Optimize the equality check case of ICCompare stubs.

src/code-stubs.h

 // 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 98 matching lines @@
  public:
   enum Major {
 #define DEF_ENUM(name) name,
     CODE_STUB_LIST(DEF_ENUM)
 #undef DEF_ENUM
     NoCache,  // marker for stubs that do custom caching
     NUMBER_OF_IDS
   };
 
   // Retrieve the code for the stub. Generate the code if needed.
-  Handle<Code> GetCode();
+  Handle<Code> GetCode(bool use_special_cache = false);
 
   static Major MajorKeyFromKey(uint32_t key) {
     return static_cast<Major>(MajorKeyBits::decode(key));
   }
   static int MinorKeyFromKey(uint32_t key) {
     return MinorKeyBits::decode(key);
   }
 
   // Gets the major key from a code object that is a code stub or binary op IC.
   static Major GetMajorKey(Code* code_stub) {
@@ skipping 56 matching lines @@
   virtual int MinorKey() = 0;
 
   // BinaryOpStub needs to override this.
   virtual int GetCodeKind();
 
   // BinaryOpStub needs to override this.
   virtual InlineCacheState GetICState() {
     return UNINITIALIZED;
   }
 
+  // Add the code to a specialized cache, specific to an individual
+  // stub type. Please note, this method must add the code object to a
+  // roots object, otherwise we will remove the code during GC.
+  virtual bool AddToSpecialCache(Handle<Code> new_object) { return false; }
+
+  // Find code in a specialized cache, work is delegated to the specific stub.
+  virtual bool FindCodeInSpecialCache(Code** code_out) { return false; }
+
   // Returns a name for logging/debugging purposes.
   SmartArrayPointer<const char> GetName();
   virtual void PrintName(StringStream* stream);
 
   // Returns whether the code generated for this stub needs to be allocated as
   // a fixed (non-moveable) code object.
   virtual bool NeedsImmovableCode() { return false; }
 
   // Computes the key based on major and minor.
   uint32_t GetKey() {
@@ skipping 223 matching lines @@
 
 
 class ICCompareStub: public CodeStub {
  public:
   ICCompareStub(Token::Value op, CompareIC::State state)
       : op_(op), state_(state) {
     ASSERT(Token::IsCompareOp(op));
   }
 
   virtual void Generate(MacroAssembler* masm);
+  static void GenerateKnownObjects(MacroAssembler* masm, Map* map);

[Kevin Millikin (Chromium), 2011/11/10 19:08:42]

Put this down in the private section with the other Generate... functions.  Make
it non-static.  Do not pass map (== known_map_) as an argument, but instead use
known_map_ in the generate function.

[Rico, 2011/11/11 08:49:11]

Done.

+
+  void set_known_map(Map* map) { known_map_ = map; }

[Kevin Millikin (Chromium), 2011/11/10 19:08:42]

Make map a Handle<Map>.  There's a risk that a GC occurs between
set_known_map(map) and Generate().

[Rico, 2011/11/11 08:49:11]

OK, will do, but maps don't move right, and we already have handles to the
objects with the maps, so I think this should be safe even without handles

 
  private:
   class OpField: public BitField<int, 0, 3> { };
   class StateField: public BitField<int, 3, 5> { };
 
   virtual void FinishCode(Code* code) { code->set_compare_state(state_); }
 
   virtual CodeStub::Major MajorKey() { return CompareIC; }
   virtual int MinorKey();
 
   virtual int GetCodeKind() { return Code::COMPARE_IC; }
 
   void GenerateSmis(MacroAssembler* masm);
   void GenerateHeapNumbers(MacroAssembler* masm);
   void GenerateSymbols(MacroAssembler* masm);
   void GenerateStrings(MacroAssembler* masm);
   void GenerateObjects(MacroAssembler* masm);
   void GenerateMiss(MacroAssembler* masm);
 
   bool strict() const { return op_ == Token::EQ_STRICT; }
   Condition GetCondition() const { return CompareIC::ComputeCondition(op_); }
+  bool AddToSpecialCache(Handle<Code> new_object);
+  bool FindCodeInSpecialCache(Code** code_out);
 
   Token::Value op_;
   CompareIC::State state_;
+  Map* known_map_;

[Kevin Millikin (Chromium), 2011/11/10 19:08:42]

Handle<Map>.

[Rico, 2011/11/11 08:49:11]

Done.

 };
 
 
 // Flags that control the compare stub code generation.
 enum CompareFlags {
   NO_COMPARE_FLAGS = 0,
   NO_SMI_COMPARE_IN_STUB = 1 << 0,
   NO_NUMBER_COMPARE_IN_STUB = 1 << 1,
   CANT_BOTH_BE_NAN = 1 << 2
 };
@@ skipping 583 matching lines @@
   int MinorKey() { return 0; }
 
   void Generate(MacroAssembler* masm);
 
   DISALLOW_COPY_AND_ASSIGN(StoreArrayLiteralElementStub);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CODE_STUBS_H_