android linux 基础知识总结2

二   ubuntu下烧录内核和文件系统
1. 硬件： 
手机一台
usb转串口线一根
usb转网卡线一根

2. 软件环境
1> tftp 服务器
执行脚本： setup_tftpd.sh 安装和配置tftp服务器，我们默认以 /tftpboot 
为 tftp服务器的根目录，需要下载的文件都放在该目录下。

2> 获取待烧录的镜像文件
svn list svn://192.168.2.148/smartphone/td0901/release/images 查看服务器上的
版本情况，通常我们下载最新的,例如，下载9月18号发布的版本：
svn co svn://192.168.2.148/smartphone/td0901/release/images/images20090918

3> 烧录镜像文件
用以下文件为例，示范通过tftp烧写内核和文件系统
内核           zImage0917 
系统分区： system0918.img  
数据分区    data0918.img 
待烧写的以上文件必须存在于tftp服务器根目录/tftpboot下。
具体步骤：
首先连接好硬件设备进入blob下载模式
1> blob 起来后按任意键
Processing obm parameters...
Can't detect micco. Set PMIC as normal I2C mode.

NAND flash(Manu=0x98 Device=0xba) detected!
Slot 0 Found
get relocation table
Found Main Bad block table at address 0x0f000000, version 0x01
Found Mirror Bad block table at address 0x0efc0000, version 0x01

Consider yourself BLOBed!

blob version 2.0.5-pre3 for Marvell Littleton
Copyright (C) 1999 2000 2001 2002 2003 Jan-Derk Bakker and Erik Mouw
blob comes with ABSOLUTELY NO WARRANTY; read the GNU GPL for details.
This is free software, and you are welcome to redistribute it
under certain conditions; read the GNU GPL for details.
length not align with page size, change to 0x0
Read flash from 0x60000, length 0x0
Done
Autoboot (2 seconds) in progress, press any key to stop ..
Autoboot aborted
Type "help" to get a list of commands
blob> 

2> 通过 tftp 下载内核到pc内存 0x80800000 地址处 
blob> tftp zImage0917
Begin init ether usbnet!!!
***** Plug-in USB cable & config usbdnet now ****** 
exit check_usb_connection:1
TFTPing zImage0917*^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ OK.
received 6144 blocks (3145156 bytes)
tftp_cmd: file 'zImage0917' loaded via tftp to address 0x80800000.

3> 擦除原来的内核分区，0x100000 为分区起始地址，0x300000为分区长度
blob> nanderase -z 0x100000 0x400000
the current NAND chip does not support Block Unlocking.
Erase 0x300000 length data from flash: 0x100000
Erase flash from 0x100000, length 0x300000
........................Done

4> 烧写内存 0x80800000 开始 实际长度为 3145156 的内核数据到起始地址为 0x100000 的内核分区
blob> nandwrite -z 0x80800000 0x100000 3145156
the current NAND chip does not support Block Unlocking.
Write 0x2ffdc4 length data from RAM: 0x80800000 to flash: 0x100000
Write flash from 0x100000, length 0x2ffdc4
Erase flash from 0x100000, length 0x300000
........................Done
........................Done


5> 下载系统分区镜像文件到pc内存 0x80800000 地址处 
blob> tftp system0918.img
TFTPing system0918.img*^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ OK.
received 113138 blocks (57925824 bytes)
tftp_cmd: file 'system0918.img' loaded via tftp to address 0x80800000.

6> 擦除原来的flash系统分区
blob> nanderase -z 0x500000 0x4000000
the current NAND chip does not support Block Unlocking.
Erase 0x3e0f800 length data from flash: 0x400000
Erase flash from 0x400000, length 0x3e0f800
...................................................................................
...................................................................................
...................................................................................
..........................Done

7> 烧写数据到flash系统分区
blob> nandwrite -y 0x80800000 0x500000 57925824
the current NAND chip does not support Block Unlocking.
Write 0x373e0c0 length data from RAM: 0x80800000 to flash: 0x400000
Write flash from 0x400000, length 0x3591800
Erase flash from 0x400000, length 0x3591800
....................................................................................
.....................................................................................
................................................................................Done
....................................................................................
....................................................................................
................................................................Done

8> 下载数据分区镜像文件到pc内存 0x80800000 地址处 
blob> tftp data0918.img
TFTPing data0918.img*^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ OK.
received 33992 blocks (17402880 bytes)
tftp_cmd: file 'data0918.img' loaded via tftp to address 0x80800000.
blob> 

9> 擦除原来的flash数据分区
blob> nanderase -z 0x4500000 0xBB00000
the current NAND chip does not support Block Unlocking.
Erase 0xa81f000 length data from flash: 0x4400000
Erase flash from 0x4400000, length 0xa81f000
.....................................................................................
.....................................................................................
.....................................................................................
.....................................................................................
...................................................Done

