1# See www/CMake.html for instructions on how to build libcxx with CMake. 2 3#=============================================================================== 4# Setup Project 5#=============================================================================== 6cmake_minimum_required(VERSION 3.4.3) 7 8if(POLICY CMP0042) 9 cmake_policy(SET CMP0042 NEW) # Set MACOSX_RPATH=YES by default 10endif() 11if(POLICY CMP0022) 12 cmake_policy(SET CMP0022 NEW) # Required when interacting with LLVM and Clang 13endif() 14if(POLICY CMP0068) 15 cmake_policy(SET CMP0068 NEW) 16 set(CMAKE_BUILD_WITH_INSTALL_NAME_DIR ON) 17endif() 18 19# Add path for custom modules 20set(CMAKE_MODULE_PATH 21 "${CMAKE_CURRENT_SOURCE_DIR}/cmake" 22 "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules" 23 ${CMAKE_MODULE_PATH} 24 ) 25 26if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR) 27 project(libcxx CXX C) 28 29 set(PACKAGE_NAME libcxx) 30 set(PACKAGE_VERSION 8.0.0svn) 31 set(PACKAGE_STRING "${PACKAGE_NAME} ${PACKAGE_VERSION}") 32 set(PACKAGE_BUGREPORT "llvm-bugs@lists.llvm.org") 33 34 # Find the LLVM sources and simulate LLVM CMake options. 35 include(HandleOutOfTreeLLVM) 36endif() 37 38if (LIBCXX_STANDALONE_BUILD) 39 include(FindPythonInterp) 40 if( NOT PYTHONINTERP_FOUND ) 41 message(WARNING "Failed to find python interpreter. " 42 "The libc++ test suite will be disabled.") 43 set(LLVM_INCLUDE_TESTS OFF) 44 endif() 45endif() 46 47# Require out of source build. 48include(MacroEnsureOutOfSourceBuild) 49MACRO_ENSURE_OUT_OF_SOURCE_BUILD( 50 "${PROJECT_NAME} requires an out of source build. Please create a separate 51 build directory and run 'cmake /path/to/${PROJECT_NAME} [options]' there." 52 ) 53if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" AND "${CMAKE_CXX_SIMULATE_ID}" STREQUAL "MSVC") 54 message(STATUS "Configuring for clang-cl") 55 set(LIBCXX_TARGETING_CLANG_CL ON) 56endif() 57 58if (MSVC) 59 set(LIBCXX_TARGETING_MSVC ON) 60 message(STATUS "Configuring for MSVC") 61else() 62 set(LIBCXX_TARGETING_MSVC OFF) 63endif() 64 65#=============================================================================== 66# Setup CMake Options 67#=============================================================================== 68include(CMakeDependentOption) 69include(HandleCompilerRT) 70 71# Basic options --------------------------------------------------------------- 72option(LIBCXX_ENABLE_ASSERTIONS "Enable assertions independent of build mode." OFF) 73option(LIBCXX_ENABLE_SHARED "Build libc++ as a shared library." ON) 74option(LIBCXX_ENABLE_STATIC "Build libc++ as a static library." ON) 75option(LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY "Build libc++experimental.a" ON) 76set(ENABLE_FILESYSTEM_DEFAULT ${LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY}) 77if (WIN32) 78 set(ENABLE_FILESYSTEM_DEFAULT OFF) 79endif() 80option(LIBCXX_ENABLE_FILESYSTEM "Build filesystem as part of libc++fs.a" 81 ${ENABLE_FILESYSTEM_DEFAULT}) 82option(LIBCXX_INCLUDE_TESTS "Build the libc++ tests." ${LLVM_INCLUDE_TESTS}) 83 84# Benchmark options ----------------------------------------------------------- 85option(LIBCXX_INCLUDE_BENCHMARKS "Build the libc++ benchmarks and their dependencies" ON) 86 87set(LIBCXX_BENCHMARK_TEST_ARGS_DEFAULT --benchmark_min_time=0.01) 88set(LIBCXX_BENCHMARK_TEST_ARGS "${LIBCXX_BENCHMARK_TEST_ARGS_DEFAULT}" CACHE STRING 89 "Arguments to pass when running the benchmarks using check-cxx-benchmarks") 90 91set(LIBCXX_BENCHMARK_NATIVE_STDLIB "" CACHE STRING 92 "Build the benchmarks against the specified native STL. 93 The value must be one of libc++/libstdc++") 94set(LIBCXX_BENCHMARK_NATIVE_GCC_TOOLCHAIN "" CACHE STRING 95 "Use alternate GCC toolchain when building the native benchmarks") 96 97if (LIBCXX_BENCHMARK_NATIVE_STDLIB) 98 if (NOT (LIBCXX_BENCHMARK_NATIVE_STDLIB STREQUAL "libc++" 99 OR LIBCXX_BENCHMARK_NATIVE_STDLIB STREQUAL "libstdc++")) 100 message(FATAL_ERROR "Invalid value for LIBCXX_BENCHMARK_NATIVE_STDLIB: " 101 "'${LIBCXX_BENCHMARK_NATIVE_STDLIB}'") 102 endif() 103endif() 104 105option(LIBCXX_INCLUDE_DOCS "Build the libc++ documentation." ${LLVM_INCLUDE_DOCS}) 106set(LIBCXX_LIBDIR_SUFFIX "${LLVM_LIBDIR_SUFFIX}" CACHE STRING 107 "Define suffix of library directory name (32/64)") 108option(LIBCXX_INSTALL_HEADERS "Install the libc++ headers." ON) 109option(LIBCXX_INSTALL_LIBRARY "Install the libc++ library." ON) 110cmake_dependent_option(LIBCXX_INSTALL_STATIC_LIBRARY 111 "Install the static libc++ library." ON 112 "LIBCXX_ENABLE_STATIC;LIBCXX_INSTALL_LIBRARY" OFF) 113cmake_dependent_option(LIBCXX_INSTALL_SHARED_LIBRARY 114 "Install the shared libc++ library." ON 115 "LIBCXX_ENABLE_SHARED;LIBCXX_INSTALL_LIBRARY" OFF) 116option(LIBCXX_INSTALL_SUPPORT_HEADERS "Install libc++ support headers." ON) 117cmake_dependent_option(LIBCXX_INSTALL_EXPERIMENTAL_LIBRARY 118 "Install libc++experimental.a" ON 119 "LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY;LIBCXX_INSTALL_LIBRARY" OFF) 120cmake_dependent_option(LIBCXX_INSTALL_FILESYSTEM_LIBRARY 121 "Install libc++fs.a" ON 122 "LIBCXX_ENABLE_FILESYSTEM;LIBCXX_INSTALL_LIBRARY" OFF) 123 124set(LIBCXX_ABI_VERSION "1" CACHE STRING "ABI version of libc++. Can be either 1 or 2, where 2 is currently not stable. Defaults to 1.") 