Remove unneeded use of #undef DEBUG_TYPE. NFC

Where is is needed (at the end of headers that define it), be
consistent about its use.

Also fix a few header guards that I found in the process.

Differential Revision: https://reviews.llvm.org/D34916

llvm-svn: 307840
diff --git a/llvm/lib/Transforms/Instrumentation/CFGMST.h b/llvm/lib/Transforms/Instrumentation/CFGMST.h
index 3802f9f..16e2e6b 100644
--- a/llvm/lib/Transforms/Instrumentation/CFGMST.h
+++ b/llvm/lib/Transforms/Instrumentation/CFGMST.h
@@ -12,6 +12,9 @@
 //
 //===----------------------------------------------------------------------===//
 
+#ifndef LLVM_LIB_TRANSFORMS_INSTRUMENTATION_CFGMST_H
+#define LLVM_LIB_TRANSFORMS_INSTRUMENTATION_CFGMST_H
+
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Analysis/BlockFrequencyInfo.h"
@@ -24,10 +27,10 @@
 #include <utility>
 #include <vector>
 
-namespace llvm {
-
 #define DEBUG_TYPE "cfgmst"
 
+namespace llvm {
+
 /// \brief An union-find based Minimum Spanning Tree for CFG
 ///
 /// Implements a Union-find algorithm to compute Minimum Spanning Tree
@@ -220,5 +223,8 @@
   }
 };
 
-#undef DEBUG_TYPE // "cfgmst"
 } // end namespace llvm
+
+#undef DEBUG_TYPE // "cfgmst"
+
+#endif // LLVM_LIB_TRANSFORMS_INSTRUMENTATION_CFGMST_H