diff --git a/Makefile.in b/Makefile.in
index 642802c3e..0c033bab6 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -477,6 +477,8 @@ YAPF_FLAGS = -i
 YAPF_FILES = \
 	examples/xml_py/vl_file_copy \
 	examples/xml_py/vl_hier_graph \
+	nodist/code_coverage \
+	nodist/code_coverage.dat \
 	nodist/dot_importer \
 	nodist/fuzzer/actual_fail \
 	nodist/fuzzer/generate_dictionary \
diff --git a/nodist/code_coverage b/nodist/code_coverage
index c7bd6d11b..68e347d32 100755
--- a/nodist/code_coverage
+++ b/nodist/code_coverage
@@ -1,511 +1,398 @@
-#!/usr/bin/env perl
-# See copyright, etc in below POD section.
+#!/usr/bin/env python3
 ######################################################################
 
-use warnings;
-use Cwd;
-use File::Copy qw(cp);
-use File::Path qw(mkpath);
-use File::Spec;
-use FindBin qw($RealBin);
-use Getopt::Long;
-use Parallel::Forker;
-use Unix::Processors;
-use IO::File;
-use Pod::Usage;
-use strict;
-use vars qw($Debug);
+import argparse
+import glob
+import multiprocessing
+import os
+import re
+import subprocess
 
-our $Opt_Stop = 1;
-our $Opt_Fastcov = 1;
-our $Exclude_Branch_Regexp;
-our $Exclude_Line_Regexp;
-our $Remove_Gcda_Regexp;
+RealPath = os.path.dirname(os.path.realpath(__file__))
+Exclude_Branch_Regexps = []
+Exclude_Line_Regexps = []
+Remove_Gcda_Regexps = []
+Remove_Sources = []
+Source_Globs = []
 
-our @Remove_Sources;
-our @Source_Globs;
+if 'VERILATOR_ROOT' not in os.environ:
+    os.environ['VERILATOR_ROOT'] = os.getcwd()
 
-our $Fork = new Parallel::Forker(use_sig_child => 1, poll_interval => 10*1000);
-$Fork->max_proc(Unix::Processors->new->max_online * 1.5);
-$SIG{CHLD} = sub { Parallel::Forker::sig_child($Fork); };
-$SIG{TERM} = sub { $Fork->kill_tree_all('TERM') if $Fork && $Fork->in_parent; die "Quitting...\n"; };
+######################################################################
 
-$ENV{VERILATOR_ROOT} ||= Cwd::getcwd();
 
-#======================================================================
-# main
+def test():
+    if not os.path.exists("nodist/code_coverage.dat"):
+        sys.exit("%Error: Run code_coverage from the top of the verilator kit")
+    exec(open("./nodist/code_coverage.dat").read())
 
-our $Opt_Hashset;
-our $opt_stages = '';
-our $Opt_Scenarios;
-our %Opt_Stages;
-our @Opt_Tests;
-
-autoflush STDOUT 1;
-autoflush STDERR 1;
-Getopt::Long::config("no_auto_abbrev");
-if (! GetOptions(
-          "debug"       => sub { $Debug = 1; },
-          "hashset=s"   => \$Opt_Hashset,  # driver.pl hashset
-          "<>"          => sub { die "%Error: Unknown parameter: $_[0]\n"; },
-          "fastcov!"    => \$Opt_Fastcov,  # use fastcov, not documented, for debug
-          "scenarios=s" => \$Opt_Scenarios,  # driver.pl scenarios
-          "stage=s"     => \$opt_stages,  # starting stage number
-          "stages=s"    => \$opt_stages,  # starting stage number
-          "stop!"       => \$Opt_Stop,  # stop/do not stop on error in tests
-          "test=s@"     => \@Opt_Tests,  # test name
-    )) {
-    die "%Error: Bad usage, try 'code_coverage --help'\n";
-}
-
-{
-    my $start = 0;
-    my $end = 99;
-    if ($opt_stages && $opt_stages =~ /^(\d+)$/) {
-        $start = $end = $1;
-    } elsif ($opt_stages && $opt_stages =~ /^(\d+)-(\d+$)$/) {
-        $start = $1; $end = $2;
-    } elsif ($opt_stages && $opt_stages =~ /^-(\d+$)$/) {
-        $end = $1;
-    } elsif ($opt_stages && $opt_stages =~ /^(\d+)-$/) {
-        $start = $1;
-    } elsif ($opt_stages) {
-        die "%Error: --stages not understood: $opt_stages,";
-    }
-    for (my $n = $start; $n <= $end; ++$n) { $Opt_Stages{$n} = 1; }
-}
-
-test();
-exit(0);
-
-#######################################################################
-
-sub test {
-    -r "nodist/code_coverage.dat" or die "%Error: Run from the top of the verilator kit,";
-    require "./nodist/code_coverage.dat";
-
-    if ($Opt_Stages{1}) {
-        ci_fold_start("configure");
-        print "Stage 1: configure (coverage on)\n";
-        run("make distclean || true");
-        run("autoconf");
+    if Args.stage_enabled[1]:
+        ci_fold_start("configure")
+        print("Stage 1: configure (coverage on)")
+        run("make distclean || true")
+        run("autoconf")
         # Exceptions can pollute the branch coverage data
-        run("./configure --enable-longtests CXX='g++ --coverage -fno-exceptions -DVL_GCOV'");
-        ci_fold_end();
-    }
+        run("./configure --enable-longtests CXX='g++ --coverage -fno-exceptions -DVL_GCOV'"
+            )
+        ci_fold_end()
 
