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bazel / crubit / 4f07a49e71c750cd9c469e31d194ef6969af9da1
commit4f07a49e71c750cd9c469e31d194ef6969af9da1[log] [tgz]
authorGoogler <no-reply@google.com>Fri Jul 19 07:52:38 2024 -0700
committerCopybara-Service <copybara-worker@google.com>Fri Jul 19 07:54:00 2024 -0700
tree4529f396c68e47ca1fbf45d159afef7198b54d44
parentf945748713d3474199c740ede79b1ddc759d88ee [diff]
Use the initializer Expr that is a child of the constructor now that CXXDefaultInitExprs may be copied in the AST.

This fixes a crash that I believe did not exist before https://github.com/llvm/llvm-project/pull/91879. The CXXDefaultInitExpr that is the in-class member initializer is now not the same object that is referenced through the constructor's initializers, so we could no longer retrieve the correct environment values for the expressions involved. We need to use the object referenced by the constructor's initializers.

The minimal crash repro I could find still needed `#include <assert.h>`, so isn't an option for unit tests in collect_evidence_test.cc:

```cpp
#include <assert.h>

#include <memory>

int* g;

class C {
  C() {}

  std::unique_ptr<int, void (*)(int*)> field_{
      g, [](int*) { __assert_fail("", __builtin_FILE(), 0, ""); }};
};
```

PiperOrigin-RevId: 654006679
Change-Id: If4b8455132ae1b637be3544e15e63bcdf962772b
2 files changed
tree: 4529f396c68e47ca1fbf45d159afef7198b54d44
  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