RFR: 8303489: Add a test to verify classes in vmStruct have unique vtables [v2]

[Alex Menkov]

On Thu, 2 Mar 2023 22:17:27 GMT, Chris Plummer <cjplummer at openjdk.org> wrote:

>> vmStruct contains a lot of entries which should have vtable == null
>> I added logging of some stats to the test, on win-x64-fastdebug it reports:
>> total: 861, no vtable: 503, no_vtable_with_super: 24
>> if test would log everything with no vtable, test log is truncated
>
> In that case is it worth listing the "no vtable" classes that have a superclass? Are they somehow more interesting than those without a superclass?

If superclass is set then it's the type which describes VM class (but some JM classes have super == null)
Maybe the test should report all Types with CInt: false, CStr: false, JPrimitive: false, Oop: false, Ptr: false
Looks like these entries correspond declare_toplevel_type/declare_type in vmStruct

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PR: https://git.openjdk.org/jdk/pull/12820