Self-host M3: lib/Runtime.php native compile batch (parser front-door after #2216)

[PurHur]

Problem

#2216 probes native compile of lib/Compiler.php as a single unit. Self-host M3 needs the parser/runtime front-door compiled honestly next: lib/Runtime.php wires nikic/php-parser, php-cfg traversers, and new Compiler() — the path every bin/vm.php invocation uses.

Today inventory shows heavy new * warnings in lib/Runtime.php but 0 blockers; emit still uses Zend fallback in M3/M4 smokes.

Goal

First multi-construct M3 batch after unit probe green:

1. Native AOT emit (or documented partial) for lib/Runtime.php + minimal require_once closure (no full 611 tree)
2. BOOTSTRAP_RUNTIME_COMPILE_SMOKE=1 script or PHPUnit probe: compiled artifact can parse+compile a trivial <?php echo 1;
3. Update docs/self-host-target.md M3 row with honest vs Zend emit
4. Triage output from Tooling: bootstrap-inventory-triage.php — top CFG gaps across 611 files #2254 ranks remaining blockers in this file

Implementation hints

Piece	Path	Notes
Probe	script/bootstrap-selfhost-runtime-compile-smoke.sh	Mirror bootstrap-selfhost-compile-smoke-probe.sh
Bundle	test/selfhost/ or docs/bootstrap-profile.json	Smallest require_once closure for Runtime
Compiler gaps	#58, #101, #145, #2273, #2286	Class methods, extends, unset, static locals
Inventory	php script/bootstrap-inventory.php	Before/after warning count for lib/Runtime.php

Suggested order

1. Run ./phpc doctor --selfhost + Tooling: bootstrap-inventory-triage.php — top CFG gaps across 611 files #2254 triage on lib/Runtime.php only
2. Close CFG gaps ranked in Self-host: Unknown Stmt Type lowering batch tracker (post-#2254 triage) #2276 batches scoped to this file
3. Land probe script before flipping CI: BOOTSTRAP_M3_COMPILE_SMOKE_STRICT_GATE opt-in in ci-local after #1937 #1968 strict gates

Acceptance criteria

BOOTSTRAP_RUNTIME_COMPILE_SMOKE=1 ./script/bootstrap-selfhost-runtime-compile-smoke.sh
php script/bootstrap-inventory.php --check

Harness:

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && BOOTSTRAP_RUNTIME_COMPILE_SMOKE=1 ./script/bootstrap-selfhost-runtime-compile-smoke.sh'

Verification (local / Docker only)

No GitHub Actions (#394 ✅). Full gate: make test-harness after probe lands.

Dependencies

• Self-host M3: native compile-driver probe on lib/Compiler.php unit #2216 — lib/Compiler.php unit probe (predecessor)
• Self-host M3: compile-driver real lowering symbol batch tracker #1768 — M3 compile-driver honest emit batches
• Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492 epic · Tooling: bootstrap-inventory-triage.php — top CFG gaps across 611 files #2254 triage · DevEx: phpc doctor --selfhost — top CFG gaps from bootstrap-inventory-triage (#2254) #2285 doctor integration

Links

• ROADMAP 🗺️ ROADMAP: Self-host + web-capable PHP subset (living) #78 Phase 1 Language (self-host spine)
• docs/bootstrap-inventory.md · lib/Runtime.php

[PurHur]

Landed on master (May 2026)

• fix: Doctor.php phpdoc for bootstrap AOT link #2307 — lib/Doctor.php phpdoc fix (spine/AOT link)
• feat(selfhost): M3 Runtime compile smoke CI/docs integration (#2294) #2308 — M3 Runtime compile smoke probe + CI/docs (Self-host M3: lib/Runtime.php native compile batch (parser front-door after #2216) #2294)

Probe (partial M3, same ladder as compile-smoke)

./script/bootstrap-selfhost-runtime-compile-smoke.sh → bundle runtime_compile_smoke bundle OK, emit_path=zend partial, native run of <?php echo 1; → stdout 1.

Native emit TU: runtime_m3_emit_native_entry.php + runtime_compile_smoke_m3_emit(); opt-in BOOTSTRAP_M3_LINK_COMPILE_DRIVER=1 / BOOTSTRAP_M3_COMPILE_DRIVER_REAL_LOWERING=1 (blocked at link/runtime init like compile-smoke — #1937).

Gates

• BOOTSTRAP_RUNTIME_COMPILE_SMOKE_PROBE_GATE=1 (default in ci-defaults.env)
• Strict: BOOTSTRAP_M3_RUNTIME_COMPILE_SMOKE_STRICT_GATE=0 until emit_path=native stable

Still open for this issue

• Native emit_path=native via Runtime parseAndCompile (CFG/compiler gaps Language: Class methods and property access in JIT #58, Compiler: Class inheritance (extends) and interfaces #101, Language: Visibility, constructors, and destructors #145, Language: unset() on variables, array elements, and object properties #2273, Language: function-local static variables (static $x in functions) #2286 per Tooling: bootstrap-inventory-triage.php — top CFG gaps across 611 files #2254 triage)
• Flip strict gate when emit TU green

[PurHur]

M3 runtime emit probe (2026-05-26)

Link gate (BOOTSTRAP_M3_LINK_COMPILE_DRIVER=1 + BOOTSTRAP_M3_COMPILE_DRIVER_REAL_LOWERING=1 → probe sets PHP_COMPILER_SELFHOST_AOT=1 PHP_COMPILER_M3_COMPILE_DRIVER=1 PHP_COMPILER_EMIT_HELPER_LINK=1):

• runtime_m3_emit_native_entry.php → link OK (build/selfhost-runtime-compile-emit ~300KB)
• Raw php bin/compile.php … with only BOOTSTRAP_M3_* (no PHP_COMPILER_M3_COMPILE_DRIVER=1) → JIT compile fail (LogicException: Other class body types are not jittable)

Runtime gate (BOOTSTRAP_M3_RUNTIME_COMPILE=1, source runtime_trivial_echo.php):

• Emit binary exits 0 with no stdout and no output AOT (block_reason=native emit runtime failed (ok) in probe — false-positive exit code)
• Root cause: PHPCompiler_BootstrapAot_runtime_compile_smoke_m3_emit is a self-host stub (xor eax,eax; ret) via isSkippedBootstrapInterpreterHotPathName() \bootstrapaot\ rule — unlike compile_smoke_m3_emit, which gets BootstrapCompileSmokeM3Emit native bridge when PHP_COMPILER_EMIT_HELPER_LINK=1

Attempted incremental fix (allowlist/skip-path: exempt runtime_compile_smoke_m3_emit from bootstrapaot stub + wire native bridge or PHP CFG lowering):

• Link phase → LLVM 9 segfault (exit 139) — same as compile_smoke_m3_emit_native_entry.php bridge link on this host (8/8 retries)

Next: unblock emit TU without LLVM 9 link regression — either shrink bridge IR (#1983) or C floor for emit entry; cannot flip emit_path=native until runtime_compile_smoke_m3_emit: compile OK is real, not stub.