[builtins] Remove almost all remaining uses of %_Arguments and %_ArgumentsLength.

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 63 matching lines @@
   var result = %_StringCharCodeAt(this, pos);
   if (!%_IsSmi(result)) {
     result = %_StringCharCodeAt(TO_STRING(this), TO_INTEGER(pos));
   }
   return result;
 }
 
 
 // ECMA-262, section 15.5.4.6
 function StringConcat(other /* and more */) {  // length == 1
+  "use strict";
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.concat");
-  var len = %_ArgumentsLength();
-  var this_as_string = TO_STRING(this);
-  if (len === 1) {
-    return this_as_string + TO_STRING(other);
+  var s = TO_STRING(this);
+  var len = arguments.length;
+  for (var i = 0; i < len; ++i) {
+    s = s + TO_STRING(arguments[i]);
   }
-  var parts = new InternalArray(len + 1);
-  parts[0] = this_as_string;
-  for (var i = 0; i < len; i++) {
-    var part = %_Arguments(i);
-    parts[i + 1] = TO_STRING(part);
-  }
-  return %StringBuilderConcat(parts, len + 1, "");
+  return s;
 }
 
 
 // ECMA-262 section 15.5.4.7
-function StringIndexOfJS(pattern /* position */) {  // length == 1
+function StringIndexOf(pattern, position) {  // length == 1
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.indexOf");
 
   var subject = TO_STRING(this);
   pattern = TO_STRING(pattern);
-  var index = 0;
-  if (%_ArgumentsLength() > 1) {
-    index = %_Arguments(1);  // position
-    index = TO_INTEGER(index);
-    if (index < 0) index = 0;
-    if (index > subject.length) index = subject.length;
-  }
+  var index = TO_INTEGER(position);
+  if (index < 0) index = 0;
+  if (index > subject.length) index = subject.length;
   return %StringIndexOf(subject, pattern, index);
 }
 
+%FunctionSetLength(StringIndexOf, 1);
+
 
 // ECMA-262 section 15.5.4.8
 function StringLastIndexOfJS(pat /* position */) {  // length == 1
+  "use strict";
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.lastIndexOf");
 
   var sub = TO_STRING(this);
   var subLength = sub.length;
   var pat = TO_STRING(pat);
   var patLength = pat.length;
   var index = subLength - patLength;
-  if (%_ArgumentsLength() > 1) {
-    var position = TO_NUMBER(%_Arguments(1));
+  if (arguments.length > 1) {

[Yang, 2016/02/12 09:25:39]

why not do the same thing as for StringIndexOf?

[Benedikt Meurer, 2016/02/12 09:30:14]

Done.

+    var position = TO_NUMBER(arguments[1]);
     if (!NUMBER_IS_NAN(position)) {
       position = TO_INTEGER(position);
       if (position < 0) {
         position = 0;
       }
       if (position + patLength < subLength) {
         index = position;
       }
     }
   }
@@ skipping 33 matching lines @@
   return RegExpExecNoTests(regexp, subject, 0);
 }
 
 
 // ECMA-262 v6, section 21.1.3.12
 //
 // For now we do nothing, as proper normalization requires big tables.
 // If Intl is enabled, then i18n.js will override it and provide the the
 // proper functionality.
 function StringNormalizeJS() {
+  "use strict";
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.normalize");
   var s = TO_STRING(this);
 
-  var formArg = %_Arguments(0);
+  var formArg = arguments[0];

[Yang, 2016/02/12 09:25:39]

I also prefer SetFunctionLength for this as well.

[Benedikt Meurer, 2016/02/12 09:30:14]

Done.

   var form = IS_UNDEFINED(formArg) ? 'NFC' : TO_STRING(formArg);
 
   var NORMALIZATION_FORMS = ['NFC', 'NFD', 'NFKC', 'NFKD'];
   var normalizationForm = %_Call(ArrayIndexOf, NORMALIZATION_FORMS, form);
   if (normalizationForm === -1) {
     throw MakeRangeError(kNormalizationForm,
                          %_Call(ArrayJoin, NORMALIZATION_FORMS, ', '));
   }
 
   return s;
@@ skipping 365 matching lines @@
 function StringTrimRight() {
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.trimRight");
 
