#1602: use target_compile_options for enabling warnings

CMakeLists.txt

@@ -11,15 +11,17 @@ cmake_policy(SET CMP0082 NEW)
 
 get_directory_property(hasParent PARENT_DIRECTORY)
 
-include(cmake/turn_on_warnings.cmake)
-
 include(cmake/check_system_functions.cmake)
 
 set(VIRTUAL_TRANSPORT_LIBRARY vt CACHE INTERNAL "" FORCE )
 set(FCONTEXT_LIBRARY fcontext)
 
 # Set the local module path so custom cmake scripts can be located automatically
-set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/cmake-modules/")
+set(
+  CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH}
+  "${CMAKE_CURRENT_SOURCE_DIR}/cmake-modules/"
+  "${CMAKE_CURRENT_SOURCE_DIR}/cmake/"
+)
 
 # Try to find ccache to speed up compilation
 find_program(ccache_binary ccache)

cmake/turn_on_warnings.cmake

@@ -1,26 +1,25 @@
 include(CheckCXXCompilerFlag)
 
 function(enable_cxx_compiler_flag_if_supported flag)
-  string(FIND "${CMAKE_CXX_FLAGS}" "${flag}" flag_already_set)
-  if(flag_already_set EQUAL -1)
-    check_cxx_compiler_flag("${flag}" flag_supported)
-    if(flag_supported)
-      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${flag}" PARENT_SCOPE)
-    endif()
-    unset(flag_supported CACHE)
+  check_cxx_compiler_flag("${flag}" flag_supported)
+  if(flag_supported)
+    target_compile_options(${vt_target} PUBLIC ${flag})
   endif()
+  unset(flag_supported CACHE)
 endfunction()
 
-if(NOT hasParent)
-  enable_cxx_compiler_flag_if_supported("-Wall")
-  enable_cxx_compiler_flag_if_supported("-pedantic")
-  enable_cxx_compiler_flag_if_supported("-Wshadow")
-  enable_cxx_compiler_flag_if_supported("-Wno-unknown-pragmas")
-  enable_cxx_compiler_flag_if_supported("-Wsign-compare")
-  # Not really a warning, is still diagnostic related..
-  enable_cxx_compiler_flag_if_supported("-ftemplate-backtrace-limit=100")
+function(turn_on_warnings vt_target)
+  if(NOT hasParent)
+    enable_cxx_compiler_flag_if_supported("-Wall")
+    enable_cxx_compiler_flag_if_supported("-pedantic")
+    enable_cxx_compiler_flag_if_supported("-Wshadow")
+    enable_cxx_compiler_flag_if_supported("-Wno-unknown-pragmas")
+    enable_cxx_compiler_flag_if_supported("-Wsign-compare")
+    # Not really a warning, is still diagnostic related..
+    enable_cxx_compiler_flag_if_supported("-ftemplate-backtrace-limit=100")
 
-  if (vt_werror_enabled)   # Treat warning as errors
-    enable_cxx_compiler_flag_if_supported("-Werror")
+    if (vt_werror_enabled)   # Treat warning as errors
+      enable_cxx_compiler_flag_if_supported("-Werror")
+    endif()
   endif()
-endif()
+endfunction()

src/CMakeLists.txt

@@ -234,6 +234,9 @@ target_compile_features(
 include(SetCXXCompilerFlags)
 set_darma_compiler_flags(${VIRTUAL_TRANSPORT_LIBRARY})
 
+include(turn_on_warnings)
+turn_on_warnings(${VIRTUAL_TRANSPORT_LIBRARY})
+
 if (vt_gold_linker_enabled)
   if (UNIX AND NOT APPLE)
     execute_process(