Ho trovato questo post sul blog intitolato: Processo Fix TCCD che utilizza un elevato utilizzo della CPU quando si esegue Xcode .
estratto
Using Xcode 8 is really a frustrating experience. When compile swift source files or write code in Sierra(the latest macOS), Xcode frequently freeze. It's nuking productivity. After a long time of searching, I found this is caused by a process named tccd which take up to 70% of CPU usage. What is tccd? It seems to be a access controller that manage the permission to user's contacts. So the solution is quite easy, go to
System Preferences → Security & Privacy → Privacy → Contacts
uncheck Xcode and restart it. Then, it works again.
Quindi sembrerebbe, semplicemente disabilitando i contatti si disabiliterà tccd
facendo così cadere l'elevato carico della CPU.