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gh-120176: Reduce number of compares in index range checks #120181

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13 changes: 13 additions & 0 deletions Include/internal/pycore_abstract.h
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Expand Up@@ -21,6 +21,19 @@ PyObject *_PyNumber_InPlacePowerNoMod(PyObject *lhs, PyObject *rhs);

extern int _PyObject_HasLen(PyObject *o);

static inline int
_Py_ValidIndex(Py_ssize_t i, Py_ssize_t limit)
{
/* The cast to size_t lets us use just a single comparison
to check whether i is in the range: 0 <= i < limit.

See: Section 14.2 "Bounds Checking" in the Agner Fog
optimization manual found at:
https://www.agner.org/optimize/optimizing_cpp.pdf
*/
return (size_t) i < (size_t) limit;
}

/* === Sequence protocol ================================================ */

#define PY_ITERSEARCH_COUNT 1
Expand Down
5 changes: 3 additions & 2 deletions Modules/_ctypes/_ctypes.c
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Expand Up@@ -106,6 +106,7 @@ bytes(cdata)
# include <windows.h>
#endif

#include "pycore_abstract.h" // _Py_ValidIndex()
#include "pycore_call.h" // _PyObject_CallNoArgs()
#include "pycore_ceval.h" // _Py_EnterRecursiveCall()
#ifdef MS_WIN32
Expand DownExpand Up@@ -4645,7 +4646,7 @@ Array_item(PyObject *myself, Py_ssize_t index)
CDataObject *self = (CDataObject *)myself;
Py_ssize_t offset, size;

if (index < 0 || index >= self->b_length) {
if (!_Py_ValidIndex(index, self->b_length)) {
PyErr_SetString(PyExc_IndexError,
"invalid index");
return NULL;
Expand DownExpand Up@@ -4800,7 +4801,7 @@ Array_ass_item(PyObject *myself, Py_ssize_t index, PyObject *value)
}
assert(stginfo); /* Cannot be NULL for array object instances */

if (index < 0 || index >= stginfo->length) {
if (!_Py_ValidIndex(index, stginfo->length)) {
PyErr_SetString(PyExc_IndexError,
"invalid index");
return -1;
Expand Down
5 changes: 3 additions & 2 deletions Modules/_elementtree.c
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Expand Up@@ -16,6 +16,7 @@
#endif

#include "Python.h"
#include "pycore_abstract.h" // _Py_ValidIndex()
#include "pycore_import.h" // _PyImport_GetModuleAttrString()
#include "pycore_pyhash.h" // _Py_HashSecret

Expand DownExpand Up@@ -1486,7 +1487,7 @@ element_getitem(PyObject* self_, Py_ssize_t index)
{
ElementObject* self = (ElementObject*) self_;

if (!self->extra || index < 0 || index >= self->extra->length) {
if (!self->extra || !_Py_ValidIndex(index, self->extra->length)) {
PyErr_SetString(
PyExc_IndexError,
"child index out of range"
Expand DownExpand Up@@ -1738,7 +1739,7 @@ element_setitem(PyObject* self_, Py_ssize_t index, PyObject* item)
Py_ssize_t i;
PyObject* old;

if (!self->extra || index < 0 || index >= self->extra->length) {
if (!self->extra || !_Py_ValidIndex(index, self->extra->length)) {
PyErr_SetString(
PyExc_IndexError,
"child assignment index out of range");
Expand Down
3 changes: 2 additions & 1 deletion Modules/_sre/sre.c
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Expand Up@@ -39,6 +39,7 @@ static const char copyright[] =
" SRE 2.2.2 Copyright (c) 1997-2002 by Secret Labs AB ";

#include "Python.h"
#include "pycore_abstract.h" // _Py_ValidIndex()
#include "pycore_critical_section.h" // Py_BEGIN_CRITICAL_SECTION
#include "pycore_dict.h" // _PyDict_Next()
#include "pycore_long.h" // _PyLong_GetZero()
Expand DownExpand Up@@ -2208,7 +2209,7 @@ match_getindex(MatchObject* self, PyObject* index)
}
}
}
if (i < 0 || i >= self->groups) {
if (!_Py_ValidIndex(i, self->groups)) {
/* raise IndexError if we were given a bad group number */
if (!PyErr_Occurred()) {
PyErr_SetString(PyExc_IndexError, "no such group");
Expand Down
9 changes: 5 additions & 4 deletions Modules/arraymodule.c
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Expand Up@@ -8,6 +8,7 @@
#endif

