Implemented one-char cache lookup in generated code.

src/string.js

 // Copyright 2006-2009 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 51 matching lines @@
 
 // ECMA-262, section 15.5.4.4
 function StringCharAt(pos) {
   var char_code = %_FastCharCodeAt(this, pos);
   if (!%_IsSmi(char_code)) {
     var subject = TO_STRING_INLINE(this);
     var index = TO_INTEGER(pos);
     if (index >= subject.length || index < 0) return "";
     char_code = %StringCharCodeAt(subject, index);
   }
-  return %CharFromCode(char_code);
+  return %_CharFromCode(char_code);
 }
 
 
 // ECMA-262 section 15.5.4.5
 function StringCharCodeAt(pos) {
   var fast_answer = %_FastCharCodeAt(this, pos);
   if (%_IsSmi(fast_answer)) {
     return fast_answer;
   }
   var subject = TO_STRING_INLINE(this);
@@ skipping 94 matching lines @@
 // SubString is an internal function that returns the sub string of 'string'.
 // If resulting string is of length 1, we use the one character cache
 // otherwise we call the runtime system.
 function SubString(string, start, end) {
   // Use the one character string cache.
   if (start + 1 == end) {
     var char_code = %_FastCharCodeAt(string, start);
     if (!%_IsSmi(char_code)) {
       char_code = %StringCharCodeAt(string, start);
     }
-    return %CharFromCode(char_code);
+    return %_CharFromCode(char_code);
   }
   return %_SubString(string, start, end);
 }
 
 
 // This has the same size as the lastMatchInfo array, and can be used for
 // functions that expect that structure to be returned.  It is used when the
 // needle is a string rather than a regexp.  In this case we can't update
 // lastMatchArray without erroneously affecting the properties on the global
 // RegExp object.
@@ skipping 521 matching lines @@
   return %StringTrim(TO_STRING_INLINE(this), true, false);
 }
 
 function StringTrimRight() {
   return %StringTrim(TO_STRING_INLINE(this), false, true);
 }
 
 // ECMA-262, section 15.5.3.2
 function StringFromCharCode(code) {
   var n = %_ArgumentsLength();
-  if (n == 1) return %CharFromCode(ToNumber(code) & 0xffff)
+  if (n == 1) return %_CharFromCode(ToNumber(code) & 0xffff)
 
   // NOTE: This is not super-efficient, but it is necessary because we
   // want to avoid converting to numbers from within the virtual
   // machine. Maybe we can find another way of doing this?
   var codes = new $Array(n);
   for (var i = 0; i < n; i++) codes[i] = ToNumber(%_Arguments(i));
   return %StringFromCharCodeArray(codes);
 }
 
 
@@ skipping 164 matching lines @@
     "small", StringSmall,
     "strike", StringStrike,
     "sub", StringSub,
     "sup", StringSup,
     "toJSON", StringToJSON
   ));
 }
 
 
 SetupString();