http://blog.csdn.net/mr_raptor/article/details/7540066
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http://blog.csdn.net/mr_raptor/article/details/7540066
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Android编译系统详解(一):http://blog.csdn.net/mr_raptor/article/details/7539978
Android编译系统详解(二):http://blog.csdn.net/mr_raptor/article/details/7540066
Android编译系统详解(三):http://blog.csdn.net/mr_raptor/article/details/7540730
通过上篇文章,我们分析了编译android时source build/envsetup.sh和lunch命令,在执行完上述两个命令后, 我们就可以进行编译android了。
1. make
执行make命令的结果就是去执行当前目录下的Makefile文件,我们来看下它的内容:
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1 ### DO NOT EDIT THIS FILE ###
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2 include build/core/main.mk
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3 ### DO NOT EDIT THIS FILE ###
呵呵,看到上面 的内容,我们都会笑,这是我见过最简单的Makefile了,我们再看下build/core/main.mk
main.mk文件里虽然脚本不多,但是却定义了整个Android的编译关系,它主要引入了下列几个重要的mk文件:
49 include $(BUILD_SYSTEM)/config.mk
55 include $(BUILD_SYSTEM)/cleanbuild.mk
142 include $(BUILD_SYSTEM)/definitions.mk
当然每个mk文件都有自己独特的意义,我一并将主线流程通过下面这个图各表现出来,先有个整体的概念,然后再细化了解。
所有的Makefile都通过build/core/main.mk这个文件组织在一起,它定义了一个默认goals:droid,当我们在TOP目录下,敲Make实际上就等同于我们执行make droid。
当Make include所有的文件,完成对所有make我文件的解析以后就会寻找生成droid的规则,依次生成它的依赖,直到所有满足的模块被编译好,然后使用相应的工具打包成相应的img。其中,config.mk,envsetup.mk,product_config.mk文件是编译用户指定平台系统的关键文件。上图中红色部分是用户指定平台产品的编译主线,我们先来看下config.mk的主要作用。
2. build/core/config.mk
该文件被main.mk包含。
定义了以下环境变量:
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16 SRC_HEADERS := \
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17 $(TOPDIR)system/core/include \
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18 $(TOPDIR)hardware/libhardware/include \
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19 $(TOPDIR)hardware/libhardware_legacy/include \
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20 $(TOPDIR)hardware/ril/include \
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21 $(TOPDIR)dalvik/libnativehelper/include \
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22 $(TOPDIR)frameworks/base/include \
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23 $(TOPDIR)frameworks/base/opengl/include \
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24 $(TOPDIR)external/skia/include
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25 SRC_HOST_HEADERS:=$(TOPDIR)tools/include
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26 SRC_LIBRARIES:= $(TOPDIR)libs
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27 SRC_SERVERS:= $(TOPDIR)servers
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28 SRC_TARGET_DIR := $(TOPDIR)build/target
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29 SRC_API_DIR := $(TOPDIR)frameworks/base/api
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43 CLEAR_VARS:= $(BUILD_SYSTEM)/clear_vars.mk
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44 BUILD_HOST_STATIC_LIBRARY:= $(BUILD_SYSTEM)/host_static_library.mk
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45 BUILD_HOST_SHARED_LIBRARY:= $(BUILD_SYSTEM)/host_shared_library.mk
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46 BUILD_STATIC_LIBRARY:= $(BUILD_SYSTEM)/static_library.mk
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47 BUILD_RAW_STATIC_LIBRARY := $(BUILD_SYSTEM)/raw_static_library.mk
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48 BUILD_SHARED_LIBRARY:= $(BUILD_SYSTEM)/shared_library.mk
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49 BUILD_EXECUTABLE:= $(BUILD_SYSTEM)/executable.mk
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50 BUILD_RAW_EXECUTABLE:= $(BUILD_SYSTEM)/raw_executable.mk
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51 BUILD_HOST_EXECUTABLE:= $(BUILD_SYSTEM)/host_executable.mk
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52 BUILD_PACKAGE:= $(BUILD_SYSTEM)/package.mk
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53 BUILD_HOST_PREBUILT:= $(BUILD_SYSTEM)/host_prebuilt.mk
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54 BUILD_PREBUILT:= $(BUILD_SYSTEM)/prebuilt.mk
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55 BUILD_MULTI_PREBUILT:= $(BUILD_SYSTEM)/multi_prebuilt.mk
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56 BUILD_JAVA_LIBRARY:= $(BUILD_SYSTEM)/java_library.mk
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57 BUILD_STATIC_JAVA_LIBRARY:= $(BUILD_SYSTEM)/static_java_library.mk
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58 BUILD_HOST_JAVA_LIBRARY:= $(BUILD_SYSTEM)/host_java_library.mk
