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WasmTarget.jl

A Julia-to-WebAssembly compiler targeting WasmGC.

Compile real Julia functions to WebAssembly that runs in any modern browser or Node.js. No runtime, no LLVM. Inspired by dart2wasm.

How It Works

Julia's compiler does the heavy lifting — parsing, macro expansion, type inference, optimization. WasmTarget gets the fully type-inferred IR via Base.code_typed() and translates it to WasmGC bytecode.

Julia source → Julia compiler (parse, lower, infer) → Typed IR → WasmTarget → .wasm

For functions with complex IR (GC internals, C library calls, deep dispatch), WasmTarget provides method overlays — the same pattern CUDA.jl uses.

Current Status

  • 176 core Julia functions compile and produce correct E2E results
  • 127 native (real Base IR), 48 overlay (pure Julia reimplementations), 1 blocked
  • 2409 tests, 0 fail, verified across Int32/Int64/UInt32/UInt64/Float32/Float64
  • Binaryen optimization: ~85% size reduction, zero regressions
  • Nested closures, deep compositions (8+ layers), 20-function modules verified
  • Powers Therapy.jl for build-time island compilation

Quick Example

using WasmTarget
bytes = compile(sin, (Float64,))
write("sin.wasm", bytes)

See Getting Started for installation and more examples.