[llvm-tapi-diff] Wrap empty string around StringLiteral NFC

This prevents invalid implicit conversation which caused buildbot
failure.

diff --git a/llvm/tools/llvm-tapi-diff/DiffEngine.cpp b/llvm/tools/llvm-tapi-diff/DiffEngine.cpp
index 481d35f..ff60d52 100644 (file)
--- a/llvm/tools/llvm-tapi-diff/DiffEngine.cpp
+++ b/llvm/tools/llvm-tapi-diff/DiffEngine.cpp
@@ -63,7 +63,7 @@ DiffScalarVal<bool, AD_Diff_Scalar_Bool>::print(raw_ostream &OS,
 StringLiteral SymScalar::getSymbolNamePrefix(MachO::SymbolKind Kind) {
   switch (Kind) {
   case MachO::SymbolKind::GlobalSymbol:
-    return "";
+    return StringLiteral("");
   case MachO::SymbolKind::ObjectiveCClass:
     return ObjC2MetaClassNamePrefix;
   case MachO::SymbolKind ::ObjectiveCClassEHType: