Apicula/Windows build is broken

[zapta]

Version

Yosys 0.63+89 (git sha1 de99d67bb-dirty, aarch64-apple-darwin23.5-clang++ 18.1.8 -fPIC -O3)

On which OS did this happen?

macOS

Reproduction Steps

Use the oss-cad-suite release of 2026-03-11 and run

gowin_pack -d GW2A-18C -o _build/tang20k/hardware.fs _build/tang20k/hardware.pnr.json

The input file
hardware.pnr.json

The input file was generated using

yosys -p "synth_gowin -top main -json _build/tang20k/hardware.json ; write_verilog _build/tang20k/yosys-synth.v" -q -DSYNTHESIZE ftdi_tx_fifo.v main.v ftdi/async_fifo/async_fifo.v ftdi/async_fifo/fifomem.v ftdi/async_fifo/rptr_empty.v ftdi/async_fifo/sync_r2w.v ftdi/async_fifo/sync_w2r.v ftdi/async_fifo/wptr_full.v testing/test_utils.v utils/pll.v utils/pulse_stretcher.sv utils/reset_gen.v utils/ws2812.v

nextpnr-himbaechel --device GW2AR-LV18QN88C8/I7 --json _build/tang20k/hardware.json --write _build/tang20k/hardware.pnr.json --report _build/tang20k/hardware.pnr --vopt family=GW2A-18C --vopt cst=pinout.cst -q --seed 1008

Expected Behavior

gowin_pack completes with no warnings.

Actual Behavior

The gowin_pack commands prints two warnings about missing python modules.

gowin_pack -d GW2A-18C -o _build/tang20k/hardware.fs _build/tang20k/hardware.pnr.json
/Users/user/.apio/packages/oss-cad-suite/lib/python3.11/site-packages/apycula/bitmatrix.py:60: UserWarning: Numpy is not available, performance will be degraded.
  warnings.warn("Numpy is not available, performance will be degraded.")
/Users/user/.apio/packages/oss-cad-suite/lib/python3.11/site-packages/apycula/crc16.py:19: UserWarning: fastcrc is not available, performance will be degraded.
  warnings.warn("fastcrc is not available, performance will be degraded.")

[zapta]

@pepijndevos, is this issue related to this PR? YosysHQ/apicula#453

[pepijndevos]

Yes the warning means exactly what it says: installing those packages will speed up packing significantly.

We moved towards pure python to make it easy for projects like osscadsuite to bundle it but now we added back optional C deps that speed things up significantly.

This would ideally be handled by osscadsuite

[zapta]

Can you remove the warnings until oss cad suite will add the missing packages?

…

On Wed, Mar 11, 2026 at 10:57 PM Pepijn de Vos ***@***.***> wrote: *pepijndevos* left a comment (YosysHQ/oss-cad-suite-build#194) <#194 (comment)> Yes the warning means exactly what it says: installing those packages will speed up packing significantly. We moved towards pure python to make it easy for projects like osscadsuite to bundle it but now we added back optional C deps that speed things up significantly. This would ideally be handled by osscadsuite — Reply to this email directly, view it on GitHub <#194 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAQVMQNUG76SHDEODSLHK6L4QJGVJAVCNFSM6AAAAACWO6DNP6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DANBUGE4TCMJUGI> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[pepijndevos]

Why? The warning is accurate, and it's just a warning.

[zapta]

Because they provide no value to users and are confusing. The warnings suggest that something is wrong but the users cannot do anything about them except filing an issue with I already did.

'Just a warning' is also something that attracts and distracts users attention and the matter here is 100% internal implementation details that should be transparent to users.

Please consider to remove them.

[KrystalDelusion]

Why are you raising this on the Yosys repo? This has nothing to do with Yosys. Go raise it on Apicula if you have an issue with it, or on oss-cad-suite if you want the packages added there.

[pepijndevos]

Nothing stops you from installing libraries in your Oss cad suite environment https://github.com/YosysHQ/oss-cad-suite-build?tab=readme-ov-file#using-litex eg python3 -m pip install numpy fastcrc or even their special tabbypip

[zapta]

Thanks @pepijndevos. This is doable but the idea behind oss-cad-suite is simple installation of the open source tool chains without too many manual steps. I would be nice if you can take care of it.

Something more serious, gowin_pack now fails completly on windows (I am using oss-cad-suite 2026-03-11). It doesn't find msgspec and fallback to msgpack but it is also missing (it does work on linux and macos).