125set(LIBCXX_ABI_NAMESPACE "" CACHE STRING "The inline ABI namespace used by libc++. It defaults to __n where `n` is the current ABI version.") 126option(LIBCXX_ABI_UNSTABLE "Unstable ABI of libc++." OFF) 127option(LIBCXX_ABI_FORCE_ITANIUM "Ignore auto-detection and force use of the Itanium ABI.") 128option(LIBCXX_ABI_FORCE_MICROSOFT "Ignore auto-detection and force use of the Microsoft ABI.") 129option(LIBCXX_HIDE_FROM_ABI_PER_TU_BY_DEFAULT "Enable per TU ABI insulation by default. To be used by vendors." OFF) 130set(LIBCXX_ABI_DEFINES "" CACHE STRING "A semicolon separated list of ABI macros to define in the site config header.") 131option(LIBCXX_USE_COMPILER_RT "Use compiler-rt instead of libgcc" OFF) 132 133if (NOT LIBCXX_ENABLE_SHARED AND NOT LIBCXX_ENABLE_STATIC) 134 message(FATAL_ERROR "libc++ must be built as either a shared or static library.") 135endif() 136 137# ABI Library options --------------------------------------------------------- 138set(LIBCXX_CXX_ABI "default" CACHE STRING 139 "Specify C++ ABI library to use.") 140set(CXXABIS none default libcxxabi libcxxrt libstdc++ libsupc++ vcruntime) 141set_property(CACHE LIBCXX_CXX_ABI PROPERTY STRINGS ;${CXXABIS}) 142 143# Setup the default options if LIBCXX_CXX_ABI is not specified. 144if (LIBCXX_CXX_ABI STREQUAL "default") 145 find_path( 146 LIBCXX_LIBCXXABI_INCLUDES_INTERNAL 147 cxxabi.h 148 PATHS ${LLVM_MAIN_SRC_DIR}/projects/libcxxabi/include 149 ${LLVM_MAIN_SRC_DIR}/runtimes/libcxxabi/include 150 ${LLVM_MAIN_SRC_DIR}/../libcxxabi/include 151 NO_DEFAULT_PATH 152 NO_CMAKE_FIND_ROOT_PATH 153 ) 154 if (LIBCXX_TARGETING_MSVC) 155 # FIXME: Figure out how to configure the ABI library on Windows. 156 set(LIBCXX_CXX_ABI_LIBNAME "vcruntime") 157 elseif ((NOT LIBCXX_STANDALONE_BUILD OR HAVE_LIBCXXABI) AND 158 IS_DIRECTORY "${LIBCXX_LIBCXXABI_INCLUDES_INTERNAL}") 159 set(LIBCXX_CXX_ABI_LIBNAME "libcxxabi") 160 set(LIBCXX_CXX_ABI_INCLUDE_PATHS "${LIBCXX_LIBCXXABI_INCLUDES_INTERNAL}") 161 set(LIBCXX_CXX_ABI_INTREE 1) 162 elseif (APPLE) 163 set(LIBCXX_CXX_ABI_LIBNAME "libcxxabi") 164 set(LIBCXX_CXX_ABI_SYSTEM 1) 165 elseif (${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD") 166 set(LIBCXX_CXX_ABI_LIBNAME "libcxxrt") 167 set(LIBCXX_CXX_ABI_INCLUDE_PATHS "/usr/include/c++/v1") 168 else() 169 set(LIBCXX_CXX_ABI_LIBNAME "default") 170 endif() 171else() 172 set(LIBCXX_CXX_ABI_LIBNAME "${LIBCXX_CXX_ABI}") 173endif() 174 175# Use a static copy of the ABI library when linking libc++. This option 176# cannot be used with LIBCXX_ENABLE_ABI_LINKER_SCRIPT. 177option(LIBCXX_ENABLE_STATIC_ABI_LIBRARY "Statically link the ABI library" OFF) 178 179cmake_dependent_option(LIBCXX_STATICALLY_LINK_ABI_IN_STATIC_LIBRARY 180 "Statically link the ABI library to static library" ON 181 "LIBCXX_ENABLE_STATIC_ABI_LIBRARY;LIBCXX_ENABLE_STATIC" OFF) 182 183cmake_dependent_option(LIBCXX_STATICALLY_LINK_ABI_IN_SHARED_LIBRARY 184 "Statically link the ABI library to shared library" ON 185 "LIBCXX_ENABLE_STATIC_ABI_LIBRARY;LIBCXX_ENABLE_SHARED" OFF) 186 187# Generate and install a linker script inplace of libc++.so. The linker script 188# will link libc++ to the correct ABI library. This option is on by default 189# on UNIX platforms other than Apple unless 'LIBCXX_ENABLE_STATIC_ABI_LIBRARY' 190# is on. This option is also disabled when the ABI library is not specified 191# or is specified to be "none". 