LLVM Testing Infrastructure Guide

The LLVM testing infrastructure contains two major categories of tests: regression tests and whole programs. The regression tests are contained inside the LLVM repository itself under llvm/test and are expected to always -pass -- they should be run before every commit. The whole programs tests are -referred to as the "LLVM test suite" and are in the test-suite module -in subversion. -

The whole programs tests are referred to as the "LLVM test suite" (or +"test-suite") and are in the test-suite module in subversion. For +historical reasons, these tests are also referred to as the "nightly tests" in +places, which is less ambiguous than "test-suite" and remains in use although we +run them much more often than nightly.

Regression tests

Test suite

test-suite

Test suite

Debugging Information tests

@@ -355,18 +299,18 @@ clang/test directory.

you.

In order for the regression tests to work, each directory of tests must - have a dg.exp file. Lit 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, + have a lit.local.cfg file. Lit looks for this file to determine how + to run the tests. This file is just Python code and thus is very flexible, 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 + directory of tests, just copy lit.local.cfg from another directory to + get running. The standard lit.local.cfg simply specifies which files + to look in for tests. Any directory that contains only directories does not + need the lit.local.cfg file. Read the + Lit documentation for more + information.

+ +

The llvm-runtests function looks at each file that is passed to + it and gathers any lines together that match "RUN:". These 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 @@ -529,7 +473,7 @@ negatives).

llc, then pipe the output of llc into FileCheck. This means that FileCheck will be verifying its standard input (the llc output) against the filename argument specified (the original .ll file specified by "%s"). To see how this works, -lets look at the rest of the .ll file (after the RUN line):

+let's look at the rest of the .ll file (after the RUN line):

@@ -682,6 +626,8 @@ define i8 @coerce_offset0(i32 %V, i32* %P) {
 
 
 
+
+
 The CHECK: and CHECK-NOT: directives both take a pattern to match.  For most
 uses of FileCheck, fixed string matching is perfectly sufficient.  For some
 things, a more flexible form of matching is desired.  To support this, FileCheck
@@ -706,6 +652,8 @@ braces like you would in C.  In the rare case that you want to match double
 braces explicitly from the input, you can use something ugly like
 {{[{][{]}} as your pattern.
 
+
+
 
 
 
@@ -715,6 +663,9 @@ braces explicitly from the input, you can use something ugly like
 
 
 
+
+
+
 It is often useful to match a pattern and then verify that it occurs again
 later in the file.  For codegen tests, this can be useful to allow any register,
 but verify that that register is used consistently later.  To do this, FileCheck
@@ -746,6 +697,8 @@ that FileCheck is not actually line-oriented when it matches, this allows you to
 define two separate CHECK lines that match on the same line.
 
 
+
+

@@ -798,37 +751,10 @@ define two separate CHECK lines that match on the same line. 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".

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

- -

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.

@@ -872,14 +798,15 @@ define two separate CHECK lines that match on the same line.

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 the testing tool. 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 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: *. Here is an example of an XFAIL line:

+ if the test fails. Such test cases are counted separately by the testing + tool. To specify an expected fail, use the XFAIL keyword in the comments of + the test program followed by a colon and one or more failure patterns. Each + failure pattern can be either '*' (to specify fail everywhere), or a part of a + target triple (indicating the test should fail on that platform), or the name + of a configurable feature (for example, "loadable_module"). 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: *. Here is an + example of an XFAIL line:

@@ -906,30 +833,15 @@ define two separate CHECK lines that match on the same line.

Test suite Structure

`test-suite` Overview

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 test-suite 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.

The test-suite module contains a number of programs that can be +compiled and executed. The test-suite includes reference outputs for +all of the programs, so that the output of the executed program can be checked +for correctness.

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

@@ -951,248 +863,40 @@ go here.

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 test-suite -configure script.

+how to properly compile these programs from somewhere else. When +using LNT, use the --test-externals option to include these +tests in the results.

- -

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 the -regression tests, 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.

Running the test suite

`test-suite` Quickstart

The modern way of running the test-suite is focused on testing and +benchmarking complete compilers using +the LNT testing infrastructure.

