[stubs] Port String.prototype.substr to TurboFan

src/js/string.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 (function(global, utils) {
 
 %CheckIsBootstrapping();
 
 // -------------------------------------------------------------------
 // Imports
@@ skipping 219 matching lines @@
   if (IS_UNDEFINED(separator)) return [subject];
 
   var separator_length = separator_string.length;
 
   // If the separator string is empty then return the elements in the subject.
   if (separator_length === 0) return %StringToArray(subject, limit);
 
   return %StringSplit(subject, separator_string, limit);
 }
 
-// ecma262/#sec-string.prototype.substr
-function StringSubstr(start, length) {
-  CHECK_OBJECT_COERCIBLE(this, "String.prototype.substr");
-  var s = TO_STRING(this);
-  var size = s.length;
-  start = TO_INTEGER(start);
-  length = IS_UNDEFINED(length) ? size : TO_INTEGER(length);
-
-  if (start < 0) start = MaxSimple(size + start, 0);
-  length = MinSimple(MaxSimple(length, 0), size - start);
-
-  if (length <= 0) return '';
-  return %_SubString(s, start, start + length);
-}
-
 
 // ECMA-262, 15.5.4.16
 function StringToLowerCaseJS() {
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.toLowerCase");
 
   return %StringToLowerCase(TO_STRING(this));
 }
 
 
 // ECMA-262, 15.5.4.17
@@ skipping 285 matching lines @@
   "concat", StringConcat,
   "endsWith", StringEndsWith,
   "includes", StringIncludes,
   "indexOf", StringIndexOf,
   "match", StringMatchJS,
   "repeat", StringRepeat,
   "replace", StringReplace,
   "search", StringSearch,
   "slice", StringSlice,
   "split", StringSplitJS,
-  "substr", StringSubstr,
   "startsWith", StringStartsWith,
   "toLowerCase", StringToLowerCaseJS,
   "toLocaleLowerCase", StringToLocaleLowerCase,
   "toUpperCase", StringToUpperCaseJS,
   "toLocaleUpperCase", StringToLocaleUpperCase,
 
   "link", StringLink,
   "anchor", StringAnchor,
   "fontcolor", StringFontcolor,
   "fontsize", StringFontsize,
@@ skipping 10 matching lines @@
 
 // -------------------------------------------------------------------
 // Exports
 
 utils.Export(function(to) {
   to.StringIndexOf = StringIndexOf;
   to.StringMatch = StringMatchJS;
   to.StringReplace = StringReplace;
   to.StringSlice = StringSlice;
   to.StringSplit = StringSplitJS;
-  to.StringSubstr = StringSubstr;
 });
 
 })