How to map MachineInstr with IR

Does anyone know how to match the Machine Instruction to their corresponding IR Instruction (the MI object not abstract instruction)?

I’m tracking the virtual register and trying to find which IR it comes from. It’s easy to map virtual registers to MI but I can’t find how to map MI with IR now. I know LLVM makes this transformation by SelectionDAG, is there any references between them created when instruciton selection transform IR to MI? Or can I use some other interface, e.g. DebugInfo to make what I want?