Clara: A Framework for Partially Evaluating Finite-State Runtime Monitors Ahead of Time

Researchers have developed a number of runtime verification tools that generate runtime monitors in the form of AspectJ aspects. In this work, we present CLARA, a novel framework to statically optimize such monitoring aspects with respect to a given program under test. CLARA uses a sequence of increasingly precise static analyses to automatically convert a monitoring aspect into a residual runtime monitor. The residual monitor only watches events triggered by program locations that the analyses failed to prove safe at compile time. In two-thirds of the cases in our experiments, the static analysis succeeds on all locations, proving that the program fulfills the stated properties, and completely obviating the need for runtime monitoring. In the remaining cases, the residual runtime monitor is usually much more efficient than a full monitor, yet still captures all property violations at runtime.