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
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>Building LLVM with CMake</title>
<link rel="stylesheet" href="llvm.css" type="text/css">
</head>
<h1>
Building LLVM with CMake
</h1>
<ul>
<li><a href="#intro">Introduction</a></li>
<li><a href="#quickstart">Quick start</a></li>
<li><a href="#usage">Basic CMake usage</a>
<li><a href="#options">Options and variables</a>
<ul>
<li><a href="#freccmake">Frequently-used CMake variables</a></li>
<li><a href="#llvmvars">LLVM-specific variables</a></li>
</ul></li>
<li><a href="#testing">Executing the test suite</a>
<li><a href="#cross">Cross compiling</a>
<li><a href="#embedding">Embedding LLVM in your project</a>
<ul>
<li><a href="#passdev">Developing LLVM pass out of source</a></li>
</ul></li>
<li><a href="#specifics">Compiler/Platform specific topics</a>
<ul>
<li><a href="#msvc">Microsoft Visual C++</a></li>
</ul></li>
</ul>
<div class="doc_author">
<p>Written by <a href="mailto:ofv@wanadoo.es">Oscar Fuentes</a></p>
</div>
<!-- *********************************************************************** -->
<h2>
<a name="intro">Introduction</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p><a href="http://www.cmake.org/">CMake</a> is a cross-platform
build-generator tool. CMake does not build the project, it generates
the files needed by your build tool (GNU make, Visual Studio, etc) for
building LLVM.</p>
<p>If you are really anxious about getting a functional LLVM build,
go to the <a href="#quickstart">Quick start</a> section. If you
are a CMake novice, start on <a href="#usage">Basic CMake
usage</a> and then go back to the <a href="#quickstart">Quick
start</a> once you know what you are
doing. The <a href="#options">Options and variables</a> section
is a reference for customizing your build. If you already have
experience with CMake, this is the recommended starting point.
</div>
<!-- *********************************************************************** -->
<h2>
<a name="quickstart">Quick start</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p> We use here the command-line, non-interactive CMake interface </p>
<ol>
<li><p><a href="http://www.cmake.org/cmake/resources/software.html">Download</a>
and install CMake. Version 2.8 is the minimum required.</p>
<li><p>Open a shell. Your development tools must be reachable from this
shell through the PATH environment variable.</p>
<li><p>Create a directory for containing the build. It is not
supported to build LLVM on the source directory. cd to this
directory:</p>
<div class="doc_code">
<p><tt>mkdir mybuilddir</tt></p>
<p><tt>cd mybuilddir</tt></p>
</div>
<li><p>Execute this command on the shell
replacing <i>path/to/llvm/source/root</i> with the path to the
root of your LLVM source tree:</p>
<div class="doc_code">
<p><tt>cmake path/to/llvm/source/root</tt></p>
</div>
<p>CMake will detect your development environment, perform a
series of test and generate the files required for building
LLVM. CMake will use default values for all build
parameters. See the <a href="#options">Options and variables</a>
section for fine-tuning your build</p>
<p>This can fail if CMake can't detect your toolset, or if it
thinks that the environment is not sane enough. On this case
make sure that the toolset that you intend to use is the only
one reachable from the shell and that the shell itself is the
correct one for you development environment. CMake will refuse
to build MinGW makefiles if you have a POSIX shell reachable
through the PATH environment variable, for instance. You can
force CMake to use a given build tool, see
the <a href="#usage">Usage</a> section.</p>
</ol>
</div>
<!-- *********************************************************************** -->
<h2>
<a name="usage">Basic CMake usage</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p>This section explains basic aspects of CMake, mostly for
explaining those options which you may need on your day-to-day