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59 BUILD_DROIDDOC:= $(BUILD_SYSTEM)/droiddoc.mk
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60 BUILD_COPY_HEADERS := $(BUILD_SYSTEM)/copy_headers.mk
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61 BUILD_KEY_CHAR_MAP := $(BUILD_SYSTEM)/key_char_map.mk
上述命令变量其实是对应的mk文件名,几乎所有的Android.mk文件里基本上都包含上述命令变量,如:
CLEAR_VARS:用来清除之前定义的环境变量
BUILD_SHARED_LIBRARY:用来指定编译动态库过程
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109 # ---------------------------------------------------------------
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110 # Define most of the global variables. These are the ones that
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111 # are specific to the user's build configuration.
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### evnsetup.mk文件里定义了大部分的全局变量,用户使用这些变量来编译系统
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112 include $(BUILD_SYSTEM)/envsetup.mk
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113
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114 # Boards may be defined under $(SRC_TARGET_DIR)/board/$(TARGET_DEVICE)
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115 # or under vendor/*/$(TARGET_DEVICE). Search in both places, but
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116 # make sure only one exists.
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117 # Real boards should always be associated with an OEM vendor.
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### 板级配置信息通常定义在$(SRC_TARGET_DIR)/board/$(TARGET_DEVICE)或vendor/*/$(TARGET_DEVICE)下面,从这两个地方搜索,但是只能有一个地方存在板级配置信息(TARGET_DEVICE变量在上面的envsetup.mk里定义)
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-
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### wildcard命令用于在某个目录下查找匹配的文件,将找到的文件列表返回
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118 board_config_mk := \
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119 $(strip $(wildcard \
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120 $(SRC_TARGET_DIR)/board/$(TARGET_DEVICE)/BoardConfig.mk \
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121 vendor/*/$(TARGET_DEVICE)/BoardConfig.mk \
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122 ))
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### 如果没有找到,提示出错
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123 ifeq ($(board_config_mk),)
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124 $(error No config file found for TARGET_DEVICE $(TARGET_DEVICE))
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125 endif
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### 如果找到了1个以上时,提示出错
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126 ifneq ($(words $(board_config_mk)),1)
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127 $(error Multiple board config files for TARGET_DEVICE $(TARGET_DEVICE): $(board_config_mk))
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128 endif
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129 include $(board_config_mk) # 将板级配置信息包含进来
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130 TARGET_DEVICE_DIR := $(patsubst %/,%,$(dir $(board_config_mk)))
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131 board_config_mk :=
112行又包含了另外一个重要的mk文件envsetup.mk,我们来看一下。
3. envsetup.mk
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25 ifeq ($(TARGET_PRODUCT),) # 如果TARGET_PRODUCT为空
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26 ifeq ($(TARGET_SIMULATOR),true) # 编译为模拟器
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27 TARGET_PRODUCT := sim
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28 else
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29 TARGET_PRODUCT := generic # 默认产品名字为generic
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30 endif
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31 endif
第25行,判断TARGET_PRODUCT是否为空,根据上一节分析可知,TARGET_PRODUCT=fs100
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34 # the variant -- the set of files that are included for a build
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35 ifeq ($(strip $(TARGET_BUILD_VARIANT)),) # 如果编译版本型号变量为空
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36 TARGET_BUILD_VARIANT := eng
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37 endif
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38
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39 # Read the product specs so we an get TARGET_DEVICE and other
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40 # variables that we need in order to locate the output files.
