8d9254fc8a
From-SVN: r279813
117 lines
3.4 KiB
C++
117 lines
3.4 KiB
C++
// Support for atomic operations -*- C++ -*-
|
|
|
|
// Copyright (C) 2004-2020 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.
|
|
|
|
// Under Section 7 of GPL version 3, you are granted additional
|
|
// permissions described in the GCC Runtime Library Exception, version
|
|
// 3.1, as published by the Free Software Foundation.
|
|
|
|
// You should have received a copy of the GNU General Public License and
|
|
// a copy of the GCC Runtime Library Exception along with this program;
|
|
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|
// <http://www.gnu.org/licenses/>.
|
|
|
|
/** @file ext/atomicity.h
|
|
* This file is a GNU extension to the Standard C++ Library.
|
|
*/
|
|
|
|
#ifndef _GLIBCXX_ATOMICITY_H
|
|
#define _GLIBCXX_ATOMICITY_H 1
|
|
|
|
#pragma GCC system_header
|
|
|
|
#include <bits/c++config.h>
|
|
#include <bits/gthr.h>
|
|
#include <bits/atomic_word.h>
|
|
|
|
namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
|
|
{
|
|
_GLIBCXX_BEGIN_NAMESPACE_VERSION
|
|
|
|
// Functions for portable atomic access.
|
|
// To abstract locking primitives across all thread policies, use:
|
|
// __exchange_and_add_dispatch
|
|
// __atomic_add_dispatch
|
|
#ifdef _GLIBCXX_ATOMIC_BUILTINS
|
|
inline _Atomic_word
|
|
__attribute__((__always_inline__))
|
|
__exchange_and_add(volatile _Atomic_word* __mem, int __val)
|
|
{ return __atomic_fetch_add(__mem, __val, __ATOMIC_ACQ_REL); }
|
|
|
|
inline void
|
|
__attribute__((__always_inline__))
|
|
__atomic_add(volatile _Atomic_word* __mem, int __val)
|
|
{ __atomic_fetch_add(__mem, __val, __ATOMIC_ACQ_REL); }
|
|
#else
|
|
_Atomic_word
|
|
__exchange_and_add(volatile _Atomic_word*, int) _GLIBCXX_NOTHROW;
|
|
|
|
void
|
|
__atomic_add(volatile _Atomic_word*, int) _GLIBCXX_NOTHROW;
|
|
#endif
|
|
|
|
inline _Atomic_word
|
|
__attribute__((__always_inline__))
|
|
__exchange_and_add_single(_Atomic_word* __mem, int __val)
|
|
{
|
|
_Atomic_word __result = *__mem;
|
|
*__mem += __val;
|
|
return __result;
|
|
}
|
|
|
|
inline void
|
|
__attribute__((__always_inline__))
|
|
__atomic_add_single(_Atomic_word* __mem, int __val)
|
|
{ *__mem += __val; }
|
|
|
|
inline _Atomic_word
|
|
__attribute__ ((__always_inline__))
|
|
__exchange_and_add_dispatch(_Atomic_word* __mem, int __val)
|
|
{
|
|
#ifdef __GTHREADS
|
|
if (__gthread_active_p())
|
|
return __exchange_and_add(__mem, __val);
|
|
#endif
|
|
return __exchange_and_add_single(__mem, __val);
|
|
}
|
|
|
|
inline void
|
|
__attribute__ ((__always_inline__))
|
|
__atomic_add_dispatch(_Atomic_word* __mem, int __val)
|
|
{
|
|
#ifdef __GTHREADS
|
|
if (__gthread_active_p())
|
|
{
|
|
__atomic_add(__mem, __val);
|
|
return;
|
|
}
|
|
#endif
|
|
__atomic_add_single(__mem, __val);
|
|
}
|
|
|
|
_GLIBCXX_END_NAMESPACE_VERSION
|
|
} // namespace
|
|
|
|
// Even if the CPU doesn't need a memory barrier, we need to ensure
|
|
// that the compiler doesn't reorder memory accesses across the
|
|
// barriers.
|
|
#ifndef _GLIBCXX_READ_MEM_BARRIER
|
|
#define _GLIBCXX_READ_MEM_BARRIER __atomic_thread_fence (__ATOMIC_ACQUIRE)
|
|
#endif
|
|
#ifndef _GLIBCXX_WRITE_MEM_BARRIER
|
|
#define _GLIBCXX_WRITE_MEM_BARRIER __atomic_thread_fence (__ATOMIC_RELEASE)
|
|
#endif
|
|
|
|
#endif
|