8373442: [lworld] Fix CDS heap dumping crashes

[coleenp]

This fixes three crashes in when heap dumping is enabled with Matias's patch.
Tested with tier1-3, that doesn't exactly turn on valhalla and some --enable-valhalla testing locally.

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Progress

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Issue

• JDK-8373442: [lworld] Fix CDS heap dumping crashes (Bug - P4)

Reviewers

• Ioi Lam (@iklam - Committer) ⚠️ Review applies to 19437153
• Matias Saavedra Silva (@matias9927 - Committer)

Reviewing

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[bridgekeeper]

👋 Welcome back coleenp! A progress list of the required criteria for merging this PR into lworld will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@coleenp This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8373442: [lworld] Fix CDS heap dumping crashes

Reviewed-by: iklam, matsaave

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At the time when this comment was updated there had been 120 new commits pushed to the lworld branch:

• 651a8fe: 8367623: [lworld] C2: Ideal Optimization on InlineTypeNode should not be carried out after Macro Expansion
• 87dc27c: 8372304: [lworld] Test serviceability/jvmti/valhalla/HeapDump/HeapDump.java fails in product build
• 96dd748: Merge
• ... and 117 more: https://git.openjdk.org/valhalla/compare/30ef92b23a8cde9306e36c089c09ec669d3c4d20...lworld

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the lworld branch, type /integrate in a new comment.

[mlbridge]

Webrevs

• 01: Full - Incremental (c01ef0a2)
• 00: Full (19437153)

[iklam]

Why is Arguments::enable_preview() check necessary here but not in aotMappedHeapWriter.cpp‎?

[coleenp]

Yes, these should fail too.
Edit. No they don't fail because they test Universe::objectArrayKlass() which is a default RefArrayKlass and that class doesn't set any special flattening or other bits in the markWord, so markWord::prototype() is okay there. But this code is confusing and fragile and should be rewritten.

[coleenp]

It should be refactored in mainline now that Valhalla uses Klass::_prototype_header, like COH, we should always use it unconditionally for object allocation. Not for this PR though, this is to get things working.

[matias9927]

LGTM, thanks!

[coleenp]

Thanks for reviewing Ioi and Matias.
/integrate

[openjdk]

Going to push as commit cf0c0c0.
Since your change was applied there have been 121 commits pushed to the lworld branch:

• 40958cc: 8373284: [lworld] More tests could be rewritten with LayoutKindHelper
• 651a8fe: 8367623: [lworld] C2: Ideal Optimization on InlineTypeNode should not be carried out after Macro Expansion
• 87dc27c: 8372304: [lworld] Test serviceability/jvmti/valhalla/HeapDump/HeapDump.java fails in product build
• ... and 118 more: https://git.openjdk.org/valhalla/compare/30ef92b23a8cde9306e36c089c09ec669d3c4d20...lworld

Your commit was automatically rebased without conflicts.

[openjdk]

@coleenp Pushed as commit cf0c0c0.

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