Re: Having the GNU linker *not* remove unused symbols...

[Carsten Fuchs]

Hi,

first of all, Maett and Paul, thank you very much for your replies!  :-)

Paul Pluzhnikov wrote:
> > I guess what happens is that when the linker links the executable, it
> > removes all symbols from libcfsLib.a that are unused by the
> > executable.
>
> Not quite: the linker doesn't remove anything from anywhere; it
> simply doesn't pull in the objects that it doesn't need.

Ah, okay.  ;)  My thought was that it first just duplicates or 
"concatenates" everything that I specify on the command line in scratch 
memory, then does a "flood fill" to flag everything that is needed, and 
finally creates the final executable by removing the non-flagged parts 
from scratch memory again.
So as your text about linkers makes clear, my assumption that 
executables are entirely pre-built in (scratch) memory was somewhat wrong.

> You may wish to read this for an explanation:
>  http://webpages.charter.net/ppluzhnikov/linker.html
>
> If you only care about GNU ld, the --whole-archive is a good
> solution. If you care about portability to other linkers, use
> multiple '-u needed_symbol_1' ...
>
> If there are too many needed symbols, another alternative is to
> create an object file which will "pull" them all in:

Great!  Many thanks for your detailed answer!

Best,
Carsten



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