RFR: 8357514: Disable AOT caching for runtime stubs [v2]

[Ioi Lam]

On Thu, 22 May 2025 04:56:37 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

>> After [JDK-8354887](https://bugs.openjdk.org/browse/JDK-8354887) was integrated we hit strange failures which looks like memory stomps during our JCK testing of AOT new JEPs:
>> 
>> # Internal Error (/workspace/open/src/hotspot/share/opto/regmask.hpp:222), pid=4186624, tid=4186658
>> # assert(_RM_UP[i] == 0) failed: _hwm too low: 5 regs at: 4
>> 
>> or
>> 
>> # Internal Error (/workspace/open/src/hotspot/share/opto/type.cpp:996), pid=2832821, tid=2832868
>> # fatal error: meet not symmetric
>> 
>> or other strange issues during C2 compilation
>> 
>> After investigating (running tests in loop) I narrowed down the issue to AOT caching of C2 runtime stubs:
>> 
>> https://github.com/openjdk/jdk/blob/master/src/hotspot/share/opto/output.cpp#L3491
>> 
>> After internal discussion we decided disable all runtime stubs caching.
>> There is no guarantee that we may not have issues with C1 stubs too.
>> 
>> I propose hard code AOTStubCaching flag to `false` value until the issue is solved.
>
> Vladimir Kozlov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Address comment

Marked as reviewed by iklam (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/25379#pullrequestreview-2859853854