Fix a memory leak in tracig JIT when the same closure is called through Closure::call() and natively.

Closure::call() makes a temporary copy of original closure function, modifies its
scope, resets ZEND_ACC_CLOSURE flag and call it through zend_call_function().
As result the same function may be called with and without
ZEND_ACC_CLOSURE flag, that confuses JIT and may lead to memory leak or
even worse memory errors.

The patch allocates "fake" closure object and keep ZEND_ACC_CLOSURE flag
to always behave in the same way.

Author: dstogov

Zend/zend_closures.c

@@ -160,15 +160,21 @@ ZEND_METHOD(Closure, call)
 		/* copied upon generator creation */
 		GC_DELREF(&closure->std);
 	} else {
+		zend_closure *fake_closure;
 		zend_function *my_function;
+
+		fake_closure = emalloc(sizeof(zend_closure));
+		memset(&fake_closure->std, 0, sizeof(fake_closure->std));
+		fake_closure->std.gc.refcount = 1;
+		fake_closure->std.gc.u.type_info = GC_NULL;
+		ZVAL_UNDEF(&fake_closure->this_ptr);
+		fake_closure->called_scope = NULL;
+		my_function = &fake_closure->func;
 		if (ZEND_USER_CODE(closure->func.type)) {
-			my_function = emalloc(sizeof(zend_op_array));
 			memcpy(my_function, &closure->func, sizeof(zend_op_array));
 		} else {
-			my_function = emalloc(sizeof(zend_internal_function));
 			memcpy(my_function, &closure->func, sizeof(zend_internal_function));
 		}
-		my_function->common.fn_flags &= ~ZEND_ACC_CLOSURE;
 		/* use scope of passed object */
 		my_function->common.scope = newclass;
 		if (closure->func.type == ZEND_INTERNAL_FUNCTION) {
@@ -194,10 +200,8 @@ ZEND_METHOD(Closure, call)
 			if (fci_cache.function_handler->common.fn_flags & ZEND_ACC_HEAP_RT_CACHE) {
 				efree(ZEND_MAP_PTR(my_function->op_array.run_time_cache));
 			}
-			efree_size(my_function, sizeof(zend_op_array));
-		} else {
-			efree_size(my_function, sizeof(zend_internal_function));
 		}
+		efree_size(fake_closure, sizeof(zend_closure));
 	}
 
 	if (Z_TYPE(closure_result) != IS_UNDEF) {

ext/opcache/tests/jit/closure_001.phpt

@@ -0,0 +1,46 @@
+--TEST--
+Closures should be always called with ZEND_ACC_CLOSURE flag set 
+--INI--
+opcache.enable=1
+opcache.enable_cli=1
+opcache.file_update_protection=0
+opcache.jit_buffer_size=1M
+opcache.protect_memory=1
+opcache.jit_hot_func=2
+--EXTENSIONS--
+opcache
+--FILE--
+<?php
+class Foo {
+}
+
+function bar() {
+    return function () {
+        return function () {
+            return function () {
+                return 42;
+            };
+        };
+    };
+}
+
+$foo = new Foo;
+$f = bar();
+
+var_dump($f->call($foo));
+var_dump($f->call($foo));
+var_dump($f());
+?>
+--EXPECT--
+object(Closure)#3 (1) {
+  ["this"]=>
+  object(Foo)#1 (0) {
+  }
+}
+object(Closure)#3 (1) {
+  ["this"]=>
+  object(Foo)#1 (0) {
+  }
+}
+object(Closure)#3 (0) {
+}