Tracing Execution of CLP(FD) Programs : A Trace Model and an Experimental Validation Environment

Developing and maintaining Constraint Logic Programs (CLP) requires performanc- e debugging tools based on visualization and explanation. However, existing tools are built in an ad hoc way and porting them from one platform to another is very difficult and experimentation of new tools remains limited. It has been shown in previous work that, from a fine-grained execution trace, a number of interesting views about logic program executions could be generated by trace analysis. In this report, we propose a generic trace model for constraint resolution by narrowing and a methodology to study and improve it. The trace model is the first one proposed for and does not pretend to be the ultimate one. The methodology is based on the following steps: definition of a formal model of trace, extraction of relevant informations by a trace analyzer, utilization of the extracted informations in several debugging tools. We present the trace model and an implementation which includes a tracer, based on a meta-interpreter written in ISO-Prolog, and an opium-like analyzer. The efficiency of the tracer is tested and some elementary debugging tools based on trace analysis are experimented. This work sets the basis for generic analysis of behavior of programs. is a short version of this report