[Flang] LLVM_ENABLE_RUNTIMES=flang-rt

clang/lib/Driver/ToolChains/Flang.cpp

@@ -342,11 +342,15 @@ static void processVSRuntimeLibrary(const ToolChain &TC, const ArgList &Args,
                                     ArgStringList &CmdArgs) {
   assert(TC.getTriple().isKnownWindowsMSVCEnvironment() &&
          "can only add VS runtime library on Windows!");
-  // if -fno-fortran-main has been passed, skip linking Fortran_main.a
-  if (TC.getTriple().isKnownWindowsMSVCEnvironment()) {
-    CmdArgs.push_back(Args.MakeArgString(
-        "--dependent-lib=" + TC.getCompilerRTBasename(Args, "builtins")));
-  }
+
+  // Flang/Clang (including clang-cl) -compiled programs targeting the MSVC ABI
+  // should only depend on msv(u)crt. LLVM still emits libgcc/compiler-rt
+  // functions in some cases like 128-bit integer math (__udivti3, __modti3,
+  // __fixsfti, __floattidf, ...) that msvc does not support. We are injecting a
+  // dependency to Compiler-RT's builtin library where these are implemented.
+  CmdArgs.push_back(Args.MakeArgString(
+      "--dependent-lib=" + TC.getCompilerRTBasename(Args, "builtins")));
+
   unsigned RTOptionID = options::OPT__SLASH_MT;
   if (auto *rtl = Args.getLastArg(options::OPT_fms_runtime_lib_EQ)) {
     RTOptionID = llvm::StringSwitch<unsigned>(rtl->getValue())

flang-rt/.clang-tidy

@@ -0,0 +1,2 @@
+Checks: '-llvm-include-order,readability-braces-around-statements,-readability-identifier-naming,-clang-diagnostic-*'
+InheritParentConfig: true

