944491 - Add null-checking asserts to GetGCThingRuntime and GetGCThingMarkBitmap

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Andrew McCreight [:mccr8]]

While working on bug 942528, I was getting weird near-NULL crashes in ExposeObjectToActiveJS, which I think was from passing in NULL pointers.  I can imagine calling GetGCThingRuntime on a null pointer results in something bad, so I think it would be useful to add a null checking assert to it.

Comment 1

[Andrew McCreight [:mccr8]]

Attachment: Add null-checking assert to GetGCThingRuntime. r=jonco

Comment 2

[Jon Coppeard (:jonco)]

Comment on attachment 8340084 [details] [diff] [review]
Add null-checking assert to GetGCThingRuntime. r=jonco

Review of attachment 8340084 [details] [diff] [review]:
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Fair enough, it would be more obvious what went wrong if we had this assertion.

While you're there, can you add one to GetGCThingMarkBitmap() above too?

Comment 3

[Andrew McCreight [:mccr8]]

Yeah, good point.  For some reason I'd convinced myself that we'd hit other null check guards before we called that method, but that's not actually the case.

https://hg.mozilla.org/integration/mozilla-inbound/rev/c120711ba3ca

Comment 4

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/c120711ba3ca