Re: virtualisation again?
Um, no. LLVM is a compiler technology that abstracts away the underlying assembly language of the platform. macOS has been native x86 since the transition. Nor is it pure Mach, opting more for a hybrid approach to a kernel.
LLVM isn't even platform-independent. It simply treats function calls and φ-operations as primitives during code generation. That the bytecode can be interpreted rather than translated to the targeted assembly is a happy accident, not a goal of the project.