RFR: 8365190: Remove LockingMode related code from share

[Fredrik Bredberg]

On Wed, 3 Sep 2025 07:37:34 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

>> Since the integration of [JDK-8359437](https://bugs.openjdk.org/browse/JDK-8359437) the `LockingMode` flag can no longer be set by the user. After that, a number of PRs has been integrated which has removed all `LockingMode` related code from all platforms (except from zero, which is done in this PR).
>> 
>> This PR removes `LockingMode` related code from the shared (non-platform specific) files. It also removes the `LockingMode` variable itself.
>> 
>> Passes tier1-tier5 with no added problems.
>
> src/hotspot/share/runtime/basicLock.hpp line 51:
> 
>> 49:   void set_bad_metadata_deopt() { set_metadata(badDispHeaderDeopt); }
>> 50: 
>> 51:   static int displaced_header_offset_in_bytes() { return metadata_offset_in_bytes(); }
> 
> The `badDispHeaderDeopt` and `badDispHeaderOSR` constants should also be renamed.

Added this to o the [next cleanup](https://bugs.openjdk.org/browse/JDK-8365191).

> src/hotspot/share/runtime/synchronizer.cpp line 634:
> 
>> 632: }
>> 633: 
>> 634: static intptr_t install_hash_code(Thread* current, oop obj) {
> 
> A future RFE could potentially simplify and unify this with `FastHashCode`

Added this to o the [next cleanup](https://bugs.openjdk.org/browse/JDK-8365191).

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/27041#discussion_r2321495256
PR Review Comment: https://git.openjdk.org/jdk/pull/27041#discussion_r2321493463