On Wed, 17 Jul 2024 18:54:32 GMT, Vladimir Ivanov <vliva...@openjdk.org> wrote:
>> Now it starts to sound concerning... `Klass::set_secondary_supers()`
>> initializes both `_secondary_supers` and `_bitmap` which implies that
>> `Klass::is_subtype_of()` may be called on not yet initialized Klass. It
>> that's the case, it does look like a bug on its own. How is it expected to
>> work when `_secondary_supers` hasn't been set yet?
>
> On a second thought the following setter may be the culprit:
>
> void Klass::set_secondary_supers(Array<Klass*>* secondaries) {
> assert(!UseSecondarySupersTable || secondaries == nullptr, "");
> set_secondary_supers(secondaries, SECONDARY_SUPERS_BITMAP_EMPTY);
> }
>
> It should be adjusted to set `SECONDARY_SUPERS_BITMAP_FULL` instead.
I've spent a while trying to reproduce the problem but I can't.
I was seeing a problem where
`Klass::is_subtype_of(vmClasses::Cloneable_klass())` was being called before
the bitmap had been set. I'm not sure what to think, really. Maybe I should
just back out this change to see what happens.
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PR Review Comment: https://git.openjdk.org/jdk/pull/19989#discussion_r1683174591
