8379614: [lworld] runtime/valhalla/inlinetypes/InlineTypeDensity.java fails with UCOH

[caspernorrbin]

Hi everyone,

The test InlineTypeDensity.java builds on incorrect assumptions that a null restricted non-atomic value class is identical to a primitive type, which is not necessarily the case. For example, the first element of an array has to be aligned to 64 bits, while in a primitive type it does not. With COH enabled, this causes the test to fail, as the value class becomes bigger than its primitive equivalent.

I have reworked this test to instead check that everything is flattened as expected, and that the alignment of the first element is correctly 64 bits. With these changes, I have also removed vm.flagless which makes us able to run this test in more configurations.

Testing:

• Tiers 1-3
• Manual runs of the test with different flag combinations.

---

Progress

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Issue

• JDK-8379614: [lworld] runtime/valhalla/inlinetypes/InlineTypeDensity.java fails with UCOH (Bug - P4)

Reviewers

• Stefan Karlsson (@stefank - Committer)
• Frederic Parain (@fparain - Committer)

Reviewing

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

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

8379614: [lworld] runtime/valhalla/inlinetypes/InlineTypeDensity.java fails with UCOH

Reviewed-by: stefank, fparain

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At the time when this comment was updated there had been 3 new commits pushed to the lworld branch:

• 788bb28: 8380084: [lworld] Implement value classes in test code using annotation
• a0236ac: 8381406: [lworld] Reduce usage of array mark word tricks for C++ code
• 897f6db: 8379148: [lworld] Wrapper class caches should not be used when --enable-preview

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[mlbridge]

Webrevs

• 00: Full (4447566e)

[stefank]

Looks good to me. The test functions could stay non-public, I think.

[fparain]

LGTM.
Thank you for fixing this test.