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				22	<title>Android Build System</title>
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				72	<h1><a name="My_Project_" />Android Build System</h1>
				73
				74	<!-- Status is one of: Draft, Current, Needs Update, Obsolete -->
				75	<p style="text-align:center">
				76	<strong>Status:</strong> <em>Draft </em>
				77	<small>(as of May 18, 2006)</small>
				78	</p>
				79
				80	<p><b>Contents</b></p>
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				83	<div id="nav" class="nav-2-levels"></div>
				84
				85	<h2>Objective</h2>
				86	<p>The primary goals of reworking the build system are (1) to make dependencies
				87	work more reliably, so that when files need to rebuilt, they are, and (2) to
				88	improve performance of the build system so that unnecessary modules are not
				89	rebuilt, and so doing a top-level build when little or nothing needs to be done
				90	for a build takes as little time as possible.</p>
				91
				92	<h2>Principles and Use Cases and Policy</h2>
				93	<p>Given the above objective, these are the overall principles and use cases
				94	that we will support. This is not an exhaustive list.</p>
				95	<h3>Multiple Targets</h3>
				96	<p>It needs to be possible to build the Android platform for multiple targets.
				97	This means:</p>
				98	<ul>
				99	<li>The build system will support building tools for the host platform,
				100	both ones that are used in the build process itself, and developer tools
				101	like the simulator.</li>
				102	<li>The build system will need to be able to build tools on Linux
				103	(definitely Goobuntu and maybe Grhat), MacOS, and to some degree on
				104	Windows.</li>
				105	<li>The build system will need to be able to build the OS on Linux, and in
				106	the short-term, MacOS. Note that this is a conscious decision to stop
				107	building the OS on Windows. We are going to rely on the emulator there
				108	and not attempt to use the simulator. This is a requirement change now
				109	that the emulator story is looking brighter.</li>
				110	</ul>
				111	<h3>Non-Recursive Make</h3>
				112	<p>To achieve the objectives, the build system will be rewritten to use make
				113	non-recursively. For more background on this, read <a href="http://aegis.sourceforge.net/auug97.pdf">Recursive Make Considered Harmful</a>. For those that don't
				114	want PDF, here is the
				115	<a href="http://72.14.203.104/search?q=cache:HwuX7YF2uBIJ:aegis.sourceforge.net/auug97.pdf&hl=en&gl=us&ct=clnk&cd=2&client=firefox">Google translated version</a>.
				116	<h3>Rapid Compile-Test Cycles</h3>
				117	<p>When developing a component, for example a C++ shared library, it must be
				118	possible to easily rebuild just that component, and not have to wait more than a
				119	couple seconds for dependency checks, and not have to wait for unneeded
				120	components to be built.</p>
				121	<h3>Both Environment and Config File Based Settings</h3>
				122	<p>To set the target, and other options, some people on the team like to have a
				123	configuration file in a directory so they do not have an environment setup
				124	script to run, and others want an environment setup script to run so they can
				125	run builds in different terminals on the same tree, or switch back and forth
				126	in one terminal. We will support both.</p>
				127	<h3>Object File Directory / make clean</h3>
				128	<p>Object files and other intermediate files will be generated into a directory
				129	that is separate from the source tree. The goal is to have make clean be
				130	"rm -rf <obj>" in the tree root directory. The primary goals of
				131	this are to simplify searching the source tree, and to make "make clean" more
				132	reliable.</p>
				133
				134	<h3>SDK</h3>
				135	<p>The SDK will be a tarball that will allow non-OS-developers to write apps.
				136	The apps will actually be built by first building the SDK, and then building
				137	the apps against that SDK. This will hopefully (1) make writing apps easier
				138	for us, because we won't have to rebuild the OS as much, and we can use the
				139	standard java-app development tools, and (2) allow us to dog-food the SDK, to
				140	help ensure its quality. Cedric has suggested (and I agree) that apps built
				141	from the SDK should be built with ant. Stay tuned for more details as we
				142	figure out exactly how this will work.</p>
				143
				144	<h3>Dependecies</h3>
				145	<p>Dependencies should all be automatic. Unless there is a custom tool involved
				146	(e.g. the webkit has several), the dependencies for shared and static libraries,
				147	.c, .cpp, .h, .java, java libraries, etc., should all work without intervention
				148	in the Android.mk file.</p>
				149
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	150	<h3>Wildcard source files</h3>
				151	<p>Wildcarding source file will be discouraged. It may be useful in some
				152	scenarios. The default <code>$(wildcard *)</code> will not work due to the
				153	current directory being set to the root of the build tree.<p>
				154
				155	<h3>Multiple targets in one directory</h3>
				156	<p>It will be possible to generate more than one target from a given
				157	subdirectory. For example, libutils generates a shared library for the target
				158	and a static library for the host.</p>
				159
				160	<h3>Makefile fragments for modules</h3>
				161	<p><b>Android.mk</b> is the standard name for the makefile fragments that
				162	control the building of a given module. Only the top directory should
				163	have a file named "Makefile".</p>
				164
				165	<h3>Use shared libraries</h3>
				166	<p>Currently, the simulator is not built to use shared libraries. This should
				167	be fixed, and now is a good time to do it. This implies getting shared
				168	libraries to work on Mac OS.</p>
				169
				170
				171	<h2>Nice to Have</h2>
				172
				173	<p>These things would be nice to have, and this is a good place to record them,
				174	however these are not promises.</p>
				175
				176	<h3>Simultaneous Builds</h3>
				177	<p>The hope is to be able to do two builds for different combos in the same
				178	tree at the same time, but this is a stretch goal, not a requirement.
				179	Doing two builds in the same tree, not at the same time must work. (update:
				180	it's looking like we'll get the two builds at the same time working)</p>
				181
				182	<h3>Deleting headers (or other dependecies)</h3>
				183	<p>Problems can arise if you delete a header file that is referenced in
				184	".d" files. The easy way to deal with this is "make clean". There
				185	should be a better way to handle it. (from fadden)</p>
				186	<p>One way of solving this is introducing a dependency on the directory. The
				187	problem is that this can create extra dependecies and slow down the build.
