Pass StringRef by value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86251 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCContext.cpp b/lib/MC/MCContext.cpp
index 09479c5..45d2c02 100644
--- a/lib/MC/MCContext.cpp
+++ b/lib/MC/MCContext.cpp
@@ -23,7 +23,7 @@
   // we don't need to free them here.
 }
 
-MCSymbol *MCContext::CreateSymbol(const StringRef &Name) {
+MCSymbol *MCContext::CreateSymbol(StringRef Name) {
   assert(Name[0] != '\0' && "Normal symbols cannot be unnamed!");
 
   // Create and bind the symbol, and ensure that names are unique.
@@ -32,7 +32,7 @@
   return Entry = new (*this) MCSymbol(Name, false);
 }
 
-MCSymbol *MCContext::GetOrCreateSymbol(const StringRef &Name) {
+MCSymbol *MCContext::GetOrCreateSymbol(StringRef Name) {
   MCSymbol *&Entry = Symbols[Name];
   if (Entry) return Entry;
 
@@ -46,7 +46,7 @@
 }
 
 
-MCSymbol *MCContext::CreateTemporarySymbol(const StringRef &Name) {
+MCSymbol *MCContext::CreateTemporarySymbol(StringRef Name) {
   // If unnamed, just create a symbol.
   if (Name.empty())
     new (*this) MCSymbol("", true);
@@ -57,6 +57,6 @@
   return Entry = new (*this) MCSymbol(Name, true);
 }
 
-MCSymbol *MCContext::LookupSymbol(const StringRef &Name) const {
+MCSymbol *MCContext::LookupSymbol(StringRef Name) const {
   return Symbols.lookup(Name);
 }