commit 28e665fa054d62d4e2c777774cc83dea533dfe6e
Author: John Ericson <John.Ericson@Obsidian.Systems>
Date:   Sun Jan 16 05:52:22 2022 +0000

    [cmake] Slight fix ups to make robust to the full range of GNUInstallDirs
    
    See https://cmake.org/cmake/help/v3.14/module/GNUInstallDirs.html#result-variables for `CMAKE_INSTALL_FULL_*`
    
    Reviewed By: sebastian-ne
    
    Differential Revision: https://reviews.llvm.org/D130545

diff --git b/clang/tools/clang-linker-wrapper/CMakeLists.txt a/clang/tools/clang-linker-wrapper/CMakeLists.txt
index 88c19cad7b53..60392c7d901f 100644
--- b/clang/tools/clang-linker-wrapper/CMakeLists.txt
+++ a/clang/tools/clang-linker-wrapper/CMakeLists.txt
@@ -1,5 +1,3 @@
-include(GNUInstallDirs)
-
 set(LLVM_LINK_COMPONENTS 
   ${LLVM_TARGETS_TO_BUILD}
   BitWriter
@@ -44,4 +42,4 @@ target_link_libraries(clang-linker-wrapper
   ${CLANG_LINKER_WRAPPER_LIB_DEPS}
   )
 
-install(TARGETS clang-linker-wrapper RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
+install(TARGETS clang-linker-wrapper RUNTIME DESTINATION bin)
diff --git b/llvm-libgcc/lib/CMakeLists.txt a/llvm-libgcc/lib/CMakeLists.txt
index d895a21554b0..652af46db4cb 100644
--- b/llvm-libgcc/lib/CMakeLists.txt
+++ a/llvm-libgcc/lib/CMakeLists.txt
@@ -1,6 +1,5 @@
 include(CheckLibraryExists)
 include(GNUInstallDirs)
-include(ExtendPath)
 
 string(REPLACE "-Wl,-z,defs" "" CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS}")
 
@@ -42,13 +41,13 @@ target_link_libraries(libgcc_s PRIVATE
   c
 )
 
-extend_path(LLVM_LIBGCC_LIBUNWIND_STATIC_ROOT "${CMAKE_INSTALL_PREFIX}" "${LIBUNWIND_INSTALL_LIBRARY_DIR}")
+get_filename_component(LLVM_LIBGCC_LIBUNWIND_STATIC_ROOT "${CMAKE_INSTALL_PREFIX}/${LIBUNWIND_INSTALL_LIBRARY_DIR}" ABSOLUTE)
 #string(REPLACE "${CMAKE_INSTALL_FULL_LIBDIR}/" "" LLVM_LIBGCC_LIBUNWIND_STATIC_ROOT "${LLVM_LIBGCC_LIBUNWIND_STATIC_ROOT}")
 
 install(TARGETS libgcc_s
         LIBRARY DESTINATION "${LLVM_LIBGCC_LIBUNWIND_STATIC_ROOT}" COMPONENT unwind
         ARCHIVE DESTINATION "${LLVM_LIBGCC_LIBUNWIND_STATIC_ROOT}" COMPONENT unwind
-        RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}" COMPONENT unwind)
+        RUNTIME DESTINATION bin COMPONENT unwind)
 
 get_compiler_rt_install_dir(${LLVM_LIBGCC_TARGET_ARCH} install_dir_builtins)
 string(REGEX REPLACE "^lib/" "" install_dir_builtins "${install_dir_builtins}")
diff --git b/llvm/cmake/modules/CMakeLists.txt a/llvm/cmake/modules/CMakeLists.txt
index d4b0ab959148..25c9b790b80b 100644
--- b/llvm/cmake/modules/CMakeLists.txt
+++ a/llvm/cmake/modules/CMakeLists.txt
@@ -137,7 +137,6 @@ list(REMOVE_DUPLICATES LLVM_CONFIG_LIBRARY_DIRS)
 
 set(LLVM_CONFIG_BINARY_DIR "\${LLVM_INSTALL_PREFIX}")
 extend_path(LLVM_CONFIG_CMAKE_DIR "\${LLVM_INSTALL_PREFIX}" "${LLVM_INSTALL_PACKAGE_DIR}")
-extend_path(LLVM_CONFIG_TOOLS_BINARY_DIR "\${LLVM_INSTALL_PREFIX}" "${LLVM_TOOLS_INSTALL_DIR}")
 
 # Generate a default location for lit
 if (LLVM_INSTALL_UTILS AND LLVM_BUILD_UTILS)
diff --git b/openmp/CMakeLists.txt a/openmp/CMakeLists.txt
index b6ddbe90516d..4530281aff26 100644
--- b/openmp/CMakeLists.txt
+++ a/openmp/CMakeLists.txt
@@ -1,12 +1,7 @@
 cmake_minimum_required(VERSION 3.13.4)
 
