RFR: 8346657: Improve out of bounds exception messages for MemorySegments [v9]

[Maurizio Cimadamore]

On Tue, 18 Nov 2025 09:38:44 GMT, Igor Rudenko <duke at openjdk.org> wrote:

>> Logic for creating IndexOutOfBoundsException in MemorySegment is reworked:
>> - separate logic of checking bounds and constructing exception messages for both `access` and `slice` cases 
>> - idea presented in [JDK-8288534](https://bugs.openjdk.org/browse/JDK-8288534) slightly reworked with preservation of the original approach
>
> Igor Rudenko has updated the pull request incrementally with one additional commit since the last revision:
> 
>   improvements according to reviewer comments

The fundamental issue here is that `checkIndex` takes a bi-function for the exception generation. This forces client to resort to _instance_ methods if they want to embed more of their state description into the generated message. And this requires allocation -- which fundamentally is against the performance goals of the check bound routines in AbstractMemorySegmentImpl.

It would be better if Preconditions had more primitive, non-throwing variants which just returned true/false. Then we could easily implement whatever logic we wanted on top. Maybe we should look there first, and then come back to improve messages in the FFM API?

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PR Comment: https://git.openjdk.org/jdk/pull/28124#issuecomment-3547403406