192set(ENABLE_LINKER_SCRIPT_DEFAULT_VALUE OFF) 193if (LLVM_HAVE_LINK_VERSION_SCRIPT AND NOT LIBCXX_STATICALLY_LINK_ABI_IN_SHARED_LIBRARY 194 AND NOT LIBCXX_CXX_ABI_LIBNAME STREQUAL "none" 195 AND NOT LIBCXX_CXX_ABI_LIBNAME STREQUAL "default" 196 AND PYTHONINTERP_FOUND 197 AND LIBCXX_ENABLE_SHARED) 198 set(ENABLE_LINKER_SCRIPT_DEFAULT_VALUE ON) 199endif() 200 201option(LIBCXX_ENABLE_ABI_LINKER_SCRIPT 202 "Use and install a linker script for the given ABI library" 203 ${ENABLE_LINKER_SCRIPT_DEFAULT_VALUE}) 204 205set(ENABLE_NEW_DELETE_DEFAULT ON) 206if (LIBCXXABI_ENABLE_NEW_DELETE_DEFINITIONS) 207# FIXME: This option should default to off. Unfortunatly GCC 4.9 fails to link 208# programs due to undefined references to new/delete in libc++abi so to work 209# around this libc++abi currently defaults LIBCXXABI_ENABLE_NEW_DELETE_DEFINITIONS 210# to ON. Once the GCC bug has been worked around this option should be changed 211# back to OFF. 212 set(ENABLE_NEW_DELETE_DEFAULT ON) 213endif() 214 215option(LIBCXX_ENABLE_NEW_DELETE_DEFINITIONS 216 "Build libc++ with definitions for operator new/delete. This option can 217 be used to disable the definitions when libc++abi is expected to provide 218 them" ${ENABLE_NEW_DELETE_DEFAULT}) 219 220# Build libc++abi with libunwind. We need this option to determine whether to 221# link with libunwind or libgcc_s while running the test cases. 222option(LIBCXXABI_USE_LLVM_UNWINDER "Build and use the LLVM unwinder." OFF) 223option(LIBCXXABI_ENABLE_STATIC_UNWINDER "Statically link the LLVM unwinder." OFF) 224 225# Target options -------------------------------------------------------------- 226option(LIBCXX_BUILD_32_BITS "Build 32 bit libc++." ${LLVM_BUILD_32_BITS}) 227set(LIBCXX_SYSROOT "" CACHE STRING "Use alternate sysroot.") 228set(LIBCXX_GCC_TOOLCHAIN "" CACHE STRING "Use alternate GCC toolchain.") 229 230# Feature options ------------------------------------------------------------- 231option(LIBCXX_ENABLE_EXCEPTIONS "Use exceptions." ON) 232option(LIBCXX_ENABLE_RTTI "Use run time type information." ON) 233option(LIBCXX_ENABLE_GLOBAL_FILESYSTEM_NAMESPACE "Build libc++ with support for the global filesystem namespace." ON) 234option(LIBCXX_ENABLE_STDIN "Build libc++ with support for stdin/std::cin." ON) 235option(LIBCXX_ENABLE_STDOUT "Build libc++ with support for stdout/std::cout." ON) 236option(LIBCXX_ENABLE_THREADS "Build libc++ with support for threads." ON) 237option(LIBCXX_ENABLE_THREAD_UNSAFE_C_FUNCTIONS "Build libc++ with support for thread-unsafe C functions" ON) 238option(LIBCXX_ENABLE_MONOTONIC_CLOCK 239 "Build libc++ with support for a monotonic clock. 240 This option may only be set to OFF when LIBCXX_ENABLE_THREADS=OFF." ON) 241option(LIBCXX_HAS_MUSL_LIBC "Build libc++ with support for the Musl C library" OFF) 242option(LIBCXX_HAS_PTHREAD_API "Ignore auto-detection and force use of pthread API" OFF) 243option(LIBCXX_HAS_WIN32_THREAD_API "Ignore auto-detection and force use of win32 thread API" OFF) 244option(LIBCXX_HAS_EXTERNAL_THREAD_API 245 "Build libc++ with an externalized threading API. 246 This option may only be set to ON when LIBCXX_ENABLE_THREADS=ON." OFF) 247option(LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY 248 "Build libc++ with an externalized threading library. 249 This option may only be set to ON when LIBCXX_ENABLE_THREADS=ON" OFF) 250 251# Misc options ---------------------------------------------------------------- 252# FIXME: Turn -pedantic back ON. It is currently off because it warns 253# about #include_next which is used everywhere. 254option(LIBCXX_ENABLE_PEDANTIC "Compile with pedantic enabled." OFF) 255option(LIBCXX_ENABLE_WERROR "Fail and stop if a warning is triggered." OFF) 256option(LIBCXX_DISABLE_MACRO_CONFLICT_WARNINGS "Disable #warnings about conflicting macros." OFF) 257 258option(LIBCXX_GENERATE_COVERAGE "Enable generating code coverage." OFF) 259set(LIBCXX_COVERAGE_LIBRARY "" CACHE STRING 260 "The Profile-rt library used to build with code coverage") 261 262# Don't allow a user to accidentally overwrite the system libc++ installation on Darwin. 263# If the user specifies -DCMAKE_INSTALL_PREFIX=/usr the install rules for libc++ 264# will not be generated and a warning will be issued. 265option(LIBCXX_OVERRIDE_DARWIN_INSTALL "Enable overwriting darwins libc++ installation." OFF) 266mark_as_advanced(LIBCXX_OVERRIDE_DARWIN_INSTALL) # Don't show this option by default. 267 268if (${CMAKE_SYSTEM_NAME} MATCHES "Darwin" AND NOT LIBCXX_OVERRIDE_DARWIN_INSTALL) 269 if ("${CMAKE_INSTALL_PREFIX}" STREQUAL "/usr") 270 message(WARNING "Disabling libc++ install rules because installation would " 271 "overwrite the systems installation. Configure with " 272 "-DLIBCXX_OVERRIDE_DARWIN_INSTALL=ON to suppress this behaviour.") 273 mark_as_advanced(CLEAR LIBCXX_OVERRIDE_DARWIN_INSTALL) # Show the override option. 