10> 烧写数据镜像到flash数据分区
blob> nandwrite -y 0x80800000 0x4500000 17402880
the current NAND chip does not support Block Unlocking.
Write 0x1098c00 length data from RAM: 0x80800000 to flash: 0x4400000
Write flash from 0x4400000, length 0x1018000
Erase flash from 0x4400000, length 0x1018000
..................................................................................Done
..................................................................................Done
blob> 

flash分区图：
*******************************************
*        *          *         *           *
*  blob  *  kernel  *  system *    data   *
*        *          *         *           *
*******************************************
nanderase -z 0x100000 0x400000
tftp zImage
nandwrite -z 0x80800000 0x100000 <zImage-actual-length>
烧写system.img：
nanderase -z 0x500000 0x4000000
tftp system.img
nandwrite -y 0x80800000 0x500000 <system.img actual length>

烧写 userdata.img ：
nanderase -z 0x4500000 0xBB00000
tftp userdata.img
nandwrite -y 0x80800000 0x4500000 <userdata.img actual length>

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涉及的内容：
svn服务器的使用
android的编译系统，原理，工具链，辅助工具，参数等，环境变量，怎样单独添加编译一个单独的模块等。
android 的编译结果：文件系统分析
文件系统的使用，启动流程
设置模块流程分析
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1. Android编译系统分析
编译脚本及系统变量
build/envsetup.sh脚本分析
在编译源代码之前通常需要在android源代码顶层目录执行 . ./build/envsetup.sh 目的是为了使用
脚本 envsetup.sh 里面定义了一些函数：
function help()
function get_abs_build_var()
function get_build_var()
function check_product()
function check_variant()
function setpaths()
function printconfig()
function set_stuff_for_environment()
function set_sequence_number()
function settitle()
function choosetype()
function chooseproduct()
function choosevariant()
function tapas()
function choosecombo()
function print_lunch_menu()
function lunch()
function gettop
function m()
function findmakefile()
function mm()
function mmm()
function croot()
function pid()
function gdbclient()
function jgrep()
function cgrep()
function resgrep()
function getprebuilt
function tracedmdump()
function runhat()
function getbugreports()
function startviewserver()
function stopviewserver()
function isviewserverstarted()
function smoketest()
function runtest()
function runtest_py()
function godir ()

choosecombo 命令分析：
function choosecombo()
{
    choosesim $1
    echo
    echo
    choosetype $2

    echo
    echo
    chooseproduct $3

    echo
    echo
    choosevariant $4

    echo
    set_stuff_for_environment
    printconfig
}
会依次进行如下选择：
Build for the simulator or the device?
     1. Device
     2. Simulator
Which would you like? [1] 

Build type choices are:
     1. release
     2. debug
Which would you like? [1] 

Product choices are:
     1. emulator
     2. generic
     3. sim
     4. littleton
You can also type the name of a product if you know it.
Which would you like? [littleton] 

Variant choices are:
     1. user
     2. userdebug
     3. eng
Which would you like? [eng] user
默认选择以后会出现：
TARGET_PRODUCT=littleton
TARGET_BUILD_VARIANT=user
TARGET_SIMULATOR=false
TARGET_BUILD_TYPE=release
TARGET_ARCH=arm
HOST_ARCH=x86
HOST_OS=linux
HOST_BUILD_TYPE=release
BUILD_ID=
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function chooseproduct()函数分析：
choices=(`/bin/ls build/target/board/*/BoardConfig.mk vendor/*/*/BoardConfig.mk 2> /dev/null`)
读取 build/target/board/* 目录下的板配置文件：BoardConfig.mk
读取 vendor/*/*/目录下的板配置文件：BoardConfig.mk
choices 的值为：
build/target/board/emulator/BoardConfig.mk
build/target/board/generic/BoardConfig.mk
build/target/board/sim/BoardConfig.mk
vendor/marvell/littleton/BoardConfig.mk
经过：
    for choice in ${choices[@]}		
    do
        # The product name is the name of the directory containing
        # the makefile we found, above.
        prodlist=(${prodlist[@]} `dirname ${choice} | xargs basename`)
    done
的处理，prodlist的值为：
emulator generic sim littleton
所以选择菜单为：
Product choices are:
     1. emulator
     2. generic
     3. sim
     4. littleton
如果选择 4，那么 TARGET_PRODUCT 被赋值为： littleton。


board_config_mk := \
	$(strip $(wildcard \
		$(SRC_TARGET_DIR)/board/$(TARGET_DEVICE)/BoardConfig.mk \
		vendor/*/$(TARGET_DEVICE)/BoardConfig.mk \
	))



