Please use this identifier to cite or link to this item: http://bura.brunel.ac.uk/handle/2438/7566
Title: Complexity of data dependence problems for program schemas with concurrency
Authors: Danicic, S
Hierons, RM
Laurence, MR
Keywords: Program analysis;Data dependence;Program schemas;Free schemas;Herbrand domain
Issue Date: 2012
Publisher: Association for Computing Machinery (ACM)
Citation: ACM Transactions on Computational Logic, 13(2): Artn 15, Apr 2012
Abstract: The problem of deciding whether one point in a program is data dependent upon another is fundamental to program analysis and has been widely studied. In this article we consider this problem at the abstraction level of program schemas in which computations occur in the Herbrand domain of terms and predicate symbols, which represent arbitrary predicate functions, are allowed. Given a vertex l in the flowchart of a schema S having only equality (variable copying) assignments, and variables v, w, we show that it is PSPACE-hard to decide whether there exists an execution of a program defined by S in which v holds the initial value of w at at least one occurrence of l on the path of execution, with membership in PSPACE holding provided there is a constant upper bound on the arity of any predicate in S. We also consider the ‘dual’ problem in which v is required to hold the initial value of w at every occurrence of l, for which the analogous results hold. Additionally, the former problem for programs with nondeterministic branching (in effect, free schemas) in which assignments with functions are allowed is proved to be polynomial-time decidable provided a constant upper bound is placed upon the number of occurrences of the concurrency operator in the schemas being considered. This result is promising since many concurrent systems have a relatively small number of threads (concurrent processes), especially when compared with the number of statements they have.
Description: This is the pre-print version of the Article. The official published version can be accessed from the links below. Copyright @ 2012 ACM
URI: http://dl.acm.org/citation.cfm?doid=2159531.2159537
http://bura.brunel.ac.uk/handle/2438/7566
DOI: http://dx.doi.org/10.1145/2159531.2159537
ISSN: 1529-3785
Appears in Collections:Publications
Computer Science
Dept of Computer Science Research Papers

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