Minor cleanup of CompareIC state

src/ic.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 691 matching lines @@
 };
 
 
 class UnaryOpIC: public IC {
  public:
   // sorted: increasingly more unspecific (ignoring UNINITIALIZED)
   // TODO(svenpanne) Using enums+switch is an antipattern, use a class instead.
   enum TypeInfo {
     UNINITIALIZED,
     SMI,
-    HEAP_NUMBER,
+    NUMBER,
     GENERIC
   };
 
   explicit UnaryOpIC(Isolate* isolate) : IC(NO_EXTRA_FRAME, isolate) { }
 
   void patch(Code* code);
 
   static const char* GetName(TypeInfo type_info);
 
   static State ToState(TypeInfo type_info);
 
   static TypeInfo GetTypeInfo(Handle<Object> operand);
 
   static TypeInfo ComputeNewType(TypeInfo type, TypeInfo previous);
 };
 
 
 // Type Recording BinaryOpIC, that records the types of the inputs and outputs.
 class BinaryOpIC: public IC {
  public:
   enum TypeInfo {
     UNINITIALIZED,
     SMI,
     INT32,
-    HEAP_NUMBER,
+    NUMBER,
     ODDBALL,
     STRING,  // Only used for addition operation.
     GENERIC
   };
 
   explicit BinaryOpIC(Isolate* isolate) : IC(NO_EXTRA_FRAME, isolate) { }
 
   void patch(Code* code);
 
   static const char* GetName(TypeInfo type_info);
 
   static State ToState(TypeInfo type_info);
 };
 
 
 class CompareIC: public IC {
  public:
+  // The type/state lattice is defined by the following inequations:
+  //   UNINITIALIZED < ...
+  //   ... < GENERIC
+  //   SMI < NUMBER
+  //   SYMBOL < STRING
+  //   KNOWN_OBJECT < OBJECT
   enum State {
     UNINITIALIZED,
     SMI,
-    HEAP_NUMBER,
+    NUMBER,
     SYMBOL,
     STRING,
-    OBJECT,
-    KNOWN_OBJECTS,
+    OBJECT,         // JSObject
+    KNOWN_OBJECT,   // JSObject with specific map (faster check)
     GENERIC
   };
 
   CompareIC(Isolate* isolate, Token::Value op)
       : IC(EXTRA_CALL_FRAME, isolate), op_(op) { }
 
   // Update the inline cache for the given operands.
   void UpdateCaches(Handle<Object> x, Handle<Object> y);
 
 
@@ skipping 39 matching lines @@
 // Helper for BinaryOpIC and CompareIC.
 enum InlinedSmiCheck { ENABLE_INLINED_SMI_CHECK, DISABLE_INLINED_SMI_CHECK };
 void PatchInlinedSmiCode(Address address, InlinedSmiCheck check);
 
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, KeyedLoadIC_Miss);
 DECLARE_RUNTIME_FUNCTION(MaybeObject*, KeyedLoadIC_MissFromStubFailure);
 
 } }  // namespace v8::internal
 
 #endif  // V8_IC_H_