llvm-project/compiler-rt/cmake/config-ix.cmake

include(CMakePushCheckState)
include(CheckCXXCompilerFlag)
include(CheckLibraryExists)
include(CheckSymbolExists)
include(TestBigEndian)

function(check_linker_flag flag out_var)
  cmake_push_check_state()
  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${flag}")
  check_cxx_compiler_flag("" ${out_var})
  cmake_pop_check_state()
endfunction()

# CodeGen options.
check_cxx_compiler_flag(-fPIC                COMPILER_RT_HAS_FPIC_FLAG)
check_cxx_compiler_flag(-fPIE                COMPILER_RT_HAS_FPIE_FLAG)
check_cxx_compiler_flag(-fno-builtin         COMPILER_RT_HAS_FNO_BUILTIN_FLAG)
check_cxx_compiler_flag(-fno-exceptions      COMPILER_RT_HAS_FNO_EXCEPTIONS_FLAG)
check_cxx_compiler_flag(-fomit-frame-pointer COMPILER_RT_HAS_FOMIT_FRAME_POINTER_FLAG)
check_cxx_compiler_flag(-funwind-tables      COMPILER_RT_HAS_FUNWIND_TABLES_FLAG)
check_cxx_compiler_flag(-fno-stack-protector COMPILER_RT_HAS_FNO_STACK_PROTECTOR_FLAG)
check_cxx_compiler_flag(-fno-sanitize=safe-stack COMPILER_RT_HAS_FNO_SANITIZE_SAFE_STACK_FLAG)
check_cxx_compiler_flag(-fvisibility=hidden  COMPILER_RT_HAS_FVISIBILITY_HIDDEN_FLAG)
check_cxx_compiler_flag(-fno-rtti            COMPILER_RT_HAS_FNO_RTTI_FLAG)
check_cxx_compiler_flag(-ffreestanding       COMPILER_RT_HAS_FFREESTANDING_FLAG)
check_cxx_compiler_flag("-Werror -fno-function-sections" COMPILER_RT_HAS_FNO_FUNCTION_SECTIONS_FLAG)
check_cxx_compiler_flag(-std=c++11           COMPILER_RT_HAS_STD_CXX11_FLAG)
check_cxx_compiler_flag(-ftls-model=initial-exec COMPILER_RT_HAS_FTLS_MODEL_INITIAL_EXEC)
check_cxx_compiler_flag(-fno-lto             COMPILER_RT_HAS_FNO_LTO_FLAG)
check_cxx_compiler_flag("-Werror -msse3" COMPILER_RT_HAS_MSSE3_FLAG)
check_cxx_compiler_flag(-std=c99             COMPILER_RT_HAS_STD_C99_FLAG)
check_cxx_compiler_flag(--sysroot=.          COMPILER_RT_HAS_SYSROOT_FLAG)

if(NOT WIN32 AND NOT CYGWIN)
  # MinGW warns if -fvisibility-inlines-hidden is used.
  check_cxx_compiler_flag("-fvisibility-inlines-hidden" COMPILER_RT_HAS_FVISIBILITY_INLINES_HIDDEN_FLAG)
endif()

check_cxx_compiler_flag(/GR COMPILER_RT_HAS_GR_FLAG)
check_cxx_compiler_flag(/GS COMPILER_RT_HAS_GS_FLAG)
check_cxx_compiler_flag(/MT COMPILER_RT_HAS_MT_FLAG)
check_cxx_compiler_flag(/Oy COMPILER_RT_HAS_Oy_FLAG)

# Debug info flags.
check_cxx_compiler_flag(-gline-tables-only COMPILER_RT_HAS_GLINE_TABLES_ONLY_FLAG)
check_cxx_compiler_flag(-g COMPILER_RT_HAS_G_FLAG)
check_cxx_compiler_flag(/Zi COMPILER_RT_HAS_Zi_FLAG)

# Warnings.
check_cxx_compiler_flag(-Wall COMPILER_RT_HAS_WALL_FLAG)
check_cxx_compiler_flag(-Werror COMPILER_RT_HAS_WERROR_FLAG)
check_cxx_compiler_flag("-Werror -Wframe-larger-than=512" COMPILER_RT_HAS_WFRAME_LARGER_THAN_FLAG)
check_cxx_compiler_flag("-Werror -Wglobal-constructors"   COMPILER_RT_HAS_WGLOBAL_CONSTRUCTORS_FLAG)
check_cxx_compiler_flag("-Werror -Wc99-extensions"     COMPILER_RT_HAS_WC99_EXTENSIONS_FLAG)
check_cxx_compiler_flag("-Werror -Wgnu"                COMPILER_RT_HAS_WGNU_FLAG)
check_cxx_compiler_flag("-Werror -Wnon-virtual-dtor"   COMPILER_RT_HAS_WNON_VIRTUAL_DTOR_FLAG)
check_cxx_compiler_flag("-Werror -Wvariadic-macros"    COMPILER_RT_HAS_WVARIADIC_MACROS_FLAG)

