[v3] Implement pointer_traits and allocator_traits

[v3] Implement pointer_traits and allocator_traits

[Jonathan Wakely]

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2011-05-28  Jonathan Wakely  <jwakely.gcc@gmail.com>

        * include/Makefile.am: Add new ptr_traits.h header.
        * include/Makefile.in: Regenerate.
        * include/bits/ptr_traits.h (pointer_traits): New.
        * include/bits/allocator.h (allocator_traits): Add.
        * include/ext/array_allocator.h (construct, destroy): Update C++0x
        versions.
        * include/ext/bitmap_allocator.h (construct, destroy): Likewise.
        * include/ext/extptr_allocator.h (construct, destroy): Likewise.
        * include/ext/malloc_allocator.h (construct, destroy): Likewise.
        * include/ext/mt_allocator.h (construct, destroy): Likewise.
        * include/ext/new_allocator.h (construct, destroy): Likewise.
        * include/ext/pool_allocator.h (construct, destroy): Likewise.
        * include/ext/throw_allocator.h (construct, destroy): Likewise.
        * testsuite/20_util/allocator_traits/requirements/typedefs.cc: New.
        * testsuite/20_util/allocator_traits/requirements/
        explicit_instantiation.cc: New.
        * testsuite/20_util/allocator_traits/members/max_size.cc: New.
        * testsuite/20_util/allocator_traits/members/select.cc: New.
        * testsuite/20_util/allocator_traits/members/construct.cc: New.
        * testsuite/20_util/allocator_traits/members/allocate_hint.cc: New.
        * testsuite/20_util/allocator_traits/members/destroy.cc: New.
        * testsuite/20_util/pointer_traits/requirements/typedefs.cc: New.
        * testsuite/20_util/pointer_traits/requirements/
        explicit_instantiation.cc: New.

Tested x86_64-linux, committed to trunk

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Index: include/Makefile.am
===================================================================
--- include/Makefile.am	(revision 174358)
+++ include/Makefile.am	(working copy)
@@ -119,6 +119,7 @@
 	${bits_srcdir}/ostream.tcc \
 	${bits_srcdir}/ostream_insert.h \
 	${bits_srcdir}/postypes.h \
+	${bits_srcdir}/ptr_traits.h \
 	${bits_srcdir}/random.h \
 	${bits_srcdir}/random.tcc \
 	${bits_srcdir}/range_access.h \
Index: include/bits/ptr_traits.h
===================================================================
--- include/bits/ptr_traits.h	(revision 0)
+++ include/bits/ptr_traits.h	(revision 0)
@@ -0,0 +1,222 @@
+// Pointer Traits -*- C++ -*-
+
+// Copyright (C) 2011 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.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file bits/ptr_traits.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{memory}
+ */
+
+#ifndef _PTR_TRAITS_H
+#define _PTR_TRAITS_H 1
+
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+
+#include <type_traits> // For _GLIBCXX_HAS_NESTED_TYPE
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+_GLIBCXX_HAS_NESTED_TYPE(element_type)
+_GLIBCXX_HAS_NESTED_TYPE(difference_type)
+
+  template<typename _Tp, bool = __has_element_type<_Tp>::value>
+    struct __ptrtr_elt_type;
+
+  template<typename _Tp>
+    struct __ptrtr_elt_type<_Tp, true>
+    {
+      typedef typename _Tp::element_type __type;
+    };
+
+  template<template<typename, typename...> class _SomePtr, typename _Tp,
+            typename... _Args>
+    struct __ptrtr_elt_type<_SomePtr<_Tp, _Args...>, false>
+    {
+      typedef _Tp __type;
+    };
+
+  template<typename _Tp, bool = __has_difference_type<_Tp>::value>
+    struct __ptrtr_diff_type
+    {
+      typedef typename _Tp::difference_type __type;
+    };
+
+  template<typename _Tp>
+    struct __ptrtr_diff_type<_Tp, false>
+    {
+      typedef ptrdiff_t __type;
+    };
+
+  template<typename _Ptr, typename _Up>
+    class __ptrtr_rebind_helper
+    {
+      template<typename _Ptr2, typename _Up2>
+	static constexpr bool
+       	_S_chk(typename _Ptr2::template rebind<_Up2>*)
+       	{ return true; }
+
+      template<typename, typename>
+        static constexpr bool
+       	_S_chk(...)
+       	{ return false; }
+
+    public:
+      static const bool __value = _S_chk<_Ptr, _Up>(nullptr);
+    };
+
+  // hack to use _Tp::__rebind<_Up>::__type instead if that exists
+  template<typename _Ptr, typename _Up>
+    class __ptrtr_rebind_helper2
+    {
+      template<typename _Ptr2, typename _Up2>
+	static constexpr bool
+       	_S_chk(typename _Ptr2::template __rebind<_Up2>::__type*)
+	{ return true; }
+
+      template<typename, typename>
+        static constexpr bool
+       	_S_chk(...)
+       	{ return false; }
+
+    public:
+      static const bool __value = _S_chk<_Ptr, _Up>(nullptr);
+    };
+
+  /* TODO: remove second bool when alias templates are supported */
+  template<typename _Tp, typename _Up,
+           bool = __ptrtr_rebind_helper<_Tp, _Up>::value,
+           bool = __ptrtr_rebind_helper2<_Tp, _Up>::value>
+    struct __ptrtr_rebind;
+
+  template<typename _Tp, typename _Up, bool _B2>
+    struct __ptrtr_rebind<_Tp, _Up, true, _B2>
+    {
+      typedef typename _Tp::template rebind<_Up> __type;
+    };
+
+  /* TODO: remove this when alias templates are supported */
+  template<typename _Tp, typename _Up>
+    struct __ptrtr_rebind<_Tp, _Up, false, true>
+    {
+      typedef typename _Tp::template __rebind<_Up>::__type __type;
+    };
+
+  template<template<typename, typename...> class _SomePtr, typename _Up,
+            typename _Tp, typename... _Args>
+    struct __ptrtr_rebind<_SomePtr<_Tp, _Args...>, _Up, false, false>
+    {
+      typedef _SomePtr<_Up, _Args...> __type;
+    };
+
+  template<typename _Tp, typename = typename remove_cv<_Tp>::type>
+    struct __ptrtr_not_void
+    {
+      typedef _Tp __type;
+    };
+
+  template<typename _Tp>
+    struct __ptrtr_not_void<_Tp, void>
+    {
+      struct __type { };
+    };
+
+  template<typename _Ptr>
+    class __ptrtr_pointer_to
+    {
+      typedef typename __ptrtr_elt_type<_Ptr>::__type   __orig_type;
+      typedef typename __ptrtr_not_void<__orig_type>::__type __element_type;
+
+    public:
+      static _Ptr pointer_to(__element_type& __e)
+      { return _Ptr::pointer_to(__e); }
+    };
+
+  /**
+   * @brief  Uniform interface to all pointer-like types
+   * @ingroup pointer_abstractions
+  */
+  template<typename _Ptr>
+    struct pointer_traits : __ptrtr_pointer_to<_Ptr>
+    {
+      /// The pointer type
+      typedef _Ptr                                      pointer;
+      /// The type pointed to
+      typedef typename __ptrtr_elt_type<_Ptr>::__type   element_type;
+      /// Type used to represent the difference between two pointers
+      typedef typename __ptrtr_diff_type<_Ptr>::__type  difference_type;
+
+    private:
+      /* TODO: replace __rebind<U> with alias template rebind<U> */
+      /*
+      template<typename _Up>
+        using rebind<_Up> = typename __ptrtr_rebind<_Ptr, _Up>::__type;
+      */
+      template<typename _Up>
+       	struct __rebind
+        { typedef typename __ptrtr_rebind<_Ptr, _Up>::__type __type; };
+
+      // allocator_traits needs to use __rebind
+      template<typename> struct allocator_traits;
+      template<typename, typename> class __ptrtr_rebind_helper2;
+    };
+
+  /**
+   * @brief  Partial specialization for built-in pointers.
+   * @ingroup pointer_abstractions
+  */
+  template<typename _Tp>
+    struct pointer_traits<_Tp*>
+    {
+      /// The pointer type
+      typedef _Tp* pointer;
+      /// The type pointed to
+      typedef _Tp  element_type;
+      /// Type used to represent the difference between two pointers
+      typedef ptrdiff_t difference_type;
+
+      /* TODO: replace __rebind<U> with alias template rebind<U> */
+      /*
+      template<typename _Up>
+        using rebind<_Up> = U*;
+      */
+      template<typename U>
+       	struct __rebind { typedef U* __type; };
+
+      /**
+       *  @brief  Obtain a pointer to an object
+       *  @param  r  A reference to an object of type @c element_type
+       *  @return @c addressof(r)
+      */
+      static pointer
+      pointer_to(typename __ptrtr_not_void<element_type>::__type& __r)
+      { return std::addressof(__r); }
+    };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+
+#endif
+
+#endif
Index: include/bits/allocator.h
===================================================================
--- include/bits/allocator.h	(revision 174358)
+++ include/bits/allocator.h	(working copy)
@@ -48,7 +48,9 @@
 #include <bits/c++allocator.h>
 
