Harden a few assertions in GC sweep

[Filip Pizlo]

Patch forthcoming.

[Filip Pizlo]

Created attachment 328937 [details]
the patch

[Saam Barati]

Comment on attachment 328937 [details]
the patch

View in context: https://bugs.webkit.org/attachment.cgi?id=328937&action=review

> Source/JavaScriptCore/heap/MarkedBlock.cpp:405
> +    RELEASE_ASSERT(!m_isFreeListed);

The old branch was never taken?

[Filip Pizlo]

(In reply to Saam Barati from comment #2)
> Comment on attachment 328937 [details]
> the patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=328937&action=review
> 
> > Source/JavaScriptCore/heap/MarkedBlock.cpp:405
> > +    RELEASE_ASSERT(!m_isFreeListed);
> 
> The old branch was never taken?

Nope.  It doesn't make sense that m_isFreeListed would be true, and if it was, simply returning couldn't possibly be the right thing to do.

My best theory is this: this was landed originally in a patch where I had added that logic to support something else, and then removed that something else, but didn't remove the check.

[Filip Pizlo]

Landed in https://trac.webkit.org/changeset/225734/webkit

[Radar WebKit Bug Importer]

<rdar://problem/35958652>