X64: Fix bugs affecting Win64.

src/platform-win32.cc

 // 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 1776 matching lines @@
     // Loop until the sampler is disengaged.
     while (sampler_->IsActive()) {
       TickSample sample;
 
       // If profiling, we record the pc and sp of the profiled thread.
       if (sampler_->IsProfiling()
           && SuspendThread(profiled_thread_) != (DWORD)-1) {
         context.ContextFlags = CONTEXT_FULL;
         if (GetThreadContext(profiled_thread_, &context) != 0) {
 #if V8_HOST_ARCH_X64
-          UNIMPLEMENTED();
           sample.pc = context.Rip;
           sample.sp = context.Rsp;
           sample.fp = context.Rbp;
 #else
           sample.pc = context.Eip;
           sample.sp = context.Esp;
           sample.fp = context.Ebp;
 #endif
           sampler_->SampleStack(&sample);
         }
@@ skipping 73 matching lines @@
 
   // Release the thread handles
   CloseHandle(data_->sampler_thread_);
   CloseHandle(data_->profiled_thread_);
 }
 
 
 #endif  // ENABLE_LOGGING_AND_PROFILING
 
 } }  // namespace v8::internal