RulER: Automated Rule-Based Semantic Error Localization and Repair for Code Translation

Automated code translation aims to convert programs between different programming languages while maintaining their functionality. Due to the imperfections of code translation models, the generated translations may contain errors that compromise their reliability. Existing automated debugging methods for code translation rely on code alignments and repair patch templates to locate and fix erroneous translations. However, existing methods lack reliable references to construct code alignments and design repair patch templates, which significantly impacts their localization accuracy and repair effectiveness. To address these limitations, we reintroduce code translation rules and propose a rule-based debugging method for code translation, called RulER. RulER automatically derives code translation rules from correct translations generated by LLMs, enabling the efficient collection of diverse translation rules. In addition, RulER dynamically combines the existing rules on expandable nodes like expressions and tokens to further adaptively align more statements. These rules capture clear and detailed structural correspondences between source and target programming languages. Therefore, they can serve as reliable and reusable references for code alignment and repair template design, enabling RulER to locate and fix translation errors effectively. Our evaluation of RulER on Java-to-C++ and Python-to-C++ translations produced by four code translation models demonstrates that RulER outperforms state-of-the-art methods, BatFix and TransMap. Our experimental results show that RulER outperformed the best baseline by 20% and 272% in terms of error localization rates and repair success rates, respectively. RulER exhibits superior repair performance compared to directly prompting LLMs for patch generation, demonstrating a promising methodology for extracting and leveraging coding knowledge from LLMs.