怎样添加一个模块
LOCAL_PATH:= $(call my-dir)
#编译静态库
include $(CLEAR_VARS)
LOCAL_MODULE = libhellos
LOCAL_CFLAGS = $(L_CFLAGS)
LOCAL_SRC_FILES = hellos.c
LOCAL_C_INCLUDES = $(INCLUDES)
LOCAL_SHARED_LIBRARIES := libcutils
LOCAL_COPY_HEADERS_TO := libhellos
LOCAL_COPY_HEADERS := hellos.h
include $(BUILD_STATIC_LIBRARY)

#编译动态库
include $(CLEAR_VARS)
LOCAL_MODULE = libhellod
LOCAL_CFLAGS = $(L_CFLAGS)
LOCAL_SRC_FILES = hellod.c
LOCAL_C_INCLUDES = $(INCLUDES)
LOCAL_SHARED_LIBRARIES := libcutils
LOCAL_COPY_HEADERS_TO := libhellod
LOCAL_COPY_HEADERS := hellod.h
include $(BUILD_SHARED_LIBRARY)

BUILD_TEST=true
ifeq ($(BUILD_TEST),true)
#使用静态库
include $(CLEAR_VARS)
LOCAL_MODULE := hellos
LOCAL_STATIC_LIBRARIES := libhellos
LOCAL_SHARED_LIBRARIES :=
LOCAL_LDLIBS += -ldl
LOCAL_CFLAGS := $(L_CFLAGS)
LOCAL_SRC_FILES := mains.c
LOCAL_C_INCLUDES := $(INCLUDES)
include $(BUILD_EXECUTABLE)

#使用动态库
include $(CLEAR_VARS)
LOCAL_MODULE := hellod
LOCAL_MODULE_TAGS := debug
LOCAL_SHARED_LIBRARIES := libc libcutils libhellod
LOCAL_LDLIBS += -ldl
LOCAL_CFLAGS := $(L_CFLAGS)
LOCAL_SRC_FILES := maind.c
LOCAL_C_INCLUDES := $(INCLUDES)
include $(BUILD_EXECUTABLE)
endif # ifeq ($(WPA_BUILD_SUPPLICANT),true)

########################
#local_target_dir := $(TARGET_OUT)/etc/wifi
#include $(CLEAR_VARS)
#LOCAL_MODULE := wpa_supplicant.conf
#LOCAL_MODULE_TAGS := user
#LOCAL_MODULE_CLASS := ETC
#LOCAL_MODULE_PATH := $(local_target_dir)
#LOCAL_SRC_FILES := $(LOCAL_MODULE)
#include $(BUILD_PREBUILT)
########################
系统变量解析
LOCAL_MODULE     － 编译的目标对象
LOCAL_SRC_FILES  － 编译的源文件
LOCAL_C_INCLUDES － 需要包含的头文件目录
LOCAL_SHARED_LIBRARIES － 链接时需要的外部库
LOCAL_PRELINK_MODULE   － 是否需要prelink处理
BUILD_SHARED_LIBRARY   － 指明要编译成动态库


LOCAL_PATH - 编译时的目录
$(call 目录，目录….) 目录引入操作符
如该目录下有个文件夹名称 src，则可以这样写 $(call src)，那么就会得到 src 目录的完整路径

include $(CLEAR_VARS) -清除之前的一些系统变量
CLEAR_VARS:= $(BUILD_SYSTEM)/clear_vars.mk
在 build/core/config.mk 定义 CLEAR_VARS:= $(BUILD_SYSTEM)/clear_vars.mk
通过include 包含自定义的.mk文件（即是自定义编译规则）或是引用系统其他的.mk文件（系统定义的编译规则）。

LOCAL_SRC_FILES － 编译的源文件
可以是.c, .cpp, .java, .S（汇编文件）或是.aidl等格式
不同的文件用空格隔开。如果编译目录子目录，采用相对路径，如子目录/文件名。也可以通过$(call 目录)，指明编译某目录
下所有.c/.cpp/.java/.S/ .aidl文件.追加文件 LOCAL_SRC_FILES += 文件

LOCAL_C_INCLUDES － 需要包含的头文件目录
可以是系统定义路径，也可以是相对路径. 如该编译目录下有个include目录，写法是include/*.h

LOCAL_SHARED_LIBRARIES  － 链接时需要的外部共享库
LOCAL_STATIC_LIBRARIES  － 链接时需要的外部外部静态
LOCAL_JAVA_LIBRARIES     加入jar包

