Hi
Here is the patch to default implementation of std::list default
and move constructors.
I introduce _List_node_header to take care of the move
implementation and also isolate management of the optional list size
storage. I prefer it to usage of _List_node<size_t> as move constructor
seems complicated to implement with an __aligned_membuf. It also avoids
to use raw memory as-if it was a size_t without constructing it. Even if
size_t constructor is trivial I guess some memory analyser could have
complain about it.
* include/bits/stl_list.h
(_List_node_base()): Define.
(_List_node_base(_List_node_base*, _List_node_base*)): New.
(struct _List_node_header): New.
(_List_impl()): Fix noexcept qualification.
(_List_impl(_List_impl&&)): New, default.
(_List_impl(_List_impl&&, _Node_alloc_type&&)): New.
(_List_base()): Default.
(_List_base(_List_base&&)): Default.
(_List_base(_List_base&&, _Node_alloc_type&&, true_type)): New.
(_List_base(_List_base&&, _Node_alloc_type&&, false_type)): New.
(_List_base(_List_base&&, _Node_alloc_type&&)): Use latters.
(_List_base::_M_move_nodes): Adapt to use
_List_node_header._M_move_nodes.
(_List_base::_M_init): Likewise.
(list<>()): Default.
(list<>(list&&)): Default.
(list<>::_M_move_assign(list&&, true_type)): Use _M_move_nodes.
Tested under Linux x86_64.
Ok to commit ?
François
diff --git a/libstdc++-v3/include/bits/stl_list.h b/libstdc++-v3/include/bits/stl_list.h
index 232885a..7ffffe5 100644
--- a/libstdc++-v3/include/bits/stl_list.h
+++ b/libstdc++-v3/include/bits/stl_list.h
@@ -82,6 +82,17 @@ namespace std _GLIBCXX_VISIBILITY(default)
_List_node_base* _M_next;
_List_node_base* _M_prev;
+#if __cplusplus >= 201103L
+ _List_node_base() = default;
+#else
+ _List_node_base()
+ { }
+#endif
+
+ _List_node_base(_List_node_base* __next, _List_node_base* __prev)
+ : _M_next(__next), _M_prev(__prev)
+ { }
+
static void
swap(_List_node_base& __x, _List_node_base& __y) _GLIBCXX_USE_NOEXCEPT;
@@ -99,6 +110,79 @@ namespace std _GLIBCXX_VISIBILITY(default)
_M_unhook() _GLIBCXX_USE_NOEXCEPT;
};
+ /// The %list node header.
+ struct _List_node_header : public _List_node_base
+ {
+ private:
+#if _GLIBCXX_USE_CXX11_ABI
+ std::size_t _M_size;
+#endif
+
+ _List_node_base* _M_base() { return this; }
+
+ public:
+ _List_node_header() _GLIBCXX_NOEXCEPT
+ : _List_node_base(this, this)
+# if _GLIBCXX_USE_CXX11_ABI
+ , _M_size(0)
+# endif
+ { }
+
+#if __cplusplus >= 201103L
+ _List_node_header(_List_node_header&& __x) noexcept
+ : _List_node_base(__x._M_next, __x._M_prev)
+# if _GLIBCXX_USE_CXX11_ABI
+ , _M_size(__x._M_size)
+# endif
+ {
+ if (__x._M_base()->_M_next == __x._M_base())
+ this->_M_next = this->_M_prev = this;
+ else
+ {
+ this->_M_next->_M_prev = this->_M_prev->_M_next = this->_M_base();
+ __x._M_init();
+ }
+ }
+
+ void
+ _M_move_nodes(_List_node_header&& __x)
+ {
+ _List_node_base* const __xnode = __x._M_base();
+ if (__xnode->_M_next == __xnode)
+ _M_init();
+ else
+ {
+ _List_node_base* const __node = this->_M_base();
+ __node->_M_next = __xnode->_M_next;
+ __node->_M_prev = __xnode->_M_prev;
+ __node->_M_next->_M_prev = __node->_M_prev->_M_next = __node;
+ _M_set_size(__x._M_get_size());
+ __x._M_init();
+ }
+ }
+#endif
+
+#if _GLIBCXX_USE_CXX11_ABI
+ size_t _M_get_size() const { return _M_size; }
+ void _M_set_size(size_t __n) { _M_size = __n; }
+ void _M_inc_size(size_t __n) { _M_size += __n; }
+ void _M_dec_size(size_t __n) { _M_size -= __n; }
+#else
+ // dummy implementations used when the size is not stored
+ size_t _M_get_size() const { return 0; }
+ void _M_set_size(size_t) { }
+ void _M_inc_size(size_t) { }
+ void _M_dec_size(size_t) { }
+#endif
+
+ void
+ _M_init() _GLIBCXX_NOEXCEPT
+ {
+ this->_M_next = this->_M_prev = this;
+ _M_set_size(0);
+ }
+ };
+
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace detail
@@ -323,51 +407,53 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