274 set(LIBCXX_INSTALL_HEADERS OFF) 275 set(LIBCXX_INSTALL_LIBRARY OFF) 276 endif() 277endif() 278 279set(LIBCXX_CONFIGURE_IDE_DEFAULT OFF) 280if (XCODE OR MSVC_IDE) 281 set(LIBCXX_CONFIGURE_IDE_DEFAULT ON) 282endif() 283option(LIBCXX_CONFIGURE_IDE "Configure libcxx for use within an IDE" 284 ${LIBCXX_CONFIGURE_IDE_DEFAULT}) 285 286option(LIBCXX_HERMETIC_STATIC_LIBRARY 287 "Do not export any symbols from the static library." OFF) 288 289#=============================================================================== 290# Check option configurations 291#=============================================================================== 292 293if (LIBCXX_ENABLE_FILESYSTEM AND NOT LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY) 294 message(FATAL_ERROR 295 "LIBCXX_ENABLE_FILESYSTEM cannot be turned on when LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY=OFF") 296endif() 297 298# Ensure LIBCXX_ENABLE_MONOTONIC_CLOCK is set to ON only when 299# LIBCXX_ENABLE_THREADS is on. 300if(LIBCXX_ENABLE_THREADS AND NOT LIBCXX_ENABLE_MONOTONIC_CLOCK) 301 message(FATAL_ERROR "LIBCXX_ENABLE_MONOTONIC_CLOCK can only be set to OFF" 302 " when LIBCXX_ENABLE_THREADS is also set to OFF.") 303endif() 304 305if(NOT LIBCXX_ENABLE_THREADS) 306 if(LIBCXX_HAS_PTHREAD_API) 307 message(FATAL_ERROR "LIBCXX_HAS_PTHREAD_API can only be set to ON" 308 " when LIBCXX_ENABLE_THREADS is also set to ON.") 309 endif() 310 if(LIBCXX_HAS_EXTERNAL_THREAD_API) 311 message(FATAL_ERROR "LIBCXX_HAS_EXTERNAL_THREAD_API can only be set to ON" 312 " when LIBCXX_ENABLE_THREADS is also set to ON.") 313 endif() 314 if (LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY) 315 message(FATAL_ERROR "LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY can only be set " 316 "to ON when LIBCXX_ENABLE_THREADS is also set to ON.") 317 endif() 318 if (LIBCXX_HAS_WIN32_THREAD_API) 319 message(FATAL_ERROR "LIBCXX_HAS_WIN32_THREAD_API can only be set to ON" 320 " when LIBCXX_ENABLE_THREADS is also set to ON.") 321 endif() 322 323endif() 324 325if (LIBCXX_HAS_EXTERNAL_THREAD_API) 326 if (LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY) 327 message(FATAL_ERROR "The options LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY and " 328 "LIBCXX_HAS_EXTERNAL_THREAD_API cannot both be ON at " 329 "the same time") 330 endif() 331 if (LIBCXX_HAS_PTHREAD_API) 332 message(FATAL_ERROR "The options LIBCXX_HAS_EXTERNAL_THREAD_API" 333 "and LIBCXX_HAS_PTHREAD_API cannot be both" 334 "set to ON at the same time.") 335 endif() 336 if (LIBCXX_HAS_WIN32_THREAD_API) 337 message(FATAL_ERROR "The options LIBCXX_HAS_EXTERNAL_THREAD_API" 338 "and LIBCXX_HAS_WIN32_THREAD_API cannot be both" 339 "set to ON at the same time.") 340 endif() 341endif() 342 343if (LIBCXX_HAS_PTHREAD_API) 344 if (LIBCXX_HAS_WIN32_THREAD_API) 345 message(FATAL_ERROR "The options LIBCXX_HAS_PTHREAD_API" 346 "and LIBCXX_HAS_WIN32_THREAD_API cannot be both" 347 "set to ON at the same time.") 348 endif() 349endif() 350 351# Ensure LLVM_USE_SANITIZER is not specified when LIBCXX_GENERATE_COVERAGE 352# is ON. 353if (LLVM_USE_SANITIZER AND LIBCXX_GENERATE_COVERAGE) 354 message(FATAL_ERROR "LLVM_USE_SANITIZER cannot be used with LIBCXX_GENERATE_COVERAGE") 355endif() 356 357# Set LIBCXX_BUILD_32_BITS to (LIBCXX_BUILD_32_BITS OR LLVM_BUILD_32_BITS) 358# and check that we can build with 32 bits if requested. 359if (CMAKE_SIZEOF_VOID_P EQUAL 8 AND NOT WIN32) 360 if (LIBCXX_BUILD_32_BITS AND NOT LLVM_BUILD_32_BITS) # Don't duplicate the output from LLVM 361 message(STATUS "Building 32 bits executables and libraries.") 362 endif() 363elseif(LIBCXX_BUILD_32_BITS) 364 message(FATAL_ERROR "LIBCXX_BUILD_32_BITS=ON is not supported on this platform.") 365endif() 366 367# Check that this option is not enabled on Apple and emit a usage warning. 368if (LIBCXX_ENABLE_STATIC_ABI_LIBRARY) 369 if (APPLE) 370 message(FATAL_ERROR "LIBCXX_ENABLE_STATIC_ABI_LIBRARY is not supported on OS X") 371 else() 372 message(WARNING "LIBCXX_ENABLE_STATIC_ABI_LIBRARY is an experimental option") 373 endif() 374 if (LIBCXX_ENABLE_STATIC AND NOT PYTHONINTERP_FOUND) 375 message(FATAL_ERROR "LIBCXX_ENABLE_STATIC_ABI_LIBRARY requires python but it was not found.") 376 endif() 377endif() 378 379if (LIBCXX_ENABLE_ABI_LINKER_SCRIPT) 380 if (APPLE) 381 message(FATAL_ERROR "LIBCXX_ENABLE_ABI_LINKER_SCRIPT cannot be used on APPLE targets") 382 endif() 383 if (NOT PYTHONINTERP_FOUND) 384 message(FATAL_ERROR "LIBCXX_ENABLE_ABI_LINKER_SCRIPT requires python but it was not found.") 385 endif() 386 if (NOT LIBCXX_ENABLE_SHARED) 387 message(FATAL_ERROR "LIBCXX_ENABLE_ABI_LINKER_SCRIPT is only available for shared library builds.") 388 endif() 389endif() 390 391if (LIBCXX_STATICALLY_LINK_ABI_IN_SHARED_LIBRARY AND LIBCXX_ENABLE_ABI_LINKER_SCRIPT) 392 message(FATAL_ERROR "Conflicting options given. 393 LIBCXX_ENABLE_STATIC_ABI_LIBRARY cannot be specified with 394 LIBCXX_ENABLE_ABI_LINKER_SCRIPT") 395endif() 396 397if (LIBCXX_HAS_MUSL_LIBC AND NOT LIBCXX_INSTALL_SUPPORT_HEADERS) 398 message(FATAL_ERROR "LIBCXX_INSTALL_SUPPORT_HEADERS can not be turned off" 399 "when building for Musl with LIBCXX_HAS_MUSL_LIBC.") 400endif() 401 402if (LIBCXX_ABI_FORCE_ITANIUM AND LIBCXX_ABI_FORCE_MICROSOFT) 403 message(FATAL_ERROR "Only one of LIBCXX_ABI_FORCE_ITANIUM and LIBCXX_ABI_FORCE_MICROSOFT can be specified.") 