8374882: [lworld] Update hierarchies in oopsHierarchy.hpp

[jsikstro]

Hello,

The hierarchies in oopsHierarchy.hpp are not up to date with the actual class hierarchies in the implementation. I've refered to these a couple of times and stumble on the fact that they are not accurate.

I've tested that this builds locally.

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Issue

• JDK-8374882: [lworld] Update hierarchies in oopsHierarchy.hpp (Enhancement - P4)

Reviewers

• Paul Hübner (@Arraying - Committer) ⚠️ Review applies to 94d2e61b
• Axel Boldt-Christmas (@xmas92 - Committer)
• Frederic Parain (@fparain - Committer)

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8374882: [lworld] Update hierarchies in oopsHierarchy.hpp

Reviewed-by: phubner, aboldtch, fparain

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At the time when this comment was updated there had been 2 new commits pushed to the lworld branch:

• 1ecc74b: 8374887: [lworld] Cleanup around vgetfield/vputfield for x86
• ab311a7: 8374913: [lworld] UnProblemList three tests due to JDK-8372341

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• 01: Full - Incremental (dbad21f1)
• 00: Full (94d2e61b)

[Arraying]

Long overdue, thanks for doing this. Makes it clear that the refArrayOopDesc is a bit special.

[fparain]

Shouldn't refArrayOopDesc be aligned with flatArrayOopDesc?

[Arraying]

I don't think so:
class refArrayOopDesc : public arrayOopDesc {

[fparain]

But :
class RefArrayKlass : public ObjArrayKlass
So there's an unconsistency here, refArrayOopDesc should be a subclass of objArrayOopDesc.

[jsikstro]

I agree that it would be clearer to make refArrayOopDesc inherit from objArrayOopDesc. I'll run some tests to see if it's a simple "switch" to inherit from objArrayOopDesc instead. If it's a trivial change I can add it to this PR and change the hierarchy in oopsHierarchy.hpp, otherwise I suggest we should handle that in a follow-up.

[jsikstro]

I've ran Oracle's tier 1-4, hotspot_valhalla and jdk_valhalla with refArrayOop inheriting from objArrayOop instead, which looks good. As it is a simple "switch", I'll go ahead and do that in this PR. I also made some spelling fixes to the description of refArrayOop.

[xmas92]

lgtm.

[fparain]

Thank you for the re-parenting of refArrayOop.
Looks good to me.