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## product_config.mk文件,读取产品配置信息,从而得到目标设备,将其导出到TARGET_DEVICE变量里,后面的定义的OUT变量的值,也依赖于目标设备TARGET_DEVICE,用于指定目标代码的输出目录
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41 include $(BUILD_SYSTEM)/product_config.mk
在41行又包含了product_config.mk文件,等会我们再分析它,先看下面的
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148 # ---------------------------------------------------------------
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149 # figure out the output directories
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150
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151 ifeq (,$(strip $(OUT_DIR)))
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152 OUT_DIR := $(TOPDIR)out
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153 endif
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154
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155 DEBUG_OUT_DIR := $(OUT_DIR)/debug
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156
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157 # Move the host or target under the debug/ directory
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158 # if necessary.
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159 TARGET_OUT_ROOT_release := $(OUT_DIR)/target
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160 TARGET_OUT_ROOT_debug := $(DEBUG_OUT_DIR)/target
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161 TARGET_OUT_ROOT := $(TARGET_OUT_ROOT_$(TARGET_BUILD_TYPE))
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162
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...
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### 这个重要的OUT变量,依赖于目标设备名TARGET_DEVICE
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184 PRODUCT_OUT := $(TARGET_PRODUCT_OUT_ROOT)/$(TARGET_DEVICE)
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187
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188 HOST_OUT_EXECUTABLES:= $(HOST_OUT)/bin
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189 HOST_OUT_SHARED_LIBRARIES:= $(HOST_OUT)/lib
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?190 HOST_OUT_JAVA_LIBRARIES:= $(HOST_OUT)/framework
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191 HOST_OUT_SDK_ADDON := $(HOST_OUT)/sdk_addon
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...
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200 TARGET_OUT_INTERMEDIATES := $(PRODUCT_OUT)/obj
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201 TARGET_OUT_HEADERS:= $(TARGET_OUT_INTERMEDIATES)/include
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202 TARGET_OUT_INTERMEDIATE_LIBRARIES := $(TARGET_OUT_INTERMEDIATES)/lib
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203 TARGET_OUT_COMMON_INTERMEDIATES := $(TARGET_COMMON_OUT_ROOT)/obj
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204
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### 后面的OUT变量都要间接依赖于TARGET_DEVICE
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205 TARGET_OUT := PRODUCT_OUT)/system
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206 TARGET_OUT_EXECUTABLES:= $(TARGET_OUT)/bin
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207 TARGET_OUT_OPTIONAL_EXECUTABLES:= $(TARGET_OUT)/xbin
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208 TARGET_OUT_SHARED_LIBRARIES:= $(TARGET_OUT)/lib
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209 TARGET_OUT_JAVA_LIBRARIES:= $(TARGET_OUT)/framework
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210 TARGET_OUT_APPS:= $(TARGET_OUT)/app
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211 TARGET_OUT_KEYLAYOUT := $(TARGET_OUT)/usr/keylayout
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212 TARGET_OUT_KEYCHARS := $(TARGET_OUT)/usr/keychars
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213 TARGET_OUT_ETC := $(TARGET_OUT)/etc
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214 TARGET_OUT_STATIC_LIBRARIES:= $(TARGET_OUT_INTERMEDIATES)/lib
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215 TARGET_OUT_NOTICE_FILES:=$(TARGET_OUT_INTERMEDIATES)/NOTICE_FILES
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216
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217 TARGET_OUT_DATA := $(PRODUCT_OUT)/data
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218 TARGET_OUT_DATA_EXECUTABLES:= $(TARGET_OUT_EXECUTABLES)
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219 TARGET_OUT_DATA_SHARED_LIBRARIES:= $(TARGET_OUT_SHARED_LIBRARIES)
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220 TARGET_OUT_DATA_JAVA_LIBRARIES:= $(TARGET_OUT_JAVA_LIBRARIES)
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221 TARGET_OUT_DATA_APPS:= $(TARGET_OUT_DATA)/app
