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[v3 PATCH] basic_string spurious use of a default constructible allocator - LWG2788
- From: Nina Dinka Ranns <dinka dot ranns at gmail dot com>
- To: gcc-patches List <gcc-patches at gcc dot gnu dot org>, "libstdc++" <libstdc++ at gcc dot gnu dot org>
- Date: Mon, 27 May 2019 11:53:20 +0100
- Subject: [v3 PATCH] basic_string spurious use of a default constructible allocator - LWG2788
Tested on Linux x86_64
basic_string spurious use of a default constructible allocator - LWG2788
2019-05-27 Nina Dinka Ranns <dinka.ranns@gmail.com>
basic_string spurious use of a default constructible allocator - LWG2788
* bits/basic_string.tcc:
(_M_replace_dispatch()): string temporary now constructed with
the current allocator
* testsuite/21_strings/basic_string/allocator/char/lwg2788.cc: New
* testsuite/21_strings/basic_string/allocator/wchar_t/lwg2788.cc: New
Index: libstdc++-v3/include/bits/basic_string.tcc
===================================================================
--- libstdc++-v3/include/bits/basic_string.tcc (revision 271509)
+++ libstdc++-v3/include/bits/basic_string.tcc (working copy)
@@ -381,7 +381,9 @@
_InputIterator __k1, _InputIterator __k2,
std::__false_type)
{
- const basic_string __s(__k1, __k2);
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // 2788. unintentionally require a default constructible allocator
+ const basic_string __s(__k1, __k2, this->get_allocator());
const size_type __n1 = __i2 - __i1;
return _M_replace(__i1 - begin(), __n1, __s._M_data(),
__s.size());
Index: libstdc++-v3/testsuite/20_util/nonesuch/nonesuch.cc
===================================================================
--- libstdc++-v3/testsuite/20_util/nonesuch/nonesuch.cc (revision 271509)
+++ libstdc++-v3/testsuite/20_util/nonesuch/nonesuch.cc (nonexistent)
@@ -1,39 +0,0 @@
-// 2019-05-14 Nina Dinka Ranns <dinka.ranns@gmail.com>
-// Copyright (C) 2019 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 compile { target c++14 } }
-
-#include <type_traits>
-// Example taken from LWG2960
-
-using std::__nonesuch;
-struct such {};
-void f(const such&){};
-void f(const std::__nonesuch&);
-
-int main(){
- static_assert(!std::is_default_constructible<__nonesuch>::value,
- "__nonesuch is default constructible");
- static_assert(!std::is_copy_constructible<__nonesuch>::value,
- "__nonesuch is copy constructible");
- static_assert(!std::is_assignable<__nonesuch, __nonesuch>::value,
- "__nonesuch is assignable");
- static_assert(!std::is_destructible<__nonesuch>::value,
- "__nonesuch is destructible");
- f({});
-}
Index: libstdc++-v3/testsuite/21_strings/basic_string/allocator/char/lwg2788.cc
===================================================================
--- libstdc++-v3/testsuite/21_strings/basic_string/allocator/char/lwg2788.cc (nonexistent)
+++ libstdc++-v3/testsuite/21_strings/basic_string/allocator/char/lwg2788.cc (working copy)
@@ -0,0 +1,84 @@
+//{ dg-do run { target c++11 } }
+
+// 2019-05-27 Nina Dinka Ranns <dinka.ranns@gmail.com>
+//
+// Copyright (C) 2015-2019 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 <string>
+#include <testsuite_hooks.h>
+
+using C = char;
+using traits = std::char_traits<C>;
+int constructCount = 0;
+
+static void resetCounter()
+{
+ constructCount = 0;
+}
+
+template <class Tp>
+struct TestAllocator
+{
+ typedef Tp value_type;
+ using size_type = unsigned;
+
+ TestAllocator() noexcept { constructCount++; }
+
+ template <class T>
+ TestAllocator(const TestAllocator<T>&) {}
+
+ Tp *allocate(std::size_t n)
+ { return std::allocator<Tp>().allocate(n); }
+
+ void deallocate(Tp *p, std::size_t n)
+ { std::allocator<Tp>().deallocate(p, n); }
+
+};
+
+template <class T, class U>
+bool operator==(const TestAllocator<T>&, const TestAllocator<U>&)
+{ return true; }
+template <class T, class U>
+bool operator!=(const TestAllocator<T>&, const TestAllocator<U>&)
+{ return false; }
+
+void test01()
+{
+ typedef TestAllocator<C> alloc_type;
+ typedef std::basic_string<C, traits, alloc_type> test_type;
+ test_type v1{alloc_type()};
+ std::string v2{"some_content"};
+
+ resetCounter();
+ v1.assign(v2.begin(),v2.end());
+ VERIFY( constructCount == 0);
+
+ v1.append(v2.begin(),v2.end());
+ VERIFY( constructCount == 0);
+
+ v1.insert(v1.begin(),v1.begin(),v1.end());
+ VERIFY( constructCount == 0);
+
+ v1.replace(v1.begin(),v1.end(),v1.begin(),v1.end());
+ VERIFY( constructCount == 0);
+}
+int main()
+{
+ test01();
+ return 0;
+}
Index: libstdc++-v3/testsuite/21_strings/basic_string/allocator/wchar_t/lwg2788.cc
===================================================================
--- libstdc++-v3/testsuite/21_strings/basic_string/allocator/wchar_t/lwg2788.cc (nonexistent)
+++ libstdc++-v3/testsuite/21_strings/basic_string/allocator/wchar_t/lwg2788.cc (working copy)
@@ -0,0 +1,84 @@
+//{ dg-do run { target c++11 } }
+
+// 2019-05-27 Nina Dinka Ranns <dinka.ranns@gmail.com>
+//
+// Copyright (C) 2015-2019 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 <string>
+#include <testsuite_hooks.h>
+
+using C = wchar_t;
+using traits = std::char_traits<C>;
+int constructCount = 0;
+
+static void resetCounter()
+{
+ constructCount = 0;
+}
+
+template <class Tp>
+struct TestAllocator
+{
+ typedef Tp value_type;
+ using size_type = unsigned;
+
+ TestAllocator() noexcept { constructCount++; }
+
+ template <class T>
+ TestAllocator(const TestAllocator<T>&) {}
+
+ Tp *allocate(std::size_t n)
+ { return std::allocator<Tp>().allocate(n); }
+
+ void deallocate(Tp *p, std::size_t n)
+ { std::allocator<Tp>().deallocate(p, n); }
+
+};
+
+template <class T, class U>
+bool operator==(const TestAllocator<T>&, const TestAllocator<U>&)
+{ return true; }
+template <class T, class U>
+bool operator!=(const TestAllocator<T>&, const TestAllocator<U>&)
+{ return false; }
+
+void test01()
+{
+ typedef TestAllocator<C> alloc_type;
+ typedef std::basic_string<C, traits, alloc_type> test_type;
+ test_type v1{alloc_type()};
+ std::wstring v2{L"some_content"};
+
+ resetCounter();
+ v1.assign(v2.begin(),v2.end());
+ VERIFY( constructCount == 0);
+
+ v1.append(v2.begin(),v2.end());
+ VERIFY( constructCount == 0);
+
+ v1.insert(v1.begin(),v1.begin(),v1.end());
+ VERIFY( constructCount == 0);
+
+ v1.replace(v1.begin(),v1.end(),v1.begin(),v1.end());
+ VERIFY( constructCount == 0);
+}
+int main()
+{
+ test01();
+ return 0;
+}