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
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Getting Started with LLVM System</title>
<link rel="stylesheet" href="_static/llvm.css" type="text/css">
</head>
<body>
<h1>
Getting Started with the LLVM System
</h1>
<ul>
<li><a href="#overview">Overview</a>
<li><a href="#quickstart">Getting Started Quickly (A Summary)</a>
<li><a href="#requirements">Requirements</a>
<ol>
<li><a href="#hardware">Hardware</a></li>
<li><a href="#software">Software</a></li>
<li><a href="#brokengcc">Broken versions of GCC and other tools</a></li>
</ol></li>
<li><a href="#starting">Getting Started with LLVM</a>
<ol>
<li><a href="#terminology">Terminology and Notation</a></li>
<li><a href="#environment">Setting Up Your Environment</a></li>
<li><a href="#unpack">Unpacking the LLVM Archives</a></li>
<li><a href="#checkout">Checkout LLVM from Subversion</a></li>
<li><a href="#git_mirror">LLVM GIT mirror</a></li>
<li><a href="#config">Local LLVM Configuration</a></li>
<li><a href="#compile">Compiling the LLVM Suite Source Code</a></li>
<li><a href="#cross-compile">Cross-Compiling LLVM</a></li>
<li><a href="#objfiles">The Location of LLVM Object Files</a></li>
<li><a href="#optionalconfig">Optional Configuration Items</a></li>
</ol></li>
<li><a href="#layout">Program layout</a>
<ol>
<li><a href="#examples"><tt>llvm/examples</tt></a></li>
<li><a href="#include"><tt>llvm/include</tt></a></li>
<li><a href="#lib"><tt>llvm/lib</tt></a></li>
<li><a href="#projects"><tt>llvm/projects</tt></a></li>
<li><a href="#runtime"><tt>llvm/runtime</tt></a></li>
<li><a href="#test"><tt>llvm/test</tt></a></li>
<li><a href="#test-suite"><tt>test-suite</tt></a></li>
<li><a href="#tools"><tt>llvm/tools</tt></a></li>
<li><a href="#utils"><tt>llvm/utils</tt></a></li>
</ol></li>
<li><a href="#tutorial">An Example Using the LLVM Tool Chain</a>
<ol>
<li><a href="#tutorial4">Example with Clang</a></li>
</ol>
<li><a href="#problems">Common Problems</a>
<li><a href="#links">Links</a>
</ul>
<div class="doc_author">
<p>Written by:
<a href="mailto:criswell@uiuc.edu">John Criswell</a>,
<a href="mailto:sabre@nondot.org">Chris Lattner</a>,
<a href="http://misha.brukman.net/">Misha Brukman</a>,
<a href="http://www.cs.uiuc.edu/~vadve">Vikram Adve</a>, and
<a href="mailto:gshi1@uiuc.edu">Guochun Shi</a>.
</p>
</div>
<!-- *********************************************************************** -->
<h2>
<a name="overview">Overview</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p>Welcome to LLVM! In order to get started, you first need to know some
basic information.</p>
<p>First, LLVM comes in three pieces. The first piece is the LLVM
suite. This contains all of the tools, libraries, and header files
needed to use LLVM. It contains an assembler, disassembler, bitcode
analyzer and bitcode optimizer. It also contains basic regression tests that
can be used to test the LLVM tools and the Clang front end.</p>
<p>The second piece is the <a href="http://clang.llvm.org/">Clang</a> front end.
This component compiles C, C++, Objective C, and Objective C++ code into LLVM
bitcode. Once compiled into LLVM bitcode, a program can be manipulated with the
LLVM tools from the LLVM suite.
</p>
<p>
There is a third, optional piece called Test Suite. It is a suite of programs
with a testing harness that can be used to further test LLVM's functionality
and performance.
</p>
</div>
<!-- *********************************************************************** -->
<h2>
<a name="quickstart">Getting Started Quickly (A Summary)</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p>The LLVM Getting Started documentation may be out of date. So, the Clang
<a href="http://clang.llvm.org/get_started.html">Getting Started</a> page might
also be a good place to start.</p>
<p>Here's the short story for getting up and running quickly with LLVM:</p>
<ol>
<li>Read the documentation.</li>
<li>Read the documentation.</li>
<li>Remember that you were warned twice about reading the documentation.</li>
<li>Checkout LLVM:
<ul>
<li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
<li><tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
</ul>
</li>
<li>Checkout Clang:
<ul>
<li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
<li><tt>cd llvm/tools</tt>
<li><tt>svn co http://llvm.org/svn/llvm-project/cfe/trunk clang</tt></li>
</ul>
</li>
<li>Checkout Compiler-RT:
<ul>
<li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
<li><tt>cd llvm/projects</tt>
<li><tt>svn co http://llvm.org/svn/llvm-project/compiler-rt/trunk
compiler-rt</tt></li>
</ul>
</li>
<li>Get the Test Suite Source Code <b>[Optional]</b>
<ul>
<li><tt>cd <i>where-you-want-llvm-to-live</i></tt>
<li><tt>cd llvm/projects</tt>
<li><tt>svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite</tt></li>
</ul>
</li>
<li>Configure and build LLVM and Clang:
<ul>
<li><tt>cd <i>where-you-want-to-build-llvm</i></tt></li>
<li><tt>mkdir build</tt> (for building without polluting the source dir)</li>
<li><tt>cd build</tt></li>
<li><tt>../llvm/configure [options]</tt>
<br>Some common options:
<ul>
<li><tt>--prefix=<i>directory</i></tt> -
Specify for <i>directory</i> the full pathname of where you
want the LLVM tools and libraries to be installed (default
<tt>/usr/local</tt>).</li>
</ul>
<ul>
<li><tt>--enable-optimized</tt> -
Compile with optimizations enabled (default is NO).</li>
</ul>
<ul>
<li><tt>--enable-assertions</tt> -
Compile with assertion checks enabled (default is YES).</li>
</ul>
</li>
<li><tt>make [-j]</tt> - The -j specifies the number of jobs (commands) to
run simultaneously. This builds both LLVM and Clang for Debug+Asserts mode.
