1 # Distributed under the OSI-approved BSD 3-Clause License. See accompanying
2 # file Copyright.txt or https://cmake.org/licensing for details.
5 # determine the compiler to use for C++ programs
6 # NOTE, a generator may set CMAKE_CXX_COMPILER before
7 # loading this file to force a compiler.
8 # use environment variable CXX first if defined by user, next use
9 # the cmake variable CMAKE_GENERATOR_CXX which can be defined by a generator
10 # as a default compiler
11 # If the internal cmake variable _CMAKE_TOOLCHAIN_PREFIX is set, this is used
12 # as prefix for the tools (e.g. arm-elf-g++, arm-elf-ar etc.)
14 # Sets the following variables:
16 # CMAKE_COMPILER_IS_GNUCXX
20 # If not already set before, it also sets
21 # _CMAKE_TOOLCHAIN_PREFIX
23 include(${CMAKE_ROOT}/Modules/CMakeDetermineCompiler.cmake)
25 # Load system-specific compiler preferences for this language.
26 include(Platform/${CMAKE_SYSTEM_NAME}-Determine-CXX OPTIONAL)
27 include(Platform/${CMAKE_SYSTEM_NAME}-CXX OPTIONAL)
28 if(NOT CMAKE_CXX_COMPILER_NAMES)
29 set(CMAKE_CXX_COMPILER_NAMES CC)
32 if(${CMAKE_GENERATOR} MATCHES "Visual Studio")
33 elseif("${CMAKE_GENERATOR}" MATCHES "Green Hills MULTI")
34 elseif("${CMAKE_GENERATOR}" MATCHES "Xcode")
35 set(CMAKE_CXX_COMPILER_XCODE_TYPE sourcecode.cpp.cpp)
36 _cmake_find_compiler_path(CXX)
38 if(NOT CMAKE_CXX_COMPILER)
39 set(CMAKE_CXX_COMPILER_INIT NOTFOUND)
41 # prefer the environment variable CXX
42 if(NOT $ENV{CXX} STREQUAL "")
43 get_filename_component(CMAKE_CXX_COMPILER_INIT $ENV{CXX} PROGRAM PROGRAM_ARGS CMAKE_CXX_FLAGS_ENV_INIT)
44 if(CMAKE_CXX_FLAGS_ENV_INIT)
45 set(CMAKE_CXX_COMPILER_ARG1 "${CMAKE_CXX_FLAGS_ENV_INIT}" CACHE STRING "Arguments to CXX compiler")
47 if(NOT EXISTS ${CMAKE_CXX_COMPILER_INIT})
48 message(FATAL_ERROR "Could not find compiler set in environment variable CXX:\n$ENV{CXX}.\n${CMAKE_CXX_COMPILER_INIT}")
52 # next prefer the generator specified compiler
53 if(CMAKE_GENERATOR_CXX)
54 if(NOT CMAKE_CXX_COMPILER_INIT)
55 set(CMAKE_CXX_COMPILER_INIT ${CMAKE_GENERATOR_CXX})
59 # finally list compilers to try
60 if(NOT CMAKE_CXX_COMPILER_INIT)
61 set(CMAKE_CXX_COMPILER_LIST CC ${_CMAKE_TOOLCHAIN_PREFIX}c++ ${_CMAKE_TOOLCHAIN_PREFIX}g++ aCC cl bcc xlC)
62 if(NOT CMAKE_HOST_WIN32)
63 # FIXME(#24314): Add support for the GNU-like icpx compiler driver
64 # on Windows, first introduced by Intel oneAPI 2023.0.
65 list(APPEND CMAKE_CXX_COMPILER_LIST icpx)
67 list(APPEND CMAKE_CXX_COMPILER_LIST icx clang++)
70 _cmake_find_compiler(CXX)
72 _cmake_find_compiler_path(CXX)
74 mark_as_advanced(CMAKE_CXX_COMPILER)
76 # Each entry in this list is a set of extra flags to try
77 # adding to the compile line to see if it helps produce
78 # a valid identification file.
79 set(CMAKE_CXX_COMPILER_ID_TEST_FLAGS_FIRST)
80 set(CMAKE_CXX_COMPILER_ID_TEST_FLAGS
81 # Try compiling to an object file only.
83 # IAR does not detect language automatically
87 # ARMClang need target options
88 "--target=arm-arm-none-eabi -mcpu=cortex-m3"
90 # MSVC needs at least one include directory for __has_include to function,
91 # but custom toolchains may run MSVC with no INCLUDE env var and no -I flags.
