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kbuild: Add namespacecheck

From:  Sam Ravnborg <sam@ravnborg.org>
To:  Andrew Morton <akpm@osdl.org>, Linus Torvalds <torvalds@osdl.org>, linux-kernel@vger.kernel.org
Subject:  kbuild: Add namespacecheck
Date:  Mon, 30 Aug 2004 21:41:58 +0200

# This is a BitKeeper generated diff -Nru style patch.
#
# ChangeSet
#   2004/08/29 10:17:02+02:00 kaos@ocs.com.au 
#   kbuild: Add 'make namespacecheck'
#   
#   make namespacecheck lists globally visible symbols that are not used
#   outside the file that defines them.  These symbols are candidates for
#   static declarations.  It also lists multiply defined symbols.
#   namespace.pl knows about lots of special cases in the kernel code,
#   including exported symbols and conglomerate objects.
#   
#   The patch also corrects the usage of scripts/reference*.pl, they need
#   $(src).
#   
#   Signed-off-by: Keith Owens <kaos@ocs.com.au>
#   Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
#   
#   Index: 2.6.9-rc1/Makefile
#   ===================================================================
# 
# Makefile
#   2004/08/29 09:27:51+02:00 kaos@ocs.com.au +5 -2
#   kbuild: Add 'make namespacecheck'
# 
# scripts/namespace.pl
#   2004/08/29 09:53:21+02:00 kaos@ocs.com.au +416 -0
#   kbuild: Add 'make namespacecheck'
# 
# scripts/namespace.pl
#   2004/08/29 09:53:21+02:00 kaos@ocs.com.au +0 -0
#   BitKeeper file /home/sam/bk/kbuild/scripts/namespace.pl
# 
diff -Nru a/Makefile b/Makefile
--- a/Makefile	2004-08-30 21:25:24 +02:00
+++ b/Makefile	2004-08-30 21:25:24 +02:00
@@ -1123,8 +1123,11 @@
 		| xargs $(PERL) -w scripts/checkversion.pl
 
 buildcheck:
-	$(PERL) scripts/reference_discarded.pl
-	$(PERL) scripts/reference_init.pl
+	$(PERL) $(src)/scripts/reference_discarded.pl
+	$(PERL) $(src)/scripts/reference_init.pl
+
+namespacecheck:
+	$(PERL) $(src)/scripts/namespace.pl
 
 endif #ifeq ($(config-targets),1)
 endif #ifeq ($(mixed-targets),1)
diff -Nru a/scripts/namespace.pl b/scripts/namespace.pl
--- /dev/null	Wed Dec 31 16:00:00 196900
+++ b/scripts/namespace.pl	2004-08-30 21:25:24 +02:00
@@ -0,0 +1,416 @@
+#!/usr/bin/perl -w
+#
+#	namespace.pl.  Sun Aug 29 2004
+#
+#	Perform a name space analysis on the linux kernel.
+#
+#	Copyright Keith Owens <kaos@ocs.com.au>.  GPL.
+#
+#	Invoke by changing directory to the top of the kernel object
+#	tree then namespace.pl, no parameters.
+#
+#	Tuned for 2.1.x kernels with the new module handling, it will
+#	work with 2.0 kernels as well.  Last change 2.6.9-rc1.
+#
+#	The source must be compiled/assembled first, the object files
+#	are the primary input to this script.  Incomplete or missing
+#	objects will result in a flawed analysis.  Compile both vmlinux
+#	and modules.
+#
+#	Even with complete objects, treat the result of the analysis
+#	with caution.  Some external references are only used by
+#	certain architectures, others with certain combinations of
+#	configuration parameters.  Ideally the source should include
+#	something like
+#
+#	#ifndef CONFIG_...
+#	static
+#	#endif
+#	symbol_definition;
+#
+#	so the symbols are defined as static unless a particular
+#	CONFIG_... requires it to be external.
