light weight circuit tracing tool

this can a free open source tool, based on the methodology of
"text tracing". the interface can be line based.

ATPG based on meaningful circut analysis

Circuit design info can be used to facilitate test generation. Such info is not limited to just the counts of DFF, or clock domain info. More meaningful info related to the functionality, certain design style, like connecting a net to many components, adding a lot of buffers. Such info can be used to tune ATPG strategy.