-    if ($Opt_Stages{2}) {
-        ci_fold_start("build");
-        print "Stage 2: build\n";
-        my $nproc = Unix::Processors->new->max_online;
-        run("make -k -j $nproc VERILATOR_NO_OPT_BUILD=1");
+    if Args.stage_enabled[2]:
+        ci_fold_start("build")
+        print("Stage 2: build")
+        nproc = multiprocessing.cpu_count()
+        run("make -k -j " + str(nproc) + " VERILATOR_NO_OPT_BUILD=1")
         # The optimized versions will not collect good coverage, overwrite them
-        run("cp bin/verilator_bin_dbg bin/verilator_bin");
-        run("cp bin/verilator_coverage_bin_dbg bin/verilator_coverage_bin");
-        ci_fold_end();
-    }
+        run("cp bin/verilator_bin_dbg bin/verilator_bin")
+        run("cp bin/verilator_coverage_bin_dbg bin/verilator_coverage_bin")
+        ci_fold_end()
 
-    if ($Opt_Stages{3}) {
-        ci_fold_start("test");
-        print "Stage 3: make tests (with coverage on)\n";
-        if ($#Opt_Tests < 0) {
-            run("make examples VERILATOR_NO_OPT_BUILD=1")
-                if !$Opt_Scenarios || $Opt_Scenarios =~ /dist/i;
-            run("make test_regress VERILATOR_NO_OPT_BUILD=1"
-                . ($Opt_Scenarios ? " SCENARIOS='".$Opt_Scenarios."'" : "")
-                . ($Opt_Hashset ? " DRIVER_HASHSET='--hashset=".$Opt_Hashset."'" : "")
-                . ($Opt_Stop ? '' : ' || true'));
-        } else {
-            foreach my $test (@Opt_Tests) {
-                if (! -f $test && -f "test_regress/t/${test}") {
-                    $test = "test_regress/t/${test}";
-                }
-                run($test);
-            }
-        }
-        ci_fold_end();
-    }
+    if Args.stage_enabled[3]:
+        ci_fold_start("test")
+        print("Stage 3: make tests (with coverage on)")
+        if not Args.tests:
+            if not Args.scenarios or re.match('dist', Args.scenarios):
+                run("make examples VERILATOR_NO_OPT_BUILD=1")
+            run("make test_regress VERILATOR_NO_OPT_BUILD=1" +
+                (" SCENARIOS='" + Args.scenarios +
+                 "'" if Args.scenarios else "") +
+                (" DRIVER_HASHSET='--hashset=" + Args.hashset +
+                 "'" if Args.hashset else "") +
+                ('' if Args.stop else ' || true'))
+        else:
+            for test in Args.tests:
+                if not os.path.exists(test) and os.path.exists(
+                        "test_regress/t/" + test):
+                    test = "test_regress/t/" + test
+                run(test)
+        ci_fold_end()
 
