gecko-dev/build/build-clang
Nathan Froyd 37d0db29a9 Bug 1551690 - be more specific about the LLVM target on OS X; r=nalexander
Our current OS X builds use `--target=x86_64-darwin11` (which
corresponds to OS X 10.7).  This target is problematic for two reasons:

* We're actually targeting for OS X 10.9 (`MACOSX_DEPLOYMENT_TARGET`);
* It's slightly different from the default Rust target.

Let's address these problems in reverse order: differences from the Rust
target are bad, because the `--target` we provide to `clang` and the
Rust target find their way into LLVM bitcode files and the linker will
refuse to link together bitcode files that have incompatible targets.

Why are the two incompatible?  The current `--target` doesn't have a
"vendor" in triple-speak, whereas the Rust one has "apple" as the
vendor (`x86_64-apple-darwin`) We therefore need to change the
`--target` we pass to `clang` to have a vendor of "apple".

This need is behind the {init,toolchain}.configure changes,
but it has ramifications elsewhere, because `clang` looks for
`--target`-prefixed build tools.  So we have to change the `--target`
for cctools to get the right tool prefixes and we have to change the
`--target` for building clang ourselves so that *those* builds can find
the newly renamed cctools.

Once we've done, that's really enough; we don't *need to address the
first problem: While the `--target` might be `x86_64-apple-darwin11`,
both `clang` and `rustc` will dynamically choose the target triple that
eventually lands in LLVM bitcode files based on
`MACOSX_DEPLOYMENT_TARGET`, which we set in all builds.  But the current
target is slightly misleading, and the cctools don't need to be prefixed
with a particular Darwin version, since they work for all Darwin
targets.  Let's just drop the "11" from the `--target` and eliminate a
little bit of confusion.

Differential Revision: https://phabricator.services.mozilla.com/D31128

--HG--
extra : moz-landing-system : lando
2019-05-21 17:53:44 +00:00
..
android-mangling-error.patch
build-clang.py Bug 1551690 - be more specific about the LLVM target on OS X; r=nalexander 2019-05-21 17:53:44 +00:00
clang-4.0-linux64.json
clang-7-linux64.json
clang-8-android.json
clang-8-linux64-aarch64-cross.json
clang-8-linux64.json
clang-8-macosx64.json Bug 1551690 - be more specific about the LLVM target on OS X; r=nalexander 2019-05-21 17:53:44 +00:00
clang-8-mingw.json
clang-tidy-8.patch
clang-tidy-linux64.json
clang-tidy-macosx64.json Bug 1551690 - be more specific about the LLVM target on OS X; r=nalexander 2019-05-21 17:53:44 +00:00
clang-tidy-win64.json
clang-win64.json
compiler-rt-cross-compile.patch Bug 1551690 - be more specific about the LLVM target on OS X; r=nalexander 2019-05-21 17:53:44 +00:00
compiler-rt-no-codesign.patch
downgrade-mangling-error.patch
find_symbolizer_linux.patch
llvm-debug-frame.patch
loosen-msvc-detection.patch
mingwclang-llvm-objcopy-COFF-Add-support-for-removing-sections.patch
mingwclang-llvm-objcopy-COFF-Clear-the-unwritten-tail-of-coff_s.patch
mingwclang-llvm-objcopy-COFF-Error-out-on-use-of-unhandled-opti.patch
mingwclang-llvm-objcopy-COFF-Fix-handling-of-aux-symbols-for-bi.patch
mingwclang-llvm-objcopy-COFF-Implement-only-keep-debug.patch
mingwclang-llvm-objcopy-COFF-Implement-only-section.patch
mingwclang-llvm-objcopy-COFF-Implement-strip-debug.patch
mingwclang-llvm-objcopy-COFF-Remove-a-superfluous-namespace-qua.patch
mingwclang-llvm-objcopy-COFF-Update-symbol-indices-in-weak-exte.patch
mingwclang-llvm-objcopy-Consistently-use-createStringError-inst.patch
mingwclang-llvm-objcopy-Return-Error-from-Buffer-allocate-ELF-W.patch
mingwclang-Reapply-llvm-objcopy-COFF-Implement-add-gnu-debuglin.patch
r277806.patch
r285657.patch
r289565-for-3.9.patch
r313872.patch
r322325.patch
r322401.patch
r325356.patch
r339636.patch
r350774.patch
r355141-arm64-cfg.patch
README
rename_gcov_flush_7.patch
rename_gcov_flush.patch
revert-r355311.patch
static-llvm-symbolizer.patch
unpoison-thread-stacks.patch
workaround-issue38586.patch

build-clang.py
==============

A script to build clang from source.

```
usage: build-clang.py [-h] -c CONFIG [--clean]

optional arguments:
  -h, --help            show this help message and exit
  -c CONFIG, --config CONFIG
                        Clang configuration file
  --clean               Clean the build directory
```

Pre-requisites
--------------
* Working build toolchain.
* Subversion
* CMake
* Ninja
* Python 2.7

Please use the latest available CMake for your platform to avoid surprises.

Config file format
------------------

build-clang.py accepts a JSON config format with the following fields:

* llvm_revision: The LLVM SVN revision to build.
* stages: Use 1, 2, or 3 to select different compiler stages.  The default is 3.
* llvm_repo: SVN path to the LLVM repo.
* clang_repo: SVN path to the Clang repo.
* extra_repo: SVN path to the clang-tools-extra repo.
* lld_repo: SVN path to the lld repo.
* compiler_repo: SVN path to the compiler-rt repo.
* libcxx_repo: SVN path to the libcxx repo.
* libcxxabi_repo: SVN path to the libcxxabi repo.
* python_path: Path to the Python 2.7 installation on the machine building clang.
* gcc_dir: Path to the gcc toolchain installation, only required on Linux.
* cc: Path to the bootsraping C Compiler.
* cxx: Path to the bootsraping C++ Compiler.
* as: Path to the assembler tool.
* ar: Path to the library archiver tool.
* ranlib: Path to the ranlib tool (optional).
* libtool: Path to the libtool tool (optional).
* ld: Path to the linker.
* patches: Optional list of patches to apply.
* build_type: The type of build to make.  Supported types: Release, Debug, RelWithDebInfo or MinSizeRel.
* build_libcxx: Whether to build with libcxx.  The default is false.
* build_clang_tidy: Whether to build clang-tidy with the Mozilla checks imported.  The default is false.
* osx_cross_compile: Whether to invoke CMake for OS X cross compile builds.
* assertions: Whether to enable LLVM assertions.  The default is false.

Environment Variables
---------------------

The following environment variables are used for cross-compile builds targeting OS X on Linux.

* CROSS_CCTOOLS_PATH: Path to the cctools directory where the cross compiler toolchain is located.
* CROSS_SYSROOT: Path to the OS X SDK directory for cross compile builds.