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<div class="doc_title">
  LLVM Test Suite Guide
</div>

<ol>
<li><a href="#overview">Overview</a></li>
<li><a href="#Requirements">Requirements</a></li>
<li><a href="#quick">Quick Start</a></li>
<li><a href="#org">LLVM Test Suite Organization</a></li>
<ul>
  <li><a href="#codefragments">Code Fragments</a></li>
  <li><a href="#wholeprograms">Whole Programs</a></li>
</ul>
<li><a href="#tree">LLVM Test Suite Tree</a></li>
<li><a href="#qmstructure">QMTest Structure</a></li>
<li><a href="#progstructure">Programs Structure</a></li>
<li><a href="#run">Running the LLVM Tests</a></li>
<p><b>Written by John T. Criswell</b></p>
</ol>

	<!--===============================================================-->
	<div class="doc_section"><a name="overview">Overview</a></div>
	<!--===============================================================-->

        <div class="doc_text">
	<p>
        This document is the reference manual for the LLVM test suite.  It
	documents the structure of the LLVM test suite, the tools needed to
	use it, and how to add and run tests.
        </p>
        </div>

	<!--===============================================================-->
	<div class="doc_section"><a name="Requirements">Requirements</a></div>
	<!--===============================================================-->

        <div class="doc_text">
        <p>
	In order to use the LLVM test suite, you will need all of the software
	required to build LLVM, plus the following:
        </p>
	<dl compact>
		<dt><A HREF="http://www.qmtest.com">QMTest</A></dt>
		<dd>The LLVM test suite uses QMTest to organize and
                run tests.</dd>

		<dt><A HREF="http://www.python.org">Python</A></dt>
		<dd>You will need a Python interpreter that works with
                QMTest. Python will need zlib and SAX support
                enabled.</dd>
	</dl>
        </div>

	<!--===============================================================-->
	<div class="doc_section"><a name="quick">Quick Start</a></div>
	<!--===============================================================-->

        <div class="doc_text">
        <p>
        The tests are located in the LLVM source tree under the directory
        <tt>llvm/test</tt>. To run all of the tests in LLVM, use the Master
        Makefile in that directory:
	</p>
	<pre>
	 % make -C llvm/test
	</pre>

	<p>
	To run only the code fragment tests (i.e. those that do basic testing of
	LLVM), run the tests organized by QMTest:
	</p>

	<pre>
	 % make -C llvm/test qmtest
	</pre>

	<p>
	To run only the tests that compile and execute whole programs, run the
	Programs tests:
	</p>

	<pre>
	 % make -C llvm/test/Programs
	</pre>
        </div>

	<!--===============================================================-->
	<div class="doc_section"><h2><a name="org">LLVM Test Suite
        Organization </a></div>
	<!--===============================================================-->

        <div class="doc_text">
	<p>The LLVM test suite contains two major categories of tests: code
        fragments and whole programs.</p>
        </div>

        <div class="doc_subsection"><a name="codefragments">Code Fragments</a> 
        </div>

        <div class="doc_text">
                <p>
		Code fragments are small pieces of code that test a specific
		feature of LLVM or trigger a specific bug in LLVM.  They are
		usually written in LLVM assembly language, but can be
		written in other languages if the test targets a
                particular language front end.
		</p><p>
		Code fragments are not complete programs, and they are
                never executed to determine correct behavior.
		</p><p>
		The tests in the Features and
                Regression directories contain code fragments.
                </p>
        </div>

        <div class="doc_subsection"><a name="wholeprograms">Whole Programs</a> 
        </div>

        <div class="doc_text">
		<p>
                Whole Programs are pieces of code which can be compiled and
                linked into a stand-alone program that can be executed.  These
                programs are generally written in high level languages such as C
                or C++, but sometimes they are written straight in LLVM
                assembly.
		</p><p>
		These programs are compiled and then executed using several
		different methods (native compiler, LLVM C backend, LLVM JIT,
		LLVM native code generation, etc).  The output of these programs
		is compared to ensure that LLVM is compiling the program
		correctly.
		</p><p>
		In addition to compiling and executing programs, whole program
		tests serve as a way of benchmarking LLVM performance, both in
		terms of the efficiency of the programs generated as well as the
		speed with which LLVM compiles, optimizes, and generates code.
		</p><p>
		The Programs directory contains all tests which compile and
		benchmark whole programs.
                </p>
        </div>

	<!--===============================================================-->
	<div class="doc_section"><h2><a name="tree">LLVM Test Suite Tree</a>
        </div>
	<!--===============================================================-->

