Construct instances of base class from TypedArray.prototype.subarray

src/js/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(global, utils) {
 
 "use strict";
 
 %CheckIsBootstrapping();
 
@@ skipping 110 matching lines @@
   if (!%_IsTypedArray(newTypedArray)) throw MakeTypeError(kNotTypedArray);
   // TODO(littledan): Check for being detached, here and elsewhere
   // All callers where the first argument is a Number have no additional
   // arguments.
   if (IS_NUMBER(arg0) && %_TypedArrayGetLength(newTypedArray) < arg0) {
     throw MakeTypeError(kTypedArrayTooShort);
   }
   return newTypedArray;
 }
 
-function TypedArraySpeciesCreate(exemplar, arg0, arg1, arg2) {
+function TypedArraySpeciesCreate(exemplar, arg0, arg1, arg2, conservative) {
   var defaultConstructor = TypedArrayDefaultConstructor(exemplar);
-  var constructor = SpeciesConstructor(exemplar, defaultConstructor);
+  var constructor = SpeciesConstructor(exemplar, defaultConstructor,
+                                       conservative);
   return TypedArrayCreate(constructor, arg0, arg1, arg2);
 }
 
 macro TYPED_ARRAY_CONSTRUCTOR(ARRAY_ID, NAME, ELEMENT_SIZE)
 function NAMEConstructByArrayBuffer(obj, buffer, byteOffset, length) {
   if (!IS_UNDEFINED(byteOffset)) {
     byteOffset = ToPositiveInteger(byteOffset, kInvalidTypedArrayLength);
   }
   if (!IS_UNDEFINED(length)) {
     length = ToPositiveInteger(length, kInvalidTypedArrayLength);
@@ skipping 141 matching lines @@
   }
 
   if (endInt < beginInt) {
     endInt = beginInt;
   }
 
   var newLength = endInt - beginInt;
   var beginByteOffset =
       %_ArrayBufferViewGetByteOffset(this) + beginInt * ELEMENT_SIZE;
   return TypedArraySpeciesCreate(this, %TypedArrayGetBuffer(this),
-                                 beginByteOffset, newLength);
+                                 beginByteOffset, newLength, true);
 }
 endmacro
 
 TYPED_ARRAYS(TYPED_ARRAY_CONSTRUCTOR)
 
 function TypedArraySubArray(begin, end) {
   switch (%_ClassOf(this)) {
 macro TYPED_ARRAY_SUBARRAY_CASE(ARRAY_ID, NAME, ELEMENT_SIZE)
     case "NAME":
       return %_Call(NAMESubArray, this, begin, end);
@@ skipping 653 matching lines @@
   "setUint32", DataViewSetUint32JS,
 
   "getFloat32", DataViewGetFloat32JS,
   "setFloat32", DataViewSetFloat32JS,
 
   "getFloat64", DataViewGetFloat64JS,
   "setFloat64", DataViewSetFloat64JS
 ]);
 
 })