-    my $cc_dir = "nodist/obj_dir/coverage";
-    if ($Opt_Stages{4}) {
-        ci_fold_start("gcno");
-        print "Stage 4: Create gcno files under $cc_dir\n";
-        mkpath($cc_dir);
-        mkpath("$cc_dir/info");
-        my $dats = `find . -print | grep .gcda`;
-        my %dats;
-        foreach my $dat (split '\n', $dats) {
-            $dats{$dat} = 1;
-        }
-        foreach my $dat (sort keys %dats) {
-            (my $gcno = $dat) =~ s!\.gcda$!.gcno!;
-            if ($dat =~ /$Remove_Gcda_Regexp/) {
-                # Remove .gcda/.gcno for files we don't care about before we slowly
-                # read them
-                unlink $dat;
-                unlink $gcno;
-                delete $dats{$dat};
-                next;
-            }
-        }
-        $dats = `find . -print | grep .gcno`;
-        my %gcnos;
-        foreach my $gcno (split '\n', $dats) {
-            (my $gbase = $gcno) =~ s!.*/!!;
-            $gcnos{$gbase} = File::Spec->rel2abs($gcno);
-        }
+    cc_dir = "nodist/obj_dir/coverage"
+    if Args.stage_enabled[4]:
+        ci_fold_start("gcno")
+        print("Stage 4: Create gcno files under " + cc_dir)
+        os.makedirs(cc_dir, exist_ok=True)
+        os.makedirs(cc_dir + "/info", exist_ok=True)
+
+        sp = subprocess.Popen("find . -print | grep .gcda",
+                              shell=True,
+                              stdout=subprocess.PIPE)
+        datout = sp.stdout.read()
+        dats = {}
+        for dat in datout.splitlines():
+            dat = dat.decode('utf-8')
+            dats[dat] = 1
+        for dat in sorted(dats.keys()):
+            gcno = re.sub(r'\.gcda$', '.gcno', dat)
+            for regexp in Remove_Gcda_Regexps:
+                if re.search(regexp, dat):
+                    # Remove .gcda/.gcno for files we don't care about before we slowly
+                    # read them
+                    os.unlink(dat)
+                    os.unlink(gcno)
+                    del dats[dat]
+                    break
+
+        sp = subprocess.Popen("find . -print | grep .gcno",
+                              shell=True,
+                              stdout=subprocess.PIPE)
+        datout = sp.stdout.read()
+        gcnos = {}
+        for gcno in datout.splitlines():
+            gcno = gcno.decode('utf-8')
+            gbase = re.sub(r'.*/', '', gcno, count=1)
+            gcnos[gbase] = os.path.abspath(gcno)
         # We need a matching .gcno for every .gcda, try to find a matching file elsewhere
-        foreach my $dat (sort keys %dats) {
-            (my $gcno = $dat) =~ s!\.gcda$!.gcno!;
-            (my $gbase = $gcno) =~ s!.*/!!;
-            if (!-r $gcno) {
-                if ($gcnos{$gbase}) {
-                    symlink($gcnos{$gbase}, $gcno)
-                        or die "%Error: can't ln -s $gcnos{$gbase} $gcno,";
-                } else {
-                    warn "MISSING .gcno for a .gcda: $gcno\n";
-                }
-            }
-        }
-        ci_fold_end();
-    }
+        for dat in sorted(dats):
+            gcno = re.sub(r'\.gcda$', '.gcno', dat)
+            gbase = re.sub(r'.*/', '', gcno, count=1)
+            if not os.path.exists(gcno):
+                if gbase in gcnos:
+                    os.symlink(gcnos[gbase], gcno)
+                else:
+                    print("MISSING .gcno for a .gcda: " + gcno,
+                          file=sys.stderr)
+        ci_fold_end()
 
-    if ($Opt_Stages{5} && $Opt_Fastcov) {
-        ci_fold_start("fastcov");
+    if Args.stage_enabled[5]:
+        ci_fold_start("fastcov")
         # Must run in root directory to find all files
-        mkpath($cc_dir);
-        #run("${RealBin}/fastcov.py -b -c src/obj_dbg -X".
-        #    " --exclude /usr --exclude test_regress"
-        #    ." -o ${cc_dir}/app_total.json");
-        run("${RealBin}/fastcov.py -b -c src/obj_dbg -X --lcov".
-            " --exclude /usr --exclude test_regress"
-            ." -o ${cc_dir}/app_total.info");
-        ci_fold_end();
-    }
+        os.makedirs(cc_dir, exist_ok=True)
+        run(RealPath + "/fastcov.py -b -c src/obj_dbg -X --lcov" +
+            " --exclude /usr --exclude test_regress" + " -o " + cc_dir +
+            "/app_total.info")
+        ci_fold_end()
 
-    if ($Opt_Stages{5} && !$Opt_Fastcov) {
-        ci_fold_start("infos");
-        print "Stage 5: make infos\n";
-        my $dats = `find . -print | grep .gcda`;
-        my %dirs;
-        foreach my $dat (split '\n', $dats) {
-            (my $dir = $dat) =~ s!/[^/]+$!!;
-            $dirs{$dir} = 1;
-        }
-
-        foreach my $dir (sort keys %dirs) {
-            (my $outname = $dir) =~ s![^a-zA-Z0-9]+!_!g;
-            $Fork->schedule(run_on_start => sub {
-                # .info may be empty, so ignore errors (unfortunately)
-                run("cd $cc_dir/info ; lcov -c -d ../../../../$dir --exclude /usr -o app_test_${outname}.info || true");
-                            })->run;
-        }
-        $Fork->wait_all;
-        ci_fold_end();
-    }
-
-    if ($Opt_Stages{6}) {
-        ci_fold_start("clone");
+    if Args.stage_enabled[6]:
+        ci_fold_start("clone")
         # No control file to override single lines, so replicate the sources
         # Also lets us see the insertion markers in the HTML source res
-        print "Stage 6: Clone sources under $cc_dir\n";
-        clone_sources($cc_dir);
-        ci_fold_end();
-    }
+        print("Stage 6: Clone sources under " + cc_dir)
+        clone_sources(cc_dir)
+        ci_fold_end()
 
