android_bulid_system_overview.txt

1.build categories:	
	1.core build framework:
	build/core/*

	build system的框架定义
	makefiles的基础
	定义bulid的进程模板
	build/core里的main.mk

		main.mk:
		包含在root目录中，作为mk的主文件(像主函数一样的存在)，对其他的mk files包含介绍，定义一些主要的make目标，比如droid，SDK等等
		definitions.mk:
		在build-system里的函数定义，例如my-dir,all-subdir-makefiles,fina-subdir-files,sign-package
		pdk_config.mk:
		PDK的配置信息管理文件
		dex_preopt.mk:
		根据之前的优化开启？jar包? 
		Makefile：
		被main.mk所包括，还有一些额外的内容由main.mk协助提供？/还是协助提供给main.mk
		$(ONE_SHOT_MAKEFILE):
		能使用mm和mmm这样的命令去指示出在一些特定路径下的makefile的文件所在路径/位置
		$(subdir_makefiels):
		包含了android.mk的众多模块/模板，通过python的脚本程序扫描获得
		help.mk：
		列出常见的make目标和他们对应的描述定义
		config.mk：
		整个build-system的配置文件，包含定义不同类型模块的常量，定义编译参数和常用/常见文件的后缀，例如.ZIP,.JAR,.APK
		路径设置通常的工具(环境变量设置?)，例如flex,e2fsck,dx,根据BoardConfig.mk来配置文件，产品和参数的关联
		
			Config.mk：
			pathmap.mk
			定义一些常量和函数去获取对应的头文件，例如“$(call include-path-for,frameworks-native)” 获取关于framework-native代码相关的头文件的path
			envsetup.mk
			配置build-system的环境变量，包括目标机器和本机，例如“TARGET_PRODUCT,HOST_OS,HOST_ARCH,TARGET_BUILD_VARIANT”
			combo/select.mk
			根据当前的编译平台选择makefile去关联此平台
			dumpvar.mk
			在build开始之前展示出build的配置信息
			
			Define build types：
			BUILD_STATIC_LIBRARY
			BUILD_SHARED_LIBRARY
			BUILD_EXECUTABLE
			BUILD_PACKAGE
			BUILD_PREBUILT
			BUILD_MULTI_PREBUILT
			BUILD_JAVA_LIBRARY
			BUILD_STATIC_JAVA_LIBRARY
			BUILD_HOST_STATIC_LIBRARY
			BUILD_HOST_SHARED_LIBRARY
		
	2.product make files:
	device/qcom/<product_name>/
	vendor/qcom/proprietary/common/config

	overlay：用于覆盖对应APP中的配置，例如字符串

	device/qcom/common/vendorsetup.sh
	vendor/qcom/proprietary/common/config/device-vendor.mk
	build/target/product/
	build/target/board/

		Android.mk:
		PRODUCT_MAKEFILES :=$(LOCAL_DIR)/mobeeplus01a_xxx.mk
		mobeeplus01a_xxx.mk:
		包含一个关于产品 特殊/具体的？版本的定义，可能存在不止一个相同产品拥有多个版本信息
		PRODUCT_LOCALES 产品支持区，为lattices预设空间？en_GB语言包？;PRODUCT_PACKAGE 包含apk应用产品的各种不同版本，例如日历/联系人etc.;
		PRODUCT_COPY_FILES 去copy相应的文件去完成产品的编译 “the source path: path”
		BoardConfig.mk:
		用于去配置硬件板？，其定义了硬件部分的特性，例如母板与相关信息，bootloader，内核的链接
		vendorsetup.sh:
		通过 add_lunch_combo 来加入菜单选项在lunch函数里，这个参数是$(product_name)-$(compile type)，例如"add_lunch_combo msm8909_LMT-userdebug"
		
	3.modules:
	apk
	share/static library
	executable
	java library/package/apps/*
	framework/*

		package app  		app程序 .apk
		java library		java库 .jar
		shared library 		c/c++库 .so
		executable			二进制可执行文件
		static library 		c/c++静态库 .a
		static java library java静态库，编译到jar中
		prebuilt 			预编译库
		multi prebuilt		
		host executable 	本机执行文件
		host java library 	本机java库
		host shared library 本机共享库

2.template 
	package:
	LOCAL_PATH := $(call my-dir)
	include $(CLEAR_VARS)
	# Access to Java files in all subdirectories
	LOCAL_SRC_FILES := $(call all-subdir-java-files)
	# The current module dependent Java static library, if there are multiple
	separated by spaces
	LOCAL_STATIC_JAVA_LIBRARIES := static-library
	# Name of the current module
	LOCAL_PACKAGE_NAME := Email
	# Compile the APK file
	include $(BUILD_PACKAGE)

	executable：
	LOCAL_PATH:= $(call my-dir)
	# call function my-dir will return the path of Android.mk
	include $(CLEAR_VARS)
	# clean all variables mainly started with LOCAL_
	LOCAL_SRC_FILES:= foo.c # Source file list
	LOCAL_MODULE:= foo # The name of executable binary
	include $(BUILD_EXECUTABLE) # Start to build executable binary
	
	shared library：
	LOCAL_PATH:= $(call my-dir)
	# call function my-dir will return the path of Android.mk
	include $(CLEAR_VARS)
	# clean all variables mainly started with LOCAL_
	LOCAL_SRC_FILES:= foo.c bar.c # Source file list
	LOCAL_MODULE:= libfoo # The name of shared library
	LOCAL_PRELINK_MODULE := false # Prevent from prelink error
	include $(BUILD_SHARED_LIBRARY) # Start to build shared library
	
