[CI][BYORTL] add Verilator regression test to CI

[vegaluisjose]

@tqchen @tmoreau89

[tmoreau89]

Thank you @vegaluisjose LGTM

[tqchen]

Thanks @vegaluisjose , looking at the files, looks like that libverilator.so needs to be shared cross stages. Merging this now would create a problem.

It would be great to not do so, and build the library before test (at the same stage)

[vegaluisjose]

Hey @tqchen ,

I don't think I am following, could you elaborate on what the problem will be?

The library is currently built when the CMAKE macro USE_VERILATOR_HW is ON. Also, during this stage the library is linked, so tvm knows where to find such library when selecting that backend in Python.

[tqchen]

Because the current mainline does not generate libverilator. The caching step will fail because we cannot found libverilator.

Sorry that i did not point in previous code review, and happy to discuss this further. Right now this PR has the following dependency:

• libtvm depends on libverilator.so When build with verilator runtime in set.

It would really be nice if the hw part can be built independently, and loaded on demand. So libtvm can load select and load the right version of libverilator when necessary. We can build the libverilator right at the test stage, with libtvm available.

We can explore a few ways to do that. One way I can think about, is as follows:

• move the runtime part src/runtime/contrib/verilator/ to the vta-hw, still include the json runtime, build and link against libtvm
• Use a load_dll function(like in https://github.com/apache/tvm-vta/blob/main/apps/tsim_example/python/tsim.py#L27, we can define in vta) to load the dll in store in global namespace, which will register the necessarily callbacks for the verilog json runtime
• Execute as normal.

Happy to chat more

[tmoreau89]

Preventing accidental merges

[liangfu]

It would really be nice if the hw part can be built independently, and loaded on demand.

+1

[vegaluisjose]

Hey guys,

The CI is updated now with the new version of Verilator backend. CI (Jenkins) seems to be working.

[tmoreau89]

That's great, thanks for making sure we land these verilator CI tests @vegaluisjose !

[tmoreau89]

Thank you @liangfu @tqchen @vegaluisjose ; the PR has been merged.