[jcranmer]

As far why it's not accidental, one of the primary purposes of DWARF is to be able to essentially describe "this source-level value is described by f(memory, registers)". Even if you wanted to restrict it to just the simple conditions like "this is described at stack offset N", there are cases where there might be variably-sized objects on the stack, and so you'd need to run a small function just to compute "N".