LOCAL_MODULE － 编译的目标对象
module 是指系统的 native code，通常针对c,c++代码
./system/core/sh/Android.mk:32:LOCAL_MODULE:= sh
./system/core/libcutils/Android.mk:71:LOCAL_MODULE := libcutils
./system/core/cpio/Android.mk:9:LOCAL_MODULE := mkbootfs
./system/core/mkbootimg/Android.mk:8:LOCAL_MODULE := mkbootimg
./system/core/toolbox/Android.mk:61:LOCAL_MODULE:= toolbox
./system/core/logcat/Android.mk:10:LOCAL_MODULE:= logcat
./system/core/adb/Android.mk:65:LOCAL_MODULE := adb
./system/core/adb/Android.mk:125:LOCAL_MODULE := adbd
./system/core/init/Android.mk:20:LOCAL_MODULE:= init
./system/core/vold/Android.mk:24:LOCAL_MODULE:= vold
./system/core/mountd/Android.mk:13:LOCAL_MODULE:= mountd

LOCAL_PACKAGE_NAME 
Java 应用程序的名字用该变量定义
./packages/apps/Music/Android.mk:9:LOCAL_PACKAGE_NAME := Music
./packages/apps/Browser/Android.mk:14:LOCAL_PACKAGE_NAME := Browser
./packages/apps/Settings/Android.mk:8:LOCAL_PACKAGE_NAME := Settings
./packages/apps/Stk/Android.mk:10:LOCAL_PACKAGE_NAME := Stk
./packages/apps/Contacts/Android.mk:10:LOCAL_PACKAGE_NAME := Contacts
./packages/apps/Mms/Android.mk:8:LOCAL_PACKAGE_NAME := Mms
./packages/apps/Camera/Android.mk:8:LOCAL_PACKAGE_NAME := Camera
./packages/apps/Phone/Android.mk:11:LOCAL_PACKAGE_NAME := Phone
./packages/apps/VoiceDialer/Android.mk:8:LOCAL_PACKAGE_NAME := VoiceDialer


BUILD_SHARED_LIBRARY － 指明要编译成动态库。
编译的目标，用include 操作符
UILD_STATIC_LIBRARY来指明要编译成静态库。
如果是java文件的话，会用到系统的编译脚本host_java_library.mk，用BUILD_PACKAGE来指明。三个编译
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include $(BUILD_STATIC_LIBRARY)
BUILD_STATIC_LIBRARY:= $(BUILD_SYSTEM)/static_library.mk
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include $(BUILD_SHARED_LIBRARY)
./build/core/config.mk:50:BUILD_SHARED_LIBRARY:= $(BUILD_SYSTEM)/shared_library.mk
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include $(BUILD_HOST_SHARED_LIBRARY)
BUILD_HOST_SHARED_LIBRARY:= $(BUILD_SYSTEM)/host_shared_library.mk
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include $(BUILD_EXECUTABLE)
build/core/config.mk:51:BUILD_EXECUTABLE:= $(BUILD_SYSTEM)/executable.mk
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include $(BUILD_HOST_EXECUTABLE)
./build/core/config.mk:53:BUILD_HOST_EXECUTABLE:= $(BUILD_SYSTEM)/host_executable.mk
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BUILD_HOST_JAVA_LIBRARY:= $(BUILD_SYSTEM)/host_java_library.mk
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BUILD_JAVA_LIBRARY
./build/core/config.mk:58:BUILD_JAVA_LIBRARY:= $(BUILD_SYSTEM)/java_library.mk
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BUILD_STATIC_JAVA_LIBRARY 编译静态JAVA库
./build/core/config.mk:59:BUILD_STATIC_JAVA_LIBRARY:= $(BUILD_SYSTEM)/static_java_library.mk
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BUILD_HOST_JAVA_LIBRARY   编译本机用的JAVA库
./build/core/config.mk:60:BUILD_HOST_JAVA_LIBRARY:= $(BUILD_SYSTEM)/host_java_library.mk
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BUILD_HOST_STATIC_LIBRARY:= $(BUILD_SYSTEM)/host_static_library.mk
BUILD_HOST_SHARED_LIBRARY:= $(BUILD_SYSTEM)/host_shared_library.mk
BUILD_STATIC_LIBRARY:= $(BUILD_SYSTEM)/static_library.mk
BUILD_RAW_STATIC_LIBRARY := $(BUILD_SYSTEM)/raw_static_library.mk
BUILD_SHARED_LIBRARY:= $(BUILD_SYSTEM)/shared_library.mk
BUILD_EXECUTABLE:= $(BUILD_SYSTEM)/executable.mk
BUILD_RAW_EXECUTABLE:= $(BUILD_SYSTEM)/raw_executable.mk
BUILD_HOST_EXECUTABLE:= $(BUILD_SYSTEM)/host_executable.mk
BUILD_PACKAGE:= $(BUILD_SYSTEM)/package.mk
BUILD_HOST_PREBUILT:= $(BUILD_SYSTEM)/host_prebuilt.mk
BUILD_PREBUILT:= $(BUILD_SYSTEM)/prebuilt.mk
BUILD_MULTI_PREBUILT:= $(BUILD_SYSTEM)/multi_prebuilt.mk
BUILD_JAVA_LIBRARY:= $(BUILD_SYSTEM)/java_library.mk
BUILD_STATIC_JAVA_LIBRARY:= $(BUILD_SYSTEM)/static_java_library.mk
BUILD_HOST_JAVA_LIBRARY:= $(BUILD_SYSTEM)/host_java_library.mk
BUILD_DROIDDOC:= $(BUILD_SYSTEM)/droiddoc.mk
BUILD_COPY_HEADERS := $(BUILD_SYSTEM)/copy_headers.mk
BUILD_KEY_CHAR_MAP := $(BUILD_SYSTEM)/key_char_map.mk

