LLVM Test Suite Guide
  1. Overview
  2. Requirements
  3. Quick Start
  4. LLVM Test Suite Organization
  5. LLVM Test Suite Tree
  6. DejaGNU Structure
  7. llvm-test Structure
  8. Running the LLVM Tests
  9. Running the nightly tester

Written by John T. Criswell, Reid Spencer, and Tanya Lattner


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.


In order to use the LLVM test suite, you will need all of the software required to build LLVM, plus the following:

The Feature and Regressions tests are organized and run by DejaGNU.
Expect is required by DejaGNU.
Tcl is required by DejaGNU.
For now, LLVM does not have a Fortran front-end, but using F2C, we can run Fortran benchmarks. F2C support must be enabled via configure if not installed in a standard place. F2C requires three items: the f2c executable, f2c.h to compile the generated code, and libf2c.a to link generated code. By default, given an F2C directory $DIR, the configure script will search $DIR/bin for f2c, $DIR/include for f2c.h, and $DIR/lib for libf2c.a. The default $DIR values are: /usr, /usr/local, /sw, and /opt. If you installed F2C in a different location, you must tell configure:
  • ./configure --with-f2c=$DIR
    This will specify a new $DIR for the above-described search process. This will only work if the binary, header, and library are in their respective subdirectories of $DIR.
  • ./configure --with-f2c-bin=/binary/path --with-f2c-inc=/include/path --with-f2c-lib=/lib/path
    This allows you to specify the F2C components separately. Note: if you choose this route, you MUST specify all three components, and you need to only specify directories where the files are located; do NOT include the filenames themselves on the configure line.
Quick Start

The tests are located in two separate CVS modules. The basic feature and regression tests are in the main "llvm" module under the directory llvm/test. A more comprehensive test suite that includes whole programs in C and C++ is in the llvm-test module. This module should be checked out to the llvm/projects directory. When you configure the llvm module, the llvm-test module will be automatically configured. Alternatively, you can configure the llvm-test module manually.

To run all of the simple tests in LLVM using DejaGNU, use the master Makefile in the llvm/test directory:

% gmake -C llvm/test
% gmake check

To run only a subdirectory of tests in llvm/test using DejaGNU (ie. Regression/Transforms), just set the TESTSUITE variable to the path of the subdirectory (relative to llvm/test):

% gmake -C llvm/test TESTSUITE=Regression/Transforms

Note: If you are running the tests with objdir != subdir, you must have run the complete testsuite before you can specify a subdirectory.

To run the comprehensive test suite (tests that compile and execute whole programs), run the llvm-test tests:

% cd llvm/projects
% cvs co llvm-test
% cd llvm-test
% ./configure --with-llvmsrc=$LLVM_SRC_ROOT --with-llvmobj=$LLVM_OBJ_ROOT
% gmake
LLVM Test Suite Organization

The LLVM test suite contains two major categories of tests: code fragments and whole programs. Code fragments are in the llvm module under the llvm/test directory. The whole programs test suite is in the llvm-test module under the main directory.

Code Fragments

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.

Code fragments are not complete programs, and they are never executed to determine correct behavior.

These code fragment tests are located in the llvm/test/Features and llvm/test/Regression directories.

Whole Programs

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.

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.

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.

All "whole program" tests are located in the llvm-test CVS module.

LLVM Test Suite Tree

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:

DejaGNU Structure

The LLVM test suite is partially driven by DejaGNU and partially driven by GNU Make. Specifically, the Features and Regression tests are all driven by DejaGNU. The llvm-test module is currently driven by a set of Makefiles.

The DejaGNU structure is very simple, but does require some information to be set. This information is gathered via configure and is written to a file, site.exp in llvm/test. The llvm/test Makefile does this work for you.

In order for DejaGNU to work, each directory of tests must have a dg.exp file. This file is a program written in tcl that calls the llvm-runtests procedure on each test file. The llvm-runtests procedure is defined in llvm/test/lib/llvm-dg.exp. Any directory that contains only directories does not need the dg.exp file.

In order for a test to be run, it must contain information within the test file on how to run the test. These are called RUN lines. Run lines are specified in the comments of the test program using the keyword RUN followed by a colon, and lastly the commands to execute. These commands will be executed in a bash script, so any bash syntax is acceptable. You can specify as many RUN lines as necessary. Each RUN line translates to one line in the resulting bash script. Below is an example of legal RUN lines in a .ll file:

; RUN: llvm-as < %s | llvm-dis > %t1
; RUN: llvm-dis < %s.bc-13 > %t2
; RUN: diff %t1 %t2

There are a couple patterns within a RUN line that the llvm-runtest procedure looks for and replaces with the appropriate syntax:

The path to the source directory. This is for locating any supporting files that are not generated by the test, but used by the test.
The test file.
Temporary filename: testscript.test_filename.tmp, where test_filename is the name of the test file. All temporary files are placed in the Output directory within the directory the test is located.
Path to a script that performs grep -C. Use this since not all platforms support grep -C.
Full path to the llvm-gcc executable.
Full path to the llvm-g++ executable.

There are also several scripts in the llvm/test/Scripts directory that you might find useful when writing RUN lines.

