cmake: sca: Add cppcheck

This commit adds cppcheck as a Static Analyser using Zephyr's SCA
framework.

By specifing -DZEPHYR_SCA_VARIANT=cppcheck to west build, the file
sca/cppcheck/index.html will be generated.

Signed-off-by: Reto Schneider <[email protected]>

Author: rettichschnidi

cmake/sca/cppcheck/sca.cmake

@@ -0,0 +1,136 @@
+# SPDX-License-Identifier: Apache-2.0
+#
+# SPDX-FileCopyrightText: Copyright (c) 2025 GARDENA GmbH
+
+# If not specified manually, let Cppcheck to use all available (logical) CPU
+# cores.
+if(NOT DEFINED CPPCHECK_JOBS_COUNT)
+  cmake_host_system_information(RESULT CPPCHECK_JOBS_COUNT
+                                QUERY NUMBER_OF_LOGICAL_CORES)
+endif()
+
+find_program(CPPCHECK_EXE NAMES cppcheck REQUIRED)
+message(STATUS "Found SCA: cppcheck (${CPPCHECK_EXE})")
+
+# Defaulting to exhaustive to prevent normalCheckLevelMaxBranches "findings"
+set(CPPCHECK_CHECK_LEVEL "exhaustive" CACHE STRING
+    "Value of the --check-level argument passed to cppcheck")
+
+# The premium edition exits with a non-zero exit code whenever it finds a bug,
+# causing the SCA infrastructure of Zephyr to quit with an error too.
+# We can prevent this by adding the "--premium=safety-off" argument. However,
+# this is known only the the Premium edition of Cppcheck.
+if(NOT DEFINED CPPCHECK_IS_PREMIUM)
+  execute_process(COMMAND "${CPPCHECK_EXE}" "--version"
+                  OUTPUT_VARIABLE CPPCHECK_VERSION_STRING
+                  COMMAND_ERROR_IS_FATAL ANY)
+  if("${CPPCHECK_VERSION_STRING}" MATCHES "Premium")
+    set(CPPCHECK_IS_PREMIUM 1)
+  endif()
+endif()
+option(CPPCHECK_IS_PREMIUM "Whether we run Cppcheck premium" 0)
+if(CPPCHECK_IS_PREMIUM)
+  set(CPPCHECK_PREMIUM_ARGUMENT "--premium=safety-off")
+  message(STATUS "Using the Premium version of Cppcheck")
+else()
+  set(CPPCHECK_PREMIUM_ARGUMENT "")
+  message(STATUS "Using the Open Source version of Cppcheck")
+endif()
+
+# Cppcheck uses the compile_commands.json as input
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+# Create an output directory for our tool
+set(output_dir ${CMAKE_BINARY_DIR}/sca/cppcheck)
+file(MAKE_DIRECTORY ${output_dir})
+
+# Help Cppcheck parse the Zephyr headers, reduce runtime by ensuring all
+# relevant configs defined
+set_property(
+    GLOBAL
+    APPEND
+    PROPERTY
+        extra_post_build_commands
+            COMMAND
+            ${CMAKE_COMMAND}
+            ARGS
+            -E
+            touch
+            ${output_dir}/compiler-macros.c
+)
+set_property(
+    GLOBAL
+    APPEND
+    PROPERTY extra_post_build_byproducts ${output_dir}/compiler-macros.c
+)
+
+# Note: This works only for GCC and compatibles. Please add support for other
+# compilers!
+set_property(
+    GLOBAL
+    APPEND
+    PROPERTY
+        extra_post_build_commands
+            COMMAND
+            ${CMAKE_C_COMPILER}
+            ARGS
+            -dM
+            -E
+            ${output_dir}/compiler-macros.c
+            -o
+            ${output_dir}/compiler-macros.h
+)
+
+set_property(
+    GLOBAL
+    APPEND
+    PROPERTY extra_post_build_byproducts ${output_dir}/compiler-macros.h
+)
+
+add_custom_target(
+    cppcheck
+    ALL
+    COMMAND
+        ${CPPCHECK_EXE} --project=${CMAKE_BINARY_DIR}/compile_commands.json
+        --xml # Write results in XML format
+        --output-file=${output_dir}/cppcheck.xml # write output to file, not stderr
+        --library=zephyr.cfg # Enable Zephyr specific knowledge
+        --quiet # Suppress progress reporting
+        --include=${CMAKE_BINARY_DIR}/zephyr/include/generated/zephyr/autoconf.h
+        --include=${output_dir}/compiler-macros.h # Use exact compiler macros
+        -j ${CPPCHECK_JOBS_COUNT} # Parallelize analysis
+        -D__cppcheck__ # As recommended by the Cppcheck manual
+        --check-level=${CPPCHECK_CHECK_LEVEL}
+        ${CPPCHECK_PREMIUM_ARGUMENT}
+        ${CODECHECKER_ANALYZE_OPTS}
+    DEPENDS
+        ${CMAKE_BINARY_DIR}/compile_commands.json
+        ${output_dir}/compiler-macros.h
+    BYPRODUCTS ${output_dir}/cppcheck.xml
+    VERBATIM
+)
+
+# Cleanup helper files
+add_custom_command(
+    TARGET cppcheck
+    POST_BUILD
+    COMMAND ${CMAKE_COMMAND}
+    ARGS -E rm ${output_dir}/compiler-macros.c ${output_dir}/compiler-macros.h
+)
+
+find_program(CPPCHECK_HTMLREPORT_EXE NAMES cppcheck-htmlreport REQUIRED)
+message(STATUS "Found SCA: cppcheck-htmlreport (${CPPCHECK_HTMLREPORT_EXE})")
+add_custom_command(
+    TARGET cppcheck
+    POST_BUILD
+    COMMAND
+        ${CPPCHECK_HTMLREPORT_EXE} --title=Zephyr
+        --file=${output_dir}/cppcheck.xml # Read in file created by Cppcheck
+        --report-dir=${output_dir} # Set output directory
+        ${CPPCHECK_HTMLREPORT_OPTS}
+    BYPRODUCTS
+        ${output_dir}/index.html
+        ${output_dir}/stats.html
+        ${output_dir}/style.css
+    VERBATIM
+)