diff --git a/CMakeLists.txt b/CMakeLists.txt
index 090cfa352078..624b7c9f3400 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -38,12 +38,26 @@ if(CLANG_BUILT_STANDALONE)
   find_package(LLVM REQUIRED HINTS "${LLVM_CMAKE_DIR}")
   list(APPEND CMAKE_MODULE_PATH "${LLVM_DIR}")
 
-  # Turn into CACHE PATHs for overwritting
-  set(LLVM_INCLUDE_DIRS ${LLVM_INCLUDE_DIRS} CACHE PATH "Path to llvm/include and any other header dirs needed")
-  set(LLVM_BINARY_DIR "${LLVM_BINARY_DIR}" CACHE PATH "Path to LLVM build tree")
-  set(LLVM_MAIN_SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../llvm" CACHE PATH "Path to LLVM source tree")
-  set(LLVM_TOOLS_BINARY_DIR "${LLVM_TOOLS_BINARY_DIR}" CACHE PATH "Path to llvm/bin")
-  set(LLVM_LIBRARY_DIR "${LLVM_LIBRARY_DIR}" CACHE PATH "Path to llvm/lib")
+  # We can't check LLVM_CONFIG here, because find_package(LLVM ...) also sets
+  # LLVM_CONFIG.
+  if (NOT LLVM_CONFIG_FOUND)
+    # Pull values from LLVMConfig.cmake.  We can drop this once the llvm-config
+    # path is removed.
+    set(INCLUDE_DIRS ${LLVM_INCLUDE_DIRS})
+    set(LLVM_OBJ_DIR "${LLVM_BINARY_DIR}")
+    # N.B. this is just a default value, the CACHE PATHs below can be overriden.
+    set(MAIN_SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../llvm")
+    set(TOOLS_BINARY_DIR "${LLVM_TOOLS_BINARY_DIR}")
+    set(LIBRARY_DIR "${LLVM_LIBRARY_DIR}")
+  else()
+    set(INCLUDE_DIRS "${LLVM_BINARY_DIR}/include" "${MAIN_INCLUDE_DIR}")
+  endif()
+
+  set(LLVM_INCLUDE_DIRS ${INCLUDE_DIRS} CACHE PATH "Path to llvm/include and any other header dirs needed")
+  set(LLVM_BINARY_DIR "${LLVM_OBJ_ROOT}" CACHE PATH "Path to LLVM build tree")
+  set(LLVM_MAIN_SRC_DIR "${MAIN_SRC_DIR}" CACHE PATH "Path to LLVM source tree")
+  set(LLVM_TOOLS_BINARY_DIR "${TOOLS_BINARY_DIR}" CACHE PATH "Path to llvm/bin")
+  set(LLVM_LIBRARY_DIR "${LIBRARY_DIR}" CACHE PATH "Path to llvm/lib")
 
   find_program(LLVM_TABLEGEN_EXE "llvm-tblgen" ${LLVM_TOOLS_BINARY_DIR}
     NO_DEFAULT_PATH)
diff --git a/cmake/modules/AddClang.cmake b/cmake/modules/AddClang.cmake
index 75b0080f6715..c895b884cd27 100644
--- a/cmake/modules/AddClang.cmake
+++ b/cmake/modules/AddClang.cmake
@@ -119,8 +119,8 @@ macro(add_clang_library name)
         install(TARGETS ${lib}
           COMPONENT ${lib}
           ${export_to_clangtargets}
-          LIBRARY DESTINATION lib${LLVM_LIBDIR_SUFFIX}
-          ARCHIVE DESTINATION lib${LLVM_LIBDIR_SUFFIX}
+          LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX}"
+          ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX}"
           RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
 
         if (NOT LLVM_ENABLE_IDE)
diff --git a/lib/Headers/CMakeLists.txt b/lib/Headers/CMakeLists.txt
index bb9a11eabbef..e2de91c65fbb 100644
--- a/lib/Headers/CMakeLists.txt
+++ b/lib/Headers/CMakeLists.txt
@@ -437,7 +437,7 @@ add_header_target("openmp-resource-headers" ${openmp_wrapper_files})
 add_header_target("windows-resource-headers" ${windows_only_files})
 add_header_target("utility-resource-headers" ${utility_files})
 
-set(header_install_dir lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION_MAJOR}/include)
+set(header_install_dir ${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION_MAJOR}/include)
 
 #############################################################
 # Install rules for the catch-all clang-resource-headers target
diff --git a/tools/libclang/CMakeLists.txt b/tools/libclang/CMakeLists.txt
index 4f23065a2472..6a0f55991e24 100644
--- a/tools/libclang/CMakeLists.txt
+++ b/tools/libclang/CMakeLists.txt
@@ -234,7 +234,7 @@ foreach(PythonVersion ${CLANG_PYTHON_BINDINGS_VERSIONS})
           COMPONENT
             libclang-python-bindings
           DESTINATION
-            "lib${LLVM_LIBDIR_SUFFIX}/python${PythonVersion}/site-packages")
+            "${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX}/python${PythonVersion}/site-packages")
 endforeach()
 if(NOT LLVM_ENABLE_IDE)
   add_custom_target(libclang-python-bindings)
diff --git a/tools/scan-build-py/CMakeLists.txt b/tools/scan-build-py/CMakeLists.txt
index 3aca22c0b0a8..3115353e3fe3 100644
--- a/tools/scan-build-py/CMakeLists.txt
+++ b/tools/scan-build-py/CMakeLists.txt
@@ -88,7 +88,7 @@ foreach(lib ${LibScanbuild})
                      DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/lib/libscanbuild/${lib})
   list(APPEND Depends ${CMAKE_BINARY_DIR}/lib/libscanbuild/${lib})
   install(FILES lib/libscanbuild/${lib}
-          DESTINATION lib${CLANG_LIBDIR_SUFFIX}/libscanbuild
+          DESTINATION "${CMAKE_INSTALL_LIBDIR}/libscanbuild"
           COMPONENT scan-build-py)
 endforeach()
 
@@ -106,7 +106,7 @@ foreach(resource ${LibScanbuildResources})
                      DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/lib/libscanbuild/resources/${resource})
   list(APPEND Depends ${CMAKE_BINARY_DIR}/lib/libscanbuild/resources/${resource})
   install(FILES lib/libscanbuild/resources/${resource}
-          DESTINATION lib${CLANG_LIBDIR_SUFFIX}/libscanbuild/resources
+          DESTINATION "${CMAKE_INSTALL_LIBDIR}/libscanbuild/resources"
           COMPONENT scan-build-py)
 endforeach()
 
@@ -122,7 +122,7 @@ foreach(lib ${LibEar})
                      DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/lib/libear/${lib})
   list(APPEND Depends ${CMAKE_BINARY_DIR}/lib/libear/${lib})
   install(FILES lib/libear/${lib}
-          DESTINATION lib${CLANG_LIBDIR_SUFFIX}/libear
+          DESTINATION "${CMAKE_INSTALL_LIBDIR}/libear"
           COMPONENT scan-build-py)
 endforeach()