Make some constants' meaning clear for X64

src/x64/assembler-x64-inl.h

 // Copyright 2012 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 355 matching lines @@
     // TODO(1550) We are passing NULL as a slot because cell can never be on
     // evacuation candidate.
     host()->GetHeap()->incremental_marking()->RecordWrite(
         host(), NULL, cell);
   }
 }
 
 
 bool RelocInfo::IsPatchedReturnSequence() {
   // The recognized call sequence is:
-  //  movq(kScratchRegister, immediate64); call(kScratchRegister);
+  //  movq(kScratchRegister, address); call(kScratchRegister);
   // It only needs to be distinguished from a return sequence
   //  movq(rsp, rbp); pop(rbp); ret(n); int3 *6
   // The 11th byte is int3 (0xCC) in the return sequence and
   // REX.WB (0x48+register bit) for the call sequence.
 #ifdef ENABLE_DEBUGGER_SUPPORT
-  return pc_[2 + kPointerSize] != 0xCC;
+  return pc_[Assembler::kMoveAddressIntoScratchRegisterInstructionLength] !=
+         0xCC;
 #else
   return false;
 #endif
 }
 
 
 bool RelocInfo::IsPatchedDebugBreakSlotSequence() {
   return !Assembler::IsNop(pc());
 }
 
@@ skipping 146 matching lines @@
   ASSERT(len_ == 1 || len_ == 2);
   int32_t* p = reinterpret_cast<int32_t*>(&buf_[len_]);
   *p = disp;
   len_ += sizeof(int32_t);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_ASSEMBLER_X64_INL_H_