Raw Pointer Rewriting with LLMs for Translating C to Safer Rust
Yifei Gao, Chengpeng Wang, Pengxiang Huang, Xuwei Liu, Mingwei Zheng, Xiangyu Zhang · 2026
There has been a growing interest in translating C code to Rust due to Rust's robust memory and thread safety guarantees.Tools such as C2RUST enable syntax-guided transpilation from C to semantically equivalent Rust code.However, the resulting Rust programs often rely heavily on unsafe constructs, particularly raw pointers, which undermines Rust's safety guarantees.This paper aims to improve the memory safety of Rust programs generated by C2RUST by eliminating raw pointers.Specifically, we propose a raw pointer rewriting technique that lifts raw pointers in individual functions to appropriate Rust data structures.Technically, PR 2 employs decision-treebased prompting to guide the pointer lifting process.It also leverages code change analysis to guide the repair of errors introduced during rewriting, effectively addressing errors encountered during compilation and test case execution.We implement PR 2 and evaluate it using gpt-4o-mini on 28 real-world C projects.It is shown that PR 2 successfully eliminates 18.57% of local raw pointers across these projects, significantly enhancing the safety of the translated Rust code.On average, PR 2 completes the transformation of a project in 5.02 hours, at a cost of $1.13.Our code is available at https://github.com/bhcsayx/PR2.