Bug 144721 – Worker threads leak WeakBlocks (as seen on leaks bot)

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Andreas Kling]

<rdar://problem/20848288>

We've got about 750 KB worth of WeakBlocks leaked on the leaks bot right now. Boo.

[Andreas Kling]

Created attachment 252547 [details]
Patch

[Darin Adler]

Comment on attachment 252547 [details]
Patch

I think we return here and use std::unique_ptr for this. It would remove the need to explicitly call WeakBlock::destroy in Heap::sweepNextLogicallyEmptyWeakBlock. I know this is low-level code and std::unique_ptr might seem out of place, but I think it would cleanly prevent a mistake like this one!

[Andreas Kling]

(In reply to comment #2)
> Comment on attachment 252547 [details]
> Patch
> 
> I think we return here and use std::unique_ptr for this. It would remove the
> need to explicitly call WeakBlock::destroy in
> Heap::sweepNextLogicallyEmptyWeakBlock. I know this is low-level code and
> std::unique_ptr might seem out of place, but I think it would cleanly
> prevent a mistake like this one!

That's not a bad idea. I glossed over it because I assumed WeakBlocks were aligned to their block size, but it turns out that they're just plain fastMalloc()'ed objects.

With a little care, we can fix these up to live in unique_ptr. Landing this right away to unscrew leaks bot though.

[Geoffrey Garen]

> I think we return here and use std::unique_ptr for this. It would remove the
> need to explicitly call WeakBlock::destroy in
> Heap::sweepNextLogicallyEmptyWeakBlock. I know this is low-level code and
> std::unique_ptr might seem out of place, but I think it would cleanly
> prevent a mistake like this one!

I agree. Once upon a time it was not practical to unique_ptr these objects, but now it should be pretty trivial.

[WebKit Commit Bot]

Comment on attachment 252547 [details]
Patch

Clearing flags on attachment: 252547

Committed r183938: <http://trac.webkit.org/changeset/183938>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.