php-in-php: JIT ScalarDimFetchHelper — route scalar dim fetch warnings through Vm PHP not LLVM (#1492)

[PurHur]

Category

php-in-php · php-src-strict · compile/runtime shared

Problem

lib/JIT/ScalarDimFetchHelper.php (~44 lines) emits inline LLVM that calls __compiler_trigger_error with hard-coded warning strings for ZEND_FETCH_DIM_R on scalar containers (int/float/string/bool/null). VM implements the same guard in PHP with shared message text (#4867).

Duplicated LLVM warning paths drift from php-src and block shrinking the JIT error layer toward compiled PHP helpers (#9778, #9679).

php-src reference

• php/php-src Zend/zend_execute.c — ZEND_FETCH_DIM_R on non-array/object → E_WARNING + null
• php/php-src Zend/zend_operators.c — type label in warning message

Repro (LLVM path today)

<?php
$x = 42;
var_export($x[0]);
echo "\n";

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php -r "\$x=42; var_export(\$x[0]); echo \"\\n\";" 2>&1 | head -3
php bin/vm.php -r "\$x=42; var_export(\$x[0]); echo \"\\n\";" 2>&1 | head -3
php bin/jit.php -r "\$x=42; var_export(\$x[0]); echo \"\\n\";" 2>&1 | head -5
wc -l lib/JIT/ScalarDimFetchHelper.php
'

Expected: Warning Trying to access array offset on value of type int + NULL on VM/JIT/AOT (php-src-strict).

Scope (this repo)

Shrink LLVM	Grow PHP
lib/JIT/ScalarDimFetchHelper.php emitArrayOffsetWarning() IR	Shared VM helper (e.g. extend lib/VM/ErrorReporter.php or dim-fetch module)
__compiler_trigger_error calls from dim fetch	Thin JIT trampoline calling compiled PHP warning+null helper
Call sites in lib/JIT.php scalar dim read lowering	VM/JIT/AOT message text SSOT

Do not grow runtime/*.c. Delete LLVM warning branches when PHP path is linked.

Done when

• Scalar dim fetch on int/float/string/bool/null uses compiled PHP helper on JIT and AOT standalone
• Warning message text matches Zend for representative types (php-src-strict)
• ScalarDimFetchHelper.php shrinks to thin trampoline; PR cites lines removed
• ./script/ci-fast.sh --filter ScalarDim or existing dim-fetch compliance subset green

Verification

make bootstrap-selfhost-vm-driver-execute-probe
./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && vendor/bin/phpunit --filter DimFetch'

Related

• Language: array offset on non-container types must emit E_WARNING (zend_execute.c) #4867 dim fetch semantics · php-in-php: JIT ErrorRaise + TypeErrorRaise — route catchable Error/TypeError through VmException PHP not ~920-line LLVM (#1492) #9778 error raise PHP path · North star Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492

[PurHur]

claim: PHP Runtime → PHP — starting this run (#10271 ScalarDimFetchHelper JIT → Vm PHP path)

[PurHur]

Merged via #10282

What changed: Scalar dim fetch JIT warnings now route through compiled ScalarDimFetchJitHelper PHP (ScalarDimFetchRuntime bridge) instead of inline LLVM __compiler_trigger_error in ScalarDimFetchHelper. Message SSOT: ErrorReporter::arrayOffsetOnNonContainerMessage().

Shrink: lib/JIT/ScalarDimFetchHelper.php 44 → 27 lines (removed emitArrayOffsetWarning() LLVM IR). No new runtime/*.c.

Verification: issue repro (VM/JIT warning + NULL on \$x[0] for int), phpunit --filter ScalarDimFetchJitHelperTest, phpunit --filter DimFetch|array_offset_scalar|dim_fetch_null (9 tests OK), make bootstrap-selfhost-vm-driver-execute-probe OK.