Refactor lithium classes to reduce the number of virtual functions.

src/arm/lithium-arm.cc

 // Copyright 2011 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 132 matching lines @@
   for (int i = 0; i < 4; i++) {
     if (parallel_moves_[i] != NULL && !parallel_moves_[i]->IsRedundant()) {
       return false;
     }
   }
 
   return true;
 }
 
 
-void LGap::PrintDataTo(StringStream* stream) const {
+void LGap::PrintDataTo(StringStream* stream) {
   for (int i = 0; i < 4; i++) {
     stream->Add("(");
     if (parallel_moves_[i] != NULL) {
       parallel_moves_[i]->PrintDataTo(stream);
     }
     stream->Add(") ");
   }
 }
 
 
@@ skipping 284 matching lines @@
         if (can_eliminate) {
           label->set_replacement(GetLabel(goto_instr->block_id()));
         }
       }
     }
   }
 }
 
 
 void LChunk::AddInstruction(LInstruction* instr, HBasicBlock* block) {
-  LGap* gap = new LGap(block);
+  LInstructionGap* gap = new LInstructionGap(block);
   int index = -1;
   if (instr->IsControl()) {
     instructions_.Add(gap);
     index = instructions_.length();
     instructions_.Add(instr);
   } else {
     index = instructions_.length();
     instructions_.Add(instr);
     instructions_.Add(gap);
   }
@@ skipping 1667 matching lines @@
 
 
 LInstruction* LChunkBuilder::DoLeaveInlined(HLeaveInlined* instr) {
   HEnvironment* outer = current_block_->last_environment()->outer();
   current_block_->UpdateEnvironment(outer);
   return NULL;
 }
 
 
 } }  // namespace v8::internal