Add interfaces for better integration with Foundation.

arc.m

@@ -175,17 +175,8 @@ static const long weak_mask = ((size_t)1)<<((sizeof(size_t)*8)-1);
  */
 static const long refcount_mask = ~weak_mask;
 
-static inline id retain(id obj)
+id objc_retain_fast_np(id obj)
 {
-	if (isSmallObject(obj)) { return obj; }
-	Class cls = obj->isa;
-	if ((Class)&_NSConcreteMallocBlock == cls ||
-	    (Class)&_NSConcreteStackBlock == cls)
-	{
-		return Block_copy(obj);
-	}
-	if (objc_test_class_flag(cls, objc_class_flag_fast_arc))
-	{
 	uintptr_t *refCount = ((uintptr_t*)obj) - 1;
 	uintptr_t refCountVal = __sync_fetch_and_add(refCount, 0);
 	uintptr_t newVal = refCountVal;
@@ -221,26 +212,26 @@ static inline id retain(id obj)
 		newVal = __sync_val_compare_and_swap(refCount, refCountVal, updated);
 	} while (newVal != refCountVal);
 	return obj;
-	}
-	return [obj retain];
 }
 
-static inline void release(id obj)
+static inline id retain(id obj)
 {
-	if (isSmallObject(obj)) { return; }
+	if (isSmallObject(obj)) { return obj; }
 	Class cls = obj->isa;
-	if (cls == &_NSConcreteMallocBlock)
+	if ((Class)&_NSConcreteMallocBlock == cls ||
-	{
+	    (Class)&_NSConcreteStackBlock == cls)
-		_Block_release(obj);
-		return;
-	}
-	if ((cls == &_NSConcreteStackBlock) ||
-	    (cls == &_NSConcreteGlobalBlock))
 	{
-		return;
+		return Block_copy(obj);
 	}
 	if (objc_test_class_flag(cls, objc_class_flag_fast_arc))
 	{
+		return objc_retain_fast_np(obj);
+	}
+	return [obj retain];
+}
+
+BOOL objc_release_fast_no_destroy_np(id obj)
+{
 	uintptr_t *refCount = ((uintptr_t*)obj) - 1;
 	uintptr_t refCountVal = __sync_fetch_and_add(refCount, 0);
 	uintptr_t newVal = refCountVal;
@@ -252,7 +243,7 @@ static inline void release(id obj)
 		// If the reference count is saturated, don't decrement it.
 		if (realCount == refcount_mask)
 		{
-				return;
+			return NO;
 		}
 		realCount--;
 		isWeak = (refCountVal & weak_mask) == weak_mask;
@@ -269,11 +260,39 @@ static inline void release(id obj)
 		{
 			if (!objc_delete_weak_refs(obj))
 			{
-					return;
+				return NO;
+			}
 		}
+		return YES;
 	}
+	return NO;
+}
+
+void objc_release_fast_np(id obj)
+{
+	if (objc_release_fast_no_destroy_np(obj))
+	{
 		[obj dealloc];
 	}
+}
+
+static inline void release(id obj)
+{
+	if (isSmallObject(obj)) { return; }
+	Class cls = obj->isa;
+	if (cls == &_NSConcreteMallocBlock)
+	{
+		_Block_release(obj);
+		return;
+	}
+	if ((cls == &_NSConcreteStackBlock) ||
+	    (cls == &_NSConcreteGlobalBlock))
+	{
+		return;
+	}
+	if (objc_test_class_flag(cls, objc_class_flag_fast_arc))
+	{
+		objc_release_fast_np(obj);
 		return;
 	}
 	[obj release];
@@ -375,7 +394,6 @@ unsigned long objc_arc_autorelease_count_for_object_np(id obj)
 	return count;
 }
 
-
 void *objc_autoreleasePoolPush(void)
 {
 	initAutorelease();

objc/objc-arc.h

@@ -32,6 +32,12 @@ id objc_loadWeakRetained(id* obj);
  * Retains the argument.  Equivalent to [obj retain].
  */
 id objc_retain(id obj);
+/**
+ * Retains the argument, assuming that the argument is a normal object and has
+ * its reference count managed by the runtime.
+ * This is intended to implement `-retain` in ARC-compatible root classes.
+ */
+id objc_retain_fast_np(id obj) OBJC_NONPORTABLE;
 /**
  * Retains and autoreleases an object.  Equivalent to [[obj retain] autorelease].
  */
@@ -85,6 +91,26 @@ void objc_destroyWeak(id* addr);
  * Equivalent to objc_copyWeak(), but may also set src to nil.
  */
 void objc_moveWeak(id *dest, id *src);
+/**
+ * Releases the argument, assuming that the argument is a normal object and has
+ * its reference count managed by the runtime.  If the retain count reaches
+ * zero then all weak references will be zeroed and the object will be
+ * destroyed.
+ *
+ * This is intended to implement `-release` in ARC-compatible root
+ * classes.
+ */
+void objc_release_fast_np(id obj) OBJC_NONPORTABLE;
+/**
+ * Releases the argument, assuming that the argument is a normal object and has
+ * its reference count managed by the runtime.  If the retain count reaches
+ * zero then all weak references will be zeroed but the object will *NOT* be
+ * destroyed.
+ *
+ * This is intended to implement `NSDecrementExtraRefCountWasZero` for use with
+ * ARC-compatible classes.
+ */
+BOOL objc_release_fast_no_destroy_np(id obj) OBJC_NONPORTABLE;
 /**
  * Releases an object.  Equivalent to [obj release].
  */