xcode 9.2 or 9.4 for CUDA 10 and macOS 10.13.6?

I’m getting a little turned around as to what I should actually be installing on a fresh 10.13.6 installation. The install guide for OSX gives conflicting version numbers:

  • XCode: 9.4
  • AppleLLVM: 9.0.0

According to this table 9.4 will give me AppleLLVM 9.1.0, which sounds incorrect since nvcc is particular about the version number: https://en.wikipedia.org/wiki/Xcode#Latest_versions

9.1.0 would presumably give this error message: https://devtalk.nvidia.com/default/topic/1032646/cuda-setup-and-installation/macos-10-13-4-and-xcode-9-3-compatibility-broken-with-cuda-toolkit-9-1/post/5255278/#5255278

A followup a little below advises installing 9.2: https://devtalk.nvidia.com/default/topic/1032646/cuda-setup-and-installation/macos-10-13-4-and-xcode-9-3-compatibility-broken-with-cuda-toolkit-9-1/post/5260119/#5260119

  1. Is this what people are doing (install 9.2)?
  2. Does nvcc check the XCode version, or only the CXX version (AppleLLVM version)?

If so, would it make sense to edit the install documentation to download XCode 9.2? My understanding reading online is xcode-select can be used to switch between stacks, but each download is ~5GB and it would be nice to know precisely which one to download. The version numbers for Windows and Linux make sense / are clear to know which compiler you will need, but the macOS version numbers are less straightforward.