RFR: 8334866: Improve Speed of ElfDecoder source search [v8]

[Christian Hagedorn]

On Thu, 30 Oct 2025 11:46:11 GMT, Kerem Kat <krk at openjdk.org> wrote:

>> Right now, looking up source file and line number info is slow because we do a full linear scan of the `.debug_aranges` section for every single call. This can be a major bottleneck on large binaries, especially during frequent native stack walking, e.g. while writing an hs_err.
>> 
>> This change fixes that by caching the address ranges on the first lookup, and keeping it in memory for the lifetime of the `DwarfFile` object.
>> 
>> All subsequent lookups on that object now use a binary search instead of the slow linear scan. If caching fails for any reason, it just falls back to the old method.
>
> Kerem Kat has updated the pull request incrementally with three additional commits since the last revision:
> 
>  - Revert "Erase obsolete comments"
>    
>    This reverts commit 860b6ee6faeb6e56e292abef1c85faad456729e2.
>  - fix space
>  - Erase obsolete comments

Marked as reviewed by chagedorn (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/27337#pullrequestreview-3399355949