RFR: 8368897: RISC-V: Cleanup RV_EXT_FEATURE_FLAGS & RV_NON_EXT_FEATURE_FLAGS [v4]

[Robbin Ehn]

On Wed, 1 Oct 2025 10:34:28 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> Hi,
>> Can you help to review the patch?
>> 
>> This patch cleans up RV_EXT_FEATURE_FLAGS & RV_NON_EXT_FEATURE_FLAGS, as discussed https://github.com/openjdk/jdk/pull/27152#discussion_r2367109820:
>> * reorder flags in alphabetic order for RV_EXT_FEATURE_FLAGS
>> * move comments close to feature declaration for RV_EXT_FEATURE_FLAGS & RV_NON_EXT_FEATURE_FLAGS
>> 
>> We also discussed (https://github.com/openjdk/jdk/pull/27171#discussion_r2387195562) the assert introduced in https://github.com/openjdk/jdk/pull/24094, previously we think this will restrict the flags order in RV_EXT_FEATURE_FLAGS, but I found out that this  assert (<del>is not necessary</del>, so we should be able to order flags in RV_EXT_FEATURE_FLAGS in any way we'd like to) does not work as expected, will fix this in another pr.
>> 
>> Thanks!
>
> Hamlin Li has updated the pull request incrementally with one additional commit since the last revision:
> 
>   order RV_NON_EXT_FEATURE_FLAGS

Hey, I don't get the premise.

VMVersion have a bunch of methods e.g VM_Version::supports_data_cache_line_flush() / VM_Version::get_current_sve_vector_length, etc....
Now we call some of them "non_ext_UnalignedScalar()", why ? And how is this a improvement ?

VM_Version methods is not related to whatever or not some information we need is part of an RVI extension.

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PR Comment: https://git.openjdk.org/jdk/pull/27562#issuecomment-3371395516