Accurate Dead Code Detection in Embedded C Code by Arithmetic Constraint Solving

Unreachable code fragments in software, despite not having a negative impact on the functional behavior, can have a bad effect in other areas, such as code optimization or coverage-based code validation and certification. Especially the latter is important in industrial, safety critical environments, where detecting such dead code is a major goal to adjust the coverage of software tests. In the context of embedded systems we focus on C programs which are reactive, control-oriented, and floating-point dominated. Such programs are either automatically generated from Simulink-plus-Stateflow models or hand-written according to coding guidelines. While there are various techniques – e. g. abstract interpretation or Counterexample guided abstraction refinement (CEGAR) – to deal with individual issues of this domain, there is none which can cover all of them. The AVACS transfer project T1 aims at the combination of these techniques in order to provide an accurate and efficient dead code detection. In this paper we present the ideas and goals of the project as well as the current status (including very promising experimental results) and future challenges.