scripts/headerdep.pl

   1 #! /usr/bin/env perl
   2 # SPDX-License-Identifier: GPL-2.0
   3 #
   4 # Detect cycles in the header file dependency graph
   5 # Vegard Nossum <vegardno@ifi.uio.no>
   6 #
   7
   8 use strict;
   9 use warnings;
  10
  11 use Getopt::Long;
  12
  13 my $opt_all;
  14 my @opt_include;
  15 my $opt_graph;
  16
  17 &Getopt::Long::Configure(qw(bundling pass_through));
  18 &GetOptions(
  19         help    => \&help,
  20         version => \&version,
  21
  22         all     => \$opt_all,
  23         "I=s"   => \@opt_include,
  24         graph   => \$opt_graph,
  25 );
  26
  27 push @opt_include, 'include';
  28 my %deps = ();
  29 my %linenos = ();
  30
  31 my @headers = grep { strip($_) } @ARGV;
  32
  33 parse_all(@headers);
  34
  35 if($opt_graph) {
  36         graph();
  37 } else {
  38         detect_cycles(@headers);
  39 }
  40
  41
  42 sub help {
  43         print "Usage: $0 [options] file...\n";
  44         print "\n";
  45         print "Options:\n";
  46         print "  --all\n";
  47         print "  --graph\n";
  48         print "\n";
  49         print "  -I includedir\n";
  50         print "\n";
  51         print "To make nice graphs, try:\n";
  52         print "  $0 --graph include/linux/kernel.h | dot -Tpng -o graph.png\n";
  53         exit;
  54 }
  55
  56 sub version {
  57         print "headerdep version 2\n";
  58         exit;
  59 }
  60
  61 # Get a file name that is relative to our include paths
  62 sub strip {
  63         my $filename = shift;
  64
  65         for my $i (@opt_include) {
  66                 my $stripped = $filename;
  67                 $stripped =~ s/^$i\///;
  68
  69                 return $stripped if $stripped ne $filename;
  70         }
  71
  72         return $filename;
  73 }
  74
  75 # Search for the file name in the list of include paths
  76 sub search {
  77         my $filename = shift;
  78         return $filename if -f $filename;
  79
  80         for my $i (@opt_include) {
  81                 my $path = "$i/$filename";
  82                 return $path if -f $path;
  83         }
  84         return;
  85 }
  86
  87 sub parse_all {
  88         # Parse all the headers.
  89         my @queue = @_;
  90         while(@queue) {
  91                 my $header = pop @queue;
  92                 next if exists $deps{$header};
  93
  94                 $deps{$header} = [] unless exists $deps{$header};
  95
  96                 my $path = search($header);
  97                 next unless $path;
  98
  99                 open(my $file, '<', $path) or die($!);
 100                 chomp(my @lines = <$file>);
 101                 close($file);
 102
 103                 for my $i (0 .. $#lines) {
 104                         my $line = $lines[$i];
 105                         if(my($dep) = ($line =~ m/^#\s*include\s*<(.*?)>/)) {
 106                                 push @queue, $dep;
 107                                 push @{$deps{$header}}, [$i + 1, $dep];
 108                         }
 109                 }
 110         }
 111 }
 112
 113 sub print_cycle {
 114         # $cycle[n] includes $cycle[n + 1];
 115         # $cycle[-1] will be the culprit
 116         my $cycle = shift;
 117
 118         # Adjust the line numbers
 119         for my $i (0 .. $#$cycle - 1) {
 120                 $cycle->[$i]->[0] = $cycle->[$i + 1]->[0];
 121         }
 122         $cycle->[-1]->[0] = 0;
 123
 124         my $first = shift @$cycle;
 125         my $last = pop @$cycle;
 126
 127         my $msg = "In file included";
 128         printf "%s from %s,\n", $msg, $last->[1] if defined $last;
 129
 130         for my $header (reverse @$cycle) {
 131                 printf "%s from %s:%d%s\n",
 132                         " " x length $msg,
 133                         $header->[1], $header->[0],
 134                         $header->[1] eq $last->[1] ? ' <-- here' : '';
 135         }
 136
 137         printf "%s:%d: warning: recursive header inclusion\n",
 138                 $first->[1], $first->[0];
 139 }
 140
 141 # Find and print the smallest cycle starting in the specified node.
 142 sub detect_cycles {
 143         my @queue = map { [[0, $_]] } @_;
 144         while(@queue) {
 145                 my $top = pop @queue;
 146                 my $name = $top->[-1]->[1];
 147
 148                 for my $dep (@{$deps{$name}}) {
 149                         my $chain = [@$top, [$dep->[0], $dep->[1]]];
 150
 151                         # If the dep already exists in the chain, we have a
 152                         # cycle...
 153                         if(grep { $_->[1] eq $dep->[1] } @$top) {
 154                                 print_cycle($chain);
 155                                 next if $opt_all;
 156                                 return;
 157                         }
 158
 159                         push @queue, $chain;
 160                 }
 161         }
 162 }
 163
 164 sub mangle {
 165         $_ = shift;
 166         s/\//__/g;
 167         s/\./_/g;
 168         s/-/_/g;
 169         $_;
 170 }
 171
 172 # Output dependency graph in GraphViz language.
 173 sub graph {
 174         print "digraph {\n";
 175
 176         print "\t/* vertices */\n";
 177         for my $header (keys %deps) {
 178                 printf "\t%s [label=\"%s\"];\n",
 179                         mangle($header), $header;
 180         }
 181
 182         print "\n";
 183
 184         print "\t/* edges */\n";
 185         for my $header (keys %deps) {
 186                 for my $dep (@{$deps{$header}}) {
 187                         printf "\t%s -> %s;\n",
 188                                 mangle($header), mangle($dep->[1]);
 189                 }
 190         }
 191
 192         print "}\n";
 193 }