Open-Source Tools and Benchmarks for Code-Clone Detection: Past, Present, and Future Trends

A fragment of source code that is identical or similar to another is a code-clone. Code-clones make it difficult to maintain applications as they create multiple points within the code that bugs must be fixed, new rules enforced, or design decisions imposed. As applications grow larger and larger, the pervasiveness of code-clones likewise grows. To face the code-clone related issues, many tools and algorithms have been proposed to find and document code-clones within an application. In this paper, we present the historical trends in code-clone detection tools to show how we arrived at the current implementations. We then present our results from a systematic mapping study on current (2009-2019) code-clone detection tools with regards to technique, open-source nature, and language coverage. Lastly, we propose future directions for code-clone detection tools. This paper provides the essentials to understanding the code-clone detection process and the current state-of-art solutions.