Native ARM support

[henryiii]

Does this support the new Windows ARM runners? If so, then the readme should be updated, as it only lists the Intel archs under native. If not, then it should then the readme should be updated. :)

(Edit: this does not support native running)

[pzhlkj6612]

Hi! I've seen the "windows-11-arm" GitHub runner in About GitHub-hosted runners - GitHub Docs. However, there does not seem to be any instruction about ARM64 native building in Use the Microsoft C++ toolset from the command line | Microsoft Learn. I haven't played with VC++ recently, so please correct me if I'm wrong.

[henryiii]

I think you currently want to use amd64_arm64 if you are on arm64, from what I understand. It's okay to use an emulated compiler targeting the native architecture. Because it works just fine without a large performance issue, there isn't a native build from my undertanding. (More info in pypa/cibuildwheel#2364, I'm just guessing based on that issue plus the above MS learn link) I think the problem is this action is trying to target amd64 from arm64 by default.

[jdpurcell]

I also noticed the Microsoft documentation page doesn't mention native ARM64, but inspecting the contents of the vcvarsall.bat file for VS2022 reveals:

if /I "%1"=="arm64" (
    set __VCVARSALL_TARGET_ARCH=arm64
    set __VCVARSALL_HOST_ARCH=arm64
    set __local_ARG_FOUND=1
)

I made use of it in a build script and it seemed to work fine. Note that $env:buildArch is something I define manually in my workflow YAML, it's not automatically set.

[streetpea]

Here is the blog post announcing native arm support in 2022: https://devblogs.microsoft.com/visualstudio/arm64-visual-studio-is-officially-here/. You can also see it referenced in the docs here: https://learn.microsoft.com/en-us/visualstudio/install/visual-studio-on-arm-devices?view=vs-2022. It looks like the installer should automatically tell if you're running arm and use that build from this snippet of the documentation:

With the Visual Studio 2022 version 17.4 release or later, you can access the new native Arm64 MSVC (Microsoft Visual C++) compiler toolset, including C++ Code Analysis, while still targeting all platforms currently supported by MSVC.

I tried:

      - name: Setup MSVC
        uses: ilammy/msvc-dev-cmd@v1
        with:
          arch: arm64

and it seemed to use the arm build of msvc