Infer static for closures

Zend/Optimizer/compact_literals.c

@@ -740,6 +740,12 @@ void zend_optimizer_compact_literals(zend_op_array *op_array, zend_optimizer_ctx
 						cache_size += 2 * sizeof(void *);
 					}
 					break;
+				case ZEND_DECLARE_LAMBDA_FUNCTION:
+					if (opline->extended_value != (uint32_t)-1) {
+						opline->extended_value = cache_size;
+						cache_size += sizeof(void *);
+					}
+					break;
 			}
 			opline++;
 		}

Zend/tests/arrow_functions/005.phpt

@@ -40,8 +40,7 @@ class Test {
 
 ?>
 --EXPECT--
-object(Test)#1 (0) {
-}
+NULL
 object(Test)#1 (0) {
 }
 object(Test)#1 (0) {

Zend/tests/bug75079_2.phpt

@@ -31,6 +31,6 @@ int(123)
 
 Fatal error: Uncaught Error: Cannot access private property Foo::$bar in %s:%d
 Stack trace:
-#0 %s(%d): A->{closure:%s:%d}()
+#0 %s(%d): A::{closure:%s:%d}()
 #1 {main}
   thrown in %s on line %d

Zend/tests/closures/closure_020.phpt

@@ -28,7 +28,7 @@ object(foo)#%d (2) {
   ["test":"foo":private]=>
   int(3)
   ["a"]=>
-  object(Closure)#%d (5) {
+  object(Closure)#%d (%d) {
     ["name"]=>
     string(%d) "{closure:%s:%d}"
     ["file"]=>
@@ -40,8 +40,6 @@ object(foo)#%d (2) {
       ["a"]=>
       *RECURSION*
     }
-    ["this"]=>
-    *RECURSION*
   }
 }
 bool(true)

Zend/tests/closures/closure_026.phpt

@@ -33,15 +33,13 @@ object(foo)#%d (1) {
   ["a"]=>
   array(1) {
     [0]=>
-    object(Closure)#%d (4) {
+    object(Closure)#%d (%d) {
       ["name"]=>
       string(%d) "{closure:%s:%d}"
       ["file"]=>
       string(%d) "%s"
       ["line"]=>
       int(%d)
-      ["this"]=>
-      *RECURSION*
     }
   }
 }
@@ -50,18 +48,13 @@ int(1)
 string(1) "a"
 array(1) {
   [0]=>
-  object(Closure)#%d (4) {
+  object(Closure)#%d (%d) {
     ["name"]=>
     string(%d) "{closure:%s:%d}"
     ["file"]=>
     string(%d) "%s"
     ["line"]=>
     int(%d)
-    ["this"]=>
-    object(foo)#%d (1) {
-      ["a"]=>
-      *RECURSION*
-    }
   }
 }
 int(1)

Zend/tests/closures/closure_040.phpt

@@ -33,7 +33,5 @@ try {
 $cas->bindTo($a, 'A');
 
 ?>
---EXPECTF--
+--EXPECT--
 Closure::bindTo(): Argument #2 ($newScope) must be of type object|string|null, array given
-
-Warning: Cannot bind an instance to a static closure, this will be an error in PHP 9 in %s on line %d

Zend/tests/closures/closure_041.phpt

@@ -84,12 +84,8 @@ Warning: Cannot unbind $this of closure using $this, this will be an error in PH
 NULL
 
 After binding, with same-class instance for the bound ones
-
-Warning: Cannot bind an instance to a static closure, this will be an error in PHP 9 in %s on line %d
 scoped to A: bool(false)
 bound: A (should be scoped to dummy class)
-
-Warning: Cannot bind an instance to a static closure, this will be an error in PHP 9 in %s on line %d
 scoped to A: bool(true)
 bound: A
 After binding, with different instance for the bound ones

Zend/tests/closures/closure_043.phpt

@@ -39,7 +39,7 @@ $d = $staticScoped->bindTo(new A, 'A');
 
 echo "Done.\n";
 ?>
---EXPECTF--
+--EXPECT--
 Before binding
 bool(false)
 bool(false)
@@ -55,10 +55,6 @@ bool(false)
 bool(false)
 
