEhdr<I386> *)data.data())->e_ident[EI_DATA];
 
@@ -102,10 +85,10 @@ FileType get_file_type(Context &ctx, MappedFile *mf) {
 
       if (ehdr.e_type == ET_REL) {
         if (ehdr.e_ident[EI_CLASS] == ELFCLASS32) {
-          if (is_gcc_lto_obj<I386>(ctx, mf))
+          if (is_gcc_lto_obj<I386>(mf, has_gcc_plugin))
             return FileType::GCC_LTO_OBJ;
         } else {
-          if (is_gcc_lto_obj<X86_64>(ctx, mf))
+          if (is_gcc_lto_obj<X86_64>(mf, has_gcc_plugin))
             return FileType::GCC_LTO_OBJ;
         }
         return FileType::ELF_OBJ;
@@ -118,10 +101,10 @@ FileType get_file_type(Context &ctx, MappedFile *mf) {
 
       if (ehdr.e_type == ET_REL) {
         if (ehdr.e_ident[EI_CLASS] == ELFCLASS32) {
-          if (is_gcc_lto_obj<M68K>(ctx, mf))
+          if (is_gcc_lto_obj<M68K>(mf, has_gcc_plugin))
             return FileType::GCC_LTO_OBJ;
         } else {
-          if (is_gcc_lto_obj<SPARC64>(ctx, mf))
+          if (is_gcc_lto_obj<SPARC64>(mf, has_gcc_plugin))
             return FileType::GCC_LTO_OBJ;
         }
         return FileType::ELF_OBJ;
@@ -133,28 +116,10 @@ FileType get_file_type(Context &ctx, MappedFile *mf) {
     return FileType::UNKNOWN;
   }
 
-  if (data.starts_with("\xcf\xfa\xed\xfe")) {
-    switch (*(ul32 *)(data.data() + 12)) {
-    case 1: // MH_OBJECT
-      return FileType::MACH_OBJ;
-    case 2: // MH_EXECUTE
-      return FileType::MACH_EXE;
-    case 6: // MH_DYLIB
-      return FileType::MACH_DYLIB;
-    case 8: // MH_BUNDLE
-      return FileType::MACH_BUNDLE;
-    }
-    return FileType::UNKNOWN;
-  }
-
   if (data.starts_with("!<arch>\n"))
     return FileType::AR;
   if (data.starts_with("!<thin>\n"))
     return FileType::THIN_AR;
-  if (data.starts_with("--- !tapi-tbd"))
-    return FileType::TAPI;
-  if (data.starts_with("\xca\xfe\xba\xbe"))
-    return FileType::MACH_UNIVERSAL;
   if (is_text_file(mf))
     return FileType::TEXT;
   if (data.starts_with("\xde\xc0\x17\x0b"))
@@ -164,30 +129,79 @@ FileType get_file_type(Context &ctx, MappedFile *mf) {
   return FileType::UNKNOWN;
 }
 
-inline std::string filetype_to_string(FileType type) {
-  switch (type) {
-  case FileType::UNKNOWN: return "UNKNOWN";
-  case FileType::EMPTY: return "EMPTY";
-  case FileType::ELF_OBJ: return "ELF_OBJ";
-  case FileType::ELF_DSO: return "ELF_DSO";
-  case FileType::MACH_EXE: return "MACH_EXE";
-  case FileType::MACH_OBJ: return "MACH_OBJ";
-  case FileType::MACH_DYLIB: return "MACH_DYLIB";
-  case FileType::MACH_BUNDLE: return "MACH_BUNDLE";
-  case FileType::MACH_UNIVERSAL: return "MACH_UNIVERSAL";
-  case FileType::AR: return "AR";
-  case FileType::THIN_AR: return "THIN_AR";
-  case FileType::TAPI: return "TAPI";
-  case FileType::TEXT: return "TEXT";
-  case FileType::GCC_LTO_OBJ: return "GCC_LTO_OBJ";
-  case FileType::LLVM_BITCODE: return "LLVM_BITCODE";
+static std::string_view get_elf_type(u8 *buf) {
+  bool is_le = (buf[EI_DATA] == ELFDATA2LSB);
+  bool is_64 = (buf[EI_CLASS] == ELFCLASS64);
+
+  auto *ehdr_le = (ElfEhdr<I386> *)buf;
+  auto *ehdr_be = (ElfEhdr<M68K> *)buf;
+
+  switch (is_le ? ehdr_le->e_machine : ehdr_be->e_machine) {
+  case EM_386:
+    return I386::name;
+  case EM_X86_64:
+    return X86_64::name;
+  case EM_ARM:
+    return is_le ? ARM32LE::name : ARM32BE::name;
+  case EM_AARCH64:
+    return is_le ? ARM64LE::name : ARM64BE::name;
+  case EM_RISCV:
+    if (is_le)
+      return is_64 ? RV64LE::name : RV32LE::name;
+    return is_64 ? RV64BE::name : RV32BE::name;
+  case EM_PPC:
+    return PPC32::name;
+  case EM_PPC64:
+    return is_le ? PPC64V2::name : PPC64V1::name;
+  case EM_S390X:
+    return S390X::name;
+  case EM_SPARC64:
+    return SPARC64::name;
+  case EM_68K:
+    return M68K::name;
+  case EM_SH:
+    return is_le ? SH4LE::name : SH4BE::name;
+  case EM_LOONGARCH:
+    return is_64 ? LOONGARCH64::name : LOONGARCH32::name;
+  default:
+    return "";
   }
-  return "UNKNOWN";
 }
 
-inline std::ostream &operator<<(std::ostream &out, FileType type) {
-  out << filetype_to_string(type);
-  return out;
+// Read the beginning of a given file and returns its machine type
+// (e.g. EM_X86_64 or EM_386).
+template <typename E>
+std::string_view
+get_machine_type(Context<E> &ctx, ReaderContext &rctx, MappedFile *mf) {
+  switch (get_file_type(ctx, mf)) {
+  case FileType::ELF_OBJ:
+  case FileType::ELF_DSO:
+  case FileType::GCC_LTO_OBJ:
+    return get_elf_type(mf->data);
+  case FileType::AR:
+    for (MappedFile *child : read_fat_archive_members(ctx, mf))
+      if (FileType ty = get_file_type(ctx, child);
+          ty == FileType::ELF_OBJ || ty == FileType::GCC_LTO_OBJ)
+        return get_elf_type(child->data);
+    return "";
+  case FileType::THIN_AR:
+    for (MappedFile *child : read_thin_archive_members(ctx, mf))
+      if (FileType ty = get_file_type(ctx, child);
+          ty == FileType::ELF_OBJ || ty == FileType::GCC_LTO_OBJ)
+        return get_elf_type(child->data);
+    return "";
+  case FileType::TEXT:
+    return Script(ctx, mf, &rctx).get_script_output_type();
+  default:
+    return "";
+  }
 }
 
+using E = MOLD_TARGET;
+
+template FileType get_file_type(Context<E> &, MappedFile *);
+
+template std::string_view
+get_machine_type(Context<E> &, ReaderContext &, MappedFile *);
+
 } // namespace mold

