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corona10corona10
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pythongh-116621: Set manual critical section for list.extend (pythongh-116657)
1 parent 1261866 commit 3325699

2 files changed

Lines changed: 97 additions & 64 deletions

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‎Objects/clinic/listobject.c.h‎

Lines changed: 4 additions & 19 deletions
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‎Objects/listobject.c‎

Lines changed: 93 additions & 45 deletions
Original file line numberDiff line numberDiff line change
@@ -10,6 +10,7 @@
1010
#include "pycore_modsupport.h" // _PyArg_NoKwnames()
1111
#include "pycore_object.h" // _PyObject_GC_TRACK(), _PyDebugAllocatorStats()
1212
#include "pycore_tuple.h" // _PyTuple_FromArray()
13+
#include "pycore_setobject.h" // _PySet_NextEntry()
1314
#include <stddef.h>
1415

1516
/*[clinic input]
@@ -994,35 +995,36 @@ PyList_SetSlice(PyObject *a, Py_ssize_t ilow, Py_ssize_t ihigh, PyObject *v)
994995
return list_ass_slice((PyListObject *)a, ilow, ihigh, v);
995996
}
996997

997-
static PyObject *
998+
static int
998999
list_inplace_repeat_lock_held(PyListObject *self, Py_ssize_t n)
9991000
{
10001001
Py_ssize_t input_size = PyList_GET_SIZE(self);
10011002
if (input_size == 0 || n == 1) {
1002-
return Py_NewRef(self);
1003+
return 0;
10031004
}
10041005

10051006
if (n < 1) {
10061007
list_clear(self);
1007-
return Py_NewRef(self);
1008+
return 0;
10081009
}
10091010

10101011
if (input_size > PY_SSIZE_T_MAX / n) {
1011-
return PyErr_NoMemory();
1012+
PyErr_NoMemory();
1013+
return -1;
10121014
}
10131015
Py_ssize_t output_size = input_size * n;
10141016

1015-
if (list_resize(self, output_size) < 0)
1016-
return NULL;
1017+
if (list_resize(self, output_size) < 0) {
1018+
return -1;
1019+
}
10171020

10181021
PyObject **items = self->ob_item;
10191022
for (Py_ssize_t j = 0; j < input_size; j++) {
10201023
_Py_RefcntAdd(items[j], n-1);
10211024
}
10221025
_Py_memory_repeat((char *)items, sizeof(PyObject *)*output_size,
10231026
sizeof(PyObject *)*input_size);
1024-
1025-
return Py_NewRef(self);
1027+
return 0;
10261028
}
10271029

10281030
static PyObject *
@@ -1031,7 +1033,12 @@ list_inplace_repeat(PyObject *_self, Py_ssize_t n)
10311033
PyObject *ret;
10321034
PyListObject *self = (PyListObject *) _self;
10331035
Py_BEGIN_CRITICAL_SECTION(self);
1034-
ret = list_inplace_repeat_lock_held(self, n);
1036+
if (list_inplace_repeat_lock_held(self, n) < 0) {
1037+
ret = NULL;
1038+
}
1039+
else {
1040+
ret = Py_NewRef(self);
1041+
}
10351042
Py_END_CRITICAL_SECTION();
10361043
return ret;
10371044
}
@@ -1179,7 +1186,7 @@ list_extend_fast(PyListObject *self, PyObject *iterable)
11791186
}
11801187

11811188
static int
1182-
list_extend_iter(PyListObject *self, PyObject *iterable)
1189+
list_extend_iter_lock_held(PyListObject *self, PyObject *iterable)
11831190
{
11841191
PyObject *it = PyObject_GetIter(iterable);
11851192
if (it == NULL) {
@@ -1253,45 +1260,78 @@ list_extend_iter(PyListObject *self, PyObject *iterable)
12531260
return -1;
12541261
}
12551262

1256-
12571263
static int
1258-
list_extend(PyListObject *self, PyObject *iterable)
1264+
list_extend_lock_held(PyListObject *self, PyObject *iterable)
12591265
{
1260-
// Special cases:
1261-
// 1) lists and tuples which can use PySequence_Fast ops
1262-
// 2) extending self to self requires making a copy first
1263-
if (PyList_CheckExact(iterable)
1264-
|| PyTuple_CheckExact(iterable)
1265-
|| (PyObject *)self == iterable)
1266-
{
1267-
iterable = PySequence_Fast(iterable, "argument must be iterable");
1268-
if (!iterable) {
1269-
return -1;
1270-
}
1271-
1272-
int res = list_extend_fast(self, iterable);
1273-
Py_DECREF(iterable);
1274-
return res;
1275-
}
1276-
else {
1277-
return list_extend_iter(self, iterable);
1266+
PyObject *seq = PySequence_Fast(iterable, "argument must be iterable");
1267+
if (!seq) {
1268+
return -1;
12781269
}
1279-
}
12801270

1271+
int res = list_extend_fast(self, seq);
1272+
Py_DECREF(seq);
1273+
return res;
1274+
}
12811275

