Re: modified BPF backend, a request for consideration

Re: modified BPF backend, a request for consideration

[Alexei Starovoitov]

On Wed, Jul 14, 2021 at 7:58 PM Dmitri Makarov <dmitri@solana.com> wrote:
>
> Hi Alexei,
>
> I work on an llvm-based compiler with modified BPF backend. Our changes are incompatible with the BPF verifier. However, I added a target feature that isolates our changes from the main BPF backend. My organization is interested in integrating our changes into the main llvm repository to simplify keeping our llvm-based toolchain updated with the new llvm releases. I realize our changes are not interesting for BPF maintainers/code owners, but would you maybe consider some path for accepting our modified BPF Target if it's not affecting the main (and only) BPF Target?  What would be your recommendation for us to move forward with this?

It's hard to say without looking at the changes.
For example, new instructions, optimization passes, custom debug-info are all
within scope of what can be added. The verifier might not understand
these things today,
but if it fits the path where BPF ISA might end up in the future we can come up
with a way to land it.
So please submit a diff for llvm repo and cc these folks.