src/gc-sections.cc

@@ -0,0 +1,249 @@
+// This file implements a mark-sweep garbage collector for -gc-sections.
+// In this algorithm, vertices are sections and edges are relocations.
+// Any section that is reachable from a root section is considered alive.
+
+#include "mold.h"
+
+#include <fstream>
+#include <tbb/concurrent_unordered_map.h>
+#include <tbb/concurrent_vector.h>
+#include <tbb/parallel_for_each.h>
+
+namespace mold {
+
+template <typename E>
+static bool should_keep(Context<E> &ctx, const InputSection<E> &isec) {
+  u32 type = isec.shdr().sh_type;
+  u32 flags = isec.shdr().sh_flags;
+  if constexpr (is_ppc32<E>)
+    if (isec.name == ".got2")
+      return true;
+
+  // KEEP'ed by a linker script
+  if (!isec.file.script_match.empty()) {
+    i32 rank = isec.file.script_match[isec.shndx];
+    if (rank != -1 && ctx.script_ranks[rank].keep)
+      return true;
+  }
+
+  return (flags & SHF_GNU_RETAIN) ||
+         type == SHT_NOTE ||
+         type == SHT_INIT_ARRAY ||
+         type == SHT_FINI_ARRAY ||
+         type == SHT_PREINIT_ARRAY ||
+         isec.name.starts_with(".ctors") ||
+         isec.name.starts_with(".dtors") ||
+         isec.name.starts_with(".init") ||
+         isec.name.starts_with(".fini");
+}
+
+// Sections whose names are valid C identifiers can be referenced via
+// __start_<name>/__stop_<name> symbols, which the linker synthesizes.
+// Such sections must be kept alive only if such a marker symbol is
+// referenced from a live section. This map lets us find all sections
+// of a given name when we encounter such a reference during marking.
+template <typename E>
+using StartStopMap =
+  tbb::concurrent_unordered_multimap<std::string_view, InputSection<E> *>;
+
+template <typename E>
+static StartStopMap<E> build_start_stop_map(Context<E> &ctx) {
+  StartStopMap<E> map;
+  tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
+    for (std::unique_ptr<InputSection<E>> &isec : file->sections)
+      if (isec && isec->is_alive && (isec->shdr().sh_flags & SHF_ALLOC) &&
+          is_c_identifier(isec->name))
+        map.insert({isec->name, isec.get()});
+  });
+  return map;
+}
+
+template <typename E>
+static bool mark_section(InputSection<E> *isec) {
+  return isec && isec->is_alive && !isec->is_visited.test_and_set();
+}
+
+template <typename E>
+static tbb::concurrent_vector<InputSection<E> *>
+collect_root_set(Context<E> &ctx) {
+  Timer t(ctx, "collect_root_set");
+  tbb::concurrent_vector<InputSection<E> *> rootset;
+
+  auto enqueue_section = [&](InputSection<E> *isec) {
+    if (mark_section(isec))
+      rootset.push_back(isec);
+  };
+
+  auto enqueue_symbol = [&](Symbol<E> *sym) {
+    if (sym) {
+      if (SectionFragment<E> *frag = sym->get_frag())
+        frag->is_alive = true;
+      else
+        enqueue_section(sym->get_input_section());
+    }
+  };
+
+  // Add sections that are not subject to garbage collection.
+  tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
+    for (std::unique_ptr<InputSection<E>> &isec : file->sections) {
+      if (!isec || !isec->is_alive)
+        continue;
+
+      // --gc-sections discards only SHF_ALLOC sections. If you want to
+      // reduce the amount of non-memory-mapped segments, you should
+      // use `strip` command, compile without debug info or use
+      // --strip-all linker option.
+      if (!(isec->shdr().sh_flags & SHF_ALLOC)) {
+        isec->is_visited = true;
+        continue;
+      }
+
+      if (should_keep(ctx, *isec))
+        enqueue_section(isec.get());
+    }
+  });
+
+  // Add sections containing gc root or exported symbols
+  tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
+    for (Symbol<E> *sym : file->symbols)
+      if (sym->file == file && (sym->gc_root || sym->is_exported))
+        enqueue_symbol(sym);
+  });
+
+  // .eh_frame consists of variable-length records called CIE and FDE
+  // records, and they are a unit of inclusion or exclusion.
+  // We just keep all CIEs and everything that are referenced by them.
+  tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
+    for (CieRecord<E> &cie : file->cies)
+      for (const ElfRel<E> &rel : cie.get_rels())
+        enqueue_symbol(file->symbols[rel.r_sym]);
+  });
+
+  return rootset;
+}
+
+static std::string_view start_stop_name(std::string_view sym) {
+  if (sym.starts_with("__start_"))
+    return sym.substr(8);
+  if (sym.starts_with("__stop_"))
+    return sym.substr(7);
+  return "";
+}
+
+template <typename E>
+static void visit_section(Context<E> &ctx, InputSection<E> *isec,
+                          tbb::feeder<InputSection<E> *> &feeder, i64 depth,
+                          const StartStopMap<E> &start_stop_map) {
+  assert(isec->is_visited);
+
+  // Mark a section alive. For better performacne, we don't call
+  // `feeder.add` too often.
+  auto mark = [&](InputSection<E> *sec) {
+    if (mark_section(sec)) {
+      if (depth < 3)
+        visit_section(ctx, sec, feeder, depth + 1, start_stop_map);
+      else
+        feeder.add(sec);
+    }
+  };
+
+  // If this is a text section, .eh_frame may contain records
+  // describing how to handle exceptions for that function.
+  // We want to keep associated .eh_frame records.
+  for (FdeRecord<E> &fde : isec->get_fdes())
+    for (const ElfRel<E> &rel : fde.get_rels(isec->file).subspan(1))
+      if (Symbol<E> *sym = isec->file.symbols[rel.r_sym])
+        mark(sym->get_input_section());
+
+  for (const ElfRel<E> &rel : isec->get_rels(ctx)) {
+    // Symbol can refer to either a section fragment or an input section.
+    Symbol<E> &sym = *isec->file.symbols[rel.r_sym];
+    if (SectionFragment<E> *frag = sym.get_frag()) {
+      frag->is_alive = true;
+      continue;
+    }
+
+    mark(sym.get_input_section());
+
+    // A reference to __start_<name> or __stop_<name> keeps every section
+    // named <name> alive, mirroring how those symbols are defined.
+    if (std::string_view sec = start_stop_name(sym.name());
+        !sec.empty()) {
+      auto [i, end] = start_stop_map.equal_range(sec);
+      for (; i != end; ++i)
+        mark(i->second);
+    }
+  }
+
+  if constexpr (is_arm32<E>)
+    mark(isec->extra.exidx);
+}
+
+// Mark all reachable sections
+template <typename E>
+static void mark(Context<E> &ctx,
+                 tbb::concurrent_vector<InputSection<E> *> &rootset,
+                 const StartStopMap<E> &start_stop_map) {
+  Timer t(ctx, "mark");
+
+  tbb::parallel_for_each(rootset, [&](InputSection<E> *isec,
+                                      tbb::feeder<InputSection<E> *> &feeder) {
+    visit_section(ctx, isec, feeder, 0, start_stop_map);
+  });
+}
+
+// Remove unreachable sections
+template <typename E>
+static void sweep(Context<E> &ctx) {
+  Timer t(ctx, "sweep");
+
+  std::vector<std::vector<InputSection<E> *>> sections(ctx.objs.size());
+
+  tbb::parallel_for((i64)0, (i64)ctx.objs.size(), [&](i64 i) {
+    ObjectFile<E> &file = *ctx.objs[i];
+
+    for (std::unique_ptr<InputSection<E>> &isec : file.sections) {
+      if (isec && isec->is_alive && !isec->is_visited) {
+        isec->kill();
+        sections[i].push_back(isec.get());
+      }
+    }
+  });
+
+  std::string &path = ctx.arg.print_gc_sections;
+
+  if (!path.empty()) {
+    std::ostream *out = &std::cout;
+    std::ofstream file;
+
+    if (path != "-") {
+      file.open(path);
+      if (file.fail())
+        Fatal(ctx) << "--print-gc-sections: cannot open " << path << ": "
+                   << errno_string();
+      out = &file;
+    }
+
+    i64 saved_bytes = 0;
+    for (std::span<InputSection<E> *> vec : sections)
+      for (InputSection<E> *isec : vec)
+        *out << "removing unused section " << *isec << '\n';
+
+    *out << "GC saved " << saved_bytes << " bytes\n";
+  }
+}
+
+template <typename E>
+void gc_sections(Context<E> &ctx) {
+  Timer t(ctx, "gc");
+  tbb::concurrent_vector<InputSection<E> *> rootset = collect_root_set(ctx);
+  StartStopMap<E> start_stop_map = build_start_stop_map(ctx);
+  mark(ctx, rootset, start_stop_map);
+  sweep(ctx);
+}
+
+using E = MOLD_TARGET;
+
+template void gc_sections(Context<E> &ctx);
+
+} // namespace mold

