8253002: Remove the unused SafePointNode::_oop_map field

[JornVernee]

Hi,

I've been looking a lot at the code for generating oop maps for call nodes lately, and noticed that SafePointNode had an oopMap field that was unused (which led to some confusion as to where the oop map was actually set).

The oop map is instead generated and set in buildOopMap OopFlow::compute_reach after matching: https://github.com/openjdk/jdk/blob/master/src/hotspot/share/opto/buildOopMap.cpp#L122 So the field on the ideal node is unused.

This patch removes the field and cleans up related code. I've left a comment in SafePointNode to point people looking for the oop map at buildOopMap.cpp

Thanks,
Jorn

Testing: local build + tier1,tier2,tier3

---

Progress

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

Issue

• JDK-8253002: Remove the unused SafePointNode::_oop_map field

Reviewers

• Tobias Hartmann (@TobiHartmann - Reviewer)

Download

$ git fetch https://git.openjdk.java.net/jdk pull/109/head:pull/109
$ git checkout pull/109

[bridgekeeper]

👋 Welcome back jvernee! 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]

@JornVernee 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 (add|remove) "label" command.

[mlbridge]

Webrevs

• 01: Full - Incremental (d636dcd)
• 00: Full (05bdc4d)

[ghost]

Hi @kasim672, thanks for making a comment in an OpenJDK project!

All comments and discussions in the OpenJDK Community must be made available under the OpenJDK Terms of Use. If you already are an OpenJDK Author, Committer or Reviewer, please click here to open a new issue so that we can record that fact. Please Use "Add GitHub user kasim672 for the summary.

If you are not an OpenJDK Author, Committer or Reviewer, simply check the box below to accept the OpenJDK Terms of Use for your comments.

• I agree to the OpenJDK Terms of Use for all comments I make in a project in the OpenJDK GitHub organization.

Your comment will be automatically restored once you have accepted the OpenJDK Terms of Use.

[shipilev]

There is also a forward declaration of class OopMap; in callnode.hpp, do we still need it?

[JornVernee]

@shipilev Thanks for the review!

There is also a forward declaration of class OopMap; in callnode.hpp, do we still need it?

Doesn't look like it, good catch!

I don't think we need this comment. I think it would bitrot eventually. It seems the code to construct OopMap is easily discoverable already.

Yeah, good point, I've removed it.

I've ran a build on Windows and Linux (WSL). Still builds with the new changes, I hope that's enough to test them.

[TobiHartmann]

Looks good.

[openjdk]

@JornVernee This change now passes all automated pre-integration checks. In addition to the automated checks, the change must also fulfill all project specific requirements

After integration, the commit message will be:

8253002: Remove the unused SafePointNode::_oop_map field

Reviewed-by: thartmann

• If you would like to add a summary, use the /summary command.
• To credit additional contributors, use the /contributor command.
• To add additional solved issues, use the /issue command.

Since the source branch of this PR was last updated there have been 38 commits pushed to the master branch:

• dafcf10: 8027545: Improve object array chunking test in G1's copy_to_survivor_space
• 7eb4d4a: 8247909: Improve PrimitiveConversions::cast using C++14
• fa30241: 8249676: [REDO] G1 incorrectly limiting young gen size when using the reserve can result in repeated full gcs
• 9ea43a9: 8253148: Fix terminology in align_down comment
• 3f455f0: 8253089: Windows (MSVC 2017) build fails after JDK-8243208
• af8c678: 8247910: Improve alignment and power-of-2 utilities using C++14
• 70cc7fc: 8253098: Archived full module graph should be disabled if CDS heap cannot be mapped
• ac9d1b0: 8223187: Remove setLocale() call in jpackage native launcher
• 9c24a56: 8253029: [PPC64] Remove obsolete Power6 code
• e6a493a: 8252882: Clean up jdk.javadoc and the related parts of jdk.compiler
• ... and 28 more: https://git.openjdk.java.net/jdk/compare/7ccf4358256a0fef895e4081f90b04f71d21bf9d...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid automatic rebasing, please merge master into your branch, and then specify the current head hash when integrating, like this: /integrate dafcf1056f5cb1772eb61fca9ee46fe24c83fc09.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[JornVernee]

/integrate

[openjdk]

@JornVernee Since your change was applied there have been 38 commits pushed to the master branch:

• dafcf10: 8027545: Improve object array chunking test in G1's copy_to_survivor_space
• 7eb4d4a: 8247909: Improve PrimitiveConversions::cast using C++14
• fa30241: 8249676: [REDO] G1 incorrectly limiting young gen size when using the reserve can result in repeated full gcs
• 9ea43a9: 8253148: Fix terminology in align_down comment
• 3f455f0: 8253089: Windows (MSVC 2017) build fails after JDK-8243208
• af8c678: 8247910: Improve alignment and power-of-2 utilities using C++14
• 70cc7fc: 8253098: Archived full module graph should be disabled if CDS heap cannot be mapped
• ac9d1b0: 8223187: Remove setLocale() call in jpackage native launcher
• 9c24a56: 8253029: [PPC64] Remove obsolete Power6 code
• e6a493a: 8252882: Clean up jdk.javadoc and the related parts of jdk.compiler
• ... and 28 more: https://git.openjdk.java.net/jdk/compare/7ccf4358256a0fef895e4081f90b04f71d21bf9d...master

Your commit was automatically rebased without conflicts.

Pushed as commit d219d8b.

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