The --enabled-optimized configure option is used to specify a Release build.</li>
<li><tt>make check-all</tt> -
This run the regression tests to ensure everything is in working order.</li>
<li><tt>make update</tt> -
This command is used to update all the svn repositories at once, rather then
having to <tt>cd</tt> into the individual repositories and running
<tt>svn update</tt>.</li>
<li>It is also possible to use CMake instead of the makefiles. With CMake
it is also possible to generate project files for several IDEs: Eclipse
CDT4, CodeBlocks, Qt-Creator (use the CodeBlocks generator), KDevelop3.</li>
<li>If you get an "internal compiler error (ICE)" or test failures, see
<a href="#brokengcc">below</a>.</li>
</ul>
</li>
</ol>
<p>Consult the <a href="#starting">Getting Started with LLVM</a> section for
detailed information on configuring and compiling LLVM. See <a
href="#environment">Setting Up Your Environment</a> for tips that simplify
working with the Clang front end and LLVM tools. Go to <a href="#layout">Program
Layout</a> to learn about the layout of the source code tree.</p>
</div>
<!-- *********************************************************************** -->
<h2>
<a name="requirements">Requirements</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p>Before you begin to use the LLVM system, review the requirements given below.
This may save you some trouble by knowing ahead of time what hardware and
software you will need.</p>
<!-- ======================================================================= -->
<h3>
<a name="hardware">Hardware</a>
</h3>
<div>
<p>LLVM is known to work on the following platforms:</p>
<table cellpadding="3" summary="Known LLVM platforms">
<tr>
<th>OS</th>
<th>Arch</th>
<th>Compilers</th>
</tr>
<tr>
<td>AuroraUX</td>
<td>x86<sup><a href="#pf_1">1</a></sup></td>
<td>GCC</td>
</tr>
<tr>
<td>Linux</td>
<td>x86<sup><a href="#pf_1">1</a></sup></td>
<td>GCC</td>
</tr>
<tr>
<td>Linux</td>
<td>amd64</td>
<td>GCC</td>
</tr>
<tr>
<td>Solaris</td>
<td>V9 (Ultrasparc)</td>
<td>GCC</td>
</tr>
<tr>
<td>FreeBSD</td>
<td>x86<sup><a href="#pf_1">1</a></sup></td>
<td>GCC</td>
</tr>
<tr>
<td>FreeBSD</td>
<td>amd64</td>
<td>GCC</td>
</tr>
<tr>
<td>MacOS X<sup><a href="#pf_2">2</a></sup></td>
<td>PowerPC</td>
<td>GCC</td>
</tr>
<tr>
<td>MacOS X<sup><a href="#pf_2">2</a>,<a href="#pf_9">9</a></sup></td>
<td>x86</td>
<td>GCC</td>
</tr>
<tr>
<td>Cygwin/Win32</td>
<td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_8">8</a>,
<a href="#pf_11">11</a></sup></td>
<td>GCC 3.4.X, binutils 2.20</td>
</tr>
<tr>
<td>MinGW/Win32</td>
<td>x86<sup><a href="#pf_1">1</a>,<a href="#pf_6">6</a>,
<a href="#pf_8">8</a>, <a href="#pf_10">10</a>,
<a href="#pf_11">11</a></sup></td>
<td>GCC 3.4.X, binutils 2.20</td>
</tr>
</table>
<p>LLVM has partial support for the following platforms:</p>
<table summary="LLVM partial platform support">
<tr>
<th>OS</th>
<th>Arch</th>
<th>Compilers</th>
</tr>
<tr>
<td>Windows</td>
<td>x86<sup><a href="#pf_1">1</a></sup></td>
<td>Visual Studio 2008 or higher<sup><a href="#pf_4">4</a>,<a href="#pf_5">5</a></sup></td>
<tr>
<td>AIX<sup><a href="#pf_3">3</a>,<a href="#pf_4">4</a></sup></td>
<td>PowerPC</td>
<td>GCC</td>
</tr>
<tr>
<td>Linux<sup><a href="#pf_3">3</a>,<a href="#pf_5">5</a></sup></td>
<td>PowerPC</td>
<td>GCC</td>
</tr>
<tr>
<td>Linux<sup><a href="#pf_7">7</a></sup></td>
<td>Alpha</td>
<td>GCC</td>
</tr>
<tr>
<td>Linux<sup><a href="#pf_7">7</a></sup></td>
<td>Itanium (IA-64)</td>
<td>GCC</td>
</tr>
<tr>
<td>HP-UX<sup><a href="#pf_7">7</a></sup></td>
<td>Itanium (IA-64)</td>
<td>HP aCC</td>
</tr>
<tr>
<td>Windows x64</td>
<td>x86-64</td>
<td>mingw-w64's GCC-4.5.x<sup><a href="#pf_12">12</a></sup></td>
</tr>
</table>
<p><b>Notes:</b></p>
<div class="doc_notes">
<ol>
<li><a name="pf_1">Code generation supported for Pentium processors and
up</a></li>
<li><a name="pf_2">Code generation supported for 32-bit ABI only</a></li>
<li><a name="pf_3">No native code generation</a></li>
<li><a name="pf_4">Build is not complete: one or more tools do not link or function</a></li>
<li><a name="pf_5">The GCC-based C/C++ frontend does not build</a></li>
<li><a name="pf_6">The port is done using the MSYS shell.</a></li>
<li><a name="pf_7">Native code generation exists but is not complete.</a></li>
<li><a name="pf_8">Binutils 2.20 or later is required to build the assembler
generated by LLVM properly.</a></li>
<li><a name="pf_9">Xcode 2.5 and gcc 4.0.1</a> (Apple Build 5370) will trip
internal LLVM assert messages when compiled for Release at optimization
levels greater than 0 (i.e., <i>"-O1"</i> and higher).