check_cxx_compiler_flag(/W3 COMPILER_RT_HAS_W3_FLAG)
check_cxx_compiler_flag(/WX COMPILER_RT_HAS_WX_FLAG)
check_cxx_compiler_flag(/wd4146 COMPILER_RT_HAS_WD4146_FLAG)
check_cxx_compiler_flag(/wd4291 COMPILER_RT_HAS_WD4291_FLAG)
check_cxx_compiler_flag(/wd4391 COMPILER_RT_HAS_WD4391_FLAG)
check_cxx_compiler_flag(/wd4722 COMPILER_RT_HAS_WD4722_FLAG)
check_cxx_compiler_flag(/wd4800 COMPILER_RT_HAS_WD4800_FLAG)

# Symbols.
check_symbol_exists(__func__ "" COMPILER_RT_HAS_FUNC_SYMBOL)

# Libraries.
check_library_exists(c fopen "" COMPILER_RT_HAS_LIBC)
check_library_exists(dl dlopen "" COMPILER_RT_HAS_LIBDL)
check_library_exists(rt shm_open "" COMPILER_RT_HAS_LIBRT)
check_library_exists(m pow "" COMPILER_RT_HAS_LIBM)
check_library_exists(pthread pthread_create "" COMPILER_RT_HAS_LIBPTHREAD)
check_library_exists(stdc++ __cxa_throw "" COMPILER_RT_HAS_LIBSTDCXX)

# Linker flags.
if(ANDROID)
  check_linker_flag("-Wl,-z,global" COMPILER_RT_HAS_Z_GLOBAL)
  check_library_exists(log __android_log_write "" COMPILER_RT_HAS_LIBLOG)
endif()

# Architectures.

# List of all architectures we can target.
set(COMPILER_RT_SUPPORTED_ARCH)

# Try to compile a very simple source file to ensure we can target the given
# platform. We use the results of these tests to build only the various target
# runtime libraries supported by our current compilers cross-compiling
# abilities.
set(SIMPLE_SOURCE ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/simple.cc)
file(WRITE ${SIMPLE_SOURCE} "#include <stdlib.h>\n#include <limits>\nint main() {}\n")

function(check_compile_definition def argstring out_var)
  if("${def}" STREQUAL "")
    set(${out_var} TRUE PARENT_SCOPE)
    return()
  endif()
  cmake_push_check_state()
  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${argstring}")
  check_symbol_exists(${def} "" ${out_var})
  cmake_pop_check_state()
endfunction()

# test_target_arch(<arch> <def> <target flags...>)
# Checks if architecture is supported: runs host compiler with provided
# flags to verify that:
#   1) <def> is defined (if non-empty)
#   2) simple file can be successfully built.
# If successful, saves target flags for this architecture.
macro(test_target_arch arch def)
  set(TARGET_${arch}_CFLAGS ${ARGN})
  set(argstring "")
  foreach(arg ${ARGN})
    set(argstring "${argstring} ${arg}")
  endforeach()
  check_compile_definition("${def}" "${argstring}" HAS_${arch}_DEF)
  if(NOT HAS_${arch}_DEF)
    set(CAN_TARGET_${arch} FALSE)
  else()
    set(argstring "${CMAKE_EXE_LINKER_FLAGS} ${argstring}")
    try_compile(CAN_TARGET_${arch} ${CMAKE_BINARY_DIR} ${SIMPLE_SOURCE}
                COMPILE_DEFINITIONS "${TARGET_${arch}_CFLAGS}"
                OUTPUT_VARIABLE TARGET_${arch}_OUTPUT
                CMAKE_FLAGS "-DCMAKE_EXE_LINKER_FLAGS:STRING=${argstring}")
  endif()
  if(${CAN_TARGET_${arch}})
    list(APPEND COMPILER_RT_SUPPORTED_ARCH ${arch})
  elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "${arch}" AND
         COMPILER_RT_HAS_EXPLICIT_DEFAULT_TARGET_TRIPLE)
    # Bail out if we cannot target the architecture we plan to test.
    message(FATAL_ERROR "Cannot compile for ${arch}:\n${TARGET_${arch}_OUTPUT}")
  endif()
endmacro()

