Abstract-Design debugging is becoming an increasingly difficult task in the VLSI design flow with the growing size of modern designs and their error traces. In this work, a novel abstraction and refinement technique for design debugging is presented that addresses two key components of the debugging complexity, the design size and the error trace length. The abstraction technique works by under-approximating the debugging problem by removing modules of the original design and replacing them with simulated values of the erroneous circuit. After each abstract problem is solved, the refinement strategy uses the resulting UNSAT core to direct which modules should be refined. This refinement strategy is extended by allowing refinement of across time-frames in addition to modules. Experimental results show that the proposed algorithm is able to return solutions for all instances compared to only 41% without the technique demonstrating the viability of this approach in tackling realworld debugging problems.

Abstract-Computer-aided design tools are continuously improving their scalability and efficiency to mitigate the high cost associated with designing and fabricating modern VLSI systems. A key step in the design process is the root-cause analysis of detected errors. Debugging may take months to close, introduce high cost and uncertainty ultimately jeopardizing the chip release date. This study makes the case for debug automation in each part of the design flow (RTL to silicon) to bridge the gap. Contemporary research, challenges and future directions motivate for the urgent need in automation to relieve the pain from this highly manual task.

Abstract-With the growing complexity of VLSI designs, functional debugging has become a bottleneck in modern CAD flows. To alleviate this cost, various SAT-based techniques have been developed to automate bug localization in the RTL. In this context, dominance relationships between circuit blocks have been recently shown to reduce the number of SAT solver calls, using the concept of solution implications. This paper first introduces the dual concepts of reverse domination and non-solution implications. A SAT solver is tailored to leverage reverse dominators for the early on-the-fly detection of bug-free components. These are nonsolution areas and their early pruning significantly reduces the the debugging search-space. This process is expedited by branching on error-select variables first. Extensive experiments on tough real-life industrial debugging cases show an average speedup of 1.7x in SAT solving time over the state-of-the-art, a testimony of the practicality and effectiveness of the proposed approach.

Abstract-In today's complex SoC designs, verification and debugging are becoming ever more crucial and increasingly timeconsuming tasks. The prevalence of embedded memories adds to the difficulty of the problem by exponentially increasing the statespace of the design. In this work, a novel memory model for design debugging is presented. It models memory succinctly by avoiding an explicit representation for each memory bit. The method uses the simulation of the erroneous design to guide the debugging process. This results in a parameterizable formal encoding that grows linearly with the erroneous trace length, significantly reducing the memory requirements of the debugging problem. In addition, the proposed model is extended to handle an arbitrary initial memory configuration, as well as non-cycle accurate output traces where only a final expected memory state is available for comparison. Experiments on industrial designs show a 96% average reduction in memory usage along with a noticeable performance improvement compared to previous work.