Lastly, you can easily mark a test that is expected to fail on a specific platform by using the XFAIL keyword. Xfail lines are specified in the comments of the test program using XFAIL, followed by a colon, and one or more regular expressions (separated by a comma) that will match against the target triplet for the machine. You can use * to match all targets. Here is an example of an XFAIL line:

; XFAIL: darwin,sun
llvm-test Structure

As mentioned previously, the llvm-test module 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.

In addition to the regular "whole program" tests, the llvm-test module 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 TEST.<value of TEST variable>.Makefile. This Makefile can modify build rules to yield different results.

For example, the LLVM nightly tester uses TEST.nightly.Makefile to create the nightly test reports. To run the nightly tests, run gmake TEST=nightly.

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.

Note, when configuring the llvm-test module, you might want to specify the following configuration options:

Enable the use of SPEC2000 when testing LLVM. This is disabled by default (unless configure finds SPEC2000 installed). By specifying directory, you can tell configure where to find the SPEC2000 benchmarks. If directory is left unspecified, configure uses the default value /home/vadve/shared/benchmarks/speccpu2000/benchspec.

Enable the use of SPEC95 when testing LLVM. It is similar to the --enable-spec2000 option.

Enable the use of Povray as an external test. Versions of Povray written in C should work. This option is similar to the --enable-spec2000 option.
Running the LLVM Tests

First, all tests are executed within the LLVM object directory tree. They are not executed inside of the LLVM source tree. This is because the test suite creates temporary files during execution.

The master Makefile in llvm/test is capable of running only the DejaGNU driven tests. By default, it will run all of these tests.

To run only the DejaGNU driven tests, run gmake at the command line in llvm/test. To run a specific directory of tests, use the TESTSUITE variable.

For example, to run the Regression tests, type gmake TESTSUITE=Regression in llvm/tests.

Note that there are no Makefiles in llvm/test/Features and llvm/test/Regression. You must use DejaGNU from the llvm/test directory to run them.

To run the llvm-test suite, you need to use the following steps:

  1. cd into the llvm/projects directory
  2. check out the llvm-test module with:
    cvs -d :pserver:anon@llvm.cs.uiuc.edu:/var/cvs/llvm co -PR llvm-test
    This will get the test suite into llvm/projects/llvm-test
  3. configure the test suite. You can do this one of two ways:
    1. Use the regular llvm configure:
      cd $LLVM_OBJ_ROOT ; $LLVM_SRC_ROOT/configure
      This will ensure that the projects/llvm-test directory is also properly configured.
    2. Use the configure script found in the llvm-test source directory:
      $LLVM_SRC_ROOT/projects/llvm-test/configure --with-llvmsrc=$LLVM_SRC_ROOT --with-llvmobj=$LLVM_OBJ_ROOT
  4. gmake

Note that the second and third steps only need to be done once. After you have the suite checked out and configured, you don't need to do it again (unless the test code or configure script changes).

To make a specialized test (use one of the llvm-test/TEST.<type>.Makefiles), just run:
gmake TEST=<type> test
For example, you could run the nightly tester tests using the following commands:

 % cd llvm/projects/llvm-test
 % gmake TEST=nightly test

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.

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 DejaGNU, the result for such tests will be XFAIL (eXpected FAILure). In this way, you can tell the difference between an expected and unexpected failure.

The tests in llvm-test have no such feature at 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.

Running the nightly tester

The LLVM Nightly Testers automatically check out an LLVM tree, build it, run the "nightly" program test (described above), run all of the feature and regression tests, and then delete the checked out tree. This tester is designed to ensure that programs don't break as well as keep track of LLVM's progress over time.

If you'd like to set up an instance of the nightly tester to run on your machine, take a look at the comments at the top of the utils/NightlyTester.pl file. We usually run it from a crontab entry that looks ilke this:

5 3 * * *  $HOME/llvm/utils/NightlyTest.pl -parallel $CVSROOT $HOME/buildtest-X86 $HOME/cvs/testresults-X86

Or, you can create a shell script to encapsulate the running of the script. The optimized x86 Linux nightly test is run from just such a script:

export CVSROOT=:pserver:anon@llvm.cs.uiuc.edu:/var/cvs/llvm
export BUILDDIR=$BASE/build 
export WEBDIR=$BASE/testresults 
export LLVMGCCDIR=/proj/work/llvm/cfrontend/install
export PATH=/proj/install/bin:$LLVMGCCDIR/bin:$PATH
export LD_LIBRARY_PATH=/proj/install/lib
cd $BASE
cp /proj/work/llvm/llvm/utils/NightlyTest.pl .
nice ./NightlyTest.pl -nice -release -verbose -parallel -enable-linscan -noexternals 2>&1 > output.log
mail -s 'X86 nightly tester results' llvm-testresults@cs.uiuc.edu < output.log

Take a look at the NightlyTest.pl file to see what all of the flags and strings do. If you start running the nightly tests, please let us know and we'll link your page to the global tester page. Thanks!

Valid CSS! Valid HTML 4.01! John T. Criswell, Reid Spencer, and Tanya Lattner
The LLVM Compiler Infrastructure
Last modified: $Date: 2005/05/18 16:04:43 $