Reducing Instrumentation Intrusion for Coverage and Reconnaissance

摘要

Modern software is more likely to be multi-threaded and/or multi-processed which increases the concurrency and possible race conditions in the implementations. Tools designed for code coverage and tracing on a monolithic system commonly alter the execution of the underlying software thereby causing timing errors when used in concurrent environments. This paper presents a method of tracing the execution of software that can significantly reduce the modification of behavior. Execution tracing is done through the setting of a single bit from a defined bit string as each instrumentation point is reached in execution. A dedicated run-time thread stores the bit string and clears it for the next execution interval. By adjusting the length of the collection interval, the bit string can collect data from periods ranging from a single instruction's execution to the entire program's execution. Example uses of the technique in code coverage and software reconnaissance are provided.