enable windows arm64

[beckermr]

This is a tracking issue to enable windows arm64.

We think the path forward is to cross-compile and do out of band testing on native hardware.

Let's put todo items here:

• Remove CMAKE_GENERATOR and win cleanup conda-forge-pinning-feedstock#4357
• Add vs2022 as compiler for arm64 vs2022 for win-arm64 conda-forge-pinning-feedstock#4415
• Add compilers to vc-feedstock Win arm64 vc-feedstock#55
• set CMAKE vars vc-feedstock#58
• Support not running tests when cross compiling in win conda-smithy#1742
  • set BUILD_PLATFORM and TARGET_PLATFORM on windows conda-forge-ci-setup-feedstock#248
• Fix deprecated msvc_env_cmd in conda-build (make it a no-op for win-arm64 platform) Make msvc_env_cmd no-op for arm64 conda/conda-build#4867
  • Add gh4867.patch conda-build-feedstock#205
• Fix condaBasePath when useBundled is false, and there's no pre-existing conda conda-incubator/setup-miniconda#299
• set CROSSCOMPILING_EMULATOR conda-forge-ci-setup-feedstock#300
• Don't skip tests if there is an emulator conda-smithy#1808
• Build a python entrypoint launcher (cli-arm64.exe) for conda-build
  • Add win-arm64 support using cl.exe conda/conda-launchers#9
  • Add MSVC-built win-arm64 launcher conda/conda#14401
  • Add MSVC-built win-arm64 launchers conda/conda-build#5545
• Write a migrator like we did for linux-aarch64/linux-ppc64le resp. osx-arm64 (c.f. this file).
  • Initial list of packages in pinning repo Win-arm64 migration list conda-forge-pinning-feedstock#5440
  • Add win-arm64 migrator conda-forge-bot#3194
• cross-python for win_arm64? cross-python-feedstock#95

cc @zooba @isuruf @jakirkham @jezdez @chenghlee

[chenghlee]

x-refs for related ecosystem issues:

• Issue Support for Windows on Arm conda/conda#11472
• PR Add win-arm64 as a recognized platform conda/conda#11778
• PR Add win-arm64 as a recognized platform conda/conda-build#4579`
• Enable win-arm64 as a platform on anaconda.org ContinuumIO/anaconda-issues#12957

[isuruf]

@zooba I added a few TODOs above if you or someone else want to help.

[zooba]

@finnagin is looking at the conda-build changes, and will probably have some Qs about any user visible changes (such as how best to inform conda-build it should be doing a cross-compile). Hopefully that will unblock us to start looking at recipe/feedstock changes and figuring out the best way to automatically migrate existing ones (if needed).

[isuruf]

@zooba, @finnagin, task 4 needs to be done to build some packages. Task 5 is needed only after python itself is built.

[zooba]

Task 4 is definitely first, yeah, and part of that seems to be plugging in the arch and host_arch configs to allow running an ARM64 targeted build on AMD64 machine. That plus a few recipe updates should enable building Python - we don't actually need conda/conda-build itself to run natively (it'll be nice, but it's not essential).

[isuruf]

msvc_env_cmd is a deprecated function, so we need not update it to actually work. We just need it to not error out. So, a check for bits to see if it is arm64 and returning without doing anything should be enough.

[zooba]

@isuruf You mentioned in the call that you got the zlib build working. Can you post how you did that for @finnagin's benefit?

[isuruf]

See conda-forge/zlib-feedstock#72

conda build recipe -m .ci_support/win_arm64_.yaml

[zooba]

Ah neat, it's using CMake's support. I guess that means the env variables needed were already being set? Or did those get slipped in recently without me noticing?

[isuruf]

No, we should add support for an env variable like CMAKE_ARGS which we use in Linux/macOS. The two systems are so similar that even if cmake is not told that it is cross compiling, things just work because the correct compiler is used.

[zooba]

Oh cool, I didn't see where the compiler was being picked. Just a vcvarsall call? That should work for anything with MSBuild or setuptools (if relatively up to date) too.

[isuruf]

Just a vcvarsall call?

Yes.

C:\Program Files\Microsoft Visual Studio\2022\Enterprise>CALL "VC\Auxiliary\Build\vcvarsamd64_arm64.bat" -vcvars_ver=14.35 10.0.22621.0 

[finnagin]

Thanks @isuruf! This is very helpful!