404endif () 405 406#=============================================================================== 407# Configure System 408#=============================================================================== 409 410set(LIBCXX_COMPILER ${CMAKE_CXX_COMPILER}) 411set(LIBCXX_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}) 412set(LIBCXX_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR}) 413set(LIBCXX_BINARY_INCLUDE_DIR "${LIBCXX_BINARY_DIR}/include/c++build") 414 415string(REGEX MATCH "[0-9]+\\.[0-9]+(\\.[0-9]+)?" CLANG_VERSION 416 ${PACKAGE_VERSION}) 417 418if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE) 419 set(DEFAULT_INSTALL_PREFIX lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION}/${LLVM_DEFAULT_TARGET_TRIPLE}/) 420 set(DEFAULT_INSTALL_HEADER_PREFIX lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION}/) 421 set(LIBCXX_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION}/${LLVM_DEFAULT_TARGET_TRIPLE}/lib${LIBCXX_LIBDIR_SUFFIX}) 422 set(LIBCXX_HEADER_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION}) 423elseif(LLVM_LIBRARY_OUTPUT_INTDIR) 424 set(LIBCXX_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}) 425 set(LIBCXX_HEADER_DIR ${LLVM_BINARY_DIR}) 426else() 427 set(LIBCXX_LIBRARY_DIR ${CMAKE_BINARY_DIR}/lib${LIBCXX_LIBDIR_SUFFIX}) 428endif() 429 430file(MAKE_DIRECTORY "${LIBCXX_BINARY_INCLUDE_DIR}") 431 432set(LIBCXX_INSTALL_PREFIX ${DEFAULT_INSTALL_PREFIX} CACHE STRING 433 "Define libc++ destination prefix.") 434 435set(LIBCXX_INSTALL_HEADER_PREFIX ${DEFAULT_INSTALL_HEADER_PREFIX} CACHE STRING 436 "Define libc++ header destination prefix.") 437 438set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LIBCXX_LIBRARY_DIR}) 439set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LIBCXX_LIBRARY_DIR}) 440set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${LIBCXX_LIBRARY_DIR}) 441 442# Declare libc++ configuration variables. 443# They are intended for use as follows: 444# LIBCXX_CXX_FLAGS: General flags for both the compiler and linker. 445# LIBCXX_COMPILE_FLAGS: Compile only flags. 446# LIBCXX_LINK_FLAGS: Linker only flags. 447# LIBCXX_LIBRARIES: libraries libc++ is linked to. 448# LIBCXX_INTERFACE_LIBRARIES: Libraries that must be linked when using libc++ 449# These libraries are exposed in the linker script. 450set(LIBCXX_COMPILE_FLAGS "") 451set(LIBCXX_LINK_FLAGS "") 452set(LIBCXX_LIBRARIES "") 453set(LIBCXX_INTERFACE_LIBRARIES "") 454 455# Include macros for adding and removing libc++ flags. 456include(HandleLibcxxFlags) 457 458# Target flags ================================================================ 459# These flags get added to CMAKE_CXX_FLAGS and CMAKE_C_FLAGS so that 460# 'config-ix' use them during feature checks. It also adds them to both 461# 'LIBCXX_COMPILE_FLAGS' and 'LIBCXX_LINK_FLAGS' 462add_target_flags_if(LIBCXX_BUILD_32_BITS "-m32") 463add_target_flags_if(LIBCXX_TARGET_TRIPLE "--target=${LIBCXX_TARGET_TRIPLE}") 464add_target_flags_if(LIBCXX_SYSROOT "--sysroot=${LIBCXX_SYSROOT}") 465add_target_flags_if(LIBCXX_GCC_TOOLCHAIN "--gcc-toolchain=${LIBCXX_GCC_TOOLCHAIN}") 466if (LIBCXX_TARGET_TRIPLE) 467 set(TARGET_TRIPLE "${LIBCXX_TARGET_TRIPLE}") 468endif() 469 470# Configure compiler. 471include(config-ix) 472 473if (LIBCXX_USE_COMPILER_RT) 474 list(APPEND LIBCXX_LINK_FLAGS "-rtlib=compiler-rt") 475endif() 476 477# Configure coverage options. 478if (LIBCXX_GENERATE_COVERAGE) 479 include(CodeCoverage) 480 set(CMAKE_BUILD_TYPE "COVERAGE" CACHE STRING "" FORCE) 481endif() 482 483string(TOUPPER "${CMAKE_BUILD_TYPE}" uppercase_CMAKE_BUILD_TYPE) 484if (uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG") 485 set(LIBCXX_DEBUG_BUILD ON) 486else() 487 set(LIBCXX_DEBUG_BUILD OFF) 488endif() 489 490#=============================================================================== 491# Setup Compiler Flags 492#=============================================================================== 493 494include(HandleLibCXXABI) # Setup the ABI library flags 495 496if (NOT LIBCXX_STANDALONE_BUILD) 497 # Remove flags that may have snuck in. 498 remove_flags(-DNDEBUG -UNDEBUG -D_DEBUG 499 -lc++abi) 500endif() 501remove_flags(-stdlib=libc++ -stdlib=libstdc++) 502 503# FIXME: Remove all debug flags and flags that change which Windows 504# default libraries are linked. Currently we only support linking the 505# non-debug DLLs 506remove_flags("/D_DEBUG" "/MTd" "/MDd" "/MT" "/Md") 507 508# FIXME(EricWF): See the FIXME on LIBCXX_ENABLE_PEDANTIC. 