				188	It's a tradeoff.</p>
				189
				190	<h3>Multiple builds</h3>
				191	<p>General way to perform builds across the set of known platforms. This
				192	would make it easy to perform multiple platform builds when testing a
				193	change, and allow a wide-scale "make clean". Right now the buildspec.mk
				194	or environment variables need to be updated before each build. (from fadden)</p>
				195
				196	<h3>Aftermarket Locales and Carrier</h3>
				197	<p>We will eventually need to add support for creating locales and carrier
				198	customizations to the SDK, but that will not be addressed right now.</p>
				199
				200
				201	<h2><a id="usage"/>Usage</h2>
				202	<p>You've read (or scrolled past) all of the motivations for this build system,
				203	and you want to know how to use it. This is the place.</p>
				204
				205	<h3>Your first build</h3>
				206	<p>The <a href="../building.html">Building</a> document describes how do do
				207	builds.</p>
				208
				209	<h3>build/envsetup.sh functions</h3>
				210	If you source the file build/envsetup.sh into your bash environment,
				211	<code>. build/envsetup.sh</code>you'll get a few helpful shell functions:
				212
				213	<ul>
				214	<li><b>printconfig</b> - Prints the current configuration as set by the
				215	lunch and choosecombo commands.</li>
				216	<li><b>m</b> - Runs <code>make</code> from the top of the tree. This is
				217	useful because you can run make from within subdirectories. If you have the
				218	<code>TOP</code> environment variable set, it uses that. If you don't, it looks
				219	up the tree from the current directory, trying to find the top of the tree.</li>
				220	<li><b>croot</b> - <code>cd</code> to the top of the tree.</li>
				221	<li><b>sgrep</b> - grep for the regex you provide in all .c, .cpp, .h, .java,
				222	and .xml files below the current directory.</li>
				223	</ul>
				224
				225	<h3>Build flavors/types</h3>
				226	<p>
				227	When building for a particular product, it's often useful to have minor
				228	variations on what is ultimately the final release build. These are the
				229	currently-defined "flavors" or "types" (we need to settle on a real name
				230	for these).
				231	</p>
				232
				233	<table border=1>
				234	<tr>
				235	<td>
				236	<code>eng<code>
				237	</td>
				238	<td>
				239	This is the default flavor. A plain "<code>make</code>" is the
				240	same as "<code>make eng</code>". <code>droid</code> is an alias
				241	for <code>eng</code>.
				242	<ul>
				243	<li>Installs modules tagged with: <code>eng</code>, <code>debug</code>,
				244	<code>user</code>, and/or <code>development</code>.
				245	<li>Installs non-APK modules that have no tags specified.
				246	<li>Installs APKs according to the product definition files, in
				247	addition to tagged APKs.
				248	<li><code>ro.secure=0</code>
				249	<li><code>ro.debuggable=1</code>
				250	<li><code>ro.kernel.android.checkjni=1</code>
				251	<li><code>adb</code> is enabled by default.
				252	</td>
				253	</tr>
				254	<tr>
				255	<td>
				256	<code>user<code>
				257	</td>
				258	<td>
				259	"<code>make user</code>"
				260	<p>
				261	This is the flavor intended to be the final release bits.
				262	<ul>
Elliott Hughes	32bfd70	2013-11-05 11:13:49 -0800	[diff] [blame]	263	<li>Installs modules tagged with <code>user</code>.
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	264	<li>Installs non-APK modules that have no tags specified.
				265	<li>Installs APKs according to the product definition files; tags
				266	are ignored for APK modules.
Daniel Micay	18a141c	2015-12-16 16:42:49 -0500	[diff] [blame]	267	<li><code>ro.adb.secure=1</code>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	268	<li><code>ro.secure=1</code>
				269	<li><code>ro.debuggable=0</code>
				270	<li><code>adb</code> is disabled by default.
				271	</td>
				272	</tr>
				273	<tr>
				274	<td>
				275	<code>userdebug<code>
				276	</td>
				277	<td>
				278	"<code>make userdebug</code>"
				279	<p>
				280	The same as <code>user</code>, except:
				281	<ul>
				282	<li>Also installs modules tagged with <code>debug</code>.
				283	<li><code>ro.debuggable=1</code>
				284	<li><code>adb</code> is enabled by default.
				285	</td>
				286	</tr>
				287	</table>
				288
				289	<p>
				290	If you build one flavor and then want to build another, you should run
				291	"<code>make installclean</code>" between the two makes to guarantee that
				292	you don't pick up files installed by the previous flavor. "<code>make
				293	clean</code>" will also suffice, but it takes a lot longer.
				294	</p>
				295
				296
				297	<h3>More pseudotargets</h3>
				298	<p>Sometimes you want to just build one thing. The following pseudotargets are
				299	there for your convenience:</p>
				300
				301	<ul>
				302	<li><b>droid</b> - <code>make droid</code> is the normal build. This target
				303	is here because the default target has to have a name.</li>
				304	<li><b>all</b> - <code>make all</code> builds everything <code>make
				305	droid</code> does, plus everything whose <code>LOCAL_MODULE_TAGS</code> do not
				306	include the "droid" tag. The build server runs this to make sure
				307	that everything that is in the tree and has an Android.mk builds.</li>
				308	<li><b>clean-$(LOCAL_MODULE)</b> and <b>clean-$(LOCAL_PACKAGE_NAME)</b> -
				309	Let you selectively clean one target. For example, you can type
				310	<code>make clean-libutils</code> and it will delete libutils.so and all of the
				311	intermediate files, or you can type <code>make clean-Home</code> and it will
				312	clean just the Home app.</li>
				313	<li><b>clean</b> - <code>make clean</code> deletes all of the output and
				314	intermediate files for this configuration. This is the same as <code>rm -rf
				315	out/<configuration>/</code></li>
				316	<li><b>clobber</b> - <code>make clobber</code> deletes all of the output
				317	and intermediate files for all configurations. This is the same as
				318	<code>rm -rf out/</code>.</li>
				319	<li><b>dataclean</b> - <code>make dataclean</code> deletes contents of the data
				320	directory inside the current combo directory. This is especially useful on the
				321	simulator and emulator, where the persistent data remains present between
				322	builds.</li>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	323	<li><b>LOCAL_MODULE</b> - Anything you specify as a <code>LOCAL_MODULE</code>
				324	in an Android.mk is made into a pseudotarget. For example, <code>make
				325	runtime</code> might be shorthand for <code>make
				326	out/linux-x86-debug/system/bin/runtime</code> (which would work), and
				327	<code>make libkjs</code> might be shorthand for <code>make
				328	out/linux-x86-debug/system/lib/libkjs.so</code> (which would also work).</li>
				329	<li><b>targets</b> - <code>make targets</code> will print a list of all of
				330	the LOCAL_MODULE names you can make.</li>
				331	</ul>
				332
				333	<h3><a name="templates"/>How to add another component to the build - Android.mk templates</h3>
				334	<p>You have a new library, a new app, or a new executable. For each of the
				335	common types of modules, there is a corresponding file in the templates
				336	directory. It will usually be enough to copy one of these, and fill in your
				337	own values. Some of the more esoteric values are not included in the
				338	templates, but are instead just documented here, as is the documentation
				339	on using custom tools to generate files.</p>
				340	<p>Mostly, you can just look for the TODO comments in the templates and do
				341	what it says. Please remember to delete the TODO comments when you're done
				342	to keep the files clean. The templates have minimal documentation in them,
				343	because they're going to be copied, and when that gets stale, the copies just
				344	won't get updated. So read on...</p>
				345
				346	<h4>Apps</h4>
				347	<p>Use the <code>templates/apps</code> file.</p>
				348	<p>This template is pretty self-explanitory. See the variables below for more
				349	details.</p>
				350
				351	<h4>Java Libraries</h4>
				352	<p>Use the <code>templates/java_library</code> file.</p>
				353	<p>The interesting thing here is the value of LOCAL_MODULE, which becomes
				354	the name of the jar file. (Actually right now, we're not making jar files yet,
				355	just directories of .class files, but the directory is named according to
				356	what you put in LOCAL_MODULE). This name will be what goes in the
				357	LOCAL_JAVA_LIBRARIES variable in modules that depend on your java library.</p>
				358
				359	<h4>C/C++ Executables</h4>
				360	<p>Use the <code>templates/executable</code> file, or the
				361	<code>templates/executable_host</code> file.</p>
				362	<p>This template has a couple extra options that you usually don't need.
