Identifying Similar Code with Program Dependence Graphs

We present an approach to identify similar code in programs based on finding similar subgraphs in attributed directed graphs. This approach is used on program dependence graphs and therefore considers not only the syntactic structure of programs but also the data flow within (as an abstraction of the semantics). As a result, there is no tradeoff between precision and recall - our approach is very good in both. An evaluation of our prototype implementation shows that our approach is feasible and gives very good results despite the non polynomial complexity of the problem.