[OpenMP] Fix building using LLVM_ENABLE_RUNTIMES

[ggeorgakoudis]

Summary

Fix when time profiling is enabled.

Related to: D94855

[JonChesterfield]

LGTM, thanks. Building via LLVM_ENABLE_RUNTIMES is what we're encouraging for GPU offloading.

[JonChesterfield]

This should probably be applied to the 12.0 release branch as well

[ggeorgakoudis]

In D95398#2525170, @JonChesterfield wrote:

This should probably be applied to the 12.0 release branch as well

@JonChesterfield I landed, is there anything else I should do?

[jdoerfert]

In D95398#2525516, @ggeorgakoudis wrote:

In D95398#2525170, @JonChesterfield wrote:

This should probably be applied to the 12.0 release branch as well

@JonChesterfield I landed, is there anything else I should do?

https://reviews.llvm.org/D95545#2525853

openmp/CMakeLists.txt

 # Set up testing infrastructure.
 include(OpenMPTesting)
 
 set(OPENMP_TEST_FLAGS "" CACHE STRING
   "Extra compiler flags to send to the test compiler.")
 set(OPENMP_TEST_OPENMP_FLAGS ${OPENMP_TEST_COMPILER_OPENMP_FLAGS} CACHE STRING
   "OpenMP compiler flag to use for testing OpenMP runtime libraries.")
 
-
-# Build host runtime library.
-add_subdirectory(runtime)
-
-
 set(ENABLE_LIBOMPTARGET ON)
 # 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()
 
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})
+
+# Build host runtime library, after LIBOMPTARGET variables are set since they are needed
+# to enable time profiling support in the OpenMP runtime.
+add_subdirectory(runtime)
+
 if (OPENMP_ENABLE_LIBOMPTARGET)
   # Check that the library can actually be built.
   if (APPLE OR WIN32)
     message(FATAL_ERROR "libomptarget cannot be built on Windows and MacOS X!")
   elseif (NOT OPENMP_HAVE_STD_CPP14_FLAG)
     message(FATAL_ERROR "Host compiler must support C++14 to build libomptarget!")
   endif()
 

openmp/runtime/src/CMakeLists.txt

include_directories(
   ${LIBOMP_SRC_DIR}/i18n
   ${LIBOMP_INC_DIR}
   ${LIBOMP_SRC_DIR}/thirdparty/ittnotify
 )
 if(${LIBOMP_USE_HWLOC})
   include_directories(${LIBOMP_HWLOC_INSTALL_DIR}/include)
 endif()
 
+# Building with time profiling support for libomptarget requires
+# LLVM directory includes.
+if(LIBOMPTARGET_PROFILING_SUPPORT)
+  include_directories(
+    ${LLVM_MAIN_INCLUDE_DIR}
+    ${LLVM_INCLUDE_DIR}
+  )
+endif()
+
 # Getting correct source files to build library
 set(LIBOMP_CXXFILES)
 set(LIBOMP_ASMFILES)
 if(STUBS_LIBRARY)
   set(LIBOMP_CXXFILES kmp_stub.cpp)
 else()
   # Get C++ files
   set(LIBOMP_CXXFILES