diff --git a/llvm/lib/Target/AVR/HarvardCheck/HarvardCheck.cpp b/llvm/lib/Target/AVR/HarvardCheck/HarvardCheck.cpp
--- a/llvm/lib/Target/AVR/HarvardCheck/HarvardCheck.cpp
+++ b/llvm/lib/Target/AVR/HarvardCheck/HarvardCheck.cpp
@@ -6,10 +6,13 @@
 //
 //===----------------------------------------------------------------------===//
 ///
-/// \file Function pass to verify all functions are in program memory
+/// \file
+/// Function pass to verify all functions are in program memory
 ///
 /// Visits all functions in a module and reports those that are not in the
-/// program memory address space.
+/// program memory address space as defined by the targets DataLayout. This
+/// helps to find transformations that accidentially place functions in data
+/// space because they assume a von Neumann architecture.
 ///
 /// Usage:
 /// \code
@@ -17,7 +20,7 @@
 /// \endcode
 ///
 /// \param --harvard-abort-on-error
-/// \param --harvard-program-address-space N
+/// \param --harvard-program-address-space NUMBER
 ///
 //===----------------------------------------------------------------------===//
 
@@ -41,7 +44,8 @@
 
 namespace {
 
-struct HarvardCheck : FunctionPass {
+class HarvardCheck : public FunctionPass {
+public:
   static char ID;
   HarvardCheck() : FunctionPass(ID), ProgramAddressSpace(), ErrorCount() {}
 
@@ -69,7 +73,7 @@
 
   bool doFinalization(Module &) override {
     if (ErrorCount != 0 && AbortOnErrorOption) {
-      errs() << "not all functions are in program memory. Aborting\n";
+      errs() << "error: not all functions are in program memory. Aborting\n";
       exit(1);
     }
     return false;