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bazel / crubit / c4df74167481a2de8de340375cde54739aaf36f6
commitc4df74167481a2de8de340375cde54739aaf36f6[log] [tgz]
authorGoogler <no-reply@google.com>Fri Jun 28 11:18:24 2024 -0700
committerCopybara-Service <copybara-worker@google.com>Fri Jun 28 11:19:20 2024 -0700
tree91aa615aed73f992ae17e1abedfbfaad3d1587e5
parentaa3d714e25da6e26aebd9146e1545f9619510125 [diff]
Use distinct evidence for reference type returns and arguments.

Nullability of pointers held by reference needs to be invariant, unlike bare pointers.

For reference/pointer-to-mutable-pointer parameters, this revealed a limitation of our post-transfer-function evidence collection, due to the treatment of these parameters as output parameters that leave the arguments as Unknown by the time we are collecting evidence.

PiperOrigin-RevId: 647742932
Change-Id: I0f634892373d99b1b94ff982e8392cc3a2f729bf
4 files changed
tree: 91aa615aed73f992ae17e1abedfbfaad3d1587e5
  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