 #ifdef __GXX_EXPERIMENTAL_CXX0X__
+#include <bits/ptr_traits.h>
 #include <type_traits> // For _GLIBCXX_HAS_NESTED_TYPE
+#include <limits>
 #endif
 
 namespace std _GLIBCXX_VISIBILITY(default)
@@ -85,8 +87,8 @@
    * @brief  The @a standard allocator, as per [20.4].
    * @ingroup allocators
    *
-   *  Further details:
-   *  http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt04ch11.html
+   *  See http://gcc.gnu.org/onlinedocs/libstdc++/manual/bk01pt04ch11.html
+   *  for further details.
    */
   template<typename _Tp>
     class allocator: public __glibcxx_base_allocator<_Tp>
@@ -185,7 +187,7 @@
   // A very basic implementation for now.  In general we have to wait for
   // the availability of the infrastructure described in N2983:  we should
   // try when either T has a move constructor which cannot throw or T is
-  // CopyContructible.
+  // CopyConstructible.
   // NB: This code doesn't properly belong here, we should find a more
   // suited place common to std::vector and std::deque.
   template<typename _Tp,
@@ -231,6 +233,404 @@
 			       __uses_allocator_helper<_Tp, _Alloc>::value>
     { };
 
+  template<typename _Alloc, typename _Tp>
+    class __alloctr_rebind_helper
+    {
+      template<typename _Alloc2, typename _Tp2>
+	static constexpr bool
+       	_S_chk(typename _Alloc2::template rebind<_Tp2>::other*)
+	{ return true; }
+
+      template<typename, typename>
+        static constexpr bool
+       	_S_chk(...)
+       	{ return false; }
+
+    public:
+      static const bool __value = _S_chk<_Alloc, _Tp>(nullptr);
+    };
+
+  template<typename _Alloc, typename _Tp,
+           bool = __alloctr_rebind_helper<_Alloc, _Tp>::__value>
+    struct __alloctr_rebind;
+
+  template<typename _Alloc, typename _Tp>
+    struct __alloctr_rebind<_Alloc, _Tp, true>
+    {
+      typedef typename _Alloc::template rebind<_Tp>::other __type;
+    };
+
+  template<template<typename, typename...> class _Alloc, typename _Tp,
+            typename _Up, typename... _Args>
+    struct __alloctr_rebind<_Alloc<_Up, _Args...>, _Tp, false>
+    {
+      typedef _Alloc<_Tp, _Args...> __type;
+    };
+
+  /**
+   * @brief  Uniform interface to all allocator types.
+   * @ingroup allocators
+  */
+  template<typename _Alloc>
+    struct allocator_traits
+    {
+      /// The allocator type
+      typedef _Alloc allocator_type;
+      /// The allocated type
+      typedef typename _Alloc::value_type value_type;
+
+#define _GLIBCXX_ALLOC_TR_NESTED_TYPE(_NTYPE, _ALT) \
+  private: \
+  template<typename _Tp> \
+    static typename _Tp::_NTYPE _S_##_NTYPE##_helper(_Tp*); \
+  static _ALT _S_##_NTYPE##_helper(...); \
+    typedef decltype(_S_##_NTYPE##_helper((_Alloc*)0)) __##_NTYPE; \
+  public:
+
+_GLIBCXX_ALLOC_TR_NESTED_TYPE(pointer, value_type*)
+
+      /**
+       * @brief   The allocator's pointer type.
+       *
+       * @c Alloc::pointer if that type exists, otherwise @c value_type*
+      */
+      typedef __pointer pointer;
+
+// TODO: Use pointer_traits::rebind alias template.
+
+_GLIBCXX_ALLOC_TR_NESTED_TYPE(const_pointer,
+  typename pointer_traits<pointer>::template __rebind<const value_type>::__type)
+
+      /**
+       * @brief   The allocator's const pointer type.
+       *
+       * @c Alloc::const_pointer if that type exists, otherwise
+       * <tt> pointer_traits<pointer>::rebind<const value_type> </tt>
+      */
+      typedef __const_pointer const_pointer;
+
+_GLIBCXX_ALLOC_TR_NESTED_TYPE(void_pointer,
+  typename pointer_traits<pointer>::template __rebind<void>::__type)
+
+      /**
+       * @brief   The allocator's void pointer type.
+       *
+       * @c Alloc::void_pointer if that type exists, otherwise
+       * <tt> pointer_traits<pointer>::rebind<void> </tt>
+      */
+      typedef __void_pointer void_pointer;
+
+_GLIBCXX_ALLOC_TR_NESTED_TYPE(const_void_pointer,
+  typename pointer_traits<pointer>::template __rebind<const void>::__type)
+
+      /**
+       * @brief   The allocator's const void pointer type.
+       *
+       * @c Alloc::const_void_pointer if that type exists, otherwise
+       * <tt> pointer_traits<pointer>::rebind<const void> </tt>
+      */
+      typedef __const_void_pointer const_void_pointer;
+
+_GLIBCXX_ALLOC_TR_NESTED_TYPE(difference_type,
+                              typename pointer_traits<pointer>::difference_type)
+
+      /**
+       * @brief   The allocator's difference type
+       *
+       * @c Alloc::difference_type if that type exists, otherwise
+       * <tt> pointer_traits<pointer>::difference_type </tt>
+      */
+      typedef __difference_type difference_type;
+
+_GLIBCXX_ALLOC_TR_NESTED_TYPE(size_type,
+                              typename make_unsigned<difference_type>::type)
+
+      /**
+       * @brief   The allocator's size type
+       *
+       * @c Alloc::size_type if that type exists, otherwise
+       * <tt> make_unsigned<difference_type>::type </tt>
+      */
+      typedef __size_type size_type;
+
+_GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_copy_assignment,
+                              false_type)
+
+      /**
+       * @brief   How the allocator is propagated on copy assignment
+       *
+       * @c Alloc::propagate_on_container_copy_assignment if that type exists,
+       * otherwise @c false_type
+      */
+      typedef __propagate_on_container_copy_assignment
+       	propagate_on_container_copy_assignment;
+
+_GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_move_assignment,
+                              false_type)
+
+      /**
+       * @brief   How the allocator is propagated on move assignment
+       *
+       * @c Alloc::propagate_on_container_move_assignment if that type exists,
+       * otherwise @c false_type
+      */
+      typedef __propagate_on_container_move_assignment
+       	propagate_on_container_move_assignment;
+
+_GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_swap,
+                              false_type)
+
+      /**
+       * @brief   How the allocator is propagated on swap
+       *
+       * @c Alloc::propagate_on_container_swap if that type exists,
+       * otherwise @c false_type
+      */
+      typedef __propagate_on_container_swap propagate_on_container_swap;
+
+#undef _GLIBCXX_ALLOC_TR_NESTED_TYPE
+
+      /* TODO: use template alias 
+      template<typename _Tp>
+        using rebind_alloc = __alloctr_rebind<_Alloc, _Tp>::__type;
+      template<typename _Tp>
+        using rebind_traits = allocator_traits<rebind_alloc<_Tp>>;
+      */
+      template<typename _Tp>
+        struct __rebind_alloc
+	{
+  	  typedef typename __alloctr_rebind<_Alloc, _Tp>::__type __type;
+       	};
+
+      template<typename _Tp>
+        struct __rebind_traits
+	{
+	  typedef allocator_traits<typename __rebind_alloc<_Tp>::__type> __type;
+	};
+
+    private:
+      template<typename _Alloc2>
+	struct __allocate_helper
+	{
+	  template<typename _Alloc3,
+	    typename = decltype(std::declval<_Alloc3*>()->allocate(
+		  std::declval<size_type>(),
+		  std::declval<const_void_pointer>()))>
+	    static true_type __test(int);
+
+	  template<typename>
+	    static false_type __test(...);
+
+	  typedef decltype(__test<_Alloc>(0)) type;
+	  static const bool value = type::value;
+	};
+
+      template<typename _Alloc2>
+	static typename
+       	enable_if<__allocate_helper<_Alloc2>::value, pointer>::type
+       	_S_allocate(_Alloc2& __a, size_type __n, const_void_pointer __hint)
+	{ return __a.allocate(__n, __hint); }
+
+      template<typename _Alloc2>
+	static typename
+       	enable_if<!__allocate_helper<_Alloc2>::value, pointer>::type
+       	_S_allocate(_Alloc2& __a, size_type __n, ...)
+	{ return __a.allocate(__n); }
+
+      template<typename _Tp, typename... _Args>
+	struct __construct_helper
+	{
+	  template<typename _Alloc2,
+	    typename = decltype(std::declval<_Alloc2*>()->construct(
+		  std::declval<_Tp*>(), std::declval<_Args>()...))>
+	    static true_type __test(int);
+
+	  template<typename>
+	    static false_type __test(...);
+
+	  typedef decltype(__test<_Alloc>(0)) type;
+	  static const bool value = type::value;
+	};
+
+      template<typename _Tp, typename... _Args>
+	static typename
+       	enable_if<__construct_helper<_Tp, _Args...>::value, void>::type
+       	_S_construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
+	{ __a.construct(__p, std::forward<_Args>(__args)...); }
+
+      template<typename _Tp, typename... _Args>
+	static typename
+       	enable_if<!__construct_helper<_Tp, _Args...>::value, void>::type
+       	_S_construct(_Alloc&, _Tp* __p, _Args&&... __args)
+	{ ::new((void*)__p) _Tp(std::forward<_Args>(__args)...); }
+
+      template<typename _Tp>
+	struct __destroy_helper
+	{
+	  template<typename _Alloc2,
+	    typename = decltype(std::declval<_Alloc2*>()->destroy(
+		  std::declval<_Tp*>()))>
+	    static true_type __test(int);
+
+	  template<typename>
+	    static false_type __test(...);
+
+	  typedef decltype(__test<_Alloc>(0)) type;
+	  static const bool value = type::value;
+	};
+
+      template<typename _Tp>
+	static typename enable_if<__destroy_helper<_Tp>::value, void>::type
+       	_S_destroy(_Alloc& __a, _Tp* __p)
+	{ __a.destroy(__p); }
+
+      template<typename _Tp>
+	static typename enable_if<!__destroy_helper<_Tp>::value, void>::type
+       	_S_destroy(_Alloc&, _Tp* __p)
+	{ __p->~_Tp(); }
+
+      template<typename _Alloc2>
+	struct __maxsize_helper
+	{
+	  template<typename _Alloc3,
+	    typename = decltype(std::declval<_Alloc3*>()->max_size())>
+	    static true_type __test(int);
+
+	  template<typename>
+	    static false_type __test(...);
+
+	  typedef decltype(__test<_Alloc2>(0)) type;
+	  static const bool value = type::value;
+	};
+
+      template<typename _Alloc2>
+	static typename
+       	enable_if<__maxsize_helper<_Alloc2>::value, size_type>::type
+       	_S_max_size(_Alloc2& __a)
+	{ return __a.max_size(); }
+
+      template<typename _Alloc2>
+	static typename
+       	enable_if<!__maxsize_helper<_Alloc2>::value, size_type>::type
+	_S_max_size(_Alloc2&)
+	{ return numeric_limits<size_type>::max(); }
+
+      template<typename _Alloc2>
+	struct __select_helper
+	{
+	  template<typename _Alloc3, typename
+	    = decltype(std::declval<_Alloc3*>()
+		->select_on_container_copy_construction())>
+	    static true_type __test(int);
+
+	  template<typename>
+	    static false_type __test(...);
+
+	  typedef decltype(__test<_Alloc2>(0)) type;
+	  static const bool value = type::value;
+	};
+      template<typename _Alloc2>
+	static typename
+       	enable_if<__select_helper<_Alloc2>::value, _Alloc2>::type
+       	_S_select(_Alloc2& __a)
+	{ return __a.select_on_container_copy_construction(); }
+
+      template<typename _Alloc2>
+	static typename
+       	enable_if<!__select_helper<_Alloc2>::value, _Alloc2>::type
+       	_S_select(_Alloc2& __a)
+	{ return __a; }
+
+    public:
+
+      /**
+       *  @brief  Allocate memory.
+       *  @param  a  An allocator.
+       *  @param  n  The number of objects to allocate space for.
+       *
+       *  Calls @c a.allocate(n)
+      */
+      static pointer
+      allocate(_Alloc& __a, size_type __n)
+      { return __a.allocate(__n); }
+
+      /**
+       *  @brief  Allocate memory.
+       *  @param  a  An allocator.
+       *  @param  n  The number of objects to allocate space for.
+       *  @param  hint Aid to locality.
+       *  @return Memory of suitable size and alignment for @a n objects
+       *          of type @c value_type
+       *
+       *  Returns <tt> a.allocate(n, hint) </tt> if that expression is
+       *  well-formed, otherwise returns @c a.allocate(n)
+      */
+      static pointer
+      allocate(_Alloc& __a, size_type __n, const_void_pointer __hint)
+      { return _S_allocate(__a, __n, __hint); }
+
+      /**
+       *  @brief  Deallocate memory.
+       *  @param  a  An allocator.
+       *  @param  p  Pointer to the memory to deallocate.
+       *  @param  n  The number of objects space was allocated for.
+       *
+       *  Calls <tt> a.deallocate(p, n) </tt>
+      */
+      static void deallocate(_Alloc& __a, pointer __p, size_type __n)
+      { __a.deallocate(__p, __n); }
+
+      /**
+       *  @brief  Construct an object of type @a Tp
+       *  @param  a  An allocator.
+       *  @param  p  Pointer to memory of suitable size and alignment for Tp
+       *  @param  args Constructor arguments.
+       *
+       *  Calls <tt> a.construct(p, std::forward<Args>(args)...) </tt>
+       *  if that expression is well-formed, otherwise uses placement-new
+       *  to construct an object of type @a Tp at location @a p from the
+       *  arguments @a args...
+      */
+      template<typename _Tp, typename... _Args>
+	static void construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
+	{ _S_construct(__a, __p, std::forward<_Args>(__args)...); }
+
+      /**
+       *  @brief  Destroy an object of type @a Tp
+       *  @param  a  An allocator.
+       *  @param  p  Pointer to the object to destroy
+       *
+       *  Calls @c a.destroy(p) if that expression is well-formed,
+       *  otherwise calls @c p->~Tp()
+      */
+      template <class _Tp>
+	static void destroy(_Alloc& __a, _Tp* __p)
+	{ _S_destroy(__a, __p); }
+
+      /**
+       *  @brief  The maximum supported allocation size
+       *  @param  a  An allocator.
+       *  @return @c a.max_size() or @c %numeric_limits<size_type>::max()
+       *
+       *  Returns @c a.max_size() if that expression is well-formed,
+       *  otherwise returns @c %numeric_limits<size_type>::max()
+      */
+      static size_type max_size(const _Alloc& __a)
+      { return _S_max_size(__a); }
+
+      /**
+       *  @brief  Obtain an allocator to use when copying a container.
+       *  @param  rhs  An allocator.
+       *  @return @c rhs.select_on_container_copy_construction() or @a rhs
+       *
+       *  Returns @c rhs.select_on_container_copy_construction() if that
+       *  expression is well-formed, otherwise returns @a rhs
+      */
+      static _Alloc
+      select_on_container_copy_construction(const _Alloc& __rhs)
+      { return _S_select(__rhs); }
+    };
+
 #endif
 
 _GLIBCXX_END_NAMESPACE_VERSION
Index: include/ext/array_allocator.h
===================================================================
--- include/ext/array_allocator.h	(revision 174358)
+++ include/ext/array_allocator.h	(working copy)
@@ -72,21 +72,25 @@
       max_size() const throw() 
       { return size_t(-1) / sizeof(_Tp); }
 
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+      template<typename _Up, typename... _Args>
+        void
+        construct(_Up* __p, _Args&&... __args)
+	{ ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
+
+      template<typename _Up>
+        void 
+        destroy(_Up* __p) { __p->~_Up(); }
+#else
       // _GLIBCXX_RESOLVE_LIB_DEFECTS
       // 402. wrong new expression in [some_] allocator::construct
       void 
       construct(pointer __p, const _Tp& __val) 
       { ::new((void *)__p) value_type(__val); }
 
-#ifdef __GXX_EXPERIMENTAL_CXX0X__
-      template<typename... _Args>
-        void
-        construct(pointer __p, _Args&&... __args)
-	{ ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
-#endif
-
       void 
       destroy(pointer __p) { __p->~_Tp(); }
+#endif
     };  
 
   /**
Index: include/ext/bitmap_allocator.h
===================================================================
--- include/ext/bitmap_allocator.h	(revision 174358)
+++ include/ext/bitmap_allocator.h	(working copy)
@@ -1053,20 +1053,25 @@
       max_size() const throw()
       { return size_type(-1) / sizeof(value_type); }
 
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+      template<typename _Up, typename... _Args>
+        void
+        construct(_Up* __p, _Args&&... __args)
+	{ ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
+
+      template<typename _Up>
+        void 
+        destroy(_Up* __p)
+        { __p->~_Up(); }
+#else
       void 
       construct(pointer __p, const_reference __data)
       { ::new((void *)__p) value_type(__data); }
 
-#ifdef __GXX_EXPERIMENTAL_CXX0X__
-      template<typename... _Args>
-        void
-        construct(pointer __p, _Args&&... __args)
-	{ ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
-#endif
-
       void 
       destroy(pointer __p)
       { __p->~value_type(); }
+#endif
     };
 
   template<typename _Tp1, typename _Tp2>
Index: include/ext/extptr_allocator.h
===================================================================
--- include/ext/extptr_allocator.h	(revision 174358)
+++ include/ext/extptr_allocator.h	(working copy)
@@ -100,18 +100,23 @@
       size_type max_size() const throw()
       { return std::numeric_limits<size_type>::max() / sizeof(_Tp); }
 
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+      template<typename _Up, typename... _Args>
+        void
+        construct(_Up* __p, _Args&&... __args)
+	{ ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
+
+      template<typename _Up>
+        void 
+        destroy(_Up* __p)
+        { __p->~_Up(); }
+#else
       void construct(pointer __p, const _Tp& __val)
       { ::new(__p.get()) _Tp(__val); }
 
-#ifdef __GXX_EXPERIMENTAL_CXX0X__
-      template<typename... _Args>
-        void
-        construct(pointer __p, _Args&&... __args)
-        { ::new(__p.get()) _Tp(std::forward<_Args>(__args)...); }
-#endif
-
       void destroy(pointer __p)
       { __p->~_Tp(); }
+#endif
 
       template<typename _Up>
         inline bool
Index: include/ext/malloc_allocator.h
===================================================================
--- include/ext/malloc_allocator.h	(revision 174358)
+++ include/ext/malloc_allocator.h	(working copy)
@@ -104,21 +104,25 @@
       max_size() const throw() 
       { return size_t(-1) / sizeof(_Tp); }
 
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+      template<typename _Up, typename... _Args>
+        void
+        construct(_Up* __p, _Args&&... __args)
+	{ ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
+
+      template<typename _Up>
+        void 
+        destroy(_Up* __p) { __p->~_Up(); }
+#else
       // _GLIBCXX_RESOLVE_LIB_DEFECTS
       // 402. wrong new expression in [some_] allocator::construct
       void 
       construct(pointer __p, const _Tp& __val) 
       { ::new((void *)__p) value_type(__val); }
 
-#ifdef __GXX_EXPERIMENTAL_CXX0X__
-      template<typename... _Args>
-        void
-        construct(pointer __p, _Args&&... __args) 
-	{ ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
-#endif
-
       void 
       destroy(pointer __p) { __p->~_Tp(); }
+#endif
     };
 
   template<typename _Tp>
Index: include/ext/mt_allocator.h
===================================================================
--- include/ext/mt_allocator.h	(revision 174358)
+++ include/ext/mt_allocator.h	(working copy)
@@ -588,21 +588,25 @@
       max_size() const throw() 
       { return size_t(-1) / sizeof(_Tp); }
 
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+      template<typename _Up, typename... _Args>
+        void
+        construct(_Up* __p, _Args&&... __args)
+	{ ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
+
+      template<typename _Up>
+        void 
+        destroy(_Up* __p) { __p->~_Up(); }
+#else
       // _GLIBCXX_RESOLVE_LIB_DEFECTS
       // 402. wrong new expression in [some_] allocator::construct
       void 
       construct(pointer __p, const _Tp& __val) 
       { ::new((void *)__p) _Tp(__val); }
 
-#ifdef __GXX_EXPERIMENTAL_CXX0X__
-      template<typename... _Args>
-        void
-        construct(pointer __p, _Args&&... __args)
-	{ ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
-#endif
-
       void 
       destroy(pointer __p) { __p->~_Tp(); }
+#endif
     };
 
 #ifdef __GTHREADS
Index: include/ext/new_allocator.h
===================================================================
--- include/ext/new_allocator.h	(revision 174358)
+++ include/ext/new_allocator.h	(working copy)
@@ -101,21 +101,25 @@
       max_size() const throw() 
       { return size_t(-1) / sizeof(_Tp); }
 
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+      template<typename _Up, typename... _Args>
+        void
+        construct(_Up* __p, _Args&&... __args)
+	{ ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
+
+      template<typename _Up>
+        void 
+        destroy(_Up* __p) { __p->~_Up(); }
+#else
       // _GLIBCXX_RESOLVE_LIB_DEFECTS
       // 402. wrong new expression in [some_] allocator::construct
       void 
       construct(pointer __p, const _Tp& __val) 
       { ::new((void *)__p) _Tp(__val); }
 
-#ifdef __GXX_EXPERIMENTAL_CXX0X__
-      template<typename... _Args>
-        void
-        construct(pointer __p, _Args&&... __args)
-	{ ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
-#endif
-
       void 
       destroy(pointer __p) { __p->~_Tp(); }
+#endif
     };
 
   template<typename _Tp>
Index: include/ext/pool_allocator.h
===================================================================
--- include/ext/pool_allocator.h	(revision 174358)
+++ include/ext/pool_allocator.h	(working copy)
@@ -158,21 +158,25 @@
       max_size() const throw() 
       { return size_t(-1) / sizeof(_Tp); }
 
