我正在使用nRf51开发应用程序：
我试图创建一个makefile，其中所有源文件目录和对象目录都不同。我的makefile需要规则来定位*.o文件，这些文件的源文件位于与项目目录不同的目录中。我应该如何修改makefile，以便它可以从不同的目录编译C源文件？
在make执行cmd.exe后，我得到：
rm -rf _build
makefile
mkdir _build
make: *** No rule to make target `_build/system_nrf51.o', needed by `nrf51422_xxac'. Stop.
我的Makefile看起来像：
`PROJECT_NAME := blinky_blank_pca10028
export OUTPUT_FILENAME
#MAKEFILE_NAME := $(CURDIR)/$(word $(words $(MAKEFILE_LIST)),$(MAKEFILE_LIST))
MAKEFILE_NAME := $(MAKEFILE_LIST)
MAKEFILE_DIR := $(dir $(MAKEFILE_NAME) )
TOOLCHAIN_PATH = C:/nRF51_SDK_7.2.0_cf547b5
TEMPLATE_PATH = $(TOOLCHAIN_PATH)/components/toolchain/gcc
ifeq ($(OS),Windows_NT)
include $(TEMPLATE_PATH)/Makefile.windows
else
include $(TEMPLATE_PATH)/Makefile.posix
endif
MK := mkdir
RM := rm -rf
#echo suspend
ifeq ("$(VERBOSE)","1")
NO_ECHO :=
else
NO_ECHO := @
endif
# Toolchain commands
CC := "$(GNU_INSTALL_ROOT)/bin/$(GNU_PREFIX)-gcc"
AS := "$(GNU_INSTALL_ROOT)/bin/$(GNU_PREFIX)-as"
AR := "$(GNU_INSTALL_ROOT)/bin/$(GNU_PREFIX)-ar" -r
LD := "$(GNU_INSTALL_ROOT)/bin/$(GNU_PREFIX)-ld"
NM := "$(GNU_INSTALL_ROOT)/bin/$(GNU_PREFIX)-nm"
OBJDUMP := "$(GNU_INSTALL_ROOT)/bin/$(GNU_PREFIX)-objdump"
OBJCOPY := "$(GNU_INSTALL_ROOT)/bin/$(GNU_PREFIX)-objcopy"
SIZE := "$(GNU_INSTALL_ROOT)/bin/$(GNU_PREFIX)-size"
#function for removing duplicates in a list
remduplicates = $(strip $(if $1,$(firstword $1) $(call remduplicates,$(filter-out $(firstword $1),$1))))
#source common to all targets
C_SOURCE_FILES += \
$(TOOLCHAIN_PATH)/components/toolchain/system_nrf51.c \
../../../Main.c \
$(TOOLCHAIN_PATH)/components/drivers_nrf/hal/nrf_delay.c \
#assembly files common to all targets
ASM_SOURCE_FILES = $(TOOLCHAIN_PATH)/components/toolchain/gcc/gcc_startup_nrf51.s
#includes common to all targets
INC_PATHS = -I../../../
INC_PATHS += -I$(TOOLCHAIN_PATH)/components/toolchain/gcc
INC_PATHS += -I$(TOOLCHAIN_PATH)/components/toolchain
INC_PATHS += -I$(TOOLCHAIN_PATH)/components/drivers_nrf/hal
INC_PATHS += -I$(TOOLCHAIN_PATH)/examples/peripheral/bsp
OBJECT_DIRECTORY = _build
LISTING_DIRECTORY = $(OBJECT_DIRECTORY)
OUTPUT_BINARY_DIRECTORY = $(OBJECT_DIRECTORY)
# Sorting removes duplicates
BUILD_DIRECTORIES := $(sort $(OBJECT_DIRECTORY) $(OUTPUT_BINARY_DIRECTORY) $(LISTING_DIRECTORY) )
#flags common to all targets
CFLAGS = -DNRF51
CFLAGS += -DBSP_DEFINES_ONLY
CFLAGS += -DBOARD_PCA10028
CFLAGS += -mcpu=cortex-m0
CFLAGS += -mthumb -mabi=aapcs --std=gnu99
CFLAGS += -Wall -Werror -O3
CFLAGS += -mfloat-abi=soft
# keep every function in separate section. This will allow linker to dump unused functions
CFLAGS += -ffunction-sections -fdata-sections -fno-strict-aliasing
CFLAGS += -flto -fno-builtin
# keep every function in separate section. This will allow linker to dump unused functions
LDFLAGS += -Xlinker -Map=$(LISTING_DIRECTORY)/$(OUTPUT_FILENAME).map
LDFLAGS += -mthumb -mabi=aapcs -L $(TEMPLATE_PATH) -T$(LINKER_SCRIPT)
LDFLAGS += -mcpu=cortex-m0
# let linker to dump unused sections
LDFLAGS += -Wl,--gc-sections
# use newlib in nano version
LDFLAGS += --specs=nano.specs -lc -lnosys
# Assembler flags
ASMFLAGS += -x assembler-with-cpp
ASMFLAGS += -DNRF51
ASMFLAGS += -DBSP_DEFINES_ONLY
ASMFLAGS += -DBOARD_PCA10028
#default target - first one defined
default: clean nrf51422_xxac
#building all targets
