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/* Copyright (C) 2005-2020 Free Software Foundation, Inc.
Contributed by Richard Henderson <rth@redhat.com>.
This file is part of the GNU Offloading and Multi Processing Library
(libgomp).
Libgomp 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.
Libgomp 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/>. */
/* This file handles the CRITICAL construct. */
#include "libgomp.h"
#include <stdlib.h>
static gomp_mutex_t default_lock;
void
GOMP_critical_start (void)
{
/* There is an implicit flush on entry to a critical region. */
__atomic_thread_fence (MEMMODEL_RELEASE);
gomp_mutex_lock (&default_lock);
}
void
GOMP_critical_end (void)
{
gomp_mutex_unlock (&default_lock);
}
#ifndef HAVE_SYNC_BUILTINS
static gomp_mutex_t create_lock_lock;
#endif
void
GOMP_critical_name_start (void **pptr)
{
gomp_mutex_t *plock;
/* If a mutex fits within the space for a pointer, and is zero initialized,
then use the pointer space directly. */
if (GOMP_MUTEX_INIT_0
&& sizeof (gomp_mutex_t) <= sizeof (void *)
&& __alignof (gomp_mutex_t) <= sizeof (void *))
plock = (gomp_mutex_t *)pptr;
/* Otherwise we have to be prepared to malloc storage. */
else
{
plock = *pptr;
if (plock == NULL)
{
#ifdef HAVE_SYNC_BUILTINS
gomp_mutex_t *nlock = gomp_malloc (sizeof (gomp_mutex_t));
gomp_mutex_init (nlock);
plock = __sync_val_compare_and_swap (pptr, NULL, nlock);
if (plock != NULL)
{
gomp_mutex_destroy (nlock);
free (nlock);
}
else
plock = nlock;
#else
gomp_mutex_lock (&create_lock_lock);
plock = *pptr;
if (plock == NULL)
{
plock = gomp_malloc (sizeof (gomp_mutex_t));
gomp_mutex_init (plock);
__sync_synchronize ();
*pptr = plock;
}
gomp_mutex_unlock (&create_lock_lock);
#endif
}
}
gomp_mutex_lock (plock);
}
void
GOMP_critical_name_end (void **pptr)
{
gomp_mutex_t *plock;
/* If a mutex fits within the space for a pointer, and is zero initialized,
then use the pointer space directly. */
if (GOMP_MUTEX_INIT_0
&& sizeof (gomp_mutex_t) <= sizeof (void *)
&& __alignof (gomp_mutex_t) <= sizeof (void *))
plock = (gomp_mutex_t *)pptr;
else
plock = *pptr;
gomp_mutex_unlock (plock);
}
#if !GOMP_MUTEX_INIT_0
static void __attribute__((constructor))
initialize_critical (void)
{
gomp_mutex_init (&default_lock);
#ifndef HAVE_SYNC_BUILTINS
gomp_mutex_init (&create_lock_lock);
#endif
}
#endif
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