   return %StringTrim(TO_STRING(this), false, true);
 }
 
 
 // ECMA-262, section 15.5.3.2
 function StringFromCharCode(code) {
   var n = %_ArgumentsLength();
-  if (n == 1) return %_StringCharFromCode(code & 0xffff);
+  if (n === 1) return %_StringCharFromCode(code & 0xffff);
 
   var one_byte = %NewString(n, NEW_ONE_BYTE_STRING);
   var i;
   for (i = 0; i < n; i++) {
     code = %_Arguments(i) & 0xffff;
     if (code > 0xff) break;
     %_OneByteSeqStringSetChar(i, code, one_byte);
   }
   if (i == n) return one_byte;
   one_byte = %TruncateString(one_byte, i);
@@ skipping 128 matching lines @@
   while (true) {
     if (n & 1) r += s;
     n >>= 1;
     if (n === 0) return r;
     s += s;
   }
 }
 
 
 // ES6 draft 04-05-14, section 21.1.3.18
-function StringStartsWith(searchString /* position */) {  // length == 1
+function StringStartsWith(searchString, position) {  // length == 1
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.startsWith");
 
   var s = TO_STRING(this);
 
   if (IS_REGEXP(searchString)) {
     throw MakeTypeError(kFirstArgumentNotRegExp, "String.prototype.startsWith");
   }
 
   var ss = TO_STRING(searchString);
-  var pos = 0;
-  if (%_ArgumentsLength() > 1) {
-    var arg = %_Arguments(1);  // position
-    if (!IS_UNDEFINED(arg)) {
-      pos = TO_INTEGER(arg);
-    }
-  }
+  var pos = TO_INTEGER(position);
 
   var s_len = s.length;
   var start = MinSimple(MaxSimple(pos, 0), s_len);
   var ss_len = ss.length;
   if (ss_len + start > s_len) {
     return false;
   }
 
   return %_SubString(s, start, start + ss_len) === ss;
 }
 
+%FunctionSetLength(StringStartsWith, 1);
+
 
 // ES6 draft 04-05-14, section 21.1.3.7
-function StringEndsWith(searchString /* position */) {  // length == 1
+function StringEndsWith(searchString, position) {  // length == 1
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.endsWith");
 
   var s = TO_STRING(this);
 
   if (IS_REGEXP(searchString)) {
     throw MakeTypeError(kFirstArgumentNotRegExp, "String.prototype.endsWith");
   }
 
   var ss = TO_STRING(searchString);
   var s_len = s.length;
-  var pos = s_len;
-  if (%_ArgumentsLength() > 1) {
-    var arg = %_Arguments(1);  // position
-    if (!IS_UNDEFINED(arg)) {
-      pos = TO_INTEGER(arg);
-    }
-  }
+  var pos = !IS_UNDEFINED(position) ? TO_INTEGER(position) : s_len
 
   var end = MinSimple(MaxSimple(pos, 0), s_len);
   var ss_len = ss.length;
   var start = end - ss_len;
   if (start < 0) {
     return false;
   }
 
   return %_SubString(s, start, start + ss_len) === ss;
 }
 
+%FunctionSetLength(StringEndsWith, 1);
+
 
 // ES6 draft 04-05-14, section 21.1.3.6
-function StringIncludes(searchString /* position */) {  // length == 1
+function StringIncludes(searchString, position) {  // length == 1
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.includes");
 
   var string = TO_STRING(this);
 
   if (IS_REGEXP(searchString)) {
     throw MakeTypeError(kFirstArgumentNotRegExp, "String.prototype.includes");
   }
 
   searchString = TO_STRING(searchString);
-  var pos = 0;
-  if (%_ArgumentsLength() > 1) {
-    pos = %_Arguments(1);  // position
-    pos = TO_INTEGER(pos);
-  }
+  var pos = TO_INTEGER(position);
 
   var stringLength = string.length;
   if (pos < 0) pos = 0;
   if (pos > stringLength) pos = stringLength;
   var searchStringLength = searchString.length;
 
   if (searchStringLength + pos > stringLength) {
     return false;
   }
 
   return %StringIndexOf(string, searchString, pos) !== -1;
 }
 
+%FunctionSetLength(StringIncludes, 1);
+
 
 // ES6 Draft 05-22-2014, section 21.1.3.3
 function StringCodePointAt(pos) {
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.codePointAt");
 
   var string = TO_STRING(this);
   var size = string.length;
   pos = TO_INTEGER(pos);
   if (pos < 0 || pos >= size) {
     return UNDEFINED;
   }
   var first = %_StringCharCodeAt(string, pos);
   if (first < 0xD800 || first > 0xDBFF || pos + 1 == size) {
     return first;
   }
   var second = %_StringCharCodeAt(string, pos + 1);
   if (second < 0xDC00 || second > 0xDFFF) {
     return first;
   }
   return (first - 0xD800) * 0x400 + second + 0x2400;
 }
 
