Add an utility to help checking for missing dependencies

From: Mauro Carvalho Chehab <mchehab@infradead.org>

This tool consumes some time to run, but it is very useful on helping to check
if a dependency is missing. It will print an output like:

DVB_B2C2_FLEXCOP depends on DVB_CORE && 1
DVB_B2C2_FLEXCOP_PCI depends on DVB_B2C2_FLEXCOP && 1
DVB_B2C2_FLEXCOP depends on DVB_LGDT330X && 1 && DVB_PLL && 1 && DVB_MT312 && 1
&& DVB_BCM3510 && 1 && DVB_STV0297 && 1 && DVB_STV0299 && 1 && DVB_ISL6421 && 1
&& DVB_MT352 && 1 && DVB_CORE && 1 && MEDIA_TUNER_SIMPLE && 1 && DVB_CX24123 &&
1 && DVB_NXT200X && 1

In principle, each dependency should be associated to a "depends on" or
"select" clause, or a recursive "depends on".

Warning: The result of this tool should be used just as a hint, since, due to
performance issues, the checks will use a simple grep at the .c files, instead
of a real symbol usage inspection.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 228 insertions, 0 deletions

diff --git a/v4l/scripts/check_deps.pl b/v4l/scripts/check_deps.pl
new file mode 100755
index 000000000..4071a9976
--- /dev/null
+++ b/v4l/scripts/check_deps.pl
@@ -0,0 +1,228 @@
+#!/usr/bin/perl
+
+# Copyright (C) 2008 Mauro Carvalho Chehab <mchehab@infradead.org>
+
+
+use strict;
+use File::Find;
+use Fcntl ':mode';
+use FileHandle;
+
+my $debug=0;
+
+my $SRC = 'linux';
+
+my %export;
+
+#############
+# open_makefile were adapted from analyze_build.pl
+#   by Copyright (C) 2006 Trent Piepho <xyzzy@speakeasy.org>
+
+# Print out some extra checks of Makefile correctness
+my $check = 0;
+
+# Root of source tree
+my $root;
+
+# List of Makefile's opened
+my %makefiles = ();
+
+# For each module that is made up of multiple source files, list of sources
+my %multi = ();
+my $multi_count = 0;
+
+my %config;
+
+my %associate;
+
+sub open_makefile($) {
+	my $file = shift;
+
+	# only open a given Makefile once
+	return if exists $makefiles{$file};
+	$makefiles{$file} = 1;
+
+	$file =~ m|^(.*)/[^/]*$|;
+	my $dir = $1;
+
+	print "opening $root$file (dir=$dir)\n" if ($debug > 2);
+	my $in = new FileHandle;
+	open $in, '<', "$root$file" or die "Unable to open Makefile '$root$file': $!";
+
+	while (<$in>) {
+		# print STDERR "Line: $_";
+		# Skip comment and blank lines
+		next if (/^\s*(#.*)?$/);
+		m/^\s*\-?include/ and die "Can't handle includes! In $file";
+
+		# Handle line continuations
+		if (/\\\n$/) {
+			$_ .= <$in>;
+			redo;
+		}
+		# Eat line continuations in string we will parse
+		s/\s*\\\n\s*/ /g;
+		# Eat comments
+		s/#.*$//;
+
+		if (/^\s*obj-(\S+)\s*([:+]?)=\s*(\S.*?)\s*$/) {
+			print STDERR "Should use '+=' in $file:$.\n$_\n" if ($check && $2 ne '+');
+			my ($var,$targets) = ($1, $3);
+			if ($var =~ /\$\(CONFIG_(\S+)\)$/) {
+				$var = $1;
+			} elsif ($var !~ /^[ym]$/) {
+				print STDERR "Confused by obj assignment '$var' in $file:$.\n$_";
+			}
+			foreach(split(/\s+/, $targets)) {
+				if (m|/$|) { # Ends in /, means it's a directory
+					open_makefile("$dir/$_".'Makefile');
+				} elsif (/^(\S+)\.o$/) {
+					$config{"$dir/$1"} = $var;
+#					printf "%s -> %s\n", $var, $1 if $debug > 1;
+				} else {
+					print STDERR "Confused by target '$_' in $file:$.\n";
+				}
+			}
+			next;
+		}
+		if (/(\S+)-objs\s*([:+]?)=\s*(\S.*?)\s*$/) {
+			my @files = split(/\s+/, $3);
+			map { s|^(.*)\.o$|$dir/\1| } @files;
+			if ($2 eq '+') {
+				# Adding to files
+				print STDERR "Should use ':=' in $file:$.\n$_\n" if ($check && !exists $multi{"$dir/$1"});
+				push @files, @{$multi{"$dir/$1"}};
