RFR: 8334421: assert(!oldbox->is_unbalanced()) failed: this should not be called for unbalanced region

[Vladimir Kozlov]

On Mon, 24 Jun 2024 23:34:38 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

>> [JDK-8324969](https://bugs.openjdk.org/browse/JDK-8324969) changes was not complete. When Escape Analysis tries to determine if lock can be eliminated it looks only if corresponding object does not escape. I does not take into account if coarsening locks elimination already happened and created unbalanced regions.
>> 
>> Added check that not-escaped object is not referenced from an unbalanced region before marking or eliminating corresponding locks.
>> 
>> Dump additional information for coarsened locks when debugging.
>> 
>> New regression test was added
>> 
>> Tested tier1-5,stress,xcomp
>
> src/hotspot/share/opto/escape.cpp line 3505:
> 
>> 3503: // all compiled code paths have corresponding Lock/Unlock pairs.
>> 3504: bool ConnectionGraph::can_eliminate_lock(AbstractLockNode* alock) {
>> 3505:   BoxLockNode* box = alock->box_node()->as_BoxLock();
> 
> The definition can be moved under `EliminateNestedLocks` guard.

Done.

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PR Review Comment: https://git.openjdk.org/jdk/pull/19870#discussion_r1651775540