LLVM Testing Infrastructure Guide
=================================
-Written by John T. Criswell, Daniel Dunbar, Reid Spencer, and Tanya
-Lattner
-
.. contents::
:local:
Requirements
============
-In order to use the LLVM testing infrastructure, you will need all of
-the software required to build LLVM, as well as
-`Python <http://python.org>`_ 2.4 or later.
+In order to use the LLVM testing infrastructure, you will need all of the
+software required to build LLVM, as well as `Python <http://python.org>`_ 2.7 or
+later.
LLVM testing infrastructure organization
========================================
----------------
The regression tests 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 (and the appropriate
-``--with-llvmgcc`` options were used at ``configure`` time of the
-``llvm`` module). These tests are driven by the 'lit' testing tool,
-which is part of LLVM.
-
-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.
+feature of LLVM or trigger a specific bug in LLVM. The language they are
+written in depends on the part of LLVM being tested. These tests are driven by
+the :doc:`Lit <CommandGuide/lit>` testing tool (which is part of LLVM), and
+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.
+somewhere underneath this directory. For example, it can be a small
+piece of LLVM IR distilled from an actual application or benchmark.
``test-suite``
--------------
The tests are located in two separate Subversion modules. The
regressions tests are in the main "llvm" module under the directory
-``llvm/test`` (so you get these tests for free with the main llvm tree).
-Use "make check-all" to run the regression tests after building LLVM.
+``llvm/test`` (so you get these tests for free with the main LLVM tree).
+Use ``make check-all`` to run the regression tests after building LLVM.
The more comprehensive test suite that includes whole programs in C and C++
is in the ``test-suite`` module. See :ref:`test-suite Quickstart
Regression tests
----------------
-To run all of the LLVM regression tests, use master Makefile in the
-``llvm/test`` directory:
+To run all of the LLVM regression tests, use the master Makefile in the
+``llvm/test`` directory. LLVM Makefiles require GNU Make (read the :doc:`LLVM
+Makefile Guide <MakefileGuide>` for more details):
.. code-block:: bash
- % gmake -C llvm/test
+ % make -C llvm/test
-or
+or:
.. code-block:: bash
- % gmake check
+ % make check
If you have `Clang <http://clang.llvm.org/>`_ checked out and built, you
can run the LLVM and Clang tests simultaneously using:
-or
-
.. code-block:: bash
- % gmake check-all
+ % make check-all
-To run the tests with Valgrind (Memcheck by default), just append
-``VG=1`` to the commands above, e.g.:
+To run the tests with Valgrind (Memcheck by default), use the ``LIT_ARGS`` make
+variable to pass the required options to lit. For example, you can use:
.. code-block:: bash
- % gmake check VG=1
+ % make check LIT_ARGS="-v --vg --vg-leak"
+
+to enable testing with valgrind and with leak checking enabled.
-To run individual tests or subsets of tests, you can use the 'llvm-lit'
+To run individual tests or subsets of tests, you can use the ``llvm-lit``
script which is built as part of LLVM. For example, to run the
-'Integer/BitPacked.ll' test by itself you can run:
+``Integer/BitPacked.ll`` test by itself you can run:
.. code-block:: bash
% llvm-lit ~/llvm/test/CodeGen/ARM
-For more information on using the 'lit' tool, see 'llvm-lit --help' or
-the 'lit' man page.
+For more information on using the :program:`lit` tool, see ``llvm-lit --help``
+or the :doc:`lit man page <CommandGuide/lit>`.
Debugging Information tests
---------------------------
Regression test structure
=========================
-The LLVM regression tests are driven by 'lit' and are located in the
+The LLVM regression tests are driven by :program:`lit` 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.
+particular area of LLVM.
Writing new regression tests
----------------------------
The regression test structure is very simple, but does require some
information to be set. This information is gathered via ``configure``
-and is written to a file, ``lit.site.cfg`` in ``llvm/test``. The
-``llvm/test`` Makefile does this work for you.
+and is written to a file, ``test/lit.site.cfg`` in the build directory.
+The ``llvm/test`` Makefile does this work for you.
In order for the regression tests to work, each directory of tests must
-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
+have a ``lit.local.cfg`` file. :program:`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 ``lit.local.cfg`` from
another directory to get running. The standard ``lit.local.cfg`` simply
only directories does not need the ``lit.local.cfg`` file. Read the :doc:`Lit
documentation <CommandGuide/lit>` 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
-fail.