	static library：
	LOCAL_PATH:= $(call my-dir)
	# call function my-dir will return the path of Android.mk
	include $(CLEAR_VARS)
	# clean all variables mainly started with LOCAL_
	# Source file list
	LOCAL_SRC_FILES:= $(call all-subdir-c-files)
	# The name of static library
	LOCAL_MODULE:= libbar
	# Prevent from prelink error
	LOCAL_PRELINK_MODULE := false
	include $(BUILD_STATIC_LIBRARY) # Start to build static library

	prebuiltlibrary：
	include $(CLEAR_VARS)
	LOCAL_MODULE := foo-prebuilt
	LOCAL_SRC_FILES := libfoo.so
	LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include
	#definition here ensures that any module that depends on the prebuilt one will
	# have its # LOCAL_C_INCLUDES automatically prepended with the path
	# to the prebuilt library header directory
	include $(PREBUILT_SHARED_LIBRARY)
	
3.compile system编译系统
	$hmm：
	m,从tree的顶端make所有mk文件
	mm,从当前目录作为顶端开始make所有mk文件，不包括他们依赖的文件
	mmm,make指定目录mk文件，e.g: “mmm dir/：target1，target2”
	mma,和mm相比加上依赖文件的make
	mmma;和mma相比加上依赖文件的make
	
	$source build/envsetup.sh:
	including device/samsung/manta/vendorsetup.sh
	including device/qcom/common/vendorsetup.sh
	including device/generic/mini-emulator-x86_64/vendorsetup.sh
	including device/generic/mini-emulator-mips/vendorsetup.sh
	including device/generic/mini-emulator-armv7-a-neon/vendorsetup.sh
	including device/generic/mini-emulator-arm64/vendorsetup.sh
	including device/generic/mini-emulator-x86/vendorsetup.sh
	including device/htc/flounder/vendorsetup.sh
	including device/lge/mako/vendorsetup.sh
	including device/asus/tilapia/vendorsetup.sh
	including vendor/goldsand/vendorsetup.sh
	including vendor/qcom/proprietary/common/vendorsetup.sh
	including vendor/third-party/vendorsetup.sh
	including sdk/bash_completion/adb.bash
	
	$make help:
	通常的make目标：
	droid,默认的目标名
	clean,等同于rm -rf
	snod,从built-package里获取系统快照来快速rebuild
	offline-sdk-docs,生成html网页来展示开发者的SDK文档
	doc-comment-check-docs,不生成html网页来验证html文件文档链接的有效性
	libandroid_runtime,所有的JNI(java native interface，java本地接口)框架内容
	framework,所有的java框架内容
	services,系统服务(java)
	help,帮助文件
	
	apps_only：
	The target will compile the current configuration does not contain user, userdebug, eng tags (on the
	label, please refer to the "add new module") applications.
	
	droidcore：The goal is only the combination of several target dependent, it does not do more processing.
	
	dist_files：The object used to copy a file to the /out/dist directory.
	
	files：The goal is only the combination of several target dependent, it does not do more processing.
	
	prebuilt：The target depends on the $(ALL_PREBUILT), $(ALL_PREBUILT)'s role is to handle all the compiled
	files.
	
	$(modules_to_install)：
	Modules_to_install variable contains the module all will be installed under the current configuration
	(whether a module can be installed to depend on the product configuration file, the module tab and
	other information), the target will cause all will be installed modules compiled.
	
	$(modules_to_check)：The target is used to ensure that we define the building blocks are not redundant.
	
	$(INSTALLED_ANDROID_INFO_TXT_TARGET)：
	The target generates a current Build configuration of equipment information file, the file is generated
	path: out/target/product/<product_name>/android-info.txt
	
	systemimage：生成system.img.
	
	$(INSTALLED_BOOTIMAGE_TARGET):生成boot.img.
	
	$(INSTALLED_RECOVERYIMAGE_TARGET)：生成recovery.img.
	
	$(INSTALLED_USERDATAIMAGE_TARGET)：生成userdata.img.
	
	$(INSTALLED_CACHEIMAGE_TARGET)：生成cache.img.
	
	$(INSTALLED_FILES_FILE)：The target will 生成 out/target/product/<product_name> / installed-files.txt file, the file is already
	installed in the system image list file.
	
	make clean：表现为清除，等同于于清楚out目录下所有文件: rm -rf out/.
	
	make sdk：编译Android SDK.
	
	make clean-sdk：Compile product clean SDK.
	
	make update-api：更新api，在框架的api改变后我们应该首先去执行这个命令去更新，公共的api记录会放在 frameworks/base/api 这个文件夹里.
	
	make dist：build的执行，以及复制输出文件 MAKECMDGOALS 变量到 /out/dist 这个文件夹去.
	
	make all：编译所有的文件, whether defined for the current product will contain.
	
	make help：帮助信息,展示一些主要make目标.
	
	make snod：从已经编译好的包里恢复 --> 快速重新组建系统.
	
	make libandroid_runtime：编译所有的和JNI框架相关的内容.
	
	make framework：编译所有java框架的内容.
	
	make services：编译器系统服务和相关的一些内容.
	
	make <local_target>：一个特殊特定的模块编译信息，本地目标模块的名字.
	
	make clean-<local_target>：清除一个特定的模块.
	
	make dump-products：显示编译器的配置信息，所有部件例如：名字，特定支持的语言，即将会包括的模块信息.
	
	make PRODUCT-xxx-yyy：编译一个特殊/特别的产品
	
	make bootimage：生成boot.img(boot快照)
	
	make recoveryimage：生成recovery快照
	
	make userdataimage：生成userdata快照
	
	make cacheimage：生成cache快照