Partial Flow Analysis with oRange

In order to ensure that timing constrains are met for a Real-Time Systems, a bound of the Worst-Case Execution Time (WCET) of each part of the system must be known. Current WCET computation methods are applied on whole programs which means that all the source code should be available. However, more and more, embedded software uses COTS (Components ...), often afforded only as a binary code. Partialisation is a way to solve this problem.

In general, static WCET analysis uses upper bound on the number of loop iterations. oRange is our method and its associated tool which provide mainly loop bound values or equations and other flow facts information. In this article, we present how we can do partial flow analysis with oRange in order to obtain component partial results. These partial results can be used, in order to compute the flow analysis in the context of a full application. Additionally, we show that the partial analysis enables us to reduce the analysis time while introducing very little pessimism.