diff --git a/cmake/modules/LLVMProcessSources.cmake b/cmake/modules/LLVMProcessSources.cmake
index 4ad97575071..2d88abfd752 100644
--- a/cmake/modules/LLVMProcessSources.cmake
+++ b/cmake/modules/LLVMProcessSources.cmake
@@ -1,4 +1,5 @@
 include(AddFileDependencies)
+include(CMakeParseArguments)
 
 function(llvm_replace_compiler_option var old new)
   # Replaces a compiler option or switch `old' in `var' by `new'.