Principles for Verification Tools: Separation Logic

A principled approach to the design of program verification and construction tools is applied to separation logic. The control flow is modelled by power series with convolution as separating conjunction. A generic construction lifts resource monoids to assertion and predicate transformer quantales. The data flow is captured by concrete store/heap models. These are linked to the separation algebra by soundness proofs. Verification conditions and transformation laws are derived by equational reasoning within the predicate transformer quantale. This separation of concerns makes an implementation in the Isabelle/HOL proof assistant simple and highly automatic. The resulting tool is correct by construction; it is explained on the classical linked list reversal example.