我正在使用GNU工具，GCC实现构建系统，并使make编译多个目标，将它们链接在一起并创建最终的可执行文件。所有这些都支持两个平台。主机环境和嵌入式系统MSP432。
我正在学习有关嵌入式系统的入门课程，并做了几天前与之抗衡的作业。我自己尝试着通过互联网阅读，也在stackoverflow中阅读了这篇文章，但我还没明白，我仍然是一个菜鸟，所以我希望有人可以向我解释或给我一些有关解决问题的提示
如前所述，构建系统必须支持这两个平台，因此，第一步，我着重于确保所有工作都适用于主机环境。
build-生成可执行文件，目标文件，依赖项文件和映射文件%.o: %.c ...-生成目标文件及其依赖项compile-all-编译所有对象，但不链接它们%.i: %.c-生成C源文件的预处理输出%.asm: %.C-生成C源文件的程序集输出clean-清除所有生成的文件make build PLATFORM=HOST 运行命令，我们得到：
.../src$ sudo make build PLATFORM=HOST
gcc -Wall -Werror -g -std=c99 -DHOST -Wl,-O0,-Map=c1m2.map main.c memory.c -I../includes/common -o c1m2.out
make: *** No rule to make target 'main.o', needed by 'build'. Stop.
我注意到出现错误是因为第132行是我们
%.o: %.c
此行旨在禁用内置规则，并使用用户定义的下一行来的规则，但并没有这样做，因此我尝试注释此行并再次执行构建，然后得到：
.../src$ sudo make build PLATFORM=HOST
gcc -Wall -Werror -g -std=c99 -DHOST -Wl,-O0,-Map=c1m2.map main.c memory.c -I../includes/common -o c1m2.out
gcc -Wall -Werror -g -std=c99 -DHOST -E -c -o main.o main.c
main.c:23:22: fatal error: platform.h: No such file or directory
compilation terminated.
< builtin >: recipe for target 'main.o' failed
make: *** [main.o] Error 1
现在它说，尽管包含包含头文件位置的INCLUDES变量指示它找不到“ platform.h”。另外，它使用内置配方来生成目标文件，并且失败。
因此，我被困在这一点上，想法是在执行“ make build PLATFORM = HOST”时构建输出可执行文件，映射文件，目标文件及其依赖文件。
在一开始，我编写了生成目标文件，仅用于生成输出，地图和目标文件，并且确实起作用，然后在进行了修改以生成依赖项文件后，我因该错误而迷失了方向。
生成预先处理的文件，程序集文件和进行清理的其他方法都可以正常工作。
谢谢大家。
这是我的Makefile：
#******************************************************************************
# Copyright (C) 2017 by Alex Fosdick - University of Colorado
#
# Redistribution, modification or use of this software in source or binary
# forms is permitted as long as the files maintain this copyright. Users are
# permitted to modify this and use it to learn about the field of embedded
# software. Alex Fosdick and the University of Colorado are not liable for any
# misuse of this material.
#
#******************************************************************************
# Modified on April 2020 by Adrián Fornaso
#------------------------------------------------------------------------------
# Simple Makefile for multitarget build system
#
# Use: make [TARGET] [PLATFORM-OVERRIDES]
#
# Build Targets:
#
# build - Builds and links all source files and genereates:
#
# c1m2.map - Map file for the full build
# *.d - Dependency Files for each source file
# *.o - Individual object files
# c1m2.out - Output Executable file
#
#<FILE>.i - Builds <FILE>.i preprocessed file.
#<FILE>.asm - Builds <FILE>.i assembly file.
#<FILE>.o - Builds <FILE>.o object file.
#compile-all - Compile all objects but do NOT link them.
#clean - Removes all generated files.
#
# Platform Overrides: Conditionally assign the appropriate compiler flags,
# linker flags, and architecture flags. The target platform
# must be provided at the command line with the make
# command to set the platform you are compiling for.
#
# PLATFORM = MSP432 - The target embedded system will use
# the cross compiler, arm-none-eabi-gcc.
# PLATFORM = HOST - The host embedded system will use the
# native compiler, gcc.
#
#------------------------------------------------------------------------------
#------------------------------------------------------------------------------
#General Flags (Both Platforms)
#
# -Wall Enable All Warning Messages (CFLAGS)
# -Werror Treats All Warnings as Errors(CFLAGS)
# -g Generate Debugging Info in Executable (CFLAGS)
# -O0 The level of optimization (-O0, -O1, -O2, -O3)) (LDFLAGS)
# -std=c99 The C standard set (CFLAGS)
#
#------------------------------------------------------------------------------
#Target name
BASENAME = c1m2
TARGET = $(BASENAME).out
#General Flags
COMMONCFLAGS = -Wall -Werror -g -std=c99
COMMONLDFLAGS = -Wl,-O0,-Map=$(BASENAME).map
#No spaces after commas after -Wl option.
