A SURVEY OF PROGRAM SLICING TECHNIQUES

A program slice consists of the parts of a program that (potentially) affect the values computed at some point of interest. Such a point of interest is referred to as a slicing criterion, and is typically speci fied by a location in the program in combination with a subset of the program's variables. The task of computing program slices is called pr ogram slicing. The original definition of a program slice was presente d by Weiser in 1979. Since then, various slightly different notions of program slices have been proposed, as well as a number of methods to compute them. An important distinction is that between a static and a dynamic slice. Static slices are computed without making assumptions r egarding a program's input, whereas the computation of dynamic slices relies on a specific test case. This survey presents an overview of pr ogram slicing, including the various general approaches used to comput e slices, as well as the specific techniques used to address a variety of language features such as procedures, unstructured control flow, c omposite data types and pointers, and concurrency. Static and dynamic slicing methods for each of these features are compared and classified in terms of their accuracy and efficiency. Moreover, the possibilitie s for combining solutions for different features are investigated. Rec ent work on the use of compiler-optimization and symbolic execution te chniques for obtaining more accurate slices is discussed. The paper co ncludes with an overview of the applications of program slicing, which include debugging, program integration, data flow testing, and softwa re maintenance.