kbuild: export-symbol usage report generator

The following patch provides the ability to generate a report of
	(1) All the exported symbols and their in-kernel-module usage count
	(2) For each module, lists the modules and their exported symbols, on
	                  which it depends.

	the report can be generated by executing:
	perl scripts/export_report

The tool warns if the modules are not build using MODVERSIONING.
Signed-off-by: NRam Pai <linuxram@us.ibm.com>
Signed-off-by: NSam Ravnborg <sam@ravnborg.org>

scripts/export_report.pl

+#!/usr/bin/perl -w
+#
+# (C) Copyright IBM Corporation 2006.
+#	Released under GPL v2.
+#	Author : Ram Pai (linuxram@us.ibm.com)
+#
+# Usage: export_report.pl -k Module.symvers [-o report_file ] -f *.mod.c
+#
+
+use Getopt::Std;
+use strict;
+
+sub numerically {
+	my $no1 = (split /\s+/, $a)[1];
+	my $no2 = (split /\s+/, $b)[1];
+	return $no1 <=> $no2;
+}
+
+sub alphabetically {
+	my ($module1, $value1) = @{$a};
+	my ($module2, $value2) = @{$b};
+	return $value1 <=> $value2 || $module2 cmp $module1;
+}
+
+sub print_depends_on {
+	my ($href) = @_;
+	print "\n";
+	while (my ($mod, $list) = each %$href) {
+		print "\t$mod:\n";
+		foreach my $sym (sort numerically @{$list}) {
+			my ($symbol, $no) = split /\s+/, $sym;
+			printf("\t\t%-25s\t%-25d\n", $symbol, $no);
+		}
+		print "\n";
+	}
+	print "\n";
+	print "~"x80 , "\n";
+}
+
+sub usage {
+        print "Usage: @_ -h -k Module.symvers  [ -o outputfile ] \n",
+	      "\t-f: treat all the non-option argument as .mod.c files. ",
+	      "Recommend using this as the last option\n",
+	      "\t-h: print detailed help\n",
+	      "\t-k: the path to Module.symvers file. By default uses ",
+	      "the file from the current directory\n",
+	      "\t-o outputfile: output the report to outputfile\n";
+	exit 0;
+}
+
+sub collectcfiles {
+        my @file = `cat .tmp_versions/*.mod | grep '.*\.ko\$'`;
+        @file = grep {s/\.ko/.mod.c/} @file;
+	chomp @file;
+        return @file;
+}
+
+my (%SYMBOL, %MODULE, %opt, @allcfiles);
+
+if (not getopts('hk:o:f',\%opt) or defined $opt{'h'}) {
+        usage($0);
+}
+
+if (defined $opt{'f'}) {
+	@allcfiles = @ARGV;
+} else {
+	@allcfiles = collectcfiles();
+}
+
+if (not defined $opt{'k'}) {
+	$opt{'k'} = "Module.symvers";
+}
+
+unless (open(MODULE_SYMVERS, $opt{'k'})) {
+	die "Sorry, cannot open $opt{'k'}: $!\n";
+}
+
+if (defined $opt{'o'}) {
+	unless (open(OUTPUT_HANDLE, ">$opt{'o'}")) {
+		die "Sorry, cannot open $opt{'o'} $!\n";
+	}
+	select OUTPUT_HANDLE;
+}
+#
+# collect all the symbols and their attributes from the
+# Module.symvers file
+#
+while ( <MODULE_SYMVERS> ) {
+	chomp;
+	my (undef, $symbol, $module, $gpl) = split;
+	$SYMBOL { $symbol } =  [ $module , "0" , $symbol, $gpl];
+}
+close(MODULE_SYMVERS);
+
+#
+# collect the usage count of each symbol.
+#
+foreach my $thismod (@allcfiles) {
+	unless (open(MODULE_MODULE, $thismod)) {
+		print "Sorry, cannot open $thismod: $!\n";
+		next;
+	}
+	my $state=0;
+	while ( <MODULE_MODULE> ) {
+		chomp;
+		if ($state eq 0) {
+			$state = 1 if ($_ =~ /static const struct modversion_info/);
+			next;
+		}
+		if ($state eq 1) {
+			$state = 2 if ($_ =~ /__attribute__\(\(section\("__versions"\)\)\)/);
+			next;
+		}
+		if ($state eq 2) {
+			if ( $_ !~ /0x[0-9a-f]{7,8},/ ) {
+				next;
+			}
+			my $sym = (split /([,"])/,)[4];
+			my ($module, $value, $symbol, $gpl) = @{$SYMBOL{$sym}};
+			$SYMBOL{ $sym } =  [ $module, $value+1, $symbol, $gpl];
+			push(@{$MODULE{$thismod}} , $sym);
+		}
+	}
+	if ($state ne 2) {
+		print "WARNING:$thismod is not built with CONFIG_MODVERSION enabled\n";
+	}
+	close(MODULE_MODULE);
+}
+
+print "\tThis file reports the exported symbols usage patterns by in-tree\n",
+	"\t\t\t\tmodules\n";
+printf("%s\n\n\n","x"x80);
+printf("\t\t\t\tINDEX\n\n\n");
+printf("SECTION 1: Usage counts of all exported symbols\n");
+printf("SECTION 2: List of modules and the exported symbols they use\n");
+printf("%s\n\n\n","x"x80);
+printf("SECTION 1:\tThe exported symbols and their usage count\n\n");
+printf("%-25s\t%-25s\t%-5s\t%-25s\n", "Symbol", "Module", "Usage count",
+	"export type");
+
+#
+# print the list of unused exported symbols
+#
+foreach my $list (sort alphabetically values(%SYMBOL)) {
+	my ($module, $value, $symbol, $gpl) = @{$list};
+	printf("%-25s\t%-25s\t%-10s\t", $symbol, $module, $value);
+	if (defined $gpl) {
+		printf("%-25s\n",$gpl);
+	} else {
+		printf("\n");
+	}
+}
+printf("%s\n\n\n","x"x80);
+
+printf("SECTION 2:\n\tThis section reports export-symbol-usage of in-kernel
+modules. Each module lists the modules, and the symbols from that module that
+it uses.  Each listed symbol reports the number of modules using it\n");
+
+print "~"x80 , "\n";
+while (my ($thismod, $list) = each %MODULE) {
+	my %depends;
+	$thismod =~ s/\.mod\.c/.ko/;
+	print "\t\t\t$thismod\n";
+	foreach my $symbol (@{$list}) {
+		my ($module, $value, undef, $gpl) = @{$SYMBOL{$symbol}};
+		push (@{$depends{"$module"}}, "$symbol $value");
+	}
+	print_depends_on(\%depends);
+}