RFR: 8357079: Fix Windows AArch64 DevKit Creation

[Luigi Montoya]

On Sat, 14 Jun 2025 11:59:32 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>> I was thinking we could create the devkit based on the platform where the script is being run. For example, running `createWindowsDevkit.sh` on:
>> 
>> - Windows x64 would produce:
>>   - Native x86 libraries
>>   - Native x64 libraries
>>   - Cross-compiled aarch64 libraries
>> - Windows aarch64 would produce:
>>   - Native x86 libraries
>>   - Native x64 libraries
>>   - Native aarch64 libraries
>> 
>> From my analysis of your code suggestion, it looks like it might override the native aarch64 libraries and always set the cross-compiled ones. What do you think?
>
> I agree with your general premise, that the devkit should be created for the platform the devkit script is run on.
> 
> When you say that you should produce "native" x64 libraries on aarch64, do you mean that they should be run using x64 emulation? Otherwise you can't really have native x64 on aarch64... And even if that works, would it not be better to have pure native aarch64 cross-compiling to x64 (given that Microsoft in fact ships such compilers).

When you download the Visual Studio Build Tools on an ARM64 machine, it downloads the native binaries for the `x64` architecture under `Hostx64` and the native binaries for `arm64` under `Hostarm64`. This devkit script does not generate any binaries; it simply copies the Build Tools from Visual Studio.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25259#discussion_r2147426849