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LOCAL_PRELINK_MODULE
	Prelink利用事先链接代替运行时链接的方法来加速共享库的加载，它不仅可以加快起动速度，还可以减少部分内存开销，
是各种Linux架构上用于减少程序加载时间、缩短系统启动时间和加快应用程序启动的很受欢迎的一个工具。程序运行时的
动态链接尤其是重定位(relocation)的开销对于大型系统来说是很大的。
	动态链接和加载的过程开销很大，并且在大多数的系统上, 函数库并不会常常被更动, 每次程序被执行时所进行的链接
动作都是完全相同的，对于嵌入式系统来说尤其如此。因此，这一过程可以改在运行时之前就可以预先处理好，即花一些时间
利用Prelink工具对动态共享库和可执行文件进行处理，修改这些二进制文件并加入相应的重定位等信息，节约了本来在程序
启动时的比较耗时的查询函数地址等工作，这样可以减少程序启动的时间，同时也减少了内存的耗用。 
	Prelink的这种做法当然也有代价：每次更新动态共享库时，相关的可执行文件都需要重新执行一遍Prelink才能保
证有效，因为新的共享库中的符号信息、地址等很可能与原来的已经不同了，这就是为什么 android framework代码一改动，
这时候就会导致相关的应用程序重新被编译。
这种代价对于嵌入式系统的开发者来说可能稍微带来一些复杂度，不过好在对用户来说几乎是可以忽略的。
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变量设置为false那么将不做prelink操作
LOCAL_PRELINK_MODULE := false
默认是需要prlink的，同时需要在 build/core/prelink-linux-arm.map 中加入
libhellod.so      0x96000000
这个map文件好像是制定动态库的地址的，在前面注释上面有一些地址范围的信息，注意库与库之间的间隔数，
如果指定不好的话编译的时候会提示说地址空间冲突的问题。另外，注意排序，这里要把数大的放到前面去，
按照大小降序排序。
解析 LOCAL_PRELINK_MODULE 变量
build/core/dynamic_binary.mk:94:ifeq ($(LOCAL_PRELINK_MODULE),true)
ifeq ($(LOCAL_PRELINK_MODULE),true)
$(prelink_output): $(prelink_input) $(TARGET_PRELINKER_MAP) $(APRIORI)
	$(transform-to-prelinked)
transform-to-prelinked定义：
./build/core/definitions.mk:1002:define transform-to-prelinked
define transform-to-prelinked
@mkdir -p $(dir $@)
@echo "target Prelink: $(PRIVATE_MODULE) ($@)"
$(hide) $(APRIORI) \
		--prelinkmap $(TARGET_PRELINKER_MAP) \
		--locals-only \
		--quiet \
		$< \
		--output $@
endef
./build/core/config.mk:183:APRIORI := $(HOST_OUT_EXECUTABLES)/apriori$(HOST_EXECUTABLE_SUFFIX)
prelink工具不是常用的prelink而是apriori，其源代码位于” <your_android>/build/tools/apriori”
参考文档：
动态库优化——Prelink（预连接）技术
http://www.eefocus.com/article/09-04/71629s.html


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LOCAL_ARM_MODE := arm
目前Android大部分都是基于Arm处理器的，Arm指令用两种模式Thumb(每条指令两个字节)和arm指令（每条指令四个字节）

LOCAL_CFLAGS += -O3 -fstrict-aliasing -fprefetch-loop-arrays
通过设定编译器操作，优化级别，-O0表示没有优化,-O1为缺省值，-O3优化级别最高
LOCAL_CFLAGS += -W -Wall
LOCAL_CFLAGS += -fPIC -DPIC
LOCAL_CFLAGS += -O2 -g -DADB_HOST=1  -Wall -Wno-unused-parameter
LOCAL_CFLAGS += -D_XOPEN_SOURCE -D_GNU_SOURCE -DSH_HISTORY
LOCAL_CFLAGS += -DUSEOVERLAY2
根据条件选择相应的编译参数
ifeq ($(TARGET_ARCH),arm)
LOCAL_CFLAGS += -DANDROID_GADGET=1
LOCAL_CFLAGS :=   $(PV_CFLAGS)
endif
ifeq ($(TARGET_BUILD_TYPE),release)
	LOCAL_CFLAGS += -O2
endif

