azerupi / rust-bindgen

binding generator for rust language

Servo's rust-bindgen

A binding generator for the Rust language.

This is a fork of crabtw/rust-bindgen designed to work on C++ code as well.

Currently this is being used for Servo's SpiderMonkey bindings, and also for the Stylo project.

Requirements

The current generator runs on with clang 3.8, but can also run with clang 3.9 with more features (such as detection of inlined functions).

Installing clang 3.8

OSX

# brew install llvm38

On Debian-based Linuxes

# apt-get install llvm-3.8-dev libclang-3.8-dev

Adding the LLVM repos to get version 3.8 may be necessary, see http://apt.llvm.org/.

Arch

# pacman -S clang clang-tools-extra

Getting clang 3.9

From a package manager

Clang 3.9 has ben released about a month ago, and some package managers already provide it.

For example, for MacPorts:

$ port install clang-3.9
$ LIBCLANG_PATH=/opt/local/libexec/llvm-3.9/lib \
  LD_LIBRARY_PATH=/opt/local/libexec/llvm-3.9/lib \
  cargo build

From source

If your package manager doesn't yet offer Clang 3.9, you'll need to build from source. For that, follow the instructions here.

Those instructions list optional steps. For bindgen:

• Checkout and build clang
• Checkout and build the extra-clang-tools
• Checkout and build the compiler-rt
• You do not need to checkout or build libcxx

Building

$ cargo build --features llvm_stable

If you want a build with extra features (llvm 3.9) then you can use:

$ LIBCLANG_PATH=path/to/clang-3.9/build/lib \
  LD_LIBRARY_PATH=path/to/clang-3.9/build/lib \
    cargo build

Library usage with build.rs

In Cargo.toml:

[package]
...
build = "build.rs"

[build-dependencies.libbindgen]
git = "https://github.com/servo/rust-bindgen"
features = ["llvm_stable"]

In build.rs:

extern crate libbindgen;

fn main() {
  let _ = libbindgen::builder()
    .header("example.h")
    .use_core()
    .generate().unwrap()
    .write_to_file(concat!(env!("OUT_DIR"), "/example.rs"));
}

In src/main.rs:

include!(concat!(env!("OUT_DIR"), "/example.rs"));

Command Line Usage

There are a few options documented when running ./bindgen --help. Other options might exist (see the SpiderMonkey script and the Stylo scripts to see how is it used inside the Servo organisation.

C++ Usage

This fork of rust-bindgen can handle a number of C++ features.

When passing in header files, the file will automatically be treated as C++ if it ends in .hpp. If it doesn't, -x c++ can be used to force C++ mode.

Annotations

The translation of classes, structs, enums, and typedefs can be adjusted using annotations. Annotations are specifically formatted html tags inside doxygen style comments.

opaque

The opaque annotation instructs bindgen to ignore all fields defined in a struct/class.

/// <div rustbindgen opaque></div>

hide

The hide annotation instructs bindgen to ignore the struct/class/field/enum completely.

/// <div rustbindgen hide></div>

replaces

The replaces annotation can be used to use a type as a replacement for other (presumably more complex) type. This is used in Stylo to generate bindings for structures that for multiple reasons are too complex for bindgen to understand.

For example, in a C++ header:

/**
 * <div rustbindgen replaces="nsTArray"></div>
 */
template<typename T>
class nsTArray_Simple {
  T* mBuffer;
public:
  // The existence of a destructor here prevents bindgen from deriving the Clone
  // trait via a simple memory copy.
  ~nsTArray_Simple() {};
};

That way, after code generation, the bindings for the nsTArray type are the ones that would be generated for nsTArray_Simple.

nocopy

The nocopy annotation is used to prevent bindgen to autoderive the Copy and Clone traits for a type.