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- // Exception Handling support header for -*- C++ -*-
- // Copyright (C) 2016-2022 Free Software Foundation, Inc.
- //
- // This file is part of GCC.
- //
- // GCC 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.
- //
- // GCC 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 eh_atomics.h
- * This is an internal header file, included by library source files.
- * Do not attempt to use it directly.
- */
- #ifndef _EH_ATOMICS_H
- #define _EH_ATOMICS_H 1
- #include <bits/c++config.h>
- #include <bits/atomic_word.h>
- #include <bits/atomic_lockfree_defines.h>
- #if ATOMIC_INT_LOCK_FREE <= 1
- # include <ext/atomicity.h>
- #endif
- #pragma GCC visibility push(default)
- extern "C++" {
- namespace __gnu_cxx
- {
- void
- __eh_atomic_inc (_Atomic_word* __count) __attribute__((always_inline));
- bool
- __eh_atomic_dec (_Atomic_word* __count) __attribute__((always_inline));
- // Increments the count.
- inline void
- __eh_atomic_inc (_Atomic_word* __count)
- {
- #if ATOMIC_INT_LOCK_FREE > 1
- __atomic_add_fetch (__count, 1, __ATOMIC_ACQ_REL);
- #else
- _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE (__count);
- __gnu_cxx::__atomic_add_dispatch (__count, 1);
- _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER (__count);
- #endif
- }
- // Decrements the count and returns true if it reached zero.
- inline bool
- __eh_atomic_dec (_Atomic_word* __count)
- {
- #if ATOMIC_INT_LOCK_FREE > 1
- return __atomic_sub_fetch (__count, 1, __ATOMIC_ACQ_REL) == 0;
- #else
- _GLIBCXX_SYNCHRONIZATION_HAPPENS_BEFORE (__count);
- if (__gnu_cxx::__exchange_and_add_dispatch (__count, -1) == 1)
- {
- _GLIBCXX_SYNCHRONIZATION_HAPPENS_AFTER (__count);
- return true;
- }
- return false;
- #endif
- }
- } // namespace __gnu_cxx
- }
- #pragma GCC visibility pop
- #endif // _EH_ATOMICS_H
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