Makefile研究 —— 实际应用

Posted 2020-10-09 西门吹雪~~~

转自：http://blog.csdn.net/jundic/article/details/17886637

前面讲了Makefile 的简单语法和简单的应用模板，但在实际项目应用中比这个肯定复杂很多，但是我想说他的Makefile应用模式都是大同小异，只是代码量和工程复杂度大写而已。

我觉得一个完整的工程目录应该这样：

1、工程文件结构目录应该要非常清晰，并且模块化，各个模块下的Makefile 独立

2、可以分别单独编译各个单独模块成.a 或.so

3、在顶层目录下可以一次性生成可执行文件。

现在我搭建了如下工程目录

 

build为编译产生的结果文件，out 为可执行bin文件，libs为生成的库

project 为工程文件夹，下面有module1 、module2 、module3三个模块，main.c 为主函数它将生成可执行文件，虚线框为编译时生成的文件夹或文件

module2 module3和module1的文件结构相同图中没有画出来。

现进行如下分工，module1 module2 将产生静态库到 build/libs/static 中，module3将产生动态库到 build/libs/dynamic 中，最后main.c 将调用这些库编译生成可执行文件到

build/out 中。

为了提高模块的复用性，我们会在顶层目录下，写一个rules.mk文件，事实上很多项目是这么做的比如uboot 。

rules.mk 代码

  1 # rules .mk  
  2   
  3 # Generic Makefile for C/C++ Program  
  4 # Author:   
  5 # Description: # ------------  
  6 # This is an easily customizable makefile template. The purpose is to  
  7 # provide an instant building environment for C/C++ programs.  
  8 #  
  9 # It searches all the C/C++ source files in the specified directories,  
 10 # makes dependencies, compiles and links to form an executable.  
 11 #  
 12 # Besides its default ability to build C/C++ programs which use only  
 13 # standard C/C++ libraries, you can customize the Makefile to build  
 14 # those using other libraries. Once done, without any changes you can  
 15 # then build programs using the same or less libraries, even if source  
 16 # files are renamed, added or removed. Therefore, it is particularly  
 17 # convenient to use it to build codes for experimental or study use.  
 18 #  
 19 # GNU make is expected to use the Makefile. Other versions of makes  
 20 #  
 21   
 22 .PHONY : all clean  
 23   
 24 # Top directory  Makefile  
 25   
 26 # The C program compiler  
 27 CC = gcc  
 28 MACRO = DEBUGALL  
 29 CFLAGS += -g -werror -D$(MACRO)  
 30 AR = ar  
 31 ARFLAGES = crv  
 32   
 33 # default execute output directory  
 34 ifeq ($(DIR_EXES),)  
 35 DIR_EXES = $(TOPDIR)/build/out  
 36 endif  
 37   
 38 # defaulet libaray creat directory  
 39 ifeq ($(DIR_LIBS),)  
 40 DIR_LIBS = $(TOPDIR)/build/libs  
 41 endif  
 42   
 43 # directory  
 44 DIRS = $(DIR_OBJS) $(DIR_DEPS) $(DIR_EXES) $(DIR_LIBS)  
 45   
 46 # include directory   
 47 ifneq ($(DIR_INCS),"")  
 48 DIR_INCS := $(strip $(DIR_INCS))  
 49 DIR_INCS := $(addprefix -I,$(DIR_INCS))  
 50 endif  
 51   
 52 # when build execute file   
 53 ifneq ($(EXES),)  
 54 EXES := $(addprefix $(DIR_EXES)/,$(EXES))  
 55 RMS += $(EXES)  
 56 DIR_LIBS := $(strip $(DIR_LIBS))  
 57 DIR_LIBS := $(addprefix -L,$(DIR_LIBS))  
 58 endif  
 59   
 60 # when build static libaray file   
 61 ifneq ($(LIBS),"")  
