libgomp/atomic.c

   1 /* Copyright (C) 2005-2024 Free Software Foundation, Inc.
   2    Contributed by Richard Henderson <rth@redhat.com>.
   3
   4    This file is part of the GNU Offloading and Multi Processing Library
   5    (libgomp).
   6
   7    Libgomp is free software; you can redistribute it and/or modify it
   8    under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3, or (at your option)
  10    any later version.
  11
  12    Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
  13    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  14    FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15    more details.
  16
  17    Under Section 7 of GPL version 3, you are granted additional
  18    permissions described in the GCC Runtime Library Exception, version
  19    3.1, as published by the Free Software Foundation.
  20
  21    You should have received a copy of the GNU General Public License and
  22    a copy of the GCC Runtime Library Exception along with this program;
  23    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24    <http://www.gnu.org/licenses/>.  */
  25
  26 /* This file contains helpers for the ATOMIC construct.  */
  27
  28 #include "libgomp.h"
  29
  30 /* This mutex is used when atomic operations don't exist for the target
  31    in the mode requested.  The result is not globally atomic, but works so
  32    long as all parallel references are within #pragma omp atomic directives.
  33    According to responses received from omp@openmp.org, appears to be within
  34    spec.  Which makes sense, since that's how several other compilers
  35    handle this situation as well.  */
  36
  37 static gomp_mutex_t atomic_lock;
  38
  39 void
  40 GOMP_atomic_start (void)
  41 {
  42   gomp_mutex_lock (&atomic_lock);
  43 }
  44
  45 void
  46 GOMP_atomic_end (void)
  47 {
  48   gomp_mutex_unlock (&atomic_lock);
  49 }
  50
  51 #if !GOMP_MUTEX_INIT_0
  52 static void __attribute__((constructor))
  53 initialize_atomic (void)
  54 {
  55   gomp_mutex_init (&atomic_lock);
  56 }
  57 #endif