#! /usr/bin/perl -w
use strict;

# Usage: $0 foo.a bar.a ...
#     or $0 foo.o bar.o ...

my %sym2file = ();

foreach my $def_filename (@ARGV) {
	open(DEF, "nm --defined-only --extern-only '$def_filename' |")
	  or die "Can't open nm pipe for $def_filename";
	while(<DEF>) {
		my @F = split;
		my $symtype = $F[1];
		my $sym = $F[2];
		# We currently ignore weak symbols.  I hope this doesn't bite us...
		if ($sym && $symtype !~ /\A[VW]\z/) {
			if (defined($sym2file{$sym})) {
				die "duplicate symbol $sym in $sym2file{$sym} and $def_filename";
			}
			$sym2file{$sym} = $def_filename;
		}
	}
}

foreach my $undef_filename (@ARGV) {
	open(UNDEF, "nm --undefined-only --extern-only '$undef_filename' |")
	  or die "Can't open nm pipe for $undef_filename";
	my %deps = ();
	while(<UNDEF>) {
		my @F = split;
		#print "<", join(">, <", @F), ">\n";
		my $sym = $F[1];
		if ($sym) {
			my $def_filename = $sym2file{$sym};
			if (defined($def_filename) && $def_filename && $def_filename ne $undef_filename) {
				$deps{$def_filename} = 0;
			}
		}
	}
	foreach my $def_filename (keys %deps) {
		#print "$undef_filename $def_filename\n";
		print "$def_filename $undef_filename\n";
	}
}

#for i in `find -name '*.a'`;do nm --defined-only --extern-only "$i"|perl -nae 'print "  \"$F[2]\", '"'$i'"',\n" if $F[2];';done