Each code instrumentation point within a file is uniquely identified by its callsite identifier. The callsite identifier is a monotonically increasing integer incrementing from the initial value of 0 for a new module.
As additional files are instrumented and compiled into a module, the start identifier is incremented from the end identifier of the previous file. The predicate retrieves the start and end callsite identifiers for the file.
The predicate is a tool and the callsite identifiers of a file instrumented in a module other than the current calling module context can be retrieved by invoking file_callsites(File, StartId, EndId)@Module.