Perform string add in generated code on IA-32 platforms...

src/ia32/codegen-ia32.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
 //       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 528 matching lines @@
 
   // Fast support for Math.random().
   void GenerateRandomPositiveSmi(ZoneList<Expression*>* args);
 
   // Fast support for Math.sin and Math.cos.
   enum MathOp { SIN, COS };
   void GenerateFastMathOp(MathOp op, ZoneList<Expression*>* args);
   inline void GenerateMathSin(ZoneList<Expression*>* args);
   inline void GenerateMathCos(ZoneList<Expression*>* args);
 
+  // Fast support for StringAdd.
+  void GenerateStringAdd(ZoneList<Expression*>* args);
+
   // Simple condition analysis.
   enum ConditionAnalysis {
     ALWAYS_TRUE,
     ALWAYS_FALSE,
     DONT_KNOW
   };
   ConditionAnalysis AnalyzeCondition(Expression* cond);
 
   // Methods used to indicate which source code is generated for. Source
   // positions are collected by the assembler and emitted with the relocation
@@ skipping 171 matching lines @@
   }
 
   void SetArgsInRegisters() { args_in_registers_ = true; }
   void SetArgsReversed() { args_reversed_ = true; }
   bool HasSmiCodeInStub() { return (flags_ & NO_SMI_CODE_IN_STUB) == 0; }
   bool HasArgumentsInRegisters() { return args_in_registers_; }
   bool HasArgumentsReversed() { return args_reversed_; }
 };
 
 
+// Flag that indicates how to generate code for the stub StringAddStub.
+enum StringAddFlags {
+  NO_STRING_ADD_FLAGS = 0,
+  NO_STRING_CHECK_IN_STUB = 1 << 0  // Omit string check in stub.
+};
+
+
+class StringAddStub: public CodeStub {
+ public:
+  explicit StringAddStub(StringAddFlags flags) {
+    string_check_ = ((flags & NO_STRING_CHECK_IN_STUB) == 0);
+  }
+
+ private:
+  Major MajorKey() { return StringAdd; }
+  int MinorKey() { return string_check_ ? 0 : 1; }
+
+  void Generate(MacroAssembler* masm);
+
+  void GenerateCopyCharacters(MacroAssembler* masm,
+                                   Register desc,
+                                   Register src,
+                                   Register count,
+                                   Register scratch,
+                                   bool ascii);
+
+  // Should the stub check whether arguments are strings?
+  bool string_check_;
+};
+
+
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_CODEGEN_IA32_H_