Tracers provide users with useful information about program executions. In
this article, we propose a ``tracer driver''. From a single tracer, it provides
a powerful front-end enabling multiple dynamic analysis tools to be easily
implemented, while limiting the overhead of the trace generation. The relevant
execution events are specified by flexible event patterns and a large variety
of trace data can be given either systematically or ``on demand''. The proposed
tracer driver has been designed in the context of constraint logic programming;
experiments have been made within GNU-Prolog. Execution views provided by
existing tools have been easily emulated with a negligible overhead.
Experimental measures show that the flexibility and power of the described
architecture lead to good performance. The tracer driver overhead is inversely
proportional to the average time between two traced events. Whereas the
principles of the tracer driver are independent of the traced programming
language, it is best suited for high-level languages, such as constraint logic
programming, where each traced execution event encompasses numerous low-level
execution steps. Furthermore, constraint logic programming is especially hard
to debug. The current environments do not provide all the useful dynamic
analysis tools. They can significantly benefit from our tracer driver which
enables dynamic analyses to be integrated at a very low cost.Comment: To appear in Theory and Practice of Logic Programming (TPLP),
Cambridge University Press. 30 pages