#include "Python.h"
#include "pycore_abstract.h" // _Py_ValidIndex()
#include "pycore_bytesobject.h" // _PyBytes_Repeat
#include "pycore_call.h" // _PyObject_CallMethod()
#include "pycore_ceval.h" // _PyEval_GetBuiltin()
Expand DownExpand Up@@ -851,7 +852,7 @@ array_length(arrayobject *a)
static PyObject *
array_item(arrayobject *a, Py_ssize_t i)
{
if (i < 0 || i >= Py_SIZE(a)) {
if (!_Py_ValidIndex(i, Py_SIZE(a))) {
PyErr_SetString(PyExc_IndexError, "array index out of range");
return NULL;
}
Expand DownExpand Up@@ -1028,7 +1029,7 @@ array_del_slice(arrayobject *a, Py_ssize_t ilow, Py_ssize_t ihigh)
static int
array_ass_item(arrayobject *a, Py_ssize_t i, PyObject *v)
{
if (i < 0 || i >= Py_SIZE(a)) {
if (!_Py_ValidIndex(i, Py_SIZE(a))) {
PyErr_SetString(PyExc_IndexError,
"array assignment index out of range");
return -1;
Expand DownExpand Up@@ -1311,7 +1312,7 @@ array_array_pop_impl(arrayobject *self, Py_ssize_t i)
}
if (i < 0)
i += Py_SIZE(self);
if (i < 0 || i >= Py_SIZE(self)) {
if (!_Py_ValidIndex(i, Py_SIZE(self))) {
PyErr_SetString(PyExc_IndexError, "pop index out of range");
return NULL;
}
Expand DownExpand Up@@ -2502,7 +2503,7 @@ array_ass_subscr(arrayobject* self, PyObject* item, PyObject* value)
return -1;
if (i < 0)
i += Py_SIZE(self);
if (i < 0 || i >= Py_SIZE(self)) {
if (!_Py_ValidIndex(i, Py_SIZE(self))) {
PyErr_SetString(PyExc_IndexError,
"array assignment index out of range");
return -1;
Expand Down
12 changes: 6 additions & 6 deletions Modules/mmapmodule.c
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Original file line numberDiff line numberDiff line change
Expand Up@@ -23,7 +23,7 @@
#endif

#include <Python.h>
#include "pycore_abstract.h" // _Py_convert_optional_to_ssize_t()
#include "pycore_abstract.h" // _Py_convert_optional_to_ssize_t(), _Py_ValidIndex()
#include "pycore_bytesobject.h" // _PyBytes_Find()
#include "pycore_fileutils.h" // _Py_stat_struct

Expand DownExpand Up@@ -1131,7 +1131,7 @@ mmap_madvise_method(mmap_object *self, PyObject *args)
return NULL;
}

if (start < 0 || start >= self->size) {
if (!_Py_ValidIndex(start, self->size)) {
PyErr_SetString(PyExc_ValueError, "madvise start out of bounds");
return NULL;
}
Expand DownExpand Up@@ -1229,7 +1229,7 @@ static PyObject *
mmap_item(mmap_object *self, Py_ssize_t i)
{
CHECK_VALID(NULL);
if (i < 0 || i >= self->size) {
if (!_Py_ValidIndex(i, self->size)) {
PyErr_SetString(PyExc_IndexError, "mmap index out of range");
return NULL;
}
Expand All@@ -1251,7 +1251,7 @@ mmap_subscript(mmap_object *self, PyObject *item)
return NULL;
if (i < 0)
i += self->size;
if (i < 0 || i >= self->size) {
if (!_Py_ValidIndex(i, self->size)) {
PyErr_SetString(PyExc_IndexError,
"mmap index out of range");
return NULL;
Expand DownExpand Up@@ -1309,7 +1309,7 @@ mmap_ass_item(mmap_object *self, Py_ssize_t i, PyObject *v)
const char *buf;

