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bpo-40170: PyType_HasFeature() no longer acccess directly tp_flags #19378

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Merged
merged 1 commit into from
Apr 7, 2020
Merged

bpo-40170: PyType_HasFeature() no longer acccess directly tp_flags #19378

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11 changes: 10 additions & 1 deletion Include/internal/pycore_object.h
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Original file line number Diff line number Diff line change
Expand Up @@ -8,7 +8,7 @@ extern "C" {
# error "this header requires Py_BUILD_CORE define"
#endif

#include "pycore_pystate.h" /* _PyRuntime.gc */
#include "pycore_pystate.h" /* PyInterpreterState.gc */

PyAPI_FUNC(int) _PyType_CheckConsistency(PyTypeObject *type);
PyAPI_FUNC(int) _PyDict_CheckConsistency(PyObject *mp, int check_content);
Expand Down Expand Up @@ -94,6 +94,15 @@ _PyObject_GET_WEAKREFS_LISTPTR(PyObject *op)
return (PyObject **)((char *)op + offset);
}

// Fast inlined version of PyType_HasFeature()
static inline int
_PyType_HasFeature(PyTypeObject *type, unsigned long feature) {
return ((type->tp_flags & feature) != 0);
}

// Fast inlined version of PyType_IS_GC()
#define _PyType_IS_GC(t) _PyType_HasFeature((t), Py_TPFLAGS_HAVE_GC)

#ifdef __cplusplus
}
#endif
Expand Down
4 changes: 0 additions & 4 deletions Include/object.h
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Expand Up @@ -614,11 +614,7 @@ times.

static inline int
PyType_HasFeature(PyTypeObject *type, unsigned long feature) {
#ifdef Py_LIMITED_API
return ((PyType_GetFlags(type) & feature) != 0);
#else
return ((type->tp_flags & feature) != 0);
#endif
}

#define PyType_FastSubclass(type, flag) PyType_HasFeature(type, flag)
Expand Down
4 changes: 4 additions & 0 deletions Misc/NEWS.d/next/C API/2020-04-05-00-21-38.bpo-40170.Tx0vy6.rst
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@@ -0,0 +1,4 @@
:c:func:`PyType_HasFeature` now always calls :c:func:`PyType_GetFlags` to
hide implementation details. Previously, it accessed directly the
:c:member:`PyTypeObject.tp_flags` member when the limited C API was not
used.
10 changes: 5 additions & 5 deletions Objects/object.c
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Expand Up @@ -187,11 +187,11 @@ PyObject_CallFinalizer(PyObject *self)
if (tp->tp_finalize == NULL)
return;
/* tp_finalize should only be called once. */
if (PyType_IS_GC(tp) && _PyGC_FINALIZED(self))
if (_PyType_IS_GC(tp) && _PyGC_FINALIZED(self))
return;

tp->tp_finalize(self);
if (PyType_IS_GC(tp)) {
if (_PyType_IS_GC(tp)) {
_PyGC_SET_FINALIZED(self);
}
}
Expand Down Expand Up @@ -228,7 +228,7 @@ PyObject_CallFinalizerFromDealloc(PyObject *self)
Py_SET_REFCNT(self, refcnt);

