Hi,
This is the second minimal patch keeping Nios2 target buildable. I'm adding subtarget here and other stuff for frame lowering, instruction, register information methods. I do not add any test cases, as still there are missing parts like DAG selector and assembly printing. I plan to include them into the next patch.
Thanks,
Andrei.
Please don't have a default subtarget. There's no reason to do so and it just confuses things.