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type_traits (__strictest_alignment): New helper struct. 

2014-06-02  Rüdiger Sonderfeld  <ruediger@c-plusplus.de>
	    Jonathan Wakely  <jwakely@redhat.com>

	* libstdc++-v3/include/std/type_traits (__strictest_alignment): New
	helper struct.
	(aligned_union): New struct (C++11).
	(aligned_union_t): New type alias (C++14).
	* doc/xml/manual/status_cxx2011.xml: Update.
	* libstdc++-v3/testsuite/20_util/aligned_union/1.cc: New file.
	* testsuite/20_util/declval/requirements/1_neg.cc: Adjust dg-error
	line number.

Co-Authored-By: Jonathan Wakely <jwakely@redhat.com>

From-SVN: r211137
This commit is contained in:
Rüdiger Sonderfeld 2014-06-02 13:55:14 +00:00 committed by Jonathan Wakely
parent ae48824a79
commit d371802725
5 changed files with 136 additions and 4 deletions
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12
libstdc++-v3/ChangeLog
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@ -1,3 +1,15 @@
2014-06-02 Rüdiger Sonderfeld <ruediger@c-plusplus.de>
Jonathan Wakely <jwakely@redhat.com>
* libstdc++-v3/include/std/type_traits (__strictest_alignment): New
helper struct.
(aligned_union): New struct (C++11).
(aligned_union_t): New type alias (C++14).
* doc/xml/manual/status_cxx2011.xml: Update.
* libstdc++-v3/testsuite/20_util/aligned_union/1.cc: New file.
* testsuite/20_util/declval/requirements/1_neg.cc: Adjust dg-error
line number.
2014-06-01 Jonathan Wakely <jwakely@redhat.com>
PR libstdc++/61374

5
libstdc++-v3/doc/xml/manual/status_cxx2011.xml
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@ -871,11 +871,10 @@ particular release.
<entry/>
</row>
<row>
<?dbhtml bgcolor="#B0B0B0" ?>
<entry>20.9.7.6</entry>
<entry>Other transformations</entry>
<entry>Partial</entry>
<entry>Missing <code>aligned_union</code>.</entry>
<entry>Y</entry>
<entry/>
</row>
<row>
<entry>20.10</entry>

49
libstdc++-v3/include/std/type_traits
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@ -1870,6 +1870,52 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
};
};
template <typename... _Types>
struct __strictest_alignment
{
static const size_t _S_alignment = 0;
static const size_t _S_size = 0;
};
template <typename _Tp, typename... _Types>
struct __strictest_alignment<_Tp, _Types...>
{
static const size_t _S_alignment =
alignof(_Tp) > __strictest_alignment<_Types...>::_S_alignment
? alignof(_Tp) : __strictest_alignment<_Types...>::_S_alignment;
static const size_t _S_size =
sizeof(_Tp) > __strictest_alignment<_Types...>::_S_size
? sizeof(_Tp) : __strictest_alignment<_Types...>::_S_size;
};
/**
* @brief Provide aligned storage for types.
*
* [meta.trans.other]
*
* Provides aligned storage for any of the provided types of at
* least size _Len.
*
* @see aligned_storage
*/
template <size_t _Len, typename... _Types>
struct aligned_union
{
private:
static_assert(sizeof...(_Types) != 0, "At least one type is required");
using __strictest = __strictest_alignment<_Types...>;
static const size_t _S_len = _Len > __strictest::_S_size
? _Len : __strictest::_S_size;
public:
/// The value of the strictest alignment of _Types.
static const size_t alignment_value = __strictest::_S_alignment;
/// The storage.
typedef typename aligned_storage<_S_len, alignment_value>::type type;
};
template <size_t _Len, typename... _Types>
const size_t aligned_union<_Len, _Types...>::alignment_value;
// Decay trait for arrays and functions, used for perfect forwarding
// in make_pair, make_tuple, etc.
@ -2206,6 +2252,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__alignof__(typename __aligned_storage_msa<_Len>::__type)>
using aligned_storage_t = typename aligned_storage<_Len, _Align>::type;
template <size_t _Len, typename... _Types>
using aligned_union_t = typename aligned_union<_Len, _Types...>::type;
/// Alias template for decay
template<typename _Tp>
using decay_t = typename decay<_Tp>::type;

72
libstdc++-v3/testsuite/20_util/aligned_union/1.cc Normal file
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@ -0,0 +1,72 @@
// { dg-options " -std=gnu++11 " }
// { dg-do compile }
// 2014-04-16 Rüdiger Sonderfeld <ruediger@c-plusplus.de>
// Copyright (C) 2014 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/>.
// C++11 [meta.trans.other] 20.9.7.6: aligned_union
#include <type_traits>
#include <testsuite_tr1.h>
struct MSAlignType { } __attribute__((__aligned__));
template<typename...T>
struct mymax
{
static const std::size_t alignment = 0;
static const std::size_t size = 0;
};
template<typename L, typename...T>
struct mymax<L, T...>
{
static const std::size_t alignment = alignof(L) > mymax<T...>::alignment
? alignof(L) : mymax<T...>::alignment;
static const std::size_t size = sizeof(L) > mymax<T...>::size
? sizeof(L) : mymax<T...>::size;
};
void test01()
{
using std::aligned_union;
using std::alignment_of;
using std::size_t;
using namespace __gnu_test;
const size_t max_a = mymax<char, short, int, double, int[4],
ClassType, MSAlignType>::alignment;
const size_t max_s = mymax<char, short, int, double, int[4],
ClassType, MSAlignType>::size;
typedef aligned_union<0, char, short, int, double, int[4],
ClassType, MSAlignType> au_type;
static_assert(au_type::alignment_value == max_a, "Alignment value");
static_assert(sizeof(au_type::type) >= max_s, "Storage size");
typedef aligned_union<max_s+100, char, short, int, double, int[4],
ClassType, MSAlignType> au_type2;
static_assert(sizeof(au_type2::type) >= max_s+100,
"Storage size (at least len)");
}
int main()
{
test01();
}

2
libstdc++-v3/testsuite/20_util/declval/requirements/1_neg.cc
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@ -19,7 +19,7 @@
// with this library; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
// { dg-error "static assertion failed" "" { target *-*-* } 2036 }
// { dg-error "static assertion failed" "" { target *-*-* } 2082 }
#include <utility>