This fixes an invalid assumption that std::atomic<T> can default
construct a T. It also fixes some variables called "tmp" with
non-uglified names.
PR libstdc++/69301
* include/std/atomic (atomic<T>::load, atomic<T>::exchange): Use
aligned buffer instead of default-initialized variable.
* testsuite/29_atomics/atomic/69301.cc: New test.
* include/experimental/memory (observer_ptr::release): Use reserved
name.
* include/ext/pointer.h (_Pointer_adapter::operator++(int))
(_Pointer_adapter::operator--(int)): Likewise.
Tested powerpc64le-linux, committed to trunk.
commit 22efe5afc1b9838ef0a1569a55c94ba04502140c
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Wed Jan 18 17:55:08 2017 +0000
PR69301 don't assume atomic<T> can default construct T
PR libstdc++/69301
* include/std/atomic (atomic<T>::load, atomic<T>::exchange): Use
aligned buffer instead of default-initialized variable.
* testsuite/29_atomics/atomic/69301.cc: New test.
* include/experimental/memory (observer_ptr::release): Use reserved
name.
* include/ext/pointer.h (_Pointer_adapter::operator++(int))
(_Pointer_adapter::operator--(int)): Likewise.
diff --git a/libstdc++-v3/include/experimental/memory b/libstdc++-v3/include/experimental/memory
index 239afb9..7467674 100644
--- a/libstdc++-v3/include/experimental/memory
+++ b/libstdc++-v3/include/experimental/memory
@@ -124,9 +124,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
constexpr __pointer
release() noexcept
{
- __pointer tmp = get();
+ __pointer __tmp = get();
reset();
- return tmp;
+ return __tmp;
}
constexpr void
diff --git a/libstdc++-v3/include/ext/pointer.h b/libstdc++-v3/include/ext/pointer.h
index f4ba325..8432da0 100644
--- a/libstdc++-v3/include/ext/pointer.h
+++ b/libstdc++-v3/include/ext/pointer.h
@@ -449,9 +449,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
inline _Pointer_adapter
operator++(int)
{
- _Pointer_adapter tmp(*this);
+ _Pointer_adapter __tmp(*this);
_Storage_policy::set(_Storage_policy::get() + 1);
- return tmp;
+ return __tmp;
}
inline _Pointer_adapter&
@@ -464,9 +464,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
inline _Pointer_adapter
operator--(int)
{
- _Pointer_adapter tmp(*this);
+ _Pointer_adapter __tmp(*this);
_Storage_policy::set(_Storage_policy::get() - 1);
- return tmp;
+ return __tmp;
}
}; // class _Pointer_adapter
diff --git a/libstdc++-v3/include/std/atomic b/libstdc++-v3/include/std/atomic
index 7b169e5..5b252a4 100644
--- a/libstdc++-v3/include/std/atomic
+++ b/libstdc++-v3/include/std/atomic
@@ -245,36 +245,40 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_Tp
load(memory_order __m = memory_order_seq_cst) const noexcept
{
- _Tp tmp;
- __atomic_load(std::__addressof(_M_i), std::__addressof(tmp), __m);
- return tmp;
+ alignas(_Tp) unsigned char __buf[sizeof(_Tp)];
+ _Tp* __ptr = reinterpret_cast<_Tp*>(__buf);
+ __atomic_load(std::__addressof(_M_i), __ptr, __m);
+ return *__ptr;
}
_Tp
load(memory_order __m = memory_order_seq_cst) const volatile noexcept
{
- _Tp tmp;
- __atomic_load(std::__addressof(_M_i), std::__addressof(tmp), __m);
- return tmp;
+ alignas(_Tp) unsigned char __buf[sizeof(_Tp)];
+ _Tp* __ptr = reinterpret_cast<_Tp*>(__buf);
+ __atomic_load(std::__addressof(_M_i), __ptr, __m);
+ return *__ptr;
}
_Tp
exchange(_Tp __i, memory_order __m = memory_order_seq_cst) noexcept
{
- _Tp tmp;
+ alignas(_Tp) unsigned char __buf[sizeof(_Tp)];
+ _Tp* __ptr = reinterpret_cast<_Tp*>(__buf);
__atomic_exchange(std::__addressof(_M_i), std::__addressof(__i),
- std::__addressof(tmp), __m);
- return tmp;
+ __ptr, __m);
+ return *__ptr;
}
_Tp
exchange(_Tp __i,
memory_order __m = memory_order_seq_cst) volatile noexcept
{
- _Tp tmp;
+ alignas(_Tp) unsigned char __buf[sizeof(_Tp)];
+ _Tp* __ptr = reinterpret_cast<_Tp*>(__buf);
__atomic_exchange(std::__addressof(_M_i), std::__addressof(__i),
- std::__addressof(tmp), __m);
- return tmp;
+ __ptr, __m);
+ return *__ptr;
}
bool
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic/69301.cc b/libstdc++-v3/testsuite/29_atomics/atomic/69301.cc
new file mode 100644
index 0000000..1af3652
--- /dev/null
+++ b/libstdc++-v3/testsuite/29_atomics/atomic/69301.cc
@@ -0,0 +1,56 @@
+// 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 <atomic>
+#include <testsuite_hooks.h>
+
+struct NonDefaultConstructible
+{
+ NonDefaultConstructible(int i) : val(i) { }
+ int val;
+};
+
+template class std::atomic<NonDefaultConstructible>;
+
+void
+test01()
+{
+ std::atomic<NonDefaultConstructible> a(1);
+ const auto n1 = a.exchange(2);
+ VERIFY( n1.val == 1 );
+ const auto n2 = a.load();
+ VERIFY( n2.val == 2 );
+}
+
+void
+test02()
+{
+ volatile std::atomic<NonDefaultConstructible> a(1);
+ const auto n1 = a.exchange(2);
+ VERIFY( n1.val == 1 );
+ const auto n2 = a.load();
+ VERIFY( n2.val == 2 );
+}
+
+int
+main()
+{
+ test01();
+ test02();
+}
