[PATCH 4/4 v2] fix build errors with gcc6

[David Holmes]

On 17/05/2016 5:39 AM, Guido Trentalancia wrote:
> Hello Andrew !
>
> On Mon, 16/05/2016 at 11.18 -0400, Andrew Hughes wrote:
>
> [...]
>
>> While I agree that is a suitable and unproblematic backport, my
>> approach
>> so far has been to continue building with the older C++ standard,
>> which
>> means explicitly requesting it on newer versions of GCC where the
>> default
>> has changed. That's what my fix, 8151841, did. You could potentially
>> look
>> at supporting C++11 in OpenJDK 9, but I don't think it's appropriate
>> for
>> earlier versions. Even if sufficient changes can be made to get
>> OpenJDK
>> to build and run (and there were a lot of failures when I looked), it
>> results in changing the ABI of the resulting binaries. All in all, I
>> think
>> it's too risky to resolve in older JDKs in that way, and I'd prefer
>> to
>> just retain existing behaviour as much as possible.
>>
>> It seems that you're still seeing breakage on 9 because the new
>> HotSpot
>> build system has gone in and regressed some of 8151841 (see [0]). I'm
>> looking at fixing this now, and will also see about backporting
>> 8151841
>> to 8u.
>>
>> [0] https://bugs.openjdk.java.net/browse/JDK-8156980
>
>
> I recommend applying the patch that I submitted to the different lists.
>
> I believe supporting the new standard is the way forward.

Eventually yes, but that will be in 9u and/or 10. We have ranges of 
compilers that are "officially" supported for different release trains - 
too old or too new and you're generally on your own. We can support 
newer toolchains but not at the expense of older ones; and for 8u only 
if the 8u project lead thinks it is reasonable to add this in.

David
-----

>
> Unfortunately, at the moment I have no time to follow up the other
> build issues with OpenJDK9, but I suggest to adopt the same approach,
> i.e. patching the code and/or the build system to support the new
> standard.
>
> Regards,
>
> Guido
>