Imprecision in WCET estimates due to library calls and how to reduce it (WIP paper)

One of the main difficulties in estimating the Worst Case Execution Time (WCET) at the binary level is that machine instructions do not allow inferring call contexts as precisely as source code, since compiler optimizations obfuscate control flow and type information. On the other hand, WCET estimation at source code level can be precise in tracking call contexts, but it is pessimistic for functions that are not available as source code. In this paper we propose approaches to join binary-level and source-level analyses, to get the best out of both. We present the arising problems in detail, evaluate the approaches qualitatively, and highlight their trade-offs.