Various improvements regarding the way we print code code comments.

src/arm/lithium-arm.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 264 matching lines @@
 
   // Interface to the register allocator and iterators.
   bool IsMarkedAsCall() const { return is_call_; }
 
   virtual bool HasResult() const = 0;
   virtual LOperand* result() = 0;
 
   LOperand* FirstInput() { return InputAt(0); }
   LOperand* Output() { return HasResult() ? result() : NULL; }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return true; }
+
 #ifdef DEBUG
   void VerifyCall();
 #endif
 
  private:
   // Iterator support.
   friend class InputIterator;
   virtual int InputCount() = 0;
   virtual LOperand* InputAt(int i) = 0;
 
@@ skipping 79 matching lines @@
  private:
   LParallelMove* parallel_moves_[LAST_INNER_POSITION + 1];
   HBasicBlock* block_;
 };
 
 
 class LInstructionGap: public LGap {
  public:
   explicit LInstructionGap(HBasicBlock* block) : LGap(block) { }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const {
+    return !IsRedundant();
+  }
+
   DECLARE_CONCRETE_INSTRUCTION(InstructionGap, "gap")
 };
 
 
 class LGoto: public LTemplateInstruction<0, 0, 0> {
  public:
   explicit LGoto(int block_id) : block_id_(block_id) { }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const;
   DECLARE_CONCRETE_INSTRUCTION(Goto, "goto")
   virtual void PrintDataTo(StringStream* stream);
   virtual bool IsControl() const { return true; }
 
   int block_id() const { return block_id_; }
 
  private:
   int block_id_;
 };
 
@@ skipping 27 matching lines @@
  public:
   DECLARE_CONCRETE_INSTRUCTION(Deoptimize, "deoptimize")
 };
 
 
 class LLabel: public LGap {
  public:
   explicit LLabel(HBasicBlock* block)
       : LGap(block), replacement_(NULL) { }
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(Label, "label")
 
   virtual void PrintDataTo(StringStream* stream);
 
   int block_id() const { return block()->block_id(); }
   bool is_loop_header() const { return block()->IsLoopHeader(); }
+  bool is_osr_entry() const { return block()->is_osr_entry(); }
   Label* label() { return &label_; }
   LLabel* replacement() const { return replacement_; }
   void set_replacement(LLabel* label) { replacement_ = label; }
   bool HasReplacement() const { return replacement_ != NULL; }
 
  private:
   Label label_;
   LLabel* replacement_;
 };
 
 
 class LParameter: public LTemplateInstruction<1, 0, 0> {
  public:
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(Parameter, "parameter")
 };
 
 
 class LCallStub: public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(CallStub, "call-stub")
   DECLARE_HYDROGEN_ACCESSOR(CallStub)
 
   TranscendentalCache::Type transcendental_type() {
     return hydrogen()->transcendental_type();
   }
 };
 
 
 class LUnknownOSRValue: public LTemplateInstruction<1, 0, 0> {
  public:
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(UnknownOSRValue, "unknown-osr-value")
 };
 
 
 template<int I, int T>
 class LControlInstruction: public LTemplateInstruction<0, I, T> {
  public:
   virtual bool IsControl() const { return true; }
 
   int SuccessorCount() { return hydrogen()->SuccessorCount(); }
@@ skipping 2074 matching lines @@
   LOperand* key() { return inputs_[1]; }
 
   DECLARE_CONCRETE_INSTRUCTION(DeleteProperty, "delete-property")
 };
 
 
 class LOsrEntry: public LTemplateInstruction<0, 0, 0> {
  public:
   LOsrEntry();
 
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
   DECLARE_CONCRETE_INSTRUCTION(OsrEntry, "osr-entry")
 
   LOperand** SpilledRegisterArray() { return register_spills_; }
   LOperand** SpilledDoubleRegisterArray() { return double_register_spills_; }
 
   void MarkSpilledRegister(int allocation_index, LOperand* spill_operand);
   void MarkSpilledDoubleRegister(int allocation_index,
                                  LOperand* spill_operand);
 
  private:
@@ skipping 268 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_LITHIUM_ARM_H_