On Thu, 11 Jun 2026 18:26:09 GMT, Aleksey Shipilev <[email protected]> wrote:
>> You can add `assert` here so that future support will notify the lack of
>> support from C2 here.
>
> Maybe? I do not have time for this this week, but I can try next week. What
> exactly are you having in mind? Putting down some feature flags when
> Shenandoah is enabled?
In `fieldLayoutBuilder.cpp`, we have this:
if (UseNullableNonAtomicValueFlattening) {
_nullable_non_atomic_layout_size_in_bytes = new_raw_size;
_null_marker_offset = null_marker_offset;
_null_free_non_atomic_layout_alignment = _payload_alignment;
}
if (UseNullableValueFlattening) {
// For the nullable atomic layout, the size mut be compatible with the
platform capabilities
int nullable_atomic_size = round_up_power_of_2(new_raw_size);
if (nullable_atomic_size <= (int)MAX_ATOMIC_OP_SIZE) {
_nullable_atomic_layout_size_in_bytes = nullable_atomic_size;
_null_marker_offset = null_marker_offset;
}
}
I wonder if it is a good idea to insert a little bit of code here to disable
these when `UseShenandoahGC` is `true` and the layout has oop. What do you
think @fparain?
-------------
PR Review Comment:
https://git.openjdk.org/valhalla/pull/1971#discussion_r3405652859
