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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
8use strict;
9use warnings;
10
11use Getopt::Long;
12
13my $opt_all;
14my @opt_include;
15my $opt_graph;
16
17&Getopt::Long::Configure(qw(bundling pass_through));
18&GetOptions(
19 help => \&help,
20 version => \&version,
21
22 all => \$opt_all,
23 "I=s" => \@opt_include,
24 graph => \$opt_graph,
25);
26
27push @opt_include, 'include';
28my %deps = ();
29my %linenos = ();
30
31my @headers = grep { strip($_) } @ARGV;
32
33parse_all(@headers);
34
35if($opt_graph) {
36 graph();
37} else {
38 detect_cycles(@headers);
39}
40
41
42sub 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
56sub version {
57 print "headerdep version 2\n";
58 exit;
59}
60
61# Get a file name that is relative to our include paths
62sub 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
76sub 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
87sub 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
113sub 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.
142sub 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
164sub mangle {
165 $_ = shift;
166 s/\//__/g;
167 s/\./_/g;
168 s/-/_/g;
169 $_;
170}
171
172# Output dependency graph in GraphViz language.
173sub 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}
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
8use strict;
9use warnings;
10
11use Getopt::Long;
12
13my $opt_all;
14my @opt_include;
15my $opt_graph;
16
17&Getopt::Long::Configure(qw(bundling pass_through));
18&GetOptions(
19 help => \&help,
20 version => \&version,
21
22 all => \$opt_all,
23 "I=s" => \@opt_include,
24 graph => \$opt_graph,
25);
26
27push @opt_include, 'include';
28my %deps = ();
29my %linenos = ();
30
31my @headers = grep { strip($_) } @ARGV;
32
33parse_all(@headers);
34
35if($opt_graph) {
36 graph();
37} else {
38 detect_cycles(@headers);
39}
40
41
42sub 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
56sub version {
57 print "headerdep version 2\n";
58 exit;
59}
60
61# Get a file name that is relative to our include paths
62sub 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
76sub 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
87sub 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
113sub 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.
142sub 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
164sub mangle {
165 $_ = shift;
166 s/\//__/g;
167 s/\./_/g;
168 s/-/_/g;
169 $_;
170}
171
172# Output dependency graph in GraphViz language.
173sub 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}