 62 LIBS := $(addprefix $(DIR_LIBS)/,$(LIBS))  
 63 RMS += $(LIBS)  
 64 endif  
 65   
 66 # default source code file directory  
 67 ifeq ($(DIR_SRCS),)  
 68 DIR_SRCS = .  
 69 endif  
 70 SRCS = $(wildcard $(DIR_SRCS)/*.c)  
 71 OBJS = $(patsubst %.c, %.o,$(notdir $(SRCS)))  
 72 OBJS := $(addprefix $(DIR_OBJS)/,$(OBJS))  
 73 RMS += $(OBJS) $(DIR_OBJS)  
 74   
 75 DEPS = $(patsubst %.c, %.dep,$(notdir $(SRCS)))  
 76 DEPS := $(addprefix $(DIR_DEPS)/,$(DEPS))  
 77 RMS += $(DEPS) $(DIR_DEPS)  
 78   
 79 ifneq ($(EXES),"")  
 80 all : $(EXES)  
 81 endif  
 82   
 83 ifneq ($(LIBS),"")  
 84 all : $(LIBS)  
 85 endif  
 86   
 87 ifneq ($(LINK_LIBS),"")  
 88 LINK_LIBS := $(strip $(LINK_LIBS))  
 89 LINK_LIBS := $(addprefix -l,$(LINK_LIBS))  
 90 endif  
 91   
 92 # include dependent files   
 93 ifneq ($(MAKECMDGOALS), clean)  
 94 -include $(DEPS)  
 95 endif   
 96   
 97 $(DIRS):  
 98     mkdir -p [email protected]  
 99   
100 # creat execute file  
101 $(EXES) : $(DIR_OBJS) $(OBJS) $(DIR_EXES)  
102     $(CC) $(DIR_INCS) $(CFLAGES) -o [email protected] $(OBJS) $(DIR_LIBS) $(LINK_LIBS)  
103   
104 # creat libaray file  
105 $(LIBS) : $(DIR_LIBS) $(DIR_OBJS) $(OBJS)  
106 # library type is static  
107 ifeq ($(LIB_TYPE),static)  
108     $(AR) $(ARFLAGS) [email protected] $(OBJS)  
109 endif  
110   
111 # library type is dynamic  
112 ifeq ($(LIB_TYPE),dynamic)  
113     $(CC) -shared -o [email protected] $(OBJS)  
114 endif  
115   
116 # creat object file   
117 $(DIR_OBJS)/%.o : $(DIR_SRCS)/%.c  
118     @echo "source files:" $<  
119     @echo "object files:" [email protected]  
120 ifeq ($(LIB_TYPE),static)  
121     $(CC) $(DIR_INCS) $(CFLAGES) -o [email protected] -c $<  
122 else  
123     $(CC) $(DIR_INCS) $(CFLAGES) -fPIC -o [email protected] -c $<  
124 endif  
125   
126 # creat depandant file  
127 $(DIR_DEPS)/%.dep : $(DIR_SRCS)/%.c $(DIR_DEPS)  
128     @echo "creating depend file ..." [email protected]  
129     @set -e;\  
130     $(CC) $(DIR_INCS) -MM $< > [email protected];\  
131     sed ‘s,$?\.o[ :]*,$(DIR_OBJS)/\1.o [email protected] : ,g‘ < [email protected] > [email protected]  
132 #   rm [email protected]  
133   
134 clean:  
135     rm -rf $(RMS)  

这个makefile 没有什么好分析的和第二篇文章单目录工程makefile一样的。

好了进入module1 下我们想把 module1编译成libmodule1.a 对应的Makefile 就很简单啦。

 1 # module1 Makefile      
 2 DIR_CUR = $(shell pwd)  
 3 DIR_SRCS = $(DIR_CUR)/src  
 4 DIR_INCS += $(DIR_CUR)/inc  
 5 DIR_OBJS = objs  
 6 DIR_DEPS = deps  
 7 DIR_LIBS = ../../build/libs/static  
 8 # library type an name  
 9 LIB_TYPE = static  
10 LIBS = libmodule1.a  
11 # LIB_TYPE = dynamic  
12 # LIBS = libmodule1.so  
13   
14 include ../../rules.mk  