Add <i>OPTIMIZE_OPTION="-O0"</i> to the build command line
if compiling for LLVM Release or bootstrapping the LLVM toolchain.</li>
<li><a name="pf_10">For MSYS/MinGW on Windows, be sure to install the MSYS
version of the perl package, and be sure it appears in your path
before any Windows-based versions such as Strawberry Perl and
ActivePerl, as these have Windows-specifics that will cause the
build to fail.</a></li>
<li><a name="pf_11">To use LLVM modules on Win32-based system,
you may configure LLVM with <i>"--enable-shared"</i>.</a></li>
<li><a name="pf_12">To compile SPU backend, you need to add
<tt>"LDFLAGS=-Wl,--stack,16777216"</tt> to configure.</a></li>
</ol>
</div>
<p>Note that you will need about 1-3 GB of space for a full LLVM build in Debug
mode, depending on the system (it is so large because of all the debugging
information and the fact that the libraries are statically linked into multiple
tools). If you do not need many of the tools and you are space-conscious, you
can pass <tt>ONLY_TOOLS="tools you need"</tt> to make. The Release build
requires considerably less space.</p>
<p>The LLVM suite <i>may</i> compile on other platforms, but it is not
guaranteed to do so. If compilation is successful, the LLVM utilities should be
able to assemble, disassemble, analyze, and optimize LLVM bitcode. Code
generation should work as well, although the generated native code may not work
on your platform.</p>
</div>
<!-- ======================================================================= -->
<h3>
<a name="software">Software</a>
</h3>
<div>
<p>Compiling LLVM requires that you have several software packages
installed. The table below lists those required packages. The Package column
is the usual name for the software package that LLVM depends on. The Version
column provides "known to work" versions of the package. The Notes column
describes how LLVM uses the package and provides other details.</p>
<table summary="Packages required to compile LLVM">
<tr><th>Package</th><th>Version</th><th>Notes</th></tr>
<tr>
<td><a href="http://savannah.gnu.org/projects/make">GNU Make</a></td>
<td>3.79, 3.79.1</td>
<td>Makefile/build processor</td>
</tr>
<tr>
<td><a href="http://gcc.gnu.org/">GCC</a></td>
<td>3.4.2</td>
<td>C/C++ compiler<sup><a href="#sf1">1</a></sup></td>
</tr>
<tr>
<td><a href="http://www.gnu.org/software/texinfo/">TeXinfo</a></td>
<td>4.5</td>
<td>For building the CFE</td>
</tr>
<tr>
<td><a href="http://subversion.tigris.org/project_packages.html">SVN</a></td>
<td>≥1.3</td>
<td>Subversion access to LLVM<sup><a href="#sf2">2</a></sup></td>
</tr>
<!-- FIXME:
Do we support dg?
Are DejaGnu and expect obsolete?
Shall we mention Python? -->
<tr>
<td><a href="http://savannah.gnu.org/projects/dejagnu">DejaGnu</a></td>
<td>1.4.2</td>
<td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
</tr>
<tr>
<td><a href="http://www.tcl.tk/software/tcltk/">tcl</a></td>
<td>8.3, 8.4</td>
<td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
</tr>
<tr>
<td><a href="http://expect.nist.gov/">expect</a></td>
<td>5.38.0</td>
<td>Automated test suite<sup><a href="#sf3">3</a></sup></td>
</tr>
<tr>
<td><a href="http://www.perl.com/download.csp">perl</a></td>
<td>≥5.6.0</td>
<td>Utilities</td>
</tr>
<tr>
<td><a href="http://savannah.gnu.org/projects/m4">GNU M4</a>
<td>1.4</td>
<td>Macro processor for configuration<sup><a href="#sf4">4</a></sup></td>
</tr>
<tr>
<td><a href="http://www.gnu.org/software/autoconf/">GNU Autoconf</a></td>
<td>2.60</td>
<td>Configuration script builder<sup><a href="#sf4">4</a></sup></td>
</tr>
<tr>
<td><a href="http://www.gnu.org/software/automake/">GNU Automake</a></td>
<td>1.9.6</td>
<td>aclocal macro generator<sup><a href="#sf4">4</a></sup></td>
</tr>
<tr>
<td><a href="http://savannah.gnu.org/projects/libtool">libtool</a></td>
<td>1.5.22</td>
<td>Shared library manager<sup><a href="#sf4">4</a></sup></td>
</tr>
</table>
<p><b>Notes:</b></p>
<div class="doc_notes">
<ol>
<li><a name="sf1">Only the C and C++ languages are needed so there's no
need to build the other languages for LLVM's purposes.</a> See
<a href="#brokengcc">below</a> for specific version info.</li>
<li><a name="sf2">You only need Subversion if you intend to build from the
latest LLVM sources. If you're working from a release distribution, you
don't need Subversion.</a></li>
<li><a name="sf3">Only needed if you want to run the automated test
suite in the <tt>llvm/test</tt> directory.</a></li>
<li><a name="sf4">If you want to make changes to the configure scripts,
you will need GNU autoconf (2.60), and consequently, GNU M4 (version 1.4
or higher). You will also need automake (1.9.6). We only use aclocal
from that package.</a></li>
</ol>
</div>
<p>Additionally, your compilation host is expected to have the usual
plethora of Unix utilities. Specifically:</p>
<ul>
<li><b>ar</b> - archive library builder</li>
<li><b>bzip2*</b> - bzip2 command for distribution generation</li>
<li><b>bunzip2*</b> - bunzip2 command for distribution checking</li>
<li><b>chmod</b> - change permissions on a file</li>
<li><b>cat</b> - output concatenation utility</li>
<li><b>cp</b> - copy files</li>
<li><b>date</b> - print the current date/time </li>
<li><b>echo</b> - print to standard output</li>
<li><b>egrep</b> - extended regular expression search utility</li>
<li><b>find</b> - find files/dirs in a file system</li>
<li><b>grep</b> - regular expression search utility</li>
<li><b>gzip*</b> - gzip command for distribution generation</li>
<li><b>gunzip*</b> - gunzip command for distribution checking</li>
<li><b>install</b> - install directories/files </li>
<li><b>mkdir</b> - create a directory</li>
<li><b>mv</b> - move (rename) files</li>
<li><b>ranlib</b> - symbol table builder for archive libraries</li>
<li><b>rm</b> - remove (delete) files and directories</li>
<li><b>sed</b> - stream editor for transforming output</li>
<li><b>sh</b> - Bourne shell for make build scripts</li>
<li><b>tar</b> - tape archive for distribution generation</li>
<li><b>test</b> - test things in file system</li>
<li><b>unzip*</b> - unzip command for distribution checking</li>
<li><b>zip*</b> - zip command for distribution generation</li>
</ul>
</div>
<!-- ======================================================================= -->
<h3>
<a name="brokengcc">Broken versions of GCC and other tools</a>
</h3>
<div>
<p>LLVM is very demanding of the host C++ compiler, and as such tends to expose
bugs in the compiler. In particular, several versions of GCC crash when trying
to compile LLVM. We routinely use GCC 4.2 (and higher) or Clang.
