RFR: 8304693: Remove -XX:-UseVtableBasedCHA

[Vladimir Ivanov]

On Wed, 26 Jun 2024 18:00:12 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> JDK-8266074 introduced new CHA implementation and a flag (-XX:-UseVtableBasedCHA) to switch back to the original implementation for diagnostic purposes. Vtable-based CHA implementation has been turned on by default since 17 and now the time has come to remove UseVtableBasedCHA flag.
>> 
>> Testing: hs-tier1 - hs-tier6
>
> src/hotspot/share/runtime/arguments.cpp line 525:
> 
>> 523: 
>> 524:   { "HeapFirstMaximumCompactionCount", JDK_Version::undefined(), JDK_Version::jdk(24), JDK_Version::jdk(25) },
>> 525:   { "UseVtableBasedCHA",               JDK_Version::undefined(), JDK_Version::jdk(24), JDK_Version::jdk(25) },
> 
> We don't usually put diagnostic VM options in this table.

Ok, I was confused by the following comment before the table: 

 * To remove internal options (e.g. diagnostic, experimental, develop options), use
 * a 2-step model adding major release numbers to the obsolete and expire columns.

Does it make sense to adjust it as well?

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PR Review Comment: https://git.openjdk.org/jdk/pull/19911#discussion_r1655326163