RPi: add clang & clang-check support

CMakeLists.txt

@@ -228,6 +228,11 @@ find_package(PythonInterp REQUIRED)
 #
 enable_testing()
 
+#=============================================================================
+# generate compile command database
+#
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
 #=============================================================================
 # check required toolchain variables
 #

Tools/clang-check.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+COMPILE_DB=$(/bin/pwd)/build_posix_rpi_cross;
+BIN=${RPI_TOOLCHAIN_DIR}/gcc-linaro-arm-linux-gnueabihf-raspbian/bin
+
+CXX_INC=$(cd ${RPI_TOOLCHAIN_DIR}/gcc-linaro-arm-linux-gnueabihf-raspbian/arm-linux-gnueabihf/include/c++/*; pwd)
+
+EXTRA_ARG1=-I${CXX_INC}
+EXTRA_ARG2=-I${CXX_INC}/arm-linux-gnueabihf
+EXTRA_ARG3=-I${CXX_INC}/backward
+
+grep file ${COMPILE_DB}/compile_commands.json |
+awk '{ print $2; }' |
+sed 's/\"//g' |
+while read FILE; do
+    (cd $(dirname ${FILE});
+    ${BIN}/clang-check -analyze -p ${COMPILE_DB} --extra-arg=${EXTRA_ARG1} --extra-arg=${EXTRA_ARG2} --extra-arg=${EXTRA_ARG3} $(basename ${FILE})
+    );
+  done

cmake/configs/posix_rpi_cross.cmake

@@ -1,6 +1,11 @@
 include(configs/posix_rpi_common)
 
-set(CMAKE_TOOLCHAIN_FILE ${CMAKE_SOURCE_DIR}/cmake/toolchains/Toolchain-arm-linux-gnueabihf-raspbian.cmake)
+if("$ENV{RPI_USE_CLANG}" STREQUAL "1")
+	set(CMAKE_TOOLCHAIN_FILE ${CMAKE_SOURCE_DIR}/cmake/toolchains/Toolchain-arm-linux-clang-gnueabihf-raspbian.cmake)
+else()
+	set(CMAKE_TOOLCHAIN_FILE ${CMAKE_SOURCE_DIR}/cmake/toolchains/Toolchain-arm-linux-gnueabihf-raspbian.cmake)
+endif()
+
 
 set(CMAKE_PROGRAM_PATH
 	"${RPI_TOOLCHAIN_DIR}/gcc-linaro-arm-linux-gnueabihf-raspbian/bin"

cmake/posix/px4_impl_posix.cmake

@@ -223,8 +223,19 @@ if ("${BOARD}" STREQUAL "eagle" OR "${BOARD}" STREQUAL "excelsior")
 		-Wl,-rpath-link,${HEXAGON_ARM_SYSROOT}/lib/arm-linux-gnueabihf
 		--sysroot=${HEXAGON_ARM_SYSROOT}
 		)
-else()
+elseif ("${BOARD}" STREQUAL "rpi" AND "$ENV{RPI_USE_CLANG}" STREQUAL "1")
+
+	# Add the toolchain specific flags
+	set(clang_added_flags
+		-m32
+		--target=arm-linux-gnueabihf
+		-ccc-gcc-name arm-linux-gnueabihf
+		--sysroot=${RPI_TOOLCHAIN_DIR}/gcc-linaro-arm-linux-gnueabihf-raspbian/arm-linux-gnueabihf/libc/)
 
+	set(added_c_flags ${POSIX_CMAKE_C_FLAGS} ${clang_added_flags})
+	set(added_cxx_flags ${POSIX_CMAKE_CXX_FLAGS} ${clang_added_flags})
+	set(added_exe_linker_flags ${POSIX_CMAKE_EXE_LINKER_FLAGS} ${clang_added_flags})
+else()
 	# Add the toolchain specific flags
         set(added_cflags ${POSIX_CMAKE_C_FLAGS})
         set(added_cxx_flags ${POSIX_CMAKE_CXX_FLAGS})

cmake/toolchains/Toolchain-arm-linux-clang-gnueabihf-raspbian.cmake

@@ -0,0 +1,69 @@
+include(CMakeForceCompiler)
+
+if ($ENV{RPI_TOOLCHAIN_DIR} STREQUAL "")
+        message(FATAL_ERROR "RPI_TOOLCHAIN_DIR not set")
+else()
+        set(RPI_TOOLCHAIN_DIR $ENV{RPI_TOOLCHAIN_DIR})
+endif()
+
+# this one is important
+set(CMAKE_SYSTEM_NAME Generic)
+
+#this one not so much
+set(CMAKE_SYSTEM_VERSION 1)
+
+# specify the cross compiler
+# requires a symbolic link typically from /usr/bin/clang
+find_program(C_COMPILER clang
+	PATHS ${RPI_TOOLCHAIN_DIR}/gcc-linaro-arm-linux-gnueabihf-raspbian/bin
+	NO_DEFAULT_PATH
+	)
+
+if(NOT C_COMPILER)
+	message(FATAL_ERROR "could not find C compiler")
+endif()
+cmake_force_c_compiler(${C_COMPILER} Clang)
+
+find_program(CXX_COMPILER clang++
+	PATHS ${RPI_TOOLCHAIN_DIR}/gcc-linaro-arm-linux-gnueabihf-raspbian/bin
+	NO_DEFAULT_PATH
+	)
+
+if(NOT CXX_COMPILER)
+	message(FATAL_ERROR "could not find C++ compiler")
+endif()
+cmake_force_cxx_compiler(${CXX_COMPILER} Clang)
+
+# compiler tools
+foreach(tool objcopy nm ld)
+	string(TOUPPER ${tool} TOOL)
+	find_program(${TOOL} arm-linux-gnueabihf-${tool}
+		PATHS ${RPI_TOOLCHAIN_DIR}/gcc-linaro-arm-linux-gnueabihf-raspbian/bin
+		NO_DEFAULT_PATH
+		)
+	if(NOT ${TOOL})
+		message(FATAL_ERROR "could not find arm-linux-gnueabihf-${tool}")
+	endif()
+endforeach()
+
+# os tools
+foreach(tool echo grep rm mkdir nm cp touch make unzip)
+	string(TOUPPER ${tool} TOOL)
+	find_program(${TOOL} ${tool})
+	if(NOT ${TOOL})
+		message(FATAL_ERROR "could not find ${TOOL}")
+	endif()
+endforeach()
+
+add_definitions(
+	-D __RPI
+	)
+
+# where is the target environment
+set(CMAKE_FIND_ROOT_PATH  get_file_component(${C_COMPILER} PATH))
+
+# search for programs in the build host directories
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+# for libraries and headers in the target directories
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)