AutoSLIDE: Automatic Source-Level Instrumentation and Debugging for HLS

Abstract

Improved quality of results from high level synthesis (HLS) tools have led to their increased adoption in hardware design. However, functional verification of HLS-produced designs remains a major challenge. Once a bug is exposed, designers must backtrace thousands of signals and simulation cycles to determine the underlying cause. The challenge is further exacerbated with HLS-produced non-human-readable RTL. In this paper, we present AutoSLIDE, an automated cross-layer verification framework that instruments critical operations, detects discrepancies between software and hardware execution, and traces the suspect datapath tree to identify bug source for the detected discrepancy. AutoSLIDE also maintains mappings between RTL datapath operations, LLVM-IR operations, and C/C++ source code to precisely pinpoint the root-cause of bugs to the exact line/operation in source code, substantially reducing user effort to localize bugs. We demonstrate the effectiveness by detecting and localizing bugs from former versions of the CHStone benchmark suite. Furthermore, we demonstrate the efficiency of AutoSLIDE, with low overhead in HLS time (27%), software trace gathering (10%), and significantly reduced trace size and simulation time compared to exhaustive instrumentation.