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/Objects/typeobject.c b/Objects/typeobject.c
index 20b530c..4b0816e 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -2288,7 +2288,7 @@
(setattrofunc)type_setattro, /* tp_setattro */
0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
- Py_TPFLAGS_BASETYPE, /* tp_flags */
+ Py_TPFLAGS_BASETYPE | Py_TPFLAGS_TYPE_SUBCLASS, /* tp_flags */
type_doc, /* tp_doc */
(traverseproc)type_traverse, /* tp_traverse */
(inquiry)type_clear, /* tp_clear */
@@ -2967,6 +2967,26 @@
if (type->tp_flags & base->tp_flags & Py_TPFLAGS_HAVE_CLASS) {
COPYVAL(tp_dictoffset);
}
+
+ /* Setup fast subclass flags */
+ if (PyType_IsSubtype(base, (PyTypeObject*)PyExc_BaseException))
+ type->tp_flags |= Py_TPFLAGS_BASE_EXC_SUBCLASS;
+ else if (PyType_IsSubtype(base, &PyType_Type))
+ type->tp_flags |= Py_TPFLAGS_TYPE_SUBCLASS;
+ else if (PyType_IsSubtype(base, &PyInt_Type))
+ type->tp_flags |= Py_TPFLAGS_INT_SUBCLASS;
+ else if (PyType_IsSubtype(base, &PyLong_Type))
+ type->tp_flags |= Py_TPFLAGS_LONG_SUBCLASS;
+ else if (PyType_IsSubtype(base, &PyString_Type))
+ type->tp_flags |= Py_TPFLAGS_STRING_SUBCLASS;
+ else if (PyType_IsSubtype(base, &PyUnicode_Type))
+ type->tp_flags |= Py_TPFLAGS_UNICODE_SUBCLASS;
+ else if (PyType_IsSubtype(base, &PyTuple_Type))
+ type->tp_flags |= Py_TPFLAGS_TUPLE_SUBCLASS;
+ else if (PyType_IsSubtype(base, &PyList_Type))
+ type->tp_flags |= Py_TPFLAGS_LIST_SUBCLASS;
+ else if (PyType_IsSubtype(base, &PyDict_Type))
+ type->tp_flags |= Py_TPFLAGS_DICT_SUBCLASS;
}
static void