Enable Arm64 build in build pipeline

[gkhanna79]

With dotnet/coreclr#6000, we now generate Arm64 nuget packages for Windows. We should, now, build it in the pipeline.

@wtgodbe Can you PTAL? This should be similar to the x64 build definitions you have. For now please do not enable signing and publishing of the artifacts - just build.

[gkhanna79]

CC @weshaggard

[wtgodbe]

Do you expect us to ever want to sign binaries for an Arm64 build? If not, I can add logic to sign.builds to only sign binaries if the architecture is not Arm64, and we can reuse the same build definition that we use for x64. If not, I'll probably have to create another build definition (like the one we have for x86).

[weshaggard]

We will likely want to sign them at some point but I think it is better to disable them in the sign.builds file for now as opposed to creating new build definitions.

[wtgodbe]

@jhendrixMSFT what's the best way to apply this condition to sign.builds (only sign non-arm64 binaries)?

[jhendrixMSFT]

You should condition the FilesToSign item groups and targets GetFilesToSignItems and CleanUpMarkerFiles to be executed when BuildArch != arm64.

[wtgodbe]

I just queued an orchestrated build that should build arm64 Windows alongside x64. I'll update once the build completes.

[wtgodbe]

@gkhanna79 @weshaggard @jhendrixMSFT it looks like arm64 Windows builds require a toolset_dir to be passed in via the command line - do any of you guys have an example of what this looks like? Without it, the arm64 build fails.

[wtgodbe]

I see in netci.groovy we do "build.cmd /toolset_dir C:\ats2' - can we assume the same thing will work on our build machines?

[jhendrixMSFT]

@wtgodbe Seems unlikely as this directory doesn't exist on the build machines. What is it supposed to contain?

[wtgodbe]

I don't actually know, the documentation in build.cmd is very vague for it.

"arm64 builds currently use private toolset which has not been released yet"

"A toolset directory is required for the Arm64 Windows build. Use the toolset_dir argument."

@rahku do you know more about this?

[wtgodbe]

@jashook do you know anything about the 'toolset_dir' arg for arm64 windows builds? What is the directory supposed to contain? Where does it come from?

[rahku]

I have sent you link on how to do arm64 builds. build.cmd takes an extra param(toolset_dir) to set the environment for arm64 builds as neither VS nor cmake currently support arm64

[jashook]

Correct, at the moment a subset of the CI machines have this toolset directory installed and is referenced in our ci script accordingly.

[wtgodbe]

@jashook how can we go about getting this directory installed on our VSO build machines?