 
 // ES6 Draft 05-22-2014, section 21.1.2.2
 function StringFromCodePoint(_) {  // length = 1
+  "use strict";
   var code;
-  var length = %_ArgumentsLength();
+  var length = arguments.length;
   var index;
   var result = "";
   for (index = 0; index < length; index++) {
-    code = %_Arguments(index);
+    code = arguments[index];
     if (!%_IsSmi(code)) {
       code = TO_NUMBER(code);
     }
     if (code < 0 || code > 0x10FFFF || code !== TO_INTEGER(code)) {
       throw MakeRangeError(kInvalidCodePoint, code);
     }
     if (code <= 0xFFFF) {
       result += %_StringCharFromCode(code);
     } else {
       code -= 0x10000;
       result += %_StringCharFromCode((code >>> 10) & 0x3FF | 0xD800);
       result += %_StringCharFromCode(code & 0x3FF | 0xDC00);
     }
   }
   return result;
 }
 
 
 // -------------------------------------------------------------------
 // String methods related to templates
 
 // ES6 Draft 03-17-2015, section 21.1.2.4
 function StringRaw(callSite) {
-  // TODO(caitp): Use rest parameters when implemented
-  var numberOfSubstitutions = %_ArgumentsLength();
+  "use strict";
+  var numberOfSubstitutions = arguments.length;
   var cooked = TO_OBJECT(callSite);
   var raw = TO_OBJECT(cooked.raw);
   var literalSegments = TO_LENGTH(raw.length);
   if (literalSegments <= 0) return "";
 
   var result = TO_STRING(raw[0]);
 
   for (var i = 1; i < literalSegments; ++i) {
     if (i < numberOfSubstitutions) {
-      result += TO_STRING(%_Arguments(i));
+      result += TO_STRING(arguments[i]);
     }
     result += TO_STRING(raw[i]);
   }
 
   return result;
 }
 
 // -------------------------------------------------------------------
 
 // Set the String function and constructor.
@@ skipping 13 matching lines @@
 // Set up the non-enumerable functions on the String prototype object.
 utils.InstallFunctions(GlobalString.prototype, DONT_ENUM, [
   "valueOf", StringValueOf,
   "toString", StringToString,
   "charAt", StringCharAtJS,
   "charCodeAt", StringCharCodeAtJS,
   "codePointAt", StringCodePointAt,
   "concat", StringConcat,
   "endsWith", StringEndsWith,
   "includes", StringIncludes,
-  "indexOf", StringIndexOfJS,
+  "indexOf", StringIndexOf,
   "lastIndexOf", StringLastIndexOfJS,
   "localeCompare", StringLocaleCompareJS,
   "match", StringMatchJS,
   "normalize", StringNormalizeJS,
   "repeat", StringRepeat,
   "replace", StringReplace,
   "search", StringSearch,
   "slice", StringSlice,
   "split", StringSplitJS,
   "substring", StringSubstring,
@@ skipping 21 matching lines @@
   "sub", StringSub,
   "sup", StringSup
 ]);
 
 // -------------------------------------------------------------------
 // Exports
 
 utils.Export(function(to) {
   to.ExpandReplacement = ExpandReplacement;
   to.StringCharAt = StringCharAtJS;
-  to.StringIndexOf = StringIndexOfJS;
+  to.StringIndexOf = StringIndexOf;
   to.StringLastIndexOf = StringLastIndexOfJS;
   to.StringMatch = StringMatchJS;
   to.StringReplace = StringReplace;
   to.StringSlice = StringSlice;
   to.StringSplit = StringSplitJS;
   to.StringSubstr = StringSubstr;
   to.StringSubstring = StringSubstring;
 });
 
 })