Revert "[cmake] Use CMAKE_INSTALL_LIBDIR too"

This reverts commit f7a3309.

Unfortunately this causes a number of failures that didn't show up in my
local build.

bolt/runtime/CMakeLists.txt

@@ -1,6 +1,5 @@
 cmake_minimum_required(VERSION 3.13.4)
 include(CheckIncludeFiles)
-include(GNUInstallDirs)
 
 set(CMAKE_CXX_EXTENSIONS OFF)
 set(CMAKE_CXX_STANDARD 17)
@@ -33,8 +32,8 @@ target_include_directories(bolt_rt_instr PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
 target_compile_options(bolt_rt_hugify PRIVATE ${BOLT_RT_FLAGS})
 target_include_directories(bolt_rt_hugify PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
 
-install(TARGETS bolt_rt_instr DESTINATION "${CMAKE_INSTALL_LIBDIR}")
-install(TARGETS bolt_rt_hugify DESTINATION "${CMAKE_INSTALL_LIBDIR}")
+install(TARGETS bolt_rt_instr DESTINATION lib)
+install(TARGETS bolt_rt_hugify DESTINATION lib)
 
 if (CMAKE_CXX_COMPILER_ID MATCHES ".*Clang.*")
   add_library(bolt_rt_instr_osx STATIC
@@ -45,5 +44,5 @@ if (CMAKE_CXX_COMPILER_ID MATCHES ".*Clang.*")
   target_compile_options(bolt_rt_instr_osx PRIVATE
     -target x86_64-apple-darwin19.6.0
     ${BOLT_RT_FLAGS})
-  install(TARGETS bolt_rt_instr_osx DESTINATION "${CMAKE_INSTALL_LIBDIR}")
+  install(TARGETS bolt_rt_instr_osx DESTINATION lib)
 endif()

clang/CMakeLists.txt

@@ -37,7 +37,7 @@ if(CLANG_BUILT_STANDALONE)
 
   # They are used as destination of target generators.
   set(LLVM_RUNTIME_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin)
-  set(LLVM_LIBRARY_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib)
+  set(LLVM_LIBRARY_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib${LLVM_LIBDIR_SUFFIX})
   if(WIN32 OR CYGWIN)
     # DLL platform -- put DLLs into bin.
     set(LLVM_SHLIB_OUTPUT_INTDIR ${LLVM_RUNTIME_OUTPUT_INTDIR})
@@ -72,8 +72,8 @@ if(CLANG_BUILT_STANDALONE)
   link_directories("${LLVM_LIBRARY_DIR}")
 
   set( CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin )
-  set( CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib )
-  set( CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib )
+  set( CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX} )
+  set( CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX} )
 
   if(LLVM_INCLUDE_TESTS)
     find_package(Python3 ${LLVM_MINIMUM_PYTHON_VERSION} REQUIRED
@@ -303,6 +303,9 @@ if (NOT LLVM_LINK_LLVM_DYLIB AND CLANG_LINK_CLANG_DYLIB)
                       "LLVM_LINK_LLVM_DYLIB=OFF")
 endif()
 
+# The libdir suffix must exactly match whatever LLVM's configuration used.
+set(CLANG_LIBDIR_SUFFIX "${LLVM_LIBDIR_SUFFIX}")
+
 set(CLANG_TOOLS_INSTALL_DIR "${CMAKE_INSTALL_BINDIR}" CACHE PATH
     "Path for binary subdirectory (defaults to '${CMAKE_INSTALL_BINDIR}')")
 mark_as_advanced(CLANG_TOOLS_INSTALL_DIR)
@@ -868,8 +871,6 @@ if(CLANG_BUILT_STANDALONE)
   process_llvm_pass_plugins()
 endif()
 
