Variation of patch # 1624059 to speed up checking if an object is a subclass
of some of the common builtin types.
Use a bit in tp_flags for each common builtin type. Check the bit
to determine if any instance is a subclass of these common types.
The check avoids a function call and O(n) search of the base classes.
The check is done in the various Py*_Check macros rather than calling
PyType_IsSubtype().
All the bits are set in tp_flags when the type is declared
in the Objects/*object.c files because PyType_Ready() is not called
for all the types. Should PyType_Ready() be called for all types?
If so and the change is made, the changes to the Objects/*object.c files
can be reverted (remove setting the tp_flags). Objects/typeobject.c
would also have to be modified to add conditions
for Py*_CheckExact() in addition to each the PyType_IsSubtype check.
diff --git a/Include/tupleobject.h b/Include/tupleobject.h
index 8c37cab..738cea1 100644
--- a/Include/tupleobject.h
+++ b/Include/tupleobject.h
@@ -33,7 +33,8 @@
PyAPI_DATA(PyTypeObject) PyTuple_Type;
-#define PyTuple_Check(op) PyObject_TypeCheck(op, &PyTuple_Type)
+#define PyTuple_Check(op) \
+ PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_TUPLE_SUBCLASS)
#define PyTuple_CheckExact(op) ((op)->ob_type == &PyTuple_Type)
PyAPI_FUNC(PyObject *) PyTuple_New(Py_ssize_t size);