-    if ($Opt_Stages{8} && !$Opt_Fastcov) {
-        ci_fold_start("copy");
-        print "Stage 8: Copy .gcno files\n";
-        my $dats = `find . -print | grep .gcno`;
-        foreach my $dat (sort (split '\n', $dats)) {
-            next if $dat =~ /$cc_dir/;
-            my $outdat = $cc_dir."/".$dat;
-            #print "cp $dat, $outdat);\n";
-            cp($dat, $outdat);
-        }
-        ci_fold_end();
-    }
+    if Args.stage_enabled[11]:
+        ci_fold_start("dirs")
+        print("Stage 11: Cleanup paths")
+        cleanup_abs_paths_info(cc_dir, cc_dir + "/app_total.info",
+                               cc_dir + "/app_total.info")
+        ci_fold_end()
 
-    if ($Opt_Stages{10} && !$Opt_Fastcov) {
-        ci_fold_start("combine");
-        print "Stage 10: Combine data files\n";
-        {
-            run("cd $cc_dir ; lcov -c -i -d src/obj_dbg -o app_base.info");
-            run("cd $cc_dir ; lcov -a app_base.info -o app_total.info");
-            my $infos = `cd $cc_dir ; find info -print | grep .info`;
-            my $comb = "";
-            my @infos = (sort (split /\n/, $infos));
-            foreach my $info (@infos) {
-                $comb .= " -a $info";
-                # Need to batch them to avoid overrunning shell command length limit
-                if (length($comb) > 10000 || $info eq $infos[$#infos]) {
-                    # .info may be empty, so ignore errors (unfortunately)
-                    run("cd $cc_dir ; lcov -a app_total.info $comb -o app_total.info || true");
-                    $comb = "";
-                }
-            }
-        }
-        ci_fold_end();
-    }
-
-    if ($Opt_Stages{11}) {
-        ci_fold_start("dirs");
-        print "Stage 11: Cleanup paths\n";
-        if ($Opt_Fastcov) {
-            cleanup_abs_paths_info($cc_dir, "$cc_dir/app_total.info", "$cc_dir/app_total.info");
-            #cleanup_abs_paths_json($cc_dir, "$cc_dir/app_total.json", "$cc_dir/app_total.json");
-        } else {
-            cleanup_abs_paths_info($cc_dir, "$cc_dir/app_total.info", "$cc_dir/app_total.info");
-        }
-        ci_fold_end();
-    }
-
-    if ($Opt_Stages{12}) {
-        ci_fold_start("filter");
-        print "Stage 12: Filter processed source files\n";
-        my $inc = '';
-        foreach my $glob (@Source_Globs) {
-            foreach my $infile (glob $glob) {
-                $inc .= " '$infile'";
-            }
-        }
-        my $exc = '';
-        foreach my $glob (@Remove_Sources) {
+    if Args.stage_enabled[12]:
+        ci_fold_start("filter")
+        print("Stage 12: Filter processed source files")
+        inc = ''
+        for globf in Source_Globs:
+            for infile in glob.glob(globf):
+                inc += " '" + infile + "'"
+        exc = ''
+        for globf in Remove_Sources:
             # Fastcov does exact match not globbing at present
             # Lcov requires whole path match so needs the glob
-            $glob =~ s!^\*!! if $Opt_Fastcov;
-            $glob =~ s!\*$!! if $Opt_Fastcov;
-            $exc .= " '$glob'";
-        }
-        if ($Opt_Fastcov) {
-            $inc = "--include ".$inc if $inc ne '';
-            $exc = "--exclude ".$exc if $exc ne '';
-            run("cd $cc_dir ; ${RealBin}/fastcov.py -C app_total.info ${inc} ${exc} -x --lcov -o app_total_f.info");
-        } else {
-            run("cd $cc_dir ; lcov --remove app_total.info $exc -o app_total_f.info");
-        }
-        ci_fold_end();
-    }
+            globf = re.sub(r'^\*', '', globf)
+            globf = re.sub(r'\*$', '', globf)
+            exc += " '" + globf + "'"
+        if inc != '':
+            inc = "--include " + inc
+        if exc != '':
+            exc = "--exclude " + exc
+        run("cd " + cc_dir + " ; " + RealPath +
+            "/fastcov.py -C app_total.info " + inc + " " + exc +
+            " -x --lcov -o app_total_f.info")
+        ci_fold_end()
 
-    if ($Opt_Stages{17}) {
-        ci_fold_start("report");
-        print "Stage 17: Create HTML\n";
-        run("cd $cc_dir ; genhtml app_total_f.info --demangle-cpp"
-            ." --rc lcov_branch_coverage=1 --rc genhtml_hi_limit=100 --output-directory html");
-        ci_fold_end();
-    }
+    if Args.stage_enabled[17]:
+        ci_fold_start("report")
+        print("Stage 17: Create HTML")
+        run("cd " + cc_dir + " ; genhtml app_total_f.info --demangle-cpp" +
+            " --rc lcov_branch_coverage=1 --rc genhtml_hi_limit=100 --output-directory html"
+            )
+        ci_fold_end()
 
