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8274401: C2: GraphKit::load_array_element bypasses Access API #5727

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TheRealMDoerr
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@TheRealMDoerr TheRealMDoerr commented Sep 27, 2021

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

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@bridgekeeper bridgekeeper bot commented Sep 27, 2021

👋 Welcome back mdoerr! 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 openjdk bot added the rfr Pull request is ready for review label Sep 27, 2021
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@openjdk openjdk bot commented Sep 27, 2021

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

  • hotspot-compiler

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

@openjdk openjdk bot added the hotspot-compiler hotspot-compiler-dev@openjdk.org label Sep 27, 2021
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@mlbridge mlbridge bot commented Sep 27, 2021

Webrevs

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@vnkozlov vnkozlov left a comment

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

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@TheRealMDoerr TheRealMDoerr commented Sep 28, 2021

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.

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@GoeLin GoeLin left a comment

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.

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@TheRealMDoerr TheRealMDoerr commented Sep 29, 2021

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.

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GoeLin approved these changes Sep 29, 2021
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@GoeLin GoeLin commented Sep 29, 2021

Thanks for the explanation.
LGTM

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@openjdk openjdk bot commented Sep 29, 2021

@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.

@openjdk openjdk bot added the ready Pull request is ready to be integrated label Sep 29, 2021
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@vnkozlov vnkozlov left a comment

Okay

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@TobiHartmann TobiHartmann left a comment

Looks good.

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@TheRealMDoerr TheRealMDoerr commented Sep 30, 2021

Thanks for the reviews!
/integrate

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@openjdk openjdk bot commented Sep 30, 2021

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 openjdk bot closed this Sep 30, 2021
@openjdk openjdk bot added integrated Pull request has been integrated and removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels Sep 30, 2021
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@openjdk openjdk bot commented Sep 30, 2021

@TheRealMDoerr Pushed as commit a8210c5.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

@TheRealMDoerr TheRealMDoerr deleted the 8274401_C2_load_array_element branch Sep 30, 2021
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