scripts/headerdep.pl

   1 #! /usr/bin/perl
   2 #
   3 # Detect cycles in the header file dependency graph
   4 # Vegard Nossum <vegardno@ifi.uio.no>
   5 #
   6
   7 use strict;
   8 use warnings;
   9
  10 use Getopt::Long;
  11
  12 my $opt_all;
  13 my @opt_include;
  14 my $opt_graph;
  15
  16 &Getopt::Long::Configure(qw(bundling pass_through));
  17 &GetOptions(
  18         help    => \&help,
  19         version => \&version,
  20
  21         all     => \$opt_all,
  22         "I=s"   => \@opt_include,
  23         graph   => \$opt_graph,
  24 );
  25
  26 push @opt_include, 'include';
  27 my %deps = ();
  28 my %linenos = ();
  29
  30 my @headers = grep { strip($_) } @ARGV;
  31
  32 parse_all(@headers);
  33
  34 if($opt_graph) {
  35         graph();
  36 } else {
  37         detect_cycles(@headers);
  38 }
  39
  40
  41 sub help {
  42         print "Usage: $0 [options] file...\n";
  43         print "\n";
  44         print "Options:\n";
  45         print "  --all\n";
  46         print "  --graph\n";
  47         print "\n";
  48         print "  -I includedir\n";
  49         print "\n";
  50         print "To make nice graphs, try:\n";
  51         print "  $0 --graph include/linux/kernel.h | dot -Tpng -o graph.png\n";
  52         exit;
  53 }
  54
  55 sub version {
  56         print "headerdep version 2\n";
  57         exit;
  58 }
  59
  60 # Get a file name that is relative to our include paths
  61 sub strip {
  62         my $filename = shift;
  63
  64         for my $i (@opt_include) {
  65                 my $stripped = $filename;
  66                 $stripped =~ s/^$i\///;
  67
  68                 return $stripped if $stripped ne $filename;
  69         }
  70
  71         return $filename;
  72 }
  73
  74 # Search for the file name in the list of include paths
  75 sub search {
  76         my $filename = shift;
  77         return $filename if -f $filename;
  78
  79         for my $i (@opt_include) {
  80                 my $path = "$i/$filename";
  81                 return $path if -f $path;
  82         }
  83         return;
  84 }
  85
  86 sub parse_all {
  87         # Parse all the headers.
  88         my @queue = @_;
  89         while(@queue) {
  90                 my $header = pop @queue;
  91                 next if exists $deps{$header};
  92
  93                 $deps{$header} = [] unless exists $deps{$header};
  94
  95                 my $path = search($header);
  96                 next unless $path;
  97
  98                 open(my $file, '<', $path) or die($!);
  99                 chomp(my @lines = <$file>);
 100                 close($file);
 101
 102                 for my $i (0 .. $#lines) {
 103                         my $line = $lines[$i];
 104                         if(my($dep) = ($line =~ m/^#\s*include\s*<(.*?)>/)) {
 105                                 push @queue, $dep;
 106                                 push @{$deps{$header}}, [$i + 1, $dep];
 107                         }
 108                 }
 109         }
 110 }
 111
 112 sub print_cycle {
 113         # $cycle[n] includes $cycle[n + 1];
 114         # $cycle[-1] will be the culprit
 115         my $cycle = shift;
 116
 117         # Adjust the line numbers
 118         for my $i (0 .. $#$cycle - 1) {
 119                 $cycle->[$i]->[0] = $cycle->[$i + 1]->[0];
 120         }
 121         $cycle->[-1]->[0] = 0;
 122
 123         my $first = shift @$cycle;
 124         my $last = pop @$cycle;
 125
 126         my $msg = "In file included";
 127         printf "%s from %s,\n", $msg, $last->[1] if defined $last;
 128
 129         for my $header (reverse @$cycle) {
 130                 printf "%s from %s:%d%s\n",
 131                         " " x length $msg,
 132                         $header->[1], $header->[0],
 133                         $header->[1] eq $last->[1] ? ' <-- here' : '';
 134         }
 135
 136         printf "%s:%d: warning: recursive header inclusion\n",
 137                 $first->[1], $first->[0];
 138 }
 139
 140 # Find and print the smallest cycle starting in the specified node.
 141 sub detect_cycles {
 142         my @queue = map { [[0, $_]] } @_;
 143         while(@queue) {
 144                 my $top = pop @queue;
 145                 my $name = $top->[-1]->[1];
 146
 147                 for my $dep (@{$deps{$name}}) {
 148                         my $chain = [@$top, [$dep->[0], $dep->[1]]];
 149
 150                         # If the dep already exists in the chain, we have a
 151                         # cycle...
 152                         if(grep { $_->[1] eq $dep->[1] } @$top) {
 153                                 print_cycle($chain);
 154                                 next if $opt_all;
 155                                 return;
 156                         }
 157
 158                         push @queue, $chain;
 159                 }
 160         }
 161 }
 162
 163 sub mangle {
 164         $_ = shift;
 165         s/\//__/g;
 166         s/\./_/g;
 167         s/-/_/g;
 168         $_;
 169 }
 170
 171 # Output dependency graph in GraphViz language.
 172 sub graph {
 173         print "digraph {\n";
 174
 175         print "\t/* vertices */\n";
 176         for my $header (keys %deps) {
 177                 printf "\t%s [label=\"%s\"];\n",
 178                         mangle($header), $header;
 179         }
 180
 181         print "\n";
 182
 183         print "\t/* edges */\n";
 184         for my $header (keys %deps) {
 185                 for my $dep (@{$deps{$header}}) {
 186                         printf "\t%s -> %s;\n",
 187                                 mangle($header), mangle($dep->[1]);
 188                 }
 189         }
 190
 191         print "}\n";
 192 }