Tentative implementation of string slices (hidden under the flag --string-slices).

src/x64/lithium-x64.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 1665 matching lines @@
   }
 
   DECLARE_CONCRETE_INSTRUCTION(StringAdd, "string-add")
   DECLARE_HYDROGEN_ACCESSOR(StringAdd)
 
   LOperand* left() { return inputs_[0]; }
   LOperand* right() { return inputs_[1]; }
 };
 
 
-class LStringCharCodeAt: public LTemplateInstruction<1, 2, 0> {
+class LStringCharCodeAt: public LTemplateInstruction<1, 2, 1> {
  public:
-  LStringCharCodeAt(LOperand* string, LOperand* index) {
+  LStringCharCodeAt(LOperand* string, LOperand* index, LOperand* temp) {
     inputs_[0] = string;
     inputs_[1] = index;
+    temps_[0] = temp;
   }
 
   DECLARE_CONCRETE_INSTRUCTION(StringCharCodeAt, "string-char-code-at")
   DECLARE_HYDROGEN_ACCESSOR(StringCharCodeAt)
 
   LOperand* string() { return inputs_[0]; }
   LOperand* index() { return inputs_[1]; }
 };
 
 
@@ skipping 479 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::int
 
 #endif  // V8_X64_LITHIUM_X64_H_