Haskell WebAssembly

A portable machine architecture for the web.

Define a portable, size- and load-time-efficient binary format to serve as a compilation target which can be compiled to execute at native speed by taking advantage of common hardware capabilities available on a wide range of platforms, including mobile and IoT.

• Design
• Semantics
• Reference Implementation
• Binary Encoding
• ilwasm
• binaryren
• wassembler
• demo
• backend prototype
• WasmExplorer
• Javascript API

Binary Protocol

• wasm.h
• wasm-binary.h

Chrome

• v8 wasm

As of Chrome 56 the flag #enable-webassembly can be enabled to add support for WebAssembly.

Firefox

• BaldrMonkey: land initial wasm compilation and testing functions

Goals

• Parse WebAssembly textual AST
• Read binary format
• Emit binary format
• Pretty print textual AST
• Verify soundness of code
• Interpreter
• High level code generation API for retargeting
• Translation to LLVM IR backend

Build with stack (recommended)

$ git clone https://github.com/sdiehl/wasm
$ cd wasm
$ stack install

$ wasm test/fac.wast

Build with cabal

$ git clone https://github.com/sdiehl/wasm
$ cd wasm

$ cabal sandbox init
$ cabal install

How to Run Test Suite

$ stack test

How to Run inside GHCi

$ stack ghci wasm

Building v8

In Chrome:

WebAssembly.compile(new Uint8Array(
 `00 61 73 6d  0d 00 00 00  01 09 02 60  00 00 60 01
7f 01 7f 03  03 02 00 01  05 04 01 00  80 01 07 07
01 03 66 6f  6f 00 01 08  01 00 0a 3a  02 02 00 0b
35 01 01 7f  20 00 41 04  6c 21 01 03  40 01 01 01
0b 03 7f 41  01 0b 20 01  41 e4 00 6c  41 cd 02 20
01 1b 21 01  41 00 20 01  36 02 00 41  00 21 01 41
00 28 02 00  0f 0b 0b 0e  01 00 41 00  0b 08 00 00
00 00 2c 00  00 00`.split(/[\s\r\n]+/g).map(v => parseInt(v, 16))
)).then(mod => {
 let m = new WebAssembly.Instance(mod)
 console.log('foo(1) =>', m.exports.foo(1))
 console.log('foo(2) =>', m.exports.foo(2))
 console.log('foo(3) =>', m.exports.foo(3))
})

In V8:

$ git clone [email protected]:v8/v8.git
$ make native wasm=on

$ out/native/v8 --expose-wasm
V8 version 4.9.0 (candidate)
d8> buffer = readbuffer('test.bin');
[object ArrayBufferr
d8> module = WASM.instantiateModule(buffer, {});
{memory: [object ArrayBuffer], test: function test() { [native code] }}
d8> module.test()
3

Codebase

Core modules

• Entry - Driver
• Syntax - Frontend AST
• Eval - Interpreter
• Parser - Parser
• Lexer - Lexer
• Pretty - Pretty Printer
• Test - Test suite

Example

(module

  ;; Recursive factorial
  (func (param i64) (result i64)
    (if_else (i64.eq (get_local 0) (i64.const 0))
      (i64.const 1)
      (i64.mul (get_local 0) (call 0 (i64.sub (get_local 0) (i64.const 1))))
    )
  )

)

(module
  (export "test" 0)
  (func (result i32)
    (i32.add (i32.const 1) (i32.const 2))))

Will generate

0000000 0101 0100 0102 0009 1500 0000 0500 4000
0000010 0109 0209 7406 7365 0074               
000001a