 After binding, null scope, with instance
-
-Warning: Cannot bind an instance to a static closure, this will be an error in PHP 9 in %s on line %d
-
-Warning: Cannot bind an instance to a static closure, this will be an error in PHP 9 in %s on line %d
 After binding, with scope, no instance
 bool(true)
 bool(false)
@@ -67,8 +63,4 @@ bool(true)
 bool(false)
 
 After binding, with scope, with instance
-
-Warning: Cannot bind an instance to a static closure, this will be an error in PHP 9 in %s on line %d
-
-Warning: Cannot bind an instance to a static closure, this will be an error in PHP 9 in %s on line %d
 Done.

Zend/tests/closures/closure_061.phpt

@@ -157,10 +157,10 @@ bindTo(null, Cls::class):
 Success!
 
 bindTo(new Cls, null):
-Cannot bind an instance to a static closure, this will be an error in PHP 9
+Cannot rebind scope of closure created from method, this will be an error in PHP 9
 
 bindTo(new Cls, Cls::class):
-Cannot bind an instance to a static closure, this will be an error in PHP 9
+Success!
 
 bindTo(null, null):
 Cannot rebind scope of closure created from method, this will be an error in PHP 9

Zend/tests/gc/bug60139.phpt

@@ -8,7 +8,7 @@ class Foo {
     public $x;
 
     public function __construct() {
-        $this->x = function() {};
+        $this->x = function () { $this; };
     }
 }
 
@@ -17,7 +17,7 @@ class Bar {
 
     public function __construct() {
         $self = $this;
-        $this->x = function() use ($self) {};
+        $this->x = function() use ($self) { $this; };
     }
 }
 

Zend/tests/return_types/012.phpt

@@ -15,7 +15,7 @@ $baz = new foo();
 var_dump($baz->bar());
 ?>
 --EXPECTF--
-object(Closure)#%d (5) {
+object(Closure)#%d (4) {
   ["name"]=>
   string(%d) "{closure:%s:%d}"
   ["file"]=>
@@ -27,7 +27,4 @@ object(Closure)#%d (5) {
     ["test"]=>
     string(3) "one"
   }
-  ["this"]=>
-  object(foo)#%d (0) {
-  }
 }

Zend/tests/return_types/013.phpt

@@ -17,6 +17,6 @@ var_dump($func=$baz->bar(), $func());
 --EXPECTF--
 Fatal error: Uncaught TypeError: foo::{closure:%s:%d}(): Return value must be of type array, null returned in %s:%d
 Stack trace:
-#0 %s(%d): foo->{closure:%s:%d}()
+#0 %s(%d): foo::{closure:%s:%d}()
 #1 {main}
   thrown in %s on line %d

Zend/zend_closures.c

@@ -75,14 +75,19 @@ ZEND_METHOD(Closure, __invoke) /* {{{ */
 /* }}} */
 
 static bool zend_valid_closure_binding(
-		zend_closure *closure, zval *newthis, zend_class_entry *scope) /* {{{ */
+		zend_closure *closure, zval **newthis_ptr, zend_class_entry *scope) /* {{{ */
 {
+	zval *newthis = *newthis_ptr;
 	zend_function *func = &closure->func;
 	bool is_fake_closure = (func->common.fn_flags & ZEND_ACC_FAKE_CLOSURE) != 0;
 	if (newthis) {
 		if (func->common.fn_flags & ZEND_ACC_STATIC) {
-			zend_error(E_WARNING, "Cannot bind an instance to a static closure, this will be an error in PHP 9");
-			return 0;
+			// FIXME: Restrict this workaround to implicitly static closures?
+			// Will need an additional fn_flag.
+			zend_object *obj = Z_OBJ_P(newthis);
+			ZVAL_UNDEF(newthis);
+			GC_DTOR(obj);
+			*newthis_ptr = NULL;
 		}
 
 		if (is_fake_closure && func->common.scope &&
@@ -144,13 +149,14 @@ ZEND_METHOD(Closure, call)
 
 	closure = (zend_closure *) Z_OBJ_P(ZEND_THIS);
 
