1# Check if the host compiler is new enough.
2# These versions are updated based on the following policy:
3#   llvm.org/docs/DeveloperPolicy.html#toolchain
4
5include(CheckCXXSourceCompiles)
6
7set(GCC_MIN 5.1)
8set(GCC_SOFT_ERROR 5.1)
9set(CLANG_MIN 3.5)
10set(CLANG_SOFT_ERROR 3.5)
11set(APPLECLANG_MIN 6.0)
12set(APPLECLANG_SOFT_ERROR 6.0)
13
14# https://en.wikipedia.org/wiki/Microsoft_Visual_C#Internal_version_numbering
15# _MSC_VER == 1910 MSVC++ 14.1 (Visual Studio 2017 version 15.0)
16set(MSVC_MIN 19.1)
17set(MSVC_SOFT_ERROR 19.1)
18
19# Map the above GCC versions to dates: https://gcc.gnu.org/develop.html#timeline
20set(GCC_MIN_DATE 20150422)
21set(GCC_SOFT_ERROR_DATE 20150422)
22
23
24if(DEFINED LLVM_COMPILER_CHECKED)
25  return()
26endif()
27set(LLVM_COMPILER_CHECKED ON)
28
29if(LLVM_FORCE_USE_OLD_TOOLCHAIN)
30  return()
31endif()
32
33function(check_compiler_version NAME NICE_NAME MINIMUM_VERSION SOFT_ERROR_VERSION)
34  if(NOT CMAKE_CXX_COMPILER_ID STREQUAL NAME)
35    return()
36  endif()
37  if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS MINIMUM_VERSION)
38    message(FATAL_ERROR "Host ${NICE_NAME} version must be at least ${MINIMUM_VERSION}, your version is ${CMAKE_CXX_COMPILER_VERSION}.")
39  elseif(CMAKE_CXX_COMPILER_VERSION VERSION_LESS SOFT_ERROR_VERSION)
40    if(LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN)
41      message(WARNING "Host ${NICE_NAME} version should be at least ${SOFT_ERROR_VERSION} because LLVM will soon use new C++ features which your toolchain version doesn't support. Your version is ${CMAKE_CXX_COMPILER_VERSION}. Ignoring because you've set LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN, but very soon your toolchain won't be supported.")
42    else()
43      message(FATAL_ERROR "Host ${NICE_NAME} version should be at least ${SOFT_ERROR_VERSION} because LLVM will soon use new C++ features which your toolchain version doesn't support. Your version is ${CMAKE_CXX_COMPILER_VERSION}. You can temporarily opt out using LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN, but very soon your toolchain won't be supported.")
44    endif()
45  endif()
46endfunction(check_compiler_version)
47
48check_compiler_version("GNU" "GCC" ${GCC_MIN} ${GCC_SOFT_ERROR})
49check_compiler_version("Clang" "Clang" ${CLANG_MIN} ${CLANG_SOFT_ERROR})
50check_compiler_version("AppleClang" "Apple Clang" ${APPLECLANG_MIN} ${APPLECLANG_SOFT_ERROR})
51check_compiler_version("MSVC" "Visual Studio" ${MSVC_MIN} ${MSVC_SOFT_ERROR})
52
53if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
54  if (CMAKE_CXX_SIMULATE_ID MATCHES "MSVC")
55    if (CMAKE_CXX_SIMULATE_VERSION VERSION_LESS MSVC_MIN)
56      message(FATAL_ERROR "Host Clang must have at least -fms-compatibility-version=${MSVC_MIN}, your version is ${CMAKE_CXX_SIMULATE_VERSION}.")
57    endif()
58    set(CLANG_CL 1)
59  elseif(NOT LLVM_ENABLE_LIBCXX)
60    # Test that we aren't using too old of a version of libstdc++.
61    set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
62    set(OLD_CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
63    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -std=c++0x")
64    # Test for libstdc++ version of at least 4.8 by checking for _ZNKSt17bad_function_call4whatEv.
65    # Note: We should check _GLIBCXX_RELEASE when possible (i.e., for GCC 7.1 and up).
66    check_cxx_source_compiles("
67#include <iosfwd>
68#if defined(__GLIBCXX__)
69#if __GLIBCXX__ < ${GCC_MIN_DATE}
70#error Unsupported libstdc++ version
71#endif
72#endif
73#if defined(__GLIBCXX__)
74extern const char _ZNKSt17bad_function_call4whatEv[];
75const char *chk = _ZNKSt17bad_function_call4whatEv;
76#else
77const char *chk = \"\";
78#endif
79int main() { ++chk; return 0; }
80"
81      LLVM_LIBSTDCXX_MIN)
82    if(NOT LLVM_LIBSTDCXX_MIN)
83      message(FATAL_ERROR "libstdc++ version must be at least ${GCC_MIN}.")
84    endif()
85    # Test for libstdc++ version of at least 5.1 by checking for std::iostream_category().
86    # Note: We should check _GLIBCXX_RELEASE when possible (i.e., for GCC 7.1 and up).
87    check_cxx_source_compiles("
88#include <iosfwd>
89#if defined(__GLIBCXX__)
90#if __GLIBCXX__ < ${GCC_SOFT_ERROR_DATE}
91#error Unsupported libstdc++ version
92#endif
93#endif
94#if defined(__GLIBCXX__)
95#include <ios>
96void foo(void) { (void) std::iostream_category(); }
97#endif
98int main() { return 0; }
99"
100      LLVM_LIBSTDCXX_SOFT_ERROR)
101    if(NOT LLVM_LIBSTDCXX_SOFT_ERROR)
102      if(LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN)
103        message(WARNING "libstdc++ version should be at least ${GCC_SOFT_ERROR} because LLVM will soon use new C++ features which your toolchain version doesn't support. Ignoring because you've set LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN, but very soon your toolchain won't be supported.")
104      else()
105        message(FATAL_ERROR "libstdc++ version should be at least ${GCC_SOFT_ERROR} because LLVM will soon use new C++ features which your toolchain version doesn't support. You can temporarily opt out using LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN, but very soon your toolchain won't be supported.")
106      endif()
107    endif()
108    set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
109    set(CMAKE_REQUIRED_LIBRARIES ${OLD_CMAKE_REQUIRED_LIBRARIES})
110  endif()
111endif()
112