title: Xcode 9 keeps indexing at 100% of CPU
body: <p>I have a project (objective C) that keeps being indexed by Xcode 9.2, and uses 100% of the CPU for hours.
  Each time I quit Xcode, and restart, it starts to index again from scratch, even if NONE of the files has been modified. Are we serious about this?</p>
  
  <p>I have the same project ported on Android Studio, and indexing is working fine.</p>
  
  <p>It's not like it's new, Xcode has an indexing problem since ever, but seriously, we're talking about Xcode version 9, and it's worse than ever...</p>
  
  <p>I've tried to remove pieces of my code, but's it's very difficult to investigate, I have to wait minutes to evaluate if it impacted the indexing, and it's very difficult to be sure. And of course I deactivated indexing, but no more code completion.
  Totally discouraged by this, as I have the feeling nothing will fix it.</p>