-	newobj = Z_OBJ_P(newthis);
-	newclass = newobj->ce;
+	newclass = Z_OBJ_P(newthis)->ce;
 
-	if (!zend_valid_closure_binding(closure, newthis, newclass)) {
+	if (!zend_valid_closure_binding(closure, &newthis, newclass)) {
 		return;
 	}
 
+	newobj = newthis ? Z_OBJ_P(newthis) : NULL;
+
 	fci_cache.called_scope = newclass;
 	fci_cache.object = fci.object = newobj;
 
@@ -241,16 +247,16 @@ static void do_closure_bind(zval *return_value, zval *zclosure, zval *newthis, z
 		ce = NULL;
 	}
 
-	if (!zend_valid_closure_binding(closure, newthis, ce)) {
-		return;
-	}
-
 	if (newthis) {
 		called_scope = Z_OBJCE_P(newthis);
 	} else {
 		called_scope = ce;
 	}
 
+	if (!zend_valid_closure_binding(closure, &newthis, ce)) {
+		return;
+	}
+
 	zend_create_closure(return_value, &closure->func, ce, called_scope, newthis);
 }
 

Zend/zend_compile.c

@@ -345,6 +345,7 @@ void zend_oparray_context_begin(zend_oparray_context *prev_context, zend_op_arra
 	CG(context).in_jmp_frameless_branch = false;
 	CG(context).active_property_info_name = NULL;
 	CG(context).active_property_hook_kind = (zend_property_hook_kind)-1;
+	CG(context).closure_may_use_this = false;
 }
 /* }}} */
 
@@ -4022,6 +4023,8 @@ static void zend_compile_dynamic_call(znode *result, znode *name_node, zend_ast
 			zend_string *method = zend_string_init(colon + 1, ZSTR_LEN(str) - (colon - ZSTR_VAL(str)) - 1, 0);
 			zend_op *opline = get_next_op();
 
+			CG(context).closure_may_use_this = true;
+
 			opline->opcode = ZEND_INIT_STATIC_METHOD_CALL;
 			opline->op1_type = IS_CONST;
 			opline->op1.constant = zend_add_class_name_literal(class);
@@ -4731,14 +4734,19 @@ static uint32_t zend_compile_frameless_icall(znode *result, zend_ast_list *args,
 static void zend_compile_ns_call(znode *result, znode *name_node, zend_ast *args_ast, uint32_t lineno, uint32_t type) /* {{{ */
 {
 	int name_constants = zend_add_ns_func_name_literal(Z_STR(name_node->u.constant));
+	zend_string *lc_func_name = Z_STR_P(CT_CONSTANT_EX(CG(active_op_array), name_constants + 2));
+
+	if (zend_string_equals_literal(lc_func_name, "call_user_func")
+	 || zend_string_equals_literal(lc_func_name, "call_user_func_array")) {
+		CG(context).closure_may_use_this = true;
+	}
 
 	/* Find frameless function with same name. */
 	zend_function *frameless_function = NULL;
 	if (args_ast->kind != ZEND_AST_CALLABLE_CONVERT
 	 && !zend_args_contain_unpack_or_named(zend_ast_get_list(args_ast))
 	 /* Avoid blowing up op count with nested frameless branches. */
 	 && !CG(context).in_jmp_frameless_branch) {
-		zend_string *lc_func_name = Z_STR_P(CT_CONSTANT_EX(CG(active_op_array), name_constants + 2));
 		frameless_function = zend_hash_find_ptr(CG(function_table), lc_func_name);
 	}
 
