Suppress null dereference warnings during IPO build

These warnings come from external code (e.g. pugixml, flex/bison
generated) and only appear during link time since IPO re-optimizes the
program at that point. Since we will not fix these we suppress them to
keep the build warning count at zero.

Author: kmurray

CMakeLists.txt

@@ -184,6 +184,19 @@ foreach(flag ${FLEX_BISON_WARN_SUPPRESS_FLAGS_TO_CHECK})
     endif()
 endforeach()
 
+#Suppress IPO link warnings
+set(IPO_LINK_WARN_SUPRESS_FLAGS "")
+set(IPO_LINK_WARN_SUPRESS_FLAGS_TO_CHECK 
+    "-Wno-null-dereference"
+    )
+foreach(flag ${IPO_LINK_WARN_SUPRESS_FLAGS_TO_CHECK})
+    CHECK_CXX_COMPILER_FLAG(${flag} CXX_COMPILER_SUPPORTS_${flag})
+    if(CXX_COMPILER_SUPPORTS_${flag})
+        #Flag supported, so enable it
+        set(IPO_LINK_WARN_SUPRESS_FLAGS "${IPO_LINK_WARN_SUPRESS_FLAGS} ${flag}")
+    endif()
+endforeach()
+
 #
 # Sanitizer flags
 #

ODIN_II/CMakeLists.txt

@@ -135,5 +135,10 @@ add_executable(odin_II ${EXEC_SOURCES})
 target_link_libraries(odin_II
                         libodin_ii)
 
+#Supress IPO link warnings if IPO is enabled
+get_target_property(ODIN_USES_IPO odin_II INTERPROCEDURAL_OPTIMIZATION)
+if (ODIN_USES_IPO)
+    set_target_properties(odin_II PROPERTIES LINK_FLAGS ${IPO_LINK_WARN_SUPRESS_FLAGS})
+endif()
 
 install(TARGETS odin_II libodin_ii DESTINATION bin)

libs/EXTERNAL/libpugixml/CMakeLists.txt

@@ -20,6 +20,6 @@ set(PUGIXML_SUPPRESS_FLAGS -w)
 target_compile_options(libpugixml PRIVATE ${PUGIXML_SUPPRESS_FLAGS})
 
 #Enable compact mode which reduces memory usage.
-add_definitions(-DPUGIXML_COMPACT)
+target_compile_definitions(libpugixml PRIVATE PUGIXML_COMPACT)
 
 install(TARGETS libpugixml DESTINATION bin)

libs/libarchfpga/CMakeLists.txt

@@ -27,4 +27,10 @@ target_link_libraries(libarchfpga
 add_executable(read_arch ${EXEC_SOURCES})
 target_link_libraries(read_arch libarchfpga)
 
+#Supress IPO link warnings if IPO is enabled
+get_target_property(READ_ARCH_USES_IPO read_arch INTERPROCEDURAL_OPTIMIZATION)
+if (READ_ARCH_USES_IPO)
+    set_target_properties(read_arch PROPERTIES LINK_FLAGS ${IPO_LINK_WARN_SUPRESS_FLAGS})
+endif()
+
 install(TARGETS libarchfpga read_arch DESTINATION bin)

utils/fasm/CMakeLists.txt

@@ -28,6 +28,12 @@ target_link_libraries(fasm
 add_executable(genfasm src/main.cpp)
 target_link_libraries(genfasm fasm)
 
+#Supress IPO link warnings if IPO is enabled
+get_target_property(GENFASM_USES_IPO genfasm INTERPROCEDURAL_OPTIMIZATION)
+if (GENFASM_USES_IPO)
+    set_target_properties(genfasm PROPERTIES LINK_FLAGS ${IPO_LINK_WARN_SUPRESS_FLAGS})
+endif()
+
 #Specify link-time dependancies
 install(TARGETS genfasm DESTINATION bin)
 
@@ -44,6 +50,12 @@ set(TEST_SOURCES
 add_executable(test_fasm ${TEST_SOURCES})
 target_link_libraries(test_fasm fasm libcatch)
 
+#Supress IPO link warnings if IPO is enabled
+get_target_property(TEST_FASM_USES_IPO test_fasm INTERPROCEDURAL_OPTIMIZATION)
+if (TEST_FASM_USES_IPO)
+    set_target_properties(test_fasm PROPERTIES LINK_FLAGS ${IPO_LINK_WARN_SUPRESS_FLAGS})
+endif()
+
 add_test(
   NAME test_fasm
   COMMAND test_fasm --use-colour=yes

vpr/CMakeLists.txt

@@ -48,6 +48,12 @@ add_executable(vpr ${EXEC_SOURCES})
 target_link_libraries(vpr
                         libvpr)
 
+#Supress IPO link warnings if IPO is enabled
+get_target_property(VPR_USES_IPO vpr INTERPROCEDURAL_OPTIMIZATION)
+if (VPR_USES_IPO)
+    set_target_properties(vpr PROPERTIES LINK_FLAGS ${IPO_LINK_WARN_SUPRESS_FLAGS})
+endif()
+
 #
 # Profile Guilded Optimization Configuration
 #
@@ -148,6 +154,12 @@ target_link_libraries(test_vpr
                         libcatch
                         libvpr)
 
+#Supress IPO link warnings if IPO is enabled
+get_target_property(TEST_VPR_USES_IPO vpr INTERPROCEDURAL_OPTIMIZATION)
+if (TEST_VPR_USES_IPO)
+    set_target_properties(test_vpr PROPERTIES LINK_FLAGS ${IPO_LINK_WARN_SUPRESS_FLAGS})
+endif()
+
 add_test(NAME test_vpr
     COMMAND test_vpr --use-colour=yes
     WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/test