Other versions of GCC will probably work as well. GCC versions listed
here are known to not work. If you are using one of these versions, please try
to upgrade your GCC to something more recent. If you run into a problem with a
version of GCC not listed here, please <a href="mailto:llvmdev@cs.uiuc.edu">let
us know</a>. Please use the "<tt>gcc -v</tt>" command to find out which version
of GCC you are using.
</p>
<p><b>GCC versions prior to 3.0</b>: GCC 2.96.x and before had several
problems in the STL that effectively prevent it from compiling LLVM.
</p>
<p><b>GCC 3.2.2 and 3.2.3</b>: These versions of GCC fails to compile LLVM with
a bogus template error. This was fixed in later GCCs.</p>
<p><b>GCC 3.3.2</b>: This version of GCC suffered from a <a
href="http://gcc.gnu.org/PR13392">serious bug</a> which causes it to crash in
the "<tt>convert_from_eh_region_ranges_1</tt>" GCC function.</p>
<p><b>Cygwin GCC 3.3.3</b>: The version of GCC 3.3.3 commonly shipped with
Cygwin does not work.</p>
<p><b>SuSE GCC 3.3.3</b>: The version of GCC 3.3.3 shipped with SuSE 9.1 (and
possibly others) does not compile LLVM correctly (it appears that exception
handling is broken in some cases). Please download the FSF 3.3.3 or upgrade
to a newer version of GCC.</p>
<p><b>GCC 3.4.0 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
code generator, causing an infinite loop in the llvm-gcc build when built
with optimizations enabled (i.e. a release build).</p>
<p><b>GCC 3.4.2 on linux/x86 (32-bit)</b>: GCC miscompiles portions of the
code generator at -O3, as with 3.4.0. However gcc 3.4.2 (unlike 3.4.0)
correctly compiles LLVM at -O2. A work around is to build release LLVM
builds with "make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2 ..."</p>
<p><b>GCC 3.4.x on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1056">
miscompiles portions of LLVM</a>.</p>
<p><b>GCC 3.4.4 (CodeSourcery ARM 2005q3-2)</b>: this compiler miscompiles LLVM
when building with optimizations enabled. It appears to work with
"<tt>make ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O1</tt>" or build a debug
build.</p>
<p><b>IA-64 GCC 4.0.0</b>: The IA-64 version of GCC 4.0.0 is known to
miscompile LLVM.</p>
<p><b>Apple Xcode 2.3</b>: GCC crashes when compiling LLVM at -O3 (which is the
default with ENABLE_OPTIMIZED=1. To work around this, build with
"ENABLE_OPTIMIZED=1 OPTIMIZE_OPTION=-O2".</p>
<p><b>GCC 4.1.1</b>: GCC fails to build LLVM with template concept check errors
compiling some files. At the time of this writing, GCC mainline (4.2)
did not share the problem.</p>
<p><b>GCC 4.1.1 on X86-64/amd64</b>: GCC <a href="http://llvm.org/PR1063">
miscompiles portions of LLVM</a> when compiling llvm itself into 64-bit
code. LLVM will appear to mostly work but will be buggy, e.g. failing
portions of its testsuite.</p>
<p><b>GCC 4.1.2 on OpenSUSE</b>: Seg faults during libstdc++ build and on x86_64
platforms compiling md5.c gets a mangled constant.</p>
<p><b>GCC 4.1.2 (20061115 (prerelease) (Debian 4.1.1-21)) on Debian</b>: Appears
to miscompile parts of LLVM 2.4. One symptom is ValueSymbolTable complaining
about symbols remaining in the table on destruction.</p>
<p><b>GCC 4.1.2 20071124 (Red Hat 4.1.2-42)</b>: Suffers from the same symptoms
as the previous one. It appears to work with ENABLE_OPTIMIZED=0 (the default).</p>
<p><b>Cygwin GCC 4.3.2 20080827 (beta) 2</b>:
Users <a href="http://llvm.org/PR4145">reported</a> various problems related
with link errors when using this GCC version.</p>
<p><b>Debian GCC 4.3.2 on X86</b>: Crashes building some files in LLVM 2.6.</p>
<p><b>GCC 4.3.3 (Debian 4.3.3-10) on ARM</b>: Miscompiles parts of LLVM 2.6
when optimizations are turned on. The symptom is an infinite loop in
FoldingSetImpl::RemoveNode while running the code generator.</p>
<p><b>SUSE 11 GCC 4.3.4</b>: Miscompiles LLVM, causing crashes in ValueHandle logic.</p>
<p><b>GCC 4.3.5 and GCC 4.4.5 on ARM</b>: These can miscompile <tt>value >>
1</tt> even at -O0. A test failure in <tt>test/Assembler/alignstack.ll</tt> is
one symptom of the problem.
