1 files changed, 118 insertions, 0 deletions
diff --git a/libgomp/config/linux/bar.h b/libgomp/config/linux/bar.h
new file mode 100644
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+++ b/libgomp/config/linux/bar.h
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+/* 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.  */
+
+#ifndef GOMP_BARRIER_H
+#define GOMP_BARRIER_H 1
+
+#include "mutex.h"
+
+typedef struct
+{
+  /* Make sure total/generation is in a mostly read cacheline, while
+     awaited in a separate cacheline.  */
+  unsigned total __attribute__((aligned (64)));
+  unsigned generation;
+  unsigned awaited __attribute__((aligned (64)));
+} gomp_barrier_t;
+typedef unsigned int gomp_barrier_state_t;
+
+static inline void gomp_barrier_init (gomp_barrier_t *bar, unsigned count)
+{
+  bar->total = count;
+  bar->awaited = count;
+  bar->generation = 0;
+}
+
+static inline void gomp_barrier_reinit (gomp_barrier_t *bar, unsigned count)
+{
+  __sync_fetch_and_add (&bar->awaited, count - bar->total);
+  bar->total = count;
+}
+
+static inline void gomp_barrier_destroy (gomp_barrier_t *bar)
+{
+}
+
+extern void gomp_barrier_wait (gomp_barrier_t *);
+extern void gomp_barrier_wait_last (gomp_barrier_t *);
+extern void gomp_barrier_wait_end (gomp_barrier_t *, gomp_barrier_state_t);
+extern void gomp_team_barrier_wait (gomp_barrier_t *);
+extern void gomp_team_barrier_wait_end (gomp_barrier_t *,
+					gomp_barrier_state_t);
+extern void gomp_team_barrier_wake (gomp_barrier_t *, int);
+
+static inline gomp_barrier_state_t
+gomp_barrier_wait_start (gomp_barrier_t *bar)
+{
+  unsigned int ret = bar->generation & ~3;
+  /* Do we need any barrier here or is __sync_add_and_fetch acting
+     as the needed LoadLoad barrier already?  */
+  ret += __sync_add_and_fetch (&bar->awaited, -1) == 0;
+  return ret;
+}
+
+static inline bool
+gomp_barrier_last_thread (gomp_barrier_state_t state)
+{
+  return state & 1;
+}
+
+/* All the inlines below must be called with team->task_lock
+   held.  */
+
+static inline void
+gomp_team_barrier_set_task_pending (gomp_barrier_t *bar)
+{
+  bar->generation |= 1;
+}
+
+static inline void
+gomp_team_barrier_clear_task_pending (gomp_barrier_t *bar)
+{
+  bar->generation &= ~1;
+}
+
+static inline void
+gomp_team_barrier_set_waiting_for_tasks (gomp_barrier_t *bar)
+{
+  bar->generation |= 2;
+}
+
+static inline bool
+gomp_team_barrier_waiting_for_tasks (gomp_barrier_t *bar)
+{
+  return (bar->generation & 2) != 0;
+}
+
+static inline void
+gomp_team_barrier_done (gomp_barrier_t *bar, gomp_barrier_state_t state)
+{
+  bar->generation = (state & ~3) + 4;
+}
+
+#endif /* GOMP_BARRIER_H */