Re: [Lxr-general] Finding unreferenced functions

[Tom S. <to...@pl...>]

On Thu, 2005-01-06 at 07:25 -0800, Michael O'Connor wrote:
> Hi,
> 
> Apologies if this has been asked before. I'm wondering if anyone's tried using
> lxr on a codebase to find unreferenced / unused functions. I tried this on a C
> / C++ codebase I've been working in and found it very useful as part of a
> clean-up exercise.

Here is what I have done.  I am not sure exactly what version of LXR I
am running, here is the CVS Id from the ident script:
  # $Id: ident,v 1.6 1998/04/30 11:58:16 argggh Exp $

Here are some bits to add to Common.pm:
sub uiref {
    my ($desc, $pr, @args) = @_;
    return("<a href=\"unref".
           &urlargs(($pr ? "pr=$pr" : ""),
                    @args).
           "\"\>$desc</a>");
}

This goes at the end of titleexpand:
    } elsif ($who eq 'unref') {
        return($Conf->sourcerootname.' unreferenced identifier search');
    }

This goes after the 'find' part in modeexpand:
    if ($who eq 'unref') {
        push(@mlist, "<b><i>unreferenced identifier search</i></b>");
    } else {
        push(@mlist, &uiref("unreferenced identifier search", ""));
    }

This goes after the 'find' part in varlinks:
            } elsif ($who eq 'unref') {
                $vallink = &uiref($val, $identifier, "$var=$val");
            }

========================================================================
Here is my file called "unref".  It is just a modification of the ident
script, and it belongs in the same directory.

#!/usr/bin/perl

# unref --      Find unreferenced identifiers
#
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

######################################################################

use lib 'lib/';
use LXR::Common;
use LXR::Config;
use DB_File;

my $sort_by_identifier = 0;

sub unref {
    print("<form method=get action=\"unref\">\n");

    foreach ($Conf->allvariables) {
        if ($Conf->variable($_) ne $Conf->vardefault($_)) {
            print("<input type=hidden name=\"",$_, "\" ",
                  "value=\"", $Conf->variable($_), "\">\n");
        }
    }

    print(
          "Pathname regexp: <input type=text name=\"pr\" ",
          "value=\"",$pathname_regexp,"\" size=60>\n",
          "<input type=submit value=\"Go get it\">\n",
          "</form>\n"
          );


    tie(%xref, "DB_File", $Conf->dbdir."/xref",
        O_RDONLY, 0644, $DB_HASH) ||
        &fatal("Could not open \"".$Conf->dbdir."/xref\"");

    tie(%fileidx, "DB_File", $Conf->dbdir."/fileidx",
        O_RDONLY, 0644, $DB_HASH) ||
        &fatal("Could not open \"".$Conf->dbdir."/fileidx\"");

    if ($pathname_regexp) {
        while (($identifier, $data) = each(%xref)) {
            # Ignore C++ destructors, because they are implicitly
            # referenced by delete()
            if ($identifier =~ /^~/) {
                next;
            }

            @refs = split(/\t/, $data);

            unless (@refs) {
                next;
            }

            @filtered_refs = grep(/^R/, @refs);
            if (int(@filtered_refs) > 2) {
                next;
            }

            foreach (@filtered_refs) {
                if (/^R(.+):([\d,]+)/) {
                    $fnam = $fileidx{$1};
                    @fpos = split(/,/, $2);
                    unless ($fnam =~ /$pathname_regexp/) {
                        next;
                    }
                    # ignore definitions in .h files
                    if ($fnam =~ /\.h$|\._h$/) {
                        next;
                    }
                    if ($#fpos == 0) {
                        if ($sort_by_identifier) {
                            $unref_ident{$identifier} = &fileref(
                                "$fnam, line $fpos[0]",
                                "/$fnam",
                                $fpos[0]
                            );
                        } else {
                            $unref_ident{
                                &fileref(
                                    "$fnam, line $fpos[0]",
                                    "/$fnam",
                                    $fpos[0]
                                )
                            } = $identifier;
                        }
                    }
                }
            }
        }

        untie(%fileidx);
        untie(%xref);

        @keylist = keys(%unref_ident);
        print("<h1>Unreferenced identifiers (", $#keylist, ")</h1>\n");
        print("<table>\n");
	if ($sort_by_identifier) {
            print("<tr><th>Identifier</th><th>File</th></tr>\n");
            foreach $identifier (sort(@keylist)) {
                print(
                      "<tr><td>",
                      &idref($identifier, $identifier),
                      "</td><td>",
                      $unref_ident{$identifier},
                      "</td></tr>\n"
                      );
            }
        } else {
            print("<tr><th>File</th><th>Identifier</th></tr>\n");
            foreach $fref (sort(@keylist)) {
                print(
                      "<tr><td>",
                      $fref,
                      "</td><td>",
                      &idref($unref_ident{$fref}, $unref_ident{$fref}),
                      "</td></tr>\n"
                      );
            }
        }
        print("</table>\n");

    } else {
        print(
              "<p>You must specify a pathname regexp.",
              "  Use '.' to match all files."
              );
    }
}

($Conf, $HTTP, $Path) = &init;
$pathname_regexp = $HTTP->{'param'}->{'pr'};

&makeheader('unref');
&unref;
&makefooter('unref');