-get_filename_component(CLANG_INSTALL_LIBDIR_BASENAME "${CMAKE_INSTALL_LIBDIR}" NAME)
-
 configure_file(
   ${CLANG_SOURCE_DIR}/include/clang/Config/config.h.cmake
   ${CLANG_BINARY_DIR}/include/clang/Config/config.h)

clang/cmake/caches/Android-stage2.cmake

@@ -4,7 +4,7 @@ set(CLANG_VENDOR Android CACHE STRING "")
 set(CMAKE_BUILD_TYPE Release CACHE STRING "")
 set(LLVM_ENABLE_THREADS OFF CACHE BOOL "")
 set(LLVM_ENABLE_ASSERTIONS ON CACHE BOOL "")
-set(CMAKE_INSTALL_LIBDIR "lib64" CACHE STRING "")
+set(LLVM_LIBDIR_SUFFIX 64 CACHE STRING "")
 set(LLVM_ENABLE_LIBCXX ON CACHE BOOL "")
 
 set(ANDROID_RUNTIMES_ENABLE_ASSERTIONS ON CACHE BOOL "")

clang/cmake/caches/Android.cmake

@@ -13,7 +13,7 @@ set(HAVE_LIBCXXABI ON CACHE BOOL "")
 set(LLVM_BUILD_TOOLS OFF CACHE BOOL "")
 set(LLVM_ENABLE_ASSERTIONS ON CACHE BOOL "")
 set(LLVM_ENABLE_THREADS OFF CACHE BOOL "")
-set(CMAKE_INSTALL_LIBDIR "lib64" CACHE STRING "")
+set(LLVM_LIBDIR_SUFFIX 64 CACHE STRING "")
 set(LLVM_TOOL_CLANG_TOOLS_EXTRA_BUILD OFF CACHE BOOL "")
 set(LLVM_TOOL_OPENMP_BUILD OFF CACHE BOOL "")
 set(LLVM_ENABLE_LIBCXX ON CACHE BOOL "")

clang/cmake/modules/AddClang.cmake

@@ -119,8 +119,8 @@ macro(add_clang_library name)
         install(TARGETS ${lib}
           COMPONENT ${lib}
           ${export_to_clangtargets}
-          LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
-          ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+          LIBRARY DESTINATION lib${LLVM_LIBDIR_SUFFIX}
+          ARCHIVE DESTINATION lib${LLVM_LIBDIR_SUFFIX}
           RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
 
         if (NOT LLVM_ENABLE_IDE)

clang/cmake/modules/CMakeLists.txt

@@ -9,13 +9,13 @@ include(FindPrefixFromConfig)
 set(CLANG_INSTALL_PACKAGE_DIR "${CMAKE_INSTALL_PACKAGEDIR}/clang" CACHE STRING
   "Path for CMake subdirectory for Clang (defaults to '${CMAKE_INSTALL_PACKAGEDIR}/clang')")
 # CMAKE_INSTALL_PACKAGEDIR might be absolute, so don't reuse below.
-set(clang_cmake_builddir "${CMAKE_BINARY_DIR}/lib/cmake/clang")
+set(clang_cmake_builddir "${CMAKE_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX}/cmake/clang")
 
 # Keep this in sync with llvm/cmake/CMakeLists.txt!
 set(LLVM_INSTALL_PACKAGE_DIR "${CMAKE_INSTALL_PACKAGEDIR}/llvm" CACHE STRING
   "Path for CMake subdirectory for LLVM (defaults to '${CMAKE_INSTALL_PACKAGEDIR}/llvm')")
 # CMAKE_INSTALL_PACKAGEDIR might be absolute, so don't reuse below.
-set(llvm_cmake_builddir "${LLVM_BINARY_DIR}/lib/cmake/llvm")
+set(llvm_cmake_builddir "${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX}/cmake/llvm")
 
 get_property(CLANG_EXPORTS GLOBAL PROPERTY CLANG_EXPORTS)
 export(TARGETS ${CLANG_EXPORTS} FILE ${clang_cmake_builddir}/ClangTargets.cmake)

clang/include/clang/Config/config.h.cmake

@@ -53,8 +53,8 @@
 /* Default architecture for SystemZ. */
 #define CLANG_SYSTEMZ_DEFAULT_ARCH "${CLANG_SYSTEMZ_DEFAULT_ARCH}"
 
