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[patch] Fix bug in experimental::any


This fixes the uses-allocator construction in experimental::any and
re-orders the data members so that I can extract the stored value in a
Python printer without having to walk the inheritance hierarchy of a
std::tuple.

The actual pretty printer for any (and string_view and optional) will
follow Real Soon Now.

Tested x86_64-linux, committed to trunk.

commit a5b7242e6eed8f4bbac02ddfb9c798d55481e264
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu Jul 10 15:22:35 2014 +0100

    	* include/experimental/any (any::_Manager_alloc::_Data): Reorder
    	tuple members to simplify pretty printing.
    	(any::_Manager_alloc::_Data::_M_construct): Fix uses-allocator
    	construction.
    	* testsuite/experimental/any/cons/4.cc: New.

diff --git a/libstdc++-v3/include/experimental/any b/libstdc++-v3/include/experimental/any
index a69d006..a4ac983 100644
--- a/libstdc++-v3/include/experimental/any
+++ b/libstdc++-v3/include/experimental/any
@@ -450,18 +450,18 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     {
       using _Traits = std::allocator_traits<_Alloc>;
 
-      std::tuple<_Alloc, __gnu_cxx::__aligned_buffer<_Tp>> _M_data;
+      std::tuple<__gnu_cxx::__aligned_buffer<_Tp>, _Alloc> _M_data;
 
-      _Alloc&       _M_alloc()       { return std::get<0>(_M_data); }
-      const _Alloc& _M_alloc() const { return std::get<0>(_M_data); }
+      _Alloc&       _M_alloc()       { return std::get<1>(_M_data); }
+      const _Alloc& _M_alloc() const { return std::get<1>(_M_data); }
 
-      _Tp*       _M_obj()       { return std::get<1>(_M_data)._M_ptr(); }
-      const _Tp* _M_obj() const { return std::get<1>(_M_data)._M_ptr(); }
+      _Tp*       _M_obj()       { return std::get<0>(_M_data)._M_ptr(); }
+      const _Tp* _M_obj() const { return std::get<0>(_M_data)._M_ptr(); }
 
       template<typename _Up>
-	_Data(const _Alloc& __a, _Up&& __val) : _M_data(__a, nullptr)
+	_Data(const _Alloc& __a, _Up&& __val) : _M_data(nullptr, __a)
 	{
-	  this->_M_construct(std::__use_alloc<_Tp>(_M_alloc()),
+	  this->_M_construct(std::__use_alloc<_Tp, _Alloc, _Up&&>(_M_alloc()),
 			     std::forward<_Up>(__val));
 	}
 
@@ -479,8 +479,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	void
 	_M_construct(__uses_alloc1<_Alloc> __a, _Up&& __val)
 	{
-	  _Traits::construct(__a._M_a, _M_obj(),
-			     std::allocator_arg, __a._M_a,
+	  _Traits::construct(_M_alloc(), _M_obj(),
+			     std::allocator_arg, *__a._M_a,
 			     std::forward<_Up>(__val));
 	}
 
@@ -488,8 +488,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	void
 	_M_construct(__uses_alloc2<_Alloc> __a, _Up&& __val)
 	{
-	  _Traits::construct(__a._M_a, _M_obj(),
-			     std::forward<_Up>(__val), __a._M_a);
+	  _Traits::construct(_M_alloc(), _M_obj(),
+			     std::forward<_Up>(__val), *__a._M_a);
 	}
     };
 
diff --git a/libstdc++-v3/testsuite/experimental/any/cons/4.cc b/libstdc++-v3/testsuite/experimental/any/cons/4.cc
new file mode 100644
index 0000000..6e5e019
--- /dev/null
+++ b/libstdc++-v3/testsuite/experimental/any/cons/4.cc
@@ -0,0 +1,73 @@
+// { dg-options "-std=gnu++14" }
+// { dg-do run }
+
+// 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/>.
+
+#include <experimental/any>
+#include <memory>
+#include <testsuite_hooks.h>
+
+using std::experimental::any;
+
+struct NotSmall
+{
+  char c[64];  // prevent small-object optimization
+};
+
+struct T1
+{
+  using allocator_type = std::allocator<char>;
+
+  T1() = default;
+  T1(const T1&) : used_alloc(false) { }
+  T1(const T1&, const allocator_type&) : used_alloc(true) { }
+
+  bool used_alloc;
+
+  NotSmall x;
+};
+
+struct T2
+{
+  using allocator_type = std::allocator<char>;
+
+  T2() = default;
+  T2(const T2&) : used_alloc(false) { }
+  T2(std::allocator_arg_t, const allocator_type&, const T2&) : used_alloc(true)
+  { }
+
+  bool used_alloc;
+
+  NotSmall x;
+};
+
+bool test [[gnu::unused]] = true;
+
+void test01()
+{
+  any x1(std::allocator_arg, std::allocator<char>{}, T1{});
+  VERIFY( std::experimental::any_cast<T1&>(x1).used_alloc );
+
+  any x2(std::allocator_arg, std::allocator<char>{}, T2{});
+  VERIFY( std::experimental::any_cast<T2&>(x2).used_alloc );
+}
+
+int main()
+{
+  test01();
+}

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