1802087 - Remove heap writes during marking

Status: RESOLVED FIXED

(Core :: JavaScript: GC, task, P3)

Description

[Jon Coppeard (:jonco)]

To enable parallel marking we need to remove any writes to the heap made as part of marking, as these would be data races. Fortunately there are only a couple of places where this happens.

Comment 1

[Jon Coppeard (:jonco)]

Attachment: Bug 1802087 - Part 1: Discard JIT code for RegExpShared objects at the start of GC r?jandem

Currently we discard JIT code for RegExpShared by clearing fields during
marking. The patch changes this to do this at the start of GC.

This is a slight pessimisation as it happens for all RegExpShared objects
including unreachable ones. I don't expect this to be noticable in practice.

Comment 2

[Jon Coppeard (:jonco)]

Attachment: Bug 1802087 - Part 2: Don't update null entries in the script GC things vector r?jandem

This refactors the code to move the update into the GC.

Depends on D162820

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e773f946fcf4
Part 1: Discard JIT code for RegExpShared objects at the start of GC r=jandem
https://hg.mozilla.org/integration/autoland/rev/e1251be93fcb
Part 2: Don't update null entries in the script GC things vector r=jandem

Comment 4

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/e773f946fcf4
https://hg.mozilla.org/mozilla-central/rev/e1251be93fcb