743ce7726d
Previously, this was run as a microtask and this CL changes it to run
as a separate task as mandated by the current WeakRef spec.
This CL also introduces a FinalizationGroup type to the V8 API
representing the JSFinalizationGroup. This has a `Cleanup`
function that runs the cleanup callback associated with it.
SetHostCleanupFinalizationGroupCallback is added to set
the embedder defined HostCleanupFinalizationGroupCallback.
ClearKeptObject is exposed on the v8::Isolate to reset the strongly
held set of objects.
The general workflow is the following:
(a) When the GC notices that a given finalization group has dirty
cells, it calls HostCleanupFinalizationGroupCallback with the given
finalization group.
(b) As part of HostCleanupFinalizationGroupCallback, the embedder
enqueues a task that at some point later calls
FinalizationGroup::Cleanup.
(c) At some point in the future, FinalizationGroup::Cleanup is called,
which runs the cleanup callback of the finalization group.
This patch also includes d8 changes to use these new APIs. Currently,
d8 cycles through the enqueued finalization groups after a synchronous
turn (and it's microtask checkpoint) and runs the cleanup callbacks.
Change-Id: I06eb4da2c103b2792a9c62bc4b98fd4e5c4892fc
Bug: v8:8179
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1655655
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62984}
63 lines
1.5 KiB
JavaScript
63 lines
1.5 KiB
JavaScript
// Copyright 2018 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: --harmony-weak-refs --expose-gc --noincremental-marking --allow-natives-syntax
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// This test asserts that the cleanup function call, scheduled by GC, is a
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// microtask and not a normal task.
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// Inside a microtask, cause GC (which should schedule the cleanup as
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// microtask). lso schedule another microtask. Assert that the cleanup
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// function ran before the other microtask.
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let cleanedUp = false;
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function scheduleMicrotask(func) {
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Promise.resolve().then(func);
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}
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let log = [];
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let cleanup = (iter) => {
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cleanedUp = true;
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for (holdings of iter) { }
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}
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let fg = new FinalizationGroup(cleanup);
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let o = null;
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(function() {
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// Use a closure here to avoid other references to o which might keep it alive
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// (e.g., stack frames pointing to it).
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o = {};
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fg.register(o, {});
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})();
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let microtask = function() {
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log.push("first_microtask");
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// cause GC during a microtask
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o = null;
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gc();
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}
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assertFalse(cleanedUp);
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// enqueue microtask that triggers GC
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Promise.resolve().then(microtask);
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// but cleanup callback hasn't been called yet, as we're still in
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// synchronous execution
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assertFalse(cleanedUp);
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// flush the microtask queue to run the microtask that triggers GC
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%PerformMicrotaskCheckpoint();
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// still no cleanup callback, because it runs after as a separate task
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assertFalse(cleanedUp);
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setTimeout(() => {
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assertTrue(cleanedUp);
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}, 0);
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