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bazel / crubit / ef9113f3e99c20ab2095dd4cd5e98f9aaa3b69db
commitef9113f3e99c20ab2095dd4cd5e98f9aaa3b69db[log] [tgz]
authorDmitri Gribenko <dmitrig@google.com>Mon Jul 08 00:55:00 2024 -0700
committerCopybara-Service <copybara-worker@google.com>Mon Jul 08 00:58:48 2024 -0700
tree9963c6f78a6e9b2b620a7c855f5e51458f2d8e48
parent44239929497742fae03c677c4b80a868e549ba78 [diff]
Make Bazel tests for Crubit feature infra independent of production features

We update the definitions of feature sets like "supported" and "experimental"
for release engineering reasons. The expansion of these feature sets is
hardcoded in a Bazel test. As a result, when we update the feature sets to
release a feature or clean up a feature flag, we have to update a Bazel test.

This change makes Bazel tests use special test-only feature set names that are
stable, thus eliminating the churn in the Bazel test.

PiperOrigin-RevId: 650151945
Change-Id: I2620a2dde83fd341f06f03f20f2ea3818fe0852b
3 files changed
tree: 9963c6f78a6e9b2b620a7c855f5e51458f2d8e48
  1. .bazelci/
  2. bazel/
  3. cc_bindings_from_rs/
  4. common/
  5. docs/
  6. examples/
  7. features/
  8. lifetime_analysis/
  9. lifetime_annotations/
  10. migrator/
  11. nullability/
  12. rs_bindings_from_cc/
  13. support/
  14. .bazelrc
  15. .gitignore
  16. BUILD
  17. Cargo.lock
  18. CODE_OF_CONDUCT
  19. CONTRIBUTING
  20. LICENSE
  21. MODULE.bazel
  22. README.md
  23. WORKSPACE.bzlmod
README.md

Crubit: C++/Rust Bidirectional Interop Tool

Build status

NOTE: Crubit currently expects deep integration with the build system, and is difficult to deploy to environments dissimilar to Google's monorepo. We do not have our tooling set up to accept external contributions at this time.

Crubit is a bidirectional bindings generator for C++ and Rust, with the goal of integrating the C++ and Rust ecosystems.

Status

Support for calling FFI-friendly C++ from Rust is in progress.

Support for calling Rust from C++ will arrive in 2024H2.

Example

Consider the following C++ function:

extern "C" bool IsGreater(int lhs, int rhs);

This function, if present in a header file which is processed by Crubit, becomes callable from Rust as if it were defined as:

pub fn IsGreater(lhs: ffi::c_int, rhs: ffi::c_int) -> bool {...}

Note: There are some temporary restrictions on the API shape. For example, functions that are not extern "C", or that accept a type like std::string, can't be called from Rust directly via Crubit. These restrictions will be relaxed over time.

Getting Started

Here are some resources for getting started with Crubit:

  • Rust Bindings for C++ Libraries is a detailed walkthrough on how to use C++ from Rust using Crubit.

  • The examples/cpp/ directory has copy-pastable examples of calling C++ from Rust, together with snapshots of what the generated Rust interface looks like.

Building Crubit

$ apt install clang lld bazel
$ git clone git@github.com:google/crubit.git
$ cd crubit
$ bazel build --linkopt=-fuse-ld=/usr/bin/ld.lld //rs_bindings_from_cc:rs_bindings_from_cc_impl

Using a prebuilt LLVM tree

$ git clone https://github.com/llvm/llvm-project
$ cd llvm-project
$ CC=clang CXX=clang++ cmake -S llvm -B build -DLLVM_ENABLE_PROJECTS='clang' -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=install
$ cmake --build build -j
$ # wait...
$ cmake --install build
$ cd ../crubit
$ LLVM_INSTALL_PATH=../llvm-project/install bazel build //rs_bindings_from_cc:rs_bindings_from_cc_impl