Android优美代码赏析0.0:Makefile

0.build-android

#!/bin/bash
if [ ! -e "./jdk1.6.0_23" ]; then
    tar xzf jdk1.6.0_23.tar.gz
fi

export PATH=$PWD/jdk1.6.0_23/bin:$PATH

. setenv

#make -j$CPU_JOB_NUM || exit 1

make || exit 0

 

1.主makefile
include build/core/main.mk

 

 

2.build/core/main.mk

 

subdir_makefiles := \
    $(shell build/tools/findleaves.py --prune=out --prune=.repo --prune=.git $(subdirs) Android.mk)



ifeq ($(SDK_ONLY),true)

# ----- SDK for Windows ------
# These configure the build targets that are available for the SDK under Windows.
# The first section defines all the C/C++ tools that can be compiled in C/C++,
# the second section defines all the Java ones (assuming javac is available.)

subdirs := \
    prebuilt \
    build/libs/host \
    build/tools/zipalign \
    dalvik/dexdump \
    dalvik/libdex \
    dalvik/tools/dmtracedump \
    dalvik/tools/hprof-conv \
    development/tools/line_endings \
    development/tools/etc1tool \
    sdk/emulator/mksdcard \
    sdk/sdklauncher \
    development/host \
    external/expat \
    external/libpng \
    external/qemu \
    external/sqlite/dist \
    external/zlib \
    frameworks/base \
    system/core/adb \
    system/core/fastboot \
    system/core/libcutils \
    system/core/liblog \
    system/core/libzipfile

# The following can only be built if "javac" is available.
# This check is used when building parts of the SDK under Cygwin.
ifneq (,$(shell which javac 2>/dev/null))
subdirs += \
    build/tools/signapk \
    dalvik/dx \
    libcore \
    sdk/archquery \
    sdk/androidprefs \
    sdk/apkbuilder \
    sdk/jarutils \
    sdk/layoutlib_api \
    sdk/layoutlib_utils \
    sdk/ninepatch \
    sdk/sdkstats \
    sdk/sdkmanager \
    sdk/layoutopt \
    development/apps \
    development/tools/mkstubs \
    packages
else
$(warning SDK_ONLY: javac not available.)
endif

# Exclude tools/acp when cross-compiling windows under linux
ifeq ($(findstring Linux,$(UNAME)),)
subdirs += build/tools/acp
endif

else    # !SDK_ONLY
ifeq ($(BUILD_TINY_ANDROID), true)

# TINY_ANDROID is a super-minimal build configuration, handy for board 
# bringup and very low level debugging

subdirs := \
    bionic \
    system/core \
    system/extras/ext4_utils \
    system/extras/su \
    build/libs \
    build/target \
    build/tools/acp \
    build/tools/apriori \
    build/tools/kcm \
    build/tools/soslim \
    external/elfcopy \
    external/elfutils \
    external/yaffs2 \
    external/zlib
else    # !BUILD_TINY_ANDROID

#
# Typical build; include any Android.mk files we can find.
#
subdirs := $(TOP)

FULL_BUILD := true

endif    # !BUILD_TINY_ANDROID

endif    # !SDK_ONLY
其中几个定义：

TOP := .
TOPDIR :=

BUILD_SYSTEM := $(TOPDIR)build/core

 

我们取 非SDK_ONLY来分析

 

3.build/tools/findleaves.py
中调用os.walk遍历工程目录
http://www.2cto.com/kf/201108/101784.html

 

 

4.include其他文件的顺序：

 

 

# Set up various standard variables based on configuration
# and host information.
include $(BUILD_SYSTEM)/config.mk

# This allows us to force a clean build - included after the config.make
# environment setup is done, but before we generate any dependencies.  This
# file does the rm -rf inline so the deps which are all done below will
# be generated correctly
include $(BUILD_SYSTEM)/cleanbuild.mk

VERSION_CHECK_SEQUENCE_NUMBER := 2
-include $(OUT_DIR)/versions_checked.mk
ifneq ($(VERSION_CHECK_SEQUENCE_NUMBER),$(VERSIONS_CHECKED))

$(info Checking build tools versions...)


# Bring in standard build system definitions.
include $(BUILD_SYSTEM)/definitions.mk

# Bring in dex_preopt.mk
include $(BUILD_SYSTEM)/dex_preopt.mk

# Can't use first-makefiles-under here because
# --mindepth=2 makes the prunes not work.
subdir_makefiles := \
    $(shell build/tools/findleaves.py --prune=out --prune=.repo --prune=.git $(subdirs) Android.mk)

include $(subdir_makefiles)

# -------------------------------------------------------------------
# Include any makefiles that must happen after the module makefiles
# have been included.
# TODO: have these files register themselves via a global var rather
# than hard-coding the list here.
ifdef FULL_BUILD
  # Only include this during a full build, otherwise we can't be
  # guaranteed that any policies were included.
  -include frameworks/policies/base/PolicyConfig.mk
endif

include $(BUILD_SYSTEM)/Makefile

 

 (待续)