8357178: Simplify Class::componentType

[liach]

isArray and null return is now redundant when componentType is changed to an explicit field.

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Issue

• JDK-8357178: Simplify Class::componentType (Enhancement - P5)

Reviewers

• Roger Riggs (@RogerRiggs - Reviewer)

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8357178: Simplify Class::componentType

Reviewed-by: rriggs

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At the time when this comment was updated there had been 117 new commits pushed to the master branch:

• 90e076b: 8357654: [BACKOUT] JDK-8343580: Type error with inner classes of generic classes in functions generic by outer
• 6a07820: 8357285: JSR166 Test case testShutdownNow_delayedTasks failed
• b07da7b: 8357171: Test tools/jpackage/windows/WinOSConditionTest.java fails for non administrator
• ... and 114 more: https://git.openjdk.org/jdk/compare/d5245092249ed400f98711393e25e0ae97990daf...master

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[mlbridge]

Webrevs

• 01: Full - Incremental (f8f0bf65)
• 00: Full (272ee25d)

[jddarcy]

Did you consider calling getComponentType(), which already returns the field?

Are there regression tests for Class::componentType()/Class::getComponentType() somewhere? I didn't see them in the obvious test/jdk/java/lang/Class directory.

[liach]

Did you consider calling getComponentType(), which already returns the field?

I don't think we want an extra indirection here - The logic here is quite simple. Counterargument could be that MethodType::descriptorString calls toMethodDescriptorString, except these methods involve more complex caching and is not simple like this field access.

Are there regression tests for Class::componentType()/Class::getComponentType() somewhere? I didn't see them in the obvious test/jdk/java/lang/Class directory.

They are located in test/jdk/java/lang/constant/TypeDescriptorTest.java.

[jddarcy]

Did you consider calling getComponentType(), which already returns the field?

I don't think we want an extra indirection here - The logic here is quite simple. Counterargument could be that MethodType::descriptorString calls toMethodDescriptorString, except these methods involve more complex caching and is not simple like this field access.

My mental model anyway is that this trivial inline would be something the VM would do readily.

[minborg]

Question: Why was this overload added in the first place, as it seems equivalent to getComponentType()?

[liach]

@minborg It implements a method in TypeDescriptor.OfField.

[liach]

Can anyone review this simple cleanup?

[RogerRiggs]

lgtm

[liach]

Thanks for the reviews!

/integrate

[openjdk]

Going to push as commit 070c84c.
Since your change was applied there have been 124 commits pushed to the master branch:

• 6674771: 8357468: [asan] heap buffer overflow reported in PcDesc::pc_offset() pcDesc.hpp:57
• 236e1b6: 8357401: BigDecimal: Constants ONE_TENTH and ONE_HALF are unused after JDK-8341402
• 85ca081: 8354316: clang/linux build fails with -Wunused-result warning at XToolkit.c:695:9
• ... and 121 more: https://git.openjdk.org/jdk/compare/d5245092249ed400f98711393e25e0ae97990daf...master

Your commit was automatically rebased without conflicts.

[openjdk]

@liach Pushed as commit 070c84c.

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