struct _List_impl
: public _Node_alloc_type
{
-#if _GLIBCXX_USE_CXX11_ABI
- _List_node<size_t> _M_node;
-#else
- __detail::_List_node_base _M_node;
-#endif
+ __detail::_List_node_header _M_node;
- _List_impl() _GLIBCXX_NOEXCEPT
- : _Node_alloc_type(), _M_node()
+ _List_impl() _GLIBCXX_NOEXCEPT_IF( noexcept(_Node_alloc_type()) )
+ : _Node_alloc_type()
{ }
_List_impl(const _Node_alloc_type& __a) _GLIBCXX_NOEXCEPT
- : _Node_alloc_type(__a), _M_node()
+ : _Node_alloc_type(__a)
{ }
#if __cplusplus >= 201103L
+ _List_impl(_List_impl&&) = default;
+
+ _List_impl(_List_impl&& __x, _Node_alloc_type&& __a)
+ : _Node_alloc_type(std::move(__a)), _M_node(std::move(__x._M_node))
+ { }
+
_List_impl(_Node_alloc_type&& __a) noexcept
- : _Node_alloc_type(std::move(__a)), _M_node()
+ : _Node_alloc_type(std::move(__a))
{ }
#endif
};
_List_impl _M_impl;
-#if _GLIBCXX_USE_CXX11_ABI
- size_t _M_get_size() const { return *_M_impl._M_node._M_valptr(); }
+ size_t
+ _M_get_size() const { return _M_impl._M_node._M_get_size(); }
- void _M_set_size(size_t __n) { *_M_impl._M_node._M_valptr() = __n; }
+ void
+ _M_set_size(size_t __n) { _M_impl._M_node._M_set_size(__n); }
- void _M_inc_size(size_t __n) { *_M_impl._M_node._M_valptr() += __n; }
+ void
+ _M_inc_size(size_t __n) { _M_impl._M_node._M_inc_size(__n); }
- void _M_dec_size(size_t __n) { *_M_impl._M_node._M_valptr() -= __n; }
+ void
+ _M_dec_size(size_t __n) { _M_impl._M_node._M_dec_size(__n); }
+#if _GLIBCXX_USE_CXX11_ABI
size_t
_M_distance(const __detail::_List_node_base* __first,
const __detail::_List_node_base* __last) const
{ return _S_distance(__first, __last); }
// return the stored size
- size_t _M_node_count() const { return *_M_impl._M_node._M_valptr(); }
+ size_t _M_node_count() const { return _M_impl._M_node._M_get_size(); }
#else
// dummy implementations used when the size is not stored
- size_t _M_get_size() const { return 0; }
- void _M_set_size(size_t) { }
- void _M_inc_size(size_t) { }
- void _M_dec_size(size_t) { }
size_t _M_distance(const void*, const void*) const { return 0; }
// count the number of nodes
@@ -397,44 +483,41 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
_M_get_Node_allocator() const _GLIBCXX_NOEXCEPT
{ return _M_impl; }
- _List_base()
- : _M_impl()
- { _M_init(); }
+#if __cplusplus >= 201103L
+ _List_base() = default;
+#else
+ _List_base() { }
+#endif
_List_base(const _Node_alloc_type& __a) _GLIBCXX_NOEXCEPT
: _M_impl(__a)
- { _M_init(); }
+ { }
#if __cplusplus >= 201103L
- _List_base(_List_base&& __x) noexcept
- : _M_impl(std::move(__x._M_get_Node_allocator()))
- { _M_move_nodes(std::move(__x)); }
+ _List_base(_List_base&&) = default;
- _List_base(_List_base&& __x, _Node_alloc_type&& __a)
+ private:
+ _List_base(_List_base&& __x, _Node_alloc_type&& __a, true_type)
+ : _M_impl(std::move(__x._M_impl), std::move(__a))
+ { }
+
+ _List_base(_List_base&& __x, _Node_alloc_type&& __a, false_type)
: _M_impl(std::move(__a))
{
if (__x._M_get_Node_allocator() == _M_get_Node_allocator())
_M_move_nodes(std::move(__x));
- else
- _M_init(); // Caller must move individual elements.
+ // else Caller must move individual elements.
}
+ public:
+ _List_base(_List_base&& __x, _Node_alloc_type&& __a)
+ : _List_base(std::move(__x), std::move(__a),
+ typename _Node_alloc_traits::is_always_equal{})
+ { }
+
void
_M_move_nodes(_List_base&& __x)
- {
- auto* const __xnode = std::__addressof(__x._M_impl._M_node);
- if (__xnode->_M_next == __xnode)
- _M_init();
- else
- {
- auto* const __node = std::__addressof(_M_impl._M_node);
- __node->_M_next = __xnode->_M_next;
- __node->_M_prev = __xnode->_M_prev;
- __node->_M_next->_M_prev = __node->_M_prev->_M_next = __node;
- _M_set_size(__x._M_get_size());
- __x._M_init();
- }
- }
+ { _M_impl._M_node._M_move_nodes(std::move(__x._M_impl._M_node)); }
#endif
// This is what actually destroys the list.
