Boogie is a program verification condition generator for an imperative core language. It has front-ends for the programming languages C# and C enriched by annotations in first-order logic. Its verification conditions — constructed via a wp calculus from these annotations — are usually transferred to automated theorem provers such as Simplify or Z3. In this paper, however, we present a proof-environment, HOL-Boogie, that combines Boogie with the interactive theorem prover Isabelle/HOL. In particular, we present specific techniques combining automated and interactive proof methods for code-verification.

We will exploit our proof-environment in two ways: First, we present scenarios to “debug” annotations (in particular: invariants) by interactive proofs. Second, we use our environment also to verify “background theories”, i.e. theories for data-types used in annotations as well as memory and machine models underlying the verification method for C.