This patch fixes various issues found with abstract value classes where the assumption was that we have a concrete value class but we actually could have an abstract value class as well.
The main issue found is that a concrete value class is represented with an `InlineKlass` while an abstract value class is represented with an `InstanceKlass`. Therefore, we cannot cast the latter to `InlineKlass`. While working on this, I checked all `is_inlinetype()` uses and found more issues. I also found issues around the `Arrays.copyOf/copyOfRange` intrinsic but left it as follow-up work and filed [JDK-8382226](https://bugs.openjdk.org/browse/JDK-8382226) for it. Here is a list of fixes included in this patch, together with corresponding tests: 1. `GraphKit::get_layout_helper()`: Wrong old assumption that nullable implies not-flat. 2. Checking whether we have a load/store from/to a field of an empty value class: a. C1: `GraphBuilder::access_field()`, for static and instance field. b. C2: `Parse::do_get_xxx()`, for loading c. C2: `Parse::do_set_xxx()`, for storing 3. `arraycopy` instrinsic: Not bailing out when src or dest is a flat abstract value class array - in this case we don't know the layout. We currently hit an assert due to an invalid cast, assuming concrete value classes when an array is flat. Additional changes: - Added some more asserts - Some small code cleanups Thanks, Christian --------- - [x] I confirm that I make this contribution in accordance with the [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). ------------- Commit messages: - more - more changes to macroArrayCopy.cpp - update macroArrayCopy.cpp - fixes Changes: https://git.openjdk.org/valhalla/pull/2325/files Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=2325&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8380525 Stats: 313 lines in 8 files changed: 260 ins; 6 del; 47 mod Patch: https://git.openjdk.org/valhalla/pull/2325.diff Fetch: git fetch https://git.openjdk.org/valhalla.git pull/2325/head:pull/2325 PR: https://git.openjdk.org/valhalla/pull/2325
