llvm-profdata: Use the Profile library, implement show and generate

This replaces the llvm-profdata tool with a version that uses the
recently introduced Profile library. The new tool has the ability to
generate and summarize profdata files as well as merging them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203704 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/LineIterator.h

@@ -56,6 +56,7 @@ public:
 
   /// \brief Get the current line as a \c StringRef.
   StringRef operator*() const { return CurrentLine; }
+  const StringRef *operator->() const { return &CurrentLine; }
 
   friend bool operator==(const line_iterator &LHS, const line_iterator &RHS) {
     return LHS.Buffer == RHS.Buffer &&