llvm-capstone/lld
Fangrui Song ed399d508f [ELF] Make SHF_GNU_RETAIN sections GC roots
binutils 2.36 introduced the new section flag SHF_GNU_RETAIN (for ELFOSABI_GNU &
ELFOSABI_FREEBSD) to mark a sections as a GC root. Several LLVM side toolchain
folks (including me) were involved in the design process of SHF_GNU_RETAIN and
were happy with this proposal.

Currently GNU ld only respects SHF_GNU_RETAIN semantics for ELFOSABI_GNU &
ELFOSABI_FREEBSD object files
(https://sourceware.org/bugzilla/show_bug.cgi?id=27282).  GNU ld sets EI_OSABI
to ELFOSABI_GNU for relocatable output
(https://sourceware.org/bugzilla/show_bug.cgi?id=27091). In practice the single
value EI_OSABI is neither a good indicator for object file compatibility, nor a
useful mechanism marking used ELF extensions.

For input, we respect SHF_GNU_RETAIN semantics even for ELFOSABI_NONE object
files. This is compatible with how LLD and GNU ld handle (mildly useful) STT_GNU_IFUNC
/ (emitted by GCC, considered misfeature by some folks) STB_GNU_UNIQUE input.
(As of LLVM 12.0.0, the integrated assembler does not set ELFOSABI_GNU for
STT_GNU_IFUNC/STB_GNU_UNIQUE).
Arguably STT_GNU_IFUNC/STB_GNU_UNIQUE probably need indicators in object files
but SHF_GNU_RETAIN is more likely accepted by more OSABI platforms.

For output, we take a step further than GNU ld: we don't promote ELFOSABI_NONE
to ELFOSABI_GNU for all output.

Differential Revision: https://reviews.llvm.org/D95749
2021-02-04 09:23:01 -08:00
..
cmake/modules lld: Let find_package(LLD) work 2020-05-14 09:59:53 -04:00
COFF Revert "[PDB] Defer relocating .debug$S until commit time and parallelize it" 2021-01-28 13:17:27 -08:00
Common [lld/mac] Add --reproduce option 2020-11-30 08:40:21 -05:00
docs Bump the trunk major version to 13 2021-01-26 19:37:55 -08:00
ELF [ELF] Make SHF_GNU_RETAIN sections GC roots 2021-02-04 09:23:01 -08:00
include/lld [lld][WebAssembly] Add support for handling table symbols 2021-01-14 11:13:13 +01:00
lib [MachO] Fix enum-int mismatch warning 2020-12-28 17:39:41 +01:00
MachO [lld-macho] Try to fix Windows build 2021-02-03 16:05:23 -05:00
MinGW [LLD] [MinGW] Pass the --demangle and --no-demangle options to the COFF linker 2021-01-07 10:02:19 +02:00
test [ELF] Make SHF_GNU_RETAIN sections GC roots 2021-02-04 09:23:01 -08:00
tools/lld lld: Fix darwinnew symlink name added in e16c0a9a68 2020-11-24 11:06:51 -05:00
unittests Use INTERFACE_COMPILE_OPTIONS to disable -Wsuggest-override for any target that links to gtest 2020-07-27 08:37:01 -07:00
utils
wasm [WebAssembly] fixed wasm64 data segment init exp not 64-bit 2021-02-01 11:32:50 -08:00
.clang-format
.clang-tidy [lld] Add .clang-tidy to customize readability-identifier-naming.{Member,Parameter,Variable}Case => camelBack 2020-03-09 08:26:41 -07:00
.gitignore
CMakeLists.txt Revert "[CMake] Actually require python 3.6 or greater" 2021-01-29 12:03:32 -08:00
CODE_OWNERS.TXT Add code owners of new MachO port 2020-09-02 19:32:12 -07:00
LICENSE.TXT
README.md [doc] Place sha256 in lld/README.md into backticks 2021-01-12 10:19:40 -08:00

LLVM Linker (lld)

This directory and its subdirectories contain source code for the LLVM Linker, a modular cross platform linker which is built as part of the LLVM compiler infrastructure project.

lld is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt.

Benchmarking

In order to make sure various developers can evaluate patches over the same tests, we create a collection of self contained programs.

It is hosted at https://s3-us-west-2.amazonaws.com/linker-tests/lld-speed-test.tar.xz

The current sha256 is 10eec685463d5a8bbf08d77f4ca96282161d396c65bd97dc99dbde644a31610f.