llvm-mirror/cmake/modules/CheckCompilerVersion.cmake
Don Hinton 130f9a4a59 [cmake] Always respect existing CMAKE_REQUIRED_FLAGS when adding additional ones.
Summary:
Always respect existing CMAKE_REQUIRED_FLAGS when adding
additional ones.  This is important when cross compiling where
--sysroot and -target were already added.

In particular, this is needed when cross compiling from Darwin to
Linux, since --sysroot is required to find headers and libraries.

Cmake has a similar bug in check_include_file[_cxx] where
CMAKE_REQUIRED_LIBRARIES isn't passed, which causes
try_compile to fail.
(please see https://gitlab.kitware.com/cmake/cmake/merge_requests/1620)

Reviewers: compnerd, silvas, beanz, brad.king

Reviewed By: compnerd

Subscribers: mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D41568

llvm-svn: 321434
2017-12-25 01:23:09 +00:00

53 lines
2.2 KiB
CMake

# Check if the host compiler is new enough. LLVM requires at least GCC 4.8,
# MSVC 2015 (Update 3), or Clang 3.1.
include(CheckCXXSourceCompiles)
if(NOT DEFINED LLVM_COMPILER_CHECKED)
set(LLVM_COMPILER_CHECKED ON)
if(NOT LLVM_FORCE_USE_OLD_TOOLCHAIN)
if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.8)
message(FATAL_ERROR "Host GCC version must be at least 4.8!")
endif()
elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.1)
message(FATAL_ERROR "Host Clang version must be at least 3.1!")
endif()
if (CMAKE_CXX_SIMULATE_ID MATCHES "MSVC")
if (CMAKE_CXX_SIMULATE_VERSION VERSION_LESS 19.0)
message(FATAL_ERROR "Host Clang must have at least -fms-compatibility-version=19.0")
endif()
set(CLANG_CL 1)
elseif(NOT LLVM_ENABLE_LIBCXX)
# Otherwise, test that we aren't using too old of a version of libstdc++
# with the Clang compiler. This is tricky as there is no real way to
# check the version of libstdc++ directly. Instead we test for a known
# bug in libstdc++4.6 that is fixed in libstdc++4.7.
set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
set(OLD_CMAKE_REQUIRED_LIBRARIES ${CMAKE_REQUIRED_LIBRARIES})
set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -std=c++0x")
check_cxx_source_compiles("
#include <atomic>
std::atomic<float> x(0.0f);
int main() { return (float)x; }"
LLVM_NO_OLD_LIBSTDCXX)
if(NOT LLVM_NO_OLD_LIBSTDCXX)
message(FATAL_ERROR "Host Clang must be able to find libstdc++4.8 or newer!")
endif()
set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
set(CMAKE_REQUIRED_LIBRARIES ${OLD_CMAKE_REQUIRED_LIBRARIES})
endif()
elseif(CMAKE_CXX_COMPILER_ID MATCHES "MSVC")
if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 19.0)
message(FATAL_ERROR "Host Visual Studio must be at least 2015")
elseif(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 19.00.24213.1)
message(WARNING "Host Visual Studio should at least be 2015 Update 3 (MSVC 19.00.24213.1)"
" due to miscompiles from earlier versions")
endif()
endif()
endif()
endif()