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libstdc++: [_GLIBCXX_DEBUG] Fix management of __dp_sign_max_size [PR 99402]

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__dp_sign precision indicates that we found out what iterator comes first or
last in the range. __dp_sign_max_size is the same plus it gives the information
of the max size of the range that is to say the max_size value such that
distance(lhs, rhs) < max_size.
Thanks to this additional information we are able to tell when a copy of n elements
to that range will fail even if we do not know exactly how large it is.

This patch makes sure that we are properly using this information.

libstdc++-v3/ChangeLog:

	PR libstdc++/99402
	* include/debug/helper_functions.h (__can_advance(_InputIterator,
	const std::pair<_Diff, _Distance_precision>&, int)): New.
	(__can_advance(const _Safe_iterator<>&,
	const std::pair<_Diff, _Distance_precision>&, int)): New.
	* include/debug/macros.h (__glibcxx_check_can_increment_dist): New,
	use latter.
	(__glibcxx_check_can_increment_range): Adapt to use latter.
	(__glibcxx_check_can_decrement_range): Likewise.
	* include/debug/safe_iterator.h
	(_Safe_iterator<>::_M_can_advance(const std::pair<_Diff, _Distance_precision>&,
	int)): New.
	(__can_advance(const _Safe_iterator<>&,
	const std::pair<_Diff, _Distance_precision>&, int)): New.
	* include/debug/safe_iterator.tcc
	(_Safe_iterator<>::_M_can_advance(const std::pair<_Diff, _Distance_precision>&,
	int)): New.
	(_Safe_iterator<>::_M_valid_range(const _Safe_iterator<>&,
	std::pair<difference_type, _Distance_precision>&, bool)): Adapt for
	__dp_sign_max_size.
	(__copy_move_a): Adapt to use __glibcxx_check_can_increment_dist.
	(__copy_move_backward_a): Likewise.
	(__equal_aux): Likewise.
	* include/debug/stl_iterator.h (__can_advance(const std::reverse_iterator<>&,
	const std::pair<_Diff, _Distance_precision>&, int)): New.
	(__can_advance(const std::move_iterator<>&,
	const std::pair<_Diff, _Distance_precision>&, int)): New.
	* testsuite/25_algorithms/copy/debug/99402.cc: New test.
This commit is contained in:
François Dumont 2021-03-07 19:11:02 +01:00
parent b04093adb2
commit cc79682046
6 changed files with 122 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
libstdc++-v3/include/debug/helper_functions.h
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@ -64,7 +64,7 @@ namespace __gnu_debug
{
private:
typedef
typename std::iterator_traits<_Iterator>::difference_type _ItDiffType;
typename std::iterator_traits<_Iterator>::difference_type _ItDiffType;
template<typename _DiffType,
typename = typename std::__is_void<_DiffType>::__type>
@ -291,6 +291,18 @@ namespace __gnu_debug
__can_advance(const _Safe_iterator<_Iterator, _Sequence, _Category>&,
_Size);
template<typename _InputIterator, typename _Diff>
_GLIBCXX_CONSTEXPR
inline bool
__can_advance(_InputIterator, const std::pair<_Diff, _Distance_precision>&, int)
{ return true; }
template<typename _Iterator, typename _Sequence, typename _Category,
typename _Diff>
bool
__can_advance(const _Safe_iterator<_Iterator, _Sequence, _Category>&,
const std::pair<_Diff, _Distance_precision>&, int);
/** Helper function to extract base iterator of random access safe iterator
* in order to reduce performance impact of debug mode. Limited to random
* access iterator because it is the only category for which it is possible

10
libstdc++-v3/include/debug/macros.h
View File

@ -94,6 +94,12 @@ _GLIBCXX_DEBUG_VERIFY(__gnu_debug::__can_advance(_First, _Size), \
._M_iterator(_First, #_First) \
._M_integer(_Size, #_Size))
#define __glibcxx_check_can_increment_dist(_First,_Dist,_Way) \
_GLIBCXX_DEBUG_VERIFY(__gnu_debug::__can_advance(_First, _Dist, _Way), \
_M_message(__gnu_debug::__msg_iter_subscript_oob) \
._M_iterator(_First, #_First) \
._M_integer(_Way * _Dist.first, #_Dist))
#define __glibcxx_check_can_increment_range(_First1,_Last1,_First2) \
do \
{ \
@ -105,7 +111,7 @@ _GLIBCXX_DEBUG_VERIFY(__gnu_debug::__can_advance(_First, _Size), \
._M_iterator(_Last1, #_Last1), \
__FILE__,__LINE__,__PRETTY_FUNCTION__); \
_GLIBCXX_DEBUG_VERIFY_AT_F( \
__gnu_debug::__can_advance(_First2, __dist.first),\
__gnu_debug::__can_advance(_First2, __dist, 1), \
_M_message(__gnu_debug::__msg_iter_subscript_oob)\
._M_iterator(_First2, #_First2) \
._M_integer(__dist.first), \
@ -123,7 +129,7 @@ _GLIBCXX_DEBUG_VERIFY(__gnu_debug::__can_advance(_First, _Size), \
._M_iterator(_Last1, #_Last1), \
__FILE__,__LINE__,__PRETTY_FUNCTION__); \
_GLIBCXX_DEBUG_VERIFY_AT_F( \
__gnu_debug::__can_advance(_First2, -__dist.first),\
__gnu_debug::__can_advance(_First2, __dist, -1), \
_M_message(__gnu_debug::__msg_iter_subscript_oob)\
._M_iterator(_First2, #_First2) \
._M_integer(-__dist.first), \

