8320582: Zero: Misplaced CX8 enablement flag

[shipilev]

When doing JDK-8319777, I misplaced the _supports_cx8 = true flag setting in the method that is only called when CPU features are polled from perf counter code. We need to move the check to a proper place. JDK-8318776 would catch fire without this.

Additional testing (redoing JDK-8319777 testing):

• Linux arm Zero fastdebug now builds fine with JDK-8318776 fix
• Linux x86_32 Zero release; jcstress
• Linux x86_32 Zero fastdebug, compiler/unsafe java/lang/invoke/VarHandles
• Linux x86_32 Zero fastdebug, bootcycle-images

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Issue

• JDK-8320582: Zero: Misplaced CX8 enablement flag (Bug - P4)

Reviewers

• David Holmes (@dholmes-ora - Reviewer)

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[dholmes-ora]

It is a bit unclear exactly where the right place is in the sense that I'd expect the other variables, like _no_of_cores, to be initialized at the same time. But ok.

[openjdk]

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

8320582: Zero: Misplaced CX8 enablement flag

Reviewed-by: dholmes

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At the time when this comment was updated there had been 9 new commits pushed to the master branch:

• a4bd9e4: 8319440: RISC-V: jdk can't be built with clang due to register keyword
• 524da14: 8320418: PPC64: invokevfinal_helper duplicates code to handle ResolvedMethodEntry
• 5d4a54b: 8319449: compiler/print/CompileCommandPrintMemStat.java fails on Graal
• 35526d0: 8257076: os::scan_pages is empty on all platforms
• 25cebe8: 8317799: AIX PPC64: FFI symbol lookup doesn't find symbols
• c39d001: 8319137: release _object in ObjectMonitor dtor to avoid races
• 8b47a14: 8320309: AIX: pthreads created by foreign test library don't work as expected
• bf0a904: 8318175: AIX PPC64: Handle alignment of double in structs
• 6ce0ebb: 8295343: sun/security/pkcs11 tests fail on Linux RHEL 8.6 and newer

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

It is a bit unclear exactly where the right place is in the sense that I'd expect the other variables, like _no_of_cores, to be initialized at the same time. But ok.

Yeah. One would expect that after VM_Version::initialize is done, all these are set. Which is a proper expectation, and is what the new guarantee in JDK-8318776 apparently relies on.

Trivial? I would like to integrate as soon as testing comes back clean.

[shipilev]

Testing passes. I would like to get this in now, if we agree this is trivial.

[dholmes-ora]

Yes trivial. Sorry bad timing

[shipilev]

No problem!

/integrate

[openjdk]

Going to push as commit 06d957f.
Since your change was applied there have been 19 commits pushed to the master branch:

• 14193a0: 8314614: jdk/jshell/ImportTest.java failed with "InternalError: Failed remote listen"
• 864b39a: 8320564: RISC-V: Minimal build failed after JDK-8316592
• 2bb4b93: 8319569: Several java/util tests should be updated to accept VM flags
• 6016536: 8314745: JFR: @StackFilter
• aac4318: 8320577: Improve MessageHeader's toString() function to make HttpURLConnection's debug log readable
• 572b14a: 8320536: problemlist failing serviceability/attach/ConcAttachTest.java test on macosx
• 30462f9: 8318986: Improve GenericWaitBarrier performance
• 407cdd4: 8320207: doclet incorrectly chooses code font for a See Also link
• 1629a90: 8320331: G1 Full GC Heap verification relies on metadata not reset before verification
• 93bdc2a: 8306055: Add a built-in Catalog to JDK XML module
• ... and 9 more: https://git.openjdk.org/jdk/compare/5e818318eac8cda7d42b599dc7d7d44e5c299a9f...master

Your commit was automatically rebased without conflicts.

[openjdk]

@shipilev Pushed as commit 06d957f.

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