Automatic Verification of Time Behavior of Programs

Automatic verification of software could save companies from huge losses due to errors in their programs. Existing techniques to prevent and detect errors are mainly based on imprecise heuristics which can report false positives. Formal verification techniques are an alternative to the heuristic approaches. They are more precise and can report errors with higher rigor. However, they cannot be directly applied because current programming languages have no defined semantics that specifies how the source code is interpreted in the execution of programs. Moreover, no existing work tries to develop a semantics for the time domain. The target of this thesis is to provide a verification framework based on a defined time semantics that can help developers to automatically detect time related errors in the behavior of programs. We define a time semantics that allows us to ascribe a meaning to source code statements that alter and use time. Based on the time semantics, we develop an approach to (i) automatically assert time properties and (ii) reverse engineer timed automata, a formal model of the time behavior that is amenable for verification. We plan to evaluate our approaches with quantitative and qualitative studies. The quantitative studies will measure the performance of our approaches in open source projects and the qualitative studies will collect the developers' feedback about the applicability and usefulness of our proposed techniques.