Self-host M3: compile-driver real lowering symbol batch tracker

[PurHur]

Problem

M3 compile-driver native emit still falls back to Zend (emit_path=zend partial) because lib/JIT.php only real-lowers a hand-maintained allowlist (isM3CompileDriverRealLoweringName(), m3CompileDriverSpineDenyNames()). Each new symbol can link yet return null at execute until init/parse spine is real (#2566, #2568).

SSOT files

Piece	Path
Allowlist / deny	lib/JIT.php — isM3CompileDriverRealLoweringName(), m3CompileDriverSpineDenyNames(), compileRuntime*M3Native()
Snapshot guard	docs/m3-allowlist-snapshot.txt — #1905 / M3_ALLOWLIST_SYNC_GATE=1
Emit entries	test/bootstrap-aot/*_m3_emit_native_entry.php
Init bridge	lib/JIT/RuntimeEmitTuInit.php, lib/JIT/BootstrapCompileSmokeM3Emit.php
Stub policy	lib/JIT/SelfHostBuiltinPolicy.php — retirement tracked in #1520
Playbook	docs/bootstrap-m5-fast-path.md

Ordered batches (May 2026 harness status)

Batch A — Runtime bootstrap (ctor, initVmContext, parse pipeline)  ❌ BLOCKED
  Owner: #2568 (initParsePipeline/initCompiler/loadCoreModules)
  Gate:  BOOTSTRAP_M3_RUNTIME_COMPILE=1 ./script/bootstrap-selfhost-runtime-compile-smoke.sh
  Today: parseAndCompile returned null (link OK)

Batch B — Parse bridge (parseAndCompile / parseAndCompileEmitSmoke native)  ❌ BLOCKED
  Owner: #2566
  Gate:  same as Batch A + compile-smoke probe
  TU ladder: #2559 → #2561 → #2567

Batch C — Compiler::compileCfg* hot paths + stub retirement (#1520)  📋
  Gate:  COMPILER_DRIVER_SMOKE_GATE=1 make bootstrap-selfhost-compiler-driver-smoke

Batch D — Emit-TU execute gate  📋 (after A+B)
  Gate:  ./script/bootstrap-m3-emit-tu-execute.sh (#2552 reopened)

Batch E — Native bin/compile.php execute → #2466 (after Batch D + #2540 if needed)

After each batch:

php script/check-m3-allowlist-snapshot.php
BOOTSTRAP_M3_RUNTIME_COMPILE=1 ./script/bootstrap-selfhost-runtime-compile-smoke.sh
BOOTSTRAP_M3_HELLOWORLD_STRICT=1 ./script/bootstrap-selfhost-helloworld-probe.sh

Prerequisites

• M2 spine link ✅ (BOOTSTRAP_LIB_SPINE_SMOKE=1)
• M2 inventory doc freshness ❌ Self-host: bootstrap-inventory.php --check fails (committed doc vs live probe) #2501 (parallel)

Acceptance criteria

• Batch A+B merged; Self-host M3: runtime_m3_emit execute — parseAndCompile returned null (smallest emit TU) #2559 prints compile OK / emit_path=native
• Allowlist snapshot green
• Self-host M3: make HelloWorld strict (no Zend emit fallback) the default gate after emit_path=native #2522 unblocked (M3 strict default-on)

Links

• Self-host M3: Runtime::parseAndCompile native spine returns null in emit-TU bridge #2566 · Self-host M3: initParsePipeline/initCompiler native stubs leave Runtime unready for parseAndCompile #2568 · Self-host M3: runtime_m3_emit execute — parseAndCompile returned null (smallest emit TU) #2559–Self-host M3: helloworld_m3_emit execute — parseAndCompile returned null (HelloWorld emit TU) #2567 · Self-host M3: bootstrap-m3-emit-tu-execute.sh green (emit helper run, no Zend) #2552 · Self-host M3: PHPTypes/CFG static init in emit-TU LLVM global ctor (link segfault) #2540
• Self-host M3: Native emit for compiler compile-smoke fixture (post-#1493) #1937 ✅ · Epic Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492 · 🗺️ ROADMAP: Self-host + web-capable PHP subset (living) #78