diff --git a/cmake/modules/CheckAtomic.cmake b/cmake/modules/CheckAtomic.cmake new file mode 100644 index 000000000..c045e30b2 --- /dev/null +++ b/cmake/modules/CheckAtomic.cmake @@ -0,0 +1,106 @@ +# atomic builtins are required for threading support. + +INCLUDE(CheckCXXSourceCompiles) +INCLUDE(CheckLibraryExists) + +# Sometimes linking against libatomic is required for atomic ops, if +# the platform doesn't support lock-free atomics. + +function(check_working_cxx_atomics varname) + set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS}) + set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -std=c++11") + CHECK_CXX_SOURCE_COMPILES(" +#include +std::atomic x; +int main() { + return x; +} +" ${varname}) + set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS}) +endfunction(check_working_cxx_atomics) + +function(check_working_cxx_atomics64 varname) + set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS}) + set(CMAKE_REQUIRED_FLAGS "-std=c++11 ${CMAKE_REQUIRED_FLAGS}") + CHECK_CXX_SOURCE_COMPILES(" +#include +#include +std::atomic x (0); +int main() { + uint64_t i = x.load(std::memory_order_relaxed); + return 0; +} +" ${varname}) + set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS}) +endfunction(check_working_cxx_atomics64) + + +# This isn't necessary on MSVC, so avoid command-line switch annoyance +# by only running on GCC-like hosts. +if (LLVM_COMPILER_IS_GCC_COMPATIBLE) + # First check if atomics work without the library. + check_working_cxx_atomics(HAVE_CXX_ATOMICS_WITHOUT_LIB) + # If not, check if the library exists, and atomics work with it. + if(NOT HAVE_CXX_ATOMICS_WITHOUT_LIB) + check_library_exists(atomic __atomic_fetch_add_4 "" HAVE_LIBATOMIC) + if( HAVE_LIBATOMIC ) + list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic") + check_working_cxx_atomics(HAVE_CXX_ATOMICS_WITH_LIB) + if (NOT HAVE_CXX_ATOMICS_WITH_LIB) + message(FATAL_ERROR "Host compiler must support std::atomic!") + endif() + else() + message(FATAL_ERROR "Host compiler appears to require libatomic, but cannot find it.") + endif() + endif() +endif() + +# Check for 64 bit atomic operations. +if(MSVC) + set(HAVE_CXX_ATOMICS64_WITHOUT_LIB True) +else() + check_working_cxx_atomics64(HAVE_CXX_ATOMICS64_WITHOUT_LIB) +endif() + +# If not, check if the library exists, and atomics work with it. +if(NOT HAVE_CXX_ATOMICS64_WITHOUT_LIB) + check_library_exists(atomic __atomic_load_8 "" HAVE_CXX_LIBATOMICS64) + if(HAVE_CXX_LIBATOMICS64) + list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic") + check_working_cxx_atomics64(HAVE_CXX_ATOMICS64_WITH_LIB) + if (NOT HAVE_CXX_ATOMICS64_WITH_LIB) + message(FATAL_ERROR "Host compiler must support 64-bit std::atomic!") + endif() + else() + message(FATAL_ERROR "Host compiler appears to require libatomic for 64-bit operations, but cannot find it.") + endif() +endif() + +## TODO: This define is only used for the legacy atomic operations in +## llvm's Atomic.h, which should be replaced. Other code simply +## assumes C++11 works. +CHECK_CXX_SOURCE_COMPILES(" +#ifdef _MSC_VER +#include +#endif +int main() { +#ifdef _MSC_VER + volatile LONG val = 1; + MemoryBarrier(); + InterlockedCompareExchange(&val, 0, 1); + InterlockedIncrement(&val); + InterlockedDecrement(&val); +#else + volatile unsigned long val = 1; + __sync_synchronize(); + __sync_val_compare_and_swap(&val, 1, 0); + __sync_add_and_fetch(&val, 1); + __sync_sub_and_fetch(&val, 1); +#endif + return 0; + } +" LLVM_HAS_ATOMICS) + +if( NOT LLVM_HAS_ATOMICS ) + message(STATUS "Warning: LLVM will be built thread-unsafe because atomic builtins are missing") +endif() \ No newline at end of file diff --git a/src/libslic3r/CMakeLists.txt b/src/libslic3r/CMakeLists.txt index d01c01ec2..e24880ca6 100644 --- a/src/libslic3r/CMakeLists.txt +++ b/src/libslic3r/CMakeLists.txt @@ -265,8 +265,11 @@ target_link_libraries(libslic3r ${CMAKE_DL_LIBS} ) -if (NOT MSVC) - target_link_libraries(libslic3r atomic) # no cmake magic for this... +include(CheckAtomic) + +check_working_cxx_atomics(HAS_ATOMIC) +if (NOT HAS_ATOMIC) + target_link_libraries(libslic3r atomic) endif() if (TARGET OpenVDB::openvdb)