clang samd21 build but has issue as samd51

examples/build_system/cmake/cpu/cortex-m0.cmake

@@ -9,7 +9,7 @@ if (TOOLCHAIN STREQUAL "gcc")
 elseif (TOOLCHAIN STREQUAL "clang")
   set(TOOLCHAIN_COMMON_FLAGS
     --target=arm-none-eabi
-    -mcpu=cortex-m0plus
+    -mcpu=cortex-m0
     )
   set(FREERTOS_PORT GCC_ARM_CM0 CACHE INTERNAL "")
 

examples/build_system/cmake/cpu/cortex-m0plus.cmake

@@ -7,7 +7,11 @@ if (TOOLCHAIN STREQUAL "gcc")
   set(FREERTOS_PORT GCC_ARM_CM0 CACHE INTERNAL "")
 
 elseif (TOOLCHAIN STREQUAL "clang")
-  message(FATAL_ERROR "Clang is not supported for this target")
+  set(TOOLCHAIN_COMMON_FLAGS
+    --target=arm-none-eabi
+    -mcpu=cortex-m0plus
+    )
+  set(FREERTOS_PORT GCC_ARM_CM0 CACHE INTERNAL "")
 
 elseif (TOOLCHAIN STREQUAL "iar")
   set(TOOLCHAIN_COMMON_FLAGS

hw/bsp/samd21/family.cmake

@@ -18,12 +18,23 @@ set(OPENOCD_OPTION "-f interface/cmsis-dap.cfg -c \"transport select swd\" -f ta
 # only need to be built ONCE for all examples
 function(add_board_target BOARD_TARGET)
   if (NOT TARGET ${BOARD_TARGET})
+    set(LD_FILE_Clang ${LD_FILE_GNU})
+    if (NOT DEFINED LD_FILE_${CMAKE_C_COMPILER_ID})
+      message(FATAL_ERROR "LD_FILE_${CMAKE_C_COMPILER_ID} not defined")
+    endif ()
+
+    if (NOT DEFINED STARTUP_FILE_${CMAKE_C_COMPILER_ID})
+      set(STARTUP_FILE_GNU ${SDK_DIR}/gcc/gcc/startup_samd21.c)
+      set(STARTUP_FILE_Clang ${STARTUP_FILE_GNU})
+    endif ()
+
     add_library(${BOARD_TARGET} STATIC
       ${SDK_DIR}/gcc/system_samd21.c
       ${SDK_DIR}/hpl/gclk/hpl_gclk.c
       ${SDK_DIR}/hpl/pm/hpl_pm.c
       ${SDK_DIR}/hpl/sysctrl/hpl_sysctrl.c
       ${SDK_DIR}/hal/src/hal_atomic.c
+      ${STARTUP_FILE_${CMAKE_C_COMPILER_ID}}
       )
     target_include_directories(${BOARD_TARGET} PUBLIC
       ${SDK_DIR}
@@ -40,24 +51,16 @@ function(add_board_target BOARD_TARGET)
 
     update_board(${BOARD_TARGET})
 
-    if (NOT DEFINED LD_FILE_${CMAKE_C_COMPILER_ID})
-      message(FATAL_ERROR "LD_FILE_${CMAKE_C_COMPILER_ID} not defined")
-    endif ()
-
-    if (NOT DEFINED STARTUP_FILE_${CMAKE_C_COMPILER_ID})
-      set(STARTUP_FILE_GNU ${SDK_DIR}/gcc/gcc/startup_samd21.c)
-    endif ()
-
-    target_sources(${BOARD_TARGET} PRIVATE
-      ${STARTUP_FILE_${CMAKE_C_COMPILER_ID}}
-      )
-
     if (CMAKE_C_COMPILER_ID STREQUAL "GNU")
       target_link_options(${BOARD_TARGET} PUBLIC
         "LINKER:--script=${LD_FILE_GNU}"
         -nostartfiles
         --specs=nosys.specs --specs=nano.specs
         )
+    elseif (CMAKE_C_COMPILER_ID STREQUAL "Clang")
+      target_link_options(${BOARD_TARGET} PUBLIC
+        "LINKER:--script=${LD_FILE_Clang}"
+        )
     elseif (CMAKE_C_COMPILER_ID STREQUAL "IAR")
       target_link_options(${BOARD_TARGET} PUBLIC
         "LINKER:--config=${LD_FILE_IAR}"

hw/bsp/samd51/family.cmake

@@ -60,7 +60,6 @@ function(add_board_target BOARD_TARGET)
     elseif (CMAKE_C_COMPILER_ID STREQUAL "Clang")
       target_link_options(${BOARD_TARGET} PUBLIC
         "LINKER:--script=${LD_FILE_Clang}"
-        #"LINKER:-lcrt0"
         )
     elseif (CMAKE_C_COMPILER_ID STREQUAL "IAR")
       target_link_options(${BOARD_TARGET} PUBLIC