We have designed an intermediate language (IL) for the CakeML compiler that supports the verified, efficient compilation of functions and calls. Verified compilation steps include batching of multiple curried arguments, detecting calls to statically known functions, and specialising calls to known functions with no free variables. Finally, we verify the translation to a lower-level IL that only supports closed, first-order functions. These compilation steps resemble those found in other compilers (especially OCaml). Our contribution here is the design of the semantics of the IL, and the demonstration that our verification techniques over this semantics work well in practice at this scale. The entire development was carried out in the HOL4 theorem prover.

@article{OwensNKMT17,
  title = {Verifying efficient function calls in CakeML},
  author = {Scott Owens and Michael Norrish and Ramana Kumar and Magnus O. Myreen and Yong Kiam Tan},
  journal = {Proceedings of the ACM on Programming Languages},
  volume = {1},
  number = {ICFP},
  year = {2017},
  doi = {10.1145/3110262}
}