src/gdb-index.cc

@@ -0,0 +1,808 @@
+// This file contains code to read DWARF debug info to create .gdb_index.
+//
+// .gdb_index is an optional section to speed up GNU debugger. It contains
+// two maps: 1) a map from function/variable/type names to compunits, and
+// 2) a map from function address ranges to compunits. gdb uses these
+// maps to quickly find a compunit given a name or an instruction pointer.
+//
+// (Terminology: a compilation unit, often abbreviated as compunit or
+// CU, is a unit of debug info. An input .debug_info section usually
+// contains one compunit, and thus an output .debug_info contains as
+// many compunits as the number of input files.)
+//
+// .gdb_index is not mandatory. All the information in .gdb_index is
+// also in other debug info sections. You can actually create an
+// executable without .gdb_index and later add it using the
+// `gdb-add-index` post-processing tool that comes with gdb.
+//
+// Post-relocated debug section contents are needed to create a
+// .gdb_index. Therefore, we create it after relocating all the other
+// sections. The size of the section is also hard to estimate before
+// applying relocations to debug info sections, so a .gdb_index is
+// placed at the very end of the output file, even after the section
+// header.
+//
+// The mapping from names to compunits is 1:n while the mapping from
+// address ranges to compunits is 1:1. That is, two object files may
+// define the same type name, while there should be no two functions
+// that overlap with each other in memory.
+//
+// .gdb_index contains an on-disk hash table for names, so gdb can
+// lookup names without loading all strings into memory and construct an
+// in-memory hash table.
+//
+// Names are in .debug_gnu_pubnames and .debug_gnu_pubtypes input
+// sections. These sections are created if `-ggnu-pubnames` is given.
+// Besides names, these sections contain attributes for each name so
+// that gdb can distinguish type names from function names, for example.
+//
+// A compunit contains one or more function address ranges. If an
+// object file is compiled without -ffunction-sections, it contains
+// only one .text section and therefore contains a single address range.
+// Such range is typically stored directly to the compunit.
+//
+// If an object file is compiled with -ffunction-sections, it contains
+// more than one .text section, and it has as many address ranges as
+// the number of .text sections. Such discontiguous address ranges are
+// stored to .debug_ranges in DWARF 2/3/4 and .debug_rnglists/.debug_addr
+// in DWARF 5.
+//
+// .debug_info section contains DWARF debug info. Although we don't need
+// to parse the whole .debug_info section to read address ranges, we
+// have to do a little bit. DWARF is complicated and often handled using
+// a library such as libdwarf. But we don't use any library because we
+// don't want to add an extra run-time dependency just for --gdb-index.
+//
+// This page explains the format of .gdb_index:
+// https://sourceware.org/gdb/onlinedocs/gdb/Index-Section-Format.html
+
+#include "mold.h"
+#include <tbb/parallel_for_each.h>
+
+namespace mold {
+
+enum DwarfKind { DWARF2_32, DWARF5_32, DWARF2_64, DWARF5_64 };
+
+template <typename E>
+struct CuHdrDwarf2_32 {
+  U32<E> size;
+  U16<E> version;
+  U32<E> abbrev_offset;
+  u8 address_size;
+};
+
+template <typename E>
+struct CuHdrDwarf5_32 {
+  U32<E> size;
+  U16<E> version;
+  u8 unit_type;
+  u8 address_size;
+  U32<E> abbrev_offset;
+};
+
+template <typename E>
+struct CuHdrDwarf2_64 {
+  U32<E> magic;
+  U64<E> size;
+  U16<E> version;
+  U64<E> abbrev_offset;
+  u8 address_size;
+};
+
+template <typename E>
+struct CuHdrDwarf5_64 {
+  U32<E> magic;
+  U64<E> size;
+  U16<E> version;
+  u8 unit_type;
+  u8 address_size;
+  U64<E> abbrev_offset;
+};
+
+template <typename E>
+struct PubnamesHdr32 {
+  U32<E> size;
+  U16<E> version;
+  U32<E> debug_info_offset;
+  U32<E> debug_info_size;
+};
+
+template <typename E>
+struct PubnamesHdr64 {
+  U32<E> magic;
+  U64<E> size;
+  U16<E> version;
+  U64<E> debug_info_offset;
+  U64<E> debug_info_size;
+};
+
+struct SectionHeader {
+  ul32 version = 7;
+  ul32 cu_list_offset = 0;
+  ul32 cu_types_offset = 0;
+  ul32 ranges_offset = 0;
+  ul32 symtab_offset = 0;
+  ul32 const_pool_offset = 0;
+};
+
+struct NameType {
+  auto operator<=>(const NameType &) const = default;
+  u64 hash;
+  u8 type;
+  std::string_view name;
+};
+
+struct MapValue {
+  u32 gdb_hash = 0;
+  Atomic<u32> count;
+  u32 name_offset = 0;
+  u32 type_offset = 0;
+};
+
+struct Compunit {
+  DwarfKind kind;
+  i64 offset;
+  i64 size;
+  std::vector<std::pair<u64, u64>> ranges;
+  std::vector<NameType> nametypes;
+  std::vector<MapValue *> entries;
+};
+
+// The hash function for .gdb_index.
+static u32 gdb_hash(std::string_view name) {
+  u32 h = 0;
+  for (u8 c : name) {
+    if ('A' <= c && c <= 'Z')
+      c = 'a' + c - 'A';
+    h = h * 67 + c - 113;
+  }
+  return h;
+}
+
+template <typename E>
+static DwarfKind get_dwarf_kind(Context<E> &ctx, u8 *p) {
+  if (*(U32<E> *)p == 0xffff'ffff) {
+    CuHdrDwarf2_64<E> &hdr = *(CuHdrDwarf2_64<E> *)p;
+    if (hdr.version > 5)
+      Fatal(ctx) << "--gdb-index: DWARF version " << hdr.version
+                 << " is not supported";
+    return (hdr.version == 5) ? DWARF5_64 : DWARF2_64;
+  }
+
+  CuHdrDwarf2_32<E> &hdr = *(CuHdrDwarf2_32<E> *)p;
+  if (hdr.version > 5)
+    Fatal(ctx) << "--gdb-index: DWARF version " << hdr.version
+               << " is not supported";
+  return (hdr.version == 5) ? DWARF5_32 : DWARF2_32;
+}
+
+template <typename E, typename CuHdr>
+u8 *find_cu_abbrev(Context<E> &ctx, u8 **p, const CuHdr &hdr) {
+  if (hdr.address_size != sizeof(Word<E>))
+    Fatal(ctx) << "--gdb-index: unsupported address size " << hdr.address_size;
+
+  if constexpr (requires { hdr.unit_type; }) {
+    switch (hdr.unit_type) {
+    case DW_UT_compile:
+    case DW_UT_partial:
+      break;
+    case DW_UT_skeleton:
+    case DW_UT_split_compile:
+      *p += 8;
+      break;
+    default:
+      Fatal(ctx) << "--gdb-index: unknown unit type: 0x"
+                 << std::hex << hdr.unit_type;
+    }
+  }
+
+  i64 abbrev_code = read_uleb(p);
+
+  // Find a .debug_abbrev record corresponding to the .debug_info record.
+  // We assume the .debug_info record at a given offset is of
+  // DW_TAG_compile_unit which describes a compunit.
+  u8 *abbrev = &ctx.debug_abbrev[0] + hdr.abbrev_offset;
+
+  for (;;) {
+    u32 code = read_uleb(&abbrev);
+    if (code == 0)
+      Fatal(ctx) << "--gdb-index: .debug_abbrev does not contain"
+                 << " a record for the first .debug_info record";
+
+    if (code == abbrev_code) {
+      // Found a record
+      u64 abbrev_tag = read_uleb(&abbrev);
+      if (abbrev_tag != DW_TAG_compile_unit && abbrev_tag != DW_TAG_skeleton_unit)
+        Fatal(ctx) << "--gdb-index: the first entry's tag is not"
+                   << " DW_TAG_compile_unit/DW_TAG_skeleton_unit but 0x"
+                   << std::hex << abbrev_tag;
+      break;
+    }
+
+    // Skip an uninteresting record
+    read_uleb(&abbrev); // tag
+    abbrev++; // has_children byte
+    for (;;) {
+      u64 name = read_uleb(&abbrev);
+      u64 form = read_uleb(&abbrev);
+      if (name == 0 && form == 0)
+        break;
+      if (form == DW_FORM_implicit_const)
+        read_uleb(&abbrev);
+    }
+  }
+
+  abbrev++; // skip has_children byte
+  return abbrev;
+}
+
+// .debug_info contains variable-length fields.
+// This function reads one scalar value from a given location.
+template <typename E, typename Offset>
+u64 read_scalar(Context<E> &ctx, u8 **p, u64 form) {
+  switch (form) {
+  case DW_FORM_flag_present:
+    return 0;
+  case DW_FORM_data1:
+  case DW_FORM_flag:
+  case DW_FORM_strx1:
+  case DW_FORM_addrx1:
+  case DW_FORM_ref1:
+    return *(*p)++;
+  case DW_FORM_data2:
+  case DW_FORM_strx2:
+  case DW_FORM_addrx2:
+  case DW_FORM_ref2: {
+    u64 val = *(U16<E> *)*p;
+    *p += 2;
+    return val;
+  }
+  case DW_FORM_strx3:
+  case DW_FORM_addrx3: {
+    u64 val = *(U24<E> *)*p;
+    *p += 3;
+    return val;
+  }
+  case DW_FORM_data4:
+  case DW_FORM_strx4:
+  case DW_FORM_addrx4:
+  case DW_FORM_ref4: {
+    u64 val = *(U32<E> *)*p;
+    *p += 4;
+    return val;
+  }
+  case DW_FORM_data8:
+  case DW_FORM_ref8: {
+    u64 val = *(U64<E> *)*p;
+    *p += 8;
+    return val;
+  }
+  case DW_FORM_strp:
+  case DW_FORM_sec_offset:
+  case DW_FORM_line_strp: {
+    u64 val = *(Offset *)*p;
+    *p += sizeof(Offset);
+    return val;
+  }
+  case DW_FORM_addr:
+  case DW_FORM_ref_addr: {
+    u64 val = *(Word<E> *)*p;
+    *p += sizeof(Word<E>);
+    return val;
+  }
+  case DW_FORM_strx:
+  case DW_FORM_addrx:
+  case DW_FORM_udata:
+  case DW_FORM_ref_udata:
+  case DW_FORM_loclistx:
+  case DW_FORM_rnglistx:
+    return read_uleb(p);
+  case DW_FORM_string:
+    *p += strlen((char *)*p) + 1;
+    return 0;
+  default:
+    Fatal(ctx) << "--gdb-index: unhandled debug info form: 0x"
+               << std::hex << form;
+  }
+}
+
+// Read a range list from .debug_ranges starting at the given offset.
+template <typename E>
+static std::vector<std::pair<u64, u64>>
+read_debug_range(Word<E> *range, u64 base) {
+  std::vector<std::pair<u64, u64>> vec;
+
+  for (i64 i = 0; range[i] || range[i + 1]; i += 2) {
+    if (range[i] + 1 == 0)
+      base = range[i + 1];
+    else
+      vec.emplace_back(range[i] + base, range[i + 1] + base);
+  }
+  return vec;
+}
+
+// Read a range list from .debug_rnglists starting at the given offset.
+template <typename E>
+static void
+read_rnglist_range(std::vector<std::pair<u64, u64>> &vec, u8 *p,
+                   Word<E> *addrx, u64 base) {
+  for (;;) {
+    switch (*p++) {
+    case DW_RLE_end_of_list:
+      return;
+    case DW_RLE_base_addressx:
+      base = addrx[read_uleb(&p)];
+      break;
+    case DW_RLE_startx_endx: {
+      u64 val1 = read_uleb(&p);
+      u64 val2 = read_uleb(&p);
+      vec.emplace_back(addrx[val1], addrx[val2]);
+      break;
+    }
+    case DW_RLE_startx_length: {
+      u64 val1 = read_uleb(&p);
+      u64 val2 = read_uleb(&p);
+      vec.emplace_back(addrx[val1], addrx[val1] + val2);
+      break;
+    }
+    case DW_RLE_offset_pair: {
+      u64 val1 = read_uleb(&p);
+      u64 val2 = read_uleb(&p);
+
+      // If the base is 0, this address range is for an eliminated
+      // section. We only emit it if it's alive.
+      if (base)
+        vec.emplace_back(base + val1, base + val2);
+      break;
+    }
+    case DW_RLE_base_address:
+      base = *(Word<E> *)p;
+      p += sizeof(Word<E>);
+      break;
+    case DW_RLE_start_end: {
+      u64 val1 = ((Word<E> *)p)[0];
+      u64 val2 = ((Word<E> *)p)[1];
+      p += sizeof(Word<E>) * 2;
+      vec.emplace_back(val1, val2);
+      break;
+    }
+    case DW_RLE_start_length: {
+      u64 val1 = *(Word<E> *)p;
+      p += sizeof(Word<E>);
+      u64 val2 = read_uleb(&p);
+      vec.emplace_back(val1, val1 + val2);
+      break;
+    }
+    }
+  }
+}
+
+// Returns a list of address ranges explained by a compunit at the
+// `offset` in an output .debug_info section.
+//
+// .debug_info contains DWARF debug info records, so this function
+// parses DWARF. If a designated compunit contains multiple ranges, the
+// ranges are read from .debug_ranges (or .debug_rnglists for DWARF5).
+// Otherwise, a range is read directly from .debug_info (or possibly
+// from .debug_addr for DWARF5).
+template <typename E, typename CuHdr>
+static std::vector<std::pair<u64, u64>>
+read_address_ranges(Context<E> &ctx, const Compunit &cu) {
+  // Read .debug_info to find the record at a given offset.
+  u8 *p = &ctx.debug_info[0] + cu.offset;
+  CuHdr &hdr = *(CuHdr *)p;
+  p += sizeof(hdr);
+
+  u8 *abbrev = find_cu_abbrev(ctx, &p, hdr);
+
