php-in-php: JIT ArrayAccessHelper — route ArrayAccess $obj[$k] LLVM through VmArrayAccess PHP not ~301-line monolith (#1492)

[PurHur]

Category

php-in-php · language

Problem

ArrayAccess offset syntax $obj[$key] (read/write) lowers through lib/JIT/ArrayAccessHelper.php (~301 LOC) with LLVM interface checks and indirect offsetGet/offsetSet calls. VM dispatches via PHP (lib/VM.php + user methods).

Duplicated logic risks drift vs php-src read_dimension / write_dimension on objects implementing ArrayAccess (#3331, #4012).

php-src reference

• php/php-src Zend/zend_execute.c — ZEND_FETCH_OBJ_R, ArrayAccess dimension handlers
• php/php-src Zend/zend_interfaces.c — zend_call_known_instance_method for offsetGet/offsetSet

Repro

wc -l lib/JIT/ArrayAccessHelper.php
./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/jit.php -r "
class C implements ArrayAccess {
  private array \$d = [];
  public function offsetExists(\$k): bool { return isset(\$this->d[\$k]); }
  public function offsetGet(\$k): mixed { return \$this->d[\$k]; }
  public function offsetSet(\$k, \$v): void { \$this->d[\$k] = \$v; }
  public function offsetUnset(\$k): void { unset(\$this->d[\$k]); }
}
\$c = new C(); \$c[\"x\"] = 1; echo \$c[\"x\"];
" 2>&1
'

Scope (PHP-in-PHP)

Path	Work
lib/JIT/ArrayAccessHelper.php	Replace LLVM monolith with VmArrayAccess trampoline
lib/VM/ArrayAccessDispatch.php (new or existing)	SSOT for offsetGet/Set/Exists/Unset
lib/JIT/Call/RuntimeIndirectInstanceMethodCall.php	Reuse where possible

Done when

• JIT ArrayAccess read/write on repro class matches VM
• ArrayAccessHelper.php ≤ ~50 LOC glue; monolithic LLVM removed
• ./script/ci-fast.sh --filter ArrayAccess green (add JIT smoke if missing)

Related

• Language: ArrayAccess interface — $obj[$key] offset dispatch on user objects (Zend object handlers parity) #3331 · Language: ArrayAccess — JIT/AOT offset dispatch on user objects (phase 2 of #3331) #4012 · Stdlib: ArrayObject::__construct() missing — parent::__construct and new ArrayObject($array) fatal (ext/spl/spl_array.c) #10169 ArrayObject · Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

claim: PHP Runtime → PHP — batch (issues #10246 ArrayAccessHelper, #10240 IteratorProtocolHelper)

[PurHur]

Merged via #11610.

JIT shrink: ArrayAccessHelper.php 301→76 lines (trampoline); SSOT moved to lib/VM/VmArrayAccess.php (308 lines).

Verification:

OK (2 tests) ArrayAccessHelperRuntimeShrinkTest
OK (3 tests, 1 skipped) ArrayAccessJITTest filter
check-selfhost-spine-coverage-sync: OK