8269574: C2: Avoid redundant uncommon traps in GraphKit::builtin_throw() for JVMTI exception events

[reinrich]

This change moves the first uncommon trap in GraphKit::builtin_throw() to the block where it is actually needed because it has a return statement.

Other paths reach the second uncommon trap at the end of GraphKit::builtin_throw(). On these paths the first UCT is not needed.

The change improves performance if the VM can post exceptions to JVMTI agents.
E.g. I found that the change improves the score for the compiler.compiler benchmark of SPECjvm2008 by 4% if the JDWP agent is loaded (see attachment in JBS).

Note that with the change we can trap with Deoptimization::Action_maybe_recompile if we don't throw a preallocated exception where before we would have trapped with Deoptimization::Action_none if it was for posting the exception to JVMTI. I'd think this is preferable.

The fix passed our CI testing: JCK and JTREG, also in Xcomp mode, SPECjvm2008, SPECjbb2015, Renaissance Suite,
SAP specific tests with fastdebug and release builds on all platforms.

---

Progress

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Issue

• JDK-8269574: C2: Avoid redundant uncommon traps in GraphKit::builtin_throw() for JVMTI exception events

Reviewers

• Vladimir Kozlov (@vnkozlov - Reviewer)
• Roland Westrelin (@rwestrel - Reviewer)
• Nils Eliasson (@neliasso - 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]

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[mlbridge]

Webrevs

• 00: Full (7d4b39b1)

[vnkozlov]

Good. Let me run some tests before push.

[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:

8269574: C2: Avoid redundant uncommon traps in GraphKit::builtin_throw() for JVMTI exception events

Reviewed-by: kvn, roland, neliasso

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 50 new commits pushed to the master branch:

• de61328: 8225559: assertion error at TransTypes.visitApply
• 82bfc5d: 8268960: com/sun/net/httpserver/Headers.java: Ensure mutators normalize keys and disallow null for keys and values
• 18f356a: 8267307: Introduce new client property for XAWT: xawt.mwm_decor_title
• 54a9c3e: 8133873: Simplify {Register,Unregister}NMethodOopClosure
• 06d2620: 8268298: jdk/jfr/api/consumer/log/TestVerbosity.java fails: unexpected log message
• d89e630: 8266746: C1: Replace UnsafeGetRaw with UnsafeGet when setting up OSR entry block
• 4660f72: 8268870: Remove dead code in metaspaceShared
• 9def3b0: Merge
• 9ac63a6: 8262841: Clarify the behavior of PhantomReference::refersTo
• aba6c55: 8269703: ProblemList vmTestbase/nsk/jvmti/scenarios/sampling/SP07/sp07t002/TestDescription.java on Windows-X64 with -Xcomp
• ... and 40 more: https://git.openjdk.java.net/jdk/compare/a97715755d01b88ad9e4cf32f10ca5a3f2fda898...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.

[vnkozlov]

tier1-3 testing passed clean.

You need second review.

[reinrich]

tier1-3 testing passed clean.

You need second review.

Thank you for reviewing and testing. I'll wait for another review.

[rwestrel]

Looks good to me.

[reinrich]

Looks good to me.

Thanks!

[neliasso]

Looks good.

[reinrich]

Looks good.

Thanks Nils!

[reinrich]

/integrate

[openjdk]

Going to push as commit 72530ef.
Since your change was applied there have been 116 commits pushed to the master branch:

• 3d090e7: 8267625: AARCH64: typo in LIR_Assembler::emit_profile_type
• a9e2010: 8268425: Show decimal nid of OSThread instead of hex format one
• 01c29d8: 8266407: remove jdk.internal.javac.PreviewFeature.Feature.SEALED_CLASSES
• 7a4f08a: Merge
• 0d1cd3a: 8269825: [TESTBUG] Missing testing for x86 KNL platforms
• e0c130f: 8269955: ProblemList compiler/vectorapi/VectorCastShape[64|128]Test.java tests on x86
• 1166ef2: 8268966: AArch64: 'bad AD file' in some vector conversion tests
• 3a69024: 8225667: Clarify the behavior of System::gc w.r.t. reference processing
• 2b20778: 8269568: JVM crashes when running VectorMask query tests
• 0f4e07b: 8269661: JNI_GetStringCritical does not lock char array
• ... and 106 more: https://git.openjdk.java.net/jdk/compare/a97715755d01b88ad9e4cf32f10ca5a3f2fda898...master

Your commit was automatically rebased without conflicts.

[openjdk]

@reinrich Pushed as commit 72530ef.

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