Add new script, analyze_build.pl, that analyzes the Makefile tree

From: Trent Piepho <xyzzy@speakeasy.org>

This script will read a Linux Kernel style Makefile tree and produce an
overview of the build process.

It produces three lists which show to associations of:
1. Kconfig variables to kernel module(s) built
2. Kernel modules to source file(s) that make them
3. Kconfig variables to source file(s) built

It can also check the Makefiles for various errors and warnings.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>

1 files changed, 179 insertions, 0 deletions

diff --git a/v4l/scripts/analyze_build.pl b/v4l/scripts/analyze_build.pl
new file mode 100755
index 000000000..945377fa4
--- /dev/null
+++ b/v4l/scripts/analyze_build.pl
@@ -0,0 +1,179 @@
+#!/usr/bin/perl
+
+# Copyright (C) 2006 Trent Piepho <xyzzy@speakeasy.org>
+# Scans a tree of Linux Kernel style Makefiles, and builds lists of what
+# builds what.
+# Outputs three lists:
+# 1.  Kconfig variables associated with the kernel module(s) they turn on
+# 2.  Kernel modules associated with their source file(s)
+# 3.  Kconfig variables associated with all the source file(s) they turn on
+#
+# Optional options:
+#   Prefix relative to source tree root to start scanning in.  This
+#   will be stripped from the beginnings of all filenames printed out.
+#     Default is 'linux/drivers/media'
+#   Root of source tree
+#     Default is to use 'hg root' command and if that fails the cwd
+#
+# Most usefull with grep, for example
+# List of modules and source files used by DVB_BUDGET_AV
+# deps.pl | grep DVB_BUDGET_AV
+#
+# Kconfig variable and kernel module that use dvb-usb-init.c
+# deps.pl | grep dvb-usb-init.c
+#
+# Kconfig variable and source files that make dvb-core.ko
+# deps.pl | grep dvb-core.ko
+#
+# Also has some ability to check Makefiles for errors
+use strict;
+use FileHandle;
+
+# Print out some extra checks of Makefile correctness
+my $check = 0;
+
+# Directory to start in.  Will be stripped from all filenames printed out.
+my $prefix = 'linux/drivers/media/';
+
+# Root of source tree
+my $root;
+
+# List of Makefile's opened
+my %makefiles = ();
+
+# For each Kconfig variable, a list of modules it builds
+my %config = ();
+
+# For each module that is made up of multiple source files, list of sources
+my %multi = ();
+
+sub open_makefile($) {
+    my $file = shift;
+
+    # only open a given Makefile once
+    return if exists $makefiles{$file};
+    $makefiles{$file} = 1;
+
+    $file =~ m|^(.*)/[^/]*$|;
+    my $dir = $1;
+
+#    print STDERR "opening $root$file (dir=$dir)\n";
+    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$/) {
+		    push @{$config{$var}}, "$dir/$1";
+		} else {
+		    print STDERR "Confused by target '$_' in $file:$.\n";
+		}
+	    }
+	    next;
+	}
+	if (/(\S+)-objs\s*([:+]?)=\s*(\S.*?)\s*$/) {
+	    print STDERR "Should use ':=' in $file:$.\n$_\n" if ($check && $2 ne ':');
+	    my @files = split(/\s+/, $3);
+	    map { s|^(.*)\.o$|$dir/\1| } @files;
+	    $multi{"$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);
+    }
+}
+
+if ($#ARGV >= 0) {
+    $prefix = $ARGV[0];
+    $prefix .= '/' unless ($prefix =~ m|/$|);
+}
+
+# Find root of source tree: command line, then Hg command, lastly cwd
+if ($#ARGV >= 1) {
+    $root = $ARGV[1];
+    $root .= '/' unless ($root =~ m|/$|);
+} else {
+    $root = `hg root 2>/dev/null`;
+    if($? == 0) {
+	chomp $root;
+	$root .= '/';
+    } else {
+	$root = '';
+    }
+}
+print "# Using source tree root '$root'\n" if ($root ne '');
+
+open_makefile($prefix."Makefile");
+
+print "# Kconfig variable = kernel modules built\n";
+foreach my $var (keys %config) {
+    my @list = @{$config{$var}};
+    map { s/^$prefix(.*)$/\1.ko/ } @list;
+    printf "%-22s= %s\n", $var, join(' ', @list);
+}
+
+print "\n# kernel module = source files\n";
+my %modules = ();
+foreach my $mods (values %config) {
+    $modules{$_} = 1 foreach @$mods;
+}
+foreach (keys %modules) {
+    /$prefix(.*)$/;
+    printf "%-30s = ", "$1.ko";
+    if (exists $multi{$_}) {
+	my @list =  @{$multi{$_}};
+	map { s/^$prefix(.*)$/\1.c/ } @list;
+	print join(' ', @list), "\n";
+    } else {
+	print "$1.c\n";
+    }
+}
+
+print "\n# Kconfig varible = source files\n";
+while (my ($var, $list) = each %config) {
+    my @outlist = ();
+    foreach (@$list) {
+	if (exists $multi{$_}) {
+	    push @outlist, @{$multi{$_}};
+	} else {
+	    push @outlist, $_;
+	}
+    }
+    map { s/^$prefix(.*)$/\1.c/ } @outlist;
+    printf "%-22s= %s\n", $var, join(' ', @outlist);
+}
+
+exit;