Add CXX_FLAGS_BY_COMPILER_FRONTEND function

compiler.cmake

@@ -19,51 +19,140 @@ macro(_SETUP_PROJECT_WARNINGS)
   # -Wmissing-declarations is disabled for now as older GCC version does not
   # support it but CMake doest not check for the flag acceptance correctly.
 
-  if(UNIX)
-    set(FLAGS
-        -pedantic
-        -Wno-long-long
-        -Wall
-        -Wextra
-        -Wcast-align
-        -Wcast-qual
-        -Wformat
-        -Wwrite-strings
-        -Wconversion)
-    foreach(FLAG ${FLAGS})
-      check_cxx_compiler_flag(${FLAG} R${FLAG})
-      if(${R${FLAG}})
-        set(WARNING_CXX_FLAGS "${WARNING_CXX_FLAGS} ${FLAG}")
-      endif(${R${FLAG}})
-    endforeach(FLAG ${FLAGS})
-
-    if(NOT DEFINED CXX_DISABLE_WERROR)
-      set(WARNING_CXX_FLAGS "-Werror ${WARNING_CXX_FLAGS}")
-    endif(NOT DEFINED CXX_DISABLE_WERROR)
-  endif(UNIX)
+  set(GNU_FLAGS
+      -pedantic
+      -Wno-long-long
+      -Wall
+      -Wextra
+      -Wcast-align
+      -Wcast-qual
+      -Wformat
+      -Wwrite-strings
+      -Wconversion)
+  if(NOT DEFINED CXX_DISABLE_WERROR)
+    list(APPEND GNU_FLAGS -Werror)
+  endif(NOT DEFINED CXX_DISABLE_WERROR)
 
   # For win32 systems, it is impossible to use Wall, especially with boost,
   # which is way too verbose The default levels (W3/W4) are enough The next
   # macro remove warnings on deprecations due to stl.
-  if(MSVC)
-    set(WARNING_CXX_FLAGS "-D_SCL_SECURE_NO_WARNINGS -D_CRT_SECURE_NO_WARNINGS")
-    set(WARNING_CXX_FLAGS "${WARNING_CXX_FLAGS} -D_CRT_SECURE_NO_DEPRECATE")
-    # -- The following warnings are removed to highlight the output C4101 The
-    # local variable is never used removed since happens frequently in headers.
-    set(WARNING_CXX_FLAGS "${WARNING_CXX_FLAGS} /wd4101")
-    # C4250 'class1' : inherits 'class2::member' via dominance
-    set(WARNING_CXX_FLAGS "${WARNING_CXX_FLAGS} /wd4250")
-    # C4251 class 'type' needs to have dll-interface to be used by clients of
-    # class 'type2' ~ in practice, raised by the classes that have non-dll
-    # attribute (such as std::vector)
-    set(WARNING_CXX_FLAGS "${WARNING_CXX_FLAGS} /wd4251")
-    # C4275 non - DLL-interface used as base for DLL-interface
-    set(WARNING_CXX_FLAGS "${WARNING_CXX_FLAGS} /wd4275")
-    # C4355 "this" used in base member initializer list
-    set(WARNING_CXX_FLAGS "${WARNING_CXX_FLAGS} /wd4355")
-  endif()
+  set(MSVC_FLAGS
+      -D_SCL_SECURE_NO_WARNINGS
+      -D_CRT_SECURE_NO_WARNINGS
+      -D_CRT_SECURE_NO_DEPRECATE
+      # -- The following warnings are removed to highlight the output C4101 The
+      # local variable is never used removed since happens frequently in
+      # headers.
+      /wd4101
+      # C4250 'class1' : inherits 'class2::member' via dominance
+      /wd4250
+      # C4251 class 'type' needs to have dll-interface to be used by clients of
+      # class 'type2' ~ in practice, raised by the classes that have non-dll
+      # attribute (such as std::vector)
+      /wd4251
+      # C4275 non - DLL-interface used as base for DLL-interface
+      /wd4275
+      # C4355 "this" used in base member initializer list
+      /wd4355)
+
+  cxx_flags_by_compiler_frontend(
+    GNU
+    ${GNU_FLAGS}
+    MSVC
+    ${MSVC_FLAGS}
+    OUTPUT
+    WARNING_CXX_FLAGS_LIST
+    FILTER)
+  string(REPLACE ";" " " WARNING_CXX_FLAGS "${WARNING_CXX_FLAGS_LIST}")
 
