bpo-36974: Make tp_call=PyVectorcall_Call work for inherited types (GH-13699)

When inheriting a heap subclass from a vectorcall class that sets
`.tp_call=PyVectorcall_Call` (as recommended in PEP 590), the subclass does
not inherit `_Py_TPFLAGS_HAVE_VECTORCALL`, and thus `PyVectorcall_Call` does
not work for it.

This attempts to solve the issue by:
* always inheriting `tp_vectorcall_offset` unless `tp_call` is overridden
  in the subclass
* inheriting _Py_TPFLAGS_HAVE_VECTORCALL for static types, unless `tp_call`
  is overridden
* making `PyVectorcall_Call` ignore `_Py_TPFLAGS_HAVE_VECTORCALL`

This means it'll be ever more important to only call `PyVectorcall_Call`
on classes that support vectorcall. In `PyVectorcall_Call`'s intended role
as `tp_call` filler, that's not a problem.
This commit is contained in:
Petr Viktorin 2019-06-02 23:52:20 +02:00 committed by GitHub
parent e1179a5096
commit fb9423fd0a
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GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 51 additions and 17 deletions

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@ -515,9 +515,10 @@ class TestPEP590(unittest.TestCase):
def test_vectorcall(self):
# Test a bunch of different ways to call objects:
# 1. normal call
# 2. vectorcall using _PyObject_Vectorcall()
# 3. vectorcall using PyVectorcall_Call()
# 1. vectorcall using PyVectorcall_Call()
# (only for objects that support vectorcall directly)
# 2. normal call
# 3. vectorcall using _PyObject_Vectorcall()
# 4. call as bound method
# 5. call using functools.partial
@ -541,6 +542,27 @@ class TestPEP590(unittest.TestCase):
kwnames = tuple(kwargs)
return pyobject_vectorcall(func, args, kwnames)
for (func, args, kwargs, expected) in calls:
with self.subTest(str(func)):
if not kwargs:
self.assertEqual(expected, pyvectorcall_call(func, args))
self.assertEqual(expected, pyvectorcall_call(func, args, kwargs))
# Add derived classes (which do not support vectorcall directly,
# but do support all other ways of calling).
class MethodDescriptorHeap(_testcapi.MethodDescriptorBase):
pass
class MethodDescriptorOverridden(_testcapi.MethodDescriptorBase):
def __call__(self, n):
return 'new'
calls += [
(MethodDescriptorHeap(), (0,), {}, True),
(MethodDescriptorOverridden(), (0,), {}, 'new'),
]
for (func, args, kwargs, expected) in calls:
with self.subTest(str(func)):
args1 = args[1:]
@ -549,12 +571,10 @@ class TestPEP590(unittest.TestCase):
if not kwargs:
self.assertEqual(expected, func(*args))
self.assertEqual(expected, pyobject_vectorcall(func, args, None))
self.assertEqual(expected, pyvectorcall_call(func, args))
self.assertEqual(expected, meth(*args1))
self.assertEqual(expected, wrapped(*args))
self.assertEqual(expected, func(*args, **kwargs))
self.assertEqual(expected, vectorcall(func, args, kwargs))
self.assertEqual(expected, pyvectorcall_call(func, args, kwargs))
self.assertEqual(expected, meth(*args1, **kwargs))
self.assertEqual(expected, wrapped(*args, **kwargs))

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@ -5854,7 +5854,7 @@ MethodDescriptor_vectorcall(PyObject *callable, PyObject *const *args,
static PyObject *
MethodDescriptor_new(PyTypeObject* type, PyObject* args, PyObject *kw)
{
MethodDescriptorObject *op = PyObject_New(MethodDescriptorObject, type);
MethodDescriptorObject *op = type->tp_alloc(type, 0);
op->vectorcall = MethodDescriptor_vectorcall;
return (PyObject *)op;
}

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@ -173,12 +173,22 @@ _PyObject_MakeTpCall(PyObject *callable, PyObject *const *args, Py_ssize_t nargs
PyObject *
PyVectorcall_Call(PyObject *callable, PyObject *tuple, PyObject *kwargs)
{
vectorcallfunc func = _PyVectorcall_Function(callable);
/* get vectorcallfunc as in _PyVectorcall_Function, but without
* the _Py_TPFLAGS_HAVE_VECTORCALL check */
Py_ssize_t offset = Py_TYPE(callable)->tp_vectorcall_offset;
if ((offset <= 0) || (!Py_TYPE(callable)->tp_call)) {
PyErr_Format(PyExc_TypeError, "'%.200s' object does not support vectorcall",
Py_TYPE(callable)->tp_name);
return NULL;
}
vectorcallfunc func = *(vectorcallfunc *)(((char *)callable) + offset);
if (func == NULL) {
PyErr_Format(PyExc_TypeError, "'%.200s' object does not support vectorcall",
Py_TYPE(callable)->tp_name);
return NULL;
}
/* Convert arguments & call */
PyObject *const *args;
Py_ssize_t nargs = PyTuple_GET_SIZE(tuple);
PyObject *kwnames;

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@ -5145,17 +5145,21 @@ inherit_slots(PyTypeObject *type, PyTypeObject *base)
}
COPYSLOT(tp_repr);
/* tp_hash see tp_richcompare */
COPYSLOT(tp_call);
/* Inherit tp_vectorcall_offset and _Py_TPFLAGS_HAVE_VECTORCALL if tp_call
* was inherited, but only for extension types */
if ((base->tp_flags & _Py_TPFLAGS_HAVE_VECTORCALL) &&
!(type->tp_flags & _Py_TPFLAGS_HAVE_VECTORCALL) &&
!(type->tp_flags & Py_TPFLAGS_HEAPTYPE) &&
base->tp_call &&
type->tp_call == base->tp_call)
{
type->tp_vectorcall_offset = base->tp_vectorcall_offset;
type->tp_flags |= _Py_TPFLAGS_HAVE_VECTORCALL;
/* Inherit tp_vectorcall_offset only if tp_call is not overridden */
if (!type->tp_call) {
COPYSLOT(tp_vectorcall_offset);
}
/* Inherit_Py_TPFLAGS_HAVE_VECTORCALL for non-heap types
* if tp_call is not overridden */
if (!type->tp_call &&
(base->tp_flags & _Py_TPFLAGS_HAVE_VECTORCALL) &&
!(type->tp_flags & _Py_TPFLAGS_HAVE_VECTORCALL) &&
!(type->tp_flags & Py_TPFLAGS_HEAPTYPE))
{
type->tp_flags |= _Py_TPFLAGS_HAVE_VECTORCALL;
}
COPYSLOT(tp_call);
}
COPYSLOT(tp_str);
{