  High-Level Synthesis (HLS) frameworks allow to easily specify a large number
of variants of the same hardware design by only acting on optimization
directives. Nonetheless, the hardware synthesis of implementations for all
possible combinations of directive values is impractical even for simple
designs. Addressing this shortcoming, many HLS Design Space Exploration (DSE)
strategies have been proposed to devise directive settings leading to
high-quality implementations while limiting the number of synthesis runs. All
these works require considerable efforts to validate the proposed strategies
and/or to build the knowledge base employed to tune abstract models, as both
tasks mandate the syntheses of large collections of implementations. Currently,
such data gathering is performed ad-hoc, a) leading to a lack of
standardization, hampering comparisons between DSE alternatives, and b) posing
a very high burden to researchers willing to develop novel DSE strategies.
Against this backdrop, we here introduce DB4HLS, a database of exhaustive HLS
explorations comprising more than 100000 design points collected over 4 years
of synthesis time. The open structure of DB4HLS allows the incremental
integration of new DSEs, which can be easily defined with a dedicated
domain-specific language. We think that of our database, available at
https://www.db4hls.inf.usi.ch/, will be a valuable tool for the research
community investigating automated strategies for the optimization of HLS-based
hardware designs.