+  // Now, read debug info records.
+  struct Record {
+    u64 form = 0;
+    u64 value = 0;
+  };
+
+  using Offset = decltype(hdr.size);
+
+  Record low_pc;
+  Record high_pc;
+  Record ranges;
+  u64 rnglists_base = -1;
+  Word<E> *addrx = nullptr;
+
+  // Read all interesting debug records.
+  for (;;) {
+    u64 name = read_uleb(&abbrev);
+    u64 form = read_uleb(&abbrev);
+    if (name == 0 && form == 0)
+      break;
+
+    u64 val = read_scalar<E, Offset>(ctx, &p, form);
+
+    switch (name) {
+    case DW_AT_low_pc:
+      low_pc = {form, val};
+      break;
+    case DW_AT_high_pc:
+      high_pc = {form, val};
+      break;
+    case DW_AT_rnglists_base:
+      rnglists_base = val;
+      break;
+    case DW_AT_addr_base:
+      addrx = (Word<E> *)(&ctx.debug_addr[0] + val);
+      break;
+    case DW_AT_ranges:
+      ranges = {form, val};
+      break;
+    }
+  }
+
+  // Handle non-contiguous address ranges.
+  if (ranges.form) {
+    if (hdr.version <= 4) {
+      Word<E> *p = (Word<E> *)(&ctx.debug_ranges[0] + ranges.value);
+      return read_debug_range<E>(p, low_pc.value);
+    }
+
+    assert(hdr.version == 5);
+
+    std::vector<std::pair<u64, u64>> vec;
+    u8 *buf = &ctx.debug_rnglists[0];
+
+    if (ranges.form == DW_FORM_sec_offset) {
+      read_rnglist_range<E>(vec, buf + ranges.value, addrx, low_pc.value);
+    } else {
+      if (rnglists_base == -1)
+        Fatal(ctx) << "--gdb-index: missing DW_AT_rnglists_base";
+
+      u8 *base = buf + rnglists_base;
+      Offset *offsets = (Offset *)base;
+      read_rnglist_range<E>(vec, base + offsets[ranges.value], addrx, low_pc.value);
+    }
+    return vec;
+  }
+
+  // Handle a contiguous address range.
+  if (low_pc.form && high_pc.form) {
+    u64 lo;
+
+    switch (low_pc.form) {
+    case DW_FORM_addr:
+      lo = low_pc.value;
+      break;
+    case DW_FORM_addrx:
+    case DW_FORM_addrx1:
+    case DW_FORM_addrx2:
+    case DW_FORM_addrx4:
+      lo = addrx[low_pc.value];
+      break;
+    default:
+      Fatal(ctx) << "--gdb-index: unhandled form for DW_AT_low_pc: 0x"
+                 << std::hex << high_pc.form;
+    }
+
+    switch (high_pc.form) {
+    case DW_FORM_addr:
+      return {{lo, high_pc.value}};
+    case DW_FORM_addrx:
+    case DW_FORM_addrx1:
+    case DW_FORM_addrx2:
+    case DW_FORM_addrx4:
+      return {{lo, addrx[high_pc.value]}};
+    case DW_FORM_udata:
+    case DW_FORM_data1:
+    case DW_FORM_data2:
+    case DW_FORM_data4:
+    case DW_FORM_data8:
+      return {{lo, lo + high_pc.value}};
+    default:
+      Fatal(ctx) << "--gdb-index: unhandled form for DW_AT_high_pc: 0x"
+                 << std::hex << high_pc.form;
+    }
+  }
+
+  return {};
+}
+
+template <typename E, typename PubnamesHdr>
+static i64 read_pubnames_cu(Context<E> &ctx, const PubnamesHdr &hdr,
+                            std::vector<Compunit> &cus, ObjectFile<E> &file) {
+  using Offset = decltype(hdr.size);
+
+  auto get_cu = [&](i64 offset) {
+    for (i64 i = 0; i < cus.size(); i++)
+      if (cus[i].offset == offset)
+        return &cus[i];
+    Fatal(ctx) << file << ": corrupted debug_info_offset";
+  };
+
+  Compunit *cu = get_cu(file.debug_info->offset + hdr.debug_info_offset);
+  i64 size = hdr.size + offsetof(PubnamesHdr, size) + sizeof(hdr.size);
+  u8 *p = (u8 *)&hdr + sizeof(hdr);
+  u8 *end = (u8 *)&hdr + size;
+
+  while (p < end) {
+    if (*(Offset *)p == 0)
+      break;
+    p += sizeof(Offset);
+
+    u8 type = *p++;
+    std::string_view name = (char *)p;
+    p += name.size() + 1;
+    cu->nametypes.push_back(NameType{hash_string(name), type, name});
+  }
+
+  return size;
+}
+
+// Parses .debug_gnu_pubnames and .debug_gnu_pubtypes. These sections
+// start with a 14 bytes header followed by (4-byte offset, 1-byte type,
+// null-terminated string) tuples.
+//
+// The 4-byte offset is an offset into .debug_info that contains details
+// about the name. The 1-byte type is a type of the corresponding name
+// (e.g. function, variable or datatype). The string is a name of a
+// function, a variable or a type.
+template <typename E>
+static void read_pubnames(Context<E> &ctx, std::vector<Compunit> &cus,
+                          ObjectFile<E> &file) {
+  for (InputSection<E> *isec : { file.debug_pubnames, file.debug_pubtypes }) {
+    if (!isec)
+      continue;
+
+    isec->uncompress(ctx);
+    if (isec->contents.empty())
+      continue;
+
+    u8 *p = (u8*)&isec->contents[0];
+    u8 *end = p + isec->contents.size();
+
+    while (p < end) {
+      if (*(U32<E> *)p == 0xffff'ffff)
+        p += read_pubnames_cu(ctx, *(PubnamesHdr64<E> *)p, cus, file);
+      else
+        p += read_pubnames_cu(ctx, *(PubnamesHdr32<E> *)p, cus, file);
+    }
+  };
+}
+
+template <typename E>
+static std::vector<Compunit> read_compunits(Context<E> &ctx) {
+  std::vector<Compunit> cus;
+
+  // Read compunits from the output .debug_info section.
+  u8 *begin = &ctx.debug_info[0];
+  u8 *end = begin + ctx.debug_info.size();
+
+  for (u8 *p = begin; p < end;) {
+    DwarfKind kind = get_dwarf_kind(ctx, p);
+    i64 size;
+    if (kind == DWARF2_32 || kind == DWARF5_32)
+      size = ((CuHdrDwarf2_32<E> *)p)->size + 4;
+    else
+      size = ((CuHdrDwarf2_64<E> *)p)->size + 12;
+
+    cus.push_back(Compunit{kind, p - begin, size});
+    p += size;
+  }
+
+  // Read address ranges for each compunit.
+  tbb::parallel_for_each(cus, [&](Compunit &cu) {
+    switch (cu.kind) {
+    case DWARF2_32:
+      cu.ranges = read_address_ranges<E, CuHdrDwarf2_32<E>>(ctx, cu);
+      break;
+    case DWARF5_32:
+      cu.ranges = read_address_ranges<E, CuHdrDwarf5_32<E>>(ctx, cu);
+      break;
+    case DWARF2_64:
+      cu.ranges = read_address_ranges<E, CuHdrDwarf2_64<E>>(ctx, cu);
+      break;
+    case DWARF5_64:
+      cu.ranges = read_address_ranges<E, CuHdrDwarf5_64<E>>(ctx, cu);
+      break;
+    }
+
+    // Remove empty ranges
+    std::erase_if(cu.ranges, [](std::pair<u64, u64> p) {
+      return p.first == 0 || p.first == p.second;
+    });
+  });
+
+  // Read symbols from .debug_gnu_pubnames and .debug_gnu_pubtypes.
+  tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
+    read_pubnames(ctx, cus, *file);
+  });
+
+  // Uniquify elements because GCC 11 seems to emit one record for each
+  // comdat group which results in having a lot of duplicate records.
+  tbb::parallel_for_each(cus, [](Compunit &cu) {
+    ranges::stable_sort(cu.nametypes);
+    remove_duplicates(cu.nametypes);
+  });
+
+  return cus;
+}
+
+template <typename E>
+std::span<u8> get_buffer(Context<E> &ctx, Chunk<E> *chunk) {
+  if (chunk->is_compressed) {
+    CompressedSection<E> &sec = *(CompressedSection<E> *)chunk;
+    return {sec.uncompressed_data.get(), (size_t)sec.chdr.ch_size};
+  }
+  return {ctx.buf + chunk->shdr.sh_offset, (size_t)chunk->shdr.sh_size};
+}
+
+template <typename E>
+void write_gdb_index(Context<E> &ctx) {
+  Timer t(ctx, "write_gdb_index");
+
+  // Find debug info sections
+  for (Chunk<E> *chunk : ctx.chunks) {
+    std::string_view name = chunk->name;
+    if (name == ".debug_info")
+      ctx.debug_info = get_buffer(ctx, chunk);
+    if (name == ".debug_abbrev")
+      ctx.debug_abbrev = get_buffer(ctx, chunk);
+    if (name == ".debug_ranges")
+      ctx.debug_ranges = get_buffer(ctx, chunk);
+    if (name == ".debug_addr")
+      ctx.debug_addr = get_buffer(ctx, chunk);
+    if (name == ".debug_rnglists")
+      ctx.debug_rnglists = get_buffer(ctx, chunk);
+  }
+
+  if (ctx.debug_info.empty())
+    return;
+
+  // Read debug info
+  std::vector<Compunit> cus = read_compunits(ctx);
+
+  // Uniquify symbols
+  HyperLogLog estimator;
+
+  tbb::parallel_for_each(cus, [&](Compunit &cu) {
+    HyperLogLog e;
+    for (NameType &nt : cu.nametypes)
+      e.insert(nt.hash);
+    estimator.merge(e);
+  });
+
+  ConcurrentMap<MapValue> map(estimator.get_cardinality() * 3 / 2);
+
+  tbb::parallel_for_each(cus, [&](Compunit &cu) {
+    cu.entries.reserve(cu.nametypes.size());
+    for (NameType &nt : cu.nametypes) {
+      MapValue *ent;
+      bool inserted;
+      std::tie(ent, inserted) = map.insert(nt.name, nt.hash,
+                                           MapValue{gdb_hash(nt.name)});
+      ent->count++;
+      cu.entries.push_back(ent);
+    }
+  });
+
+  // Sort symbols for build reproducibility
+  using Entry = typename decltype(map)::Entry;
+  std::vector<Entry *> entries = map.get_sorted_entries_all();
+
+  // Compute sizes of each components
+  SectionHeader hdr;
+  hdr.cu_list_offset = sizeof(hdr);
+  hdr.cu_types_offset = hdr.cu_list_offset + cus.size() * 16;
+  hdr.ranges_offset = hdr.cu_types_offset;
+
+  hdr.symtab_offset = hdr.ranges_offset;
+  for (Compunit &cu : cus)
+    hdr.symtab_offset += cu.ranges.size() * 20;
+
+  i64 ht_size = bit_ceil(entries.size() * 5 / 4 + 1);
+  hdr.const_pool_offset = hdr.symtab_offset + ht_size * 8;
+
+  i64 offset = 0;
+  for (Entry *ent : entries) {
+    ent->value.type_offset = offset;
+    offset += ent->value.count * 4 + 4;
+  }
+
+  for (Entry *ent : entries) {
+    ent->value.name_offset = offset;
+    offset += ent->keylen + 1;
+  }
+
+  i64 bufsize = hdr.const_pool_offset + offset;
+
+  // Allocate an output buffer. We use malloc instead of vector to
+  // avoid zero-initializing the entire buffer.
+  ctx.output_file->buf2 = (u8 *)malloc(bufsize);
+  ctx.output_file->buf2_size = bufsize;
+  u8 *buf = ctx.output_file->buf2;
+
+  // Write a section header
+  memcpy(buf, &hdr, sizeof(hdr));
+
+  // Write a CU list
+  u8 *p = buf + sizeof(hdr);
+
+  for (Compunit &cu : cus) {
+    *(ul64 *)p = cu.offset;
+    *(ul64 *)(p + 8) = cu.size;
+    p += 16;
+  }
+
+  // Write address areas
+  std::vector<i64> range_offsets(cus.size());
+  for (i64 i = 1; i < cus.size(); i++)
+    range_offsets[i] = range_offsets[i - 1] + cus[i - 1].ranges.size() * 20;
+
+  tbb::parallel_for_each(cus, [&](Compunit &cu) {
+    i64 i = &cu - cus.data();
+    u8 *p = buf + hdr.ranges_offset + range_offsets[i];
+    for (std::pair<u64, u64> range : cu.ranges) {
+      *(ul64 *)p = range.first;
+      *(ul64 *)(p + 8) = range.second;
+      *(ul32 *)(p + 16) = i;
+      p += 20;
+    }
+  });
+
+  // Write a symbol table
+  u32 mask = ht_size - 1;
+  ul32 *ht = (ul32 *)(buf + hdr.symtab_offset);
+  memset(ht, 0, ht_size * 8);
+
+  for (Entry *ent : entries) {
+    u32 hash = ent->value.gdb_hash;
+    u32 step = ((hash * 17) & mask) | 1;
+    u32 j = hash & mask;
+
+    while (ht[j * 2] || ht[j * 2 + 1])
+      j = (j + step) & mask;
+
+    ht[j * 2] = ent->value.name_offset;
+    ht[j * 2 + 1] = ent->value.type_offset;
+  }
+
+  // Write types. Use MapValue::count as an atomic slot counter.
+  u8 *base = buf + hdr.const_pool_offset;
+
+  for (Entry *ent : entries)
+    ent->value.count = 0;
+
+  tbb::parallel_for_each(cus, [&](Compunit &cu) {
+    i64 i = &cu - cus.data();
+    for (i64 j = 0; j < cu.nametypes.size(); j++) {
+      MapValue *ent = cu.entries[j];
+      ul32 *p = (ul32 *)(base + ent->type_offset);
+      i64 idx = ++ent->count;
+      p[idx] = (cu.nametypes[j].type << 24) | i;
+    }
+  });
+
+  // Write the final counts into the buffer.
+  tbb::parallel_for_each(entries, [&](Entry *ent) {
+    ul32 *p = (ul32 *)(base + ent->value.type_offset);
+    p[0] = ent->value.count;
+    // Sort entries for deterministic output
+    std::sort(p + 1, p + 1 + ent->value.count);
+  });
+
+  // Write names
+  tbb::parallel_for_each(entries, [&](Entry *ent) {
+    u8 *dst = buf + hdr.const_pool_offset + ent->value.name_offset;
+    memcpy(dst, ent->key, ent->keylen);
+    dst[ent->keylen] = '\0';
+  });
+
+  // Update the section size and rewrite the section header
+  if (ctx.shdr) {
+    ctx.gdb_index->shdr.sh_size = bufsize;
+    ctx.shdr->copy_buf(ctx);
+  }
+}
+
+using E = MOLD_TARGET;
+
+template void write_gdb_index(Context<E> &);
+
+} // namespace mold

