lint: Add Kconfig / Kconfig symbol lint tool

This is a tool to help identify issues in coreboot's Kconfig structure
and in how the Kconfig symbols are used in the coreboot codebase.

It identifies a number of issues:
- #ifdef used on Kconfig symbol of type bool, hex, or int.  These are
always defined.
- #define CONFIG_ in the coreboot code - these should be reserved
for Kconfig symbols.
- Redefinition of Kconfig symbols in the code.
- Use of IS_ENABLED() on non-bool kconfig symbols.
- Use of IS_ENABLED() on values that are not kconfig symbols.
- Attempts to find default values that will not set anything
because of earlier default settings.  This needs to be expanded
significantly.
- Kconfig expressions using symbols which are not defined.
- Kconfig symbols that are defined but not used anywhere in the
Kconfig structure or coreboot code.
- Kconfig keywords used incorrectly.
- Whitespace issues
- Kconfig 'source' keyword issues
-- sourcing non-existant directories
-- sourcing Kconfig files multiple times
-- sourcing non-existent files
-- Kconfig files in the codebase that are never sourced

Additionally, it can be used to help debug the Kconfig tree
by putting all the files together into a single file with
their source locations listed.

Run from the coreboot directory:
util/lint/kconfig_lint

Change-Id: Ia53b366461698d949f17502e99265c1f3f3b1443
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: http://review.coreboot.org/12088
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

1 files changed, 1153 insertions, 0 deletions

diff --git a/util/lint/kconfig_lint b/util/lint/kconfig_lint
new file mode 100755
index 0000000000..2b871572c1
--- /dev/null
+++ b/util/lint/kconfig_lint
@@ -0,0 +1,1153 @@
+#!/usr/bin/perl
+
+#
+# This file is part of the coreboot project.
+#
+# Copyright (C) 2015 Martin L Roth <gaumless@gmail.com>
+# Copyright (C) 2015 Google, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.
+#
+
+package kconfig_lint;
+
+use strict;
+use warnings;
+use English qw( -no_match_vars );
+use File::Find;
+use Getopt::Long;
+use Getopt::Std;
+
+my $suppress_error_output = 0;      # flag to prevent warning and error text
+my $print_full_output    = 0;      # flag to print wholeconfig output
+my $output_file          = "-";    # filename of output - set stdout by default
+my $dont_use_git_grep    = 0;
+
+#globals
+my $top_dir       = ".";           # Directory where Kconfig is run
+my $root_dir      = "src";         # Directory of the top level Kconfig file
+my $errors_found = 0;              # count of warnings and errors
+my $exclude_dirs  = '--exclude-dir="build" --exclude-dir="coreboot-builds" --exclude-dir="payloads" --exclude-dir="configs" --exclude-dir="util"';  # directories to exclude when searching for used symbols - NOT USED FOR GIT GREP (TODO)
+my @exclude_files = ('\.txt$', '\.tex$', 'config', '\.tags'); #files to exclude when looking for symbols
+my $config_file   = "";            # name of config file to load symbol values from.
+my @wholeconfig;                   # document the entire kconfig structure
+my %loaded_files;                  # list of each Kconfig file loaded
+my %symbols;                       # main structure of all symbols declared
+my %referenced_symbols;            # list of symbols referenced by expressions or select statements
+my %used_symbols;                  # structure of symbols used in the tree, and where they're found
+my @collected_symbols;             #
+
+Main();
+
+#-------------------------------------------------------------------------------
+# Main
+#
+# Start by loading and parsing the top level Kconfig, this pulls in the other
+# files.  Parsing the tree creates several arrays and hashes that can be used
+# to check for errors
+#-------------------------------------------------------------------------------
+sub Main {
+
+    check_arguments();
+    open( STDOUT, "> $output_file" ) or die "Can't open $output_file for output: $!\n";
+
+    if (defined $top_dir) {
+        chdir $top_dir  or die "Error: can't cd to $top_dir\n";
+    }
+
+    die "Error: $top_dir/$root_dir does not exist.\n" unless (-d $root_dir);
+
+    #load the Kconfig tree, checking what we can and building up all the hash tables
+    build_and_parse_kconfig_tree("$root_dir/Kconfig");
+
+    #run checks based on the data that was found
+    find( \&check_if_file_referenced, $root_dir );
+
+    load_config($config_file) if ($config_file);
+
+    check_defaults();
+    check_referenced_symbols();
+
+    collect_used_symbols();
+    check_used_symbols();
+    check_for_ifdef();
+    check_for_def();
+    check_is_enabled();
+
+    print_wholeconfig();
+
+    exit($errors_found);
+}
+
+#-------------------------------------------------------------------------------
+# check_for_ifdef - Look for instances of #ifdef CONFIG_[symbol_name] and
+# #if defined(CONFIG_[symbol_name]).
+#
+# #ifdef symbol is valid for strings, but bool, hex, and INT are always defined.
+# #if defined(symbol) && symbol is also a valid construct.
