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} ${MSVC_SOFT_ERROR})
52
53# See https://developercommunity.visualstudio.com/content/problem/845933/miscompile-boolean-condition-deduced-to-be-always.html
54# and thread "[llvm-dev] Longstanding failing tests - clang-tidy, MachO, Polly"
55# on llvm-dev Jan 21-23 2020.
56if ((${CMAKE_CXX_COMPILER_ID} STREQUAL MSVC) AND
57    (19.24 VERSION_LESS_EQUAL ${CMAKE_CXX_COMPILER_VERSION}) AND
58    (${CMAKE_CXX_COMPILER_VERSION} VERSION_LESS 19.25))
59  if(LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN)
60    message(WARNING "Host Visual Studio version 16.4 is known to miscompile part of LLVM")
61  else()
62    message(FATAL_ERROR "Host Visual Studio version 16.4 is known to miscompile part of LLVM, please use clang-cl or upgrade to 16.5 or above (use -DLLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN=ON to ignore)")
63  endif()
64endif()
65
66
67if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
68  if (CMAKE_CXX_SIMULATE_ID MATCHES "MSVC")
69    if (CMAKE_CXX_SIMULATE_VERSION VERSION_LESS MSVC_MIN)
70      message(FATAL_ERROR "Host Clang must have at least -fms-compatibility-version=${MSVC_MIN}, your version is ${CMAKE_CXX_SIMULATE_VERSION}.")
71    endif()
72    set(CLANG_CL 1)
73  elseif(NOT LLVM_ENABLE_LIBCXX)
74    # Test that we aren't using too old of a version of libstdc++.
75    set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
76    set(OLD_CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
77    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -std=c++0x")
78    # Test for libstdc++ version of at least 4.8 by checking for _ZNKSt17bad_function_call4whatEv.
79    # Note: We should check _GLIBCXX_RELEASE when possible (i.e., for GCC 7.1 and up).
80    check_cxx_source_compiles("
81#include <iosfwd>
82#if defined(__GLIBCXX__)
83#if __GLIBCXX__ < ${GCC_MIN_DATE}
84#error Unsupported libstdc++ version
85#endif
86#endif
87#if defined(__GLIBCXX__)
88extern const char _ZNKSt17bad_function_call4whatEv[];
89const char *chk = _ZNKSt17bad_function_call4whatEv;
90#else
91const char *chk = \"\";
92#endif
93int main() { ++chk; return 0; }
94"
95      LLVM_LIBSTDCXX_MIN)
96    if(NOT LLVM_LIBSTDCXX_MIN)
97      message(FATAL_ERROR "libstdc++ version must be at least ${GCC_MIN}.")
98    endif()
99    # Test for libstdc++ version of at least 5.1 by checking for std::iostream_category().
100    # Note: We should check _GLIBCXX_RELEASE when possible (i.e., for GCC 7.1 and up).
101    check_cxx_source_compiles("
102#include <iosfwd>
103#if defined(__GLIBCXX__)
104#if __GLIBCXX__ < ${GCC_SOFT_ERROR_DATE}
105#error Unsupported libstdc++ version
106#endif
107#endif
108#if defined(__GLIBCXX__)
109#include <ios>
110void foo(void) { (void) std::iostream_category(); }
111#endif
112int main() { return 0; }
113"
114      LLVM_LIBSTDCXX_SOFT_ERROR)
115    if(NOT LLVM_LIBSTDCXX_SOFT_ERROR)
116      if(LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN)
117        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.")
118      else()
119        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.")
120      endif()
121    endif()
122    set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
123    set(CMAKE_REQUIRED_LIBRARIES ${OLD_CMAKE_REQUIRED_LIBRARIES})
124  endif()
125endif()
126