1 files changed, 122 insertions, 0 deletions
diff --git a/libgomp/config/linux/bar.c b/libgomp/config/linux/bar.c
new file mode 100644
index 000000000..3e0379eb6
--- /dev/null
+++ b/libgomp/config/linux/bar.c
@@ -0,0 +1,122 @@
+/* Copyright (C) 2005, 2008, 2009 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 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 is a Linux specific implementation of a barrier synchronization
+   mechanism for libgomp.  This type is private to the library.  This 
+   implementation uses atomic instructions and the futex syscall.  */
+
+#include <limits.h>
+#include "wait.h"
+
+
+void
+gomp_barrier_wait_end (gomp_barrier_t *bar, gomp_barrier_state_t state)
+{
+  if (__builtin_expect ((state & 1) != 0, 0))
+    {
+      /* Next time we'll be awaiting TOTAL threads again.  */
+      bar->awaited = bar->total;
+      atomic_write_barrier ();
+      bar->generation += 4;
+      futex_wake ((int *) &bar->generation, INT_MAX);
+    }
+  else
+    {
+      unsigned int generation = state;
+
+      do
+	do_wait ((int *) &bar->generation, generation);
+      while (bar->generation == generation);
+    }
+}
+
+void
+gomp_barrier_wait (gomp_barrier_t *bar)
+{
+  gomp_barrier_wait_end (bar, gomp_barrier_wait_start (bar));
+}
+
+/* Like gomp_barrier_wait, except that if the encountering thread
+   is not the last one to hit the barrier, it returns immediately.
+   The intended usage is that a thread which intends to gomp_barrier_destroy
+   this barrier calls gomp_barrier_wait, while all other threads
+   call gomp_barrier_wait_last.  When gomp_barrier_wait returns,
+   the barrier can be safely destroyed.  */
+
+void
+gomp_barrier_wait_last (gomp_barrier_t *bar)
+{
+  gomp_barrier_state_t state = gomp_barrier_wait_start (bar);
+  if (state & 1)
+    gomp_barrier_wait_end (bar, state);
+}
+
+void
+gomp_team_barrier_wake (gomp_barrier_t *bar, int count)
+{
+  futex_wake ((int *) &bar->generation, count == 0 ? INT_MAX : count);
+}
+
+void
+gomp_team_barrier_wait_end (gomp_barrier_t *bar, gomp_barrier_state_t state)
+{
+  unsigned int generation;
+
+  if (__builtin_expect ((state & 1) != 0, 0))
+    {
+      /* Next time we'll be awaiting TOTAL threads again.  */
+      struct gomp_thread *thr = gomp_thread ();
+      struct gomp_team *team = thr->ts.team;
+      bar->awaited = bar->total;
+      atomic_write_barrier ();
+      if (__builtin_expect (team->task_count, 0))
+	{
+	  gomp_barrier_handle_tasks (state);
+	  state &= ~1;
+	}
+      else
+	{
+	  bar->generation = state + 3;
+	  futex_wake ((int *) &bar->generation, INT_MAX);
+	  return;
+	}
+    }
+
+  generation = state;
+  do
+    {
+      do_wait ((int *) &bar->generation, generation);
+      if (__builtin_expect (bar->generation & 1, 0))
+	gomp_barrier_handle_tasks (state);
+      if ((bar->generation & 2))
+	generation |= 2;
+    }
+  while (bar->generation != state + 4);
+}
+
+void
+gomp_team_barrier_wait (gomp_barrier_t *bar)
+{
+  gomp_team_barrier_wait_end (bar, gomp_barrier_wait_start (bar));
+}