Insert conversion code that reconstructs the original function argument
types from the legalized ABI signature.
Add abi::legalize_abi_value(). This function is used when adapting code
to a legalized function signature.
Add an abi module with code that is probably useful to all ISAs when
implementing this function.
Add a unit() method to RegClassData which can be used to index the
register units in a class.
This entry point will be used for controlling ABI conventions when
legalizing.
Provide an empty implementation for RISC-V and let the other ISAs crash
in legalization.
This is just the scaffolding. We still need to:
- Rewrite the entry block arguments to match the legalized signature.
- Rewrite call and return instructions.
- Implement the legalize_signature() function for all ISAs.
- Add shared generic types to help with the legalize_signature()
functions.