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:

- -

cd into the llvm/projects directory in your source tree. -
Check out the test-suite module with:
- -
-
```
-% svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite
-
```
+
For more information on using LNT to execute the test-suite, please +see the LNT Quickstart +documentation.
-
This will get the test suite into llvm/projects/test-suite.
-
Configure and build llvm.
Configure and build llvm-gcc.
Install llvm-gcc somewhere.
Re-configure llvm from the top level of - each build tree (LLVM object directory tree) in which you want - to run the test suite, just as you do before building LLVM.
-
During the re-configuration, you must either: (1) - have llvm-gcc you just built in your path, or (2) - specify the directory where your just-built llvm-gcc is - installed using --with-llvmgccdir=$LLVM_GCC_DIR.
-
You must also tell the configure machinery that the test suite - is available so it can be configured for your build tree:
-
-
```
-% cd $LLVM_OBJ_ROOT ; $LLVM_SRC_ROOT/configure [--with-llvmgccdir=$LLVM_GCC_DIR]
-
```
-
-
[Remember that $LLVM_GCC_DIR is the directory where you - installed llvm-gcc, not its src or obj directory.]
-
You can now run the test suite from your build tree as follows:
-
-
```
-% cd $LLVM_OBJ_ROOT/projects/test-suite
-% make
-
```
-
-

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).

- - -

- Configuring External Tests -

- - -

In order to run the External tests in the test-suite - module, you must specify --with-externals. This - must be done during the re-configuration step (see above), - and the llvm re-configuration must recognize the - previously-built llvm-gcc. If any of these is missing or - neglected, the External tests won't work.

--with-externals
--with-externals=<directory>

- This tells LLVM where to find any external tests. They are expected to be - in specifically named subdirectories of <directory>. - If directory is left unspecified, - configure uses the default value - /home/vadve/shared/benchmarks/speccpu2000/benchspec. - Subdirectory names known to LLVM include: -

spec95
speccpu2000
speccpu2006
povray31

- Others are added from time to time, and can be determined from - configure. -

- - -

- Running different tests -

- -

In addition to the regular "whole program" tests, the test-suite -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.

- - -

- Generating test output -

- -

There are a number of ways to run the tests and generate output. The most - simple one is simply running gmake with no arguments. This will - compile and run all programs in the tree using a number of different methods - and compare results. Any failures are reported in the output, but are likely - drowned in the other output. Passes are not reported explicitely.

- -

Somewhat better is running gmake TEST=sometest test, which runs - the specified test and usually adds per-program summaries to the output - (depending on which sometest you use). For example, the nightly test - explicitely outputs TEST-PASS or TEST-FAIL for every test after each program. - Though these lines are still drowned in the output, it's easy to grep the - output logs in the Output directories.

- -

Even better are the report and report.format targets - (where format is one of html, csv, text or - graphs). The exact contents of the report are dependent on which - TEST you are running, but the text results are always shown at the - end of the run and the results are always stored in the - report.<type>.format file (when running with - TEST=<type>). - - The report also generate a file called - report.<type>.raw.out containing the output of the entire test - run. -

- - -

- Writing custom tests for the test suite -

- + +

`test-suite` Makefiles

- -

Assuming you can run the test suite, (e.g. "gmake TEST=nightly report" -should work), it is really easy to run optimizations or code generator -components against every program in the tree, collecting statistics or running -custom checks for correctness. At base, this is how the nightly tester works, -it's just one example of a general framework.

- -

Lets say that you have an LLVM optimization pass, and you want to see how -many times it triggers. First thing you should do is add an LLVM -statistic to your pass, which -will tally counts of things you care about.

- -

Following this, you can set up a test and a report that collects these and -formats them for easy viewing. This consists of two files, a -"test-suite/TEST.XXX.Makefile" fragment (where XXX is the name of your -test) and a "test-suite/TEST.XXX.report" file that indicates how to -format the output into a table. There are many example reports of various -levels of sophistication included with the test suite, and the framework is very -general.

- -

If you are interested in testing an optimization pass, check out the -"libcalls" test as an example. It can be run like this:

- -

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

- -

This will do a bunch of stuff, then eventually print a table like this:

- -

-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    | *     | 
-...
-

- -

This basically is grepping the -stats output and displaying it in a table. -You can also use the "TEST=libcalls report.html" target to get the table in HTML -form, similarly for report.csv and report.tex.

- -

The source for this is in test-suite/TEST.libcalls.*. The format is pretty -simple: the Makefile indicates how to run the test (in this case, -"opt -simplify-libcalls -stats"), and the report contains one line for -each column of the output. The first value is the header for the column and the -second is the regex to grep the output of the command for. There are lots of -example reports that can do fancy stuff.

- -

- +

Historically, the test-suite was executed using a complicated setup +of Makefiles. The LNT based approach above is recommended for most users, but +there are some testing scenarios which are not supported by the LNT approach. In +addition, LNT currently uses the Makefile setup under the covers and so +developers who are interested in how LNT works under the hood may want to +understand the Makefile based setup.

+ +

For more information on the test-suite Makefile setup, please see +the Test Suite Makefile Guide.