RFR: JDK-8301074: Replace NULL with nullptr in share/opto/ [v4]

[Johan Sjölen]

On Mon, 6 Mar 2023 16:14:00 GMT, Johan Sjölen <jsjolen at openjdk.org> wrote:

>> Hi, this PR changes all occurrences of NULL to nullptr for the subdirectory share/opto/. Unfortunately the script that does the change isn't perfect, and so we
>> need to comb through these manually to make sure nothing has gone wrong. I also review these changes but things slip past my eyes sometimes.
>> 
>> Here are some typical things to look out for:
>> 
>>     No changes but copyright header changed (probably because I reverted some changes but forgot the copyright).
>>     Macros having their NULL changed to nullptr, these are added to the script when I find them. They should be NULL.
>>     nullptr in comments and logs. We try to use lower case "null" in these cases as it reads better. An exception is made when code expressions are in a comment.
>> 
>> An example of this:
>> 
>> 
>> // This function returns null
>> void* ret_null();
>> // This function returns true if *x == nullptr
>> bool is_nullptr(void** x);
>> 
>> 
>> Note how nullptr participates in a code expression here, we really are talking about the specific value nullptr.
>> 
>> Thanks!
>
> Johan Sjölen has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Explicitly use 0 for null in ARM interpreter

linux-x86 GHA test failed with:

> Unrecognized VM option 'UseCompressedClassPointers'

Unlikely to be a bug in this PR.

-------------

PR: https://git.openjdk.org/jdk/pull/12187