[interpreter] Add output register to ToName

src/interpreter/mkpeephole.cc

 // Copyright 2016 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 <array>
 #include <fstream>
 #include <map>
 #include <string>
 #include <vector>
 
@@ skipping 88 matching lines @@
         return {PeepholeAction::kTransformLdaStarToLdrLdarAction,
                 Bytecode::kLdrContextSlot};
       case Bytecode::kLdaUndefined:
         return {PeepholeAction::kTransformLdaStarToLdrLdarAction,
                 Bytecode::kLdrUndefined};
       default:
         break;
     }
   }
 
-  // ToName optimizations: remove unnecessary ToName bytecodes.
+  // ToName bytecodes can be replaced by Star with the same output register if
+  // the value in the accumulator is already a name.
   if (current == Bytecode::kToName) {
     if (last == Bytecode::kLdaConstant) {
-      return {PeepholeAction::kElideCurrentIfLoadingNameConstantAction,
+      return {PeepholeAction::kTransformToStarIfLoadingNameConstantAction,
               Bytecode::kIllegal};
     } else if (Bytecodes::PutsNameInAccumulator(last)) {
-      return {PeepholeAction::kElideCurrentAction, Bytecode::kIllegal};
+      return {PeepholeAction::kChangeBytecodeAction, Bytecode::kStar};
     }
   }
 
   // Nop are placeholders for holding source position information and can be
   // elided if there is no source information.
   if (last == Bytecode::kNop) {
     if (Bytecodes::IsJump(current)) {
       return {PeepholeAction::kElideLastBeforeJumpAction, Bytecode::kIllegal};
     } else {
       return {PeepholeAction::kElideLastAction, Bytecode::kIllegal};
@@ skipping 252 matching lines @@
 
   std::ofstream ofs(argv[1], std::ofstream::trunc);
   v8::internal::interpreter::PeepholeActionTableWriter writer;
   writer.BuildTable();
   writer.Write(ofs);
   ofs.flush();
   ofs.close();
 
   return 0;
 }