1167468 - Assert that JSCompartment::objectMetadataTable never holds wrappers

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jim Blandy :jimb]

Attachment: Assert that JSObjects and their metadata are always in the same compartment.

Comment 1

[Jim Blandy :jimb]

Try push:
https://treeherder.mozilla.org/#/jobs?repo=try&revision=16e8fd6456f6

Comment 2

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

Comment on attachment 8609111 [details] [diff] [review]
Assert that JSObjects and their metadata are always in the same compartment.

Review of attachment 8609111 [details] [diff] [review]:
-----------------------------------------------------------------

Awesome, thanks!

::: js/src/jscompartment.cpp
@@ +724,3 @@
>  
>      if (JSObject* metadata = objectMetadataCallback(cx, obj)) {
> +        MOZ_ASSERT(this == metadata->compartment());

Is there a reason why we aren't using assertSameCompartment for these checks (and the existing one)? When should I prefer one over the other?

Comment 3

[Jim Blandy :jimb]

(In reply to Nick Fitzgerald [:fitzgen][:nf] from comment #2)
> Is there a reason why we aren't using assertSameCompartment for these checks
> (and the existing one)? When should I prefer one over the other?

I was just blindly imitating what I saw around me; assertSameCompartment is almost certainly better. I've changed the patch.

Comment 4

[Jim Blandy :jimb]

That last try push was a total mess for extraneous reasons, so here's another attempt:
https://treeherder.mozilla.org/#/jobs?repo=try&revision=46dc3f9580a0

I've also added an assertion that DebuggerObject_getAllocationSite never retrieves a wrapper; I think we'd agreed to do that on IRC originally.

Comment 5

[Jim Blandy :jimb]

Attachment: Assert that JSObjects and their metadata are always in the same compartment. r=fitzgen

Revised patch.

Comment 6

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/86dfea345501

Comment 7

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

https://hg.mozilla.org/mozilla-central/rev/86dfea345501