[webkit-reviews] review granted: [Bug 226146] [JSC] Add JIT ICs for `#x in obj` feature : [Attachment 431734] Patch

[bugzilla-daemon at webkit.org]

Saam Barati <sbarati at apple.com> has granted Ross Kirsling
<ross.kirsling at sony.com>'s request for review:
Bug 226146: [JSC] Add JIT ICs for `#x in obj` feature
https://bugs.webkit.org/show_bug.cgi?id=226146

Attachment 431734: Patch

https://bugs.webkit.org/attachment.cgi?id=431734&action=review




--- Comment #10 from Saam Barati <sbarati at apple.com> ---
Comment on attachment 431734
  --> https://bugs.webkit.org/attachment.cgi?id=431734
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=431734&action=review

Nice. r=me

> Source/JavaScriptCore/jit/Repatch.cpp:1083
> +	   InlineCacheAction action = actionForCell(vm, base);

Do we care about Structure::propertyAccessesAreCacheable for has private brand
semantics?

I also wonder if we care about uncacheable dictionary. It looks like
setPrivateBrand will always transition.

Not sure if we really care about those cases or not.

My hunch is: we don't care about Structure::propertyAccessesAreCacheable, but
we probably shouldn't rely on UncacheableDictionary not transitioning. That
said, I don't see in our current implementation how we could do it without
always transitioning given that we rely on the m_parentBrand pointer.