helloworld.elf: $(OBJS) ../src/lscript.ld $(USER_OBJS)
@echo 'Building target: $@'
@echo 'Invoking: ARM v7 gcc linker'
arm-none-eabi-gcc -mcpu=cortex-a9 -mfpu=vfpv3 -mfloat-abi=hard -Wl,-build-id=none -specs=Xilinx.spec -Wl,-T -Wl,../src/lscript.ld -L../../helloworld_bsp/ps7_cortexa9_0/lib -o "helloworld.elf" $(OBJS) $(USER_OBJS) $(LIBS)
@echo 'Finished building target: $@'
@echo ' '
其中依赖的变量“OBJS”“USER_OBJS”为空的，导致没有编译出*.elf文件
USER_OBJS :=
LIBS := -Wl,--start-group,-lxil,-lgcc,-lc,--end-group
LD_SRCS :=
OBJ_SRCS :=
S_SRCS :=
C_SRCS :=
S_UPPER_SRCS :=
O_SRCS :=
EXECUTABLES :=
OBJS :=
S_UPPER_DEPS :=
C_DEPS :=
ELFSIZE :=
Every subdirectory with source files must be described here
SUBDIRS := \
src \
