We don't currently have a way of writing unit tests for code in lib/CodeGen, and we do have some code that could benefit from having tests. (See r158310).
The problem is that you can't just create a MachineFunction test instance and start poking at it. You need to give it a target first, and certain helper classes like MachineRegisterInfo are also expected to be present.
I am looking for a volunteer to build the scaffolding required in unittests/CodeGen to make it possible to write unit tests for MachineFunction and associated classes. You would need to:
- Set up a unittests/CodeGen target that links in libCodeGen.
- Create a mock target with minimal functionality, preferably without depending on TableGen.
- Provide an easy way for individual tests to get a MachineFunction instance with the required decorations.
This would be a good way to learn about target and codegen configuration.