Principles and Methods to Verify OCaml Programs

ended

Deductive software verification, a subject within the broader field of formal methods, proposes a very ambitious path: to turn the correctness of a computer program into a mathematical statement, and then prove it. This project aims to develop a deductive verification framework, with a clear focus on proof automation, that directly tackles the verification of OCaml-written programs. OCaml seems to be particularly good target for verification. On one hand, it is the language of choice for the implementation of sensible software such as proof assistants, automated solvers, and compilers. On the other hand, OCaml is a multi-paradigm language, supporting both the functional and imperative paradigm, one can write clean, concise, type-safe, and efficient code. Yet, a verification tool that can handle hand-written code and is mostly automated does not currently exist. OCaml programmers must chose between proof automation, with the price of learning and programming in a verification-aware language, and then perform code extraction, or tools that require manual proof assistance. The Cameleer project aims to remedy this situation by providing the tools and principles for the verification of OCaml programs. The main outcome of this project is a powerful, usable, and mostly automated verification framework for the OCaml-written code. This will be a major step towards making verification more accessible to OCaml programmers, even in case they are not verification experts. The Cameleer framework will feature a translation of OCaml programs annotated with specifications written in GOSPEL, a recently proposed specification language, to different intermediate verification languages, namely WhyML, Viper, and Coq. This coexistence of multiple intermediate verification infrastructures allows the devised framework to target the verification of a large subset of OCaml programs, while combining the strengths of each individual intermediate language to obtain better verification results.