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222 TARGET_OUT_DATA_KEYLAYOUT := $(TARGET_OUT_KEYLAYOUT)
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223 TARGET_OUT_DATA_KEYCHARS := $(TARGET_OUT_KEYCHARS)
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224 TARGET_OUT_DATA_ETC := $(TARGET_OUT_ETC)
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225 TARGET_OUT_DATA_STATIC_LIBRARIES:= $(TARGET_OUT_STATIC_LIBRARIES)
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226
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227 TARGET_OUT_UNSTRIPPED := $(PRODUCT_OUT)/symbols
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228 TARGET_OUT_EXECUTABLES_UNSTRIPPED := $(TARGET_OUT_UNSTRIPPED)/system/bin
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229 TARGET_OUT_SHARED_LIBRARIES_UNSTRIPPED := $(TARGET_OUT_UNSTRIPPED)/system/lib
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230 TARGET_ROOT_OUT_UNSTRIPPED := $(TARGET_OUT_UNSTRIPPED)
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231 TARGET_ROOT_OUT_SBIN_UNSTRIPPED := $(TARGET_OUT_UNSTRIPPED)/sbin
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232 TARGET_ROOT_OUT_BIN_UNSTRIPPED := $(TARGET_OUT_UNSTRIPPED)/bin
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233
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234 TARGET_ROOT_OUT := $(PRODUCT_OUT)/root
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235 TARGET_ROOT_OUT_BIN := $(TARGET_ROOT_OUT)/bin
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236 TARGET_ROOT_OUT_SBIN := $(TARGET_ROOT_OUT)/sbin
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237 TARGET_ROOT_OUT_ETC := $(TARGET_ROOT_OUT)/etc
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238 TARGET_ROOT_OUT_USR := $(TARGET_ROOT_OUT)/usr
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239
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240 TARGET_RECOVERY_OUT := $(PRODUCT_OUT)/recovery
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241 TARGET_RECOVERY_ROOT_OUT := $(TARGET_RECOVERY_OUT)/root
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242
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243 TARGET_SYSLOADER_OUT := $(PRODUCT_OUT)/sysloader
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244 TARGET_SYSLOADER_ROOT_OUT := $(TARGET_SYSLOADER_OUT)/root
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245 TARGET_SYSLOADER_SYSTEM_OUT := $(TARGET_SYSLOADER_OUT)/root/system
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246
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247 TARGET_INSTALLER_OUT := $(PRODUCT_OUT)/installer
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248 TARGET_INSTALLER_DATA_OUT := $(TARGET_INSTALLER_OUT)/data
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249 TARGET_INSTALLER_ROOT_OUT := $(TARGET_INSTALLER_OUT)/root
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250 TARGET_INSTALLER_SYSTEM_OUT := $(TARGET_INSTALLER_OUT)/root/system
上面的代码是指定了目标输出代码的位置和主机输出代码的位置,重要的几个如下:
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TARGET_OUT = $(PRODUCT_OUT)/system
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TARGET_OUT_EXECUTABLES = $(PRODUCT_OUT)/system/bin
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TARGET_OUT_SHARED_LIBRARIES = $(PRODUCT_OUT)/system/lib
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TARGET_OUT_JAVA_LIBRARIES = $(PRODUCT_OUT)/system/framework
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TARGET_OUT_APPS = $(PRODUCT_OUT)/system/app
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TARGET_OUT_ETC = $(PRODUCT_OUT)/system/etc
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TARGET_OUT_STATIC_LIBRARIES = $(PRODUCT_OUT)/obj/lib
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TARGET_OUT_DATA = $(PRODUCT_OUT)/data
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TARGET_OUT_DATA_APPS = $(PRODUCT_OUT)/data/app
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TARGET_ROOT_OUT = $(PRODUCT_OUT)/root
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TARGET_ROOT_OUT_BIN = $(PRODUCT_OUT)/bin
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TARGET_ROOT_OUT_SBIN = $(PRODUCT_OUT)/system/sbin
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TARGET_ROOT_OUT_ETC = $(PRODUCT_OUT)/system/etc
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TARGET_ROOT_OUT_USR = $(PRODUCT_OUT)/system/usr
总结下:
envsetup.mk文件主要包含了product_config.mk文件,然后指定了编译时要输出的所有文件的OUT目录,这些OUT目录变量依赖于TARGET_DEVICE变量。
4. build/core/product_config.mk
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157 include $(BUILD_SYSTEM)/product.mk
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...
