Revert "An attempt to abandon omptarget out-of-tree builds."

This reverts commit f2f88f3.
Because our libomptarget implementation for VE requries out-of-tree
builds at the moemnt.  TODO: need to apply this patch with
updates of libomptarget for VE.

Author: kaz7

openmp/CMakeLists.txt

@@ -39,6 +39,8 @@ 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.
@@ -62,6 +64,20 @@ 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_INCLUDE_DIRS)
+  if (LLVM_MAIN_INCLUDE_DIR)
+    list(APPEND LIBOMPTARGET_LLVM_INCLUDE_DIRS ${LLVM_MAIN_INCLUDE_DIR})
+  elseif (EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/../llvm/include)
+    list(APPEND LIBOMPTARGET_LLVM_INCLUDE_DIRS ${CMAKE_CURRENT_SOURCE_DIR}/../llvm/include)
+  endif()
+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."

openmp/README.rst

@@ -243,15 +243,6 @@ These flags are **appended**, they do not overwrite any of the preset flags.
 Options for ``libomptarget``
 ----------------------------
 
-An installed LLVM package is a prerequisite for building ``libomptarget``
-library. So ``libomptarget`` may only be built in two cases:
-
-- As a project of a regular LLVM build via **LLVM_ENABLE_PROJECTS**,
-  **LLVM_EXTERNAL_PROJECTS**, or **LLVM_ENABLE_RUNTIMES** or
-- as a standalone project build that uses a pre-installed LLVM package.
-  In this mode one has to make sure that the default CMake
-  ``find_package(LLVM)`` call `succeeds <https://cmake.org/cmake/help/latest/command/find_package.html#search-procedure>`_.
-
 **LIBOMPTARGET_OPENMP_HEADER_FOLDER** = ``""``
   Path of the folder that contains ``omp.h``.  This is required for testing
   out-of-tree builds.

openmp/libomptarget/cmake/Modules/LibomptargetGetDependencies.cmake

@@ -21,25 +21,6 @@
 
 include (FindPackageHandleStandardArgs)
 
-################################################################################
-# Looking for LLVM...
-################################################################################
-
-if (OPENMP_STANDALONE_BUILD)
-  # Complete LLVM package is required for building libomptarget
-  # in an out-of-tree mode.
-  find_package(LLVM REQUIRED)
-  message(STATUS "Found LLVM ${LLVM_PACKAGE_VERSION}")
-  message(STATUS "Using LLVM in: ${LLVM_DIR}")
-  list(APPEND LIBOMPTARGET_LLVM_INCLUDE_DIRS ${LLVM_INCLUDE_DIRS})
-  list(APPEND CMAKE_MODULE_PATH ${LLVM_CMAKE_DIR})
-  include(AddLLVM)
-else()
-  list(APPEND LIBOMPTARGET_LLVM_INCLUDE_DIRS
-    ${LLVM_MAIN_INCLUDE_DIR} ${LLVM_BINARY_DIR}/include
-    )
-endif()
-
 ################################################################################
 # Looking for libelf...
 ################################################################################
@@ -346,4 +327,27 @@ if (NOT LIBOMPTARGET_CUDA_TOOLKIT_ROOT_DIR_PRESET AND
   endif()
 endif()
 
-set(OPENMP_PTHREAD_LIB ${LLVM_PTHREAD_LIB})
+if (OPENMP_STANDALONE_BUILD)
+  # This duplicates code from llvm/cmake/config-ix.cmake
+  if( WIN32 AND NOT CYGWIN )
+    # We consider Cygwin as another Unix
+    set(PURE_WINDOWS 1)
+  endif()
+
+  # library checks
+  if( NOT PURE_WINDOWS )
+    check_library_exists(pthread pthread_create "" HAVE_LIBPTHREAD)
+  endif()
+
+  if(HAVE_LIBPTHREAD)
+    # We want to find pthreads library and at the moment we do want to
+    # have it reported as '-l<lib>' instead of '-pthread'.
+    # TODO: switch to -pthread once the rest of the build system can deal with it.
+    set(CMAKE_THREAD_PREFER_PTHREAD TRUE)
+    set(THREADS_HAVE_PTHREAD_ARG Off)
+    find_package(Threads REQUIRED)
+    set(OPENMP_PTHREAD_LIB ${CMAKE_THREAD_LIBS_INIT})
+  endif()
+else()
+  set(OPENMP_PTHREAD_LIB ${LLVM_PTHREAD_LIB})
+endif()

openmp/libomptarget/deviceRTLs/amdgcn/CMakeLists.txt

@@ -10,6 +10,32 @@
 #
 ##===----------------------------------------------------------------------===##
 
