Android编译过程详解（三）

109#---------------------------------------------------------------
110#Definemostoftheglobalvariables.Thesearetheonesthat
111#arespecifictotheuser'sbuildconfiguration.
112include$(BUILD_SYSTEM)/envsetup.mk
113
114#Boardsmaybedefinedunder$(SRC_TARGET_DIR)/board/$(TARGET_DEVICE)
115#orundervendor/*/$(TARGET_DEVICE).Searchinbothplaces,but
116#makesureonlyoneexists.
117#RealboardsshouldalwaysbeassociatedwithanOEMvendor.
118board_config_mk:=\
119$(strip$(wildcard\
120$(SRC_TARGET_DIR)/board/$(TARGET_DEVICE)/BoardConfig.mk\
121vendor/*/$(TARGET_DEVICE)/BoardConfig.mk\
122))
123ifeq($(board_config_mk),)
124$(errorNoconfigfilefoundforTARGET_DEVICE$(TARGET_DEVICE))
125endif
126ifneq($(words$(board_config_mk)),1)
127$(errorMultipleboardconfigfilesforTARGET_DEVICE$(TARGET_DEVICE):$(board_config_mk))
128endif
129include$(board_config_mk)
130TARGET_DEVICE_DIR:=$(patsubst%/,%,$(dir$(board_config_mk)))
131board_config_mk:=

上述代码在上一节已经见到过，只是分析了112行的envsetup.mk，根据上一节内容可知，envsetup.mk设置了很多OUT变量，最终在build/core/product_config.mk文件里，设置了TARGET_DEVICE=fs100。

141#Bringinstandardbuildsystemdefinitions.
142include$(BUILD_SYSTEM)/definitions.mk
...
347ifeq($(SDK_ONLY),true)
348
349#-----SDKforWindows------
350#TheseconfigurethebuildtargetsthatareavailablefortheSDKunderCygwin.
351#ThefirstsectiondefinesalltheC/C++toolsthatcanbecompiledunderCygwin,
352#thesecondsectiondefinesalltheJavaones(assumingjavacisavailable.)
353
354subdirs:=\
355prebuilt\
356build/libs/host\
357build/tools/zipalign\
...
382#Thefollowingcanonlybebuiltif"javac"isavailable.
383#ThischeckisusedwhenbuildingpartsoftheSDKunderCygwin.
384ifneq(,$(shellwhichjavac2>/dev/null))
385$(warningsdk-only:javacavailable.)
386subdirs+=\
387build/tools/signapk\
388dalvik/dx\
389dalvik/libcore\
...
414else#!SDK_ONLY
415ifeq($(BUILD_TINY_ANDROID),true)
416
417#TINY_ANDROIDisasuper-minimalbuildconfiguration,handyforboard
418#bringupandverylowleveldebugging
419
420subdirs:=\
421bionic\
422system/core\
423build/libs\
424build/target\
...
433else#!BUILD_TINY_ANDROID
434
435#
436#Typicalbuild;includeanyAndroid.mkfileswecanfind.
437#
438subdirs:=$(TOP)
439
440FULL_BUILD:=true
441
442endif#!BUILD_TINY_ANDROID
443
444endif#!SDK_ONLY
...
464#
465#Includeallofthemakefilesinthesystem
466#
467
468#Can'tusefirst-makefiles-underherebecause
469#--mindepth=2makestheprunesnotwork.
470subdir_makefiles:=\
471$(shellbuild/tools/findleaves.py--prune=out--prune=.repo--prune=.git$(subdirs)Android.mk)
472
473include$(subdir_makefiles)

26ifeq(,$(wildcard$(TARGET_DEVICE_DIR)/AndroidBoard.mk))
27ifeq(,$(wildcard$(TARGET_DEVICE_DIR)/Android.mk))
28$(errorMissing"$(TARGET_DEVICE_DIR)/AndroidBoard.mk")
29else
30#TODO:Removethischeckafterpeoplehavehadachancetoswitch,
31#afterApril2009.
32$(errorPleaserename"$(TARGET_DEVICE_DIR)/Android.mk"to"$(TARGET_DEVICE_DIR)/AndroidBoard.mk")
33endif
34endif
35include$(TARGET_DEVICE_DIR)/AndroidBoard.mk

由于将所有目录中Android.mk文件include进来，build/target/board/Android.mk自然被包含进来，根据前面分析，TARGET_DEVICE_DIR=vendor/*/fs100，其中26~35行用来判断对应的产品目录下是否存在AndrodiBoard.mk，如果不存在，提示出错退出，如果存在，将其包含到编译脚本中。

$cpbuild/target/board/generic/AndroidBoard.mkbuild/target/board/generic/BoardConfig.mkvendor/farsight/fs100/

至此，自定义Android编译选项基本步骤已经分部分析完，细节还需要针对不同开发板具体分析。

$mkdirvendor/farsight/
$touchvendor/farsight/vendorsetup.sh
$echo"add_lunch_combofs100-eng">vendor/farsight/vendorsetup.sh

2.仿着Android示例代码，在公司目录下创建products目录

$mkdir-pvendor/farsight/products

3.仿着Android示例代码，在products目录下创建两个mk文件

$touchvendor/farsight/products/AndroidProduct.mkvendor/farsight/products/fs100.mk

在AndroidProduct.mk里添加如下内容：

PRODUCT_MAKEFILES:=$(LOCAL_DIR)/fs100.mk

在产品配置文件里添加最基本信息

PRODUCT_PACKAGES:=\
IM\
VoiceDialer

$(callinherit-product,build/target/product/generic.mk)

#Overrides
PRODUCT_MANUFACTURER:=farsight
PRODUCT_NAME:=fs100
PRODUCT_DEVICE:=fs100

4.借鉴build/target/board/generic/AndroidBoard.mk和BoardConfig.mk，创建对应文件。

$cpbuild/target/board/generic/AndroidBoard.mkbuild/target/board/generic/BoardConfig.mkvendor/farsight/fs100/