cmake: enable -Wshadow partially for in-tree code

This enables -Wshadow to warn about shadow variables on
in tree code under arch/, boards/, drivers/, kernel/,
lib/, soc/, and subsys/.

Note that this does not enable it globally because
out-of-tree modules will probably take some time to fix
(or not at all depending on the project), and it would be
great to avoid introduction of any new shadow variables
in the meantime.

Also note that this tries to be done in a minimally
invasive way so it is easy to revert when we enable
-Wshadow globally. Source files under modules/, samples/
and tests/ are currently excluded because there does not
seem to be a trivial way to add -Wshadow there without
going through all CMakeLists.txt to add the option
(as there are 1000+ files to change).

Signed-off-by: Daniel Leung <daniel.leung@intel.com>

CMakeLists.txt

@@ -603,12 +603,7 @@ add_subdirectory(lib)
 # property which is set implicitly for custom command outputs
 include(misc/generated/CMakeLists.txt)
 
-if(EXISTS ${SOC_DIR}/${ARCH}/CMakeLists.txt)
-  add_subdirectory(${SOC_DIR}/${ARCH} soc/${ARCH})
-else()
-  add_subdirectory(${SOC_DIR}/${ARCH}/${SOC_PATH} soc/${ARCH}/${SOC_PATH})
-endif()
-
+add_subdirectory(soc)
 add_subdirectory(boards)
 add_subdirectory(subsys)
 add_subdirectory(drivers)

arch/CMakeLists.txt

@@ -1,5 +1,8 @@
 # SPDX-License-Identifier: Apache-2.0
 
+# FIXME: SHADOW_VARS: Remove this once we have enabled -Wshadow globally.
+add_compile_options($<TARGET_PROPERTY:compiler,warning_shadow_variables>)
+
 add_definitions(-D__ZEPHYR_SUPERVISOR__)
 
 include_directories(

boards/CMakeLists.txt

@@ -8,6 +8,11 @@ if(EXISTS ${BOARD_DIR}/CMakeLists.txt)
 	set(build_dir boards/${ARCH}/${BOARD})
   else()
 	unset(build_dir)
+
+	# FIXME: SHADOW_VARS: Remove this once we have enabled -Wshadow globally.
+	#
+	# For now, only enable warning for shadow variables for in-tree boards.
+	add_compile_options($<TARGET_PROPERTY:compiler,warning_shadow_variables>)
   endif()
 
   add_subdirectory(${BOARD_DIR} ${build_dir})

cmake/compiler/arcmwdt/compiler_flags.cmake

@@ -203,3 +203,6 @@ if(CONFIG_ARCMWDT_LIBC)
   # to ASM builds (which may use 'stdbool.h').
   set_property(TARGET asm APPEND PROPERTY required "-I${NOSTDINC}")
 endif()
+
+# Remove after testing that -Wshadow works
+set_compiler_property(PROPERTY warning_shadow_variables)

cmake/compiler/armclang/compiler_flags.cmake

@@ -7,3 +7,6 @@ set_property(TARGET asm APPEND PROPERTY required "--target=${triple}")
 
 # Only the ARM Compiler C library is currently supported.
 set_compiler_property(PROPERTY nostdinc)
+
+# Remove after testing that -Wshadow works
+set_compiler_property(PROPERTY warning_shadow_variables)

cmake/compiler/compiler_flags_template.cmake

@@ -130,3 +130,6 @@ set_compiler_property(PROPERTY no_position_independent)
 # gen_kobject_list.py is does not understand it and end up identifying objects as if
 # they had the same address.
 set_compiler_property(PROPERTY no_global_merge)
+
+# Compiler flag for warning about shadow variables
+set_compiler_property(PROPERTY warning_shadow_variables)

cmake/compiler/gcc/compiler_flags.cmake

@@ -225,3 +225,5 @@ set_compiler_property(PROPERTY no_position_independent
 )
 
 set_compiler_property(PROPERTY no_global_merge "")
+
+set_compiler_property(PROPERTY warning_shadow_variables -Wshadow)

cmake/compiler/icx/compiler_flags.cmake

@@ -1,2 +1,5 @@
 
 include(${ZEPHYR_BASE}/cmake/compiler/clang/compiler_flags.cmake)
+
+# Remove after testing that -Wshadow works
+set_compiler_property(PROPERTY warning_shadow_variables)

cmake/compiler/xcc/compiler_flags.cmake

@@ -12,3 +12,6 @@ set_compiler_property(PROPERTY warning_error_misra_sane)
 
