php-in-php: JIT GcCollectCyclesNative — route gc_collect_cycles() through Vm CycleCollector PHP not phpc_gc.c LLVM (#1492)

[PurHur]

Category

php-in-php · runtime

Problem

gc_collect_cycles() VM uses lib/VM/CycleCollector.php via ext/standard/gc_collect_cycles.php, but JIT declares native entrypoints in lib/JIT/Builtin/GcCollectCyclesNative.php (__compiler_gc_collect_cycles, phpc_gc_* from C runtime). GC cycle semantics belong in PHP for self-host (#1492); C should remain a thin ABI for destructor hooks only.

Pairs #9150 (gc_status() php-in-php).

php-src reference

• php/php-src Zend/zend_gc.c — gc_collect_cycles()
• php/php-src ext/standard/info.c — PHP_FUNCTION(gc_collect_cycles) export

Repro

<?php
$a = new stdClass();
$b = new stdClass();
$a->r = $b;
$b->r = $a;
unset($a, $b);
echo gc_collect_cycles(), "\n";

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php repro_gc.php
php bin/jit.php repro_gc.php
'

Runtime	Prints collected count ≥ 0; no fatal
VM	yes
JIT	must match VM collector results on same graph

Scope

Layer	Path
VM SSOT	lib/VM/CycleCollector.php, ext/standard/gc_collect_cycles.php
JIT	ext/standard/JitGcCollectCycles.php — call PHP collector, not __compiler_gc_collect_cycles
Shrink	lib/JIT/Builtin/GcCollectCyclesNative.php declarations where replaceable
Tests	extend test/compliance/cases/runtime/gc_collect_cycles.phpt with JIT leg

PHP-in-PHP: shrink phpc_gc.c surface — document any remaining C-only destructor trampoline.

Done when (php-src-strict)

• Repro runs on JIT without native __compiler_gc_collect_cycles body
• VM/JIT collected counts agree on cyclic stdClass graph
• PR notes C symbols removed or gated
• ./script/ci-fast.sh --filter gc_collect_cycles green

Related

• php-in-php: JIT GcStatusRuntime — route gc_status() through VmGcStatus PHP not LLVM hashtable builder (#1492) #9150 gc_status php-in-php · Runtime: gc_collect_cycles() — run cyclic GC (Zend GC parity) #3113 GC subset · Stdlib JIT: gc_collect_cycles() LLVM lowering (phase 2 of #3113) #3160 native GC · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

claim: PHP Runtime → PHP — starting this run.

[PurHur]

Merged via #10066.

PHP path: ext/standard/GcCollectCyclesJitHelper.php + lib/JIT/Builtin/GcCollectCyclesCollectRuntime.php bridge
LLVM shrink: removed implementCollectCycles body from GcCollectCyclesRuntime.php (~57 lines); JitGcCollectCycles.php no longer pulls GcCollectCyclesNative

Verification: VM/JIT repro cyclic stdClass → 2; shrink + standalone + destruct + gc_status collect tests green; bootstrap inventory + spine sync OK.