Xcode 8 Stuck at Indexing and uses up all free space in the storage

I am a Unreal C++ Developer and I'm using Xcode as my primary editor for my Unreal projects. Everything was fine with Xcode 7.3.1. Yesterday, I upgraded Xcode from 7.3.1 to 8.0. While opening Unreal Projects in Xcode 8, Xcode freezes at Indexing and also free space on Macintosh SSD is used up drastically by Xcode or whatever(I don't know since the SSD space is completely used up hence I can't even close any running applications. It just freezes). I tried,

Deleting everything in "Derived Cache/" folder and rebooting Mac
Re generating Xcode project from Unreal Editor
Emptying out build folder and started rebuilding from scratch.
Re installing Xcode 8

Please note that it is not the problem of low space or out of memory.

Because I've more than 100 GB free and 8 GB RAM. But the problem is the free space is used up so fast like several GB's per second! I can't even imagine Xcode or my SSD will have write speed like that. And it is specifically for Unreal Projects alone.

But nothing seems to work out. Any help would be appreciated.

Solution

After some investigation version 4.13.0 and 4.13.1 of Unreal triggers that index bug in Xcode 8.

I uninstalled Xcode (drag to Trash from Applications) then downgraded to Xcode 7.3.1 via downloading from the "more" section of the Apple developer site.

Then re-setup and regenerated the Engine source with Xcode 7.3.1 installed. Then I regenerated my C++ project files again too.

After that I could open up project in XCode. It still took a while to index, but the memory never spiked more than 1.3 gig while I was watching it. Left it going over night and it had finished in the morning without filling up my HD.

From what I heard there is a fix in XCode 8.1 - but at the time of writing this answer that had not yet been released.