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8271254: javac generates unreachable code when using empty semicolon statement #5495

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@lgxbslgx lgxbslgx commented Sep 13, 2021

Hi all,

The method Gen#genTry is used by visitTry and visitSynchronized, but genTry can't identify who is invoking it so that it can't solve the concrete issues about try statement or synchronized statement separately. This patch adds a new parameter actualTry to identify the concrete situation( try or synchronized) and fixes this issue about using empty skip statement in the try statement body. And some related test cases are added.

Thanks for taking the time to review.

Best Regards,
-- Guoxiong


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  • JDK-8271254: javac generates unreachable code when using empty semicolon statement

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Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk pull/5495/head:pull/5495
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Update a local copy of the PR:
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$ git pull https://git.openjdk.java.net/jdk pull/5495/head

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https://git.openjdk.java.net/jdk/pull/5495.diff

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@bridgekeeper bridgekeeper bot commented Sep 13, 2021

👋 Welcome back gli! 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 label Sep 13, 2021
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@lgxbslgx The following label will be automatically applied to this pull request:

  • 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 compiler label Sep 13, 2021
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@mlbridge mlbridge bot commented Sep 13, 2021

Webrevs

*/
void genTry(JCTree body, List<JCCatch> catchers, Env<GenContext> env) {
void genTry(JCTree body, List<JCCatch> catchers, Env<GenContext> env, boolean actualTry) {
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@vicente-romero-oracle vicente-romero-oracle Sep 13, 2021

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I don't think you really need an additional argument, I think that you can check for the tree at the env argument and you should be able to find out if this method is being invoked from a try or not. Kind of:

boolean actualTry = env.tree.hasTag(TRY);

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@lgxbslgx lgxbslgx Sep 14, 2021

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@vicente-romero-oracle you are right. I updated the code just now by using the env instead of the new parameter.

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@vicente-romero-oracle vicente-romero-oracle left a comment

looks good

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@openjdk openjdk bot commented Sep 14, 2021

@lgxbslgx 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:

8271254: javac generates unreachable code when using empty semicolon statement

Reviewed-by: vromero

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 26 new commits pushed to the master branch:

  • 8974b95: 8273730: WorkGangBarrierSync constructor unused
  • 1d3eb14: 8273635: Attempting to acquire lock StackWatermark_lock/9 out of order with lock tty_lock/3
  • 31667da: 8273491: java.util.spi.LocaleServiceProvider spec contains statement that is too strict
  • ed7789d: 8256977: Bump minimum GCC from 5.x to 6 for JDK
  • 5bfd043: 8273497: building.md should link to both md and html
  • 3884580: 8273597: Rectify Thread::is_ConcurrentGC_thread()
  • f527289: 8273639: tests fail with "assert(_handle_mark_nesting > 1) failed: memory leak: allocating handle outside HandleMark"
  • 1d2458d: 8266550: C2: mirror TypeOopPtr/TypeInstPtr/TypeAryPtr with TypeKlassPtr/TypeInstKlassPtr/TypeAryKlassPtr
  • a143372: 8273438: Enable parallelism in vmTestbase/metaspace/stressHierarchy tests
  • 86a8e55: 8273486: Zero: Handle DiagnoseSyncOnValueBasedClasses VM option
  • ... and 16 more: https://git.openjdk.java.net/jdk/compare/f189dff5cbd4d47e1b2f3c0e5f2c866a7effccdf...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 label Sep 14, 2021
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@lgxbslgx lgxbslgx commented Sep 14, 2021

@vicente-romero-oracle Thanks for your review.

/integrate

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@openjdk openjdk bot commented Sep 14, 2021

Going to push as commit fe89dd3.
Since your change was applied there have been 26 commits pushed to the master branch:

  • 8974b95: 8273730: WorkGangBarrierSync constructor unused
  • 1d3eb14: 8273635: Attempting to acquire lock StackWatermark_lock/9 out of order with lock tty_lock/3
  • 31667da: 8273491: java.util.spi.LocaleServiceProvider spec contains statement that is too strict
  • ed7789d: 8256977: Bump minimum GCC from 5.x to 6 for JDK
  • 5bfd043: 8273497: building.md should link to both md and html
  • 3884580: 8273597: Rectify Thread::is_ConcurrentGC_thread()
  • f527289: 8273639: tests fail with "assert(_handle_mark_nesting > 1) failed: memory leak: allocating handle outside HandleMark"
  • 1d2458d: 8266550: C2: mirror TypeOopPtr/TypeInstPtr/TypeAryPtr with TypeKlassPtr/TypeInstKlassPtr/TypeAryKlassPtr
  • a143372: 8273438: Enable parallelism in vmTestbase/metaspace/stressHierarchy tests
  • 86a8e55: 8273486: Zero: Handle DiagnoseSyncOnValueBasedClasses VM option
  • ... and 16 more: https://git.openjdk.java.net/jdk/compare/f189dff5cbd4d47e1b2f3c0e5f2c866a7effccdf...master

Your commit was automatically rebased without conflicts.

@openjdk openjdk bot closed this Sep 14, 2021
@openjdk openjdk bot added integrated and removed ready rfr labels Sep 14, 2021
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@openjdk openjdk bot commented Sep 14, 2021

@lgxbslgx Pushed as commit fe89dd3.

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

@lgxbslgx lgxbslgx deleted the JDK-8271254 branch Sep 14, 2021
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