Avoid implicit string construction.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@112820 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Serialization/ASTWriter.h b/include/clang/Serialization/ASTWriter.h
index b8bff27..426fc47 100644
--- a/include/clang/Serialization/ASTWriter.h
+++ b/include/clang/Serialization/ASTWriter.h
@@ -424,7 +424,7 @@
                         unsigned NumBaseOrMembers, RecordData &Record);
 
   /// \brief Add a string to the given record.
-  void AddString(const std::string &Str, RecordData &Record);
+  void AddString(llvm::StringRef Str, RecordData &Record);
 
   /// \brief Mark a namespace as needing an update.
   void AddUpdatedNamespace(const NamespaceDecl *NS) {
diff --git a/lib/Serialization/ASTWriter.cpp b/lib/Serialization/ASTWriter.cpp
index efc7da7..3b6b218 100644
--- a/lib/Serialization/ASTWriter.cpp
+++ b/lib/Serialization/ASTWriter.cpp
@@ -2165,7 +2165,7 @@
   Stream.EmitRecord(DECL_ATTR, Record);
 }
 
-void ASTWriter::AddString(const std::string &Str, RecordData &Record) {
+void ASTWriter::AddString(llvm::StringRef Str, RecordData &Record) {
   Record.push_back(Str.size());
   Record.insert(Record.end(), Str.begin(), Str.end());
 }