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+==============================
+LLVM test-suite Makefile Guide
+==============================
+
+Written by John T. Criswell, Daniel Dunbar, Reid Spencer, and Tanya
+Lattner
+
+.. contents::
+   :local:
+
+Overview
+========
+
+This document describes the features of the Makefile-based LLVM
+test-suite. This way of interacting with the test-suite is deprecated in
+favor of running the test-suite using LNT, but may continue to prove
+useful for some users. See the Testing Guide's :ref:`test-suite Quickstart
+<test-suite-quickstart>` section for more information.
+
+Test suite Structure
+====================
+
+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.
+
+``test-suite`` tests are divided into three types of tests: MultiSource,
+SingleSource, and External.
+
+-  ``test-suite/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.
+
+-  ``test-suite/MultiSource``
+
+   The MultiSource directory contains subdirectories which contain
+   entire programs with multiple source files. Large benchmarks and
+   whole applications go here.
+
+-  ``test-suite/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 test-suite ``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 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
+======================
+
+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:
+
+   .. code-block:: bash
+
+       % svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite
+
+   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:
+
+   .. code-block:: bash
+
+       % 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:
+
+   .. code-block:: bash
+
+       % 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
+explicitly.
+
+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
+explicitly 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
+---------------------------------------
+
+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 <ProgrammersManual.html#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:
+
+.. code-block:: bash
+
+    % 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.