[OpenBIOS] cross-pcc compilation issue with GCC 4.5.0

[Segher Boessenkool]

>> > So until then the GCC folks' answer is: If your code uses compile time
>> > options that change the ABI of your compiler, you need to compile a
>> > compiler (well, libgcc) with those options, too.
>>
>> No, that is not the party line.
>
> Huh?  If you use ABI changing options then you need libraries that match.
> This
> includes libgcc.  In rare cases it may be possible to get limited
> iteroperation, but this is the exception rather than the rule.

Sure, but in that case GCC itself should select a matching multilib,
or do whatever else is necessary to make -mregparm useful at all.

See also comment #4 on PR41055.


> You can't assume that an object/library (in particular libgcc) compiled
> for
> one target environment will work on a different target, even if they
> nominally
> use the same ABI.

Sure.

> For example in a linux userspace environment the correct
> way
> to indicate division by zero may be a raise/kill syscall. Obviously this
> is
> completely bogus in a bare metal environment.

Well, in the case at hand, dividing by zero is wrong /per se/, so
we should figure out why that happened.

> If you want to use the wrong toolchain (e.g. a linux targeted compiler for
> bare metal applications such as bootloaders or kernels) then you should
> expect
> to have to jump though hoops. The hacks required vary by both architecture
> and
> compiler version, and range from making sure you never write particular
> code
> sequences to providing your own implementation of all the libgcc routines.
> This is an internal compiler ABI, so the requirements may change without
> warning.

Building with a powerpc-eabi toolchain should work though, and it doesn't
either if I understand correctly.


Segher