06ba822ead
This adds support for integrity level transitions (preventExtensions,
seal and freeze) to MapUpdater and Map::TryUpdate.
In both cases, we first try to detect whether there were integrity
level transitions in the transition tree to the old map and make note
of the most restrictive integrity transition and the map just before
the transition (integrity-source-map). Then we find an appropriate root
(based on integrity-source-map's elements kind) and replay the
transitions based on the integrity-source-map's descriptor
array. Finally, if we saw an integrity level transition in
the beginning, we will find-or-create that transition (on the
updated version of integrity-source-map).
For the following micro-benchmark, we get about 10x speedup.
```
function C() {
this.x = 1;
Object.seal(this);
this.x = 0.1;
}
const start = Date.now();
for (let i = 0; i < 1e7; i++) {
new C();
}
console.log("Reconfigure sealed: " + (Date.now() - start));
```
Before:
> Reconfigure sealed: 5202
After:
> Reconfigure sealed: 479
Bug: v8:8538
Change-Id: If695be7469d8b6ccd44ac4528be8aa34b65b3e4d
Reviewed-on: https://chromium-review.googlesource.com/c/1442640
Commit-Queue: Jaroslav Sevcik <jarin@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59295}
167 lines
3.2 KiB
JavaScript
167 lines
3.2 KiB
JavaScript
// Copyright 2019 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// Flags: --allow-natives-syntax
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(function SealAndReconfigure() {
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function C() { this.x = 1; this.y = 1; Object.seal(this); }
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let c1 = new C();
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c1.x = 0.1;
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let c2 = new C();
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let c3 = new C();
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let c4 = new C();
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// The objects c2, c3 and c4 should follow the same transition
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// path that we reconfigured c1 to.
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assertTrue(%HaveSameMap(c1, c2));
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assertTrue(%HaveSameMap(c1, c3));
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assertTrue(%HaveSameMap(c1, c4));
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c2.x = 0.1;
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c3.x = 0.1;
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c4.x = 0.1;
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assertTrue(%HaveSameMap(c1, c2));
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assertTrue(%HaveSameMap(c1, c3));
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assertTrue(%HaveSameMap(c1, c4));
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})();
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(function SealAndReconfigureWithIC() {
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function C() { this.x = 1; this.y = 1; Object.seal(this); }
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let c1 = new C();
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function g(o) {
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o.x = 0.1;
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}
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g(c1);
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let c2 = new C();
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let c3 = new C();
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let c4 = new C();
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// The objects c2, c3 and c4 should follow the same transition
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// path that we reconfigured c1 to.
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assertTrue(%HaveSameMap(c1, c2));
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assertTrue(%HaveSameMap(c1, c3));
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assertTrue(%HaveSameMap(c1, c4));
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g(c2);
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g(c3);
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g(c4);
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assertTrue(%HaveSameMap(c1, c2));
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assertTrue(%HaveSameMap(c1, c3));
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assertTrue(%HaveSameMap(c1, c4));
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})();
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(function SealReconfigureAndMigrateWithIC() {
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function C() { this.x = 1; this.y = 1; Object.seal(this); }
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let c1 = new C();
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let c2 = new C();
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let c3 = new C();
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let c4 = new C();
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function g(o) {
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o.x = 0.1;
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}
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g(c1);
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// Now c2, c3 and c4 have deprecated maps.
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assertFalse(%HaveSameMap(c1, c2));
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assertFalse(%HaveSameMap(c1, c3));
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assertFalse(%HaveSameMap(c1, c4));
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g(c2);
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g(c3);
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g(c4);
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assertTrue(%HaveSameMap(c1, c2));
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assertTrue(%HaveSameMap(c1, c3));
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assertTrue(%HaveSameMap(c1, c4));
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})();
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(function SealReconfigureAndMigrateWithOptCode() {
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function C() { this.x = 1; this.y = 1; Object.seal(this); }
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let c1 = new C();
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let c2 = new C();
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let c3 = new C();
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let c4 = new C();
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function g(o) {
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o.x = 0.1;
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}
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g(c1);
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g(c2);
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g(c3);
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%OptimizeFunctionOnNextCall(g);
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g(c4);
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assertTrue(%HaveSameMap(c1, c2));
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assertTrue(%HaveSameMap(c1, c3));
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assertTrue(%HaveSameMap(c1, c4));
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})();
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(function PreventExtensionsAndReconfigure() {
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function C() { this.x = 1; this.y = 1; Object.preventExtensions(this); }
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let c1 = new C();
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function g(o) {
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o.x = 0.1;
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}
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g(c1);
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let c2 = new C();
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let c3 = new C();
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let c4 = new C();
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c2.x = 0.1;
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c3.x = 0.1;
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c4.x = 0.1;
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assertTrue(%HaveSameMap(c1, c2));
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assertTrue(%HaveSameMap(c1, c3));
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assertTrue(%HaveSameMap(c1, c4));
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})();
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(function PreventExtensionsSealAndReconfigure() {
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function C() {
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this.x = 1;
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this.y = 1;
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Object.preventExtensions(this);
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Object.seal(this);
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}
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let c1 = new C();
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function g(o) {
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o.x = 0.1;
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}
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g(c1);
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let c2 = new C();
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let c3 = new C();
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let c4 = new C();
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c2.x = 0.1;
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c3.x = 0.1;
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c4.x = 0.1;
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// Ideally, all the objects would have the same map, but at the moment
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// we shortcut the unnecessary integrity level transitions.
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assertTrue(%HaveSameMap(c2, c3));
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assertTrue(%HaveSameMap(c2, c4));
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})();
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