1614650 - Assert that finalizers don't rely on the mark state of other cells

Status: RESOLVED FIXED

(Core :: JavaScript: GC, task, P1)

Description

[Jon Coppeard (:jonco)]

Allowing finalizers to make use of the mark state of other cells (e.g. by using IsMarked or IsAboutToBeFinalized) creates a dependency that prevents us reusing free arenas until anything that might need to access their mark state has been finalized. Such dependencies are hard to see but getting this wrong leads to crashes.

We don't do this any more, and we should add assertions to ensure that we don't start doing it again.

Comment 1

[Jon Coppeard (:jonco)]

Attachment: Bug 1614650 - Assert that finalizers don't rely on the mark state of other cells r?sfink,mccr8

This gives JSContext a more fine-grained view of which part of the GC is running on its thread, to separate out finalization from sweeping generally.

I had to remove an assertion in xpconnect which was the only place where this currently happened.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/4d9e588f6357
Assert that finalizers don't rely on the mark state of other cells r=sfink,mccr8

Comment 3

[Razvan Maries]

https://hg.mozilla.org/mozilla-central/rev/4d9e588f6357