<p><b>GNU ld 2.16.X</b>. Some 2.16.X versions of the ld linker will produce very
long warning messages complaining that some ".gnu.linkonce.t.*" symbol was
defined in a discarded section. You can safely ignore these messages as they are
erroneous and the linkage is correct. These messages disappear using ld
2.17.</p>
<p><b>GNU binutils 2.17</b>: Binutils 2.17 contains <a
href="http://sourceware.org/bugzilla/show_bug.cgi?id=3111">a bug</a> which
causes huge link times (minutes instead of seconds) when building LLVM. We
recommend upgrading to a newer version (2.17.50.0.4 or later).</p>
<p><b>GNU Binutils 2.19.1 Gold</b>: This version of Gold contained
<a href="http://sourceware.org/bugzilla/show_bug.cgi?id=9836">a bug</a>
which causes intermittent failures when building LLVM with position independent
code. The symptom is an error about cyclic dependencies. We recommend
upgrading to a newer version of Gold.</p>
</div>
</div>
<!-- *********************************************************************** -->
<h2>
<a name="starting">Getting Started with LLVM</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p>The remainder of this guide is meant to get you up and running with
LLVM and to give you some basic information about the LLVM environment.</p>
<p>The later sections of this guide describe the <a
href="#layout">general layout</a> of the LLVM source tree, a <a
href="#tutorial">simple example</a> using the LLVM tool chain, and <a
href="#links">links</a> to find more information about LLVM or to get
help via e-mail.</p>
<!-- ======================================================================= -->
<h3>
<a name="terminology">Terminology and Notation</a>
</h3>
<div>
<p>Throughout this manual, the following names are used to denote paths
specific to the local system and working environment. <i>These are not
environment variables you need to set but just strings used in the rest
of this document below</i>. In any of the examples below, simply replace
each of these names with the appropriate pathname on your local system.
All these paths are absolute:</p>
<dl>
<dt>SRC_ROOT
<dd>
This is the top level directory of the LLVM source tree.
<br><br>
<dt>OBJ_ROOT
<dd>
This is the top level directory of the LLVM object tree (i.e. the
tree where object files and compiled programs will be placed. It
can be the same as SRC_ROOT).
<br><br>
</dl>
</div>
<!-- ======================================================================= -->
<h3>
<a name="environment">Setting Up Your Environment</a>
</h3>
<div>
<p>
In order to compile and use LLVM, you may need to set some environment
variables.
<dl>
<dt><tt>LLVM_LIB_SEARCH_PATH</tt>=<tt>/path/to/your/bitcode/libs</tt></dt>
<dd>[Optional] This environment variable helps LLVM linking tools find the
locations of your bitcode libraries. It is provided only as a
convenience since you can specify the paths using the -L options of the
tools and the C/C++ front-end will automatically use the bitcode files
installed in its
<tt>lib</tt> directory.</dd>
</dl>
</div>
<!-- ======================================================================= -->
<h3>
<a name="unpack">Unpacking the LLVM Archives</a>
</h3>
<div>
<p>
If you have the LLVM distribution, you will need to unpack it before you
can begin to compile it. LLVM is distributed as a set of two files: the LLVM
suite and the LLVM GCC front end compiled for your platform. There is an
additional test suite that is optional. Each file is a TAR archive that is
compressed with the gzip program.
</p>
<p>The files are as follows, with <em>x.y</em> marking the version number:
<dl>
<dt><tt>llvm-x.y.tar.gz</tt></dt>
<dd>Source release for the LLVM libraries and tools.<br></dd>
<dt><tt>llvm-test-x.y.tar.gz</tt></dt>
<dd>Source release for the LLVM test-suite.</dd>
<dt><tt>llvm-gcc-4.2-x.y.source.tar.gz</tt></dt>
<dd>Source release of the llvm-gcc-4.2 front end. See README.LLVM in the root
directory for build instructions.<br></dd>
<dt><tt>llvm-gcc-4.2-x.y-platform.tar.gz</tt></dt>
<dd>Binary release of the llvm-gcc-4.2 front end for a specific platform.<br></dd>
</dl>
</div>
<!-- ======================================================================= -->
<h3>
<a name="checkout">Checkout LLVM from Subversion</a>
</h3>
<div>
<p>If you have access to our Subversion repository, you can get a fresh copy of
the entire source code. All you need to do is check it out from Subversion as
follows:</p>
<ul>
<li><tt>cd <i>where-you-want-llvm-to-live</i></tt></li>
<li>Read-Only: <tt>svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm</tt></li>
<li>Read-Write:<tt>svn co https://user@llvm.org/svn/llvm-project/llvm/trunk
llvm</tt></li>
</ul>
<p>This will create an '<tt>llvm</tt>' directory in the current
directory and fully populate it with the LLVM source code, Makefiles,
test directories, and local copies of documentation files.</p>