usage.</p>
<p>CMake comes with extensive documentation in the form of html
files and on the cmake executable itself. Execute <i>cmake
--help</i> for further help options.</p>
<p>CMake requires to know for which build tool it shall generate
files (GNU make, Visual Studio, Xcode, etc). If not specified on
the command line, it tries to guess it based on you
environment. Once identified the build tool, CMake uses the
corresponding <i>Generator</i> for creating files for your build
tool. You can explicitly specify the generator with the command
line option <i>-G "Name of the generator"</i>. For knowing the
available generators on your platform, execute</p>
<div class="doc_code">
<p><tt>cmake --help</tt></p>
</div>
<p>This will list the generator's names at the end of the help
text. Generator's names are case-sensitive. Example:</p>
<div class="doc_code">
<p><tt>cmake -G "Visual Studio 8 2005" path/to/llvm/source/root</tt></p>
</div>
<p>For a given development platform there can be more than one
adequate generator. If you use Visual Studio "NMake Makefiles"
is a generator you can use for building with NMake. By default,
CMake chooses the more specific generator supported by your
development environment. If you want an alternative generator,
you must tell this to CMake with the <i>-G</i> option.</p>
<p>TODO: explain variables and cache. Move explanation here from
#options section.</p>
</div>
<!-- *********************************************************************** -->
<h2>
<a name="options">Options and variables</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p>Variables customize how the build will be generated. Options are
boolean variables, with possible values ON/OFF. Options and
variables are defined on the CMake command line like this:</p>
<div class="doc_code">
<p><tt>cmake -DVARIABLE=value path/to/llvm/source</tt></p>
</div>
<p>You can set a variable after the initial CMake invocation for
changing its value. You can also undefine a variable:</p>
<div class="doc_code">
<p><tt>cmake -UVARIABLE path/to/llvm/source</tt></p>
</div>
<p>Variables are stored on the CMake cache. This is a file
named <tt>CMakeCache.txt</tt> on the root of the build
directory. Do not hand-edit it.</p>
<p>Variables are listed here appending its type after a colon. It is
correct to write the variable and the type on the CMake command
line:</p>
<div class="doc_code">
<p><tt>cmake -DVARIABLE:TYPE=value path/to/llvm/source</tt></p>
</div>
<!-- ======================================================================= -->
<h3>
<a name="freccmake">Frequently-used CMake variables</a>
</h3>
<div>
<p>Here are listed some of the CMake variables that are used often,
along with a brief explanation and LLVM-specific notes. For full
documentation, check the CMake docs or execute <i>cmake
--help-variable VARIABLE_NAME</i>.</p>
<dl>
<dt><b>CMAKE_BUILD_TYPE</b>:STRING</dt>
<dd>Sets the build type for <i>make</i> based generators. Possible
values are Release, Debug, RelWithDebInfo and MinSizeRel. On
systems like Visual Studio the user sets the build type with the IDE
settings.</dd>
<dt><b>CMAKE_INSTALL_PREFIX</b>:PATH</dt>
<dd>Path where LLVM will be installed if "make install" is invoked
or the "INSTALL" target is built.</dd>
<dt><b>LLVM_LIBDIR_SUFFIX</b>:STRING</dt>
<dd>Extra suffix to append to the directory where libraries are to
be installed. On a 64-bit architecture, one could use
-DLLVM_LIBDIR_SUFFIX=64 to install libraries to /usr/lib64.</dd>
<dt><b>CMAKE_C_FLAGS</b>:STRING</dt>
<dd>Extra flags to use when compiling C source files.</dd>
<dt><b>CMAKE_CXX_FLAGS</b>:STRING</dt>
<dd>Extra flags to use when compiling C++ source files.</dd>
<dt><b>BUILD_SHARED_LIBS</b>:BOOL</dt>
<dd>Flag indicating is shared libraries will be built. Its default
value is OFF. Shared libraries are not supported on Windows and
not recommended in the other OSes.</dd>
</dl>
</div>
