RFR [XXS] : JDK-8081616: build fixes for --disable-warnings-as-errors

[Magnus Ihse Bursie]

On 2015-06-01 19:23, Bertrand Delsart wrote:
> Hi all,
>
> A small open webrev to fix some issues around 
> --disable-warnings-as-errors (this is not a full cleanup):
>
> http://cr.openjdk.java.net/~bdelsart/8081616/webrev.00/webrev/
>
> Without the fix, -Werror is used to compiled native JDK libraries even 
> when the --disable-warnings-as-errors is used.
>
> A lot of these libs are addressed by clearing 
> CFLAGS_WARNINGS_ARE_ERRORS in flags.m4
>
> Lib-jdk.sctp.gmk is a special case because it uses directly -Werror. 
> Instead of modifying SCTP to use CFLAGS_WARNINGS_ARE_ERRORS, I use the 
> mechanism put in place in that file to disable -Werror and control it 
> through the WARNINGS_AS_ERRORS configured value.
I think this patch will require some work to be OK.

First of all, I'm not quite sure I understand what problem you are 
trying to solve. What libraries are compiled with -Werror when 
--disable-warnings-as-errors is used? This should not be the case, and I 
cannot reproduce it on my system.

CFLAGS_WARNINGS_ARE_ERRORS should never be cleared, since that is only 
exported as the mechanism to use for enabling warnings as errors. If no 
compilation includes it (which it should not if warnings-as-errors are 
disabled), it won't affect the build. If CFLAGS_WARNINGS_ARE_ERRORS are 
used even though warnings-as-errors are disabled, then it is this usage 
that should be fixed.

I can see that libsctp is a special case that hard-codes -Werror. But in 
this case we should remove the hard-coding and relying on the system 
setting. This is probably a remnant from before the overall -Werror 
usage, where the authors of a specific lib wanted to enforce a higher 
standard. Also, it might be worth revisiting if 
-Wno-error=unused-parameter is really needed. These things tend to bit-rot.

/Magnus

>
> Best regards,
>
> Bertrand.
>