Hi
Ok to backport this to gcc-10 branch ?
Tested under Linux x86_64.
François
On 13/04/21 10:51 pm, redi at gcc dot gnu.org wrote:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99402
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|[10/11 Regression] |[10 Regression] std::copy
|std::copy creates |creates _GLIBCXX_DEBUG
|_GLIBCXX_DEBUG false |false positive for attempt
|positive for attempt to |to subscript a
|subscript a dereferenceable |dereferenceable
|(start-of-sequence) |(start-of-sequence)
|iterator |iterator
--- Comment #10 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This was fixed on trunk by r11-8100:
libstdc++: [_GLIBCXX_DEBUG] Fix management of __dp_sign_max_size [PR 99402]
__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.
diff --git a/libstdc++-v3/include/debug/helper_functions.h b/libstdc++-v3/include/debug/helper_functions.h
index 62d5309257f..9e2d206f06c 100644
--- a/libstdc++-v3/include/debug/helper_functions.h
+++ b/libstdc++-v3/include/debug/helper_functions.h
@@ -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>
@@ -287,6 +287,18 @@ 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
diff --git a/libstdc++-v3/include/debug/macros.h b/libstdc++-v3/include/debug/macros.h
index 73fb50d0cbd..1f45f8e0adc 100644
--- a/libstdc++-v3/include/debug/macros.h
+++ b/libstdc++-v3/include/debug/macros.h
@@ -104,6 +104,12 @@ _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 \
{ \
@@ -115,7 +121,7 @@ _GLIBCXX_DEBUG_VERIFY(__gnu_debug::__can_advance(_First, _Size), \
._M_iterator(_Last1, #_Last1), \
__FILE__,__LINE__,__PRETTY_FUNCTION__); \
_GLIBCXX_DEBUG_VERIFY_COND_AT( \
- __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), \
@@ -133,7 +139,7 @@ _GLIBCXX_DEBUG_VERIFY(__gnu_debug::__can_advance(_First, _Size), \
._M_iterator(_Last1, #_Last1), \
__FILE__,__LINE__,__PRETTY_FUNCTION__); \
_GLIBCXX_DEBUG_VERIFY_COND_AT( \
- __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), \
diff --git a/libstdc++-v3/include/debug/safe_iterator.h b/libstdc++-v3/include/debug/safe_iterator.h
index 687b844fd75..2f51618dd88 100644
--- a/libstdc++-v3/include/debug/safe_iterator.h
+++ b/libstdc++-v3/include/debug/safe_iterator.h
@@ -405,6 +405,12 @@ 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,
@@ -956,6 +962,14 @@ 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,
diff --git a/libstdc++-v3/include/debug/safe_iterator.tcc b/libstdc++-v3/include/debug/safe_iterator.tcc
index 312a88911ee..79a8ee28d97 100644
--- a/libstdc++-v3/include/debug/safe_iterator.tcc
+++ b/libstdc++-v3/include/debug/safe_iterator.tcc
@@ -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.
@@ -224,9 +225,8 @@ 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
@@ -244,7 +244,7 @@ _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(),
@@ -261,7 +261,7 @@ _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))
@@ -283,7 +283,7 @@ _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)
{
@@ -311,7 +311,7 @@ _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>(
@@ -328,7 +328,7 @@ _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))
@@ -351,7 +351,7 @@ _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)
{
@@ -416,7 +416,7 @@ _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);
@@ -431,7 +431,7 @@ _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))
@@ -450,7 +450,7 @@ _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)
{
diff --git a/libstdc++-v3/include/debug/stl_iterator.h b/libstdc++-v3/include/debug/stl_iterator.h
index 6044f3588d9..02adb6e3c06 100644
--- a/libstdc++-v3/include/debug/stl_iterator.h
+++ b/libstdc++-v3/include/debug/stl_iterator.h
@@ -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)
diff --git a/libstdc++-v3/testsuite/25_algorithms/copy/debug/99402.cc b/libstdc++-v3/testsuite/25_algorithms/copy/debug/99402.cc
new file mode 100644
index 00000000000..041d222d079
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/copy/debug/99402.cc
@@ -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());
+}