        <div class="doc_text">
	<p>Each type of test in the LLVM test suite has its own directory. The
        major subtrees of the test suite directory tree are as follows:</p>
        
	<ul>
		<li>Features
		<p>
                This directory contains sample codes that test various features
		of the LLVM language.  These pieces of sample code are run
		through various assembler, disassembler, and optimizer passes.
		</p>

		<li>Regression
                <p>
		This directory contains regression tests for LLVM.  When a bug
		is found in LLVM, a regression test containing just enough
		code to reproduce the problem should be written and placed
		somewhere underneath this directory.  In most cases, this
		will be a small piece of LLVM assembly language code, often
		distilled from an actual application or benchmark.
		</p>

		<li>Programs
		<p>
                The Programs directory contains programs that can be compiled
		with LLVM and executed.  These programs are compiled using the
		native compiler and various LLVM backends.  The output from the
		program compiled with the native compiler is assumed correct;
		the results from the other programs are compared to the native
		program output and pass if they match.
		</p><p>
		In addition for testing correctness, the Programs directory
		also performs timing tests of various LLVM optimizations.
		It also records compilation times for the compilers and the
		JIT.  This information can be used to compare the
		effectiveness of LLVM's optimizations and code generation.
		</p><p>
		The Programs directory is subdivided into several smaller
		subdirectories:
                </p>

		<ul>
			<li>Programs/SingleSource
                        <p>
			The SingleSource directory contains test programs that
			are only a single source file in size.  These are
			usually small benchmark programs or small programs that
			calculate a particular value.  Several such programs are
			grouped together in each directory.
			</p>

			<li>Programs/MultiSource
                        <p>
                        The MultiSource directory contains subdirectories which
                        contain entire programs with multiple source files.
                        Large benchmarks and whole applications go here.
			</p>

			<li>Programs/External
                        <p>
			The External directory contains Makefiles for building
			code that is external to (i.e. not distributed with)
			LLVM.  The most prominent member of this directory is
			the SPEC 2000 benchmark suite.  The presence and
			location of these external programs is configured by the
			LLVM <tt>configure</tt> script.
                        </p>
		</ul>

		<p>

		<li>QMTest
                <p>
		This directory contains the QMTest information files.  Inside
		this directory are QMTest administration files and the Python
		code that implements the LLVM test and database classes.
                </p>
	</ul>
        </div>

	<!--===============================================================-->
	<div class="doc_section"><h2><a name="qmstructure">QMTest Structure</a>
        </div>
	<!--===============================================================-->

        <div class="doc_text">
	<p>
        The LLVM test suite is partially driven by QMTest and partially
	driven by GNU Make.  Specifically, the Features and Regression tests
	are all driven by QMTest.  The Programs directory is currently
	driven by a set of Makefiles.
	</p><p>
	The QMTest system needs to have several pieces of information
	available; these pieces of configuration information are known
	collectively as the "context" in QMTest parlance.  Since the context
	for LLVM is relatively large, the master Makefile in llvm/test
	sets it for you.
	</p><p>
	The LLVM database class makes the subdirectories of llvm/test a
	QMTest test database.  For each directory that contains tests driven by
	QMTest, it knows what type of test the source file is and how to run it.
	</p><p>
	Hence, the QMTest namespace is essentially what you see in the
	Feature and Regression directories, but there is some magic that
	the database class performs (as described below).
	</p><p>
	The QMTest namespace is currently composed of the following tests and
	test suites:
        </p>

	<ul>
		<li>Feature
                <p>
		These are the feature tests found in the Feature directory.
		They are broken up into the following categories:
                </p>
		<ul>
			<li>ad
			<p>
			Assembler/Disassembler tests.  These tests verify that a
			piece of LLVM assembly language can be assembled into
			bytecode and then disassembled into the original
			assembly language code.  It does this several times to
			ensure that assembled output can be disassembled and
			disassembler output can be assembled.  It also verifies
			that the give assembly language file can be assembled
			correctly.
                        </p>

			<li>opt
			<p>
			Optimizer tests.  These tests verify that two of the
			optimizer passes completely optimize a program (i.e.
			after a single pass, they cannot optimize a program
			any further).
			</p>

			<li>mc
			<p>
			Machine code tests.  These tests verify that the LLVM
			assembly language file can be translated into native
			assembly code.
			</p>

			<li>cc
			<p>
			C code tests.  These tests verify that the specified
			LLVM assembly code can be converted into C source code
			using the C backend.
                        </p>
		</ul>