# Add $arch as supported with no additional flags.
macro(add_default_target_arch arch)
  set(TARGET_${arch}_CFLAGS "")
  set(CAN_TARGET_${arch} 1)
  list(APPEND COMPILER_RT_SUPPORTED_ARCH ${arch})
endmacro()

macro(detect_target_arch)
  check_symbol_exists(__arm__ "" __ARM)
  check_symbol_exists(__aarch64__ "" __AARCH64)
  check_symbol_exists(__x86_64__ "" __X86_64)
  check_symbol_exists(__i686__ "" __I686)
  check_symbol_exists(__i386__ "" __I386)
  check_symbol_exists(__mips__ "" __MIPS)
  check_symbol_exists(__mips64__ "" __MIPS64)
  check_symbol_exists(__wasm32__ "" __WEBASSEMBLY32)
  check_symbol_exists(__wasm64__ "" __WEBASSEMBLY64)
  if(__ARM)
    add_default_target_arch(arm)
  elseif(__AARCH64)
    add_default_target_arch(aarch64)
  elseif(__X86_64)
    add_default_target_arch(x86_64)
  elseif(__I686)
    add_default_target_arch(i686)
  elseif(__I386)
    add_default_target_arch(i386)
  elseif(__MIPS64) # must be checked before __MIPS
    add_default_target_arch(mips64)
  elseif(__MIPS)
    add_default_target_arch(mips)
  elseif(__WEBASSEMBLY32)
    add_default_target_arch(wasm32)
  elseif(__WEBASSEMBLY64)
    add_default_target_arch(wasm64)
  endif()
endmacro()

# Detect whether the current target platform is 32-bit or 64-bit, and setup
# the correct commandline flags needed to attempt to target 32-bit and 64-bit.
if (NOT CMAKE_SIZEOF_VOID_P EQUAL 4 AND
    NOT CMAKE_SIZEOF_VOID_P EQUAL 8)
  message(FATAL_ERROR "Please use architecture with 4 or 8 byte pointers.")
endif()

# Generate the COMPILER_RT_SUPPORTED_ARCH list.
if(ANDROID)
  # Examine compiler output to determine target architecture.
  detect_target_arch()
  set(COMPILER_RT_OS_SUFFIX "-android")
elseif(NOT APPLE) # Supported archs for Apple platforms are generated later
  if("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "i[2-6]86|x86|amd64")
    if(NOT MSVC)
      test_target_arch(x86_64 "" "-m64")
      # FIXME: We build runtimes for both i686 and i386, as "clang -m32" may
      # target different variant than "$CMAKE_C_COMPILER -m32". This part should
      # be gone after we resolve PR14109.
      test_target_arch(i686 __i686__ "-m32")
      test_target_arch(i386 __i386__ "-m32")
    else()
      if (CMAKE_SIZEOF_VOID_P EQUAL 4)
        test_target_arch(i386 "" "")
      else()
        test_target_arch(x86_64 "" "")
      endif()
    endif()
  elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "powerpc")
    TEST_BIG_ENDIAN(HOST_IS_BIG_ENDIAN)
    if(HOST_IS_BIG_ENDIAN)
      test_target_arch(powerpc64 "" "-m64")
    else()
      test_target_arch(powerpc64le "" "-m64")
    endif()
  elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "mipsel|mips64el")
    # Gcc doesn't accept -m32/-m64 so we do the next best thing and use
    # -mips32r2/-mips64r2. We don't use -mips1/-mips3 because we want to match
    # clang's default CPU's. In the 64-bit case, we must also specify the ABI
    # since the default ABI differs between gcc and clang.
    # FIXME: Ideally, we would build the N32 library too.
    test_target_arch(mipsel "" "-mips32r2" "--target=mipsel-linux-gnu")
    test_target_arch(mips64el "" "-mips64r2" "--target=mips64el-linux-gnu" "-mabi=n64")
  elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "mips")
    test_target_arch(mips "" "-mips32r2" "--target=mips-linux-gnu")
    test_target_arch(mips64 "" "-mips64r2" "--target=mips64-linux-gnu" "-mabi=n64")
  elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "arm")
    test_target_arch(arm "" "-march=armv7-a" "-mfloat-abi=soft")
    test_target_arch(armhf "" "-march=armv7-a" "-mfloat-abi=hard")
  elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "aarch32")
    test_target_arch(aarch32 "" "-march=armv8-a")
  elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "aarch64")
    test_target_arch(aarch64 "" "-march=armv8-a")
  elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "wasm32")
    test_target_arch(wasm32 "" "--target=wasm32-unknown-unknown")
  elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "wasm64")
    test_target_arch(wasm64 "" "--target=wasm64-unknown-unknown")
  endif()
  set(COMPILER_RT_OS_SUFFIX "")
endif()

