Re: Bug#717557: gcc-4.8: can't compile working 64bit kernel with 32bit userspace gcc-4.8
Am 20.10.2013 22:58, schrieb Ben Hutchings:
> On Sun, 2013-10-20 at 22:21 +0200, Matthias Klose wrote:
>> Am 20.10.2013 00:25, schrieb Ben Hutchings:
>>> On Sat, 2013-10-19 at 23:38 +0200, Matthias Klose wrote:
>>>> Control: severity -1 important Control: tags -1 + moreinfo
>>>>
>>>>>> In file included from <command-line>:0:0:
>>>>>> /usr/include/stdc-predef.h:30:26: fatal error: bits/predefs.h:
>>>>>> No such file
>>>>> or directory
>>>>>> #include <bits/predefs.h> ^
>>>>> compilation terminated.
>>>>>
>>>>> It looks like I can avoid this by changing the compile tests to
>>>>> use the -nostdinc option. But this change may possibly cause
>>>>> other problems, and neither the pre-included header nor the fact
>>>>> that -nostdinc disables it seem to be documented.
>>>>
>>>> please attach the test program and the command line options used for
>>>> this test case. I think the issue is within the kernel build system
>>>> not being prepared for multiarch and -nostdinc.
>>>
>>> gcc-4.8 -m64 -x c -c /dev/null
>>
>> works for me on a current sid/i386. I assume that gcc-4.8-multilib is
>> installed?
>
> No, it works if that's installed. But gcc-X.Y-multilib was previously only
> needed for building with a 64-bit C library, not for building a 64-bit
> kernel.
>
> If this kernel configuration was actually failing to build without
> gcc-4.8-multilib, I wouldn't mind so much. The problem is that it's built
> wrongly now. Maybe some later version of the kernel will be changed to
> detect or work around this problem, but we have to assume people will still
> try to build older versions not using -nostdinc for some time to come.
Is this due to the missing /usr/include/asm symlink shipped in gcc-multilib?
It's not ideal, and I think I did file a bug report that this should be
shipped in one of the glibc packages, but can't find it anymore.
> The options to deal with this include: 1. Make missing headers non-fatal
> while pre-including <stdc-predef.h>.
that would be the responsibility of those packages using non-standard options
like -nostdinc.
> 2. Disable pre-inclusion of <stdc-predef.h>.
no, done upstream to conform to standards.
> 3. Make 32-bit gcc fail to compile anything with -m64 if gcc-X.Y-multilib
> is not installed, even if -nostdinc is used.
welcome to multiarch, and thanks for upstreaming patches to fix these issues.
> 4. Make gcc-X.Y depend on gcc-X.Y-multilib on architectures where it
> exists.
well, then you can merge these again. the whole point to have them separate
were bug reports about being forced to install the non-defaults multilibs by
default.
5. Install the whole glibc headers into the multiarch header path. Would fix
some other things too, like allowing multiarch configurations for non-glibc
based triplets. And I assume it would allow your build to fail.
Matthias
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