8274401: C2: GraphKit::load_array_element bypasses Access API

[TheRealMDoerr]

C2: GraphKit::load_array_element only creates nodes for loading a raw element from the given array. This is wrong when the element is an Oop which needs a load barrier for some GCs.

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Progress

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Issue

• JDK-8274401: C2: GraphKit::load_array_element bypasses Access API

Reviewers

• Vladimir Kozlov (@vnkozlov - Reviewer)
• Goetz Lindenmaier (@GoeLin - Reviewer)
• Tobias Hartmann (@TobiHartmann - Reviewer)

Reviewing

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[openjdk]

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[mlbridge]

Webrevs

• 00: Full (cff80206)

[vnkozlov]

Changes seems fine.
Do you have a test case which shows the issue?

[TheRealMDoerr]

The only place where we currently have a real bug is LibraryCallKit::get_key_start_from_aescrypt_object on PPC64 and s390 with ZGC or ShenandoahGC. Note that these GCs are not yet contributed. But we can reproduce the problem on PPC64 with our experimental GC implementation.
So, this fix is needed to support these GCs on these platforms. And it will be needed if anyone else starts using the function for Oops.

[GoeLin]

Hi Martin,
did one of the jtreg tests fail? Maybe you could share which it was.
Maybe a @bug 8274401 in that test would be useful.
The change looks good to me.
Best regards,
Goetz.

[TheRealMDoerr]

We found the issue by running jvm2008 crypto.aes with our experimental ZGC on PPC64 with FullGCALot.
I verified the fix by disassembling C2 compiled com.sun.crypto.provider.CipherBlockChaining::implEncrypt on PPC64. The load barrier for the sessionK[0] before the implEncryptBlock intrinsic stub call is missing without this fix and gets generated with this fix.

[GoeLin]

Thanks for the explanation.
LGTM

[openjdk]

@TheRealMDoerr 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:

8274401: C2: GraphKit::load_array_element bypasses Access API

Reviewed-by: kvn, goetz, thartmann

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 35 new commits pushed to the master branch:

• 355356c: 8273435: Remove redundant zero-length check in ClassDesc.of
• 97385d4: 8274405: Suppress warnings on non-serializable non-transient instance fields in javac and javadoc
• 79cebe2: 8274050: Unnecessary Vector usage in javax.crypto
• 97b2874: 8274509: Remove stray * and stylistic . from doc comments
• b1b6696: 8274453: (sctp) com/sun/nio/sctp/SctpChannel/CloseDescriptors.java test should be resilient to lsof warnings
• edd9d1c: 8274330: Incorrect encoding of the DistributionPointName object in IssuingDistributionPointExtension
• 980c50d: 8272562: C2: assert(false) failed: Bad graph detected in build_loop_late
• 1dc8fa9: 8274340: [BACKOUT] JDK-8271880: Tighten condition for excluding regions from collecting cards with cross-references
• aaa36cc: 8274242: Implement fast-path for ASCII-compatible CharsetEncoders on x86
• c4d1157: 8271855: [TESTBUG] Wrong weakCompareAndSet assumption in UnsafeIntrinsicsTest
• ... and 25 more: https://git.openjdk.java.net/jdk/compare/c4b52c7378183ab0fb987cc571c1debea450e125...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.

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

[vnkozlov]

Okay

[TobiHartmann]

Looks good.

[TheRealMDoerr]

Thanks for the reviews!
/integrate

[openjdk]

Going to push as commit a8210c5.
Since your change was applied there have been 38 commits pushed to the master branch:

• dfc557c: 8274406: RunThese30M.java failed "assert(!LCA_orig->dominates(pred_block) || early->dominates(pred_block)) failed: early is high enough"
• c0533ef: 8274522: java/lang/management/ManagementFactory/MXBeanException.java test fails with Shenandoah
• f8415a9: 8274523: java/lang/management/MemoryMXBean/MemoryTest.java test should handle Shenandoah
• 355356c: 8273435: Remove redundant zero-length check in ClassDesc.of
• 97385d4: 8274405: Suppress warnings on non-serializable non-transient instance fields in javac and javadoc
• 79cebe2: 8274050: Unnecessary Vector usage in javax.crypto
• 97b2874: 8274509: Remove stray * and stylistic . from doc comments
• b1b6696: 8274453: (sctp) com/sun/nio/sctp/SctpChannel/CloseDescriptors.java test should be resilient to lsof warnings
• edd9d1c: 8274330: Incorrect encoding of the DistributionPointName object in IssuingDistributionPointExtension
• 980c50d: 8272562: C2: assert(false) failed: Bad graph detected in build_loop_late
• ... and 28 more: https://git.openjdk.java.net/jdk/compare/c4b52c7378183ab0fb987cc571c1debea450e125...master

Your commit was automatically rebased without conflicts.

[openjdk]

@TheRealMDoerr Pushed as commit a8210c5.

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