Re: objcopy copies not only symbols asked?

[Fergus Henderson <fjh at cs dot mu dot OZ dot AU>]

On 24-Feb-2003, Gyurki, Istvan (MED) <Istvan dot Gyurki at med dot ge dot com> wrote:
> I have a .o file about 1 meg size. I'd like to extract only one symbol from
> it, using:
>   objcopy --strip-all -K symbolname from.o to.o
> 
> objcopy does the job, however the new file containing only one symbol wil be
> about 800k.
> I do not think that the symbol takes up that much space, so for me it seems
> that objcopy only removes symbol reference, but does not actually eliminate
> everything.
> 
> My question is; is there a way to create .o file containing only the
> required symbol, and not more?

If you build with -ffunction-sections and -fdata-sections, then you
may be able to use the linker to do this (e.g. "ld -r --gc-sections
-u symbolname -o to.o from.o"; I haven't actually tried this).

But if the object file was not built with -ffunction-sections and
-fdata-sections, then I think you're out of luck. 

-- 
Fergus Henderson <fjh at cs dot mu dot oz dot au>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.