# ...
my $lineNum;
sub SetLineNum { $lineNum= 1+(caller(0))[2]; }
while(  <DATA>  ) {
    $lineNum++;
# ...
        eval "\n#line $lineNum $0\n$_\n; 1"
          or  die $@;
# ...
}
# ...

BEGIN { SetLineNum }
__END__
# ...