<!-- ======================================================================= -->
<h3>
<a name="llvmvars">LLVM-specific variables</a>
</h3>
<div>
<dl>
<dt><b>LLVM_TARGETS_TO_BUILD</b>:STRING</dt>
<dd>Semicolon-separated list of targets to build, or <i>all</i> for
building all targets. Case-sensitive. For Visual C++ defaults
to <i>X86</i>. On the other cases defaults to <i>all</i>. Example:
<i>-DLLVM_TARGETS_TO_BUILD="X86;PowerPC;Alpha"</i>.</dd>
<dt><b>LLVM_BUILD_TOOLS</b>:BOOL</dt>
<dd>Build LLVM tools. Defaults to ON. Targets for building each tool
are generated in any case. You can build an tool separately by
invoking its target. For example, you can build <i>llvm-as</i>
with a makefile-based system executing <i>make llvm-as</i> on the
root of your build directory.</dd>
<dt><b>LLVM_INCLUDE_TOOLS</b>:BOOL</dt>
<dd>Generate build targets for the LLVM tools. Defaults to
ON. You can use that option for disabling the generation of build
targets for the LLVM tools.</dd>
<dt><b>LLVM_BUILD_EXAMPLES</b>:BOOL</dt>
<dd>Build LLVM examples. Defaults to OFF. Targets for building each
example are generated in any case. See documentation
for <i>LLVM_BUILD_TOOLS</i> above for more details.</dd>
<dt><b>LLVM_INCLUDE_EXAMPLES</b>:BOOL</dt>
<dd>Generate build targets for the LLVM examples. Defaults to
ON. You can use that option for disabling the generation of build
targets for the LLVM examples.</dd>
<dt><b>LLVM_BUILD_TESTS</b>:BOOL</dt>
<dd>Build LLVM unit tests. Defaults to OFF. Targets for building
each unit test are generated in any case. You can build a specific
unit test with the target <i>UnitTestNameTests</i> (where at this
time <i>UnitTestName</i> can be ADT, Analysis, ExecutionEngine,
JIT, Support, Transform, VMCore; see the subdirectories
of <i>unittests</i> for an updated list.) It is possible to build
all unit tests with the target <i>UnitTests</i>.</dd>
<dt><b>LLVM_INCLUDE_TESTS</b>:BOOL</dt>
<dd>Generate build targets for the LLVM unit tests. Defaults to
ON. You can use that option for disabling the generation of build
targets for the LLVM unit tests.</dd>
<dt><b>LLVM_APPEND_VC_REV</b>:BOOL</dt>
<dd>Append version control revision info (svn revision number or git
revision id) to LLVM version string (stored in the PACKAGE_VERSION
macro). For this to work cmake must be invoked before the
build. Defaults to OFF.</dd>
<dt><b>LLVM_ENABLE_THREADS</b>:BOOL</dt>
<dd>Build with threads support, if available. Defaults to ON.</dd>
<dt><b>LLVM_ENABLE_ASSERTIONS</b>:BOOL</dt>
<dd>Enables code assertions. Defaults to OFF if and only if
CMAKE_BUILD_TYPE is <i>Release</i>.</dd>
<dt><b>LLVM_ENABLE_PIC</b>:BOOL</dt>
<dd>Add the <i>-fPIC</i> flag for the compiler command-line, if the
compiler supports this flag. Some systems, like Windows, do not
need this flag. Defaults to ON.</dd>
<dt><b>LLVM_ENABLE_WARNINGS</b>:BOOL</dt>
<dd>Enable all compiler warnings. Defaults to ON.</dd>
<dt><b>LLVM_ENABLE_PEDANTIC</b>:BOOL</dt>
<dd>Enable pedantic mode. This disable compiler specific extensions, is
possible. Defaults to ON.</dd>
<dt><b>LLVM_ENABLE_WERROR</b>:BOOL</dt>
<dd>Stop and fail build, if a compiler warning is
triggered. Defaults to OFF.</dd>
<dt><b>LLVM_BUILD_32_BITS</b>:BOOL</dt>
<dd>Build 32-bits executables and libraries on 64-bits systems. This
option is available only on some 64-bits unix systems. Defaults to
OFF.</dd>
<dt><b>LLVM_TARGET_ARCH</b>:STRING</dt>
<dd>LLVM target to use for native code generation. This is required
for JIT generation. It defaults to "host", meaning that it shall
pick the architecture of the machine where LLVM is being built. If
you are cross-compiling, set it to the target architecture
name.</dd>
<dt><b>LLVM_TABLEGEN</b>:STRING</dt>
<dd>Full path to a native TableGen executable (usually
named <i>tblgen</i>). This is intented for cross-compiling: if the
user sets this variable, no native TableGen will be created.</dd>
<dt><b>LLVM_LIT_ARGS</b>:STRING</dt>
<dd>Arguments given to lit.