-    if ($Opt_Stages{18}) {
-        ci_fold_start("upload");
-        print "Stage 18: Upload\n";
-        my $cmd = "bash <(curl -s https://codecov.io/bash) -f $cc_dir/app_total.info";
-        print "print: Not running: export CODECOV_TOKEN=<hidden>\n";
-        print "print: Not running: $cmd\n";
-        ci_fold_end();
-    }
+    if Args.stage_enabled[18]:
+        ci_fold_start("upload")
+        print("Stage 18: Upload")
+        cmd = "bash <(curl -s https://codecov.io/bash) -f " + cc_dir + "/app_total.info"
+        print("print: Not running: export CODECOV_TOKEN=<hidden>")
+        print("print: Not running: " + cmd)
+        ci_fold_end()
 
-    if ($Opt_Stages{19}) {
-        print "*-* All Finished *-*\n";
-        print "\n";
-        print "* See report in ${cc_dir}/html/index.html\n";
-        print "* Remember to make distclean && ./configure before working on non-coverage\n";
-    }
-}
+    if Args.stage_enabled[19]:
+        print("*-* All Finished *-*")
+        print("")
+        print("* See report in " + cc_dir + "/html/index.html")
+        print(
+            "* Remember to make distclean && ./configure before working on non-coverage"
+        )
 
-sub clone_sources {
-    my $cc_dir = shift;
-    my $excluded_lines = 0;
-    my $excluded_br_lines = 0;
-    foreach my $glob (@Source_Globs) {
-        foreach my $infile (glob $glob) {
-            $infile !~ m!^/!
-                or die "%Error: source globs should be relative not absolute filenames,";
-            my $outfile = $cc_dir."/".$infile;
-            (my $outpath = $outfile) =~ s!/[^/]*$!!;
-            mkpath($outpath);
-            my $fh = IO::File->new("<$infile") or die "%Error: $! $infile,";
-            my $ofh = IO::File->new(">$outfile") or die "%Error: $! $outfile,";
-            my $lineno = 0;
-            while (defined(my $line = $fh->getline)) {
-                $lineno++;
-                chomp $line;
-                if ($line =~ /LCOV_EXCL_LINE/) {
-                    $line .= " LCOV_EXCL_BR_LINE";
-                }
-                elsif ($line =~ /LCOV_EXCL_START/) {
-                    $line .= " LCOV_EXCL_BR_START";
-                }
-                elsif ($line =~ /LCOV_EXCL_STOP/) {
-                    $line .= " LCOV_EXCL_BR_STOP";
-                }
-                elsif ($line =~ /$Exclude_Line_Regexp/) {
-                    $line .= "  //code_coverage: // LCOV_EXCL_LINE LCOV_EXCL_BR_LINE";
-                    $excluded_lines++;
-                    $excluded_br_lines++;
-                    #print "$infile:$lineno: $line";
-                }
-                elsif ($line =~ /$Exclude_Branch_Regexp/) {
-                    $line .= "  //code_coverage: // LCOV_EXCL_BR_LINE";
-                    $excluded_br_lines++;
-                    #print "$infile:$lineno: $line";
-                }
-                $ofh->print("$line\n");
-            }
-        }
-    }
-    print "Number of source lines automatically LCOV_EXCL_LINE'ed: $excluded_lines\n";
-    print "Number of source lines automatically LCOV_EXCL_BR_LINE'ed: $excluded_br_lines\n";
-}
 
-sub cleanup_abs_paths_info {
-    my $cc_dir = shift;
-    my $infile = shift;
-    my $outfile = shift;
-    my $fh = IO::File->new("<$infile") or die "%Error: $! $infile,";
-    my @lines;
-    while (defined(my $line = $fh->getline)) {
-        if ($line =~ m!^SF:!) {
-            $line =~ s!$ENV{VERILATOR_ROOT}/!!;
-            $line =~ s!$cc_dir/!!;
-            $line =~ s!obj_dbg/verilog.y$!verilog.y!;
-            #print "Remaining SF: ",$line;
-        }
-        push @lines, $line;
-    }
-    my $ofh = IO::File->new(">$outfile") or die "%Error: $! $outfile,";
-    $ofh->print(@lines);
-}
+def clone_sources(cc_dir):
+    excluded_lines = 0
+    excluded_br_lines = 0
+    for globf in Source_Globs:
+        for infile in glob.glob(globf):
+            if re.match(r'^/', infile):
+                sys.exit(
+                    "%Error: source globs should be relative not absolute filenames, "
+                    + infile)
+            outfile = cc_dir + "/" + infile
+            outpath = re.sub(r'/[^/]*$', '', outfile, count=1)
+            os.makedirs(outpath, exist_ok=True)
+            with open(infile) as fh:
+                with open(outfile, "w") as ofh:
+                    lineno = 0
+                    for line in fh:
+                        lineno += 1
+                        line = line.rstrip()
+                        done = False
+                        if re.search(r'LCOV_EXCL_LINE', line):
+                            line += " LCOV_EXCL_BR_LINE"
+                            done = True
+                        elif re.search(r'LCOV_EXCL_START', line):
+                            line += " LCOV_EXCL_BR_START"
+                            done = True
+                        elif re.search(r'LCOV_EXCL_STOP', line):
+                            line += " LCOV_EXCL_BR_STOP"
+                            done = True
 
