Attachment 26323 Details for Bug 51823 – implement DR 198

[patch] implement DR 198

51823.txt (text/plain), 12.85 KB, created by Jonathan Wakely on 2012-01-14 15:43:52 UTC

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Creator: Jonathan Wakely

Created: 2012-01-14 15:43:52 UTC

Size: 12.85 KB

patch

obsolete

>diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
>index fa87445..bbdad00 100644
>--- a/libstdc++-v3/ChangeLog
>+++ b/libstdc++-v3/ChangeLog
>@@ -1,3 +1,11 @@
>+2012-01-14  Jonathan Wakely  <jwakely.gcc@gmail.com>
>+
>+	PR libstdc++/51823
>+	* include/bits/stl_iterator.h (reverse_iterator): Implement DR 198,
>+	disabling the auxiliary member for the library's own iterator types.
>+	* testsuite/24_iterators/reverse_iterator/51823.cc: New.
>+	* testsuite/24_iterators/reverse_iterator/51823-2.cc: New.
>+
> 2012-01-13  FranÃ§ois Dumont  <fdumont@gcc.gnu.org>
> 
> 	* include/bits/hashtable_policy.h (_Hash_node_base): New, use it as
>diff --git a/libstdc++-v3/include/bits/stl_iterator.h b/libstdc++-v3/include/bits/stl_iterator.h
>index 624ae64..eae1ce2 100644
>--- a/libstdc++-v3/include/bits/stl_iterator.h
>+++ b/libstdc++-v3/include/bits/stl_iterator.h
>@@ -75,6 +75,49 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>    * @{
>    */
> 
>+  template<typename _Iterator>
>+    struct __cache_rev_iter_deref
>+    {
>+      static const bool __value = true;
>+    };
>+  template<typename _Iterator>
>+    const bool __cache_rev_iter_deref<_Iterator>::__value;
>+
>+  template<typename _Tp>
>+    struct __cache_rev_iter_deref<_Tp*>
>+    {
>+      static const bool __value = false;
>+    };
>+  template<typename _Tp>
>+    const bool __cache_rev_iter_deref<_Tp*>::__value;
>+
>+  template<typename _Iterator,
>+           bool = __cache_rev_iter_deref<_Iterator>::__value>
>+    class __reverse_iter_deref_cache
>+    {
>+      mutable _Iterator _M_deref_tmp;
>+
>+    protected:
>+      typename iterator_traits<_Iterator>::reference
>+      _M_deref(_Iterator __it) const
>+      {
>+        _M_deref_tmp = __it;
>+        return *--_M_deref_tmp;
>+      }
>+    };
>+
>+  template<typename _Iterator>
>+    class __reverse_iter_deref_cache<_Iterator, false>
>+    {
>+    protected:
>+      typename iterator_traits<_Iterator>::reference
>+      _M_deref(_Iterator __it) const
>+      {
>+        _Iterator __deref_tmp = __it;
>+        return *--__deref_tmp;
>+      }
>+    };
>+
>   // 24.4.1 Reverse iterators
>   /**
>    *  Bidirectional and random access iterators have corresponding reverse
>@@ -100,7 +143,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> 		      typename iterator_traits<_Iterator>::value_type,
> 		      typename iterator_traits<_Iterator>::difference_type,
> 		      typename iterator_traits<_Iterator>::pointer,
>-                      typename iterator_traits<_Iterator>::reference>
>+                      typename iterator_traits<_Iterator>::reference>,
>+      private __reverse_iter_deref_cache<_Iterator>
>     {
>     protected:
>       _Iterator current;
>@@ -148,6 +192,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>       base() const
>       { return current; }
> 
>+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
>+      // DR 198 Avoid returning a reference that persists beyond the
>+      // lifetime of its associated iterator.
>       /**
>        *  @return  TODO
>        *
>@@ -155,10 +202,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>       */
>       reference
>       operator*() const
>-      {
>-	_Iterator __tmp = current;
>-	return *--__tmp;
>-      }
>+      { return this->_M_deref(current); }
> 
>       /**
>        *  @return  TODO
>@@ -901,7 +945,101 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
> _GLIBCXX_END_NAMESPACE_VERSION
> } // namespace
> 
>+namespace std _GLIBCXX_VISIBILITY(default)
>+{
>+_GLIBCXX_BEGIN_NAMESPACE_VERSION
>+  // __normal_iterator does not need to cache the result of dereferencing
>+  template<typename _Iter, typename _Cont>
>+    struct __cache_rev_iter_deref<__gnu_cxx::__normal_iterator<_Iter, _Cont> >
>+    : __cache_rev_iter_deref<_Iter>
>+    { };
>+
>+  // deque iterator
>+  template<typename _Tp, typename _Ref, typename _Ptr> struct _Deque_iterator;
