How do I include only used symbols when statically linking with gcc?

Question

I\'m deploying a small program compiled with gcc, 4.3.2-1.1 (Debian). This program will be deployed on virtual machine templates ranging from Debain 5 to bleeding edge Fedor

Answer 1

This issue is related not only to gcc, but to ld(1) too.

By default, gcc doesn't eliminate dead code, you can check this by compiling/linking executable, and then running

objdump -d a.out

which shows you all functions in your executable.

Simple "googling" give this link.

So, to remove unused functions, you need:

• Compile with “-fdata-sections” to keep the data in separate data sections and “-ffunction-sections” to keep functions in separate sections, so they (data and functions) can be discarded if unused.
• Link with “--gc-sections” to remove unused sections.