8287292: Improve TransformKey to pack more kinds of transforms efficiently

[cl4es]

The bespoke caching scheme in jl.invoke.LambdaFormEditor.TransformKey allows keys to be compacted when all byte values of the key fit in 4 bits, otherwise a byte array is allocated and used. This means that all transforms with a kind value above 15 will be forced to allocate and use array comparisons.

Removing unused and folding some transforms to ensure all existing kinds can fit snugly within the 0-15 value range realize a minor improvement to footprint, speed and allocation pressure of affected transforms, e.g. ~300bytes/op reduction in the StringConcatFactoryBootstraps microbenchmark:

Baseline:

Benchmark                                                      Mode  Cnt     Score     Error   Units
SCFB.makeConcatWithConstants                                   avgt   15  2048.475 ?  69.887   ns/op
SCFB.makeConcatWithConstants:?gc.alloc.rate.norm               avgt   15  3487.311 ?  80.385    B/op

Patched:

Benchmark                                                      Mode  Cnt     Score     Error   Units
SCFB.makeConcatWithConstants                                   avgt   15  1961.985 ? 101.519   ns/op
SCFB.makeConcatWithConstants:?gc.alloc.rate.norm               avgt   15  3156.478 ? 183.600    B/op

---

Progress

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Issue

• JDK-8287292: Improve TransformKey to pack more kinds of transforms efficiently

Reviewers

• Jim Laskey (@JimLaskey - Reviewer) ⚠️ Review applies to 001e9d16
• Jorn Vernee (@JornVernee - Reviewer) ⚠️ Review applies to 2be3b25c
• Mandy Chung (@mlchung - Reviewer) ⚠️ Review applies to 612b4ece

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[mlbridge]

Webrevs

• 03: Full - Incremental (bcd79aad)
• 02: Full - Incremental (612b4ece)
• 01: Full - Incremental (2be3b25c)
• 00: Full (001e9d16)

[openjdk]

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

8287292: Improve TransformKey to pack more kinds of transforms efficiently

Reviewed-by: jlaskey, jvernee, mchung

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At the time when this comment was updated there had been 98 new commits pushed to the master branch:

• 777f813: 8268422: Find a better way to select releases in "New API" page
• 22e2067: 8282182: Document algorithm used to encode aarch64 logical immediate operands.
• 37ecbb4: 8277420: Provide a way to copy the hyperlink to a doc element to the clipboard
• 176bb23: 8287200: Test java/lang/management/ThreadMXBean/VirtualThreadDeadlocks.java timed out after JDK-8287103
• ec97da9: 8287352: DockerTestUtils::execute shows incorrect elapsed time
• 140419f: 8286058: AArch64: clarify types of calls
• 6a33974: 8286737: Test vmTestbase/gc/gctests/WeakReference/weak006/weak006.java fails: Last soft reference has not been cleared
• 295be6f: 8287285: Avoid redundant HashMap.containsKey call in java.util.zip.ZipFile.Source.get
• 7cb368b: 8286709: (fc) FileChannel/FileChannelImpl cleanup
• 7eb1559: 8286045: Use ForceGC for cleaner test cases
• ... and 88 more: https://git.openjdk.java.net/jdk/compare/4587337e956ed6f1a59e9d980a09ab9f784fbde0...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.

[mlchung]

LGTM with a couple of suggestions.

[cl4es]

Thanks!

/integrate

[openjdk]

Going to push as commit be93318.
Since your change was applied there have been 98 commits pushed to the master branch:

• 777f813: 8268422: Find a better way to select releases in "New API" page
• 22e2067: 8282182: Document algorithm used to encode aarch64 logical immediate operands.
• 37ecbb4: 8277420: Provide a way to copy the hyperlink to a doc element to the clipboard
• 176bb23: 8287200: Test java/lang/management/ThreadMXBean/VirtualThreadDeadlocks.java timed out after JDK-8287103
• ec97da9: 8287352: DockerTestUtils::execute shows incorrect elapsed time
• 140419f: 8286058: AArch64: clarify types of calls
• 6a33974: 8286737: Test vmTestbase/gc/gctests/WeakReference/weak006/weak006.java fails: Last soft reference has not been cleared
• 295be6f: 8287285: Avoid redundant HashMap.containsKey call in java.util.zip.ZipFile.Source.get
• 7cb368b: 8286709: (fc) FileChannel/FileChannelImpl cleanup
• 7eb1559: 8286045: Use ForceGC for cleaner test cases
• ... and 88 more: https://git.openjdk.java.net/jdk/compare/4587337e956ed6f1a59e9d980a09ab9f784fbde0...master

Your commit was automatically rebased without conflicts.

[openjdk]

@cl4es Pushed as commit be93318.

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