Fast elements conversions in crankshaft using generated code.

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 1012 matching lines @@
                     bool result);
   void GenerateTypeTransition(MacroAssembler* masm);
 
   Register tos_;
   Types types_;
 };
 
 
 class FastElementsConversionStub : public CodeStub {
  public:
+  enum Type {
+    TRANSITION_ONLY,
+    TRANSITION_AND_STORE
+  };
+
   FastElementsConversionStub(ElementsKind from,
                              ElementsKind to,
                              bool is_jsarray,
                              StrictModeFlag strict_mode)
       : from_(from),
         to_(to),
         is_jsarray_(is_jsarray),
         strict_mode_(strict_mode) {}
 
+  static void GenerateSmiOnlyToDouble(
+      MacroAssembler* masm,
+      Type type,
+      StrictModeFlag strict_mode = kInvalidStrictFlag);
+
+  static void GenerateDoubleToObject(
+      MacroAssembler* masm,
+      Type type,
+      StrictModeFlag strict_mode = kInvalidStrictFlag);
+
  private:
-  class FromBits:       public BitField<ElementsKind,    0, 8> {};
+  class FromBits:       public BitField<ElementsKind,    0, 4> {};

[Jakob Kummerow, 2011/10/19 18:36:31]

why this change? (I'm not saying it's bad; it's just surprising that you've
changed one ElementsKind bit field and not the other.)

   class ToBits:         public BitField<ElementsKind,    8, 8> {};
   class IsJSArrayBits:  public BitField<bool,           16, 8> {};
   class StrictModeBits: public BitField<StrictModeFlag, 24, 8> {};
 
   Major MajorKey() { return FastElementsConversion; }
   int MinorKey() {
     return FromBits::encode(from_) |
         ToBits::encode(to_) |
         IsJSArrayBits::encode(is_jsarray_) |
         StrictModeBits::encode(strict_mode_);
   }
 
   void Generate(MacroAssembler* masm);
+
   static void GenerateSmiOnlyToObject(MacroAssembler* masm);
-  static void GenerateSmiOnlyToDouble(MacroAssembler* masm,
-                                      StrictModeFlag strict_mode);
-  static void GenerateDoubleToObject(MacroAssembler* masm,
-                                     StrictModeFlag strict_mode);
 
   ElementsKind from_;
   ElementsKind to_;
   bool is_jsarray_;
   StrictModeFlag strict_mode_;
 
   DISALLOW_COPY_AND_ASSIGN(FastElementsConversionStub);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CODE_STUBS_H_