This document is the reference manual for the LLVM testing infrastructure. It documents the structure of the LLVM testing infrastructure, the tools needed to use it, and how to add and run tests.

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

DejaGNU

The Feature and Regressions tests are organized and run by DejaGNU.

Expect

Expect is required by DejaGNU.

tcl

Tcl is required by DejaGNU.

F2C

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.

Darwin (Mac OS X) developers can simplify the installation of Expect and tcl by using fink. fink install expect will install both. Alternatively, Darwinports users can use sudo port install expect to install Expect and tcl.

The LLVM testing infrastructure contains two major categories of tests: code fragments and whole programs. Code fragments are referred to as the "DejaGNU tests" and are in the llvm module in subversion under the llvm/test directory. The whole programs tests are referred to as the "Test suite" and are in the test-suite module in subversion.

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. These tests are driven by the DejaGNU testing framework, which is hidden behind a few simple makefiles.

These code fragments are not complete programs. The code generated from them is never executed to determine correct behavior.

These code fragment tests are located in the llvm/test directory.

Typically 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.

The test suite contains whole programs, which 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.

The test-suite is located in the test-suite Subversion module.

The tests are located in two separate Subversion modules. The DejaGNU tests are in the main "llvm" module under the directory llvm/test (so you get these tests for free with the main llvm tree). The more comprehensive test suite that includes whole programs in C and C++ is in the test-suite module. This module should be checked out to the llvm/projects directory (don't use another name then the default "test-suite", for then the test suite will be run every time you run make in the main llvm directory). When you configure the llvm module, the test-suite directory will be automatically configured. Alternatively, you can configure the test-suite 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

or

% gmake check

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

% gmake TESTSUITE=Transforms check

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 only a single test, set TESTONE to its path (relative to llvm/test) and make the check-one target:

% gmake TESTONE=Feature/basictest.ll check-one

To run the comprehensive test suite (tests that compile and execute whole programs), first checkout and setup the test-suite module:

% cd llvm/projects
% svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite
% cd ..
% ./configure --with-llvmgccdir=$LLVM_GCC_DIR

Then, run the entire test suite by running make in the test-suite directory:

% cd projects/test-suite
% gmake

Usually, running the "nightly" set of tests is a good idea, and you can also let it generate a report by running:

% cd projects/test-suite
% gmake TEST=nightly report report.html

Any of the above commands can also be run in a subdirectory of projects/test-suite to run the specified test only on the programs in that subdirectory.

The LLVM DejaGNU tests are driven by DejaGNU together with GNU Make and are located in the llvm/test directory.

This directory contains a large array of small tests that exercise various features of LLVM and to ensure that regressions do not occur. The directory is broken into several sub-directories, each focused on a particular area of LLVM. A few of the important ones are:

• Analysis: checks Analysis passes.
• Archive: checks the Archive library.
• Assembler: checks Assembly reader/writer functionality.
• Bitcode: checks Bitcode reader/writer functionality.
• CodeGen: checks code generation and each target.
• Features: checks various features of the LLVM language.
• Linker: tests bitcode linking.
• Transforms: tests each of the scalar, IPO, and utility transforms to ensure they make the right transformations.
• Verifier: tests the IR verifier.

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. DejaGNU looks for this file to determine how to run the tests. This file is just a Tcl script and it can do anything you want, but we've standardized it for the LLVM regression tests. If you're adding a directory of tests, just copy dg.exp from another directory to get running. The standard dg.exp simply loads a Tcl library (test/lib/llvm.exp) and calls the llvm_runtests function defined in that library with a list of file names to run. The names are obtained by using Tcl's glob command. Any directory that contains only directories does not need the dg.exp file.

The llvm-runtests function lookas at each file that is passed to it and gathers any lines together that match "RUN:". This are the "RUN" lines that specify how the test is to be run. So, each test script must contain RUN lines if it is to do anything. If there are no RUN lines, the llvm-runtests function will issue an error and the test will fail.

RUN lines are specified in the comments of the test program using the keyword RUN followed by a colon, and lastly the command (pipeline) to execute. Together, these lines form the "script" that llvm-runtests executes to run the test case. The syntax of the RUN lines is similar to a shell's syntax for pipelines including I/O redirection and variable substitution. However, even though these lines may look like a shell script, they are not. RUN lines are interpreted directly by the Tcl exec command. They are never executed by a shell. Consequently the syntax differs from normal shell script syntax in a few ways. You can specify as many RUN lines as needed.

Each RUN line is executed on its own, distinct from other lines unless its last character is \. This continuation character causes the RUN line to be concatenated with the next one. In this way you can build up long pipelines of commands without making huge line lengths. The lines ending in \ are concatenated until a RUN line that doesn't end in \ is found. This concatenated set of RUN lines then constitutes one execution. Tcl will substitute variables and arrange for the pipeline to be executed. If any process in the pipeline fails, the entire line (and test case) fails too.

