Reported by Coverity:
AUTO_CAUSES_COPY
Unnecessary object copies can affect performance
1. Inside "ODRHash.cpp" file, in clang::ODRHash::AddCXXRecordDecl(clang::CXXRecordDecl const *): Using the auto keyword without an & causes the copy of an object of type CXXBaseSpecifier.
2. Inside "Tokens.cpp" file, in clang::syntax::TokenBuffer::dumpForTests[abi:cxx11](): Using the auto keyword without an & causes the copy of an object of type DenseMapPair.
3. Inside "TargetID.cpp" file, in clang::getCanonicalTargetID[abi:cxx11](llvm::StringRef, llvm::StringMap<bool, llvm::MallocAllocator> const &): Using the auto keyword without an & causes the copy of an object of type pair.
Reviewed By: tahonermann, aaron.ballman
Differential Revision: https://reviews.llvm.org/D148639