--- a/llvm/tools/llvm-shlib/CMakeLists.txt
+++ b/llvm/tools/llvm-shlib/CMakeLists.txt
@@ -36,7 +36,10 @@ endif()

 add_llvm_library(LLVM SHARED DISABLE_LLVM_LINK_LLVM_DYLIB SONAME ${SOURCES})

+if(LIB_NAMES)
 list(REMOVE_DUPLICATES LIB_NAMES)
+endif()
+
 if(("${CMAKE_SYSTEM_NAME}" STREQUAL "Linux") OR (MINGW) OR (HAIKU)
    OR ("${CMAKE_SYSTEM_NAME}" STREQUAL "FreeBSD")
    OR ("${CMAKE_SYSTEM_NAME}" STREQUAL "OpenBSD")