Revert of Remove register index/code indirection

src/arm64/lithium-arm64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/arm64/lithium-arm64.h"
 
 #include <sstream>
 
 #include "src/arm64/lithium-codegen-arm64.h"
 #include "src/hydrogen-osr.h"
@@ skipping 357 matching lines @@
     case Token::SAR: return "sar-t";
     case Token::SHR: return "shr-t";
     default:
       UNREACHABLE();
       return NULL;
   }
 }
 
 
 LUnallocated* LChunkBuilder::ToUnallocated(Register reg) {
-  return new (zone()) LUnallocated(LUnallocated::FIXED_REGISTER, reg.code());
+  return new(zone()) LUnallocated(LUnallocated::FIXED_REGISTER,
+                                  Register::ToAllocationIndex(reg));
 }
 
 
 LUnallocated* LChunkBuilder::ToUnallocated(DoubleRegister reg) {
-  return new (zone())
-      LUnallocated(LUnallocated::FIXED_DOUBLE_REGISTER, reg.code());
+  return new(zone()) LUnallocated(LUnallocated::FIXED_DOUBLE_REGISTER,
+                                  DoubleRegister::ToAllocationIndex(reg));
 }
 
 
 LOperand* LChunkBuilder::Use(HValue* value, LUnallocated* operand) {
   if (value->EmitAtUses()) {
     HInstruction* instr = HInstruction::cast(value);
     VisitInstruction(instr);
   }
   operand->set_virtual_register(value->id());
   return operand;
@@ skipping 2392 matching lines @@
   LOperand* context = UseFixed(instr->context(), cp);
   LOperand* function = UseRegisterAtStart(instr->function());
   LAllocateBlockContext* result =
       new(zone()) LAllocateBlockContext(context, function);
   return MarkAsCall(DefineFixed(result, cp), instr);
 }
 
 
 }  // namespace internal
 }  // namespace v8