flang-rt/CMakeLists.txt

@@ -0,0 +1,248 @@
+#===-- 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.
+#
+#===------------------------------------------------------------------------===#
+
+if (NOT LLVM_RUNTIMES_BUILD)
+  message(FATAL_ERROR "Use this CMakeLists.txt from LLVM's runtimes build system.
+      Example:
+        cmake <llvm-project>/runtimes -DLLVM_ENABLE_RUNTIMES=flang-rt
+    ")
+endif ()
+
+set(LLVM_SUBPROJECT_TITLE "Flang-RT")
+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 "${LLVM_VERSION_MAJOR}.${LLVM_VERSION_MINOR}")
+
+    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(GetToolchainDirs)
+include(FlangCommon)
+include(HandleCompilerRT)
+include(ExtendPath)
+
+
+############################
+# Build Mode Introspection #
+############################
+
+# Determine whether we are in the runtimes/runtimes-bins directory of a
+# bootstrap build.
+set(LLVM_TREE_AVAILABLE OFF)
+if (LLVM_LIBRARY_OUTPUT_INTDIR AND LLVM_RUNTIME_OUTPUT_INTDIR AND PACKAGE_VERSION)
+  set(LLVM_TREE_AVAILABLE ON)
+endif()
+
+# Path to LLVM development tools (FileCheck, llvm-lit, not, ...)
+set(LLVM_TOOLS_DIR "${LLVM_BINARY_DIR}/bin")
+
+# Determine build and install paths.
+# The build path is absolute, but the install dir is relative, CMake's install
+# command has to apply CMAKE_INSTALL_PREFIX itself.
+get_toolchain_library_subdir(toolchain_lib_subdir)
+if (LLVM_TREE_AVAILABLE)
+  # In a bootstrap build emit the libraries into a default search path in the
+  # build directory of the just-built compiler. This allows using the
+  # just-built compiler without specifying paths to runtime libraries.
+  #
+  # Despite Clang in the name, get_clang_resource_dir does not depend on Clang
+  # being added to the build. Flang uses the same resource dir as clang.
+  include(GetClangResourceDir)
+  get_clang_resource_dir(FLANG_RT_OUTPUT_RESOURCE_DIR PREFIX "${LLVM_LIBRARY_OUTPUT_INTDIR}/..")
+  get_clang_resource_dir(FLANG_RT_INSTALL_RESOURCE_PATH)
+
+  extend_path(FLANG_RT_OUTPUT_RESOURCE_LIB_DIR "${FLANG_RT_OUTPUT_RESOURCE_DIR}" "${toolchain_lib_subdir}")
+else ()
+  # In a standalone runtimes build, do not write into LLVM_BINARY_DIR. It may be
+  # read-only and/or shared by multiple runtimes with different build
+  # configurations (e.g. Debug/Release). Use the runtime's own lib dir like any
+  # non-toolchain library.
+  # For the install prefix, still use the resource dir assuming that Flang will
+  # be installed there using the same prefix. This is to not have a difference
+  # between bootstrap and standalone runtimes builds.
+  set(FLANG_RT_OUTPUT_RESOURCE_DIR "${CMAKE_CURRENT_BINARY_DIR}")
+  set(FLANG_RT_INSTALL_RESOURCE_PATH "lib${LLVM_LIBDIR_SUFFIX}/clang/${LLVM_VERSION_MAJOR}")
+
+  extend_path(FLANG_RT_OUTPUT_RESOURCE_LIB_DIR "${FLANG_RT_OUTPUT_RESOURCE_DIR}" "lib${LLVM_LIBDIR_SUFFIX}")
+endif ()
+extend_path(FLANG_RT_INSTALL_RESOURCE_LIB_PATH "${FLANG_RT_INSTALL_RESOURCE_PATH}" "${toolchain_lib_subdir}")
+cmake_path(NORMAL_PATH FLANG_RT_OUTPUT_RESOURCE_DIR)
+cmake_path(NORMAL_PATH FLANG_RT_INSTALL_RESOURCE_PATH)
+cmake_path(NORMAL_PATH FLANG_RT_OUTPUT_RESOURCE_LIB_DIR)
+cmake_path(NORMAL_PATH FLANG_RT_INSTALL_RESOURCE_LIB_PATH)
+
+
+#################
+# Build Options #
+#################
+
+# Important: flang-rt user options must be prefixed with "FLANG_RT_". Variables
+# with this prefix will be forwarded in bootstrap builds.
+
+option(FLANG_RT_INCLUDE_TESTS "Generate build targets for the flang-rt unit and regression-tests." "${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)
+  # Support for GPUs disabled
+elseif (FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT STREQUAL "CUDA")
+  # Support for CUDA
+  set(FLANG_RT_LIBCUDACXX_PATH "" CACHE PATH "Path to libcu++ package installation")
+  option(FLANG_RT_CUDA_RUNTIME_PTX_WITHOUT_GLOBAL_VARS "Do not compile global variables' definitions when producing PTX library" OFF)
+elseif (FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT STREQUAL "OpenMP")
+  # Support for OpenMP offloading
+  set(FLANG_RT_DEVICE_ARCHITECTURES "all" CACHE STRING
