1 /* Copyright (C) 2005 Free Software Foundation, Inc. 2 Contributed by Richard Henderson <rth@redhat.com>. 3 4 This file is part of the GNU OpenMP Library (libgomp). 5 6 Libgomp is free software; you can redistribute it and/or modify it 7 under the terms of the GNU Lesser General Public License as published by 8 the Free Software Foundation; either version 2.1 of the License, or 9 (at your option) any later version. 10 11 Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY 12 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 13 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for 14 more details. 15 16 You should have received a copy of the GNU Lesser General Public License 17 along with libgomp; see the file COPYING.LIB. If not, write to the 18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 19 MA 02110-1301, USA. */ 20 21 /* As a special exception, if you link this library with other files, some 22 of which are compiled with GCC, to produce an executable, this library 23 does not by itself cause the resulting executable to be covered by the 24 GNU General Public License. This exception does not however invalidate 25 any other reasons why the executable file might be covered by the GNU 26 General Public License. */ 27 28 /* This file handles the CRITICAL construct. */ 29 30 #include "libgomp.h" 31 #include <stdlib.h> 32 33 34 static gomp_mutex_t default_lock; 35 36 void 37 GOMP_critical_start (void) 38 { 39 gomp_mutex_lock (&default_lock); 40 } 41 42 void 43 GOMP_critical_end (void) 44 { 45 gomp_mutex_unlock (&default_lock); 46 } 47 48 #ifndef HAVE_SYNC_BUILTINS 49 static gomp_mutex_t create_lock_lock; 50 #endif 51 52 void 53 GOMP_critical_name_start (void **pptr) 54 { 55 gomp_mutex_t *plock; 56 57 /* If a mutex fits within the space for a pointer, and is zero initialized, 58 then use the pointer space directly. */ 59 if (GOMP_MUTEX_INIT_0 60 && sizeof (gomp_mutex_t) <= sizeof (void *) 61 && __alignof (gomp_mutex_t) <= sizeof (void *)) 62 plock = (gomp_mutex_t *)pptr; 63 64 /* Otherwise we have to be prepared to malloc storage. */ 65 else 66 { 67 plock = *pptr; 68 69 if (plock == NULL) 70 { 71 #ifdef HAVE_SYNC_BUILTINS 72 gomp_mutex_t *nlock = gomp_malloc (sizeof (gomp_mutex_t)); 73 gomp_mutex_init (nlock); 74 75 plock = __sync_val_compare_and_swap (pptr, NULL, nlock); 76 if (plock != NULL) 77 { 78 gomp_mutex_destroy (nlock); 79 free (nlock); 80 } 81 else 82 plock = nlock; 83 #else 84 gomp_mutex_lock (&create_lock_lock); 85 plock = *pptr; 86 if (plock == NULL) 87 { 88 plock = gomp_malloc (sizeof (gomp_mutex_t)); 89 gomp_mutex_init (plock); 90 __sync_synchronize (); 91 *pptr = plock; 92 } 93 gomp_mutex_unlock (&create_lock_lock); 94 #endif 95 } 96 } 97 98 gomp_mutex_lock (plock); 99 } 100 101 void 102 GOMP_critical_name_end (void **pptr) 103 { 104 gomp_mutex_t *plock; 105 106 /* If a mutex fits within the space for a pointer, and is zero initialized, 107 then use the pointer space directly. */ 108 if (GOMP_MUTEX_INIT_0 109 && sizeof (gomp_mutex_t) <= sizeof (void *) 110 && __alignof (gomp_mutex_t) <= sizeof (void *)) 111 plock = (gomp_mutex_t *)pptr; 112 else 113 plock = *pptr; 114 115 gomp_mutex_unlock (plock); 116 } 117 118 /* This mutex is used when atomic operations don't exist for the target 119 in the mode requested. The result is not globally atomic, but works so 120 long as all parallel references are within #pragma omp atomic directives. 121 According to responses received from omp@openmp.org, appears to be within 122 spec. Which makes sense, since that's how several other compilers 123 handle this situation as well. */ 124 125 static gomp_mutex_t atomic_lock; 126 127 void 128 GOMP_atomic_start (void) 129 { 130 gomp_mutex_lock (&atomic_lock); 131 } 132 133 void 134 GOMP_atomic_end (void) 135 { 136 gomp_mutex_unlock (&atomic_lock); 137 } 138 139 #if !GOMP_MUTEX_INIT_0 140 static void __attribute__((constructor)) 141 initialize_critical (void) 142 { 143 gomp_mutex_init (&default_lock); 144 gomp_mutex_init (&atomic_lock); 145 #ifndef HAVE_SYNC_BUILTINS 146 gomp_mutex_init (&create_lock_lock); 147 #endif 148 } 149 #endif 150