+Each test file must contain lines starting with "RUN:" that tell :program:`lit`
+how to run it. If there are no RUN lines, :program:`lit` will issue an error
+while running a test.
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.
-
-lit performs substitution on each RUN line to replace LLVM tool names
+to execute. Together, these lines form the "script" that :program:`lit`
+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 by :program:`lit`.
+Consequently, the syntax differs from shell in a few ways. You can specify
+as many RUN lines as needed.
+
+:program:`lit` performs substitution on each RUN line to replace LLVM tool names
with the full paths to the executable built for each tool (in
-$(LLVM\_OBJ\_ROOT)/$(BuildMode)/bin). This ensures that lit does not
-invoke any stray LLVM tools in the user's path during testing.
+``$(LLVM_OBJ_ROOT)/$(BuildMode)/bin)``. This ensures that :program:`lit` does
+not invoke any stray LLVM tools in the user's path during testing.
Each RUN line is executed on its own, distinct from other lines unless
its last character is ``\``. This continuation character causes the RUN
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
+execution. :program:`lit` 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-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 <http://www.tcl.tk/man/tcl8.5/TclCmd/exec.htm#M2>`_ command and the
-`tutorial <http://www.tcl.tk/man/tcl8.5/tutorial/Tcl26.html>`_. 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.
+As with a Unix shell, the RUN lines permit pipelines and I/O
+redirection to be used.
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 quote characters so they will get passed to the invoked program.
-For example:
+your RUN lines. In general nothing needs to be quoted. :program:`lit` won't
+strip off any quote characters so they will get passed to the invoked program.
+To avoid this use curly braces to tell :program:`lit` that it should treat
+everything enclosed as one value.
-.. code-block:: bash
+In general, you should strive to keep your RUN lines as simple as possible,
+using them only to run tools that generate textual output you can then examine.
+The recommended way to examine output to figure out if the test passes is using
+the :doc:`FileCheck tool <CommandGuide/FileCheck>`. *[The usage of grep in RUN
+lines is deprecated - please do not send or commit patches that use it.]*
- ... | grep 'find this string'
+Put related tests into a single file rather than having a separate file per
+test. Check if there are files already covering your feature and consider
+adding your code there instead of creating a new file.
-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:
+Extra files
+-----------
-.. code-block:: bash
+If your test requires extra files besides the file containing the ``RUN:``
+lines, the idiomatic place to put them is in a subdirectory ``Inputs``.
+You can then refer to the extra files as ``%S/Inputs/foo.bar``.
- ... | grep {find this string}
+For example, consider ``test/Linker/ident.ll``. The directory structure is
+as follows::
-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:
+ test/
+ Linker/
+ ident.ll
+ Inputs/
+ ident.a.ll
+ ident.b.ll
-.. code-block:: bash
+For convenience, these are the contents:
- ... | grep bb[2-8]
+.. code-block:: llvm
-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:
+ ;;;;; ident.ll:
-.. code-block:: bash
+ ; RUN: llvm-link %S/Inputs/ident.a.ll %S/Inputs/ident.b.ll -S | FileCheck %s
- ... | grep {bb\[2-8\]}
+ ; Verify that multiple input llvm.ident metadata are linked together.
-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:
+ ; CHECK-DAG: !llvm.ident = !{!0, !1, !2}
+ ; CHECK-DAG: "Compiler V1"
+ ; CHECK-DAG: "Compiler V2"
+ ; CHECK-DAG: "Compiler V3"
-.. code-block:: bash
+ ;;;;; Inputs/ident.a.ll:
- ... | grep 'i32\*'
+ !llvm.ident = !{!0, !1}
+ !0 = metadata !{metadata !"Compiler V1"}
+ !1 = metadata !{metadata !"Compiler V2"}
-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:
+ ;;;;; Inputs/ident.b.ll:
-.. code-block:: bash
+ !llvm.ident = !{!0}
+ !0 = metadata !{metadata !"Compiler V3"}
- ... | grep {i32\\*}
+For symmetry reasons, ``ident.ll`` is just a dummy file that doesn't
+actually participate in the test besides holding the ``RUN:`` lines.
-If your system includes GNU ``grep``, make sure that ``GREP_OPTIONS`` is
-not set in your environment. Otherwise, you may get invalid results
-(both false positives and false negatives).
