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Gen-1+ #1492: Zend gen-0 compiler_minimal SIGSEGV after c:include M3EmitTuTrivialEchoAot.php (unblocked by #21888) #21925
Description
Category
Gen-1+ #1492 · Pillar 1 trust · Zend gen-0 AOT of compiler_minimal (re-#21888)
Problem
After #21888 removes the NestedJIT SuperglobalRefreshJitHelper::buildGetTable(): HashTable, int returned TypeError, make bootstrap-selfhost-link Zend gen-0 fallback proceeds ~11–13 min then dies:
phpc: fatal signal (segfault) after c:include:/compiler/lib/JIT/M3EmitTuTrivialEchoAot.php
make: *** [Makefile:298: bootstrap-selfhost-link] Error 139
PHP_COMPILER_LLVM_ASSERT=1 does not convert this into a PHP exception (hard SEGV in host php bin/compile.php / LLVM FFI).
Classification (not introduced by kernel-only refresh)
On PR #21904 tip, reproduced both:
- Kernel-only
__superglobals__refresh(JitSuperglobalRefreshKernel) → TypeError gone → same M3EmitTu SEGV - ClassReturnCheck-only (NestedJIT
SuperglobalRefreshRuntimerestored from master + HashTable ABI accept inClassReturnCheck) → TypeError gone → same M3EmitTu SEGV
So the crash is latent once Zend gen-0 gets past the #21888 TypeError; unrelated to retiring the NestedJIT refresh bridge.
| Gate | Result |
|---|---|
| #21888 TypeError | fixed on #21904 |
BOOTSTRAP_GEN0_ZEND_ONLY=1 make bootstrap-selfhost-link |
red — this SEGV |
PHP implementation target
- Lowering around include of
lib/JIT/M3EmitTuTrivialEchoAot.phpduringtest/selfhost/compiler_minimal/main.phpAOT - Breadcrumb:
build/.last-jit-func/ SIGSEGV handler inext/standard/JitProgressNoteKernel.php - Debug:
PHP_COMPILER_LLVM_ASSERT=1, gdb onphp bin/compile.php -o build/selfhost test/selfhost/compiler_minimal/main.php - No new
runtime/*.c
Repro
./script/docker-exec.sh -- bash -lc 'BOOTSTRAP_GEN0_ZEND_ONLY=1 make bootstrap-selfhost-link'(Requires #21888 / PR #21904 or equivalent so compile is not aborted earlier by HashTable TypeError.)
Done when
- Zend gen-0
compiler_minimalAOT completes without SEGV atM3EmitTuTrivialEchoAot.php -
make bootstrap-selfhost-linkgreen withoutBOOTSTRAP_ALLOW_STALE_COMPILED_DRIVER=1 - php-src-strict N/A (bootstrap/codegen); no new C runtime logic
Activity
PurHur commentedon Jul 21, 2026
claim: Lane B implementer — starting this run
Pre-claim gates (host): docker info OK; bootstrap-selfhost-link in progress (expecting this SEGV at M3EmitTuTrivialEchoAot.php).
Will branch
agent/issue-21925-m3emit-tu-segvand debug Zend gen-0 AOT crash.PurHur commentedon Jul 21, 2026
claim: lane-B compile/link automation — starting this run
TRY_FIRST (this workspace):
BOOTSTRAP_GEN0_ZEND_ONLY=1 make bootstrap-selfhost-linkSEGV after M3EmitTuTrivialEchoAot.phpPurHur commentedon Jul 21, 2026
yield: earlier claim at 19:27:35 UTC beat this run by ~13s — stepping off #21925 to avoid duplicate work. Good luck on the M3EmitTu SEGV.
Fix Zend gen-0 selfhost link abort after successful AOT emit (#21925) (…
PurHur commentedon Jul 21, 2026
Merged #21936
Verification
BOOTSTRAP_GEN0_ZEND_ONLY=1 make bootstrap-selfhost-link→OK/LINK_EXIT:0(host no longer dies withfree(): invalid pointerafter emit)vendor/bin/phpunit --filter SelfhostAotFastExitTest→ OK (3 tests)Fix
bin/compile.php:_exit(0)after successfultest/selfhost/AOT emit (skip LLVM FFI teardown abort)Builder::disposepatchBOOTSTRAP_SELFHOST_RUN_TRIES, default 5) for residual ~15–25% binary teardown flakeResidual heap corruption in fresh Zend
build/selfhostteardown still worth a follow-up if it stays noisy.Foundation: fast-exit selfhost AOT before LLVM context teardown (#31726…