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Feedback-Guided Circuit Structure Mutation for Testing Hardware Model Checkers

We introduce Circuit Structure Mutation, a simple but effective mutation-based testing approach, for testing hardware model checkers. The key idea is to mutate the existing And-Inverter Graph (AIG) circuit by manipulating the relations among the components in the graph while preserving the validity of the mutant. Based on Circuit Structure Mutation, we implemented a feedback-guided testing tool named Hammer. In our evaluation, Hammer shows its effectiveness on finding bugs, increasing test coverage, and finding performance optimization chances, which can help the hardware model checker developers improve the reliability and the performance of their tools.