Re: Qn regarding building an application of smallest size for ARM-11 using gcc

[Andrew Haley <aph at gcc dot gnu dot org>]

Ingo Krabbe writes:
 > Am Dienstag, 27. Juni 2006 06:22 schrieb Binesh:

 > > We are trying to build an application for ARM-11 using gcc and the
 > > related auto make suite) that would occupy minimal size.
 > >
 > > After adding the -Os and -mthumb we noticed that the size of the
 > > stripped executable with a dependency on libc.so and libz.so was about
 > > 87K.
 > > However, when we statically linked it the stripped size grew to 510 K.
 > > We removed all code that uses any of string library or stdio and
 > > instead use only system calls such as ioctl, read, write, mmap and
 > > munmap. (verified using the symbol dumped out by readelf)
 > > Despite this the size remains at 510K.

Don't guess why.  Try linking with -Wl,-Map,app.map

This will give you a map file that tells you exactly why everything
gets linked.

 > > Trying to link with -nostdlib fails as it refers to undefined
 > > reference to ioctl, read, write, mmap and munmap.
 > > Trying to link with -nostartfiles brought down the size to only 502K.
 > >
 > > Do the sys call routines need std libs to be linked in?
 > > Is there an alternative to reduce the size of the statically linked
 > > exe? (Assuming that it might be difficult to migrate all code to asm)

Can't you just use a small asm version of those syscalls?  You've got
source for glibc, so writing the syscalls should only take a few
hours.

Andrew.