1282-
PyObject *
1283-
_PyList_Extend(PyListObject *self, PyObject *iterable)
1276+
static int
1277+
list_extend_set(PyListObject *self, PySetObject *other)
12841278
{
1285-
if (list_extend(self, iterable) < 0) {
1286-
return NULL;
1279+
Py_ssize_t m = Py_SIZE(self);
1280+
Py_ssize_t n = PySet_GET_SIZE(other);
1281+
if (list_resize(self, m + n) < 0) {
1282+
return -1;
12871283
}
1288-
Py_RETURN_NONE;
1284+
/* populate the end of self with iterable's items */
1285+
Py_ssize_t setpos = 0;
1286+
Py_hash_t hash;
1287+
PyObject *key;
1288+
PyObject **dest = self->ob_item + m;
1289+
while (_PySet_NextEntry((PyObject *)other, &setpos, &key, &hash)) {
1290+
Py_INCREF(key);
1291+
*dest = key;
1292+
dest++;
1293+
}
1294+
Py_SET_SIZE(self, m + n);
1295+
return 0;
12891296
}
12901297

1298+
static int
1299+
_list_extend(PyListObject *self, PyObject *iterable)
1300+
{
1301+
// Special case:
1302+
// lists and tuples which can use PySequence_Fast ops
1303+
// TODO(@corona10): Add more special cases for other types.
1304+
int res = -1;
1305+
if ((PyObject *)self == iterable) {
1306+
Py_BEGIN_CRITICAL_SECTION(self);
1307+
res = list_inplace_repeat_lock_held(self, 2);
1308+
Py_END_CRITICAL_SECTION();
1309+
}
1310+
else if (PyList_CheckExact(iterable)) {
1311+
Py_BEGIN_CRITICAL_SECTION2(self, iterable);
1312+
res = list_extend_lock_held(self, iterable);
1313+
Py_END_CRITICAL_SECTION2();
1314+
}
1315+
else if (PyTuple_CheckExact(iterable)) {
1316+
Py_BEGIN_CRITICAL_SECTION(self);
1317+
res = list_extend_lock_held(self, iterable);
1318+
Py_END_CRITICAL_SECTION();
1319+
}
1320+
else if (PyAnySet_CheckExact(iterable)) {
1321+
Py_BEGIN_CRITICAL_SECTION2(self, iterable);
1322+
res = list_extend_set(self, (PySetObject *)iterable);
1323+
Py_END_CRITICAL_SECTION2();
1324+
}
1325+
else {
1326+
Py_BEGIN_CRITICAL_SECTION(self);
1327+
res = list_extend_iter_lock_held(self, iterable);
1328+
Py_END_CRITICAL_SECTION();
1329+
}
1330+
return res;
1331+
}
12911332

12921333
/*[clinic input]
1293-
@critical_section self iterable
1294-
list.extend as py_list_extend
1334+
list.extend as list_extend
12951335
12961336
iterable: object
12971337
/
@@ -1300,12 +1340,20 @@ Extend list by appending elements from the iterable.
13001340
[clinic start generated code]*/
13011341

13021342
static PyObject *
1303-
py_list_extend_impl(PyListObject *self, PyObject *iterable)
1304-
/*[clinic end generated code: output=a2f115ceace2c845 input=1d42175414e1a5f3]*/
1343+
list_extend(PyListObject *self, PyObject *iterable)
1344+
/*[clinic end generated code: output=630fb3bca0c8e789 input=979da7597a515791]*/
13051345
{
1306-
return _PyList_Extend(self, iterable);
1346+
if (_list_extend(self, iterable) < 0) {
1347+
return NULL;
1348+
}
1349+
Py_RETURN_NONE;
13071350
}
13081351

1352+
PyObject *
1353+
_PyList_Extend(PyListObject *self, PyObject *iterable)
1354+
{
1355+
return list_extend(self, iterable);
1356+
}
13091357

13101358
int
13111359
PyList_Extend(PyObject *self, PyObject *iterable)
@@ -1314,7 +1362,7 @@ PyList_Extend(PyObject *self, PyObject *iterable)
13141362
PyErr_BadInternalCall();
13151363
return -1;
13161364
}
1317-
return list_extend((PyListObject*)self, iterable);
1365+
return _list_extend((PyListObject*)self, iterable);
13181366
}
13191367

13201368

@@ -1334,7 +1382,7 @@ static PyObject *
13341382
list_inplace_concat(PyObject *_self, PyObject *other)
13351383
{
13361384
PyListObject *self = (PyListObject *)_self;
1337-
if (list_extend(self, other) < 0) {
1385+
if (_list_extend(self, other) < 0) {
13381386
return NULL;
13391387
}
13401388
return Py_NewRef(self);
@@ -3168,7 +3216,7 @@ list___init___impl(PyListObject *self, PyObject *iterable)
31683216
list_clear(self);
31693217
}
31703218
if (iterable != NULL) {
3171-
if (list_extend(self, iterable) < 0) {
3219+
if (_list_extend(self, iterable) < 0) {
31723220
return -1;
31733221
}
31743222
}
@@ -3229,7 +3277,7 @@ static PyMethodDef list_methods[] = {
32293277
LIST_COPY_METHODDEF
32303278
LIST_APPEND_METHODDEF
32313279
LIST_INSERT_METHODDEF
3232-
PY_LIST_EXTEND_METHODDEF
3280+
LIST_EXTEND_METHODDEF
32333281
LIST_POP_METHODDEF
32343282
LIST_REMOVE_METHODDEF
32353283
LIST_INDEX_METHODDEF

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