Ligia Nicoleta Nistor

The presence of aliasing makes modular verification of object-oriented code difficult. If multiple clients depend on the properties of an object, one client may break a property that others depend on.

In this thesis we present a modular verification approach based on the novel abstraction of object propositions, which combine predicates and information about object aliasing. In our methodology, even if shared data is modified, we know that an object invariant specified by a client holds. Our permission system allows verification using a mixture of linear and nonlinear reasoning. This allows it to provide more modularity in some cases than competing separation logic approaches, because it can more effectively hide the exact aliasing relationships within a module. We have implemented the methodology into our tool Oprop. We have used Oprop to automatically verify a number of examples, thus showing the applicability of this research.