+      "List of OpenMP device architectures to be used to compile the Fortran runtime (e.g. 'gfx1103;sm_90')"
+    )
+
+  if (FLANG_RT_DEVICE_ARCHITECTURES STREQUAL "all")
+    # TODO: support auto detection on the build system.
+    set(all_amdgpu_architectures
+      "gfx700;gfx701;gfx801;gfx803;gfx900;gfx902;gfx906"
+      "gfx908;gfx90a;gfx90c;gfx940;gfx1010;gfx1030"
+      "gfx1031;gfx1032;gfx1033;gfx1034;gfx1035;gfx1036"
+      "gfx1100;gfx1101;gfx1102;gfx1103;gfx1150;gfx1151"
+      "gfx1152;gfx1153")
+    set(all_nvptx_architectures
+      "sm_35;sm_37;sm_50;sm_52;sm_53;sm_60;sm_61;sm_62"
+      "sm_70;sm_72;sm_75;sm_80;sm_86;sm_89;sm_90")
+    set(all_gpu_architectures
+      "${all_amdgpu_architectures};${all_nvptx_architectures}")
+      set(FLANG_RT_DEVICE_ARCHITECTURES ${all_gpu_architectures})
+  endif()
+  list(REMOVE_DUPLICATES FLANG_RT_DEVICE_ARCHITECTURES)
+else ()
+  message(FATAL_ERROR "Invalid value '${FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT}' for FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT; must be empty, 'CUDA', or 'OpenMP'")
+endif ()
+
+
+option(FLANG_RT_ENABLE_CUF "Compile CUDA Fortran runtime sources" OFF)
+if (FLANG_RT_ENABLE_CUF)
+  find_package(CUDAToolkit REQUIRED)
+endif()
+
+
+########################
+# System Introspection #
+########################
+
+include(CheckCXXSymbolExists)
+include(CheckCXXSourceCompiles)
+check_cxx_symbol_exists(strerror_r string.h HAVE_STRERROR_R)
+# Can't use symbol exists here as the function is overloaded in C++
+check_cxx_source_compiles(
+  "#include <string.h>
+   int main() {
+     char buf[4096];
+     return strerror_s(buf, 4096, 0);
+   }
+  "
+  HAVE_DECL_STRERROR_S)
+
+
+# Search for clang_rt.builtins library. Need in addition to msvcrt.
+if (WIN32)
+  find_compiler_rt_library(builtins FLANG_RT_BUILTINS_LIBRARY)
+endif ()
+
+
+# Check whether the compiler can undefine a macro using the "-U" flag.
+# Aternatively, we could use
+#   CMAKE_CXX_COMPILER_FRONTEND_VARIANT STREQUAL "GNU"
+# but some older versions of CMake don't define it for GCC itself.
+check_cxx_compiler_flag("-UTESTFLAG" FLANG_RT_SUPPORTS_UNDEFINE_FLAG)
+
+
+#####################
+# Build Preparation #
+#####################
+
+if (FLANG_RT_EXPERIMENTAL_OFFLOAD_SUPPORT AND FLANG_RT_INCLUDE_TESTS)
+  # If Fortran runtime is built as CUDA library, the linking
+  # of targets that link flang-rt must be done
+  # with CUDA_RESOLVE_DEVICE_SYMBOLS.
+  # CUDA language must be enabled for CUDA_RESOLVE_DEVICE_SYMBOLS
+  # to take effect.
+  enable_language(CUDA)
+endif()
+
+
+# C++17 is required for flang-rt; user or other runtimes may override this.
+# GTest included later also requires C++17.
+set(CMAKE_CXX_STANDARD 17 CACHE STRING "C++ standard to conform to")
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
+
+
+configure_file(cmake/config.h.cmake.in config.h)
+
+
+# The bootstrap build will create a phony target with the same as the top-level
+# directory ("flang-rt") and delegate it to the runtimes build dir.
+# AddFlangRT will add all non-EXCLUDE_FROM_ALL targets to it.
+add_custom_target(flang-rt)
+
+
+###################
+# Build Artifacts #
+###################
+
+add_subdirectory(lib)
+
+if (FLANG_RT_INCLUDE_TESTS)
+  add_subdirectory(unittests)
+  add_subdirectory(test)
+else ()
+  add_custom_target(check-flang-rt)
+endif()

flang-rt/CODE_OWNERS.TXT

@@ -0,0 +1,14 @@
+This file is a list of the people responsible for ensuring that patches for a
+particular part of Flang are reviewed, either by themself or by someone else.
+They are also the gatekeepers for their part of Flang, with the final word on
+what goes in or not.
+
+The list is sorted by surname and formatted to allow easy grepping and
+beautification by scripts. The fields are: name (N), email (E), web-address
+(W), PGP key ID and fingerprint (P), description (D), snail-mail address
+(S) and (I) IRC handle. Each entry should contain at least the (N), (E) and
+(D) fields.
+
+N: Steve Scalpone
+E: [email protected]
+D: Anything not covered by others