php-in-php: delete StringVarExport NestedJit defer — thin via isThinStandaloneAotMain + JitVarExportKernel (#1492)

[PurHur]

Category

php-in-php · runtime-shrink (#1492, re-#19430 / #20065)

Problem

lib/JIT/Builtin/StringVarExport.php still gates the thin JitVarExportKernel path behind UserScriptAotDeferNestedJit::shouldDefer() (env PHP_COMPILER_AOT_USER_SCRIPT only). That leaves NestedJit on the audit surface and diverges from #20065 / #20050 / Rename shape where thin standalone AOT (user-script and bootstrap-aot-link) shares one Context::isThinStandaloneAotMain() gate.

Both paths already route through VarExportJitHelper PHP — this slice only retires the NestedJit defer gate.

php-src reference

• php/php-src ext/standard/var.c — php_var_export_ex

PHP implementation target

• lib/JIT/Builtin/StringVarExport.php — replace UserScriptAotDeferNestedJit::shouldDefer with $context->isThinStandaloneAotMain(); thin → JitVarExportKernel; embed/non-thin stays helper bridge
• test/unit/VarExportRuntimeShrinkTest.php — assert no UserScriptAotDeferNestedJit; assert isThinStandaloneAotMain

Repro

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
vendor/bin/phpunit test/unit/VarExportRuntimeShrinkTest.php
make bootstrap-selfhost-vm-driver-execute-probe
'

Done when

• UserScriptAotDeferNestedJit removed from StringVarExport.php
• Thin path gated by isThinStandaloneAotMain (php-in-php: delete StringHashCryptoJit NestedJit defer — thin via isThinStandaloneAotMain + real hash_equals (re-#20050) #20065 / Rename shape)
• Shrink test green
• make bootstrap-selfhost-vm-driver-execute-probe green
• PR body cites NestedJit defer call site removed

Refs #1492, #19430, #20065, #10533

[PurHur]

claim: PHP Runtime → PHP — starting this run.

Gates (pre-claim):

Gate	Result
make bootstrap-selfhost-link	OK /compiler/build/selfhost
php script/bootstrap-inventory.php --check	OK 5426/5426
check-selfhost-spine-coverage-sync	OK (covers all 5426)
./script/release-readiness.sh --json	in progress (north-star5-verify --fast); spine-coverage already ok this run

Plan: replace UserScriptAotDeferNestedJit::shouldDefer in StringVarExport with isThinStandaloneAotMain → JitVarExportKernel (#20065 shape); update shrink test; probe + merge.

[PurHur]

Merged via #20078

Verification:

• VarExportRuntimeShrinkTest OK (no NestedJit; isThinStandaloneAotMain)
• VarExportVMTest / VarExportJITTest OK
• bootstrap-selfhost-vm-driver-execute-probe OK

Shrink: removed 1× UserScriptAotDeferNestedJit call site from StringVarExport.php; thin path uses JitVarExportKernel for all isThinStandaloneAotMain() builds.