 # XCC does not support -fno-pic and -fno-pie
 set_compiler_property(PROPERTY no_position_independent "")
+
+# Remove after testing that -Wshadow works
+set_compiler_property(PROPERTY warning_shadow_variables)

cmake/compiler/xt-clang/compiler_flags.cmake

@@ -31,3 +31,6 @@ endif()
 
 # Clang version used by Xtensa does not support -fno-pic and -fno-pie
 set_compiler_property(PROPERTY no_position_independent "")
+
+# Remove after testing that -Wshadow works
+set_compiler_property(PROPERTY warning_shadow_variables)

drivers/CMakeLists.txt

@@ -1,5 +1,8 @@
 # SPDX-License-Identifier: Apache-2.0
 
+# FIXME: SHADOW_VARS: Remove this once we have enabled -Wshadow globally.
+add_compile_options($<TARGET_PROPERTY:compiler,warning_shadow_variables>)
+
 add_definitions(-D__ZEPHYR_SUPERVISOR__)
 
 add_subdirectory(disk)

kernel/CMakeLists.txt

@@ -38,6 +38,9 @@ target_link_libraries(kernel INTERFACE ${libkernel})
 
 else()
 
+# FIXME: SHADOW_VARS: Remove this once we have enabled -Wshadow globally.
+add_compile_options($<TARGET_PROPERTY:compiler,warning_shadow_variables>)
+
 list(APPEND kernel_files
   main_weak.c
   banner.c

lib/CMakeLists.txt

@@ -1,5 +1,8 @@
 # SPDX-License-Identifier: Apache-2.0
 
+# FIXME: SHADOW_VARS: Remove this once we have enabled -Wshadow globally.
+add_compile_options($<TARGET_PROPERTY:compiler,warning_shadow_variables>)
+
 add_subdirectory(crc)
 if(NOT CONFIG_EXTERNAL_LIBC)
 add_subdirectory(libc)

soc/CMakeLists.txt

@@ -0,0 +1,16 @@
+# SPDX-License-Identifier: Apache-2.0
+
+# FIXME: SHADOW_VARS: Remove this once we have enabled -Wshadow globally.
+#
+# Limit warning of shadow variables to in-tree SoC files for now.
+cmake_path(IS_PREFIX ZEPHYR_BASE "${SOC_DIR}" NORMALIZE _SOC_IS_IN_TREE)
+if(_SOC_IS_IN_TREE)
+  add_compile_options($<TARGET_PROPERTY:compiler,warning_shadow_variables>)
+endif()
+unset(_SOC_IS_IN_TREE)
+
+if(EXISTS ${SOC_DIR}/${ARCH}/CMakeLists.txt)
+  add_subdirectory(${SOC_DIR}/${ARCH} soc/${ARCH})
+else()
+  add_subdirectory(${SOC_DIR}/${ARCH}/${SOC_PATH} soc/${ARCH}/${SOC_PATH})
+endif()

subsys/CMakeLists.txt

@@ -1,5 +1,16 @@
 # SPDX-License-Identifier: Apache-2.0
 
+# FIXME: SHADOW_VARS: move this before adding shadow variable warning below.
+# This is because, in some build configurations, the external lorawan module
+# is pulled in as though the source files are in main repo. This results in
+# shadow variable warnings being active on these files. Until the module has
+# fixed those shadow variables, keep this here before add_compile_options()
+# below.
+add_subdirectory_ifdef(CONFIG_LORAWAN lorawan)
+
+# FIXME: SHADOW_VARS: Remove this once we have enabled -Wshadow globally.
+add_compile_options($<TARGET_PROPERTY:compiler,warning_shadow_variables>)
+
 add_subdirectory(canbus)
 add_subdirectory(debug)
 add_subdirectory(fb)
@@ -29,7 +40,6 @@ add_subdirectory_ifdef(CONFIG_EMUL emul)
 add_subdirectory_ifdef(CONFIG_IMG_MANAGER dfu)
 add_subdirectory_ifdef(CONFIG_INPUT input)
 add_subdirectory_ifdef(CONFIG_JWT jwt)
-add_subdirectory_ifdef(CONFIG_LORAWAN lorawan)
 add_subdirectory_ifdef(CONFIG_NET_BUF net)
 add_subdirectory_ifdef(CONFIG_RETENTION retention)
 add_subdirectory_ifdef(CONFIG_SENSING sensing)