An Empirical Study of Amorphous Slicing as a Program Comprehension Support Tool

Amorphous program slicing relaxes the syntactic constraint of traditional slicing and can therefore produce considerably smaller slices. This simplification power can be used to answer questions a software engineer might have about a program by first augmenting the program to make the question explicit and then slicing out an answer. One benefit of this technique is that the answer is in the form of a program and thus, in a language that the software engineer understands well. To test the usefulness of amorphous slicing in answering such questions, the question of array access safety is considered. A safety slice, an amorphous slice of an augmented program, is used to guide a software engineer to potential array bounds violations. An experiment was conducted to determine whether the safety slice was an effective aid to an engineer. Sev enty six subjects participated in the controlled experiment. For experiments involving groups of novice programmers, the null hypothesis could not be rejected, and so it was not possible to conclude that amorphous slicing provided assisted such groups. However, for more experienced groups, the experimental subjects who were able to consult † Computer Science Department, Loyola College in Maryland, 4501 North Charles Street, Baltimore, MD 21210 {binkley,lraszews,csmith}@cs.loyola.edu. Supported by National Science Foundation grant CCR-9803665. ‡ Department of Mathematical and Computing Sciences, Goldsmiths College, University of London, New Cross, London SE14 6NW [email protected] Supported by Engineering and Physical Sciences Research Council grants GR/M58719 and GR/M78083. Copyright © 1999 by David Binkley. All rights reserved. amorphous slices significantly outperformed the control group. The study lends empirical support to the assertion that amorphous slicing is an assistant to program comprehension. Ke ywords: slicing, empirical validation, amorphous slicing, arrays