+#
+
+require 5;	# at least perl 5
+use strict;
+use File::Find;
+
+my $nm = "/usr/bin/nm -p";
+my $objdump = "/usr/bin/objdump -s -j .comment";
+
+if ($#ARGV != -1) {
+	print STDERR "usage: $0 takes no parameters\n";
+	die("giving up\n");
+}
+
+my %nmdata = ();	# nm data for each object
+my %def = ();		# all definitions for each name
+my %ksymtab = ();	# names that appear in __ksymtab_
+my %ref = ();		# $ref{$name} exists if there is a true external reference to $name
+my %export = ();	# $export{$name} exists if there is an EXPORT_... of $name
+
+&find(\&linux_objects, '.');	# find the objects and do_nm on them
+&list_multiply_defined();
+&resolve_external_references();
+&list_extra_externals();
+
+exit(0);
+
+sub linux_objects
+{
+	# Select objects, ignoring objects which are only created by
+	# merging other objects.  Also ignore all of modules, scripts
+	# and compressed.  Most conglomerate objects are handled by do_nm,
+	# this list only contains the special cases.  These include objects
+	# that are linked from just one other object and objects for which
+	# there is really no permanent source file.
+	my $basename = $_;
+	$_ = $File::Find::name;
+	s:^\./::;
+	if (/.*\.o$/ &&
+		! (
+		m:/built-in.o$:
+		|| m:/piggy.o$: || m:/bootsect.o$:
+		|| m:/boot/setup.o$: || m:^modules/: || m:^scripts/:
+		|| m:/compressed/: || m:/vmlinux-obj.o$:
+		|| m:boot/bbootsect.o$: || m:boot/bsetup.o$:
+		|| m:arch/ia64/scripts/check_gas_for_hint.o$:
+		|| m:arch/ia64/lib/__divsi3.o$:
+		|| m:arch/ia64/lib/__udivsi3.o$:
+		|| m:arch/ia64/lib/__modsi3.o$:
+		|| m:arch/ia64/lib/__umodsi3.o$:
+		|| m:arch/ia64/lib/__divdi3.o$:
+		|| m:arch/ia64/lib/__udivdi3.o$:
+		|| m:arch/ia64/lib/__moddi3.o$:
+		|| m:arch/ia64/lib/__umoddi3.o$:
+		|| m:arch/ia64/ia32/ia32.o$:
+		|| m:net/sched/sched.o$:
+		|| m:fs/romfs/romfs.o$:
+		|| m:fs/ramfs/ramfs.o$:
+		|| m:fs/nls/nls.o$:
+		|| m:drivers/video/video.o$:
+		|| m:drivers/scsi/sd_mod.o$:
+		|| m:drivers/media/media.o$:
+		|| m:drivers/ide/ide-detect.o$:
+		|| m:drivers/ide/pci/idedriver-pci.o$:
+		|| m:drivers/cdrom/driver.o$:
+		|| m:net/netlink/netlink.o$:
+		|| m:fs/vfat/vfat.o$:
+		|| m:fs/hugetlbfs/hugetlbfs.o$:
+		|| m:fs/exportfs/exportfs.o$:
+		|| m:fs/devpts/devpts.o$:
+		|| m:arch/ia64/sn/kernel/xp.o$:
+		|| m:arch/ia64/kernel/gate-syms.o$:
+		|| m:^\.tmp_:
+		|| m:^.*/\.tmp_:
+		|| m:sound/pci/snd-intel8x0.o$:
+		|| m:sound/drivers/mpu401/snd-mpu401-uart.o$:
+		|| m:sound/core/snd-timer.o$:
+		|| m:sound/core/snd-rawmidi.o$:
+		|| m:sound/core/seq/snd-seq-device.o$:
+		|| m:sound/core/seq/snd-seq-midi-event.o$:
+		|| m:sound/core/seq/snd-seq-midi.o$:
+		|| m:sound/core/oss/snd-mixer-oss.o$:
+		|| m:sound/core/snd-rtctimer.o$:
+		|| m:sound/core/seq/snd-seq-dummy.o$:
+		|| m:sound/core/seq/snd-seq-virmidi.o$:
+		|| m:sound/drivers/snd-dummy.o$:
+		|| m:sound/drivers/snd-virmidi.o$:
+		|| m:sound/drivers/snd-serial-u16550.o$:
+		|| m:sound/drivers/snd-mtpav.o$:
