Made the selector name field into a union of the name (unregistered selectors) and the selector id / index (registered selectors), to more accurately reflect how it is used in the code.

dtable.c

@@ -28,7 +28,7 @@ static void collectMethodsForMethodListToSparseArray(
 	for (unsigned i=0 ; i<list->count ; i++)
 	{
 		//fprintf(stderr, "Adding method %s (%d)\n", sel_getName(list->methods[i].selector), PTR_TO_IDX(list->methods[i].selector->name));
-		SparseArrayInsert(sarray, PTR_TO_IDX(list->methods[i].selector->name),
+		SparseArrayInsert(sarray, list->methods[i].selector->index,
 				(void*)&list->methods[i]);
 	}
 }
@@ -197,7 +197,7 @@ static void update_dtable(dtable_t dtable)
 	uint32_t idx = 0;
 	while ((m = SparseArrayNext(methods, &idx)))
 	{
-		uint32_t idx = PTR_TO_IDX(m->selector->name);
+		uint32_t idx = m->selector->index;
 		struct slots_list *s = find_slot(idx, dtable->slots, old_slot_count);
 		if (NULL != s)
 		{
@@ -297,7 +297,7 @@ static BOOL installMethodInDtable(Class class,
                                   BOOL replaceExisting)
 {
 	assert(__objc_uninstalled_dtable != dtable);
-	uint32_t sel_id = PTR_TO_IDX(method->selector->name);
+	uint32_t sel_id = method->selector->index;
 	struct objc_slot *slot = SparseArrayLookup(dtable, sel_id);
 	if (NULL != slot)
 	{
@@ -578,7 +578,7 @@ void objc_send_initialize(id object)
 		initializeSel = sel_registerName("initialize");
 	}
 	struct objc_slot *initializeSlot = 
-		objc_dtable_lookup(dtable, PTR_TO_IDX(initializeSel->name));
+		objc_dtable_lookup(dtable, initializeSel->index);
 
 	if (0 != initializeSlot)
 	{
@@ -588,7 +588,7 @@ void objc_send_initialize(id object)
 			// is the superclass's metaclass' dtable.
 			dtable_t super_dtable = dtable_for_class(class->super_class->isa);
 			struct objc_slot *superSlot = objc_dtable_lookup(super_dtable,
-					PTR_TO_IDX(initializeSel->name));
+					initializeSel->index);
 			// Check that this IMP comes from the class, not from its
 			// superclass.  We still have to use dtable_for_class() here
 			// because our +initialize call might be in response to a message

sarray2.h

@@ -118,6 +118,4 @@ void * SparseArrayNext(SparseArray * sarray, uint32_t * index);
  */
 SparseArray *SparseArrayCopy(SparseArray * sarray);
 
-#define PTR_TO_IDX(x) ((uint32_t)(uintptr_t)x)
-
 #endif //_SARRAY_H_INCLUDED_

selector.h

@@ -22,7 +22,11 @@ struct sel_type_list
  */
 struct objc_selector
 {
-	const char * name;
+	union
+	{
+		const char *name;
+		uintptr_t index;
+	};
 	const char * types;
 };
 

selector_table.c

@@ -228,7 +228,7 @@ void __objc_init_selector_tables()
 
 static SEL selector_lookup(const char *name, const char *types)
 {
-	struct objc_selector sel = {name, types};
+	struct objc_selector sel = {{name}, types};
 	return selector_table_get(sel_table, &sel);
 }
 static inline void add_selector_to_table(SEL aSel, int32_t uid, uint32_t idx)
@@ -396,14 +396,14 @@ BOOL sel_isEqual(SEL sel1, SEL sel2)
 SEL sel_registerName(const char *selName)
 {
 	if (NULL == selName) { return NULL; }
-	struct objc_selector sel = {selName, 0};
+	struct objc_selector sel = {{selName}, 0};
 	return objc_register_selector_copy(&sel);
 }
 
 SEL sel_registerTypedName_np(const char *selName, const char *types)
 {
 	if (NULL == selName) { return NULL; }
-	struct objc_selector sel = {selName, types};
+	struct objc_selector sel = {{selName}, types};
 	return objc_register_selector_copy(&sel);
 }
 
@@ -483,7 +483,7 @@ void objc_register_selectors_from_list(struct objc_method_list *l)
 	for (int i=0 ; i<l->count ; i++)
 	{
 		Method m = &l->methods[i];
-		struct objc_selector sel = { (const char*)m->selector, m->types };
+		struct objc_selector sel = { {(const char*)m->selector}, m->types };
 		m->selector = objc_register_selector_copy(&sel);
 	}
 }

sendmsg2.c

@@ -51,7 +51,7 @@ Slot_t objc_msg_lookup_internal(id *receiver,
 {
 retry:;
 	Slot_t result = objc_dtable_lookup((*receiver)->isa->dtable,
-			PTR_TO_IDX(selector->name));
+			selector->index);
 	if (0 == result)
 	{
 		Class class = (*receiver)->isa;
@@ -61,13 +61,13 @@ retry:;
 		{
 			objc_send_initialize(*receiver);
 			dtable = dtable_for_class(class);
-			result = objc_dtable_lookup(dtable, PTR_TO_IDX(selector->name));
+			result = objc_dtable_lookup(dtable, selector->index);
 		}
 		else
 		{
 			// Check again incase another thread updated the dtable while we
 			// weren't looking
-			result = objc_dtable_lookup(dtable, PTR_TO_IDX(selector->name));
+			result = objc_dtable_lookup(dtable, selector->index);
 		}
 		if (0 == result)
 		{
@@ -147,7 +147,7 @@ Slot_t objc_slot_lookup_super(struct objc_super *super, SEL selector)
 	{
 		Class class = super->class;
 		Slot_t result = objc_dtable_lookup(dtable_for_class(class),
-				PTR_TO_IDX(selector->name));
+				selector->index);
 		if (0 == result)
 		{
 			// Dtable should always be installed in the superclass
@@ -249,7 +249,7 @@ void objc_msg_profile(id receiver, IMP method,
  */
 Slot_t objc_get_slot(Class cls, SEL selector)
 {
-	Slot_t result = objc_dtable_lookup(cls->dtable, PTR_TO_IDX(selector->name));
+	Slot_t result = objc_dtable_lookup(cls->dtable, selector->index);
 	if (0 == result)
 	{
 		void *dtable = dtable_for_class(cls);
@@ -258,13 +258,13 @@ Slot_t objc_get_slot(Class cls, SEL selector)
 		{
 			//objc_send_initialize((id)cls);
 			dtable = dtable_for_class(cls);
-			result = objc_dtable_lookup(dtable, PTR_TO_IDX(selector->name));
+			result = objc_dtable_lookup(dtable, selector->index);
 		}
 		else
 		{
 			// Check again incase another thread updated the dtable while we
 			// weren't looking
-			result = objc_dtable_lookup(dtable, PTR_TO_IDX(selector->name));
+			result = objc_dtable_lookup(dtable, selector->index);
 		}
 		if (NULL == result)
 		{