-/* Multilib basename for libdir. */
-#define CLANG_INSTALL_LIBDIR_BASENAME "${CLANG_INSTALL_LIBDIR_BASENAME}"
+/* Multilib suffix for libdir. */
+#define CLANG_LIBDIR_SUFFIX "${CLANG_LIBDIR_SUFFIX}"
 
 /* Relative directory for resource files */
 #define CLANG_RESOURCE_DIR "${CLANG_RESOURCE_DIR}"

clang/lib/Driver/Driver.cpp

@@ -180,7 +180,7 @@ std::string Driver::GetResourcesPath(StringRef BinaryPath,
     // path of the embedding binary, which for LLVM binaries will be in bin/.
     // ../lib gets us to lib/ in both cases.
     P = llvm::sys::path::parent_path(Dir);
-    llvm::sys::path::append(P, CLANG_INSTALL_LIBDIR_BASENAME, "clang",
+    llvm::sys::path::append(P, Twine("lib") + CLANG_LIBDIR_SUFFIX, "clang",
                             CLANG_VERSION_STRING);
   }
 

clang/lib/Driver/ToolChains/CommonArgs.cpp

@@ -502,8 +502,7 @@ void tools::addLTOOptions(const ToolChain &ToolChain, const ArgList &Args,
 
     SmallString<1024> Plugin;
     llvm::sys::path::native(
-        Twine(D.Dir) + "/../" CLANG_INSTALL_LIBDIR_BASENAME "/LLVMgold" +
-            Suffix,
+        Twine(D.Dir) + "/../lib" CLANG_LIBDIR_SUFFIX "/LLVMgold" + Suffix,
         Plugin);
     CmdArgs.push_back(Args.MakeArgString(Plugin));
   }
@@ -659,7 +658,7 @@ void tools::addOpenMPRuntimeSpecificRPath(const ToolChain &TC,
     // runtime
     SmallString<256> DefaultLibPath =
         llvm::sys::path::parent_path(TC.getDriver().Dir);
-    llvm::sys::path::append(DefaultLibPath, CLANG_INSTALL_LIBDIR_BASENAME);
+    llvm::sys::path::append(DefaultLibPath, Twine("lib") + CLANG_LIBDIR_SUFFIX);
     CmdArgs.push_back("-rpath");
     CmdArgs.push_back(Args.MakeArgString(DefaultLibPath));
   }
@@ -672,7 +671,7 @@ void tools::addOpenMPRuntimeLibraryPath(const ToolChain &TC,
   // runtime.
   SmallString<256> DefaultLibPath =
       llvm::sys::path::parent_path(TC.getDriver().Dir);
-  llvm::sys::path::append(DefaultLibPath, CLANG_INSTALL_LIBDIR_BASENAME);
+  llvm::sys::path::append(DefaultLibPath, Twine("lib") + CLANG_LIBDIR_SUFFIX);
   CmdArgs.push_back(Args.MakeArgString("-L" + DefaultLibPath));
 }
 
@@ -1948,7 +1947,7 @@ void tools::AddStaticDeviceLibs(Compilation *C, const Tool *T,
 
   // Add path to lib-debug folders
   SmallString<256> DefaultLibPath = llvm::sys::path::parent_path(D.Dir);
-  llvm::sys::path::append(DefaultLibPath, CLANG_INSTALL_LIBDIR_BASENAME);
+  llvm::sys::path::append(DefaultLibPath, Twine("lib") + CLANG_LIBDIR_SUFFIX);
   LibraryPaths.emplace_back(DefaultLibPath.c_str());
 
   // Build list of Static Device Libraries SDLs specified by -l option
@@ -2077,7 +2076,7 @@ void tools::addOpenMPDeviceRTL(const Driver &D,
 
