[AsmPrinter] Don't pass Twine by value. NFC

Author: topperc

llvm/include/llvm/CodeGen/AsmPrinter.h

@@ -632,7 +632,7 @@ class AsmPrinter : public MachineFunctionPass {
                                          StringRef Suffix) const;
 
   /// Return the MCSymbol for the specified ExternalSymbol.
-  MCSymbol *GetExternalSymbolSymbol(Twine Sym) const;
+  MCSymbol *GetExternalSymbolSymbol(const Twine &Sym) const;
 
   /// Return the symbol for the specified jump table entry.
   MCSymbol *GetJTISymbol(unsigned JTID, bool isLinkerPrivate = false) const;

llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -4142,7 +4142,7 @@ MCSymbol *AsmPrinter::getSymbolWithGlobalValueBase(const GlobalValue *GV,
 }
 
 /// Return the MCSymbol for the specified ExternalSymbol.
-MCSymbol *AsmPrinter::GetExternalSymbolSymbol(Twine Sym) const {
+MCSymbol *AsmPrinter::GetExternalSymbolSymbol(const Twine &Sym) const {
   SmallString<60> NameStr;
   Mangler::getNameWithPrefix(NameStr, Sym, getDataLayout());
   return OutContext.getOrCreateSymbol(NameStr);