An alternative approach to developing reusable components from scratch is to recover them from existing systems. In this paper, we apply program slicing, a program decomposition method, to the problem of extracting reusable functions from illstructured programs. As with conventional slicing first described by Weiser, a slice is obtained by iteratively solving data flow equations based on a prog...

Program slicing identifies parts of a program that potentially affect a chosen computation. It has many applications in software engineering, including maintenance, evolution and re-engineering of legacy systems. However, these systems typically contain programs with unstructured control-flow, produced using goto statements; thus, effective slicing of unstructured programs remains an important ...

Program slices have long been used as an aid to program understanding, especially in maintenance activities. Most slicing methods involve data and control flow analysis to determine what statements might affect a set of variables. Here, we develop a more precise slicing concept, called p-slices, defined using Dijkstra’s weakest precondition (wp), to determine which statements will affect a spec...

Program slicing is an analysis that answers questions such as \Which statements might aaect the computation of variable v at statement s?" or \Which statements depend on the value of v computed in statement s?". The answers computed by program slicing are generally a set of statements. We introduce the idea of iteration spacing slicing: we reene program slicing to ask questions such as \Which i...

This paper studies program slicing in the presence of input statements. If unnecessary input statements are sliced away, the remaining input statements are assumed to read the same data as within the entire program. For specifying the relation of one program being a slice of another under this assumption, one needs a formalism for treating “stages of computation”. This paper presents an approac...