+#-------------------------------------------------------------------------------
+sub check_for_ifdef {
+    my @ifdef_symbols = @collected_symbols;
+
+    #look for #ifdef SYMBOL
+    while ( my $line = shift @ifdef_symbols ) {
+        if ( $line =~ /^([^:]+):(\d+):\s*#\s*ifn?def\s+CONFIG_(\w+)/ ) {
+            my $file = $1;
+            my $lineno = $2;
+            my $symbol = $3;
+
+            if ((exists $symbols{$symbol}) && ($symbols{$symbol}{type} ne "string")) {
+                unless ($suppress_error_output) {
+                    print "#!!!!! Warning: #ifdef 'CONFIG_$symbol' used in $file at line $lineno.  Symbols of type '$symbols{$symbol}{type}' are always defined.\n";
+                }
+                $errors_found++;
+            }
+        }
+    }
+
+    # look for (#if) defined SYMBOL
+    @ifdef_symbols = @collected_symbols;
+    while ( my $line = shift @ifdef_symbols ) {
+        if ( $line =~ /^([^:]+):(\d+):.+defined\s*\(\s*CONFIG_(\w+)/ ) {
+            my $file = $1;
+            my $lineno = $2;
+            my $symbol = $3;
+
+            #ignore '#if defined(symbol) && symbol' type statements
+            next if ( $line =~ /^([^:]+):(\d+):.+defined\s*\(\s*CONFIG_$symbol.*(&&|\|\|)\s*!?\s*\(?\s*CONFIG_$symbol/ );
+
+            if ((exists $symbols{$symbol}) && ($symbols{$symbol}{type} ne "string")) {
+                unless ($suppress_error_output) {
+                    print "#!!!!! Warning: defined 'CONFIG_$symbol' used in $file at line $lineno.  Symbols of type '$symbols{$symbol}{type}' are always defined.\n";
+                }
+                $errors_found++;
+            }
+        }
+    }
+}
+
+#-------------------------------------------------------------------------------
+# check_for_def - Look for instances of #define CONFIG_[symbol_name]
+#
+# Symbols should not be redefined outside of Kconfig, and #defines should not
+# look like symbols
+#-------------------------------------------------------------------------------
+sub check_for_def {
+    my @def_symbols = @collected_symbols;
+
+    #look for #ifdef SYMBOL
+    while ( my $line = shift @def_symbols ) {
+        if ( $line =~ /^([^:]+):(\d+):\s*#\s*define\s+CONFIG_(\w+)/ ) {
+            my $file = $1;
+            my $lineno = $2;
+            my $symbol = $3;
+
+            if ((exists $symbols{$symbol})) {
+                unless ($suppress_error_output) {
+                    print "#!!!!! Warning: #define of symbol 'CONFIG_$symbol' used in $file at line $lineno.\n";
+                }
+                $errors_found++;
+            } else {
+                unless ($suppress_error_output) {
+                    print "#!!!!! Warning: #define 'CONFIG_$symbol' used in $file at line $lineno.  Other #defines should not look like Kconfig symbols.\n";
+                }
+                $errors_found++;
+	    }
+        }
+    }
+}
+
+#-------------------------------------------------------------------------------
+# check_is_enabled - The IS_ENABLED() macro is only valid for symbols of type
+# bool. It would probably work on type hex or int if the value was 0 or 1, but
+# this seems like a bad plan.  Using it on strings is dead out.
+#-------------------------------------------------------------------------------
+sub check_is_enabled {
+    my @is_enabled_symbols = `grep -Grn 'IS_ENABLED\\s*(\\s*CONFIG_' -- "$root_dir"`;
+
+    #sort through symbols found by grep and store them in a hash for easy access
+    while ( my $line = shift @is_enabled_symbols ) {
+        if ( $line =~ /^([^:]+):(\d+):.+IS_ENABLED\s*\(\s*CONFIG_(\w+)/ ) {
+            my $file = $1;
+            my $lineno = $2;
+            my $symbol = $3;
+
+            #make sure that
+            if (exists $symbols{$symbol}) {
+                if ($symbols{$symbol}{type} ne "bool") {
+                    unless ($suppress_error_output) {
+                        print "#!!!!! Warning: IS_ENABLED(CONFIG_$symbol) used in $file at line $lineno.  IS_ENABLED is only valid for type 'bool', not '$symbols{$symbol}{type}'.\n";
+                    }
+                    $errors_found++;
+                }
+            } else {
+                print "#!!!!! Warning: IS_ENABLED() used on unknown value CONFIG_$symbol in $file at line $lineno.\n";
+            }
+        } else {
+            print "# uninterpreted IS_ENABLED line: $line\n";
+        }
+    }
+}
+
+#-------------------------------------------------------------------------------
+# check_defaults - Look for defaults that come after a default with no
+# dependencies.
+#
+# TODO - check for defaults with the same dependencies
+#-------------------------------------------------------------------------------
+sub check_defaults {
+
+    # loop through each defined symbol
+    foreach my $sym ( sort ( keys %symbols ) ) {
+        my $default_set      = 0;
+        my $default_filename = "";
+        my $default_line_no  = "";
+
+        #loop through each instance of that symbol
+        for ( my $sym_num = 0 ; $sym_num <= $symbols{$sym}{count} ; $sym_num++ ) {
+
+            #loop through any defaults for that instance of that symbol, if there are any
+            next unless ( exists $symbols{$sym}{$sym_num}{default_max} );
+            for ( my $def_num = 0 ; $def_num <= $symbols{$sym}{$sym_num}{default_max} ; $def_num++ ) {
+
+                #if a default is already set, display an error
+                if ($default_set) {
+                    my $filename = $symbols{$sym}{$sym_num}{file};
+                    my $line_no  = $symbols{$sym}{$sym_num}{default}{$def_num}{default_line_no};
+                    unless ($suppress_error_output) {
+                        print "#!!!!! Error: Default for '$sym' referenced in $filename at line $line_no will never be set - overridden by default set in $default_filename at line $default_line_no \n";
+                    }
+                    $errors_found++;
+                }
+                else {
+                    #if no default is set, see if this is a default with no dependencies
+                    unless ( ( exists $symbols{$sym}{$sym_num}{default}{$def_num}{default_depends_on} )
+                        || ( exists $symbols{$sym}{$sym_num}{max_dependency} ) )
+                    {
+                        $default_set      = 1;
+                        $default_filename = $symbols{$sym}{$sym_num}{file};
+                        $default_line_no  = $symbols{$sym}{$sym_num}{default}{$def_num}{default_line_no};
+                    }
+                }
+            }
+        }
+    }
+}
+
+#-------------------------------------------------------------------------------
+# check_referenced_symbols - Make sure the symbols referenced by expressions and
+# select statements are actually valid symbols.
