[llvm-branch-commits] [clang] [flang] [lld] [llvm] [Flang] LLVM_ENABLE_RUNTIMES=flang-rt (PR #110217)

[via llvm-branch-commits]

================
@@ -0,0 +1,210 @@
+#===-- 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 instructions for the flang-rt library. This is file is intended to be
+# included using the LLVM_ENABLE_RUNTIMES mechanism.
+#
+#===------------------------------------------------------------------------===#
+
+set(LLVM_SUBPROJECT_TITLE "Fortran Runtime")
+set(FLANG_RT_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}")
+set(FLANG_RT_BINARY_DIR "${CMAKE_CURRENT_BINARY_DIR}")
+set(FLANG_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../flang")
+
+
+# CMake 3.24 is the first version of CMake that directly recognizes Flang.
+# LLVM's requirement is only CMake 3.20, teach CMake 3.20-3.23 how to use Flang.
+if (CMAKE_VERSION VERSION_LESS "3.24")
+  cmake_path(GET CMAKE_Fortran_COMPILER STEM _Fortran_COMPILER_STEM)
+  if (_Fortran_COMPILER_STEM STREQUAL "flang-new" OR _Fortran_COMPILER_STEM STREQUAL "flang")
+    include(CMakeForceCompiler)
+    CMAKE_FORCE_Fortran_COMPILER("${CMAKE_Fortran_COMPILER}" "LLVMFlang")
+
+    set(CMAKE_Fortran_COMPILER_ID "LLVMFlang")
+    set(CMAKE_Fortran_COMPILER_VERSION "20.0")
+
+    set(CMAKE_Fortran_SUBMODULE_SEP "-")
+    set(CMAKE_Fortran_SUBMODULE_EXT ".mod")
+
+    set(CMAKE_Fortran_PREPROCESS_SOURCE
+      "<CMAKE_Fortran_COMPILER> -cpp <DEFINES> <INCLUDES> <FLAGS> -E <SOURCE> > <PREPROCESSED_SOURCE>")
+
+    set(CMAKE_Fortran_FORMAT_FIXED_FLAG "-ffixed-form")
+    set(CMAKE_Fortran_FORMAT_FREE_FLAG "-ffree-form")
+
+    set(CMAKE_Fortran_MODDIR_FLAG "-module-dir")
+
+    set(CMAKE_Fortran_COMPILE_OPTIONS_PREPROCESS_ON "-cpp")
+    set(CMAKE_Fortran_COMPILE_OPTIONS_PREPROCESS_OFF "-nocpp")
+    set(CMAKE_Fortran_POSTPROCESS_FLAG "-ffixed-line-length-72")
+
+    set(CMAKE_Fortran_COMPILE_OPTIONS_TARGET "--target=")
+
+    set(CMAKE_Fortran_LINKER_WRAPPER_FLAG "-Wl,")
+    set(CMAKE_Fortran_LINKER_WRAPPER_FLAG_SEP ",")
+  endif ()
+endif ()
+enable_language(Fortran)
+
+
+list(APPEND CMAKE_MODULE_PATH
+    "${FLANG_RT_SOURCE_DIR}/cmake/modules"
+    "${FLANG_SOURCE_DIR}/cmake/modules"
+  )
+include(AddFlangRT)
+include(FlangCommon)
+
+
+############################
+# Build Mode Introspection #
+############################
+
+# Setting these variables from an LLVM build is sufficient that flang-rt can
+# construct the output paths, so it can behave as if it were in-tree here.
+set(LLVM_TREE_AVAILABLE OFF)
+if (LLVM_LIBRARY_OUTPUT_INTDIR AND LLVM_RUNTIME_OUTPUT_INTDIR AND PACKAGE_VERSION)
+  # This is a bootstap build
+  set(LLVM_TREE_AVAILABLE ON)
+endif()
+
+if (LLVM_TREE_AVAILABLE)
+  # Despite Clang in the name, get_clang_resource_dir does not depend on Clang being added to the build
+  # flang-new uses the same resource dir as clang.
+  include(GetClangResourceDir)
+  get_clang_resource_dir(FLANG_RT_BUILD_LIB_DIR PREFIX "${LLVM_LIBRARY_OUTPUT_INTDIR}/.." SUBDIR "lib${LLVM_LIBDIR_SUFFIX}")
+  get_clang_resource_dir(FLANG_RT_INSTALL_LIB_DIR SUBDIR "lib${LLVM_LIBDIR_SUFFIX}") # No prefix, CMake's install command finds the install prefix itself
+else ()
+  set(FLANG_RT_BUILD_LIB_DIR "${LLVM_LIBRARY_OUTPUT_INTDIR}")
+  set(FLANG_RT_INSTALL_LIB_DIR "lib${LLVM_LIBDIR_SUFFIX}")
+endif ()
+
+if (DEFINED WIN32)
+  set(FLANG_RT_BUILD_LIB_DIR "${FLANG_RT_BUILD_LIB_DIR}/windows")
+  set(FLANG_RT_INSTALL_LIB_DIR "${FLANG_RT_INSTALL_LIB_DIR}/windows")
+elseif (LLVM_ENABLE_PER_TARGET_RUNTIME_DIR)
+  set(FLANG_RT_BUILD_LIB_DIR "${FLANG_RT_BUILD_LIB_DIR}/${LLVM_TARGET_TRIPLE}")
+  set(FLANG_RT_INSTALL_LIB_DIR "${FLANG_RT_INSTALL_LIB_DIR}/${LLVM_TARGET_TRIPLE}")
+endif ()
+
+
+#################
+# Build Options #
+#################
+
+# Important: flang-rt user options must be prefixed with "FLANG_RT_". Variables
+# with this prefix will be forwarded in bootstrap builds.
+
+option(FLANG_RT_INCLUDE_TESTS "Generate build targets for the flang-rt unit and regression-tests." "${LLVM_INCLUDE_TESTS}")
+
+
+set(FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT "" CACHE STRING "Compile flang-rt with GPU support (CUDA or OpenMP)")
+set_property(CACHE FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT PROPERTY STRINGS
+    ""
+    CUDA
+    OpenMP
+  )
+if (NOT FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT)
+elseif (FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT STREQUAL "CUDA")
----------------
h-vetinari wrote:

If the first if branch is intentionally empty, maybe add a comment to that effect?

https://github.com/llvm/llvm-project/pull/110217