WasmExceptions builds a fixture for wasm32-wasip1 and runs it under
wasmtime. It throws through four frames whose destructors have to run,
catches the exception, catches one that vector::at throws, and with an
argument lets one escape main, which has to fail the run. With the
previous flags the fixture does not compile ("cannot use 'throw' with
exceptions disabled"), and each part of turning exceptions on fails it
in its own way, from a BMI built without them to the legacy encoding
wasmtime refuses.
WasiSysrootWithoutExceptions takes a scratch sysroot through three
states, no libunwind, libunwind under eh/ and libunwind in the
triple's own directory, and checks that only the first stops the
build, with the message naming the library it looked for. It needs no
working wasm toolchain, so it also runs where the others skip.
WasmHelloRuns and WasmExceptions treat a sysroot without the
exception-enabled libraries as missing and skip. The manifest tests
expect the exception-handling probe on every entry.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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>
