Addressing the EDA Roadblocks for Domain-specific Compilers: An Industry Perspective

Abstract

Computer architects are now widely subscribed to domain-specific architectures as being the only path left for major improvements in performance-cost-energy. As a result, future compilers need to go beyond their traditional role of mapping a design input to a generic hardware platform. Emerging domain-specific compilers must subscribe to a broader view in which compilers provide more control to the end users, enabling customization of hardware components to implement their corresponding tasks. Transitioning into this new design paradigm, where control and customization are key enablers, poses new challenges for domain-specific compiler. Today, generic vendor backend EDA compilers are the only available mechanism to realize a broad range of applications in many domains. The necessity of breadth coverage by commercial tools often leads to implementations that do not take full advantage of the underlying hardware. Domain-specific compilers, on the other hand, can potentially deliver near-spec performance by taking advantage of both application attributes and architecture details. This issue is less pronounced for more generic computing platforms such CPUs due to leveraging open source as an essential component of software development. However, quality EDA software has remained mostly proprietary. Existing open-source attempts do not produce quality results to be useful commercially at scale. Addressing the EDA roadblocks towards quality domain-specific compilers will require stepping milestones from both industry and community. This suggests the need for a framework capable of interfacing between closed source vendor backend tools and open-source domain compilers. RapidWright [1] is an example of such framework that enables a new level of optimization and customization for the application architect to further exploit FPGA silicon capabilities focusing on a specific domain. There are a few factors that will expedite the progress for this approach. For example, RapidStream [2] demonstrates 30% higher performance and more than 5X faster compile time for data flow applications. The key enabler for RapidStream domain compiler is the split-compilation that was made possible for data flow applications with a latency-tolerant front-end and design entry. EDA vendors could enable such bottom-up flows by implementing a foundational infrastructure that allows multiple application modules to be implemented independently. Another useful step would be to decouple certain portions of monolithic EDA tools with separate more permissible licensing to be combined with open-source domain compilers. Another key step that is required for domain-specific compilers to be successful is a process to offer a guarantee to the end customer. Today's vendor tool flow offers full guarantee and support to the end customer at the expense of limiting the customization and control. The new paradigm of domain-specific compilers implies many variations of the tool flow, and it might not be feasible to provide the same level of support and guarantee as existing standard flows. The community needs to explore alternative ways of offering an equivalent level of support and guarantee to the end users in order to make domain-specific compilers widely adopted.