Android编译过程详解(二)
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:
[html] 1 ### DO NOT EDIT THIS FILE ###
2 include build/core/main.mk
3 ### DO NOT EDIT THIS FILE ###
1 ### DO NOT EDIT THIS FILE ###
2 include build/core/main.mk
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
在main.mk里,定义了变量TOPDIR,TOP为当前目录,BUILD_SYSTEM为build/core目录。
在49行,包含了build/core/config.mk文件。
后面的代码是check环境 变量,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。这儿不是我们的重点,不再多说。
2. build/core/config.mk
该文件被main.mk包含。
定义了以下环境变量:
[plain] 16 SRC_HEADERS := \
17 $(TOPDIR)system/core/include \
18 $(TOPDIR)hardware/libhardware/include \
19 $(TOPDIR)hardware/libhardware_legacy/include \
20 $(TOPDIR)hardware/ril/include \
21 $(TOPDIR)dalvik/libnativehelper/include \
22 $(TOPDIR)frameworks/base/include \
23 $(TOPDIR)frameworks/base/opengl/include \
24 $(TOPDIR)external/skia/include
25 SRC_HOST_HEADERS:=$(TOPDIR)tools/include
26 SRC_LIBRARIES:= $(TOPDIR)libs
27 SRC_SERVERS:= $(TOPDIR)servers
28 SRC_TARGET_DIR := $(TOPDIR)build/target
29 SRC_API_DIR := $(TOPDIR)frameworks/base/api
16 SRC_HEADERS := \
17 $(TOPDIR)system/core/include \
18 $(TOPDIR)hardware/libhardware/include \
19 $(TOPDIR)hardware/libhardware_legacy/include \
20 $(TOPDIR)hardware/ril/include \
21 $(TOPDIR)dalvik/libnativehelper/include \
22 $(TOPDIR)frameworks/base/include \
23 $(TOPDIR)frameworks/base/opengl/include \
24 $(TOPDIR)external/skia/include
25 SRC_HOST_HEADERS:=$(TOPDIR)tools/include
26 SRC_LIBRARIES:= $(TOPDIR)libs
27 SRC_SERVERS:= $(TOPDIR)servers
28 SRC_TARGET_DIR := $(TOPDIR)build/target
29 SRC_API_DIR := $(TOPDIR)frameworks/base/api
[plain] .....然后定义了下面几个重要的编译命令
.....然后定义了下面几个重要的编译命令[plain] 43 CLEAR_VARS:= $(BUILD_SYSTEM)/clear_vars.mk
44 BUILD_HOST_STATIC_LIBRARY:= $(BUILD_SYSTEM)/host_static_library.mk
45 BUILD_HOST_SHARED_LIBRARY:= $(BUILD_SYSTEM)/host_shared_library.mk
46 BUILD_STATIC_LIBRARY:= $(BUILD_SYSTEM)/static_library.mk
47 BUILD_RAW_STATIC_LIBRARY := $(BUILD_SYSTEM)/raw_static_library.mk
48 BUILD_SHARED_LIBRARY:= $(BUILD_SYSTEM)/shared_library.mk
49 BUILD_EXECUTABLE:= $(BUILD_SYSTEM)/executable.mk
50 BUILD_RAW_EXECUTABLE:= $(BUILD_SYSTEM)/raw_executable.mk
51 BUILD_HOST_EXECUTABLE:= $(BUILD_SYSTEM)/host_executable.mk
52 BUILD_PACKAGE:= $(BUILD_SYSTEM)/package.mk
53 BUILD_HOST_PREBUILT:= $(BUILD_SYSTEM)/host_prebuilt.mk
54 BUILD_PREBUILT:= $(BUILD_SYSTEM)/prebuilt.mk
55 BUILD_MULTI_PREBUILT:= $(BUILD_SYSTEM)/multi_prebuilt.mk
56 BUILD_JAVA_LIBRARY:= $(BUILD_SYSTEM)/java_library.mk
57 BUILD_STATIC_JAVA_LIBRARY:= $(BUILD_SYSTEM)/static_java_library.mk
58 BUILD_HOST_JAVA_LIBRARY:= $(BUILD_SYSTEM)/host_java_library.mk
