Graph-Based ECO and Patch Generation for High-Level Synthesis

TL;DR

This paper presents a graph-based method for efficiently generating and applying patches to high-level synthesis designs, improving late-stage modifications while maintaining correctness.

Contribution

A novel graph-based ECO approach for Google XLS that detects structural differences and applies patches to support design changes effectively.

Findings

High structural reuse ratios achieved across designs

Effective schedule preservation demonstrated

Full functional correctness maintained after patch application

Abstract

High-level synthesis (HLS) tools offer limited support for Engineering Change Orders (ECOs), making late-stage design modifications challenging and costly. This paper introduces a graph-based ECO methodology tailored for Google XLS. A Graph Edit Distance (GED) algorithm is used to detect structural differences between original and revised intermediate representations (IRs), which are then transformed into patch operations. A patch application mechanism is developed to enforce XLS IR constraints while preserving semantic correctness, together with a schedule constraining scheme that maintains the original pipeline registers. Experiments across several XLS designs demonstrate high structural reuse ratios, effective schedule preservation, and full functional correctness, highlighting the practicality of the approach for production HLS flows.