Add tools/parseTimings.pl.

A script to help pin down which modules take the most time
and memory to compile.

tools/parseTimings.pl

@@ -0,0 +1,33 @@
+#!/usr/bin/env perl
+
+# Breaks down compilation time and memory usage by module.
+# To use this script, do
+#
+# stack clean
+# stack build --ghc-options='-dshow-passes' 2>output.txt
+# perl parseTimings.pl output.txt
+
+while (<>) {
+  if (/!!! (.*) \[(.*)\]: finished in (.*) milliseconds, allocated (.*) megabytes/) {
+      $phase = $1;
+      $module = $2;
+      $milliseconds = $3;
+      $megabytes = $4;
+      if (!$timings{$module}) {
+        $timings{$module} = {'milliseconds' => 0, 'megabytes' => 0};
+      };
+      $timings{$module}{'milliseconds'} += $milliseconds;
+      $timings{$module}{'megabytes'} += $megabytes;
+    }
+  }
+  printf("%10s %10s %s\n", "Time (ms)", "Alloc (Mb)", "LOC", "Module");
+  for (keys %timings) {
+    $path = $_;
+    $path =~ s/\./\//g;
+    $path = "src/$path.hs";
+    $loc = `wc -l $path 2>/dev/null`;
+    if ($loc) {
+      $loc =~ s/^\s*(\d+).*/\1/;
+      printf("%10d %10d %6d %s\n", $timings{$_}{'milliseconds'}, $timings{$_}{'megabytes'}, $loc, $_);
+    }
+}