The use of program dependence graphs in software engineering

This paper describes a language-independent program representation-the program dependence graph-and discusses how program dependence graphs, together with operations such as program slicing, can provide the basis for powerful programmmg tools that address important software-engineering problems, such as understanding what an existing program does and how it works, understanding the differences between several versions of a program, and creating new programs by combining pieces of old pro- grams. The paper primarily surveys work in this area that has been carried out at the University of Wisconsin during the past five years.