RFR: 8357079: Fix Windows AArch64 DevKit Creation

[Luigi Montoya]

On Mon, 16 Jun 2025 13:38:34 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>> 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.
>
> I find this confusing, but that's probably since I don't understand what Microsoft is shipping and where.
> 
> There are 4 relevant compilers:
> 1) A compiler that runs on x64 and generates x64 code (x64 native compilation)
> 2) A compiler that runs on x64 and generates aarch64 code (aarch64 cross-compilation on x64)
> 3) A compiler that runs on aarch64 and generates aarch64 code (aarch64 native compilation)
> 4) A compiler that runs on aarch64 and generates x64 code (x64 cross-compilation on aarch64)
> 
> For a devkit targeting x64, 1) and 2) should be included. For a devkit targeting aarch64, 3) (and ideally 4) as well) should be included. 
> 
> Are you saying that if you download VS on aarch64, you will get all four compilers installed?

Yes, if I download VS on aarch64 I get the four compilers installed.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25259#discussion_r2150506976