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bazel / crubit / f1189ffb52a57208de05f5550be106a2ecf0070e
commitf1189ffb52a57208de05f5550be106a2ecf0070e[log] [tgz]
authorDevin Jeanpierre <jeanpierreda@google.com>Tue Mar 19 21:43:57 2024 -0700
committerCopybara-Service <copybara-worker@google.com>Tue Mar 19 21:44:55 2024 -0700
treee309855b49f9f23dffbef80dc963ebc78ab77ab8
parent96cf315f4912498f730e1e602576901f8e650b45 [diff]
Add a `--config=crubit-genfiles` to inspect generated C++/Rust bindings.

Note that, unlike most `--config`s, this is not actually useful for building binaries or anything like that. This is just a global shortcut for the aspect and its outputs. So it is primarily useful with `build` (for end users who want to look at bindings), and with `aquery` (for developers).

(I think there's no easy way to visit the aspect using `query` or `cquery` or the like, certainly not just with the `--aspects` flag alone.)

PiperOrigin-RevId: 617391700
Change-Id: I2df3964a6f5444c0089e8bc2af9d63ce76c08779
3 files changed
tree: e309855b49f9f23dffbef80dc963ebc78ab77ab8
  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. README.md
  22. WORKSPACE
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