Provide quick access to Object ancestry

Author: lawnjelly

core/object.cpp

@@ -1937,6 +1937,7 @@ Object::Object() {
 	_can_translate = true;
 	_is_queued_for_deletion = false;
 	_emitting = false;
+	_ancestry = 0;
 	memset(_script_instance_bindings, 0, sizeof(void *) * MAX_SCRIPT_INSTANCE_BINDINGS);
 	script_instance = nullptr;
 	_rc.store(nullptr, std::memory_order_release);

core/object.h

@@ -428,6 +428,16 @@ class Object {
 		CONNECT_REFERENCE_COUNTED = 8,
 	};
 
+	// Store on each object a bitfield to quickly test whether it is derived from some "key" classes
+	// that are commonly tested in performance sensitive code.
+	// Ensure unsigned to bitpack.
+	enum class AncestralClass : unsigned int {
+		REFERENCE = 1 << 0,
+		SPATIAL = 1 << 1,
+		CANVAS_ITEM = 1 << 2,
+		VISUAL_INSTANCE = 1 << 3
+	};
+
 	struct Connection {
 		Object *source;
 		StringName signal;
@@ -491,20 +501,24 @@ class Object {
 #ifdef DEBUG_ENABLED
 	SafeRefCount _lock_index;
 #endif
-	bool _block_signals;
 	int _predelete_ok;
 	Set<Object *> change_receptors;
 	ObjectID _instance_id;
 	std::atomic<ObjectRC *> _rc;
-	bool _predelete();
-	void _postinitialize();
-	bool _can_translate;
-	bool _emitting;
+
+	uint32_t _ancestry : 4;
+	bool _block_signals : 1;
+	bool _can_translate : 1;
+	bool _emitting : 1;
 #ifdef TOOLS_ENABLED
-	bool _edited;
+	bool _edited : 1;
 	uint32_t _edited_version;
 	Set<String> editor_section_folding;
 #endif
+
+	bool _predelete();
+	void _postinitialize();
+
 	ScriptInstance *script_instance;
 	RefPtr script;
 	Dictionary metadata;
@@ -586,6 +600,7 @@ class Object {
 	virtual void _validate_property(PropertyInfo &property) const;
 
 	void _disconnect(const StringName &p_signal, Object *p_to_object, const StringName &p_to_method, bool p_force = false);
+	void _define_ancestry(AncestralClass p_class) { _ancestry |= (uint32_t)p_class; }
 
 public: //should be protected, but bug in clang++
 	static void initialize_class();
@@ -660,6 +675,8 @@ class Object {
 	virtual bool is_class(const String &p_class) const { return (p_class == "Object"); }
 	virtual bool is_class_ptr(void *p_ptr) const { return get_class_ptr_static() == p_ptr; }
 
+	bool has_ancestry(AncestralClass p_class) const { return _ancestry & (uint32_t)p_class; }
+
 	_FORCE_INLINE_ const StringName &get_class_name() const {
 		if (!_class_ptr) {
 			return *_get_class_namev();

core/reference.cpp

@@ -97,6 +97,7 @@ bool Reference::unreference() {
 }
 
 Reference::Reference() {
+	_define_ancestry(AncestralClass::REFERENCE);
 	refcount.init();
 	refcount_init.init();
 }

core/variant.cpp

@@ -2160,9 +2160,9 @@ Variant::Variant(const Object *p_object) {
 	Object *obj = const_cast<Object *>(p_object);
 
 	memnew_placement(_data._mem, ObjData);
-	Reference *ref = Object::cast_to<Reference>(obj);
-	if (unlikely(ref)) {
-		*reinterpret_cast<Ref<Reference> *>(_get_obj().ref.get_data()) = Ref<Reference>(ref);
+
+	if (obj && obj->has_ancestry(Object::AncestralClass::REFERENCE)) {
+		*reinterpret_cast<Ref<Reference> *>(_get_obj().ref.get_data()) = Ref<Reference>((Reference *)obj);
 		_get_obj().rc = nullptr;
 	} else {
 		_get_obj().rc = likely(obj) ? obj->_use_rc() : nullptr;

scene/2d/canvas_item.cpp

@@ -1346,6 +1346,8 @@ int CanvasItem::get_canvas_layer() const {
 
 CanvasItem::CanvasItem() :
 		xform_change(this) {
+	_define_ancestry(AncestralClass::CANVAS_ITEM);
+
 	canvas_item = RID_PRIME(VisualServer::get_singleton()->canvas_item_create());
 	visible = true;
 	pending_update = false;

scene/3d/spatial.cpp

@@ -1248,6 +1248,8 @@ void Spatial::_bind_methods() {
 
 Spatial::Spatial() :
 		xform_change(this), _client_physics_interpolation_spatials_list(this) {
+	_define_ancestry(AncestralClass::SPATIAL);
+
 	data.dirty = DIRTY_NONE;
 	data.children_lock = 0;
 

scene/3d/visual_instance.cpp

@@ -208,6 +208,8 @@ RID VisualInstance::get_base() const {
 }
 
 VisualInstance::VisualInstance() {
+	_define_ancestry(AncestralClass::VISUAL_INSTANCE);
+
 	instance = RID_PRIME(VisualServer::get_singleton()->instance_create());
 	VisualServer::get_singleton()->instance_attach_object_instance_id(instance, get_instance_id());
 	layers = 1;