+		|| m:sound/drivers/mpu401/snd-mpu401.o$:
+		|| m:init/mounts.o$:
+		|| m:fs/msdos/msdos.o$:
+		|| m:arch/i386/kernel/vsyscall-syms.o$:
+		)
+	) {
+		do_nm($basename, $_);
+	}
+	$_ = $basename;		# File::Find expects $_ untouched (undocumented)
+}
+
+sub do_nm
+{
+	my ($basename, $fullname) = @_;
+	my ($source, $type, $name);
+	if (! -e $basename) {
+		printf STDERR "$basename does not exist\n";
+		return;
+	}
+	if ($fullname !~ /\.o$/) {
+		printf STDERR "$fullname is not an object file\n";
+		return;
+	}
+	$source = $basename;
+	$source =~ s/\.o$//;
+	if (! -e "$source.c" && ! -e "$source.S") {
+		# No obvious source, exclude the object if it is conglomerate
+		if (! open(OBJDUMPDATA, "$objdump $basename|")) {
+			printf STDERR "$objdump $fullname failed $!\n";
+			return;
+		}
+		my $comment;
+		while (<OBJDUMPDATA>) {
+			chomp();
+			if (/^In archive/) {
+				# Archives are always conglomerate
+				$comment = "GCC:GCC:";
+				last;
+			}
+			next if (! /^[ 0-9a-f]{5,} /);
+			$comment .= substr($_, 43);
+		}
+		close(OBJDUMPDATA);
+		if (!defined($comment) || $comment !~ /GCC\:.*GCC\:/m) {
+			printf STDERR "No source file found for $fullname\n";
+		}
+		return;
+	}
+	if (! open(NMDATA, "$nm $basename|")) {
+		printf STDERR "$nm $fullname failed $!\n";
+		return;
+	}
+	my @nmdata;
+	while (<NMDATA>) {
+		chop;
+		($type, $name) = (split(/ +/, $_, 3))[1..2];
+		# Expected types
+		# B weak external reference to data that has been resolved
+		# C global variable, uninitialised
+		# D global variable, initialised
+		# G global variable, initialised, small data section
+		# R global array, initialised
+		# S global variable, uninitialised, small bss
+		# T global label/procedure
+		# U external reference
+		# W weak external reference to text that has been resolved
+		# a assembler equate
+		# b static variable, uninitialised
+		# d static variable, initialised
+		# g static variable, initialised, small data section
+		# r static array, initialised
+		# s static variable, uninitialised, small bss
+		# t static label/procedures
+		# w weak external reference to text that has not been resolved
+		# ? undefined type, used a lot by modules
+		if ($type !~ /^[BCDGRSTUWabdgrstw?]$/) {
+			printf STDERR "nm output for $fullname contains unknown type '$_'\n";
+		}
+		elsif ($name =~ /\./) {
+			# name with '.' is local static
+		}
+		else {
+			$type = 'R' if ($type eq '?');	# binutils replaced ? with R at one point
+			$name =~ s/_R[a-f0-9]{8}$//;	# module versions adds this
+			if ($type =~ /[BCDGRSTW]/ &&
+				$name ne 'init_module' &&
+				$name ne 'cleanup_module' &&
+				$name ne 'Using_Versions' &&
+				$name !~ /^Version_[0-9]+$/ &&
+				$name !~ /^__parm_/ &&
+				$name !~ /^__kstrtab/ &&
+				$name !~ /^__ksymtab/ &&
+				$name !~ /^__exitcall_/ &&
+				$name !~ /^__initcall_/ &&
+				$name !~ /^__kdb_initcall_/ &&
+				$name !~ /^__kdb_exitcall_/ &&
+				$name !~ /^__module_/ &&
+				$name !~ /^__mod_/ &&
+				$name ne '__this_module' &&