@@ -5166,6 +5174,7 @@ static void zend_compile_call(znode *result, zend_ast *ast, uint32_t type) /* {{
 	if (name_ast->kind != ZEND_AST_ZVAL || Z_TYPE_P(zend_ast_get_zval(name_ast)) != IS_STRING) {
 		zend_compile_expr(&name_node, name_ast);
 		zend_compile_dynamic_call(result, &name_node, args_ast, ast->lineno);
+		CG(context).closure_may_use_this = true;
 		return;
 	}
 
@@ -5198,6 +5207,9 @@ static void zend_compile_call(znode *result, zend_ast *ast, uint32_t type) /* {{
 			zend_string_release(lcname);
 			zval_ptr_dtor(&name_node.u.constant);
 			return;
+		} else if (fbc && (zend_string_equals_literal(lcname, "call_user_func")
+		  || zend_string_equals_literal(lcname, "call_user_func_array"))) {
+			CG(context).closure_may_use_this = true;
 		}
 
 		if (!fbc
@@ -5356,6 +5368,8 @@ static void zend_compile_static_call(znode *result, zend_ast *ast, uint32_t type
 		}
 	}
 
+	CG(context).closure_may_use_this = true;
+
 	opline = get_next_op();
 	opline->opcode = ZEND_INIT_STATIC_METHOD_CALL;
 
@@ -8413,6 +8427,7 @@ static zend_string *zend_begin_func_decl(znode *result, zend_op_array *op_array,
 			if (op_array->fn_flags & ZEND_ACC_CLOSURE) {
 				opline = zend_emit_op_tmp(result, ZEND_DECLARE_LAMBDA_FUNCTION, NULL, NULL);
 				opline->op2.num = func_ref;
+				opline->extended_value = (uint32_t)-1;
 			} else {
 				opline = get_next_op();
 				opline->opcode = ZEND_DECLARE_FUNCTION;
@@ -8595,6 +8610,27 @@ static zend_op_array *zend_compile_func_decl_ex(
 
 	zend_compile_stmt(stmt_ast);
 
+	if (decl->kind == ZEND_AST_CLOSURE || decl->kind == ZEND_AST_ARROW_FUNC) {
+		/* Attempt to infer static for closures that don't use $this. */
+		if (!(op_array->fn_flags & ZEND_ACC_USES_THIS)
+		 && !CG(context).closure_may_use_this
+		 && !info.varvars_used) {
+			op_array->fn_flags |= ZEND_ACC_STATIC;
+		}
+
+		zend_op_array *declaring_op_array = orig_oparray_context.op_array;
+
+		if ((op_array->fn_flags & ZEND_ACC_STATIC)
+		 && !op_array->static_variables
+		 && declaring_op_array->last) {
+			zend_op *declare_lambda_op = &declaring_op_array->opcodes[declaring_op_array->last - 1];
+			if (declare_lambda_op->opcode == ZEND_DECLARE_LAMBDA_FUNCTION) {
+				declare_lambda_op->extended_value = declaring_op_array->cache_size;
+				declaring_op_array->cache_size += sizeof(void *);
+			}
+		}
+	}
+
 	if (is_method) {
 		CG(zend_lineno) = decl->start_lineno;
 		zend_check_magic_method_implementation(
@@ -11941,6 +11977,7 @@ static void zend_compile_expr_inner(znode *result, zend_ast *ast) /* {{{ */
 			return;
 		case ZEND_AST_CLOSURE:
 		case ZEND_AST_ARROW_FUNC:
+			CG(context).closure_may_use_this = true;
 			zend_compile_func_decl(result, ast, FUNC_DECL_LEVEL_NESTED);
 			return;
 		case ZEND_AST_THROW:

Zend/zend_compile.h

@@ -208,7 +208,8 @@ typedef struct _zend_oparray_context {
 	zend_string *active_property_info_name;
 	zend_property_hook_kind active_property_hook_kind;
 	bool       in_jmp_frameless_branch;
-	bool has_assigned_to_http_response_header;
+	bool       has_assigned_to_http_response_header;
+	bool       closure_may_use_this;
 } zend_oparray_context;
 
 /* Class, property and method flags                  class|meth.|prop.|const*/