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Diffstat (limited to 'libgomp/critical.c')
| -rw-r--r-- | libgomp/critical.c | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/libgomp/critical.c b/libgomp/critical.c new file mode 100644 index 00000000000..70159ec7a6e --- /dev/null +++ b/libgomp/critical.c @@ -0,0 +1,147 @@ +/* Copyright (C) 2005 Free Software Foundation, Inc. + Contributed by Richard Henderson <rth@redhat.com>. + + This file is part of the GNU OpenMP Library (libgomp). + + Libgomp is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, 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 Lesser General Public License for + more details. + + You should have received a copy of the GNU Lesser General Public License + along with libgomp; see the file COPYING.LIB. If not, write to the + Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, + MA 02110-1301, USA. */ + +/* As a special exception, if you link this library with other files, some + of which are compiled with GCC, to produce an executable, this library + does not by itself cause the resulting executable to be covered by the + GNU General Public License. This exception does not however invalidate + any other reasons why the executable file might be covered by the GNU + General Public License. */ + +/* This file handles the CRITICAL construct. */ + +#include "libgomp.h" +#include <stdlib.h> + + +static gomp_mutex_t default_lock; + +void +GOMP_critical_start (void) +{ + 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, plock, nlock); + if (plock != nlock) + { + gomp_mutex_destroy (nlock); + free (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); +} + +/* This mutex is used when atomic operations don't exist for the target + in the mode requested. The result is not globally atomic, but works so + long as all parallel references are within #pragma omp atomic directives. + According to responses received from omp@openmp.org, appears to be within + spec. Which makes sense, since that's how several other compilers + handle this situation as well. */ + +static gomp_mutex_t atomic_lock; + +void +GOMP_atomic_start (void) +{ + gomp_mutex_lock (&atomic_lock); +} + +void +GOMP_atomic_end (void) +{ + gomp_mutex_unlock (&atomic_lock); +} + +#if !GOMP_MUTEX_INIT_0 +static void __attribute__((constructor)) +initialize_critical (void) +{ + gomp_mutex_init (&default_lock); + gomp_mutex_init (&atomic_lock); +#ifndef HAVE_SYNC_BUILTINS + gomp_mutex_init (&create_lock_lock); +#endif +} +#endif |