Adding experimental clang compiler support for arm-none-eabi

- Currently builds larger binaries than gcc (RAM)

CMakeLists.txt

@@ -28,6 +28,20 @@ set( CHIP
 
 
 
+###
+# Compiler Selection
+#
+
+#| *** EXPERIMENTAL ***
+#| Stick with gcc unless you know what you're doing
+#| Currently only arm is supported with clang
+set( COMPILER
+	"gcc"	# arm-none-eabi-gcc / avr-gcc - Default
+#	"clang" # arm-none-eabi
+	CACHE STRING "Compiler Type" )
+
+
+
 ###
 # Compiler Intialization
 #

Lib/CMake/arm.cmake

@@ -13,9 +13,20 @@
 
 #| Set the Compilers (must be set first)
 include( CMakeForceCompiler )
-cmake_force_c_compiler  ( arm-none-eabi-gcc ARMCCompiler )
+message( STATUS "Compiler Selected:" )
-cmake_force_cxx_compiler( arm-none-eabi-g++ ARMCxxCompiler )
+if ( "${COMPILER}" MATCHES "gcc" )
-set( _CMAKE_TOOLCHAIN_PREFIX arm-none-eabi- )
+	cmake_force_c_compiler  ( arm-none-eabi-gcc ARMCCompiler )
+	cmake_force_cxx_compiler( arm-none-eabi-g++ ARMCxxCompiler )
+	set( _CMAKE_TOOLCHAIN_PREFIX arm-none-eabi- )
+	message( "gcc" )
+elseif ( "${COMPILER}" MATCHES "clang" )
+	cmake_force_c_compiler  ( clang   ARMCCompiler )
+	cmake_force_cxx_compiler( clang++ ARMCxxCompiler )
+	set( _CMAKE_TOOLCHAIN_PREFIX llvm- )
+	message( "clang" )
+else ()
+	message( AUTHOR_WARNING "COMPILER: ${COMPILER} - Unknown compiler selection" )
+endif ()
 
 
 
@@ -134,6 +145,8 @@ set( WARN "-Wall -ggdb3" )
 if( BOOTLOADER )
 	set( TUNING "-D_bootloader_ -Wno-main -msoft-float -mthumb -fplan9-extensions -ffunction-sections -fdata-sections -fno-builtin -fstrict-volatile-bitfields -flto -fno-use-linker-plugin -nostdlib" )
 	#set( TUNING "-mthumb -fdata-sections -ffunction-sections -fno-builtin -msoft-float -fstrict-volatile-bitfields -flto -fno-use-linker-plugin -fwhole-program -Wno-main -nostartfiles -fplan9-extensions -D_bootloader_" )
+elseif ( "${COMPILER}" MATCHES "clang" )
+	set( TUNING "-target arm-none-eabi -mthumb -nostdlib -fdata-sections -ffunction-sections -fshort-wchar -fno-builtin" )
 else()
 	set( TUNING "-mthumb -nostdlib -fdata-sections -ffunction-sections -fshort-wchar -fno-builtin -nostartfiles" )
 endif()
@@ -181,5 +194,9 @@ set( BIN_FLAGS -O binary )
 
 
 #| Lss Flags
-set( LSS_FLAGS -h -S -z )
+if ( "${COMPILER}" MATCHES "clang" )
+	set( LSS_FLAGS -section-headers -triple=arm-none-eabi )
+else ()
+	set( LSS_FLAGS -h -S -z )
+endif ()
 

Lib/CMake/build.cmake

@@ -33,22 +33,33 @@ set_target_properties( ${TARGET_ELF} PROPERTIES
 	SUFFIX ""                               # XXX Force Windows to keep the .exe off
 )
 
+#| llvm-clang does not have an objcopy equivalent
+if ( "${COMPILER}" MATCHES "clang" )
+	if ( "${COMPILER_FAMILY}" MATCHES "arm" )
+		set ( OBJ_COPY arm-none-eabi-objcopy )
+	elseif ( "${COMPILER_FAMILY}" MATCHES "arm" )
+		set ( OBJ_COPY avr-objcopy )
+	endif ()
+else ()
+	set ( OBJ_COPY ${CMAKE_OBJCOPY} )
+endif ()
+
 
 #| Convert the .ELF into a .bin to load onto the McHCK
-if( DEFINED DFU )
+if ( DEFINED DFU )
 	set( TARGET_BIN ${TARGET}.dfu.bin )
 	add_custom_command( TARGET ${TARGET_ELF} POST_BUILD
-		COMMAND ${CMAKE_OBJCOPY} ${BIN_FLAGS} ${TARGET_ELF} ${TARGET_BIN}
+		COMMAND ${OBJ_COPY} ${BIN_FLAGS} ${TARGET_ELF} ${TARGET_BIN}
 		COMMENT "Creating dfu binary file:      ${TARGET_BIN}"
 	)
-endif()
+endif ()
 
 
 #| Convert the .ELF into a .HEX to load onto the Teensy
 if ( DEFINED TEENSY )
 	set( TARGET_HEX ${TARGET}.teensy.hex )
 	add_custom_command( TARGET ${TARGET_ELF} POST_BUILD
-		COMMAND ${CMAKE_OBJCOPY} ${HEX_FLAGS} ${TARGET_ELF} ${TARGET_HEX}
+		COMMAND ${OBJ_COPY} ${HEX_FLAGS} ${TARGET_ELF} ${TARGET_HEX}
 		COMMENT "Creating iHex file to load:    ${TARGET_HEX}"
 	)
 endif()