php-in-php: delete StringUnlink libc defer bridge — route user-script AOT through JitVmHelperLink + UnlinkJitHelper PHP (#1492)

[PurHur]

Category

php-in-php · runtime-shrink (#1492, re-#15471 / #16734)

Problem

lib/JIT/Builtin/StringUnlink.php still embeds ~35 lines of inline libc unlink(2) LLVM when UserScriptAotDeferNestedJit::shouldDefer() (#16734). Embed path already routes through UnlinkJitHelper → VmFs::unlink() (#15471). Prelinked helper-runtime provides UnlinkJitHelper::invokeArgv without nested-JIT during init — same pattern as #19157 EnvironMirror.

UnlinkRuntimeShrinkTest::testStringUnlinkBridgeUsesUnlinkJitHelper is red on master (asserts no lookupFunction('unlink')).

php-src reference

• php/php-src ext/standard/filestat.c — php_unlink

PHP implementation target

• lib/JIT/Builtin/StringUnlink.php — drop defer→libc branch; always JitVmHelperLink::ensureCompiled + bridge
• SSOT: ext/standard/UnlinkJitHelper.php + VmFs::unlink()

Repro

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php vendor/bin/phpunit --filter UnlinkRuntimeShrinkTest'
echo '<?php $f=tempnam(sys_get_temp_dir(),"u"); unlink($f); echo "ok\n";' > /tmp/unlink.php
PHP_COMPILER_AOT_USER_SCRIPT=1 php bin/compile.php -o /tmp/unlink_bin /tmp/unlink.php && /tmp/unlink_bin

Done when

• implementLibcBridge deleted (~35 lines libc LLVM removed)
• UnlinkRuntimeShrinkTest green
• User-script AOT unlink smoke green
• make bootstrap-selfhost-vm-driver-execute-probe green

Refs #1492, #15471, #16734, #19157

[PurHur]

claim: PHP Runtime → PHP — starting this run.

[PurHur]

Merged via #19196

Verification:

• php vendor/bin/phpunit --filter UnlinkRuntimeShrinkTest → OK (4 tests) — fixes red shrink test on master
• make bootstrap-selfhost-vm-driver-execute-probe → OK
• Net −58 lines in StringUnlink.php (libc defer LLVM deleted)

Follow-up: AotTest unlink fixture run still segfaults on master and branch (pre-existing); user-script AOT compile with unlink() still hits Current basic block has no parent function (#16734 class).