Commit 4a751684 authored by Georg Neis's avatar Georg Neis Committed by Commit Bot

Reland "[typedarray] Properly convert hole to undefined in TypedArray.from"

This is an unmodified reland of ece86adc.

Original change's description:
> [typedarray] Properly convert hole to undefined in TypedArray.from
>
> It used to call the old IterableToList, which had the wrong
> semantics for holes.
>
> Bug: v8:8133
> Change-Id: Idd5acd55a155bc43df7552135a44151bb2db38e9
> Reviewed-on: https://chromium-review.googlesource.com/1213204
> Reviewed-by: Peter Marshall <petermarshall@chromium.org>
> Commit-Queue: Georg Neis <neis@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#55745}

Tbr: petermarshall@chromium.org
Bug: v8:8133
Change-Id: I91c1eaf61cbcc29116e3a6cc3415f29cfba3561e
Reviewed-on: https://chromium-review.googlesource.com/1223007
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: 's avatarGeorg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55846}
parent b14e944d
......@@ -1670,9 +1670,8 @@ TF_BUILTIN(TypedArrayFrom, TypedArrayBuiltinsAssembler) {
// 7. If usingIterator is not undefined, then
// a. Let values be ? IterableToList(source, usingIterator).
// b. Let len be the number of elements in values.
TNode<JSArray> values =
CAST(CallBuiltin(Builtins::kIterableToListMayPreserveHoles, context,
source, iterator_fn));
TNode<JSArray> values = CAST(
CallBuiltin(Builtins::kIterableToList, context, source, iterator_fn));
// This is not a spec'd limit, so it doesn't particularly matter when we
// throw the range error for typed array length > MaxSmi.
......
// Copyright 2018 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.
const arr = [1, , 3];
function mapper(x) {
Array.prototype[1] = 2;
return x + 1;
}
// This iterates over arr using the iterator protocol, which turns the hole into
// undefined. The mapper function then gets called in a separate iteration over
// the acquired elements, where it increments undefined, which produces NaN and
// gets converted to 0.
assertArrayEquals([2, 0, 4], Uint16Array.from(arr, mapper));
// Copyright 2018 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.
const arr = [1, , 3];
function mapper(x) {
Array.prototype[1] = 2;
return x + 1;
}
// We force a direct iteration (using the array length, not the iterator
// protocol). The mapper function gets called during this iteration, not in a
// separate one. Hence when index 1 is read, 2 is retrieved from the prototype
// and incremented to 3.
Array.prototype[Symbol.iterator] = undefined;
assertArrayEquals([2, 3, 4], Uint16Array.from(arr, mapper));
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