8364483: [lworld] Pre-register migrated classes in class loaders

[coleenp]

This change preloads and preregisters all classes in the migrated classes lists, in all class loaders.
Tested with tier1 locally and with -XX:+PrintSystemDictionaryAtExit.

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Progress

• Change must not contain extraneous whitespace

Issue

• JDK-8364483: [lworld] Pre-register migrated classes in class loaders (Enhancement - P4)

Reviewers

• Dan Heidinga (@DanHeidinga - no project role)

Reviewing

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[coleenp]

This is unrelated but needed to get the product build to build.

[bridgekeeper]

👋 Welcome back coleenp! A progress list of the required criteria for merging this PR into lworld will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@coleenp 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:

8364483: [lworld] Pre-register migrated classes in class loaders

Reviewed-by: heidinga

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 3 new commits pushed to the lworld branch:

• 4ce51bf: [lworld] Remove redundant DTraceAlloc/Method probes
• 67e6bcc: 8360653: [lworld] LayoutIterationTest.java fails with -XX:ForceNonTearable=*
• 4f9deef: 8364321: Add JDI tests for value objects

Please see this link for an up-to-date comparison between the source branch of this pull request and the lworld branch.
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 lworld branch, type /integrate in a new comment.

[mlbridge]

Webrevs

• 02: Full - Incremental (5ac3cac5)
• 01: Full - Incremental (1b85463c)
• 00: Full (0fd70f7e)

[fparain]

Commented line to be removed?

[coleenp]

I don't love having to enumerate all the classes in more than one place, but I also don't want to add another X macro.

[DanHeidinga]

Should this assert(i == _migrated_class_names_length); as a handshake with the size of the set of migrated classes declared in vmSymbols.hpp?

[coleenp]

That's a good idea. I didn't know a better C++ way to initialize these. I'm sure it exists.

[coleenp]

Thanks again, Dan.
/integrate

[openjdk]

Going to push as commit ed21796.
Since your change was applied there have been 3 commits pushed to the lworld branch:

• 4ce51bf: [lworld] Remove redundant DTraceAlloc/Method probes
• 67e6bcc: 8360653: [lworld] LayoutIterationTest.java fails with -XX:ForceNonTearable=*
• 4f9deef: 8364321: Add JDI tests for value objects

Your commit was automatically rebased without conflicts.

[openjdk]

@coleenp Pushed as commit ed21796.

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

[RogerRiggs]

The official list of migrated classes is in make/modules/java.base/gensrc/GensrcValueClasses.gmk.
How are all these copies of the list of files kept in sync?

[DanHeidinga]

The official list of migrated classes is in make/modules/java.base/gensrc/GensrcValueClasses.gmk.
How are all these copies of the list of files kept in sync?

This is a temporary measure to make up for classfiles that don't have a LoadedDescriptors attribute yet. Those classes - in user class loaders - won't "know" at link time that the box classes have migrated to be values and therefore won't benefit from the calling convention optimizations. This PR lets us make those classloaders aware of the changed nature of the boxing classes early and ensures they get the benefits of Valhalla. The other migrated classes are included because "why not" and so keeping the lists in sync isn't a priority.