Improved code for megamorphic stub on ia32.

src/stub-cache.h

 // Copyright 2006-2008 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
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@@ skipping 178 matching lines @@
 
   // Update cache for entry hash(name, map).
   static Code* Set(String* name, Map* map, Code* code);
 
   // Clear the lookup table (@ mark compact collection).
   static void Clear();
 
   // Functions for generating stubs at startup.
   static void GenerateMiss(MacroAssembler* masm);
 
   // Generate code for probing the stub cache table.

[Kasper Lund, 2009/07/02 12:53:08]

I think you should add a note about the contract here. Both scratch and extra
will be clobbered, but it's okay to pass in no_reg for extra... or something
like that.

   static void GenerateProbe(MacroAssembler* masm,
                             Code::Flags flags,
                             Register receiver,
                             Register name,
-                            Register scratch);
+                            Register scratch,
+                            Register extra);

[Kasper Lund, 2009/07/02 12:53:08]

Will this change break the compilation of all non-IA32 platforms?

 
   enum Table {
     kPrimary,
     kSecondary
   };
 
  private:
   friend class SCTableReference;
   static const int kPrimaryTableSize = 2048;
   static const int kSecondaryTableSize = 512;
@@ skipping 313 matching lines @@
 
   const ParameterCount& arguments() { return arguments_; }
 
   Object* GetCode(PropertyType type, String* name);
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_STUB_CACHE_H_