php-in-php: drop always-on LibcExtern/Module stat+access+lstat after JitStatKernel (#30530/#31374 shape)

[PurHur]

Category

php-in-php · runtime-shrink (#1492, peer #30530 / #31374)

Problem

User-script file_exists / is_* / stat paths already route through StatPathJitHelper + JitStatPathKernel / JitStatKernel (#23297 / #27013). Always-on LibcExtern + Module::jitInit still register libc stat/access/lstat for every compile — same dead always-on surface #31374 removed for chmod/mkdir and #30530 removed for unlink/realpath/….

Path	Today	Target
User-script AOT path predicates / fields	PHP helpers + JitStatKernel (already)	unchanged
LibcExtern	always-on stat/access/lstat	drop rows
Module::jitInit	always-on try/add	drop; comment #30530/#31374 peer
NestedJIT JitStatKernel	lookupFunction relies on always-on	module-local ensureLibcStat
TouchLibcRuntime / FtokRuntime / JitFsGlobKernel	lookup assumes always-on	ensure module-locally (Ftok already has ensureLibcStat)

php-src reference

• php/php-src ext/standard/filestat.c — php_stat / php_access (semantics stay in PHP helpers; libc is thin ABI only)

PHP implementation target

• lib/JIT/LibcExtern.php — drop stat/access/lstat rows; cite this issue
• ext/standard/Module.php — drop always-on decls
• ext/standard/JitStatKernel.php — ensureLibcStat before mode/access/longField
• lib/JIT/Builtin/TouchLibcRuntime.php / FtokRuntime.php / ext/standard/JitFsGlobKernel.php — ensure before lookup
• test/unit/LibcExternDeadDeclsRuntimeShrinkTest.php, ModuleAlwaysOnFsDeclsRuntimeShrinkTest.php, StatPathRuntimeShrinkTest.php

Repro / verify

./script/phpunit.sh --filter 'LibcExternDeadDeclsRuntimeShrinkTest|ModuleAlwaysOnFsDeclsRuntimeShrinkTest|StatPathRuntimeShrinkTest|FtokRuntimeShrinkTest|TouchRuntimeShrinkTest'
./script/docker-exec.sh -- bash -lc 'php bin/vm.php -r "var_export(file_exists(__FILE__));"'

Done when

• LibcExtern / Module no longer always-declare stat/access/lstat
• NestedJIT consumers declare module-locally; shrink unit tests green
• php-src-strict; no php-compiler-strict shortcut
• Net shrink: always-on libc FS surface reduced (no new C)

Refs #1492, #30530, #31374, #23297, #27013

[PurHur]

claim: PHP Runtime → PHP — starting this run — drop always-on LibcExtern/Module stat+access+lstat; NestedJIT consumers already (or will) ensure module-locally (#30530/#31374 shape).

[PurHur]

Merged via #31405

Verification

• ./script/phpunit.sh --filter 'LibcExternDeadDeclsRuntimeShrinkTest|ModuleAlwaysOnFsDeclsRuntimeShrinkTest|StatPathRuntimeShrinkTest' → OK (18 / 220)
• related Ftok/Touch/FsGlob/SysGetTempDir shrink → OK (21)
• file_exists/is_file VM repro → true/true/false

Net shrink

• Dropped always-on stat/access/lstat from LibcExtern + Module::jitInit
• Module-local ensure in JitStatKernel / JitFsGlobKernel (Touch/Ftok already had ensures)