Merging Techniques for Faster Derivation of WCET Flow Information using Abstract Execution

Abstract

Static Worst-Case Execution Time (WCET) analysis derives upper bounds for the execution times of programs. Such bounds are crucial when designing and verifying real-time systems. A key component in static WCET analysis is to derive flow information, such as loop bounds and infeasible paths. We have previously introduced abstract execution (AE), a method capable of deriving very precise flow information. This paper present different merging techniques that can be used by AE for trading analysis time for flow information precision. It also presents a new technique, ordered merging, which may radically shorten AE analysis times, especially when analyzing large programs with many possible input variable values