+				$name ne 'kernel_version') {
+				if (!exists($def{$name})) {
+					$def{$name} = [];
+				}
+				push(@{$def{$name}}, $fullname);
+			}
+			push(@nmdata, "$type $name");
+			if ($name =~ /^__ksymtab_/) {
+				$name = substr($name, 10);
+				if (!exists($ksymtab{$name})) {
+					$ksymtab{$name} = [];
+				}
+				push(@{$ksymtab{$name}}, $fullname);
+			}
+		}
+	}
+	close(NMDATA);
+	if ($#nmdata < 0) {
+		if (
+			$fullname ne "lib/brlock.o"
+			&& $fullname ne "lib/dec_and_lock.o"
+			&& $fullname ne "fs/xfs/xfs_macros.o"
+			&& $fullname ne "drivers/ide/ide-probe-mini.o"
+			&& $fullname ne "usr/initramfs_data.o"
+			&& $fullname ne "drivers/acpi/executer/exdump.o"
+			&& $fullname ne "drivers/acpi/resources/rsdump.o"
+			&& $fullname ne "drivers/acpi/namespace/nsdumpdv.o"
+			&& $fullname ne "drivers/acpi/namespace/nsdump.o"
+			&& $fullname ne "arch/ia64/sn/kernel/sn2/io.o"
+			&& $fullname ne "arch/ia64/kernel/gate-data.o"
+			&& $fullname ne "drivers/ieee1394/oui.o"
+			&& $fullname ne "security/capability.o"
+			&& $fullname ne "sound/core/wrappers.o"
+			&& $fullname ne "fs/ntfs/sysctl.o"
+		) {
+			printf "No nm data for $fullname\n";
+		}
+		return;
+	}
+	$nmdata{$fullname} = \@nmdata;
+}
+
+sub drop_def
+{
+	my ($object, $name) = @_;
+	my $nmdata = $nmdata{$object};
+	my ($i, $j);
+	for ($i = 0; $i <= $#{$nmdata}; ++$i) {
+		if ($name eq (split(' ', $nmdata->[$i], 2))[1]) {
+			splice(@{$nmdata{$object}}, $i, 1);
+			my $def = $def{$name};
+			for ($j = 0; $j < $#{$def{$name}}; ++$j) {
+				if ($def{$name}[$j] eq $object) {
+					splice(@{$def{$name}}, $j, 1);
+				}
+			}
+			last;
+		}
+	}
+}
+
+sub list_multiply_defined
+{
+	my ($name, $module);
+	foreach $name (keys(%def)) {
+		if ($#{$def{$name}} > 0) {
+			# Special case for cond_syscall
+			if ($#{$def{$name}} == 1 && $name =~ /^sys_/ &&
+			    ($def{$name}[0] eq "kernel/sys.o" ||
+			     $def{$name}[1] eq "kernel/sys.o")) {
+				&drop_def("kernel/sys.o", $name);
+				next;
+			}
+			# Special case for i386 entry code
+			if ($#{$def{$name}} == 1 && $name =~ /^__kernel_/ &&
+			    $def{$name}[0] eq "arch/i386/kernel/vsyscall-int80.o" &&
+			    $def{$name}[1] eq "arch/i386/kernel/vsyscall-sysenter.o") {
+				&drop_def("arch/i386/kernel/vsyscall-sysenter.o", $name);
+				next;
+			}
+			printf "$name is multiply defined in :-\n";
+			foreach $module (@{$def{$name}}) {
+				printf "\t$module\n";
+			}
+		}
+	}
+}
+
+sub resolve_external_references
+{
+	my ($object, $type, $name, $i, $j, $kstrtab, $ksymtab, $export);
+	printf "\n";
+	foreach $object (keys(%nmdata)) {
+		my $nmdata = $nmdata{$object};
+		for ($i = 0; $i <= $#{$nmdata}; ++$i) {
+			($type, $name) = split(' ', $nmdata->[$i], 2);
+			if ($type eq "U" || $type eq "w") {
+				if (exists($def{$name}) || exists($ksymtab{$name})) {
+					# add the owning object to the nmdata
+					$nmdata->[$i] = "$type $name $object";
+					# only count as a reference if it is not EXPORT_...
