On Mon, 9 Feb 2026 09:35:48 GMT, Axel Boldt-Christmas <[email protected]> wrote:
> Create a wrapper class which represents the payload of an InlineKlass object. > > The current convention is to use a `void*` representing where the payload > starts, the `InlineKlass*` (as we do not always have a header when flattened) > and a `LayoutKind` (describing the payloads layout). > > I suggest we introduce something like a `ValuePayload` which encapsulate > these properties. As well as a hierarchy built upon these, with the proper > interfaces implemented. > * ValuePayload (Any payload) > * ~RawValuePayload (Payload with holder erased)~ (Removed in favour of > using a static function) > * BufferedValuePayload (Payload of normal heap object) > * FlatValuePayload (Payload of flattened value) > * FlatFieldPayload (Payload of flattened field) > * FlatArrayPayload (Payload of flattened array element) > > The goal is to both make interfaces clearer, and easier to understand. As > well as consolidating the implementation in one place rather than spread > across different subsystems. > > Each type (except RawValuePayload) also allows for the creation of a Handle, > (thread local, or in an OopStorage) for keeping the payload as a thread or > global root. > > The ValuePayload class is also the interface for interacting with the Access > API for InlineKlass objects. > > * Testing > * Running tier 1-4 with preview enabled > * Running app tests with preview enabled > * Running normal tier 1-5 > > #### _Extra Notes:_ > * The `OopHandle` type is there so that we can migrate the JVMTI payload > abstraction implementation to using this instead. (Future RFE) > * Some interfaces got cleaned up. Some are unused. Like the `null_payload` > which was superseded by the `Access::value_store_null`. C1 still uses the > `.null_reset` but if that dependency is removed we should be able to remove > that weird object all together. > * Simply adding the Java to VM transition deep inside the payload code > created a circular include dependency here. So rather than fixing that, I > implemented the relevant bytecodes in the BytecodeInterpreter. This pull request has now been integrated. Changeset: dba91f1b Author: Axel Boldt-Christmas <[email protected]> URL: https://git.openjdk.org/valhalla/commit/dba91f1b9420de5b1b3363858a7957d0dc296de5 Stats: 2217 lines in 39 files changed: 1812 ins; 237 del; 168 mod 8377451: [lworld] Add ValuePayload abstraction Reviewed-by: fparain ------------- PR: https://git.openjdk.org/valhalla/pull/2068
