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      1 ==============================
      2 LLVM test-suite Makefile Guide
      3 ==============================
      4 
      5 .. contents::
      6    :local:
      7 
      8 Overview
      9 ========
     10 
     11 This document describes the features of the Makefile-based LLVM
     12 test-suite. This way of interacting with the test-suite is deprecated in
     13 favor of running the test-suite using LNT, but may continue to prove
     14 useful for some users. See the Testing Guide's :ref:`test-suite Quickstart
     15 <test-suite-quickstart>` section for more information.
     16 
     17 Test suite Structure
     18 ====================
     19 
     20 The ``test-suite`` module contains a number of programs that can be
     21 compiled with LLVM and executed. These programs are compiled using the
     22 native compiler and various LLVM backends. The output from the program
     23 compiled with the native compiler is assumed correct; the results from
     24 the other programs are compared to the native program output and pass if
     25 they match.
     26 
     27 When executing tests, it is usually a good idea to start out with a
     28 subset of the available tests or programs. This makes test run times
     29 smaller at first and later on this is useful to investigate individual
     30 test failures. To run some test only on a subset of programs, simply
     31 change directory to the programs you want tested and run ``gmake``
     32 there. Alternatively, you can run a different test using the ``TEST``
     33 variable to change what tests or run on the selected programs (see below
     34 for more info).
     35 
     36 In addition for testing correctness, the ``test-suite`` directory also
     37 performs timing tests of various LLVM optimizations. It also records
     38 compilation times for the compilers and the JIT. This information can be
     39 used to compare the effectiveness of LLVM's optimizations and code
     40 generation.
     41 
     42 ``test-suite`` tests are divided into three types of tests: MultiSource,
     43 SingleSource, and External.
     44 
     45 -  ``test-suite/SingleSource``
     46 
     47    The SingleSource directory contains test programs that are only a
     48    single source file in size. These are usually small benchmark
     49    programs or small programs that calculate a particular value. Several
     50    such programs are grouped together in each directory.
     51 
     52 -  ``test-suite/MultiSource``
     53 
     54    The MultiSource directory contains subdirectories which contain
     55    entire programs with multiple source files. Large benchmarks and
     56    whole applications go here.
     57 
     58 -  ``test-suite/External``
     59 
     60    The External directory contains Makefiles for building code that is
     61    external to (i.e., not distributed with) LLVM. The most prominent
     62    members of this directory are the SPEC 95 and SPEC 2000 benchmark
     63    suites. The ``External`` directory does not contain these actual
     64    tests, but only the Makefiles that know how to properly compile these
     65    programs from somewhere else. The presence and location of these
     66    external programs is configured by the test-suite ``configure``
     67    script.
     68 
     69 Each tree is then subdivided into several categories, including
     70 applications, benchmarks, regression tests, code that is strange
     71 grammatically, etc. These organizations should be relatively self
     72 explanatory.
     73 
     74 Some tests are known to fail. Some are bugs that we have not fixed yet;
     75 others are features that we haven't added yet (or may never add). In the
     76 regression tests, the result for such tests will be XFAIL (eXpected
     77 FAILure). In this way, you can tell the difference between an expected
     78 and unexpected failure.
     79 
     80 The tests in the test suite have no such feature at this time. If the
     81 test passes, only warnings and other miscellaneous output will be
     82 generated. If a test fails, a large <program> FAILED message will be
     83 displayed. This will help you separate benign warnings from actual test
     84 failures.
     85 
     86 Running the test suite
     87 ======================
     88 
     89 First, all tests are executed within the LLVM object directory tree.
     90 They *are not* executed inside of the LLVM source tree. This is because
     91 the test suite creates temporary files during execution.
     92 
     93 To run the test suite, you need to use the following steps:
     94 
     95 #. ``cd`` into the ``llvm/projects`` directory in your source tree.
