Add initial support for FreeBSD.arm64

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Based on discussion started in #71338, this PR integrate changes needed to start building runtime for FreeBSD arm64 (aka aarch64) host. Work is still in progress, but it would be nice to hear any feedback if changes are done in alignment with current build system.

cc @wfurt@Thefrank@janvorli@am11

[am11]

@sec, great progress!

Please revert eng/native/configuretools.cmake changes as they are not needed after #71446.

Q: Do we want to add FreeBSD 12 RID as well? We are adding support for both 12 and 13 in arcade.

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Changes reverted. As for 12 vs 13 - starting from 13, arm64 is Tier1 support, 12 is Tier2 - don't know if the question was to me though :)

[wfurt]

generally looks good to me but it seems to break current FreeBSD pipeline....

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generally looks good to me but it seems to break current FreeBSD pipeline....

Looks like fixed by c0c5dea :)

[am11]

Nice! 👍

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Would it also be OK to include those changes - https://gist.github.com/sec/150cda0763a2b9ddc45429ee942ff3c0 - they add arm64 RID is similar places as freebsd-x64 ones and also bring back crossgen2 package generation for FreeBSD which was disabled in recent commits (maybe there was a reason for that - introduced in here 7ff3ac6#diff-115c40d5f6cdfb8ebea1490c13581e76b60c3430cbf13f45c270fc5ec383daff) ?

[am11]

I think it is reasonable to include those changes. crossgen2 build now has three modes, one of which is selected based on the platform:

• NativeAOT - build compiles clr, nativeaot and crossgen2 then publishes CG2 with -p:PublishAot=true.
• SingleFile - on platforms where NativeAOT is not yet supported (macOS, FreeBSD, illumos), build compiles clr, nativeaot and CG2 then publishes CG2 with -p:PublishSingleFile=true.
• Disabled: on platforms where CG2 is not yet ported (illumos), build skips CG2 and steps which depend on CG2 altogether.

On FreeBSD, we should be publishing CG2 as a singlefilehost executable.

[am11]

You can also enable CG2 in a separate PR, if you want (will give you more time to test with docker image, once dotnet/arcade#9834 is merged and dotnet/dotnet-buildtools-prereqs-docker produces the image).

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Doing simple return 0 inside this method also makes SDK work, but, does this block this changes to be merged? It's still not supported, same as x64.

@Thefrank I can provide you SSH access to real ARM64 box with FreeBSD on it - if you have time, just email me public key and I will get you up and running :)

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Any chance to get this merged, shouldn't break anything, but will help me having arm64 builds in sync without doing constant merge/conflicts fix between branches :) ?

[janvorli]

LGTM, thank you! I am sorry for the long delay.

[janvorli]

I'm re-running the CI tests to get it green so that it can be merged.

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@janvorli Thanks! I see there are some failures regarding --targetos, something I broke, pushed change that should fix that.

edit: looks like fixed, builds are green :)

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Is there anything more needed in this PR to make it happen, @MichalStrehovsky?

[MichalStrehovsky]

Is there anything more needed in this PR to make it happen, @MichalStrehovsky?

I'm only pinged as a code owner because of the change to src/coreclr/nativeaot/BuildIntegration/Microsoft.NETCore.Native.targets. That change looks okay to me although I don't understand why we need it without #80323 (those targets are NativeAOT specific).