Relocatable executables

Relocatable executables

[Uros Prestor]

Hello,

I am using gcc/binutils to develop software for an embedded system (MIPS
ELF).  The executable is statically linked at a fixed text address, no
PIC.  At load time I need to relocate the executable at a different
address.  Is there a way to have ld include relocation info in the
executable?

The naive approach of adding the following two lines in the linker
script does not seem to work:

     .rel.text : { *(.rel.text) }
     .rel.data : { *(.rel.rodata) *(.rel.data) }

On the other hand, compiling with PIC and creating a shared library is
too heavy handed.  Is there an easier way to have ld emit enough info in
the ELF file to allow for a load-time relocation?

Thanks in advance,
Uros

P.S.
Please keep me on the cc: list as I am not subscribed to binutils.

--
Uros Prestor
uros.prestor@nexsi.com

Re: Relocatable executables

[H . J . Lu]

On Wed, Aug 22, 2001 at 01:15:50PM -0700, Uros Prestor wrote:
> Hello,
> 
> I am using gcc/binutils to develop software for an embedded system (MIPS
> ELF).  The executable is statically linked at a fixed text address, no
> PIC.  At load time I need to relocate the executable at a different
> address.  Is there a way to have ld include relocation info in the
> executable?
> 

`-q'
`--emit-relocs'
     Leave relocation sections and contents in fully linked
     exececutables.  Post link analysis and optimization tools may need
     this information in order to perform correct modifications of
     executables.  This results in larger executables.


H.J.

Re: Relocatable executables

[Uros Prestor]

"H . J . Lu" wrote:

> `-q'
> `--emit-relocs'
>      Leave relocation sections and contents in fully linked
>      exececutables.  Post link analysis and optimization tools may need
>      this information in order to perform correct modifications of
>      executables.  This results in larger executables.

Thanks, H.J.

My version of ld (2.9.1 with BFD 2.9.1) seems to be too ancient to recognize
--emit-relocs.  Can I do the equivalent of --emit-relocs on 2.9.1 via the
linker script, or do I have to upgrade to a newer version of binutils?

Uros

--
Uros Prestor
uros.prestor@nexsi.com