[MIR] Add hasWinCFI field

[ssijaric]

Summary

Adding hasWinCFI field so that I can add a MIR test to https://reviews.llvm.org/D50166.

[ssijaric]

Add hasWinCFI to MIRPrinter as well, now that HasWinCFI is a plain bool.

[efriedma]

LGTM

llvm/trunk/include/llvm/CodeGen/MIRYamlMapping.h

struct MachineFunction {
   bool ExposesReturnsTwice = false;
   // GISel MachineFunctionProperties.
   bool Legalized = false;
   bool RegBankSelected = false;
   bool Selected = false;
   bool FailedISel = false;
   // Register information
   bool TracksRegLiveness = false;
+  bool HasWinCFI = false;
   std::vector<VirtualRegisterDefinition> VirtualRegisters;
   std::vector<MachineFunctionLiveIn> LiveIns;
   Optional<std::vector<FlowStringValue>> CalleeSavedRegisters;
   // TODO: Serialize the various register masks.
   // Frame information
   MachineFrameInfo FrameInfo;
   std::vector<FixedMachineStackObject> FixedStackObjects;
   std::vector<MachineStackObject> StackObjects;
   std::vector<MachineConstantPoolValue> Constants; /// Constant pool.
   MachineJumpTable JumpTableInfo;
   BlockStringValue Body;
 };
 
 template <> struct MappingTraits<MachineFunction> {
   static void mapping(IO &YamlIO, MachineFunction &MF) {
     YamlIO.mapRequired("name", MF.Name);
     YamlIO.mapOptional("alignment", MF.Alignment, (unsigned)0);
     YamlIO.mapOptional("exposesReturnsTwice", MF.ExposesReturnsTwice, false);
     YamlIO.mapOptional("legalized", MF.Legalized, false);
     YamlIO.mapOptional("regBankSelected", MF.RegBankSelected, false);
     YamlIO.mapOptional("selected", MF.Selected, false);
     YamlIO.mapOptional("failedISel", MF.FailedISel, false);
     YamlIO.mapOptional("tracksRegLiveness", MF.TracksRegLiveness, false);
+    YamlIO.mapOptional("hasWinCFI", MF.HasWinCFI, false);
     YamlIO.mapOptional("registers", MF.VirtualRegisters,
                        std::vector<VirtualRegisterDefinition>());
     YamlIO.mapOptional("liveins", MF.LiveIns,
                        std::vector<MachineFunctionLiveIn>());
     YamlIO.mapOptional("calleeSavedRegisters", MF.CalleeSavedRegisters,
                        Optional<std::vector<FlowStringValue>>());
     YamlIO.mapOptional("frameInfo", MF.FrameInfo, MachineFrameInfo());
     YamlIO.mapOptional("fixedStack", MF.FixedStackObjects,

llvm/trunk/lib/CodeGen/MIRParser/MIRParser.cpp

 MIRParserImpl::initializeMachineFunction(const yaml::MachineFunction &YamlMF,
                                          MachineFunction &MF) {
   // TODO: Recreate the machine function.
   initNames2RegClasses(MF);
   initNames2RegBanks(MF);
   if (YamlMF.Alignment)
     MF.setAlignment(YamlMF.Alignment);
   MF.setExposesReturnsTwice(YamlMF.ExposesReturnsTwice);
+  MF.setHasWinCFI(YamlMF.HasWinCFI);
 
   if (YamlMF.Legalized)
     MF.getProperties().set(MachineFunctionProperties::Property::Legalized);
   if (YamlMF.RegBankSelected)
     MF.getProperties().set(
         MachineFunctionProperties::Property::RegBankSelected);
   if (YamlMF.Selected)
     MF.getProperties().set(MachineFunctionProperties::Property::Selected);

llvm/trunk/lib/CodeGen/MIRPrinter.cpp

 
 void MIRPrinter::print(const MachineFunction &MF) {
   initRegisterMaskIds(MF);
 
   yaml::MachineFunction YamlMF;
   YamlMF.Name = MF.getName();
   YamlMF.Alignment = MF.getAlignment();
   YamlMF.ExposesReturnsTwice = MF.exposesReturnsTwice();
+  YamlMF.HasWinCFI = MF.hasWinCFI();
 
   YamlMF.Legalized = MF.getProperties().hasProperty(
       MachineFunctionProperties::Property::Legalized);
   YamlMF.RegBankSelected = MF.getProperties().hasProperty(
       MachineFunctionProperties::Property::RegBankSelected);
   YamlMF.Selected = MF.getProperties().hasProperty(
       MachineFunctionProperties::Property::Selected);
   YamlMF.FailedISel = MF.getProperties().hasProperty(