Add thread-safety to creation of MemCopy and modulo functions.

src/platform.h

-// Copyright 2006-2008 the V8 project authors. All rights reserved.
+// Copyright 2011 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
 //       with the distribution.
@@ skipping 284 matching lines @@
 
   // Support runtime detection of FPU on MIPS CPUs.
   static bool MipsCpuHasFeature(CpuFeature feature);
 
   // Returns the activation frame alignment constraint or zero if
   // the platform doesn't care. Guaranteed to be a power of two.
   static int ActivationFrameAlignment();
 
   static void ReleaseStore(volatile AtomicWord* ptr, AtomicWord value);
 
+#if defined(V8_TARGET_ARCH_IA32)
+  // Copy memory area to disjoint memory area.
+  static void MemCopy(void* dest, const void* src, size_t size);
+  // Limit below which the extra overhead of the MemCopy function is likely
+  // to outweigh the benefits of faster copying.
+  static const int kMinComplexMemCopy = 64;
+  typedef void (*MemCopyFunction)(void* dest, const void* src, size_t size);
+
+#else  // V8_TARGET_ARCH_IA32
+  static void MemCopy(void* dest, const void* src, size_t size) {
+    memcpy(dest, src, size);
+  }
+  static const int kMinComplexMemCopy = 256;
+#endif  // V8_TARGET_ARCH_IA32
+
  private:
   static const int msPerSecond = 1000;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(OS);
 };
 
 
 class VirtualMemory {
  public:
   // Reserves virtual memory with size.
@@ skipping 352 matching lines @@
   int samples_taken_;  // Counts stack samples taken.
   DISALLOW_IMPLICIT_CONSTRUCTORS(Sampler);
 };
 
 
 #endif  // ENABLE_LOGGING_AND_PROFILING
 
 } }  // namespace v8::internal
 
 #endif  // V8_PLATFORM_H_