For instance is it possible to get the line number of a label?

If you remember them, yes ;-)

#!/usr/bin/perl

use strict;
use warnings;

my $i;

my $FOO_LABEL_LINE = __LINE__; FOO: {
    $i++;
    redo FOO if $i < 10;
}   

print "Label FOO is at line $FOO_LABEL_LINE\n";
__END__
Label FOO is at line 8
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but I'm afraid this isn't what you want...