I completely agree. It's fairly simple to isolate and sandbox individual compiler processes in the cloud and fully mitigate this risk. You can be sure that what

I completely agree. It's fairly simple to isolate and sandbox individual compiler processes in the cloud and fully mitigate this risk. You can be sure that whatever processes the bitcode on Apple's servers is only supposed to touch a very limited number of files, syscalls, etc. If any cloud instance deviates from that norm, it should be trivial to detect that deviation. So, yes, I would probably try and submit malformed bitcode to Apple if I wanted to be a jerk... but I think Apple has probably thought of this too given how incredibly obvious it is.