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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<link rel="stylesheet" href="llvm.css" type="text/css" media="screen" />
<title>LLVM Test Suite Guide</title>
</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></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.<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"><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.<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"><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=<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
% 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 <program> 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>
Last modified: $Date$
</font>
</body>
</html>
|