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+      template<typename _Up, typename... _Args>
+        void
+        construct(_Up* __p, _Args&&... __args)
+	{ ::new((void *)__p) _Up(std::forward<_Args>(__args)...); }
+
+      template<typename _Up>
+        void 
+        destroy(_Up* __p) { __p->~_Up(); }
+#else
       // _GLIBCXX_RESOLVE_LIB_DEFECTS
       // 402. wrong new expression in [some_] allocator::construct
       void 
       construct(pointer __p, const _Tp& __val) 
       { ::new((void *)__p) _Tp(__val); }
 
-#ifdef __GXX_EXPERIMENTAL_CXX0X__
-      template<typename... _Args>
-        void
-        construct(pointer __p, _Args&&... __args)
-	{ ::new((void *)__p) _Tp(std::forward<_Args>(__args)...); }
-#endif
-
       void 
       destroy(pointer __p) { __p->~_Tp(); }
+#endif
 
       pointer
       allocate(size_type __n, const void* = 0);
Index: include/ext/throw_allocator.h
===================================================================
--- include/ext/throw_allocator.h	(revision 174358)
+++ include/ext/throw_allocator.h	(working copy)
@@ -639,20 +639,25 @@
 	return a;
       }
 
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+      template<typename _Up, typename... _Args>
+        void
+        construct(_Up* __p, _Args&&... __args)
+	{ return _M_allocator.construct(__p, std::forward<_Args>(__args)...); }
+
+      template<typename _Up>
+        void 
+        destroy(_Up* __p)
+        { _M_allocator.destroy(__p); }
+#else
       void
       construct(pointer __p, const value_type& val)
       { return _M_allocator.construct(__p, val); }
 
-#ifdef __GXX_EXPERIMENTAL_CXX0X__
-      template<typename... _Args>
-	void
-	construct(pointer __p, _Args&&... __args)
-	{ return _M_allocator.construct(__p, std::forward<_Args>(__args)...); }
-#endif
-
       void
       destroy(pointer __p)
       { _M_allocator.destroy(__p); }
+#endif
 
