Parallelize marking phase of mark-sweep/compact collection cycle.

src/platform.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 95 matching lines @@
 // only when compiling with GCC versions affected by the bug (2.96.x - 4.0.x)
 // __GNUC_PREREQ is not defined in GCC for Mac OS X, so we define our own macro
 #if __GNUC_VERSION__ >= 29600 && __GNUC_VERSION__ < 40100
 #include <limits>
 #undef V8_INFINITY
 #define V8_INFINITY std::numeric_limits<double>::infinity()
 #endif
 
 #endif  // __GNUC__
 
+#include "atomic.h"
+
 namespace v8 {
 namespace internal {
 
 // Use AtomicWord for a machine-sized pointer. It is assumed that
 // reads and writes of naturally aligned values of this type are atomic.
 typedef intptr_t AtomicWord;
 
 class Semaphore;
 
 double ceiling(double x);
@@ skipping 451 matching lines @@
   bool active_;
   PlatformData* data_;  // Platform specific data.
   DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler);
 };
 
 #endif  // ENABLE_LOGGING_AND_PROFILING
 
 } }  // namespace v8::internal
 
 #endif  // V8_PLATFORM_H_