1135827 - js::SavedStacks::insertFrames roots more than necessary

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jim Blandy :jimb]

The use of AutoLookupRooter here seems to be unnecessary:

https://hg.mozilla.org/mozilla-central/file/360b5f211180/js/src/vm/SavedStacks.cpp#l629

The AutoLookupRooter ensures that its referent's 'trace' method is called when needed. However, the AutoLookupRooter's referent is always an element of stackChain; since that's an AutoLookupVector, it's already rooting its elements.

Nothing bad should come from calling a 'trace' method twice, so this is more a "bit of disorder" than a "bug". I just wanted to call it out.

Comment 1

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

Attachment: Don't root more times than necessary in js::SavedStacks::insertFrames

Comment 2

[Jim Blandy :jimb]

Comment on attachment 8568658 [details] [diff] [review]
Don't root more times than necessary in js::SavedStacks::insertFrames

Review of attachment 8568658 [details] [diff] [review]:
-----------------------------------------------------------------

Yay.

Comment 3

[Nick Fitzgerald [:fitzgen] [⏰PST; UTC-8]]

Try push: https://treeherder.mozilla.org/#/jobs?repo=try&revision=5fc7beb07dcc

Comment 4

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/5ad6b7250af0

Comment 5

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/5ad6b7250af0