On Tue, 28 Apr 2026 13:57:13 GMT, Joel Sikström <[email protected]> wrote:
>> Hello, >> >> Embdedded flat contended fields might not be included in the class' OopMap >> if there are no other oop fields in the holder class. >> >> Flat fields are handled separately in fieldLayoutBuilder.cpp, resulting in >> the current `_oop_count` not being updated if a flat field contains oops. >> This is OK, since the oop fields are handled at a later point in time. >> However, for contended fields, which are part of the contended group, >> embedded oop fields are only tracked if: `cg->oop_count() > 0`, which is not >> guaranteed to be true. >> >> I've written a test to see if the oop field is included in the class' OopMap >> and also changed the `_oop_count` field `_has_embedded_oops`, and changed >> that to a boolean property, which is how we've used it so far. >> >> Since embedded fields in flat paylods are not tracked in `cg->oop_fields()`, >> we can't do the assert that is currently there, so I just removed that. >> >> Testing: >> * New test fails without the fixes in fieldLayoutBuilder and passes with >> fixes >> * Running Oracle's tier1-3 >> >> --------- >> - [x] I confirm that I make this contribution in accordance with the >> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). > > Joel Sikström has updated the pull request incrementally with one additional > commit since the last revision: > > Test enhancement test/hotspot/jtreg/runtime/valhalla/inlinetypes/ContendedFlatFieldOopMap.java line 39: > 37: * @enablePreview > 38: * @run driver jdk.test.lib.helpers.ClassFileInstaller > jdk.test.whitebox.WhiteBox > 39: * @run main/othervm -XX:-RestrictContended Nit: it might be good to guard against this being set: `@requires vm.opt.RestrictContended == null` Or maybe even: `@requires vm.opt.RestrictContended == null | vm.opt.RestrictContended == "false"` ------------- PR Review Comment: https://git.openjdk.org/valhalla/pull/2371#discussion_r3159571287
