MIR Serialization: Print MCSymbol operands.

This commit allows the MIR printer to print the MCSymbol machine operands.
Unfortunately they can't be parsed at this time. I will create a bug that will
track the fact that the MCSymbol operands can't be parsed yet.

llvm-svn: 245737
diff --git a/llvm/lib/CodeGen/MIRPrinter.cpp b/llvm/lib/CodeGen/MIRPrinter.cpp
index 4b4d7b4..aa3d193 100644
--- a/llvm/lib/CodeGen/MIRPrinter.cpp
+++ b/llvm/lib/CodeGen/MIRPrinter.cpp
@@ -27,6 +27,7 @@
 #include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/ModuleSlotTracker.h"
+#include "llvm/MC/MCSymbol.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/YAMLTraits.h"
@@ -826,14 +827,14 @@
   case MachineOperand::MO_Metadata:
     Op.getMetadata()->printAsOperand(OS, MST);
     break;
+  case MachineOperand::MO_MCSymbol:
+    OS << "<mcsymbol " << *Op.getMCSymbol() << ">";
+    break;
   case MachineOperand::MO_CFIIndex: {
     const auto &MMI = Op.getParent()->getParent()->getParent()->getMMI();
     print(MMI.getFrameInstructions()[Op.getCFIIndex()], TRI);
     break;
   }
-  default:
-    // TODO: Print the other machine operands.
-    llvm_unreachable("Can't print this machine operand at the moment");
   }
 }