>+
>+  template<typename _Tp, typename _Ref, typename _Ptr>
>+    struct __cache_rev_iter_deref<_Deque_iterator<_Tp, _Ref, _Ptr> >
>+    { static const bool __value = false; };
>+
>+  template<typename _Tp, typename _Ref, typename _Ptr>
>+    const bool
>+    __cache_rev_iter_deref<_Deque_iterator<_Tp, _Ref, _Ptr> >::__value;
>+
>+  // list iterators
>+  template<typename _Tp> struct _List_iterator;
>+
>+  template<typename _Tp>
>+    struct __cache_rev_iter_deref<_List_iterator<_Tp> >
>+    { static const bool __value = false; };
>+
>+  template<typename _Tp>
>+    const bool __cache_rev_iter_deref<_List_iterator<_Tp> >::__value;
>+
>+  template<typename _Tp> struct _List_const_iterator;
>+
>+  template<typename _Tp>
>+    struct __cache_rev_iter_deref<_List_const_iterator<_Tp> >
>+    { static const bool __value = false; };
>+
>+  template<typename _Tp>
>+    const bool __cache_rev_iter_deref<_List_const_iterator<_Tp> >::__value;
>+
>+  // associative container iterators
>+  template<typename _Tp> struct _Rb_tree_iterator;
>+
>+  template<typename _Tp>
>+    struct __cache_rev_iter_deref<_Rb_tree_iterator<_Tp> >
>+    { static const bool __value = false; };
>+
>+  template<typename _Tp>
>+    const bool __cache_rev_iter_deref<_Rb_tree_iterator<_Tp> >::__value;
>+
>+  template<typename _Tp> struct _Rb_tree_const_iterator;
>+
>+  template<typename _Tp>
>+    struct __cache_rev_iter_deref<_Rb_tree_const_iterator<_Tp> >
>+    { static const bool __value = false; };
>+
>+  template<typename _Tp>
>+    const bool __cache_rev_iter_deref<_Rb_tree_const_iterator<_Tp> >::__value;
>+
>+_GLIBCXX_END_NAMESPACE_VERSION
>+} // namespace
>+
> #ifdef __GXX_EXPERIMENTAL_CXX0X__
>+namespace std _GLIBCXX_VISIBILITY(default)
>+{
>+namespace __detail
>+{
>+_GLIBCXX_BEGIN_NAMESPACE_VERSION
>+  // unordered container iterators
>+  template<typename, bool, bool> struct _Node_iterator;
>+  template<typename, bool, bool> struct _Node_const_iterator;
>+_GLIBCXX_END_NAMESPACE_VERSION
>+} // namespace __detail
>+
>+_GLIBCXX_BEGIN_NAMESPACE_VERSION
>+  template<typename _Value, bool _B1, bool _B2>
>+    struct __cache_rev_iter_deref<__detail::_Node_iterator<_Value, _B1, _B2>>
>+    { static const bool __value = false; };
>+
>+  template<typename _Value, bool _B1, bool _B2>
>+    const bool
>+    __cache_rev_iter_deref<__detail::_Node_iterator<_Value,
>+                                                    _B1, _B2>>::__value;
>+
>+
>+  template<typename _Value, bool _B1, bool _B2>
>+    struct __cache_rev_iter_deref<__detail::_Node_const_iterator<_Value,
>+                                                                 _B1, _B2>>
>+    { static const bool __value = false; };
>+
>+  template<typename _Value, bool _B1, bool _B2>
>+    const bool
>+    __cache_rev_iter_deref<__detail::_Node_const_iterator<_Value,
>+                                                          _B1, _B2>>::__value;
>+_GLIBCXX_END_NAMESPACE_VERSION
>+} // namespace std
> 
> namespace std _GLIBCXX_VISIBILITY(default)
> {
>@@ -1127,6 +1265,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>     __make_move_if_noexcept_iterator(_Iterator __i)
>     { return _ReturnType(__i); }
> 
>+  template<typename _Iterator>
>+    struct __cache_rev_iter_deref<move_iterator<_Iterator>>
>+    : __cache_rev_iter_deref<_Iterator>
>+    { };
>+
>   // @} group iterators
> 
> _GLIBCXX_END_NAMESPACE_VERSION
>diff --git a/libstdc++-v3/testsuite/24_iterators/reverse_iterator/51823-2.cc b/libstdc++-v3/testsuite/24_iterators/reverse_iterator/51823-2.cc
>new file mode 100644
>index 0000000..7d5efe2
>--- /dev/null
>+++ b/libstdc++-v3/testsuite/24_iterators/reverse_iterator/51823-2.cc
>@@ -0,0 +1,77 @@
>+// Copyright (C) 2012 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/>.
>+
>+// 24.5.1 Reverse iterators
>+
>+// DR 198.
>+// Validity of pointers and references unspecified after iterator destruction.
>+
>+// libstdc++/51823
>+
>+// { do-do compile }
>+// { do-options "-std=gnu++11" }
>+
>+#include <iterator>
>+#include <array>
>+#include <deque>
>+#include <list>
>+#include <vector>
>+#include <map>
>+#include <set>
>+#include <unordered_map>
>+#include <unordered_set>
>+