CHECK_VALID(-1);
if (i < 0 || i >= self->size) {
if (!_Py_ValidIndex(i, self->size)) {
PyErr_SetString(PyExc_IndexError, "mmap index out of range");
return -1;
}
Expand DownExpand Up@@ -1349,7 +1349,7 @@ mmap_ass_subscript(mmap_object *self, PyObject *item, PyObject *value)
return -1;
if (i < 0)
i += self->size;
if (i < 0 || i >= self->size) {
if (!_Py_ValidIndex(i, self->size)) {
PyErr_SetString(PyExc_IndexError,
"mmap index out of range");
return -1;
Expand Down
12 changes: 6 additions & 6 deletions Objects/bytearrayobject.c
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@@ -1,7 +1,7 @@
/* PyByteArray (bytearray) implementation */

#include "Python.h"
#include "pycore_abstract.h" // _PyIndex_Check()
#include "pycore_abstract.h" // _PyIndex_Check(), _Py_ValidIndex()
#include "pycore_bytes_methods.h"
#include "pycore_bytesobject.h"
#include "pycore_ceval.h" // _PyEval_GetBuiltin()
Expand DownExpand Up@@ -359,7 +359,7 @@ bytearray_irepeat(PyByteArrayObject *self, Py_ssize_t count)
static PyObject *
bytearray_getitem(PyByteArrayObject *self, Py_ssize_t i)
{
if (i < 0 || i >= Py_SIZE(self)) {
if (!_Py_ValidIndex(i, Py_SIZE(self))) {
PyErr_SetString(PyExc_IndexError, "bytearray index out of range");
return NULL;
}
Expand All@@ -378,7 +378,7 @@ bytearray_subscript(PyByteArrayObject *self, PyObject *index)
if (i < 0)
i += PyByteArray_GET_SIZE(self);

if (i < 0 || i >= Py_SIZE(self)) {
if (!_Py_ValidIndex(i, Py_SIZE(self))) {
PyErr_SetString(PyExc_IndexError, "bytearray index out of range");
return NULL;
}
Expand DownExpand Up@@ -573,7 +573,7 @@ bytearray_setitem(PyByteArrayObject *self, Py_ssize_t i, PyObject *value)
i += Py_SIZE(self);
}

if (i < 0 || i >= Py_SIZE(self)) {
if (!_Py_ValidIndex(i, Py_SIZE(self))) {
PyErr_SetString(PyExc_IndexError, "bytearray index out of range");
return -1;
}
Expand DownExpand Up@@ -613,7 +613,7 @@ bytearray_ass_subscript(PyByteArrayObject *self, PyObject *index, PyObject *valu
i += PyByteArray_GET_SIZE(self);
}

if (i < 0 || i >= Py_SIZE(self)) {
if (!_Py_ValidIndex(i, Py_SIZE(self))) {
PyErr_SetString(PyExc_IndexError, "bytearray index out of range");
return -1;
}
Expand DownExpand Up@@ -1911,7 +1911,7 @@ bytearray_pop_impl(PyByteArrayObject *self, Py_ssize_t index)
}
if (index < 0)
index += Py_SIZE(self);
if (index < 0 || index >= Py_SIZE(self)) {
if (!_Py_ValidIndex(index, Py_SIZE(self))) {
PyErr_SetString(PyExc_IndexError, "pop index out of range");
return NULL;
}
Expand Down
4 changes: 2 additions & 2 deletions Objects/bytes_methods.c
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@@ -1,5 +1,5 @@
#include "Python.h"
#include "pycore_abstract.h" // _PyIndex_Check()
#include "pycore_abstract.h" // _PyIndex_Check(), _Py_ValidIndex()
#include "pycore_bytes_methods.h"

PyDoc_STRVAR_shared(_Py_isspace__doc__,
Expand DownExpand Up@@ -660,7 +660,7 @@ _Py_bytes_contains(const char *str, Py_ssize_t len, PyObject *arg)
PyBuffer_Release(&varg);
return pos >= 0;
}
if (ival < 0 || ival >= 256) {
if (!_Py_ValidIndex(ival, 256)) {
PyErr_SetString(PyExc_ValueError, "byte must be in range(0, 256)");
return -1;
}
Expand Down
13 changes: 6 additions & 7 deletions Objects/bytesobject.c
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@@ -1,7 +1,7 @@
/* bytes object implementation */

