[patch] libstdc++/63840 fix exception-safety in std::function copy constructor

[Jonathan Wakely <jwakely at redhat dot com>]

Because the fix is so simple I'm doing it for std::tr1::function as
well. I intend to backport this to 4.8 and 4.9 too.

Tested x86_64-linux + powerpc64-linux, committed to trunk.

commit 96d883f68114f32aeb38fd4d456b61d34ddee48d
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Nov 14 17:09:21 2014 +0000

    	PR libstdc++/63840
    	* include/std/functional (function::function(const function&)): Set
    	_M_manager after operations that might throw.
    	* include/tr1/functional (function::function(const function&),
    	function::function(_Functor, _Useless)): Likewise.
    	* testsuite/20_util/function/63840.cc: New.
    	* testsuite/tr1/3_function_objects/function/63840.cc: New.

diff --git a/libstdc++-v3/include/std/functional b/libstdc++-v3/include/std/functional
index 71d97ad..158dfa1 100644
--- a/libstdc++-v3/include/std/functional
+++ b/libstdc++-v3/include/std/functional
@@ -2239,9 +2239,9 @@ _GLIBCXX_MEM_FN_TRAITS(&&, false_type, true_type)
     {
       if (static_cast<bool>(__x))
 	{
+	  __x._M_manager(_M_functor, __x._M_functor, __clone_functor);
 	  _M_invoker = __x._M_invoker;
 	  _M_manager = __x._M_manager;
-	  __x._M_manager(_M_functor, __x._M_functor, __clone_functor);
 	}
     }
 
diff --git a/libstdc++-v3/include/tr1/functional b/libstdc++-v3/include/tr1/functional
index 20785ff..58af910 100644
--- a/libstdc++-v3/include/tr1/functional
+++ b/libstdc++-v3/include/tr1/functional
@@ -2112,9 +2112,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     {
       if (static_cast<bool>(__x))
 	{
+	  __x._M_manager(_M_functor, __x._M_functor, __clone_functor);
 	  _M_invoker = __x._M_invoker;
 	  _M_manager = __x._M_manager;
-	  __x._M_manager(_M_functor, __x._M_functor, __clone_functor);
 	}
     }
 
@@ -2130,9 +2130,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
 	if (_My_handler::_M_not_empty_function(__f))
 	  {
+	    _My_handler::_M_init_functor(_M_functor, __f);
 	    _M_invoker = &_My_handler::_M_invoke;
 	    _M_manager = &_My_handler::_M_manager;
-	    _My_handler::_M_init_functor(_M_functor, __f);
 	  }
       }
 
diff --git a/libstdc++-v3/testsuite/20_util/function/63840.cc b/libstdc++-v3/testsuite/20_util/function/63840.cc
new file mode 100644
index 0000000..cf80aa1
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/function/63840.cc
@@ -0,0 +1,55 @@
+// 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/>.
+
+// { dg-options "-std=gnu++11" }
+
+#include <functional>
+#include <stdexcept>
+#include <testsuite_hooks.h>
+
+struct functor
+{
+  functor() = default;
+
+  functor(const functor&)
+  {
+    throw std::runtime_error("test");
+  }
+
+  functor(functor&& f) = default;
+
+  void operator()() const { }
+};
+
+
+void
+test01()
+{
+  std::function<void()> f = functor{};
+  try {
+    auto g = f;
+  } catch (const std::runtime_error& e) {
+    return;
+  }
+  VERIFY(false);
+}
+
+int
+main()
+{
+  test01();
+}
diff --git a/libstdc++-v3/testsuite/tr1/3_function_objects/function/63840.cc b/libstdc++-v3/testsuite/tr1/3_function_objects/function/63840.cc
new file mode 100644
index 0000000..760d490
--- /dev/null
+++ b/libstdc++-v3/testsuite/tr1/3_function_objects/function/63840.cc
@@ -0,0 +1,55 @@
+// 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 <tr1/functional>
+#include <stdexcept>
+#include <testsuite_hooks.h>
+
+struct functor
+{
+  functor() : copies(0) { }
+
+  functor(const functor& f)
+  : copies(f.copies + 1)
+  {
+    if (copies > 1)
+      throw std::runtime_error("functor");
+  }
+
+  void operator()() const { }
+
+  int copies;
+};
+
+
+void
+test01()
+{
+  std::tr1::function<void()> f = functor();
+  try {
+    std::tr1::function<void()> g = f;
+  } catch (const std::runtime_error& e) {
+    return;
+  }
+  VERIFY(false);
+}
+
+int
+main()
+{
+  test01();
+}