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 7.4)
8set(GCC_SOFT_ERROR 7.4)
9set(CLANG_MIN 5.0)
10set(CLANG_SOFT_ERROR 5.0)
11set(APPLECLANG_MIN 10.0)
12set(APPLECLANG_SOFT_ERROR 10.0)
13
14# https://en.wikipedia.org/wiki/Microsoft_Visual_C#Internal_version_numbering
15# _MSC_VER == 1927 MSVC++ 14.27 Visual Studio 2019 Version 16.7
16set(MSVC_MIN 19.27)
17set(MSVC_SOFT_ERROR 19.27)
18
19set(LIBSTDCXX_MIN 7)
20set(LIBSTDCXX_SOFT_ERROR 7)
21
22
23if(DEFINED LLVM_COMPILER_CHECKED)
24  return()
25endif()
26set(LLVM_COMPILER_CHECKED ON)
27
28if(LLVM_FORCE_USE_OLD_TOOLCHAIN)
29  return()
30endif()
31
32function(check_compiler_version NAME NICE_NAME MINIMUM_VERSION SOFT_ERROR_VERSION)
33  if(NOT CMAKE_CXX_COMPILER_ID STREQUAL NAME)
34    return()
35  endif()
36  if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS MINIMUM_VERSION)
37    message(FATAL_ERROR "Host ${NICE_NAME} version must be at least ${MINIMUM_VERSION}, your version is ${CMAKE_CXX_COMPILER_VERSION}.")
38  elseif(CMAKE_CXX_COMPILER_VERSION VERSION_LESS SOFT_ERROR_VERSION)
39    if(LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN)
40      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.")
41    else()
42      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.")
43    endif()
44  endif()
45endfunction(check_compiler_version)
46
47check_compiler_version("GNU" "GCC" ${GCC_MIN} ${GCC_SOFT_ERROR})
48check_compiler_version("Clang" "Clang" ${CLANG_MIN} ${CLANG_SOFT_ERROR})
49check_compiler_version("AppleClang" "Apple Clang" ${APPLECLANG_MIN} ${APPLECLANG_SOFT_ERROR})
50check_compiler_version("MSVC" "Visual Studio" ${MSVC_MIN} ${MSVC_SOFT_ERROR})
51
52# See https://developercommunity.visualstudio.com/content/problem/845933/miscompile-boolean-condition-deduced-to-be-always.html
53# and thread "[llvm-dev] Longstanding failing tests - clang-tidy, MachO, Polly"
54# on llvm-dev Jan 21-23 2020.
55if ((${CMAKE_CXX_COMPILER_ID} STREQUAL MSVC) AND
56    (19.24 VERSION_LESS_EQUAL ${CMAKE_CXX_COMPILER_VERSION}) AND
57    (${CMAKE_CXX_COMPILER_VERSION} VERSION_LESS 19.25))
58  if(LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN)
59    message(WARNING "Host Visual Studio version 16.4 is known to miscompile part of LLVM")
60  else()
61    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)")
62  endif()
63endif()
64
65
66if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
67  if (CMAKE_CXX_SIMULATE_ID MATCHES "MSVC")
68    if (CMAKE_CXX_SIMULATE_VERSION VERSION_LESS MSVC_MIN)
69      message(FATAL_ERROR "Host Clang must have at least -fms-compatibility-version=${MSVC_MIN}, your version is ${CMAKE_CXX_SIMULATE_VERSION}.")
70    endif()
71    set(CLANG_CL 1)
72  elseif(NOT LLVM_ENABLE_LIBCXX)
73    # Test that we aren't using too old of a version of libstdc++.
74    set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
75    set(OLD_CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
76    set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -std=c++0x")
77    check_cxx_source_compiles("
78#include <iosfwd>
79#if defined(__GLIBCXX__)
80#if !defined(_GLIBCXX_RELEASE) || _GLIBCXX_RELEASE < ${LIBSTDCXX_MIN}
81#error Unsupported libstdc++ version
82#endif
83#endif
84int main() { return 0; }
85"
86      LLVM_LIBSTDCXX_MIN)
87    if(NOT LLVM_LIBSTDCXX_MIN)
88      message(FATAL_ERROR "libstdc++ version must be at least ${GCC_MIN}.")
89    endif()
90    check_cxx_source_compiles("
91#include <iosfwd>
92#if defined(__GLIBCXX__)
93#if !defined(_GLIBCXX_RELEASE) || _GLIBCXX_RELEASE < ${LIBSTDCXX_SOFT_ERROR}
94#error Unsupported libstdc++ version
95#endif
96#endif
97int main() { return 0; }
98"
99      LLVM_LIBSTDCXX_SOFT_ERROR)
100    if(NOT LLVM_LIBSTDCXX_SOFT_ERROR)
101      if(LLVM_TEMPORARILY_ALLOW_OLD_TOOLCHAIN)
102        message(WARNING "libstdc++ version should be at least ${LIBSTDCXX_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.")
103      else()
104        message(FATAL_ERROR "libstdc++ version should be at least ${LIBSTDCXX_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.")
105      endif()
106    endif()
107    set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
108    set(CMAKE_REQUIRED_LIBRARIES ${OLD_CMAKE_REQUIRED_LIBRARIES})
109  endif()
110endif()
111