Property-directed reachability as abstract interpretation in the monotone theory

Yotam M.Y. Feldman, Mooly Sagiv, Sharon Shoham, James R. Wilcox

Research output: Contribution to journalArticlepeer-review

Abstract

Inferring inductive invariants is one of the main challenges of formal verification the theory of abstract interpretation provides a rich framework to devise invariant inference algorithms. One of the latest breakthroughs in invariant inference is property-directed reachability (PDR), but the research community views PDR and abstract interpretation as mostly unrelated techniques. This paper shows that, surprisingly, propositional PDR can be formulated as an abstract interpretation algorithm in a logical domain. More precisely, we define a version of PDR, called-PDR, in which all generalizations of counterexamples are used to strengthen a frame. In this way, there is no need to refine frames after their creation, because all the possible supporting facts are included in advance. We analyze this algorithm using notions from Bshouty's monotone theory, originally developed in the context of exact learning. We show that there is an inherent overapproximation between the algorithm's frames that is related to the monotone theory. We then define a new abstract domain in which the best abstract transformer performs this overapproximation, and show that it captures the invariant inference process, i.e.,-PDR corresponds to Kleene iterations with the best transformer in this abstract domain. We provide some sufficient conditions for when this process converges in a small number of iterations, with sometimes an exponential gap from the number of iterations required for naive exact forward reachability these results provide a firm theoretical foundation for the benefits of how PDR tackles forward reachability.

Original languageEnglish
Article number3498676
JournalProceedings of the ACM on Programming Languages
Volume6
Issue numberPOPL
DOIs
StatePublished - Jan 2022

Keywords

  • abstract interpretation
  • invariant inference
  • monotone theory
  • property-directed reachability
  • reachability diameter

Fingerprint

Dive into the research topics of 'Property-directed reachability as abstract interpretation in the monotone theory'. Together they form a unique fingerprint.

Cite this