+#-------------------------------------------------------------------------------
+sub check_referenced_symbols {
+
+    #loop through symbols found in expressions and used by 'select' keywords
+    foreach my $key ( sort ( keys %referenced_symbols ) ) {
+
+        #make sure the symbol was defined by a 'config' or 'choice' keyword
+        next if ( exists $symbols{$key} );
+
+            #loop through each instance of the symbol to print out all of the invalid references
+            for ( my $i = 0 ; $i <= $referenced_symbols{$key}{count} ; $i++ ) {
+                my $filename = $referenced_symbols{$key}{$i}{filename};
+                my $line_no  = $referenced_symbols{$key}{$i}{line_no};
+                unless ($suppress_error_output) {
+                    print "#!!!!! Error: Undefined Symbol '$key' used in $filename at line $line_no.\n";
+                }
+                $errors_found++;
+        }
+    }
+}
+
+#-------------------------------------------------------------------------------
+#-------------------------------------------------------------------------------
+sub collect_used_symbols {
+    # find all references to CONFIG_ statements in the tree
+
+    if ($dont_use_git_grep) {
+        @collected_symbols = `grep -Irn $exclude_dirs -- "CONFIG_"`;
+    } else {
+        @collected_symbols = `git grep -In -- "CONFIG_"`;
+    }
+
+    my @used_symbols = @collected_symbols;
+
+    #sort through symbols found by grep and store them in a hash for easy access
+    while ( my $line = shift @used_symbols ) {
+        while ( $line =~ /[^A-Za-z0-9_]CONFIG_([A-Za-z0-9_]+)/g ) {
+            my $symbol = $1;
+            my $filename = "";
+            if ($line =~ /^([^:]+):/) {
+                $filename = $1;
+            }
+
+            my $skip = 0;
+            foreach my $exfile ( @exclude_files)  {
+                $skip = ($filename =~ /$exfile/);
+                last if $skip;
+            }
+            last if $skip;
+
+            if (exists $used_symbols{$symbol}{count}) {
+                $used_symbols{$symbol}{count}++;
+            } else {
+                 $used_symbols{$symbol}{count} = 0;
+            }
+            $used_symbols{$symbol}{"num_$used_symbols{$symbol}{count}"} = $filename;
+         }
+    }
+}
+
+#-------------------------------------------------------------------------------
+# check_used_symbols - Checks to see whether or not the created symbols are
+# actually used.
+#-------------------------------------------------------------------------------
+sub check_used_symbols {
+    # loop through all defined symbols and see if they're used anywhere
+    foreach my $key ( sort ( keys %symbols ) ) {
+
+        #see if they're used internal to Kconfig
+        next if ( exists $referenced_symbols{$key} );
+
+        #see if they're used externally
+        next if exists $used_symbols{$key};
+
+        #loop through the definitions to print out all the places the symbol is defined.
+        for ( my $i = 0 ; $i <= $symbols{$key}{count} ; $i++ ) {
+            my $filename = $symbols{$key}{$i}{file};
+            my $line_no  = $symbols{$key}{$i}{line_no};
+            unless ($suppress_error_output) {
+                print "#!!!!! Warning: Unused symbol '$key' referenced in $filename at line $line_no.\n";
+            }
+            $errors_found++;
+        }
+    }
+}
+
+#-------------------------------------------------------------------------------
+# build_and_parse_kconfig_tree
+#-------------------------------------------------------------------------------
+#load the initial file and start parsing it
+sub build_and_parse_kconfig_tree {
+    my ($top_level_kconfig) = @_;
+    my @config_to_parse;
+    my @parseline;
+    my $inside_help   = 0;     # set to line number of 'help' keyword if this line is inside a help block
+    my @inside_if     = ();    # stack of if dependencies
+    my $inside_config = "";    # set to symbol name of the config section
+    my @inside_menu   = ();    # stack of menu names
+    my $inside_choice = "";
+    my $configs_inside_choice;
+
+    #start the tree off by loading the top level kconfig
+    @config_to_parse = load_kconfig_file( $top_level_kconfig, "", 0, 0, "", 0 );
+
+
+    while ( ( @parseline = shift(@config_to_parse) ) && ( exists $parseline[0]{text} ) ) {
+        my $line     = $parseline[0]{text};
+        my $filename = $parseline[0]{filename};
+        my $line_no  = $parseline[0]{file_line_no};
+
+        #handle help - help text: "help" or "---help---"
+        $inside_help = handle_help( $line, $inside_help, $inside_config, $inside_choice, $filename, $line_no );
+        $parseline[0]{inside_help} = $inside_help;
+
+        #look for basic issues in the line, strip crlf
+        $line = simple_line_checks( $line, $filename, $line_no );
+
+        #strip comments
+        $line =~ s/\s*#.*$//;
+
+        #don't parse any more if we're inside a help block
+        if ($inside_help) {
+            #do nothing
+        }
+
+        #handle config
+        elsif ( $line =~ /^\s*config/ ) {
+            $line =~ /^\s*config\s+([^"\s]+)\s*(?>#.*)?$/;
+            my $symbol = $1;
+            $inside_config = $symbol;
+            if ($inside_choice) {
+                $configs_inside_choice++;
+            }
+            add_symbol( $symbol, \@inside_menu, $filename, $line_no, \@inside_if );
+        }
+
+        #bool|hex|int|string|tristate <expr> [if <expr>]
+        elsif ( $line =~ /^\s*(bool|string|hex|int|tristate)/ ) {
+            $line =~ /^\s*(bool|string|hex|int|tristate)\s*(.*)/;
+            my ( $type, $prompt ) = ( $1, $2 );
+            handle_type( $type, $inside_config, $filename, $line_no );
+            handle_prompt( $prompt, $type, \@inside_menu, $inside_config, $inside_choice, $filename, $line_no );
+        }
+
+        # def_bool|def_tristate <expr> [if <expr>]
+        elsif ( $line =~ /^\s*(def_bool|def_tristate)/ ) {
+            $line =~ /^\s*(def_bool|def_tristate)\s+(.*)/;
+            my ( $orgtype, $default ) = ( $1, $2 );
+            ( my $type = $orgtype ) =~ s/def_//;
+            handle_type( $type, $inside_config, $filename, $line_no );
+            handle_default( $default, $orgtype, $inside_config, $inside_choice, $filename, $line_no );
+        }
+
+        #prompt <prompt> [if <expr>]
+        elsif ( $line =~ /^\s*prompt/ ) {
+            $line =~ /^\s*prompt\s+(.+)/;
+            handle_prompt( $1, "prompt", \@inside_menu, $inside_config, $inside_choice, $filename, $line_no );
+        }
+
