125 lines
2.9 KiB
C
125 lines
2.9 KiB
C
/* Copyright (C) 2005-2018 Free Software Foundation, Inc.
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Contributed by Richard Henderson <rth@redhat.com>.
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This file is part of the GNU Offloading and Multi Processing Library
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(libgomp).
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Libgomp is free software; you can redistribute it and/or modify it
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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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Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details.
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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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/* This is the default POSIX 1003.1b implementation of a semaphore
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synchronization mechanism for libgomp. This type is private to
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the library.
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This is a bit heavy weight for what we need, in that we're not
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interested in sem_wait as a cancelation point, but it's not too
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bad for a default. */
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#include "libgomp.h"
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#ifdef HAVE_BROKEN_POSIX_SEMAPHORES
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#include <stdlib.h>
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void gomp_sem_init (gomp_sem_t *sem, int value)
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{
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int ret;
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ret = pthread_mutex_init (&sem->mutex, NULL);
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if (ret)
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return;
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ret = pthread_cond_init (&sem->cond, NULL);
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if (ret)
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return;
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sem->value = value;
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}
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void gomp_sem_wait (gomp_sem_t *sem)
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{
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int ret;
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ret = pthread_mutex_lock (&sem->mutex);
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if (ret)
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return;
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if (sem->value > 0)
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{
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sem->value--;
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ret = pthread_mutex_unlock (&sem->mutex);
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return;
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}
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while (sem->value <= 0)
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{
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ret = pthread_cond_wait (&sem->cond, &sem->mutex);
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if (ret)
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{
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pthread_mutex_unlock (&sem->mutex);
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return;
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}
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}
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sem->value--;
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ret = pthread_mutex_unlock (&sem->mutex);
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return;
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}
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void gomp_sem_post (gomp_sem_t *sem)
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{
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int ret;
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ret = pthread_mutex_lock (&sem->mutex);
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if (ret)
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return;
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sem->value++;
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ret = pthread_mutex_unlock (&sem->mutex);
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if (ret)
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return;
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ret = pthread_cond_signal (&sem->cond);
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return;
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}
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void gomp_sem_destroy (gomp_sem_t *sem)
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{
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int ret;
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ret = pthread_mutex_destroy (&sem->mutex);
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if (ret)
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return;
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ret = pthread_cond_destroy (&sem->cond);
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return;
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}
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#else /* HAVE_BROKEN_POSIX_SEMAPHORES */
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void
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gomp_sem_wait (gomp_sem_t *sem)
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{
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/* With POSIX, the wait can be canceled by signals. We don't want that.
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It is expected that the return value here is -1 and errno is EINTR. */
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while (sem_wait (sem) != 0)
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continue;
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}
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#endif
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