Custom call IC-s for String.prototype.{charAt,charCodeAt}.

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 44 matching lines @@
 // ECMA-262 section 15.5.4.3
 function StringValueOf() {
   if (!IS_STRING(this) && !IS_STRING_WRAPPER(this))
     throw new $TypeError('String.prototype.valueOf is not generic');
   return %_ValueOf(this);
 }
 
 
 // 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);
+  var result = %_StringCharAt(this, pos);
+  if (%_IsSmi(result)) {
+    result = %_StringCharAt(TO_STRING_INLINE(this), TO_INTEGER(pos));
   }
-  return %_CharFromCode(char_code);
+  return result;
 }
 
 
 // ECMA-262 section 15.5.4.5
 function StringCharCodeAt(pos) {
-  var fast_answer = %_FastCharCodeAt(this, pos);
-  if (%_IsSmi(fast_answer)) {
-    return fast_answer;
+  var result = %_StringCharCodeAt(this, pos);
+  if (!%_IsSmi(result)) {
+    result = %_StringCharCodeAt(TO_STRING_INLINE(this), TO_INTEGER(pos));
   }
-  var subject = TO_STRING_INLINE(this);
-  var index = TO_INTEGER(pos);
-  return %StringCharCodeAt(subject, index);
+  return result;
 }
 
 
 // ECMA-262, section 15.5.4.6
 function StringConcat() {
   var len = %_ArgumentsLength();
   var this_as_string = TO_STRING_INLINE(this);
   if (len === 1) {
     return this_as_string + %_Arguments(0);
   }
@@ skipping 112 matching lines @@
   return RegExpExecNoTests(regexp, subject, 0);
 }
 
 
 // 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 %_StringCharAt(string, start);
   }
   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 83 matching lines @@
   // Compute the number of captures; see ECMA-262, 15.5.4.11, p. 102.
   var m = NUMBER_OF_CAPTURES(matchInfo) >> 1;  // Includes the match.
 
   if (next > 0) builder.add(SubString(string, 0, next));
   var length = string.length;
 
   while (true) {
     var expansion = '$';
     var position = next + 1;
     if (position < length) {
-      var peek = %_FastCharCodeAt(string, position);
-      if (!%_IsSmi(peek)) {
-        peek = %StringCharCodeAt(string, position);
-      }
+      var peek = %_StringCharCodeAt(string, position);
       if (peek == 36) {         // $$
         ++position;
         builder.add('$');
       } else if (peek == 38) {  // $& - match
         ++position;
         builder.addSpecialSlice(matchInfo[CAPTURE0],
                                 matchInfo[CAPTURE1]);
       } else if (peek == 96) {  // $` - prefix
         ++position;
         builder.addSpecialSlice(0, matchInfo[CAPTURE0]);
       } else if (peek == 39) {  // $' - suffix
         ++position;
         builder.addSpecialSlice(matchInfo[CAPTURE1], subject.length);
       } else if (peek >= 48 && peek <= 57) {  // $n, 0 <= n <= 9
         ++position;
         var n = peek - 48;
         if (position < length) {
-          peek = %_FastCharCodeAt(string, position);
-          if (!%_IsSmi(peek)) {
-            peek = %StringCharCodeAt(string, position);
-          }
+          peek = %_StringCharCodeAt(string, position);
           // $nn, 01 <= nn <= 99
           if (n != 0 && peek == 48 || peek >= 49 && peek <= 57) {
             var nn = n * 10 + (peek - 48);
             if (nn < m) {
               // If the two digit capture reference is within range of
               // the captures, we use it instead of the single digit
               // one. Otherwise, we fall back to using the single
               // digit reference. This matches the behavior of
               // SpiderMonkey.
               ++position;
@@ skipping 457 matching lines @@
   return %StringTrim(TO_STRING_INLINE(this), false, true);
 }
 
 var static_charcode_array = new $Array(4);
 
 // ECMA-262, section 15.5.3.2
 function StringFromCharCode(code) {
   var n = %_ArgumentsLength();
   if (n == 1) {
     if (!%_IsSmi(code)) code = ToNumber(code);
-    return %_CharFromCode(code & 0xffff);
+    return %_StringCharFromCode(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 = static_charcode_array;
   for (var i = 0; i < n; i++) {
     var code = %_Arguments(i);
     if (!%_IsSmi(code)) code = ToNumber(code);
     codes[i] = code;
@@ skipping 174 matching lines @@
     "small", StringSmall,
     "strike", StringStrike,
     "sub", StringSub,
     "sup", StringSup,
     "toJSON", StringToJSON
   ));
 }
 
 
 SetupString();