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#!/usr/bin/perl -w

# vi: set ts=4:

# Libstrip - A utility to optimize libraries for specific executables

# Copyright (C) 2001  David A. Schleef 

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of version 2 of the GNU General Public License as

# published by the Free Software Foundation.

#

# This is a surprisingly simple script that gets a list of

# unresolved symbols in a list of executables specified on the

# command line, and then relinks the uClibc shared object file

# with only the those symbols and their dependencies.  This

# results in a shared object that is optimized for the executables

# listed, and thus may not work with other executables.

#

# Example: optimizing uClibc for BusyBox

#  Compile uClibc and BusyBox as normal.  Then, in this

#  directory, run:

#    libstrip path/to/busybox

#  After the script completes, there should be a new

#  libuClibc-0.9.5.so in the current directory, which

#  is optimized for busybox.

#

# How it works:

#  The uClibc Makefiles create libuClibc.so by first creating

#  the ar archive libc.a with all the object files, then links

#  the final libuClibc.so by using 'ld --shared --whole-archive'.

#  We take advantage of the linker command line option --undefined,

#  which pulls in a symbol and all its dependencies, and so relink

#  the library using --undefined for each symbol in place of

#  --whole-archive.  The linker script is used only to avoid

#  having very long command lines.

$topdir="../..";

# This is the name of the default ldscript for shared libs.  The

# file name will be different for other architectures.

$ldscript="/usr/lib/ldscripts/elf_i386.xs";

my @syms;

my @allsyms;

my $s;

while($exec = shift @ARGV){

        #print "$exec\n";

        @syms=`nm --dynamic $exec`;

        for $s (@syms){

                chomp $s;

                if($s =~ m/^.{8} [BUV] (.+)/){

                        my $x = $1;

                        if(!grep { m/^$x$/; } @allsyms){

                                unshift @allsyms, $x;

                        }

                }

        }

}

open(LDSCRIPT, ">ldscript");

print LDSCRIPT "INCLUDE $ldscript\n";

for $s (@allsyms) {

        print LDSCRIPT "EXTERN($s)\n";

}

`gcc -s -nostdlib -Wl,-warn-common -shared \\

        -o libuClibc-0.9.5.so \\

        -Wl,-soname,libc.so.0 -Wl,--script=ldscript \\

        $topdir/libc/libc.a \\

        $topdir/libc/tmp/libgcc-need.a`