Language: User __destruct() — JIT/AOT invoke on object release (phase 2 of #3144)

[PurHur]

Category

language | runtime

Problem

#3144 closed VM __destruct() — refcount drop and shutdown pass call user destructors. Capability matrix: JIT = no, AOT = no.

Native-compiled apps that rely on destructors for resource cleanup (locks, handles, flush buffers) still need VM execution or miss destructor calls in JIT/AOT paths.

php-src reference

• php/php-src Zend/zend_objects.c — zend_objects_destroy_object
• php/php-src Zend/zend_execute_API.c — shutdown destructor pass

Repro (today)

<?php
class D {
    public function __destruct() {
        echo "bye\n";
    }
}
new D();
echo "end\n";

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/vm.php repro_destruct.php'
# VM: bye before end

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh && php bin/jit.php repro_destruct.php'
# JIT: verify __destruct runs at end of script / scope (may differ today)

Runtime	Expected (Zend order)	end then bye on scope end / request shutdown
VM	#3144 behavior
JIT/AOT	Match VM ordering

Scope (this repo)

Area	Files
VM	lib/VM.php — destructor queue / invokeDestructors (reference)
JIT/AOT runtime	Register destructor callbacks at TYPE_NEW sites; run at function return / script end
Tests	test/compliance/cases/language/destruct_user.phpt (+ jit)
Matrix	class_destruct row in script/capability-syntax-lib.php

Done when

• Repro prints end then bye under bin/jit.php (same as VM)
• AOT binary prints same sequence at process exit
• Circular references still require gc_collect_cycles() for cycle destructors (document if VM-only)

Verification

./script/ci-fast.sh --filter destruct_user

Links

• Epic Epic: Self-host critical path — compiler compiles itself (M3→M5) #1492 · Parent Language: User __destruct() — invoke destructors on object free (Zend parity) #3144 · __clone already JIT (Language: __clone magic method — invoke user hook on clone (Zend parity) #3170)

[PurHur]

claim: cursor-agent-lane-c — starting this run

[PurHur]

WIP handoff (lane C) — branch agent/issue-4013-user-destruct-jit-aot

Done

• GC runtime: phpc_destruct_*, phpc_gc_run_shutdown_destructors, main {main} deferral (phpc_destruct_set_allow_delref(0))
• LLVM: __object__invoke_destructor + class-id dispatch (clone-style), shutdown hook from Object_::shutdown()
• Refcount delref: defer destroy when allow=0; invoke destructor before free when allow=1
• Tests: destruct_user.phpt, class_destruct_user.phpt (AOT fixture)

Verification (Docker)

php bin/vm.php test/repro-maintainer/destruct_user_4013.php
# end\nbye\n — OK

vendor/bin/phpunit --filter destruct_user
# VM: pass | JIT: exit -1 | AOT: extra binary garbage after bye (heap corruption)

Blockers before merge

1. AOT: repro prints end + bye then corrupts stdout (superglobal-like binary dump) — needs phpc_object_release_storage / shutdown ordering fix
2. JIT/MCJIT: harness exit -1; bin/jit.php -r 'echo 1' segfaults on this harness host even on master (environment), but destructor JIT path needs MCJIT verify once host is sane

Next: fix post-destructor release so AOT output is exactly end\nbye\n; re-enable JITTest class_destruct* when JIT execute is green.

[PurHur]

Merged via #4018 (squash).

Root cause: phpc_gc_run_shutdown_destructors ran at the end of __shutdown__ after compile-time string frees and sg_* hashtable teardown, so destructor/echo paths could run against freed $_SERVER/literal storage (~4KB garbage on stdout).

Fix: Emit phpc_gc_run_shutdown_destructors from main after standalone OB flush and before __shutdown__; treat __destruct as void in JIT lowering; GC shutdown invokes destructors with delref still deferred, then releases storage.

Verification:

php bin/vm.php test/repro-maintainer/destruct_user_4013.php
# end / bye

vendor/bin/phpunit --filter class_destruct_user
# OK (1 test)

php bin/compile.php -o /tmp/t - < test/repro-maintainer/destruct_user_4013.php && /tmp/t | od -c
# 0000000   e   n   d  \n   b   y   e  \n

php-src reference: Zend/zend_objects.c (zend_objects_destroy_object / shutdown ordering).