# Takes ${ARGN} and puts only supported architectures in @out_var list.
function(filter_available_targets out_var)
  set(archs ${${out_var}})
  foreach(arch ${ARGN})
    list(FIND COMPILER_RT_SUPPORTED_ARCH ${arch} ARCH_INDEX)
    if(NOT (ARCH_INDEX EQUAL -1) AND CAN_TARGET_${arch})
      list(APPEND archs ${arch})
    endif()
  endforeach()
  set(${out_var} ${archs} PARENT_SCOPE)
endfunction()

# Returns a list of architecture specific target cflags in @out_var list.
function(get_target_flags_for_arch arch out_var)
  list(FIND COMPILER_RT_SUPPORTED_ARCH ${arch} ARCH_INDEX)
  if(ARCH_INDEX EQUAL -1)
    message(FATAL_ERROR "Unsupported architecture: ${arch}")
  else()
    if (NOT APPLE)
      set(${out_var} ${TARGET_${arch}_CFLAGS} PARENT_SCOPE)
    else()
      # This is only called in constructing cflags for tests executing on the
      # host. This will need to all be cleaned up to support building tests
      # for cross-targeted hardware (i.e. iOS).
      set(${out_var} -arch ${arch} PARENT_SCOPE)
    endif()
  endif()
endfunction()

set(ARM64 aarch64)
set(ARM32 arm armhf)
set(X86 i386 i686)
set(X86_64 x86_64)
set(MIPS32 mips mipsel)
set(MIPS64 mips64 mips64el)
set(PPC64 powerpc64 powerpc64le)
set(WASM32 wasm32)
set(WASM64 wasm64)

if(APPLE)
  set(ARM64 arm64)
  set(ARM32 armv7 armv7s)
  set(X86_64 x86_64 x86_64h)
endif()

set(ALL_BUILTIN_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM32} ${ARM64}
    ${MIPS32} ${MIPS64} ${WASM32} ${WASM64})
set(ALL_SANITIZER_COMMON_SUPPORTED_ARCH ${X86} ${X86_64} ${PPC64}
    ${ARM32} ${ARM64} ${MIPS32} ${MIPS64})
set(ALL_ASAN_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM32} ${ARM64}
    ${MIPS32} ${MIPS64} ${PPC64})
set(ALL_DFSAN_SUPPORTED_ARCH ${X86_64} ${MIPS64} ${ARM64})
set(ALL_LSAN_SUPPORTED_ARCH ${X86_64} ${MIPS64} ${ARM64})
set(ALL_MSAN_SUPPORTED_ARCH ${X86_64} ${MIPS64} ${ARM64})
set(ALL_PROFILE_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM32} ${ARM64} ${PPC64}
    ${MIPS32} ${MIPS64})
set(ALL_TSAN_SUPPORTED_ARCH ${X86_64} ${MIPS64} ${ARM64} ${PPC64})
set(ALL_UBSAN_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM32} ${ARM64}
    ${MIPS32} ${MIPS64} ${PPC64})
set(ALL_SAFESTACK_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM64})
set(ALL_CFI_SUPPORTED_ARCH ${X86} ${X86_64})

if(APPLE)
  include(CompilerRTDarwinUtils)

  # On Darwin if /usr/include doesn't exist, the user probably has Xcode but not
  # the command line tools. If this is the case, we need to find the OS X
  # sysroot to pass to clang.
  if(NOT EXISTS /usr/include)
    execute_process(COMMAND xcodebuild -version -sdk macosx Path
       OUTPUT_VARIABLE OSX_SYSROOT
       ERROR_QUIET
       OUTPUT_STRIP_TRAILING_WHITESPACE)
    set(OSX_SYSROOT_FLAG "-isysroot${OSX_SYSROOT}")
  endif()

  option(COMPILER_RT_ENABLE_IOS "Enable building for iOS - Experimental" Off)
  option(COMPILER_RT_ENABLE_WATCHOS "Enable building for watchOS - Experimental" Off)
  option(COMPILER_RT_ENABLE_TVOS "Enable building for tvOS - Experimental" Off)

  find_darwin_sdk_dir(DARWIN_osx_SYSROOT macosx)
  find_darwin_sdk_dir(DARWIN_iossim_SYSROOT iphonesimulator)
  find_darwin_sdk_dir(DARWIN_ios_SYSROOT iphoneos)
  find_darwin_sdk_dir(DARWIN_watchossim_SYSROOT watchsimulator)
  find_darwin_sdk_dir(DARWIN_watchos_SYSROOT watchos)
  find_darwin_sdk_dir(DARWIN_tvossim_SYSROOT appletvsimulator)
  find_darwin_sdk_dir(DARWIN_tvos_SYSROOT appletvos)

