Files
carbon-lang/MODULE.bazel
T
d49cb3ecfb Start building Clang runtimes on-demand (#5338)
This is the first step to having Clang's runtime libraries fully
available for the Carbon toolchain. This PR focuses on the lowest level
runtimes, the CRT files and the builtins library.

The goal is to intercept Clang runs where it needs these
target-dependent pieces to be available, and build them on demand using
our Clang-running infrastructure. This avoids most of the subprocess
overhead, but there is still some due to missing features in Clang.

This requires exporting the sources for these runtimes from the Bazel
build, and installing them in our target-independent resource directory.
We then build a simplified "build" of these sources within the
`ClangRunner` itself to produce the specific artifacts and layout
expected by Clang.

It also required fixing our use of Clang on macOS to have a default
system root in order to successfully compile or link.

It also required cleaning up how the `ClangRunner` used target
information more generally -- instead of taking the target as
a constructor parameter, it manages its target internally and relies on
the Clang target-specifying command line flags.

I looked at whether we could split this into another layer separate from
the `ClangRunner`, but that proved frustratingly difficult to manage.
While we support building these on-demand as part of a detected link,
that doesn't seem feasible as we don't have the necessary separation
between compilation runs of Clang and link runs of Clang. However,
I have tried to factor the internals to provide as clear of separation
as I could across these.

I have also created a stand-alone subcommand to directly build the
runtimes which allows for easy testing. It also supports building them
into a specific directory, and that directory can in turn be passed to
a Clang invocation. This is designed to work both at the API level with
`ClangRunner` and at the subcommand level.

Currently, the only part of the commandline that is detected and
forwarded to the runtimes build is the target. Eventually, the plan is
to expand this so that we can build a maximally tailored set of runtimes
for a given compilation.

The other big TODO here is to actually implement caching storage of
these runtimes so they aren't built on every execution. Right now, this
uses a somewhat hack-y build of a temporary directory, but this isn't
expected to be suitable long-term. Building these runtimes on *every*
link makes those commands take approximately 15 seconds with an ASan
build like our default development build, and just over 2 seconds in an
optimized build. Because of this, I've kept all of this disabled by
default for now. The goal is that once caching and some other
improvements land, we can enable this by default.

---------

Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
Co-authored-by: Richard Smith <richard@metafoo.co.uk>
2025-08-22 03:05:21 +00:00

