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bazel / crubit / 061800efe7811ea5f4e188c382e054c5e537bb58
commit061800efe7811ea5f4e188c382e054c5e537bb58[log] [tgz]
authorDmitri Gribenko <dmitrig@google.com>Tue Jul 02 08:04:57 2024 -0700
committerCopybara-Service <copybara-worker@google.com>Tue Jul 02 08:05:57 2024 -0700
treeb3660afa6de1d6c0561dbe9df26ae15bbce98364
parent8373fe986b52e97687bc4dcb3da373745dc7a48e [diff]
Unbreak Crubit tests with the latest Rust compiler by allowing dead code in tests

The new version of the Rust compiler has started to identify dead code in our
tests, for example:

```rust
error: struct `SomeStruct` is never constructed
 --> <crubit_unittests.rs>:2:28
  |
2 |                 pub struct SomeStruct(f32);
  |                            ^^^^^^^^^^
  |
  = note: `-D dead-code` implied by `-D warnings`
  = help: to override `-D warnings` add `#[allow(dead_code)]`

error: aborting due to 1 previous error
```
PiperOrigin-RevId: 648720856
Change-Id: I630d5ff7747f0c5df4be7308c716c44b862b4318
1 file changed
tree: b3660afa6de1d6c0561dbe9df26ae15bbce98364
  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