src/icf.cc

@@ -65,10 +65,11 @@
 // conditions.
 
 #include "mold.h"
-#include "../common/sha.h"
+#include "../lib/siphash.h"
 
 #include <array>
 #include <cstdio>
+#include <fstream>
 #include <tbb/concurrent_unordered_map.h>
 #include <tbb/concurrent_vector.h>
 #include <tbb/enumerable_thread_specific.h>
@@ -78,34 +79,43 @@
 
 static constexpr int64_t HASH_SIZE = 16;
 
-typedef std::array<uint8_t, HASH_SIZE> Digest;
+using Digest = std::array<uint8_t, HASH_SIZE>;
 
 namespace std {
-template<> struct hash<Digest> {
+template <> struct hash<Digest> {
   size_t operator()(const Digest &k) const {
-    return *(int64_t *)&k[0];
+    static_assert(sizeof(size_t) <= HASH_SIZE);
+    size_t val;
+    memcpy(&val, k.data(), sizeof(size_t));
+    return val;
   }
 };
 }
 
-namespace mold::elf {
+namespace mold {
+
+static u8 hmac_key[16];
 
 template <typename E>
 static void uniquify_cies(Context<E> &ctx) {
   Timer t(ctx, "uniquify_cies");
   std::vector<CieRecord<E> *> cies;
 
+  auto find = [&](CieRecord<E> &cie) -> i64 {
+    for (i64 i = 0; i < cies.size(); i++)
+      if (cie_equals(cie, *cies[i]))
+        return i;
+    return -1;
+  };
+
   for (ObjectFile<E> *file : ctx.objs) {
     for (CieRecord<E> &cie : file->cies) {
-      for (i64 i = 0; i < cies.size(); i++) {
-        if (cie.equals(*cies[i])) {
-          cie.icf_idx = i;
-          goto found;
-        }
+      if (i64 idx = find(cie); idx != -1) {
+        cie.icf_idx = idx;
+      } else {
+        cie.icf_idx = cies.size();
+        cies.push_back(&cie);
       }
-      cie.icf_idx = cies.size();
-      cies.push_back(&cie);
-    found:;
     }
   }
 }
@@ -113,32 +123,26 @@ static void uniquify_cies(Context<E> &ctx) {
 template <typename E>
 static bool is_eligible(Context<E> &ctx, InputSection<E> &isec) {
   const ElfShdr<E> &shdr = isec.shdr();
-  std::string_view name = isec.name();
 
-  bool is_alloc = (shdr.sh_flags & SHF_ALLOC);
-  bool is_exec = (shdr.sh_flags & SHF_EXECINSTR) ||
-                 ctx.arg.ignore_data_address_equality;
-  bool is_relro = (name == ".data.rel.ro" ||
-                   name.starts_with(".data.rel.ro."));
-  bool is_readonly = !(shdr.sh_flags & SHF_WRITE) || is_relro;
-  bool is_bss = (shdr.sh_type == SHT_NOBITS);
-  bool is_empty = (shdr.sh_size == 0);
-  bool is_init = (shdr.sh_type == SHT_INIT_ARRAY || name == ".init");
-  bool is_fini = (shdr.sh_type == SHT_FINI_ARRAY || name == ".fini");
-  bool is_enumerable = is_c_identifier(name);
-  bool is_addr_taken = !ctx.arg.icf_all && isec.address_significant;
+  if (shdr.sh_size == 0 || !(shdr.sh_flags & SHF_ALLOC) ||
+      shdr.sh_type == SHT_NOBITS || is_c_identifier(isec.name))
+    return false;
 
-  return is_alloc && is_exec && is_readonly && !is_bss && !is_empty &&
-         !is_init && !is_fini && !is_enumerable && !is_addr_taken;
-}
+  if (shdr.sh_flags & SHF_EXECINSTR)
+    return (ctx.arg.icf_all || !isec.address_taken) &&
+           isec.name != ".init" && isec.name != ".fini";
 
