8350106: [PPC] Avoid ticks_unknown_not_Java AsyncGetCallTrace() if JavaFrameAnchor::_last_Java_pc not set

[reinrich]

This pr changes JavaThread::pd_get_top_frame_for_profiling to better address situations where

1. JavaThread::last_Java_sp() returns != null
2. JavaThread::last_Java_pc() returns null

If the runtime needs to walk the stack of a java thread in that state, e.g. for gc purposes, it finds the last java pc relative to the last java sp (see frame::setup()).

This relies on the runtime method being called to store the return pc to its caller's abi which it will do when pushing a new frame for calling another method.

For an asynchronous interrupt to sample the stack this means: if there isn't at least one frame between the last java frame and the frame where the interrupt occurred then we can't be sure that the return pc was already saved and pd_get_top_frame_for_profiling() needs to return false indicating failure.

Otherwise we can and should proceed constructing a frame even though JavaThread::last_Java_pc() returned null.

Testing:

• DaCapo Tomcat with async-profiler on a fastdebug build.
• Tier 1-4 of hotspot and jdk on the main platforms and also on Linux/PPC64le and AIX.

---

Progress

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Issue

• JDK-8350106: [PPC] Avoid ticks_unknown_not_Java AsyncGetCallTrace() if JavaFrameAnchor::_last_Java_pc not set (Bug - P4)

Reviewers

• Martin Doerr (@TheRealMDoerr - Reviewer)

Reviewing

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[bridgekeeper]

👋 Welcome back rrich! 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]

@reinrich 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:

8350106: [PPC] Avoid ticks_unknown_not_Java AsyncGetCallTrace() if JavaFrameAnchor::_last_Java_pc not set

Reviewed-by: mdoerr

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At the time when this comment was updated there had been 6 new commits pushed to the master branch:

• d90b79a: 8351046: Rename ObjectMonitor functions
• e90b6bd: 8350638: Make keyboard navigation more usable in API docs
• 4867a4c: 8351280: Mark Assertion Predicates useless instead of replacing them by a constant directly
• 64caf08: 8350572: ZGC: Enhance z_verify_safepoints_are_blocked interactions with VMError
• fb0efbe: 8333578: Fix uses of overaligned types induced by ZCACHE_ALIGNED
• 99547c5: 8346825: [JVMCI] Remove NativeImageReinitialize annotation

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[openjdk]

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

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[mlbridge]

Webrevs

• 01: Full - Incremental (0f210b81)
• 00: Full (768bfcbd)

[TheRealMDoerr]

Nice enhancement to get more samples! LGTM.

[reinrich]

Test failure on aarch64 is unrelated.
Thanks for the review Martin.
/integrate

[openjdk]

Going to push as commit 030c85d.
Since your change was applied there have been 25 commits pushed to the master branch:

• 0ad9a10: 8351146: JFR: JavaMonitorInflate event should default to no threshold and be disabled
• b957e5e: 8351322: Parameterize link option for pthreads
• af9af7e: 8351145: RISC-V: only enable some crypto intrinsic when AvoidUnalignedAccess == false
• 83de340: 8343789: Move mutable nmethod data out of CodeCache
• 0de2cdd: 8351458: (ch) Move preClose to UnixDispatcher
• cd9f1d3: 8286204: [Accessibility,macOS,VoiceOver] VoiceOver reads the spinner value 10 as 1 when user iterates to 10 for the first time on macOS
• 4cf6316: 8351414: C2: MergeStores must happen after RangeCheck smearing
• 8a5ed47: 8350148: Native stack overflow when writing Java heap objects into AOT cache
• 5928209: 8347405: MergeStores with reverse bytes order value
• f984c2b: 8351505: (fs) Typo in the documentation of java.nio.file.spi.FileSystemProvider.getFileSystem()
• ... and 15 more: https://git.openjdk.org/jdk/compare/ec683a18bcd8a8282989ba97238899d6375f43c8...master

Your commit was automatically rebased without conflicts.

[openjdk]

@reinrich Pushed as commit 030c85d.

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

[shipilev]

Apparently causes #24216, take a look?