WebAssembly
Tools for working with the WebAssembly format in Julia. In particular, this package exposes the IR as simple Julia data structures, allowing parsers and code generators to convert to/from the IR, as well as allowing optimisation passes directly on the IR in the vein of binaryen.
Build IR for a x^n function:
using WebAssembly: i32, f64, irfunc
using IRTools.All
pow = let
ir = IR()
x = argument!(ir, f64)
n = argument!(ir, i32)
cond = block!(ir)
body = block!(ir)
ret = block!(ir)
n = argument!(cond, n, i32)
r = argument!(cond, 1.0, f64)
branch!(cond, ret, unless = push!(cond, stmt(xcall(i32.gt_s, n, Int32(0)), type = i32)))
n = push!(body, stmt(xcall(i32.sub, n, Int32(1)), type = i32))
r′ = push!(body, stmt(xcall(f64.mul, r, x), type = f64))
branch!(body, cond, n, r′)
return!(ret, r)
ir
endjulia> pow
1: (%1 :: f64, %2 :: i32)
br 2 (%2, 1.0)
2: (%3 :: i32, %4 :: f64)
%5 = (i32.gt_s)(%3, 0) :: i32
br 4 unless %5
3:
%6 = (i32.sub)(%3, 1) :: i32
%7 = (f64.mul)(%4, %1) :: f64
br 2 (%6, %7)
4:
return %4Construct a wasm function and module:
func = irfunc(:pow, pow)
mod = WebAssembly.Module(funcs=[func],
exports=[WebAssembly.Export(:pow, :pow, :func)])
WebAssembly.binary(mod, "test.wasm")Disassemble the result with binaryen:
shell> wasm-dis test.wasm
(module
(type $0 (func (param f64 i32) (result f64)))
(export "pow" (func $0))
(func $0 (; 0 ;) (type $0) (param $0 f64) (param $1 i32) (result f64)
(local $2 f64)
(local.set $2 (f64.const 1))
(loop $label$1
(if
(i32.eqz (i32.le_s (local.get $1) (i32.const 0)))
(block
(local.set $1
(i32.sub (local.get $1) (i32.const 1)))
(local.set $2
(f64.mul (local.get $2) (local.get $0)))
(br $label$1))))
(local.get $2)))(If wasm-dis is not on your path you can use
julia> run(`$(WebAssembly.Binaryen.wasm_dis) test.wasm`);to get syntax-highlighted WASM in a terminal).