+			} else {
+				print STDERR "Setting objects twice in $file:$.\n$_\n" if ($check && exists $multi{"$dir/$1"});
+			}
+			$multi{"$dir/$1"} = \@files;
+			next;
+		}
+		if (/^\s*EXTRA_CFLAGS\s*([:+]?)=\s*(\S.*?)\s*$/) {
+			if ($check) {
+				sub allI { /^-I/ or return 0 foreach split(/\s+/, $_[0]);return 1; }
+				my $use = allI($2) ? ':' : '+';
+				print STDERR "Should use '$use=' with EXTRA_CFLAGS in $file:$.\n$_\n"
+				if ($1 ne $use);
+			}
+			next;
+		}
+		print STDERR "Odd line $file:$.\n$_\n" if ($check);
+	}
+	close IN;
+}
+
+#
+#############
+
+sub associate_multi()
+{
+	foreach (keys %multi) {
+		my $name = $_;
+		my @files =  @{$multi{$_}};
+		map { s/^(.*)$/\1.c/ } @files;
+
+		foreach (@files) {
+			my $file = $_;
+			my $var = $config{$name};
+			$associate{$file} = $var;
+			printf "$var -> $file\n" if $debug > 1;
+		}
+		delete $config{$name};
+	}
+	foreach my $file (keys %config) {
+		my $var = $config{$file};
+		$file .= ".c";
+		$associate{$file} = $var;
+		printf "$var -> $file\n" if $debug > 1;
+	}
+}
+
+sub build_exported_symbol_list {
+	my $file = $File::Find::name;
+
+	return if (!($file =~ /\.c$/));
+
+	open IN, $file;
+	while (<IN>) {
+		if (m/EXPORT_SYMBOL.*\(\s*([^\s\)]+)/) {
+			$export{$1} = $file;
+			printf "%s -> %s\n", $file , $1 if $debug > 1;
+		}
+	}
+	close IN;
+}
+
+
+sub find_usage_list {
+	my %depend;
+	my $file = $File::Find::name;
+	my $s;
+
+	return if (!($file =~ /\.c$/));
+
+	open IN, $file;
+	printf "Checking symbols at $file\n" if $debug;
+	while (<IN>) {
+		foreach my $symbol (keys %export) {
+			my $symb_file = $export{$symbol};
+
+			# Doesn't search the symbol at the file that defines it
+			next if ($symb_file eq $file);
+
+			if (m/($symbol)/) {
+				my $var = $associate{$symb_file};
+				if (!$depend{$var}) {
+					printf "$symbol found at $file. It depends on %s\n", $associate{$symb_file} if $debug;
+					$depend{$var} = 1;
+				}
+			}
+		}
+	}
+	close IN;
+
+	foreach (%depend) { $s .= "$_ && "; };
+	$s =~ s/\&\&\ $//;
+	if ($s ne "") {
+		print $associate{$file}." depends on $s\n";
+	}
+}
+
+print <<EOL;
+Dependency check tool for Kernel Symbols.
+
+Copyright(c) 2008 by Mauro Carvalho Chehab <mchehab\@infradead.org>
+This code is licenced under the terms of GPLv2.
+
+This script seeks all .c files under linux/ for their exported symbols. For 
+each exported symbol, it will check what Kconfig symbol is associated. Then, it 
+will cross-check that symbol usage and output a Kconfig depencency table.
+
+WARNING: The result of this tool should be used just as a hint, since, due to
+performance issues, and to simplify the tool, the checks will use a simple grep 
+for the symbol string at the .c files, instead of a real symbol cross-check.
+
+Also, the same symbol may appear twice with different dependencies. This is due
+to the way it checks for symbols. The final dependency is the union (AND) of 
+all showed ones for that symbol.
+
+Further patches improving this tool are welcome.
+
+EOL
+
+print "Checking makefile rules..." if $debug;
+open_makefile("$SRC/drivers/media/Makefile");
+print " ok\n" if $debug;
+
+print "Associating symbols with c files..." if $debug;
+associate_multi();
+print " ok\n" if $debug;
+
+print "finding exported symbols at $SRC..." if $debug;
+find({wanted => \&build_exported_symbol_list, no_chdir => 1}, $SRC);
+print " ok\n" if $debug;
+
+print "finding usage of symbols at $SRC\n" if $debug;
+find({wanted => \&find_usage_list, no_chdir => 1}, $SRC);
+print "finished\n" if $debug;
+