More Like this

1. SLACC: Simion-based Language Agnostic Code Clones

   https://doi.org/10.1145/3377811.3380407  

   Mathew, George; Parnin, Christopher; Stolee, Kathryn T. (July 2020, International Conference on Software Engineering (ICSE))

   Successful cross-language clone detection could enable researchers and developers to create robust language migration tools, facilitate learning additional programming languages once one is mastered, and promote reuse of code snippets over a broader codebase. How- ever, identifying cross-language clones presents special challenges to the clone detection problem. A lack of common underlying rep- resentation between arbitrary languages means detecting clones requires one of the following solutions: 1) a static analysis frame- work replicated across each targeted language with annotations matching language features across all languages, or 2) a dynamic analysis framework that detects clones based on runtime behavior. In this work, we demonstrate the feasibility of the latter solution, a dynamic analysis approach called SLACC for cross-language clone detection. Like prior clone detection techniques, we use input/out- put behavior to match clones, though we overcome limitations of prior work by amplifying the number of inputs and covering more data types; and as a result, achieve better clusters than prior at- tempts. Since clusters are generated based on input/output behav- ior, SLACC supports cross-language clone detection. As an added challenge, we target a static typed language, Java, and a dynamic typed language, Python. Compared to HitoshiIO, a recent clone de- tection tool for Java, SLACC retrieves 6 times as many clusters and has higher precision (86.7% vs. 30.7%). This is the first work to perform clone detection for dynamic typed languages (precision = 87.3%) and the first to perform clone detection across languages that lack a common underlying repre- sentation (precision = 94.1%). It provides a first step towards the larger goal of scalable language migration tools. 

   more » « less
2. Pyclone: A Python Code Clone Test Bank Generator

   https://doi.org/10.1007/978-981-33-6385-4_22  

   Duncan, S.; Walke, r A.; DeHaan, C.; Alvord, S.; Cerny, T; Tisnovsky, P (April 2021, Information Science and Applications. Lecture Notes in Electrical Engineering)

   null; null; null (Ed.)

   Code clones are fragments of code that are duplicated in the codebase of an application. They create problems with maintainability, duplicate buggy code, and increase the size of the repository. To combat these issues, there currently exists a multitude of programs to detect duplicated code segments. However, there are not many varieties of languages among the benchmarks for code clone detection tools. Without covering enough languages for modern software development, the development of code-clone detection tools remains stunted. This paper describes a novel tool that will take a seed of Python source code and generate Type 1, 2, and 3 code clones in Python. As one of the most used and rapidly-growing languages in modern software development, our testbed will provide the opportunity for Python code-clone detection tools to be developed and tested. 

   more » « less
3. TECCD: A Tree Embedding Approach for Code Clone Detection

   https://doi.org/10.1109/ICSME.2019.00025  

   Gao, Yi; Wang, Zan; Liu, Shuang; Yang, Lin; Sang, Wei; Cai, Yuanfang (September 2019, IEEE International Conference on Software Maintenance and Evolution (ICSME))

   Clone detection techniques have been explored for decades. Recently, deep learning techniques has been adopted to improve the code representation capability, and improve the state-of-the-art in code clone detection. These approaches usually require a transformation from AST to binary tree to incorporate syntactical information, which introduces overheads. Moreover, these approaches conduct term-embedding, which requires large training datasets. In this paper, we introduce a tree embedding technique to conduct clone detection. Our approach first conducts tree embedding to obtain a node vector for each intermediate node in the AST, which captures the structure information of ASTs. Then we compose a tree vector from its involving node vectors using a lightweight method. Lastly Euclidean distances between tree vectors are measured to determine code clones. We implement our approach in a tool called TECCD and conduct an evaluation using the BigCloneBench (BCB) and 7 other large scale Java projects. The results show that our approach achieves good accuracy and recall and outperforms existing approaches. 

   more » « less
4. An empirical study of code clones: Density, entropy, and patterns

   https://doi.org/10.1016/j.scico.2024.103259  

   Hu, Bin; Yu, Dongjin; Wu, Yijian; Hu, Tianyi; Cai, Yuanfang (May 2025, Science of Computer Programming)

   In recent years, there has been a growing consensus among researchers regarding the dual nature of code clones. While some instances of code are valuable for reuse or extraction as components, the utilization of specific code segments can pose significant maintenance challenges for developers. Consequently, the judicious management of code clones has emerged as a pivotal solution to address these issues. Nevertheless, it remains critical to ascertain the number of code clones within a project, and identify components where code clones are more concentrated. In this paper, we introduce three novel metrics, namely Clone Distribution, Clone Density, and Clone Entropy (the dispersion of code clone within a project), for the quantification and characterization of code clones. We have formulated associated mathematical expressions to precisely represent these code clone metrics. We collected a dataset covering three different domains of Java projects, formulated research questions for the proposed three metrics, conducted a large-scale empirical study, and provided detailed numerical statistics. Furthermore, we have introduced a novel clone visualization approach, which effectively portrays Clone Distribution and Clone Density. Developers can leverage this approach to efficiently identify target clones. By reviewing clone code concerning its distribution, we have identified nine distinct code clone patterns and summarized specific clone management strategies that have the potential to enhance the efficiency of clone management practices. Our experiments demonstrate that the proposed code clone metrics provide valuable insights into the nature of code clones, and the visualization approach assists developers in inspecting and summarizing clone code patterns. 

   more » « less
5. Identifying Functionally Similar Code in Complex Codebases

   Su, Fang-Hsiang; Bell, Jonathan; Kaiser, Gail; Sethumadhavan, Simha (May 2016, 24th IEEE International Conference on Program Comprehension (ICPC))

   Identifying similar code in software systems can assist many software engineering tasks such as program understanding and software refactoring. While most approaches focus on identifying code that looks alike, some techniques aim at detecting code that functions alike. Detecting these functional clones - code that functions alike - in object oriented languages remains an open question because of the difficulty in exposing and comparing programs' functionality effectively. We propose a novel technique, In-Vivo Clone Detection, that detects functional clones in arbitrary programs by identifying and mining their inputs and outputs. The key insight is to use existing workloads to execute programs and then measure functional similarities between programs based on their inputs and outputs, which mitigates the problems in object oriented languages reported by prior work. We implement such technique in our system, HitoshiIO, which is open source and freely available. Our experimental results show that HitoshiIO detects more than 800 functional clones across a corpus of 118 projects. In a random sample of the detected clones, HitoshiIO achieves 68+% true positive rate with only 15% false positive rate. 

   more » « less