CPPFLAGS = -E
# -E flag makes the compiler stop in the preprocessed output
#Compile time switches
ifeq ($(PLATFORM), MSP432)
INCLUDES = -I../includes/common \
-I../includes/msp432 \
-I../includes/CMSIS
SOURCES = main.c \
memory.c \
interrupts_msp432p401r_gcc.c \
startup_msp432p401r_gcc.c \
system_msp432p401r.c
LINKER_FILE = msp432p401r.lds
CPU = cortex-m4
ARCH = armv7e-m
SPECS = nosys.specs
CC = arm-none-eabi-gcc
LD = arm-none-eabi-ld
LDFLAGS = $(COMMONLDFLAGS), -T=$(LINKER_FILE)
CFLAGS = $(COMMONCFLAGS) -D$(PLATFORM) -mcpu=$(CPU) \
-march=$(ARCH) --specs=$(SPECS)
OBJDUMP = arm-none-eabi-objdump
endif
ifeq ($(PLATFORM), HOST)
INCLUDES = -I../includes/common
SOURCES = main.c \
memory.c
CC = gcc
LD = ld
LDFLAGS = $(COMMONLDFLAGS)
CFLAGS = $(COMMONCFLAGS) -D$(PLATFORM)
OBJDUMP = objdump
endif
#Listing object files:
OBJECTS = $(SOURCES:.c=.o)
# 1. --------------------------------------------------------------------------
# Complete build: c1m2.map - Map file for the full build
# *.d - Dependency Files for each source file
# *.o - Individual object files
# c1m2.out - Output Executable file
# LDFLAGS contains the flags for creating the *.map file
.PHONY: build
build: $(TARGET) $(OBJECTS)
$(TARGET):
$(CC) $(CFLAGS) $(LDFLAGS) $(SOURCES) $(INCLUDES) -o $@
# 2. --------------------------------------------------------------------------
# //// Generates the object files of all c-program implementation files and its
# dependecies. ///////////////////////////////////////////////////////////
#This implementation places dependency files into a subdirectory named .deps.
DEPDIR := .deps
DEPFLAGS = -MT $@ -MD -MP -MF $(DEPDIR)/$*.d
# Delete the built-in rules for building object files from .c files, so that
# our rule is used instead.
#%.o: %.c
# Our rule for building object files with its dependency
%.o: %.c $(DEPDIR)/%.d | $(DEPDIR)
$(CC) $(DEPFLAGS) -c $(CFLAGS) $(INCLUDES) -o $@ $^
# Declare a rule for creating the dependency directory if it doesn’t exist.
$(DEPDIR): ; @mkdir -p $@
# Generate a list of all the dependency files that could exist.
DEPFILES := $(SRCS:%.c=$(DEPDIR)/%.d)
# Mention each dependency file as a target, so that make won’t fail if the file
# doesn’t exist.
$(DEPFILES):
# 2 bis. ----------------------------------------------------------------------
# /// Generates the object file of all c-program implementation files. ////////
#%.o: %.c
# $(CC) -c $(CFLAGS) $(INCLUDES) -o $@ $^
# 3. --------------------------------------------------------------------------
# /// Compile all objects but do NOT link them. ///////////////////////////////
.PHONY: compile-all
compile-all: $(SOURCES)
$(CC) -c $(CFLAGS) $(INCLUDES) $^
# 4. --------------------------------------------------------------------------
# /// Generates the preprocessed output of all c-program implementation files.
%.i: %.c
$(CC) $(CPPFLAGS) $(CFLAGS) $(INCLUDES) -o $@ $^
# 5. --------------------------------------------------------------------------
# /// Create assembler file of a C source. ////////////////////////////////////
%.asm: %.c
$(CC) -S $(CFLAGS) $(INCLUDES) $< -o $@
# -S flag tells the compiler just generate the assembly file
# 6. --------------------------------------------------------------------------
# /// Removes all compiled objects, preprocessed outputs, assembly outputs,
# executable files and build output files. ////////////////////////////////
.PHONY: clean
clean:
rm -f $(OBJECTS) $(TARGET) $(BASENAME).map *.asm *.i
rm -r .dep
#End of file
答案 0 :(得分：1)
有两个小错误使我花了相当长时间才能看到：
DEPFILES := $(SRCS:%.c=$(DEPDIR)/%.d)必须为DEPFILES := $(SOURCES:%.c=$(DEPDIR)/%.d)-否则DEPFILES为空，因为SRCS未定义。$(CC) $(DEPFLAGS) -c $(CFLAGS) $(INCLUDES) -o $@ $^中，$^（所有先决条件）扩展为e。 G。 main.c .deps/main.d，因此将尚不存在的.deps/main.d作为输入文件传递；我们希望使用$*.c而不是$^。另一个小错误是：
rm -r .dep应该是rm -r .deps或rm -r $(DEPDIR)。