Grammar Instrumentation

This is the most important and crucial phase of the whole test coverage analysis process. It accepts the grammar specifications for the source language and generates the instrumented grammar specifications along with some supporting modules that are used for instrumenting the source programs. The grammar specifications are in the form of yacc specifications for the language. The instrumentation of grammar involves three steps that are usually carried out manually.

Identifying places for inserting probe actions: This activity depends on the coverage measures that the Test Coverage Analyzer incorporates. For example, for branch coverage the probe actions should be inserted in the production rules of those constructs in the language that transfer the control, like if statement, switch statement etc. In order to insert the probe actions, the yacc production rules for these constructs must be identified along with the position in the rules where the probe actions should be inserted.

Inserting probes actions: This process deals with inserting probe actions in the selected production rules. The probe actions that are to be inserted depend on the coverage measures incorporated by the Test Coverage Analyzer. These probe actions are responsible for instrumenting the source programs and for generating the data structures required for program instrumentation.

Generating supporting modules: This process involves the writing of supporting modules for source program instrumentation. The supporting modules include routines that: read the source program, manipulate the data structures used for instrumentation, and generate the supporting routines for probes in the instrumented programs.

At the end of the Grammar Instrumentation phase, the instrumented grammar specifications and supporting routines are obtained. These are compiled to generate the ``Program Instrumenter", which is used to instrument the source programs.