				363	Please delete the ones you don't need, and remove the TODO comments. It makes
				364	the rest of them easier to read, and you can always refer back to the templates
				365	if you need them again later.</p>
				366	<p>By default, on the target these are built into /system/bin, and on the
				367	host, they're built into <combo>/host/bin. These can be overridden by setting
Colin Cross	639c336	2014-01-24 19:23:40 -0800	[diff] [blame]	368	<code>LOCAL_MODULE_PATH</code> or <code>LOCAL_MODULE_RELATIVE_PATH</code>. See
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	369	<a href="#moving-targets">Putting targets elsewhere</a>
				370	for more.</p>
				371
				372	<h4>Shared Libraries</h4>
				373	<p>Use the <code>templates/shared_library</code> file, or the
				374	<code>templates/shared_library_host</code> file.</p>
				375	<p>Remember that on the target, we use shared libraries, and on the host,
				376	we use static libraries, since executable size isn't as big an issue, and it
				377	simplifies distribution in the SDK.</p>
				378
				379	<h4>Static Libraries</h4>
				380	<p>Use the <code>templates/static_library</code> file, or the
				381	<code>templates/static_library_host</code> file.</p>
				382	<p>Remember that on the target, we use shared libraries, and on the host,
				383	we use static libraries, since executable size isn't as big an issue, and it
				384	simplifies distribution in the SDK.</p>
				385
				386	<h4><a name="custom-tools"/>Using Custom Tools</h4>
				387	<p>If you have a tool that generates source files for you, it's possible
				388	to have the build system get the dependencies correct for it. Here are
				389	a couple of examples. <code>$@</code> is the make built-in variable for
				390	"the current target." The <font color=red>red</font> parts are the parts you'll
				391	need to change.</p>
				392
				393	<p>You need to put this after you have declared <code>LOCAL_PATH</code> and
Colin Cross	d826264	2014-01-24 23:17:21 -0800	[diff] [blame]	394	<code>LOCAL_MODULE</code>, because the <code>$(local-generated-sources-dir)</code>
				395	and <code>$(local-host-generated-sources-dir)</code> macros use these variables
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	396	to determine where to put the files.
				397
				398	<h5>Example 1</h5>
				399	<p>Here, there is one generated file, called
				400	chartables.c, which doesn't depend on anything. And is built by the tool
				401	built to $(HOST_OUT_EXECUTABLES)/dftables. Note on the second to last line
				402	that a dependency is created on the tool.</p>
				403	<pre>
Colin Cross	d826264	2014-01-24 23:17:21 -0800	[diff] [blame]	404	intermediates:= $(local-generated-sources-dir)
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	405	GEN := $(intermediates)/<font color=red>chartables.c</font>
				406	$(GEN): PRIVATE_CUSTOM_TOOL = <font color=red>$(HOST_OUT_EXECUTABLES)/dftables $@</font>
				407	$(GEN): <font color=red>$(HOST_OUT_EXECUTABLES)/dftables</font>
				408	$(transform-generated-source)
				409	LOCAL_GENERATED_SOURCES += $(GEN)
				410	</pre>
				411
				412	<h5>Example 2</h5>
				413	<p>Here as a hypothetical example, we use use cat as if it were to transform
				414	a file. Pretend that it does something useful. Note how we use a
				415	target-specific variable called PRIVATE_INPUT_FILE to store the name of the
				416	input file.</p>
				417	<pre>
Colin Cross	d826264	2014-01-24 23:17:21 -0800	[diff] [blame]	418	intermediates:= $(local-generated-sources-dir)
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	419	GEN := $(intermediates)/<font color=red>file.c</font>
				420	$(GEN): PRIVATE_INPUT_FILE := $(LOCAL_PATH)/<font color=red>input.file</font>
				421	$(GEN): PRIVATE_CUSTOM_TOOL = <font color=red>cat $(PRIVATE_INPUT_FILE) > $@</font>
Dan Willemsen	bdd2e8e	2016-05-08 19:23:01 -0700	[diff] [blame]	422	$(GEN): <font color=red>$(LOCAL_PATH)/input.file</font>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	423	$(transform-generated-source)
				424	LOCAL_GENERATED_SOURCES += $(GEN)
				425	</pre>
				426
				427	<h5>Example 3</h5>
				428	<p>If you have several files that are all similar in
				429	name, and use the same tool, you can combine them. (here the *.lut.h files are
				430	the generated ones, and the *.cpp files are the input files)</p>
				431	<pre>
Colin Cross	d826264	2014-01-24 23:17:21 -0800	[diff] [blame]	432	intermediates:= $(local-generated-sources-dir)
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	433	GEN := $(addprefix $(intermediates)<font color=red>/kjs/, \
				434	array_object.lut.h \
				435	bool_object.lut.h \</font>
				436	)
				437	$(GEN): PRIVATE_CUSTOM_TOOL = <font color=red>perl libs/WebKitLib/WebKit/JavaScriptCore/kjs/create_hash_table $< -i > $@</font>
				438	$(GEN): $(intermediates)/<font color=red>%.lut.h</font> : $(LOCAL_PATH)/<font color=red>%.cpp</font>
				439	$(transform-generated-source)
				440	LOCAL_GENERATED_SOURCES += $(GEN)
				441	</pre>
				442
Jeongik Cha	1caa24f	2020-07-08 18:01:22 +0900	[diff] [blame]	443	<h3><a name="unbundled-build"/>Unbundled build</h3>
				444	<p>Unbundled build has several meanings by the context.
