[cmake][modules] FindAtomic update to target usage

1 files changed, 33 insertions, 42 deletions

diff --git a/cmake/modules/FindAtomic.cmake b/cmake/modules/FindAtomic.cmake
index 8ea3c815d7..91e0b39c13 100644
--- a/cmake/modules/FindAtomic.cmake
+++ b/cmake/modules/FindAtomic.cmake
@@ -3,54 +3,45 @@
 # -----
 # Finds the ATOMIC library
 #
-# This will define the following variables::
+# This will define the following target:
 #
-# ATOMIC_FOUND - system has ATOMIC
-# ATOMIC_LIBRARIES - the ATOMIC libraries
-#
-# and the following imported targets::
-#
-#   ATOMIC::ATOMIC    - The ATOMIC library
-
+#   ${APP_NAME_LC}::ATOMIC    - The ATOMIC library
 
-include(CheckCXXSourceCompiles)
+if(NOT TARGET ${APP_NAME_LC}::${CMAKE_FIND_PACKAGE_NAME})
+  include(CheckCXXSourceCompiles)
+  include(FindPackageMessage)
 
-set(atomic_code
-    "
-     #include <atomic>
-     #include <cstdint>
-     std::atomic<uint8_t> n8 (0); // riscv64
-     std::atomic<uint64_t> n64 (0); // armel, mipsel, powerpc
-     int main() {
-       ++n8;
-       ++n64;
-       return 0;
-     }")
+  set(atomic_code
+      "
+       #include <atomic>
+       #include <cstdint>
+       std::atomic<uint8_t> n8 (0); // riscv64
+       std::atomic<uint64_t> n64 (0); // armel, mipsel, powerpc
+       int main() {
+         ++n8;
+         ++n64;
+         return 0;
+       }")
 
-check_cxx_source_compiles("${atomic_code}" ATOMIC_LOCK_FREE_INSTRUCTIONS)
+  check_cxx_source_compiles("${atomic_code}" ATOMIC_LOCK_FREE_INSTRUCTIONS)
 
-if(ATOMIC_LOCK_FREE_INSTRUCTIONS)
-  set(ATOMIC_FOUND TRUE)
-  set(ATOMIC_LIBRARIES)
-else()
-  set(CMAKE_REQUIRED_LIBRARIES "-latomic")
-  check_cxx_source_compiles("${atomic_code}" ATOMIC_IN_LIBRARY)
-  set(CMAKE_REQUIRED_LIBRARIES)
-  if(ATOMIC_IN_LIBRARY)
-    set(ATOMIC_LIBRARY atomic)
-    include(FindPackageHandleStandardArgs)
-    find_package_handle_standard_args(Atomic DEFAULT_MSG ATOMIC_LIBRARY)
-    set(ATOMIC_LIBRARIES ${ATOMIC_LIBRARY})
-    if(NOT TARGET ATOMIC::ATOMIC)
-      add_library(ATOMIC::ATOMIC UNKNOWN IMPORTED)
-      set_target_properties(ATOMIC::ATOMIC PROPERTIES
-	      IMPORTED_LOCATION "${ATOMIC_LIBRARY}")
-    endif()
-    unset(ATOMIC_LIBRARY)
+  if(ATOMIC_LOCK_FREE_INSTRUCTIONS)
+    find_package_message(Atomic "Found Atomic: Lock Free" "")
   else()
-    if(Atomic_FIND_REQUIRED)
-      message(FATAL_ERROR "Neither lock free instructions nor -latomic found.")
+    set(CMAKE_REQUIRED_LIBRARIES "-latomic")
+    check_cxx_source_compiles("${atomic_code}" ATOMIC_IN_LIBRARY)
+    set(CMAKE_REQUIRED_LIBRARIES)
+    if(ATOMIC_IN_LIBRARY)
+      find_package_message(Atomic "Found Atomic library: -latomic" "")
+
+      add_library(${APP_NAME_LC}::${CMAKE_FIND_PACKAGE_NAME} UNKNOWN IMPORTED)
+      set_target_properties(${APP_NAME_LC}::${CMAKE_FIND_PACKAGE_NAME} PROPERTIES
+                                                                       IMPORTED_LOCATION "-latomic")
+    else()
+      if(Atomic_FIND_REQUIRED)
+        message(FATAL_ERROR "Neither lock free instructions nor -latomic found.")
+      endif()
     endif()
   endif()
+  unset(atomic_code)
 endif()
-unset(atomic_code)