diff options
| -rw-r--r-- | CMakeLists.txt | 24 | ||||
| -rw-r--r-- | build_files/cmake/macros.cmake | 10 |
2 files changed, 31 insertions, 3 deletions
diff --git a/CMakeLists.txt b/CMakeLists.txt index a950fc5d893..1539a55d74d 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -478,9 +478,19 @@ if(WIN32) endif() # Experimental support of C11 and C++11 -option(WITH_C11 "Build with C11 standard enabled, for development use only!" OFF) +# +# We default options to whatever default standard in the current compiler. +if(CMAKE_COMPILER_IS_GNUCC AND (NOT "${CMAKE_C_COMPILER_VERSION}" VERSION_LESS "6.0") AND (NOT WITH_CXX11)) + set(_c11_init ON) + set(_cxx11_init ON) +else() + set(_c11_init OFF) + set(_cxx11_init OFF) +endif() + +option(WITH_C11 "Build with C11 standard enabled, for development use only!" ${_c11_init}) mark_as_advanced(WITH_C11) -option(WITH_CXX11 "Build with C++11 standard enabled, for development use only!" OFF) +option(WITH_CXX11 "Build with C++11 standard enabled, for development use only!" ${_cxx11_init}) mark_as_advanced(WITH_CXX11) # Dependency graph @@ -3024,12 +3034,22 @@ endif() if(WITH_CXX11) if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_C_COMPILER_ID MATCHES "Clang") + # TODO(sergey): Do we want c++11 or gnu-c++11 here? set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11") elseif(MSVC12) # Nothing special is needed, C++11 features are available by default. else() message(FATAL_ERROR "Compiler ${CMAKE_C_COMPILER_ID} is not supported for C++11 build yet") endif() +else() + # GCC-6 switched to C++11 by default, which would break linking with existing libraries + # by default. So we explicitly disable C++11 for a new GCC so no linking issues happens. + if(CMAKE_COMPILER_IS_GNUCC AND (NOT "${CMAKE_C_COMPILER_VERSION}" VERSION_LESS "6.0")) + set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++98") + # We also disable any of C++11 ABI from usage, so we wouldn't even try to + # link to stuff from std::__cxx11 namespace. + add_definitions("-D_GLIBCXX_USE_CXX11_ABI=0") + endif() endif() # Visual Studio has all standards it supports available by default diff --git a/build_files/cmake/macros.cmake b/build_files/cmake/macros.cmake index 239371c227c..08d26e55ed4 100644 --- a/build_files/cmake/macros.cmake +++ b/build_files/cmake/macros.cmake @@ -803,7 +803,15 @@ macro(TEST_UNORDERED_MAP_SUPPORT) # UNORDERED_MAP_NAMESPACE, namespace for unordered_map, if found include(CheckIncludeFileCXX) - CHECK_INCLUDE_FILE_CXX("unordered_map" HAVE_STD_UNORDERED_MAP_HEADER) + + # Workaround for newer GCC (6.x+) where C++11 was enabled by default, which lead us + # to a situation when there is <unordered_map> include but which can't be used uless + # C++11 is enabled. + if(CMAKE_COMPILER_IS_GNUCC AND (NOT "${CMAKE_C_COMPILER_VERSION}" VERSION_LESS "6.0") AND (NOT WITH_CXX11)) + set(HAVE_STD_UNORDERED_MAP_HEADER False) + else() + CHECK_INCLUDE_FILE_CXX("unordered_map" HAVE_STD_UNORDERED_MAP_HEADER) + endif() if(HAVE_STD_UNORDERED_MAP_HEADER) # Even so we've found unordered_map header file it doesn't # mean unordered_map and unordered_set will be declared in |