-static Digest digest_final(SHA256Hash &sha) {
-  u8 buf[SHA256_SIZE];
-  sha.finish(buf);
+  // .gcc_except_table contains a compiler-generated table. Pointer
+  // equality for the section is not significant because only the C++
+  // exception handling code will use the table at runtime.
+  if (isec.name == ".gcc_except_table" ||
+      isec.name.starts_with(".gcc_except_table."))
+    return true;
 
-  Digest digest;
-  memcpy(digest.data(), buf, HASH_SIZE);
-  return digest;
+  bool is_readonly = !(shdr.sh_flags & SHF_WRITE);
+  bool is_relro = isec.name.starts_with(".data.rel.ro");
+  return (ctx.arg.ignore_data_address_equality || !isec.address_taken) &&
+         (is_readonly || is_relro);
 }
 
 template <typename E>
@@ -195,7 +199,7 @@ static void merge_leaf_nodes(Context<E> &ctx) {
   static Counter non_eligible("icf_non_eligibles");
   static Counter leaf("icf_leaf_nodes");
 
-  tbb::concurrent_unordered_map<InputSection<E> *, InputSection<E> *,
+  tbb::concurrent_unordered_map<InputSection<E> *, Atomic<InputSection<E> *>,
                                 LeafHasher<E>, LeafEq<E>> map;
 
   tbb::parallel_for((i64)0, (i64)ctx.objs.size(), [&](i64 i) {
@@ -212,8 +216,11 @@ static void merge_leaf_nodes(Context<E> &ctx) {
         leaf++;
         isec->icf_leaf = true;
         auto [it, inserted] = map.insert({isec.get(), isec.get()});
-        if (!inserted && isec->get_priority() < it->second->get_priority())
-          it->second = isec.get();
+        if (!inserted) {
+          InputSection<E> *isec2 = it->second.load();
+          while (isec->get_priority() < isec2->get_priority() &&
+                 !it->second.compare_exchange_strong(isec2, isec.get()));
+        }
       } else {
         eligible++;
         isec->icf_eligible = true;
@@ -234,21 +241,21 @@ static void merge_leaf_nodes(Context<E> &ctx) {
 
 template <typename E>
 static Digest compute_digest(Context<E> &ctx, InputSection<E> &isec) {
-  SHA256Hash sha;
+  SipHash13_128 hasher(hmac_key);
 
   auto hash = [&](auto val) {
-    sha.update((u8 *)&val, sizeof(val));
+    hasher.update((u8 *)&val, sizeof(val));
   };
 
   auto hash_string = [&](std::string_view str) {
     hash(str.size());
-    sha.update((u8 *)str.data(), str.size());
+    hasher.update((u8 *)str.data(), str.size());
   };
 
   auto hash_symbol = [&](Symbol<E> &sym) {
     InputSection<E> *isec = sym.get_input_section();
 
-    if (!sym.file) {
+    if (!sym.file || sym.is_imported) {
       hash('1');
       hash((u64)&sym);
     } else if (SectionFragment<E> *frag = sym.get_frag()) {
@@ -298,7 +305,9 @@ static Digest compute_digest(Context<E> &ctx, InputSection<E> &isec) {
     hash_symbol(*isec.file.symbols[rel.r_sym]);
   }
 
-  return digest_final(sha);
+  Digest digest;
+  hasher.finish(digest.data());
+  return digest;
 }
 
 template <typename E>
@@ -399,7 +408,7 @@ static void gather_edges(Context<E> &ctx,
 template <typename E>
 static i64 propagate(std::span<std::vector<Digest>> digests,
                      std::span<u32> edges, std::span<u32> edge_indices,
-                     bool &slot, BitVector &converged,
+                     bool &slot, std::span<u8> converged,
                      tbb::affinity_partitioner &ap) {
   static Counter round("icf_round");
   round++;
@@ -408,24 +417,24 @@ static i64 propagate(std::span<std::vector<Digest>> digests,
   tbb::enumerable_thread_specific<i64> changed;
 
   tbb::parallel_for((i64)0, num_digests, [&](i64 i) {
-    if (converged.get(i))
+    if (converged[i])
       return;
 
-    SHA256Hash sha;
-    sha.update(digests[2][i].data(), HASH_SIZE);
+    SipHash13_128 hasher(hmac_key);
+    hasher.update(digests[2][i].data(), HASH_SIZE);
 
     i64 begin = edge_indices[i];
     i64 end = (i + 1 == num_digests) ? edges.size() : edge_indices[i + 1];
 
     for (i64 j : edges.subspan(begin, end - begin))
-      sha.update(digests[slot][j].data(), HASH_SIZE);
+      hasher.update(digests[slot][j].data(), HASH_SIZE);
 
-    digests[!slot][i] = digest_final(sha);
+    hasher.finish(digests[!slot][i].data());
 
     if (digests[slot][i] == digests[!slot][i]) {
       // This node has converged. Skip further iterations as it will
       // yield the same hash.
-      converged.set(i);
+      converged[i] = true;
     } else {
       changed.local()++;
     }
@@ -466,28 +475,36 @@ static void print_icf_sections(Context<E> &ctx) {
   });
 
   tbb::parallel_sort(leaders.begin(), leaders.end(),
-                     [&](InputSection<E> *a, InputSection<E> *b) {
+                     [](InputSection<E> *a, InputSection<E> *b) {
                        return a->get_priority() < b->get_priority();
                      });
 
+  std::ostream *out = &std::cout;
+  std::ofstream file;
+
+  std::string &path = ctx.arg.print_icf_sections;
+  if (path != "-") {
+    file.open(path);
+    if (file.fail())
+      Fatal(ctx) << "--print-icf-sections: cannot open " << path << ": "
+                 << errno_string();
+    out = &file;
+  }
+
   i64 saved_bytes = 0;
 
   for (InputSection<E> *leader : leaders) {
     auto [begin, end] = map.equal_range(leader);
-    if (begin == end)
-      continue;
-
-    SyncOut(ctx) << "selected section " << *leader;
-
-    i64 n = 0;
-    for (auto it = begin; it != end; it++) {
-      SyncOut(ctx) << "  removing identical section " << *it->second;
-      n++;
+    if (begin != end) {
+      *out << "selected section " << *leader << '\n';
+      for (auto it = begin; it != end; it++) {
+        *out << "  removing identical section " << *it->second << '\n';
+        saved_bytes += leader->contents.size();
+      }
     }
-    saved_bytes += leader->contents.size() * n;
   }
 
-  SyncOut(ctx) << "ICF saved " << saved_bytes << " bytes";
+  *out << "ICF saved " << saved_bytes << " bytes\n";
 }
 
 template <typename E>
@@ -496,6 +513,8 @@ void icf_sections(Context<E> &ctx) {
   if (ctx.objs.empty())
     return;
 
+  get_random_bytes(hmac_key, sizeof(hmac_key));
+
   uniquify_cies(ctx);
   merge_leaf_nodes(ctx);
 
@@ -520,7 +539,7 @@ void icf_sections(Context<E> &ctx) {
   std::vector<u32> edge_indices;
   gather_edges<E>(ctx, sections, edges, edge_indices);
 
-  BitVector converged(digests[0].size());
+  std::vector<u8> converged(digests[0].size());
   bool slot = 0;
 
   // Execute the propagation rounds until convergence is obtained.
@@ -563,18 +582,23 @@ void icf_sections(Context<E> &ctx) {
     }
   }
 
-  // Group sections by SHA digest.
+  // Group sections by hash values.
   {
     Timer t(ctx, "group");
 
-    auto *map = new tbb::concurrent_unordered_map<Digest, InputSection<E> *>;
+    auto *map =
+      new tbb::concurrent_unordered_map<Digest, Atomic<InputSection<E> *>>;
+
     std::span<Digest> digest = digests[slot];
 
     tbb::parallel_for((i64)0, (i64)sections.size(), [&](i64 i) {
       InputSection<E> *isec = sections[i];
       auto [it, inserted] = map->insert({digest[i], isec});
-      if (!inserted && isec->get_priority() < it->second->get_priority())
-        it->second = isec;
+      if (!inserted) {
+        InputSection<E> *isec2 = it->second.load();
+        while (isec->get_priority() < isec2->get_priority() &&
+               !it->second.compare_exchange_strong(isec2, isec));
+      }
     });
 
     tbb::parallel_for((i64)0, (i64)sections.size(), [&](i64 i) {
@@ -587,9 +611,21 @@ void icf_sections(Context<E> &ctx) {
     ctx.on_exit.push_back([=] { delete map; });
   }
 
-  if (ctx.arg.print_icf_sections)
+  if (!ctx.arg.print_icf_sections.empty())
     print_icf_sections(ctx);
 
+  // Update alignment of leaders.
+  {
+    Timer t(ctx, "update_alignment");
+    tbb::parallel_for_each(ctx.objs, [](ObjectFile<E> *file) {
+      for (std::unique_ptr<InputSection<E>> &isec : file->sections) {
+        if (isec && isec->is_alive && isec->leader && isec->leader != isec.get()) {
+          update_maximum(isec->leader->p2align, isec->p2align);
+        }
+      }
+    });
+  }
+
   // Eliminate duplicate sections.
   // Symbols pointing to eliminated sections will be redirected on the fly when
   // exporting to the symtab.
@@ -598,7 +634,7 @@ void icf_sections(Context<E> &ctx) {
     static Counter eliminated("icf_eliminated");
     tbb::parallel_for_each(ctx.objs, [](ObjectFile<E> *file) {
       for (std::unique_ptr<InputSection<E>> &isec : file->sections) {
-        if (isec && isec->is_alive && isec->is_killed_by_icf()) {
+        if (isec && isec->is_alive && isec->icf_removed()) {
           isec->kill();
           eliminated++;
         }
@@ -611,4 +647,4 @@ using E = MOLD_TARGET;
 
 template void icf_sections(Context<E> &ctx);
 