<tt>make check</tt> and <tt>make clang-test</tt> are affected.
By default, <tt>"-sv --no-progress-bar"</tt>
on Visual C++ and Xcode,
<tt>"-sv"</tt> on others.</dd>
<dt><b>LLVM_LIT_TOOLS_DIR</b>:STRING</dt>
<dd>The path to GnuWin32 tools for tests. Valid on Windows host.
Defaults to "", then Lit seeks tools according to %PATH%.
Lit can find tools(eg. grep, sort, &c) on LLVM_LIT_TOOLS_DIR at first,
without specifying GnuWin32 to %PATH%.</dd>
<dt><b>LLVM_ENABLE_FFI</b>:BOOL</dt>
<dd>Indicates whether LLVM Interpreter will be linked with Foreign
Function Interface library. If the library or its headers are
installed on a custom location, you can set the variables
FFI_INCLUDE_DIR and FFI_LIBRARY_DIR. Defaults to OFF.</dd>
</dl>
</div>
</div>
<!-- *********************************************************************** -->
<h2>
<a name="testing">Executing the test suite</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p>Testing is performed when the <i>check</i> target is built. For
instance, if you are using makefiles, execute this command while on
the top level of your build directory:</p>
<div class="doc_code">
<p><tt>make check</tt></p>
</div>
<p>On Visual Studio, you may run tests to build the project "check".</p>
</div>
<!-- *********************************************************************** -->
<h2>
<a name="cross">Cross compiling</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p>See <a href="http://www.vtk.org/Wiki/CMake_Cross_Compiling">this
wiki page</a> for generic instructions on how to cross-compile
with CMake. It goes into detailed explanations and may seem
daunting, but it is not. On the wiki page there are several
examples including toolchain files. Go directly to
<a href="http://www.vtk.org/Wiki/CMake_Cross_Compiling#Information_how_to_set_up_various_cross_compiling_toolchains">this
section</a> for a quick solution.</p>
<p>Also see the <a href="#llvmvars">LLVM-specific variables</a>
section for variables used when cross-compiling.</p>
</div>
<!-- *********************************************************************** -->
<h2>
<a name="embedding">Embedding LLVM in your project</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p>The most difficult part of adding LLVM to the build of a project
is to determine the set of LLVM libraries corresponding to the set
of required LLVM features. What follows is an example of how to
obtain this information:</p>
<div class="doc_code">
<pre>
<b># A convenience variable:</b>
set(LLVM_ROOT "" CACHE PATH "Root of LLVM install.")
