When I incorporated a popular OAuth2 library in iOS called OAuth2Client to my iOS app which is developed on Xcode 7 Beta 2 and then tried running the simulator, the following error occurred and the simulator didn't launch.
Unsupported compiler 'com.apple.compilers.llvm.clang.1_0' selected for architecture 'x86_64'
What does this error mean? A lot of warnings (yellow triangle) followed with the error above (red octagon), such as:
warning: no rule to process file '/Users/myUsername/myAppname/Pods/NXOAuth2Client/Sources/NSData+NXOAuth2.m' of type sourcecode.c.objc for architecture x86_64
How can I deal with the these errors and run the simulator properly? Or does CocoaPods only work on environments prior to Xcode 7 Beta?
UPDATE
Later I found that this occurs on any projects I create, not only on a project using CocoaPods. The only clue that occurs to me is that when I updated my iTunes to 12.2 today and then launched my Xcode, the dialog popped up, instructing to install new command-line tools.
UPDATE 2
I just upgrade to Xcode 7 Beta 3 but the error still got me annoyed...
I met the same issue on Xcode 7 beta 4. I have tried to clean the project for several times but with no lucky. Unbelievably, restart Xcode saved my night. You can try this.
Solution 1
Close Xcode, open terminal, before anything else, type: “defaults delete com.apple.dt.Xcode” (this addresses your Xcode settings) open Xcode and your project should work normally.
Plan B
If that doesn't work try this to clear out your cache. Save your files then put this in your terminal:
rm -rf Library/Caches/com.apple.dt.Xcode/
Potential causes
This bug can occur if you declared your pods with single quotes instead of double quotes or for some reason your pod files become corrupted (i.e.: working with p.lists, Google's p.list, firebase etc). I think what triggers the bug to break your code is during certain recompiling phases, for example: opening after unzipping the project, or opening the project after pulling it from GitHub.
With the version (X-code 8 beta 2) I got the following error, because I tried to run it out of the downloads folder:
Unsupported compiler 'com.apple.compilers.llvm.clang.1_0' selected for architecture 'x86_64'
It helped to put it in the normal Program Folder!
Angel's answer worked for me as well. I too experienced this with 8b2, Moving the app to the Program folder instead running out of Downloads resolved it for me.
In my case with XCode 9.0.1, I noticed that even after closing XCode, I had stuck processes running from an earlier version of XCode running:
$ ps aux | grep Xcode
dyoung 83871 0.0 0.0 2547420 708 s000 S Tue11PM 0:00.19 /Applications/Xcode.app/Contents/SharedFrameworks/DVTInstrumentsFoundation.framework/Resources/DTServiceHub
dyoung 28009 0.0 0.0 2432804 796 s012 S+ 10:24AM 0:00.00 grep Xcode
dyoung 27996 0.0 0.3 2869796 46088 ?? S 10:23AM 0:00.65 /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Library/Xcode/Overlays/Interface Builder Cocoa Touch Tool --hostToRemoteFIFO /var/folders/k6/80v30vf13kdc8qd2rjtq35640000gn/T/ibtoold-27980/IB/BF1AA7D2-8B3F-4157-A447-6D700B84C105.HostToRemote --remoteToHostFIFO /var/folders/k6/80v30vf13kdc8qd2rjtq35640000gn/T/ibtoold-27980/IB/BF1AA7D2-8B3F-4157-A447-6D700B84C105.RemoteToHost
dyoung 27995 0.0 0.3 2869796 46060 ?? S 10:23AM 0:00.60 /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Library/Xcode/Overlays/Interface Builder Cocoa Touch Tool --hostToRemoteFIFO /var/folders/k6/80v30vf13kdc8qd2rjtq35640000gn/T/ibtoold-27982/IB/2DC08948-3951-4E09-BBC0-CC4C27712A9C.HostToRemote --remoteToHostFIFO /var/folders/k6/80v30vf13kdc8qd2rjtq35640000gn/T/ibtoold-27982/IB/2DC08948-3951-4E09-BBC0-CC4C27712A9C.RemoteToHost
dyoung 27994 0.0 0.3 2869796 46076 ?? S 10:23AM 0:00.62 /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/Library/Xcode/Overlays/Interface Builder Cocoa Touch Tool --hostToRemoteFIFO /var/folders/k6/80v30vf13kdc8qd2rjtq35640000gn/T/ibtoold-27981/IB/DB22227E-FBD5-46B9-B90D-FF440135ABEC.HostToRemote --remoteToHostFIFO /var/folders/k6/80v30vf13kdc8qd2rjtq35640000gn/T/ibtoold-27981/IB/DB22227E-FBD5-46B9-B90D-FF440135ABEC.RemoteToHost
dyoung 27982 0.0 0.5 3830728 84644 ?? Ss 10:23AM 0:01.22 /Applications/Xcode.app/Contents/Developer/usr/bin/ibtoold --sending-client-environment
dyoung 27981 0.0 0.5 3829860 84672 ?? Ss 10:23AM 0:01.20 /Applications/Xcode.app/Contents/Developer/usr/bin/ibtoold --sending-client-environment
dyoung 27980 0.0 0.6 3842552 94472 ?? Ss 10:23AM 0:01.67 /Applications/Xcode.app/Contents/Developer/usr/bin/ibtoold --sending-client-environment
One I manually killed all these processes then restarted XCode my compiler error magically went away.
Just use the option of "build for running" this solved my error. I'm using Xcode 8.3 beta_2 on Mac OS Sierra 10.12.3
来源：https://stackoverflow.com/questions/31152170/unsupported-compiler-com-apple-compilers-llvm-clang-1-0-selected-for-architect