+        # default <expr> [if <expr>]
+        elsif ( $line =~ /^\s*default/ ) {
+            $line =~ /^\s*default\s+(.*)/;
+            my $default = $1;
+            handle_default( $default, "default", $inside_config, $inside_choice, $filename, $line_no );
+        }
+
+        # depends on <expr>
+        elsif ( $line =~ /^\s*depends\s+on/ ) {
+            $line =~ /^\s*depends\s+on\s+(.*)$/;
+            my $expr = $1;
+            handle_depends( $expr, $inside_config, $inside_choice, $filename, $line_no );
+            handle_expressions( $expr, $inside_config, $filename, $line_no );
+        }
+
+        # comment <prompt>
+        elsif ( $line =~ /^\s*comment/ ) {
+            $inside_config = "";
+        }
+
+        # choice [symbol]
+        elsif ( $line =~ /^\s*choice/ ) {
+            if ( $line =~ /^\s*choice\s*([A-Za-z0-9_]+)$/ ) {
+                my $symbol = $1;
+                add_symbol( $symbol, \@inside_menu, $filename, $line_no, \@inside_if );
+                handle_type( "bool", $symbol, $filename, $line_no );
+            }
+            $inside_config         = "";
+            $inside_choice         = "$filename $line_no";
+            $configs_inside_choice = 0;
+        }
+
+        # endchoice
+        elsif ( $line =~ /^\s*endchoice/ ) {
+            $inside_config = "";
+            if ( !$inside_choice ) {
+                unless ($suppress_error_output) {
+                    print "#!!!!! Warning: 'endchoice' keyword not within a choice block in $filename at line $line_no.\n";
+                }
+                $errors_found++;
+            }
+
+            $inside_choice = "";
+            if ( $configs_inside_choice == 0 ) {
+                unless ($suppress_error_output) {
+                    print "#!!!!! Warning: choice block has no symbols in $filename at line $line_no.\n";
+                }
+                $errors_found++;
+            }
+            $configs_inside_choice = 0;
+        }
+
+        # [optional]
+        elsif ( $line =~ /^\s*optional/ ) {
+            if ($inside_config) {
+                unless ($suppress_error_output) {
+                    print "#!!!!! Error: Keyword 'optional' appears inside config for  '$inside_config' in $filename at line $line_no.  This is not valid.\n";
+                }
+                $errors_found++;
+            }
+            if ( !$inside_choice ) {
+                unless ($suppress_error_output) {
+                    print "#!!!!! Error: Keyword 'optional' appears outside of a choice block in $filename at line $line_no.  This is not valid.\n";
+                }
+                $errors_found++;
+            }
+        }
+
+        # mainmenu <prompt>
+        elsif ( $line =~ /^\s*mainmenu/ ) {
+            $inside_config = "";
+        }
+
+        # menu <prompt>
+        elsif ( $line =~ /^\s*menu/ ) {
+            $line =~ /^\s*menu\s+(.*)/;
+            my $menu = $1;
+            if ( $menu =~ /^\s*"([^"]*)"\s*$/ ) {
+                $menu = $1;
+            }
+
+            $inside_config = "";
+            $inside_choice = "";
+            push( @inside_menu, $menu );
+        }
+
+        # endmenu
+        elsif ( $line =~ /^\s*endmenu/ ) {
+            $inside_config = "";
+            $inside_choice = "";
+            pop @inside_menu;
+        }
+
+        # "if" <expr>
+        elsif ( $line =~ /^\s*if/ ) {
+            $inside_config = "";
+            $line =~ /^\s*if\s+(.*)$/;
+            my $expr = $1;
+            push( @inside_if, $expr );
+            handle_expressions( $expr, $inside_config, $filename, $line_no );
+
+        }
+
+        # endif
+        elsif ( $line =~ /^\s*endif/ ) {
+            $inside_config = "";
+            pop(@inside_if);
+        }
+
+        #range <symbol> <symbol> [if <expr>]
+        elsif ( $line =~ /^\s*range/ ) {
+            $line =~ /^\s*range\s+(\S+)\s+(.*)$/;
+            handle_range( $1, $2, $inside_config, $filename, $line_no );
+        }
+
+        # select <symbol> [if <expr>]
+        elsif ( $line =~ /^\s*select/ ) {
+            unless ($inside_config) {
+                unless ($suppress_error_output) {
+                    print "#!!!!! Error: Keyword 'select' appears outside of config in $filename at line $line_no.  This is not valid.\n";
+                }
+                $errors_found++;
+            }
+
+            if ( $line =~ /^\s*select\s+(.*)$/ ) {
+                $line = $1;
+                my $expression;
+                ( $line, $expression ) = handle_if_line( $line, $inside_config, $filename, $line_no );
+                if ($line) {
+                    add_referenced_symbol( $line, $filename, $line_no );
+                }
+            }
+        }
+
+        # source <prompt>
+        elsif ( $line =~ /^\s*source\s+"?([^"\s]+)"?\s*(?>#.*)?$/ ) {
+            my @newfile = load_kconfig_file( $1, $filename, $line_no, 0, $filename, $line_no );
+            unshift( @config_to_parse, @newfile );
+            $parseline[0]{text} = "# '$line'\n";
+        }
+        elsif (
+            ( $line =~ /^\s*#/ ) ||    #comments
+            ( $line =~ /^\s*$/ )       #blank lines
+          )
+        {
+            # do nothing
+        }
+        else {
+            unless ($suppress_error_output) {
+                print "### $line  ($filename line $line_no unrecognized)\n";
+            }
+            $errors_found++;
+        }
+
+        push @wholeconfig, @parseline;
+    }
+}
+
+#-------------------------------------------------------------------------------
+#-------------------------------------------------------------------------------
+sub handle_depends {
+    my ( $expr, $inside_config, $inside_choice, $filename, $line_no ) = @_;
+
+    if ($inside_config) {
+        my $sym_num = $symbols{$inside_config}{count};
+        if ( exists $symbols{$inside_config}{$sym_num}{max_dependency} ) {
+            $symbols{$inside_config}{$sym_num}{max_dependency}++;
+        }
+        else {
+            $symbols{$inside_config}{$sym_num}{max_dependency} = 0;
+        }
+
+        my $dep_num = $symbols{$inside_config}{$sym_num}{max_dependency};
+        $symbols{$inside_config}{$sym_num}{dependency}{$dep_num} = $expr;
+    }
+}
+
+#-------------------------------------------------------------------------------
+#-------------------------------------------------------------------------------
+sub add_symbol {
+    my ( $symbol, $menu_array_ref, $filename, $line_no, $ifref ) = @_;
+    my @inside_if = @{$ifref};
+
+    #initialize the symbol or increment the use count.
