8283626: AArch64: Set relocInfo::offset_unit to 4

[eastig]

AArch64 instructions size is 4 bytes. Two lowest bits of relocInfo offsets can be discarded.
Tested with release and fastdebug builds:

• gtest: Passed.
• tier1...tier4: Passed

---

Progress

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Issue

• JDK-8283626: AArch64: Set relocInfo::offset_unit to 4

Reviewers

• Volker Simonis (@simonis - Reviewer)
• Andrew Haley (@theRealAph - Reviewer)

Reviewing

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[bridgekeeper]

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

[openjdk]

@eastig The following label will be automatically applied to this pull request:

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[mlbridge]

Webrevs

• 01: Full - Incremental (9b040c31)
• 00: Full (1104f4e4)

[theRealAph]

Suggested change

	// AArch64 instructions size is 4 bytes.
	// Two lowest offset bits can always be discarded.
	// AArch64 instructions are always 4 bytes long and 4-aligned, so the
	// two lowest offset bits can always be discarded.

[eastig]

@theRealAph Thank you for reviewing and comments.

[theRealAph]

Looks good. I remember this being suggested a long time ago, but we were close to release and I was worried something might break unexpectedly.

[simonis]

Looks good to me.

This also fixes the issue that currently OptoLoopAlignment can be set to 1 although it should be a multiple of NOP size according to OptoLoopAlignmentConstraintFunc().

[openjdk]

@eastig 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:

8283626: AArch64: Set relocInfo::offset_unit to 4

Reviewed-by: simonis, aph

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 36 new commits pushed to the master branch:

• cc598e0: 8283774: TestZoneOffset::test_immutable should ignore ZoneOffset::rules
• 0e788e0: 8283781: Avoid allocating unused lastRulesCaches
• 043b0a7: 8273355: Flickering on tooltip appearance IntelliJ IDEA 2021.2.1
• 2367228: 8283834: Unmappable character for US-ASCII encoding in TestPredicateInputBelowLoopPredicate
• 2e9fd56: 8283670: gtest os.release_multi_mappings_vm is still racy
• f01cce2: 8264160: Regex \b is not consistent with \w without UNICODE_CHARACTER_CLASS
• 634800a: 8283806: [BACKOUT] JDK 19 L10n resource files update - msgdrop 10
• 9b49900: 8283603: Remove redundant qualifier in Windows specific Attach Operation
• d8fd222: 8282538: PKCS11 tests fail on CentOS Stream 9
• d472c01: 8283711: Remove redundant 'new String' calls after concatenation
• ... and 26 more: https://git.openjdk.java.net/jdk/compare/70648a6a153e5d321f78cf6445a9703f41083725...master

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.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@simonis, @theRealAph) but any other Committer may sponsor as well.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

[eastig]

/integrate

[openjdk]

@eastig
Your change (at version 9b040c3) is now ready to be sponsored by a Committer.

[simonis]

/sponsor

[openjdk]

Going to push as commit ab17f88.
Since your change was applied there have been 37 commits pushed to the master branch:

• c3d903a: 8282936: Write a regression test for JDK-4615365
• cc598e0: 8283774: TestZoneOffset::test_immutable should ignore ZoneOffset::rules
• 0e788e0: 8283781: Avoid allocating unused lastRulesCaches
• 043b0a7: 8273355: Flickering on tooltip appearance IntelliJ IDEA 2021.2.1
• 2367228: 8283834: Unmappable character for US-ASCII encoding in TestPredicateInputBelowLoopPredicate
• 2e9fd56: 8283670: gtest os.release_multi_mappings_vm is still racy
• f01cce2: 8264160: Regex \b is not consistent with \w without UNICODE_CHARACTER_CLASS
• 634800a: 8283806: [BACKOUT] JDK 19 L10n resource files update - msgdrop 10
• 9b49900: 8283603: Remove redundant qualifier in Windows specific Attach Operation
• d8fd222: 8282538: PKCS11 tests fail on CentOS Stream 9
• ... and 27 more: https://git.openjdk.java.net/jdk/compare/70648a6a153e5d321f78cf6445a9703f41083725...master

Your commit was automatically rebased without conflicts.

[openjdk]

@simonis @eastig Pushed as commit ab17f88.

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