RFR: 8364128: Improve gathering of cpu feature names using stringStream [v5]

[Ashutosh Mehra]

On Thu, 14 Aug 2025 07:36:13 GMT, Yudi Zheng <yzheng at openjdk.org> wrote:

>> Ashutosh Mehra has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Address review comments
>>   
>>   Signed-off-by: Ashutosh Mehra <asmehra at redhat.com>
>
> src/hotspot/cpu/aarch64/vm_version_aarch64.hpp line 148:
> 
>> 146: 
>> 147:   enum Feature_Flag {
>> 148: #define DECLARE_CPU_FEATURE_FLAG(id, name, bit) CPU_##id = bit,
> 
> It would be greatly appreciated if you could give the Graal devs a heads-up when changing CPU feature flags. JVMCI sees different CPU features with this change, and eventually leads to SIGILL by generating instruction not supported by the underlying CPU.

@mur47x111 sorry for breaking JVMCI with this. I was not aware of such a dependency at all and I touched this code for the first time. For future work, how do I check if my change in hotspot has the potential to break JVMCI? And what is the best forum to inform about such changes?

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PR Review Comment: https://git.openjdk.org/jdk/pull/26515#discussion_r2276753999