X64 implementation starts using virtual frame and register allocators.

src/x64/register-allocator-x64-inl.h

 // Copyright 2009 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 19 matching lines @@
 
 #include "v8.h"
 
 namespace v8 {
 namespace internal {
 
 // -------------------------------------------------------------------------
 // RegisterAllocator implementation.
 
 bool RegisterAllocator::IsReserved(Register reg) {
-  // All registers are reserved for now.
-  return true;
+  return reg.is(rsp) || reg.is(rbp) || reg.is(rsi) || reg.is(r10);
 }
 
 
 // The register allocator uses small integers to represent the
 // non-reserved assembler registers.
 
 int RegisterAllocator::ToNumber(Register reg) {
   ASSERT(reg.is_valid() && !IsReserved(reg));
-  UNIMPLEMENTED();
-  return -1;
+  return reg.code();
 }
 
 
 Register RegisterAllocator::ToRegister(int num) {
   ASSERT(num >= 0 && num < kNumRegisters);
-  UNIMPLEMENTED();
-  return no_reg;
+  Register result = {num};
+  return result;
 }
 
 
 void RegisterAllocator::Initialize() {
-  UNIMPLEMENTED();
+  // TODO(X64): Implement.
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_REGISTER_ALLOCATOR_X64_INL_H_