Does Rust SPARK joy? : Recommendations for safe cross-language bindings between Rust and SPARK

Sammanfattning: This thesis aims to provide recommendations for interfacing two memory-safe programming languages, Rust and SPARK. The comparison of Rust and C/C++, as well as SPARK and C/C++, has been thoroughly researched. However, this level of investigation hasn’t been as extensive between memory-safe languages. SPARK is a subset of Ada, a programming language with a long track record in safety-critical applications. Rust is a multi-paradigm language that has gained popularity since its emergence roughly a decade ago. Both languages implement ownership systems and type safety, which are instrumental in developing safe and reliable software. Memory-safety bugs in code written in C/C++ account for about 70 % of major vulnerabilities in the industry, as reported by organizations such as Microsoft, Apple, and Google. While tools to avoid memory errors exist, code cannot be made safe retroactively, which creates a need for languages designed with safety in mind, such as Rust and SPARK. Combining those two languages is a very promising path for low-level and systems programming and safety-critical applications (automotive, avionics, medical etc.). This thesis identifies best practices for safe bindings between Rust and SPARK, focusing on ensuring memory safety, type safety, and ownership, and then analyzes how to maintain or transfer those properties. The thesis provides clear recommendations based on control study programs and a real-world example using BBQueue, a circular buffer library suitable for embedded systems implemented in both languages. The identified best practices can be used for safe bindings and automated tools/code generation. This thesis fills a gap in existing research, primarily focusing on combining safe and unsafe languages. It provides a valuable contribution to software security and safety-critical systems.