Deriving bisimulation relations from path based equivalence checkers

• Published in: Formal aspects of computing Vol. 29; no. 2; pp. 365 - 379
• Main Authors: Banerjee, Kunal, Sarkar, Dipankar, Mandal, Chittaranjan
• Format: Journal Article
• Language: English
• Published: London Springer London 01.03.2017; Association for Computing Machinery
• Subjects: Checkers; Computation; Computer Science; Constrictions; Construction; Equivalence; Math Applications in Computer Science; Methodology; Original Article; Propagation; Theory of Computation; Translations; Bisimulation relation; Path based equivalence checker; Value propagation; Translation validation
• ISSN: 0934-5043; 1433-299X
• DOI: 10.1007/s00165-016-0406-y

Translation validation is an undecidable problem. Bisimulation relation based approaches, nevertheless, have been widely successful in translation validation of programs albeit with some drawbacks. These drawbacks include non-termination of the verification methodology and significant restrictions on the structures of programs to be checked for equivalence. We have developed a path based equivalence checker which propagates mismatched values over consecutive paths to alleviate these drawbacks. In this work, we show how a bisimulation relation between a program and its translated version can be constructed from the outputs of such a value propagation based equivalence checker. Moreover, none of the earlier methods that establish equivalence through construction of bisimulation relations has been shown to tackle code motions across loops; the present work demonstrates, for the first time, the existence of a bisimulation relation under such a situation.