For development- or debugging-purpose I like to use something like the following piece of code:

# somewhere at the beginning of the code
$SIG{__WARN__} = \&Warning;
$SIG{__DIE__}  = \&Die;

# anywhere
# ------------------------------------------------------------
sub Warning {
    my @text = @_;
    warn "------------------------------------------------------------
+\n";
    warn "WARNING: @text\n";
    my $count = 0;
    {
    my ($package, $filename, $line, $sub) = caller($count);
    last unless defined $line;
    warn sprintf("%02i %5i %-35s %-20s\n", $count++, $line, $sub,
             $filename);
    redo;
    }
} # Warning
# ------------------------------------------------------------
sub Die {
    my @text = @_;
    warn "------------------------------------------------------------
+\n";
    warn "FATAL ERROR: @text\n";
    my $count = 0;
    {
    my ($package, $filename, $line, $sub) = caller($count);
    last unless defined $line;
    warn sprintf("%02i %5i %-35s %-20s\n", $count++, $line, $sub,
             $filename);
    redo;
    }
    exit 1;
} # Die
# ------------------------------------------------------------
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This installs "signal handlers" for die and warn which are executed every time when the functions die and warn are executed and print a backtrace on how the line the warning or die was produced was reached...