       void
       deallocate(pointer __p, size_type __n)
Index: testsuite/20_util/allocator_traits/requirements/typedefs.cc
===================================================================
--- testsuite/20_util/allocator_traits/requirements/typedefs.cc	(revision 0)
+++ testsuite/20_util/allocator_traits/requirements/typedefs.cc	(revision 0)
@@ -0,0 +1,52 @@
+// { dg-options "-std=gnu++0x" }
+//
+// Copyright (C) 2011 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/>.
+
+// 
+// NB: This file is for testing memory with NO OTHER INCLUDES.
+
+#include <memory>
+
+// { dg-do compile }
+
+template<typename T>
+void test01()
+{
+  // Check for required typedefs
+  typedef std::allocator_traits<T>                  test_type;
+  typedef typename test_type::pointer               pointer;
+  typedef typename test_type::const_pointer         const_pointer;
+  typedef typename test_type::void_pointer          void_pointer;
+  typedef typename test_type::const_void_pointer    const_void_pointer;
+  typedef typename test_type::difference_type       difference_type;
+  typedef typename test_type::size_type             size_type;
+  typedef typename test_type::propagate_on_container_copy_assignment
+    propagate_on_container_copy_assignment;
+  typedef typename test_type::propagate_on_container_move_assignment
+    propagate_on_container_move_assignment;
+  typedef typename test_type::propagate_on_container_swap
+    propagate_on_container_swap;
+}
+
+struct S { };
+
+int main()
+{
+  test01<std::allocator<int>>();
+  test01<std::allocator<S>>();
+}
Index: testsuite/20_util/allocator_traits/requirements/explicit_instantiation.cc
===================================================================
--- testsuite/20_util/allocator_traits/requirements/explicit_instantiation.cc	(revision 0)
+++ testsuite/20_util/allocator_traits/requirements/explicit_instantiation.cc	(revision 0)
@@ -0,0 +1,29 @@
+// { dg-options "-std=gnu++0x" }
+// { dg-do compile }
+
+// Copyright (C) 2011 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/>.
+
+// NB: This file is for testing memory with NO OTHER INCLUDES.
+
+#include <memory>
+
+namespace std
+{
+  typedef short test_type;
+  template struct allocator_traits<std::allocator<test_type>>;
+}
Index: testsuite/20_util/allocator_traits/members/max_size.cc
===================================================================
--- testsuite/20_util/allocator_traits/members/max_size.cc	(revision 0)
+++ testsuite/20_util/allocator_traits/members/max_size.cc	(revision 0)
@@ -0,0 +1,67 @@
+// { dg-options "-std=gnu++0x" }
+
+// Copyright (C) 2011 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/>.
+
+#include <memory>
+#include <limits>
+#include <type_traits>
+#include <testsuite_hooks.h>
+
+struct X { };
+
+template<typename T>
+struct maxsize_allocator
+{
+  typedef T value_type;
+  typedef unsigned size_type;
+
+  size_type max_size() const { return 100; }
+};
+
+template<typename T>
+struct unsized_allocator
+{
+  typedef T value_type;
+};
+
+
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+
+  typedef std::allocator_traits<maxsize_allocator<X>> traits_type;
+  traits_type::allocator_type a;
+  auto size = a.max_size();
+  VERIFY( traits_type::max_size(a) == size );
+}
+
+void test02()
+{
+  bool test __attribute__((unused)) = true;
+
+  typedef std::allocator_traits<unsized_allocator<X>> traits_type;
+  traits_type::allocator_type a;
+  auto size = std::numeric_limits<traits_type::size_type>::max();
+  VERIFY( traits_type::max_size(a) == size );
+}
+
+int main()
+{
+  test01();
+  test02();
+}
Index: testsuite/20_util/allocator_traits/members/select.cc
===================================================================
--- testsuite/20_util/allocator_traits/members/select.cc	(revision 0)
+++ testsuite/20_util/allocator_traits/members/select.cc	(revision 0)
@@ -0,0 +1,68 @@
+// { dg-options "-std=gnu++0x" }
+// { dg-do compile }
+
+// Copyright (C) 2011 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/>.
+
+#include <memory>
+#include <testsuite_hooks.h>
+
+struct X { };
+
+template<typename T>
+struct alloc1
+{
+  typedef T value_type;
+
+  int id;
+};
+
+template<typename T>
+struct alloc2
+{
+  typedef T value_type;
+
+  int id;
+
+  alloc2 select_on_container_copy_construction() const
+  { return alloc2{id+1}; }
+};
+
+
+void test01()
+{
+  typedef std::allocator_traits<alloc1<X>> traits_type;
+  traits_type::allocator_type a{1};
+  const traits_type::allocator_type& a2
+    = traits_type::select_on_container_copy_construction(a);
+  VERIFY( a2.id == a.id );
+}
+
+void test02()
+{
+  typedef std::allocator_traits<alloc1<X>> traits_type;
+  traits_type::allocator_type a{1};
+  const traits_type::allocator_type& a2
+    = traits_type::select_on_container_copy_construction(a);
+  VERIFY( a2.id != a.id );
+}
+
+int main()
+{
+  test01();
+  test02();
+}
Index: testsuite/20_util/allocator_traits/members/construct.cc
===================================================================
--- testsuite/20_util/allocator_traits/members/construct.cc	(revision 0)
+++ testsuite/20_util/allocator_traits/members/construct.cc	(revision 0)
@@ -0,0 +1,79 @@
+// { dg-options "-std=gnu++0x" }
+
+// Copyright (C) 2011 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/>.
+
+#include <memory>
+#include <cstddef>
+#include <testsuite_hooks.h>
+
+struct X
+{
+  static int counter;
+  X() { }
+  X(const X&) { ++counter; }
+  explicit X(int) { ++counter; }
+  X(int, int) { ++counter; }
+  X(int, int, int) { ++counter; }
+};
+
+int X::counter = 0;
+
+template<typename T>
+struct fake_allocator
+{
+  typedef T value_type;
+
+  fake_allocator() : counter() {}
+
+  int counter;
+
+  T* allocate(std::size_t n) { return (T*)new char[n*sizeof(T)]; }
+  void deallocate(T* p, std::size_t) { delete[] (char*)p; }
+
+  // don't actually construct anything when these are called
+  void construct(T* p) { ++counter; }
+  void construct(T* p, int, int) { ++counter; }
+};
+
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+
+  typedef std::allocator_traits<fake_allocator<X>> traits_type;
+  traits_type::allocator_type a;
+  X* p = traits_type::allocate(a, 1);
+  traits_type::construct(a, p);
+  VERIFY( a.counter == 1 );
+  traits_type::construct(a, p, 1);
+  VERIFY( a.counter == 1 );
+  VERIFY( X::counter == 1 );
+  traits_type::destroy(a, p);
+  traits_type::construct(a, p, 1, 1);
+  VERIFY( a.counter == 2 );
+  VERIFY( X::counter == 1 );
+  traits_type::construct(a, p, 1, 1, 1);
+  VERIFY( a.counter == 2 );
+  VERIFY( X::counter == 2 );
+  traits_type::destroy(a, p);
+  traits_type::deallocate(a, p, 1);
+}
+
+int main()
+{
+  test01();
+}
Index: testsuite/20_util/allocator_traits/members/allocate_hint.cc
===================================================================
--- testsuite/20_util/allocator_traits/members/allocate_hint.cc	(revision 0)
+++ testsuite/20_util/allocator_traits/members/allocate_hint.cc	(revision 0)
@@ -0,0 +1,90 @@
+// { dg-options "-std=gnu++0x" }
+
+// Copyright (C) 2011 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/>.
+
+#include <memory>
+#include <cstddef>
+#include <testsuite_hooks.h>
+
+struct X { };
+
+template<typename T>
+struct hintable_allocator
+{
+  typedef T value_type;
+  struct const_void_pointer { };
+  typedef unsigned size_type;
+
+  hintable_allocator() : called(false) { }
+
+  bool called;
+
+  // this is the overload that should get called:
+  T* allocate(size_type n, const_void_pointer) { called = true; return 0; }
+
+  // none of these should get called:
+  T* allocate(size_type n);
+  T* allocate(size_type n, void*);
+  T* allocate(size_type n, const void*);
+  T* allocate(size_type n, const_void_pointer) const;
+};
+
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+
+  typedef std::allocator_traits<hintable_allocator<X>> traits_type;
+  traits_type::allocator_type a;
+  traits_type::const_void_pointer v;
+  X* p = traits_type::allocate(a, 1, v);
+  VERIFY( a.called );
+}
+
+template<typename T>
+struct unhintable_allocator
+{
+  typedef T value_type;
+  typedef unsigned size_type;
+
+  unhintable_allocator() : called(false) { }
+
+  bool called;
+
+  // this is the overload that should get called:
+  T* allocate(size_type n) { called = true; return 0; }
+
+  // this should not get called:
+  T* allocate(size_type n, void*);
+};
+
+void test02()
+{
+  bool test __attribute__((unused)) = true;
+
+  typedef std::allocator_traits<unhintable_allocator<X>> traits_type;
+  traits_type::allocator_type a;
+  traits_type::const_void_pointer v;
+  X* p = traits_type::allocate(a, 1, v);
+  VERIFY( a.called );
+}
+
+int main()
+{
+  test01();
+  test02();
+}
Index: testsuite/20_util/allocator_traits/members/destroy.cc
===================================================================
--- testsuite/20_util/allocator_traits/members/destroy.cc	(revision 0)
+++ testsuite/20_util/allocator_traits/members/destroy.cc	(revision 0)
@@ -0,0 +1,84 @@
+// { dg-options "-std=gnu++0x" }
+// { dg-do compile }
+
+// Copyright (C) 2011 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/>.
+
+#include <memory>
+#include <new>
+#include <testsuite_hooks.h>
+
+struct X
+{
+  static int counter;
+  ~X() { ++counter; }
+};
+
+int X::counter = 0;
+
+template<typename T>
+struct allocator_with_destroy
+{
+  typedef T value_type;
+
+  allocator_with_destroy() : called() { }
+
+  void destroy(T* p) { called = true; }
+
+  int called;
+};
+
+template<typename T>
+struct allocator_without_destroy
+{
+  typedef T value_type;
+
+  allocator_without_destroy() : called() { }
+
+  int called;
+};
+
+void test01()
+{
+  bool test __attribute__((unused)) = true;
+
+  typedef std::allocator_traits<allocator_with_destroy<X>> traits_type;
+  traits_type::allocator_type a;
+  X* p = 0;
+  traits_type::destroy(a, p);
+  VERIFY( a.called );
+  VERIFY( X::counter == 0 );
+}
+
+void test02()
+{
+  bool test __attribute__((unused)) = true;
+
+  typedef std::allocator_traits<allocator_without_destroy<X>> traits_type;
+  traits_type::allocator_type a;
+  char buf[sizeof(X)];
+  X* p = ::new (static_cast<void*>(buf)) X();
+  traits_type::destroy(a, p);
+  VERIFY( !a.called );
+  VERIFY( X::counter == 1 );
+}
+
+int main()
+{
+  test01();
+  test02();
+}
Index: testsuite/20_util/pointer_traits/requirements/typedefs.cc
===================================================================
--- testsuite/20_util/pointer_traits/requirements/typedefs.cc	(revision 0)
+++ testsuite/20_util/pointer_traits/requirements/typedefs.cc	(revision 0)
@@ -0,0 +1,45 @@
+// { dg-options "-std=gnu++0x" }
+//
+// Copyright (C) 2011 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/>.
+
+// 
+// NB: This file is for testing memory with NO OTHER INCLUDES.
+
+#include <memory>
+
+// { dg-do compile }
+
+template<typename Ptr>
+void test01()
+{
+  // Check for required typedefs
+  typedef std::pointer_traits<Ptr>              test_type;
+  typedef typename test_type::pointer           pointer;
+  typedef typename test_type::element_type      element_type;
+  typedef typename test_type::difference_type   difference_type;
+}
+
+int main()
+{
+  test01<int*>();
+  test01<void*>();
+  test01<std::shared_ptr<int>>();
+  test01<std::shared_ptr<void>>();
+  test01<std::unique_ptr<int>>();
+  test01<std::unique_ptr<void>>();
+}
Index: testsuite/20_util/pointer_traits/requirements/explicit_instantiation.cc
===================================================================
--- testsuite/20_util/pointer_traits/requirements/explicit_instantiation.cc	(revision 0)
+++ testsuite/20_util/pointer_traits/requirements/explicit_instantiation.cc	(revision 0)
@@ -0,0 +1,31 @@
+// { dg-options "-std=gnu++0x" }
+// { dg-do compile }
+
+// Copyright (C) 2011 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/>.
+
+// NB: This file is for testing memory with NO OTHER INCLUDES.
+
+#include <memory>
+
+namespace std
+{
+  typedef short test_type;
+  template struct pointer_traits<test_type*>;
+  template struct pointer_traits<shared_ptr<test_type>>;
+  template struct pointer_traits<unique_ptr<test_type>>;
+}

Re: [v3] Implement pointer_traits and allocator_traits

[Jonathan Wakely]

I forgot to mention this is missing the rebind templates, which depend
on alias template support in G++

Re: [v3] Implement pointer_traits and allocator_traits

[Jonathan Wakely]

[-- Attachment #1: Type: text/plain, Size: 1895 bytes --]

Here's a patch to make shared_ptr use allocator_traits, I don't plan
to commit this (at least not yet) but it shows what's needed to use
allocator_traits instead of the C++03 way of doing things.  It uses
allocator_traits<T>::__rebind<U>::__type which is a temporary
substitute for the unsupported allocator_traits<T>::rebind<U> template
alias.