+    if (( !exists $symbols{$symbol}) || ( !exists $symbols{$symbol}{count} )) {
+        $symbols{$symbol}{count} = 0;
+    }
+    else {
+        $symbols{$symbol}{count}++;
+    }
+
+    # add the location of this instance
+    my $symcount = $symbols{$symbol}{count};
+    $symbols{$symbol}{$symcount}{file}    = $filename;
+    $symbols{$symbol}{$symcount}{line_no} = $line_no;
+
+    #Add the menu structure
+    if ( defined @$menu_array_ref[0] ) {
+        $symbols{$symbol}{$symcount}{menu} = $menu_array_ref;
+    }
+
+    #Add any 'if' statements that the symbol is inside as dependencies
+    if (@inside_if) {
+        my $dep_num = 0;
+        for my $dependency (@inside_if) {
+            $symbols{$symbol}{$symcount}{dependency}{$dep_num} = $dependency;
+            $symbols{$symbol}{$symcount}{max_dependency} = $dep_num;
+            $dep_num++;
+        }
+    }
+}
+
+#-------------------------------------------------------------------------------
+# handle range
+#-------------------------------------------------------------------------------
+sub handle_range {
+    my ( $range1, $range2, $inside_config, $filename, $line_no ) = @_;
+
+    my $expression;
+    ( $range2, $expression ) = handle_if_line( $range2, $inside_config, $filename, $line_no );
+
+    $range1 =~ /^\s*(?:0x)?([A-Fa-f0-9]+)\s*$/;
+    my $checkrange1 = $1;
+    $range2 =~ /^\s*(?:0x)?([A-Fa-f0-9]+)\s*$/;
+    my $checkrange2 = $1;
+
+    if ( $checkrange1 && $checkrange2 && ( hex($checkrange1) > hex($checkrange2) ) ) {
+        unless ($suppress_error_output) {
+            print "#!!!!! Error: Range entry in $filename line $line_no value 1 ($range1) is greater than value 2 ($range2).\n";
+        }
+        $errors_found++;
+
+    }
+
+    if ($inside_config) {
+        if ( exists( $symbols{$inside_config}{range1} ) ) {
+            if ( ( $symbols{$inside_config}{range1} != $range1 ) || ( $symbols{$inside_config}{range2} != $range2 ) ) {
+                unless ($suppress_error_output) {
+                    print "#!!!!! Note: Config '$inside_config' range entry $range1 $range2 at $filename line $line_no does";
+                    print " not match the previously defined range $symbols{$inside_config}{range1} $symbols{$inside_config}{range2}";
+                    print " defined in $symbols{$inside_config}{range_file} on line";
+                    print " $symbols{$inside_config}{range_line_no}.\n";
+                }
+            }
+        }
+        else {
+            $symbols{$inside_config}{range1}        = $range1;
+            $symbols{$inside_config}{range2}        = $range2;
+            $symbols{$inside_config}{range_file}    = $filename;
+            $symbols{$inside_config}{range_line_no} = $line_no;
+        }
+    }
+    else {
+        unless ($suppress_error_output) {
+            print "#!!!!! Error: Range entry in $filename line $line_no is not inside a config block.\n";
+        }
+        $errors_found++;
+    }
+}
+
+#-------------------------------------------------------------------------------
+# handle_default
+#-------------------------------------------------------------------------------
+sub handle_default {
+    my ( $default, $name, $inside_config, $inside_choice, $filename, $line_no ) = @_;
+    my $expression;
+    ( $default, $expression ) = handle_if_line( $default, $inside_config, $filename, $line_no );
+
+    if ($inside_config) {
+        handle_expressions( $default, $inside_config, $filename, $line_no );
+        my $sym_num = $symbols{$inside_config}{count};
+
+        unless ( exists $symbols{$inside_config}{$sym_num}{default_max} ) {
+            $symbols{$inside_config}{$sym_num}{default_max} = 0;
+        }
+        my $default_max = $symbols{$inside_config}{$sym_num}{default_max};
+        $symbols{$inside_config}{$sym_num}{default}{$default_max}{default}         = $default;
+        $symbols{$inside_config}{$sym_num}{default}{$default_max}{default_line_no} = $line_no;
+        if ($expression) {
+            $symbols{$inside_config}{$sym_num}{default}{$default_max}{default_depends_on} = $expression;
+        }
+    }
+    elsif ($inside_choice) {
+        handle_expressions( $default, $inside_config, $filename, $line_no );
+    }
+    else {
+        unless ($suppress_error_output) {
+            print "#!!!!! Error: $name entry in $filename line $line_no is not inside a config or choice block.\n";
+        }
+        $errors_found++;
+    }
+}
+
+#-------------------------------------------------------------------------------
+# handle_if_line
+#-------------------------------------------------------------------------------
+sub handle_if_line {
+    my ( $exprline, $inside_config, $filename, $line_no ) = @_;
+
+    if ( $exprline !~ /if/ ) {
+        return ( $exprline, "" );
+    }
+
+    #remove any quotes that might have an 'if' in them
+    my $savequote;
+    if ( $exprline =~ /^\s*("[^"]+")/ ) {
+        $savequote = $1;
+        $exprline =~ s/^\s*("[^"]+")//;
+    }
+
+    my $expr = "";
+    if ( $exprline =~ /\s*if\s+(.*)$/ ) {
+        $expr = $1;
+        $exprline =~ s/\s*if\s+.*$//;
