Previously, parsing capability of the .debug_frame section was added

to lib/DebugInfo, with dumping in llvm-dwarfdump. This patch adds
initial ability to parse and dump CFA instructions contained in
entries.

To keep it manageable, the patch omits some more advanced capabilities
(accounted in TODOs):

* Parsing of instructions with BLOCK arguments (expression lists)
* Dumping of actual instruction arguments (currently only names are
dumped). This is quite tricky since the dumper has to effectively
"interpret" the instructions.

llvm-svn: 175820

llvm/lib/Support/Dwarf.cpp

@@ -688,6 +688,7 @@ const char *llvm::dwarf::MacinfoString(unsigned Encoding) {
 /// encodings.
 const char *llvm::dwarf::CallFrameString(unsigned Encoding) {
   switch (Encoding) {
+  case DW_CFA_nop:                       return "DW_CFA_nop";
   case DW_CFA_advance_loc:               return "DW_CFA_advance_loc";
   case DW_CFA_offset:                    return "DW_CFA_offset";
   case DW_CFA_restore:                   return "DW_CFA_restore";