[OpenMP] Fixed the test environment when building along with LLVM

[tianshilei1992]

Summary

Currently all built libraries in OpenMP are anywhere if building along
with LLVM. It is not an issue if we don't execute any test. However, almost all
tests for libomptarget fails because in the lit configuration, we only set
<build_dir>/libomptarget to LD_LIBRARY_PATH and LIBRARY_PATH. Since those
libraries are everywhere, clang can no longer find libomptarget.so or those
deviceRTLs anymore.

In this patch, we set a unified path for all built libraries, no matter whether
it is built along with LLVM or not. In this way, our lit configuration can work
propoerly.

[jdoerfert]

LGTM

openmp/libomptarget/CMakeLists.txt

 ##===----------------------------------------------------------------------===##
-# 
+#
 # 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
-# 
+#
 ##===----------------------------------------------------------------------===##
 #
 # Build offloading library and related plugins.
 #
 ##===----------------------------------------------------------------------===##
 
 if("${CMAKE_SOURCE_DIR}" STREQUAL "${CMAKE_CURRENT_SOURCE_DIR}")
   message(FATAL_ERROR "Direct configuration not supported, please use parent directory!")
 endif()
 
 # Add cmake directory to search for custom cmake functions.
 set(CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules ${CMAKE_MODULE_PATH})
 
-if(OPENMP_STANDALONE_BUILD)
-  # Build all libraries into a common place so that tests can find them.
-  set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
-  set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
-endif()
+# Set the path of all resulting libraries to a unified location so that it can
+# be used for testing.
+set(LIBOMPTARGET_LIBRARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
+set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LIBOMPTARGET_LIBRARY_DIR})
+set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LIBOMPTARGET_LIBRARY_DIR})
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${LIBOMPTARGET_LIBRARY_DIR})
 
 # 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

 
 set(LIBOMPTARGET_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/include)
 include_directories(${LIBOMPTARGET_INCLUDE_DIR})
 
 # Build target agnostic offloading library.
 set(LIBOMPTARGET_SRC_DIR ${CMAKE_CURRENT_SOURCE_DIR}/src)
 add_subdirectory(${LIBOMPTARGET_SRC_DIR})
 
-# Retrieve the path to the resulting library so that it can be used for 
-# testing.
-get_target_property(LIBOMPTARGET_LIBRARY_DIR omptarget LIBRARY_OUTPUT_DIRECTORY)
-if(NOT LIBOMPTARGET_LIBRARY_DIR)
-  set(LIBOMPTARGET_LIBRARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
-endif()
-
 # Definitions for testing, for reuse when testing libomptarget-nvptx.
 if(OPENMP_STANDALONE_BUILD)
   set(LIBOMPTARGET_OPENMP_HEADER_FOLDER "${CMAKE_CURRENT_BINARY_DIR}/../runtime/src" CACHE STRING
     "Path to folder containing omp.h")
   set(LIBOMPTARGET_OPENMP_HOST_RTL_FOLDER "${CMAKE_CURRENT_BINARY_DIR}/../runtime/src" CACHE STRING
     "Path to folder containing libomp.so")
 else()
   set(LIBOMPTARGET_OPENMP_HEADER_FOLDER "${CMAKE_CURRENT_BINARY_DIR}/../runtime/src")

openmp/libomptarget/src/CMakeLists.txt

set(LLVM_LINK_COMPONENTS
     )
   add_llvm_library(omptarget SHARED ${LIBOMPTARGET_SRC_FILES}
       LINK_LIBS ${CMAKE_DL_LIBS}
       "-Wl,--version-script=${CMAKE_CURRENT_SOURCE_DIR}/exports"
       )
   target_compile_definitions(omptarget PUBLIC OMPTARGET_PROFILE_ENABLED)
 endif()
 
+# libomptarget needs to be set separately because add_llvm_library doesn't
+# conform with location configuration of its parent scope.
+set_target_properties(omptarget
+  PROPERTIES
+  LIBRARY_OUTPUT_DIRECTORY ${LIBOMPTARGET_LIBRARY_DIR})
+
 # Install libomptarget under the lib destination folder.
 install(TARGETS omptarget LIBRARY COMPONENT omptarget
   DESTINATION "${OPENMP_INSTALL_LIBDIR}")