Generic program monitoring by trace analysis

Program execution monitoring consists of checking whole executions for given properties in order to collect global run-time information. Monitoring is very useful to maintain programs. However, application developers face the following dilemma: either they use existing tools which never exactly t their needs, or they invest a lot of e ort to implement monitoring code. In this report we argue that, when an event-oriented tracer exists, the compiler developers can enable the application developers to easily code their own, relevant, monitors. We propose a high-level operator, called foldt, which operates on execution traces. One of the key advantages of our approach is that it allows a clean separation of concerns; the de nition of monitors is totally distinct from both the user source code and the language compiler. We give a number of applications of the foldt operator to compute monitors for Mercury program executions: execution pro les, graphical abstract views, and two test coverage measurements. Each example is implemented by a few simple lines of Mercury. Key-words: dynamic program analysis, monitoring, trace analysis, test coverage, logic and functional programming, Mercury programming language