+					$kstrtab = "R __kstrtab_$name";
+					$ksymtab = "R __ksymtab_$name";
+					$export = 0;
+					for ($j = 0; $j <= $#{$nmdata}; ++$j) {
+						if ($nmdata->[$j] eq $kstrtab ||
+						    $nmdata->[$j] eq $ksymtab) {
+							$export = 1;
+							last;
+						}
+					}
+					if ($export) {
+						$export{$name} = "";
+					}
+					else {
+						$ref{$name} = ""
+					}
+				}
+				elsif (    $name ne "mod_use_count_"
+					&& $name ne "__initramfs_end"
+					&& $name ne "__initramfs_start"
+					&& $name ne "_einittext"
+					&& $name ne "_sinittext"
+					&& $name ne "kallsyms_names"
+					&& $name ne "kallsyms_num_syms"
+					&& $name ne "kallsyms_addresses"
+					&& $name ne "__this_module"
+					&& $name ne "_etext"
+					&& $name ne "_edata"
+					&& $name ne "_end"
+					&& $name ne "__bss_start"
+					&& $name ne "_text"
+					&& $name ne "_stext"
+					&& $name ne "__gp"
+					&& $name ne "ia64_unw_start"
+					&& $name ne "ia64_unw_end"
+					&& $name ne "__setup_start"
+					&& $name ne "__setup_end"
+					&& $name ne "__init_begin"
+					&& $name ne "__init_end"
+					&& $name ne "__bss_stop"
+					&& $name ne "__nosave_begin"
+					&& $name ne "__nosave_end"
+					&& $name ne "pg0"
+					&& $name ne "__module_text_address"
+					&& $name !~ /^__sched_text_/
+					&& $name !~ /^__start_/
+					&& $name !~ /^__end_/
+					&& $name !~ /^__stop_/
+					&& $name !~ /^__scheduling_functions_.*_here/
+					&& $name !~ /^__.*initcall_/
+					&& $name !~ /^__.*per_cpu_start/
+					&& $name !~ /^__.*per_cpu_end/
+					&& $name !~ /^__alt_instructions/
+				) {
+
+					printf "Cannot resolve ";
+					printf "weak " if ($type eq "w");
+					printf "reference to $name from $object\n";
+				}
+			}
+		}
+	}
+}
+
+sub list_extra_externals
+{
+	my %noref = ();
+	my ($name, @module, $module, $export);
+	foreach $name (keys(%def)) {
+		if (! exists($ref{$name})) {
+			@module = @{$def{$name}};
+			foreach $module (@module) {
+				if (! exists($noref{$module})) {
+					$noref{$module} = [];
+				}
+				push(@{$noref{$module}}, $name);
+			}
+		}
+	}
+	if (%noref) {
+		printf "\nExternally defined symbols with no external references\n";
+		foreach $module (sort(keys(%noref))) {
+			printf "  $module\n";
+			foreach (sort(@{$noref{$module}})) {
+				if (exists($export{$_})) {
+					$export = " (export only)";
+				}
+				else {
+					$export = "";
+				}
+				printf "    $_$export\n";
+			}
+		}
+	}
+}
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