				445	Let me explain the meaning by the flags related to "unbundled build"</p>
				446	<h4>TARGET_BUILD_UNBUNDLED</h4>
Jiakai Zhang	11f44e2	2022-03-28 20:36:47 +0100	[diff] [blame]	447	<p>
				448	The source tree might not have the full platform sources. It turns on
				449	<code>TARGET_BUILD_USE_PREBUILT_SDKS</code>, unless
				450	<code>UNBUNDLED_BUILD_SDKS_FROM_SOURCE</code> is set. It is always set if
				451	<code>TARGET_BUILD_APPS</code> or <code>TARGET_BUILD_UNBUNDLED_IMAGE</code> is set.
				452	</p>
Jeongik Cha	1caa24f	2020-07-08 18:01:22 +0900	[diff] [blame]	453	<h4>TARGET_BUILD_USE_PREBUILT_SDKS</h4>
				454	<p>It is an internal flag. If it is set, prebuilt SDKs are used, even if a module's
				455	<code>LOCAL_SDK_VERSION</code> is <code>current</code> (including <code>system_current</code>,
				456	<code>core_current</code>, and so on). If it is unset, build current SDKs,
				457	and use them as usual.</p>
				458	<h4>DISABLE_PREOPT</h4>
				459	<p>It is an internal flag as well. If it is set, dexpreopt is disabled.
				460	It is always set if <code>TARGET_BUILD_APPS</code> or <code>TARGET_BUILD_UNBUNDLED_IMAGE</code> is set,
				461	because dexpreopt tightly depends on the platform.</p>
				462	<h4>TARGET_BUILD_APPS</h4>
				463	<p>Build the apps that can be distributed outside the platform, so it turns on
				464	<code>TARGET_BUILD_UNBUNDLED</code> and <code>DISABLE_PREOPT</code>.
				465	Also, it turns on <code>TARGET_BUILD_USE_PREBUILT_SDKS</code>, unless
				466	<code>UNBUNDLED_BUILD_SDKS_FROM_SOURCE</code> is set.</p>
				467	<h4>TARGET_BUILD_UNBUNDLED_IMAGE</h4>
				468	<p>It is similar to <code>TARGET_BUILD_APPS</code>, but its target is an unbundled partition
				469	(such as the vendor partition). Accordingly, it sets <code>TARGET_BUILD_UNBUNDLED</code> and <code>DISABLE_PREOPT</code>.
				470	We can call the partition unbundled, because the partition can be distributed outside the platform.
				471	And also, it turns on <code>TARGET_BUILD_USE_PREBUILT_SDKS</code>, unless
				472	<code>UNBUNDLED_BUILD_SDKS_FROM_SOURCE</code> is set.</p>
				473
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	474	<h3><a name="platform-specific"/>Platform specific conditionals</h3>
				475	<p>Sometimes you need to set flags specifically for different platforms. Here
				476	is a list of which values the different build-system defined variables will be
				477	set to and some examples.</p>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	478	<table cellspacing=25>
				479	<tr>
				480	<td valign=top align=center>
				481	<b>HOST_OS</b><br/>
				482	linux<br/>
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	483	darwin
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	484	</td>
				485	<td valign=top align=center>
				486	<b>HOST_ARCH</b><br/>
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	487	x86<br/>
				488	x86_64
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	489	</td>
				490	<td valign=top align=center>
				491	<b>HOST_BUILD_TYPE</b><br/>
				492	release<br/>
				493	debug
				494	</td>
				495	</tr>
				496	<tr>
				497	<td valign=top align=center>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	498	<b>TARGET_ARCH</b><br/>
				499	arm<br/>
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	500	arm64<br/>
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	501	x86<br/>
				502	x86_64
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	503	</td>
				504	<td valign=top align=center>
				505	<b>TARGET_BUILD_TYPE</b><br/>
				506	release<br/>
				507	debug
				508	</td>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	509	</tr>
				510	</table>
				511
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	512	<p>There are also special variables to use instead of conditionals. Many of the
				513	normal variables (LOCAL_SRC_FILES, LOCAL_CFLAGS, etc) can be conditionally added
				514	to with _{arch} _{32\|64}, and for the host, _{os}.</p>
				515
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	516	<h4>Some Examples</h4>
Jeff Brown	e33ba4c	2011-07-11 22:11:46 -0700	[diff] [blame]	517	<pre>ifeq ($(TARGET_BUILD_TYPE),release)
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	518	LOCAL_CFLAGS += -DNDEBUG=1
				519	endif
				520
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	521	LOCAL_CFLAGS_arm += -DTARGET_IS_ARM
				522
				523	LOCAL_CFLAGS_64 += -DBIG_POINTER
				524
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	525	# from libutils
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	526	# Use the futex based mutex and condition variable
				527	# implementation from android-arm because it's shared mem safe
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	528	LOCAL_SRC_FILES_linux += futex_synchro.c
				529	LOCAL_LDLIBS_linux += -lrt -ldl
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	530
				531	</pre>
				532
				533
				534	<h3><a name="moving-modules"/>Putting modules elsewhere</h3>
				535	<p>If you have modules that normally go somewhere, and you need to have them
Colin Cross	639c336	2014-01-24 19:23:40 -0800	[diff] [blame]	536	build somewhere else, read this.</p>
				537	<p>If you have modules that need to go in a subdirectory of their normal
				538	location, for example HAL modules that need to go in /system/lib/hw or
				539	/vendor/lib/hw, set LOCAL_MODULE_RELATIVE_PATH in your Android.mk, for
				540	example:</p>
				541	<pre>
				542	LOCAL_MODULE_RELATIVE_PATH := hw
				543	</pre>
				544	<p>If you have modules that need to go in an entirely different location, for
				545	example the root filesystem instead of in /system, add these lines to your
				546	Android.mk:</p>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	547	<pre>
Tom Cherry	6b28af3	2019-04-16 15:18:52 -0700	[diff] [blame]	548	LOCAL_MODULE_PATH := $(TARGET_ROOT_OUT)
				549	LOCAL_UNSTRIPPED_PATH := $(TARGET_ROOT_OUT_UNSTRIPPED)
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	550	</pre>
Colin Cross	639c336	2014-01-24 19:23:40 -0800	[diff] [blame]	551	<p>For executables and libraries, you need to specify a
				552	<code>LOCAL_UNSTRIPPED_PATH</code> location if you specified a
				553	<code>LOCAL_MODULE_PATH</code>, because on target builds, we keep
				554	the unstripped executables so GDB can find the symbols.
