Binaryen.ml

OCaml bindings for Binaryen.

Binaryen is a compiler and toolchain infrastructure for WebAssembly. It makes compilation to WebAssembly pretty darn easy.

Here's Binaryen's hello world test in OCaml form:

openBinaryenlet wasm_mod =Module.create ()(* Create function type for i32 (i32, i32) *)let params =Type.create [| Type.int32; Type.int32 |]
let results =Type.int32(* Get arguments 0 and 1, add them *)let x =Expression.Local_get.make wasm_mod 0Type.int32let y =Expression.Local_get.make wasm_mod 1Type.int32let add =Expression.Binary.make wasm_mod Op.add_int32 x y
(* Create the add function *)(* Note: no additional local variables *)let adder =Function.add_function wasm_mod "adder" params results [||] add
let _ =Module.print wasm_mod
let _ =Module.dispose wasm_mod

Feature Parity

This project aims to provide full feature parity with the Binaryen C API. It's fairly complete, but a few things still need bindings:

• SIMD instructions
• Tags
• Atomics
• Query operations on expressions
• Query operations on functions

None of these are particularly challenging to create bindings for—they just haven't been written yet. If you need anything that's missing, feel free to open a PR.

MacOS C++ Compiler

When including this library in your dune MacOS executables, you'll need to specify -cc clang++ in your (ocamlopt_flags) stanza. This is required because Binaryen will throw errors for itself to catch and using clang++ is the only way to handle them correctly. You can find more info on this ocaml issue.

Your stanza could look something like this:

 (executable
(name example)
(public_name example)
(package example)
+ (ocamlopt_flags -cc clang++)
(modules example)
(libraries binaryen))

These flags likely won't work on other operating systems, so you'll probably need to use dune-configurator to vary the flags per platform. You can see an example of this in our test/.

Static Linking

If you are planning to create portable binaries for Windows, it will try to find Cygwin/MinGW locations in your PATH. To avoid this, you probably want to add this to your (executable) stanzas:

 (executable
(name example)
(public_name example)
(package example)
+ (flags (:standard -ccopt -- -ccopt -static))
(modules example)
(libraries binaryen))

These flags might not work on other operating systems (like MacOS), so you'll probably need to use dune-configurator to vary the flags per platform.

Contributing

You'll need Node.js and esy to build this project.

dune will take care of compiling the C stubs, so to build the project you'll only need to run:

esy

This will take a while. Once it's done, you can run the tests:

esy test