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1include(CheckLibraryExists)
2include(CheckCCompilerFlag)
3include(CheckCXXCompilerFlag)
4
5if(WIN32 AND NOT MINGW)
6  # NOTE(compnerd) this is technically a lie, there is msvcrt, but for now, lets
7  # let the default linking take care of that.
8  set(LIBCXX_HAS_C_LIB NO)
9else()
10  check_library_exists(c fopen "" LIBCXX_HAS_C_LIB)
11endif()
12
13if (NOT LIBCXX_USE_COMPILER_RT)
14  if(WIN32 AND NOT MINGW)
15    set(LIBCXX_HAS_GCC_S_LIB NO)
16  else()
17    check_library_exists(gcc_s __gcc_personality_v0 "" LIBCXX_HAS_GCC_S_LIB)
18  endif()
19endif()
20
21# libc++ is built with -nodefaultlibs, so we want all our checks to also
22# use this option, otherwise we may end up with an inconsistency between
23# the flags we think we require during configuration (if the checks are
24# performed without -nodefaultlibs) and the flags that are actually
25# required during compilation (which has the -nodefaultlibs). libc is
26# required for the link to go through. We remove sanitizers from the
27# configuration checks to avoid spurious link errors.
28check_c_compiler_flag(-nodefaultlibs LIBCXX_SUPPORTS_NODEFAULTLIBS_FLAG)
29if (LIBCXX_SUPPORTS_NODEFAULTLIBS_FLAG)
30  set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -nodefaultlibs")
31  if (LIBCXX_HAS_C_LIB)
32    list(APPEND CMAKE_REQUIRED_LIBRARIES c)
33  endif ()
34  if (LIBCXX_USE_COMPILER_RT)
35    list(APPEND CMAKE_REQUIRED_FLAGS -rtlib=compiler-rt)
36    find_compiler_rt_library(builtins LIBCXX_BUILTINS_LIBRARY)
37    list(APPEND CMAKE_REQUIRED_LIBRARIES "${LIBCXX_BUILTINS_LIBRARY}")
38  elseif (LIBCXX_HAS_GCC_S_LIB)
39    list(APPEND CMAKE_REQUIRED_LIBRARIES gcc_s)
40  endif ()
41  if (MINGW)
42    # Mingw64 requires quite a few "C" runtime libraries in order for basic
43    # programs to link successfully with -nodefaultlibs.
44    if (LIBCXX_USE_COMPILER_RT)
45      set(MINGW_RUNTIME ${LIBCXX_BUILTINS_LIBRARY})
46    else ()
47      set(MINGW_RUNTIME gcc_s gcc)
48    endif()
49    set(MINGW_LIBRARIES mingw32 ${MINGW_RUNTIME} moldname mingwex msvcrt advapi32
50                        shell32 user32 kernel32 mingw32 ${MINGW_RUNTIME}
51                        moldname mingwex msvcrt)
52    list(APPEND CMAKE_REQUIRED_LIBRARIES ${MINGW_LIBRARIES})
53  endif()
54  if (CMAKE_C_FLAGS MATCHES -fsanitize OR CMAKE_CXX_FLAGS MATCHES -fsanitize)
55    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -fno-sanitize=all")
56  endif ()
57  if (CMAKE_C_FLAGS MATCHES -fsanitize-coverage OR CMAKE_CXX_FLAGS MATCHES -fsanitize-coverage)
58    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -fno-sanitize-coverage=edge,trace-cmp,indirect-calls,8bit-counters")
59  endif ()
60endif ()
61
62if(NOT WIN32 OR MINGW)
63  include(CheckLibcxxAtomic)
64endif()
65
66# Check compiler flags
67
68check_cxx_compiler_flag(/WX                     LIBCXX_HAS_WX_FLAG)
69check_cxx_compiler_flag(/WX-                    LIBCXX_HAS_NO_WX_FLAG)
70check_cxx_compiler_flag(/EHsc                   LIBCXX_HAS_EHSC_FLAG)
71check_cxx_compiler_flag(/EHs-                   LIBCXX_HAS_NO_EHS_FLAG)
72check_cxx_compiler_flag(/EHa-                   LIBCXX_HAS_NO_EHA_FLAG)
73check_cxx_compiler_flag(/GR-                    LIBCXX_HAS_NO_GR_FLAG)
74
75
76# Check libraries
77if(WIN32 AND NOT MINGW)
78  # TODO(compnerd) do we want to support an emulation layer that allows for the
79  # use of pthread-win32 or similar libraries to emulate pthreads on Windows?
80  set(LIBCXX_HAS_PTHREAD_LIB NO)
81  set(LIBCXX_HAS_M_LIB NO)
82  set(LIBCXX_HAS_RT_LIB NO)
83else()
84  check_library_exists(pthread pthread_create "" LIBCXX_HAS_PTHREAD_LIB)
85  check_library_exists(m ccos "" LIBCXX_HAS_M_LIB)
86  check_library_exists(rt clock_gettime "" LIBCXX_HAS_RT_LIB)
87endif()
88