8352565: Add native method implementation of Reference.get()

[chmielewskiandreas]

Hi, this is a clean backport of 56c75453cd69e80b9411b4e1794c953998406342

Testing:

Verified possible regressions using following tests on my local machine:

make run-test TEST="hotspot_gc"
make run-test TEST="hotspot/jtreg/gc"
make run-test TEST="jdk/java/lang/"
make run-test TEST="hotspot/jtreg/gc/stress"
make run-test TEST="vmTestbase_vm_gc"

The test that is part of the PR is part of tier1 gc run:

https://github.com/chmielewskiandreas/jdk25u-dev/actions/runs/22150746910/job/64044910144#step:10:838

To verify whether the patch works, I ran TestNativeReferenceGet.java (change line -XX:DisableIntrinsic=_Reference_get) from the PR on master, which actually failed ("RuntimeException("Reference enqueued")")

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8352565 needs maintainer approval

Issue

• JDK-8352565: Add native method implementation of Reference.get() (Enhancement - P4 - Rejected)

Reviewers

• Andrew John Hughes (@gnu-andrew - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk25u-dev.git pull/284/head:pull/284
$ git checkout pull/284

Update a local copy of the PR:
$ git checkout pull/284
$ git pull https://git.openjdk.org/jdk25u-dev.git pull/284/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 284

View PR using the GUI difftool:
$ git pr show -t 284

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk25u-dev/pull/284.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

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[chmielewskiandreas]

/covered

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[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

This backport pull request has now been updated with issue from the original commit.

[openjdk]

⚠️ @chmielewskiandreas This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[mlbridge]

Webrevs

• 00: Full (41b77995)

[chmielewskiandreas]

/approval request "I am proposing this clean backport. Low/medium risk due to the fact that the introduced native method is only used when Reference.get() isn´t intrinsified. The behavior isn't otherwise altered. The attached test is passing whereas it did not pass without this patch.

[openjdk]

@chmielewskiandreas
8352565: The approval request has been created successfully.

[gnu-andrew]

Patch and testing looks good.

This is listed as an enhancement but reads more like a bug fix to me. The existing get() method appears like a Java method, but in reality, this is usually being replaced by a native intrinsic. Having a native implementation which may be replaced by an intrinsic makes this clearer in the code. Similar patterns already exist in e.g. AESCrypt.java