Language: Enum::cases() — JIT/AOT case list lowering (phase 2 of #3308)

[PurHur]

Category

language

Problem (phase 2 of #3308)

UnitEnum::cases() / backed Enum::cases() work on VM via lib/VM/Builtin/EnumCases.php. JIT skips enum static calls (test/compliance/JITTest.php — "Enum::cases() is VM-only until JIT enum case lowering (#3308)").

Self-host and enum-heavy code needs compile-time/lowering of Suit::cases() without VM deopt.

php-src reference

• Zend/zend_enum.c — zend_enum_list_cases, case table materialization
• Zend/zend_compile.c — ZEND_FETCH_CLASS_CONSTANT for synthetic cases method

Repro (JIT failure today)

<?php
enum Suit: string { case Hearts = 'H'; case Spades = 'S'; }
$cases = Suit::cases();
echo count($cases), ':', $cases[0]->name, "\n";

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php repro.php'
./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/jit.php repro.php'

Zend / VM: 2:Hearts
JIT (today): VM fallback or compile skip for cases() static call.

Scope

• lib/JIT/ — lower TYPE_STATICCALL on enum classes where method is synthetic cases
• Reuse VM case list from VM\ClassEntry / enum registry at JIT compile time
• test/compliance/cases/language/enum_cases_jit.phpt (extend enum_cases.phpt)
• AOT: immortal array of case objects in module init (mirror Language: class const object expressions JIT/AOT — shared identity (phase 2 of #3196) #4021 class-const objects pattern)

Done when

• Repro prints 2:Hearts under bin/jit.php without VM fallback
• Unit enum (no backing type) and backed enum both covered
• JITTest enum-cases skip removed
• Syntax matrix: note Enum::cases() JIT yes

Links

• Language: UnitEnum::cases() / BackedEnum::cases() — list enum cases (PHP 8.1, Zend parity) #3308 (VM) · Language: enum_from() — BackedEnum::from / tryFrom (PHP 8.1) #3114 (from/tryFrom JIT) · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

claim: lane-c-worker — starting this run

[PurHur]

lane-c-worker — compile-time lowering landed in PR (not merged: MCJIT execute blocker).

Done

• Enum::cases() registers suit::cases LLVM that builds case object array from compile-time constants
• Enum case ->name / ->value in JIT property fetch
• test/unit/EnumCasesJitCompileTest.php — LLVM verify green

Verification

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php vendor/bin/phpunit test/unit/EnumCasesJitCompileTest.php'

Blocker (#3518)

MCJIT execute segfaults for any script with TYPE_DECLARE_ENUM (repro on master too). Compile succeeds; bin/jit.php / JITTest enum_cases fail at run. Next step: stabilize user-enum MCJIT execute, then unskip JITTest enum_cases and merge.