The failure log

[OSS CAD Suite] C:\Users\User\work>gowin_pack.exe -d GW1N-9C -o _build\default\hardware.fs _build\default\hardware.pnr.json
C:\Users\User\Downloads\oss-cad-suite\lib\python3.11\site-packages\apycula\bitmatrix.py:60: UserWarning: Numpy is not available, performance will be degraded.
  warnings.warn("Numpy is not available, performance will be degraded.")
C:\Users\User\Downloads\oss-cad-suite\lib\python3.11\site-packages\apycula\chipdb.py:232: UserWarning: Msgspec is not available, performance will be degraded.
  warnings.warn("Msgspec is not available, performance will be degraded.")
Traceback (most recent call last):
  File "C:\Users\User\Downloads\oss-cad-suite\lib\python3.11\site-packages\apycula\chipdb.py", line 216, in <module>
    import msgspec
ModuleNotFoundError: No module named 'msgspec'
 
During handling of the above exception, another exception occurred:
 
Traceback (most recent call last):
  File "C:\Users\User\Downloads\oss-cad-suite\bin\gowin_pack-script.py", line 33, in <module>
    sys.exit(load_entry_point('Apycula==0.30.dev11+g67f38ca94', 'console_scripts', 'gowin_pack')())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\User\Downloads\oss-cad-suite\bin\gowin_pack-script.py", line 25, in importlib_load_entry_point
    return next(matches).load()
           ^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\User\Downloads\oss-cad-suite\lib\python3.11\importlib\metadata\__init__.py", line 202, in load
    module = import_module(match.group('module'))
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\User\Downloads\oss-cad-suite\lib\python3.11\importlib\__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1204, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1176, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1147, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 690, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 940, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "C:\Users\User\Downloads\oss-cad-suite\lib\python3.11\site-packages\apycula\gowin_pack.py", line 12, in <module>
    from apycula import chipdb
  File "C:\Users\User\Downloads\oss-cad-suite\lib\python3.11\site-packages\apycula\chipdb.py", line 233, in <module>
    import msgpack
ModuleNotFoundError: No module named 'msgpack'

Searching for msgpack.py in oss-cad-suite

~/Downloads/oss-cad-suite$ find . | grep msgpack
./lib/python3.11/site-packages/apycula/GW1N-1.msgpack.xz
./lib/python3.11/site-packages/apycula/GW1N-4.msgpack.xz
./lib/python3.11/site-packages/apycula/GW1N-9.msgpack.xz
./lib/python3.11/site-packages/apycula/GW1N-9C.msgpack.xz
./lib/python3.11/site-packages/apycula/GW1NS-4.msgpack.xz
./lib/python3.11/site-packages/apycula/GW1NZ-1.msgpack.xz
./lib/python3.11/site-packages/apycula/GW2A-18.msgpack.xz
./lib/python3.11/site-packages/apycula/GW2A-18C.msgpack.xz
./lib/python3.11/site-packages/apycula/GW5A-25A.msgpack.xz
./lib/python3.11/site-packages/apycula/GW5AST-138C.msgpack.xz
./lib/python3.11/site-packages/pip/_vendor/msgpack
./lib/python3.11/site-packages/pip/_vendor/msgpack/exceptions.py
./lib/python3.11/site-packages/pip/_vendor/msgpack/ext.py
./lib/python3.11/site-packages/pip/_vendor/msgpack/fallback.py
./lib/python3.11/site-packages/pip/_vendor/msgpack/__init__.py
./lib/python3.11/site-packages/pip/_vendor/msgpack/__pycache__
./lib/python3.11/site-packages/pip/_vendor/msgpack/__pycache__/exceptions.cpython-311.pyc
./lib/python3.11/site-packages/pip/_vendor/msgpack/__pycache__/ext.cpython-311.pyc
./lib/python3.11/site-packages/pip/_vendor/msgpack/__pycache__/fallback.cpython-311.pyc
./lib/python3.11/site-packages/pip/_vendor/msgpack/__pycache__/__init__.cpython-311.pyc

This is a major regression for the gowin tool chain, can you please take care of it?

If you want me to move this issue to another repo please let me know which one.

[pepijndevos]

Apparently oss cas suite updated apycula without updating its dependencies. That's not something I can fix on the apicula side. Have you reported this with them? I can try to find time to make a pr.

[whitequark]

I migrated the issue to oss-cad-suite-build repo.

[zapta]

Thanks @whitequark!

@pepijndevos, ideally apicula will be able to tell oss-cad-suite automatically what modules and dependencies it needs, similar to requirements.txt with python modules.