8266017: Refactor the *klass::array_klass_impl code to separate the non-exception-throwing API

[dholmes-ora]

We currently have array_klass() and array_klass_or_null(), where the former can throw exceptions and the latter can not. But they both delegate to:

array_klass_impl(bool or_null, TRAPS)

which combines both the exception-throwing and non-exception-throwing code into one method declared with TRAPS. To make progress with the change of TRAPS to JavaThread (JDK-8252685) we need to separate these code paths into distinct methods.

Testing: tiers 1-3 (in progress)

Thanks,
David

---

Progress

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Issue

• JDK-8266017: Refactor the *klass::array_klass_impl code to separate the non-exception-throwing API

Reviewers

• Coleen Phillimore (@coleenp - Reviewer) ⚠️ Review applies to 80c307c
• Ioi Lam (@iklam - Reviewer)

Reviewing

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[bridgekeeper]

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[openjdk]

@dholmes-ora The following label will be automatically applied to this pull request:

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[mlbridge]

Webrevs

• 02: Full - Incremental (d7e7d5a4)
• 01: Full (80c307c0)
• 00: Full (1c2f80b1)

[dholmes-ora]

/label remove hotspot

[openjdk]

@dholmes-ora
The hotspot label was successfully removed.

[dholmes-ora]

/label add hotspot-runtime

[openjdk]

@dholmes-ora
The hotspot-runtime label was successfully added.

[mlbridge]

Mailing list message from David Holmes on hotspot-runtime-dev:

Forwarded from hotspot-dev (I didn't see the mailing list selection in
time).

David
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From: David Holmes <dholmes at openjdk.java.net>
Subject: RFR: 8266017: Refactor the *klass::array_klass_impl code to separate the non-exception-throwing API
Date: Tue, 27 Apr 2021 05:01:11 GMT
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[mlbridge]

Mailing list message from David Holmes on hotspot-runtime-dev:

Forwarded from hotspot-dev (I didn't see the mailing list selection in
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David
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From: David Holmes <dholmes at openjdk.java.net>
Subject: RFR: 8266017: Refactor the *klass::array_klass_impl code to separate the non-exception-throwing API
Date: Tue, 27 Apr 2021 05:01:11 GMT
Size: 13398
URL: <https://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/attachments/20210427/3bf4bbc0/array_klass_implcodetoseparatethenon-exception-throwingAPI.eml>

[coleenp]

This is a nice cleanup. I wish we'd done this years ago!

[openjdk]

@dholmes-ora This change now passes all automated pre-integration checks.

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After integration, the commit message for the final commit will be:

8266017: Refactor the *klass::array_klass_impl code to separate the non-exception-throwing API

Reviewed-by: coleenp, iklam

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[mlbridge]

Mailing list message from David Holmes on hotspot-runtime-dev:

On 28/04/2021 6:50 am, Ioi Lam wrote:

On Tue, 27 Apr 2021 12:46:56 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

We currently have array_klass() and array_klass_or_null(), where the former can throw exceptions and the latter can not. But they both delegate to:

array_klass_impl(bool or_null, TRAPS)

which combines both the exception-throwing and non-exception-throwing code into one method declared with TRAPS. To make progress with the change of TRAPS to JavaThread (JDK-8252685) we need to separate these code paths into distinct methods.

Testing: tiers 1-3 (in progress)

Thanks,
David

src/hotspot/share/oops/klass.hpp line 525:

523: virtual Klass* array_klass_impl(TRAPS);
524: virtual Klass* array_klass_or_null_impl(int rank);
525: virtual Klass* array_klass_or_null_impl();

I think you should make these pure virtual functions (=0) and remove the bodies in klass.cpp.

I think now we can get rid of the `array_klass_or_null_impl()` function altogether. Instead, `array_klass_or_null` should be declared as `virtual ... = 0` in `Klass` and implemented by the concrete subclasses.

Yes I think you are right - no need to inherit the top-level delegating
functions and override the impl functions, when we can just override the
top-level functions and delete all the impl functions. I'll give that a
whirl.

Thanks for looking at this Ioi and Coleen!

David

[openjdk]

@dholmes-ora this pull request can not be integrated into master due to one or more merge conflicts. To resolve these merge conflicts and update this pull request you can run the following commands in the local repository for your personal fork:

git checkout 8266017
git fetch https://git.openjdk.java.net/jdk master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push

[iklam]

LGTM. Just a small nit about comments.

[coleenp]

Looks great.

[iklam]

Latest version looks good.

[dholmes-ora]

/integrate

[openjdk]

@dholmes-ora Since your change was applied there have been 39 commits pushed to the master branch:

• f75dd80: 8266230: mark hotspot compiler/c2 tests which ignore VM flags
• 9df6cc7: 8264678: Incomplete comment in build.tools.generatecharacter.GenerateCharacter
• 73cfc26: 8266232: compiler.c1.TestRangeCheckEliminated should be run in driver mode
• 3e1b90a: 8266157: Problem list several awt jtreg tests that fail on macOS 11
• 3f9879f: 8266190: mark hotspot compiler/codecache tests which ignore VM flags
• d12e01a: 8264472: Add a test group for running CDS tests with -XX:+VerifySharedSpaces
• b3b2bb2: 8265773: incorrect jdeps message "jdk8internals" to describe a removed JDK internal API
• 2780577: 8196415: Disable SHA-1 Signed JARs
• 21f65f8: 8266206: Build failure after JDK-8264752 with older GCCs
• c71c268: 8266165: TestNoWarningLoopStripMiningIterSet is runnable only on VM w/ G1, Shenandoah, Z and Epsilon
• ... and 29 more: https://git.openjdk.java.net/jdk/compare/7f4a9f68bfd6fd002f79ac989155550db0bcdd20...master

Your commit was automatically rebased without conflicts.

Pushed as commit 23180f8.

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