libc/CMakeLists.txt

cmake_minimum_required(VERSION 3.13.4)

# Default to C++17
set(CMAKE_CXX_STANDARD 17)

# Use old version of target_sources command which converts the source
# file paths to full paths.
cmake_policy(SET CMP0076 OLD)
list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules")

# The top-level sourse and binary directories.
set(LIBC_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
set(LIBC_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
# The top-level directory in which libc is being built.
set(LIBC_BUILD_DIR ${CMAKE_CURRENT_BINARY_DIR})

# For a runtimes build we need to manually include tablgen and LLVM directories.
if ("libc" IN_LIST LLVM_ENABLE_RUNTIMES)
  include(TableGen)
  set(LLVM_LIBC_INCLUDE_DIRS ${LLVM_MAIN_INCLUDE_DIR} ${LLVM_BINARY_DIR}/include)
endif()

# Path libc/scripts directory.
set(LIBC_BUILD_SCRIPTS_DIR "${LIBC_SOURCE_DIR}/utils/build_scripts")

# Flags to pass down to the compiler while building the libc functions.
set(LIBC_COMPILE_OPTIONS_DEFAULT "" CACHE STRING "Architecture to tell clang to optimize for (e.g. -march=... or -mcpu=...)")

include(common_libc_tuners.cmake)

list(APPEND LIBC_COMPILE_OPTIONS_DEFAULT ${LIBC_COMMON_TUNE_OPTIONS})

# Check --print-resource-dir to find the compiler resource dir if this flag
# is supported by the compiler.
execute_process(
  OUTPUT_STRIP_TRAILING_WHITESPACE
  COMMAND ${CMAKE_CXX_COMPILER} --print-resource-dir
  RESULT_VARIABLE COMMAND_RETURN_CODE
  OUTPUT_VARIABLE COMPILER_RESOURCE_DIR
)
# Retrieve the host compiler's resource dir.
if(COMMAND_RETURN_CODE EQUAL 0)
  set(COMPILER_RESOURCE_DIR
    "${COMPILER_RESOURCE_DIR}" CACHE PATH "path to compiler resource dir"
  )
  message(STATUS "Set COMPILER_RESOURCE_DIR to "
                 "${COMPILER_RESOURCE_DIR} using --print-resource-dir")
else()
  set(COMPILER_RESOURCE_DIR OFF)
  message(STATUS "COMPILER_RESOURCE_DIR not set
                  --print-resource-dir not supported by host compiler")
endif()

option(LLVM_LIBC_FULL_BUILD "Build and test LLVM libc as if it is the full libc" OFF)
option(LLVM_LIBC_IMPLEMENTATION_DEFINED_TEST_BEHAVIOR "Build LLVM libc tests assuming our implementation-defined behavior" ON)
option(LLVM_LIBC_ENABLE_LINTING "Enables linting of libc source files" OFF)

option(LIBC_GPU_BUILD "Build libc for the GPU. All CPU build options will be ignored." OFF)
set(LIBC_TARGET_TRIPLE "" CACHE STRING "The target triple for the libc build.")

# Defines LIBC_TARGET_ARCHITECTURE and associated macros.
include(LLVMLibCArchitectures)

if(LIBC_TARGET_ARCHITECTURE_IS_GPU)
  include(prepare_libc_gpu_build)
endif()

include(LLVMLibCCheckMPFR)

if(LLVM_LIBC_CLANG_TIDY)
  set(LLVM_LIBC_ENABLE_LINTING ON)
endif()

if(LLVM_LIBC_ENABLE_LINTING)
  if(NOT CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
    set(LLVM_LIBC_ENABLE_LINTING OFF)
    message(WARNING "C++ compiler is not clang++, linting with be disabled.")
  else()
    if (NOT LLVM_LIBC_CLANG_TIDY)
      find_program(LLVM_LIBC_CLANG_TIDY NAMES clang-tidy)
    endif()

    if(LLVM_LIBC_CLANG_TIDY)
      # Check clang-tidy major version.
      execute_process(COMMAND ${LLVM_LIBC_CLANG_TIDY} "--version"
                      OUTPUT_VARIABLE CLANG_TIDY_OUTPUT)
      string(REGEX MATCH "[0-9]+" CLANG_TIDY_VERSION "${CLANG_TIDY_OUTPUT}")
      string(REGEX MATCH "[0-9]+" CLANG_MAJOR_VERSION
             "${CMAKE_CXX_COMPILER_VERSION}")
      if(NOT CLANG_TIDY_VERSION EQUAL CLANG_MAJOR_VERSION)
        set(LLVM_LIBC_ENABLE_LINTING OFF)
        message(WARNING "
          'clang-tidy' (version ${CLANG_TIDY_VERSION}) is not the same as
          'clang' (version ${CLANG_MAJOR_VERSION}).  Linting will
          be disabled.

          The path to the clang-tidy binary can be set manually by passing
          -DLLVM_LIBC_CLANG_TIDY=<path/to/clang-tidy> to CMake.")
      endif()
    else()
      message(FATAL_ERROR "
        Linting is enabled but 'clang-tidy' is not found!

        The path to the clang-tidy binary can be set manually by passing
        -DLLVM_LIBC_CLANG_TIDY=<path/to/clang-tidy> to CMake.

