Traditional, syntax-preserving program slicing simpli es a program by deleting components (e.g., statements and predicates) that do not aect a computation of interest. Amorphous slicing removes the limitation to component deletion as the only means of simpli cation, while retaining the semantic property that a slice preserves the selected behaviour of interest from the original program. This leads to slices which are often considerably smaller than their syntax-preserving counterparts.

While mutation testing has proved to be an effective way of finding software faults, currently it is only applied to relatively small programs. One of the main reasons for this is the human analysis required in detecting equivalent mutants. Here program slicing is used to simplify this problem. Program slicing is also used to reduce the number of equivalent mutants produced.

Program slicing is a viable method to restrict the focus of a task to specific sub-components of a program. Examples of applications include debugging, testing, program comprehension, restructuring, downsizing, and parallelization. This paper discusses different statement deletion based slicing methods, together with algorithms and applications to software engineering.

Program Slicing is the process of deleting statements in a program that do not affect a given set of variables at a chosen point in the program. In this paper the first parallel slicing algorithm for static program slicing is introduced. It is shown how the control flow graph of the program to be sliced is converted into a network of concurrent processes, thereby producing a parallel version of Weiser's original static slicing algorithm. The parallel slicing algorithm is formally defined as the least solution (containing the slicing criterion) of a set of recursion equations, derived from the program's control flow graph and is proved correct with respect to Weiser's algorithm. The parallel slicing algorithm has a number of other interesting and potentially useful properties. For example, in addition to constructing a slice, it produces a set of equivalent slicing criteria for the slice it constructs.

This paper shows how analysis of programs in terms of pre- and post- conditions can be improved using a generalisation of conditioned program slicing called pre/post conditioned slicing. Such conditions play an important role in program comprehension, reuse, verification and reengineering. Fully automated analysis is impossible because of the inherent undecidability of pre- and post- conditions. The method presented here reformulates the problem to circumvent this. The reformulation is constructed so that programs which respect the pre- and post-conditions applied to them have empty slices. For those which do not respect the conditions, the slice contains statements which could potentially break the conditions. This separates the automatable part of the analysis from the human analysis.

This paper introduces a modification of Agrawal's algorithm for slicing unstructured programs, which overcomes these difficulties. The new algorithm produces thinner slices than any previously published algorithm while respecting both the semantic and syntactic constraints of slicing. c fl1998 by John Wiley & Sons, Ltd.

This paper describes a program slicing tool, unravel, that can assist in the evaluation of high integrity software by using program slices to extract a single computation from a program for examination and test. The tool, available through the National Institute of Standards and Technology, can currently be used to evaluate software written in ANSI C and is designed such that other languages can be added. I. INTRODUCTION High integrity software systems are often used in environments where a lack of response can cause an accident or result in severe financial loss due to an operational failure. Detecting a fault in the code is difficult and costly. This paper describes a program slicing tool, unravel, that can assist in the evaluation of high integrity software by using program slices to extract a single computation for examination and test. The tool, available through the National Institute of Standards and Technology[6], can currently be used to evaluate software written in ANSI C a...

This paper presents a system for amorphous program slicing which combines slicing and transformation to achieve thinner slices than are possible using conventional syntax-preserving slicing. The approach involves the validation of the transformation and slicing steps using the Coq proof assistant, thereby guaranteeing the correctness of the amorphous slices produced. The combined application of slicing and transformation is illustrated with a simple case study.

Program conditioning consists of identifying and removing a set of statements which cannot be executed when a condition of interest holds at some point in a program. It has been applied to problems in maintenance, testing, re--use and re-engineering. Program conditioning relies upon both symbolic execution and reasoning about symbolic predicates. Automation of the process therefore requires some form of automated theorem proving. However, the use of a full-power `heavyweight' theorem prover would impose unrealistic performance constraints. This paper

Program slicing can be used as a support for program comprehension, because it allows a large program to be divided up into smaller slices, each of which can be understood in isolation from the rest. As such, slicing facilitates the familiar approach of `divide and conquer'.