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
========================================
% 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
- % make 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``
script which is built as part of LLVM. For example, to run the
; 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. In general, it's useful to read the code of other tests to figure out
-what you can use in yours. The major differences are:
-
-- You can't do ``2>&1``. That will cause :program:`lit` to write to a file
- named ``&1``. Usually this is done to get stderr to go through a pipe. You
- can do that 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.
+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. :program:`lit` won't
strip off any quote characters so they will get passed to the invoked program.
-For example:
+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
-make ``grep`` to look for ``'find`` in the files ``this`` and
-``string'``. To avoid this use curly braces to tell :program:`lit` 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::
-In general, you should strive to keep your RUN lines as simple as possible,
-using them only to run tools that generate the output you can then examine. The
-recommended way to examine output to figure out if the test passes it using the
-:doc:`FileCheck tool <CommandGuide/FileCheck>`. The usage of ``grep`` in RUN
-lines is discouraged.
-
-The FileCheck utility
----------------------
-
-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 shell 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 :program:`FileCheck` tool was designed to
-help with these problems.
-
-:program:`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. :program:`FileCheck` is described in :doc:`the FileCheck man page
-<CommandGuide/FileCheck>`.
-
-Variables and substitutions
----------------------------
+ test/
+ Linker/
+ ident.ll
+ Inputs/
+ ident.a.ll
+ ident.b.ll
-With a RUN line there are a number of substitutions that are permitted.
-To make a substitution just write the variable's name preceded by a ``$``.
-Additionally, for compatibility reasons with previous versions of the
-test library, certain names can be accessed with an alternate syntax: a
-% prefix. These alternates are deprecated and may go away in a future
-version.
+For convenience, these are the contents:
-Here are the available variable names. The alternate syntax is listed in
-parentheses.
+.. code-block:: llvm
-``$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.
+ ;;;;; ident.ll:
-``%(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.
+ ; RUN: llvm-link %S/Inputs/ident.a.ll %S/Inputs/ident.b.ll -S | FileCheck %s
+
+ ; Verify that multiple input llvm.ident metadata are linked together.
+
+ ; CHECK-DAG: !llvm.ident = !{!0, !1, !2}
+ ; CHECK-DAG: "Compiler V1"
+ ; CHECK-DAG: "Compiler V2"
+ ; CHECK-DAG: "Compiler V3"
+
+ ;;;;; Inputs/ident.a.ll:
+
+ !llvm.ident = !{!0, !1}
+ !0 = metadata !{metadata !"Compiler V1"}
+ !1 = metadata !{metadata !"Compiler V2"}
+
+ ;;;;; Inputs/ident.b.ll:
+
+ !llvm.ident = !{!0}
+ !0 = metadata !{metadata !"Compiler V3"}
+
+For symmetry reasons, ``ident.ll`` is just a dummy file that doesn't
+actually participate in the test besides holding the ``RUN:`` lines.
+
+.. note::
+
+ Some existing tests use ``RUN: true`` in extra files instead of just
+ putting the extra files in an ``Inputs/`` directory. This pattern is
+ deprecated.
+
+Fragile tests
+-------------
-``$srcdir``
- The source directory from where the ``make check`` was run.
+It is easy to write a fragile test that would fail spuriously if the tool being
+tested outputs a full path to the input file. For example, :program:`opt` by
+default outputs a ``ModuleID``:
-``objdir``
- The object directory that corresponds to the ``$srcdir``.
+.. code-block:: console
-``subdir``
- A partial path from the ``test`` directory that contains the
- sub-directory that contains the test source being executed.
+ $ cat example.ll
+ define i32 @main() nounwind {
+ ret i32 0
+ }
-``srcroot``
- The root directory of the LLVM src tree.
+ $ opt -S /path/to/example.ll
+ ; ModuleID = '/path/to/example.ll'
+
+ define i32 @main() nounwind {
+ ret i32 0
+ }
+
+``ModuleID`` can unexpetedly match against ``CHECK`` lines. For example:
+
+.. code-block:: llvm
+
+ ; RUN: opt -S %s | FileCheck
+
+ define i32 @main() nounwind {
+ ; CHECK-NOT: load
+ ret i32 0
+ }
+
+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
-``objroot``
- The root directory of the LLVM object tree. This could be the same as
- the srcroot.
+ ; 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
-``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.
+And the checks are different:
-``tmp``
- The path to a temporary file name that could be used for this test case.
+.. code-block:: llvm
+
+ ; 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
+
+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.
+
+
+Substitutions
+-------------
+
+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).
-``shlibext`` (``%shlibext``)
- The suffix for the host platforms shared library (DLL) files. This
- includes the period as the first character.
-To add more variables, look at ``test/lit.cfg``.
+**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.
+
+
+**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 helper scripts and programs
-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.
+ 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
projects / oota-llvm.git / blobdiff