Automatic code summarization aims to generate concise natural language descriptions (summary) for source code, which can free software developers from the heavy burden of manual commenting and software maintenance. Existing methods focus on learning a direct mapping from pure code to summaries, overlooking the significant heterogeneity gap between code and summary. Moreover, existing methods lack a human-like re-check process to evaluate whether the generated summaries match well with the code. To address these two limitations, we introduce RBCoSum, a novel framework that incorporates the generated Chain Of Comments (COC) as auxiliary intermediate information for the model to bridge the gap between code and summaries. Also, we propose a rethinking process where a learned ranker trained on our constructed ranking dataset scores the extent of matching between the generated summary and the code, selecting the highest-scoring summary to achieve a re-check process. We conduct extensive experiments to evaluate our approach and compare it with other automatic code summarization models as well as multiple code Large Language Models (LLMs). The experimental results show that RBCoSum is effective and outperforms baselines by a large margin. The human evaluation also proves the summaries generated with RBCoSum are more natural, informative, useful, and truthful.

Code generation aims to generate code in a general-purpose programming language, such as C++, based on natural language intents. Existing efforts primarily focus on relatively simple programming problems and fail to evaluate the thought process involved in complex programming scenarios. In this paper, we introduce “steps-guided code generation,” a task that assesses the quality of both thought steps and code implementation to evaluate the overall management of handling a complex programming problem. To support this task, we construct CodeStepsEval, a real-world scenario dataset of complex programming problems in the C++ programming language with varying levels of difficulty. Comprehensive experiments on this dataset demonstrate the importance of high-quality steps in enhancing code generation performance and the challenges faced by the code LLMs in this task.