php-in-php: delete JitFilePutContentsLibc/JitReadfileLibc — VmFsWritePure must not recurse via file_put_contents (#1492)

[PurHur]

Category

php-in-php · runtime-shrink (#1492, follow #19339 FGC / #19966 / #20256 handoff)

Problem

StringFilePutContents / StringReadfile still fork isThinStandaloneAotMain() → Jit*Libc while embed uses helpers. Helpers call phpc_*_kernel which re-emits the same libc. Always-helper (FGC #19339 shape) was blocked because VmFsWritePure::write() calls host \file_put_contents(), which NestedJIT lowers back into __compiler_file_put_contents → helper → recursion (writes fail / return 0).

Mode	Today	Target
Embed / non-thin	Helper → phpc_*_kernel libc	Helper → VmFs::* (FGC/Unlink shape)
Thin standalone AOT	Direct Jit*Libc on ABI	Same helper bridge (no thin fork)
VmFsWritePure	\file_put_contents (recurses under NestedJIT)	fopen/fwrite/fclose (StreamIo / no FPC ABI)

php-src reference

• php/php-src ext/standard/file.c — php_file_put_contents
• php/php-src ext/standard/streamsfuncs.c — php_stream_passthru

PHP implementation target

• ext/standard/VmFsWritePure.php — rewrite without \file_put_contents (fopen/fwrite/flock/fclose; keep APPEND + LOCK_EX)
• ext/standard/FilePutContentsJitHelper.php — VmFs::filePutContents (false→-1)
• ext/standard/ReadfileJitHelper.php — VmFs::readfile (false→-1)
• lib/JIT/Builtin/StringFilePutContents.php / StringReadfile.php — always JitVmHelperLink; drop implementLibcBody / isThinStandaloneAotMain
• Delete JitFilePutContentsLibc.php, JitReadfileLibc.php, phpc_file_put_contents_kernel.php, phpc_readfile_kernel.php; drop Module + spine requires
• Update FilePutContentsRuntimeShrinkTest / ReadfileRuntimeShrinkTest

Repro

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
vendor/bin/phpunit test/unit/FilePutContentsRuntimeShrinkTest.php test/unit/ReadfileRuntimeShrinkTest.php
vendor/bin/phpunit test/aot/AotTest.php --filter file_put_contents
vendor/bin/phpunit test/aot/AotTest.php --filter readfile
PHP_COMPILER_HELPER_RUNTIME_O=1 PHP_COMPILER_AOT_USER_SCRIPT=1 ./phpc build -o /tmp/fpc-aot test/fixtures/aot/cases/file_put_contents.phpt
make bootstrap-selfhost-vm-driver-execute-probe
php script/bootstrap-inventory.php --check
'

Done when

• VmFsWritePure no longer calls \file_put_contents
• Both Jit*Libc + phpc_*_kernel files deleted
• No isThinStandaloneAotMain / implementLibcBody on FPC/readfile ABI path
• Helpers call VmFs; shrink + AOT fixtures green
• make bootstrap-selfhost-vm-driver-execute-probe green
• PR body cites lines/files removed

Refs #1492, #19339, #19966, #20256

[PurHur]

claim: PHP Runtime → PHP — starting this run

Pillar 1 (this workspace):

Gate	Result
make bootstrap-selfhost-link	OK /compiler/build/selfhost
php script/bootstrap-inventory.php --check	OK 5519/5519
./script/release-readiness.sh --json	user_release_ready: **yes** (inventory, spine, north-star5-fast, vm-driver-probe ok)

Root cause for prior NestedJIT blocker: VmFsWritePure::write() calls \file_put_contents → recurses into __compiler_file_put_contents under NestedJIT. Fix WritePure first, then always-helper + delete Jit*Libc / phpc_*_kernel.

[PurHur]

Progress (this run) — PR #20275

Shipped (foundation)

1. VmFsWritePure — fopen/fwrite/fclose (no \file_put_contents) so NestedJIT cannot recurse into the FPC ABI.
2. phpc_file_put_contents_kernel flags — JitLongArg::lower instead of trunc(loadValue). This unblocked:

   php script/emit-helper-runtime-object.php --unit=/ext/standard/FilePutContentsJitHelper.php
   

   (was: Trunc only operates on integer — trunc %__value__ to i64).

Still blocked — delete thin fork / always-helper

Experiment	Result
Always JitVmHelperLink + helper → phpc_*_kernel (no isThinStandaloneAotMain)	AOT file_put_contents returns 0; file may be written by thin path only
Helper → VmFs::filePutContents / direct fopen	Same 0 / NestedJIT StreamIo write not honest under user-script
Unwrap __value__→i64 in coerceHelperScalarResult via __value__readLong	Runtime 0 still; also free(): invalid pointer on vm-driver-probe — reverted

Root cause for return 0: NestedJIT *JitHelper methods return boxed __value__; FPC/readfile bridges call coerceBridgeResult(..., i64) which does not extract longs from boxes (unlike string via extractStringPtrFromHelperResult). Needs a careful boxed-int coerce (not the naive readLong that corrupted probe).

Master thin fork remains load-bearing — proven: with thin libc ABI, AOT writes n=3 / file size 3; without it, n=0.

Next step

Safe __value__→i64 in JitNestedHelperCoerce::coerceHelperScalarResult (with probe green) → always-helper → then optional delete Jit*Libc once VmFs leaf NestedJIT write is honest.

[PurHur]

claim: PHP Runtime → PHP — continuing this run

Pillar 1 (this workspace):

Gate	Result
php script/bootstrap-inventory.php --check	OK 5522/5522
docker info	ok
prior foundation	#20275 merged (VmFsWritePure fopen + JitLongArg flags)

This run: safe __value__→i64 extract for FPC/readfile bridges only (not global coerceHelperScalarResult — prior global readLong hit bool boxes / probe free(): invalid pointer). Then drop isThinStandaloneAotMain thin fork; keep phpc_*_kernel NestedJIT leaf until StreamIo honesty allows delete.

[PurHur]

Progress (this run) — PR #20282

Shipped

• extractLongFromHelperResult — scoped __value__→i64 unwrap for FPC/readfile helper bridges (not global coerceHelperScalarResult — that hit bool boxes / probe free(): invalid pointer last run).
• Thin user-script AOT still green (file_put_contents → 3 bytes); vm-driver-execute-probe OK.

Always-helper still blocked (deeper than coerce)

Experiment	Result
Drop thin fork → always JitVmHelperLink + helper → phpc_*_kernel	n=0, file missing. Final binary has no __phpc_file_put_contents_libc — NestedJIT of FilePutContentsJitHelper does not take Internal::call() libc leaf
Helper → VmFs::filePutContents / WritePure fopen/fwrite	NestedJIT user-script AOT of fopen SIGABRT
Thin isThinStandaloneAotMain → JitFilePutContentsLibc	still load-bearing (n=3)

Next step

Make NestedJIT of phpc_file_put_contents_kernel / phpc_readfile_kernel honor Internal::call() (emit __phpc_file_put_contents_libc) inside helper TU / inlined NestedJIT — or fix NestedJIT fopen/fwrite so VmFs leaf is honest. Then drop thin fork + optionally delete Jit*Libc / phpc_*_kernel.

Refs #20282