				555	<code>LOCAL_UNSTRIPPED_PATH</code> is not necessary if you only specified
				556	<code>LOCAL_MODULE_RELATIVE_PATH</code>.</p>
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	557	<p>Look in <code>core/envsetup.mk</code> for all of the variables defining
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	558	places to build things.</p>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	559
				560
				561	<h3>Android.mk variables</h3>
				562	<p>These are the variables that you'll commonly see in Android.mk files, listed
				563	alphabetically.</p>
				564	<p>But first, a note on variable naming:
				565	<ul>
				566	<li><b>LOCAL_</b> - These variables are set per-module. They are cleared
				567	by the <code>include $(CLEAR_VARS)</code> line, so you can rely on them
				568	being empty after including that file. Most of the variables you'll use
				569	in most modules are LOCAL_ variables.</li>
				570	<li><b>PRIVATE_</b> - These variables are make-target-specific variables. That
				571	means they're only usable within the commands for that module. It also
				572	means that they're unlikely to change behind your back from modules that
				573	are included after yours. This
				574	<a href="http://www.gnu.org/software/make/manual/make.html#Target_002dspecific">link to the make documentation</a>
				575	describes more about target-specific variables. Please note that there
				576	are a couple of these laying around the tree that aren't prefixed with
				577	PRIVATE_. It is safe, and they will be fixed as they are discovered.
				578	Sorry for the confusion.</li>
				579	<li><b>INTERNAL_</b> - These variables are critical to functioning of
				580	the build system, so you shouldn't create variables named like this, and
				581	you probably shouldn't be messing with these variables in your makefiles.
				582	</li>
				583	<li><b>HOST_</b> and <b>TARGET_</b> - These contain the directories
				584	and definitions that are specific to either the host or the target builds.
				585	Do not set variables that start with HOST_ or TARGET_ in your makefiles.
				586	</li>
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	587	<li><b>HOST_CROSS_</b> - These contain the directories and definitions that
				588	are specific to cross-building host binaries. The common case is building
				589	windows host tools on linux. Do not set variables that start with
				590	HOST_CROSS_ in your makefiles.
				591	</li>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	592	<li><b>BUILD_</b> and <b>CLEAR_VARS</b> - These contain the names of
				593	well-defined template makefiles to include. Some examples are CLEAR_VARS
				594	and BUILD_HOST_PACKAGE.</li>
				595	<li>Any other name is fair-game for you to use in your Android.mk. However,
				596	remember that this is a non-recursive build system, so it is possible that
				597	your variable will be changed by another Android.mk included later, and be
				598	different when the commands for your rule / module are executed.</li>
				599	</ul>
				600	</p>
				601
Colin Cross	e8ee68b	2017-04-07 16:28:41 -0700	[diff] [blame]	602	<h4>LOCAL_ANNOTATION_PROCESSORS</h4>
				603	<p>Set this to a list of modules built with <code>BUILD_HOST_JAVA_LIBRARY</code>
				604	to have their jars passed to javac with -processorpath for use as annotation
				605	processors.</p>
				606
				607	<h4>LOCAL_ANNOTATION_PROCESSOR_CLASSES</h4>
				608	<p>Set this to a list of classes to be passed to javac as -processor arguments.
				609	This list is would be unnecessary, as javac will autodetect annotation processor
				610	classes, except that the Grok tool that is used on the Android source code
				611	does not autodetect them and requires listing them manually.</p>
				612
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	613	<h4>LOCAL_ASSET_FILES</h4>
				614	<p>In Android.mk files that <code>include $(BUILD_PACKAGE)</code> set this
				615	to the set of files you want built into your app. Usually:</p>
				616	<p><code>LOCAL_ASSET_FILES += $(call find-subdir-assets)</code></p>
				617	<p>This will probably change when we switch to ant for the apps' build
				618	system.</p>
				619
				620	<h4>LOCAL_CC</h4>
				621	<p>If you want to use a different C compiler for this module, set LOCAL_CC
				622	to the path to the compiler. If LOCAL_CC is blank, the appropriate default
				623	compiler is used.</p>
				624
				625	<h4>LOCAL_CXX</h4>
				626	<p>If you want to use a different C++ compiler for this module, set LOCAL_CXX
				627	to the path to the compiler. If LOCAL_CXX is blank, the appropriate default
				628	compiler is used.</p>
				629
				630	<h4>LOCAL_CFLAGS</h4>
				631	<p>If you have additional flags to pass into the C or C++ compiler, add
				632	them here. For example:</p>
				633	<p><code>LOCAL_CFLAGS += -DLIBUTILS_NATIVE=1</code></p>
				634
				635	<h4>LOCAL_CPPFLAGS</h4>
				636	<p>If you have additional flags to pass into <i>only</i> the C++ compiler, add
				637	them here. For example:</p>
				638	<p><code>LOCAL_CPPFLAGS += -ffriend-injection</code></p>
				639	<code>LOCAL_CPPFLAGS</code> is guaranteed to be after <code>LOCAL_CFLAGS</code>
				640	on the compile line, so you can use it to override flags listed in
				641	<code>LOCAL_CFLAGS</code>.
				642
				643	<h4>LOCAL_CPP_EXTENSION</h4>
				644	<p>If your C++ files end in something other than "<code>.cpp</code>",
				645	you can specify the custom extension here. For example:</p>
				646	<p><code>LOCAL_CPP_EXTENSION := .cc</code></p>
				647	Note that all C++ files for a given module must have the same
				648	extension; it is not currently possible to mix different extensions.
				649
				650	<h4>LOCAL_NO_DEFAULT_COMPILER_FLAGS</h4>
				651	<p>Normally, the compile line for C and C++ files includes global include
				652	paths and global cflags. If <code>LOCAL_NO_DEFAULT_COMPILER_FLAGS</code>
				653	is non-empty, none of the default includes or flags will be used when compiling
				654	C and C++ files in this module.
				655	<code>LOCAL_C_INCLUDES</code>, <code>LOCAL_CFLAGS</code>, and
				656	<code>LOCAL_CPPFLAGS</code> will still be used in this case, as will
				657	any <code>DEBUG_CFLAGS</code> that are defined for the module.
