#! /usr/bin/perl # # 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 $opt_graph; &Getopt::Long::Configure(qw(bundling pass_through)); &GetOptions( help => \&help, version => \&version, all => \$opt_all, I => \@opt_include, graph => \$opt_graph, ); push @opt_include, 'include'; my %deps = (); my %linenos = (); my @headers = grep { strip($_) } @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 undef; } 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"; }