+.. note::
-The FileCheck utility
----------------------
+ Some existing tests use ``RUN: true`` in extra files instead of just
+ putting the extra files in an ``Inputs/`` directory. This pattern is
+ deprecated.
-A powerful feature of the RUN: lines is that it allows any arbitrary
-commands to be executed as part of the test harness. While standard
-(portable) unix tools like 'grep' work fine on run lines, as you see
-above, there are a lot of caveats due to interaction with Tcl syntax,
-and we want to make sure the run lines are portable to a wide range of
-systems. Another major problem is that grep is not very good at checking
-to verify that the output of a tools contains a series of different
-output in a specific order. The FileCheck tool was designed to help with
-these problems.
+Fragile tests
+-------------
-FileCheck is designed to read a file to check from standard input, and the set
-of things to verify from a file specified as a command line argument.
-FileCheck is described in :doc:`the FileCheck man page
-<CommandGuide/FileCheck>`.
+It is easy to write a fragile test that would fail spuriously if the tool being
+tested outputs a full path to the input file. For example, :program:`opt` by
+default outputs a ``ModuleID``:
-Variables and substitutions
----------------------------
+.. code-block:: console
-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.
+ $ cat example.ll
+ define i32 @main() nounwind {
+ ret i32 0
+ }
-Here are the available variable names. The alternate syntax is listed in
-parentheses.
+ $ opt -S /path/to/example.ll
+ ; ModuleID = '/path/to/example.ll'
-``$test`` (``%s``)
- The full path to the test case's source. This is suitable for passing on
- the command line as the input to an llvm tool.
+ define i32 @main() nounwind {
+ ret i32 0
+ }
-``%(line)``, ``%(line+<number>)``, ``%(line-<number>)``
- The number of the line where this variable is used, with an optional
- integer offset. This can be used in tests with multiple RUN: lines,
- which reference test file's line numbers.
+``ModuleID`` can unexpetedly match against ``CHECK`` lines. For example:
+
+.. code-block:: llvm
+
+ ; RUN: opt -S %s | FileCheck
-``$srcdir``
- The source directory from where the "``make check``" was run.
+ define i32 @main() nounwind {
+ ; CHECK-NOT: load
+ ret i32 0
+ }
-``objdir``
- The object directory that corresponds to the ``$srcdir``.
+This test will fail if placed into a ``download`` directory.
+
+To make your tests robust, always use ``opt ... < %s`` in the RUN line.
+:program:`opt` does not output a ``ModuleID`` when input comes from stdin.
+
+Platform-Specific Tests
+-----------------------
+
+Whenever adding tests that require the knowledge of a specific platform,
+either related to code generated, specific output or back-end features,
+you must make sure to isolate the features, so that buildbots that
+run on different architectures (and don't even compile all back-ends),
+don't fail.
+
+The first problem is to check for target-specific output, for example sizes
+of structures, paths and architecture names, for example:
+
+* Tests containing Windows paths will fail on Linux and vice-versa.
+* Tests that check for ``x86_64`` somewhere in the text will fail anywhere else.
+* Tests where the debug information calculates the size of types and structures.
+
+Also, if the test rely on any behaviour that is coded in any back-end, it must
+go in its own directory. So, for instance, code generator tests for ARM go
+into ``test/CodeGen/ARM`` and so on. Those directories contain a special
+``lit`` configuration file that ensure all tests in that directory will
+only run if a specific back-end is compiled and available.
+
+For instance, on ``test/CodeGen/ARM``, the ``lit.local.cfg`` is:
+
+.. code-block:: python
+
+ config.suffixes = ['.ll', '.c', '.cpp', '.test']
+ if not 'ARM' in config.root.targets:
+ config.unsupported = True
+
+Other platform-specific tests are those that depend on a specific feature
+of a specific sub-architecture, for example only to Intel chips that support ``AVX2``.
+
+For instance, ``test/CodeGen/X86/psubus.ll`` tests three sub-architecture
+variants:
+
+.. code-block:: llvm
+
+ ; RUN: llc -mcpu=core2 < %s | FileCheck %s -check-prefix=SSE2
+ ; RUN: llc -mcpu=corei7-avx < %s | FileCheck %s -check-prefix=AVX1
+ ; RUN: llc -mcpu=core-avx2 < %s | FileCheck %s -check-prefix=AVX2
+
+And the checks are different:
+
+.. code-block:: llvm
-``subdir``
- A partial path from the ``test`` directory that contains the
- sub-directory that contains the test source being executed.