-sub cleanup_abs_paths_json {
-    my $cc_dir = shift;
-    my $infile = shift;
-    my $outfile = shift;
-    # Handcrafted cleanup, alternative would be to deserialize/serialize JSON
-    # But JSON::Parse not installed by default
-    # JSON::PP more likely to be installed, but slower
-    my $fh = IO::File->new("<$infile") or die "%Error: $! $infile,";
-    my @lines;
-    while (defined(my $line = $fh->getline)) {
-        $line =~ s!"$ENV{VERILATOR_ROOT}/!"!g;
-        $line =~ s!"$cc_dir/!"!g;
-        $line =~ s!obj_dbg/verilog.y$!verilog.y!g;
-        push @lines, $line;
-    }
-    my $ofh = IO::File->new(">$outfile") or die "%Error: $! $outfile,";
-    $ofh->print(@lines);
-}
+                        for regexp in Exclude_Line_Regexps:
+                            if done:
+                                break
+                            if re.search(regexp, line):
+                                #print("%s:%d: %s" % (infile, lineno, line)
+                                line += "  //code_coverage: // LCOV_EXCL_LINE LCOV_EXCL_BR_LINE"
+                                excluded_lines += 1
+                                excluded_br_lines += 1
+                                done = True
 
-#######################################################################
+                        for regexp in Exclude_Branch_Regexps:
+                            if done:
+                                break
+                            if re.search(regexp, line):
+                                #print("%s:%d: %s" % (infile, lineno, line)
+                                line += "  //code_coverage: // LCOV_EXCL_BR_LINE"
+                                excluded_br_lines += 1
+                                done = True
+
+                        ofh.write(line + "\n")
+    print("Number of source lines automatically LCOV_EXCL_LINE'ed: %d" %
+          excluded_lines)
+    print("Number of source lines automatically LCOV_EXCL_BR_LINE'ed: %d" %
+          excluded_br_lines)
+
+
+def cleanup_abs_paths_info(cc_dir, infile, outfile):
+    lines = []
+    with open(infile) as fh:
+        for line in fh:
+            if re.search(r'^SF:', line):
+                line = re.sub(os.environ['VERILATOR_ROOT'] + '/',
+                              '',
+                              line,
+                              count=1)
+                line = re.sub(cc_dir + '/', '', line, count=1)
+                line = re.sub(r'obj_dbg/verilog.y$', 'verilog.y', line)
+                #print("Remaining SF: "+line)
+            lines.append(line)
+
+    with open(outfile, "w") as ofh:
+        for line in lines:
+            ofh.write(line)
+
+
+def cleanup_abs_paths_json(cc_dir, infile, outfile):
+    # Handcrafted cleanup, alternative would be to deserialize/serialize JSON,
+    # but this is much faster
+    lines = []
+    with open(infile) as fh:
+        for line in fh:
+            line = re.sub('"' + os.environ['VERILATOR_ROOT'] + '/', '"', line)
+            line = re.sub('"' + cc_dir + '/', '"', line)
+            line = re.sub(r'obj_dbg/verilog.y$', 'verilog.y', line)
+            lines.append(line)
+
+    with open(outfile, "w") as ofh:
+        for line in lines:
+            ofh.write(line)
+
+
+######################################################################
 # .dat file callbacks
 
-sub exclude_branch_regexp {
-    $Exclude_Branch_Regexp = shift;
-}
-sub exclude_line_regexp {
-    $Exclude_Line_Regexp = shift;
-}
-sub remove_gcda_regexp {
-    $Remove_Gcda_Regexp = shift;
-}
-sub remove_source {
-    my @srcs = @_;
-    push @Remove_Sources, @srcs;
-}
-sub source_globs {
-    my @dirs = @_;
-    push @Source_Globs, @dirs;
-}
+
+def exclude_branch_regexp(*regexps):
+    Exclude_Branch_Regexps.extend(regexps)
+
+
+def exclude_line_regexp(*regexps):
+    Exclude_Line_Regexps.extend(regexps)
+
+
+def remove_gcda_regexp(*regexps):
+    Remove_Gcda_Regexps.extend(regexps)
+
+
+def remove_source(*sources):
+    Remove_Sources.extend(sources)
+
+
+def source_globs(*dirs):
+    Source_Globs.extend(dirs)
+
 
