| /* 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 |