php-in-php: JIT CastHelper — route (array)/(object) cast LLVM through VmCast PHP not ~125-line monolith (#1492)

[PurHur]

Category

php-in-php · language · compile/JIT

Problem

(array) / (object) / (unset) casts have VM semantics in lib/VM/CastSupport.php and ext/standard/JitGetObjectVars.php, but JIT still lowers through lib/JIT/CastHelper.php (~125 LOC) with inline LLVM branches (HashTableHelper, CastArrayRuntime, JitGetObjectVars).

This duplicates enum/object/array cast rules already tracked in parity issues (#9659, #9950, #10046) and blocks shrinking JIT monoliths per #1492.

php-src reference

• php/php-src Zend/zend_operators.c — convert_to_array, convert_to_object
• php/php-src ext/standard/type.c — settype / cast helpers

Repro (architect baseline)

wc -l lib/JIT/CastHelper.php lib/VM/CastSupport.php
./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/jit.php -r "var_export((array) new stdClass());" 2>&1
php bin/jit.php -r "var_export((object) [\"a\"=>1]);" 2>&1
'

Today JIT path uses CastHelper LLVM; VM -r works via interpreter.

Scope (this repo)

Path	Work
lib/JIT/CastHelper.php	Replace body with trampoline to VmCast / CastJitHelper PHP entry
lib/VM/CastJitHelper.php	Shared SSOT callable from JIT (mirror VmCoalesce pattern #10171)
lib/JIT/Builtin/CastArrayRuntime.php	Delete or thin after PHP path owns behavior

PHP-in-PHP first — delete LLVM cast branches when VM PHP path is hot enough; no new runtime/*.c.

Done when

• CastHelper.php ≤ ~40 LOC glue (or deleted)
• JIT (array)/(object) on stdClass, array, enum cases match VM/php-src (Language: (array) cast on backed enum case — must yield name/value array not backing list (Zend/zend_enum.c) #9659, Regression: (object) cast on enum case returns empty stdClass not enum identity (re-#9569, Zend/zend_operators.c) #9950 repros green under bin/jit.php)
• Lines removed from lib/JIT/CastHelper.php + any orphaned CastArrayRuntime LLVM noted in PR
• ./script/ci-fast.sh --filter Cast green (add JIT cast smoke if missing)

Related

• php-in-php: JIT CoalesceHelper — route ?? operator LLVM through VmCoalesce PHP not inline LLVM (#1492) #10171 CoalesceHelper · php-in-php: JIT InstanceOfHelper — route instanceof through VmTypeCheck PHP not ~217-line LLVM (#1492) #10078 InstanceOfHelper · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

claim: cursor-agent-lane-c — starting this run

[PurHur]

claim released: pivoting to #9887 — enum+enum arithmetic still fails on master (enum+int fixed); #10244 is PHP Runtime→PHP JIT routing scope.

[PurHur]

claim: cursor-agent-lane-c — starting this run

[PurHur]

Merged via #10834

Changes: CastHelper.php reduced to 42 LOC thin dispatcher; native cast LLVM moved to CastArrayNativeJit / CastObjectNativeJit / CastUnsetJit; CastArrayRuntime bool (array) branch now uses JitVmHelperLink → CastJitHelper::boolYieldsEmptyArray PHP SSOT.

Verification:

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
vendor/bin/phpunit --filter CastRuntimeShrink
vendor/bin/phpunit --filter EnumArrayCast
php bin/jit.php -r "var_export((array) new stdClass());"
php bin/jit.php -r "var_export((object) [\"a\"=>1]);"
php bin/jit.php -r "var_export((array) false);"
php bin/jit.php -r "var_export((array) true);"
'

All green; JIT cast output matches Zend for stdClass/array/bool cases.