8363846: [lworld] Make Class.isIdentityClass() non-native

[coleenp]

This moves isIdentityClass() implementation to Class.java, and checks within the JVM that is_identity_class() doesn't check the access flags for an ArrayKlass, since AccessFlags aren't initialized in ArrayKlasses. The AccessFlags should be moved from Klass.hpp to InstanceKlass.cpp in mainline but that's a more complicated change and has several pieces.
Added a test.
Tested with tier1 locally.

---

Progress

• Change must not contain extraneous whitespace

Issue

• JDK-8363846: [lworld] Make Class.isIdentityClass() non-native (Enhancement - P4)

Reviewers

• Chen Liang (@liach - Committer)
• Roger Riggs (@RogerRiggs - Committer)

Reviewing

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[openjdk]

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

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

8363846: [lworld] Make Class.isIdentityClass() non-native

Reviewed-by: liach, rriggs

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

• 3626f88: 8361307: [lworld] Clarify identity vs value in Class, Objects, and document limitations of value objects
• 1fdd381: 8363956: [lworld] Valhalla vauetypes tests enablePreview should be per test
• d1c3062: 8349110: [lworld] Intrinsics for Unsafe.get/putFlatValue

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Webrevs

• 06: Full - Incremental (16210aa3)
• 05: Full - Incremental (50278a63)
• 04: Full - Incremental (3760602f)
• 03: Full - Incremental (18f90e4f)
• 02: Full - Incremental (f26fea89)
• 01: Full - Incremental (96dd8079)
• 00: Full (324e2c51)

[liach]

is_identity_class seems widely used in many areas, such as C2 - do we need to verify those usages?

[coleenp]

is_identity_class seems widely used in many areas, such as C2 - do we need to verify those usages?

Good question. I did check most/attempted all of these places and added the assert in klass.hpp but since AccessFlags are in klass, it is possible to copy them from an ArrayKlass to a ciKlass and fail the is_identity check for an array. The only way to make this completely safe is to move the access flags, which I started in another repo but it's got pretty hairy since Klass and InstanceKlass are used interchangeably in some of the compiler code that I don't know very well, when I think they really mean InstanceKlass.

[RogerRiggs]

For new tests we use junit.
See other tests like UseValueClassTest for imports and per test annotations.

[RogerRiggs]

The test looks good, the conditions are more complicated than is obvious because with --enable-preview new modifier bits are defined with new used.
Thanks for the updates.

[RogerRiggs]

Look good, thanks

[liach]

TEST.properties is updated; we might remove these directives.

[coleenp]

Thanks, I can't merge right now with the latest to test.

[liach]

The redundant directives in tests are fine.

[coleenp]

Thank you for all your help with this test, Roger and Chen.
/integrate

[openjdk]

Going to push as commit acfb4f0.
Since your change was applied there have been 3 commits pushed to the lworld branch:

• 3626f88: 8361307: [lworld] Clarify identity vs value in Class, Objects, and document limitations of value objects
• 1fdd381: 8363956: [lworld] Valhalla vauetypes tests enablePreview should be per test
• d1c3062: 8349110: [lworld] Intrinsics for Unsafe.get/putFlatValue

Your commit was automatically rebased without conflicts.

[openjdk]

@coleenp Pushed as commit acfb4f0.

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