   // Add path to clang lib / lib64 folder.
   SmallString<256> DefaultLibPath = llvm::sys::path::parent_path(D.Dir);
-  llvm::sys::path::append(DefaultLibPath, CLANG_INSTALL_LIBDIR_BASENAME);
+  llvm::sys::path::append(DefaultLibPath, Twine("lib") + CLANG_LIBDIR_SUFFIX);
   LibraryPaths.emplace_back(DefaultLibPath.c_str());
 
   // Add user defined library paths from LIBRARY_PATH.

clang/lib/Driver/ToolChains/Cuda.cpp

@@ -592,7 +592,7 @@ void NVPTX::OpenMPLinker::ConstructJob(Compilation &C, const JobAction &JA,
   // Add paths for the default clang library path.
   SmallString<256> DefaultLibPath =
       llvm::sys::path::parent_path(TC.getDriver().Dir);
-  llvm::sys::path::append(DefaultLibPath, CLANG_INSTALL_LIBDIR_BASENAME);
+  llvm::sys::path::append(DefaultLibPath, "lib" CLANG_LIBDIR_SUFFIX);
   CmdArgs.push_back(Args.MakeArgString(Twine("-L") + DefaultLibPath));
 
   for (const auto &II : Inputs) {

clang/lib/Headers/CMakeLists.txt

@@ -420,7 +420,7 @@ 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 ${CMAKE_INSTALL_LIBDIR}/clang/${CLANG_VERSION}/include)
+set(header_install_dir lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION}/include)
 
 #############################################################
 # Install rules for the catch-all clang-resource-headers target

clang/runtime/CMakeLists.txt

@@ -84,12 +84,10 @@ if(LLVM_BUILD_EXTERNAL_COMPILER_RT AND EXISTS ${COMPILER_RT_SRC_ROOT}/)
                -DLLVM_LIT_ARGS=${LLVM_LIT_ARGS}
                -DCOMPILER_RT_OUTPUT_DIR=${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION}
                -DCOMPILER_RT_EXEC_OUTPUT_DIR=${LLVM_RUNTIME_OUTPUT_INTDIR}
-               -DCOMPILER_RT_INSTALL_PATH:PATH=lib/clang/${CLANG_VERSION}
+               -DCOMPILER_RT_INSTALL_PATH:PATH=lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION}
                -DCOMPILER_RT_INCLUDE_TESTS=${LLVM_INCLUDE_TESTS}
-               -DCMAKE_INSTALL_PREFIX="${CMAKE_INSTALL_PREFIX}"
-               -DCMAKE_INSTALL_BINDIR="${CMAKE_INSTALL_BINDIR}"
-               -DCMAKE_INSTALL_LIBDIR="${CMAKE_INSTALL_LIBDIR}"
-               -DCMAKE_INSTALL_INCLUDEDIR="${CMAKE_INSTALL_INCLUDEDIR}"
+               -DCMAKE_INSTALL_PREFIX=${CMAKE_INSTALL_PREFIX}
+               -DLLVM_LIBDIR_SUFFIX=${LLVM_LIBDIR_SUFFIX}
                -DLLVM_RUNTIME_OUTPUT_INTDIR=${LLVM_RUNTIME_OUTPUT_INTDIR}
                -DCMAKE_OSX_DEPLOYMENT_TARGET=${CMAKE_OSX_DEPLOYMENT_TARGET}
                -DCMAKE_OSX_SYSROOT:PATH=${CMAKE_OSX_SYSROOT}

clang/tools/libclang/CMakeLists.txt

@@ -180,7 +180,7 @@ foreach(PythonVersion ${CLANG_PYTHON_BINDINGS_VERSIONS})
           COMPONENT
             libclang-python-bindings
           DESTINATION
-            "${CMAKE_INSTALL_LIBDIR}/python${PythonVersion}/site-packages")
+            "lib${LLVM_LIBDIR_SUFFIX}/python${PythonVersion}/site-packages")
 endforeach()
 if(NOT LLVM_ENABLE_IDE)
   add_custom_target(libclang-python-bindings)