     96 #. Check out the ``test-suite`` module with:
     97 
     98    .. code-block:: bash
     99 
    100        % svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite
    101 
    102    This will get the test suite into ``llvm/projects/test-suite``.
    103 
    104 #. Configure and build ``llvm``.
    105 
    106 #. Configure and build ``llvm-gcc``.
    107 
    108 #. Install ``llvm-gcc`` somewhere.
    109 
    110 #. *Re-configure* ``llvm`` from the top level of each build tree (LLVM
    111    object directory tree) in which you want to run the test suite, just
    112    as you do before building LLVM.
    113 
    114    During the *re-configuration*, you must either: (1) have ``llvm-gcc``
    115    you just built in your path, or (2) specify the directory where your
    116    just-built ``llvm-gcc`` is installed using
    117    ``--with-llvmgccdir=$LLVM_GCC_DIR``.
    118 
    119    You must also tell the configure machinery that the test suite is
    120    available so it can be configured for your build tree:
    121 
    122    .. code-block:: bash
    123 
    124        % cd $LLVM_OBJ_ROOT ; $LLVM_SRC_ROOT/configure [--with-llvmgccdir=$LLVM_GCC_DIR]
    125 
    126    [Remember that ``$LLVM_GCC_DIR`` is the directory where you
    127    *installed* llvm-gcc, not its src or obj directory.]
    128 
    129 #. You can now run the test suite from your build tree as follows:
    130 
    131    .. code-block:: bash
    132 
    133        % cd $LLVM_OBJ_ROOT/projects/test-suite
    134        % make
    135 
    136 Note that the second and third steps only need to be done once. After
    137 you have the suite checked out and configured, you don't need to do it
    138 again (unless the test code or configure script changes).
    139 
    140 Configuring External Tests
    141 --------------------------
    142 
    143 In order to run the External tests in the ``test-suite`` module, you
    144 must specify *--with-externals*. This must be done during the
    145 *re-configuration* step (see above), and the ``llvm`` re-configuration
    146 must recognize the previously-built ``llvm-gcc``. If any of these is
    147 missing or neglected, the External tests won't work.
    148 
    149 * *--with-externals*
    150 
    151 * *--with-externals=<directory>*
    152 
    153 This tells LLVM where to find any external tests. They are expected to
    154 be in specifically named subdirectories of <``directory``>. If
    155 ``directory`` is left unspecified, ``configure`` uses the default value
    156 ``/home/vadve/shared/benchmarks/speccpu2000/benchspec``. Subdirectory
    157 names known to LLVM include:
    158 
    159 * spec95
    160 
    161 * speccpu2000
    162 
    163 * speccpu2006
    164 
    165 * povray31
    166 
    167 Others are added from time to time, and can be determined from
    168 ``configure``.
    169 
    170 Running different tests
    171 -----------------------
    172 
    173 In addition to the regular "whole program" tests, the ``test-suite``
    174 module also provides a mechanism for compiling the programs in different
    175 ways. If the variable TEST is defined on the ``gmake`` command line, the
    176 test system will include a Makefile named
    177 ``TEST.<value of TEST variable>.Makefile``. This Makefile can modify
    178 build rules to yield different results.
    179 
    180 For example, the LLVM nightly tester uses ``TEST.nightly.Makefile`` to
    181 create the nightly test reports. To run the nightly tests, run
    182 ``gmake TEST=nightly``.
    183 
    184 There are several TEST Makefiles available in the tree. Some of them are
    185 designed for internal LLVM research and will not work outside of the
    186 LLVM research group. They may still be valuable, however, as a guide to
    187 writing your own TEST Makefile for any optimization or analysis passes
    188 that you develop with LLVM.
    189 
    190 Generating test output
    191 ----------------------
    192 
    193 There are a number of ways to run the tests and generate output. The
    194 most simple one is simply running ``gmake`` with no arguments. This will
    195 compile and run all programs in the tree using a number of different
    196 methods and compare results. Any failures are reported in the output,
    197 but are likely drowned in the other output. Passes are not reported
    198 explicitly.
