php-in-php: delete JitGetenvKernel libc defer — always JitVmHelperLink + GetenvJitHelper PHP (#1492)

[PurHur]

Category

php-in-php · runtime-shrink (#1492, peer EnvironMirror #19157 / Bz2 #20117 / rename #20028)

Problem

lib/JIT/Builtin/StringGetenv.php still gates inventory / user-script / StreamIo-defer AOT through StreamIoRuntime::shouldDeferHeavyStreamIoEmitters() → JitGetenvKernel raw libc getenv(3). Embed uses GetenvJitHelper PHP overlay (putenv-local + VmEnvEnvironNative), so thin/user-script AOT misses the overlay and duplicates libc in LLVM.

GetenvJitHelper emits as a helper-runtime unit with runtime_safe: true + init_via_global_ctor — same shape as EnvironMirrorNative / Bz2. JitVmHelperLink::ensureCompiled clears PHP_COMPILER_AOT_USER_SCRIPT during NestedJIT (#16075), so always-helper is viable.

Mode	Today	Target
Embed / non-defer	GetenvJitHelper bridge	unchanged
StreamIo defer / user-script / inventory	JitGetenvKernel libc	JitVmHelperLink → GetenvJitHelper
StringGetenvAll defer stub	empty/minimal LLVM stub	same helper path

php-src reference

• php/php-src ext/standard/basic_functions.c — zif_getenv / zif_putenv

PHP implementation target

• lib/JIT/Builtin/StringGetenv.php — always JitVmHelperLink::ensureCompiled + existing out-param bridge; drop StreamIo defer / JitGetenvKernel
• lib/JIT/Builtin/StringGetenvAll.php — drop defer inventory stub; always helper bridge
• Delete ext/standard/JitGetenvKernel.php
• Update test/unit/GetenvJitRuntimeShrinkTest.php + spine require list
• Prelink prelinked/helper-runtime/*/units/ext_standard_GetenvJitHelper_php/ when emitting

Repro

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
vendor/bin/phpunit test/unit/GetenvJitRuntimeShrinkTest.php
PHP_COMPILER_AOT_USER_SCRIPT=1 ./phpc build -o /tmp/getenv_aot test/fixtures/aot/cases/getenv_putenv.phpt 2>/dev/null || true
# fixture smoke:
php -r "echo \"see AotTest getenv_putenv / getenv_local_only\";"
vendor/bin/phpunit --filter getenv test/aot/AotTest.php
make bootstrap-selfhost-vm-driver-execute-probe
'

Done when

• JitGetenvKernel.php deleted
• UserScriptAotDeferNestedJit / shouldDeferHeavyStreamIoEmitters removed from getenv bridge path
• Shrink + AOT getenv fixtures green (putenv overlay visible under user-script AOT)
• make bootstrap-selfhost-vm-driver-execute-probe green
• PR body cites lines removed (kernel + defer gates)

Refs #1492, #19373, #19157, #20117, #9092

[PurHur]

claim: PHP Runtime → PHP — starting this run

Pillar 1 trust (this host):

• make bootstrap-selfhost-link → OK /compiler/build/selfhost
• php script/bootstrap-inventory.php --check → OK 5504/5504
• ./script/release-readiness.sh --json → user_release_ready: yes (inventory, spine, root-readme, north-star5-fast, vm-driver-probe)
• GetenvJitHelper local helper-runtime emit → runtime_safe: true, init_via_global_ctor: true

Migrating StringGetenv / StringGetenvAll to always JitVmHelperLink + GetenvJitHelper; delete JitGetenvKernel libc defer.

[PurHur]

Pivot (verified): always-JitVmHelperLink → GetenvJitHelper returns empty/false under phpc build (PHP_COMPILER_AOT_USER_SCRIPT=1) — VmEnvEnvironNative::enumerate() / NestedJIT cannot see process environ (#16075). Same constraint as htmlspecialchars #20141.

Revised target (#20011 / #20141 shape):

• Gate thin path on Context::isThinStandaloneAotMain() (drop StreamIoRuntime::shouldDeferHeavyStreamIoEmitters)
• Keep JitGetenvKernel libc for thin standalone
• Embed/non-thin: JitVmHelperLink::ensureCompiled + coerce via JitNestedHelperCoerce::valueBoxPtrFromHelperResult
• Move getenv ensureStandaloneBodies outside standaloneInitPhase in Context
• StringGetenvAll: thin stub entry; non-thin helper fill

Master AOT getenv fixtures already fail getenv_all + getenv_local_only the same way — no new regression.

[PurHur]

Merged via #20160

Verification:

• GetenvJitRuntimeShrinkTest + EnvLocalRuntimeShrinkTest + standalone getenv tests OK
• AOT thin smoke: path=ok via JitGetenvKernel
• AOT fixtures: same 2 master-red cases (getenv_all, getenv_local_only) — no new regression
• bootstrap-selfhost-vm-driver-execute-probe OK
• inventory OK 5504/5504, spine sync OK

Outcome: StreamIo defer removed; thin AOT keeps libc kernel; embed uses JitVmHelperLink + coerce. Always-helper blocked by #16075 environ NestedJIT (documented pivot).

[PurHur]

Confirmed merged: #20160 (99b6cf72).

Squash after rebase onto master (inventory doc regen). Gates green as in prior comment.