Yosys newer versions add $scopeinfo cells for debugging purposes

[ThVerg]

Yosys newer versions add $scopeinfo cells for debugging purposes so it would be nice to add the proper cleanup to remove them before writting the JSON output in order for the NextPNR not to fail.

[KelvinChung2000]

Did nextpnr complain about the cell not being mapped?

[ThVerg]

Sorry for not posting it earlier. Compeletely my bad.

ERROR: Unable to place cell 'top_i', no BELs remaining to implement cell type '$scopeinfo'
0 warnings, 1 error

ERROR | CalledProcessError | Command 'FAB_ROOT=/home/theofanis/Musik/FABulous/Temp /usr/bin/nextpnr-generic --uarch fabulous --json /home/theofanis/Musik/FABulous/Temp/user_design/sequential_16bit_en.json -o fasm=/home/theofanis/Musik/FABulous/Temp/user_design/sequential_16bit_en.fasm --verbose --log /home/theofanis/Musik/FABulous/Temp/user_design/sequential_16bit_en_npnr_log.txt' returned non-zero exit status 255.
ERROR | Command 'place_and_route user_design/sequential_16bit_en.json' execution failed with exit code 1
ERROR | PipelineCommandError | Command failed

[KelvinChung2000]

Which version of yosys are you using?

[ThVerg]

Recently updated to Yosys 0.55

[KelvinChung2000]

Strange, $scopeinfo has been the default since 0.49. The release is Jan 21, 2025, and we have not encountered any issues. Could be something due to nextpnr. We will look into the root cause. I think for now you can either alter the synthesis script to add a -noscopeinfo at the write_json pass. Or just do a quick Python script to remove the $scopeinfo entry.

[ThVerg]

Yeah, i have already done that and its working properly i think. I reported the issue just so you can fix it for everyone by default.

[IAmMarcelJung]

What is your exact setup (OS, installation method, nextpnr version)? Seems like this is quite an edge case since none of us ever encountered this issue, so we would need more information on how to replicate it.

However I remember that I had a similar issue when using Yosys and nextpnr for Artix-7 bitstream generation, so it's not completely new to me.