_PyObject_ASSERT(self,
(!PyType_IS_GC(Py_TYPE(self))
(!_PyType_IS_GC(Py_TYPE(self))
|| _PyObject_GC_IS_TRACKED(self)));
/* If Py_REF_DEBUG macro is defined, _Py_NewReference() increased
_Py_RefTotal, so we need to undo that. */
Expand Down Expand Up @@ -1103,7 +1103,7 @@ _PyObject_GetMethod(PyObject *obj, PyObject *name, PyObject **method)
descr = _PyType_Lookup(tp, name);
if (descr != NULL) {
Py_INCREF(descr);
if (PyType_HasFeature(Py_TYPE(descr), Py_TPFLAGS_METHOD_DESCRIPTOR)) {
if (_PyType_HasFeature(Py_TYPE(descr), Py_TPFLAGS_METHOD_DESCRIPTOR)) {
meth_found = 1;
} else {
f = Py_TYPE(descr)->tp_descr_get;
Expand Down Expand Up @@ -2176,7 +2176,7 @@ _PyObject_AssertFailed(PyObject *obj, const char *expr, const char *msg,
to crash than dumping the traceback. */
void *ptr;
PyTypeObject *type = Py_TYPE(obj);
if (PyType_IS_GC(type)) {
if (_PyType_IS_GC(type)) {
ptr = (void *)((char *)obj - sizeof(PyGC_Head));
}
else {
Expand Down
47 changes: 27 additions & 20 deletions Objects/typeobject.c
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Expand Up @@ -269,7 +269,7 @@ PyType_Modified(PyTypeObject *type)
PyObject *raw, *ref;
Py_ssize_t i;

if (!PyType_HasFeature(type, Py_TPFLAGS_VALID_VERSION_TAG))
if (!_PyType_HasFeature(type, Py_TPFLAGS_VALID_VERSION_TAG))
return;

raw = type->tp_subclasses;
Expand Down Expand Up @@ -307,7 +307,7 @@ type_mro_modified(PyTypeObject *type, PyObject *bases) {
PyObject *mro_meth = NULL;
PyObject *type_mro_meth = NULL;

if (!PyType_HasFeature(type, Py_TPFLAGS_HAVE_VERSION_TAG))
if (!_PyType_HasFeature(type, Py_TPFLAGS_HAVE_VERSION_TAG))
return;

if (custom) {
Expand All @@ -332,7 +332,7 @@ type_mro_modified(PyTypeObject *type, PyObject *bases) {
assert(PyType_Check(b));
cls = (PyTypeObject *)b;

if (!PyType_HasFeature(cls, Py_TPFLAGS_HAVE_VERSION_TAG) ||
if (!_PyType_HasFeature(cls, Py_TPFLAGS_HAVE_VERSION_TAG) ||
!PyType_IsSubtype(type, cls)) {
goto clear;
}
Expand All @@ -356,11 +356,11 @@ assign_version_tag(PyTypeObject *type)
Py_ssize_t i, n;
PyObject *bases;

if (PyType_HasFeature(type, Py_TPFLAGS_VALID_VERSION_TAG))
if (_PyType_HasFeature(type, Py_TPFLAGS_VALID_VERSION_TAG))
return 1;
if (!PyType_HasFeature(type, Py_TPFLAGS_HAVE_VERSION_TAG))
if (!_PyType_HasFeature(type, Py_TPFLAGS_HAVE_VERSION_TAG))
return 0;
if (!PyType_HasFeature(type, Py_TPFLAGS_READY))
if (!_PyType_HasFeature(type, Py_TPFLAGS_READY))
return 0;

type->tp_version_tag = next_version_tag++;
Expand Down Expand Up @@ -1028,23 +1028,29 @@ PyType_GenericAlloc(PyTypeObject *type, Py_ssize_t nitems)
const size_t size = _PyObject_VAR_SIZE(type, nitems+1);
/* note that we need to add one, for the sentinel */

if (PyType_IS_GC(type))
if (_PyType_IS_GC(type)) {
obj = _PyObject_GC_Malloc(size);
else
}
else {
obj = (PyObject *)PyObject_MALLOC(size);
}

if (obj == NULL)
if (obj == NULL) {
return PyErr_NoMemory();
}

memset(obj, '\0', size);

if (type->tp_itemsize == 0)
if (type->tp_itemsize == 0) {
(void)PyObject_INIT(obj, type);
else
}
else {
(void) PyObject_INIT_VAR((PyVarObject *)obj, type, nitems);
}

if (PyType_IS_GC(type))
if (_PyType_IS_GC(type)) {
_PyObject_GC_TRACK(obj);
}
return obj;
}

