Move retainCount out of Object.

Going by "standard" Objective-C, retainCount really doesn't belong in
Object itself. The way GNUStep does it is to stash retainCount in memory
just below the object by allocating extra bytes for the count and returning
a pointer just beyond those extra bytes. Now Ruamoko does the same. This
fixes the inconsistencies in structure layouts for Protocol and class
structs between qfcc generated (internal) structs and user visible structs.

libs/ruamoko/rua_obj.c

@@ -1008,6 +1008,27 @@ rua_obj_msg_sendv (progs_t *pr)
 	PR_CallFunction (pr, imp);
 }
 
+static void
+rua_obj_increment_retaincount (progs_t *pr)
+{
+	pr_type_t  *obj = &P_STRUCT (pr, pr_type_t, 0);
+	R_INT (pr) = ++(*--obj).integer_var;
+}
+
+static void
+rua_obj_decrement_retaincount (progs_t *pr)
+{
+	pr_type_t  *obj = &P_STRUCT (pr, pr_type_t, 0);
+	R_INT (pr) = --(*--obj).integer_var;
+}
+
+static void
+rua_obj_get_retaincount (progs_t *pr)
+{
+	pr_type_t  *obj = &P_STRUCT (pr, pr_type_t, 0);
+	R_INT (pr) = (*--obj).integer_var;
+}
+
 static void
 rua_obj_malloc (progs_t *pr)
 {
@@ -1245,11 +1266,13 @@ rua_class_pose_as (progs_t *pr)
 static inline pr_id_t *
 class_create_instance (progs_t *pr, pr_class_t *class)
 {
-	int         size = class->instance_size * sizeof (pr_type_t);
+	int         size = (class->instance_size + 1) * sizeof (pr_type_t);
+	pr_type_t  *mem;
 	pr_id_t    *id;
 
-	id = PR_Zone_Malloc (pr, size);
-	memset (id, 0, size);
+	mem = PR_Zone_Malloc (pr, size);
+	// redundant memset (id, 0, size);
+	id = (pr_id_t *) (mem + 1);
 	id->class_pointer = PR_SetPointer (pr, class);
 	return id;
 }
@@ -1363,7 +1386,8 @@ static void
 rua_object_dispose (progs_t *pr)
 {
 	pr_id_t    *object = &P_STRUCT (pr, pr_id_t, 0);
-	PR_Zone_Free (pr, object);
+	pr_type_t  *mem = (pr_type_t *) object;
+	PR_Zone_Free (pr, mem - 1);
 }
 
 static void
@@ -1375,6 +1399,8 @@ rua_object_copy (progs_t *pr)
 
 	id = class_create_instance (pr, class);
 	memcpy (id, object, sizeof (pr_type_t) * class->instance_size);
+	// copy the retain count
+	((pr_type_t *) id)[-1] = ((pr_type_t *) object)[-1];
 	RETURN_POINTER (pr, id);
 }
 
@@ -1522,6 +1548,9 @@ static builtin_t obj_methods [] = {
 	{"obj_msg_lookup",				rua_obj_msg_lookup,				-1},
 	{"obj_msg_lookup_super",		rua_obj_msg_lookup_super,		-1},
 	{"obj_msg_sendv",				rua_obj_msg_sendv,				-1},
+	{"obj_increment_retaincount",	rua_obj_increment_retaincount,	-1},
+	{"obj_decrement_retaincount",	rua_obj_decrement_retaincount,	-1},
+	{"obj_get_retaincount",			rua_obj_get_retaincount,		-1},
 	{"obj_malloc",					rua_obj_malloc,					-1},
 	{"obj_atomic_malloc",			rua_obj_atomic_malloc,			-1},
 	{"obj_valloc",					rua_obj_valloc,					-1},

ruamoko/include/Object.h

@@ -46,7 +46,6 @@
 @interface Object <Object>
 {
 	Class		isa;
-	unsigned	retainCount;
 }
 
 + (id) alloc;

ruamoko/include/runtime.h

@@ -28,6 +28,8 @@ typedef enum {
 @extern IMP obj_msg_lookup (id receiver, SEL op);
 @extern IMP obj_msg_lookup_super (Super class, SEL op);
 @extern @param obj_msg_sendv (id receiver, SEL op, @va_list args);
+@extern BOOL obj_decrement_ref_was_zero (id object);
+@extern BOOL obj_increment_ref_was_zero (id object);
 @extern void *obj_malloc (int size);
 @extern void *obj_atomic_malloc (int size);
 @extern void *obj_valloc (int size);

ruamoko/lib/Object.r

@@ -10,6 +10,9 @@ IMP (Super class, SEL op) obj_msg_lookup_super = #0;
 id (id receiver, SEL op, ...) obj_msgSend = #0;
 id obj_msgSend_super (Super *class, SEL op, ...) = #0;
 @param (id receiver, SEL op, @va_list args) obj_msg_sendv = #0;
+int obj_decrement_retaincount (id object) = #0;
+int obj_increment_retaincount (id object) = #0;
+int obj_get_retaincount (id object) = #0;
 void *obj_malloc (int size) = #0;
 void *obj_atomic_malloc (int size) = #0;
 void *obj_valloc (int size) = #0;
@@ -149,8 +152,7 @@ BOOL (id object) object_is_meta_class = #0;
 
 - (id) init
 {
-	retainCount = 1;
-
+	[self retain];
 	return self;
 }
 
@@ -282,16 +284,16 @@ BOOL (id object) object_is_meta_class = #0;
 */
 - (id) retain
 {
-	retainCount = [self retainCount] + 1;
+	obj_increment_retaincount (self);
 	return self;
 }
 
 - (/*oneway*/ void) release
 {
-	if ([self retainCount] == 1)	// don't let retain count actually reach zero
+	if ([self retainCount] == 1)	// don't let retain count reach zero
 		[self dealloc];
 	else
-		retainCount--;
+		obj_decrement_retaincount (self);
 }
 
 - (id) autorelease
@@ -302,7 +304,7 @@ BOOL (id object) object_is_meta_class = #0;
 
 - (unsigned) retainCount
 {
-	return retainCount;
+	return obj_get_retaincount (self);
 }
 /*
 	CONVENIENCE METHODS