$ ./makev.pl 10000 > test.10k.v
$ time perl_5.8.8 -w testv.pl test.10k.v
LAST MODULE (Perl 5.008008): je0dhj
perl_5.8.8 -w testv.pl test.10k.v  0.01s user 0.01s system 0% cpu 11.352 total
$ time perl_5.30 -w testv.pl test.10k.v
LAST MODULE (Perl 5.030000): je0dhj
perl_5.30 -w testv.pl test.10k.v  0.01s user 0.02s system 0% cpu 26.291 total

##</code><code>##

!/usr/bin/perl -w
use Text::Wrap;
use strict;

my $num = shift or die "num?\n";

my @chars = ( "a" .. "z", 0 .. 9 );

for my $i (0 .. $num) {

    my $name = join("", @chars[ map { rand @chars } ( 1 .. 2+int(rand(8)) )]);
    my @io   = map { "p${name}${_}" } (0..int(rand(100)));
    my @hier = map { "m${name}${_}" } (0..int(rand(20)));
    my @leaf = map { "s${name}${_}" } (0..int(rand(200)));

    print "module ${name} ( ", wrap('', '  ', join(", ", @io)), "\n);\n";
    print "  inout  $_;\n" foreach @io;
    print "  wire   $_;\n" foreach @io;

    for my $leaf (@leaf) {
        my @conn = map { ".P${name}${_} (n${name}${_})" } (0..int(rand(5)));
        print "$leaf u_$leaf ( ", wrap('', '  ', join(", ", @conn)), "\n);\n";
    }

    for my $hier (@hier) {
        my @conn = map { ".p${name}${_} (n${name}${_})" } (0..int(rand(100)));
        print "$hier u_$hier ( ", wrap('', '  ', join(", ", @conn)), "\n);\n";
    }
    print "endmodule\n\n";
}

##</code><code>##

use strict;
use File::Slurp;

my $file = shift or die "file?\n";
my $text = read_file($file);

parse_v($text);

sub parse_v {
    my $text = shift;
    my $name;
    {
        last if $text =~ /\G \s* \Z/gcmsx;

        if     ($text =~ /\G \s* ^ \s* module \s+ (\S+?) \s* \( \s* (.*?) \s* \) \s* ;/gcmsx) { $name = $1 }
        elsif  ($text =~ /\G \s* ^ \s* endmodule        /gcmsx) { }
        elsif  ($text =~ /\G \s* ^ \s* \S+ \s+ .*? \s* ;/gcmsx) { }
        else { die "ERROR: unknown syntax\n" }

        redo;
    }
    print "LAST MODULE (Perl $]): $name\n";
}