Understanding Bugs in Rust Compilers

Rust compilers play a foundational role in the Rust language. Like any complex system, they are susceptible to bugs, which can impact the correctness and reliability of the compiled Rust programs. To gain a deeper understanding of these bugs, this paper presents the first comprehensive analysis of historical bugs in two widely used Rust compilers: Rustc and Rust-GCC. The analysis delves into the bugs’ characteristics, bug-proneness locations, bug root causes, and bug-fixing efforts. The findings reveal that the majority of bugs in Rustc are associated with the compiler’s kernel, while Rust-GCC experiences most bugs related to the cleanup process. Among all modules, the ‘src/librustc’ module exhibits the highest bug-proneness in the Rustc compiler, whereas the ‘gcc/rust’ modules demonstrate the highest bug-proneness in the Rust-GCC compiler. Furthermore, the study reveals that the bug-fixing process is accelerated when test cases utilize Rust’s concurrency features.