C++20 Modules replace C++'s traditional textual inclusion model with a compiled module interface. Instead of repeatedly preprocessing the same headers in every translation unit, consumers explicitly import the interface they depend on. No more header...

What happens to a register when you call a function? On AArch64, the answer isn't "the CPU saves it." When you call a function, the CPU doesn't look at a register table and decide what to preserve. BL doesn't know about caller-saved or callee-saved ...