Worst-Case Execution Time (WCET) analysis is an important research area in various application areas, like real-time and embedded programming as well as a wide range of other high performance applications. However, WCET analysis is a complex and difficult area, because the processor's cache operations, interrupt routines and the operating system impact the execution time. Also, it is very difficult to replicate a specified scenario. Measuring the worst-case execution time as an absolute quantity therefore is still an unsolved problem for the most popular programming languages. In the same time, WCET calculation is also important on the source code level.