cleanup-trace-events.pl: New

Simple script to drop unused events and fix up source file comments.
The next few commits put it to use.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

scripts/cleanup-trace-events.pl

@@ -0,0 +1,51 @@
+#!/usr/bin/perl
+# Copyright (C) 2013 Red Hat, Inc.
+#
+# Authors:
+#  Markus Armbruster <armbru@redhat.com>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or
+# later.  See the COPYING file in the top-level directory.
+
+# Usage: cleanup-trace-events.pl trace-events
+#
+# Print cleaned up trace-events to standard output.
+
+use warnings;
+use strict;
+
+my $buf = '';
+my %seen = ();
+
+sub out {
+    print $buf;
+    $buf = '';
+    %seen = ();
+}
+
+while (<>) {
+    if (/^(disable )?([a-z_0-9]+)\(/) {
+        open GREP, '-|', 'git', 'grep', '-l', "trace_$2"
+            or die "run git grep: $!";
+        my $fname;
+        while ($fname = <GREP>) {
+            chomp $fname;
+            next if $seen{$fname} || $fname eq 'trace-events';
+            $seen{$fname} = 1;
+            $buf = "# $fname\n" . $buf;
+        }
+        unless (close GREP) {
+            die "close git grep: $!"
+                if $!;
+            next;
+        }
+    } elsif (/^# ([^ ]*\.[ch])$/) {
+        out;
+        next;
+    } elsif (!/^#|^$/) {
+        warn "unintelligible line";
+    }
+    $buf .= $_;
+}
+
+out;