Root/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
7use strict;
8use warnings;
9
10use Getopt::Long;
11
12my $opt_all;
13my @opt_include;
14my $opt_graph;
15
16&Getopt::Long::Configure(qw(bundling pass_through));
17&GetOptions(
18    help => \&help,
19    version => \&version,
20
21    all => \$opt_all,
22    "I=s" => \@opt_include,
23    graph => \$opt_graph,
24);
25
26push @opt_include, 'include';
27my %deps = ();
28my %linenos = ();
29
30my @headers = grep { strip($_) } @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    }
83
84    return undef;
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}
194

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