RFR: 8329750: Change Universe functions to return more specific Klass* types

[Dean Long]

On Fri, 5 Apr 2024 11:56:11 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

> We have various functions in Universe that returns Klass* where they could be returning TypeArrayKlass* and ObjArrayKlass* instead. If we change these functions we could get rid of some casts in the code. Does this seem like a reasonable change?

src/hotspot/share/classfile/systemDictionary.cpp line 370:

> 368:     }
> 369:   } else {
> 370:     k = Universe::typeArrayKlass(t);

Suggestion:

    TypeArrayKlass* tak = Universe::typeArrayKlass(t);
    k = tak->array_klass(ndims, CHECK_NULL);

src/hotspot/share/classfile/systemDictionary.cpp line 371:

> 369:   } else {
> 370:     k = Universe::typeArrayKlass(t);
> 371:     k = k->array_klass(ndims, CHECK_NULL);

I assume the cast was an attempt to de-virtualize the array_klass() call, so it is better not to use Klass* here.

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PR Review Comment: https://git.openjdk.org/jdk/pull/18652#discussion_r1554362911
PR Review Comment: https://git.openjdk.org/jdk/pull/18652#discussion_r1554363063