8364042: UnsafeMemoryAccess will not work with AOT cached code stubs

[adinn]

Array copy stubs may legitimately generate SEGV errors during copying. They rely on class UnsafeMemoryAccess to record and expose to the signal handler a table of address ranges within which a SEGV should be dealt with by redirecting execution to an associated handler address. The handler address may lie within the same stub or may default to an independent entry belonging to a specific, non-copy stub within the same blob. Normally entries are added to the table as a side-effect of generating the stub.

This patch implements the preliminary steps needed to enable save and restore of the UnsafeMemoryAccess table entries alongside with their associated AOT compiled copy stubs. It adds the common entry to the entry declarations list so it can be saved to the AOT cache during the assembly phase and reloaded, relocated and installed as the table default entry during a production run. It also implements an API that allows table entries associated with a given stub to be identified and saved during an assembly run, and retrieved, relocated and restored to the table during a production run.

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Progress

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Issue

• JDK-8364042: UnsafeMemoryAccess will not work with AOT cached code stubs (Bug - P4)

Reviewers

• Ashutosh Mehra (@ashu-mehra - Committer)
• Vladimir Kozlov (@vnkozlov - Reviewer)

Reviewing

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[bridgekeeper]

👋 Welcome back adinn! 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]

@adinn 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:

8364042: UnsafeMemoryAccess will not work with AOT cached code stubs

Reviewed-by: asmehra, kvn

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At the time when this comment was updated there had been 43 new commits pushed to the master branch:

• ea75431: 8363928: Specifying AOTCacheOutput with a blank path causes the JVM to crash
• c239c0a: 8362564: hotspot/jtreg/compiler/c2/TestLWLockingCodeGen.java fails on static JDK on x86_64 with AVX instruction extensions
• 0226c02: 8364004: Expose VMError::controlledCrash via Whitebox
• ... and 40 more: https://git.openjdk.org/jdk/compare/2f1aed2a165259a873636792cff7c9de4e1f334e...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.

[openjdk]

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[mlbridge]

Webrevs

• 01: Full - Incremental (a3b7c241)
• 00: Full (362e7e4d)

[theRealAph]

It also implements an API that allows table entries associated with a given stub to be identified and saved during an assembly run, and retrieved, relocated and restored to the table during a production run.

I guess there's no way to test this contribution because the API has no customers, but you'll submit such testing as necessary in a later PR.

[adinn]

I guess there's no way to test this contribution because the API has no customers, but you'll submit such testing as necessary in a later PR.

Yes, that's right. This will be used by a PR I am working on to save and restore stubgenerator stubs.

[ashu-mehra]

looks fine to me

[vnkozlov]

Good.

[adinn]

@vnkozlov @ashu-mehra Thanks for the reviews! Integrating now.

[adinn]

/integrate

[openjdk]

Going to push as commit a6fb87d.
Since your change was applied there have been 53 commits pushed to the master branch:

• 7af3cd9: 8156755: [TESTBUG] Fix gc/g1/humongousObjects/objectGraphTest/TestObjectGraphAfterGC.java
• 4da1c9d: 8364196: G1: Fix typo in "cset_groud_gid" local variable in G1FlushHumongousCandidateRemSets
• 302508d: 8364249: G1: Fix some comments about "maximum_collection"
• ... and 50 more: https://git.openjdk.org/jdk/compare/2f1aed2a165259a873636792cff7c9de4e1f334e...master

Your commit was automatically rebased without conflicts.

[openjdk]

@adinn Pushed as commit a6fb87d.

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