RFR: 8294314: Minimize disabled warnings in hotspot [v2]

[Magnus Ihse Bursie]

On Sat, 24 Sep 2022 03:33:34 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

>> Magnus Ihse Bursie has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - ppc64 triggers shift-negative-value on gcc :-(
>>  - s390 triggers shift-negative-value on gcc :-(
>
> There used to be more comments around the warning disables. The Windows ones
> had comments that gave titles to the numeric codes. And I think there were
> some comments that discussed why a warning was disabled rather than fixing
> code. I don't know when that all disappeared, but it was quite a while ago,
> and I still miss that commentary.

@kimbarrett I promised a list of warnings that were previously globally (within hotspot) disabled, but are not now. Here it is:

### gcc


address
cast-function-type
char-subscripts
empty-body
misleading-indentation
sequence-point
shift-negative-value
strict-overflow


### clang


char-subscripts
delete-non-virtual-dtor
misleading-indentation
mismatched-tags
missing-field-initializers
shift-negative-value
tautological-compare
undefined-var-template


### visual studio


4100 - 'identifier': unreferenced formal parameter
4127 - conditional expression is constant
4201 - nonstandard extension used: nameless struct/union
4351  - new behavior: elements of array ‘array’ will be default initialized (according to google, but it is undocumented!!!)
4511 - 'class': copy constructor was implicitly defined as deleted
4512 - 'class': assignment operator was implicitly defined as deleted
4514 - 'function': unreferenced inline function has been removed

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

PR: https://git.openjdk.org/jdk/pull/10414