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

[William Kemper]

On Wed, 5 Apr 2023 16:36:01 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> I have been reading the `openjdk/shenandoah` vs `openjdk/jdk` diff and these are the simple code massages we can do to improve and bullet-proof the code, hopefully without changing the semantics. This would continue with more parts later.
>> 
>> Additional testing:
>>  - [x] macos-aarch64-server-fastdebug (some pre-existing failures)
>
> Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
> 
>   New assert fires, but instead of fixing it, remove useless live_memory completely

src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.cpp line 900:

> 898:     } else {
> 899:       return true;
> 900:         }

This looks off.

src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.cpp line 943:

> 941:     int flags = ShenandoahHeap::HAS_FORWARDED;
> 942:     if (ShenandoahIUBarrier) {
> 943:       // TODO: Shouldn't this be OLD_MARKING too?

Generational mode requires SATB barriers right now - IU mode only has the young generation.

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PR Review Comment: https://git.openjdk.org/shenandoah/pull/245#discussion_r1160044714
PR Review Comment: https://git.openjdk.org/shenandoah/pull/245#discussion_r1160045588