produce_graph.pl

#!/usr/bin/env perl
use strict;
use Log::Log4perl qw(:easy);
Log::Log4perl->easy_init($ERROR);


# perl -ne 'if($_ !~ /\s*\*/){print;}'|perl -ne 'if(/([a-zA-Z0-9]+)\s*[=;]/){print "$1\n";}'|perl -ne 'if($_ !~ /[0-9]+/){print;}' > variables.txt
my %var_dict = ();
if($#ARGV + 1 != 1){
    print STDERR "Usage: ./produce_graph.pl source_file\n";
    exit(1);
}


my @lines = ();

open(INPUT, $ARGV[0]) or die "Cannot open file $ARGV[0].\n";
my $symbol = '[a-zA-Z_]\w*';
while(<INPUT>){
    if($_ =~ /^\s*\*/){
	next;
    }
    # add the current line to the array @lines
    push(@lines, $_);

    # remove constructor funcitions
    $_ =~ s/\([^\)]\)//g;

    # parse variables from the current line
    while($_ =~ /($symbol)\s*[\[,=;]/g){
      DEBUG "vars:$1\n";
      $var_dict{$1} = 1;	    
    }
    
    # parse C++ function parameters
    if($_ =~ /::/){
      while($_ =~ /($symbol)\s*[\),]/g){
	    $var_dict{$1} = 1;
      }
    }
    
    # parse pointers
    while($_ =~ /($symbol)\s*->/g){
      $var_dict{$1} = 1;
    }

    # parse struct 
    # if($_ =~ /struct\s+\S+\s+($symbol)/){
    #   $var_dict{$1} = 1;
    # }
}
close(INPUT);

sub search_for_var{

    my $expression = shift;
    DEBUG "left expression:$expression ";
    # first, we need to trim member variables
    while($expression =~ s/\.$symbol//g){};

    use vars qw(%var_dict);

    #my $matched_variable_length = -1;
    #my $matched_variable;
    foreach my $variable (keys %var_dict){
      if($expression =~ /\b$variable\W/){ # do a word search of teh variable
	    #if(length($variable) > $matched_variable_length){
	    #$matched_variable_length = length($variable);
	    #$matched_variable = $variable;
	    #}
        DEBUG "matched:$variable";
	    return $variable;
      }
    }
    
    return "";
    #return $matched_variable;
}

sub search_for_vars{
    my $expression = shift;
    chomp $expression;
    use vars qw(%var_dict);

    #print "right:$expression ";
    my @var_list = ();
    foreach my $variable (keys %var_dict){
      #print ",var:$variable ";
      if($expression =~ /\b$variable\b/){ # do a word search of the variable
        #print ",captured var:$variable ";
	    push(@var_list, $variable);
        next;
      }
      
      # special, support pure numerical values on the right side
      if($expression =~ /(\d+)\s*;/){
        push(@var_list, $1);
      }
    }

    return @var_list;
}

my @remaining_line = ();

my %result_hash = ();
# parse function calls first
foreach (@lines) {
  if ($_ =~ /($symbol)(?:\.|->)($symbol)\s*\((.*)$/) {
    #print "Function call:$_";
	my $left_var = "$1";
	my $right_expression = $3;
	my @right_vars = search_for_vars($right_expression);
	foreach my $right_var (@right_vars) {
      $result_hash{"\t$right_var -> $left_var;\n"} = 1;
	}

	# this line is also an assignment line
	if ($_ =~ /([^=]*)=/) {
      push(@remaining_line, "$1 = $left_var;");
      #print "Complex statement $_ -------> $1 = $left_var;\n";
	}
	#push(@remaining_line, )
  } else {
	push(@remaining_line, $_);
  }

}


# then parse assignments
foreach(@remaining_line){

    if($_ =~ /=/){
	# assignment operation
	#print "Remaining line:$_\n";
	my ($left_expression, $right_expression) = split(/=/, $_);
	#print "left_expression:$left_expression right_expression:$right_expression\n";
	my $left_var = search_for_var($left_expression);
	DEBUG "left_var:$left_var ";
	if($left_var ne ""){
        DEBUG "right_expression:$right_expression,";
	    my @right_vars = search_for_vars($right_expression);
	    DEBUG "right_vars: @right_vars $#right_vars\n";
	    if($#right_vars + 1 > 0){
		foreach my $right_var (@right_vars){
		    $result_hash{"\t$right_var -> $left_var;\n"} = 1;
		}
	    }
	}
    }
}


my $output_dot = "";
my $output_pdf = "";
if($ARGV[0] =~ /([^\.]+)\./){
    $output_dot = "$1.dot";
    $output_pdf = "$1.pdf";
}else{
    $output_dot = $ARGV[0].".dot";
    $output_pdf = $ARGV[0].".pdf";
}

open(DOT_OUTPUT, ">$output_dot") or die "Cannot open $output_dot for output";
print DOT_OUTPUT  "digraph G{\n";
foreach my $line (keys %result_hash){
    print DOT_OUTPUT $line;
}
print DOT_OUTPUT "}\n";
close(DOT_OUTPUT);


system("dot -Tpdf -o $output_pdf $output_dot");