libstdc++: make polymorphic_allocator throw consistent type (LWG 3237)

	* include/std/memory_resource (polymorphic_allocator::allocate)
	(polymorphic_allocator::allocate_object): Change type of exception to
	bad_array_new_length (LWG 3237).
	* testsuite/20_util/polymorphic_allocator/lwg3237.cc: New test.

libstdc++-v3/ChangeLog

 2020-02-19  Jonathan Wakely  <jwakely@redhat.com>
 
+	* include/std/memory_resource (polymorphic_allocator::allocate)
+	(polymorphic_allocator::allocate_object): Change type of exception to
+	bad_array_new_length (LWG 3237).
+	* testsuite/20_util/polymorphic_allocator/lwg3237.cc: New test.
+
 	* include/std/type_traits (__cpp_lib_unwrap_ref): Define (LWG 3348).
 	* include/std/version (__cpp_lib_unwrap_ref): Likewise.
 	* testsuite/20_util/unwrap_reference/1.cc: Check macro.

libstdc++-v3/include/std/memory_resource

@@ -167,7 +167,7 @@ namespace pmr
       __attribute__((__returns_nonnull__))
       {
 	if (__n > (__detail::__int_limits<size_t>::max() / sizeof(_Tp)))
-	  std::__throw_bad_alloc();
+	  _GLIBCXX_THROW_OR_ABORT(bad_array_new_length());
 	return static_cast<_Tp*>(_M_resource->allocate(__n * sizeof(_Tp),
 						       alignof(_Tp)));
       }
@@ -193,7 +193,7 @@ namespace pmr
 	allocate_object(size_t __n = 1)
 	{
 	  if ((__detail::__int_limits<size_t>::max() / sizeof(_Up)) < __n)
-	    __throw_length_error("polymorphic_allocator::allocate_object");
+	    _GLIBCXX_THROW_OR_ABORT(bad_array_new_length());
 	  return static_cast<_Up*>(allocate_bytes(__n * sizeof(_Up),
 						  alignof(_Up)));
 	}

libstdc++-v3/testsuite/20_util/polymorphic_allocator/lwg3237.cc

+// Copyright (C) 2020 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++2a" }
+// { dg-do run { target c++2a } }
+
+#include <memory_resource>
+#include <testsuite_hooks.h>
+
+struct large { alignas(1024) int i; };
+
+void
+test01()
+{
+  std::pmr::polymorphic_allocator<large> a;
+  large* p = nullptr;
+  try
+  {
+    p = a.allocate(std::size_t(-1) / 256);
+    VERIFY( false );
+  }
+  catch (const std::bad_array_new_length&)
+  {
+  }
+
+  std::pmr::polymorphic_allocator<int> a2;
+  try
+  {
+    p = a2.allocate_object<large>(std::size_t(-1) / 256);
+    VERIFY( false );
+  }
+  catch (const std::bad_array_new_length&)
+  {
+  }
+}
+
+int
+main()
+{
+  test01();
+}