coding_guideline: Add an option to enforce rules

Add a Kconfig option to enable compiler flags that help to enforce
some code guideline rules.

Note: As the current code base is not in compliance with the adopted
code guideline, some rules will generate warnings during the
build. This is intended to help to spot violations.

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>

CMakeLists.txt

@@ -215,6 +215,14 @@ if(CONFIG_MISRA_SANE)
   zephyr_compile_options($<$<COMPILE_LANGUAGE:CXX>:${CPP_MISRA_SANE_FLAG}>)
 endif()
 
+# This is intend to be temporary. Once we have fixed the violations that
+# prevents build Zephyr, these flags shall be part of the default flags.
+if(CONFIG_CODING_GUIDELINE_CHECK)
+  # @Intent: Obtain toolchain compiler flags relating to coding guideline
+  toolchain_cc_warning_error_coding_guideline_check(CC_CODING_GUIDELINE_CHECK_FLAG)
+  zephyr_compile_options($<$<COMPILE_LANGUAGE:C>:${CC_CODING_GUIDELINE_CHECK_FLAG}>)
+endif()
+
 # @Intent: Set compiler specific macro inclusion of AUTOCONF_H
 toolchain_cc_imacros(${AUTOCONF_H})
 

Kconfig.zephyr

@@ -171,6 +171,12 @@ endmenu
 
 menu "Compiler Options"
 
+config CODING_GUIDELINE_CHECK
+	bool "Enforce coding guideline rules"
+	help
+	  Use available compiler flags to check coding guideline rules during
+	  the build.
+
 config NATIVE_APPLICATION
 	bool "Build as a native host application"
 	help

cmake/compiler/clang/target_warnings.cmake

@@ -116,6 +116,14 @@ macro(toolchain_cc_cpp_warning_error_misra_sane dest_var_name)
   set_ifndef(${dest_var_name} "-Werror=vla")
 endmacro()
 
+macro(toolchain_cc_warning_error_coding_guideline_check dest_var_name)
+  if (NOT ${dest_var_name})
+    set(${dest_var_name}
+      -Wvla
+      )
+  endif()
+endmacro()
+
 # List the warnings that are not supported for C++ compilations
 
 list(APPEND CXX_EXCLUDED_OPTIONS

cmake/compiler/gcc/target_warnings.cmake

@@ -109,6 +109,14 @@ macro(toolchain_cc_cpp_warning_error_misra_sane dest_var_name)
   set_ifndef(${dest_var_name} "-Werror=vla")
 endmacro()
 
+macro(toolchain_cc_warning_error_coding_guideline_check dest_var_name)
+  if (NOT ${dest_var_name})
+    set(${dest_var_name}
+      -Wvla
+      )
+  endif()
+endmacro()
+
 # List the warnings that are not supported for C++ compilations
 
 list(APPEND CXX_EXCLUDED_OPTIONS