-} // namespace mold::elf
+} // namespace mold

src/input-sections.cc

@@ -0,0 +1,458 @@
+#include "mold.h"
+
+#include <zlib.h>
+#include <zstd.h>
+
+namespace mold {
+
+static i64 to_p2align(u64 alignment) {
+  if (alignment == 0)
+    return 0;
+  return std::countr_zero(alignment);
+}
+
+template <typename E>
+bool cie_equals(const CieRecord<E> &a, const CieRecord<E> &b) {
+  if (a.get_contents() != b.get_contents())
+    return false;
+
+  std::span<const ElfRel<E>> x = a.get_rels();
+  std::span<const ElfRel<E>> y = b.get_rels();
+  if (x.size() != y.size())
+    return false;
+
+  for (i64 i = 0; i < x.size(); i++)
+    if (x[i].r_offset - a.input_offset != y[i].r_offset - b.input_offset ||
+        x[i].r_type != y[i].r_type ||
+        a.file.symbols[x[i].r_sym] != b.file.symbols[y[i].r_sym] ||
+        get_addend(a.input_section, x[i]) != get_addend(b.input_section, y[i]))
+      return false;
+  return true;
+}
+
+template <typename E>
+InputSection<E>::InputSection(Context<E> &ctx, ObjectFile<E> &file, i64 shndx)
+  : file(file), shndx(shndx) {
+  if (shndx < file.elf_sections.size()) {
+    name = file.shstrtab.data() + file.elf_sections[shndx].sh_name;
+    contents = {(char *)file.mf->data + shdr().sh_offset, (size_t)shdr().sh_size};
+  } else {
+    name = (shdr().sh_flags & SHF_TLS) ? ".tls_common" : ".common";
+  }
+
+  if (shdr().sh_flags & SHF_COMPRESSED) {
+    ElfChdr<E> &chdr = *(ElfChdr<E> *)&contents[0];
+    sh_size = chdr.ch_size;
+    p2align = to_p2align(chdr.ch_addralign);
+  } else {
+    sh_size = shdr().sh_size;
+    p2align = to_p2align(shdr().sh_addralign);
+  }
+
+  // Sections may have been compressed. We usually uncompress them
+  // directly into the mmap'ed output file, but we want to uncompress
+  // early for REL-type ELF types to read relocation addends from
+  // section contents. For RELA-type, we don't need to do this because
+  // addends are in relocations.
+  //
+  // SH-4 stores addends to sections despite being RELA, which is a
+  // special (and buggy) case.
+  if constexpr (!E::is_rela || is_sh4<E>)
+    uncompress(ctx);
+}
+
+template <typename E>
+void InputSection<E>::uncompress(Context<E> &ctx) {
+  if (!(shdr().sh_flags & SHF_COMPRESSED) || uncompressed)
+    return;
+
+  u8 *buf = new u8[sh_size];
+  copy_contents_to(ctx, buf, sh_size);
+  contents = std::string_view((char *)buf, sh_size);
+  ctx.string_pool.emplace_back(buf);
+  uncompressed = true;
+}
+
+template <typename E>
+void InputSection<E>::copy_contents_to(Context<E> &ctx, u8 *buf, i64 sz) {
+  if (!(shdr().sh_flags & SHF_COMPRESSED) || uncompressed) {
+    memcpy(buf, contents.data(), sz);
+    return;
+  }
+
+  if (contents.size() < sizeof(ElfChdr<E>))
+    Fatal(ctx) << *this << ": corrupted compressed section";
+
+  ElfChdr<E> &hdr = *(ElfChdr<E> *)&contents[0];
+  std::string_view data = contents.substr(sizeof(ElfChdr<E>));
+
+  switch (hdr.ch_type) {
+  case ELFCOMPRESS_ZLIB: {
+    z_stream s = {};
+    inflateInit(&s);
+    s.next_in = (u8 *)data.data();
+    s.avail_in = data.size();
+    s.next_out = buf;
+    s.avail_out = sz;
+
+    int r;
+    while (s.total_out < sz && (r = inflate(&s, Z_NO_FLUSH)) == Z_OK);
+    if (s.total_out < sz && r != Z_STREAM_END)
+      Fatal(ctx) << *this << ": uncompress failed: " << s.msg;
+    inflateEnd(&s);
+    msan_unpoison(buf, sz);
+    break;
+  }
+  case ELFCOMPRESS_ZSTD: {
+    ZSTD_DCtx *dctx = ZSTD_createDCtx();
+    ZSTD_inBuffer in = { data.data(), data.size() };
+    ZSTD_outBuffer out = { buf, (size_t)sz };
+
+    while (out.pos < out.size) {
+      size_t r = ZSTD_decompressStream(dctx, &out, &in);
+      if (ZSTD_isError(r))
+        Fatal(ctx) << *this << ": uncompress failed: " << ZSTD_getErrorName(r);
+      if (r == 0 && out.pos < out.size)
+        Fatal(ctx) << *this << ": uncompress failed: premature end of input";
+    }
+    ZSTD_freeDCtx(dctx);
+    msan_unpoison(buf, sz);
+    break;
+  }
+  default:
+    Fatal(ctx) << *this << ": unsupported compression type: 0x"
+               << std::hex << hdr.ch_type;
+  }
+}
+
+// wingdi.h defines ERROR as a macro, so undefine it before use
+#undef ERROR
+
+typedef enum : u8 { NONE, ERROR, COPYREL, PLT, CPLT } Action;
+
+template <typename E>
+static void do_action(Context<E> &ctx, Action action, InputSection<E> &isec,
+                      Symbol<E> &sym, const ElfRel<E> &rel) {
+  switch (action) {
+  case NONE:
+    break;
+  case ERROR:
+    Error(ctx) << isec << ": " << rel << " relocation at offset 0x"
+               << std::hex << rel.r_offset << " against symbol `"
+               << sym << "' can not be used; recompile with -fPIC";
+    break;
+  case COPYREL:
+    sym.flags |= NEEDS_COPYREL;
+    break;
+  case PLT:
+    // Create a PLT entry
+    sym.flags |= NEEDS_PLT;
+    break;
+  case CPLT:
+    // Create a canonical PLT entry
+    sym.flags |= NEEDS_CPLT;
+    break;
+  }
+}
+
+template <typename E>
+static inline i64 get_output_type(Context<E> &ctx) {
+  if (ctx.arg.shared)
+    return 0;
+  if (ctx.arg.pie)
+    return 1;
+  return 2;
+}
+
+template <typename E>
+static inline i64 get_sym_type(Symbol<E> &sym) {
+  if (sym.is_absolute())
+    return 0;
+  if (!sym.is_imported)
+    return 1;
+  if (sym.get_type() != STT_FUNC)
+    return 2;
+  return 3;
+}
+
+template <typename E>
+void InputSection<E>::scan_pcrel(Context<E> &ctx, Symbol<E> &sym,
+                                 const ElfRel<E> &rel) {
+  // This is for PC-relative relocations (e.g. R_X86_64_PC32).
+  // We cannot promote them to dynamic relocations because the dynamic
+  // linker generally does not support PC-relative relocations.
+  static Action table[][4] = {
+    // Absolute  Local    Imported data  Imported code
+    {  ERROR,    NONE,    ERROR,         PLT    },  // Shared object
+    {  ERROR,    NONE,    COPYREL,       CPLT   },  // Position-independent exec
+    {  NONE,     NONE,    COPYREL,       CPLT   },  // Position-dependent exec
+  };
+
+  Action action = table[get_output_type(ctx)][get_sym_type(sym)];
+  do_action(ctx, action, *this, sym, rel);
+}
+
+template <typename E>
+void InputSection<E>::scan_absrel(Context<E> &ctx, Symbol<E> &sym,
+                                  const ElfRel<E> &rel) {
+  // This is a decision table for absolute relocations that is smaller
+  // than the pointer size (e.g. R_X86_64_32). Since the dynamic linker
+  // generally does not support dynamic relocations smaller than the
+  // pointer size, we need to report an error if a relocation cannot be
+  // resolved at link-time.
+  static Action table[][4] = {
+    // Absolute  Local    Imported data  Imported code
+    {  NONE,     ERROR,   ERROR,         ERROR },  // Shared object
+    {  NONE,     ERROR,   ERROR,         ERROR },  // Position-independent exec
+    {  NONE,     NONE,    COPYREL,       CPLT  },  // Position-dependent exec
+  };
+
+  Action action = table[get_output_type(ctx)][get_sym_type(sym)];
+  do_action(ctx, action, *this, sym, rel);
+}
+
+template <typename E>
+void InputSection<E>::scan_tlsdesc(Context<E> &ctx, Symbol<E> &sym) {
+  if (ctx.arg.static_ || (ctx.arg.relax && sym.is_tprel_linktime_const(ctx))) {
+    // Relax TLSDESC to Local Exec. In this case, we directly materialize
+    // a TP-relative offset, so no dynamic relocation is needed.
+    //
+    // TLSDESC relocs must always be relaxed for statically-linked
+    // executables even if -no-relax is given. It is because a
+    // statically-linked executable doesn't contain a trampoline
+    // function needed for TLSDESC.
+  } else if (ctx.arg.relax && sym.is_tprel_runtime_const(ctx)) {
+    // In this condition, TP-relative offset of a thread-local variable
+    // is known at process startup time, so we can relax TLSDESC to the
+    // code that reads the TP-relative offset from GOT and add TP to it.
+    sym.flags |= NEEDS_GOTTP;
+  } else {
+    // If no relaxation is doable, we simply create a TLSDESC dynamic
+    // relocation.
+    sym.flags |= NEEDS_TLSDESC;
+  }
+}
+
+template <typename E>
+void InputSection<E>::check_tlsle(Context<E> &ctx, Symbol<E> &sym,
+                                  const ElfRel<E> &rel) {
+  if (ctx.arg.shared)
+    Error(ctx) << *this << ": relocation " << rel << " against `" << sym
+               << "` can not be used when making a shared object;"
+               << " recompile with -fPIC";
+}
+
+template <typename E>
+void InputSection<E>::write_to(Context<E> &ctx, u8 *buf) {
+  if (shdr().sh_type == SHT_NOBITS || sh_size == 0)
+    return;
+
+  // Copy data. In RISC-V and LoongArch object files, sections are not
+  // atomic unit of copying because of relaxation. That is, some
+  // relocations are allowed to remove bytes from the middle of a
+  // section and shrink the overall size of it.
+  if constexpr (is_riscv<E> || is_loongarch<E>) {
+    std::span<RelocDelta> deltas = extra.r_deltas;
+
+    if (deltas.empty()) {
+      // If a section is not relaxed, we can copy it as a one big chunk.
+      copy_contents_to(ctx, buf, sh_size);
+    } else {
+      // A relaxed section is copied piece-wise.
+      memcpy(buf, contents.data(), deltas[0].offset);
+
+      for (i64 i = 0; i < deltas.size(); i++) {
+        i64 offset = deltas[i].offset;
+        i64 delta = deltas[i].delta;
+        i64 end = (i + 1 == deltas.size()) ? contents.size() : deltas[i + 1].offset;
+        i64 removed_bytes = get_removed_bytes(deltas, i);
+        memcpy(buf + offset + removed_bytes - delta,
+               contents.data() + offset + removed_bytes,
+               end - offset - removed_bytes);
+      }
+    }
+  } else {
+    copy_contents_to(ctx, buf, sh_size);
+  }
+
+  // Apply relocations
+  if (!ctx.arg.relocatable) {
+    if (shdr().sh_flags & SHF_ALLOC)
+      apply_reloc_alloc(ctx, buf);
+    else
+      apply_reloc_nonalloc(ctx, buf);
+  }
+}
+
+// Get the name of a function containin a given offset.
+template <typename E>
+std::string_view
+InputSection<E>::get_func_name(Context<E> &ctx, i64 offset) const {
+  for (Symbol<E> *sym : file.symbols)
+    if (sym->file == &file)
+      if (const ElfSym<E> &esym = sym->esym();
+          esym.st_shndx == shndx && esym.st_type == STT_FUNC &&
+          esym.st_value <= offset && offset < esym.st_value + esym.st_size)
+        return ctx.arg.demangle ? demangle(*sym) : sym->name();
+  return "";
+}
+
+// Test if the symbol a given relocation refers to has already been resolved.
+// If not, record that error and returns true.
+template <typename E>
+bool InputSection<E>::record_undef_error(Context<E> &ctx, const ElfRel<E> &rel) {
+  // If a relocation refers to a linker-synthesized symbol for a
+  // section fragment, it's always been resolved.
+  if (file.elf_syms.size() <= rel.r_sym)
+    return false;
+
+  Symbol<E> &sym = *file.symbols[rel.r_sym];
+  const ElfSym<E> &esym = file.elf_syms[rel.r_sym];
+
+  // If a symbol is defined in a comdat group, and the comdat group is
+  // discarded, the symbol may not have an owner. It is technically an
+  // violation of the One Definition Rule, so it is a programmer's fault.
+  if (!sym.file) {
+    Error(ctx) << *this << ": " << sym << " refers to a discarded COMDAT section"
+               << " probably due to an ODR violation";
+    return true;
+  }
+
+  auto record = [&] {
+    std::stringstream ss;
+    if (std::string_view source = file.get_source_name(); !source.empty())
+      ss << ">>> referenced by " << source << "\n";
+    else
+      ss << ">>> referenced by " << *this << "\n";
+
+    ss << ">>>               " << file;
+    if (std::string_view func = get_func_name(ctx, rel.r_offset); !func.empty())
+      ss << ":(" << func << ")";
+    ss << '\n';
+
+    typename decltype(ctx.undef_errors)::accessor acc;
+    ctx.undef_errors.insert(acc, {&sym, {}});
+    acc->second.push_back(ss.str());
+  };
+
+  // A non-weak undefined symbol must be promoted to an imported symbol
+  // or resolved to an defined symbol. Otherwise, we need to report an
+  // error or warn on it.
+  //
+  // Every ELF file has an absolute local symbol as its first symbol.
+  // Referring to that symbol is always valid.
+  bool is_undef = esym.is_undef() && !esym.is_weak() && sym.sym_idx;
+
+  if (is_undef && sym.esym().is_undef()) {
+    if (ctx.arg.unresolved_symbols == UNRESOLVED_ERROR && !sym.is_imported) {
+      record();
+      return true;
+    }
+    if (ctx.arg.unresolved_symbols == UNRESOLVED_WARN) {
+      record();
+      return false;
+    }
+  }
+
+  return false;
+}
+
+template <typename E>
+MergeableSection<E>::MergeableSection(Context<E> &ctx, MergedSection<E> &parent,
+                                      std::unique_ptr<InputSection<E>> &isec)
+  : parent(parent), p2align(isec->p2align), input_section(std::move(isec)) {
+  input_section->uncompress(ctx);
+
+  std::scoped_lock lock(parent.mu);
+  parent.members.push_back(this);
+}
+
+static size_t find_null(std::string_view data, i64 pos, i64 entsize) {
+  if (entsize == 1)
+    return data.find('\0', pos);
+
+  for (; pos <= data.size() - entsize; pos += entsize)
+    if (data.substr(pos, entsize).find_first_not_of('\0') == data.npos)
+      return pos;
+
+  return data.npos;
+}
+
+// Mergeable sections (sections with SHF_MERGE bit) typically contain
+// string literals. Linker is expected to split the section contents
+// into null-terminated strings, merge them with mergeable strings
+// from other object files, and emit uniquified strings to an output
+// file.
+//
+// This mechanism reduces the size of an output file. If two source
+// files happen to contain the same string literal, the output will
+// contain only a single copy of it.
+//
+// It is less common than string literals, but mergeable sections can
+// contain fixed-sized read-only records too.
+//
+// This function splits the section contents into small pieces that we
+// call "section fragments". Section fragment is a unit of merging.
+//
+// We do not support mergeable sections that have relocations.
+template <typename E>
+void MergeableSection<E>::split_contents(Context<E> &ctx) {
+  std::string_view data = input_section->contents;
+  if (data.size() > UINT32_MAX)
+    Fatal(ctx) << *input_section << ": mergeable section too large";
+
+  i64 entsize = parent.shdr.sh_entsize;
+
+  // Split sections
+  if (parent.shdr.sh_flags & SHF_STRINGS) {
+    for (i64 pos = 0; pos < data.size();) {
+      frag_offsets.push_back(pos);
+      size_t end = find_null(data, pos, entsize);
+      if (end == data.npos)
+        Fatal(ctx) << *input_section << ": string is not null terminated";
+      pos = end + entsize;
+    }
+  } else {
+    if (data.size() % entsize)
+      Fatal(ctx) << *input_section
+                 << ": section size is not multiple of sh_entsize";
+    frag_offsets.reserve(data.size() / entsize);
+
+    for (i64 pos = 0; pos < data.size(); pos += entsize)
+      frag_offsets.push_back(pos);
+  }
+
+  // Compute hashes for section pieces
+  HyperLogLog estimator;
+  hashes.reserve(frag_offsets.size());
+
+  for (i64 i = 0; i < frag_offsets.size(); i++) {
+    u64 hash = hash_string(get_contents(i));
+    hashes.push_back(hash);
+    estimator.insert(hash);
+  }
+
+  parent.estimator.merge(estimator);
+
+  static Counter counter("string_fragments");
+  counter += frag_offsets.size();
+}
+
+template <typename E>
+void MergeableSection<E>::resolve_contents(Context<E> &ctx) {
+  fragments.reserve(frag_offsets.size());
+  for (i64 i = 0; i < frag_offsets.size(); i++)
+    fragments.push_back(parent.insert(ctx, get_contents(i), hashes[i], p2align));
+
+  // Reclaim memory as we'll never use this vector again
+  hashes.clear();
+  hashes.shrink_to_fit();
+}
+
+using E = MOLD_TARGET;
+
+template bool cie_equals(const CieRecord<E> &, const CieRecord<E> &);
+template class InputSection<E>;
+template class MergeableSection<E>;
+
+} // namespace mold

