RFR: 8286562: GCC 12 reports some compiler warnings [v2]

[Yasumasa Suenaga]

On Wed, 11 May 2022 11:48:00 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>> Yasumasa Suenaga has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Avoid pragma error in before GCC 12
>
> The harfbuzz disabled warning looks good, so build changes are approved. You'll still need approval for the rest of the changes.
> 
> While it's not my place really to say about the code changes, I think hiding the warnings with pragmas like this is the least attractive option. But if the code owners are okay with it...

Thanks @magicus for your review!

> While it's not my place really to say about the code changes, I think hiding the warnings with pragmas like this is the least attractive option. But if the code owners are okay with it...

Agree, so I fixed bugs which were found out by compiler warnings in this PR - they are in libjli.
I think we can ignore the others because they are already checked in other methods (e.g. `assert`), or due to structure of `Array` class which has payload in `_data[1]` (and it is also checked in `assert`).

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PR: https://git.openjdk.java.net/jdk/pull/8646