Re: bug(?) in ppc relocations

[Geoff Keating <geoffk at cygnus dot com>]

> Date: Mon, 20 Mar 2000 23:02:18 +0200
> From: Momchil Velikov <velco@fadata.bg>

> 	    addend -= (sdata->sym_hash->root.u.def.value
> 		       + sdata->sym_hash->root.u.def.section->output_section->vma
> 		       + sdata->sym_hash->root.u.def.section->output_offset);
>                       
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> 	  }                                   |
> 	  break;                              |
>                               This looks somewhat suspicious.
> sdata->sym_hash is the _SDA_BASE_ symbol and its value,
> as far as I can understand, should not be affected by output_offset,
> right ?

Why not?  The value of all other symbols are affected by their
output_offset.

> Consider the following scenario:
>  1. The linker creates a linker section .sdata and _SDA_BASE_ with
> offset 32768
>  2. The linker outputs to the output .sdata some input .sdata
>  3. The linker appends the linker .sdata to output .sdata
> Now data items in the first .sdata are at offset < -32768 relative to 
> _SDA_BASE_ and the linker exits with relocation overflow error.
> 
> If the above analisys is correct one can think of (at least) two
> options:
>   (a) make sure the linker section is output first, or
>   (b) remove the underlined line above.

You want (a).  I'm not sure how you managed to get the scenario above
to happen; I suspect your linker script.



-- 
- Geoffrey Keating <geoffk@cygnus.com>