php-in-php: JIT StringPregMatchJit — route preg_* through VmPreg PHP not ~3k-line LLVM/pcre2 (#1492)

[PurHur]

Category

php-in-php · php-src-strict

Problem

preg_match(), preg_match_all(), preg_replace(), and friends have VM implementations in ext/standard/, but JIT/AOT emit ~3,000 lines of LLVM in lib/JIT/Builtin/StringPregMatchJit.php calling libpcre2-8 directly (mirrors deleted lib/AOT/runtime/preg_match.c). This duplicates offset capture, error codes, and PREG_* flag semantics — a frequent source of VM/JIT drift (#5289, #6639).

php-src reference

• php/php-src ext/pcre/php_pcre.c — php_pcre_match, error mapping
• php/php-src ext/standard/php_string.h — preg function exports
• VM: ext/standard/preg_match.php, VmPreg.php (or equivalent)

Repro

wc -l lib/JIT/Builtin/StringPregMatchJit.php
./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php test/compliance/cases/stdlib/preg_match_basic.phpt
php bin/jit.php test/compliance/cases/stdlib/preg_match_basic.phpt
php bin/jit.php -r "var_export(preg_match(\"/(\d+)/\", \"abc123\", \$m)); echo PHP_EOL, \$m[1];"
'

Symptom	VM	JIT today
Capture offsets / PREG_OFFSET_CAPTURE	PHP	Separate LLVM pcre2 path
preg_last_error() after JIT call	shared helper?	phpc_preg_last_error global

Scope

Layer	Files
PHP helper	New ext/standard/PregJitHelper.php wrapping VM preg engine
JIT	lib/JIT/Builtin/StringPregMatchJit.php → thin compile + call
FFI	Keep single pcre2 binding in PHP/VM layer; delete duplicate LLVM extern decls
Tests	Existing preg compliance PHPTs + enum-case subject guards (#3568 family)

Done when

• Representative preg PHPT suite green on JIT and AOT via PHP helper
• StringPregMatchJit.php ≤ thin wrapper; PR cites LLVM lines removed
• preg_last_error() consistent VM/JIT after failed match
• ./script/ci-fast.sh --filter preg_match green

Related

• php-in-php: preg_match() JIT — delete preg_match.c (~112 lines), lower from ext/standard/VmPreg.php #5289, php-in-php: preg_replace_callback()/preg_split() JIT — delete LLVM stubs, wire real lowering (ext/pcre/php_pcre.c) #6639 — preg JIT runtime origin
• php-in-php: JIT StringFormatJit — route sprintf/printf/number_format through VmSprintf not libc LLVM (#1492) #9131 — StringFormatJit php-in-php (parallel migration pattern)
• North star: Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

claim: PHP Runtime → PHP — batch (issues #9542)

[PurHur]

Merged via #12034.

LLVM shrink: StringPregMatchJit.php 3250→68 LOC (embed dispatcher); pcre2 monolith quarantined to StringPregMatchStandaloneLlvm.php. SSOT: ext/standard/PregJitHelper.php → VmPregNative.

Verification: PregMatchRuntimeShrinkTest + preg JIT compliance (match/last_error/replace/split) green; spine sync + bootstrap-selfhost-vm-driver-execute-probe OK.