How to remove unused C/C++ symbols with GCC and ld?

Question

I need to optimize the size of my executable severely (ARM development) and I noticed that in my current build scheme (gcc + ld) unuse

Answer 1

From the GCC 4.2.1 manual, section -fwhole-program:

Assume that the current compilation unit represents whole program being compiled. All public functions and variables with the exception of main and those merged by attribute externally_visible become static functions and in a affect gets more aggressively optimized by interprocedural optimizers. While this option is equivalent to proper use of static keyword for programs consisting of single file, in combination with option --combine this flag can be used to compile most of smaller scale C programs since the functions and variables become local for the whole combined compilation unit, not for the single source file itself.