This patch isn't quite backward compatible, because I changed
_Sp_counted_deleter::_My_deleter to derive from the supplied _Alloc
type instead of the rebound type.  I think that's more correct, but
changes the type (and possibly size) of the _M_del member.  The safe
way to make that change is probably to rename _Sp_counted_deleter to
_Sp_counted_deleter2, so that code built against the old header uses
the old type and code built with the new header uses a new, distinct
type.

I completely rewrote _Sp_counted_ptr_inplace because it doesn't need a
deleter, so doesn't need to derive from _Sp_counted_deleter and can
benefit from the EBO. That could be renamed _Sp_counted_ptr_inplace2
for compatibility.

Apart from demonstrating how to make use of allocator_traits to
support both C++03 and C++11 allocators, this patch allows the
following example to work, using allocate_shared to create a
shared_ptr to a type with no public constructors or destructor, by
using a custom allocator which is declared as a friend:

#include <memory>
#include <new>

template<typename T>
struct MyAlloc;

class Private
{
  Private() = default;
  Private(const Private&) = default;
  ~Private() = default;

  friend class MyAlloc<Private>;

public:
  int get() const { return 0; }
};

template<typename T>
struct MyAlloc : std::allocator<Private>
{
  void construct(void* p) { ::new(p) Private(); }
};

int main()
{
  MyAlloc<Private> a;
  auto p = std::allocate_shared<Private>(a);
  return p->get();
}

This allows you to write types which can only be managed

[-- Attachment #2: sp-alloc.txt --]
[-- Type: text/plain, Size: 7490 bytes --]

Index: include/bits/shared_ptr_base.h
===================================================================
--- include/bits/shared_ptr_base.h	(revision 174358)
+++ include/bits/shared_ptr_base.h	(working copy)
@@ -323,18 +323,15 @@
   template<typename _Ptr, typename _Deleter, typename _Alloc, _Lock_policy _Lp>
     class _Sp_counted_deleter : public _Sp_counted_base<_Lp>
     {
-      typedef typename _Alloc::template
-	  rebind<_Sp_counted_deleter>::other _My_alloc_type;
-
       // Helper class that stores the Deleter and also acts as an allocator.
       // Used to dispose of the owned pointer and the internal refcount
       // Requires that copies of _Alloc can free each other's memory.
       struct _My_Deleter
-      : public _My_alloc_type    // copy constructor must not throw
+      : public _Alloc           // copy constructor must not throw
       {
-	_Deleter _M_del;         // copy constructor must not throw
+	_Deleter _M_del;        // copy constructor must not throw
 	_My_Deleter(_Deleter __d, const _Alloc& __a)
-	: _My_alloc_type(__a), _M_del(__d) { }
+	: _Alloc(__a), _M_del(__d) { }
       };
 
     public:
@@ -353,9 +350,11 @@
       virtual void
       _M_destroy() noexcept
       {
-	_My_alloc_type __a(_M_del);
-	this->~_Sp_counted_deleter();
-	__a.deallocate(this, 1);
+	typedef typename allocator_traits<_Alloc>::template
+	  __rebind_traits<_Sp_counted_deleter>::__type _My_alloc_traits;
+	typename _My_alloc_traits::allocator_type __a(_M_del);
+	_My_alloc_traits::destroy(__a, this);
+	_My_alloc_traits::deallocate(__a, this, 1);
       }
 
       virtual void*
@@ -375,51 +374,44 @@
 
   // helpers for make_shared / allocate_shared
 
-  template<typename _Tp>
-    struct _Sp_destroy_inplace
-    {
-      void operator()(_Tp* __p) const { if (__p) __p->~_Tp(); }
-    };
-
   struct _Sp_make_shared_tag { };
 
   template<typename _Tp, typename _Alloc, _Lock_policy _Lp>
-    class _Sp_counted_ptr_inplace
-    : public _Sp_counted_deleter<_Tp*, _Sp_destroy_inplace<_Tp>, _Alloc, _Lp>
+    class _Sp_counted_ptr_inplace : public _Sp_counted_base<_Lp>
     {
-      typedef _Sp_counted_deleter<_Tp*, _Sp_destroy_inplace<_Tp>, _Alloc, _Lp>
-	_Base_type;
+      // Helper class that stores the pointer and also acts as an allocator.
+      // Used to dispose of the owned pointer and the internal refcount
+      // Requires that copies of _Alloc can free each other's memory.
+      struct _Impl
+      : public _Alloc           // copy constructor must not throw
+      {
+	_Impl(_Alloc __a) : _Alloc(__a), _M_ptr() { }
+	_Tp* _M_ptr;
+      };
 
     public:
-      explicit
-      _Sp_counted_ptr_inplace(_Alloc __a)
-      : _Base_type(static_cast<_Tp*>(0), _Sp_destroy_inplace<_Tp>(), __a)
-      , _M_storage()
-      {
-	void* __p = &_M_storage;
-	::new (__p) _Tp();  // might throw
-	_Base_type::_M_ptr = static_cast<_Tp*>(__p);
-      }
-
       template<typename... _Args>
 	_Sp_counted_ptr_inplace(_Alloc __a, _Args&&... __args)
-	: _Base_type(static_cast<_Tp*>(0), _Sp_destroy_inplace<_Tp>(), __a)
-	, _M_storage()
+	: _M_impl(__a), _M_storage()
 	{
-	  void* __p = &_M_storage;
-	  ::new (__p) _Tp(std::forward<_Args>(__args)...);  // might throw
-	  _Base_type::_M_ptr = static_cast<_Tp*>(__p);
+	  _M_impl._M_ptr = static_cast<_Tp*>(static_cast<void*>(&_M_storage));
+	  allocator_traits<_Alloc>::construct(__a, _M_impl._M_ptr,
+	      std::forward<_Args>(__args)...); // might throw
 	}
 
+      virtual void
+      _M_dispose() noexcept
+      { allocator_traits<_Alloc>::destroy(_M_impl, _M_impl._M_ptr); }
+
       // Override because the allocator needs to know the dynamic type
       virtual void
       _M_destroy() noexcept
       {
-	typedef typename _Alloc::template
-	    rebind<_Sp_counted_ptr_inplace>::other _My_alloc_type;
-	_My_alloc_type __a(_Base_type::_M_del);
-	this->~_Sp_counted_ptr_inplace();
-	__a.deallocate(this, 1);
+	typedef typename allocator_traits<_Alloc>::template
+	  __rebind_traits<_Sp_counted_ptr_inplace>::__type _My_alloc_traits;
+	typename _My_alloc_traits::allocator_type __a(_M_impl);
+	_My_alloc_traits::destroy(__a, this);
+	_My_alloc_traits::deallocate(__a, this, 1);
       }
 
