TOMOYO Linux Cross Reference
Linux/scripts/headerdep.pl

   #! /usr/bin/env perl
   # SPDX-License-Identifier: GPL-2.0
   #
   # 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";
 }

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