8256670: Zero: enable compressed oops support back

[shipilev]

UseCompressedOops was disabled for C++ interpreter by JDK-6909153, and it eventually morphed to disabled UseCompressedOops for all Zero configurations. I see nothing that actually prevents Zero from using compressed oops: all local/stack operands are always unpacked (like they are in non-interpreted modes), all heap accesses are calling into utility methods that handle compressed oops, there are no raw accesses to oops anywhere.

Additional testing:

• Ad-hoc benchmark tests
• hotspot_gc_shenandoah with Zero, now passing compressed oops tests

---

Progress

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Testing

	Linux aarch64	Linux arm	Linux ppc64le	Linux s390x	Linux x64	Linux x86	Windows x64	macOS x64
Build	✔️ (1/1 passed)	✔️ (1/1 passed)	✔️ (1/1 passed)	✔️ (1/1 passed)	✔️ (6/6 passed)	✔️ (2/2 passed)	✔️ (2/2 passed)	✔️ (2/2 passed)
Test (tier1)					✔️ (9/9 passed)	✔️ (9/9 passed)	✔️ (9/9 passed)	✔️ (9/9 passed)

Issue

• JDK-8256670: Zero: enable compressed oops support back

Reviewers

• Coleen Phillimore (@coleenp - Reviewer)

Download

$ git fetch https://git.openjdk.java.net/jdk pull/1320/head:pull/1320
$ git checkout pull/1320

[bridgekeeper]

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[openjdk]

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

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[mlbridge]

Webrevs

• 00: Full (d070c27)

[coleenp]

Seems okay to me. I can't think of why zero disabled compressed oops.

[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:

8256670: Zero: enable compressed oops support back

Reviewed-by: coleenp

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 7 new commits pushed to the master branch:

• b9db002: 8256682: JDK-8202343 is incomplete
• b8244b6: 8236926: Concurrently uncommit memory in G1
• defdd12: 8142984: Zero: fast accessors should handle both getters and setters
• 1718aba: 8227400: Adjust jib profiles to make 3rd party tools for creating installers available on Mach5 test machines
• 9bb8223: 8253299: Manifest bytes are read twice when verifying a signed JAR
• 580f22c: 8256581: Refactor vector conversion tests
• 675d1d5: 8256516: Simplify clearing References

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.

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[shipilev]

This patch survived more rounds of testing, including quite aggressive Shenandoah tests, so it should be good.

/integrate

[openjdk]

@shipilev Since your change was applied there have been 49 commits pushed to the master branch:

• d46f6f5: 8256523: Streamline Java SHA2 implementation
• 1aa90ac: 8256822: runtime/logging/RedefineClasses.java fails with "Error: VM option 'Verbose' is develop and is available only in debug version of VM."
• edf72f0: 8256824: test/langtools/tools/javac/diags/examples/InnerClassCantHaveStatic.java has a bad copyright
• 9a19eb6: 8254105: allow static nested declarations
• 14de791: 8255934: JConsole 14 and greater fails to connect to older JVM
• 86f3602: 8256806: Shenandoah: optimize shenandoah/jni/TestPinnedGarbage.java test
• 57025e6: 8256073: Improve vector rematerialization support
• 41c0587: 8255367: C2: Deoptimization during vector box construction is broken
• f79e9d4: 8256061: RegisterSaver::save_live_registers() omits upper halves of ZMM0-15 registers
• 503590f: 8256056: Deoptimization stub doesn't save vector registers on x86
• ... and 39 more: https://git.openjdk.java.net/jdk/compare/ba721f5f2fbbf08e22a9993dce0087f46b1f5552...master

Your commit was automatically rebased without conflicts.

Pushed as commit 037e49c.

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