  if(COMPILER_RT_ENABLE_IOS)
    list(APPEND DARWIN_EMBEDDED_PLATFORMS ios)
    set(DARWIN_ios_MIN_VER_FLAG -miphoneos-version-min)
    set(DARWIN_ios_SANITIZER_MIN_VER_FLAG
      ${DARWIN_ios_MIN_VER_FLAG}=7.0)
    set(DARWIN_ios_BUILTIN_MIN_VER 6.0)
    set(DARWIN_ios_BUILTIN_MIN_VER_FLAG
      ${DARWIN_ios_MIN_VER_FLAG}=${DARWIN_ios_BUILTIN_MIN_VER})
  endif()
  if(COMPILER_RT_ENABLE_WATCHOS)
    list(APPEND DARWIN_EMBEDDED_PLATFORMS watchos)
    set(DARWIN_watchos_MIN_VER_FLAG -mwatchos-version-min)
    set(DARWIN_watchos_SANITIZER_MIN_VER_FLAG
      ${DARWIN_watchos_MIN_VER_FLAG}=2.0)
    set(DARWIN_watchos_BUILTIN_MIN_VER 2.0)
    set(DARWIN_watchos_BUILTIN_MIN_VER_FLAG
      ${DARWIN_watchos_MIN_VER_FLAG}=${DARWIN_watchos_BUILTIN_MIN_VER})
  endif()
  if(COMPILER_RT_ENABLE_TVOS)
    list(APPEND DARWIN_EMBEDDED_PLATFORMS tvos)
    set(DARWIN_tvos_MIN_VER_FLAG -mtvos-version-min)
    set(DARWIN_tvos_SANITIZER_MIN_VER_FLAG
      ${DARWIN_tvos_MIN_VER_FLAG}=9.0)
    set(DARWIN_tvos_BUILTIN_MIN_VER 9.0)
    set(DARWIN_tvos_BUILTIN_MIN_VER_FLAG
      ${DARWIN_tvos_MIN_VER_FLAG}=${DARWIN_tvos_BUILTIN_MIN_VER})
  endif()

  # Note: In order to target x86_64h on OS X the minimum deployment target must
  # be 10.8 or higher.
  set(SANITIZER_COMMON_SUPPORTED_OS osx)
  set(BUILTIN_SUPPORTED_OS osx)
  set(PROFILE_SUPPORTED_OS osx)
  set(TSAN_SUPPORTED_OS osx)
  if(NOT SANITIZER_MIN_OSX_VERSION)
    string(REGEX MATCH "-mmacosx-version-min=([.0-9]+)"
           MACOSX_VERSION_MIN_FLAG "${CMAKE_CXX_FLAGS}")
    if(MACOSX_VERSION_MIN_FLAG)
      set(SANITIZER_MIN_OSX_VERSION "${CMAKE_MATCH_1}")
    elseif(CMAKE_OSX_DEPLOYMENT_TARGET)
      set(SANITIZER_MIN_OSX_VERSION ${CMAKE_OSX_DEPLOYMENT_TARGET})
    else()
      set(SANITIZER_MIN_OSX_VERSION 10.9)
    endif()
    if(SANITIZER_MIN_OSX_VERSION VERSION_LESS "10.7")
      message(FATAL_ERROR "Too old OS X version: ${SANITIZER_MIN_OSX_VERSION}")
    endif()
  endif()

  # We're setting the flag manually for each target OS
  set(CMAKE_OSX_DEPLOYMENT_TARGET "")
  
  set(DARWIN_COMMON_CFLAGS -stdlib=libc++)
  set(DARWIN_COMMON_LINKFLAGS
    -stdlib=libc++
    -lc++
    -lc++abi)
  
  check_linker_flag("-fapplication-extension" COMPILER_RT_HAS_APP_EXTENSION)
  if(COMPILER_RT_HAS_APP_EXTENSION)
    list(APPEND DARWIN_COMMON_LINKFLAGS "-fapplication-extension")
  endif()

  set(DARWIN_osx_CFLAGS
    ${DARWIN_COMMON_CFLAGS}
    -mmacosx-version-min=${SANITIZER_MIN_OSX_VERSION})
  set(DARWIN_osx_LINKFLAGS
    ${DARWIN_COMMON_LINKFLAGS}
    -mmacosx-version-min=${SANITIZER_MIN_OSX_VERSION})
  set(DARWIN_osx_BUILTIN_MIN_VER 10.5)
  set(DARWIN_osx_BUILTIN_MIN_VER_FLAG
      -mmacosx-version-min=${DARWIN_osx_BUILTIN_MIN_VER})

  if(DARWIN_osx_SYSROOT)
    list(APPEND DARWIN_osx_CFLAGS -isysroot ${DARWIN_osx_SYSROOT})
    list(APPEND DARWIN_osx_LINKFLAGS -isysroot ${DARWIN_osx_SYSROOT})
  endif()

