On Wed, 17 Jul 2024 17:13:49 GMT, Andrew Haley <a...@openjdk.org> wrote:
>> Another observation while browsing the code: `_secondary_supers_bitmap` >> would be a better name. (Same considerations apply to `_hash_slot`.) > > This is because the C++ runtime does secondary super cache lookups even > before the bitmap has been calculated and the hash table sorted. In this case > the bitmap is zero, so teh search thinks there are no secondary supers. > Setting _bitmap to SECONDARY_SUPERS_BITMAP_FULL forces a linear search. > > I guess there might be a better way to do this. Perhaps a comment is needed? > > I agree about `_secondary_supers_bitmap` name. 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? ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/19989#discussion_r1681571806
