150 lines
3.9 KiB
C
150 lines
3.9 KiB
C
/* Copyright (C) 2005 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 OpenMP Library (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 Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) 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 Lesser General Public License for
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more details.
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You should have received a copy of the GNU Lesser General Public License
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along with libgomp; see the file COPYING.LIB. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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MA 02110-1301, USA. */
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/* As a special exception, if you link this library with other files, some
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of which are compiled with GCC, to produce an executable, this library
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does not by itself cause the resulting executable to be covered by the
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GNU General Public License. This exception does not however invalidate
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any other reasons why the executable file might be covered by the GNU
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General Public License. */
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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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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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/* This mutex is used when atomic operations don't exist for the target
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in the mode requested. The result is not globally atomic, but works so
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long as all parallel references are within #pragma omp atomic directives.
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According to responses received from omp@openmp.org, appears to be within
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spec. Which makes sense, since that's how several other compilers
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handle this situation as well. */
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static gomp_mutex_t atomic_lock;
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void
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GOMP_atomic_start (void)
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{
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gomp_mutex_lock (&atomic_lock);
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}
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void
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GOMP_atomic_end (void)
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{
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gomp_mutex_unlock (&atomic_lock);
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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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gomp_mutex_init (&atomic_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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