8316694: Implement relocation of nmethod within CodeCache

[chadrako]

This PR introduces a new function to replace nmethods, addressing JDK-8316694. It enables the creation of new nmethods from existing ones, allowing method relocation in the code heap and supporting JDK-8328186.

When an nmethod is replaced, a deep copy is performed. The corresponding Java method is updated to reference the new nmethod, while the old one is marked as unused. The garbage collector handles final cleanup and deallocation.

This does not modify existing code paths and therefore does not benefit much from existing tests. New tests were created to test the new functionality

Additional Testing:

• Linux x64 fastdebug tier 1/2/3/4
• Linux aarch64 fastdebug tier 1/2/3/4

---

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-8316694: Implement relocation of nmethod within CodeCache (Enhancement - P4)

Reviewers

• Vladimir Kozlov (@vnkozlov - Reviewer)
• Erik Österlund (@fisk - Reviewer) Review applies to 3344a72a
• Tom Rodriguez (@tkrodriguez - Reviewer) Review applies to 66d73c16
• Evgeny Astigeevich (@eastig - Committer) Review applies to bf18a4c8
• Boris Ulasevich (@bulasevich - Committer) Review applies to d4e3dd31

Reviewing

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Checkout this PR locally:
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$ git checkout pull/23573

Update a local copy of the PR:
$ git checkout pull/23573
$ git pull https://git.openjdk.org/jdk.git pull/23573/head

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$ git pr checkout 23573

View PR using the GUI difftool:
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https://git.openjdk.org/jdk/pull/23573.diff

Using Webrev

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[bridgekeeper]

👋 Welcome back chadrako! 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]

@chadrako 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:

8316694: Implement relocation of nmethod within CodeCache

Reviewed-by: kvn, eosterlund, never, eastigeevich, bulasevich

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 2 new commits pushed to the master branch:

• e6868c6: 8369138: New test compiler/loopstripmining/MissingStoreAfterOuterStripMinedLoop.java fails
• 837f634: 8369128: ProblemList jdk/jfr/event/profiling/TestCPUTimeSampleQueueAutoSizes.java in Xcomp configs

Please see this link for an up-to-date comparison between the source branch of this pull request and the master 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.

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➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

[openjdk]

@chadrako The following label will be automatically applied to this pull request:

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[eastig]

lgtm

[vnkozlov]

@vnkozlov Can you take a look at the change when you have a chance. Thanks :)

I will look on it this week and do new testing.

[vnkozlov]

Update looks good. I submitted new testing.

[vnkozlov]

My testing for v46 passed.

[chadrako]

@vnkozlov There was a minor merge conflict due to JDK-8366461 if you could re-review (hopefully for the last time)

[vnkozlov]

Re-approved.

[chadrako]

/integrate

[openjdk]

@chadrako
Your change (at version 104661c) is now ready to be sponsored by a Committer.

[eastig]

/sponsor

[openjdk]

Going to push as commit f740cd2.
Since your change was applied there have been 4 commits pushed to the master branch:

• 76dba20: 8368821: Test java/net/httpclient/http3/GetHTTP3Test.java intermittently fails with java.io.IOException: QUIC endpoint closed
• c3fbbfa: 8369027: Apply java.io.Serial annotations in java.scripting
• e6868c6: 8369138: New test compiler/loopstripmining/MissingStoreAfterOuterStripMinedLoop.java fails
• ... and 1 more: https://git.openjdk.org/jdk/compare/012e079d11b629ddda8d5f687fd43ef21d210466...master

Your commit was automatically rebased without conflicts.

[openjdk]

@eastig @chadrako Pushed as commit f740cd2.

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

[vnkozlov]

@chadrako we hit failures in tier 3 testing. I will file bug.

[vnkozlov]

https://bugs.openjdk.org/browse/JDK-8369147

[vnkozlov]

https://bugs.openjdk.org/browse/JDK-8369148

[vnkozlov]

https://bugs.openjdk.org/browse/JDK-8369149
https://bugs.openjdk.org/browse/JDK-8369150

[vnkozlov]

Looks like when I tested changes I did not include new tests (forgot git add for them)

[vnkozlov]

https://bugs.openjdk.org/browse/JDK-8369151

[vnkozlov]

I problem listing new tests which fail: #27634

[TheRealMDoerr]

We also see assertions on PPC64 in the new test DeoptimizeRelocatedNMethod:

#  Internal Error (jdk/src/hotspot/cpu/ppc/nativeInst_ppc.cpp:405)
#  assert(!decode(i1, i2)) failed: already patched

Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V  [libjvm.so+0x1701784]  NativePostCallNop::patch(int, int)+0xf4  (nativeInst_ppc.cpp:405)
V  [libjvm.so+0x1718414]  nmethod::finalize_relocations()+0x6f4  (nmethod.cpp:2059)
V  [libjvm.so+0x171891c]  nmethod::post_init()+0x5c  (nmethod.cpp:1252)
V  [libjvm.so+0x171a8dc]  nmethod::relocate(CodeBlobType)+0x1ec  (nmethod.cpp:1515)
V  [libjvm.so+0x200b598]  WB_RelocateNMethodFromMethod+0x388  (whitebox.cpp:1653)
j  jdk.test.whitebox.WhiteBox.relocateNMethodFromMethod0(Ljava/lang/reflect/Executable;I)V+0
j  jdk.test.whitebox.WhiteBox.relocateNMethodFromMethod(Ljava/lang/reflect/Executable;I)V+8
j  compiler.whitebox.DeoptimizeRelocatedNMethod.main([Ljava/lang/String;)V+50

@reinrich: I assume this assertion is no longer valid.

[reinrich]

We also see assertions on PPC64 in the new test DeoptimizeRelocatedNMethod:

#  Internal Error (jdk/src/hotspot/cpu/ppc/nativeInst_ppc.cpp:405)
#  assert(!decode(i1, i2)) failed: already patched

Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V  [libjvm.so+0x1701784]  NativePostCallNop::patch(int, int)+0xf4  (nativeInst_ppc.cpp:405)
V  [libjvm.so+0x1718414]  nmethod::finalize_relocations()+0x6f4  (nmethod.cpp:2059)
V  [libjvm.so+0x171891c]  nmethod::post_init()+0x5c  (nmethod.cpp:1252)
V  [libjvm.so+0x171a8dc]  nmethod::relocate(CodeBlobType)+0x1ec  (nmethod.cpp:1515)
V  [libjvm.so+0x200b598]  WB_RelocateNMethodFromMethod+0x388  (whitebox.cpp:1653)
j  jdk.test.whitebox.WhiteBox.relocateNMethodFromMethod0(Ljava/lang/reflect/Executable;I)V+0
j  jdk.test.whitebox.WhiteBox.relocateNMethodFromMethod(Ljava/lang/reflect/Executable;I)V+8
j  compiler.whitebox.DeoptimizeRelocatedNMethod.main([Ljava/lang/String;)V+50

@reinrich: I assume this assertion is no longer valid.

Yeah, I reckon it needs to be adapted/removed. Would be nice, though, if we could keep it.