Expand Down Expand Up @@ -1178,7 +1184,7 @@ subtype_dealloc(PyObject *self)

/* Test whether the type has GC exactly once */

if (!PyType_IS_GC(type)) {
if (!_PyType_IS_GC(type)) {
/* A non GC dynamic type allows certain simplifications:
there's no need to call clear_slots(), or DECREF the dict,
or clear weakrefs. */
Expand Down Expand Up @@ -1304,8 +1310,9 @@ subtype_dealloc(PyObject *self)
/* Call the base tp_dealloc(); first retrack self if
* basedealloc knows about gc.
*/
if (PyType_IS_GC(base))
if (_PyType_IS_GC(base)) {
_PyObject_GC_TRACK(self);
}
assert(basedealloc);
basedealloc(self);

Expand Down Expand Up @@ -1435,7 +1442,7 @@ lookup_maybe_method(PyObject *self, _Py_Identifier *attrid, int *unbound)
return NULL;
}

if (PyType_HasFeature(Py_TYPE(res), Py_TPFLAGS_METHOD_DESCRIPTOR)) {
if (_PyType_HasFeature(Py_TYPE(res), Py_TPFLAGS_METHOD_DESCRIPTOR)) {
/* Avoid temporary PyMethodObject */
*unbound = 1;
Py_INCREF(res);
Expand Down Expand Up @@ -2026,7 +2033,7 @@ best_base(PyObject *bases)
if (PyType_Ready(base_i) < 0)
return NULL;
}
if (!PyType_HasFeature(base_i, Py_TPFLAGS_BASETYPE)) {
if (!_PyType_HasFeature(base_i, Py_TPFLAGS_BASETYPE)) {
PyErr_Format(PyExc_TypeError,
"type '%.100s' is not an acceptable base type",
base_i->tp_name);
Expand Down Expand Up @@ -2933,7 +2940,7 @@ PyType_FromSpecWithBases(PyType_Spec *spec, PyObject *bases)
if (base == NULL) {
goto fail;
}
if (!PyType_HasFeature(base, Py_TPFLAGS_BASETYPE)) {
if (!_PyType_HasFeature(base, Py_TPFLAGS_BASETYPE)) {
PyErr_Format(PyExc_TypeError,
"type '%.100s' is not an acceptable base type",
base->tp_name);
Expand Down Expand Up @@ -3051,7 +3058,7 @@ PyType_FromSpec(PyType_Spec *spec)
void *
PyType_GetSlot(PyTypeObject *type, int slot)
{
if (!PyType_HasFeature(type, Py_TPFLAGS_HEAPTYPE) || slot < 0) {
if (!_PyType_HasFeature(type, Py_TPFLAGS_HEAPTYPE) || slot < 0) {
PyErr_BadInternalCall();
return NULL;
}
Expand Down Expand Up @@ -3134,7 +3141,7 @@ _PyType_Lookup(PyTypeObject *type, PyObject *name)
unsigned int h;

if (MCACHE_CACHEABLE_NAME(name) &&
PyType_HasFeature(type, Py_TPFLAGS_VALID_VERSION_TAG)) {
_PyType_HasFeature(type, Py_TPFLAGS_VALID_VERSION_TAG)) {
/* fast path */
h = MCACHE_HASH_METHOD(type, name);
if (method_cache[h].version == type->tp_version_tag &&
Expand Down Expand Up @@ -5404,7 +5411,7 @@ PyType_Ready(PyTypeObject *type)
}

/* Sanity check for tp_free. */
if (PyType_IS_GC(type) && (type->tp_flags & Py_TPFLAGS_BASETYPE) &&
if (_PyType_IS_GC(type) && (type->tp_flags & Py_TPFLAGS_BASETYPE) &&
(type->tp_free == NULL || type->tp_free == PyObject_Del)) {
/* This base class needs to call tp_free, but doesn't have
* one, or its tp_free is for non-gc'ed objects.
Expand Down