Make one copy for all TypedArray methods

src/typedarray.js

 // Copyright 2013 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() {
 
 "use strict";
 
 %CheckIsBootstrapping();
 
@@ skipping 135 matching lines @@
   }
   return %_ArrayBufferViewGetByteOffset(this);
 }
 
 function NAME_GetLength() {
   if (!(%_ClassOf(this) === 'NAME')) {
     throw MakeTypeError(kIncompatibleMethodReceiver, "NAME.length", this);
   }
   return %_TypedArrayGetLength(this);
 }
+endmacro
 
-function NAMESubArray(begin, end) {
-  if (!(%_ClassOf(this) === 'NAME')) {
-    throw MakeTypeError(kIncompatibleMethodReceiver, "NAME.subarray", this);
+function TypedArraySubArray(begin, end) {

[adamk, 2015/05/08 01:13:34]

We probably want to change this in the future, but I'd like to limit the changes
you're making in this one to what's behind the --harmony-arrays flag (and thus
won't affect what we're currently shipping).

+  if (!%IsTypedArray(this)) {
+    throw MakeTypeError('not_typed_array', []);
   }
   var beginInt = TO_INTEGER(begin);
   if (!IS_UNDEFINED(end)) {
     end = TO_INTEGER(end);
   }
 
   var srcLength = %_TypedArrayGetLength(this);
   if (beginInt < 0) {
     beginInt = $max(0, srcLength + beginInt);
   } else {
     beginInt = $min(srcLength, beginInt);
   }
 
   var endInt = IS_UNDEFINED(end) ? srcLength : end;
   if (endInt < 0) {
     endInt = $max(0, srcLength + endInt);
   } else {
     endInt = $min(endInt, srcLength);
   }
   if (endInt < beginInt) {
     endInt = beginInt;
   }
   var newLength = endInt - beginInt;
   var beginByteOffset =
-      %_ArrayBufferViewGetByteOffset(this) + beginInt * ELEMENT_SIZE;
-  return new GlobalNAME(%TypedArrayGetBuffer(this),
-                        beginByteOffset, newLength);
+      %_ArrayBufferViewGetByteOffset(this) + beginInt * this.BYTES_PER_ELEMENT;
+  return new this.constructor(%TypedArrayGetBuffer(this),
+                              beginByteOffset, newLength);
 }
-endmacro
 
 TYPED_ARRAYS(TYPED_ARRAY_CONSTRUCTOR)
 
 
 function TypedArraySetFromArrayLike(target, source, sourceLength, offset) {
   if (offset > 0) {
     for (var i = 0; i < sourceLength; i++) {
       target[offset + i] = source[i];
     }
   }
@@ skipping 116 matching lines @@
   $installGetter(GlobalNAME.prototype, "buffer", NAME_GetBuffer);
   $installGetter(GlobalNAME.prototype, "byteOffset", NAME_GetByteOffset,
                  DONT_ENUM | DONT_DELETE);
   $installGetter(GlobalNAME.prototype, "byteLength", NAME_GetByteLength,
                  DONT_ENUM | DONT_DELETE);
   $installGetter(GlobalNAME.prototype, "length", NAME_GetLength,
                  DONT_ENUM | DONT_DELETE);
   $installGetter(GlobalNAME.prototype, symbolToStringTag,
                  TypedArrayGetToStringTag);
   $installFunctions(GlobalNAME.prototype, DONT_ENUM, [
-    "subarray", NAMESubArray,
+    "subarray", TypedArraySubArray,
     "set", TypedArraySet
   ]);
 endmacro
 
 TYPED_ARRAYS(SETUP_TYPED_ARRAY)
 
 // --------------------------- DataView -----------------------------
 
 function DataViewConstructor(buffer, byteOffset, byteLength) { // length = 3
   if (%_IsConstructCall()) {
@@ skipping 115 matching lines @@
   "setUint32", DataViewSetUint32JS,
 
   "getFloat32", DataViewGetFloat32JS,
   "setFloat32", DataViewSetFloat32JS,
 
   "getFloat64", DataViewGetFloat64JS,
   "setFloat64", DataViewSetFloat64JS
 ]);
 
 })();