For me it just crashes Xcode as soon as I press the capture button. Xcode 12.0.1 is a trainwreck.

You probably misread my question. I am not looking for a unified address space. I am saying that the language extension to specify address space in function arguments is overqualified. In CUDA, if I pass a device or shared pointer to a function with just a blank pointer, the address space is inferred from the calling actual parameter. This is compiler problem, not a GPU driver LCD problem. The main issue with this is that you cannot use third party code without modifying *all* and every function header. Does this make sense now?