<p>If you want to get a specific release (as opposed to the most recent
revision), you can checkout it from the '<tt>tags</tt>' directory (instead of
'<tt>trunk</tt>'). The following releases are located in the following
subdirectories of the '<tt>tags</tt>' directory:</p>
<ul>
<li>Release 3.1: <b>RELEASE_31/final</b></li>
<li>Release 3.0: <b>RELEASE_30/final</b></li>
<li>Release 2.9: <b>RELEASE_29/final</b></li>
<li>Release 2.8: <b>RELEASE_28</b></li>
<li>Release 2.7: <b>RELEASE_27</b></li>
<li>Release 2.6: <b>RELEASE_26</b></li>
<li>Release 2.5: <b>RELEASE_25</b></li>
<li>Release 2.4: <b>RELEASE_24</b></li>
<li>Release 2.3: <b>RELEASE_23</b></li>
<li>Release 2.2: <b>RELEASE_22</b></li>
<li>Release 2.1: <b>RELEASE_21</b></li>
<li>Release 2.0: <b>RELEASE_20</b></li>
<li>Release 1.9: <b>RELEASE_19</b></li>
<li>Release 1.8: <b>RELEASE_18</b></li>
<li>Release 1.7: <b>RELEASE_17</b></li>
<li>Release 1.6: <b>RELEASE_16</b></li>
<li>Release 1.5: <b>RELEASE_15</b></li>
<li>Release 1.4: <b>RELEASE_14</b></li>
<li>Release 1.3: <b>RELEASE_13</b></li>
<li>Release 1.2: <b>RELEASE_12</b></li>
<li>Release 1.1: <b>RELEASE_11</b></li>
<li>Release 1.0: <b>RELEASE_1</b></li>
</ul>
<p>If you would like to get the LLVM test suite (a separate package as of 1.4),
you get it from the Subversion repository:</p>
<div class="doc_code">
<pre>
% cd llvm/projects
% svn co http://llvm.org/svn/llvm-project/test-suite/trunk test-suite
</pre>
</div>
<p>By placing it in the <tt>llvm/projects</tt>, it will be automatically
configured by the LLVM configure script as well as automatically updated when
you run <tt>svn update</tt>.</p>
</div>
<!-- ======================================================================= -->
<h3>
<a name="git_mirror">GIT mirror</a>
</h3>
<div>
<p>GIT mirrors are available for a number of LLVM subprojects. These mirrors
sync automatically with each Subversion commit and contain all necessary
git-svn marks (so, you can recreate git-svn metadata locally). Note that right
now mirrors reflect only <tt>trunk</tt> for each project. You can do the
read-only GIT clone of LLVM via:</p>
<pre class="doc_code">
git clone http://llvm.org/git/llvm.git
</pre>
<p>If you want to check out clang too, run:</p>
<pre class="doc_code">
git clone http://llvm.org/git/llvm.git
cd llvm/tools
git clone http://llvm.org/git/clang.git
</pre>
<p>
Since the upstream repository is in Subversion, you should use
<tt>"git pull --rebase"</tt>
instead of <tt>"git pull"</tt> to avoid generating a non-linear
history in your clone.
To configure <tt>"git pull"</tt> to pass <tt>--rebase</tt> by default
on the master branch, run the following command:
</p>
<pre class="doc_code">
git config branch.master.rebase true
</pre>
<h4>Sending patches with Git</h4>
<div>
<p>
Please read <a href="DeveloperPolicy.html#patches">Developer Policy</a>, too.
</p>
<p>
Assume <tt>master</tt> points the upstream and <tt>mybranch</tt> points your
working branch, and <tt>mybranch</tt> is rebased onto <tt>master</tt>.
At first you may check sanity of whitespaces:
</p>
<pre class="doc_code">
git diff --check master..mybranch
</pre>
<p>
The easiest way to generate a patch is as below:
</p>
<pre class="doc_code">
git diff master..mybranch > /path/to/mybranch.diff
</pre>
<p>
It is a little different from svn-generated diff. git-diff-generated diff has
prefixes like <tt>a/</tt> and <tt>b/</tt>. Don't worry, most developers might
know it could be accepted with <tt>patch -p1 -N</tt>.
</p>
<p>
But you may generate patchset with git-format-patch. It generates
by-each-commit patchset. To generate patch files to attach to your article:
</p>
<pre class="doc_code">
git format-patch --no-attach master..mybranch -o /path/to/your/patchset
</pre>
<p>
If you would like to send patches directly, you may use git-send-email or
git-imap-send. Here is an example to generate the patchset in Gmail's [Drafts].
</p>
<pre class="doc_code">
git format-patch --attach master..mybranch --stdout | git imap-send
</pre>
<p>
Then, your .git/config should have [imap] sections.
</p>
<pre class="doc_code">
[imap]
host = imaps://imap.gmail.com
user = <em>your.gmail.account</em>@gmail.com
pass = <em>himitsu!</em>
port = 993
sslverify = false
; in English
folder = "[Gmail]/Drafts"
; example for Japanese, "Modified UTF-7" encoded.
folder = "[Gmail]/&Tgtm+DBN-"
; example for Traditional Chinese
folder = "[Gmail]/&g0l6Pw-"
</pre>
</div>
<h4>For developers to work with git-svn</h4>
<div>
<p>To set up clone from which you can submit code using
<tt>git-svn</tt>, run:</p>
<pre class="doc_code">
git clone http://llvm.org/git/llvm.git
cd llvm
git svn init https://llvm.org/svn/llvm-project/llvm/trunk --username=<username>
git config svn-remote.svn.fetch :refs/remotes/origin/master
git svn rebase -l # -l avoids fetching ahead of the git mirror.
