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bazel/rules_cc/9b321830c1a84415bc139d29e5864b3bb7f1b474
commit
9b321830c1a84415bc139d29e5864b3bb7f1b474
[log]
author
David Zbarsky <dzbarsky@gmail.com>
Sun Jul 05 14:42:29 2026 -0700
committer
Copybara-Service <copybara-worker@google.com>
Sun Jul 05 14:42:47 2026 -0700
tree
4e3ccc417203bf71a00a74f45f8d8776f60b4478
parent
1a208337d445c5f736fc17be06c59fd29f46819e [diff]
Add macOS ThinLTO arguments

Copybara Import from https://github.com/bazelbuild/rules_cc/pull/748

BEGIN_PUBLIC
Add macOS ThinLTO arguments (#748)

The `thin_lto` feature currently sends GNU plugin options to every non-Windows linker. Mach-O LLD implements distributed ThinLTO with direct `--thinlto-*` options instead, so macOS indexing actions fail when they inherit the ELF spellings. This selects Mach-O LLD's direct indexing, imports, prefix replacement, suffix replacement, and merged-object options on macOS while preserving the existing arguments on other platforms.

The merged regular LTO object uses `--lto-obj-path`, which is proposed in llvm/llvm-project#203365. Mach-O LLD's existing `-object_path_lto` treats a ThinLTO path as a directory and generates `0.<arch>.lto.o`; rules_cc requires `thinlto_merged_object_file` to be an exact declared output consumed by the final link.

Validation: `bazel test //tests/rule_based_toolchain/legacy_features_as_args:thin_lto_macos_test --test_output=errors`.

Closes #748
END_PUBLIC

COPYBARA_INTEGRATE_REVIEW=https://github.com/bazelbuild/rules_cc/pull/748 from dzbarsky:codex/macos-thinlto 3f1e877a88cc9642555ad4f809d98b737782e042
PiperOrigin-RevId: 942933114
Change-Id: Ib446c59e811813913eab36e327d543c8fe4cd434
3 files changed
tree: 4e3ccc417203bf71a00a74f45f8d8776f60b4478
  1. .bazelci/
  2. .bcr/
  3. .github/
  4. cc/
  5. docs/
  6. examples/
  7. tests/
  8. .bazelignore
  9. .bazelrc
  10. .gitignore
  11. AUTHORS
  12. BUILD
  13. CODEOWNERS
  14. CONTRIBUTING.md
  15. googletest.patch
  16. ISSUE_TEMPLATE.md
  17. LICENSE
  18. local_bazel.bzl
  19. MODULE.bazel
  20. README.md
  21. WORKSPACE
  22. WORKSPACE.bzlmod
README.md

C++ rules for Bazel

  • Postsubmit Build status

This repository contains C, C++, and Objective-C language support for the Bazel build system.

For this module's main reference, see the Bazel documentation.

Get Started

Install Bazel

Follow the official instructions to Install Bazel.

Add rules_cc to your MODULE.bazel

Add the latest release to your MODULE.bazel project file.

Declare a build target

In a BUILD.bazel file, import and use the rules:

load("@rules_cc//cc:cc_binary.bzl", "cc_binary")

cc_binary(
    name = "hello_world",
    srcs = ["hello_world.cc"],
)

Build and run your project

Build and run your C/C++ binary with one command:

$ bazel run hello_world

To build the project without running the binary, use Bazel's build subcommand:

$ bazel build hello_world

Toolchains

Default autoconfigured toolchain

rules_cc includes an auto-configured toolchain that uses the local compiler installed on the host machine.

You can disable the autoconfigured C/C++ toolchain by adding the following Bazel flag to your project's .bazelrc file:

--repo_env=BAZEL_DO_NOT_DETECT_CPP_TOOLCHAIN=1

Hermetic toolchains

Configuring a hermetic toolchain makes your build more deterministic. rules_cc itself does not yet offer a hermetic toolchain distribution. Other community owned and maintained projects offer hermetic C/C++ toolchains:

Contributing

Bazel and rules_cc are the work of many contributors. We appreciate your help!

To contribute, please read the contribution guidelines: CONTRIBUTING.md.

Note that the rules_cc use the GitHub issue tracker for bug reports and feature requests only. For asking questions see: