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8282218: C1: Missing side effects of dynamic class loading during constant linkage #7612

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@iwanowww iwanowww commented Feb 24, 2022

(The problem is similar to JDK-8282194, but with class loading this time.)

C1 handles unresolved constants by performing constant resolution at runtime and then putting the constant value into the generated code by patching it. But it treats the not-yet-resolved value as a pure constant without any side effects.

It's not the case for constants which trigger class loading using custom class loaders. (All non-String constants do that.)

There are no guarantees that there are no side effects during class loading, so C1 has to be conservative.

Proposed fix kills memory after accessing not-yet-loaded constant in the context of any non-trusted class loader.

Testing: hs-tier1 - hs-tier4


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  • JDK-8282218: C1: Missing side effects of dynamic class loading during constant linkage

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Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk pull/7612/head:pull/7612
$ git checkout pull/7612

Update a local copy of the PR:
$ git checkout pull/7612
$ git pull https://git.openjdk.java.net/jdk pull/7612/head

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Checkout this PR locally:
$ git pr checkout 7612

View PR using the GUI difftool:
$ git pr show -t 7612

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Download this PR as a diff file:
https://git.openjdk.java.net/jdk/pull/7612.diff

@iwanowww iwanowww marked this pull request as ready for review February 24, 2022 13:51
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👋 Welcome back vlivanov! 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 Feb 24, 2022
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openjdk bot commented Feb 24, 2022

@iwanowww 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 Feb 24, 2022
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mlbridge bot commented Feb 24, 2022

Webrevs

cur_bc() == Bytecodes::_ldc2_w, "not supported: %s", Bytecodes::name(cur_bc()));

int index = get_constant_pool_index();
constantTag tag = get_raw_pool_tag(index);
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Looks like these lines are the same as in is_dynamic_constant(). Can you move them in separate method to avoid duplication?

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Ok, I introduced a no-arg get_raw_pool_tag() helper method. Does it look better?

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Looks good to me.

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openjdk bot commented Feb 25, 2022

@iwanowww 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:

8282218: C1: Missing side effects of dynamic class loading during constant linkage

Reviewed-by: thartmann, kvn

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 55 new commits pushed to the master branch:

  • d8f9686: 8286342: ProblemList compiler/c2/irTests/TestEnumFinalFold.java
  • bb52ea6: 8286263: compiler/c1/TestPinnedIntrinsics.java failed with "RuntimeException: testCurrentTimeMillis failed with -3"
  • 5a1d8f7: 8285295: Need better testing for IdentityHashMap
  • 080f3c5: 8286190: Add test to verify constant folding for Enum fields
  • 1277f5d: 8286154: Fix 3rd party notices in test files
  • 2dd4dfd: 8286291: G1: Remove unused segment allocator printouts
  • b9f4370: 8286189: G1: Change "wasted" memory to "unused" memory in reporting
  • c6eab98: 8285378: Remove unnecessary nop for C1 exception and deopt handler
  • 3cdedf1: 8248863: Add search landing page to API documentation
  • fa1ca98: 8281429: PhiNode::Value() is too conservative for tripcount of CountedLoop
  • ... and 45 more: https://git.openjdk.java.net/jdk/compare/efcd3d3a8fd19909ef21a07cc61613aad4dbe145...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 Feb 25, 2022
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@iwanowww This pull request has been inactive for more than 4 weeks and will be automatically closed if another 4 weeks passes without any activity. To avoid this, simply add a new comment to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

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Comment to keep this open.

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Update looks good. Thanks!

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iwanowww commented May 6, 2022

Thanks for the reviews, Vladimir & Tobias.

/integrate

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openjdk bot commented May 6, 2022

Going to push as commit 5212535.
Since your change was applied there have been 55 commits pushed to the master branch:

  • d8f9686: 8286342: ProblemList compiler/c2/irTests/TestEnumFinalFold.java
  • bb52ea6: 8286263: compiler/c1/TestPinnedIntrinsics.java failed with "RuntimeException: testCurrentTimeMillis failed with -3"
  • 5a1d8f7: 8285295: Need better testing for IdentityHashMap
  • 080f3c5: 8286190: Add test to verify constant folding for Enum fields
  • 1277f5d: 8286154: Fix 3rd party notices in test files
  • 2dd4dfd: 8286291: G1: Remove unused segment allocator printouts
  • b9f4370: 8286189: G1: Change "wasted" memory to "unused" memory in reporting
  • c6eab98: 8285378: Remove unnecessary nop for C1 exception and deopt handler
  • 3cdedf1: 8248863: Add search landing page to API documentation
  • fa1ca98: 8281429: PhiNode::Value() is too conservative for tripcount of CountedLoop
  • ... and 45 more: https://git.openjdk.java.net/jdk/compare/efcd3d3a8fd19909ef21a07cc61613aad4dbe145...master

Your commit was automatically rebased without conflicts.

@openjdk openjdk bot added the integrated Pull request has been integrated label May 6, 2022
@openjdk openjdk bot closed this May 6, 2022
@openjdk openjdk bot removed ready Pull request is ready to be integrated rfr Pull request is ready for review labels May 6, 2022
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openjdk bot commented May 6, 2022

@iwanowww Pushed as commit 5212535.

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

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