Python Wraps Yosys for Rapid Open-Source EDA Application Development

Abstract

Yosys is an open-source synthesis and verification tool which natively supports Verilog-2005 and offers a variety of passes to allow a user to adapt the design and verification flow. A user can extend the functionality of Yosys with a plugin interface in C++. C++ is a powerful language, and it is easy to lose track in fixing low-level issues like memory allocation, instead of focusing on the original problem. This can significantly increase the length of the compile/debug cycle. Python, on the other hand, is a dynamically-typed, garbage-collected language which takes away low-level management from the user, who can focus on the original problem, and therefore keep the debug cycle short. Python is simple and easy to learn. We therefore propose pyosys, a script that generates Boost.Python wrappers around the C++ implementation of Yosys. These wrappers maintain seamless interoperability between C++ and Python. pyosys makes Python´s success accessible to Yosys: rapid application development. With pyosys, a user can interactively use Yosys in a Python session, with direct access to the Yosys data structures (e.g., design, modules, cells, wires) and methods (e.g., run pass, load plugin, get selection). In addition, the user can develop passes step- by-step directly in Python, with immediate feedback and debug capabilities. This is significant for scientists who can now test their algorithms using an easy-to-use and maintainable high- level language. The results of their experiments are stored in Python objects, and can be directly processed with data analysis frameworks like scipy, machine learning libraries such as TensorFlow, and data visualization frameworks like matplotlib.

Yosys is an open-source synthesis and verification tool which natively supports Verilog-2005 and offers a variety of passes to allow a user to adapt the design and verification flow. A user can extend the functionality of Yosys with a plugin interface in C++. C++ is a powerful language, and it is easy to lose track in fixing low-level issues like memory allocation, instead of focusing on the original problem. This can significantly increase the length of the compile/debug cycle. Python, on the other hand, is a dynamically-typed, garbage-collected language which takes away low-level management from the user, who can focus on the original problem, and therefore keep the debug cycle short. Python is simple and easy to learn. We therefore propose pyosys, a script that generates Boost.Python wrappers around the C++ implementation of Yosys. These wrappers maintain seamless interoperability between C++ and Python. pyosys makes Python´s success accessible to Yosys: rapid application development. With pyosys, a user can interactively use Yosys in a Python session, with direct access to the Yosys data structures (e.g., design, modules, cells, wires) and methods (e.g., run pass, load plugin, get selection). In addition, the user can develop passes step- by-step directly in Python, with immediate feedback and debug capabilities. This is significant for scientists who can now test their algorithms using an easy-to-use and maintainable high- level language. The results of their experiments are stored in Python objects, and can be directly processed with data analysis frameworks like scipy, machine learning libraries such as TensorFlow, and data visualization frameworks like matplotlib.