vasilito
cf12defd28
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent) Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
96 lines
3.2 KiB
CMake
96 lines
3.2 KiB
CMake
# SPDX-FileCopyrightText: 2003-2018 University of Illinois at Urbana-Champaign.
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#
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# SPDX-License-Identifier: BSD-3-Clause
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#[=======================================================================[.rst:
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CheckAtomic
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-----------
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Check if the compiler supports std:atomic out of the box or if libatomic is
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needed for atomic support. If it is needed libatomicis added to
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``CMAKE_REQUIRED_LIBRARIES``. So after running CheckAtomic you can use
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std:atomic.
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Since 5.75.0.
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#]=======================================================================]
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include(CheckCXXSourceCompiles)
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include(CheckLibraryExists)
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# Sometimes linking against libatomic is required for atomic ops, if
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# the platform doesn't support lock-free atomics.
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function(check_working_cxx_atomics varname)
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set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
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set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -std=c++11")
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check_cxx_source_compiles("
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#include <atomic>
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std::atomic<int> x;
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std::atomic<short> y;
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std::atomic<char> z;
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int main() {
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++z;
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++y;
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return ++x;
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}
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" ${varname})
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set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
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endfunction()
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function(check_working_cxx_atomics64 varname)
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set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
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set(CMAKE_REQUIRED_FLAGS "-std=c++11 ${CMAKE_REQUIRED_FLAGS}")
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check_cxx_source_compiles("
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#include <atomic>
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#include <cstdint>
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std::atomic<uint64_t> x (0);
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int main() {
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uint64_t i = x.load(std::memory_order_relaxed);
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return 0;
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}
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" ${varname})
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set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
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endfunction()
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# Check for (non-64-bit) atomic operations.
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if(MSVC)
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set(HAVE_CXX_ATOMICS_WITHOUT_LIB True)
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elseif(LLVM_COMPILER_IS_GCC_COMPATIBLE)
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# First check if atomics work without the library.
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check_working_cxx_atomics(HAVE_CXX_ATOMICS_WITHOUT_LIB)
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# If not, check if the library exists, and atomics work with it.
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if(NOT HAVE_CXX_ATOMICS_WITHOUT_LIB)
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check_library_exists(atomic __atomic_fetch_add_4 "" HAVE_LIBATOMIC)
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if(HAVE_LIBATOMIC)
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list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic")
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check_working_cxx_atomics(HAVE_CXX_ATOMICS_WITH_LIB)
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if (NOT HAVE_CXX_ATOMICS_WITH_LIB)
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message(FATAL_ERROR "Host compiler must support std::atomic!")
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endif()
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else()
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message(FATAL_ERROR "Host compiler appears to require libatomic, but cannot find it.")
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endif()
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endif()
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endif()
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# Check for 64 bit atomic operations.
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if(MSVC)
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set(HAVE_CXX_ATOMICS64_WITHOUT_LIB True)
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elseif(LLVM_COMPILER_IS_GCC_COMPATIBLE)
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# First check if atomics work without the library.
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check_working_cxx_atomics64(HAVE_CXX_ATOMICS64_WITHOUT_LIB)
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# If not, check if the library exists, and atomics work with it.
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if(NOT HAVE_CXX_ATOMICS64_WITHOUT_LIB)
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check_library_exists(atomic __atomic_load_8 "" HAVE_CXX_LIBATOMICS64)
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if(HAVE_CXX_LIBATOMICS64)
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list(APPEND CMAKE_REQUIRED_LIBRARIES "atomic")
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check_working_cxx_atomics64(HAVE_CXX_ATOMICS64_WITH_LIB)
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if (NOT HAVE_CXX_ATOMICS64_WITH_LIB)
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message(FATAL_ERROR "Host compiler must support 64-bit std::atomic!")
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endif()
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else()
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message(FATAL_ERROR "Host compiler appears to require libatomic for 64-bit operations, but cannot find it.")
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endif()
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endif()
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endif()
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