8340524: Remove NarrowPtrStruct

[kimbarrett]

Please review this change which removes the class NarrowPtrStruct. The only
place it was still being used was as the type of CompressedOops::_narrow_oops.
Instead, we move the members from NarrowPtrStruct directly into
CompressedOops, flattening its structure.

Testing: mach5 tier1-3
Tiers 2&3 run serviceability tests that hit the changes to that component.

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8340524: Remove NarrowPtrStruct (Enhancement - P4)

Reviewers

• Aleksey Shipilev (@shipilev - Reviewer)
• Julian Waters (@TheShermanTanker - Committer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/21115/head:pull/21115
$ git checkout pull/21115

Update a local copy of the PR:
$ git checkout pull/21115
$ git pull https://git.openjdk.org/jdk.git pull/21115/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 21115

View PR using the GUI difftool:
$ git pr show -t 21115

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/21115.diff

Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back kbarrett! 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]

@kimbarrett 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:

8340524: Remove NarrowPtrStruct

Reviewed-by: shade, jwaters

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:

• ab06a87: 8340544: Optimize setLocalsFromArg
• 2461263: 8339217: Optimize ClassFile API loadConstant
• 08b2561: 8339781: Better use of Javadoc tags in javax.lang.model
• 64275e6: 8340092: [Linux] containers/systemd/SystemdMemoryAwarenessTest.java failing on some systems
• 5cffddc: 8338471: Assert deleted methods not returned by CallInfo
• 40fba14: 8340232: Optimize DataInputStream::readUTF
• ab81197: 8339198: Remove tag field from AbstractPoolEntry
• 90d3a64: 8340537: Typo in javadoc of java.util.jar.JarFile
• e087ede: 8340269: [s390x] TestLargeStub.java failure after 8338123
• 9bcde4f: 8338658: New Object to ObjectMonitor mapping: s390x implementation
• ... and 5 more: https://git.openjdk.org/jdk/compare/5d611c0377d4b5d5495d3941a6a63b128142a2dc...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]

@kimbarrett The following labels will be automatically applied to this pull request:

• hotspot
• serviceability

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

[mlbridge]

Webrevs

• 00: Full (b9c8514c)

[shipilev]

Agreed, good cleanup.

[TheShermanTanker]

Not an objection, just a complaint on how the GitHub diff view makes this confusing to review

[TheShermanTanker]

Took me a while to work through the confusing diff in one of the files, but this looks ok

[kimbarrett]

Thanks for reviews @shipilev and @TheShermanTanker .

[kimbarrett]

/integrate

[openjdk]

Going to push as commit dd49879.
Since your change was applied there have been 15 commits pushed to the master branch:

• ab06a87: 8340544: Optimize setLocalsFromArg
• 2461263: 8339217: Optimize ClassFile API loadConstant
• 08b2561: 8339781: Better use of Javadoc tags in javax.lang.model
• 64275e6: 8340092: [Linux] containers/systemd/SystemdMemoryAwarenessTest.java failing on some systems
• 5cffddc: 8338471: Assert deleted methods not returned by CallInfo
• 40fba14: 8340232: Optimize DataInputStream::readUTF
• ab81197: 8339198: Remove tag field from AbstractPoolEntry
• 90d3a64: 8340537: Typo in javadoc of java.util.jar.JarFile
• e087ede: 8340269: [s390x] TestLargeStub.java failure after 8338123
• 9bcde4f: 8338658: New Object to ObjectMonitor mapping: s390x implementation
• ... and 5 more: https://git.openjdk.org/jdk/compare/5d611c0377d4b5d5495d3941a6a63b128142a2dc...master

Your commit was automatically rebased without conflicts.

[openjdk]

@kimbarrett Pushed as commit dd49879.

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