  # Figure out which arches to use for each OS
  darwin_get_toolchain_supported_archs(toolchain_arches)
  message(STATUS "Toolchain supported arches: ${toolchain_arches}")
  
  if(NOT MACOSX_VERSION_MIN_FLAG)
    darwin_test_archs(osx
      DARWIN_osx_ARCHS
      ${toolchain_arches})
    message(STATUS "OSX supported arches: ${DARWIN_osx_ARCHS}")
    foreach(arch ${DARWIN_osx_ARCHS})
      list(APPEND COMPILER_RT_SUPPORTED_ARCH ${arch})
      set(CAN_TARGET_${arch} 1)
    endforeach()

    # Need to build a 10.4 compatible libclang_rt
    set(DARWIN_10.4_SYSROOT ${DARWIN_osx_SYSROOT})
    set(DARWIN_10.4_BUILTIN_MIN_VER 10.4)
    set(DARWIN_10.4_BUILTIN_MIN_VER_FLAG
        -mmacosx-version-min=${DARWIN_10.4_BUILTIN_MIN_VER})
    set(DARWIN_10.4_SKIP_CC_KEXT On)
    darwin_test_archs(10.4
      DARWIN_10.4_ARCHS
      ${toolchain_arches})
    message(STATUS "OSX 10.4 supported arches: ${DARWIN_10.4_ARCHS}")
    if(DARWIN_10.4_ARCHS)
      # don't include the Haswell slice in the 10.4 compatibility library
      list(REMOVE_ITEM DARWIN_10.4_ARCHS x86_64h)
      list(APPEND BUILTIN_SUPPORTED_OS 10.4)
    endif()

    foreach(platform ${DARWIN_EMBEDDED_PLATFORMS})
      if(DARWIN_${platform}sim_SYSROOT)
        set(DARWIN_${platform}sim_CFLAGS
          ${DARWIN_COMMON_CFLAGS}
          ${DARWIN_${platform}_SANITIZER_MIN_VER_FLAG}
          -isysroot ${DARWIN_iossim_SYSROOT})
        set(DARWIN_${platform}sim_LINKFLAGS
          ${DARWIN_COMMON_LINKFLAGS}
          ${DARWIN_${platform}_SANITIZER_MIN_VER_FLAG}
          -isysroot ${DARWIN_${platform}sim_SYSROOT})
        set(DARWIN_${platform}sim_BUILTIN_MIN_VER
          ${DARWIN_${platform}_BUILTIN_MIN_VER})
        set(DARWIN_${platform}sim_BUILTIN_MIN_VER_FLAG
          ${DARWIN_${platform}_BUILTIN_MIN_VER_FLAG})

        set(DARWIN_${platform}sim_SKIP_CC_KEXT On)
        darwin_test_archs(${platform}sim
          DARWIN_${platform}sim_ARCHS
          ${toolchain_arches})
        message(STATUS "${platform} Simulator supported arches: ${DARWIN_${platform}sim_ARCHS}")
        if(DARWIN_iossim_ARCHS)
          list(APPEND SANITIZER_COMMON_SUPPORTED_OS ${platform}sim)
          list(APPEND BUILTIN_SUPPORTED_OS ${platform}sim)
          list(APPEND PROFILE_SUPPORTED_OS ${platform}sim)
        endif()
        foreach(arch ${DARWIN_${platform}sim_ARCHS})
          list(APPEND COMPILER_RT_SUPPORTED_ARCH ${arch})
          set(CAN_TARGET_${arch} 1)
        endforeach()
      endif()

      if(DARWIN_${platform}_SYSROOT)
        set(DARWIN_${platform}_CFLAGS
          ${DARWIN_COMMON_CFLAGS}
          ${DARWIN_${platform}_SANITIZER_MIN_VER_FLAG}
          -isysroot ${DARWIN_${platform}_SYSROOT})
        set(DARWIN_${platform}_LINKFLAGS
          ${DARWIN_COMMON_LINKFLAGS}
          ${DARWIN_${platform}_SANITIZER_MIN_VER_FLAG}
          -isysroot ${DARWIN_${platform}_SYSROOT})

        darwin_test_archs(${platform}
          DARWIN_${platform}_ARCHS
          ${toolchain_arches})
        message(STATUS "${platform} supported arches: ${DARWIN_${platform}_ARCHS}")
        if(DARWIN_${platform}_ARCHS)
          list(APPEND SANITIZER_COMMON_SUPPORTED_OS ${platform})
          list(APPEND BUILTIN_SUPPORTED_OS ${platform})
          list(APPEND PROFILE_SUPPORTED_OS ${platform})
        endif()
        foreach(arch ${DARWIN_${platform}_ARCHS})
          list(APPEND COMPILER_RT_SUPPORTED_ARCH ${arch})
          set(CAN_TARGET_${arch} 1)
        endforeach()
      endif()
    endforeach()
  endif()

