v8/test/mjsunit/es9/regress/regress-867958.js
Caitlin Potter 5caee70b66 Reland "Reland [CloneObjectIC] overwrite monomorphic/polymorphic feedback if deprecated"
An object with a deprecated Map which has already been cached in
CloneObjectIC feedback is still a valid Map for fast cloning --- but
to be consistent with other ICs, deprecated maps are ignored, and are
expected to be transitioned away from.

If the source object has a deprecated map, the instance is migrated.

BUG=v8:7611, chromium:867958, chromium:868586, chromium:869342, chromium:869347, chromium:869293
R=jkummerow@chromium.org, mvstanton@chromium.org

Reviewed-on: https://chromium-review.googlesource.com/1154143
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#54799}
Change-Id: I6e2f7b28c41bb9bd6255441da0f209a97bce5e8f
Reviewed-on: https://chromium-review.googlesource.com/1157142
Cr-Commit-Position: refs/heads/master@{#54830}
2018-08-01 00:30:11 +00:00

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JavaScript

// 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.
// Check that encountering deprecated Maps does not cause CloneObjectIC to
// crash.
var obj1 = { x: 1 };
var obj2 = { x: 2 }; // same map
obj2.x = null; // deprecate map
function f() { return { ...obj1 } };
assertEquals({ x: 1 }, f()); // missed, object migrated to cached new map
assertEquals({ x: 1 }, f()); // monomorphic cache-hit