The notion of control dependence underlies many program analysis and transformation techniques. Despite being widely used, existing definitions and approaches to calculating control dependence are difficult to apply directly to modern program structures because these make substantial use of exception processing and increasingly support reactive systems designed to run indefinitely. This article revisits foundational issues surrounding control dependence, and develops definitions and algorithms for computing several variations of control dependence that can be directly applied to modern program structures. To provide a foundation for slicing reactive systems, the article proposes a notion of slicing correctness based on weak bisimulation, and proves that some of these new definitions of control dependence generate slices that conform to this notion of correctness. This new framework of control dependence definitions, with corresponding correctness results, is even able to support programs with irreducible control flow graphs. Finally, a variety of properties show that the new definitions conservatively extend classic definitions. These new definitions and algorithms form the basis of the Indus Java slicer, a publicly available program slicer that has been implemented for full Java. Permission to make digital or hard copies part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or direct commercial advantage and that copies show this notice on the first page or initial screen of a display along with the full citation. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, to redistribute to lists, or to use any component of this work in other works requires prior specific permission and/or a fee. Permissions may be requested from Publications Dept., ACM, Inc., 2 Penn Plaza, Suite 701, New York, NY 10121-0701 USA, fax +