				658
				659	<h4>LOCAL_COPY_HEADERS</h4>
				660	<p class=warning>This will be going away.</p>
				661	<p>The set of files to copy to the install include tree. You must also
				662	supply <code>LOCAL_COPY_HEADERS_TO</code>.</p>
				663	<p>This is going away because copying headers messes up the error messages, and
				664	may lead to people editing those headers instead of the correct ones. It also
				665	makes it easier to do bad layering in the system, which we want to avoid. We
				666	also aren't doing a C/C++ SDK, so there is no ultimate requirement to copy any
				667	headers.</p>
				668
				669	<h4>LOCAL_COPY_HEADERS_TO</h4>
				670	<p class=warning>This will be going away.</p>
				671	<p>The directory within "include" to copy the headers listed in
				672	<code>LOCAL_COPY_HEADERS</code> to.</p>
				673	<p>This is going away because copying headers messes up the error messages, and
				674	may lead to people editing those headers instead of the correct ones. It also
				675	makes it easier to do bad layering in the system, which we want to avoid. We
				676	also aren't doing a C/C++ SDK, so there is no ultimate requirement to copy any
				677	headers.</p>
				678
				679	<h4>LOCAL_C_INCLUDES</h4>
				680	<p>Additional directories to instruct the C/C++ compilers to look for header
				681	files in. These paths are rooted at the top of the tree. Use
				682	<code>LOCAL_PATH</code> if you have subdirectories of your own that you
				683	want in the include paths. For example:</p>
				684	<p><code>
				685	LOCAL_C_INCLUDES += extlibs/zlib-1.2.3<br/>
				686	LOCAL_C_INCLUDES += $(LOCAL_PATH)/src
				687	</code></p>
				688	<p>You should not add subdirectories of include to
				689	<code>LOCAL_C_INCLUDES</code>, instead you should reference those files
				690	in the <code>#include</code> statement with their subdirectories. For
				691	example:</p>
				692	<p><code>#include <utils/KeyedVector.h></code><br/>
				693	not <code><s>#include <KeyedVector.h></s></code></p>
				694	<p>There are some components that are doing this wrong, and should be cleaned
				695	up.</p>
				696
				697	<h4>LOCAL_MODULE_TAGS</h4>
				698	<p>Set <code>LOCAL_MODULE_TAGS</code> to any number of whitespace-separated
				699	tags. If the tag list is empty or contains <code>droid</code>, the module
Elliott Hughes	32bfd70	2013-11-05 11:13:49 -0800	[diff] [blame]	700	will get installed as part of a <code>make droid</code>. Otherwise, it will
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	701	only get installed by running <code>make <your-module></code>
				702	or with the <code>make all</code> pseudotarget.</p>
				703
				704	<h4>LOCAL_REQUIRED_MODULES</h4>
				705	<p>Set <code>LOCAL_REQUIRED_MODULES</code> to any number of whitespace-separated
				706	module names, like "libblah" or "Email". If this module is installed, all
				707	of the modules that it requires will be installed as well. This can be
				708	used to, e.g., ensure that necessary shared libraries or providers are
				709	installed when a given app is installed.
				710
				711	<h4>LOCAL_FORCE_STATIC_EXECUTABLE</h4>
				712	<p>If your executable should be linked statically, set
				713	<code>LOCAL_FORCE_STATIC_EXECUTABLE:=true</code>. There is a very short
Tom Cherry	6b28af3	2019-04-16 15:18:52 -0700	[diff] [blame]	714	list of libraries that we have in static form (currently only libc).</p>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	715
				716	<h4>LOCAL_GENERATED_SOURCES</h4>
				717	<p>Files that you add to <code>LOCAL_GENERATED_SOURCES</code> will be
				718	automatically generated and then linked in when your module is built.
				719	See the <a href="#custom-tools">Custom Tools</a> template makefile for an
				720	example.</p>
				721
Brian Carlstrom	f184a0f	2010-02-01 11:13:32 -0800	[diff] [blame]	722	<h4>LOCAL_JAVACFLAGS</h4>
				723	<p>If you have additional flags to pass into the javac compiler, add
				724	them here. For example:</p>
				725	<p><code>LOCAL_JAVACFLAGS += -Xlint:deprecation</code></p>
				726
Paul Duffin	3ca9298	2016-09-20 15:12:30 +0100	[diff] [blame]	727	<h4>LOCAL_ERROR_PRONE_FLAGS</h4>
				728	<p>If you have additional flags to pass into the error prone compiler, add
				729	them here. For example:</p>
				730	<p><code>LOCAL_ERROR_PRONE_FLAGS += -Xep:ClassCanBeStatic:ERROR</code></p>
				731
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	732	<h4>LOCAL_JAVA_LIBRARIES</h4>
				733	<p>When linking Java apps and libraries, <code>LOCAL_JAVA_LIBRARIES</code>
				734	specifies which sets of java classes to include. Currently there are
				735	two of these: <code>core</code> and <code>framework</code>.
				736	In most cases, it will look like this:</p>
				737	<p><code>LOCAL_JAVA_LIBRARIES := core framework</code></p>
				738	<p>Note that setting <code>LOCAL_JAVA_LIBRARIES</code> is not necessary
				739	(and is not allowed) when building an APK with
				740	"<code>include $(BUILD_PACKAGE)</code>". The appropriate libraries
				741	will be included automatically.</p>
				742
				743	<h4>LOCAL_LDFLAGS</h4>
				744	<p>You can pass additional flags to the linker by setting
				745	<code>LOCAL_LDFLAGS</code>. Keep in mind that the order of parameters is
				746	very important to ld, so test whatever you do on all platforms.</p>
				747
				748	<h4>LOCAL_LDLIBS</h4>
				749	<p><code>LOCAL_LDLIBS</code> allows you to specify additional libraries
				750	that are not part of the build for your executable or library. Specify
				751	the libraries you want in -lxxx format; they're passed directly to the
				752	link line. However, keep in mind that there will be no dependency generated
				753	for these libraries. It's most useful in simulator builds where you want
				754	to use a library preinstalled on the host. The linker (ld) is a particularly
				755	fussy beast, so it's sometimes necessary to pass other flags here if you're
				756	doing something sneaky. Some examples:</p>
				757	<p><code>LOCAL_LDLIBS += -lcurses -lpthread<br/>
				758	LOCAL_LDLIBS += -Wl,-z,origin
				759	</code></p>
				760
				761	<h4>LOCAL_NO_MANIFEST</h4>
				762	<p>If your package doesn't have a manifest (AndroidManifest.xml), then
				763	set <code>LOCAL_NO_MANIFEST:=true</code>. The common resources package
				764	does this.</p>
				765
				766	<h4>LOCAL_PACKAGE_NAME</h4>
				767	<p><code>LOCAL_PACKAGE_NAME</code> is the name of an app. For example,
				768	Dialer, Contacts, etc. This will probably change or go away when we switch
				769	to an ant-based build system for the apps.</p>
				770
Tobias Thierer	f795dcb	2018-01-09 20:33:08 +0000	[diff] [blame]	771	<h4>LOCAL_PATCH_MODULE (experimental option)</h4>
				772	<p>As of January 2018, you almost certainly don't need this option, so please
				773	ask and only use it if you understand what you're doing. This feature is
				774	experimental and may go away in future.</p>
				775	<p>
				776	When compiling language level 9+ .java code in packages that are part of a
				777	a system module, <code>LOCAL_PATCH_MODULE</code> names the module that your
				778	sources and dependencies should be patched into. The Android runtime currently
				779	(Jan 2018) doesn't implement the JEP 261 module system so this option is only
				780	supported at compile time. It should only be needed to compile tests in packages
				781	that exist in libcore and which are inconvenient to move elsewhere.
