RFR: 8305895: Implement JEP 450: Compact Object Headers (Experimental) [v10]

[Thomas Stuefe]

On Mon, 9 Sep 2024 15:59:43 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> Roman Kennke has updated the pull request incrementally with six additional commits since the last revision:
>> 
>>  - More touch-ups, fix Shenandoah oop iterator
>>  - Remove asserts in XArrayKlass::oop_oop_iterate()
>>  - Various touch-ups
>>  - Improve is_oop()
>>  - Rename GCForwarding -> FullGCForwarding; some touch-ups
>>  - Fix comment
>
> src/hotspot/share/oops/compressedKlass.cpp line 116:
> 
>> 114:   _range = end - _base;
>> 115: 
>> 116:   DEBUG_ONLY(assert_is_valid_encoding(addr, len, _base, _shift);)
> 
> Can you refactor so the aarch64 path runs this same code without duplication?

In tinycp mode, aarch64 runs this code though? The aarch64 variant of pd_initialize just returns then. In non-COH mode (preexisting, not touched by this patch) Aarch64 needs its own handling.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20677#discussion_r1751866773