Tiny machine...

   I have a very simple and tiny processor. It doesn't support
procedule call. Do I still need to add the code about TargetFrameInfo
and implement the stack operations in the XXXRegisterInfo.cpp???


Those operations are largly to codegen spill code. This means that even without calls you will need them.

In practice, however, I would just implement them as "assert(0 && "FOO method not implemented yet");" and only implement them when you find that they are being called.