59 BUILD_DROIDDOC:= $(BUILD_SYSTEM)/droiddoc.mk
60 BUILD_COPY_HEADERS := $(BUILD_SYSTEM)/copy_headers.mk
61 BUILD_KEY_CHAR_MAP := $(BUILD_SYSTEM)/key_char_map.mk
43 CLEAR_VARS:= $(BUILD_SYSTEM)/clear_vars.mk
44 BUILD_HOST_STATIC_LIBRARY:= $(BUILD_SYSTEM)/host_static_library.mk
45 BUILD_HOST_SHARED_LIBRARY:= $(BUILD_SYSTEM)/host_shared_library.mk
46 BUILD_STATIC_LIBRARY:= $(BUILD_SYSTEM)/static_library.mk
47 BUILD_RAW_STATIC_LIBRARY := $(BUILD_SYSTEM)/raw_static_library.mk
48 BUILD_SHARED_LIBRARY:= $(BUILD_SYSTEM)/shared_library.mk
49 BUILD_EXECUTABLE:= $(BUILD_SYSTEM)/executable.mk
50 BUILD_RAW_EXECUTABLE:= $(BUILD_SYSTEM)/raw_executable.mk
51 BUILD_HOST_EXECUTABLE:= $(BUILD_SYSTEM)/host_executable.mk
52 BUILD_PACKAGE:= $(BUILD_SYSTEM)/package.mk
53 BUILD_HOST_PREBUILT:= $(BUILD_SYSTEM)/host_prebuilt.mk
54 BUILD_PREBUILT:= $(BUILD_SYSTEM)/prebuilt.mk
55 BUILD_MULTI_PREBUILT:= $(BUILD_SYSTEM)/multi_prebuilt.mk
56 BUILD_JAVA_LIBRARY:= $(BUILD_SYSTEM)/java_library.mk
57 BUILD_STATIC_JAVA_LIBRARY:= $(BUILD_SYSTEM)/static_java_library.mk
58 BUILD_HOST_JAVA_LIBRARY:= $(BUILD_SYSTEM)/host_java_library.mk
59 BUILD_DROIDDOC:= $(BUILD_SYSTEM)/droiddoc.mk
60 BUILD_COPY_HEADERS := $(BUILD_SYSTEM)/copy_headers.mk
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,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
[plain] 109 # ---------------------------------------------------------------
110 # Define most of the global variables. These are the ones that
111 # are specific to the user's build configuration.
112 include $(BUILD_SYSTEM)/envsetup.mk
113
114 # Boards may be defined under $(SRC_TARGET_DIR)/board/$(TARGET_DEVICE)
115 # or under vendor/*/$(TARGET_DEVICE). Search in both places, but
116 # make sure only one exists.
117 # Real boards should always be associated with an OEM vendor.
118 board_config_mk := \
119 $(strip $(wildcard \
120 $(SRC_TARGET_DIR)/board/$(TARGET_DEVICE)/BoardConfig.mk \
121 vendor/*/$(TARGET_DEVICE)/BoardConfig.mk \
122 ))
123 ifeq ($(board_config_mk),)
124 $(error No config file found for TARGET_DEVICE $(TARGET_DEVICE))
125 endif
126 ifneq ($(words $(board_config_mk)),1)
127 $(error Multiple board config files for TARGET_DEVICE $(TARGET_DEVICE): $(board_config_mk))
128 endif
129 include $(board_config_mk)
130 TARGET_DEVICE_DIR := $(patsubst %/,%,$(dir $(board_config_mk)))
131 board_config_mk :=
109 # ---------------------------------------------------------------
110 # Define most of the global variables. These are the ones that
111 # are specific to the user's build configuration.
112 include $(BUILD_SYSTEM)/envsetup.mk
113
114 # Boards may be defined under $(SRC_
补充:移动开发 , Android ,