@grain/binaryen.ml NPM

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:

open Binaryen

let 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 0 Type.int32
let y = Expression.Local_get.make wasm_mod 1 Type.int32
let 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 tests/.

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.