+
+        if ($expr) {
+            handle_expressions( $expr, $inside_config, $filename, $line_no );
+        }
+    }
+
+    if ($savequote) {
+        $exprline = $savequote;
+    }
+
+    return ( $exprline, $expr );
+}
+
+#-------------------------------------------------------------------------------
+# handle_expressions - log which symbols are being used
+#-------------------------------------------------------------------------------
+sub handle_expressions {
+    my ( $exprline, $inside_config, $filename, $line_no ) = @_;
+
+    return unless ($exprline);
+
+    #filter constant symbols first
+    if ( $exprline =~ /^\s*"?([yn])"?\s*$/ ) {                           # constant y/n
+        return;
+    }
+    elsif ( $exprline =~ /^\s*"?((?:-)\d+)"?\s*$/ ) {                    # int values
+        return;
+    }
+    elsif ( $exprline =~ /^\s*"?((?:-)?(?:0x)?\p{XDigit})+"?\s*$/ ) {    # hex values
+        return;
+    }
+    elsif ( $exprline =~ /^\s*("[^"]*")\s*$/ ) {                         # String values
+        return;
+    }
+    elsif ( $exprline =~ /^\s*([A-Za-z0-9_]+)\s*$/ ) {                   # <symbol>                             (1)
+        add_referenced_symbol( $1, $filename, $line_no );
+    }
+    elsif ( $exprline =~ /^\s*!(.+)$/ ) {                                # '!' <expr>                           (5)
+
+        handle_expressions( $1, $inside_config, $filename, $line_no );
+    }
+    elsif ( $exprline =~ /^\s*\(([^)]+)\)\s*$/ ) {                       # '(' <expr> ')'                       (4)
+        handle_expressions( $1, $inside_config, $filename, $line_no );
+    }
+    elsif ( $exprline =~ /^\s*(.+)\s*!=\s*(.+)\s*$/ ) {                  # <symbol> '!=' <symbol>               (3)
+        handle_expressions( $1, $inside_config, $filename, $line_no );
+        handle_expressions( $2, $inside_config, $filename, $line_no );
+    }
+    elsif ( $exprline =~ /^\s*(.+)\s*=\s*(.+)\s*$/ ) {                   # <symbol> '=' <symbol>                (2)
+        handle_expressions( $1, $inside_config, $filename, $line_no );
+        handle_expressions( $2, $inside_config, $filename, $line_no );
+    }
+    elsif ( $exprline =~ /^\s*([^(]+|\(.+\))\s*&&\s*(.+)\s*$/ ) {        # <expr> '&&' <expr>                   (6)
+        handle_expressions( $1, $inside_config, $filename, $line_no );
+        handle_expressions( $2, $inside_config, $filename, $line_no );
+    }
+    elsif ( $exprline =~ /^\s*([^(]+|\(.+\))\s*\|\|\s*(.+)\s*$/ ) {      # <expr> '||' <expr>                   (7)
+        handle_expressions( $1, $inside_config, $filename, $line_no );
+        handle_expressions( $2, $inside_config, $filename, $line_no );
+    }
+
+    # work around kconfig spec violation for now - paths not in quotes
+    elsif ( $exprline =~ /^\s*([A-Za-z0-9_\-\/]+)\s*$/ ) {               # <symbol>                             (1)
+        return;
+    }
+    else {
+        unless ($suppress_error_output) {
+            print "#### Unrecognized expression '$exprline' in $filename line $line_no.\n";
+        }
+        $errors_found++;
+    }
+
+    return;
+}
+
+#-------------------------------------------------------------------------------
+# add_referenced_symbol
+#-------------------------------------------------------------------------------
+sub add_referenced_symbol {
+    my ( $symbol, $filename, $line_no ) = @_;
+    if ( exists $referenced_symbols{$symbol} ) {
+        $referenced_symbols{$symbol}{count}++;
+        $referenced_symbols{$symbol}{ $referenced_symbols{$symbol}{count} }{filename} = $filename;
+        $referenced_symbols{$symbol}{ $referenced_symbols{$symbol}{count} }{line_no}  = $line_no;
+    }
+    else {
+        $referenced_symbols{$symbol}{count}       = 0;
+        $referenced_symbols{$symbol}{0}{filename} = $filename;
+        $referenced_symbols{$symbol}{0}{line_no}  = $line_no;
+    }
+}
+
+#-------------------------------------------------------------------------------
+# handle_help
+#-------------------------------------------------------------------------------
+{
+    #create a non-global static variable by enclosing it and the subroutine
+    my $help_whitespace = "";    #string to show length of the help whitespace
+
+    sub handle_help {
+        my ( $line, $inside_help, $inside_config, $inside_choice, $filename, $line_no ) = @_;
+
+        if ($inside_help) {
+
+            #get the indentation level if it's not already set.
+            if ( ( !$help_whitespace ) && ( $line !~ /^[\r\n]+/ ) ) {
+                $line =~ /^(\s+)/;    #find the indentation level.
+                $help_whitespace = $1;
+                if ( !$help_whitespace ) {
+                    unless ($suppress_error_output) {
+                        print "# Warning: $filename line $line_no help text starts with no whitespace.\n";
+                    }
+                    return $inside_help;
+                    $errors_found++;
+                }
+            }
+
+            #help ends at the first line which has a smaller indentation than the first line of the help text.
