File: README.rst

package info (click to toggle)
llvm-toolchain-8 1:8.0.1-9
  • links: PTS, VCS
  • area: main
  • in suites: bullseye, sid
  • size: 786,476 kB
  • sloc: cpp: 3,943,085; ansic: 645,291; asm: 370,138; python: 149,919; objc: 58,070; sh: 23,525; lisp: 12,365; perl: 8,030; pascal: 6,938; ml: 5,577; awk: 3,415; makefile: 2,669; cs: 2,027; xml: 868; ruby: 156
file content (343 lines) | stat: -rw-r--r-- 12,897 bytes parent folder | download | duplicates (4)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
========================================
How to Build the LLVM* OpenMP* Libraries
========================================
This repository requires `CMake <http://www.cmake.org/>`_ v2.8.0 or later.  LLVM
and Clang need a more recent version which also applies for in-tree builds.  For
more information than available in this document please see
`LLVM's CMake documentation <http://llvm.org/docs/CMake.html>`_ and the
`official documentation <https://cmake.org/cmake/help/v2.8.0/cmake.html>`_.

.. contents::
   :local:

How to Call CMake Initially, then Repeatedly
============================================
- When calling CMake for the first time, all needed compiler options must be
  specified on the command line.  After this initial call to CMake, the compiler
  definitions must not be included for further calls to CMake.  Other options
  can be specified on the command line multiple times including all definitions
  in the build options section below.
- Example of configuring, building, reconfiguring, rebuilding:

  .. code-block:: console

    $ mkdir build
    $ cd build
    $ cmake -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ ..  # Initial configuration
    $ make
    ...
    $ make clean
    $ cmake -DCMAKE_BUILD_TYPE=Debug ..                               # Second configuration
    $ make
    ...
    $ rm -rf *
    $ cmake -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++ ..        # Third configuration
    $ make

- Notice in the example how the compiler definitions are only specified for an
  empty build directory, but other build options are used at any time.
- The file ``CMakeCache.txt`` which is created after the first call to CMake is
  a configuration file which holds all values for the build options.  These
  values can be changed using a text editor to modify ``CMakeCache.txt`` as
  opposed to using definitions on the command line.
- To have CMake create a particular type of build generator file simply include
  the ``-G <Generator name>`` option:

  .. code-block:: console

    $ cmake -G "Unix Makefiles" ...

  You can see a list of generators CMake supports by executing the cmake command
  with no arguments.

Instructions to Build
=====================
.. code-block:: console

 $ cd openmp_top_level/ [ this directory with libomptarget/, runtime/, etc. ]
 $ mkdir build
 $ cd build

 [ Unix* Libraries ]
 $ cmake -DCMAKE_C_COMPILER=<C Compiler> -DCMAKE_CXX_COMPILER=<C++ Compiler> ..

 [ Windows* Libraries ]
 $ cmake -G <Generator Type> -DCMAKE_C_COMPILER=<C Compiler> -DCMAKE_CXX_COMPILER=<C++ Compiler> -DCMAKE_ASM_MASM_COMPILER=[ml | ml64] -DCMAKE_BUILD_TYPE=Release ..

 $ make
 $ make install

CMake Options
=============
Builds with CMake can be customized by means of options as already seen above.
One possibility is to pass them via the command line:

.. code-block:: console

  $ cmake -DOPTION=<value> path/to/source

.. note:: The first value listed is the respective default for that option.

Generic Options
---------------
For full documentation consult the CMake manual or execute
``cmake --help-variable VARIABLE_NAME`` to get information about a specific
variable.

**CMAKE_BUILD_TYPE** = ``Release|Debug|RelWithDebInfo``
  Build type can be ``Release``, ``Debug``, or ``RelWithDebInfo`` which chooses
  the optimization level and presence of debugging symbols.

**CMAKE_C_COMPILER** = <C compiler name>
  Specify the C compiler.

**CMAKE_CXX_COMPILER** = <C++ compiler name>
  Specify the C++ compiler.

**CMAKE_Fortran_COMPILER** = <Fortran compiler name>
  Specify the Fortran compiler. This option is only needed when
  **LIBOMP_FORTRAN_MODULES** is ``ON`` (see below).  So typically, a Fortran
  compiler is not needed during the build.

**CMAKE_ASM_MASM_COMPILER** = ``ml|ml64``
  This option is only relevant for Windows*.

Options for all Libraries
-------------------------

**OPENMP_ENABLE_WERROR** = ``OFF|ON``
  Treat warnings as errors and fail, if a compiler warning is triggered.

**OPENMP_LIBDIR_SUFFIX** = ``""``
  Extra suffix to append to the directory where libraries are to be installed.

**OPENMP_TEST_C_COMPILER** = ``${CMAKE_C_COMPILER}``
  Compiler to use for testing. Defaults to the compiler that was also used for
  building.

**OPENMP_TEST_CXX_COMPILER** = ``${CMAKE_CXX_COMPILER}``
  Compiler to use for testing. Defaults to the compiler that was also used for
  building.

**OPENMP_LLVM_TOOLS_DIR** = ``/path/to/built/llvm/tools``
  Additional path to search for LLVM tools needed by tests.

**OPENMP_LLVM_LIT_EXECUTABLE** = ``/path/to/llvm-lit``
  Specify full path to ``llvm-lit`` executable for running tests.  The default
  is to search the ``PATH`` and the directory in **OPENMP_LLVM_TOOLS_DIR**.

**OPENMP_FILECHECK_EXECUTABLE** = ``/path/to/FileCheck``
  Specify full path to ``FileCheck`` executable for running tests.  The default
  is to search the ``PATH`` and the directory in **OPENMP_LLVM_TOOLS_DIR**.

Options for ``libomp``
----------------------

**LIBOMP_ARCH** = ``aarch64|arm|i386|mic|mips|mips64|ppc64|ppc64le|x86_64``
  The default value for this option is chosen based on probing the compiler for
  architecture macros (e.g., is ``__x86_64__`` predefined by compiler?).

**LIBOMP_MIC_ARCH** = ``knc|knf``
  Intel(R) Many Integrated Core Architecture (Intel(R) MIC Architecture) to
  build for.  This value is ignored if **LIBOMP_ARCH** does not equal ``mic``.

**LIBOMP_OMP_VERSION** = ``50|45|40|30``
  OpenMP version to build for.  Older versions will disable certain
  functionality and entry points.

**LIBOMP_LIB_TYPE** = ``normal|profile|stubs``
  Library type can be ``normal``, ``profile``, or ``stubs``.

**LIBOMP_USE_VERSION_SYMBOLS** = ``ON|OFF``
  Use versioned symbols for building the library.  This option only makes sense
  for ELF based libraries where version symbols are supported (Linux*, some BSD*
  variants).  It is ``OFF`` by default for Windows* and macOS*, but ``ON`` for
  other Unix based operating systems.

**LIBOMP_ENABLE_SHARED** = ``ON|OFF``
  Build a shared library.  If this option is ``OFF``, static OpenMP libraries
  will be built instead of dynamic ones.

  .. note::

    Static libraries are not supported on Windows*.

**LIBOMP_FORTRAN_MODULES** = ``OFF|ON``
  Create the Fortran modules (requires Fortran compiler).

macOS* Fat Libraries
""""""""""""""""""""
On macOS* machines, it is possible to build universal (or fat) libraries which
include both i386 and x86_64 architecture objects in a single archive.

.. code-block:: console

  $ cmake -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_OSX_ARCHITECTURES='i386;x86_64' ..
  $ make

There is also an option **LIBOMP_OSX_ARCHITECTURES** which can be set in case
this is an LLVM source tree build. It will only apply for the ``libomp`` library
avoids having the entire LLVM/Clang build produce universal binaries.

Optional Features
"""""""""""""""""

**LIBOMP_USE_ADAPTIVE_LOCKS** = ``ON|OFF``
  Include adaptive locks, based on Intel(R) Transactional Synchronization
  Extensions (Intel(R) TSX).  This feature is x86 specific and turned ``ON``
  by default for IA-32 architecture and Intel(R) 64 architecture.

**LIBOMP_USE_INTERNODE_ALIGNMENT** = ``OFF|ON``
  Align certain data structures on 4096-byte.  This option is useful on
  multi-node systems where a small ``CACHE_LINE`` setting leads to false sharing.

**LIBOMP_OMPT_SUPPORT** = ``ON|OFF``
  Include support for the OpenMP Tools Interface (OMPT). 
  This option is supported and ``ON`` by default for x86, x86_64, AArch64, and 
  PPC64 on Linux* and macOS*.
  This option is ``OFF`` if this feature is not supported for the platform.

**LIBOMP_OMPT_OPTIONAL** = ``ON|OFF``
  Include support for optional OMPT functionality.  This option is ignored if
  **LIBOMP_OMPT_SUPPORT** is ``OFF``.

**LIBOMP_STATS** = ``OFF|ON``
  Include stats-gathering code.

**LIBOMP_USE_DEBUGGER** = ``OFF|ON``
  Include the friendly debugger interface.

**LIBOMP_USE_HWLOC** = ``OFF|ON``
  Use `OpenMPI's hwloc library <https://www.open-mpi.org/projects/hwloc/>`_ for
  topology detection and affinity.

**LIBOMP_HWLOC_INSTALL_DIR** = ``/path/to/hwloc/install/dir``
  Specify install location of hwloc.  The configuration system will look for
  ``hwloc.h`` in ``${LIBOMP_HWLOC_INSTALL_DIR}/include`` and the library in
  ``${LIBOMP_HWLOC_INSTALL_DIR}/lib``.  The default is ``/usr/local``.
  This option is only used if **LIBOMP_USE_HWLOC** is ``ON``.