# If you have clang too:
cd tools
git clone http://llvm.org/git/clang.git
cd clang
git svn init https://llvm.org/svn/llvm-project/cfe/trunk --username=<username>
git config svn-remote.svn.fetch :refs/remotes/origin/master
git svn rebase -l
</pre>
<p>To update this clone without generating git-svn tags that conflict
with the upstream git repo, run:</p>
<pre class="doc_code">
git fetch && (cd tools/clang && git fetch) # Get matching revisions of both trees.
git checkout master
git svn rebase -l
(cd tools/clang &&
git checkout master &&
git svn rebase -l)
</pre>
<p>This leaves your working directories on their master branches, so
you'll need to <tt>checkout</tt> each working branch individually and
<tt>rebase</tt> it on top of its parent branch. (Note: This script is
intended for relative newbies to git. If you have more experience,
you can likely improve on it.)</p>
<p>The git-svn metadata can get out of sync after you mess around with
branches and <code>dcommit</code>. When that happens, <code>git svn
dcommit</code> stops working, complaining about files with uncommitted
changes. The fix is to rebuild the metadata:</p>
<pre class="doc_code">
rm -rf .git/svn
git svn rebase -l
</pre>
</div>
</div>
<!-- ======================================================================= -->
<h3>
<a name="config">Local LLVM Configuration</a>
</h3>
<div>
<p>Once checked out from the Subversion repository, the LLVM suite source
code must be
configured via the <tt>configure</tt> script. This script sets variables in the
various <tt>*.in</tt> files, most notably <tt>llvm/Makefile.config</tt> and
<tt>llvm/include/Config/config.h</tt>. It also populates <i>OBJ_ROOT</i> with
the Makefiles needed to begin building LLVM.</p>
<p>The following environment variables are used by the <tt>configure</tt>
script to configure the build system:</p>
<table summary="LLVM configure script environment variables">
<tr><th>Variable</th><th>Purpose</th></tr>
<tr>
<td>CC</td>
<td>Tells <tt>configure</tt> which C compiler to use. By default,
<tt>configure</tt> will look for the first GCC C compiler in
<tt>PATH</tt>. Use this variable to override
<tt>configure</tt>'s default behavior.</td>
</tr>
<tr>
<td>CXX</td>
<td>Tells <tt>configure</tt> which C++ compiler to use. By default,
<tt>configure</tt> will look for the first GCC C++ compiler in
<tt>PATH</tt>. Use this variable to override
<tt>configure</tt>'s default behavior.</td>
</tr>
</table>
<p>The following options can be used to set or enable LLVM specific options:</p>
<dl>
<dt><i>--enable-optimized</i></dt>
<dd>
Enables optimized compilation (debugging symbols are removed
and GCC optimization flags are enabled). Note that this is the default
setting if you are using the LLVM distribution. The default behavior
of an Subversion checkout is to use an unoptimized build (also known as a
debug build).
<br><br>
</dd>
<dt><i>--enable-debug-runtime</i></dt>
<dd>
Enables debug symbols in the runtime libraries. The default is to strip
debug symbols from the runtime libraries.
</dd>
<dt><i>--enable-jit</i></dt>
<dd>
Compile the Just In Time (JIT) compiler functionality. This is not
available
on all platforms. The default is dependent on platform, so it is best
to explicitly enable it if you want it.
<br><br>
</dd>
<dt><i>--enable-targets=</i><tt>target-option</tt></dt>
<dd>Controls which targets will be built and linked into llc. The default
value for <tt>target_options</tt> is "all" which builds and links all
available targets. The value "host-only" can be specified to build only a
native compiler (no cross-compiler targets available). The "native" target is
selected as the target of the build host. You can also specify a comma
separated list of target names that you want available in llc. The target
names use all lower case. The current set of targets is: <br>
<tt>arm, cpp, hexagon, mblaze, mips, mipsel, msp430, powerpc, ptx, sparc, spu, x86, x86_64, xcore</tt>.
<br><br></dd>
<dt><i>--enable-doxygen</i></dt>
<dd>Look for the doxygen program and enable construction of doxygen based
documentation from the source code. This is disabled by default because
generating the documentation can take a long time and producess 100s of
megabytes of output.</dd>
<dt><i>--with-udis86</i></dt>
<dd>LLVM can use external disassembler library for various purposes (now it's
used only for examining code produced by JIT). This option will enable usage
of <a href="http://udis86.sourceforge.net/">udis86</a> x86 (both 32 and 64
bits) disassembler library.</dd>
</dl>
<p>To configure LLVM, follow these steps:</p>
<ol>
<li><p>Change directory into the object root directory:</p>
<div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
<li><p>Run the <tt>configure</tt> script located in the LLVM source
tree:</p>
<div class="doc_code">
<pre>% <i>SRC_ROOT</i>/configure --prefix=/install/path [other options]</pre>
</div></li>
</ol>
</div>
<!-- ======================================================================= -->
<h3>
<a name="compile">Compiling the LLVM Suite Source Code</a>
</h3>
<div>
<p>Once you have configured LLVM, you can build it. There are three types of
builds:</p>
<dl>
<dt>Debug Builds
<dd>
These builds are the default when one is using an Subversion checkout and
types <tt>gmake</tt> (unless the <tt>--enable-optimized</tt> option was
used during configuration). The build system will compile the tools and
libraries with debugging information. To get a Debug Build using the
LLVM distribution the <tt>--disable-optimized</tt> option must be passed
to <tt>configure</tt>.
<br><br>
<dt>Release (Optimized) Builds
<dd>
These builds are enabled with the <tt>--enable-optimized</tt> option to
<tt>configure</tt> or by specifying <tt>ENABLE_OPTIMIZED=1</tt> on the
<tt>gmake</tt> command line. For these builds, the build system will
compile the tools and libraries with GCC optimizations enabled and strip
debugging information from the libraries and executables it generates.
Note that Release Builds are default when using an LLVM distribution.
<br><br>
<dt>Profile Builds
<dd>
These builds are for use with profiling. They compile profiling
information into the code for use with programs like <tt>gprof</tt>.
Profile builds must be started by specifying <tt>ENABLE_PROFILING=1</tt>
on the <tt>gmake</tt> command line.
