diff --git a/utils/UpdateCMakeLists.pl b/utils/UpdateCMakeLists.pl
new file mode 100755
index 00000000000..94e69ce2556
--- /dev/null
+++ b/utils/UpdateCMakeLists.pl
@@ -0,0 +1,118 @@
+#!/usr/bin/env perl
+use strict;
+use File::Find;
+use File::Copy;
+use Digest::MD5;
+
+my @fileTypes = ("cpp", "c");
+my %dirFiles;
+my %dirCMake;
+
+sub GetFiles {
+  my $dir = shift;
+  my $x = $dirFiles{$dir};  
+  if (!defined $x) {
+    $x = [];
+    $dirFiles{$dir} = $x;
+  }  
+  return $x;
+}
+
+sub ProcessFile {
+  my $file = $_;
+  my $dir = $File::Find::dir;
+  # Record if a CMake file was found.
+  if ($file eq "CMakeLists.txt") {
+    $dirCMake{$dir} = $File::Find::name;
+    return 0;
+  }
+  # Grab the extension of the file.
+  $file =~ /\.([^.]+)$/;
+  my $ext = $1;
+  my $files;
+  foreach my $x (@fileTypes) {
+    if ($ext eq $x) {
+      if (!defined $files) {
+        $files = GetFiles($dir);
+      }
+      push @$files, $file;
+      return 0;
+    }
+  }
+  return 0;
+}
+
+sub EmitCMakeList {
+  my $dir = shift;
+  my $files = $dirFiles{$dir};
+  
+  if (!defined $files) {
+    return;
+  }
+  
+  foreach my $file (sort @$files) {
+    print OUT "  ";
+    print OUT $file;
+    print OUT "\n";
+  }  
+}
+
+sub UpdateCMake {
+  my $cmakeList = shift;
+  my $dir = shift;
+  my $cmakeListNew = $cmakeList . ".new";
+  open(IN, $cmakeList);
+  open(OUT, ">", $cmakeListNew);
+  my $foundLibrary = 0;
+  
+  while(<IN>) {
+    if (!$foundLibrary) {
+      print OUT $_;
+      if (/^add_clang_library\(/ || /^add_llvm_library\(/) {
+        $foundLibrary = 1;
+        EmitCMakeList($dir);
+      }
+    }
+    else {
+      if (/\)/) {
+        print OUT $_;
+        $foundLibrary = 0;
+      }
+    }
+  }
+
+  close(IN);
+  close(OUT);
+
+  open(FILE, $cmakeList) or
+    die("Cannot open $cmakeList when computing digest\n");
+  binmode FILE;
+  my $digestA = Digest::MD5->new->addfile(*FILE)->hexdigest;
+  close(FILE);
+    
+  open(FILE, $cmakeListNew) or
+    die("Cannot open $cmakeListNew when computing digest\n");
+  binmode FILE;
+  my $digestB = Digest::MD5->new->addfile(*FILE)->hexdigest;
+  close(FILE);
+  
+  if ($digestA != $digestB) {
+    move($cmakeListNew, $cmakeList);
+    return 1;    
+  }
+  
+  unlink($cmakeListNew);
+  return 0;
+}
+
+sub UpdateCMakeFiles {
+  foreach my $dir (sort keys %dirCMake) {
+    if (UpdateCMake($dirCMake{$dir}, $dir)) {
+      print "Updated: $dir\n";
+    }
+  }
+}
+
+find({ wanted => \&ProcessFile, follow => 1 }, '.');
+UpdateCMakeFiles();
+