Why is Xcode on my M1 Mac trying to build for `iOS Simulator-x86_64`? Why is it not building for an `arm` based simulator?

Question

I have an M1 MacBook Air.

When building for a simulator in Xcode, I am seeing the following warnings and errors:

ld: warning: ignoring file /Users/kon/Library/Developer/Xcode/DerivedData/InvisibleComputersApp-hktlnhvaoskvxkcdhnahydmbodzw/Build/Products/Debug-iphonesimulator/GoogleSignIn.o, building for iOS Simulator-x86_64 but attempting to link with file built for unknown-arm64
ld: warning: ignoring file /Users/kon/Library/Developer/Xcode/DerivedData/InvisibleComputersApp-hktlnhvaoskvxkcdhnahydmbodzw/Build/Products/Debug-iphonesimulator/AppAuth.o, building for iOS Simulator-x86_64 but attempting to link with file built for unknown-arm64
ld: warning: ignoring file 
/Users/kon/Library/Developer/Xcode/DerivedData/InvisibleComputersApp-hktlnhvaoskvxkcdhnahydmbodzw/Build/Products/Debug-iphonesimulator/GTMAppAuth.o, building for iOS Simulator-x86_64 but attempting to link with file built for unknown-arm64
ld: warning: ignoring file /Users/kon/Library/Developer/Xcode/DerivedData/InvisibleComputersApp-hktlnhvaoskvxkcdhnahydmbodzw/Build/Products/Debug-iphonesimulator/AppAuthCore.o, building for iOS Simulator-x86_64 but attempting to link with file built for unknown-arm64
ld: warning: ignoring file /Users/kon/Library/Developer/Xcode/DerivedData/InvisibleComputersApp-hktlnhvaoskvxkcdhnahydmbodzw/Build/Products/Debug-iphonesimulator/GTMSessionFetcherCore.o, building for iOS Simulator-x86_64 but attempting to link with file built for unknown-arm64
Undefined symbols for architecture x86_64:
  "_OBJC_CLASS_$_GIDConfiguration", referenced from:
      objc-class-ref in GlobalState.o
  "_OBJC_CLASS_$_GIDSignIn", referenced from:
      objc-class-ref in GoogleAuthService.o
      objc-class-ref in GoogleRefreshTokenService.o
      objc-class-ref in InvisibleComputersAppApp.o
  "_OBJC_CLASS_$_GIDSignInButton", referenced from:
      objc-class-ref in LoginView.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

This sounds to me like Xcode is somehow trying to build an x86 binary? Why is it even trying to do that, aren't the simulators arm based on the M1 Macs?

How can I

Stopped

Check project settings and .xcconfig files - probably there is there x86_64 architecture set. – Amphibology

@Amphibology what would this look like? – Stopped

Under "Architectures" it says "Standard Architectures (arm64, armv7) - $(ARCHIS STANDARD) – Stopped

Hey @Amphibology - yes, I found a settings. I had previously been following a stack overflow answer to disable ARM builds for simulator, due to some other issue... now after switching to an M1 Mac, this has bitten me. – Stopped

Got the same. Did you find out? – Stinkstone

Answer 1

I spent 3 days on this issue beating my head against the wall. Today, I finally cracked it and understood the problem.

I am working on a highly modular project with ~100 frameworks. When migrating from the X86_64 (Intel) architecture to arm64 (M1) I was always getting this error:

Could not find module 'MyModule' for target 'x86_64-apple-ios-simulator'; found: arm64-apple-ios-simulator, at /my/path/

when building natively on M1.

The reason is that the simulator runs natively on M1 but the simulated app runs still under Intel. That's why the x86_64 architecture was built in the first place.

The two architectures are now beating each other as the simulator is arm64 while the simulated app is X86_64. Removing the arm64 architecture for the pods and project settings fixed the issue and I can build the project entirely on M1 now.

Here are screenshots from the ActivityMonitor. AchieveMe is the app running in the simulator.

To fix the problem for Cocoapods you can simply do:

target.build_configurations.each do |config|
  config.build_settings['EXCLUDED_ARCHS[sdk=iphonesimulator*]'] = 'arm64'
end

I am using XcodeGen and there it can simply be added under debug configuration as:

YourSettings
...
configs:
      Debug:
        EXCLUDED_ARCHS[sdk=iphonesimulator*]: arm64

Best of luck, I hope it helps. I can sleep in peace now.

Checkup

Hello I'm trying to test my Unity game on Xcode. Unfortunately, Unity exports builds for iOS Simulator with x86_64 architecture and I'm currently on M1 Silicon Mac. If I understand correctly, Xcode on Silicon Mac only has arm64 Simulators. Is it still possible to test my x86_64 build? – Whensoever

Hi @A.Tikadze, with the latest Xcode 14.3 Apple shipped ARM64 so as X86_64 simulators, therefore you should be able to do that. You can enable it under Product -> Destination Architecture -> Show Both, then you will be able to select Rosetta simulator. Good luck there! – Checkup

Yep, I was able to do that Thanks – Whensoever

This is a useful workaround, thanks. The question I'm really hoping to find the answer for is how to get the simulated app to run under arm64 rather than x64. By the sounds of it, I just need to update Xcode to 14.3 (and select an arm64 destination)? – Enervate

Hi Andrew, yes, that is correct, I don't think you have any other option. – Checkup

Answer 2

You can try opening Xcode with "Open using Rosetta" check ON.

0. Quit Xcode
1. Go to your Applications folder
2. Right click Xcode then select "Get Info"
3. Check "Open using Rosetta"
4. Open Xcode

Sacerdotal

Running Xcode under Rosetta is not supported. Please fix the project to build x86_64 only instead of running under Rosetta. – Uncounted

Answer 3

If you have a dependency that does not support arm64, you can tell the build system to skip arm64 (this building x86_64) by adding "arm64" to the list of excluded architectures (EXCLUDED_ARCHS) in your targets' build settings.

Uncounted