LOCAL_LDLIBS := -lpthread
LOCAL_LDLIBS += -ldl

ifdef USE_MARVELL_MVED
LOCAL_WHOLE_STATIC_LIBRARIES += lib_il_mpeg4aspdecmved_wmmx2lnx lib_il_h264decmved_wmmx2lnx
LOCAL_SHARED_LIBRARIES += libMrvlMVED
else
LOCAL_WHOLE_STATIC_LIBRARIES += lib_il_h264dec_wmmx2lnx lib_il_mpeg4aspdec_wmmx2lnx
endif
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其他一些变量和脚本：
HOST_JNILIB_SUFFIX
LOCAL_MODULE_SUFFIX
LOCAL_MODULE_SUFFIX := $(HOST_JNILIB_SUFFIX)
HOST_GLOBAL_LDFLAGS
TARGET_GLOBAL_LDFLAGS
PRIVATE_LDFLAGS
LOCAL_LDLIBS
LOCAL_C_INCLUDES
LOCAL_STATIC_LIBRARIES
LOCAL_STATIC_LIBRARIES += codecJPDec_WMMX2LNX miscGen_WMMX2LNX
LOCAL_SHARED_LIBRARIES 
LOCAL_SHARED_LIBRARIES += libMrvlIPP
LOCAL_SHARED_LIBRARIES += $(common_SHARED_LIBRARIES)
LOCAL_SHARED_LIBRARIES += libMrvlIPP
LOCAL_SHARED_LIBRARIES += libdl
ifeq ($(TARGET_PRODUCT),littleton)
LOCAL_C_INCLUDES += vendor/marvell/littleton/m2d \
LOCAL_SHARED_LIBRARIES += libOmxCore
endif

vendor/marvell/littleton/littleton.mk:27:PRODUCT_NAME := littleton
vendor/marvell/littleton/littleton.mk:28:PRODUCT_DEVICE := littleton
vendor/marvell/littleton/AndroidProducts.mk:13:	$(LOCAL_DIR)/littleton.mk

vendor/sample/products/sample_addon.mk:40:PRODUCT_NAME := sample_addon
vendor/htc/dream-open/htc_dream.mk:6:PRODUCT_NAME := htc_dream
./vendor/htc/dream-open/htc_dream.mk:7:PRODUCT_DEVICE := dream-open
./vendor/htc/dream-open/AndroidProducts.mk:3:	$(LOCAL_DIR)/htc_dream.mk

build/target/product/generic.mk:26:PRODUCT_NAME := generic
build/target/product/generic_with_google.mk:20:PRODUCT_NAME := generic_with_google
build/target/product/min_dev.mk:6:PRODUCT_NAME := min_dev
build/target/product/core.mk:2:PRODUCT_NAME :=
build/target/product/sim.mk:7:PRODUCT_NAME := sim
build/target/product/sdk.mk:37:PRODUCT_NAME := sdk
build/tools/buildinfo.sh:20:echo "ro.product.name=$PRODUCT_NAME"

lunch sample_addon-eng
lunch htc_dream-eng
lunch generic-eng
lunch 1 
lunch sim-eng
TARGET_BUILD_TYPE=release
lunch 2
TARGET_BUILD_TYPE=debug
lunch  generic-user

.PHONY: systemtarball-nodeps
systemtarball-nodeps: $(FS_GET_STATS) \
                      $(filter-out systemtarball-nodeps stnod,$(MAKECMDGOALS))
	$(build-systemtarball-target)

.PHONY: stnod
stnod: systemtarball-nodeps
systemimage-nodeps snod

./core/main.mk:BUILD_SYSTEM := $(TOPDIR)build/core

./core/main.mk:include $(BUILD_SYSTEM)/config.mk
./core/main.mk:include $(BUILD_SYSTEM)/cleanbuild.mk
./core/main.mk:include $(BUILD_SYSTEM)/version_defaults.mk
./core/main.mk:include $(BUILD_SYSTEM)/definitions.mk
./core/main.mk:include $(BUILD_SYSTEM)/Makefile
./core/static_java_library.mk:include $(BUILD_SYSTEM)/java_library.mk
./core/host_java_library.mk:include $(BUILD_SYSTEM)/base_rules.mk
./core/executable.mk:include $(BUILD_SYSTEM)/dynamic_binary.mk
./core/java_library.mk:include $(BUILD_SYSTEM)/java.mk
./core/binary.mk:include $(BUILD_SYSTEM)/base_rules.mk
./core/raw_executable.mk:include $(BUILD_SYSTEM)/binary.mk
./core/prebuilt.mk:include $(BUILD_SYSTEM)/base_rules.mk
./core/host_executable.mk:include $(BUILD_SYSTEM)/binary.mk

