Compilation and Worst-Case Execution-Time Analysis

Why Compiler-Support for WCET Analysis? Compiler “knows ” both code representations • Source code (the user representation) • Object code (the instructions determining timing) Compiler “knows ” the transformations it applies • optimizations could target the worst-case path ➭ Compiler can generate information that is relevant for WCET analysis ➭ Compiler can generate time-predictable code (cache locking, pre-fetching for scratch-pad, single-path code, avoidance of timing anomalies, etc.) 2 A Related Problem – Source-level debugging Source-level debugging faces similar challenges as timing analysis of optimized code: • Mapping between source code and object code becomes blurred due to code transformations • In debugging, code locations and store (memory, variables, etc.) content have to be mapped • In timing analysis, flow information has to be mapped to object code and timing results need to be mapped to the source code. 3 A Related Problem – Source-level debugging int test (int a) int b = a; int c = b + 4; return c;