85 lines
2.5 KiB
C++
85 lines
2.5 KiB
C++
// Exception Handling support header for -*- C++ -*-
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// Copyright (C) 2016-2021 Free Software Foundation, Inc.
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//
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// This file is part of GCC.
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//
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// GCC is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 3, or (at your option)
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// any later version.
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//
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// GCC is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file eh_atomics.h
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* This is an internal header file, included by library source files.
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* Do not attempt to use it directly.
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*/
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#ifndef _EH_ATOMICS_H
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#define _EH_ATOMICS_H 1
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#include <bits/c++config.h>
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#include <bits/atomic_word.h>
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#include <bits/atomic_lockfree_defines.h>
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#if ATOMIC_INT_LOCK_FREE <= 1
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# include <ext/atomicity.h>
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#endif
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#pragma GCC visibility push(default)
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extern "C++" {
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namespace __gnu_cxx
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{
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void
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__eh_atomic_inc (_Atomic_word* __count) __attribute__((always_inline));
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bool
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__eh_atomic_dec (_Atomic_word* __count) __attribute__((always_inline));
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// Increments the count.
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inline void
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__eh_atomic_inc (_Atomic_word* __count)
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{
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#if ATOMIC_INT_LOCK_FREE > 1
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__atomic_add_fetch (__count, 1, __ATOMIC_ACQ_REL);
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#else
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_GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE (__count);
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__gnu_cxx::__atomic_add_dispatch (__count, 1);
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_GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER (__count);
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#endif
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}
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// Decrements the count and returns true if it reached zero.
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inline bool
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__eh_atomic_dec (_Atomic_word* __count)
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{
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#if ATOMIC_INT_LOCK_FREE > 1
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return __atomic_sub_fetch (__count, 1, __ATOMIC_ACQ_REL) == 0;
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#else
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_GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE (__count);
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if (__gnu_cxx::__exchange_and_add_dispatch (__count, -1) == 1)
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{
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_GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER (__count);
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return true;
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}
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return false;
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#endif
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}
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} // namespace __gnu_cxx
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}
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#pragma GCC visibility pop
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#endif // _EH_ATOMICS_H
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