 #######################################################################
 
-sub run {
-    # Run a system command, check errors
-    my $command = shift;
-    print "\t$command\n";
-    system "$command";
-    my $status = $?;
-    ($status == 0) or die "%Error: Command Failed $command, $status, stopped";
-}
 
-our $_Ci_Action;
-sub ci_fold_start {
-    $_Ci_Action = shift;
-    print "::group::$_Ci_Action\n";
-}
-sub ci_fold_end {
-    print "::endgroup::\n";
-}
+def run(command):
+    # run a system command, check errors
+    print("\t%s" % command)
+    os.system(command)
+    status = subprocess.call(command, shell=True)
+    if status < 0:
+        raise Exception("%Error: Command failed " + command + ", stopped")
+
+
+def ci_fold_start(action):
+    print("::group::" + action)
+
+
+def ci_fold_end():
+    print("::endgroup::\n")
+
 
 #######################################################################
-__END__
+#######################################################################
 
-=pod
-
-=head1 NAME
-
-code_coverage - Build and collect Verilator coverage
-
-=head1 SYNOPSIS
+parser = argparse.ArgumentParser(
+    allow_abbrev=False,
+    formatter_class=argparse.RawDescriptionHelpFormatter,
+    description=
+    """code_coverage builds Verilator with C++ coverage support and runs
+tests with coverage enabled. This will rebuild the current object
+files. Run as:
 
   cd $VERILATOR_ROOT
-  nodist/code_coverage
-
-=head1 DESCRIPTION
-
-code_coverage builds Verilator with C++ coverage support and runs tests
-with coverage enabled.
-
-This will rebuild the current object files.
-
-=head1 ARGUMENTS
-
-=over 4
-
-=item --hashset I<hashset>
-
-Pass test hashset onto driver.pl test harness.
-
-=item --help
-
-Displays this message and program version and exits.
-
-=item --scenarios I<scenarios>
-
-Pass test scenarios onto driver.pl test harness.
-
-=item --stages I<stage>
-
-Runs a specific stage or range of stages (see the script).
-
-=item --no-stop
-
-Do not stop collecting data if tests fail.
-
-=item --test I<test_regress_test_name>
-
-Instead of normal regressions, run the specified test.  May be specified
-multiple times for multiple tests.
-
-=back
-
-=head1 DISTRIBUTION
-
-Copyright 2019-2020 by Wilson Snyder. This program is free software; you
+  nodist/code_coverage""",
+    epilog=
+    """Copyright 2019-2020 by Wilson Snyder. This program is free software; you
 can redistribute it and/or modify it under the terms of either the GNU
 Lesser General Public License Version 3 or the Perl Artistic License
 Version 2.0.
 
-SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0""")
 
-=head1 AUTHORS
+parser.add_argument('--debug', action='store_true', help='enable debug')
+parser.add_argument('--hashset',
+                    action='store',
+                    help='pass test hashset onto driver.pl test harness')
+parser.add_argument('--scenarios',
+                    action='store',
+                    help='pass test scenarios onto driver.pl test harness')
+parser.add_argument(
+    '--stages',
+    action='store',
+    help='runs a specific stage or range of stages (see the script)')
+parser.add_argument(
+    '--test',
+    action='append',
+    dest='tests',
+    default=[],
+    help=
+    'Instead of normal regressions, run the specified test(s), may be used multiple times'
+)
+parser.add_argument('--no-stop',
+                    dest='stop',
+                    action='store_false',
+                    help='do not stop collecting data if tests fail')
 
-Wilson Snyder <wsnyder@wsnyder.org>
+parser.set_defaults(stop=True)
+Args = parser.parse_args()
 
-=head1 SEE ALSO
+if True:
+    start = 0
+    end = 99
+    Args.stage_enabled = {}
+    if Args.stages:
+        match_one = re.match(r'^(\d+)$', Args.stages)
+        match_range = re.match(r'^(\d+)-(\d+)$', Args.stages)
+        match_to = re.match(r'^-(\d+)$', Args.stages)
+        match_from = re.match(r'^(\d+)-$', Args.stages)
+        if match_one:
+            start = end = int(match_one.group(1))
+        elif match_range:
+            start = int(match_range.group(1))
+            end = int(match_range.group(2))
+        elif match_to:
+            end = int(match_to.group(1))
+        elif match_from:
+            start = int(match_from.group(1))
+        else:
+            os.exit("%Error: --stages not understood: " + Args.stages)
+    for n in range(1, 100):
+        Args.stage_enabled[n] = False
+    for n in range(start, end + 1):
+        Args.stage_enabled[n] = True
 
-C<lcov>
-
-=cut
+test()
 