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160 # Read in all of the product definitions specified by the AndroidProducts.mk
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161 # files in the tree.
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162 #
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163 #TODO: when we start allowing direct pointers to product files,
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164 # guarantee that they're in this list.
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165 $(call import-products, $(get-all-product-makefiles))
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166 $(check-all-products)
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...
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170 # Convert a short name like "sooner" into the path to the product
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171 # file defining that product.
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172 #
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173 INTERNAL_PRODUCT := $(call resolve-short-product-name, $(TARGET_PRODUCT))
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...
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176 # Find the device that this product maps to.
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177 TARGET_DEVICE := $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_DEVICE)
157行,我靠,又包含了product.mk文件
165行,调用函数import-products, $(get-all-product-makefiles),这儿我们看上面的注释:
Read in all of the product definitions specified by the AndroidProducts.mk files in the tree.
TODO: when we start allowing direct pointers to product files, guarantee that they're in this list.
意思是说:读取厂商目录下(vendor/*/products/AndroidProducts.mk)所有的AndrodProducts.mk文件中定义的产品信息
其实get-all-product-makefiles返回厂商全部产品文件xxx.mk
import-products函数去验证这些产品配置文件是否都包含有必须的配置信息,细节后面分析。
173行调用了resolve-short-product-name函数,它将根据产品TARGET_PRODUCT,返回该产品配置文件的完整路径,并赋给INTERNAL_PRODUCT
例如TARGET_PRODUCT=fs100,则:
INTERNAL_PRODUCT = vendor/farsight/products/fs100.mk
TARGET_DEVICE = fs100
如果调试看其结果,可以在167行,将#$(dump-product)取消注释
然后在175行添加: $(info $(INTERNAL_PRODUCT))
在178行添加: $(info $(TARGET_DEVICE )),查看调试结果。
总结一下:
接合前面的图,product_config.mk主要读取vendor目录下不同厂商自己定义的AndrodProducts.mk文件(vendor/*/products/AndroidProducts.mk),从该文件里取得所有产品的配置文件,然后再根据lunch选择的编译项TARGET_PRODUCT,找到与之对应的配置文件,然后读取产品配置文件,找到里面的PRODUCT_DEVICE的值,设置给TARGET_DEVICE变量,用于后续编译。
5. build/core/product.mk
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17 #
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18 # Functions for including AndroidProducts.mk files
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19 #
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20
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21 #
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22 # Returns the list of all AndroidProducts.mk files.
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23 # $(call ) isn't necessary.
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24 #
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25 define _find-android-products-files
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26 $(shell test -d vendor && find vendor -maxdepth 6 -name AndroidProducts.mk) \
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27 $(SRC_TARGET_DIR)/product/AndroidProducts.mk
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28 endef
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29
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30 #
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31 # Returns the sorted concatenation of all PRODUCT_MAKEFILES
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32 # variables set in all AndroidProducts.mk files.
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33 # $(call ) isn't necessary.
