diff --git a/llvm/cmake/modules/AddLLVM.cmake b/llvm/cmake/modules/AddLLVM.cmake
--- a/llvm/cmake/modules/AddLLVM.cmake
+++ b/llvm/cmake/modules/AddLLVM.cmake
@@ -363,26 +363,39 @@
     ""
     ${ARGN})
 
+  # Set from arguments.
   if (NOT DEFINED ARG_VERSION_MAJOR)
     set(ARG_VERSION_MAJOR ${LLVM_VERSION_MAJOR})
   endif()
-
   if (NOT DEFINED ARG_VERSION_MINOR)
     set(ARG_VERSION_MINOR ${LLVM_VERSION_MINOR})
   endif()
-
   if (NOT DEFINED ARG_VERSION_PATCHLEVEL)
     set(ARG_VERSION_PATCHLEVEL ${LLVM_VERSION_PATCH})
   endif()
-
   if (NOT DEFINED ARG_VERSION_STRING)
     set(ARG_VERSION_STRING ${PACKAGE_VERSION})
   endif()
-
   if (NOT DEFINED ARG_PRODUCT_NAME)
     set(ARG_PRODUCT_NAME "LLVM")
   endif()
 
+  # Make sure to default integer fields in the case that version information
+  # is not defaulted above (can happen in out of tree projects). Leaving these
+  # blank causes the resource compiler to fail with obscure errors.
+  if (NOT ARG_VERSION_MAJOR)
+    set(ARG_VERSION_MAJOR 0)
+  endif()
+  if (NOT ARG_VERSION_MINOR)
+    set(ARG_VERSION_MINOR 0)
+  endif()
+  if (NOT ARG_VERSION_PATCHLEVEL)
+    set(ARG_VERSION_PATCHLEVEL 0)
+  endif()
+  if (NOT ARG_VERSION_STRING)
+    set(ARG_VERSION_STRING 0)
+  endif()
+
   set_property(SOURCE ${resource_file}
                PROPERTY COMPILE_FLAGS /nologo)
   set_property(SOURCE ${resource_file}