   set(CMAKE_CXX_FLAGS "${WARNING_CXX_FLAGS} ${CMAKE_CXX_FLAGS}")
 
   list(APPEND LOGGING_WATCHED_VARIABLES WARNING_CXX_FLAGS)
 endmacro(_SETUP_PROJECT_WARNINGS)
+
+#[=======================================================================[.rst:
+.. command:: CXX_FLAGS_BY_COMPILER_FRONTEND(<GCC   [<flags1>...]>
+                                            <MSVC  [<flags1>...]>
+                                            OUTPUT flags
+                                            <FILTER>)
+
+Detect the compiler frontend (the command line interface) and output the
+corresponding ``CXX_FLAGS``.
+
+The following arguments allow to specify ``CXX_FLAGS`` for a compiler
+frontend:
+
+:param GNU: List of flags for GNU compiler frontend (Gcc, G++)
+:param MSVC: List of flags for MSVC compiler frontend (MSVC, ClangCl)
+
+Detected compiler frontend flags are then outputed in the ``OUTPUT``
+parameter.
+
+Optional ``FILTER`` parameter filter outputed flags with check_cxx_compiler_flag.
+
+.. warning:: When ``FILTER`` option is activated, definition should by passed with
+-D prefix to be valid compiler parameter.
+
+Example
+^^^^^^^
+
+.. code-block:: cmake
+  CXX_FLAGS_BY_COMPILER_FRONTEND(
+    GNU -Wno-conversion -Wno-comment -Wno-self-assign-overloaded
+    MSVC  "/bigobj"
+    OUTPUT COMPLIE_OPTIONS
+    FILTER)
+#]=======================================================================]
+
+function(CXX_FLAGS_BY_COMPILER_FRONTEND)
+  set(options FILTER)
+  set(oneValueArgs OUTPUT)
+  set(multiValueArgs GNU MSVC)
+  cmake_parse_arguments(ARGS "${options}" "${oneValueArgs}" "${multiValueArgs}"
+                        ${ARGN})
+
+  # Before CMake 3.14, the CMAKE_CXX_COMPILER_FRONTEND_VARIANT doesn't exists.
+  # Before CMake 3.26, when CMAKE_CXX_COMPILER_ID is set to GNU, MSVC or
+  # AppleClang, CMAKE_CXX_COMPILER_FRONTEND_VARIANT doesn't exists either
+  if(CMAKE_CXX_COMPILER_FRONTEND_VARIANT)
+    if(CMAKE_CXX_COMPILER_FRONTEND_VARIANT STREQUAL "GNU")
+      set(FLAGS ${ARGS_GNU})
+    elseif(CMAKE_CXX_COMPILER_FRONTEND_VARIANT STREQUAL "MSVC")
+      set(FLAGS ${ARGS_MSVC})
+    else()
+      message(
+        WARNING "Unknown compiler frontend for '${CMAKE_CXX_COMPILER_ID}' "
+                "with frontend '${CMAKE_CXX_COMPILER_FRONTEND_VARIANT}'\n"
+                "No flags outputed")
+    endif()
+  else()
+    if(CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND CMAKE_CXX_SIMULATE_ID MATCHES
+                                                 "MSVC")
+      set(FLAGS ${ARGS_MSVC})
+    elseif(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
+      set(FLAGS ${ARGS_MSVC})
+    elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang|GNU")
+      set(FLAGS ${ARGS_GNU})
+    else()
+      message(
+        WARNING "Unknown compiler frontend for '${CMAKE_CXX_COMPILER_ID}' "
+                "with simulated ID '${CMAKE_CXX_SIMULATED_ID}'\n"
+                "No flags outputed")
+    endif()
+  endif()
+
+  if(ARGS_FILTER)
+    foreach(FLAG ${FLAGS})
+      check_cxx_compiler_flag(${FLAG} res_${FLAG})
+      if(${res_${FLAG}})
+        list(APPEND FILTERED_FLAGS ${FLAG})
+      endif()
+    endforeach()
+  else()
+    set(FILTERED_FLAGS ${FLAGS})
+  endif()
+
+  set(${ARGS_OUTPUT}
+      ${FILTERED_FLAGS}
+      PARENT_SCOPE)
+endfunction()