Re: bfd function to read ELF file image from memory

[Ian Lance Taylor <ian at airs dot com>]

Roland McGrath <roland@redhat.com> writes:

> > > Still, I would just to have one calling interface that handles
> > > 32-bit and 64-bit ELF.  To implement that front-end function I need
> > > a compile-time check I can use in elfcode.h that tells me whether
> > > 32-bit and/or 64-bit targets are being built.  What works?
> > 
> > You can check "#if ARCH_SIZE == 64" or "#if ARCH_SIZE == 32".
> 
> I must be misunderstanding you, or else that can't be right.  I asked about
> how front-end source code can know whether it needs to call just the 32-bit
> function from the 32-bit compile of elfcode.h, just the 64-bit function
> from the 64-bit compile of elfcode.h, or switch between the two at runtime
> based on bfd_get_arch_size. 

I doubt there are any publically visible functions with name changes
from 32-bit to 64-bit.  But there are certainly functions like
bfd_get_gp_size() which look at the BFD to decide where to get the
backend specific information.  You could do something like that,
assuming you put the appropriate hook in the elf_backend_data struct,
which is less intrusive than putting it in the bfd_target struct.

Ian