How Accurate Is Coarse-grained Clone Detection?: Comparision with Fine-grained Detectors

Research on clone detection has been quite successful over the past two decades, which produced a number of state-of-the-art clone detectors. However, it has been still challenging to detect clones, even with such successful detectors, across multiple projects or on thousands of revisions of code in limited time. A simple and coarse-grained detector will be an alternative of detectors using fine- grained analysis. It will drastically reduce time required for detection although it may miss some of clones that fine-grained detectors can detect. Hence, it should be adequate for a tentative analysis of clones if it has an acceptable accuracy. However, it is not clear how accurate such a coarse-grained approach is. This paper evaluates the accuracy of a coarse-grained clone detector compared with some fine-grained clone detectors. Our experiment provides an empirical evidence about acceptable accuracy of such a coarse-grained approach. Thus, we conclude that coarse-grained detection is adequate to make a summary of clone analysis and to be a starter of detailed analysis including manual inspections and bug detection.