Canonical LGPL-3.0-only text, GPL-3.0 companion, SPDX headers on all
first-party sources, MIT for examples/. Vendored lib/ untouched.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The browser wasm pipeline hardcoded -msimd128 for every wasm32 target and
baked a single wasm URL into index.html, so newer codegen features that
aren't yet baseline across engines (relaxed SIMD today; threads, future SIMD
revisions later) couldn't be adopted without dropping the browsers that lack
them.
Add a general, feature-parameterized mechanism owned entirely by
Crafter.Build:
- Configuration::wasmVariants declares N codegen variants (label, extra -m
flags, runtime probes). Build() compiles the baseline plus one
outputName.<label>.wasm per variant, recompiling the whole graph (incl.
dep libs + std PCM) with the variant's flags — relaxed-SIMD is per-TU
codegen, not a link switch. wasmVariantFlags folds into VariantId so each
variant's objects/PCMs land in their own build+bin dir.
- EnableWasiBrowserRuntime emits a variants.json manifest (label -> url +
probes), preferred-first with the baseline as the universal fallback.
- The shipped runtime.js runs inlined wasm-feature-detect probes
(relaxed-simd, simd, tail-call, bulk-memory, exception-handling, threads),
picks the first variant whose probes all pass, and falls back to the single
baked CRAFTER_WASM_URL when no manifest is present (backward compatible).
- EnableWasiRelaxedSimdVariant registers the relaxed-SIMD variant — the
motivating case (Chrome 114+/Firefox 120+ enable it by default; Safari
still flag-gates it as of mid-2026).
Verified end to end: a wasm32-wasip1 build emits both wasi-hello.wasm and
wasi-hello.relaxed-simd.wasm + variants.json; Firefox selects the
relaxed-simd variant and runs it.
Resolves#24
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
