Re: Patch for ppc _SDA_BASE_ value

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

   Date: Thu, 23 Mar 2000 22:27:43 +0200
   From: Momchil Velikov <velco@fadata.bg>

   >    >    +  /* Make sure _SDA_BASE_ and _SDA2_BASE_ are at offset <= 32768 from the
   >    >    +     beginning of the respective output section.  */
   >    > 
   >    > That isn't the right check, though.  What you really want to ensure is
   >    > that _SDA_BASE_ (_SDA2_BASE_) is at an offset <= 32768 from the start
   >    > of where the .sdata (.sdata2) section is in the output file.
   >    > 
   >    > Consider
   >    >     .data : { *(.data) *(.sdata) *(.sdata2) }
   >    > where the input .data sections are larger than 65536 bytes in total.
   >
   >    I see. How about adding a call to a new backend function, say 
   >    something like find_suitable_defaults_for_special_symbols(),
   >    in elf_bfd_final_link(), somewhere before the loop which calls
   >    elf_link_input_bfd(), which function in the PPC case would
   >    traverse all the .sdata sections in all the input bfd's,
   >    get the range [first small data item address, last small data item
   >    address]
   >    and put _SDA_BASE_ somewhere in between ?
   >
   > I think you could do this in size_dynamic_sections.

   But neither output_section->vma nor output_offset are initialized
   at the time size_dynamic_sections is called. How about
   ldemul_after_allocation() ?

Oh yeah.  Might as well do it in a callback from final_link, then, as
you suggested.  Or elf32-ppc.c could simply override final_link, and
call the default one after setting the symbol values.

Ian