RFR: 8345647: Fix recent NULL usage backsliding in Shenandoah

[Sonia Zaldana Calles]

On Wed, 11 Dec 2024 15:14:06 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

>> Hi all, 
>> 
>> This PR addresses [8345647](https://bugs.openjdk.org/browse/JDK-8345647) addressing uses of `NULL` in Shenandoah. These should be replaced to `null`. 
>> 
>> I verified where those uses are with: 
>> `git show <commit-id> --name-only | while read file; do echo "File: $file"; git diff <commit-id> -- "$file" | grep -n -F 'NULL'; done`
>> 
>> The relevant output: 
>> 
>> File: src/hotspot/cpu/ppc/gc/shenandoah/shenandoahBarrierSetAssembler_ppc.cpp
>> 9:-  // No need for post barrier if storing NULL
>> File: src/hotspot/share/gc/shenandoah/c2/shenandoahBarrierSetC2.cpp
>> 9:-    // must be either an oop or NULL
>> 12:     if (t == TypePtr::NULL_PTR || t == Type::TOP)
>> 
>> 
>> Changes affect comments only. 
>> 
>> Thanks, 
>> Sonia
>
> New JBS issue for the missed cases:
> https://bugs.openjdk.org/browse/JDK-8346008

Hi @kimbarrett, thanks for taking a look. Apologies for missing those. I can follow up with a PR for the remaining changes.

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PR Comment: https://git.openjdk.org/jdk/pull/22647#issuecomment-2536415158