fix(blocks runtime): Optimise determination of whether something is a…

… block in ARC
gnustep · Jun 2, 2024 · 7edfecc · 7edfecc
1 parent 5e7d65c
commit 7edfecc
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Showing 4 changed files with 30 additions and 23 deletions.
diff --git a/NSBlocks.m b/NSBlocks.m
@@ -41,6 +41,7 @@ static void createNSBlockSubclass(Class superclass, Class newClass,
 	newClass->super_class = superclass;
 	newClass->name = name;
 	newClass->dtable = uninstalled_dtable;
+	newClass->info = objc_class_flag_is_block;
 
 	LOCK_RUNTIME_FOR_SCOPE();
 	objc_load_class(newClass);
@@ -66,3 +67,13 @@ BOOL objc_create_block_classes_as_subclasses_of(Class super)
 	                    objc_class_flag_permanent_instances);
 	return YES;
 }
+
+PRIVATE void init_early_blocks(void)
+{
+	if (_NSBlock.super_class != NULL) { return; }
+	_NSConcreteStackBlock.info = objc_class_flag_is_block;
+	_NSConcreteGlobalBlock.info = objc_class_flag_is_block | objc_class_flag_permanent_instances;
+	_NSConcreteMallocBlock.info = objc_class_flag_is_block;
+	_NSConcreteAutoBlock.info = objc_class_flag_is_block;
+	_NSConcreteFinalizingBlock.info = objc_class_flag_is_block;
+}
diff --git a/arc.mm b/arc.mm
@@ -325,12 +325,7 @@ static inline id retain(id obj, BOOL isWeak)
 {
 	if (isPersistentObject(obj)) { return obj; }
 	Class cls = obj->isa;
-	if ((Class)&_NSConcreteMallocBlock == cls ||
-	    (Class)&_NSConcreteStackBlock == cls ||
-		(Class)&_NSConcreteAutoBlock == cls ||
-		(Class)&_NSConcreteFinalizingBlock == cls
-		) 
-	{
+	if (UNLIKELY(objc_test_class_flag(cls, objc_class_flag_is_block))) {
 		return Block_copy(obj);
 	}
 	if (objc_test_class_flag(cls, objc_class_flag_fast_arc))
@@ -389,17 +384,15 @@ static inline void release(id obj)
 {
 	if (isPersistentObject(obj)) { return; }
 	Class cls = obj->isa;
-	if (cls == static_cast<void*>(&_NSConcreteMallocBlock) ||
-		cls == static_cast<void*>(&_NSConcreteAutoBlock) ||
-		cls == static_cast<void*>(&_NSConcreteFinalizingBlock))
+	if (UNLIKELY(objc_test_class_flag(cls, objc_class_flag_is_block)))
 	{
+		if (cls == static_cast<void*>(&_NSConcreteStackBlock))
+		{
+			return;
+		}
 		_Block_release(obj);
 		return;
 	}
-	if (cls == static_cast<void*>(&_NSConcreteStackBlock))
-	{
-		return;
-	}
 	if (objc_test_class_flag(cls, objc_class_flag_fast_arc))
 	{
 		objc_release_fast_np(obj);
@@ -871,10 +864,7 @@ static BOOL setObjectHasWeakRefs(id obj)
 		return obj;
 	}
 	Class cls = classForObject(obj);
-	if (cls == static_cast<void*>(&_NSConcreteMallocBlock) ||
-		cls == static_cast<void*>(&_NSConcreteAutoBlock) ||
-		cls == static_cast<void*>(&_NSConcreteFinalizingBlock))
-	{
+	if (UNLIKELY(objc_test_class_flag(cls, objc_class_flag_is_block))) {
 		// Check whether the block is being deallocated and return nil if so
 		if (_Block_isDeallocating(obj)) {
 			*addr = nil;
@@ -954,15 +944,14 @@ static BOOL setObjectHasWeakRefs(id obj)
 		return nil;
 	}
 	Class cls = classForObject(obj);
-	if (static_cast<void*>(&_NSConcreteMallocBlock) == cls ||
-		static_cast<void*>(&_NSConcreteAutoBlock) == cls ||
-		static_cast<void*>(&_NSConcreteFinalizingBlock) == cls) {
-		obj = static_cast<id>(block_load_weak(obj));
-	}
-	else if (objc_test_class_flag(cls, objc_class_flag_permanent_instances))
+	if (objc_test_class_flag(cls, objc_class_flag_permanent_instances))
 	{
 		return obj;
 	}
+	else if (UNLIKELY(objc_test_class_flag(cls, objc_class_flag_is_block))) {
+		obj = static_cast<id>(block_load_weak(obj));
+	}
+
 	else if (!objc_test_class_flag(cls, objc_class_flag_fast_arc))
 	{
 		obj = _objc_weak_load(obj);

diff --git a/class.h b/class.h
@@ -366,6 +366,11 @@ enum objc_class_flags
 	 * On a class, guarantees that `+init` is trivial.
 	 */
 	objc_class_flag_fast_alloc_init = (1<<15),
+	/**
+	 * The class is a block class. Reference count management must be done by
+	 * the underlying blocks runtime.
+	 */
+	objc_class_flag_is_block = (1 << 16),
 };
 
 /**

diff --git a/loader.c b/loader.c
@@ -27,6 +27,7 @@ void init_gc(void);
 void init_protocol_table(void);
 void init_selector_tables(void);
 void init_trampolines(void);
+void init_early_blocks(void);
 void objc_send_load_message(Class class);
 
 void log_selector_memory_usage(void);
@@ -76,6 +77,7 @@ static void init_runtime(void)
 		init_protocol_table();
 		init_class_tables();
 		init_alias_table();
+		init_early_blocks();
 		init_arc();
 		init_trampolines();
 		first_run = NO;