RFR: 8352075: Perf regression accessing fields [v21]

[Radim Vansa]

On Thu, 5 Jun 2025 19:02:49 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> Radim Vansa has updated the pull request incrementally with three additional commits since the last revision:
>> 
>>  - Moved jtreg test
>>  - Improved documentation
>>  - Fix coding style (asterisk placement)
>
> src/hotspot/share/oops/fieldInfo.cpp line 285:
> 
>> 283:     FieldInfo fi;
>> 284:     reader.read_field_info(fi);
>> 285:     if (fi.field_flags().is_injected()) {
> 
> I thought that above, you only process java fields and not the injected fields?

`FieldInfoReader` is limited by the full stream, and after iterating through java fields it would start returning injected fields. For java fields we call the lookup below; we know that injected fields don't have a record in the table, and we know that there won't be any more java fields after we encounter the first injected field; that's why we `break` the cycle here.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24847#discussion_r2130366971