Small object + ARC tweaks.

Author: theraven

abi_version.c

@@ -137,7 +137,7 @@ PRIVATE BOOL objc_check_abi_version(struct objc_module_abi_8 *module)
 	}
 	// We can't mix GC_None and GC_Required code, but we can mix any other
 	// combination
-	FAIL_IF((gc_mode != GC_Optional) && (gc_mode != current_gc_mode),
+	FAIL_IF((gc_mode == GC_Required) && (gc_mode != current_gc_mode),
 	        "Attempting to mix GC and non-GC code!");
 	return YES;
 }

arc.m

@@ -149,7 +149,8 @@ static void cleanupPools(struct arc_tls* tls)
 
 static inline id retain(id obj)
 {
-	Class cls = classForObject(obj);
+	if (isSmallObject(obj)) { return obj; }
+	Class cls = obj->isa;
 	if ((Class)&_NSConcreteStackBlock == cls)
 	{
 		return Block_copy(obj);
@@ -165,7 +166,8 @@ static inline id retain(id obj)
 
 static inline void release(id obj)
 {
-	Class cls = classForObject(obj);
+	if (isSmallObject(obj)) { return; }
+	Class cls = obj->isa;
 	if (objc_test_class_flag(cls, objc_class_flag_fast_arc))
 	{
 		intptr_t *refCount = ((intptr_t*)obj) - 1;