1374033 - Optimize EndLimitedIterator::GetNext()

Status: RESOLVED FIXED

(Core :: XPCOM, enhancement)

Description

[(no longer active)]

I noticed this when profiling Speedometer Preact tests.  The bounds check in ElementAt() under GetNext() from <https://searchfox.org/mozilla-central/rev/b95a1a95838cc6e85ea5d9b9e3ae39b4cd69d8ef/dom/base/nsFrameMessageManager.cpp#924> shows up in profiles.

The comment there and the assertions show that the intention was for HasMore() to do the bounds check and not for another one here, but after bug 1159244 landed we forgot about this case and ended up with extra bounds checking.  I have a patch to remove this extra cost.

Comment 1

[(no longer active)]

Attachment: Remove double bounds checking from the next accessors of the iterator classes of nsTObserverArray

Comment 2

[Nathan Froyd [:froydnj]]

Comment on attachment 8878865 [details] [diff] [review]
Remove double bounds checking from the next accessors of the iterator classes of nsTObserverArray

Review of attachment 8878865 [details] [diff] [review]:
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This shows up in profiles?  Ugh.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/3b573b3cb047
Remove double bounds checking from the next accessors of the iterator classes of nsTObserverArray; r=froydnj

Comment 4

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/3b573b3cb047