[crac] RFR: 8368929: [CRaC] Move CPUFeatures check to C/R engine

[Radim Vansa]

On Wed, 1 Oct 2025 12:50:20 GMT, Jan Kratochvil <jkratochvil at openjdk.org> wrote:

>> How is this different from creating an arch-specific method with different implementations? To me that look just like a boilerplate (and the presence is only checked for currently compiled arch - so I won't make sure that the code work on all archs).
>
> It is true there are no target-specific files/classes. But there still can be:
> 
> class crac {
> static bool is_x86_64() {
> #ifdef __x86_64__
>   return true;
> #else
>   return false;
> #endif
>   };
> };
> if (is_x86_64()) {
>   ...
> }
> 
> Then all arch-specific code is compile-time checked on all arches.

The ifdef in here is doing exactly that - guarding a VM option that is defined only on x86_64... though it looks like the CI is compiling against the 'zero' architecture (which lacks the VM option despite the macro is defined).

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PR Review Comment: https://git.openjdk.org/crac/pull/266#discussion_r2398158611