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Vegard Nossum179efcb2008-12-16 12:33:43 +01001#! /usr/bin/perl
2#
3# Detect cycles in the header file dependency graph
4# Vegard Nossum <vegardno@ifi.uio.no>
5#
6
7use strict;
8use warnings;
9
10use Getopt::Long;
11
12my $opt_all;
13my @opt_include;
14my $opt_graph;
15
16&Getopt::Long::Configure(qw(bundling pass_through));
17&GetOptions(
18 help => \&help,
19 version => \&version,
20
21 all => \$opt_all,
Uwe Kleine-König79ff8072009-03-29 15:01:47 +020022 "I=s" => \@opt_include,
Vegard Nossum179efcb2008-12-16 12:33:43 +010023 graph => \$opt_graph,
24);
25
26push @opt_include, 'include';
27my %deps = ();
28my %linenos = ();
29
30my @headers = grep { strip($_) } @ARGV;
31
32parse_all(@headers);
33
34if($opt_graph) {
35 graph();
36} else {
37 detect_cycles(@headers);
38}
39
40
41sub 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
55sub version {
56 print "headerdep version 2\n";
57 exit;
58}
59
60# Get a file name that is relative to our include paths
61sub 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
75sub 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 }
Stephen Hemminger1dcd8102010-03-08 08:24:27 -080083 return;
Vegard Nossum179efcb2008-12-16 12:33:43 +010084}
85
86sub 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
112sub 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.
141sub 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
163sub mangle {
164 $_ = shift;
165 s/\//__/g;
166 s/\./_/g;
167 s/-/_/g;
168 $_;
169}
170
171# Output dependency graph in GraphViz language.
172sub 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}