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bpo-41073: PyType_GetSlot() can now accept static types. (GH-21931)

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PyType_GetSlot() can now accept static types.

Co-Authored-By: Petr Viktorin <encukou@gmail.com>

Automerge-Triggered-By: GH:encukou
This commit is contained in:
Hai Shi 2020-11-11 04:53:46 +08:00 • committed by GitHub
parent ace3f9a0ce
commit a13b26cac1
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GPG key ID: 4AEE18F83AFDEB23
7 changed files with 205 additions and 101 deletions
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48
Objects/typeobject.c
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@ -56,6 +56,11 @@ static struct method_cache_entry method_cache[1 << MCACHE_SIZE_EXP];
static unsigned int next_version_tag = 0;
#endif
typedef struct PySlot_Offset {
short subslot_offset;
short slot_offset;
} PySlot_Offset;
#define MCACHE_STATS 0
#if MCACHE_STATS
@ -2870,8 +2875,18 @@ error:
return NULL;
}
static const short slotoffsets[] = {
-1, /* invalid slot */
/* An array of type slot offsets corresponding to Py_tp_* constants,
* for use in e.g. PyType_Spec and PyType_GetSlot.
* Each entry has two offsets: "slot_offset" and "subslot_offset".
* If is subslot_offset is -1, slot_offset is an offset within the
* PyTypeObject struct.
* Otherwise slot_offset is an offset to a pointer to a sub-slots struct
* (such as "tp_as_number"), and subslot_offset is the offset within
* that struct.
* The actual table is generated by a script.
*/
static const PySlot_Offset pyslot_offsets[] = {
{0, 0},
#include "typeslots.inc"
};
@ -2892,6 +2907,7 @@ PyType_FromModuleAndSpec(PyObject *module, PyType_Spec *spec, PyObject *bases)
const PyType_Slot *slot;
Py_ssize_t nmembers, weaklistoffset, dictoffset, vectorcalloffset;
char *res_start;
short slot_offset, subslot_offset;
nmembers = weaklistoffset = dictoffset = vectorcalloffset = 0;
for (slot = spec->slots; slot->slot; slot++) {
@ -3001,7 +3017,7 @@ PyType_FromModuleAndSpec(PyObject *module, PyType_Spec *spec, PyObject *bases)
for (slot = spec->slots; slot->slot; slot++) {
if (slot->slot < 0
|| (size_t)slot->slot >= Py_ARRAY_LENGTH(slotoffsets)) {
|| (size_t)slot->slot >= Py_ARRAY_LENGTH(pyslot_offsets)) {
PyErr_SetString(PyExc_RuntimeError, "invalid slot offset");
goto fail;
}
@ -3034,7 +3050,15 @@ PyType_FromModuleAndSpec(PyObject *module, PyType_Spec *spec, PyObject *bases)
}
else {
/* Copy other slots directly */
*(void**)(res_start + slotoffsets[slot->slot]) = slot->pfunc;
PySlot_Offset slotoffsets = pyslot_offsets[slot->slot];
slot_offset = slotoffsets.slot_offset;
if (slotoffsets.subslot_offset == -1) {
*(void**)((char*)res_start + slot_offset) = slot->pfunc;
} else {
void *parent_slot = *(void**)((char*)res_start + slot_offset);
subslot_offset = slotoffsets.subslot_offset;
*(void**)((char*)parent_slot + subslot_offset) = slot->pfunc;
}
}
}
if (type->tp_dealloc == NULL) {
@ -3117,15 +3141,23 @@ PyType_FromSpec(PyType_Spec *spec)
void *
PyType_GetSlot(PyTypeObject *type, int slot)
{
if (!_PyType_HasFeature(type, Py_TPFLAGS_HEAPTYPE) || slot < 0) {
void *parent_slot;
int slots_len = Py_ARRAY_LENGTH(pyslot_offsets);
if (slot <= 0 || slot >= slots_len) {
PyErr_BadInternalCall();
return NULL;
}
if ((size_t)slot >= Py_ARRAY_LENGTH(slotoffsets)) {
/* Extension module requesting slot from a future version */
parent_slot = *(void**)((char*)type + pyslot_offsets[slot].slot_offset);
if (parent_slot == NULL) {
return NULL;
}
return *(void**)(((char*)type) + slotoffsets[slot]);
/* Return slot directly if we have no sub slot. */
if (pyslot_offsets[slot].subslot_offset == -1) {
return parent_slot;
}
return *(void**)((char*)parent_slot + pyslot_offsets[slot].subslot_offset);
}
PyObject *