Revert of Remove register index/code indirection

src/mips/lithium-mips.cc

 // Copyright 2012 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/mips/lithium-mips.h"
 
 #include <sstream>
 
 #if V8_TARGET_ARCH_MIPS
 
@@ skipping 433 matching lines @@
     if (i < blocks->length() - 1) next = blocks->at(i + 1);
     DoBasicBlock(blocks->at(i), next);
     if (is_aborted()) return NULL;
   }
   status_ = DONE;
   return chunk_;
 }
 
 
 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::UseFixed(HValue* value, Register fixed_register) {
   return Use(value, ToUnallocated(fixed_register));
 }
 
 
 LOperand* LChunkBuilder::UseFixedDouble(HValue* value, DoubleRegister reg) {
   return Use(value, ToUnallocated(reg));
@@ skipping 2170 matching lines @@
   LOperand* function = UseRegisterAtStart(instr->function());
   LAllocateBlockContext* result =
       new(zone()) LAllocateBlockContext(context, function);
   return MarkAsCall(DefineFixed(result, cp), instr);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS