1test-suite Guide
2================
3
4Quickstart
5----------
6
71. The lit test runner is required to run the tests. You can either use one
8   from an LLVM build:
9
10   ```bash
11   % <path to llvm build>/bin/llvm-lit --version
12   lit 0.8.0dev
13   ```
14
15   An alternative is installing it as a python package in a python virtual
16   environment:
17
18   ```bash
19   % mkdir venv
20   % virtualenv venv
21   % . venv/bin/activate
22   % pip install svn+https://llvm.org/svn/llvm-project/llvm/trunk/utils/lit
23   % lit --version
24   lit 0.8.0dev
25   ```
26
272. Check out the `test-suite` module with:
28
29   ```bash
30   % git clone https://github.com/llvm/llvm-test-suite.git test-suite
31   ```
32
333. Create a build directory and use CMake to configure the suite. Use the
34   `CMAKE_C_COMPILER` option to specify the compiler to test. Use a cache file
35   to choose a typical build configuration:
36
37   ```bash
38   % mkdir test-suite-build
39   % cd test-suite-build
40   % cmake -DCMAKE_C_COMPILER=<path to llvm build>/bin/clang \
41           -C../test-suite/cmake/caches/O3.cmake \
42           ../test-suite
43   ```
44
454. Build the benchmarks:
46
47   ```text
48   % make
49   Scanning dependencies of target timeit-target
50   [  0%] Building C object tools/CMakeFiles/timeit-target.dir/timeit.c.o
51   [  0%] Linking C executable timeit-target
52   ...
53   ```
54
555. Run the tests with lit:
56
57   ```text
58   % llvm-lit -v -j 1 -o results.json .
59   -- Testing: 474 tests, 1 threads --
60   PASS: test-suite :: MultiSource/Applications/ALAC/decode/alacconvert-decode.test (1 of 474)
61   ********** TEST 'test-suite :: MultiSource/Applications/ALAC/decode/alacconvert-decode.test' RESULTS **********
62   compile_time: 0.2192
63   exec_time: 0.0462
64   hash: "59620e187c6ac38b36382685ccd2b63b"
65   size: 83348
66   **********
67   PASS: test-suite :: MultiSource/Applications/ALAC/encode/alacconvert-encode.test (2 of 474)
68   ...
69   ```
70
716. Show and compare result files (optional):
72
73   ```bash
74   # Make sure pandas and scipy are installed. Prepend `sudo` if necessary.
75   % pip install pandas scipy
76   # Show a single result file:
77   % test-suite/utils/compare.py results.json
78   # Compare two result files:
79   % test-suite/utils/compare.py results_a.json results_b.json
80   ```
81
82
83Structure
84---------
85
86The test-suite contains benchmark and test programs.  The programs come with
87reference outputs so that their correctness can be checked.  The suite comes
88with tools to collect metrics such as benchmark runtime, compilation time and
89code size.
90
91The test-suite is divided into several directories:
92
93-  `SingleSource/`
94
95   Contains test programs that are only a single source file in size.  A
96   subdirectory may contain several programs.
97
98-  `MultiSource/`
99
100   Contains subdirectories which entire programs with multiple source files.
101   Large benchmarks and whole applications go here.
102
103-  `MicroBenchmarks/`
104
105   Programs using the [google-benchmark](https://github.com/google/benchmark)
106   library. The programs define functions that are run multiple times until the
107   measurement results are statistically significant.
108
109-  `External/`
110
111   Contains descriptions and test data for code that cannot be directly
112   distributed with the test-suite. The most prominent members of this
113   directory are the SPEC CPU benchmark suites.
114   See [External Suites](#external-suites).
115
116-  `Bitcode/`
117
118   These tests are mostly written in LLVM bitcode.
119
120-  `CTMark/`
121
122   Contains symbolic links to other benchmarks forming a representative sample
123   for compilation performance measurements.
124
125### Benchmarks
126
127Every program can work as a correctness test. Some programs are unsuitable for
128performance measurements. Setting the `TEST_SUITE_BENCHMARKING_ONLY` CMake
129option to `ON` will disable them.
130
131
132Configuration
133-------------
134
135The test-suite has configuration options to customize building and running the
136benchmarks. CMake can print a list of them:
137
138```bash
139% cd test-suite-build
140# Print basic options:
141% cmake -LH
142# Print all options:
143% cmake -LAH
144```
145
146### Common Configuration Options
147
148- `CMAKE_C_FLAGS`
149
150  Specify extra flags to be passed to C compiler invocations.  The flags are
151  also passed to the C++ compiler and linker invocations.  See
152  [https://cmake.org/cmake/help/latest/variable/CMAKE_LANG_FLAGS.html](https://cmake.org/cmake/help/latest/variable/CMAKE_LANG_FLAGS.html)
153
154- `CMAKE_C_COMPILER`
155
156  Select the C compiler executable to be used. Note that the C++ compiler is
157  inferred automatically i.e. when specifying `path/to/clang` CMake will
158  automatically use `path/to/clang++` as the C++ compiler.  See
159  [https://cmake.org/cmake/help/latest/variable/CMAKE_LANG_COMPILER.html](https://cmake.org/cmake/help/latest/variable/CMAKE_LANG_COMPILER.html)
160
161- `CMAKE_Fortran_COMPILER`
162
163  Select the Fortran compiler executable to be used. Not set by default and not
164  required unless running the Fortran Test Suite.
165
166- `CMAKE_BUILD_TYPE`
167
168  Select a build type like `OPTIMIZE` or `DEBUG` selecting a set of predefined
169  compiler flags. These flags are applied regardless of the `CMAKE_C_FLAGS`
170  option and may be changed by modifying `CMAKE_C_FLAGS_OPTIMIZE` etc.  See
171  [https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html](https://cmake.org/cmake/help/latest/variable/CMAKE_BUILD_TYPE.html)
172
173- `TEST_SUITE_FORTRAN`
174
175  Activate that Fortran tests. This is a work in progress. More information can be
176  found in the [Flang documentation](https://flang.llvm.org/docs/html/FortranLLVMTestSuite.html)
177
178- `TEST_SUITE_RUN_UNDER`
179
180  Prefix test invocations with the given tool. This is typically used to run
181  cross-compiled tests within a simulator tool.
182
183- `TEST_SUITE_BENCHMARKING_ONLY`
184
185  Disable tests that are unsuitable for performance measurements. The disabled
186  tests either run for a very short time or are dominated by I/O performance
187  making them unsuitable as compiler performance tests.
188
189- `TEST_SUITE_SUBDIRS`
190
191  Semicolon-separated list of directories to include. This can be used to only
192  build parts of the test-suite or to include external suites.  This option
193  does not work reliably with deeper subdirectories as it skips intermediate
194  `CMakeLists.txt` files which may be required.
195
196- `TEST_SUITE_COLLECT_STATS`
197
198  Collect internal LLVM statistics. Appends `-save-stats=obj` when invoking the
199  compiler and makes the lit runner collect and merge the statistic files.
200
201- `TEST_SUITE_RUN_BENCHMARKS`
202
203  If this is set to `OFF` then lit will not actually run the tests but just
204  collect build statistics like compile time and code size.
205
206- `TEST_SUITE_USE_PERF`
207
208  Use the `perf` tool for time measurement instead of the `timeit` tool that
209  comes with the test-suite.  The `perf` is usually available on linux systems.
210
211- `TEST_SUITE_SPEC2000_ROOT`, `TEST_SUITE_SPEC2006_ROOT`, `TEST_SUITE_SPEC2017_ROOT`, ...
212
213  Specify installation directories of external benchmark suites. You can find
214  more information about expected versions or usage in the README files in the
215  `External` directory (such as `External/SPEC/README`)
216
217### Common CMake Flags
218
219- `-GNinja`
220
221  Generate build files for the ninja build tool.
222
223- `-Ctest-suite/cmake/caches/<cachefile.cmake>`
224
225  Use a CMake cache.  The test-suite comes with several CMake caches which
226  predefine common or tricky build configurations.
227
228
229Displaying and Analyzing Results
230--------------------------------
231
232The `compare.py` script displays and compares result files.  A result file is
233produced when invoking lit with the `-o filename.json` flag.
234
235Example usage:
236
237- Basic Usage:
238
239  ```text
240  % test-suite/utils/compare.py baseline.json
241  Warning: 'test-suite :: External/SPEC/CINT2006/403.gcc/403.gcc.test' has No metrics!
242  Tests: 508
243  Metric: exec_time
244
245  Program                                         baseline
246
247  INT2006/456.hmmer/456.hmmer                   1222.90
248  INT2006/464.h264ref/464.h264ref               928.70
249  ...
250               baseline
251  count  506.000000
252  mean   20.563098
253  std    111.423325
254  min    0.003400
255  25%    0.011200
256  50%    0.339450
257  75%    4.067200
258  max    1222.896800
259  ```
260
261- Show compile_time or text segment size metrics:
262
263  ```bash
264  % test-suite/utils/compare.py -m compile_time baseline.json
265  % test-suite/utils/compare.py -m size.__text baseline.json
266  ```
267
268- Compare two result files and filter short running tests:
269
270  ```bash
271  % test-suite/utils/compare.py --filter-short baseline.json experiment.json
272  ...
273  Program                                         baseline  experiment  diff
274
275  SingleSour.../Benchmarks/Linpack/linpack-pc     5.16      4.30        -16.5%
276  MultiSourc...erolling-dbl/LoopRerolling-dbl     7.01      7.86         12.2%
277  SingleSour...UnitTests/Vectorizer/gcc-loops     3.89      3.54        -9.0%
278  ...
279  ```
280
281- Merge multiple baseline and experiment result files by taking the minimum
282  runtime each:
283
284  ```bash
285  % test-suite/utils/compare.py base0.json base1.json base2.json vs exp0.json exp1.json exp2.json
286  ```
287
288### Continuous Tracking with LNT
289
290LNT is a set of client and server tools for continuously monitoring
291performance. You can find more information at
292[https://llvm.org/docs/lnt](https://llvm.org/docs/lnt). The official LNT instance
293of the LLVM project is hosted at [http://lnt.llvm.org](http://lnt.llvm.org).
294
295
296External Suites
297---------------
298
299External suites such as SPEC can be enabled by either
300
301- placing (or linking) them into the `test-suite/test-suite-externals/xxx` directory (example: `test-suite/test-suite-externals/speccpu2000`)
302- using a configuration option such as `-D TEST_SUITE_SPEC2000_ROOT=path/to/speccpu2000`
303
304You can find further information in the respective README files such as
305`test-suite/External/SPEC/README`.
306
307For the SPEC benchmarks you can switch between the `test`, `train` and
308`ref` input datasets via the `TEST_SUITE_RUN_TYPE` configuration option.
309The `train` dataset is used by default.
310
311
312Custom Suites
313-------------
314
315You can build custom suites using the test-suite infrastructure. A custom suite
316has a `CMakeLists.txt` file at the top directory. The `CMakeLists.txt` will be
317picked up automatically if placed into a subdirectory of the test-suite or when
318setting the `TEST_SUITE_SUBDIRS` variable:
319
320```bash
321% cmake -DTEST_SUITE_SUBDIRS=path/to/my/benchmark-suite ../test-suite
322```
323
324
325Profile Guided Optimization
326---------------------------
327
328Profile guided optimization requires to compile and run twice. First the
329benchmark should be compiled with profile generation instrumentation enabled
330and setup for training data. The lit runner will merge the profile files
331using `llvm-profdata` so they can be used by the second compilation run.
332
333Example:
334```bash
335# Profile generation run:
336% cmake -DTEST_SUITE_PROFILE_GENERATE=ON \
337        -DTEST_SUITE_RUN_TYPE=train \
338        ../test-suite
339% make
340% llvm-lit .
341# Use the profile data for compilation and actual benchmark run:
342% cmake -DTEST_SUITE_PROFILE_GENERATE=OFF \
343        -DTEST_SUITE_PROFILE_USE=ON \
344        -DTEST_SUITE_RUN_TYPE=ref \
345        .
346% make
347% llvm-lit -o result.json .
348```
349
350The `TEST_SUITE_RUN_TYPE` setting only affects the SPEC benchmark suites.
351
352
353Cross Compilation and External Devices
354--------------------------------------
355
356### Compilation
357
358CMake allows to cross compile to a different target via toolchain files. More
359information can be found here:
360
361- [https://llvm.org/docs/lnt/tests.html#cross-compiling](https://llvm.org/docs/lnt/tests.html#cross-compiling)
362
363- [https://cmake.org/cmake/help/latest/manual/cmake-toolchains.7.html](https://cmake.org/cmake/help/latest/manual/cmake-toolchains.7.html)
364
365Cross compilation from macOS to iOS is possible with the
366`test-suite/cmake/caches/target-target-*-iphoneos-internal.cmake` CMake cache
367files; this requires an internal iOS SDK.
368
369### Running
370
371There are two ways to run the tests in a cross compilation setting:
372
373- Via SSH connection to an external device: The `TEST_SUITE_REMOTE_HOST` option
374  should be set to the SSH hostname.  The executables and data files need to be
375  transferred to the device after compilation.  This is typically done via the
376  `rsync` make target.  After this, the lit runner can be used on the host
377  machine. It will prefix the benchmark and verification command lines with an
378  `ssh` command.
379
380  Example:
381
382  ```bash
383  % cmake -G Ninja -D CMAKE_C_COMPILER=path/to/clang \
384          -C ../test-suite/cmake/caches/target-arm64-iphoneos-internal.cmake \
385          -D TEST_SUITE_REMOTE_HOST=mydevice \
386          ../test-suite
387  % ninja
388  % ninja rsync
389  % llvm-lit -j1 -o result.json .
390  ```
391
392- You can specify a simulator for the target machine with the
393  `TEST_SUITE_RUN_UNDER` setting. The lit runner will prefix all benchmark
394  invocations with it.
395
396
397Running the test-suite via LNT
398------------------------------
399
400The LNT tool can run the test-suite. Use this when submitting test results to
401an LNT instance.  See
402[https://llvm.org/docs/lnt/tests.html#llvm-cmake-test-suite](https://llvm.org/docs/lnt/tests.html#llvm-cmake-test-suite)
403for details.
404
405Running the test-suite via Makefiles (deprecated)
406-------------------------------------------------
407
408**Note**: The test-suite comes with a set of Makefiles that are considered
409deprecated.  They do not support newer testing modes like `Bitcode` or
410`Microbenchmarks` and are harder to use.
411
412Old documentation is available in the
413[test-suite Makefile Guide](TestSuiteMakefileGuide).
414