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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>LLVM Test Suite Guide</title>
<link rel="stylesheet" href="llvm.css" type="text/css">
</head>
<body>
<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>
<ul>
<li><a href="#codefragments">Code Fragments</a></li>
<li><a href="#wholeprograms">Whole Programs</a></li>
</ul></li>
<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>
</ol>
<p><b>Written by John T. Criswell</b></p>
<!--===============================================================-->
<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>
<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>
% gmake -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>
% gmake -C llvm/test qmtest
</pre>
<p>To run only the tests that compile and execute whole programs, run the
Programs tests:</p>
<pre>
% gmake -C llvm/test/Programs
</pre>
</div>
<!--===============================================================-->
<div class="doc_section"><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"><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>
<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>
<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></li>
</ul></li>
<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"><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>
<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>
<li>mc
<p> Machine code tests. These tests verify that the LLVM assembly
language file can be translated into native assembly code.</p></li>
<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></li>
</ul>
<p>The LLVM database class looks at every file in the Feature directory and
creates a fake test hierarchy containing
<tt>Feature.<testtype>.<testname></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"><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.<value of TEST variable>.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"><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>gmake qmtest</tt> at the
command line in llvm/tests. To run a specific qmtest, suffix the test name with
".t" when running gmake.</p>
<p>For example, to run the Regression.LLC tests, type <tt>gmake
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>gmake</tt>. Alternatively, you can type <tt>gmake TEST=<type>
test</tt> to run one of the specialized tests in
llvm/test/Programs/TEST.<type>.Makefile. For example, you could run the
nightly tester tests using the following commands:</p>
<pre>
% cd llvm/test/Programs
% gmake 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 <program> FAILED message will be displayed. This will help
you separate benign warnings from actual test failures.</p>
</div>
<!-- *********************************************************************** -->
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