Experimental results from dynamic slicing of C programs

Program slicing is a program analysis technique that has been studied in the context of several different applications in the construction, optimization, maintenance, testing, and debugging of programs. 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). However, these algorithms have been studied only in the context of small abstract languages. Program slicing is bound to remain an academic exercise unless one can not only demonstrate the feasibility of building a slicer for nontrivial programs written in a real programming language, but also verify that a type of slice is sufficiently thin, on the average, for the application for which it is chosen. In this article, we present results from using SLICE, a dynamic program slicer for C programs, designed and implemented to experiment with several different kinds of program slices and to study them both qualitatively and quantitatively. Several application programs, ranging in size (i.e., number of lines of code) over two orders of magnitude, were sliced exhaustively to obtain average worst-case metrics for the size of program slices.