128 lines
3.2 KiB
C
128 lines
3.2 KiB
C
/* Copyright (C) 2005-2017 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 file handles the CRITICAL construct. */
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#include "libgomp.h"
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#include <stdlib.h>
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static gomp_mutex_t default_lock;
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void
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GOMP_critical_start (void)
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{
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/* There is an implicit flush on entry to a critical region. */
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__atomic_thread_fence (MEMMODEL_RELEASE);
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gomp_mutex_lock (&default_lock);
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}
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void
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GOMP_critical_end (void)
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{
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gomp_mutex_unlock (&default_lock);
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}
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#ifndef HAVE_SYNC_BUILTINS
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static gomp_mutex_t create_lock_lock;
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#endif
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void
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GOMP_critical_name_start (void **pptr)
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{
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gomp_mutex_t *plock;
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/* If a mutex fits within the space for a pointer, and is zero initialized,
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then use the pointer space directly. */
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if (GOMP_MUTEX_INIT_0
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&& sizeof (gomp_mutex_t) <= sizeof (void *)
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&& __alignof (gomp_mutex_t) <= sizeof (void *))
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plock = (gomp_mutex_t *)pptr;
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/* Otherwise we have to be prepared to malloc storage. */
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else
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{
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plock = *pptr;
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if (plock == NULL)
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{
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#ifdef HAVE_SYNC_BUILTINS
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gomp_mutex_t *nlock = gomp_malloc (sizeof (gomp_mutex_t));
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gomp_mutex_init (nlock);
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plock = __sync_val_compare_and_swap (pptr, NULL, nlock);
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if (plock != NULL)
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{
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gomp_mutex_destroy (nlock);
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free (nlock);
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}
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else
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plock = nlock;
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#else
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gomp_mutex_lock (&create_lock_lock);
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plock = *pptr;
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if (plock == NULL)
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{
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plock = gomp_malloc (sizeof (gomp_mutex_t));
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gomp_mutex_init (plock);
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__sync_synchronize ();
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*pptr = plock;
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}
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gomp_mutex_unlock (&create_lock_lock);
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#endif
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}
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}
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gomp_mutex_lock (plock);
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}
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void
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GOMP_critical_name_end (void **pptr)
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{
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gomp_mutex_t *plock;
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/* If a mutex fits within the space for a pointer, and is zero initialized,
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then use the pointer space directly. */
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if (GOMP_MUTEX_INIT_0
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&& sizeof (gomp_mutex_t) <= sizeof (void *)
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&& __alignof (gomp_mutex_t) <= sizeof (void *))
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plock = (gomp_mutex_t *)pptr;
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else
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plock = *pptr;
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gomp_mutex_unlock (plock);
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}
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#if !GOMP_MUTEX_INIT_0
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static void __attribute__((constructor))
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initialize_critical (void)
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{
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gomp_mutex_init (&default_lock);
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#ifndef HAVE_SYNC_BUILTINS
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gomp_mutex_init (&create_lock_lock);
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#endif
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}
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#endif
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