143 lines
5.6 KiB
Python

# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
# Exceptions. See /LICENSE for license information.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
"""Bazel modules.
`MODULE.bazel.lock` may change locally when `bazel` is executed. This means one
of:
1. An input is changing, typically `MODULE.bazel` or `.bazelversion`.
- Running `bazel mod deps` provides a canonical update to
`MODULE.bazel.lock`; include the changes.
- GitHub test actions may also identify platform-specific lockfile
updates.
2. The host platform hasn't yet been added to the lock file.
- Platforms tested with GitHub actions are kept up-to-date. Other
platforms may fall out of sync due to `bazel` or dependency changes,
and should be updated with a PR the same way a platform is added.
- Running `bazel mod deps` provides a canonical update to
`MODULE.bazel.lock`; create a PR with those changes in order to include
the host platform.
"""
module(name = "carbon")
http_archive = use_repo_rule(
"@bazel_tools//tools/build_defs/repo:http.bzl",
"http_archive",
)
bazel_dep(name = "abseil-cpp", version = "20250512.1")
bazel_dep(name = "bazel_skylib", version = "1.8.1")
bazel_dep(name = "google_benchmark", version = "1.9.4")
bazel_dep(name = "googletest", version = "1.17.0")
bazel_dep(name = "re2", version = "2024-07-02.bcr.1")
bazel_dep(name = "rules_cc", version = "0.1.4")
bazel_dep(name = "rules_pkg", version = "1.1.0")
bazel_dep(name = "rules_shell", version = "0.5.0")
bazel_dep(name = "tcmalloc", version = "0.0.0-20250331-43fcf6e")
bazel_dep(name = "tree-sitter-bazel", version = "0.24.4")
# The registry only has an old version. We use that here to avoid a miss but
# override it with a newer version.
bazel_dep(name = "libpfm", version = "4.11.0")
libpfm_version = "4.13.0"
# The official site is https://perfmon2.sourceforge.net/, but SourceForge makes
# it difficult to download from bazel. On GitHub action runners,
# https://git.code.sf.net/p/perfmon2/libpfm4 seems to be blocked. As a
# consequence, use a mirror.
archive_override(
module_name = "libpfm",
integrity = "sha256-sGBx1+UoQCplBCc+pwA1Tr/PS2L/4jnLZHH82wSuPz0=",
patch_strip = 1,
patches = ["@//bazel/libpfm:0001-Introduce-a-simple-native-Bazel-build.patch"],
strip_prefix = "libpfm4-{0}".format(libpfm_version),
urls = ["https://github.com/wcohen/libpfm4/archive/v{0}.tar.gz".format(libpfm_version)],
)
bazel_dep(name = "bazel_clang_tidy", dev_dependency = True)
git_override(
module_name = "bazel_clang_tidy",
# HEAD as of 2025-01-09.
commit = "db677011c7363509a288a9fb3bf0a50830bbf791",
remote = "https://github.com/erenon/bazel_clang_tidy.git",
)
bazel_cc_toolchain = use_extension(
"//bazel/cc_toolchains:clang_configuration.bzl",
"clang_toolchain_extension",
)
use_repo(bazel_cc_toolchain, "bazel_cc_toolchain")
register_toolchains("@bazel_cc_toolchain//:all")
bazel_dep(name = "hedron_compile_commands", dev_dependency = True)
git_override(
module_name = "hedron_compile_commands",
# HEAD as of 2025-01-09.
commit = "4f28899228fb3ad0126897876f147ca15026151e",
remote = "https://github.com/hedronvision/bazel-compile-commands-extractor.git",
)
boost_unordered_version = "1.85.0"
http_archive(
name = "boost_unordered",
build_file = "@//:third_party/boost_unordered/BUILD.bazel",
integrity = "sha256-2dQ4IQH/xFiK1iWCkrMYLeR8zsSQqGchKOdTuf1u0zI=",
strip_prefix = "boost_unordered-{0}".format(boost_unordered_version),
urls = ["https://github.com/MikePopoloski/boost_unordered/archive/v{0}.tar.gz".format(boost_unordered_version)],
)
# Required for llvm-project.
bazel_dep(name = "platforms", version = "1.0.0")
bazel_dep(name = "zlib", version = "1.3.1.bcr.6", repo_name = "llvm_zlib")
bazel_dep(name = "zstd", version = "1.5.7", repo_name = "llvm_zstd")
###############################################################################
# llvm-project
###############################################################################
# We pin to specific upstream commits and try to track top-of-tree reasonably
# closely rather than pinning to a specific release.
# HEAD as of 2025-08-09.
llvm_project_version = "fc44a4fcd3c54be927c15ddd9211aca1501633e7"
# Load a repository for the raw llvm-project, pre-overlay.
http_archive(
name = "llvm-raw",
build_file_content = "# empty",
integrity = "sha256-0iiuvlWDxpxOSP16jhSePSLuba+urpQAlGcUPTLZv8Q=",
patch_args = ["-p1"],
patches = [
"@carbon//bazel/llvm_project:0001_Patch_for_mallinfo2_when_using_Bazel_build_system.patch",
"@carbon//bazel/llvm_project:0002_Added_Bazel_build_for_compiler_rt_fuzzer.patch",
"@carbon//bazel/llvm_project:0003_Comment_out_unloaded_proto_library_dependencies.patch",
"@carbon//bazel/llvm_project:0004_Introduce_filegroups_for_compiler_rt_builtins_runtime.patch",
],
strip_prefix = "llvm-project-{0}".format(llvm_project_version),
urls = ["https://github.com/llvm/llvm-project/archive/{0}.tar.gz".format(llvm_project_version)],
)
# Apply the overlay to produce llvm-project.
llvm_project = use_extension(
"//bazel/llvm_project:llvm_project.bzl",
"llvm_project",
)
use_repo(llvm_project, "llvm-project")
###############################################################################
# Python
###############################################################################
bazel_dep(name = "rules_python", version = "1.5.1")
python = use_extension("@rules_python//python/extensions:python.bzl", "python")
python.toolchain(
python_version = "3.11",
)
use_repo(python, "python_versions")