1 files changed, 69 insertions, 0 deletions
diff --git a/gcc-4.9/libgomp/config/linux/mutex.c b/gcc-4.9/libgomp/config/linux/mutex.c
new file mode 100644
index 000000000..cd93cd27c
--- /dev/null
+++ b/gcc-4.9/libgomp/config/linux/mutex.c
@@ -0,0 +1,69 @@
+/* Copyright (C) 2005-2014 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 mutex synchronization
+   mechanism for libgomp.  This type is private to the library.  This
+   implementation uses atomic instructions and the futex syscall.  */
+
+#include "wait.h"
+
+long int gomp_futex_wake = FUTEX_WAKE | FUTEX_PRIVATE_FLAG;
+long int gomp_futex_wait = FUTEX_WAIT | FUTEX_PRIVATE_FLAG;
+
+void
+gomp_mutex_lock_slow (gomp_mutex_t *mutex, int oldval)
+{
+  /* First loop spins a while.  */
+  while (oldval == 1)
+    {
+      if (do_spin (mutex, 1))
+	{
+	  /* Spin timeout, nothing changed.  Set waiting flag.  */
+	  oldval = __atomic_exchange_n (mutex, -1, MEMMODEL_ACQUIRE);
+	  if (oldval == 0)
+	    return;
+	  futex_wait (mutex, -1);
+	  break;
+	}
+      else
+	{
+	  /* Something changed.  If now unlocked, we're good to go.  */
+	  oldval = 0;
+	  if (__atomic_compare_exchange_n (mutex, &oldval, 1, false,
+					   MEMMODEL_ACQUIRE, MEMMODEL_RELAXED))
+	    return;
+	}
+    }
+
+  /* Second loop waits until mutex is unlocked.  We always exit this
+     loop with wait flag set, so next unlock will awaken a thread.  */
+  while ((oldval = __atomic_exchange_n (mutex, -1, MEMMODEL_ACQUIRE)))
+    do_wait (mutex, -1);
+}
+
+void
+gomp_mutex_unlock_slow (gomp_mutex_t *mutex)
+{
+  futex_wake (mutex, 1);
+}