RFR: 8304693: Remove -XX:-UseVtableBasedCHA

[Coleen Phillimore]

On Wed, 26 Jun 2024 17:47:57 GMT, Vladimir Ivanov <vlivanov 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

Thanks for fixing the add_to_hierarchy code.

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.

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PR Review: https://git.openjdk.org/jdk/pull/19911#pullrequestreview-2142605312
PR Review Comment: https://git.openjdk.org/jdk/pull/19911#discussion_r1655309826