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bazel / crubit / 4ed35f60051aa7c1c2af79618fd7df4a8fad3eae
commit4ed35f60051aa7c1c2af79618fd7df4a8fad3eae[log] [tgz]
authorGoogler <no-reply@google.com>Thu Jun 13 07:49:50 2024 -0700
committerCopybara-Service <copybara-worker@google.com>Thu Jun 13 07:54:57 2024 -0700
treec97e70b3bfd4d6c37cdaf4abd8761f084a21ad65
parent3aa14a1d11d0a4d2b50a310fe77fa6d396b4c744 [diff]
Infer stronger intent from non-literal nullable default member initializers.

NULLABLE_DEFAULT_MEMBER_INITIALIZER evidence is considered in a soft no-conflict rule, subordinate to other evidence of Nonnull-ness, as literal nullptrs are often used simply to turn uninitialized-memory bugs into louder nullptr dereference crashes in cases where the pointer is still expected to be never null after construction of the containing object. ASSIGNED_TO_NULLABLE is more aggressive evidence, which will cause a conflict if we also see evidence requiring the pointer to be marked Nonnull, and we will now use this for cases where the default member initializer is a more complex nullable form than literal nullptr, which likely indicates more explicit Nullable intent.

PiperOrigin-RevId: 642991495
Change-Id: I8f0d7cc232748cbb82c13ee5f500ba1e26fd0774
6 files changed
tree: c97e70b3bfd4d6c37cdaf4abd8761f084a21ad65
  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