refs #14584 - separated handling of Clang and AppleClang in CMake

Author: firewave

cmake/compilerCheck.cmake

@@ -2,12 +2,16 @@ if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.1)
         message(ERROR "GCC >= 5.1 required - detected ${CMAKE_CXX_COMPILER_VERSION} not supported")
     endif()
-elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
     if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.5)
         message(ERROR "Clang >= 3.5 required - detected ${CMAKE_CXX_COMPILER_VERSION} not supported")
     endif()
+elseif(CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
+    # TODO: AppleClang versions do not align with Clang versions - add check for proper version
 elseif(MSVC)
     if(MSVC_VERSION VERSION_LESS 1900)
         message(ERROR "Visual Studio >= 2015 (19.0) required - detected ${MSVC_VERSION} not supported")
     endif()
+else()
+    message(WARNING "Unknown compiler ${CMAKE_CXX_COMPILER_ID}")
 endif()

cmake/compilerDefinitions.cmake

@@ -8,26 +8,29 @@ if(MSVC)
     add_definitions(-DWIN32_LEAN_MEAN)
 endif()
 
-# TODO: this should probably apply to the compiler and not the platform - I think it is only "broken" with MinGW
-# TODO: AppleClang only has libc++
-# TODO: what about clang-cl and native Win32 clang?
-if(CPPCHK_GLIBCXX_DEBUG AND UNIX AND CMAKE_BUILD_TYPE STREQUAL "Debug")
-    if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
-        if(USE_LIBCXX)
-            if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 18)
-                add_definitions(-D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_DEBUG)
-            else()
-                add_definitions(-D_LIBCPP_ENABLE_ASSERTIONS=1)
-            endif()
-            # TODO: also add _LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS?
+# libstdc++-specific flags
+if(CMAKE_CXX_COMPILER_ID MATCHES "GNU" OR (NOT USE_LIBCXX AND CMAKE_CXX_COMPILER_ID MATCHES "Clang"))
+    if(CPPCHK_GLIBCXX_DEBUG AND CMAKE_BUILD_TYPE STREQUAL "Debug")
+        add_definitions(-D_GLIBCXX_DEBUG)
+    endif()
+endif()
+
+# TODO: what about clang-cl?
+# libc++-specific flags - AppleClang only has libc++
+if ((USE_LIBCXX AND CMAKE_CXX_COMPILER_ID MATCHES "Clang") OR CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
+    if(CPPCHK_GLIBCXX_DEBUG AND CMAKE_BUILD_TYPE STREQUAL "Debug")
+        # TODO: AppleClang versions do not align with Clang versions - add check for proper version
+        if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 18)
+            add_definitions(-D_LIBCPP_HARDENING_MODE=_LIBCPP_HARDENING_MODE_DEBUG)
+        else()
+            add_definitions(-D_LIBCPP_ENABLE_ASSERTIONS=1)
         endif()
+        # TODO: also add _LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS?
     else()
         # TODO: check if this can be enabled again for Clang - also done in Makefile
         add_definitions(-D_GLIBCXX_DEBUG)
     endif()
-endif()
 
-if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND USE_LIBCXX)
     add_definitions(-D_LIBCPP_REMOVE_TRANSITIVE_INCLUDES)
 endif()
 

cmake/options.cmake

@@ -116,6 +116,10 @@ if (NOT USE_BOOST AND USE_BOOST_INT128)
 endif()
 option(USE_LIBCXX           "Use libc++ instead of libstdc++"                               OFF)
 
+if(USE_LIBCXX AND NOT CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+    message(FATAL_ERROR "libc++ can only be used with a Clang-based compiler")
+endif()
+
 option(NO_UNIX_SIGNAL_HANDLING "Disable usage of Unix Signal Handling"                      OFF)
 option(NO_UNIX_BACKTRACE_SUPPORT "Disable usage of Unix Backtrace support"                  OFF)
 option(NO_WINDOWS_SEH       "Disable usage of Windows SEH"                                  OFF)

lib/config.h

@@ -96,6 +96,7 @@
 #  define UNUSED
 #endif
 
+// TODO: AppleClang versions do not align with Clang versions - add check for proper version
 // warn_unused
 #if __has_cpp_attribute (gnu::warn_unused) || \
     (defined(__clang__) && (__clang_major__ >= 15))
@@ -115,6 +116,7 @@
 #  define DEPRECATED
 #endif
 
+// TODO: AppleClang versions do not align with Clang versions - add check for proper version
 // returns_nonnull
 #if __has_cpp_attribute (gnu::returns_nonnull)
 #  define RET_NONNULL [[gnu::returns_nonnull]]