+find_package(LLVM QUIET CONFIG
+  PATHS
+  $ENV{AOMP}
+  $ENV{HOME}/rocm/aomp
+  /opt/rocm/aomp
+  /usr/lib/rocm/aomp
+  ${LIBOMPTARGET_NVPTX_CUDA_COMPILER_DIR}
+  ${LIBOMPTARGET_NVPTX_CUDA_LINKER_DIR}
+  ${CMAKE_CXX_COMPILER_DIR}
+  NO_DEFAULT_PATH)
+
+if (LLVM_DIR)
+  libomptarget_say("Found LLVM ${LLVM_PACKAGE_VERSION}. Configure: ${LLVM_DIR}/LLVMConfig.cmake")
+else()
+  libomptarget_say("Not building AMDGCN device RTL: AOMP not found")
+  return()
+endif()
+
+set(AOMP_INSTALL_PREFIX ${LLVM_INSTALL_PREFIX})
+
+if (AOMP_INSTALL_PREFIX)
+  set(AOMP_BINDIR ${AOMP_INSTALL_PREFIX}/bin)
+else()
+  set(AOMP_BINDIR ${LLVM_BUILD_BINARY_DIR}/bin)
+endif()
+
 # Copied from nvptx CMakeLists
 if(CMAKE_HOST_SYSTEM_PROCESSOR MATCHES "x86_64")
   set(aux_triple x86_64-unknown-linux-gnu)
@@ -22,20 +48,7 @@ else()
   return()
 endif()
 
-if (LLVM_DIR)
-  # Builds that use pre-installed LLVM have LLVM_DIR set.
-  find_program(CLANG_TOOL clang PATHS ${LLVM_TOOLS_BINARY_DIR} NO_DEFAULT_PATH)
-  find_program(LINK_TOOL llvm-link PATHS ${LLVM_TOOLS_BINARY_DIR}
-    NO_DEFAULT_PATH)
-  find_program(OPT_TOOL opt PATHS ${LLVM_TOOLS_BINARY_DIR} NO_DEFAULT_PATH)
-  libomptarget_say("Building AMDGCN device RTL. Using clang: ${CLANG_TOOL}")
-else()
-  # LLVM in-tree builds may use CMake target names to discover the tools.
-  set(CLANG_TOOL $<TARGET_FILE:clang>)
-  set(LINK_TOOL $<TARGET_FILE:llvm-link>)
-  set(OPT_TOOL $<TARGET_FILE:opt>)
-  libomptarget_say("Building AMDGCN device RTL. Using clang from in-tree build")
-endif()
+libomptarget_say("Building AMDGCN device RTL. LLVM_COMPILER_PATH=${AOMP_BINDIR}")
 
 project(omptarget-amdgcn)
 
@@ -96,7 +109,7 @@ if (DEFINED LIBOMPTARGET_AMDGCN_GFXLIST)
 endif()
 
 macro(add_cuda_bc_library)
-  set(cu_cmd ${CLANG_TOOL}
+  set(cu_cmd ${AOMP_BINDIR}/clang++
     -xc++
     -c
     -std=c++14
@@ -132,7 +145,7 @@ macro(add_cuda_bc_library)
 
   add_custom_command(
     OUTPUT linkout.cuda.${mcpu}.bc
-    COMMAND ${LINK_TOOL} ${bc1_files} -o linkout.cuda.${mcpu}.bc
+    COMMAND ${AOMP_BINDIR}/llvm-link ${bc1_files} -o linkout.cuda.${mcpu}.bc
     DEPENDS ${bc1_files})
 
   list(APPEND bc_files linkout.cuda.${mcpu}.bc)
@@ -147,7 +160,7 @@ foreach(mcpu ${mcpus})
   set(bc_libname lib${libname}-${mcpu}.bc)
   add_custom_command(
     OUTPUT ${bc_libname}
-    COMMAND ${LINK_TOOL} ${bc_files} | ${OPT_TOOL} --always-inline -o ${OUTPUTDIR}/${bc_libname}
+    COMMAND ${AOMP_BINDIR}/llvm-link ${bc_files} | ${AOMP_BINDIR}/opt --always-inline -o ${OUTPUTDIR}/${bc_libname}
     DEPENDS ${bc_files})
 
   add_custom_target(lib${libname}-${mcpu} ALL DEPENDS ${bc_libname})

openmp/libomptarget/src/CMakeLists.txt

@@ -24,19 +24,29 @@ set(LIBOMPTARGET_SRC_FILES ${LIBOMPTARGET_SRC_FILES} PARENT_SCOPE)
 
 include_directories(${LIBOMPTARGET_LLVM_INCLUDE_DIRS})
 
-# Build libomptarget library with libdl dependency.
-add_library(omptarget SHARED ${LIBOMPTARGET_SRC_FILES})
-if (OPENMP_ENABLE_LIBOMPTARGET_PROFILING)
-  # Add LLVMSupport dependency if profiling is enabled.
-  # Linking with LLVM component libraries also requires
-  # aligning the compile flags.
-  llvm_update_compile_flags(omptarget)
+# 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")
+else()
+  set(LLVM_LINK_COMPONENTS
+    Support
+    )
+  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)
-  target_link_libraries(omptarget PRIVATE LLVMSupport)
 endif()
-target_link_libraries(omptarget PRIVATE
-  ${CMAKE_DL_LIBS}
-  "-Wl,--version-script=${CMAKE_CURRENT_SOURCE_DIR}/exports")
+
+# 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