Technique for identifying RTL and gate-level correspondences

In this paper, we consider the mapping problem of identifying correspondences between a signal in a high-level specification and a net in a lower-level implementation for a given design. Conventional techniques use shared names to associate a signal with a net whenever possible. However, given that a synthesis flow may not preserve names, solutions to the above problem eventually take recourse to expensive alternatives such as formal verification. This work provides a robust framework for identifying RTL signal to gate-level net correspondences for a given design. Our technique exploits the observation that circuit diagnosis provides a convenient means for locating faults in a gate-level network. Since our problem requires locating gate-level nets corresponding to RTL signals, we formulate the mapping problem as a query whose solution is provided by a circuit diagnosis engine. Our experimental work with industrial designs for many mapping cases shows that our solution to the mapping problem is (i) fast, and (ii) precise in identifying the gate-level equivalents (the number of nets returned by our mapping engine for a query is typically 1 or 2 even for designs with tens of thousands of VHDL lines).