				782	</p>
				783
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	784	<h4>LOCAL_PATH</h4>
				785	<p>The directory your Android.mk file is in. You can set it by putting the
				786	following as the first line in your Android.mk:</p>
				787	<p><code>LOCAL_PATH := $(my-dir)</code></p>
				788	<p>The <code>my-dir</code> macro uses the
				789	<code><a href="http://www.gnu.org/software/make/manual/make.html#MAKEFILE_005fLIST-Variable">MAKEFILE_LIST</a></code>
				790	variable, so you must call it before you include any other makefiles. Also,
				791	consider that any subdirectories you inlcude might reset LOCAL_PATH, so do your
				792	own stuff before you include them. This also means that if you try to write
				793	several <code>include</code> lines that reference <code>LOCAL_PATH</code>,
				794	it won't work, because those included makefiles might reset LOCAL_PATH.
				795
				796	<h4>LOCAL_POST_PROCESS_COMMAND</h4>
				797	<p>For host executables, you can specify a command to run on the module
				798	after it's been linked. You might have to go through some contortions
				799	to get variables right because of early or late variable evaluation:</p>
				800	<p><code>module := $(HOST_OUT_EXECUTABLES)/$(LOCAL_MODULE)<br/>
				801	LOCAL_POST_PROCESS_COMMAND := /Developer/Tools/Rez -d __DARWIN__ -t APPL\<br/>
				802	-d __WXMAC__ -o $(module) Carbon.r
				803	</code></p>
				804
				805	<h4>LOCAL_PREBUILT_EXECUTABLES</h4>
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	806	<p>When including $(BUILD_MULTI_PREBUILT) or $(BUILD_HOST_PREBUILT), set these
				807	to executables that you want copied. They're located automatically into the
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	808	right bin directory.</p>
				809
				810	<h4>LOCAL_PREBUILT_LIBS</h4>
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	811	<p>When including $(BUILD_MULTI_PREBUILT) or $(BUILD_HOST_PREBUILT), set these
				812	to libraries that you want copied. They're located automatically into the
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	813	right lib directory.</p>
				814
				815	<h4>LOCAL_SHARED_LIBRARIES</h4>
				816	<p>These are the libraries you directly link against. You don't need to
				817	pass transitively included libraries. Specify the name without the suffix:</p>
				818	<p><code>LOCAL_SHARED_LIBRARIES := \<br/>
				819	libutils \<br/>
				820	libui \<br/>
				821	libaudio \<br/>
				822	libexpat \<br/>
				823	libsgl
				824	</code></p>
				825
				826	<h4>LOCAL_SRC_FILES</h4>
				827	<p>The build system looks at <code>LOCAL_SRC_FILES</code> to know what source
				828	files to compile -- .cpp .c .y .l .java. For lex and yacc files, it knows
				829	how to correctly do the intermediate .h and .c/.cpp files automatically. If
				830	the files are in a subdirectory of the one containing the Android.mk, prefix
				831	them with the directory name:</p>
				832	<p><code>LOCAL_SRC_FILES := \<br/>
				833	file1.cpp \<br/>
				834	dir/file2.cpp
				835	</code></p>
				836
				837	<h4>LOCAL_STATIC_LIBRARIES</h4>
				838	<p>These are the static libraries that you want to include in your module.
				839	Mostly, we use shared libraries, but there are a couple of places, like
Tom Cherry	6b28af3	2019-04-16 15:18:52 -0700	[diff] [blame]	840	host executables where we use static libraries instead.
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	841	<p><code>LOCAL_STATIC_LIBRARIES := \<br/>
				842	libutils \<br/>
				843	libtinyxml
				844	</code></p>
				845
				846	<h4>LOCAL_MODULE</h4>
				847	<p><code>LOCAL_MODULE</code> is the name of what's supposed to be generated
				848	from your Android.mk. For exmample, for libkjs, the <code>LOCAL_MODULE</code>
				849	is "libkjs" (the build system adds the appropriate suffix -- .so .dylib .dll).
				850	For app modules, use <code>LOCAL_PACKAGE_NAME</code> instead of
				851	<code>LOCAL_MODULE</code>. We're planning on switching to ant for the apps,
				852	so this might become moot.</p>
				853
				854	<h4>LOCAL_MODULE_PATH</h4>
				855	<p>Instructs the build system to put the module somewhere other than what's
				856	normal for its type. If you override this, make sure you also set
				857	<code>LOCAL_UNSTRIPPED_PATH</code> if it's an executable or a shared library
				858	so the unstripped binary has somewhere to go. An error will occur if you forget
				859	to.</p>
				860	<p>See <a href="#moving-modules">Putting modules elsewhere</a> for more.</p>
				861
Colin Cross	639c336	2014-01-24 19:23:40 -0800	[diff] [blame]	862	<h4>LOCAL_MODULE_RELATIVE_PATH</h4>
				863	<p>Instructs the build system to put the module in a subdirectory under the
				864	directory that is normal for its type. If you set this you do not need to
				865	set <code>LOCAL_UNSTRIPPED_PATH</code>, the unstripped binaries will also use
				866	the relative path.</p>
				867	<p>See <a href="#moving-modules">Putting modules elsewhere</a> for more.</p>
				868
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	869	<h4>LOCAL_MODULE_HOST_OS</h4>
				870	<p>This specifies which OSes are supported by this host module. It is not used
				871	for target builds. The accepted values here are combinations of
				872	<code>linux</code>, <code>darwin</code>, and <code>windows</code>. By default,
				873	linux and darwin(MacOS) are considered to be supported. If a module should
				874	build under windows, you must specify windows, and any others to be supported.