14
libstdc++-v3/include/debug/safe_iterator.h
View File

@ -407,6 +407,12 @@ namespace __gnu_debug
bool
_M_can_advance(difference_type __n, bool __strict = false) const;
// Can we advance the iterator using @p __dist in @p __way direction.
template<typename _Diff>
bool
_M_can_advance(const std::pair<_Diff, _Distance_precision>& __dist,
int __way) const;
// Is the iterator range [*this, __rhs) valid?
bool
_M_valid_range(const _Safe_iterator& __rhs,
@ -958,6 +964,14 @@ namespace __gnu_debug
_Size __n)
{ return __it._M_can_advance(__n); }
template<typename _Iterator, typename _Sequence, typename _Category,
typename _Diff>
inline bool
__can_advance(const _Safe_iterator<_Iterator, _Sequence, _Category>& __it,
const std::pair<_Diff, _Distance_precision>& __dist,
int __way)
{ return __it._M_can_advance(__dist, __way); }
template<typename _Iterator, typename _Sequence>
_Iterator
__base(const _Safe_iterator<_Iterator, _Sequence,

76
libstdc++-v3/include/debug/safe_iterator.tcc
View File

@ -92,24 +92,32 @@ namespace __gnu_debug
if (__n == 0)
return true;
std::pair<difference_type, _Distance_precision> __dist = __n < 0
? _M_get_distance_from_begin()
: _M_get_distance_to_end();
if (__n < 0)
{
std::pair<difference_type, _Distance_precision> __dist =
_M_get_distance_from_begin();
return __dist.second == __dp_exact
? __dist.first >= -__n
: !__strict && __dist.first > 0;
}
else
{
std::pair<difference_type, _Distance_precision> __dist =
_M_get_distance_to_end();
return __dist.second == __dp_exact
? __dist.first >= __n
: !__strict && __dist.first > 0;
}
__n = -__n;
return __dist.second > __dp_sign
? __dist.first >= __n
: !__strict && __dist.first > 0;
}
template<typename _Iterator, typename _Sequence, typename _Category>
template<typename _Diff>
bool
_Safe_iterator<_Iterator, _Sequence, _Category>::
_M_can_advance(const std::pair<_Diff, _Distance_precision>& __dist,
int __way) const
{
return __dist.second == __dp_exact
? _M_can_advance(__way * __dist.first)
: _M_can_advance(__way * (__dist.first == 0
? 0
: __dist.first < 0 ? -1 : 1));
}
template<typename _Iterator, typename _Sequence, typename _Category>
typename _Distance_traits<_Iterator>::__type
_Safe_iterator<_Iterator, _Sequence, _Category>::
@ -191,19 +199,12 @@ namespace __gnu_debug
/* Determine iterators order */
__dist = _M_get_distance_to(__rhs);
switch (__dist.second)
if (__dist.second != __dp_equality)
{
case __dp_equality:
if (__dist.first == 0)
return true;
break;
case __dp_sign:
case __dp_exact:
// If range is not empty first iterator must be dereferenceable.
if (__dist.first > 0)
return !__check_dereferenceable || _M_dereferenceable();
return __dist.first == 0;
return __dist.first == 0
|| (__dist.first > 0
&& (!__check_dereferenceable || _M_dereferenceable()));
}
// Assume that this is a valid range; we can't check anything else.
@ -225,9 +226,8 @@ namespace __gnu_debug
__dist = std::make_pair(__rhs.base() - this->base(), __dp_exact);
// If range is not empty first iterator must be dereferenceable.
if (__dist.first > 0)
return this->_M_dereferenceable();
return __dist.first == 0;
return __dist.first == 0
|| (__dist.first > 0 && this->_M_dereferenceable());
}
} // namespace __gnu_debug
@ -251,7 +251,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
typename ::__gnu_debug::_Distance_traits<_Ite>::__type __dist;
__glibcxx_check_valid_range2(__first, __last, __dist);
__glibcxx_check_can_increment(__result, __dist.first);
__glibcxx_check_can_increment_dist(__result, __dist, 1);
if (__dist.second > ::__gnu_debug::__dp_equality)
return std::__copy_move_a<_IsMove>(__first.base(), __last.base(),
@ -268,7 +268,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
typename ::__gnu_debug::_Distance_traits<_II>::__type __dist;
__glibcxx_check_valid_range2(__first, __last, __dist);
__glibcxx_check_can_increment(__result, __dist.first);
__glibcxx_check_can_increment_dist(__result, __dist, 1);
if (__dist.second > ::__gnu_debug::__dp_sign
&& __result._M_can_advance(__dist.first, true))
@ -290,7 +290,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
typename ::__gnu_debug::_Distance_traits<_IIte>::__type __dist;
