A software analysis system for capturing tags generated by tag statements in instrumented source code. The system includes a probe that monitors the address and data bus of the target system. When a tag statement is executed in the target system, a tag is written to a predetermined location in the address space of the target. The tag contains a tag value that is indicative of the location in the source code of the tag statement generating the tag. The source code instrumenter includes a language-dependent parser and a language-independent analyzer that records tagging data in a symbol database. The system performs a variety of analysis functions in essentially real time, including code coverage, function and task execution times, memory allocation, call pairs, and program tracing.