php-in-php: delete EnvironMirrorRuntimeUserScriptCstr — route defer through HelperRuntimeCache + EnvironMirrorNativeJitHelper PHP (#1492)

[PurHur]

Category

php-in-php · runtime-shrink (#1492)

Problem

lib/JIT/Builtin/EnvironMirrorRuntimeUserScriptCstr.php (~182 LOC) hand-lowers a libc environ walk for user-script AOT when UserScriptAotDeferNestedJit is active (#15417, #18984). #19006 / helper-runtime cache (PHP_COMPILER_HELPER_RUNTIME_O=1 in bin/compile.php) now prelinks EnvironMirrorNativeJitHelper without nested-JIT during init — same pattern that made ProcessExecCaptureNativeJitHelper AOT-safe.

php-src reference

• php/php-src sapi/cli/php_cli.c — copy environ into superglobals on CLI startup

PHP implementation target

• lib/JIT/Builtin/EnvironMirrorRuntime.php — drop defer→UserScriptCstr branch; always JitVmHelperLink + EnvironMirrorNativeJitHelper
• Delete lib/JIT/Builtin/EnvironMirrorRuntimeUserScriptCstr.php
• SSOT: ext/standard/EnvironMirrorNativeJitHelper.php + VmEnvEnvironNative::enumerate()

Repro

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php vendor/bin/phpunit test/unit/EnvironMirrorRuntimeShrinkTest.php'
echo '<?php echo getenv("PATH") !== false ? "ok" : "fail";' > /tmp/env.php
PHP_COMPILER_AOT_USER_SCRIPT=1 php bin/compile.php -o /tmp/env_bin /tmp/env.php && /tmp/env_bin

Done when

• EnvironMirrorRuntimeUserScriptCstr.php deleted (~182 LLVM/libc lines)
• EnvironMirrorRuntimeShrinkTest updated
• User-script AOT smoke green; make bootstrap-selfhost-vm-driver-execute-probe green

Refs #1492, #18984, #15417, #19006

[PurHur]

claim: PHP Runtime → PHP — starting this run.

[PurHur]

Blocker (this run)

Removing the UserScriptAotDeferNestedJit → EnvironMirrorRuntimeUserScriptCstr defer branch and routing all paths through JitVmHelperLink + prelinked helper-runtime reproduces the same standalone AOT init failure as #19149 / ObOutputExecCapture:

source script/php-env.sh
echo '<?php echo "hi";' > /tmp/hi.php
PHP_COMPILER_AOT_USER_SCRIPT=1 php bin/compile.php -o /tmp/hi_bin /tmp/hi.php && /tmp/hi_bin
# master: hi / exit 0
# branch (defer removed): phpc: fatal signal (segfault) after c:main_after_init / exit 139

Conclusion: EnvironMirrorRuntimeUserScriptCstr (~182 LOC libc environ LLVM) must stay until user-script AOT can safely call EnvironMirrorNativeJitHelper through helper-runtime at init without nested-JIT or segfault — likely needs the same prelink/unit work that unblocked ProcessExecCaptureNativeJitHelper (#19006) applied to environ mirror, or an init-safe PHP stub that does not pull nested helpers.

Unit shrink tests pass; AOT smoke is the gate.

[PurHur]

claim: PHP Runtime → PHP — continuing this run (helper-runtime prelink + delete UserScriptCstr).

[PurHur]

Merged via #19168.

Root cause: Removing the defer branch without fixing init-time semantics segfaulted — EnvironMirrorNativeJitHelper called VmEnvEnvironNative::enumerate() which reads /proc/self/environ via fopen at main_after_init (same failure mode documented in the prior blocker).

Fix: Init-safe libc environ walk consolidated into EnvironLibcWalkJit + phpc_native_environ_mirror_into_ht; VmEnvEnvironNative::mirrorIntoNativeHashtable() is the SSOT entry; all paths route through JitVmHelperLink + prelinked helper-runtime unit.

C shrink: Deleted EnvironMirrorRuntimeUserScriptCstr.php (~182 LOC dedicated defer LLVM).

Verification:

• EnvironMirrorRuntimeShrinkTest — OK (6 tests)
• User-script AOT smoke hi — exit 0
• make bootstrap-selfhost-vm-driver-execute-probe — OK