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Major speedup for new-style class creation. Turns out there was some

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trampolining going on with the tp_new descriptor, where the inherited
PyType_GenericNew was overwritten with the much slower slot_tp_new
which would end up calling tp_new_wrapper which would eventually call
PyType_GenericNew.  Add a special case for this to update_one_slot().

XXX Hope there isn't a loophole in this.  I'll buy the first person to
point out a bug in the reasoning a beer.

Backport candidate (but I won't do it).
This commit is contained in:
Guido van Rossum 2002-08-09 02:14:34 +00:00
parent c35491ee3a
commit 721f62e200
1 changed files with 22 additions and 0 deletions
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22
Objects/typeobject.c
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@ -4081,6 +4081,28 @@ update_one_slot(PyTypeObject *type, slotdef *p)
use_generic = 1; use_generic = 1;
} }
} }
else if (descr->ob_type == &PyCFunction_Type &&
PyCFunction_GET_FUNCTION(descr) ==
(PyCFunction)tp_new_wrapper &&
strcmp(p->name, "__new__") == 0)
{
/* The __new__ wrapper is not a wrapper descriptor,
so must be special-cased differently.
If we don't do this, creating an instance will
always use slot_tp_new which will look up
__new__ in the MRO which will call tp_new_wrapper
which will look through the base classes looking
for a static base and call its tp_new (usually
PyType_GenericNew), after performing various
sanity checks and constructing a new argument
list. Cut all that nonsense short -- this speeds
up instance creation tremendously. */
specific = type->tp_new;
/* XXX I'm not 100% sure that there isn't a hole
in this reasoning that requires additional
sanity checks. I'll buy the first person to
point out a bug in this reasoning a beer. */
}
else { else {
use_generic = 1; use_generic = 1;
generic = p->function; generic = p->function;