[lworld] RFR: 8352647: [lworld] Remove larval InlineTypeNode in Unsafe intrinsics

[Jatin Bhateja]

On Wed, 26 Mar 2025 03:15:06 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Hi,
>> 
>> As a step of #1405, I would like to remove the usage of larval value objects in `Unsafe` intrinsics. This patch also tries to make sure that `Unsafe::makePrivateBuffer` and `Unsafe::finishPrivateBuffer` are always inlined, so that larval objects do not cross call boundaries except for invoking object constructors.
>> 
>> Please take a look and review this PR, thanks a lot.
>
> src/hotspot/share/opto/library_call.cpp line 2685:
> 
>> 2683:   ciInlineKlass* vk = type->inline_klass();
>> 2684:   Node* klass = makecon(TypeKlassPtr::make(vk));
>> 2685:   Node* obj = new_instance(klass);
> 
> We have adpoted a similar strategy in lworld-vector 
> 
> https://github.com/openjdk/valhalla/blob/lworld%2Bvector/src/hotspot/share/opto/inlinetypenode.cpp#L1071

We should also emit the IR to mark the larval bit in the object header.
https://github.com/openjdk/valhalla/blob/lworld%2Bvector/src/hotspot/share/opto/inlinetypenode.cpp#L1075

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PR Review Comment: https://git.openjdk.org/valhalla/pull/1406#discussion_r2013322213