RFR: 8364588: Export the NPE backtracking functionality to general null-checking APIs [v4]

[Chen Liang]

On Tue, 23 Sep 2025 22:43:53 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Chen Liang has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Update NPE per roger review
>
> src/hotspot/share/interpreter/bytecodeUtils.cpp line 205:
> 
>> 203:     // A slot is found
>> 204:     FOUND
>> 205:   };
> 
> So you define an ENUM to capture the negative cases but then you can use any int >= 0 and pretend it is a member of the enum. ?? Is that typical C++ enum usage?

This was from @jdksjolen's suggestion. I emulated how valhalla's LayoutKind is declared.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26600#discussion_r2373654413