-set(LLVM_COMMON_CMAKE_UTILS ${CMAKE_CURRENT_SOURCE_DIR}/../cmake)
-
-# Add path for custom modules
-list(INSERT CMAKE_MODULE_PATH 0
-  "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
-  "${LLVM_COMMON_CMAKE_UTILS}/Modules"
-  )
+# Add cmake directory to search for custom cmake functions.
+set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake ${CMAKE_MODULE_PATH})
 
 # llvm/runtimes/ will set OPENMP_STANDALONE_BUILD.
 if (OPENMP_STANDALONE_BUILD OR "${CMAKE_SOURCE_DIR}" STREQUAL "${CMAKE_CURRENT_SOURCE_DIR}")
diff --git b/openmp/runtime/src/CMakeLists.txt a/openmp/runtime/src/CMakeLists.txt
index 02f65aac0d40..4068a5862b4a 100644
--- b/openmp/runtime/src/CMakeLists.txt
+++ a/openmp/runtime/src/CMakeLists.txt
@@ -8,8 +8,6 @@
 #//===----------------------------------------------------------------------===//
 #
 
-include(ExtendPath)
-
 # Configure omp.h, kmp_config.h and omp-tools.h if necessary
 configure_file(${LIBOMP_INC_DIR}/omp.h.var omp.h @ONLY)
 configure_file(kmp_config.h.cmake kmp_config.h @ONLY)
@@ -349,8 +347,8 @@ endif()
 add_dependencies(libomp-micro-tests libomp-test-deps)
 
 # Install rules
-# We want to install libomp in ${DESTDIR}/${CMAKE_INSTALL_FULL_LIBDIR}
-# We want to install headers in ${DESTDIR}/${CMAKE_INSTALL_FULL_INCLUDEDIR}
+# We want to install libomp in DESTDIR/CMAKE_INSTALL_PREFIX/lib
+# We want to install headers in DESTDIR/CMAKE_INSTALL_PREFIX/include
 if(${OPENMP_STANDALONE_BUILD})
   set(LIBOMP_HEADERS_INSTALL_PATH "${CMAKE_INSTALL_INCLUDEDIR}")
 else()
@@ -364,10 +362,9 @@ if(WIN32)
   set(LIBOMP_ALIASES "libiomp5md")
   foreach(alias IN LISTS LIBOMP_ALIASES)
     install(CODE "execute_process(COMMAND \"\${CMAKE_COMMAND}\" -E copy \"${LIBOMP_LIB_FILE}\"
-      \"${alias}${LIBOMP_LIBRARY_SUFFIX}\" WORKING_DIRECTORY \"${CMAKE_INSTALL_FULL_BINDIR}\")")
-    extend_path(outdir "${CMAKE_INSTALL_PREFIX}" "${OPENMP_INSTALL_LIBDIR}")
+      \"${alias}${LIBOMP_LIBRARY_SUFFIX}\" WORKING_DIRECTORY \"\${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_BINDIR}\")")
     install(CODE "execute_process(COMMAND \"\${CMAKE_COMMAND}\" -E copy \"${LIBOMP_IMP_LIB_FILE}\"
-      \"${alias}${CMAKE_STATIC_LIBRARY_SUFFIX}\" WORKING_DIRECTORY \"${outdir}\")")
+      \"${alias}${CMAKE_STATIC_LIBRARY_SUFFIX}\" WORKING_DIRECTORY \"\${CMAKE_INSTALL_PREFIX}/${OPENMP_INSTALL_LIBDIR}\")")
   endforeach()
 else()
 
@@ -377,10 +374,9 @@ else()
     # Create aliases (symlinks) of the library for backwards compatibility
     set(LIBOMP_ALIASES "libgomp;libiomp5")
     foreach(alias IN LISTS LIBOMP_ALIASES)
-      extend_path(outdir "${CMAKE_INSTALL_PREFIX}" "${OPENMP_INSTALL_LIBDIR}")
       install(CODE "execute_process(COMMAND \"\${CMAKE_COMMAND}\" -E create_symlink \"${LIBOMP_LIB_FILE}\"
         \"${alias}${LIBOMP_LIBRARY_SUFFIX}\" WORKING_DIRECTORY
-        \"\$ENV{DESTDIR}\${outdir}\")")
+        \"\$ENV{DESTDIR}\${CMAKE_INSTALL_PREFIX}/${OPENMP_INSTALL_LIBDIR}\")")
     endforeach()
   endif()
 endif()