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34 #
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35 define get-all-product-makefiles
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36 $(sort \
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37 $(foreach f,$(_find-android-products-files), \
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38 $(eval PRODUCT_MAKEFILES :=) \
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39 $(eval LOCAL_DIR := $(patsubst %/,%,$(dir $(f)))) \
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40 $(eval include $(f)) \
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41 $(PRODUCT_MAKEFILES) \
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42 ) \
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43 $(eval PRODUCT_MAKEFILES :=) \
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44 $(eval LOCAL_DIR :=) \
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45 )
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46 endef
通过注释可知,本文件中主要是一些用来处理AndroidProduct.mk的函数
_find-android-products-files:
用来获得vendor目录下,所有名字为AndroidProduct.mk的文件列表。
get-all-product-makefiles:
用来获得所有AndroidProduct.mk文件里定义的PRODUCT_MAKEFILES的值(其实是产品文件路径名)。
在vendor目录下,每个厂商子目录下都会存在一个AndroidProduct.mk文件,这个文件是用来定义这个厂商的产品列表,每个产品用.mk来表示
如Android给的示例:
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vendor/sample/products/AndroidProduct.mk
其内容如下:
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1 #
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2 # This file should set PRODUCT_MAKEFILES to a list of product makefiles
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3 # to expose to the build system. LOCAL_DIR will already be set to
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4 # the directory containing this file.
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5 #
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6 # This file may not rely on the value of any variable other than
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7 # LOCAL_DIR; do not use any conditionals, and do not look up the
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8 # value of any variable that isn't set in this file or in a file that
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9 # it includes.
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10 #
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11
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12 PRODUCT_MAKEFILES := \
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13 $(LOCAL_DIR)/sample_addon.mk
里面只定义了一个产品配置文件,即当前目录下的sample_addon.mk:
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1 # List of apps and optional libraries (Java and native) to put in the add-on system image.
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2 PRODUCT_PACKAGES := \
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3 PlatformLibraryClient \
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4 com.example.android.platform_library \
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5 libplatform_library_jni
上述文件里(sample_addon.mk)定义了产品相关个性化信息,如,PRODUCT_PACKAGES表示要在当前产品里添加一些安装包。
由此可见,get-all-product-makefiles函数,其实就是返回了当前公司里全部的产品对应的mk文件列表。
总结:
如果用户想个性定制自己的产品,应该有以下流程,包含上一节内容:
注:#表示shell提示符
1. 创建厂商目录
#mkdir vendor/farsight
2. 创建一个vendorsetup.sh文件,将当前产品编译项添加到lunch里,让lunch能找到用户产品编译项
#echo "add_lunch_combo fs100-eng" > vendor/farsight/vendorsetup.sh
注:我们增加一个用户产品编译项,fs100-eng
3. 仿着Android示例代码,在厂商目录下创建products目录
#mkdir -p vendor/farsight/products
4. 仿着Android示例代码,在products目录下创建两个mk文件
#touch vendor/farsight/products/AndroidProduct.mk vendor/farsight/products/fs100.mk
注:其中AndroidProduct.mk是当前厂商产品列表文件,fs100.mk表示当前厂商的一款产品配置文件
在AndroidProduct.mk里添加如下内容:
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PRODUCT_MAKEFILES := $(LOCAL_DIR)/fs100.mk
注:表示只有一个产品fs100,它对应的配置文件在当前目录下的fs100.mk。
5. 在产品配置文件里添加最基本信息
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1
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2 PRODUCT_PACKAGES := \
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3 IM \
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4 VoiceDialer
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5
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6 $(call inherit-product, build/target/product/generic.mk) ##从某一默认配置开始派生余下内容参考派生起点
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7
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8 # Overrides
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9 PRODUCT_MANUFACTURER := farsight
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10 PRODUCT_NAME := fs100
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11 PRODUCT_DEVICE := fs100
一定要注意:
PRODUCT_NAME:表示产品名字,它要和最终出现的编译项产品名一致,也就是说fs100-eng
PRODUCT_DEVICE:表示设备名字,它要和将来创建的设备目录名字一致。
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