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

As with a Unix shell, the RUN: lines permit pipelines and I/O redirection to be used. However, the usage is slightly different than for Bash. To check what's legal, see the documentation for the Tcl exec command and the tutorial. The major differences are:

• You can't do 2>&1. That will cause Tcl to write to a file named &1. Usually this is done to get stderr to go through a pipe. You can do that in tcl with |& so replace this idiom: ... 2>&1 | grep with ... |& grep
• You can only redirect to a file, not to another descriptor and not from a here document.
• tcl supports redirecting to open files with the @ syntax but you shouldn't use that here.

There are some quoting rules that you must pay attention to when writing your RUN lines. In general nothing needs to be quoted. Tcl won't strip off any ' or " so they will get passed to the invoked program. For example:

... | grep 'find this string'

This will fail because the ' characters are passed to grep. This would instruction grep to look for 'find in the files this and string'. To avoid this use curly braces to tell Tcl that it should treat everything enclosed as one value. So our example would become:

... | grep {find this string}

Additionally, the characters [ and ] are treated specially by Tcl. They tell Tcl to interpret the content as a command to execute. Since these characters are often used in regular expressions this can have disastrous results and cause the entire test run in a directory to fail. For example, a common idiom is to look for some basicblock number:

... | grep bb[2-8]

This, however, will cause Tcl to fail because its going to try to execute a program named "2-8". Instead, what you want is this:

... | grep {bb\[2-8\]}

Finally, if you need to pass the \ character down to a program, then it must be doubled. This is another Tcl special character. So, suppose you had:

... | grep 'i32\*'

This will fail to match what you want (a pointer to i32). First, the ' do not get stripped off. Second, the \ gets stripped off by Tcl so what grep sees is: 'i32*'. That's not likely to match anything. To resolve this you must use \\ and the {}, like this:

... | grep {i32\\*}

With a RUN line there are a number of substitutions that are permitted. In general, any Tcl variable that is available in the substitute function (in test/lib/llvm.exp) can be substituted into a RUN line. To make a substitution just write the variable's name preceded by a $. Additionally, for compatibility reasons with previous versions of the test library, certain names can be accessed with an alternate syntax: a % prefix. These alternates are deprecated and may go away in a future version.

Here are the available variable names. The alternate syntax is listed in parentheses.

$test (%s)

The full path to the test case's source. This is suitable for passing on the command line as the input to an llvm tool.

$srcdir

The source directory from where the "make check" was run.

objdir

The object directory that corresponds to the $srcdir.

subdir

A partial path from the test directory that contains the sub-directory that contains the test source being executed.

srcroot

The root directory of the LLVM src tree.

objroot

The root directory of the LLVM object tree. This could be the same as the srcroot.

path

The path to the directory that contains the test case source. This is for locating any supporting files that are not generated by the test, but used by the test.

tmp

The path to a temporary file name that could be used for this test case. The file name won't conflict with other test cases. You can append to it if you need multiple temporaries. This is useful as the destination of some redirected output.

llvmlibsdir (%llvmlibsdir)

The directory where the LLVM libraries are located.

target_triplet (%target_triplet)

The target triplet that corresponds to the current host machine (the one running the test cases). This should probably be called "host".

prcontext (%prcontext)

Path to the prcontext tcl script that prints some context around a line that matches a pattern. This isn't strictly necessary as the test suite is run with its PATH altered to include the test/Scripts directory where the prcontext script is located. Note that this script is similar to grep -C but you should use the prcontext script because not all platforms support grep -C.

llvmgcc (%llvmgcc)

The full path to the llvm-gcc executable as specified in the configured LLVM environment

llvmgxx (%llvmgxx)

The full path to the llvm-gxx executable as specified in the configured LLVM environment

llvmgcc_version (%llvmgcc_version)

The full version number of the llvm-gcc executable.

llvmgccmajvers (%llvmgccmajvers)

The major version number of the llvm-gcc executable.

gccpath

The full path to the C compiler used to build LLVM. Note that this might not be gcc.

gxxpath

The full path to the C++ compiler used to build LLVM. Note that this might not be g++.

compile_c (%compile_c)

The full command line used to compile LLVM C source code. This has all the configured -I, -D and optimization options.

compile_cxx (%compile_cxx)

The full command used to compile LLVM C++ source code. This has all the configured -I, -D and optimization options.

link (%link)

This full link command used to link LLVM executables. This has all the configured -I, -L and -l options.

shlibext (%shlibext)

The suffix for the host platforms share library (dll) files. This includes the period as the first character.

To add more variables, two things need to be changed. First, add a line in the test/Makefile that creates the site.exp file. This will "set" the variable as a global in the site.exp file. Second, in the test/lib/llvm.exp file, in the substitute proc, add the variable name to the list of "global" declarations at the beginning of the proc. That's it, the variable can then be used in test scripts.

To make RUN line writing easier, there are several shell scripts located in the llvm/test/Scripts directory. This directory is in the PATH when running tests, so you can just call these scripts using their name. For example:

ignore

This script runs its arguments and then always returns 0. This is useful in cases where the test needs to cause a tool to generate an error (e.g. to check the error output). However, any program in a pipeline that returns a non-zero result will cause the test to fail. This script overcomes that issue and nicely documents that the test case is purposefully ignoring the result code of the tool

not

This script runs its arguments and then inverts the result code from it. Zero result codes become 1. Non-zero result codes become 0. This is useful to invert the result of a grep. For example "not grep X" means succeed only if you don't find X in the input.