    199 
    200 Somewhat better is running ``gmake TEST=sometest test``, which runs the
    201 specified test and usually adds per-program summaries to the output
    202 (depending on which sometest you use). For example, the ``nightly`` test
    203 explicitly outputs TEST-PASS or TEST-FAIL for every test after each
    204 program. Though these lines are still drowned in the output, it's easy
    205 to grep the output logs in the Output directories.
    206 
    207 Even better are the ``report`` and ``report.format`` targets (where
    208 ``format`` is one of ``html``, ``csv``, ``text`` or ``graphs``). The
    209 exact contents of the report are dependent on which ``TEST`` you are
    210 running, but the text results are always shown at the end of the run and
    211 the results are always stored in the ``report.<type>.format`` file (when
    212 running with ``TEST=<type>``). The ``report`` also generate a file
    213 called ``report.<type>.raw.out`` containing the output of the entire
    214 test run.
    215 
    216 Writing custom tests for the test suite
    217 ---------------------------------------
    218 
    219 Assuming you can run the test suite, (e.g.
    220 "``gmake TEST=nightly report``" should work), it is really easy to run
    221 optimizations or code generator components against every program in the
    222 tree, collecting statistics or running custom checks for correctness. At
    223 base, this is how the nightly tester works, it's just one example of a
    224 general framework.
    225 
    226 Lets say that you have an LLVM optimization pass, and you want to see
    227 how many times it triggers. First thing you should do is add an LLVM
    228 `statistic <ProgrammersManual.html#Statistic>`_ to your pass, which will
    229 tally counts of things you care about.
    230 
    231 Following this, you can set up a test and a report that collects these
    232 and formats them for easy viewing. This consists of two files, a
    233 "``test-suite/TEST.XXX.Makefile``" fragment (where XXX is the name of
    234 your test) and a "``test-suite/TEST.XXX.report``" file that indicates
    235 how to format the output into a table. There are many example reports of
    236 various levels of sophistication included with the test suite, and the
    237 framework is very general.
    238 
    239 If you are interested in testing an optimization pass, check out the
    240 "libcalls" test as an example. It can be run like this:
    241 
    242 .. code-block:: bash
    243 
    244     % cd llvm/projects/test-suite/MultiSource/Benchmarks  # or some other level
    245     % make TEST=libcalls report
    246 
    247 This will do a bunch of stuff, then eventually print a table like this:
    248 
    249 ::
    250 
    251     Name                                  | total | #exit |
    252     ...
    253     FreeBench/analyzer/analyzer           | 51    | 6     |
    254     FreeBench/fourinarow/fourinarow       | 1     | 1     |
    255     FreeBench/neural/neural               | 19    | 9     |
    256     FreeBench/pifft/pifft                 | 5     | 3     |
    257     MallocBench/cfrac/cfrac               | 1     | *     |
    258     MallocBench/espresso/espresso         | 52    | 12    |
    259     MallocBench/gs/gs                     | 4     | *     |
    260     Prolangs-C/TimberWolfMC/timberwolfmc  | 302   | *     |
    261     Prolangs-C/agrep/agrep                | 33    | 12    |
    262     Prolangs-C/allroots/allroots          | *     | *     |
    263     Prolangs-C/assembler/assembler        | 47    | *     |
    264     Prolangs-C/bison/mybison              | 74    | *     |
    265     ...
    266 
    267 This basically is grepping the -stats output and displaying it in a
    268 table. You can also use the "TEST=libcalls report.html" target to get
    269 the table in HTML form, similarly for report.csv and report.tex.
    270 
    271 The source for this is in ``test-suite/TEST.libcalls.*``. The format is
    272 pretty simple: the Makefile indicates how to run the test (in this case,
    273 "``opt -simplify-libcalls -stats``"), and the report contains one line
    274 for each column of the output. The first value is the header for the
    275 column and the second is the regex to grep the output of the command
    276 for. There are lots of example reports that can do fancy stuff.
    277