Re: relocations with addenda

[Nick Clifton <nickc at redhat dot com>]

Hi Stuart,

> I am attempting to compile a simple program on my i386 machine for an ARM 
> target.  In doing this, GCC produces a relocation section in its output file 
> (.rel.text).  ld then produces a .rel.text segment in its output when run with 
> the --emit-relocs option.  This relocation section is of the no-addenda 
> variety and is incompatible with the system on which I am attempting to run 
> my program.  Said system requires a .rela.text section for its relocations 
> (i.e. one with addenda values).
> 
> ld doesn't seem to have a run-time option for converting the .rel.text 
> sections of its input to .rela.text sections in its output.  Is there any way 
> to enable such a conversion?  

Unfortunately no.  The ARM port of LD gas GAS use REL type relocations
which store the addend in the instruction.  What you need is a port
that uses RELA relocations where the addend is stored in a separate
field in the relocation structure itself.

> Can one adjust or patch the source code to accomplish this?

This is possible, although it would probably take a lot of testing to
make sure that it was done correctly.  Feel free to try however.
There are a lot of other ports of GAS and LD that use RELA type
relocations so you can look at these for examples of what needs to be
done.

Cheers
        Nick