>+template<typename T>
>+constexpr bool test()
>+{
>+  return sizeof(T) == sizeof(std::reverse_iterator<T>);
>+}
>+
>+static_assert( test<int*>(), "pointer" );
>+static_assert( test<const int*>(), "pointer const" );
>+
>+static_assert( test<std::string::iterator>(), "string" );
>+static_assert( test<std::string::const_iterator>(), "string const" );
>+
>+static_assert( test<std::array<int, 2>::iterator>(), "array" );
>+static_assert( test<std::array<int, 2>::const_iterator>(), "array const" );
>+
>+static_assert( test<std::list<int>::iterator>(), "list" );
>+static_assert( test<std::list<int>::const_iterator>(), "list const" );
>+
>+static_assert( test<std::deque<int>::iterator>(), "deque" );
>+static_assert( test<std::deque<int>::const_iterator>(), "deque const" );
>+
>+static_assert( test<std::vector<int>::iterator>(), "vector" );
>+static_assert( test<std::vector<int>::const_iterator>(), "vector const" );
>+
>+static_assert( test<std::map<int,int>::iterator>(), "map" );
>+static_assert( test<std::map<int,int>::const_iterator>(), "map const" );
>+
>+static_assert( test<std::set<int>::iterator>(), "set" );
>+static_assert( test<std::set<int>::const_iterator>(), "set const" );
>+
>+static_assert( test<std::unordered_map<int,int>::iterator>(),
>+               "unordered_map" );
>+static_assert( test<std::unordered_map<int,int>::const_iterator>(),
>+               "unordered_map const" );
>+
>+static_assert( test<std::unordered_set<int>::iterator>(),
>+               "unordered_set" );
>+static_assert( test<std::unordered_set<int>::const_iterator>(),
>+               "unordered_set const" );
>+
>diff --git a/libstdc++-v3/testsuite/24_iterators/reverse_iterator/51823.cc b/libstdc++-v3/testsuite/24_iterators/reverse_iterator/51823.cc
>new file mode 100644
>index 0000000..a8c733f
>--- /dev/null
>+++ b/libstdc++-v3/testsuite/24_iterators/reverse_iterator/51823.cc
>@@ -0,0 +1,108 @@
>+// Copyright (C) 2012 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/>.
>+
>+// 24.5.1 Reverse iterators
>+
>+// DR 198.
>+// Validity of pointers and references unspecified after iterator destruction.
>+
>+// libstdc++/51823
>+
>+#include <iterator>
>+#include <vector>
>+#include <testsuite_hooks.h>
>+
>+struct datum
>+{
>+  unsigned use_count;
>+};
>+
>+std::vector<datum> data(6);
>+unsigned iterator_id = 0;
>+
>+struct iterator
>+{
>+  typedef datum                           value_type;
>+  typedef datum&                          reference;
>+  typedef datum*                          pointer;
>+  typedef std::ptrdiff_t                  difference_type;
>+  typedef std::bidirectional_iterator_tag iterator_category;
>+
>+  iterator() : id(-1) { }
>+  iterator(unsigned id) : id(id) { data[id].use_count++; }
>+  iterator(const iterator& i) : id(i.id) { data[id].use_count++; }
>+
>+  ~iterator() { if (id < data.size()) data[id].use_count--; }
>+
>+  iterator& operator=(iterator i) { swap(i); }
>+
>+  reference operator*() const { return data[id]; }
>+  pointer   operator->() const { return &data[id]; }
>+
>+  iterator& operator++()
>+  {
>+    data[id].use_count--;
>+    ++id;
>+    data[id].use_count++;
>+    return *this;
>+  }
>+
>+  iterator& operator--()
>+  {
>+    data[id].use_count--;
>+    --id;
>+    data[id].use_count++;
>+    return *this;
>+  }
>+
>+  iterator operator++(int) { iterator tmp = *this; ++*this; return tmp; }
>+  iterator operator--(int) { iterator tmp = *this; --*this; return tmp; }
>+
>+private:
>+  void swap(iterator& i) { std::swap(id, i.id); }
>+
>+  unsigned id;
>+};
>+
>+void test01()
>+{
>+  bool test __attribute__((unused)) = true;
>+
>+  typedef std::reverse_iterator<iterator> reverse_iterator;
>+
>+  iterator it1(2);
>+  reverse_iterator rit1(it1);
>+  VERIFY( (*rit1).use_count != 0 );
>+  VERIFY( rit1->use_count != 0 );
>+  ++rit1;
>+  VERIFY( (*rit1).use_count != 0 );
>+  VERIFY( rit1->use_count != 0 );
>+
>+  iterator it2(3);
>+  reverse_iterator rit2(it2);
>+  VERIFY( (*rit2).use_count != 0 );
>+  VERIFY( rit2->use_count != 0 );
>+  --rit2;
>+  VERIFY( (*rit2).use_count != 0 );
>+  VERIFY( rit2->use_count != 0 );
>+}
>+
>+int main() 
>+{ 
>+  test01();
>+  return 0;
>+}

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