Additional Compiler Flags
"""""""""""""""""""""""""

These flags are **appended**, they do not overwrite any of the preset flags.

**LIBOMP_CPPFLAGS** = <space-separated flags>
  Additional C preprocessor flags.

**LIBOMP_CFLAGS** = <space-separated flags>
  Additional C compiler flags.

**LIBOMP_CXXFLAGS** = <space-separated flags>
  Additional C++ compiler flags.

**LIBOMP_ASMFLAGS** = <space-separated flags>
  Additional assembler flags.

**LIBOMP_LDFLAGS** = <space-separated flags>
  Additional linker flags.

**LIBOMP_LIBFLAGS** = <space-separated flags>
  Additional libraries to link.

**LIBOMP_FFLAGS** = <space-separated flags>
  Additional Fortran compiler flags.

Options for ``libomptarget``
----------------------------

**LIBOMPTARGET_OPENMP_HEADER_FOLDER** = ``""``
  Path of the folder that contains ``omp.h``.  This is required for testing
  out-of-tree builds.

**LIBOMPTARGET_OPENMP_HOST_RTL_FOLDER** = ``""``
  Path of the folder that contains ``libomp.so``.  This is required for testing
  out-of-tree builds.

Options for ``NVPTX device RTL``
--------------------------------

**LIBOMPTARGET_NVPTX_ENABLE_BCLIB** = ``ON|OFF``
  Enable CUDA LLVM bitcode offloading device RTL. This is used for link time
  optimization of the OMP runtime and application code. This option is enabled
  by default if the build system determines that `CMAKE_C_COMPILER` is able to
  compile and link the library.

**LIBOMPTARGET_NVPTX_CUDA_COMPILER** = ``""``
  Location of a CUDA compiler capable of emitting LLVM bitcode. Currently only
  the Clang compiler is supported. This is only used when building the CUDA LLVM
  bitcode offloading device RTL. If unspecified and the CMake C compiler is
  Clang, then Clang is used.

**LIBOMPTARGET_NVPTX_BC_LINKER** = ``""``
  Location of a linker capable of linking LLVM bitcode objects. This is only
  used when building the CUDA LLVM bitcode offloading device RTL. If unspecified
  and the CMake C compiler is Clang and there exists a llvm-link binary in the
  directory containing Clang, then this llvm-link binary is used.

**LIBOMPTARGET_NVPTX_ALTERNATE_HOST_COMPILER** = ``""``
  Host compiler to use with NVCC. This compiler is not going to be used to
  produce any binary. Instead, this is used to overcome the input compiler
  checks done by NVCC. E.g. if using a default host compiler that is not
  compatible with NVCC, this option can be use to pass to NVCC a valid compiler
  to avoid the error.

 **LIBOMPTARGET_NVPTX_COMPUTE_CAPABILITIES** = ``35``
  List of CUDA compute capabilities that should be supported by the NVPTX
  device RTL. E.g. for compute capabilities 6.0 and 7.0, the option "60,70"
  should be used. Compute capability 3.5 is the minimum required.

 **LIBOMPTARGET_NVPTX_DEBUG** = ``OFF|ON``
  Enable printing of debug messages from the NVPTX device RTL.

Example Usages of CMake
=======================

Typical Invocations
-------------------

.. code-block:: console

  $ cmake -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ ..
  $ cmake -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++ ..
  $ cmake -DCMAKE_C_COMPILER=icc -DCMAKE_CXX_COMPILER=icpc ..

Advanced Builds with Various Options
------------------------------------

- Build the i386 Linux* library using GCC*

  .. code-block:: console

    $ cmake -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++ -DLIBOMP_ARCH=i386 ..

- Build the x86_64 debug Mac library using Clang*

  .. code-block:: console

    $ cmake -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DLIBOMP_ARCH=x86_64 -DCMAKE_BUILD_TYPE=Debug ..

- Build the library (architecture determined by probing compiler) using the
  Intel(R) C Compiler and the Intel(R) C++ Compiler.  Also, create Fortran
  modules with the Intel(R) Fortran Compiler.

  .. code-block:: console

    $ cmake -DCMAKE_C_COMPILER=icc -DCMAKE_CXX_COMPILER=icpc -DCMAKE_Fortran_COMPILER=ifort -DLIBOMP_FORTRAN_MODULES=on ..

- Have CMake find the C/C++ compiler and specify additional flags for the C
  compiler, preprocessor, and C++ compiler.

  .. code-blocks:: console

    $ cmake -DLIBOMP_CFLAGS='-specific-flag' -DLIBOMP_CPPFLAGS='-DNEW_FEATURE=1 -DOLD_FEATURE=0' -DLIBOMP_CXXFLAGS='--one-specific-flag --two-specific-flag' ..

- Build the stubs library

  .. code-blocks:: console

    $ cmake -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++ -DLIBOMP_LIB_TYPE=stubs ..

**Footnotes**

.. [*] Other names and brands may be claimed as the property of others.