src/jobs-unix.cc

@@ -0,0 +1,50 @@
+// Many build systems attempt to invoke as many linker processes as there
+// are cores, based on the assumption that the linker is single-threaded.
+// However, since mold is multi-threaded, such build systems' behavior is
+// not beneficial and just increases the overall peak memory usage.
+// On machines with limited memory, this could lead to an out-of-memory
+// error.
+//
+// This file implements a feature that limits the number of concurrent
+// mold processes to just 1 for each user. It is intended to be used as
+// `MOLD_JOBS=1 ninja` or `MOLD_JOBS=1 make -j$(nproc)`.
+
+#include "mold.h"
+
+#include <cstdlib>
+#include <fcntl.h>
+#include <pwd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+namespace mold {
+
+static int lock_fd = -1;
+
+void acquire_global_lock() {
+  char *jobs = getenv("MOLD_JOBS");
+  if (!jobs || jobs != "1"s)
+    return;
+
+  std::string path;
+  if (char *dir = getenv("XDG_RUNTIME_DIR"))
+    path = dir + "/mold-lock"s;
+  else
+    path = "/tmp/mold-lock-"s + getpwuid(getuid())->pw_name;
+
+  int fd = open(path.c_str(), O_WRONLY | O_CREAT | O_CLOEXEC, 0600);
+  if (fd == -1)
+    return;
+
+  if (lockf(fd, F_LOCK, 0) == -1)
+    return;
+  lock_fd = fd;
+}
+
+void release_global_lock() {
+  if (lock_fd != -1)
+    close(lock_fd);
+}
+
+} // namespace mold

src/jobs-win32.cc

@@ -0,0 +1,6 @@
+namespace mold {
+
+void acquire_global_lock() {}
+void release_global_lock() {}
+
+} // namespace mold