Clean up handling of compiler flags in CMake. (#17532)

* Move all handling of compilation flags inot compiler flags module.

Also, make including the module do all the required compiler flag
changes.

* Switch compiler flag handling to (mostly) use properties.

This makes it easier to override individual flags on a per-target
basis and also results in slightly simpler CMake code.

* Fix typos in compiler flag handling.

* Fix missing quotes.

3 files changed, 51 insertions, 71 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8214e392e5..4ab193b9f1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -82,15 +82,7 @@ if(NOT CMAKE_BUILD_TYPE)
         set(CMAKE_BUILD_TYPE "Release")
 endif()
 
-option(ENABLE_ADDRESS_SANITIZER "Build with address sanitizer enabled" False)
-mark_as_advanced(ENABLE_ADDRESS_SANITIZER)
-
-if(ENABLE_ADDRESS_SANITIZER)
-        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fsanitize=address")
-endif()
-
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fexceptions")
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CMAKE_C_FLAGS}")
+include(NetdataCompilerFlags)
 
 set(CMAKE_EXPORT_COMPILE_COMMANDS On)
 
@@ -198,45 +190,6 @@ if(NEED_PROTOBUF)
 endif()
 
 #
-# handling of extra compiler flags
-#
-
-include(NetdataCompilerFlags)
-
-# Disable hardening for debug builds by default.
-if(CMAKE_BUILD_TYPE STREQUAL "Debug")
-        option(DISABLE_HARDENING "Disable adding extra compiler flags for hardening" TRUE)
-else()
-        option(DISABLE_HARDENING "Disable adding extra compiler flags for hardening" FALSE)
-endif()
-
-set(EXTRA_HARDENING_C_FLAGS "")
-set(EXTRA_HARDENING_CXX_FLAGS "")
-
-set(EXTRA_OPT_C_FLAGS "")
-set(EXTRA_OPT_CXX_FLAGS "")
-
-if(NOT ${DISABLE_HARDENING})
-        add_double_extra_compiler_flag("stack-protector" "-fstack-protector-strong" "-fstack-protector" EXTRA_HARDENING)
-        add_double_extra_compiler_flag("_FORTIFY_SOURCE" "-D_FORTIFY_SOURCE=3" "-D_FORTIFY_SOURCE=2" EXTRA_HARDENING)
-        add_simple_extra_compiler_flag("stack-clash-protection" "-fstack-clash-protection" EXTRA_HARDENING)
-        add_simple_extra_compiler_flag("-fcf-protection" "-fcf-protection=full" EXTRA_HARDENING)
-        add_simple_extra_compiler_flag("branch-protection" "-mbranch-protection=standard" EXTRA_HARDENING)
-endif()
-
-foreach(FLAG function-sections data-sections)
-        add_simple_extra_compiler_flag("${FLAG}" "-f${FLAG}" EXTRA_OPT)
-endforeach()
-
-add_simple_extra_compiler_flag("-Wbuiltin-macro-redefined" "-Wno-builtin-macro-redefined" EXTRA_OPT)
-
-foreach(RELTYP RELEASE DEBUG RELWITHDEBINFO MINSIZEREL)
-        foreach(L C CXX)
-                set(CMAKE_${L}_FLAGS_${RELTYP} "${CMAKE_${L}_FLAGS_${RELTYP}} ${EXTRA_HARDENING_C_FLAGS} ${EXTRA_OPT_C_FLAGS}")
-        endforeach()
-endforeach()
-
-#
 # detect OS
 #
 
diff --git a/packaging/cmake/Modules/NetdataCompilerFlags.cmake b/packaging/cmake/Modules/NetdataCompilerFlags.cmake
index 894e244ce6..28b43b4ec4 100644
--- a/packaging/cmake/Modules/NetdataCompilerFlags.cmake
+++ b/packaging/cmake/Modules/NetdataCompilerFlags.cmake
@@ -20,30 +20,29 @@ endfunction()
 #
 # If the language flags already match the `match` argument, skip this flag.
 # Otherwise, check for support for `flag` and if support is found, add it to
-# the language-specific `target` flag group.
-function(add_simple_extra_compiler_flag match flag target)
+# the compiler flags for the run.
+function(add_simple_extra_compiler_flag match flag)
         set(CMAKE_REQUIRED_FLAGS "-Werror")
 
         make_cpp_safe_name("${flag}" flag_name)
 
         if(NOT ${CMAKE_C_FLAGS} MATCHES ${match})
                 check_c_compiler_flag("${flag}" HAVE_C_${flag_name})
-                if(HAVE_C_${flag_name})
-                        set(${target}_C_FLAGS "${${target}_C_FLAGS} ${flag}" PARENT_SCOPE)
-                endif()
         endif()
 
         if(NOT ${CMAKE_CXX_FLAGS} MATCHES ${match})
                 check_cxx_compiler_flag("${flag}" HAVE_CXX_${flag_name})
-                if(HAVE_CXX_${flag_name})
-                        set(${target}_CXX_FLAGS "${${target}_CXX_FLAGS} ${flag}" PARENT_SCOPE)
-                endif()
+        endif()
+
+        if(HAVE_C_${flag_name} AND HAVE_CXX_${flag_name})
+            add_compile_options("${flag}")
+            add_link_options("${flag}")
         endif()
 endfunction()
 
