From 82bcbebce43f0227f506d75a5b764b6847041bae Mon Sep 17 00:00:00 2001
From: Ben Cheng <bccheng@google.com>
Date: Mon, 1 Oct 2012 10:30:31 -0700
Subject: Initial check-in of gcc 4.7.2.

Change-Id: I4a2f5a921c21741a0e18bda986d77e5f1bef0365
---
 gcc-4.7/libitm/stmlock.h | 122 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 gcc-4.7/libitm/stmlock.h

(limited to 'gcc-4.7/libitm/stmlock.h')

diff --git a/gcc-4.7/libitm/stmlock.h b/gcc-4.7/libitm/stmlock.h
new file mode 100644
index 000000000..a338258e9
--- /dev/null
+++ b/gcc-4.7/libitm/stmlock.h
@@ -0,0 +1,122 @@
+/* Copyright (C) 2009, 2011 Free Software Foundation, Inc.
+   Contributed by Richard Henderson <rth@redhat.com>.
+
+   This file is part of the GNU Transactional Memory Library (libitm).
+
+   Libitm 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 of the License, or
+   (at your option) any later version.
+
+   Libitm 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/>.  */
+
+#ifndef LIBITM_STMLOCK_H
+#define LIBITM_STMLOCK_H 1
+
+namespace GTM HIDDEN {
+
+/* A versioned write lock on a cacheline.  This must be wide enough to
+   store a pointer, and preferably wide enough to avoid overflowing the
+   version counter.  Thus we use a "word", which should be 64-bits on
+   64-bit systems even when their pointer size is forced smaller.  */
+typedef gtm_word gtm_stmlock;
+
+/* This has to be the same size as gtm_stmlock, we just use this name
+   for documentation purposes.  */
+typedef gtm_word gtm_version;
+
+/* The maximum value a version number can have.  This is a consequence
+   of having the low bit of gtm_stmlock reserved for the owned bit.  */
+#define GTM_VERSION_MAX		(~(gtm_version)0 >> 1)
+
+/* A value that may be used to indicate "uninitialized" for a version.  */
+#define GTM_VERSION_INVALID	(~(gtm_version)0)
+
+/* This bit is set when the write lock is held.  When set, the balance of
+   the bits in the lock is a pointer that references STM backend specific
+   data; it is up to the STM backend to determine if this thread holds the
+   lock.  If this bit is clear, the balance of the bits are the last
+   version number committed to the cacheline.  */
+static inline bool
+gtm_stmlock_owned_p (gtm_stmlock lock)
+{
+  return lock & 1;
+}
+
+static inline gtm_stmlock
+gtm_stmlock_set_owned (void *data)
+{
+  return (gtm_stmlock)(uintptr_t)data | 1;
+}
+
+static inline void *
+gtm_stmlock_get_addr (gtm_stmlock lock)
+{
+  return (void *)((uintptr_t)lock & ~(uintptr_t)1);
+}
+
+static inline gtm_version
+gtm_stmlock_get_version (gtm_stmlock lock)
+{
+  return lock >> 1;
+}
+
+static inline gtm_stmlock
+gtm_stmlock_set_version (gtm_version ver)
+{
+  return ver << 1;
+}
+
+/* We use a fixed set of locks for all memory, hashed into the
+   following table.  */
+#define LOCK_ARRAY_SIZE  (1024 * 1024)
+extern gtm_stmlock gtm_stmlock_array[LOCK_ARRAY_SIZE];
+
+static inline gtm_stmlock *
+gtm_get_stmlock (const gtm_cacheline *addr)
+{
+  size_t idx = ((uintptr_t) addr / CACHELINE_SIZE) % LOCK_ARRAY_SIZE;
+  return gtm_stmlock_array + idx;
+}
+
+/* The current global version number.  */
+extern atomic<gtm_version> gtm_clock;
+
+static inline gtm_version
+gtm_get_clock (void)
+{
+  atomic_thread_fence(memory_order_release);
+  return gtm_clock.load(memory_order_acquire);
+}
+
+static inline gtm_version
+gtm_inc_clock (void)
+{
+  /* ??? Here we have a choice, the pre-inc operator mapping to
+     __atomic_add_fetch with memory_order_seq_cst, or fetch_add
+     with memory_order_acq_rel plus another separate increment.
+     We really ought to recognize and optimize fetch_op(x) op x... */
+  gtm_version r = ++gtm_clock;
+
+  /* ??? Ought to handle wraparound for 32-bit.  */
+  if (sizeof(r) < 8 && r > GTM_VERSION_MAX)
+    abort ();
+
+  return r;
+}
+
+} // namespace GTM
+
+#endif // LIBITM_STMLOCK_H
-- 
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