1  /* Copyright (C) 2005-2023 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 handles the SINGLE construct.  */
      27  
      28  #include "libgomp.h"
      29  
      30  
      31  /* This routine is called when first encountering a SINGLE construct that
      32     doesn't have a COPYPRIVATE clause.  Returns true if this is the thread
      33     that should execute the clause.  */
      34  
      35  bool
      36  GOMP_single_start (void)
      37  {
      38  #ifdef HAVE_SYNC_BUILTINS
      39    struct gomp_thread *thr = gomp_thread ();
      40    struct gomp_team *team = thr->ts.team;
      41    unsigned long single_count;
      42  
      43    if (__builtin_expect (team == NULL, 0))
      44      return true;
      45  
      46    single_count = thr->ts.single_count++;
      47    return __sync_bool_compare_and_swap (&team->single_count, single_count,
      48  				       single_count + 1L);
      49  #else
      50    bool ret = gomp_work_share_start (0);
      51    if (ret)
      52      gomp_work_share_init_done ();
      53    gomp_work_share_end_nowait ();
      54    return ret;
      55  #endif
      56  }
      57  
      58  /* This routine is called when first encountering a SINGLE construct that
      59     does have a COPYPRIVATE clause.  Returns NULL if this is the thread
      60     that should execute the clause; otherwise the return value is pointer
      61     given to GOMP_single_copy_end by the thread that did execute the clause.  */
      62  
      63  void *
      64  GOMP_single_copy_start (void)
      65  {
      66    struct gomp_thread *thr = gomp_thread ();
      67  
      68    bool first;
      69    void *ret;
      70  
      71    first = gomp_work_share_start (0);
      72    
      73    if (first)
      74      {
      75        gomp_work_share_init_done ();
      76        ret = NULL;
      77      }
      78    else
      79      {
      80        gomp_team_barrier_wait (&thr->ts.team->barrier);
      81  
      82        ret = thr->ts.work_share->copyprivate;
      83        gomp_work_share_end_nowait ();
      84      }
      85  
      86    return ret;
      87  }
      88  
      89  /* This routine is called when the thread that entered a SINGLE construct
      90     with a COPYPRIVATE clause gets to the end of the construct.  */
      91  
      92  void
      93  GOMP_single_copy_end (void *data)
      94  {
      95    struct gomp_thread *thr = gomp_thread ();
      96    struct gomp_team *team = thr->ts.team;
      97  
      98    if (team != NULL)
      99      {
     100        thr->ts.work_share->copyprivate = data;
     101        gomp_team_barrier_wait (&team->barrier);
     102      }
     103  
     104    gomp_work_share_end_nowait ();
     105  }