FreeBSD/Linux Kernel Cross Reference
sys/scripts/headerdep.pl

     #! /usr/bin/perl
     #
     # Detect cycles in the header file dependency graph
     # Vegard Nossum <vegardno@ifi.uio.no>
     #
     
     use strict;
     use warnings;
     
    use Getopt::Long;
    
    my $opt_all;
    my @opt_include;
    my $opt_graph;
    
    &Getopt::Long::Configure(qw(bundling pass_through));
    &GetOptions(
            help    => \&help,
            version => \&version,
    
            all     => \$opt_all,
            "I=s"   => \@opt_include,
            graph   => \$opt_graph,
    );
    
    push @opt_include, 'include';
    my %deps = ();
    my %linenos = ();
    
    my @headers = grep { strip($_) } @ARGV;
    
    parse_all(@headers);
    
    if($opt_graph) {
            graph();
    } else {
            detect_cycles(@headers);
    }
    
    
    sub help {
            print "Usage: $0 [options] file...\n";
            print "\n";
            print "Options:\n";
            print "  --all\n";
            print "  --graph\n";
            print "\n";
            print "  -I includedir\n";
            print "\n";
            print "To make nice graphs, try:\n";
            print "  $0 --graph include/linux/kernel.h | dot -Tpng -o graph.png\n";
            exit;
    }
    
    sub version {
            print "headerdep version 2\n";
            exit;
    }
    
    # Get a file name that is relative to our include paths
    sub strip {
            my $filename = shift;
    
            for my $i (@opt_include) {
                    my $stripped = $filename;
                    $stripped =~ s/^$i\///;
    
                    return $stripped if $stripped ne $filename;
            }
    
            return $filename;
    }
    
    # Search for the file name in the list of include paths
    sub search {
            my $filename = shift;
            return $filename if -f $filename;
    
            for my $i (@opt_include) {
                    my $path = "$i/$filename";
                    return $path if -f $path;
            }
            return;
    }
    
    sub parse_all {
            # Parse all the headers.
            my @queue = @_;
            while(@queue) {
                    my $header = pop @queue;
                    next if exists $deps{$header};
    
                    $deps{$header} = [] unless exists $deps{$header};
    
                    my $path = search($header);
                    next unless $path;
    
                    open(my $file, '<', $path) or die($!);
                    chomp(my @lines = <$file>);
                   close($file);
   
                   for my $i (0 .. $#lines) {
                           my $line = $lines[$i];
                           if(my($dep) = ($line =~ m/^#\s*include\s*<(.*?)>/)) {
                                   push @queue, $dep;
                                   push @{$deps{$header}}, [$i + 1, $dep];
                           }
                   }
           }
   }
   
   sub print_cycle {
           # $cycle[n] includes $cycle[n + 1];
           # $cycle[-1] will be the culprit
           my $cycle = shift;
   
           # Adjust the line numbers
           for my $i (0 .. $#$cycle - 1) {
                   $cycle->[$i]->[0] = $cycle->[$i + 1]->[0];
           }
           $cycle->[-1]->[0] = 0;
   
           my $first = shift @$cycle;
           my $last = pop @$cycle;
   
           my $msg = "In file included";
           printf "%s from %s,\n", $msg, $last->[1] if defined $last;
   
           for my $header (reverse @$cycle) {
                   printf "%s from %s:%d%s\n",
                           " " x length $msg,
                           $header->[1], $header->[0],
                           $header->[1] eq $last->[1] ? ' <-- here' : '';
           }
   
           printf "%s:%d: warning: recursive header inclusion\n",
                   $first->[1], $first->[0];
   }
   
   # Find and print the smallest cycle starting in the specified node.
   sub detect_cycles {
           my @queue = map { [[0, $_]] } @_;
           while(@queue) {
                   my $top = pop @queue;
                   my $name = $top->[-1]->[1];
   
                   for my $dep (@{$deps{$name}}) {
                           my $chain = [@$top, [$dep->[0], $dep->[1]]];
   
                           # If the dep already exists in the chain, we have a
                           # cycle...
                           if(grep { $_->[1] eq $dep->[1] } @$top) {
                                   print_cycle($chain);
                                   next if $opt_all;
                                   return;
                           }
   
                           push @queue, $chain;
                   }
           }
   }
   
   sub mangle {
           $_ = shift;
           s/\//__/g;
           s/\./_/g;
           s/-/_/g;
           $_;
   }
   
   # Output dependency graph in GraphViz language.
   sub graph {
           print "digraph {\n";
   
           print "\t/* vertices */\n";
           for my $header (keys %deps) {
                   printf "\t%s [label=\"%s\"];\n",
                           mangle($header), $header;
           }
   
           print "\n";
   
           print "\t/* edges */\n";
           for my $header (keys %deps) {
                   for my $dep (@{$deps{$header}}) {
                           printf "\t%s -> %s;\n",
                                   mangle($header), mangle($dep->[1]);
                   }
           }
   
           print "}\n";
   }

Cache object: 0e939c2a4e75d12c7a540f2c9424246d