If you’ve got an M1 Mac you might have noticed that when you run Xcode in native Apple Silicon mode, when building for the simulator it’ll use the arm64 ARCH. This is good, except if you’ve got a lot of legacy dependencies that haven’t been updated to support XCFrameworks. Most binary dependencies out there still assume SDK = iphonesimulator means ARCH = x86_64, which will result in linker errors.

One simple fix is to simply run Xcode in Rosetta. This will make it act just like you’re still on an Intel Mac, and the Simulator will build for x86_64. However doing this means you miss out on some of that legendary Apple Silicon compile performance.

To workaround this, you can basically force your project to cross-compile when using the iphonesimulator SDK to the x86_64 ARCH.

## Xcconfig

If you’re using .xcconfig files, simply add this to your common .xcconfig if you’ve got one, or into all your .xcconfig files otherwise:

ARCHS[sdk=iphonesimulator*] = x86_64


## Project Settings

If you’re not using .xcconfig, you should think about starting, otherwise you can manually edit your project’s Build Settings. Click on your Project in the navigatory, make sure the project is selected under PROJECT and not a TARGET, then go to Build Settings. Make sure you’ve got “All” settings selected so you can see the relevant setting.

Under Architectures, expand it until you can see Debug and Release, and another configurations your project has. Now next to the Debug and Release when you hover over you’ll see a +. Press this, and change the drop down to Any iOS Simulator SDK. Now, change the setting to Other, and type in x86_64. Repeat this for every configuration. Your Build Settings editor should look like the above.

## CocoaPods

If you’re using CocoaPods then the Pods.xcodeproj it generates will also need these Build Settings applied. Thankfully you can make one small amendment to your Podfile to make it apply for all your dependencies.

Now simply re-run pod install and it should apply the new Build Setting across all your Pods!

## Conclusion

It’s not necessary to run all of Xcode and its compilers in Rosetta to continue to use Simulators built for Intel, you can force the compilers to always build for x86_64 and Rosetta and the Simulator are smart enough to only run your app’s process in Rosetta. This allows us to reap the benefits of Apple Silicon on our development machines today while still giving our dependencies time to get their act together and adopt XCFrameworks and rebuild for iphonesimulator-arm64.