[OE-core] [PATCH 1/1] grub 1.99: fix build for gcc 4.7

[Khem Raj]

On Fri, Apr 13, 2012 at 4:43 PM, Kamble, Nitin A
<nitin.a.kamble at intel.com> wrote:
>
>
>> -----Original Message-----
>> From: openembedded-core-bounces at lists.openembedded.org
>> [mailto:openembedded-core-bounces at lists.openembedded.org] On Behalf Of
>> Khem Raj
>> Sent: Friday, April 13, 2012 1:21 PM
>> To: Patches and discussions about the oe-core layer
>> Subject: Re: [OE-core] [PATCH 1/1] grub 1.99: fix build for gcc 4.7
>>
>> On Fri, Apr 13, 2012 at 2:41 AM, Robert Yang
>> <liezhi.yang at windriver.com> wrote:
>> > There was an error when build with gcc 4.7 (FC 17 64bit):
>> > | fs/zfs/zfs.c: In function 'get_filesystem_dnode':
>> > | fs/zfs/zfs.c:1449:7: error: dereferencing type-punned pointer will
>> > | break strict-aliasing rules [-Werror=strict-aliasing]
>> > ......
>> > cc1: all warnings being treated as errors
>> >
>> > While compare the compile command between gcc 4.4.4 and gcc 4.7.0,
>> > they are the same (both of them have -Wall and -Werror), it seems
>> that
>> > gcc
>> > 4.7.0 has changed its algorithm for the strict aliasing check, but I
>> > didn't find the related information from its release note.
>> >
>> > Add "-fno-strict-aliasing" to gcc's option would fix the problem,
>> this
>> > would disable the optimization for strict-aliasing.
>>
>> This seems a bit more than whats needed. You could try adding -Wno-
>> error=strict-aliasing to CFLAGS
>>
>> on another note. I do not see this failing with gcc-4.7(target
>> compiler) here when I build grub for qemux86 so I am a bit puzzled
>>
>
>
> Khem,
>  There is another grub recipe issue, it is building target binaries with distro compiler. Probably because of that you did not see issue with 4.7 cross compiler. We have fix for that issue now.

hmmm interesting that clarifies. So I guess once you fix it to do
_proper_ cross compile build then I guess the problem gets fixed when
we use gcc 4.6 but as soon as we move to gcc-4.7 this will reappear so
in any case this issue needs to fixed in a good manner I think
in anycase.