php-in-php: JIT StringUnserialize — route unserialize() through VmUnserializeFormat PHP not __compiler_unserialize LLVM (#1492)

[PurHur]

Category

php-in-php · php-src-strict (runtime semantics from PHP VM path)

Problem

unserialize() VM lowering uses PHP (ext/standard/VmUnserializeFormat.php), but JIT/AOT still emit native __compiler_unserialize LLVM cloned from runtime/phpc_unserialize.c (lib/JIT/Builtin/StringUnserializeJit.php). This duplicates semantics in C, blocks self-host shrink, and risks VM/JIT drift on object refs, allowed_classes, and session decode paths.

php-src reference

• php/php-src ext/standard/var_unserializer.c — reference behavior
• This repo VM: ext/standard/VmUnserializeFormat.php, ext/standard/unserialize.php

Repro (JIT divergence probe)

<?php
$data = serialize(['a' => 1, 'b' => 2]);
echo unserialize($data)['b'], "\n";

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php repro.php
php bin/jit.php repro.php
# JIT must match VM; today JIT uses __compiler_unserialize C helper
'

Scope (this repo)

Layer	Work
JIT	Replace StringUnserializeJit C calls with call into compiled VmUnserializeFormat / shared PHP helper
AOT	Same entry as JIT
C shrink	Delete or bypass __compiler_unserialize / phpc_unserialize.c symbols when PHP path covers JIT builds
Tests	Extend test/compliance/cases/stdlib/unserialize*.phpt with JIT rows

Done when

• JIT/AOT unserialize() results match VM on compliance vectors (scalars, arrays, allowed_classes subset)
• No new runtime/*.c logic — note lines removed from C in PR body
• script/capability-matrix.php notes shared PHP lowering

Ref: #1492 · #5991 · #1175

[PurHur]

claim: PHP Runtime → PHP — starting this run.

[PurHur]

Merged via #10564.

What changed: Normal JIT/AOT modules now route unserialize() and phpc_session_decode_payload through compiled UnserializeJitHelper (delegates to VmUnserializeFormat). The ~1.2k-line StringUnserializeJit LLVM monolith is retained only for LOAD_TYPE_STANDALONE AOT link.

Verification (green on branch):

• vendor/bin/phpunit test/unit/JIT/StringUnserializeRuntimeStandaloneTest.php test/unit/VmUnserializeRuntimeShrinkTest.php — OK
• vendor/bin/phpunit --filter "stdlib/unserialize_jit" — OK (VM + JIT)
• vendor/bin/phpunit --filter "AotTest.*unserialize" — OK (standalone LLVM fallback)