<b># A bit of a sanity check:</b>
if( NOT EXISTS ${LLVM_ROOT}/include/llvm )
message(FATAL_ERROR "LLVM_ROOT (${LLVM_ROOT}) is not a valid LLVM install")
endif()
<b># We incorporate the CMake features provided by LLVM:</b>
set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${LLVM_ROOT}/share/llvm/cmake")
include(LLVMConfig)
<b># Now set the header and library paths:</b>
include_directories( ${LLVM_INCLUDE_DIRS} )
link_directories( ${LLVM_LIBRARY_DIRS} )
add_definitions( ${LLVM_DEFINITIONS} )
<b># Let's suppose we want to build a JIT compiler with support for
# binary code (no interpreter):</b>
llvm_map_components_to_libraries(REQ_LLVM_LIBRARIES jit native)
<b># Finally, we link the LLVM libraries to our executable:</b>
target_link_libraries(mycompiler ${REQ_LLVM_LIBRARIES})
</pre>
</div>
<p>This assumes that LLVM_ROOT points to an install of LLVM. The
procedure works too for uninstalled builds although we need to take
care to add an <i>include_directories</i> for the location of the
headers on the LLVM source directory (if we are building
out-of-source.)</p>
<p>Alternativaly, you can utilize CMake's <i>find_package</i>
functionality. Here is an equivalent variant of snippet shown above:</p>
<div class="doc_code">
<pre>
find_package(LLVM)
if( NOT LLVM_FOUND )
message(FATAL_ERROR "LLVM package can't be found. Set CMAKE_PREFIX_PATH variable to LLVM's installation prefix.")
endif()
include_directories( ${LLVM_INCLUDE_DIRS} )
link_directories( ${LLVM_LIBRARY_DIRS} )
llvm_map_components_to_libraries(REQ_LLVM_LIBRARIES jit native)
target_link_libraries(mycompiler ${REQ_LLVM_LIBRARIES})
</pre>
</div>
<!-- ======================================================================= -->
<h3>
<a name="passdev">Developing LLVM pass out of source</a>
</h3>
<div>
<p>It is possible to develop LLVM passes against installed LLVM.
An example of project layout provided below:</p>
<div class="doc_code">
<pre>
<project dir>/
|
CMakeLists.txt
<pass name>/
|
CMakeLists.txt
Pass.cpp
...
</pre>
</div>
<p>Contents of <project dir>/CMakeLists.txt:</p>
<div class="doc_code">
<pre>
find_package(LLVM)
<b># Define add_llvm_* macro's.</b>
include(AddLLVM)
add_definitions(${LLVM_DEFINITIONS})
include_directories(${LLVM_INCLUDE_DIRS})
link_directories(${LLVM_LIBRARY_DIRS})
add_subdirectory(<pass name>)
</pre>
</div>
<p>Contents of <project dir>/<pass name>/CMakeLists.txt:</p>
<div class="doc_code">
<pre>
add_llvm_loadable_module(LLVMPassname
Pass.cpp
)
</pre>
</div>
<p>When you are done developing your pass, you may wish to integrate it
into LLVM source tree. You can achieve it in two easy steps:<br>
1. Copying <pass name> folder into <LLVM root>/lib/Transform directory.<br>
2. Adding "add_subdirectory(<pass name>)" line into <LLVM root>/lib/Transform/CMakeLists.txt</p>
</div>
<!-- *********************************************************************** -->
</div>
<!-- *********************************************************************** -->
<h2>
<a name="specifics">Compiler/Platform specific topics</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p>Notes for specific compilers and/or platforms.</p>
<h3>
<a name="msvc">Microsoft Visual C++</a>
</h3>
<div>
<dl>
<dt><b>LLVM_COMPILER_JOBS</b>:STRING</dt>
<dd>Specifies the maximum number of parallell compiler jobs to use
per project when building with msbuild or Visual Studio. Only supported for
Visual Studio 2008 and Visual Studio 2010 CMake generators. 0 means use all
processors. Default is 0.</dd>
</dl>
</div>
</div>
<!-- *********************************************************************** -->
<hr>
<address>
<a href="http://jigsaw.w3.org/css-validator/check/referer"><img
src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
<a href="http://validator.w3.org/check/referer"><img
src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
<a href="mailto:ofv@wanadoo.es">Oscar Fuentes</a><br>
<a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Last modified: $Date: 2010-08-09 03:59:36 +0100 (Mon, 9 Aug 2010) $
</address>
</body>
</html>
|