  # for list_union
  include(CompilerRTUtils)

  list_union(BUILTIN_SUPPORTED_ARCH ALL_BUILTIN_SUPPORTED_ARCH toolchain_arches)

  list_union(SANITIZER_COMMON_SUPPORTED_ARCH
    ALL_SANITIZER_COMMON_SUPPORTED_ARCH
    COMPILER_RT_SUPPORTED_ARCH
    )
  set(LSAN_COMMON_SUPPORTED_ARCH ${SANITIZER_COMMON_SUPPORTED_ARCH})
  set(UBSAN_COMMON_SUPPORTED_ARCH ${SANITIZER_COMMON_SUPPORTED_ARCH})
  list_union(ASAN_SUPPORTED_ARCH
    ALL_ASAN_SUPPORTED_ARCH
    SANITIZER_COMMON_SUPPORTED_ARCH)
  list_union(DFSAN_SUPPORTED_ARCH
    ALL_DFSAN_SUPPORTED_ARCH
    SANITIZER_COMMON_SUPPORTED_ARCH)
  list_union(LSAN_SUPPORTED_ARCH
    ALL_LSAN_SUPPORTED_ARCH
    SANITIZER_COMMON_SUPPORTED_ARCH)
  list_union(MSAN_SUPPORTED_ARCH
    ALL_MSAN_SUPPORTED_ARCH
    SANITIZER_COMMON_SUPPORTED_ARCH)
  list_union(PROFILE_SUPPORTED_ARCH
    ALL_PROFILE_SUPPORTED_ARCH
    SANITIZER_COMMON_SUPPORTED_ARCH)
  list_union(TSAN_SUPPORTED_ARCH
    ALL_TSAN_SUPPORTED_ARCH
    SANITIZER_COMMON_SUPPORTED_ARCH)
  list_union(UBSAN_SUPPORTED_ARCH
    ALL_UBSAN_SUPPORTED_ARCH
    SANITIZER_COMMON_SUPPORTED_ARCH)
  list_union(SAFESTACK_SUPPORTED_ARCH
    ALL_SAFESTACK_SUPPORTED_ARCH
    SANITIZER_COMMON_SUPPORTED_ARCH)
  list_union(CFI_SUPPORTED_ARCH
    ALL_CFI_SUPPORTED_ARCH
    SANITIZER_COMMON_SUPPORTED_ARCH)
else()
  # Architectures supported by compiler-rt libraries.
  filter_available_targets(BUILTIN_SUPPORTED_ARCH
    ${ALL_BUILTIN_SUPPORTED_ARCH})
  filter_available_targets(SANITIZER_COMMON_SUPPORTED_ARCH
    ${ALL_SANITIZER_COMMON_SUPPORTED_ARCH})
  # LSan and UBSan common files should be available on all architectures
  # supported by other sanitizers (even if they build into dummy object files).
  filter_available_targets(LSAN_COMMON_SUPPORTED_ARCH
    ${SANITIZER_COMMON_SUPPORTED_ARCH})
  filter_available_targets(UBSAN_COMMON_SUPPORTED_ARCH
    ${SANITIZER_COMMON_SUPPORTED_ARCH})
  filter_available_targets(ASAN_SUPPORTED_ARCH ${ALL_ASAN_SUPPORTED_ARCH})
  filter_available_targets(DFSAN_SUPPORTED_ARCH ${ALL_DFSAN_SUPPORTED_ARCH})
  filter_available_targets(LSAN_SUPPORTED_ARCH ${ALL_LSAN_SUPPORTED_ARCH})
  filter_available_targets(MSAN_SUPPORTED_ARCH ${ALL_MSAN_SUPPORTED_ARCH})
  filter_available_targets(PROFILE_SUPPORTED_ARCH ${ALL_PROFILE_SUPPORTED_ARCH})
  filter_available_targets(TSAN_SUPPORTED_ARCH ${ALL_TSAN_SUPPORTED_ARCH})
  filter_available_targets(UBSAN_SUPPORTED_ARCH ${ALL_UBSAN_SUPPORTED_ARCH})
  filter_available_targets(SAFESTACK_SUPPORTED_ARCH
    ${ALL_SAFESTACK_SUPPORTED_ARCH})
  filter_available_targets(CFI_SUPPORTED_ARCH ${ALL_CFI_SUPPORTED_ARCH})
endif()

