RFR: 8256657: Add cross-compiled build for Windows+Arm64 to submit workflow

[Bernhard Urban-Forster]

On Mon, 23 Nov 2020 12:01:14 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> This adds the cross-compiled build only, as no Windows+Arm64 machines are available on GitHub Action that we could use to run the tests.
>> 
>> Due to cross-compilation a build JDK is required. Initially I added EA builds to be downloaded from https://jdk.java.net/16/ and used for that, but then I saw how @shipiliv attempted it for the linux cross-compilation builds in https://github.com/openjdk/jdk/pull/1147.  That is using the JDK image produced by the x64 variant. This however add more stress to the "critical path", as now two more jobs depend on the x64 build first.
>> 
>> Let's see how it works out in the long-run. A Windows+AArch64 build takes 40-50min.
>
> I think you need to wait for #1350, and then reconcile this patch with that refactoring.

Thanks for all the comments.

> - 40-50 min builds seem to be excessive for just the hotspot build, do youknow what exactly takes that long? Is this for release and debug each or both combined?

It's for each of them. Installing a specific version of MSVC and creating the devkit take each ~10min. Thinking about it,  there is a opportunity to cache the devkit and do the MSVC installer invocation only if no cached devkit is available.

Here is an example run if you want to have a closer look:
https://github.com/lewurm/openjdk/runs/1434118318?check_suite_focus=true

> - Is it worth the cycles to build both release *and* debug? How probable is
it that a non-win-aarch-dev will break one but not the other? I presume
developers on the windows aarch project will have tested the build locally
before pushing.

Fair, I'll remove one of them (as suggested by Aleksey in another comment, I'll keep the debug one).

-------------

PR: https://git.openjdk.java.net/jdk/pull/1379