The semantic approach to program slicing

Abstract

Program slicing is a source-to-source transformation that has applications in construction, analysis, testing and debugging of programs. A program slice contains the portion of a program that captures some subset of the program behavior. Algorithms are available for constructing slices for a particular execution of a program (dynamic slices) as well as to approximate a subset of the behavior over all possible executions of a program (static slices). As the behavior of a program is determined by the semantics of the language, it is reasonable to expect a semantic justification for the practice of program slicing. Program slices have been used in several applications but there is no single notion of a slice that is useful for all applications. This paper identifies and categorizes different notions of a program slice available in the literature as well as several new notions. The various notions are formalized in a denotational framework. Extending the work by Cartwright and Felleisen [2] on the semantics of program dependence, a semantic justification is provided for the process of program slicing using program dependence graphs.