Requiring a New Minimum VS Version for Windows/ARM64

[erik.joelsson at oracle.com]

Hello Ana,

This all sounds good to me. Adding something about this in 
doc/building.* would be nice.

/Erik

On 2021-12-15 12:27, Ana Marsh wrote:
> Hello,
>
> My name is Ana Marsh and I am a Software Engineer at Microsoft on the Java Engineering team. A few of my colleagues worked on the Windows AArch64 support commit <https://github.com/openjdk/jdk/commit/9604ee82690f89320614b37bfef4178abc869777#diff-f18c276bab77ace41193e6fb0b80752e18b8409815bd46546f936908ba10009f> in 2020 and now I am looking to revert one of their changes. Specifically, the change to src/hotspot/share/gc/g1/g1HeapRegionAttr.hpp. This change to g1HeapRegionAttr.hpp was added to provide a workaround for this MSVC bug<https://developercommunity.visualstudio.com/t/arm64-bad-code-generation-around-signed-char-arith/1079221> that has now been fixed in VS 16.8 and newer. As it stands now, Windows/ARM64 users must already be using VS 2019<https://github.com/microsoft/openjdk-aarch64#build-dependencies> (VS 16.0+), so reverting this change would consequently require users to have one of the last four minor versions of VS 2019 (16.8, 16.9, 16.10, 16.11) or VS 2022 (17.0+) with its release last month.
>
> I wanted to communicate this future change before submitting a Pull Request. I also plan on documenting the minimum required VS version for ARM64 in a comment in the build scripts. Let me know if you have any questions or concerns.
>
> Best,
>
> Ana
>