RUSTY: Effective C to Rust Conversion via Unstructured Control Specialization

Rust is an emerging programming language designed for both performance and security, and thus many research efforts have been conducted recently to migrate legacy code bases in C/C++ to Rust to exploit Rust's safety benefits. Unfortunately, prior studies on C to Rust conversion still have three limitations: 1) complex structure; 2) code explosion; and 3) poor performance. These limitations greatly affect the effectiveness and usefulness of such conversions. This paper presents Rusty, the first system for effective C to Rust code conversion via unstructured control specialization. The key technical insight of Rusty is to implement C-style syntactic sugars on top of Rust, thus eliminating the discrepancies between the two languages. We have implemented a software prototype for Rusty and conducted experiments to evaluate the effectiveness and testify the usefulness of it by applying Rusty to micro-benchmarks, as well as 3 real-world C projects: 1) Vim; 2) cURL; and 3) the silver searcher. And experimental results demonstrated that Rusty is effective in eliminating unstructured controls, reducing the code size by 16% on average with acceptable overhead (less than 61 microseconds per line of C code).