clang/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(PROGRAMS lib/libscanbuild/${lib}
-          DESTINATION "${CMAKE_INSTALL_LIBDIR}/libscanbuild"
+          DESTINATION lib/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(PROGRAMS lib/libscanbuild/resources/${resource}
-          DESTINATION "${CMAKE_INSTALL_LIBDIR}/libscanbuild/resources"
+          DESTINATION lib/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(PROGRAMS lib/libear/${lib}
-          DESTINATION "${CMAKE_INSTALL_LIBDIR}/libear"
+          DESTINATION lib/libear
           COMPONENT scan-build-py)
 endforeach()
 

cmake/Modules/GNUInstallPackageDir.cmake

@@ -29,5 +29,5 @@ macro(_GNUInstallPackageDir_cache_path var default description)
   _GNUInstallPackageDir_cache_convert_to_path("${var}" "${description}")
 endmacro()
 
-_GNUInstallPackageDir_cache_path(CMAKE_INSTALL_PACKAGEDIR "${CMAKE_INSTALL_LIBDIR}/cmake"
+_GNUInstallPackageDir_cache_path(CMAKE_INSTALL_PACKAGEDIR "lib${LLVM_LIBDIR_SUFFIX}/cmake"
   "Directories containing installed CMake modules (lib/cmake)")

compiler-rt/cmake/Modules/CompilerRTAIXUtils.cmake

@@ -62,7 +62,7 @@ macro(archive_aix_libatomic name libname)
     # setting _install_rpath on AIX for reference.
     if(LLVM_LIBRARY_OUTPUT_INTDIR AND CMAKE_INSTALL_PREFIX)
       set(output_dir "${LLVM_LIBRARY_OUTPUT_INTDIR}")
-      set(install_dir "${CMAKE_INSTALL_LIBDIR}")
+      set(install_dir "${CMAKE_INSTALL_PREFIX}/lib${LLVM_LIBDIR_SUFFIX}")
     else()
       get_compiler_rt_output_dir(${COMPILER_RT_DEFAULT_TARGET_ARCH} output_dir)
       get_compiler_rt_install_dir(${COMPILER_RT_DEFAULT_TARGET_ARCH} install_dir)

compiler-rt/cmake/Modules/CompilerRTUtils.cmake

@@ -377,7 +377,7 @@ macro(load_llvm_config)
       file(TO_CMAKE_PATH ${LLVM_CMAKE_DIR_FROM_LLVM_CONFIG} LLVM_CMAKE_DIR)
     else()
       file(TO_CMAKE_PATH ${LLVM_BINARY_DIR} LLVM_BINARY_DIR_CMAKE_STYLE)
-      set(LLVM_CMAKE_DIR "${LLVM_BINARY_DIR_CMAKE_STYLE}/lib/cmake/llvm")
+      set(LLVM_CMAKE_DIR "${LLVM_BINARY_DIR_CMAKE_STYLE}/lib${LLVM_LIBDIR_SUFFIX}/cmake/llvm")
     endif()
 
     set(LLVM_CMAKE_INCLUDE_FILE "${LLVM_CMAKE_DIR}/LLVMConfig.cmake")
@@ -393,7 +393,7 @@ macro(load_llvm_config)
     unset(LLVM_CMAKE_INCLUDE_FILE)
 
     set(LLVM_LIBRARY_OUTPUT_INTDIR
-      ${LLVM_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib)
+      ${LLVM_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib${LLVM_LIBDIR_SUFFIX})
   endif()
 