        To disable linting set LLVM_LIBC_ENABLE_LINTING to OFF
        (pass -DLLVM_LIBC_ENABLE_LINTING=OFF to cmake).")
    endif()
  endif()
endif()

option(LLVM_LIBC_INCLUDE_SCUDO "Include the SCUDO standalone as the allocator for LLVM libc" OFF)
if(LLVM_LIBC_INCLUDE_SCUDO)
  if (NOT "compiler-rt" IN_LIST LLVM_ENABLE_PROJECTS)
    message(FATAL_ERROR "SCUDO cannot be included without adding compiler-rt to LLVM_ENABLE_PROJECTS")
  endif()
endif()

option(LIBC_INCLUDE_DOCS "Build the libc documentation." ${LLVM_INCLUDE_DOCS})

include(CMakeParseArguments)
include(LLVMLibCCheckCpuFeatures)
include(LLVMLibCRules)

if(EXISTS "${LIBC_SOURCE_DIR}/config/${LIBC_TARGET_OS}/${LIBC_TARGET_ARCHITECTURE}/entrypoints.txt")
  set(entrypoint_file "${LIBC_SOURCE_DIR}/config/${LIBC_TARGET_OS}/${LIBC_TARGET_ARCHITECTURE}/entrypoints.txt")
elseif(EXISTS "${LIBC_SOURCE_DIR}/config/${LIBC_TARGET_OS}/entrypoints.txt")
  set(entrypoint_file "${LIBC_SOURCE_DIR}/config/${LIBC_TARGET_OS}/entrypoints.txt")
else()
  message(FATAL_ERROR "entrypoints.txt file for the target platform '${LIBC_TARGET_OS}/${LIBC_TARGET_ARCHITECTURE}' not found.")
endif()
include(${entrypoint_file})

if(EXISTS "${LIBC_SOURCE_DIR}/config/${LIBC_TARGET_OS}/${LIBC_TARGET_ARCHITECTURE}/headers.txt")
  include("${LIBC_SOURCE_DIR}/config/${LIBC_TARGET_OS}/${LIBC_TARGET_ARCHITECTURE}/headers.txt")
elseif(EXISTS "${LIBC_SOURCE_DIR}/config/${LIBC_TARGET_OS}/headers.txt")
  include("${LIBC_SOURCE_DIR}/config/${LIBC_TARGET_OS}/headers.txt")
endif()

set(TARGET_ENTRYPOINT_NAME_LIST "")
foreach(entrypoint IN LISTS TARGET_LLVMLIBC_ENTRYPOINTS)
  string(FIND ${entrypoint} "." last_dot_loc REVERSE)
  if(${last_dot_loc} EQUAL -1)
    message(FATAL "Invalid entrypoint target name ${entrypoint}; Expected a '.' "
                  "(dot) in the name.")
  endif()
  math(EXPR name_loc "${last_dot_loc} + 1")
  string(SUBSTRING ${entrypoint} ${name_loc} -1 entrypoint_name)
  list(APPEND TARGET_ENTRYPOINT_NAME_LIST ${entrypoint_name})
endforeach()

if(LLVM_LIBC_FULL_BUILD)
  # We need to set up hdrgen first since other targets depend on it.
  add_subdirectory(utils/LibcTableGenUtil)
  add_subdirectory(utils/HdrGen)
endif()

set(LIBC_TARGET)
set(LIBC_COMPONENT)
set(LIBC_INSTALL_DEPENDS)
set(LIBC_INSTALL_TARGET)
if(LLVM_LIBC_FULL_BUILD)
  set(LIBC_TARGET libc)
  set(LIBC_COMPONENT libc)
  set(LIBC_INSTALL_DEPENDS "install-libc-static-archives;install-libc-headers")
  if(NOT LIBC_TARGET_OS_IS_BAREMETAL)
    # For now we will disable libc-startup installation for baremetal. The
    # correct way to do it would be to make a hookable startup for baremetal
    # and install it as part of the libc installation.
    list(APPEND LIBC_INSTALL_DEPENDS "libc-startup")
  endif()
  set(LIBC_INSTALL_TARGET install-libc)
  if(LIBC_TARGET_ARCHITECTURE_IS_GPU)
    set(LIBC_ARCHIVE_NAME cgpu)
  else()
    set(LIBC_ARCHIVE_NAME c)
  endif()
else()
  set(LIBC_TARGET llvmlibc)
  set(LIBC_COMPONENT llvmlibc)
  set(LIBC_INSTALL_DEPENDS install-libc-static-archives)
  set(LIBC_INSTALL_TARGET install-llvmlibc)
  set(LIBC_ARCHIVE_NAME llvmlibc)
endif()

add_subdirectory(include)
add_subdirectory(config)
add_subdirectory(src)
add_subdirectory(utils)

if(LLVM_LIBC_FULL_BUILD)
  # The startup system can potentially depend on the library components so add
  # it after the library implementation directories.
  add_subdirectory(startup)
endif()

# The lib and test directories are added at the very end as tests
# and libraries potentially draw from the components present in all
# of the other directories.
# TODO: Add testing support for the libc GPU target.
add_subdirectory(lib)
if(LLVM_INCLUDE_TESTS AND NOT LIBC_TARGET_ARCHITECTURE_IS_GPU)
  add_subdirectory(test)
  add_subdirectory(fuzzing)
endif()

if(LIBC_INCLUDE_BENCHMARKS)
  add_subdirectory(benchmarks)
endif()

if (LIBC_INCLUDE_DOCS)
  add_subdirectory(docs)
endif()


if(LLVM_LIBC_FULL_BUILD)
  add_llvm_install_targets(
    install-libc-headers
    DEPENDS libc-headers
    COMPONENT libc-headers
  )
endif()

add_llvm_install_targets(
  ${LIBC_INSTALL_TARGET}
  DEPENDS ${LIBC_INSTALL_DEPENDS}
  COMPONENT ${LIBC_COMPONENT}
)