8292713: Unsafe.allocateInstance should be intrinsified without UseUnalignedAccesses

[shipilev]

Clean backport to improve ARM32 performance in 17u.

---

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Issue

• JDK-8292713: Unsafe.allocateInstance should be intrinsified without UseUnalignedAccesses

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Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk17u-dev.git pull/1389/head:pull/1389
$ git checkout pull/1389

Update a local copy of the PR:
$ git checkout pull/1389
$ git pull https://git.openjdk.org/jdk17u-dev.git pull/1389/head

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$ git pr checkout 1389

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https://git.openjdk.org/jdk17u-dev/pull/1389.diff

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[bridgekeeper]

👋 Welcome back shade! 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]

This backport pull request has now been updated with issue from the original commit.

[openjdk]

@shipilev 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:

8292713: Unsafe.allocateInstance should be intrinsified without UseUnalignedAccesses

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 5 new commits pushed to the master branch:

• 17b3640: 8268582: javadoc throws NPE with --ignore-source-errors option
• 39a6b55: 8287854: Dangling reference in ClassVerifier::verify_class
• 9cb0120: 8275233: Incorrect line number reported in exception stack trace thrown from a lambda expression
• 32fda32: 8296343: CPVE thrown on missing content-length in OCSP response
• 6b362e4: 8261495: Shenandoah: reconsider update references memory ordering

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
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.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[mlbridge]

Webrevs

• 00: Full (c83b53c5)

[shipilev]

Testing is clean. Push approval is here.

/integrate

[openjdk]

Going to push as commit 0d2cc35.
Since your change was applied there have been 31 commits pushed to the master branch:

• 5bf1b9a: 8283520: JFR: Memory leak in dcmd_arena
• c581886: 8307128: Open source some drag and drop tests 4
• 14779b1: 8294717: (bf) DirectByteBuffer constructor will leak if allocating Deallocator or Cleaner fails with OOME
• 57d0a7f: 8300939: sun/security/provider/certpath/OCSP/OCSPNoContentLength.java fails due to network errors
• 436d96f: 8275287: Relax memory ordering constraints on updating instance class and array class counters
• 50aabaa: 8307347: serviceability/sa/ClhsdbDumpclass.java could leave files owned by root on macOS
• 861fe74: 8274615: Support relaxed atomic add for linux-aarch64
• fe17568: 8307135: java/awt/dnd/NotReallySerializableTest/NotReallySerializableTest.java failed
• 464a32b: 8227060: Optimize safepoint cleanup subtask order
• 6033871: 8306640: Open source several AWT TextArea related tests
• ... and 21 more: https://git.openjdk.org/jdk17u-dev/compare/879f4c591b82494157f3013041695a4cc4f1996b...master

Your commit was automatically rebased without conflicts.

[openjdk]

@shipilev Pushed as commit 0d2cc35.

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