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scriptc/tests/corpus/webassembly-spec-float
Malte UblandClaude Opus 5.5 78184a9869 WebAssembly W3–W4: translate modules to native code at build time, the JavaScript API over them, and Module transfer to workers
A build now translates every WebAssembly module whose bytes it can see
(W2's discovery) into LLVM IR with a TypeScript translator
(packages/compiler/src/wasm/module.ts, translate.ts) and appends it to the
program module, so the existing LLVM helper optimizes, partitions and
caches it with the program. The program also emits scr_wasm_registry, a
portable table of module descriptors (scr_wasm_abi.h). At run time,
WebAssembly.compile, instantiate, validate, new Module and new Instance
find the translated module by the SHA-256 of its bytes; bytes the build did
not see reject with a CompileError. There is no interpreter and no JIT.

The runtime (scr_wasm.c, link-gated by the new `wasm` feature, handle tags
inside W0's headroom) implements the JavaScript API once, over
descriptors, with Node's semantics and messages: exports (functions,
memories, tables, globals), imports (functions, immutable globals, and
memories, tables and globals other instances export), every trap as
WebAssembly.RuntimeError, the CompileError, LinkError and RuntimeError
classes, compile and instantiate settling on a later turn, and
globalThis.WebAssembly as a value. On 64-bit Linux and macOS, memories sit
in 8 GiB guard reservations and a SIGSEGV/SIGBUS handler turns faults into
traps or stack exhaustion; async fibers get a guard page on first use.
Sanitizer builds and Windows check bounds and the stack explicitly. A
WebAssembly.Module crosses to workers through W0's transfer hook (W4).

W1's refusals become lowerings; the Memory, Table and Global constructors,
Module.imports/exports/customSections and the streaming functions still
refuse with SC2020. The globals: WebAssembly compatibility row moves to
partial.

Evidence: differential corpus programs for the API, TypeScript use and the
codemode worker shape, plus five programs executing about 9,300 commands
of the WebAssembly 2.0 spec suite; all match Node in the plain and
sanitized lanes. quickjs-wasi runs through its own glue, matching Node
(apart from a pre-existing non-wasm fence) and on par with or faster than
V8. The zero-cost gate leaves every non-wasm program byte-identical.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-19 05:33:11 -07:00
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