   # Finally set the cache variable now that `llvm-config` has also had a chance

compiler-rt/cmake/base-config-ix.cmake

@@ -45,7 +45,7 @@ if (LLVM_TREE_AVAILABLE)
   # Setup the paths where compiler-rt runtimes and headers should be stored.
   set(COMPILER_RT_OUTPUT_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION})
   set(COMPILER_RT_EXEC_OUTPUT_DIR ${LLVM_RUNTIME_OUTPUT_INTDIR})
-  set(COMPILER_RT_INSTALL_PATH "${CMAKE_INSTALL_LIBDIR}/clang/${CLANG_VERSION}")
+  set(COMPILER_RT_INSTALL_PATH lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION})
   option(COMPILER_RT_INCLUDE_TESTS "Generate and build compiler-rt unit tests."
          ${LLVM_INCLUDE_TESTS})
   option(COMPILER_RT_ENABLE_WERROR "Fail and stop if warning is triggered"
@@ -97,30 +97,25 @@ if(NOT DEFINED COMPILER_RT_OS_DIR)
     string(TOLOWER ${CMAKE_SYSTEM_NAME} COMPILER_RT_OS_DIR)
   endif()
 endif()
-
 if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
   set(COMPILER_RT_OUTPUT_LIBRARY_DIR
     ${COMPILER_RT_OUTPUT_DIR}/lib)
-  # Don't use "${CMAKE_INSTALL_LIBDIR}", because the intended use-case is that
-  # "${COMPILER_RT_INSTALL_PATH}" is already non-trival and probably includes
-  # "${CMAKE_INSTALL_LIBDIR}".
-  extend_path(default_install_path "${COMPILER_RT_INSTALL_PATH}" "lib")
-else()
+  extend_path(default_install_path "${COMPILER_RT_INSTALL_PATH}" lib)
+  set(COMPILER_RT_INSTALL_LIBRARY_DIR "${default_install_path}" CACHE PATH
+    "Path where built compiler-rt libraries should be installed.")
+else(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
   set(COMPILER_RT_OUTPUT_LIBRARY_DIR
     ${COMPILER_RT_OUTPUT_DIR}/lib/${COMPILER_RT_OS_DIR})
-  extend_path(default_install_path "${COMPILER_RT_INSTALL_PATH}" "${CMAKE_INSTALL_LIBDIR}/${COMPILER_RT_OS_DIR}")
+  extend_path(default_install_path "${COMPILER_RT_INSTALL_PATH}" "lib/${COMPILER_RT_OS_DIR}")
+  set(COMPILER_RT_INSTALL_LIBRARY_DIR "${default_install_path}" CACHE PATH
+    "Path where built compiler-rt libraries should be installed.")
 endif()
-set(COMPILER_RT_INSTALL_LIBRARY_DIR "${default_install_path}" CACHE PATH
-  "Path where built compiler-rt libraries should be installed.")
-
 extend_path(default_install_path "${COMPILER_RT_INSTALL_PATH}" "${CMAKE_INSTALL_BINDIR}")
 set(COMPILER_RT_INSTALL_BINARY_DIR "${default_install_path}" CACHE PATH
   "Path where built compiler-rt executables should be installed.")
-
 extend_path(default_install_path "${COMPILER_RT_INSTALL_PATH}" "${CMAKE_INSTALL_INCLUDEDIR}")
 set(COMPILER_RT_INSTALL_INCLUDE_DIR "${default_install_path}" CACHE PATH
   "Path where compiler-rt headers should be installed.")
-
 extend_path(default_install_path "${COMPILER_RT_INSTALL_PATH}" "${CMAKE_INSTALL_DATADIR}")
 set(COMPILER_RT_INSTALL_DATA_DIR "${default_install_path}" CACHE PATH
   "Path where compiler-rt data files should be installed.")

compiler-rt/docs/BuildingCompilerRT.rst

@@ -79,3 +79,14 @@ Compiler-RT specific options
 
   Path where Compiler-RT data should be installed. If a relative
   path, relative to ``COMPILER_RT_INSTALL_PATH``.
+
+.. _LLVM-specific variables:
+
+LLVM-specific options
+---------------------
+
+.. option:: LLVM_LIBDIR_SUFFIX:STRING
+
+  Extra suffix to append to the directory where libraries are to be
+  installed. On a 64-bit architecture, one could use ``-DLLVM_LIBDIR_SUFFIX=64``
+  to install libraries to ``/usr/lib64``.

