RFR: 8346657: Improve out of bounds exception messages for MemorySegments [v8]

[Maurizio Cimadamore]

On Mon, 17 Nov 2025 17:39:44 GMT, Chen Liang <liach at openjdk.org> wrote:

>> Igor Rudenko has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Adjust to TestMergeStoresMemorySegment.java requirements
>
> I don't think the two private interfaces approach works - since there is only one `RuntimeException apply(String, List)` in AMSI, JLS mandates a compile error, and even if we compile, JVMS says any of these two methods can be chosen regardless of casting.

> @liach Benchmark results for MacOS
> 
> **master**:
> 
> ```
> Benchmark                          (ELEM_SIZE)  Mode  Cnt   Score   Error  Units
> SegmentBulkHash.array                        8  avgt   30   1.962 ± 0.003  ns/op
> SegmentBulkHash.array                       64  avgt   30   3.701 ± 0.005  ns/op
> SegmentBulkHash.heapSegment                  8  avgt   30   3.121 ± 0.007  ns/op
> SegmentBulkHash.heapSegment                 64  avgt   30  12.982 ± 0.033  ns/op
> SegmentBulkHash.nativeSegment                8  avgt   30   2.901 ± 0.013  ns/op
> SegmentBulkHash.nativeSegment               64  avgt   30  12.825 ± 0.025  ns/op
> SegmentBulkHash.nativeSegmentJava            8  avgt   30   2.483 ± 0.007  ns/op
> SegmentBulkHash.nativeSegmentJava           64  avgt   30  26.347 ± 0.203  ns/op
> ```
> 
> **1095cf6**:
> 
> ```
> Benchmark                          (ELEM_SIZE)  Mode  Cnt   Score   Error  Units
> SegmentBulkHash.array                        8  avgt   30   1.968 ± 0.006  ns/op
> SegmentBulkHash.array                       64  avgt   30   3.713 ± 0.006  ns/op
> SegmentBulkHash.heapSegment                  8  avgt   30   3.125 ± 0.004  ns/op
> SegmentBulkHash.heapSegment                 64  avgt   30  12.998 ± 0.023  ns/op
> SegmentBulkHash.nativeSegment                8  avgt   30   2.917 ± 0.018  ns/op
> SegmentBulkHash.nativeSegment               64  avgt   30  12.868 ± 0.020  ns/op
> SegmentBulkHash.nativeSegmentJava            8  avgt   30   2.484 ± 0.006  ns/op
> SegmentBulkHash.nativeSegmentJava           64  avgt   30  26.324 ± 0.044  ns/op
> ```

Bulk operation is the worst benchmark to test impact of bound checks. I think something like LoopOverNonConstant is better.

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PR Comment: https://git.openjdk.org/jdk/pull/28124#issuecomment-3547344005