RFR: 8218164: Improve local control of compiler warnings

[David Holmes]

On 1/02/2019 4:12 pm, Kim Barrett wrote:
>> On Feb 1, 2019, at 12:50 AM, David Holmes <david.holmes at oracle.com> wrote:
>>
>> Hi Kim,
>>
>> On 1/02/2019 10:44 am, Kim Barrett wrote:
>>> Please review this extension to the existing support for locally
>>> disabling various compiler warnings.  There are also a few updates of
>>> existing code to use the new mechanisms.  (There are some additional
>>> opportunities to use these new mechanisms, but some were in code that
>>> Oracle doesn't test, like Win32, so I left them alone.)
>>> (Obviously one should not disable warnings lightly, but sometimes one
>>> does what one must.)
>>> There are several pieces to this change.
>>> First, utilities/compilerWarnings.hpp is refactored to have
>>> compiler-specific variants, similar to globalDefinitions.hpp.  This
>>> hadn't been done previously because only gcc (and clang) had
>>> non-trivial definitions.
>>> Second, implemented PRAGMA_DIAG_PUSH/POP for Visual Studio.  Still no
>>> implementations for xlc or solstudio though.
>>> Third, added a couple of compiler-specific warning disabling macros:
>>> PRAGMA_DISABLE_GCC_WARNING(option_string)  // also applies to clang
>>> PRAGMA_DISABLE_MSVCPP_WARNING(num)
>>> They have useful implementations for the respective compilers and
>>> empty definitions otherwise.
>>> (I'm open to suggestions for better names, esp. for "MSVCPP".)
>>
>> This all seems quite reasonable to me. On the naming ... if the file has to use visCPP perhaps the macro should use VISCPP rather than MSVCPP ?
> 
> Thanks.
> 
> I’d be okay with that too.  Let’s see if anyone else has any preference.
> visCPP only appears a handful of times, and comes from the build system.

Yep.

> The way we currently identify this platform for these warning controls and
> similar things is by looking for _MSC_VER.  

Yes though that of course dates way back to the original Microsoft C 
compiler tools for DOS :)

> The actual product is
> Microsoft Visual C++ (“often abbreviated to MSVC” - Wikipedia).

That's the old name, now (and for a while) it's Microsoft Visual Studio.

> In retrospect, “MSVC” seems like a better choice than MSVCPP.

Agreed.

David

> 
>> Thanks,
>> David
>>
>>> CR:
>>> https://bugs.openjdk.java.net/browse/JDK-8218164
>>> Webrev:
>>> http://cr.openjdk.java.net/~kbarrett/8218164/open.00/
>>> Testing:
>>> mach5 tier1
> 
>