// will be when machine code is emitted.
func BuildFuncDebug(ctxt *obj.Link, f *Func, loggingLevel int, stackOffset func(LocalSlot) int32, rval *FuncDebug) {
	if f.RegAlloc == nil {
		f.Fatalf("BuildFuncDebug on func %v that has not been fully processed", f)
	}
	state := &f.Cache.debugState
	state.loggingLevel = loggingLevel % 1000

	// A specific number demands exactly that many iterations. Under