pcbjam/wasm/shims/nanosleep_yield.c
Viktor Vaczi c1ef489cfa feat(wasm-eh): migrate the WASM build to native wasm exceptions (+ 3D viewer default-on)
Replace the legacy Emscripten JS-exceptions model with native wasm-EH (legacy
encoding) across the whole build, keeping Asyncify coroutines working via a
from-source Binaryen --hoist-cpp-catches pre-pass. Net result: native-EH is the
only build mode, the 3D viewer is on by default, and pcbnew shrinks substantially.

Highlights:
- Binaryen submodule everywhere + --hoist-cpp-catches integration in apply-asyncify;
  post-link Asyncify covers every app wasm (not just standalone test wasm).
- Build deps (incl. OpenCASCADE without OCC_CONVERT_SIGNALS) and all KiCad apps
  with -fwasm-exceptions; emscripten_sleep added to the post-link asyncify-imports.
- libcontext fiber entry wired under native exceptions; while-loop main loop +
  currData shim injected into all wx apps.
- Native-EH collab apply fixed: DEBUG-define the embind TU + match all out-of-CMake
  C++ TUs' ABI flags to the core, fixing the vtable-layout skew / mis-dispatch.
- 3D viewer enabled by default (real raytracer linked, not the stub).
- Retire the EH-spike scaffolding; flip the asyncify-races ablation pins to
  shim-redundancy pins (native-EH stays clean with the legacy shims ablated).
- Fix the asyncify-races quiescence check to not require Asyncify.currData==0:
  under the native-EH per-frame-yield top loop the main stack is asyncify-suspended
  every frame, so currData legitimately churns (a freed-but-not-yet-nulled buffer,
  not a leak). Refresh the pcbnew toolbar screenshot baseline for the new kicad.
- CI: drop the obsolete binaryen_version input/env (the build uses the binaryen
  submodule fork's wasm-opt, not a version download); key the wasm-output cache on
  the binaryen submodule SHA instead.

Bumps the wxwidgets + binaryen submodules to their squashed feature commits.

Validated green: all 7 apps native-EH (real 3D in pcbnew); KiCad e2e 63/63
Firefox + Chromium (3D viewer renders); wx 336; coroutine 34/34 both engines;
asyncify 7/7 both engines.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-06-30 09:40:26 +02:00

52 lines
2.5 KiB
C

/*
* nanosleep_yield.c — make a MAIN-THREAD nanosleep() YIELD to the JS event loop via
* Asyncify instead of busy-spinning, so on-demand pthread-Worker creation can complete
* WITHOUT editing KiCad.
*
* THE PROBLEM (the "non-warm thread" deadlock): once KiCad's thread pool has consumed all
* the pre-warmed Workers (-sPTHREAD_POOL_SIZE), a later raw std::thread (the raytracer)
* must spawn a NEW Worker on demand. Finalizing it needs the main thread's event loop to
* run the new-Worker 'loaded' -> 'run' handshake. KiCad's join is a sleep_for() busy-wait
* -> nanosleep -> emscripten_thread_sleep, which busy-spins and NEVER returns to the JS
* event loop, so the new Worker never starts -> deadlock.
*
* THE FIX: the only main-thread primitive that returns to the event loop is an Asyncify
* unwind (emscripten_sleep). This provides a nanosleep that, ON THE MAIN THREAD, yields via
* an EM_ASYNC_JS await (= emscripten_sleep semantics; __asyncjs__* is already in the
* post-link asyncify-imports). The unmodified sleep_for busy-wait then pumps the loop, the
* Worker handshake completes, and on-demand creation works with no KiCad edit.
*
* MECHANISM: a STRONG definition of nanosleep here SHADOWS musl's archive member — the
* linker only pulls musl's nanosleep.o if the symbol is left undefined, and ours defines it.
* (-Wl,--wrap=nanosleep is not an option here — it crashes wasm-ld with a SIGSEGV in
* lld::wasm::ImportSection::addImport.) On a pthread worker we fall back to
* emscripten_thread_sleep (the real underlying blocking sleep — workers may block).
*
* SCOPE: only the main browser thread yields; only it must never block the event loop.
*/
#include <emscripten/emscripten.h>
#include <emscripten/threading.h>
#include <time.h>
/* EM_ASYNC_JS integrates with Asyncify automatically (binaryen instruments every caller). */
EM_ASYNC_JS( void, __wasm_main_thread_yield_ms, ( double ms ), {
await new Promise( function( resolve ) { setTimeout( resolve, ms ); } );
} );
int nanosleep( const struct timespec* req, struct timespec* rem )
{
if( req )
{
double ms = (double) req->tv_sec * 1000.0 + (double) req->tv_nsec / 1.0e6;
if( emscripten_is_main_runtime_thread() )
__wasm_main_thread_yield_ms( ms ); /* yield -> event loop runs -> Worker boots */
else
emscripten_thread_sleep( ms ); /* worker: real blocking sleep */
}
if( rem )
{
rem->tv_sec = 0;
rem->tv_nsec = 0;
}
return 0;
}