cmake/modules/FindAtomic.cmake

   1 #.rst:
   2 # FindAtomic
   3 # -----
   4 # Finds the ATOMIC library
   5 #
   6 # This will define the following target:
   7 #
   8 #   ${APP_NAME_LC}::ATOMIC    - The ATOMIC library
   9
  10 if(NOT TARGET ${APP_NAME_LC}::${CMAKE_FIND_PACKAGE_NAME})
  11   include(CheckCXXSourceCompiles)
  12   include(FindPackageMessage)
  13
  14   set(atomic_code
  15       "
  16        #include <atomic>
  17        #include <cstdint>
  18        std::atomic<uint8_t> n8 (0); // riscv64
  19        std::atomic<uint64_t> n64 (0); // armel, mipsel, powerpc
  20        int main() {
  21          ++n8;
  22          ++n64;
  23          return 0;
  24        }")
  25
  26   check_cxx_source_compiles("${atomic_code}" ATOMIC_LOCK_FREE_INSTRUCTIONS)
  27
  28   if(ATOMIC_LOCK_FREE_INSTRUCTIONS)
  29     find_package_message(Atomic "Found Atomic: Lock Free" "")
  30   else()
  31     set(CMAKE_REQUIRED_LIBRARIES "-latomic")
  32     check_cxx_source_compiles("${atomic_code}" ATOMIC_IN_LIBRARY)
  33     set(CMAKE_REQUIRED_LIBRARIES)
  34     if(ATOMIC_IN_LIBRARY)
  35       find_package_message(Atomic "Found Atomic library: -latomic" "")
  36
  37       add_library(${APP_NAME_LC}::${CMAKE_FIND_PACKAGE_NAME} UNKNOWN IMPORTED)
  38       set_target_properties(${APP_NAME_LC}::${CMAKE_FIND_PACKAGE_NAME} PROPERTIES
  39                                                                        IMPORTED_LOCATION "-latomic")
  40     else()
  41       if(Atomic_FIND_REQUIRED)
  42         message(FATAL_ERROR "Neither lock free instructions nor -latomic found.")
  43       endif()
  44     endif()
  45   endif()
  46   unset(atomic_code)
  47 endif()