Explaining Counterexamples with Giant-Step Assertion Checking - Inria - Institut national de recherche en sciences et technologies du numérique Access content directly
Conference Papers Year : 2021

Explaining Counterexamples with Giant-Step Assertion Checking

Abstract

Identifying the cause of a proof failure during deductive verification of programs is hard: it may be due to an incorrectness in the program, an incompleteness in the program annotations, or an incompleteness of the prover. The changes needed to resolve a proof failure depend on its category, but the prover cannot provide any help on the categorisation. When using an SMT solver to discharge a proof obligation, that solver can propose a model from a failed attempt, from which a possible counterexample can be derived. But the counterexample may be invalid, in which case it may add more confusion than help. To check the validity of a counterexample and to categorise the proof failure, we propose the comparison between the run-time assertion-checking (RAC) executions under two different semantics, using the counterexample as an oracle. The first RAC execution follows the normal program semantics, and a violation of a program annotation indicates an incorrectness in the program. The second RAC execution follows a novel "giant-step" semantics that does not execute loops nor function calls but instead retrieves return values and values of modified variables from the oracle. A violation of the program annotations only observed under giant-step execution characterises an incompleteness of the program annotations. We implemented this approach in the Why3 platform for deductive program verification and evaluated it using examples from prior literature.
Fichier principal
Vignette du fichier
fide.pdf (159.15 Ko) Télécharger le fichier
Origin : Files produced by the author(s)

Dates and versions

hal-03217393 , version 1 (04-05-2021)

Identifiers

Cite

Benedikt Becker, Cláudio Belo Lourenço, Claude Marché. Explaining Counterexamples with Giant-Step Assertion Checking. F-IDE 2021 - 6th Workshop on Formal Integrated Development Environments, May 2021, Virtual, United States. ⟨10.4204/EPTCS.338.10⟩. ⟨hal-03217393⟩
124 View
133 Download

Altmetric

Share

Gmail Facebook X LinkedIn More