		<p>
		The LLVM database class looks at every file in the Feature
		directory and creates a fake test hierarchy containing
		<tt>Feature.&lt;testtype&gt;.&lt;testname&gt;</tt>.  So, if you
		add an LLVM assembly language file to the Feature directory, it
		actually creates 5 new tests: assembler/disassembler, assembler,
		optimizer, machine code, and C code.
                </p>

		<li>Regression
                <p>
		These are the regression tests.  There is one suite for each
		subdirectory of the Regression directory.  If you add a new
		subdirectory there, you will need to modify, at least, the
		<tt>RegressionMap</tt> variable in <tt>QMTest/llvmdb.py</tt> so
		that QMTest knows how to run the tests in the new subdirectory.
                </p>
	</ul>
        </div>

	<!--===============================================================-->
	<div class="doc_section"><h2><a name="progstructure">Programs
        Structure</a></div>
	<!--===============================================================-->

        <div class="doc_text">
        <p>
	As mentioned previously, the Programs tree in llvm/test provides three
	types of tests: MultiSource, SingleSource, and External.  Each tree is
	then subdivided into several categories, including applications,
	benchmarks, regression tests, code that is strange grammatically, etc.
	These organizations should be relatively self explanatory.
	</p><p>
	In addition to the regular Programs tests, the Programs tree also
	provides a mechanism for compiling the programs in different ways.  If
	the variable TEST is defined on the gmake command line, the test system
	will include a Makefile named <tt>TEST.&lt;value of TEST
	variable&gt;.Makefile</tt>.  This Makefile can modify build rules to
        yield different results.
	</p><p>
	For example, the LLVM nightly tester uses <tt>TEST.nightly.Makefile</tt>
        to create the nightly test reports.  To run the nightly tests, run
	<tt>gmake TEST=nightly</tt>.
	</p><p>
	There are several TEST Makefiles available in the tree.  Some of them
	are designed for internal LLVM research and will not work outside of the
	LLVM research group.  They may still be valuable, however, as a guide to
	writing your own TEST Makefile for any optimization or analysis passes
	that you develop with LLVM.
        </p>
        </div>

	<!--===============================================================-->
	<div class="doc_section"><h2><a name="run">Running the LLVM Tests</a>
        </div>
	<!--===============================================================-->

        <div class="doc_text">
        <p>
	First, all tests are executed within the LLVM object directory tree.
	They <i>are not</i> executed inside of the LLVM source tree.  This is
	because the test suite creates temporary files during execution.
	</p><p>
	The master Makefile in llvm/test is capable of running both the
	QMTest driven tests and the Programs tests.  By default, it will run
	all of the tests.
	</p><p>
	To run only the QMTest driven tests, run <tt>make qmtest</tt> at the
	command line in llvm/tests.  To run a specific qmtest, suffix the test
	name with ".t" when running make.
	</p><p>
	For example, to run the Regression.LLC tests, type
	<tt>make Regression.LLC.t</tt> in llvm/tests.
	</p><p>
	Note that the Makefiles in llvm/test/Features and llvm/test/Regression
	are gone.  You must now use QMTest from the llvm/test directory to run
	them.
	</p><p>
	To run the Programs test, cd into the llvm/test/Programs directory and
	type <tt>make</tt>.  Alternatively, you can type <tt>make
	TEST=&lt;type&gt; test</tt> to run one of the specialized tests in
	llvm/test/Programs/TEST.&lt;type&gt;.Makefile.  For example, you could
	run the nightly tester tests using the following commands:
	</p>

	<pre>
	 % cd llvm/test/Programs
	 % make TEST=nightly test
	</pre>

	<p>
	Regardless of which test you're running, the results are printed on
	standard output and standard error.  You can redirect these results to a
	file if you choose.
	</p><p>
	Some tests are known to fail.  Some are bugs that we have not fixed yet;
	others are features that we haven't added yet (or may never add).  In
	QMTest, the result for such tests will be XFAIL (eXpected FAILure).  In
	this way, you can tell the difference between an expected and unexpected
	failure.
	</p><p>
	The Programs tests have no such feature as of this time.  If the test
	passes, only warnings and other miscellaneous output will be generated.
	If a test fails, a large &lt;program&gt; FAILED message will be
	displayed.  This will help you separate benign warnings from actual test
	failures.
        </p>
        </div>

<!-- *********************************************************************** -->

<hr><font size="-1">
<address>John T. Criswell</address>
<a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a>
<br>
Last modified: $Date$
</font>

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