<rdar://problem/24581488> LLDB does some deep recursion into external modules to resolve name lookups

I’ve been investing the “po performance bug” (<rdar://problem/24534599> po when debugging Xcode is extremely slow) in recent Xcode, and I discovered this problem.

We are looking at pch files that are generated on Xcode’s behalf and it looks like we’re recursing through their dependencies when we don’t find something, but we’re probably not searching efficiently because this is super slow.

This would be an Everest regression.

I’m going to keep working on the original Radar because I haven’t gotten Brent’s backtrace yet; that said, this one is going to affect users’ perception of expression parser performance as well so I’ve filed it separately.


Hi Sean,

Can you gave us some more context on this because without access to the referenced rdar bug I don’t really understand your previous e-mail (and I think I am not alone with this)


Is it related to the regression that Greg was talking about here: