[OpenMP] Fixed include directories for OpenMP when building OpenMP with LLVM_ENABLE_RUNTIMES

[tianshilei1992]

Summary

Some LLVM headers are generated by CMake. Before the installation,
LLVM's headers are distributed everywhere, some of which are in
${LLVM_SRC_ROOT}/llvm/include/llvm, and some are in
${LLVM_BINARY_ROOT}/include/llvm. After intallation, they're all in
${LLVM_INSTALLATION_ROOT}/include/llvm.

OpenMP now depends on LLVM headers. Some headers depend on headers generated
by CMake. When building OpenMP along with LLVM, a.k.a via LLVM_ENABLE_RUNTIMES,
we need to tell OpenMP where it can find those headers, especially those still
have not been copied/installed.

[jdoerfert]

LGTM

[jhuber6]

I tested it with a clean build using GCC 8.3 and CUDA 10.1, the resulting compiler successfuly built an offloading application that ran on the CUDA device. LGTM.

openmp/CMakeLists.txt

else()
 
   if (NOT MSVC)
     set(OPENMP_TEST_C_COMPILER ${LLVM_RUNTIME_OUTPUT_INTDIR}/clang)
     set(OPENMP_TEST_CXX_COMPILER ${LLVM_RUNTIME_OUTPUT_INTDIR}/clang++)
   else()
     set(OPENMP_TEST_C_COMPILER ${LLVM_RUNTIME_OUTPUT_INTDIR}/clang.exe)
     set(OPENMP_TEST_CXX_COMPILER ${LLVM_RUNTIME_OUTPUT_INTDIR}/clang++.exe)
   endif()
+
+  list(APPEND LIBOMPTARGET_LLVM_INCLUDE_DIRS ${LLVM_MAIN_INCLUDE_DIR} ${LLVM_BINARY_DIR}/include)
 endif()
 
 # Check and set up common compiler flags.
 include(config-ix)
 include(HandleOpenMPOptions)
 
 # Set up testing infrastructure.
 include(OpenMPTesting)

 # Currently libomptarget cannot be compiled on Windows or MacOS X.
 # Since the device plugins are only supported on Linux anyway,
 # there is no point in trying to compile libomptarget on other OSes.
 if (APPLE OR WIN32 OR NOT OPENMP_HAVE_STD_CPP14_FLAG)
   set(ENABLE_LIBOMPTARGET OFF)
 endif()
 
 # Attempt to locate LLVM source, required by libomptarget
-if (NOT LIBOMPTARGET_LLVM_MAIN_INCLUDE_DIR)
+if (NOT LIBOMPTARGET_LLVM_INCLUDE_DIRS)
   if (LLVM_MAIN_INCLUDE_DIR)
-    set(LIBOMPTARGET_LLVM_MAIN_INCLUDE_DIR ${LLVM_MAIN_INCLUDE_DIR})
+    list(APPEND LIBOMPTARGET_LLVM_INCLUDE_DIRS ${LLVM_MAIN_INCLUDE_DIR})
   elseif (EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/../llvm/include)
-    set(LIBOMPTARGET_LLVM_MAIN_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/../llvm/include)
+    list(APPENDset LIBOMPTARGET_LLVM_INCLUDE_DIRS ${CMAKE_CURRENT_SOURCE_DIR}/../llvm/include)
   endif()
 endif()
 
-if (NOT LIBOMPTARGET_LLVM_MAIN_INCLUDE_DIR)
-  message(STATUS "Missing definition for LIBOMPTARGET_LLVM_MAIN_INCLUDE_DIR, disabling libomptarget")
+if (NOT LIBOMPTARGET_LLVM_INCLUDE_DIRS)
+  message(STATUS "Missing definition for LIBOMPTARGET_LLVM_INCLUDE_DIRS, disabling libomptarget")
   set(ENABLE_LIBOMPTARGET OFF)
 endif()
 
 option(OPENMP_ENABLE_LIBOMPTARGET "Enable building libomptarget for offloading."
        ${ENABLE_LIBOMPTARGET})
 option(OPENMP_ENABLE_LIBOMPTARGET_PROFILING "Enable time profiling for libomptarget."
        ${ENABLE_LIBOMPTARGET})
 if (OPENMP_ENABLE_LIBOMPTARGET)

openmp/libomptarget/CMakeLists.txt

 
 # Message utilities.
 include(LibomptargetUtils)
 
 # Get dependencies for the different components of the project.
 include(LibomptargetGetDependencies)
 
 # LLVM source tree is required at build time for libomptarget
-if (NOT LIBOMPTARGET_LLVM_MAIN_INCLUDE_DIR)
-  message(FATAL_ERROR "Missing definition for LIBOMPTARGET_LLVM_MAIN_INCLUDE_DIR")
+if (NOT LIBOMPTARGET_LLVM_INCLUDE_DIRS)
+  message(FATAL_ERROR "Missing definition for LIBOMPTARGET_LLVM_INCLUDE_DIRS")
 endif()
 
 # This is a list of all the targets that are supported/tested right now.
 set (LIBOMPTARGET_ALL_TARGETS "${LIBOMPTARGET_ALL_TARGETS} aarch64-unknown-linux-gnu")
 set (LIBOMPTARGET_ALL_TARGETS "${LIBOMPTARGET_ALL_TARGETS} powerpc64le-ibm-linux-gnu")
 set (LIBOMPTARGET_ALL_TARGETS "${LIBOMPTARGET_ALL_TARGETS} powerpc64-ibm-linux-gnu")
 set (LIBOMPTARGET_ALL_TARGETS "${LIBOMPTARGET_ALL_TARGETS} x86_64-pc-linux-gnu")
 set (LIBOMPTARGET_ALL_TARGETS "${LIBOMPTARGET_ALL_TARGETS} nvptx64-nvidia-cuda")

openmp/libomptarget/plugins/amdgpu/CMakeLists.txt

if(NOT LIBOMPTARGET_DEP_LIBELF_FOUND)
   return()
 endif()
 
 if(NOT CMAKE_SYSTEM_PROCESSOR MATCHES "(x86_64)|(ppc64le)|(aarch64)$" AND CMAKE_SYSTEM_NAME MATCHES "Linux")
   libomptarget_say("Not building AMDGPU plugin: only support AMDGPU in Linux x86_64, ppc64le, or aarch64 hosts.")
   return()
 endif()
 
-if (NOT LIBOMPTARGET_LLVM_MAIN_INCLUDE_DIR)
-  libomptarget_say("Not building AMDGPU plugin: Missing definition for LIBOMPTARGET_LLVM_MAIN_INCLUDE_DIR")
+if (NOT LIBOMPTARGET_LLVM_INCLUDE_DIRS)
+  libomptarget_say("Not building AMDGPU plugin: Missing definition for LIBOMPTARGET_LLVM_INCLUDE_DIRS")
   return()
 endif()
 
 libomptarget_say("Building amdgpu offloading plugin")
 
 ################################################################################
 # Define the suffix for the runtime messaging dumps.
 add_definitions(-DTARGET_NAME=AMDGPU)
 if(CMAKE_SYSTEM_PROCESSOR MATCHES "(ppc64le)|(aarch64)$")
    add_definitions(-DLITTLEENDIAN_CPU=1)
 endif()
 
 if(CMAKE_BUILD_TYPE MATCHES Debug)
   add_definitions(-DDEBUG)
 endif()
 
 include_directories(
   ${CMAKE_CURRENT_SOURCE_DIR}/impl
-  ${LIBOMPTARGET_LLVM_MAIN_INCLUDE_DIR}
+  ${LIBOMPTARGET_LLVM_INCLUDE_DIRS}
 )
 
 add_library(omptarget.rtl.amdgpu SHARED
       impl/atmi.cpp
       impl/atmi_interop_hsa.cpp
       impl/data.cpp
       impl/get_elf_mach_gfx_name.cpp
       impl/machine.cpp

openmp/libomptarget/src/CMakeLists.txt

 set(LIBOMPTARGET_SRC_FILES
   ${CMAKE_CURRENT_SOURCE_DIR}/api.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/device.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/interface.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/rtl.cpp
   ${CMAKE_CURRENT_SOURCE_DIR}/omptarget.cpp
 )
 
-include_directories(${LIBOMPTARGET_LLVM_MAIN_INCLUDE_DIR})
+include_directories(${LIBOMPTARGET_LLVM_INCLUDE_DIRS})
 
 # Build libomptarget library with libdl dependency. Add LLVMSupport
 # dependency if building in-tree with profiling enabled.
 if(OPENMP_STANDALONE_BUILD OR (NOT OPENMP_ENABLE_LIBOMPTARGET_PROFILING))
   add_library(omptarget SHARED ${LIBOMPTARGET_SRC_FILES})
   target_link_libraries(omptarget
     ${CMAKE_DL_LIBS}
     "-Wl,--version-script=${CMAKE_CURRENT_SOURCE_DIR}/exports")