Automated WCET analysis based on program modes

Program mode is a regular trajectory of the execution of a program that is determined by the values of its input variables. By exploiting program modes we may make Worst Case Execution Time (WCET) analysis more precise. This paper presents a novel method to automatically find program modes and calculate the WCET of programs. It consists of two phases. In phase one, we firstly automatically find the modes of a program by mode-relevant program slicing; then we compute the precondition for each mode using a path-wise test data generation method; after that, we can either conclude that it is an infeasible path, or get its precondition. In phase two, we calculate the WCET estimate of each given mode for modern RISC processors with caches and pipelines. The experiments are demonstrated to show the effectiveness of the method.