8263434: Dangling references after MethodComparator::methods_EMCP

[shipilev]

SonarCloud reports the following problem in MethodComparator::methods_EMCP:
"Address of stack memory associated with local variable 's_new' is still referred to by the global variable '_s_new' upon returning to the caller. This will be a dangling reference"

Code inspection reveals the assignment to static variables is only needed to pass them to helper methods. So, while this is not a detectable bug (yet), it is still cleaner not to expose stack variables in globals.

Additional testing:

• Linux x86_64 fastdebug tier1
• Linux x86_64 fastdebug, vmTestbase_nsk_jvmti

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change must be properly reviewed

Issue

• JDK-8263434: Dangling references after MethodComparator::methods_EMCP

Reviewers

• Coleen Phillimore (@coleenp - Reviewer) ⚠️ Review applies to 9a43dca
• Serguei Spitsyn (@sspitsyn - Reviewer)

Download

$ git fetch https://git.openjdk.java.net/jdk pull/2937/head:pull/2937
$ git checkout pull/2937

[bridgekeeper]

👋 Welcome back shade! 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]

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

• hotspot

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.

[mlbridge]

Webrevs

• 02: Full - Incremental (82bf43e)
• 01: Full - Incremental (5acc480)
• 00: Full (9a43dca)

[coleenp]

This is much cleaner! Thank you, and thank you SonarCloud.

[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:

8263434: Dangling references after MethodComparator::methods_EMCP

Reviewed-by: coleenp, sspitsyn

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 no new commits pushed to the master branch. If another commit should be pushed before you perform the /integrate command, your PR will be automatically rebased. If you prefer to avoid any potential 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.

[coleenp]

/label add serviceability-dev

[openjdk]

@coleenp
The serviceability label was successfully added.

[shipilev]

/reviewers 2

[openjdk]

@shipilev
The number of required reviews for this PR is now set to 2 (with at least 1 of role reviewers).

[dcubed-ojdk]

Please make sure that you get a review from someone on the Serviceability team.

[sspitsyn]

Aleksey,
Sorry for being late to the party.
This looks good to me.
One nit: unneeded extra '()' what came from the original code:
if ((old_cp->klass_at_noresolve(cpi_old) != new_cp->klass_at_noresolve(cpi_new)))

Thanks,
Serguei

[shipilev]

One nit: unneeded extra '()' what came from the original code:
if ((old_cp->klass_at_noresolve(cpi_old) != new_cp->klass_at_noresolve(cpi_new)))

Sure, updated. Also updated copyrights.

[shipilev]

/integrate

[openjdk]

@shipilev Since your change was applied there have been 5 commits pushed to the master branch:

• 23fc2a4: 8263688: Coordinate equals, hashCode and compareTo of JavacFileManager.PathAndContainer
• d1baed6: 8263672: fatal error: no reachable node should have no use
• 086a66a: 8261095: Add test for clhsdb "symbol" command
• ec95a5c: 8263410: ListModel javadoc refers to non-existent interface
• 7b9d256: 8261262: Kitchensink24HStress.java crashed with EXCEPTION_ACCESS_VIOLATION

Your commit was automatically rebased without conflicts.

Pushed as commit f9f2eef.

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