Andrei Borzenkov <arvidj...@gmail.com> writes:
>> ld: /tmp/conftest-efc530.o: compiled for a big endian system and target is
>> little endian
>> ld: /tmp/conftest-efc530.o: endianness incompatible with that of the
>> selected emulation
>
> This is the same problem we had on powerpc. Your binutils are set to
> use little-endian output by default; we need to explicitly enable
> either big or little endian in this case as well. Could you try
> attached patch to verify?
I'm glad to report that with your new patch, GRUB successfully builds on
GuixSD mips64el with TARGET_CC=clang. I haven't yet tried booting it
though.
>> Your patch works for me with gcc, although config.log shows this warning
>> when building the test program in your new code with the correct flags
>> for gcc (-mabi=32):
>>
>> ld: warning: cannot find entry symbol __start; defaulting to
>> 00000000004000d0
>>
>
> Well, I just reused existing checks in this case; we worry about it later.
Okay. I guess the name of the start symbol depends on the platform and
linker. E.g. boot/mips/loongson/fwstart.S has this:
--8<---------------cut here---------------start------------->8---
.global start,_start,__start
start:
_start:
__start:
--8<---------------cut here---------------end--------------->8---
Other platforms have only '_start', or both 'start' and '_start'.
>> I also worry that linking an O32 executable might be fragile on a pure
>> non-multilib N32 system such as GNU Guix, where we lack even the gcc
>> runtime library (libgcc_s) for O32. For now it seems to work, but I
>> wonder if it might be more robust to do the test compilation with -c and
>> -freestanding?
>>
>
> It is using -nostdlib; is it not enough?
The warning above makes me doubt the portability and future-proofness of
the link step of this test. This problem could be avoided entirely by
omitting the link step. The link step serves no purpose in this test,
and is a potential source of portability problems.
Having said that, if you prefer to keep the link step, I guess it will
probably be okay in practice to define 'start', '_start', and '__start'
as above. Do as you think best.
Thanks for you help.
Mark
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