				875	Some examples:</p>
				876	<p><code>LOCAL_MODULE_HOST_OS := linux<br/>
				877	LOCAL_MODULE_HOST_OS := darwin linux windows</code></p>
				878
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	879	<h4>LOCAL_UNSTRIPPED_PATH</h4>
				880	<p>Instructs the build system to put the unstripped version of the module
				881	somewhere other than what's normal for its type. Usually, you override this
				882	because you overrode <code>LOCAL_MODULE_PATH</code> for an executable or a
				883	shared library. If you overrode <code>LOCAL_MODULE_PATH</code>, but not
				884	<code>LOCAL_UNSTRIPPED_PATH</code>, an error will occur.</p>
				885	<p>See <a href="#moving-modules">Putting modules elsewhere</a> for more.</p>
				886
				887	<h4>LOCAL_WHOLE_STATIC_LIBRARIES</h4>
				888	<p>These are the static libraries that you want to include in your module without allowing
				889	the linker to remove dead code from them. This is mostly useful if you want to add a static library
				890	to a shared library and have the static library's content exposed from the shared library.
				891	<p><code>LOCAL_WHOLE_STATIC_LIBRARIES := \<br/>
				892	libsqlite3_android<br/>
				893	</code></p>
				894
				895	<h4>LOCAL_YACCFLAGS</h4>
				896	<p>Any flags to pass to invocations of yacc for your module. A known limitation
				897	here is that the flags will be the same for all invocations of YACC for your
				898	module. This can be fixed. If you ever need it to be, just ask.</p>
				899	<p><code>LOCAL_YACCFLAGS := -p kjsyy</code></p>
				900
				901
				902
				903	<h2>Implementation Details</h2>
				904
				905	<p>You should never have to touch anything in the config directory unless
				906	you're adding a new platform, new tools, or adding new features to the
				907	build system. In general, please consult with the build system owner(s)
				908	(<a href="mailto:android-build-team">android-build-team</a>) before you go
				909	mucking around in here. That said, here are some notes on what's going on
				910	under the hood.</p>
				911
				912	<h3>Environment Setup / buildspec.mk Versioning</h3>
				913	<p>In order to make easier for people when the build system changes, when
				914	it is necessary to make changes to buildspec.mk or to rerun the environment
				915	setup scripts, they contain a version number in the variable
				916	BUILD_ENV_SEQUENCE_NUMBER. If this variable does not match what the build
				917	system expects, it fails printing an error message explaining what happened.
				918	If you make a change that requires an update, you need to update two places
				919	so this message will be printed.
				920	<ul>
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	921	<li>In core/envsetup.mk, increment the
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	922	CORRECT_BUILD_ENV_SEQUENCE_NUMBER definition.</li>
				923	<li>In buildspec.mk.default, update the BUILD_ENV_SEQUENCE_DUMBER
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	924	definition to match the one in core/envsetup.mk</li>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	925	</ul>
				926	The scripts automatically get the value from the build system, so they will
				927	trigger the warning as well.
				928	</p>
				929
				930	<h3>Additional makefile variables</h3>
				931	<p>You probably shouldn't use these variables. Please consult
				932	<a href="mailto:android-build-team">android-build-team</a> before using them.
				933	These are mostly there for workarounds for other issues, or things that aren't
				934	completely done right.</p>
				935
				936	<h4>LOCAL_ADDITIONAL_DEPENDENCIES</h4>
				937	<p>If your module needs to depend on anything else that
				938	isn't actually built in to it, you can add those make targets to
				939	<code>LOCAL_ADDITIONAL_DEPENDENCIES</code>. Usually this is a workaround
				940	for some other dependency that isn't created automatically.</p>
				941
				942	<h4>LOCAL_BUILT_MODULE</h4>
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	943	<p class=warning>This should not be used, since multiple binaries are now
				944	created from a single module defintiion.</p>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	945	<p>When a module is built, the module is created in an intermediate
				946	directory then copied to its final location. LOCAL_BUILT_MODULE is
				947	the full path to the intermediate file. See LOCAL_INSTALLED_MODULE
				948	for the path to the final installed location of the module.</p>
				949
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	950	<h4>LOCAL_IS_HOST_MODULE</h4>
				951	<p>Set by the host_xxx.mk includes to tell base_rules.mk and the other
				952	includes that we're building for the host.</p>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	953
				954	<h4>LOCAL_INSTALLED_MODULE</h4>
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	955	<p class=warning>This should not be used, since multiple binaries are now
				956	created from a single module defintiion.</p>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	957	<p>The fully qualified path name of the final location of the module.
				958	See LOCAL_BUILT_MODULE for the location of the intermediate file that
				959	the make rules should actually be constructing.</p>
				960
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	961	<h4>LOCAL_MODULE_CLASS</h4>
				962	<p>Which kind of module this is. This variable is used to construct other
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	963	variable names used to locate the modules. See base_rules.mk and
				964	envsetup.mk.</p>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	965
				966	<h4>LOCAL_MODULE_SUFFIX</h4>
				967	<p>The suffix that will be appended to <code>LOCAL_MODULE</code> to form
				968	<code>LOCAL_MODULE_NAME</code>. For example, .so, .a, .dylib.</p>
				969
				970	<h4>LOCAL_STRIP_MODULE</h4>
Dan Willemsen	0b6c348	2015-09-09 16:51:09 -0700	[diff] [blame]	971	<p>If set to true (the default), the binary will be stripped and a debug
				972	link will be set up so that GDB will still work. If set to no_debuglink,
				973	the binary will be stripped, but no debug link will be added. If set to
				974	keep_symbols, it will strip the debug information, but keep the symbol table.
				975	Any other value will prevent stripping.</p>
Joe Onorato	2303bf0	2008-10-23 19:37:58 -0700	[diff] [blame]	976
				977	<h4>LOCAL_SYSTEM_SHARED_LIBRARIES</h4>
				978	<p>Used while building the base libraries: libc, libm, libdl. Usually
				979	it should be set to "none," as it is in $(CLEAR_VARS). When building
				980	these libraries, it's set to the ones they link against. For example,
				981	libc, libstdc++ and libdl don't link against anything, and libm links against
				982	libc. Normally, when the value is none, these libraries are automatically
				983	linked in to executables and libraries, so you don't need to specify them
				984	manually.</p>
				985
				986
				987	</body>
				988	</html>