./core/combo/select.mk:$(combo_target)PRELINKER_MAP := $(BUILD_SYSTEM)/prelink-$(combo_os_arch).map
./core/shared_library.mk:include $(BUILD_SYSTEM)/dynamic_binary.mk
./core/config.mk:include $(BUILD_SYSTEM)/pathmap.mk
./core/config.mk:BUILD_COMBOS:= $(BUILD_SYSTEM)/combo
./core/config.mk:CLEAR_VARS:= $(BUILD_SYSTEM)/clear_vars.mk
./core/config.mk:BUILD_HOST_STATIC_LIBRARY:= $(BUILD_SYSTEM)/host_static_library.mk
./core/config.mk:BUILD_HOST_SHARED_LIBRARY:= $(BUILD_SYSTEM)/host_shared_library.mk
./core/config.mk:BUILD_STATIC_LIBRARY:= $(BUILD_SYSTEM)/static_library.mk
./core/config.mk:BUILD_RAW_STATIC_LIBRARY := $(BUILD_SYSTEM)/raw_static_library.mk
./core/config.mk:BUILD_SHARED_LIBRARY:= $(BUILD_SYSTEM)/shared_library.mk
./core/config.mk:BUILD_EXECUTABLE:= $(BUILD_SYSTEM)/executable.mk
./core/config.mk:BUILD_RAW_EXECUTABLE:= $(BUILD_SYSTEM)/raw_executable.mk
./core/config.mk:BUILD_HOST_EXECUTABLE:= $(BUILD_SYSTEM)/host_executable.mk
./core/config.mk:BUILD_PACKAGE:= $(BUILD_SYSTEM)/package.mk
./core/config.mk:BUILD_HOST_PREBUILT:= $(BUILD_SYSTEM)/host_prebuilt.mk
./core/config.mk:BUILD_PREBUILT:= $(BUILD_SYSTEM)/prebuilt.mk
./core/config.mk:BUILD_MULTI_PREBUILT:= $(BUILD_SYSTEM)/multi_prebuilt.mk
./core/config.mk:BUILD_JAVA_LIBRARY:= $(BUILD_SYSTEM)/java_library.mk
./core/config.mk:BUILD_STATIC_JAVA_LIBRARY:= $(BUILD_SYSTEM)/static_java_library.mk
./core/config.mk:BUILD_HOST_JAVA_LIBRARY:= $(BUILD_SYSTEM)/host_java_library.mk
./core/config.mk:BUILD_DROIDDOC:= $(BUILD_SYSTEM)/droiddoc.mk
./core/config.mk:BUILD_COPY_HEADERS := $(BUILD_SYSTEM)/copy_headers.mk
./core/config.mk:BUILD_KEY_CHAR_MAP := $(BUILD_SYSTEM)/key_char_map.mk
./core/config.mk:HOST_JDK_TOOLS_JAR:= $(shell $(BUILD_SYSTEM)/find-jdk-tools-jar.sh)
./core/version_defaults.mk:INTERNAL_BUILD_ID_MAKEFILE := $(wildcard $(BUILD_SYSTEM)/build_id.mk)

./core/config.mk:include $(BUILD_SYSTEM)/envsetup.mk
./core/config.mk:include $(BUILD_SYSTEM)/combo/select.mk
./core/config.mk:include $(BUILD_SYSTEM)/combo/select.mk
./core/config.mk:include $(BUILD_SYSTEM)/combo/javac.mk
./core/product_config.mk:include $(BUILD_SYSTEM)/node_fns.mk
./core/product_config.mk:include $(BUILD_SYSTEM)/product.mk
./core/product_config.mk:include $(BUILD_SYSTEM)/device.mk
./core/dynamic_binary.mk:include $(BUILD_SYSTEM)/binary.mk
./core/host_static_library.mk:include $(BUILD_SYSTEM)/binary.mk
./core/java.mk:include $(BUILD_SYSTEM)/base_rules.mk
./core/host_shared_library.mk:include $(BUILD_SYSTEM)/binary.mk
./core/key_char_map.mk:include $(BUILD_SYSTEM)/base_rules.mk
./core/package.mk:include $(BUILD_SYSTEM)/java.mk
./core/static_library.mk:include $(BUILD_SYSTEM)/binary.mk
./core/definitions.mk:include $(BUILD_SYSTEM)/distdir.mk
./core/envsetup.mk:include $(BUILD_SYSTEM)/product_config.mk
./tools/apicheck/Android.mk:include $(BUILD_SYSTEM)/base_rules.mk
./tools/dexpreopt/Android.mk:include $(BUILD_SYSTEM)/host_prebuilt.mk

