Compiler Support for Real-Time Programs

We present a compiler-based approach to automatically assist in constructing real-time systems. In this approach, source programs are written in TCEL (or Time Constrained Event Language) which possesses high-level timing constructs, and whose semantics characterizes time-constrained relationships between observable events. A TCEL program infers only those timing constraints necessary to achieve real-time correctness, without over-constraining the system. We exploit this looser semantics to help transform programs to automatically achieve schedulability. In this article we present two such transformations. The first is trace-scheduling, which we use to achieve consistency between a program's worst-case execution time and its real-time requirements. The second is program-slicing, which we use to automatically tune application programs driven by rate-monotonic scheduling. (Also cross-referenced as UMIACS-TR-94-15