Directed Test Generation for Hardware Validation: A Survey

Abstract

The complexity of hardware designs has increased over the years due to the rapid advancement of technology coupled with the need to support diverse and complex features. The increasing design complexity directly translates to difficulty in verifying functional behaviors as well as non-functional requirements. Simulation is the most widely used form of validation using both random and constrained-random test patterns. The random nature of test sequences can cover a vast majority of scenarios, however, it can introduce unacceptable overhead to cover all possible functional and non-functional scenarios. Directed tests are promising to cover the remaining corner cases and hard-to-detect scenarios. Manual development of directed tests can be time-consuming and error-prone. A promising avenue is to perform automated generation of directed tests. In this article, we provide a comprehensive survey of directed test generation techniques for hardware validation. Specifically, we first introduce the complexity of hardware verification to highlight the need for directed test generation. Next, we describe directed test generation using various automated techniques, including formal methods, concolic testing, and machine learning. Finally, we discuss how to effectively utilize the generated test patterns in different validation scenarios, including pre-silicon functional validation, post-silicon debug, as well as validation of non-functional requirements.