8259350: Add some internal debugging APIs to the debug agent

[plummercj]

This PR adds some APIs that are useful when debugging the debug agent. They can be called from gdb or from other parts of the debug agent. They mostly do things like dumping internal data structures that are tedious to dump or iterate over in gdb. I developed them while working on loom and found them useful.

Note that dumpThreadList() and dumpThread() are not exported from threadControl.c because the argument types are only visible within threadControl.c.

I debated whether to bracket all these APIs with #ifdef DEBUG. In the end I decided to in order to make it clear they are only meant for debugging purposes. If you temporarily need them with a product build, you can always modify the code to include them. I could be persuaded #ifdef DEBUG though.

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Progress

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

Issue

• JDK-8259350: Add some internal debugging APIs to the debug agent

Reviewers

• Serguei Spitsyn (@sspitsyn - Reviewer)
• Alex Menkov (@alexmenkov - Reviewer)

Download

$ git fetch https://git.openjdk.java.net/jdk pull/1970/head:pull/1970
$ git checkout pull/1970

[bridgekeeper]

👋 Welcome back cjplummer! 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]

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[mlbridge]

Webrevs

• 00: Full (970454b)

[plummercj]

Ping! Still need 2 reviews.

[sspitsyn]

Chris,
It looks good to me.
Thanks,
Serguei

[openjdk]

@plummercj 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:

8259350: Add some internal debugging APIs to the debug agent

Reviewed-by: sspitsyn, amenkov

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 163 new commits pushed to the master branch:

• a6b2162: 8259278: Optimize Vector API slice and unslice operations
• da6bcf9: 8255019: Shenandoah: Split STW and concurrent mark into separate classes
• aba3431: 8258956: Memory Leak in StringCoding on ThreadLocal resultCached StringCoding.Result
• 8554fe6: 8253866: Security Libs Terminology Refresh
• c2a3c7e: 8259727: Remove redundant "target" arguments to methods in Links
• 1620664: 8259723: Move Table class to formats.html package
• 38a1201: 8258912: Remove JVM options CountJNICalls and CountJVMCalls
• be57cf1: 8226416: MonitorUsedDeflationThreshold can cause repeated async deflation requests
• c822eda: 8259699: Reduce char[] copying in URLEncoder.encode(String, Charset)
• ff3e6e4: 8259773: Incorrect encoding of AVX-512 kmovq instruction
• ... and 153 more: https://git.openjdk.java.net/jdk/compare/28e1f4d9eebd148c4a7e5c83a5141e8acc7ccced...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.

[plummercj]

/integrate

[openjdk]

@plummercj Since your change was applied there have been 163 commits pushed to the master branch:

• a6b2162: 8259278: Optimize Vector API slice and unslice operations
• da6bcf9: 8255019: Shenandoah: Split STW and concurrent mark into separate classes
• aba3431: 8258956: Memory Leak in StringCoding on ThreadLocal resultCached StringCoding.Result
• 8554fe6: 8253866: Security Libs Terminology Refresh
• c2a3c7e: 8259727: Remove redundant "target" arguments to methods in Links
• 1620664: 8259723: Move Table class to formats.html package
• 38a1201: 8258912: Remove JVM options CountJNICalls and CountJVMCalls
• be57cf1: 8226416: MonitorUsedDeflationThreshold can cause repeated async deflation requests
• c822eda: 8259699: Reduce char[] copying in URLEncoder.encode(String, Charset)
• ff3e6e4: 8259773: Incorrect encoding of AVX-512 kmovq instruction
• ... and 153 more: https://git.openjdk.java.net/jdk/compare/28e1f4d9eebd148c4a7e5c83a5141e8acc7ccced...master

Your commit was automatically rebased without conflicts.

Pushed as commit d18d26e.

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