This paper presents LLBMC, a tool for finding bugs and runtime errors in sequential C/C++ programs. LLBMC employs bounded model checking using an SMT-solver for the theory of bitvectors and arrays and thus achieves precision down to the level of single bits. The two main features of LLBMC that distinguish it from other bounded model checking tools for C/C++ are (i) its bit-precise memory model, which makes it possible to support arbitrary type conversions via stores and loads; and (ii) that it operates on a compiler intermediate representation and not directly on the source code.

Synchronization between component requirements and implementation centric tests remains a challenge that is usually addressed by requirements reviews with testers and traceability policies. The claim of this work is that linking requirements, their scenario-based formalizations, and software verification provides a promising extension to this approach. Formalized scenarios, for example in the form of low-level assume/assert statements in C, are easier to trace to requirements than traditional test sets. For a verification engineer, they offer an opportunity to better participate in requirements changes. Changes in requirements can be more easily propagated because adapting formalized scenarios is often easier than deriving and updating a large set of test cases. The proposed idea is evaluated in a case study encompassing over 50 functional requirements of an automotive software developed at Robert Bosch GmbH. Results indicate that requirement formalization together with formal verification leads to the discovery of implementation problems missed in a traditional testing process.