92 # Also avoid linking so this works with no LIB env var.
93 "-c -I__does_not_exist__"
97 if(CMAKE_CXX_COMPILER_TARGET)
98 set(CMAKE_CXX_COMPILER_ID_TEST_FLAGS_FIRST "-c --target=${CMAKE_CXX_COMPILER_TARGET}")
101 # Build a small source file to identify the compiler.
102 if(NOT CMAKE_CXX_COMPILER_ID_RUN)
103 set(CMAKE_CXX_COMPILER_ID_RUN 1)
105 # Try to identify the compiler.
106 set(CMAKE_CXX_COMPILER_ID)
107 set(CMAKE_CXX_PLATFORM_ID)
108 file(READ ${CMAKE_ROOT}/Modules/CMakePlatformId.h.in
109 CMAKE_CXX_COMPILER_ID_PLATFORM_CONTENT)
111 # The IAR compiler produces weird output.
112 # See https://gitlab.kitware.com/cmake/cmake/-/issues/10176#note_153591
113 list(APPEND CMAKE_CXX_COMPILER_ID_VENDORS IAR)
114 set(CMAKE_CXX_COMPILER_ID_VENDOR_FLAGS_IAR )
115 set(CMAKE_CXX_COMPILER_ID_VENDOR_REGEX_IAR "IAR .+ Compiler")
117 # Match the link line from xcodebuild output of the form
120 # /path/to/cc ...CompilerIdCXX/...
121 # to extract the compiler front-end for the language.
122 set(CMAKE_CXX_COMPILER_ID_TOOL_MATCH_REGEX "\nLd[^\n]*(\n[ \t]+[^\n]*)*\n[ \t]+([^ \t\r\n]+)[^\r\n]*-o[^\r\n]*CompilerIdCXX/(\\./)?(CompilerIdCXX.(framework|xctest|build/[^ \t\r\n]+)/)?CompilerIdCXX[ \t\n\\\"]")
123 set(CMAKE_CXX_COMPILER_ID_TOOL_MATCH_INDEX 2)
125 include(${CMAKE_ROOT}/Modules/CMakeDetermineCompilerId.cmake)
126 CMAKE_DETERMINE_COMPILER_ID(CXX CXXFLAGS CMakeCXXCompilerId.cpp)
128 _cmake_find_compiler_sysroot(CXX)
130 # Set old compiler and platform id variables.
131 if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
132 set(CMAKE_COMPILER_IS_GNUCXX 1)
135 if(NOT DEFINED CMAKE_CXX_COMPILER_FRONTEND_VARIANT)
136 # Some toolchain files set our internal CMAKE_CXX_COMPILER_ID_RUN
137 # variable but are not aware of CMAKE_CXX_COMPILER_FRONTEND_VARIANT.
138 # They pre-date our support for the GNU-like variant targeting the
139 # MSVC ABI so we do not consider that here.
140 if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang"
141 OR "x${CMAKE_CXX_COMPILER_ID}" STREQUAL "xIntelLLVM")
142 if("x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
143 set(CMAKE_CXX_COMPILER_FRONTEND_VARIANT "MSVC")
145 set(CMAKE_CXX_COMPILER_FRONTEND_VARIANT "GNU")
148 set(CMAKE_CXX_COMPILER_FRONTEND_VARIANT "")
153 if (NOT _CMAKE_TOOLCHAIN_LOCATION)
154 get_filename_component(_CMAKE_TOOLCHAIN_LOCATION "${CMAKE_CXX_COMPILER}" PATH)
157 # if we have a g++ cross compiler, they have usually some prefix, like
158 # e.g. powerpc-linux-g++, arm-elf-g++ or i586-mingw32msvc-g++ , optionally
159 # with a 3-component version number at the end (e.g. arm-eabi-gcc-4.5.2).