这个makefile就是要配置输出文件路径和名字然后将顶层rules.mk包含就ok啦。

同样的module2 目录下Makefile 也是一样的只要将LIBS 改为 libmodule2.a 即可。

module3 的我们想把他编译成动态库 则对应为如下

 1 # module1 Makefile      
 2 DIR_CUR = $(shell pwd)  
 3 DIR_SRCS = $(DIR_CUR)/src  
 4 DIR_INCS += $(DIR_CUR)/inc  
 5 DIR_OBJS = objs  
 6 DIR_DEPS = deps  
 7 DIR_LIBS = ../../build/libs/static  
 8 # library type an name  
 9 #LIB_TYPE = static  
10 #LIBS = libmodule3.a  
11 LIB_TYPE = dynamic  
12 LIBS = libmodule3.so  
13   
14 include ../../rules.mk  

 

在project 中要编译main.c 又要链接前面生成的三个库 那对应的Makefile 如下：

 1 # Current directory  Makefile   
 2 CURDIR = $(shell pwd)  
 3   
 4 # executable file name  
 5 EXES = justest  
 6   
 7 # head file directories  
 8 DIR_INCS = module1/inc\  
 9            module2/inc\  
10            module3/inc  
11   
12 # objs and dependant file directories  
13 DIR_OBJS = objs  
14 DIR_DEPS = deps  
15   
16 # static libraries   
17 LINK_LIBS = module1 module2 module3  
18   
19 # library file directories  
20 DIR_LIBS = $(TOPDIR)/build/libs/static\  
21            $(TOPDIR)/build/libs/dynamic  
22   
23 # include common rule makefile    
24 include ../rules.mk  

在这个makefile 只要配置生成的可执行文件的路径名，还有头文件目录，链接库的路径和名字就可以生成可执行文件了，这里也顶层的rules.mk。

当然在实际应用中可以到各个模块中去执行make 但当想一次性生成可执行文件，则还需要一个顶层Makefile 。

 1 .PHONY: all clean  
 2   
 3 # sofeware version information  
 4 VERSION = 1  
 5 PROJECT = mk_demo  
 6 SUBLEVEL = 4  
 7 YEAL = 2013  
 8 RELEASE_VERSION = $(PROJECT).$(YEAL).$(VERSION).$(SUBLEVEL)  
 9   
10 BUILD_DIRS = $(TOPDIR)/source/module1\  
11              $(TOPDIR)/source/module2\  
12              $(TOPDIR)/source/module3\  
13              $(TOPDIR)/source  
14                
15 all :  
16 #   @shell(export TOPDIR=`pwd`)  
17     @echo "version information:" $(RELEASE_VERSION)   
18     @echo "building ..."  
19     @set -e;\  
20     for dir in $(BUILD_DIRS);\  
21     do\  
22         cd $$dir && $(MAKE);\  
23     done  
24     @echo ""  
25     @echo "\33[35m [email protected]^_^@~ \33[m"  
26     @echo ""  
27     @echo "Build Completed"  
28   
29 clean:  
30     @echo "cleaning ...."  
31     for dir in $(BUILD_DIRS);\  
32     do\  
33         cd $$dir && $(MAKE) clean;\  
34     done  
35     rm -rf $(RMS)  
36     @echo ""  
37     @echo "Clean Completed"  
38   
39 version:  
40     @echo $(TOPDIR)  
41     @echo $(RELEASE_VERSION)  
42     @echo $(BUILD_DIRS)  
43     @echo $(RMS)  

这里最关键的几句代码就是

for dir in $(BUILD_DIRS)

do \

cd $$dir && $(MAKE);\

done 

在这里将进入各个模块目录下 执行make ，到这里一个稍微可以用工程makefile 工程实例，实现完了，其实只要模块划分好，还是很好理解的。我想说的时这种方法很常用，但不是唯一的，我有见过有些工程中也许并不需要每个模块都编译成库，或者说他要编译成库本身就是个很大的工程，一个模块的文件就特别多，目录结果就比较复杂这中该怎么写，先讲个思路，对应模块的Makefile 就搜索该目录下所以的Makefile 并包含进来。而子目录下的Makefile 将只将目录下需要编译的文件包含和路径包含经来就ok了，有时间也要总结下。

至此非常感谢我参考的《驾驭Makefile》，《Makefile编程》，《GCC 中文手册》