AOT: fix request_parse_body compile/link (#5965)

[PurHur]

Summary

Continued #5965 — AOT standalone putenv() compile+execute fixed; request_parse_body() AOT execute still blocked.

Root fixes (commit 6fff073):

• BasicBlockHelper::restoreInsertBlock(null) — standalone init no longer TypeErrors (Stdlib: request_parse_body() — PHP 8.4 HTTP body parser without superglobals (ext/standard/http.c) #5965)
• StringGetenv::implement preserves insert block after bridge emit — fixes "Current basic block has no parent function" on AOT compile
• JitEnv::putenv routes standalone through GetenvJitHelper::putenv via JitNestedHelperCoerce (avoids __compiler_env_register_putenv segfault)
• RequestParseBodyEngine::overlayGetenv reads JIT putenv overlay + libc environ for CONTENT_TYPE/REQUEST_BODY
• Defer RequestParseBodyRuntime from ensureMinimalUserStandaloneBodies (lazy link on first call)

php-src ref: ext/standard/http.c (request_parse_body), ext/standard/basic_functions.c (putenv/getenv)

Verification (2026-07-12, Docker)

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && export PHP_COMPILER_PROFILE=8.4

# VM — green
php bin/vm.php test/repro/issue_5965_aot_index.php
# array ('a' => '1', 'b' => 'two')

# AOT putenv-only — green
php bin/compile.php -o /tmp/pe test/repro/issue_5965_putenv_only.php && /tmp/pe
# ok

vendor/bin/phpunit test/unit/JIT/EnvLocalRuntimeStandaloneTest.php
# OK (2 tests, 9 assertions)

# AOT request_parse_body — still red
php bin/compile.php -o /tmp/rpb test/repro/issue_5965_aot_index.php && /tmp/rpb
# phpc: fatal signal (segfault) after c:main_before_php — exit 139

vendor/bin/phpunit test/aot/AotTest.php --filter request_parse
# FAIL exit 139/134

# AOT putenv.phpt fixture — getenv after putenv returns empty (overlay not visible via __compiler_getenv bridge)
vendor/bin/phpunit test/aot/AotTest.php --filter putenv
# FAIL expected production, got empty string
'

Blockers (next run)

1. request_parse_body AOT execute — any script calling request_parse_body() segfaults before user output; VM green. Bisect JIT call() return / nested RequestParseBodyJitHelper link.
2. putenv→getenv AOT — standalone nested putenv does not populate overlay visible to __compiler_getenv; need unified helper path for both or fix register bridge without segfault.

Closes #5965 when AOT fixtures request_parse_body_{urlencoded,multipart}.phpt + putenv.phpt execute green.

[PurHur]

Maintainer triage 2026-07-08: compile/link green per PR body but AOT runtime still segfaults at c:main_before_php — not merge-ready until execute repro passes. Re-run bootstrap not required (stdlib/AOT path only).

[PurHur]

Maintainer triage 2026-07-08: compile/link green per PR body but runtime segfault remains — hold merge until AOT execute passes issue repro.

[PurHur]

Continued work (2026-07-12, lane C)

Pushed 6fff07342 — partial progress on AOT execute blocker.

Fixed

• AOT putenv() — route standalone lowering through JitNestedHelperCoerce::callHelper → GetenvJitHelper::putenv (drops broken __compiler_env_register_putenv malloc bridge path)
• Standalone init compile — BasicBlockHelper::restoreInsertBlock(?BasicBlock) + StringGetenv insert-block restore (fixes TypeError during ensureMinimalUserStandaloneBodies)
• VM env overlay for parser — RequestParseBodyEngine::overlayGetenv() checks JIT overlay then VmEnv
• Lazy link — stop eager RequestParseBodyRuntime::ensureLinked in standalone init (match putenv lazy helper compile)

Verification (Docker)

PHP_COMPILER_CI_SINGLE_CONTAINER=0 ./script/docker-exec.sh -- bash -lc '
source script/php-env.sh && export PHP_COMPILER_PROFILE=8.4
php bin/vm.php test/repro/issue_5965_rpb_only.php
tmpdir=$(mktemp -d)
php bin/compile.php -o "$tmpdir/pe" test/repro/issue_5965_putenv_only.php && "$tmpdir/pe"
vendor/bin/phpunit test/unit/JIT/EnvLocalRuntimeStandaloneTest.php
'

• VM issue_5965_rpb_only.php — PASS
• AOT issue_5965_putenv_only.php — PASS (ok, exit 0)
• EnvLocalRuntimeStandaloneTest — PASS

Still red (blocker)

• AOT request_parse_body() — segfault (139) even when RequestParseBodyJitHelper::parseIntoNative body is empty
• Bisect: skipping __compiler_request_parse_body bridge helper call avoids segfault; any call to parseIntoNative from bridge or builtin crashes
• Next: align with working GetenvJitHelper pattern (helper compiled in user-script TU, not init TU) + link ParseStrNativeJitHelper when re-enabling lazy compile; investigate nested-helper MCJIT entry / helper-runtime .o link

Not merge-ready until test/fixtures/aot/cases/request_parse_body_{urlencoded,multipart}.phpt execute green.