v8/test/mjsunit/regress/regress-1143772.js
Leszek Swirski 8e3ae62d29 [map] Try to in-place transition during map update
When searching for a target map during map update, attempt to
update field representations in-place to the more general
representation, where possible.

Bug: chromium:1143772
Change-Id: I6a43c94910a1d2d8f8b0ad89048f94b51461f76c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2507715
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70887}
2020-10-29 21:26:16 +00:00

72 lines
1.7 KiB
JavaScript

// Copyright 2020 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.
//
// Flags: --allow-natives-syntax
(function() {
// Only run this test if doubles are transitioned in-place to tagged.
let x = {};
x.a = 0.1;
let y = {};
y.a = {};
if (!%HaveSameMap(x, y)) return;
// m1: {}
let m1 = {};
// m2: {a:d}
let m2 = {};
assertTrue(%HaveSameMap(m2, m1));
m2.a = 13.37;
// m3: {a:d, b:s}
let m3 = {};
m3.a = 13.37;
assertTrue(%HaveSameMap(m3, m2));
m3.b = 1;
// m4: {a:d, b:s, c:h}
let m4 = {};
m4.a = 13.37;
m4.b = 1;
assertTrue(%HaveSameMap(m4, m3));
m4.c = {};
// m4_2 == m4
let m4_2 = {};
m4_2.a = 13.37;
m4_2.b = 1;
m4_2.c = {};
assertTrue(%HaveSameMap(m4_2, m4));
// m5: {a:d, b:d}
let m5 = {};
m5.a = 13.37;
assertTrue(%HaveSameMap(m5, m2));
m5.b = 13.37;
assertFalse(%HaveSameMap(m5, m3));
// At this point, Map3 and Map4 are both deprecated. Map2 transitions to
// Map5. Map5 is the migration target for Map3.
assertFalse(%HaveSameMap(m5, m3));
// m6: {a:d, b:d, c:d}
let m6 = {};
m6.a = 13.37;
assertTrue(%HaveSameMap(m6, m2));
m6.b = 13.37;
assertTrue(%HaveSameMap(m6, m5));
m6.c = 13.37
// Make m7: {a:d, b:d, c:t}
let m7 = m4_2;
assertTrue(%HaveSameMap(m7, m4));
// Map4 is deprecated, so this property access triggers a Map migration.
// With in-place map updates and no double unboxing, this should end up
// migrating to Map6, and updating it in-place.
m7.c;
assertFalse(%HaveSameMap(m7, m4));
assertTrue(%HaveSameMap(m6, m7));
})();