Sometimes it is necessary to mark a test case as "expected fail" or XFAIL. You can easily mark a test as XFAIL just by including XFAIL: on a line near the top of the file. This signals that the test case should succeed if the test fails. Such test cases are counted separately by DejaGnu. To specify an expected fail, use the XFAIL keyword in the comments of the test program followed by a colon and one or more regular expressions (separated by a comma). The regular expressions allow you to XFAIL the test conditionally by host platform. The regular expressions following the : are matched against the target triplet or llvmgcc version number for the host machine. If there is a match, the test is expected to fail. If not, the test is expected to succeed. To XFAIL everywhere just specify XFAIL: *. When matching the llvm-gcc version, you can specify the major (e.g. 3) or full version (i.e. 3.4) number. Here is an example of an XFAIL line:

; XFAIL: darwin,sun,llvmgcc4

To make the output more useful, the llvm_runtest function wil scan the lines of the test case for ones that contain a pattern that matches PR[0-9]+. This is the syntax for specifying a PR (Problem Report) number that is related to the test case. The number after "PR" specifies the LLVM bugzilla number. When a PR number is specified, it will be used in the pass/fail reporting. This is useful to quickly get some context when a test fails.

Finally, any line that contains "END." will cause the special interpretation of lines to terminate. This is generally done right after the last RUN: line. This has two side effects: (a) it prevents special interpretation of lines that are part of the test program, not the instructions to the test case, and (b) it speeds things up for really big test cases by avoiding interpretation of the remainder of the file.

The test-suite module contains a number of 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.

When executing tests, it is usually a good idea to start out with a subset of the available tests or programs. This makes test run times smaller at first and later on this is useful to investigate individual test failures. To run some test only on a subset of programs, simply change directory to the programs you want tested and run gmake there. Alternatively, you can run a different test using the TEST variable to change what tests or run on the selected programs (see below for more info).

In addition for testing correctness, the llvm-test 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.

llvm-test tests are divided into three types of tests: MultiSource, SingleSource, and External.

• llvm-test/SingleSource

  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.

• llvm-test/MultiSource

  The MultiSource directory contains subdirectories which contain entire programs with multiple source files. Large benchmarks and whole applications go here.

• llvm-test/External

  The External directory contains Makefiles for building code that is external to (i.e., not distributed with) LLVM. The most prominent members of this directory are the SPEC 95 and SPEC 2000 benchmark suites. The External directory does not contain these actual tests,but only the Makefiles that know how to properly compile these programs from somewhere else. The presence and location of these external programs is configured by the llvm-test configure script.

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.

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 the test suite 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.

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.

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

1. cd into the llvm/projects directory

2. Check out the test-suite module with:

   % svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite
   

   This will get the test suite into llvm/projects/llvm-test

3. Configure the test suite using llvm configure. This will automatically configure test-suite. You must do it from the top level otherwise llvm-gcc will not be set which is required to run llvm-test:

   % cd $LLVM_OBJ_ROOT ; $LLVM_SRC_ROOT/configure --with-llvmgccdir=$LLVM_GCC_DIR
   

   Note that that $LLVM_GCC_DIR is the directory where you installed llvm-gcc, not its src or obj directory.

4. Change back to the llvm/projects/test-suite directory you created before and run gmake (or just "make" on systems where GNU make is the default, such as linux.

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).

% cd llvm/projects/test-suite/MultiSource/Benchmarks  # or some other level
% make TEST=libcalls report

Name                                  | total | #exit |
...
FreeBench/analyzer/analyzer           | 51    | 6     | 
FreeBench/fourinarow/fourinarow       | 1     | 1     | 
FreeBench/neural/neural               | 19    | 9     | 
FreeBench/pifft/pifft                 | 5     | 3     | 
MallocBench/cfrac/cfrac               | 1     | *     | 
MallocBench/espresso/espresso         | 52    | 12    | 
MallocBench/gs/gs                     | 4     | *     | 
Prolangs-C/TimberWolfMC/timberwolfmc  | 302   | *     | 
Prolangs-C/agrep/agrep                | 33    | 12    | 
Prolangs-C/allroots/allroots          | *     | *     | 
Prolangs-C/assembler/assembler        | 47    | *     | 
Prolangs-C/bison/mybison              | 74    | *     | 
...

#!/bin/bash
BASE=/proj/work/llvm/nightlytest
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/NewNightlyTest.pl .
nice ./NewNightlyTest.pl -nice -release -verbose -parallel -enable-linscan \
   -nickname NightlyTester -noexternals > output.log 2>&1 

John T. Criswell, Reid Spencer, and Tanya Lattner
The LLVM Compiler Infrastructure
Last modified: $Date: 2008/11/10 05:54:43 $