@@ -446,11 +529,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
void
_M_init() _GLIBCXX_NOEXCEPT
- {
- this->_M_impl._M_node._M_next = &this->_M_impl._M_node;
- this->_M_impl._M_node._M_prev = &this->_M_impl._M_node;
- _M_set_size(0);
- }
+ { this->_M_impl._M_node._M_init(); }
};
/**
@@ -586,11 +665,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
/**
* @brief Creates a %list with no elements.
*/
- list()
#if __cplusplus >= 201103L
- noexcept(is_nothrow_default_constructible<_Node_alloc_type>::value)
+ list() = default;
+#else
+ list() { }
#endif
- : _Base() { }
/**
* @brief Creates a %list with no elements.
@@ -657,13 +736,11 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
#if __cplusplus >= 201103L
/**
* @brief %List move constructor.
- * @param __x A %list of identical element and allocator types.
*
- * The newly-created %list contains the exact contents of @a __x.
- * The contents of @a __x are a valid, but unspecified %list.
+ * The newly-created %list contains the exact contents of the moved
+ * instance. The contents of @a __x are a valid, but unspecified %list.
*/
- list(list&& __x) noexcept
- : _Base(std::move(__x)) { }
+ list(list&&) = default;
/**
* @brief Builds a %list from an initializer_list
@@ -1838,17 +1915,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
_M_move_assign(list&& __x, true_type) noexcept
{
this->_M_clear();
- if (__x.empty())
- this->_M_init();
- else
- {
- this->_M_impl._M_node._M_next = __x._M_impl._M_node._M_next;
- this->_M_impl._M_node._M_next->_M_prev = &this->_M_impl._M_node;
- this->_M_impl._M_node._M_prev = __x._M_impl._M_node._M_prev;
- this->_M_impl._M_node._M_prev->_M_next = &this->_M_impl._M_node;
- this->_M_set_size(__x._M_get_size());
- __x._M_init();
- }
+ this->_M_move_nodes(std::move(__x));
std::__alloc_on_move(this->_M_get_Node_allocator(),
__x._M_get_Node_allocator());
}
@@ -1983,12 +2050,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_GLIBCXX_STD_C::_List_const_iterator<_Tp> __last,
input_iterator_tag)
{
- typedef _GLIBCXX_STD_C::_List_node<size_t> _Sentinel;
+ typedef __detail::_List_node_header _Sentinel;
_GLIBCXX_STD_C::_List_const_iterator<_Tp> __beyond = __last;
++__beyond;
bool __whole = __first == __beyond;
if (__builtin_constant_p (__whole) && __whole)
- return *static_cast<const _Sentinel*>(__last._M_node)->_M_valptr();
+ return static_cast<const _Sentinel*>(__last._M_node)->_M_get_size();
ptrdiff_t __n = 0;
while (__first != __last)
diff --git a/libstdc++-v3/testsuite/23_containers/list/allocator/default_init.cc b/libstdc++-v3/testsuite/23_containers/list/allocator/default_init.cc
new file mode 100644
index 0000000..0604e06
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/list/allocator/default_init.cc
@@ -0,0 +1,71 @@
+// Copyright (C) 2017 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-do run { target c++11 } }
+// { dg-options "-O0" }
+// { dg-xfail-run-if "PR c++/65816" { *-*-* } }
+
+#include <list>
+#include <testsuite_hooks.h>
+#include <testsuite_allocator.h>
+
+#include <ext/aligned_buffer.h>
+
+using T = int;
+
+using __gnu_test::default_init_allocator;
+
+void test01()
+{
+ typedef default_init_allocator<T> alloc_type;
+ typedef std::list<T, alloc_type> test_type;
+
+ __gnu_cxx::__aligned_buffer<test_type> buf;
+ __builtin_memset(buf._M_addr(), ~0, sizeof(test_type));
+
+ VERIFY( buf._M_ptr()->get_allocator().state != 0 );
+
+ test_type *tmp = ::new(buf._M_addr()) test_type();
+
+ VERIFY( tmp->get_allocator().state == 0 );
+
+ tmp->~test_type();
+}
+
+void test02()
+{
+ typedef default_init_allocator<T> alloc_type;
+ typedef std::list<T, alloc_type> test_type;
+
+ __gnu_cxx::__aligned_buffer<test_type> buf;
+ __builtin_memset(buf._M_addr(), ~0, sizeof(test_type));
+
+ VERIFY( buf._M_ptr()->get_allocator().state != 0 );
+
+ test_type *tmp = ::new(buf._M_addr()) test_type;
+
+ VERIFY( tmp->get_allocator().state == 0 );
+
+ tmp->~test_type();
+}
+
+int main()
+{
+ test01();
+ test02();
+ return 0;
+}
