wasm builds were compiled with -fno-exceptions. A throw did not
compile, libc++'s own throws (vector::at, std::format, filesystem)
aborted the program, and code that relies on exceptions could not be
built for the browser at all.
Every wasm unit and the std module now get -fwasm-exceptions, and the
link adds -lunwind, which code built that way calls into and the driver
does not add. The flag also selects the libc++ under the sysroot's
lib/<triple>/eh, which wasi-sdk 33 and later ship next to the noeh
one. Those libraries use the standardized encoding (try_table, exnref)
while LLVM 23 still emits the legacy one by default, which wasmtime
refuses to load and which would put both in one binary, so the flags
ask for the standard form with -wasm-use-legacy-eh=false. That makes
the setjmp lowering loadable under wasmtime too.
The flags live in one constant, WasmBaselineFlags, which the compile
command and the std module both take through WasmCompileFlags: a BMI
is refused by a unit whose exception setting differs from its own.
VariantId and StdPcmDir hash it, so the first build after the update
starts fresh instead of importing PCMs built without exceptions, and
two releases sharing the Flatpak's cache don't take turns rebuilding
one std PCM. A sysroot without the exception-enabled libraries stops
the build with a line saying so, rather than at the link with "unable
to find library -lunwind".
The result needs an engine with exnref: Chrome 137, Firefox 131,
Safari 18.4, the bundled wasmtime. The runtime's exception-handling
probe tested the legacy encoding; it now tests try_table, every
variants.json entry carries it, and a browser without it is told which
feature it lacks instead of failing with a CompileError. There is no
switch back to -fno-exceptions: engines without exnref are old enough
not to keep a second build for them.
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>
The random_get import was stubbed to return success without writing any
bytes, so every std::random_device user in wasm got all-zero
"randomness". This collided WebRTC peer ids across browser tabs in
3DForts (Catcrafts/3DForts#50).
Fill the target buffer from crypto.getRandomValues (a CSPRNG), chunking
at 65536 bytes to stay under WebCrypto's per-call quota, and add
random_get to the bind list since it now touches this.instance.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
WASI / wasm32 target support
- Auto-detect /usr/share/wasi-sysroot on Linux when target starts_with("wasm32")
- Skip -march/-mtune for wasm (clang rejects them)
- Apply -fno-exceptions -fno-c++-static-destructors -mllvm -wasm-enable-sjlj
-D_WASI_EMULATED_SIGNAL to wasm builds (compile + std PCM, kept in sync)
- .wasm output extension in expectedOutputFor and link command
- EnableWasiBrowserRuntime(cfg): opt-in helper that drops index.html +
runtime.js next to the .wasm; runtime.js reads window.CRAFTER_WASM_URL
set in the templated index.html so a single shim handles any output name
-r run flag in the CLI: build then exec the artifact (host targets only;
rejects libraries; auto .exe/.wasm extension handling)
CI pipeline (.forgejo/workflows/ci.yaml)
- Triggers: PR/push to master + manual dispatch
- Single arch-latest container job: install deps, bootstrap, self-rebuild,
run tests, cross-compile mingw, package both archives, upload artifacts
- Rolling 'latest' release published only on push/dispatch to master
mingw cross-compile from Linux now works end-to-end:
- ExternalDependency cache key includes target so per-target glslang builds
don't collide; CMAKE_BUILD_TYPE=Release pinned (otherwise glslang appends
'd' to lib names and breaks linking); cross-compile cmake flags
(CMAKE_SYSTEM_NAME=Windows, CMAKE_*_COMPILER_TARGET=...)
- project.cpp accepts --target=<triple>; Linux-only -Wl,--export-dynamic
and -ldl are gated; mingw glslang skips the standalone exe (its libgcc_eh
link pulls pthread which mingw doesn't link by default)
- mingw compile uses -femulated-tls so std::__once_callable etc reference
the same emutls symbols libstdc++ provides
- mingw link auto-adds -lstdc++exp -lpthread
GetCrafterBuildHome() exposed from the Platform module; LoadProject (Linux
+ Windows) now both use it instead of duplicating the resolution.
Examples reorg: hello-world, library, with-module, wasi, tests — each with
its own README. Tests reorg: per-test directory with inner/ fixture, no
shared tests/fixtures/ tree. New Wasi test verifies .wasm magic bytes.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
