cmake: Toolchain abstraction: Introduce toolchain_cc_warning_dw_[1-3]

The introduced macros are placeholders for the cmake parameter warning
level.

The intent here is to abstract Zephyr's dependence on toolchains,
thus allowing for easier porting to other, perhaps commercial,
toolchains and/or usecases.

No functional change expected.

Signed-off-by: Danny Oerndrup <daor@demant.com>

CMakeLists.txt

@@ -240,52 +240,17 @@ endif()
 # W=2 - warnings that occur quite often but may still be relevant
 # W=3 - the more obscure warnings, can most likely be ignored
 # ==========================================================================
+# @Intent Add cmake -DW toolchain supported warnings, if any
 if(W MATCHES "1")
-  zephyr_compile_options(
-    -Wextra
-    -Wunused
-    -Wno-unused-parameter
-    -Wmissing-declarations
-    -Wmissing-format-attribute
-    -Wold-style-definition
-    )
-  zephyr_cc_option(
-    -Wmissing-prototypes
-    -Wmissing-include-dirs
-    -Wunused-but-set-variable
-    -Wno-missing-field-initializers
-    )
+  toolchain_cc_warning_dw_1()
 endif()
 
 if(W MATCHES "2")
-  zephyr_compile_options(
-    -Waggregate-return
-    -Wcast-align
-    -Wdisabled-optimization
-    -Wnested-externs
-    -Wshadow
-    )
-  zephyr_cc_option(
-    -Wlogical-op
-    -Wmissing-field-initializers
-    )
+  toolchain_cc_warning_dw_2()
 endif()
 
 if(W MATCHES "3")
-  zephyr_compile_options(
-    -Wbad-function-cast
-    -Wcast-qual
-    -Wconversion
-    -Wpacked
-    -Wpadded
-    -Wpointer-arith
-    -Wredundant-decls
-    -Wswitch-default
-    )
-  zephyr_cc_option(
-    -Wpacked-bitfield-compat
-    -Wvla
-    )
+  toolchain_cc_warning_dw_3()
 endif()
 
 

cmake/compiler/clang/target.cmake

@@ -79,6 +79,7 @@ include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_optimizations.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_cpp.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_asm.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_baremetal.cmake)
+include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_warnings.cmake)
 
 macro(toolchain_cc_security_fortify)
   # No op, clang doesn't understand fortify at all

cmake/compiler/gcc/target.cmake

@@ -139,3 +139,4 @@ include(${ZEPHYR_BASE}/cmake/compiler/${COMPILER}/target_optimizations.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/${COMPILER}/target_cpp.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/${COMPILER}/target_asm.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/${COMPILER}/target_baremetal.cmake)
+include(${ZEPHYR_BASE}/cmake/compiler/${COMPILER}/target_warnings.cmake)

cmake/compiler/gcc/target_warnings.cmake

@@ -0,0 +1,57 @@
+# SPDX-License-Identifier: Apache-2.0
+
+# See root CMakeLists.txt for description and expectations of these macros
+
+macro(toolchain_cc_warning_dw_1)
+
+  zephyr_compile_options(
+    -Wextra
+    -Wunused
+    -Wno-unused-parameter
+    -Wmissing-declarations
+    -Wmissing-format-attribute
+    -Wold-style-definition
+    )
+  zephyr_cc_option(
+    -Wmissing-prototypes
+    -Wmissing-include-dirs
+    -Wunused-but-set-variable
+    -Wno-missing-field-initializers
+    )
+
+endmacro()
+
+macro(toolchain_cc_warning_dw_2)
+
+  zephyr_compile_options(
+    -Waggregate-return
+    -Wcast-align
+    -Wdisabled-optimization
+    -Wnested-externs
+    -Wshadow
+    )
+  zephyr_cc_option(
+    -Wlogical-op
+    -Wmissing-field-initializers
+    )
+
+endmacro()
+
+macro(toolchain_cc_warning_dw_3)
+
+  zephyr_compile_options(
+    -Wbad-function-cast
+    -Wcast-qual
+    -Wconversion
+    -Wpacked
+    -Wpadded
+    -Wpointer-arith
+    -Wredundant-decls
+    -Wswitch-default
+    )
+  zephyr_cc_option(
+    -Wpacked-bitfield-compat
+    -Wvla
+    )
+
+endmacro()

cmake/compiler/host-gcc/target.cmake

@@ -88,3 +88,4 @@ include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_optimizations.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_cpp.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_asm.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_baremetal.cmake)
+include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_warnings.cmake)

cmake/compiler/xcc/target.cmake

@@ -82,3 +82,4 @@ include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_optimizations.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_cpp.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_asm.cmake)
 include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_baremetal.cmake)
+include(${ZEPHYR_BASE}/cmake/compiler/gcc/target_warnings.cmake)