8258553 Limit number of fields in instance to be considered for scalar replacement

[veresov]

I stumbled upon a test that we have (gc/TestBigObj.java) that has an object with 64k fields and that is scalar replaceable. Doing so puts a lot of strain on the compiler. I ran a few test and benchmarks and the maximum number of fields in scalar-replaced object that I've seen was 59. I think it should be reasonable to set a limit on the number of fields to 512.

---

Progress

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Issue

• JDK-8258553: Limit number of fields in instance to be considered for scalar replacement

Reviewers

• Vladimir Kozlov (@vnkozlov - Reviewer)
• Vladimir Ivanov (@iwanowww - Reviewer)

Download

$ git fetch https://git.openjdk.java.net/jdk pull/1837/head:pull/1837
$ git checkout pull/1837

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[mlbridge]

Webrevs

• 00: Full (84c73d0)

[vnkozlov]

Good.

[openjdk]

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

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

8258553: Limit number of fields in instance to be considered for scalar replacement

Reviewed-by: kvn, vlivanov

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At the time when this comment was updated there had been 30 new commits pushed to the master branch:

• 71ae05d: 8258061: Improve diagnostic information about errors during class redefinition
• 68f2acb: 8252055: Use java.util.HexFormat in java.security
• 1dae45d: 8250523: Remove abortOnException diagnostic option from TestHumongousNonArrayAllocation.java
• 00d80fd: 8258255: Move PtrQueue active flag to SATBMarkQueue
• 853c047: 8258469: Cleanup remaining safefetch test coding
• 1e03ca1: 8258471: "search codecache" clhsdb command does not work
• 3f77a60: 8258582: HttpClient: the HttpClient doesn't explicitly shutdown its default executor when stopping.
• f15528e: Merge
• 30ca0a5: 8247994: Localize javadoc search
• 47c180d: 8258515: javac should issue an error if an annotation is nested in a local class or interface
• ... and 20 more: https://git.openjdk.java.net/jdk/compare/513269d24e806a1f007dd1c3394f3ca20fbb132d...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.

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[iwanowww]

Looks good.

[veresov]

/integrate

[openjdk]

@veresov Since your change was applied there have been 35 commits pushed to the master branch:

• adf0e23: 8257800: CompileCommand TypedMethodOptionMatcher::parse_method_pattern() may over consume
• 06c24e1: 8256213: Remove os::split_reserved_memory
• be41468: 8258696: Temporarily revert use of pattern match instanceof until docs-reference is fixed
• a4f393c: 8258661: Inner class ResponseCacheEntry could be static
• 3c48819: 8169086: DTLS tests fail intermittently with too much loops or timeout
• 71ae05d: 8258061: Improve diagnostic information about errors during class redefinition
• 68f2acb: 8252055: Use java.util.HexFormat in java.security
• 1dae45d: 8250523: Remove abortOnException diagnostic option from TestHumongousNonArrayAllocation.java
• 00d80fd: 8258255: Move PtrQueue active flag to SATBMarkQueue
• 853c047: 8258469: Cleanup remaining safefetch test coding
• ... and 25 more: https://git.openjdk.java.net/jdk/compare/513269d24e806a1f007dd1c3394f3ca20fbb132d...master

Your commit was automatically rebased without conflicts.

Pushed as commit 7f92d18.

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