Provide C API for Spike Integration with Other Languages

[Clo91eaf]

Background:

Spike, being a fundamental component within the RISC-V ecosystem, possesses extensive capabilities in simulation and emulation. To broaden its accessibility and interoperability with various programming languages, it's imperative to develop a C API for Spike, enabling seamless integration with other language environments. A preliminary effort has been made in the libspike-interfaces project, demonstrating a basic Rust binding usage.

Proposal:

1. Development of a C API for Spike: In order to facilitate integration with different programming languages, it's essential to define and expose certain Spike objects via a C API. This API will serve as a bridge for communication between Spike and other language environments, enabling developers to leverage Spike's functionalities across diverse platforms.

2. Additional Usage Scenarios:

   • RISC-V Bus Behavior Model
   • Trace-based Performance Model
   • Co-simulation for Verification

Roadmap:

• Serialization and Deserialization Support: Introducing serialization and deserialization support will facilitate architecture injection, enabling flexible and customizable system configurations.
• Support for Undefined Behavior: Providing support for handling undefined behavior via hooks ensures robustness and reliability in simulation scenarios.
• Custom Instruction Support Hooks: Enabling the definition and integration of custom instructions enhances Spike's extensibility and versatility for specialized use cases.

[jerryz123]

Most of what you describe would be best implemented in a separate library that links to Spike. Recent work has made using spike as-a-library easier, there are even regressions now to test that this works.

Do you have concrete examples of changes/improvements that would improve the usability of Spike in these ways?

Co-simulation for Verification

There are already a number of projects which link Spike in the RTL simulator to provide functional co-simulation for verification.

Custom Instruction Support Hooks

This is already supported, but the APIs are not well documented.