all: clean
$(NO_ECHO)$(MAKE) -f $(MAKEFILE_NAME) -C $(MAKEFILE_DIR) -e cleanobj
$(NO_ECHO)$(MAKE) -f $(MAKEFILE_NAME) -C $(MAKEFILE_DIR) -e nrf51422_xxac
#target for printing all targets
help:
@echo following targets are available:
@echo nrf51422_xxac
C_SOURCE_FILE_NAMES = $(notdir $(C_SOURCE_FILES))
C_PATHS = $(call remduplicates, $(dir $(C_SOURCE_FILES) ) )
C_OBJECTS = $(addprefix $(OBJECT_DIRECTORY)/, $(C_SOURCE_FILE_NAMES:.c=.o) )
ASM_SOURCE_FILE_NAMES = $(notdir $(ASM_SOURCE_FILES))
ASM_PATHS = $(call remduplicates, $(dir $(ASM_SOURCE_FILES) ))
ASM_OBJECTS = $(addprefix $(OBJECT_DIRECTORY)/, $(ASM_SOURCE_FILE_NAMES:.s=.o) )
vpath %.c $(C_PATHS)
vpath %.s $(ASM_PATHS)
OBJECTS = $(C_OBJECTS) $(ASM_OBJECTS)
nrf51422_xxac: OUTPUT_FILENAME := nrf51422_xxac
nrf51422_xxac: LINKER_SCRIPT=$(TOOLCHAIN_PATH)/components/toolchain/gcc/gcc_nrf51_blank_xxac.ld
nrf51422_xxac: $(BUILD_DIRECTORIES) $(OBJECTS)
@echo Linking target: $(OUTPUT_FILENAME).out
$(NO_ECHO)$(CC) $(LDFLAGS) $(OBJECTS) $(LIBS) -o $(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).out
$(NO_ECHO)$(MAKE) -f $(MAKEFILE_NAME) -C $(MAKEFILE_DIR) -e finalize
## Create build directories
$(BUILD_DIRECTORIES):
@echo $(MAKEFILE_NAME)
$(MK) $@
# Create objects from C SRC files
$(OBJECT_DIRECTORY)/%.o: %.c
@echo Compiling file: $(notdir $<)
$(NO_ECHO)$(CC) $(CFLAGS) $(INC_PATHS) -c -o $@ $<
# Assemble files
$(OBJECT_DIRECTORY)/%.o: %.s
@echo Compiling file: $(notdir $<)
$(NO_ECHO)$(CC) $(ASMFLAGS) $(INC_PATHS) -c -o $@ $<
# Link
$(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).out: $(BUILD_DIRECTORIES) $(OBJECTS)
@echo Linking target: $(OUTPUT_FILENAME).out
$(NO_ECHO)$(CC) $(LDFLAGS) $(OBJECTS) $(LIBS) -o $(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).out
## Create binary .bin file from the .out file
$(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).bin: $(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).out
@echo Preparing: $(OUTPUT_FILENAME).bin
$(NO_ECHO)$(OBJCOPY) -O binary $(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).out $(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).bin
## Create binary .hex file from the .out file
$(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).hex: $(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).out
@echo Preparing: $(OUTPUT_FILENAME).hex
$(NO_ECHO)$(OBJCOPY) -O ihex $(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).out $(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).hex
finalize: genbin genhex echosize
genbin:
@echo Preparing: $(OUTPUT_FILENAME).bin
$(NO_ECHO)$(OBJCOPY) -O binary $(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).out $(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).bin
## Create binary .hex file from the .out file
genhex:
@echo Preparing: $(OUTPUT_FILENAME).hex
$(NO_ECHO)$(OBJCOPY) -O ihex $(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).out $(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).hex
echosize:
-@echo ""
$(NO_ECHO)$(SIZE) $(OUTPUT_BINARY_DIRECTORY)/$(OUTPUT_FILENAME).out
-@echo ""
clean:
$(RM) $(BUILD_DIRECTORIES)
cleanobj:
$(RM) $(BUILD_DIRECTORIES)/*.o
flash: $(MAKECMDGOALS)
@echo Flashing: $(OUTPUT_BINARY_DIRECTORY)/$<.hex
nrfjprog --reset --program $(OUTPUT_BINARY_DIRECTORY)/$<.hex`
提前谢谢。