160 # The other tools of the toolchain usually have the same prefix
161 # NAME_WE cannot be used since then this test will fail for names like
162 # "arm-unknown-nto-qnx6.3.0-gcc.exe", where BASENAME would be
163 # "arm-unknown-nto-qnx6" instead of the correct "arm-unknown-nto-qnx6.3.0-"
166 if (NOT _CMAKE_TOOLCHAIN_PREFIX)
168 if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang|QCC|LCC")
169 get_filename_component(COMPILER_BASENAME "${CMAKE_CXX_COMPILER}" NAME)
170 if (COMPILER_BASENAME MATCHES "^(.+-)?(clang\\+\\+|[gc]\\+\\+|clang-cl)(-?[0-9]+(\\.[0-9]+)*)?(-[^.]+)?(\\.exe)?$")
171 set(_CMAKE_TOOLCHAIN_PREFIX ${CMAKE_MATCH_1})
172 set(_CMAKE_TOOLCHAIN_SUFFIX ${CMAKE_MATCH_3})
173 set(_CMAKE_COMPILER_SUFFIX ${CMAKE_MATCH_5})
174 elseif(CMAKE_CXX_COMPILER_ID MATCHES "TIClang")
175 if (COMPILER_BASENAME MATCHES "^(.+)?clang(\\.exe)?$")
176 set(_CMAKE_TOOLCHAIN_PREFIX "${CMAKE_MATCH_1}")
177 set(_CMAKE_TOOLCHAIN_SUFFIX "${CMAKE_MATCH_2}")
179 elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
180 if(CMAKE_CXX_COMPILER_TARGET)
181 set(_CMAKE_TOOLCHAIN_PREFIX ${CMAKE_CXX_COMPILER_TARGET}-)
183 elseif(COMPILER_BASENAME MATCHES "QCC(\\.exe)?$")
184 if(CMAKE_CXX_COMPILER_TARGET MATCHES "gcc_nto([a-z0-9]+_[0-9]+|[^_le]+)(le)")
185 set(_CMAKE_TOOLCHAIN_PREFIX nto${CMAKE_MATCH_1}-)
189 # if "llvm-" is part of the prefix, remove it, since llvm doesn't have its own binutils
190 # but uses the regular ar, objcopy, etc. (instead of llvm-objcopy etc.)
191 if ("${_CMAKE_TOOLCHAIN_PREFIX}" MATCHES "(.+-)?llvm-$")
192 set(_CMAKE_TOOLCHAIN_PREFIX ${CMAKE_MATCH_1})
194 elseif(CMAKE_CXX_COMPILER_ID MATCHES "TI")
195 # TI compilers are named e.g. cl6x, cl470 or armcl.exe
196 get_filename_component(COMPILER_BASENAME "${CMAKE_CXX_COMPILER}" NAME)
197 if (COMPILER_BASENAME MATCHES "^(.+)?cl([^.]+)?(\\.exe)?$")
198 set(_CMAKE_TOOLCHAIN_PREFIX "${CMAKE_MATCH_1}")
199 set(_CMAKE_TOOLCHAIN_SUFFIX "${CMAKE_MATCH_2}")
206 set(_CMAKE_PROCESSING_LANGUAGE "CXX")
207 include(CMakeFindBinUtils)
208 include(Compiler/${CMAKE_CXX_COMPILER_ID}-FindBinUtils OPTIONAL)
209 unset(_CMAKE_PROCESSING_LANGUAGE)
211 if(CMAKE_CXX_COMPILER_SYSROOT)
212 string(CONCAT _SET_CMAKE_CXX_COMPILER_SYSROOT
213 "set(CMAKE_CXX_COMPILER_SYSROOT \"${CMAKE_CXX_COMPILER_SYSROOT}\")\n"
214 "set(CMAKE_COMPILER_SYSROOT \"${CMAKE_CXX_COMPILER_SYSROOT}\")")
216 set(_SET_CMAKE_CXX_COMPILER_SYSROOT "")
219 if(CMAKE_CXX_COMPILER_ARCHITECTURE_ID)
220 set(_SET_CMAKE_CXX_COMPILER_ARCHITECTURE_ID
221 "set(CMAKE_CXX_COMPILER_ARCHITECTURE_ID ${CMAKE_CXX_COMPILER_ARCHITECTURE_ID})")
223 set(_SET_CMAKE_CXX_COMPILER_ARCHITECTURE_ID "")
226 if(MSVC_CXX_ARCHITECTURE_ID)
227 set(SET_MSVC_CXX_ARCHITECTURE_ID
228 "set(MSVC_CXX_ARCHITECTURE_ID ${MSVC_CXX_ARCHITECTURE_ID})")
231 if(CMAKE_CXX_XCODE_ARCHS)
232 set(SET_CMAKE_XCODE_ARCHS
233 "set(CMAKE_XCODE_ARCHS \"${CMAKE_CXX_XCODE_ARCHS}\")")
236 # configure all variables set in this file
237 configure_file(${CMAKE_ROOT}/Modules/CMakeCXXCompiler.cmake.in
238 ${CMAKE_PLATFORM_INFO_DIR}/CMakeCXXCompiler.cmake
242 set(CMAKE_CXX_COMPILER_ENV_VAR "CXX")