localmodconfig: Read in orig config file to avoid extra processing

Read in the entire config file. If there's a config that we depend on
that happens to be in the core set (not a module) then we do not need
to process it as a module.

Currently, we follow the entire depend and selects even if they
are enabled as core and not modules. By checking to make sure that we
only look at modules we can drop the count a little.

From one of my tests, localmodconfig went from taking 3095 set modules
down to 356 before this patch, and down to 290 modules after the change.

Tested-by: John David Yost <johnyost@ptd.net> # AlleyTrotter
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

scripts/kconfig/streamline_config.pl

@@ -113,6 +113,10 @@ sub find_config {
 
 find_config;
 
+# Read in the entire config file into config_file
+my @config_file = <CIN>;
+close CIN;
+
 # Parse options
 my $localmodconfig = 0;
 my $localyesconfig = 0;
@@ -392,7 +396,20 @@ foreach my $module (keys(%modules)) {
     }
 }
 
+# Read the current config, and see what is enabled. We want to
+# ignore configs that we would not enable anyway.
+
+my %orig_configs;
 my $valid = "A-Za-z_0-9";
+
+foreach my $line (@config_file) {
+    $_ = $line;
+
+    if (/(CONFIG_[$valid]*)=(m|y)/) {
+	$orig_configs{$1} = $2;
+    }
+}
+
 my $repeat = 1;
 
 #
@@ -414,6 +431,11 @@ sub parse_config_dep_select
 
 	    $p =~ s/^[^$valid]*[$valid]+//;
 
+	    # We only need to process if the depend config is a module
+	    if (!defined($orig_configs{$conf}) || !$orig_configs{conf} eq "m") {
+		next;
+	    }
+
 	    if (!defined($configs{$conf})) {
 		# We must make sure that this config has its
 		# dependencies met.
@@ -450,7 +472,8 @@ my %setconfigs;
 
 # Finally, read the .config file and turn off any module enabled that
 # we could not find a reason to keep enabled.
-while(<CIN>) {
+foreach my $line (@config_file) {
+    $_ = $line;
 
     if (/CONFIG_IKCONFIG/) {
 	if (/# CONFIG_IKCONFIG is not set/) {
@@ -478,7 +501,6 @@ while(<CIN>) {
     }
     print;
 }
-close(CIN);
 
 # Integrity check, make sure all modules that we want enabled do
 # indeed have their configs set.