509# Remove the -pedantic flag and -Wno-pedantic and -pedantic-errors 510# so they don't get transformed into -Wno and -errors respectively. 511remove_flags(-Wno-pedantic -pedantic-errors -pedantic) 512 513# Required flags ============================================================== 514set(LIBCXX_STANDARD_VER c++11 CACHE INTERNAL "internal option to change build dialect") 515if (LIBCXX_HAS_MUSL_LIBC OR LIBCXX_TARGETING_CLANG_CL) 516 # musl's pthread implementations uses volatile types in their structs which is 517 # not a constexpr in C++11 but is in C++14, so we use C++14 with musl. 518 set(LIBCXX_STANDARD_VER c++14 CACHE INTERNAL "internal option to change build dialect") 519endif() 520add_compile_flags_if_supported(-std=${LIBCXX_STANDARD_VER}) 521add_compile_flags_if_supported("/std:${LIBCXX_STANDARD_VER}") 522mangle_name("LIBCXX_SUPPORTS_STD_EQ_${LIBCXX_STANDARD_VER}_FLAG" SUPPORTS_DIALECT_NAME) 523mangle_name("LIBCXX_SUPPORTS_STD_COLON_${LIBCXX_STANDARD_VER}_FLAG" SUPPORTS_DIALECT_NAME_MSVC) 524if(NOT ${SUPPORTS_DIALECT_NAME} AND NOT ${SUPPORTS_DIALECT_NAME_MSVC}) 525 if(NOT "${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC" AND NOT "${CMAKE_CXX_SIMULATE_ID}" STREQUAL "MSVC") 526 message(FATAL_ERROR "C++11 or greater is required but the compiler does not support ${LIBCXX_STANDARD_VER}") 527 endif() 528endif() 529 530# On all systems the system c++ standard library headers need to be excluded. 531# MSVC only has -X, which disables all default includes; including the crt. 532# Thus, we do nothing and hope we don't accidentally include any of the C++ 533# headers 534add_compile_flags_if_supported(-nostdinc++) 535 536# Hide all inline function definitions which have not explicitly been marked 537# visible. This prevents new definitions for inline functions from appearing in 538# the dylib when get ODR used by another function. 539add_compile_flags_if_supported(-fvisibility-inlines-hidden) 540 541if (LIBCXX_CONFIGURE_IDE) 542 # This simply allows IDE to process <experimental/coroutine> 543 add_compile_flags_if_supported(-fcoroutines-ts) 544endif() 545 546# Let the library headers know they are currently being used to build the 547# library. 548add_definitions(-D_LIBCPP_BUILDING_LIBRARY) 549 550if (NOT LIBCXX_ENABLE_NEW_DELETE_DEFINITIONS) 551 add_definitions(-D_LIBCPP_DISABLE_NEW_DELETE_DEFINITIONS) 552endif() 553 554# Warning flags =============================================================== 555add_definitions(-D_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 556add_compile_flags_if_supported( 557 -Wall -Wextra -W -Wwrite-strings 558 -Wno-unused-parameter -Wno-long-long 559 -Werror=return-type -Wextra-semi) 560if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang") 561 add_compile_flags_if_supported( 562 -Wno-user-defined-literals 563 -Wno-covered-switch-default) 564 if (LIBCXX_TARGETING_CLANG_CL) 565 add_compile_flags_if_supported( 566 -Wno-c++98-compat 567 -Wno-c++98-compat-pedantic 568 -Wno-c++11-compat 569 -Wno-undef 570 -Wno-reserved-id-macro 571 -Wno-gnu-include-next 572 -Wno-gcc-compat # For ignoring "'diagnose_if' is a clang extension" warnings 573 -Wno-zero-as-null-pointer-constant # FIXME: Remove this and fix all occurrences. 574 -Wno-deprecated-dynamic-exception-spec # For auto_ptr 575 -Wno-sign-conversion 576 -Wno-old-style-cast 577 -Wno-deprecated # FIXME: Remove this and fix all occurrences. 578 -Wno-shift-sign-overflow # FIXME: Why do we need this with clang-cl but not clang? 579 -Wno-double-promotion # FIXME: remove me 580 ) 581 endif() 582elseif("${CMAKE_CXX_COMPILER_ID}" MATCHES "GNU") 583 add_compile_flags_if_supported( 584 -Wno-literal-suffix 585 -Wno-c++14-compat 586 -Wno-noexcept-type) 587endif() 588if (LIBCXX_ENABLE_WERROR) 589 add_compile_flags_if_supported(-Werror) 590 add_compile_flags_if_supported(-WX) 591else() 592 # TODO(EricWF) Remove this. We shouldn't be suppressing errors when -Werror is 593 # added elsewhere. 594 add_compile_flags_if_supported(-Wno-error) 595endif() 596if (LIBCXX_ENABLE_PEDANTIC) 597 add_compile_flags_if_supported(-pedantic) 598endif() 599if (LIBCXX_DISABLE_MACRO_CONFLICT_WARNINGS) 600 add_definitions(-D_LIBCPP_DISABLE_MACRO_CONFLICT_WARNINGS) 601endif() 602 603# Exception flags ============================================================= 604if (LIBCXX_ENABLE_EXCEPTIONS) 605 # Catches C++ exceptions only and tells the compiler to assume that extern C 606 # functions never throw a C++ exception. 