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Removing unused functions and data from executable

Started by Omnipotent Nov 19, 2004 at 2:34 PM 4 replies 1.4k views

Original Post

Nov 19, 2004 at 2:34 PM

Hi All, I was wondering if there is a gcc linker option to remove unused functions and data from the executable? I can't seem to find one. With the .net compiler and linker I can use these options: -Gy (for compiling) -OPT:REF (For linking) Is there any equivalents for the gcc compiler? Thanks!!

Nice Coder

Nov 22, 2004 at 11:55 PM

-o3 should do it (optimizations should remove things linke that),

DENC

marijnh

Nov 23, 2004 at 8:00 AM

I do not think -O3 does that, -s (strip) is what you want.

Qw3r7yU10p!

Nov 23, 2004 at 8:42 AM

strip

Fruny

Nov 23, 2004 at 9:30 AM

Top result on google for "gcc discard unused functions".

markr

Nov 23, 2004 at 11:43 AM

Some things should be removed by default anyway.

As far as I'm aware, the compiler/linker should automatically (and probably without optimisation settings)

- Ditch unused static functions and variables
- Linker will ignore objects which aren't required (unless output is a library itself, or an option is specified to keep them)

Because the compile/link process is separate, the compiler cannot throw away functions that aren't used as it doesn't know what they're linked against. Likewise, the linker probably cannot move functions around in memory to compact space from unused ones, as it doesn't know about static items etc, which might be using them anyway.

Note to petewood: strip does not remove any unused functions or variables from the executable, just debugging info / unneeded symbols.

Mark

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