Evaluation of Automatic Flow Analysis for WCET Calculation on Industrial Real-Time System Code

A static Worst-Case Execution Time (WCET) ana-lysis derives upper bounds for the execution times of programs. Such analysis requires information about the possible program flows. The current practice is to pro-vide this information manually, which can be laborious and error-prone. An alternative is to derive this infor-mation through an automated flow analysis. In this article, we present a case study where an au-tomatic flow analysis method was tested on industrial real-time system code. The same code was the subject of an earlier WCET case study, where it was analysed us-ing manual annotations for the flow information. The purpose of the current study was to see to which extent the same flow information could be found automati-cally. The results show that for the most part this is indeed possible, and we could derive comparable WCET estimates using the automatically generated flow infor-mation. In addition, valuable insights were gained on what is needed to make flow analysis methods work on real production code.