PR libstdc++/81891 fix double-free in hashtable constructor

PR libstdc++/81891
	* include/bits/hashtable.h (_Hashtable(_InputIterator, _InputIterator,
	size_type, const _H1&, const _H2&, const _Hash&, const _Equal&,
	const _ExtractKey&, const allocator_type&)): Let destructor do clean
	up if an exception is thrown.
	* testsuite/23_containers/unordered_map/cons/81891.cc: New.

From-SVN: r251185

libstdc++-v3/ChangeLog

@@ -1,3 +1,12 @@
+2017-08-18  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/81891
+	* include/bits/hashtable.h (_Hashtable(_InputIterator, _InputIterator,
+	size_type, const _H1&, const _H2&, const _Hash&, const _Equal&,
+	const _ExtractKey&, const allocator_type&)): Let destructor do clean
+	up if an exception is thrown.
+	* testsuite/23_containers/unordered_map/cons/81891.cc: New.
+
 2017-08-11  Jonathan Wakely  <jwakely@redhat.com>
 
 	PR libstdc++/81808

libstdc++-v3/include/bits/hashtable.h

@@ -973,17 +973,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	    _M_bucket_count = __bkt_count;
 	  }
 
-	__try
+	for (; __f != __l; ++__f)
-	  {
+	  this->insert(*__f);
-	    for (; __f != __l; ++__f)
-	      this->insert(*__f);
-	  }
-	__catch(...)
-	  {
-	    clear();
-	    _M_deallocate_buckets();
-	    __throw_exception_again;
-	  }
       }
 
   template<typename _Key, typename _Value,

libstdc++-v3/testsuite/23_containers/unordered_map/cons/81891.cc

@@ -0,0 +1,68 @@
+// 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 } }
+
+#include <unordered_map>
+#include <testsuite_hooks.h>
+#include <testsuite_allocator.h>
+
+struct fails_on_copy {
+  fails_on_copy() = default;
+  fails_on_copy(const fails_on_copy&) { throw 0; };
+};
+
+using value_type = std::pair<int, fails_on_copy>;
+
+void
+test01()
+{
+  value_type p;
+  try
+  {
+    std::unordered_map<int, fails_on_copy> umap(&p, &p + 1);
+  }
+  catch(...)
+  { }
+}
+
+void
+test02()
+{
+  using Alloc = __gnu_test::tracker_allocator<value_type>;
+  using std::hash;
+  using std::equal_to;
+
+  value_type p;
+  try
+  {
+    std::unordered_map<int, fails_on_copy, hash<int>, equal_to<int>, Alloc>
+	umap(&p, &p + 1);
+  }
+  catch(...)
+  { }
+
+  using counter = __gnu_test::tracker_allocator_counter;
+  VERIFY(counter::get_allocation_count() == counter::get_deallocation_count());
+}
+
+int
+main()
+{
+  test01();
+  test02();
+}