Engines and platforms

wazy.NewRuntime(ctx) picks the optimizing compiler on amd64 and arm64 and falls back to the interpreter everywhere else. Force either explicitly:

r := wazy.NewRuntimeWithConfig(ctx, wazy.NewRuntimeConfigInterpreter())
r := wazy.NewRuntimeWithConfig(ctx, wazy.NewRuntimeConfigCompiler())

The compiler translates each module to machine code during CompileModule — 4x to 45x faster than the interpreter across the go-anydoc runs. The interpreter has no architecture-specific code, so it runs anywhere Go does, including js/wasm and wasip1/wasm.

CI coverage

Full suite + spec corpora, every commit	linux/amd64, windows/amd64, darwin/arm64, on two Go versions, plus a -race -short run and four fuzz targets — three differential against the interpreter, one for validation.
Test binaries run, every commit	linux/arm64 and linux/amd64 in a scratch container (one variant with PROT_EXEC denied); FreeBSD, OpenBSD, NetBSD, DragonFly and illumos on amd64. The scratch runs exclude the spectest packages; the BSD and illumos runs also exclude imports/**, sysfs and the generated 3.0 corpus.
Cross-compiled every commit	plan9, js/wasm, wasip1/wasm, aix/ppc64, linux/{s390x,ppc64le,arm,386}, freebsd/amd64 — they build and run the interpreter; CI does not execute their suites. riscv64 runs locally under qemu-riscv64-static, because the hosted runner never completes.

If you depend on a target in the lower rows, open an issue and ask for CI coverage.

32-bit hosts

Linear memory tops out just under 2 GiB rather than the 4 GiB a 32-bit Wasm memory may declare, bound by what a Go slice holds. A module asking for more is rejected, which the specification allows.

PROT_EXEC-denied environments

The compiler needs to map executable pages. Where that is denied — some hardened containers — the interpreter is the fallback, and CI runs a scratch variant with PROT_EXEC denied to keep that path honest.

Wasm feature levels

wazy.NewRuntimeConfig().WithCoreFeatures(api.CoreFeaturesV3)

api.CoreFeaturesV2 is the default. api.CoreFeaturesV3 turns on all eight proposals Wasm 3.0 folded in: tail calls, extended const, exception handling, typed function references, relaxed SIMD, multiple memories, memory64 and garbage collection. Individual features can be composed with the api.CoreFeature* bits, and experimental.CoreFeaturesThreads adds shared memory and atomics.