Index: cmake/modules/CMakeLists.txt
===================================================================
--- cmake/modules/CMakeLists.txt
+++ cmake/modules/CMakeLists.txt
@@ -30,10 +30,10 @@
 # Generate ClangConfig.cmake for the install tree.
 set(CLANG_CONFIG_CODE "
 # Compute the installation prefix from this LLVMConfig.cmake file location.
-get_filename_component(CLANG_INSTALL_PREFIX \"\${CMAKE_CURRENT_LIST_FILE}\" PATH)")
+get_filename_component(CLANG_INSTALL_PREFIX \"\${CMAKE_CURRENT_LIST_FILE}\" REALPATH)")
 # Construct the proper number of get_filename_component(... PATH)
 # calls to compute the installation prefix.
-string(REGEX REPLACE "/" ";" _count "${CLANG_INSTALL_PACKAGE_DIR}")
+string(REGEX REPLACE "/" ";" _count "prefix/${CLANG_INSTALL_PACKAGE_DIR}")
 foreach(p ${_count})
   set(CLANG_CONFIG_CODE "${CLANG_CONFIG_CODE}
 get_filename_component(CLANG_INSTALL_PREFIX \"\${CLANG_INSTALL_PREFIX}\" PATH)")