[hydrogen] optimize switch with string clauses

src/ast.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 692 matching lines @@
 
   int position() const { return position_; }
   void set_position(int pos) { position_ = pos; }
 
   int EntryId() { return entry_id_; }
   int CompareId() { return compare_id_; }
 
   // Type feedback information.
   void RecordTypeFeedback(TypeFeedbackOracle* oracle);
   bool IsSmiCompare() { return compare_type_ == SMI_ONLY; }
+  bool IsSymbolCompare() { return compare_type_ == SYMBOL_ONLY; }

[fschneider, 2011/11/01 09:26:19]

You introduce IsSymbolCompare, but it does not seem to be used anywhere. Can you
use it in the same way we use the type feedback for smis?

[indutny, 2011/11/01 09:31:07]

Probably, better remove it, as I can't see any use for it in current version of
code (because of oddball checks)

   bool IsObjectCompare() { return compare_type_ == OBJECT_ONLY; }
 
  private:
   Expression* label_;
   Label body_target_;
   ZoneList<Statement*>* statements_;
   int position_;
-  enum CompareTypeFeedback { NONE, SMI_ONLY, OBJECT_ONLY };
+  enum CompareTypeFeedback { NONE, SMI_ONLY, SYMBOL_ONLY, OBJECT_ONLY };
   CompareTypeFeedback compare_type_;
   int compare_id_;
   int entry_id_;
 };
 
 
 class SwitchStatement: public BreakableStatement {
  public:
   inline SwitchStatement(Isolate* isolate, ZoneStringList* labels);
 
@@ skipping 1393 matching lines @@
 
  private:
   Isolate* isolate_;
   bool stack_overflow_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_AST_H_