 ######################################################################
 ### Local Variables:
diff --git a/nodist/code_coverage.dat b/nodist/code_coverage.dat
index a3a276afa..0817ef51a 100644
--- a/nodist/code_coverage.dat
+++ b/nodist/code_coverage.dat
@@ -1,4 +1,4 @@
-# -*- Perl -*-
+# -*- Python -*-
 # DESCRIPTION: Verilator: Internal C++ code lcov control file
 #
 # Copyright 2019-2020 by Wilson Snyder. This program is free software; you
@@ -7,57 +7,56 @@
 # Version 2.0.
 # SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
 
-source_globs("src/*.cpp",
-             "src/*.h",
-             "src/*.l",
-             "src/*.y",
-             "src/obj_dbg/*.h",
-             "src/obj_dbg/*.cpp",
-             "include/*.c",
-             "include/*.cpp",
-             "include/*.h",
-             "include/*/*.h",
-             "include/*/*.cpp",
-             "include/*/*.c",
-    );
+source_globs("src/*.cpp")
+source_globs("src/*.h")
+source_globs("src/*.l")
+source_globs("src/*.y")
+source_globs("src/obj_dbg/*.h")
+source_globs("src/obj_dbg/*.cpp")
+source_globs("include/*.c")
+source_globs("include/*.cpp")
+source_globs("include/*.h")
+source_globs("include/*/*.h")
+source_globs("include/*/*.cpp")
+source_globs("include/*/*.c")
 
 # Note *'s are removed when using fastcov
-remove_source("/usr/*");
-remove_source("*/include/sysc/*");
-remove_source("*/V3ClkGater.cpp");
-remove_source("*/V3ClkGater.h");
-remove_source("*/V3GraphDfa.cpp");
-remove_source("*/V3GraphDfa.h");
-remove_source("*/V3Lexer_pregen.yy.cpp");
-remove_source("*/V3PreLex_pregen.yy.cpp");
-remove_source("*/verilog.c");
-remove_source("*include/gtkwave/*");
+remove_source("/usr/*")
+remove_source("*/include/sysc/*")
+remove_source("*/V3ClkGater.cpp")
+remove_source("*/V3ClkGater.h")
+remove_source("*/V3GraphDfa.cpp")
+remove_source("*/V3GraphDfa.h")
+remove_source("*/V3Lexer_pregen.yy.cpp")
+remove_source("*/V3PreLex_pregen.yy.cpp")
+remove_source("*/verilog.c")
+remove_source("*include/gtkwave/*")
 # Something wrong in generation, unfortunately as would like this
 #genhtml: ERROR: cannot read /svaha/wsnyder/SandBox/homecvs/v4/verilator/src/obj_dbg/verilog.y
-#remove_source("*/src/obj_dbg/verilog.y");
-remove_source("*test_regress/*");
-remove_source("*examples/*");
+#remove_source("*/src/obj_dbg/verilog.y")
+remove_source("*test_regress/*")
+remove_source("*examples/*")
 
 # Remove collected coverage on each little test main file
 # Would just be removed with remove_source in later step
-remove_gcda_regexp(qr!test_regress/.*/(Vt_|Vtop_).*\.gcda!);
+remove_gcda_regexp(r'test_regress/.*/(Vt_|Vtop_).*\.gcda')
 
 # Exclude line entirely, also excludes from function and branch coverage
-exclude_line_regexp(qr/(\bv3fatalSrc\b
-                    |\bfatalSrc\b
-                    |\bVL_UNCOVERABLE\b
-                    |\bVL_UNREACHABLE\b
-                    |\bVL_FATAL
-                    |\bUASSERT
-                    |\bNUM_ASSERT
-                    |\bERROR_RSVD_WORD
-                    |\bV3ERROR_NA
-                    |\bUINFO\b)/x);
+exclude_line_regexp(r'\bv3fatalSrc\b')
+exclude_line_regexp(r'\bfatalSrc\b')
+exclude_line_regexp(r'\bVL_UNCOVERABLE\b')
+exclude_line_regexp(r'\bVL_UNREACHABLE\b')
+exclude_line_regexp(r'\bVL_FATAL')
+exclude_line_regexp(r'\bUASSERT')
+exclude_line_regexp(r'\bNUM_ASSERT')
+exclude_line_regexp(r'\bERROR_RSVD_WORD')
+exclude_line_regexp(r'\bV3ERROR_NA')
+exclude_line_regexp(r'\bUINFO\b')
 
 # Exclude for branch coverage only
-exclude_branch_regexp(qr/(\bdebug\(\)
-                         |\bassert\(
-                         |\bBROKEN_RTK\(
-                         |\bSELF_CHECK)/x);
+exclude_branch_regexp(r'\bdebug\(\)')
+exclude_branch_regexp(r'\bassert\(')
+exclude_branch_regexp(r'\bBROKEN_RTK\(')
+exclude_branch_regexp(r'\bSELF_CHECK')
 
-1;
+True