Added regexp-re2 library to external.
Change-Id: I54e60045f0fee91b64e4d7291e5bb6c6cffb4562
diff --git a/util/atomicops.h b/util/atomicops.h
new file mode 100644
index 0000000..11c1196
--- /dev/null
+++ b/util/atomicops.h
@@ -0,0 +1,79 @@
+// Copyright 2006-2008 The RE2 Authors. All Rights Reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#ifndef RE2_UTIL_ATOMICOPS_H__
+#define RE2_UTIL_ATOMICOPS_H__
+
+#if defined(__i386__)
+
+static inline void WriteMemoryBarrier() {
+ int x;
+ __asm__ __volatile__("xchgl (%0),%0" // The lock prefix is implicit for xchg.
+ :: "r" (&x));
+}
+
+#elif defined(__x86_64__)
+
+// 64-bit implementations of memory barrier can be simpler, because
+// "sfence" is guaranteed to exist.
+static inline void WriteMemoryBarrier() {
+ __asm__ __volatile__("sfence" : : : "memory");
+}
+
+#elif defined(__ppc__)
+
+static inline void WriteMemoryBarrier() {
+ __asm__ __volatile__("eieio" : : : "memory");
+}
+
+#elif defined(__alpha__)
+
+static inline void WriteMemoryBarrier() {
+ __asm__ __volatile__("wmb" : : : "memory");
+}
+
+#else
+
+#include "util/mutex.h"
+
+static inline void WriteMemoryBarrier() {
+ // Slight overkill, but good enough:
+ // any mutex implementation must have
+ // a read barrier after the lock operation and
+ // a write barrier before the unlock operation.
+ //
+ // It may be worthwhile to write architecture-specific
+ // barriers for the common platforms, as above, but
+ // this is a correct fallback.
+ re2::Mutex mu;
+ re2::MutexLock l(&mu);
+}
+
+/*
+#error Need WriteMemoryBarrier for architecture.
+
+// Windows
+inline void WriteMemoryBarrier() {
+ LONG x;
+ ::InterlockedExchange(&x, 0);
+}
+*/
+
+#endif
+
+// Alpha has very weak memory ordering. If relying on WriteBarriers, must one
+// use read barriers for the readers too.
+#if defined(__alpha__)
+
+static inline void MaybeReadMemoryBarrier() {
+ __asm__ __volatile__("mb" : : : "memory");
+}
+
+#else
+
+static inline void MaybeReadMemoryBarrier() {}
+
+#endif // __alpha__
+
+#endif // RE2_UTIL_ATOMICOPS_H__