+            if ( ( $line !~ /$help_whitespace/ ) && ( $line !~ /^[\r\n]+/ ) ) {
+                $inside_help     = 0;
+                $help_whitespace = "";
+            }
+            else {    #if it's not ended, add the line to the helptext array for the symbol's instance
+                if ($inside_config) {
+                    my $sym_num = $symbols{$inside_config}{count};
+                    if ($help_whitespace) { $line =~ s/^$help_whitespace//; }
+                    push( @{ $symbols{$inside_config}{$sym_num}{helptext} }, $line );
+                }
+            }
+        }
+        elsif ( ( $line =~ /^(\s*)help/ ) || ( $line =~ /^(\s*)---help---/ ) ) {
+            $inside_help = $line_no;
+            if ( ( !$inside_config ) && ( !$inside_choice ) ) {
+                unless ($suppress_error_output) {
+                    print "# Note: $filename line $line_no help is not inside a config or choice block.\n";
+                }
+                $errors_found++;
+            }
+            elsif ($inside_config) {
+                $help_whitespace = "";
+                my $sym_num = $symbols{$inside_config}{count};
+                $symbols{$inside_config}{$sym_num}{help_line_no} = $line_no;
+                $symbols{$inside_config}{$sym_num}{helptext}     = ();
+            }
+        }
+        return $inside_help;
+    }
+}
+
+#-------------------------------------------------------------------------------
+# handle_type
+#-------------------------------------------------------------------------------
+sub handle_type {
+    my ( $type, $inside_config, $filename, $line_no ) = @_;
+
+    my $expression;
+    ( $type, $expression ) = handle_if_line( $type, $inside_config, $filename, $line_no );
+
+    if ($inside_config) {
+        if ( exists( $symbols{$inside_config}{type} ) ) {
+            if ( $symbols{$inside_config}{type} !~ /$type/ ) {
+                print "#!!!!! Error: Config '$inside_config' type entry $type at $filename line $line_no does not match";
+                print " the previously defined type $symbols{$inside_config}{type}";
+                print " defined in $symbols{$inside_config}{type_file} on line";
+                print " $symbols{$inside_config}{type_line_no}.\n";
+                $errors_found++;
+            }
+        }
+        else {
+            $symbols{$inside_config}{type}         = $type;
+            $symbols{$inside_config}{type_file}    = $filename;
+            $symbols{$inside_config}{type_line_no} = $line_no;
+        }
+    }
+    else {
+        unless ($suppress_error_output) {
+            print "#!!!!! Error: Type entry in $filename line $line_no is not inside a config block.\n";
+        }
+        $errors_found++;
+    }
+}
+
+#-------------------------------------------------------------------------------
+# handle_prompt
+#-------------------------------------------------------------------------------
+sub handle_prompt {
+    my ( $prompt, $name, $menu_array_ref, $inside_config, $inside_choice, $filename, $line_no ) = @_;
+
+    my $expression;
+    ( $prompt, $expression ) = handle_if_line( $prompt, $inside_config, $filename, $line_no );
+
+    if ($inside_config) {
+        if ( $prompt !~ /^\s*$/ ) {
+            if ( $prompt =~ /^\s*"([^"]*)"\s*$/ ) {
+                $prompt = $1;
+            }
+
+            if ( !defined @$menu_array_ref[0] ) {
+                unless ($suppress_error_output) {
+                    print "#!!!!! Warning: Symbol  '$inside_config' with prompt '$prompt' appears outside of a menu in $filename at line $line_no.  This is discouraged.\n";
+                }
+                $errors_found++;
+            }
+
+            my $sym_num = $symbols{$inside_config}{count};
+            unless ( exists $symbols{$inside_config}{$sym_num}{prompt_max} ) {
+                $symbols{$inside_config}{$sym_num}{prompt_max} = 0;
+            }
+            my $prompt_max = $symbols{$inside_config}{$sym_num}{prompt_max};
+            $symbols{$inside_config}{$sym_num}{prompt}{$prompt_max}{prompt}         = $prompt;
+            $symbols{$inside_config}{$sym_num}{prompt}{$prompt_max}{prompt_line_no} = $line_no;
+            if ($expression) {
+                $symbols{$inside_config}{$sym_num}{prompt}{$prompt_max}{prompt_depends_on} = $expression;
+            }
+        }
+    }
+    elsif ($inside_choice) {
+
+        #do nothing
+    }
+    else {
+        unless ($suppress_error_output) {
+            print "#!!!!! Error: $name entry in $filename line $line_no is not inside a config or choice block.\n";
+        }
+        $errors_found++;
+    }
+}
+
+#-------------------------------------------------------------------------------
+# simple_line_checks - Does some basic checks on the current line, then cleans the line
+#  up for further processing.
+#-------------------------------------------------------------------------------
+sub simple_line_checks {
+    my ( $line, $filename, $line_no ) = @_;
+
+    #check for spaces instead of tabs
+    if ( $line =~ /^ +/ ) {
+        unless ($suppress_error_output) {
+            print "# Note: $filename line $line_no starts with a space.\n";
+        }
+        $errors_found++;
+    }
+
+    #verify a linefeed at the end of the line
+    if ( $line !~ /.*\n/ ) {
+        unless ($suppress_error_output) {
+            print "#!!!!! Warning: $filename line $line_no does not end with linefeed.  This can cause the line to not be recognized by the Kconfig parser.\n";
+            print "#($line)\n";
+        }
+        $errors_found++;
+        $line =~ s/\s*$//;
+    }
+    else {
+        chop($line);
+    }
+
+    return $line;
+}
+
+#-------------------------------------------------------------------------------
+# load_kconfig_file - Loads a single Kconfig file or expands * wildcard
+#-------------------------------------------------------------------------------
+sub load_kconfig_file {
+    my ( $input_file, $loadfile, $loadline, $expanded, $topfile, $topline ) = @_;
+    my @file_data;
+    my @dir_file_data;
+
+    #recursively handle coreboot's new source glob operator
+    if ( $input_file =~ /^(.*?)\/\*\/(.*)$/ ) {
+        my $dir_prefix = $1;
+        my $dir_suffix = $2;
+        if ( -d "$dir_prefix" ) {
+
+            opendir( D, "$dir_prefix" ) || die "Can't open directory '$dir_prefix'\n";
+            my @dirlist = sort { $a cmp $b } readdir(D);
+            closedir(D);
+
+            while ( my $directory = shift @dirlist ) {
+
+                #ignore non-directory files
+                if ( ( -d "$dir_prefix/$directory" ) && !( $directory =~ /^\..*/ ) ) {
+                    push @dir_file_data, load_kconfig_file( "$dir_prefix/$directory/$dir_suffix", $input_file, $loadline, 1, $loadfile, $loadline );
+                }
+            }
+        }
+
+        #the directory should exist when using a glob
+        else {
+            unless ($suppress_error_output) {
+                print "#!!!!! Warning: Could not find dir '$dir_prefix'\n";
+            }
+            $errors_found++;
+        }
+    }
+
+    #if the file exists, try to load it.
