8357563: Shenandoah headers leak un-prefixed defines

[stefank]

We hit a compilation error in ZGC when we defined a constant NumPartitions. This happened because there is a define name NumPartitions inside shenandoahFreeSet.hpp. I propose that this (and its friends) are hid inside the ShenandoahRegionPartitions class, which is the only user of these defines. An alternative would be to prefix the define with something that is unlikely to clash with other parts of HotSpot.

This PR is my suggestion for a change to solve this so this name conflict. Does this seem like an acceptable solution, or do you want something else? Thanks!

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Issue

• JDK-8357563: Shenandoah headers leak un-prefixed defines (Enhancement - P4)

Reviewers

• Aleksey Shipilev (@shipilev - Reviewer)
• Kim Barrett (@kimbarrett - Reviewer)

Reviewing

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

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8357563: Shenandoah headers leak un-prefixed defines

Reviewed-by: shade, kbarrett

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At the time when this comment was updated there had been 58 new commits pushed to the master branch:

• 36f6d15: 8354517: Parallel: JDK-8339668 causes up to 3.7x slowdown in openjdk.bench.vm.gc.systemgc
• ae7ae84: 8356016: Build fails by clang(XCode 16.3) on macOS after JDK-8347719
• d6e4c5f: 8357506: [JVMCI] Consolidate eager JVMCI initialization code
• ... and 55 more: https://git.openjdk.org/jdk/compare/50a7755fa45529966373b58652c15975157ab846...master

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• shenandoah

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[shipilev]

Yes, this is fine. These should never have been in global scope, especially in the header that can easily be transitively included.

Actually, I would question even the type-casted triad, and probably a single constant would instead do. Leave it to a follow-up, if present problem blocks current development.

[shipilev]

@kdnilsen @earthling-amzn ^

[stefank]

FWIW, this doesn't block us, it just requires us to use a name that doesn't follow our naming convention, so if you have a better solution I'm OK with waiting for that.

[shipilev]

Nah, current version is fine. Folding this triad into a single constant would likely require dealing with signed-unsigned comparisons, casts back to enums, all that jazz. That would be a good starter task for our engineers.

[kimbarrett]

Looks good.

[stefank]

Thanks for reviewing! I'll go ahead and integrate this now.
/integrate

[openjdk]

Going to push as commit 68ee06f.
Since your change was applied there have been 59 commits pushed to the master branch:

• 0299588: 8343580: Type error with inner classes of generic classes in functions generic by outer
• 36f6d15: 8354517: Parallel: JDK-8339668 causes up to 3.7x slowdown in openjdk.bench.vm.gc.systemgc
• ae7ae84: 8356016: Build fails by clang(XCode 16.3) on macOS after JDK-8347719
• ... and 56 more: https://git.openjdk.org/jdk/compare/50a7755fa45529966373b58652c15975157ab846...master

Your commit was automatically rebased without conflicts.

[openjdk]

@stefank Pushed as commit 68ee06f.

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