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[Patch bfd/mach-o] some tweaks to bfd_mach_o_canonicalize_one_reloc

Iain Sandoe developer@sandoe-acoustics.co.uk
Thu Feb 23 09:00:00 GMT 2012 
Hi Tristan,
On 23 Feb 2012, at 08:28, Tristan Gingold wrote:

> Thank you for fixing this issue, I was not sure about the endiannes  
> when I wrote this code and I don't have access anymore to a ppc  
> darwin system.

It's not necessary to have a PPC system (the problem I saw was trying  
to objdump PPC code on an x86 system) - it will affect any case where  
the endian-ness is different between host & target.

I was using:
echo " .long _foo " | as -arch ppc -o t.o
as a test-case ;)

[I see the problem on x86 because I have a partial port to PPC  
enabled, which means that objdump is now able to list PPC relocs - I  
can send you a patch, off-list if you like (it's not ready to post  
yet)].

I'll look at moving the representation to bytes - getting rid of the  
r_symbolnum field would probably be quite easy.

.. but it's bit-field layout within bytes that's the issue, so I think  
we still would need:

union {
   unsigned char access;
   struct
    {
	unsigned char r_pcrel:1, r_length:2, r_extern:1,  r_type:4;
    } rev;
    {
	unsigned char r_type:4, r_extern:1, r_length:2, r_pcrel:1;
    } fwd;
} bfd_mach_o_reloc_field_swap;

... or a set of macros to do the same.
* this has to be activated by TARGET-endian-ness != HOST-endian-ness
... it's not enough to look at the target.

... anyway it will have to go on the TODO ;) ... other things to  
attack first.
cheers
Iain
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