Re: bfd_perform_relocation() and split fields

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

   Date: Wed, 17 Nov 1999 08:49:20 -0600
   From: Eric DeVolder <devolder@evsx.com>

   > The CPU specific hook is already there: the special_function field in
   > the howto structure.  Just make that do whatever you need your
   > relocation to do.

   The call to special_function occurs way too early in bfd_perform_relocation().
   There are several statements that perform calculations or modify reloc_entry
   that would not be able to "preserve" a split-field value all the way thru to
   where the bits are actually placed back into the insn. What I'm suggesting is
   a hook right before the switch(howto-size) statement that gives you a chance
   to munge the reloc value before it gets inserted.

Just do all that stuff in your special_function code.  You won't need
most of it anyhow; most of what bfd_perform_relocation does is pretty
bogus.

I would not accept a patch which added a new hook when you could just
use the existing special_function hook instead.

   > Note that in the ``new'' linker approach, bfd_perform_relocation is
   > not used while linking.

   I'm not familiar with this...is there a pointer available? or email thread?

See the top of bfd/linker.c.

Ian