glCompileShader with MOBILEGL_ASYNC_SHADER_COMPILE=1 snapshots its inputs on
the GL thread (source SharedPtr, CompileEnv, cache handle) and runs the whole
pure pipeline - preprocess, validators, extractors, glslang parse - as a
ShaderCompileTask on the worker pool, returning immediately. Every read of
compile-produced state joins through the single Compiled() gate; links stay
synchronous this stage and join their attached shaders at the top of the
body. Flag off, the path is the same code run inline.
Mechanics: the job node owns all its inputs (no back-pointer, no lifetime
tie to the shader object), so re-sourcing or deleting a pending shader is
cancel-and-drop, never a wait; glslang worker hygiene is a TLS-allocator
scope guard plus GL-thread builtin prewarm (gated on the flag, latch reset
on Destroy so re-initialization re-warms); worker-side diagnostics defer
through the job and replay on the GL thread at the join, enforced by
IsPoolThread asserts in RecordError and an empty-deferred-errors tripwire.
A body that throws publishes a COMPLETE failed compile (status false, real
info log) rather than an abandoned node, and never memoizes away the retry;
a failed enqueue (OOM) cancels the node instead of stranding the joiner -
including inside the dispatch loop, where the in-flight slot is repaid.
The pool StopAndDrains from an atexit sentinel too: workers still inside
glslang parse while exit() ran static destructors was a real 2-in-5 SIGSEGV,
reproduced and fixed (15/15 clean after).
Backend-internal shader objects (default FS, DirectVulkan blit/mipmap) are
cache-less and always compile inline - compile-and-read-in-one-breath needs
no round trip.
Gates: unit suite 488/488 with the flag off AND on (x5); AsyncCompileTest
(12 e2e cases: pending re-source/delete/recompile, byte-identical failure
logs across modes, 48-compile cache stress) x10 repeats clean both modes;
full NVIDIA DirectGLES retrace identical result sets flag off/on (zero new
deltas); compile-phase timing flat as designed (links still serial - the
parallel win arrives with stage 4's async link + stage 5's
KHR_parallel_shader_compile).
Standalone Asio (submodule, asio-1-38-2 @ 8806a680, ASIO_STANDALONE +
ASIO_NO_DEPRECATED, header-only - no linked artifact) and the job machinery
the async shader pipeline will run on: JobNode (state machine with deferred
errors, continuations firing exactly once, dependency counters, cancel
semantics split into request vs outcome) and ShaderCompilePool
(asio::thread_pool behind a pimpl so no header leaks asio; big-core count
via cpufreq at >=85% of peak clamped to [1,4]; lazily constructed, so with
the flag off no worker thread ever exists; StopAndDrain leads DestroyImpl).
MOBILEGL_ASYNC_SHADER_COMPILE / _THREADS config knobs, default OFF. Nothing
in the GL pipeline references the pool yet - grep-verified; the full
DirectGLES retrace and compile benches are byte- and time-identical. 25
threaded unit tests, clean across 20x gtest_repeat.
- SpvcSession's move constructor and move assignment dropped the parsed
metadata, so a moved-to session silently reported empty reflection.
- ParseComputeLocalSize used std::stoull, whose std::out_of_range escaped
glCompileShader on an oversized local_size literal; now std::from_chars
saturating to UINT_MAX, pinned by a regression test that reproduced the
escaping exception.
- The compute local_size std::regex was rebuilt on every compile; hoisted.
- LinkProgram dumped every shader's full source through MGLOG_D per link.
- glslang::FinalizeProcess ran before the GL context tore down, leaving the
context's live TShaders pointing at freed builtin symbol tables.
MG_Config::FeaturesTable snapshots every MOBILEGL_* toggle once in
ConfigLoader::Init with a single truthy rule (non-empty, not '0', not
'false' case-insensitively), replacing 13 scattered std::getenv sites
that used four different parsing conventions. Renderer-derived bits
(IsAngleRenderer/IsAngleLlvmpipeRenderer/AvoidSamplerMipmapMinFilter)
move into GLESCapabilities, set once in FillInGLESCapabilities, so hot
paths (glMemoryBarrier ANGLE flush, sampler min-filter sync) stop doing
per-call string scans. MOBILEGL_PRESENT_DUMP_CALL/_CURRENT_CALL stay
live getenv (the retrace harness mutates them at runtime) and
MOBILEGL_LOG_FILE_PATH stays in Log.cpp (log init precedes config
init); both are documented in Config.h. Known semantic unification:
MOBILEGL_DISABLE_SUBGROUP previously required exactly 'true' and
MOBILEGL_PRESENT_STATS exactly '1'; both now follow the shared rule
(CI's 0/1 values parse identically). Also bumps CoreVersion to 26.07.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>