if (MSVC)
  # See if the DIA SDK is available and usable.
  set(MSVC_DIA_SDK_DIR "$ENV{VSINSTALLDIR}DIA SDK")
  if (IS_DIRECTORY ${MSVC_DIA_SDK_DIR})
    set(CAN_SYMBOLIZE 1)
  else()
    set(CAN_SYMBOLIZE 0)
  endif()
else()
  set(CAN_SYMBOLIZE 1)
endif()

message(STATUS "Compiler-RT supported architectures: ${COMPILER_RT_SUPPORTED_ARCH}")

if(ANDROID)
  set(OS_NAME "Android")
else()
  set(OS_NAME "${CMAKE_SYSTEM_NAME}")
endif()

if (SANITIZER_COMMON_SUPPORTED_ARCH AND NOT LLVM_USE_SANITIZER AND
    (OS_NAME MATCHES "Android|Darwin|Linux|FreeBSD" OR
    (OS_NAME MATCHES "Windows" AND MSVC)))
  set(COMPILER_RT_HAS_SANITIZER_COMMON TRUE)
else()
  set(COMPILER_RT_HAS_SANITIZER_COMMON FALSE)
endif()

if (COMPILER_RT_HAS_SANITIZER_COMMON AND
    (NOT OS_NAME MATCHES "Windows" OR CMAKE_SIZEOF_VOID_P EQUAL 4))
  set(COMPILER_RT_HAS_INTERCEPTION TRUE)
else()
  set(COMPILER_RT_HAS_INTERCEPTION FALSE)
endif()

if (COMPILER_RT_HAS_SANITIZER_COMMON AND ASAN_SUPPORTED_ARCH AND
    (NOT OS_NAME MATCHES "Windows" OR CMAKE_SIZEOF_VOID_P EQUAL 4))
  set(COMPILER_RT_HAS_ASAN TRUE)
else()
  set(COMPILER_RT_HAS_ASAN FALSE)
endif()

if (OS_NAME MATCHES "Linux|FreeBSD|Windows")
  set(COMPILER_RT_ASAN_HAS_STATIC_RUNTIME TRUE)
else()
  set(COMPILER_RT_ASAN_HAS_STATIC_RUNTIME FALSE)
endif()

# TODO: Add builtins support.

if (COMPILER_RT_HAS_SANITIZER_COMMON AND DFSAN_SUPPORTED_ARCH AND
    OS_NAME MATCHES "Linux")
  set(COMPILER_RT_HAS_DFSAN TRUE)
else()
  set(COMPILER_RT_HAS_DFSAN FALSE)
endif()

if (COMPILER_RT_HAS_SANITIZER_COMMON AND LSAN_SUPPORTED_ARCH AND
    OS_NAME MATCHES "Linux|FreeBSD")
  set(COMPILER_RT_HAS_LSAN TRUE)
else()
  set(COMPILER_RT_HAS_LSAN FALSE)
endif()

if (COMPILER_RT_HAS_SANITIZER_COMMON AND MSAN_SUPPORTED_ARCH AND
    OS_NAME MATCHES "Linux")
  set(COMPILER_RT_HAS_MSAN TRUE)
else()
  set(COMPILER_RT_HAS_MSAN FALSE)
endif()

if (PROFILE_SUPPORTED_ARCH AND
    OS_NAME MATCHES "Darwin|Linux|FreeBSD|Windows")
  set(COMPILER_RT_HAS_PROFILE TRUE)
else()
  set(COMPILER_RT_HAS_PROFILE FALSE)
endif()

if (COMPILER_RT_HAS_SANITIZER_COMMON AND TSAN_SUPPORTED_ARCH AND
    OS_NAME MATCHES "Darwin|Linux|FreeBSD")
  set(COMPILER_RT_HAS_TSAN TRUE)
else()
  set(COMPILER_RT_HAS_TSAN FALSE)
endif()

if (COMPILER_RT_HAS_SANITIZER_COMMON AND UBSAN_SUPPORTED_ARCH AND
    OS_NAME MATCHES "Darwin|Linux|FreeBSD|Windows")
  set(COMPILER_RT_HAS_UBSAN TRUE)
else()
  set(COMPILER_RT_HAS_UBSAN FALSE)
endif()

if (COMPILER_RT_HAS_SANITIZER_COMMON AND SAFESTACK_SUPPORTED_ARCH AND
    OS_NAME MATCHES "Darwin|Linux|FreeBSD")
  set(COMPILER_RT_HAS_SAFESTACK TRUE)
else()
  set(COMPILER_RT_HAS_SAFESTACK FALSE)
endif()

if (COMPILER_RT_HAS_SANITIZER_COMMON AND CFI_SUPPORTED_ARCH AND
    OS_NAME MATCHES "Linux")
  set(COMPILER_RT_HAS_CFI TRUE)
else()
  set(COMPILER_RT_HAS_CFI FALSE)
endif()