+ ; SSE2: @test1
+ ; SSE2: psubusw LCPI0_0(%rip), %xmm0
+ ; AVX1: @test1
+ ; AVX1: vpsubusw LCPI0_0(%rip), %xmm0, %xmm0
+ ; AVX2: @test1
+ ; AVX2: vpsubusw LCPI0_0(%rip), %xmm0, %xmm0
-``srcroot``
- The root directory of the LLVM src tree.
+So, if you're testing for a behaviour that you know is platform-specific or
+depends on special features of sub-architectures, you must add the specific
+triple, test with the specific FileCheck and put it into the specific
+directory that will filter out all other architectures.
-``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.
+Substitutions
+-------------
-``tmp``
- The path to a temporary file name that could be used for this test case.
+Besides replacing LLVM tool names the following substitutions are performed in
+RUN lines:
+
+``%%``
+ Replaced by a single ``%``. This allows escaping other substitutions.
+
+``%s``
+ File path to the test case's source. This is suitable for passing on the
+ command line as the input to an LLVM tool.
+
+ Example: ``/home/user/llvm/test/MC/ELF/foo_test.s``
+
+``%S``
+ Directory path to the test case's source.
+
+ Example: ``/home/user/llvm/test/MC/ELF``
+
+``%t``
+ File 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.
-``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".
+ Example: ``/home/user/llvm.build/test/MC/ELF/Output/foo_test.s.tmp``
+
+``%T``
+ Directory of ``%t``.
+
+ Example: ``/home/user/llvm.build/test/MC/ELF/Output``
+
+``%{pathsep}``
-``link`` (``%link``)
- This full link command used to link LLVM executables. This has all the
- configured -I, -L and -l options.
+ Expands to the path separator, i.e. ``:`` (or ``;`` on Windows).
+
+
+**LLVM-specific substitutions:**
+
+``%shlibext``
+ The suffix for the host platforms shared library files. This includes the
+ period as the first character.
+
+ Example: ``.so`` (Linux), ``.dylib`` (OS X), ``.dll`` (Windows)
+
+``%exeext``
+ The suffix for the host platforms executable files. This includes the
+ period as the first character.
+
+ Example: ``.exe`` (Windows), empty on Linux.
+
+``%(line)``, ``%(line+<number>)``, ``%(line-<number>)``
+ The number of the line where this substitution is used, with an optional
+ integer offset. This can be used in tests with multiple RUN lines, which
+ reference test file's line numbers.
-``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.
+**Clang-specific substitutions:**
+
+``%clang``
+ Invokes the Clang driver.
+
+``%clang_cpp``
+ Invokes the Clang driver for C++.
+
+``%clang_cl``
+ Invokes the CL-compatible Clang driver.
+
+``%clangxx``
+ Invokes the G++-compatible Clang driver.
+
+``%clang_cc1``
+ Invokes the Clang frontend.
+
+``%itanium_abi_triple``, ``%ms_abi_triple``
+ These substitutions can be used to get the current target triple adjusted to
+ the desired ABI. For example, if the test suite is running with the
+ ``i686-pc-win32`` target, ``%itanium_abi_triple`` will expand to
+ ``i686-pc-mingw32``. This allows a test to run with a specific ABI without
+ constraining it to a specific triple.
+
+To add more substituations, look at ``test/lit.cfg`` or ``lit.local.cfg``.
+
+
+Options
+-------
+
+The llvm lit configuration allows to customize some things with user options:
+
+``llc``, ``opt``, ...
+ Substitute the respective llvm tool name with a custom command line. This
+ allows to specify custom paths and default arguments for these tools.
+ Example:
+
+ % llvm-lit "-Dllc=llc -verify-machineinstrs"
+
+``run_long_tests``
+ Enable the execution of long running tests.
+
+``llvm_site_config``
+ Load the specified lit configuration instead of the default one.
+
Other Features
--------------
-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
+To make RUN line writing easier, there are several helper programs. These
+helpers are in the PATH when running tests, so you can just call them using
+their name. For example:
+
``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.
+ This program runs its arguments and then inverts the result code from it.
+ Zero result codes become 1. Non-zero result codes become 0.
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:``
; XFAIL: darwin,sun
-To make the output more useful, the ``llvm_runtest`` function wil scan
+To make the output more useful, :program:`lit` will 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
projects / oota-llvm.git / blobdiff