607 add_compile_flags_if_supported(-EHsc) 608else() 609 add_definitions(-D_LIBCPP_NO_EXCEPTIONS) 610 add_compile_flags_if_supported(-EHs- -EHa-) 611 add_compile_flags_if_supported(-fno-exceptions) 612endif() 613 614# RTTI flags ================================================================== 615if (NOT LIBCXX_ENABLE_RTTI) 616 add_definitions(-D_LIBCPP_NO_RTTI) 617 add_compile_flags_if_supported(-GR-) 618 add_compile_flags_if_supported(-fno-rtti) 619endif() 620 621# Threading flags ============================================================= 622if (LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY AND LIBCXX_ENABLE_SHARED) 623 # Need to allow unresolved symbols if this is to work with shared library builds 624 if (APPLE) 625 add_link_flags("-undefined dynamic_lookup") 626 else() 627 # Relax this restriction from HandleLLVMOptions 628 string(REPLACE "-Wl,-z,defs" "" CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS}") 629 endif() 630endif() 631 632# Assertion flags ============================================================= 633define_if(LIBCXX_ENABLE_ASSERTIONS -UNDEBUG) 634define_if_not(LIBCXX_ENABLE_ASSERTIONS -DNDEBUG) 635define_if(LIBCXX_ENABLE_ASSERTIONS -D_LIBCPP_DEBUG=0) 636define_if(LIBCXX_DEBUG_BUILD -D_DEBUG) 637if (LIBCXX_ENABLE_ASSERTIONS AND NOT LIBCXX_DEBUG_BUILD) 638 # MSVC doesn't like _DEBUG on release builds. See PR 4379. 639 define_if_not(LIBCXX_TARGETING_MSVC -D_DEBUG) 640endif() 641 642# Modules flags =============================================================== 643# FIXME The libc++ sources are fundamentally non-modular. They need special 644# versions of the headers in order to provide C++03 and legacy ABI definitions. 645# NOTE: The public headers can be used with modules in all other contexts. 646if (LLVM_ENABLE_MODULES) 647 # Ignore that the rest of the modules flags are now unused. 648 add_compile_flags_if_supported(-Wno-unused-command-line-argument) 649 add_compile_flags(-fno-modules) 650endif() 651 652# Sanitizer flags ============================================================= 653 654function(get_sanitizer_flags OUT_VAR USE_SANITIZER) 655 set(SANITIZER_FLAGS) 656 set(USE_SANITIZER "${USE_SANITIZER}") 657 # NOTE: LLVM_USE_SANITIZER checks for a UNIX like system instead of MSVC. 658 # But we don't have LLVM_ON_UNIX so checking for MSVC is the best we can do. 659 if (USE_SANITIZER AND NOT MSVC) 660 append_flags_if_supported(SANITIZER_FLAGS "-fno-omit-frame-pointer") 661 append_flags_if_supported(SANITIZER_FLAGS "-gline-tables-only") 662 663 if (NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "DEBUG" AND 664 NOT uppercase_CMAKE_BUILD_TYPE STREQUAL "RELWITHDEBINFO") 665 append_flags_if_supported(SANITIZER_FLAGS "-gline-tables-only") 666 endif() 667 if (USE_SANITIZER STREQUAL "Address") 668 append_flags(SANITIZER_FLAGS "-fsanitize=address") 669 elseif (USE_SANITIZER MATCHES "Memory(WithOrigins)?") 670 append_flags(SANITIZER_FLAGS -fsanitize=memory) 671 if (USE_SANITIZER STREQUAL "MemoryWithOrigins") 672 append_flags(SANITIZER_FLAGS "-fsanitize-memory-track-origins") 673 endif() 674 elseif (USE_SANITIZER STREQUAL "Undefined") 675 append_flags(SANITIZER_FLAGS "-fsanitize=undefined -fno-sanitize=vptr,function -fno-sanitize-recover=all") 676 elseif (USE_SANITIZER STREQUAL "Thread") 677 append_flags(SANITIZER_FLAGS -fsanitize=thread) 678 else() 679 message(WARNING "Unsupported value of LLVM_USE_SANITIZER: ${USE_SANITIZER}") 680 endif() 681 elseif(USE_SANITIZER AND MSVC) 682 message(WARNING "LLVM_USE_SANITIZER is not supported on this platform.") 683 endif() 684 set(${OUT_VAR} "${SANITIZER_FLAGS}" PARENT_SCOPE) 685endfunction() 686 687# Configure for sanitizers. If LIBCXX_STANDALONE_BUILD then we have to do 688# the flag translation ourselves. Othewise LLVM's CMakeList.txt will handle it. 689if (LIBCXX_STANDALONE_BUILD) 690 set(LLVM_USE_SANITIZER "" CACHE STRING 691 "Define the sanitizer used to build the library and tests") 692endif() 693get_sanitizer_flags(SANITIZER_FLAGS "${LLVM_USE_SANITIZER}") 694if (LIBCXX_STANDALONE_BUILD AND SANITIZER_FLAGS) 695 add_flags(${SANITIZER_FLAGS}) 696endif() 697 698# Configuration file flags ===================================================== 699if (NOT LIBCXX_ABI_VERSION EQUAL 1) 700 config_define(${LIBCXX_ABI_VERSION} _LIBCPP_ABI_VERSION) 701endif() 702if (NOT LIBCXX_ABI_NAMESPACE STREQUAL "") 703 if (NOT LIBCXX_ABI_NAMESPACE MATCHES "__.*") 704 message(WARNING "LIBCXX_ABI_NAMESPACE must be a reserved identifier.") 705 endif() 706 if (LIBCXX_ABI_NAMESPACE MATCHES "__[0-9]+$") 707 message(FATAL_ERROR "LIBCXX_ABI_NAMESPACE '${LIBCXX_ABI_NAMESPACE}' is reserved for use by libc++.") 