Fix nulltpr typo in comment

[iliya-diyachkov]

Summary

The patch fixes the typo "nulltpr", accidentally found in comments.

[iliya-diyachkov]

Thanks. Please commit it, I don't have permissions to push yet.
Ilia Diachkov <[e-mail]>

llvm/include/llvm/Target/TargetLoweringObjectFile.h

public:
   /// Targets that have a special convention for their symbols could use
   /// this hook to return a specialized symbol.
   virtual MCSymbol *getTargetSymbol(const GlobalValue *GV,
                                     const TargetMachine &TM) const {
     return nullptr;
   }
 
   /// If supported, return the function entry point symbol.
-  /// Otherwise, returns nulltpr.
+  /// Otherwise, returns nullptr.
   /// Func must be a function or an alias which has a function as base object.
   virtual MCSymbol *getFunctionEntryPointSymbol(const GlobalValue *Func,
                                                 const TargetMachine &TM) const {
     return nullptr;
   }
 
 protected:
   virtual MCSection *SelectSectionForGlobal(const GlobalObject *GO,
                                             SectionKind Kind,
                                             const TargetMachine &TM) const = 0;
 };
 
 } // end namespace llvm
 
 #endif // LLVM_TARGET_TARGETLOWERINGOBJECTFILE_H

llvm/lib/MC/MCWin64EH.cpp

static void ARM64EmitUnwindCode(MCStreamer &streamer, const MCSymbol *begin,
   case Win64EH::UOP_ClearUnwoundToCall:
     b = 0xEC;
     streamer.emitInt8(b);
     break;
   }
 }
 
 // Returns the epilog symbol of an epilog with the exact same unwind code
-// sequence, if it exists.  Otherwise, returns nulltpr.
+// sequence, if it exists.  Otherwise, returns nullptr.
 // EpilogInstrs - Unwind codes for the current epilog.
 // Epilogs - Epilogs that potentialy match the current epilog.
 static MCSymbol*
 FindMatchingEpilog(const std::vector<WinEH::Instruction>& EpilogInstrs,
                    const std::vector<MCSymbol *>& Epilogs,
                    const WinEH::FrameInfo *info) {
   for (auto *EpilogStart : Epilogs) {
     auto InstrsIter = info->EpilogMap.find(EpilogStart);