[openmp][cmake] Use `GNUInstallDirs` to support custom installation dirs

[Ericson2314]

Summary

I am breaking apart D99484 so the cause of build failures is easier to
understand.

[Ericson2314]

This part, too, checks out. Landing next.

[mstorsjo]

openmp/runtime/src/CMakeLists.txt

361

This change seems to have broken one aspect: When doing ninja install I now get a warning saying Error copying file "libomp.dll" to "libiomp5md.dll"., and libiomp5md.dll isn't installed.

I believe the reason is that the inline cmake snippet is written to runtime/src/cmake_install.cmake and then executed on install, but on install, ${CMAKE_INSTALL_BINDIR} isn't set (as GNUInstallDirs isn't included there). Should this maybe expand ${CMAKE_INSTALL_BINDIR} right here instead of deferring it to the install cmake, or what's the right course of action?

[Ericson2314]

openmp/runtime/src/CMakeLists.txt

361

Did in D118528!

openmp/CMakeLists.txt

 cmake_minimum_required(VERSION 3.13.4)
 
 # 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}")
   set(OPENMP_STANDALONE_BUILD TRUE)
   project(openmp C CXX)
+endif()
+
+# Must go below project(..)
+include(GNUInstallDirs)
 
+if (OPENMP_STANDALONE_BUILD)
   # CMAKE_BUILD_TYPE was not set, default to Release.
   if (NOT CMAKE_BUILD_TYPE)
     set(CMAKE_BUILD_TYPE Release)
   endif()
 
   # Group common settings.
   set(OPENMP_ENABLE_WERROR FALSE CACHE BOOL
     "Enable -Werror flags to turn warnings into errors for supporting compilers.")

openmp/libompd/src/CMakeLists.txt

include_directories (
         ${CMAKE_CURRENT_SOURCE_DIR}
         ${LIBOMP_INCLUDE_DIR}
         ${LIBOMP_SRC_DIR}
 )
 
 INSTALL( TARGETS ompd
         LIBRARY DESTINATION ${OPENMP_INSTALL_LIBDIR}
         ARCHIVE DESTINATION ${OPENMP_INSTALL_LIBDIR}
-        RUNTIME DESTINATION bin )
+        RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}" )

openmp/runtime/cmake/LibompCheckLinkerFlag.cmake

 #
 #//===----------------------------------------------------------------------===//
 #//
 #// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 #// See https://llvm.org/LICENSE.txt for license information.
 #// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 #//
 #//===----------------------------------------------------------------------===//
 #
 
+include(GNUInstallDirs)
+
 # Checking a linker flag to build a shared library
 # There is no real trivial way to do this in CMake, so we implement it here
 # this will have ${boolean} = TRUE if the flag succeeds, otherwise FALSE.
 function(libomp_check_linker_flag flag boolean)
   if(NOT DEFINED "${boolean}")
   set(retval TRUE)
   set(library_source
     "int foo(int a) { return a*a; }")

openmp/runtime/src/CMakeLists.txt

if(${MIC})
   add_dependencies(libomp-micro-tests libomp-test-instr)
 endif()
 add_dependencies(libomp-micro-tests libomp-test-deps)
 
 # Install rules
 # We want to install libomp in DESTDIR/CMAKE_INSTALL_PREFIX/lib
 # We want to install headers in DESTDIR/CMAKE_INSTALL_PREFIX/include
 if(${OPENMP_STANDALONE_BUILD})
-  set(LIBOMP_HEADERS_INSTALL_PATH include)
+  set(LIBOMP_HEADERS_INSTALL_PATH "${CMAKE_INSTALL_INCLUDEDIR}")
 else()
   string(REGEX MATCH "[0-9]+\\.[0-9]+(\\.[0-9]+)?" CLANG_VERSION ${PACKAGE_VERSION})
   set(LIBOMP_HEADERS_INSTALL_PATH "${OPENMP_INSTALL_LIBDIR}/clang/${CLANG_VERSION}/include")
 endif()
 if(WIN32)
-  install(TARGETS omp RUNTIME DESTINATION bin)
+  install(TARGETS omp RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
   install(TARGETS ${LIBOMP_IMP_LIB_TARGET} ARCHIVE DESTINATION "${OPENMP_INSTALL_LIBDIR}")
   # Create aliases (regular copies) of the library for backwards compatibility
   set(LIBOMP_ALIASES "libiomp5md")
   foreach(alias IN LISTS LIBOMP_ALIASES)
     install(CODE "execute_process(COMMAND \"\${CMAKE_COMMAND}\" -E copy \"${LIBOMP_LIB_FILE}\"
-      \"${alias}${LIBOMP_LIBRARY_SUFFIX}\" WORKING_DIRECTORY \"\${CMAKE_INSTALL_PREFIX}/bin\")")
+      \"${alias}${LIBOMP_LIBRARY_SUFFIX}\" WORKING_DIRECTORY \"\${CMAKE_INSTALL_BINDIR}\")")
     install(CODE "execute_process(COMMAND \"\${CMAKE_COMMAND}\" -E copy \"${LIBOMP_IMP_LIB_FILE}\"
       \"${alias}${CMAKE_STATIC_LIBRARY_SUFFIX}\" WORKING_DIRECTORY \"\${CMAKE_INSTALL_PREFIX}/${OPENMP_INSTALL_LIBDIR}\")")
   endforeach()
 else()
 
   install(TARGETS omp ${LIBOMP_INSTALL_KIND} DESTINATION "${OPENMP_INSTALL_LIBDIR}")
 
   if(${LIBOMP_INSTALL_ALIASES})

openmp/tools/multiplex/CMakeLists.txt

 if(LIBOMP_OMPT_SUPPORT)
   include_directories(${LIBOMP_INCLUDE_DIR})
 
   add_library(ompt-multiplex INTERFACE)
   target_include_directories(ompt-multiplex INTERFACE ${CMAKE_CURRENT_SOURCE_DIR})
 
-  install(FILES ompt-multiplex.h DESTINATION include)
+  install(FILES ompt-multiplex.h DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}")
 
   add_subdirectory(tests)
 endif()