RFR: Cleanups, TODOs, asserts (part 1) [v2]

[William Kemper]

On Thu, 6 Apr 2023 17:35:22 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> src/hotspot/share/gc/shenandoah/shenandoahBarrierSet.inline.hpp line 1:
>> 
>>> 1: /*
>> 
>> Almost all changes in this PR are "cosmetic".   Some of the changes in ShenandoahBarrierSet.inline.hpp appear to be beyond cosmetic.  Maybe this should be addressed in a separate PR.
>> 
>> Thinking out loud here: is the new_value argument for write_ref_field_post() only needed for IU-style post-write barriers?
>
> What is non-cosmetic in removing `oop newVal`? It does not seem to be used anywhere. Maybe it would indeed be needed for IU, let's reintroduce it then?

It should be fine to remove it - the post barrier is only for generational mode. The IU barrier needs the new value in its _pre_ write barrier.

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PR Review Comment: https://git.openjdk.org/shenandoah/pull/245#discussion_r1160091796