8293578: Duplicate ldc generated by javac

[lahodaj]

Consider code like:

var testC = "incorrect".getClass();
var testV = testC.getConstructor(String.class)
                           .newInstance("correct");
System.err.println(testV);

javac has a concept of types with attached constants (to support proper behavior of constant expressions). Normally, these constants are cleared as specific places. But, in the above case, the type of testC is actually Class<? extends String["incorrect"]>, the constant then gets propagated, and eventually the type of testV is String["incorrect"], and the code generator will then replace reads from testV with a ldc for the constant, so the code above prints "incorrect" instead of "correct".

The solution is to invoke .baseType() to remove the constant value when constructing the synthetic .getClass()'s type (so the type of testC is Class<? extends String>), and also a tweak to checkLocalVarType, as suggested in the bug.

---

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Issue

• JDK-8293578: Duplicate ldc generated by javac

Reviewers

• Maurizio Cimadamore (@mcimadamore - Reviewer)

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[mlbridge]

Webrevs

• 00: Full (881fa67e)

[mcimadamore]

Looks good

[mcimadamore]

watch out for newline

[openjdk]

@lahodaj 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:

8293578: Duplicate ldc generated by javac

Reviewed-by: mcimadamore

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 15 new commits pushed to the master branch:

• ecb456a: 8293779: redundant checking in AESCrypt.makeSessionKey() method
• 6fca9ae: 8288474: Move EventContinuationFreezeOld from try_freeze_fast to freeze_slow
• fbd8b42: 8293591: Remove use of Thread.stop from jshell tests
• aff5ff1: 8244681: Add a warning for possibly lossy conversion in compound assignments
• 15cb1fb: 8256265: G1: Improve parallelism in regions that failed evacuation
• b31a03c: 8293695: Implement isInfinite intrinsic for RISC-V
• 8f3bbe9: 8293472: Incorrect container resource limit detection if manual cgroup fs mounts present
• 1caba0f: 8292948: JEditorPane ignores font-size styles in external linked css-file
• eeb625e: 8290169: adlc: Improve child constraints for vector unary operations
• 2057070: 8293815: P11PSSSignature.engineUpdate should not print debug messages during normal operation
• ... and 5 more: https://git.openjdk.org/jdk/compare/7f3250d71c4866a64eb73f52140c669fe90f122f...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.

[lahodaj]

/integrate

[openjdk]

Going to push as commit 39cd163.
Since your change was applied there have been 25 commits pushed to the master branch:

• 7765942: 8290367: Update default value and extend the scope of com.sun.jndi.ldap.object.trustSerialData system property
• 11e7d53: 8293819: sun/util/logging/PlatformLoggerTest.java failed with "RuntimeException: Retrieved backing PlatformLogger level null is not the expected CONFIG"
• 141d5f5: 8293767: AWT test TestSinhalaChar.java has old SCCS markings
• 3beca2d: 8291600: [vectorapi] vector cast op check is not always needed for vector mask cast
• 9a40b76: 8293842: IPv6-only systems throws UnsupportedOperationException for several socket/TCP options
• bb9aa4e: 8293813: ProblemList com/sun/jdi/JdbLastErrorTest.java on windows-x64 in Xcomp mode
• 4cec141: 8291509: Minor cleanup could be done in sun.security
• 6beeb84: 8293875: ProblemList sun/management/jmxremote/bootstrap/RmiBootstrapTest.java#id1 on linux-x64
• bf79f99: 8292989: Avoid dynamic memory in AsyncLogWriter
• 2028ec7: 8289608: Change com/sun/jdi tests to not use Thread.suspend/resume
• ... and 15 more: https://git.openjdk.org/jdk/compare/7f3250d71c4866a64eb73f52140c669fe90f122f...master

Your commit was automatically rebased without conflicts.

[openjdk]

@lahodaj Pushed as commit 39cd163.

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