[libcxx] r203587 - Implement LWG 2360: 'reverse_iterator::operator*() is unimplementable'. Note that this is a (small) behavior change in the library. Reverse iterators whose base iterators' operator* return references to 'within themselves' have been sacrificed to the greater goal of avoiding data races.
Marshall Clow
mclow.lists at gmail.com
Tue Mar 11 10:16:17 PDT 2014
Author: marshall
Date: Tue Mar 11 12:16:17 2014
New Revision: 203587
URL: http://llvm.org/viewvc/llvm-project?rev=203587&view=rev
Log:
Implement LWG 2360: 'reverse_iterator::operator*() is unimplementable'. Note that this is a (small) behavior change in the library. Reverse iterators whose base iterators' operator* return references to 'within themselves' have been sacrificed to the greater goal of avoiding data races.
Modified:
libcxx/trunk/include/iterator
libcxx/trunk/test/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op.star/op_star.pass.cpp
libcxx/trunk/test/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opref/op_arrow.pass.cpp
libcxx/trunk/www/cxx1y_status.html
Modified: libcxx/trunk/include/iterator
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/iterator?rev=203587&r1=203586&r2=203587&view=diff
==============================================================================
--- libcxx/trunk/include/iterator (original)
+++ libcxx/trunk/include/iterator Tue Mar 11 12:16:17 2014
@@ -536,8 +536,6 @@ class _LIBCPP_TYPE_VIS_ONLY reverse_iter
typename iterator_traits<_Iter>::pointer,
typename iterator_traits<_Iter>::reference>
{
-private:
- mutable _Iter __t;
protected:
_Iter current;
public:
@@ -547,11 +545,11 @@ public:
typedef typename iterator_traits<_Iter>::pointer pointer;
_LIBCPP_INLINE_VISIBILITY reverse_iterator() : current() {}
- _LIBCPP_INLINE_VISIBILITY explicit reverse_iterator(_Iter __x) : __t(__x), current(__x) {}
+ _LIBCPP_INLINE_VISIBILITY explicit reverse_iterator(_Iter __x) : current(__x) {}
template <class _Up> _LIBCPP_INLINE_VISIBILITY reverse_iterator(const reverse_iterator<_Up>& __u)
- : __t(__u.base()), current(__u.base()) {}
+ : current(__u.base()) {}
_LIBCPP_INLINE_VISIBILITY _Iter base() const {return current;}
- _LIBCPP_INLINE_VISIBILITY reference operator*() const {__t = current; return *--__t;}
+ _LIBCPP_INLINE_VISIBILITY reference operator*() const {_Iter __tmp = current; return *--__tmp;}
_LIBCPP_INLINE_VISIBILITY pointer operator->() const {return _VSTD::addressof(operator*());}
_LIBCPP_INLINE_VISIBILITY reverse_iterator& operator++() {--current; return *this;}
_LIBCPP_INLINE_VISIBILITY reverse_iterator operator++(int)
Modified: libcxx/trunk/test/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op.star/op_star.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op.star/op_star.pass.cpp?rev=203587&r1=203586&r2=203587&view=diff
==============================================================================
--- libcxx/trunk/test/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op.star/op_star.pass.cpp (original)
+++ libcxx/trunk/test/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op.star/op_star.pass.cpp Tue Mar 11 12:16:17 2014
@@ -15,6 +15,8 @@
// Be sure to respect LWG 198:
// http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#198
+// LWG 198 was superseded by LWG 2360
+// http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2360
#include <iterator>
#include <cassert>
@@ -31,26 +33,6 @@ public:
};
template <class It>
-class weird_iterator
-{
- It it_;
-public:
- typedef It value_type;
- typedef std::bidirectional_iterator_tag iterator_category;
- typedef std::ptrdiff_t difference_type;
- typedef It* pointer;
- typedef It& reference;
-
- weird_iterator() {}
- explicit weird_iterator(It it) : it_(it) {}
- ~weird_iterator() {it_ = It();}
-
- reference operator*() {return it_;}
-
- weird_iterator& operator--() {return *this;}
-};
-
-template <class It>
void
test(It i, typename std::iterator_traits<It>::value_type x)
{
@@ -60,7 +42,6 @@ test(It i, typename std::iterator_traits
int main()
{
- test(weird_iterator<A>(A()), A());
A a;
test(&a+1, A());
}
Modified: libcxx/trunk/test/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opref/op_arrow.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opref/op_arrow.pass.cpp?rev=203587&r1=203586&r2=203587&view=diff
==============================================================================
--- libcxx/trunk/test/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opref/op_arrow.pass.cpp (original)
+++ libcxx/trunk/test/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opref/op_arrow.pass.cpp Tue Mar 11 12:16:17 2014
@@ -15,6 +15,9 @@
// Be sure to respect LWG 198:
// http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#198
+// LWG 198 was superseded by LWG 2360
+// http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2360
+
#include <iterator>
#include <list>
@@ -34,27 +37,6 @@ public:
};
template <class It>
-class weird_iterator
-{
- It it_;
-public:
- typedef It value_type;
- typedef std::bidirectional_iterator_tag iterator_category;
- typedef std::ptrdiff_t difference_type;
- typedef It* pointer;
- typedef It& reference;
-
- weird_iterator() {}
- explicit weird_iterator(It it) : it_(it) {}
- ~weird_iterator() {it_ = It();}
-
- reference operator*() {return it_;}
- pointer operator->() {return &it_;}
-
- weird_iterator& operator--() {return *this;}
-};
-
-template <class It>
void
test(It i, typename std::iterator_traits<It>::value_type x)
{
@@ -79,7 +61,6 @@ public:
int main()
{
- test(weird_iterator<A>(A()), A());
A a;
test(&a+1, A());
Modified: libcxx/trunk/www/cxx1y_status.html
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/www/cxx1y_status.html?rev=203587&r1=203586&r2=203587&view=diff
==============================================================================
--- libcxx/trunk/www/cxx1y_status.html (original)
+++ libcxx/trunk/www/cxx1y_status.html Tue Mar 11 12:16:17 2014
@@ -265,7 +265,7 @@
<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2356">2356</a></td><td>Stability of erasure in unordered associative containers</td><td>Issaquah</td><td>Complete</td></tr>
<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2357">2357</a></td><td>Remaining "Assignable" requirement</td><td>Issaquah</td><td>Complete</td></tr>
<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2359">2359</a></td><td>How does regex_constants::nosubs affect basic_regex::mark_count()?</td><td>Issaquah</td><td>Complete</td></tr>
- <tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2360">2360</a></td><td>reverse_iterator::operator*() is unimplementable</td><td>Issaquah</td><td></td></tr>
+ <tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2360">2360</a></td><td>reverse_iterator::operator*() is unimplementable</td><td>Issaquah</td><td>Complete</td></tr>
<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2104">2104</a></td><td>unique_lock move-assignment should not be noexcept</td><td>Issaquah</td><td></td></tr>
<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2186">2186</a></td><td>Incomplete action on async/launch::deferred</td><td>Issaquah</td><td></td></tr>
<tr><td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2075">2075</a></td><td>Progress guarantees, lock-free property, and scheduling assumptions</td><td>Issaquah</td><td></td></tr>
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