__glibcxx_check_valid_range2(__first, __last, __dist);
__glibcxx_check_can_increment(__result, __dist.first);
__glibcxx_check_can_increment_dist(__result, __dist, 1);
if (__dist.second > ::__gnu_debug::__dp_equality)
{
@ -318,7 +318,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
typename ::__gnu_debug::_Distance_traits<_Ite>::__type __dist;
__glibcxx_check_valid_range2(__first, __last, __dist);
__glibcxx_check_can_increment(__result, -__dist.first);
__glibcxx_check_can_increment_dist(__result, __dist, -1);
if (__dist.second > ::__gnu_debug::__dp_equality)
return std::__copy_move_backward_a<_IsMove>(
@ -335,7 +335,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
typename ::__gnu_debug::_Distance_traits<_II>::__type __dist;
__glibcxx_check_valid_range2(__first, __last, __dist);
__glibcxx_check_can_increment(__result, -__dist.first);
__glibcxx_check_can_increment_dist(__result, __dist, -1);
if (__dist.second > ::__gnu_debug::__dp_sign
&& __result._M_can_advance(-__dist.first, true))
@ -358,7 +358,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
typename ::__gnu_debug::_Distance_traits<_IIte>::__type __dist;
__glibcxx_check_valid_range2(__first, __last, __dist);
__glibcxx_check_can_increment(__result, -__dist.first);
__glibcxx_check_can_increment_dist(__result, __dist, -1);
if (__dist.second > ::__gnu_debug::__dp_equality)
{
@ -423,7 +423,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
typename ::__gnu_debug::_Distance_traits<_II1>::__type __dist;
__glibcxx_check_valid_range2(__first1, __last1, __dist);
__glibcxx_check_can_increment(__first2, __dist.first);
__glibcxx_check_can_increment_dist(__first2, __dist, 1);
if (__dist.second > ::__gnu_debug::__dp_equality)
return std::__equal_aux(__first1.base(), __last1.base(), __first2);
@ -438,7 +438,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
typename ::__gnu_debug::_Distance_traits<_II1>::__type __dist;
__glibcxx_check_valid_range2(__first1, __last1, __dist);
__glibcxx_check_can_increment(__first2, __dist.first);
__glibcxx_check_can_increment_dist(__first2, __dist, 1);
if (__dist.second > ::__gnu_debug::__dp_sign
&& __first2._M_can_advance(__dist.first, true))
@ -457,7 +457,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
typename ::__gnu_debug::_Distance_traits<_II1>::__type __dist;
__glibcxx_check_valid_range2(__first1, __last1, __dist);
__glibcxx_check_can_increment(__first2, __dist.first);
__glibcxx_check_can_increment_dist(__first2, __dist, 1);
if (__dist.second > ::__gnu_debug::__dp_equality)
{

14
libstdc++-v3/include/debug/stl_iterator.h
View File

@ -52,6 +52,13 @@ namespace __gnu_debug
__can_advance(const std::reverse_iterator<_Iterator>& __it, _Size __n)
{ return __can_advance(__it.base(), -__n); }
template<typename _Iterator, typename _Diff>
inline bool
__can_advance(const std::reverse_iterator<_Iterator>& __it,
const std::pair<_Diff, _Distance_precision>& __dist,
int __way)
{ return __can_advance(__it.base(), __dist, -__way); }
template<typename _Iterator, typename _Sequence>
inline std::reverse_iterator<_Iterator>
__base(const std::reverse_iterator<_Safe_iterator<
@ -101,6 +108,13 @@ namespace __gnu_debug
__can_advance(const std::move_iterator<_Iterator>& __it, _Size __n)
{ return __can_advance(__it.base(), __n); }
template<typename _Iterator, typename _Diff>
inline bool
__can_advance(const std::move_iterator<_Iterator>& __it,
const std::pair<_Diff, _Distance_precision>& __dist,
int __way)
{ return __can_advance(__it.base(), __dist, __way); }
template<typename _Iterator>
inline auto
__unsafe(const std::move_iterator<_Iterator>& __it)

35
libstdc++-v3/testsuite/25_algorithms/copy/debug/99402.cc Normal file
View File

@ -0,0 +1,35 @@
// Copyright (C) 2021 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// { dg-options "-D_GLIBCXX_DEBUG" }
// { dg-do run }
#include <algorithm>
#include <set>
#include <vector>
// PR libstdc++/99402
using namespace std;
int main()
{
// any container with non-random access iterators:
const set<int> source = { 0, 1 };
vector<int> dest(1);
copy(source.begin(), ++source.begin(), dest.begin());
}