708 endif() 709 config_define(${LIBCXX_ABI_NAMESPACE} _LIBCPP_ABI_NAMESPACE) 710endif() 711config_define_if(LIBCXX_ABI_UNSTABLE _LIBCPP_ABI_UNSTABLE) 712config_define_if(LIBCXX_ABI_FORCE_ITANIUM _LIBCPP_ABI_FORCE_ITANIUM) 713config_define_if(LIBCXX_ABI_FORCE_MICROSOFT _LIBCPP_ABI_FORCE_MICROSOFT) 714config_define_if(LIBCXX_HIDE_FROM_ABI_PER_TU_BY_DEFAULT _LIBCPP_HIDE_FROM_ABI_PER_TU_BY_DEFAULT) 715 716config_define_if_not(LIBCXX_ENABLE_GLOBAL_FILESYSTEM_NAMESPACE _LIBCPP_HAS_NO_GLOBAL_FILESYSTEM_NAMESPACE) 717config_define_if_not(LIBCXX_ENABLE_STDIN _LIBCPP_HAS_NO_STDIN) 718config_define_if_not(LIBCXX_ENABLE_STDOUT _LIBCPP_HAS_NO_STDOUT) 719config_define_if_not(LIBCXX_ENABLE_THREADS _LIBCPP_HAS_NO_THREADS) 720config_define_if_not(LIBCXX_ENABLE_MONOTONIC_CLOCK _LIBCPP_HAS_NO_MONOTONIC_CLOCK) 721config_define_if_not(LIBCXX_ENABLE_THREAD_UNSAFE_C_FUNCTIONS _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS) 722 723config_define_if(LIBCXX_HAS_PTHREAD_API _LIBCPP_HAS_THREAD_API_PTHREAD) 724config_define_if(LIBCXX_HAS_EXTERNAL_THREAD_API _LIBCPP_HAS_THREAD_API_EXTERNAL) 725config_define_if(LIBCXX_HAS_WIN32_THREAD_API _LIBCPP_HAS_THREAD_API_WIN32) 726config_define_if(LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY _LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL) 727config_define_if(LIBCXX_HAS_MUSL_LIBC _LIBCPP_HAS_MUSL_LIBC) 728config_define_if(LIBCXX_NO_VCRUNTIME _LIBCPP_NO_VCRUNTIME) 729 730if (LIBCXX_ABI_DEFINES) 731 set(abi_defines) 732 foreach (abi_define ${LIBCXX_ABI_DEFINES}) 733 if (NOT abi_define MATCHES "^_LIBCPP_ABI_") 734 message(SEND_ERROR "Invalid ABI macro ${abi_define} in LIBCXX_ABI_DEFINES") 735 endif() 736 list(APPEND abi_defines "#define ${abi_define}") 737 endforeach() 738 string(REPLACE ";" "\n" abi_defines "${abi_defines}") 739 config_define(${abi_defines} _LIBCPP_ABI_DEFINES) 740endif() 741 742# By default libc++ on Windows expects to use a shared library, which requires 743# the headers to use DLL import/export semantics. However when building a 744# static library only we modify the headers to disable DLL import/export. 745if (DEFINED WIN32 AND LIBCXX_ENABLE_STATIC AND NOT LIBCXX_ENABLE_SHARED) 746 message(STATUS "Generating custom __config for non-DLL Windows build") 747 config_define(ON _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS) 748endif() 749 750set(site_config_path "${LIBCXX_BINARY_DIR}/__config_site") 751if (LIBCXX_NEEDS_SITE_CONFIG) 752 configure_file("include/__config_site.in" 753 "${site_config_path}" 754 @ONLY) 755 756 # Provide the config definitions by included the generated __config_site 757 # file at compile time. 758 if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC" OR "${CMAKE_CXX_SIMULATE_ID}" STREQUAL "MSVC") 759 add_compile_flags("/FI\"${LIBCXX_BINARY_DIR}/__config_site\"") 760 else() 761 add_compile_flags("-include ${LIBCXX_BINARY_DIR}/__config_site") 762 endif() 763else() 764 if (EXISTS "${site_config_path}") 765 message(STATUS "Removing stale site configuration ${site_config_path}") 766 file(REMOVE "${site_config_path}") 767 endif() 768endif() 769 770#=============================================================================== 771# Setup Source Code And Tests 772#=============================================================================== 773include_directories(include) 774add_subdirectory(include) 775add_subdirectory(lib) 776 777set(LIBCXX_TEST_DEPS "") 778 779if (LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY) 780 list(APPEND LIBCXX_TEST_DEPS cxx_experimental) 781endif() 782if (LIBCXX_ENABLE_FILESYSTEM) 783 list(APPEND LIBCXX_TEST_DEPS cxx_filesystem) 784endif() 785 786if (LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY) 787 list(APPEND LIBCXX_TEST_DEPS cxx_external_threads) 788endif() 789 790if (LIBCXX_INCLUDE_BENCHMARKS) 791 add_subdirectory(benchmarks) 792endif() 793 794# Create the lit.site.cfg file even when LIBCXX_INCLUDE_TESTS is OFF or 795# LLVM_FOUND is OFF. This allows users to run the tests manually using 796# LIT without requiring a full LLVM checkout. 797# 798# However, since some submission systems strip test/ subdirectories, check for 799# it before adding it. 800 801if(IS_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/test") 802 add_subdirectory(test) 803endif() 804if (LIBCXX_INCLUDE_TESTS) 805 add_subdirectory(lib/abi) 806endif() 807 808if (LIBCXX_STANDALONE_BUILD AND EXISTS "${LLVM_MAIN_SRC_DIR}/utils/llvm-lit") 809 include(AddLLVM) # for get_llvm_lit_path 810 # Make sure the llvm-lit script is generated into the bin directory, and do 811 # it after adding all tests, since the generated script will only work 812 # correctly discovered tests against test locations from the source tree that 813 # have already been discovered. 814 add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/llvm-lit 815 ${CMAKE_CURRENT_BINARY_DIR}/llvm-lit) 816endif() 817 818if (LIBCXX_INCLUDE_DOCS) 819 add_subdirectory(docs) 820endif() 821