       // Sneaky trick so __shared_ptr can get the managed pointer
@@ -429,13 +421,14 @@
 #ifdef __GXX_RTTI
 	return __ti == typeid(_Sp_make_shared_tag)
 	       ? static_cast<void*>(&_M_storage)
-	       : _Base_type::_M_get_deleter(__ti);
+	       : 0;
 #else
         return 0;
 #endif
       }
 
     private:
+      _Impl _M_impl;
       typename aligned_storage<sizeof(_Tp), alignment_of<_Tp>::value>::type
 	_M_storage;
     };
@@ -468,18 +461,21 @@
 	  // The allocator's value_type doesn't matter, will rebind it anyway.
 	  typedef std::allocator<int> _Alloc;
 	  typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type;
-	  typedef std::allocator<_Sp_cd_type> _Alloc2;
-	  _Alloc2 __a2;
+	  typedef typename allocator_traits<_Alloc> ::template
+	    __rebind_traits<_Sp_cd_type>::__type _Alloc_traits;
+	  typename _Alloc_traits::allocator_type __a;
+	  _Sp_cd_type* __mem = 0;
 	  __try
 	    {
-	      _M_pi = __a2.allocate(1);
-	      ::new(static_cast<void*>(_M_pi)) _Sp_cd_type(__p, __d);
+	      __mem = _Alloc_traits::allocate(__a, 1);
+	      _Alloc_traits::construct(__a, __mem, __p, std::move(__d));
+	      _M_pi = __mem;
 	    }
 	  __catch(...)
 	    {
 	      __d(__p); // Call _Deleter on __p.
-	      if (_M_pi)
-		__a2.deallocate(static_cast<_Sp_cd_type*>(_M_pi), 1);
+	      if (__mem)
+	        _Alloc_traits::deallocate(__a, __mem, 1);
 	      __throw_exception_again;
 	    }
 	}
@@ -488,18 +484,22 @@
 	__shared_count(_Ptr __p, _Deleter __d, _Alloc __a) : _M_pi(0)
 	{
 	  typedef _Sp_counted_deleter<_Ptr, _Deleter, _Alloc, _Lp> _Sp_cd_type;
-	  typedef typename _Alloc::template rebind<_Sp_cd_type>::other _Alloc2;
-	  _Alloc2 __a2(__a);
+	  typedef typename allocator_traits<_Alloc> ::template
+	    __rebind_traits<_Sp_cd_type>::__type _Alloc_traits;
+	  typename _Alloc_traits::allocator_type __a2(__a);
+	  _Sp_cd_type* __mem = 0;
 	  __try
 	    {
-	      _M_pi = __a2.allocate(1);
-	      ::new(static_cast<void*>(_M_pi)) _Sp_cd_type(__p, __d, __a);
+	      __mem = _Alloc_traits::allocate(__a2, 1);
+	      _Alloc_traits::construct(__a2, __mem,
+		  __p, std::move(__d), std::move(__a));
+	      _M_pi = __mem;
 	    }
 	  __catch(...)
 	    {
 	      __d(__p); // Call _Deleter on __p.
-	      if (_M_pi)
-		__a2.deallocate(static_cast<_Sp_cd_type*>(_M_pi), 1);
+	      if (__mem)
+	        _Alloc_traits::deallocate(__a2, __mem, 1);
 	      __throw_exception_again;
 	    }
 	}
@@ -510,18 +510,19 @@
 	: _M_pi(0)
 	{
 	  typedef _Sp_counted_ptr_inplace<_Tp, _Alloc, _Lp> _Sp_cp_type;
-	  typedef typename _Alloc::template rebind<_Sp_cp_type>::other _Alloc2;
-	  _Alloc2 __a2(__a);
+	  typedef typename allocator_traits<_Alloc> ::template
+	    __rebind_traits<_Sp_cp_type>::__type _Alloc_traits;
+	  typename _Alloc_traits::allocator_type __a2(__a);
+	  _Sp_cp_type* __mem = _Alloc_traits::allocate(__a2, 1);
 	  __try
 	    {
-	      _M_pi = __a2.allocate(1);
-	      ::new(static_cast<void*>(_M_pi)) _Sp_cp_type(__a,
+	      _Alloc_traits::construct(__a2, __mem, std::move(__a),
 		    std::forward<_Args>(__args)...);
+	      _M_pi = __mem;
 	    }
 	  __catch(...)
 	    {
-	      if (_M_pi)
-		__a2.deallocate(static_cast<_Sp_cp_type*>(_M_pi), 1);
+	      _Alloc_traits::deallocate(__a2, __mem, 1);
 	      __throw_exception_again;
 	    }
 	}

Re: [v3] Implement pointer_traits and allocator_traits

[Jonathan Wakely]

On 28 May 2011 15:53, Jonathan Wakely wrote:
>
> This allows you to write types which can only be managed

... by shared_ptr and can't be created/copied/destroyed any other way.

Re: [v3] Implement pointer_traits and allocator_traits

[Jonathan Wakely]

[-- Attachment #1: Type: text/plain, Size: 174 bytes --]

One more test

2011-05-28  Jonathan Wakely  <jwakely.gcc@gmail.com>

        * testsuite/20_util/pointer_traits/pointer_to.cc: New.

Tested x86_64-linux, committed to trunk.

[-- Attachment #2: pointer_to.txt --]
[-- Type: text/plain, Size: 1514 bytes --]

Index: testsuite/20_util/pointer_traits/pointer_to.cc
===================================================================
--- testsuite/20_util/pointer_traits/pointer_to.cc	(revision 0)
+++ testsuite/20_util/pointer_traits/pointer_to.cc	(revision 0)
@@ -0,0 +1,50 @@
+// { dg-options "-std=gnu++0x" }
+
+// Copyright (C) 2011 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/>.
+
+
+#include <memory>
+#include <testsuite_hooks.h>
+
+struct Ptr
+{
+  typedef bool element_type;
+
+  static bool* pointer_to(bool& b) { return 0; }
+};
+
+void test01()
+{
+  bool test = true;
+
+  VERIFY( std::pointer_traits<Ptr>::pointer_to(test) == 0 );
+}
+
+void test02()
+{
+  bool test = true;
+
+  VERIFY( std::pointer_traits<bool*>::pointer_to(test) == &test );
+}
+
+int main()
+{
+  test01();
+  test02();
+  return 0;
+}

Re: [v3] Implement pointer_traits and allocator_traits

[Jonathan Wakely]

On 28 May 2011 18:14, Jonathan Wakely wrote:
> One more test
>
> 2011-05-28  Jonathan Wakely  <jwakely.gcc@gmail.com>
>
>        * testsuite/20_util/pointer_traits/pointer_to.cc: New.
>
> Tested x86_64-linux, committed to trunk.
>

This new test is failing, I'm looking into why, will revert it if necessary ...

Re: [v3] Implement pointer_traits and allocator_traits

[Jonathan Wakely]

[-- Attachment #1: Type: text/plain, Size: 727 bytes --]

On 28 May 2011 20:08, Jonathan Wakely wrote:
> On 28 May 2011 18:14, Jonathan Wakely wrote:
>> One more test
>>
>> 2011-05-28  Jonathan Wakely  <jwakely.gcc@gmail.com>
>>
>>        * testsuite/20_util/pointer_traits/pointer_to.cc: New.
>>
>> Tested x86_64-linux, committed to trunk.
>>
>
> This new test is failing, I'm looking into why, will revert it if necessary ...
>

2011-05-28  Jonathan Wakely  <jwakely.gcc@gmail.com>

        * testsuite/20_util/pointer_traits/pointer_to.cc: Fix.

I added the pointer_traits<Ptr> case at the last minute and it was
broken, not sure how I didn't notice - I must have tested in the wrong
directory.  This fixes it, definitely tested this time, sorry for the
mess!

[-- Attachment #2: fix.txt --]
[-- Type: text/plain, Size: 662 bytes --]

Index: testsuite/20_util/pointer_traits/pointer_to.cc
===================================================================
--- testsuite/20_util/pointer_traits/pointer_to.cc	(revision 174381)
+++ testsuite/20_util/pointer_traits/pointer_to.cc	(working copy)
@@ -24,15 +24,17 @@
 struct Ptr
 {
   typedef bool element_type;
+  bool* value;
 
-  static bool* pointer_to(bool& b) { return 0; }
+  static Ptr pointer_to(bool& b) { return Ptr{&b}; }
 };
 
 void test01()
 {
   bool test = true;
+  Ptr p{&test};
 
-  VERIFY( std::pointer_traits<Ptr>::pointer_to(test) == 0 );
+  VERIFY( std::pointer_traits<Ptr>::pointer_to(test).value == &test );
 }
 
 void test02()