Pecker: Bug Localization Framework for Sequential Designs via Causal Chain Reconstruction

TL;DR

Pecker is a bug localization framework that reconstructs causal chains in sequential hardware designs, significantly improving bug localization accuracy over existing methods.

Contribution

It introduces temporal backtracking and trace pruning techniques to address challenges in bug localization for sequential hardware designs.

Findings

Localizes 51%/80%/85% bugs within Top-1/3/5 ranks

Outperforms state-of-the-art techniques on sequential designs

Maintains robustness across different circuit complexities

Abstract

Debugging represents a time-consuming and labor-intensive task in hardware design, with bug localization constituting a substantial portion of this process. While spectrum-based bug localization techniques have achieved remarkable success in software domains and shown promise for hardware description languages, their effectiveness severely degrades in sequential designs. Unlike software programs, hardware designs exhibit intrinsic temporal characteristics that create fundamental challenges: timing misalignment between bug activation and observation, and progressive error propagation through state elements that obscures the root cause. To address these limitations, we propose Pecker, a novel bug localization framework that reconstructs the broken causal chain in sequential designs. Our approach introduces two key innovations: temporal backtracking using Estimated Minimal Propagation Cycles to identify potential activation cycles, strategic trace pruning to eliminate state pollution effects. We evaluate Pecker on comprehensive benchmarks comprising both combinational and sequential circuits. Experimental results demonstrate that Pecker effectively localizes 51%/80%/85% bugs within Top-1/3/5 ranks respectively, significantly outperforming state-of-the-art techniques. Notably, Pecker maintains robust performance across circuit complexities while existing methods exhibit severe degradation on sequential designs.