COMMON_GLOBAL_CFLAGS:= -DANDROID -fmessage-length=0 -W -Wall -Wno-unused
COMMON_DEBUG_CFLAGS:=
COMMON_RELEASE_CFLAGS:= -DNDEBUG -UDEBUG
COMMON_PACKAGE_SUFFIX := .zip
COMMON_JAVA_PACKAGE_SUFFIX := .jar
COMMON_ANDROID_PACKAGE_SUFFIX := .apk

ACP := $(HOST_OUT_EXECUTABLES)/acp$(HOST_EXECUTABLE_SUFFIX)
AIDL := $(HOST_OUT_EXECUTABLES)/aidl$(HOST_EXECUTABLE_SUFFIX)
MKBOOTFS := $(HOST_OUT_EXECUTABLES)/mkbootfs$(HOST_EXECUTABLE_SUFFIX)
MKBOOTIMG := $(HOST_OUT_EXECUTABLES)/mkbootimg$(HOST_EXECUTABLE_SUFFIX)
MKYAFFS2 := $(HOST_OUT_EXECUTABLES)/mkyaffs2image$(HOST_EXECUTABLE_SUFFIX)
APICHECK := $(HOST_OUT_EXECUTABLES)/apicheck$(HOST_EXECUTABLE_SUFFIX)
FS_GET_STATS := $(HOST_OUT_EXECUTABLES)/fs_get_stats$(HOST_EXECUTABLE_SUFFIX)
MKEXT2IMG := $(HOST_OUT_EXECUTABLES)/genext2fs$(HOST_EXECUTABLE_SUFFIX)
MKEXT2BOOTIMG := external/genext2fs/mkbootimg_ext2.sh
MKTARBALL := build/tools/mktarball.sh
DX := $(HOST_OUT_EXECUTABLES)/dx
LOCALIZE := $(HOST_OUT_EXECUTABLES)/localize$(HOST_EXECUTABLE_SUFFIX)
HOST_GLOBAL_LDFLAGS
TARGET_GLOBAL_LDFLAGS
PRIVATE_LDFLAGS

build/core/combo/linux-arm.mk:16:$(combo_target)NO_UNDEFINED_LDFLAGS := -Wl,--no-undefined
save_CFLAGS="$CFLAGS -g  -mabi=aapcs-linux"
LDFLAGS='$LDFLAGS  -lX11 -lxml2 -lXdmcp -lXau -lexpat -lXrender -lXft  -lfontconfig -lfreetype -lz'  
--without-libtiff "   # --with-gdktarget=directfb"
LDFLAGS=" -Wl,-rpath-link=$LD_LIBRARY_PATH  -L$PREFIX/lib  ${env_LDFLAGS} ${save_LDFLAGS}"
./vendor/marvell/external/alsa/alsa-lib/src/Mdroid.mk:43:LOCAL_CFLAGS += -mabi=aapcs-linux
./vendor/marvell/external/alsa/alsa-tools/Mdroid.mk:8:LOCAL_CFLAGS += -mabi=aapcs-linux
./vendor/marvell/littleton/libaudio/Mdroid.mk:22:LOCAL_CPPFLAGS += -mabi=aapcs-linux
./external/wpa_supplicant/Android.mk:35:L_CFLAGS += -mabi=aapcs-linux
./system/wlan/ti/sta_dk_4_0_4_32/CUDK/tiwlan_loader/Android.mk:88:LOCAL_CFLAGS = -Wall -Wstrict-prototypes 
$(CLI_DEBUGFLAGS) -D__LINUX__ $(DK_DEFINES) -mabi=aapcs-linux
./kernel/arch/arm/Makefile
ifeq ($(CONFIG_AEABI),y)
CFLAGS_ABI	:=-mabi=aapcs-linux -mno-thumb-interwork
else
CFLAGS_ABI	:=$(call cc-option,-mapcs-32,-mabi=apcs-gnu) $(call cc-option,-mno-thumb-interwork,)
endif
# Need -Uarm for gcc < 3.x
KBUILD_CFLAGS	+=$(CFLAGS_ABI) $(arch-y) $(tune-y) $(call cc-option,-mshort-load-bytes,$(call cc-option,
-malignment-traps,)) -msoft-float -Uarm
KBUILD_AFLAGS	+=$(CFLAGS_ABI) $(arch-y) $(tune-y) -msoft-float
CFLAGS="${temp_CFLAGS} -I/include -I/usr/include -I/usr/X11R7/include"
LDFLAGS="${temp_LDFLAGS} -L/lib -L/usr/lib -L/usr/X11R7/lib"



Android Build System
http://www.cublog.cn/u/8059/showart_1420446.html
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