Android Build System

Android build system is make based.

In this document Understanding the makefile Layers Building the Android Platform Building the Android Kernel Build Variants

makefile

Understanding the makefile

A makefile defines how to build a particular application. Makefiles typically include all of the following elements:

Name: Give your build a name (LOCAL_MODULE := <build_name>).
Local Variables: Clear local variables with CLEAR_VARS (include $(CLEAR_VARS)).
Files: Determine which files your application depends upon (LOCAL_SRC_FILES := main.c).
Tags: Define tags, as necessary (LOCAL_MODULE_TAGS := eng development).
Libraries: Define whether your application links with other libraries (LOCAL_SHARED_LIBRARIES := cutils).
Template file: Include a template file to define underlining make tools for a particular target (include $(BUILD_EXECUTABLE)).

《Android 内核剖析》第18章 Android 编译系统

Make based 目标：条件 .PHONY 声明目标
Android 源码文件结构

drwxr-xr-x    6 lucas  staff   306 Mar  4 12:37 .repo
-r--r--r--    1 lucas  staff    87 Oct  1 00:56 Makefile
drwxr-xr-x    3 lucas  staff   136 Oct 15 08:17 abi
drwxr-xr-x   10 lucas  staff   476 Oct 15 08:17 bionic
drwxr-xr-x    5 lucas  staff   170 Mar  1 13:23 bootable
drwxr-xr-x    7 lucas  staff   442 Mar  4 12:00 build
drwxr-xr-x   11 lucas  staff   612 Mar  4 12:00 cts
drwxr-xr-x   17 lucas  staff   782 Mar  4 12:00 dalvik
drwxr-xr-x   18 lucas  staff   714 Nov 25 17:30 development
drwxr-xr-x   11 lucas  staff   374 Mar  4 11:29 device
drwxr-xr-x    3 lucas  staff   136 Oct 15 08:17 docs
drwxr-xr-x  164 lucas  staff  5610 Mar  4 12:01 external
drwxr-xr-x   15 lucas  staff   510 Jan 25 14:49 frameworks
drwxr-xr-x   10 lucas  staff   442 Oct  1 01:01 gdk
drwxr-xr-x   12 lucas  staff   408 Nov 25 17:32 hardware
drwxr-xr-x   12 lucas  staff   680 Mar  4 12:01 libcore
drwxr-xr-x    4 lucas  staff   306 Jan 28 02:08 libnativehelper
drwxr-xr-x    8 lucas  staff   714 Jan 28 02:08 ndk
drwxr-xr-x    4 lucas  staff   238 Mar  7 21:57 out
drwxr-xr-x    8 lucas  staff   272 Nov 25 17:33 packages
drwxr-xr-x    5 lucas  staff   238 Nov 25 17:33 pdk
drwxr-xr-x   11 lucas  staff   374 Mar  4 12:00 prebuilts
drwxr-xr-x   53 lucas  staff  2006 Jan 28 02:09 sdk
drwxr-xr-x    9 lucas  staff   306 Oct  1 01:04 system
drwxr-xr-x    3 lucas  staff   102 Mar  4 12:00 tools

Make 系统

编译命令

三张方式：

编译整个Android系统

source ./build/envsetup.sh
make PRODUCT-ful-crespo-eng

编译子工程

make libbz
or mmm external bzip2

第19章 Android 系统编译