An implementation of and experiment with semantic differencing

Software maintainers face a wide range of difficult tasks including impact analysis and regression testing. Understanding semantic relationships, such as the semantic cohesiveness in a program or the semantic differences between two programs, can help a maintainer address these problems. However, semantic analysis is a difficult problem. For example, few semantic differencing algorithms and even fewer implementations exist. The first semantic differencing implementation for the C language is presented and studied. A large collection of semantic differences of 10 programs are computed. The average size reduction was 37.70%. The study presented illustrates the practicality of semantics differencing. Finally, the application of semantic differencing in the area of program testing and impact analysis is considered.