flang/CMakeLists.txt

@@ -129,9 +129,9 @@ if (FLANG_STANDALONE_BUILD)
 
   set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
   set(CMAKE_LIBRARY_OUTPUT_DIRECTORY
-    ${CMAKE_BINARY_DIR}/lib)
+    ${CMAKE_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX})
   set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY
-    ${CMAKE_BINARY_DIR}/lib)
+    ${CMAKE_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX})
 
   set(BACKEND_PACKAGE_STRING "LLVM ${LLVM_PACKAGE_VERSION}")
   set(LLVM_EXTERNAL_LIT "${LLVM_TOOLS_BINARY_DIR}/llvm-lit" CACHE STRING "Command used to spawn lit")

flang/cmake/modules/AddFlang.cmake

@@ -71,8 +71,8 @@ macro(add_flang_library name)
       install(TARGETS ${name}
         COMPONENT ${name}
         ${export_to_flangtargets}
-        LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
-        ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+        LIBRARY DESTINATION lib${LLVM_LIBDIR_SUFFIX}
+        ARCHIVE DESTINATION lib${LLVM_LIBDIR_SUFFIX}
         RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
 
       if (NOT LLVM_ENABLE_IDE)

flang/cmake/modules/CMakeLists.txt

@@ -8,13 +8,13 @@ include(FindPrefixFromConfig)
 set(FLANG_INSTALL_PACKAGE_DIR "${CMAKE_INSTALL_PACKAGEDIR}/flang" CACHE STRING
   "Path for CMake subdirectory for Flang (defaults to '${CMAKE_INSTALL_PACKAGEDIR}/flang')")
 # CMAKE_INSTALL_PACKAGEDIR might be absolute, so don't reuse below.
-set(flang_cmake_builddir "${CMAKE_BINARY_DIR}/lib/cmake/flang")
+set(flang_cmake_builddir "${CMAKE_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX}/cmake/flang")
 
 # Keep this in sync with llvm/cmake/CMakeLists.txt!
 set(LLVM_INSTALL_PACKAGE_DIR "${CMAKE_INSTALL_PACKAGEDIR}/llvm" CACHE STRING
   "Path for CMake subdirectory for LLVM (defaults to '${CMAKE_INSTALL_PACKAGEDIR}/llvm')")
 # CMAKE_INSTALL_PACKAGEDIR might be absolute, so don't reuse below.
-set(llvm_cmake_builddir "${LLVM_BINARY_DIR}/lib/cmake/llvm")
+set(llvm_cmake_builddir "${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX}/cmake/llvm")
 
 get_property(FLANG_EXPORTS GLOBAL PROPERTY FLANG_EXPORTS)
 export(TARGETS ${FLANG_EXPORTS} FILE ${flang_cmake_builddir}/FlangTargets.cmake)

libc/CMakeLists.txt

@@ -1,7 +1,5 @@
 cmake_minimum_required(VERSION 3.13.4)
 
-include(GNUInstallDirs)
-
 # Default to C++17
 set(CMAKE_CXX_STANDARD 17)
 

libc/lib/CMakeLists.txt

@@ -5,9 +5,9 @@ add_entrypoint_library(
 )
 
 if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR)
-  set(LIBC_INSTALL_LIBRARY_DIR ${CMAKE_INSTALL_LIBDIR}/${LLVM_DEFAULT_TARGET_TRIPLE})
+  set(LIBC_INSTALL_LIBRARY_DIR lib${LLVM_LIBDIR_SUFFIX}/${LLVM_DEFAULT_TARGET_TRIPLE})
 else()
-  set(LIBC_INSTALL_LIBRARY_DIR ${CMAKE_INSTALL_LIBDIR})
+  set(LIBC_INSTALL_LIBRARY_DIR lib${LLVM_LIBDIR_SUFFIX})
 endif()
 
 install(