+    elsif ( -e "$input_file" ) {
+
+        #throw a warning if the file has already been loaded.
+        if ( exists $loaded_files{$input_file} ) {
+            unless ($suppress_error_output) {
+                print "#!!!!! Warning: '$input_file' sourced in '$loadfile' at line $loadline was already loaded by $loaded_files{$input_file}\n";
+            }
+            $errors_found++;
+        }
+
+        #load the file's contents and mark the file as loaded for checking later
+        open( my $HANDLE, "<", "$input_file" ) or die "Error: could not open file '$input_file'\n";
+        @file_data = <$HANDLE>;
+        close $HANDLE;
+        $loaded_files{$input_file} = "'$loadfile' line $loadline";
+    }
+
+    # if the file isn't being loaded from a glob, it should exist.
+    elsif ( $expanded == 0 ) {
+        unless ($suppress_error_output) {
+            print "#!!!!! Warning: Could not find file '$input_file' sourced in $loadfile at line $loadline\n";
+        }
+        $errors_found++;
+    }
+
+    my $line_in_file = 0;
+    while ( my $line = shift @file_data ) {
+
+        #handle line continuation.
+        my $continue_line = 0;
+        while ($line =~ /(.*)\s+\\$/) {
+            my $text = $1;
+
+            # get rid of leading whitespace on all but the first and last lines
+            $text =~ s/^\s*/ / if ($continue_line);
+
+            $dir_file_data[$line_in_file]{text} .= $text;
+            $line = shift @file_data;
+            $continue_line++;
+
+            #put the data into the continued lines (other than the first)
+            $line =~ /^\s*(.*)\s*$/;
+
+            $dir_file_data[$line_in_file + $continue_line]{text} = "\t# continued line ( " . $1 . " )\n";
+            $dir_file_data[$line_in_file + $continue_line]{filename}     = $input_file;
+            $dir_file_data[$line_in_file + $continue_line]{file_line_no} = $line_in_file + $continue_line + 1;
+
+            #get rid of multiple leading spaces for last line
+            $line = " $1\n";
+        }
+
+        $dir_file_data[$line_in_file]{text}         .= $line;
+        $dir_file_data[$line_in_file]{filename}     = $input_file;
+        $dir_file_data[$line_in_file]{file_line_no} = $line_in_file + 1;
+
+        $line_in_file++;
+        if ($continue_line) {
+            $line_in_file += $continue_line;
+        }
+    }
+
+    if ($topfile) {
+        my %file_data;
+        $file_data{text}         = "\t### File '$input_file' loaded from '$topfile' line $topline\n" ;
+        $file_data{filename}     = $topfile;
+        $file_data{file_line_no} = "($topline)";
+        unshift (@dir_file_data, \%file_data);
+    }
+
+    return @dir_file_data;
+}
+
+
+#-------------------------------------------------------------------------------
+# print_wholeconfig - prints out the parsed Kconfig file
+#-------------------------------------------------------------------------------
+sub print_wholeconfig {
+
+    return unless $print_full_output;
+
+    for ( my $i = 0 ; $i < $#wholeconfig ; $i++ ) {
+        my $line = $wholeconfig[$i];
+        chop( $line->{text} );
+
+        #replace tabs with spaces for consistency
+        $line->{text} =~ s/\t/        /g;
+        printf "%-120s # $line->{filename} line $line->{file_line_no}\n", $line->{text};
+    }
+}
+
+#-------------------------------------------------------------------------------
+# check_if_file_referenced - checks for kconfig files that are not being parsed
+#-------------------------------------------------------------------------------
+sub check_if_file_referenced {
+    my $filename = $File::Find::name;
+    if ( ( $filename =~ /Kconfig/ ) && ( !exists $loaded_files{$filename} ) ) {
+        unless ($suppress_error_output) {
+            print "#!!!!! Warning: '$filename' is never referenced\n";
+        }
+        $errors_found++;
+    }
+}
+
+#-------------------------------------------------------------------------------
+# check_arguments parse the command line arguments
+#-------------------------------------------------------------------------------
+sub check_arguments {
+    my $show_usage = 0;
+    GetOptions(
+        'help|?'         => sub { usage() },
+        'o|output=s'     => \$output_file,
+        'p|print'        => \$print_full_output,
+        'w|warnings_off' => \$suppress_error_output,
+        'path=s'         => \$top_dir,
+        'c|config=s'     => \$config_file,
+        'G|no_git_grep'  => \$dont_use_git_grep,
+    );
+}
+
+#-------------------------------------------------------------------------------
+# usage - Print the arguments for the user
+#-------------------------------------------------------------------------------
+sub usage {
+    print "kconfig_lint <options>\n";
+    print " -o|--output=file    Set output filename\n";
+    print " -p|--print          Print full output\n";
+    print " -w|--warnings_off   Don't print warnings\n";
+    print " --path=dir          Path to top level kconfig\n";
+    print " -c|--config=file    Filename of config file to load\n";
+    print " -G|--no_git_grep    Use standard grep tools instead of git grep\n";
+
+    exit(0);
+}
+
+1;