Self-host M3/M5: native emit bin/compile.php via inventory compile driver (not emit-helper TU only) #2843

Milestone

M3 (emit) / M5 (full Compiler CFG) — parent #1492

Problem

M3 strict probes pass via dedicated emit-helper TUs (helloworld_m3_emit_native_entry.php, compile_smoke_m3_emit_native_entry.php). PHP_COMPILER_M3_SOURCE=bin/compile.php via bootstrap-selfhost-helloworld-compile-bin.sh is green on harness 2026-05-27, but production bootstrap still cannot treat bin/compile.php parsed as the inventory compile driver (full Runtime::parseAndCompile on the driver file itself) as the default emit path for arbitrary spine sources.

Gap: closing #2827 proved helper-TU emit; remaining work is honest inventory-scale CFG through the same entrypoints scripts use for real compiles (no parallel emit TU), matching docs/bootstrap-selfhost.md “inventory-scale bin/compile.php emit-TU” notes.

Scope

Repro

# Green (helper / sidecar path):
./script/docker-exec.sh -- bash -lc 'make bootstrap-selfhost-helloworld'
./script/docker-exec.sh -- bash -lc '
  export PHP_COMPILER_M3_SOURCE=bin/compile.php
  ./script/bootstrap-selfhost-helloworld-compile-bin.sh
'

# Target (implementer defines exact env — no helper TU):
./script/docker-exec.sh -- bash -lc '
  source script/php-env.sh
  export BOOTSTRAP_M3_LINK_COMPILE_DRIVER=1
  export BOOTSTRAP_M3_COMPILE_DRIVER_REAL_LOWERING=1
  export BOOTSTRAP_M3_RUNTIME_COMPILE=1
  export BOOTSTRAP_M3_HELLOWORLD_STRICT=1
  export PHP_COMPILER_M3_SOURCE=bin/compile.php
  export PHP_COMPILER_M3_COMPILE_MODE=compile
  # run compile_driver.php from selfhost spine binary — emit_path=native, no *_m3_emit_native_entry.php
'

Done when

• Strict HelloWorld / compile-smoke probes can pass with BOOTSTRAP_M3_USE_INVENTORY_EMIT_DRIVER=1 (name TBD) — no *_m3_emit_native_entry.php in the link line
• bin/compile.php native compile of test/selfhost/compiler_lib_spine_smoke/main.php via compiled driver logs emit_path=native
• docs/bootstrap-selfhost.md M3 HelloWorld row no longer describes emit-helper as the only native path

Labels

self-host, bootstrap, IMPORTANT

Links

#1492 · #2827 ✅ (helper TU) · #1768 (allowlist batches) · #1402