[lworld] Integrated: 8341771: [lworld] Heap dump recognizing new flat fields formats

[Alex Menkov]

On Fri, 24 Oct 2025 00:57:03 GMT, Alex Menkov <amenkov at openjdk.org> wrote:

> The fix re-implements flat object support in heap dumper.
> New approach does not require changes in .hprof format.
> Flat value objects are dumped as heap-allocated objects with generated ID.
> For heap-allocated objects the ID is their address (oop), they are always aligned.
> ID generator for flat objects uses unaligned values (so there is no conflicts with oops).
> 
> HeapDump test was reimplemented (it was disabled for a long time)
> Changes in hprof test lib were reverted (they are not needed anymore)
> 
> testing: tier1..4,hs-tier5-svc

This pull request has now been integrated.

Changeset: 296fe862
Author:    Alex Menkov <amenkov at openjdk.org>
URL:       https://git.openjdk.org/valhalla/commit/296fe862f73ad92093d62372141dc848a3e42d72
Stats:     1418 lines in 10 files changed: 295 ins; 941 del; 182 mod

8341771: [lworld] Heap dump recognizing new flat fields formats
8328468: [lworld] Reimplement HeapDump test for JEP401
8317416: [lworld] JDK-8306441 (Two phase segmented heap dump) needs Valhalla support

Reviewed-by: fparain

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PR: https://git.openjdk.org/valhalla/pull/1700