 # Same as add_simple_extra_compiler_flag, but check for a second flag if the
 # first one is unsupported.
-function(add_double_extra_compiler_flag match flag1 flag2 target)
+function(add_double_extra_compiler_flag match flag1 flag2)
         set(CMAKE_REQUIRED_FLAGS "-Werror")
 
         make_cpp_safe_name("${flag1}" flag1_name)
@@ -51,25 +50,53 @@ function(add_double_extra_compiler_flag match flag1 flag2 target)
 
         if(NOT ${CMAKE_C_FLAGS} MATCHES ${match})
                 check_c_compiler_flag("${flag1}" HAVE_C_${flag1_name})
-                if(HAVE_C_${flag1_name})
-                        set(${target}_C_FLAGS "${${target}_C_FLAGS} ${flag1}" PARENT_SCOPE)
-                else()
+                if(NOT HAVE_C_${flag1_name})
                         check_c_compiler_flag("${flag2}" HAVE_C_${flag2_name})
-                        if(HAVE_C_${flag2_name})
-                                set(${target}_C_FLAGS "${${target}_C_FLAGS} ${flag2}" PARENT_SCOPE)
-                        endif()
                 endif()
         endif()
 
         if(NOT ${CMAKE_CXX_FLAGS} MATCHES ${match})
                 check_cxx_compiler_flag("${flag1}" HAVE_CXX_${flag1_name})
-                if(HAVE_CXX_${flag1_name})
-                        set(${target}_CXX_FLAGS "${${target}_CXX_FLAGS} ${flag1}" PARENT_SCOPE)
-                else()
+                if(NOT HAVE_CXX_${flag1_name})
                         check_cxx_compiler_flag("${flag2}" HAVE_CXX_${flag2_name})
-                        if(HAVE_CXX_${flag2_name})
-                                set(${target}_CXX_FLAGS "${${target}_CXX_FLAGS} ${flag2}" PARENT_SCOPE)
-                        endif()
                 endif()
         endif()
+
+        if(HAVE_C_${flag1_name} AND HAVE_CXX_${flag1_name})
+            add_compile_options("${flag1}")
+            add_link_options("${flag1}")
+        elseif(HAVE_C_${flag2_name} AND HAVE_CXX${flag2_name})
+            add_compile_options("${flag2}")
+            add_link_options("${flag2}")
+        endif()
 endfunction()
+
+if(CMAKE_BUILD_TYPE STREQUAL "Debug")
+        option(DISABLE_HARDENING "Disable adding extra compiler flags for hardening" TRUE)
+else()
+        option(DISABLE_HARDENING "Disable adding extra compiler flags for hardening" FALSE)
+endif()
+
+option(ENABLE_ADDRESS_SANITIZER "Build with address sanitizer enabled" False)
+mark_as_advanced(ENABLE_ADDRESS_SANITIZER)
+
+if(ENABLE_ADDRESS_SANITIZER)
+        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fsanitize=address")
+endif()
+
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${CMAKE_C_FLAGS}")
+
+if(NOT ${DISABLE_HARDENING})
+        add_double_extra_compiler_flag("stack-protector" "-fstack-protector-strong" "-fstack-protector")
+        add_double_extra_compiler_flag("_FORTIFY_SOURCE" "-D_FORTIFY_SOURCE=3" "-D_FORTIFY_SOURCE=2")
+        add_simple_extra_compiler_flag("stack-clash-protection" "-fstack-clash-protection")
+        add_simple_extra_compiler_flag("-fcf-protection" "-fcf-protection=full")
+        add_simple_extra_compiler_flag("branch-protection" "-mbranch-protection=standard")
+endif()
+
+foreach(FLAG function-sections data-sections)
+        add_simple_extra_compiler_flag("${FLAG}" "-f${FLAG}")
+endforeach()
+
+add_simple_extra_compiler_flag("-Wbuiltin-macro-redefined" "-Wno-builtin-macro-redefined")
+add_simple_extra_compiler_flag("-fexecptions" "-fexceptions")
diff --git a/packaging/cmake/Modules/NetdataProtobuf.cmake b/packaging/cmake/Modules/NetdataProtobuf.cmake
index d4ae3aec61..bc0ffc03be 100644
--- a/packaging/cmake/Modules/NetdataProtobuf.cmake
+++ b/packaging/cmake/Modules/NetdataProtobuf.cmake
@@ -47,8 +47,8 @@ function(netdata_bundle_protobuf)
 
         set(FETCHCONTENT_TRY_FIND_PACKAGE_MODE NEVER)
 
-        string(REPLACE "-fsanitize=address" "" CMAKE_C_FLAGS ${CMAKE_C_FLAGS})
-        string(REPLACE "-fsanitize=address" "" CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS})
+        string(REPLACE "-fsanitize=address" "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
+        string(REPLACE "-fsanitize=address" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
 
         # ignore debhelper
         set(FETCHCONTENT_FULLY_DISCONNECTED Off)