| commit | 162d21f4ea71f00bae5cf6988838e9f1d896f733 | [log] [tgz] |
|---|---|---|
| author | Devin Jeanpierre <jeanpierreda@google.com> | Tue Nov 21 15:14:00 2023 -0800 |
| committer | Copybara-Service <copybara-worker@google.com> | Tue Nov 21 15:14:42 2023 -0800 |
| tree | f9c9c20a318bcdb94166f059203ebc5d9b60355a | |
| parent | ea2efd7c87e3170109ccdffd20842ff0618689ab [diff] |
Emit round-trip type annotations for C++ types.
A Rust type which was originally a C++ type gets an annotation to the effect of "I was originally, in C++, foo::Bar!". This is, for the moment, ignored. In a later CL, we can then see this, and when generating C++ bindings for the type, instead go "wait, no, nevermind, use the original type!"
We did discuss different ways to do this, in the end the conclusion we reached (AIUI) is that all the options are bad. I picked the easiest one to implement, and the one I view as most likely to be what we want to pursue in the long term. Since this is not something intended for end users, we still reserve the ability to rework it later.
(Also, honestly, even if we _did_ hand it out to end users, the refactoring to translate it to something else should be relatively straightforward.)
---
A quick note on structure:
The attribute, as written, is `__crubit::annotate`. This is mostly an implementation convenience: we can scan for all attributes named `__crubit::annotate` and search for our attribute in particular. Since, once again, this should not be exposed to end-users, it's fine. We're just picking whatever is easier for now.
If end users end up using these annotations, we might hide it behind a proc-macro, like `#[crubit::cc_type("xyz")]`, which expands to `#[__crubit::annotate(cc_type="...")]`
PiperOrigin-RevId: 584442104
Change-Id: I8f7416e1afcc75d72130894f99c4ecba1d0e20fd
Crubit is an experimental bidirectional bindings generator for C++ and Rust.
Please don‘t use, this is an experiment and we don’t yet know where will it take us. There will be breaking changes without warning. Unfortunately, we can't take contributions at this point.
Crubit allows for C++ code and Rust code to call each other without manually wrapping the APIs in an FFI-friendly interop layer. For example, a C++ function like this:
bool IsAbsPath(std::string_view path);
... becomes callable from Rust as if it were defined as:
pub fn IsAbsPath(path: std::string_view) -> bool {...}
Crubit automatically generates ABI-compatible bindings for structs (which can be passed both by value and by reference), functions, and methods, for a large variety of types. (Trivial types, nontrivial types, templated types, etc.)
$ 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
$ 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