RFR(XS): 8043029: Change 8037816 breaks HS build with older GCC versions which don't support diagnostic pragmas

[David Chase]

I'm not a Reviewer, but I've become rather familiar with this code recently,
and your changes look entirely correct.

And I will sponsor the fix as soon as we do get a Reviewer to comment.

On 2014-05-13, at 3:32 PM, Volker Simonis <volker.simonis at gmail.com> wrote:

> Hi,
> 
> Change 8037816 introduced extra format checking by GCC for custom HS
> printf functions by annotating them with
> __attribute__((format(printf,...)). These checks have been selectively
> disabled with the help of diagnostic pragmas (i.e. #pragma GCC
> diagnostic ignored "-Wformat-nonliteral") in places where these
> functions are called with non-constant format strings.
> 
> Unfortunately, diagnostic pragmas were only introduced in GCC 4.2 (see
> http://gcc.gnu.org/onlinedocs/gcc-4.2.4/gcc/Diagnostic-Pragmas.html#Diagnostic-Pragmas).
> Older GCC versions simply ignore these pragmas and issue a warning.
> 
> The fix to this problem is trivial - only enable
> '__attribute__((format(printf,...))'-annotations for GCC 4.2 and
> above:
> 
> http://cr.openjdk.java.net/~simonis/webrevs/8043029/
> https://bugs.openjdk.java.net/browse/JDK-8043029
> 
> Additionally to the before-mentioned fix, I have also improved the
> version checking for the definition of the various diagnostic pragmas.
> In the original version they would have only been enabled for
> __GNUC_MINOR__ versions greater and equal '6' but nor for GCC 5.0 for
> example. And I've also tried to break some of the overly long lines to
> make them more readable.
> 
> Thank you and best regards,
> Volker
> 
> PS: as always, I kindly ask for a sponsor to push the change once it
> is reviewed :)