#include "Python.h"
#include "pycore_abstract.h" // _PyIndex_Check()
#include "pycore_abstract.h" // _PyIndex_Check(), _Py_ValidIndex()
#include "pycore_bytes_methods.h" // _Py_bytes_startswith()
#include "pycore_bytesobject.h" // _PyBytes_Find(), _PyBytes_Repeat()
#include "pycore_call.h" // _PyObject_CallNoArgs()
Expand DownExpand Up@@ -1506,7 +1506,7 @@ bytes_contains(PyObject *self, PyObject *arg)
static PyObject *
bytes_item(PyBytesObject *a, Py_ssize_t i)
{
if (i < 0 || i >= Py_SIZE(a)) {
if (!_Py_ValidIndex(i, Py_SIZE(a))) {
PyErr_SetString(PyExc_IndexError, "index out of range");
return NULL;
}
Expand DownExpand Up@@ -1613,7 +1613,7 @@ bytes_subscript(PyBytesObject* self, PyObject* item)
return NULL;
if (i < 0)
i += PyBytes_GET_SIZE(self);
if (i < 0 || i >= PyBytes_GET_SIZE(self)) {
if (!_Py_ValidIndex(i, PyBytes_GET_SIZE(self))) {
PyErr_SetString(PyExc_IndexError,
"index out of range");
return NULL;
Expand DownExpand Up@@ -2810,7 +2810,7 @@ _PyBytes_FromList(PyObject *x)
if (value == -1 && PyErr_Occurred())
goto error;

if (value < 0 || value >= 256) {
if (!_Py_ValidIndex(value, 256)) {
PyErr_SetString(PyExc_ValueError,
"bytes must be in range(0, 256)");
goto error;
Expand DownExpand Up@@ -2851,7 +2851,7 @@ _PyBytes_FromTuple(PyObject *x)
if (value == -1 && PyErr_Occurred())
goto error;

if (value < 0 || value >= 256) {
if (!_Py_ValidIndex(value, 256)) {
PyErr_SetString(PyExc_ValueError,
"bytes must be in range(0, 256)");
goto error;
Expand DownExpand Up@@ -2904,7 +2904,7 @@ _PyBytes_FromIterator(PyObject *it, PyObject *x)
goto error;

/* Range check */
if (value < 0 || value >= 256) {
if (!_Py_ValidIndex(value, 256)) {
PyErr_SetString(PyExc_ValueError,
"bytes must be in range(0, 256)");
goto error;
Expand DownExpand Up@@ -3662,4 +3662,3 @@ _PyBytes_Repeat(char* dest, Py_ssize_t len_dest,
}
}
}

5 changes: 3 additions & 2 deletions Objects/dictobject.c
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Expand Up@@ -116,6 +116,7 @@ As a consequence of this, split keys have a maximum size of 16.
#define PyDict_MINSIZE 8

#include "Python.h"
#include "pycore_abstract.h" // _Py_ValidIndex()
#include "pycore_bitutils.h" // _Py_bit_length
#include "pycore_call.h" // _PyObject_CallNoArgs()
#include "pycore_ceval.h" // _PyEval_GetBuiltin()
Expand DownExpand Up@@ -2814,7 +2815,7 @@ _PyDict_Next(PyObject *op, Py_ssize_t *ppos, PyObject **pkey,
i = *ppos;
if (_PyDict_HasSplitTable(mp)) {
assert(mp->ma_used <= SHARED_KEYS_MAX_SIZE);
if (i < 0 || i >= mp->ma_used)
if (!_Py_ValidIndex(i, mp->ma_used))
return 0;
int index = get_index_from_order(mp, i);
value = mp->ma_values->values[index];
Expand All@@ -2824,7 +2825,7 @@ _PyDict_Next(PyObject *op, Py_ssize_t *ppos, PyObject **pkey,
}
else {
Py_ssize_t n = mp->ma_keys->dk_nentries;
if (i < 0 || i >= n)
if (!_Py_ValidIndex(i, n))
return 0;
if (DK_IS_UNICODE(mp->ma_keys)) {
PyDictUnicodeEntry *entry_ptr = &DK_UNICODE_ENTRIES(mp->ma_keys)[i];
Expand Down
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