</dl>
<p>Once you have LLVM configured, you can build it by entering the
<i>OBJ_ROOT</i> directory and issuing the following command:</p>
<div class="doc_code"><pre>% gmake</pre></div>
<p>If the build fails, please <a href="#brokengcc">check here</a> to see if you
are using a version of GCC that is known not to compile LLVM.</p>
<p>
If you have multiple processors in your machine, you may wish to use some of
the parallel build options provided by GNU Make. For example, you could use the
command:</p>
<div class="doc_code"><pre>% gmake -j2</pre></div>
<p>There are several special targets which are useful when working with the LLVM
source code:</p>
<dl>
<dt><tt>gmake clean</tt>
<dd>
Removes all files generated by the build. This includes object files,
generated C/C++ files, libraries, and executables.
<br><br>
<dt><tt>gmake dist-clean</tt>
<dd>
Removes everything that <tt>gmake clean</tt> does, but also removes files
generated by <tt>configure</tt>. It attempts to return the source tree to the
original state in which it was shipped.
<br><br>
<dt><tt>gmake install</tt>
<dd>
Installs LLVM header files, libraries, tools, and documentation in a
hierarchy
under $PREFIX, specified with <tt>./configure --prefix=[dir]</tt>, which
defaults to <tt>/usr/local</tt>.
<br><br>
<dt><tt>gmake -C runtime install-bytecode</tt>
<dd>
Assuming you built LLVM into $OBJDIR, when this command is run, it will
install bitcode libraries into the GCC front end's bitcode library
directory. If you need to update your bitcode libraries,
this is the target to use once you've built them.
<br><br>
</dl>
<p>Please see the <a href="MakefileGuide.html">Makefile Guide</a> for further
details on these <tt>make</tt> targets and descriptions of other targets
available.</p>
<p>It is also possible to override default values from <tt>configure</tt> by
declaring variables on the command line. The following are some examples:</p>
<dl>
<dt><tt>gmake ENABLE_OPTIMIZED=1</tt>
<dd>
Perform a Release (Optimized) build.
<br><br>
<dt><tt>gmake ENABLE_OPTIMIZED=1 DISABLE_ASSERTIONS=1</tt>
<dd>
Perform a Release (Optimized) build without assertions enabled.
<br><br>
<dt><tt>gmake ENABLE_OPTIMIZED=0</tt>
<dd>
Perform a Debug build.
<br><br>
<dt><tt>gmake ENABLE_PROFILING=1</tt>
<dd>
Perform a Profiling build.
<br><br>
<dt><tt>gmake VERBOSE=1</tt>
<dd>
Print what <tt>gmake</tt> is doing on standard output.
<br><br>
<dt><tt>gmake TOOL_VERBOSE=1</tt></dt>
<dd>Ask each tool invoked by the makefiles to print out what it is doing on
the standard output. This also implies <tt>VERBOSE=1</tt>.
<br><br></dd>
</dl>
<p>Every directory in the LLVM object tree includes a <tt>Makefile</tt> to build
it and any subdirectories that it contains. Entering any directory inside the
LLVM object tree and typing <tt>gmake</tt> should rebuild anything in or below
that directory that is out of date.</p>
</div>
<!-- ======================================================================= -->
<h3>
<a name="cross-compile">Cross-Compiling LLVM</a>
</h3>
<div>
<p>It is possible to cross-compile LLVM itself. That is, you can create LLVM
executables and libraries to be hosted on a platform different from the
platform where they are build (a Canadian Cross build). To configure a
cross-compile, supply the configure script with <tt>--build</tt> and
<tt>--host</tt> options that are different. The values of these options must
be legal target triples that your GCC compiler supports.</p>
<p>The result of such a build is executables that are not runnable on
on the build host (--build option) but can be executed on the compile host
(--host option).</p>
</div>
<!-- ======================================================================= -->
<h3>
<a name="objfiles">The Location of LLVM Object Files</a>
</h3>
<div>
<p>The LLVM build system is capable of sharing a single LLVM source tree among
several LLVM builds. Hence, it is possible to build LLVM for several different
platforms or configurations using the same source tree.</p>
<p>This is accomplished in the typical autoconf manner:</p>
<ul>
<li><p>Change directory to where the LLVM object files should live:</p>
<div class="doc_code"><pre>% cd <i>OBJ_ROOT</i></pre></div></li>
<li><p>Run the <tt>configure</tt> script found in the LLVM source
directory:</p>
<div class="doc_code"><pre>% <i>SRC_ROOT</i>/configure</pre></div></li>
</ul>
<p>The LLVM build will place files underneath <i>OBJ_ROOT</i> in directories
named after the build type:</p>
<dl>
<dt>Debug Builds with assertions enabled (the default)
<dd>
<dl>
<dt>Tools
<dd><tt><i>OBJ_ROOT</i>/Debug+Asserts/bin</tt>
<dt>Libraries
<dd><tt><i>OBJ_ROOT</i>/Debug+Asserts/lib</tt>
</dl>
<br><br>
<dt>Release Builds
<dd>
<dl>
<dt>Tools
<dd><tt><i>OBJ_ROOT</i>/Release/bin</tt>
<dt>Libraries
<dd><tt><i>OBJ_ROOT</i>/Release/lib</tt>
</dl>
<br><br>
<dt>Profile Builds
<dd>
<dl>
<dt>Tools
<dd><tt><i>OBJ_ROOT</i>/Profile/bin</tt>
<dt>Libraries
<dd><tt><i>OBJ_ROOT</i>/Profile/lib</tt>
</dl>
</dl>
</div>
<!-- ======================================================================= -->
<h3>
<a name="optionalconfig">Optional Configuration Items</a>
</h3>
<div>
<p>
If you're running on a Linux system that supports the "<a
href="http://www.tat.physik.uni-tuebingen.de/~rguenth/linux/binfmt_misc.html">binfmt_misc</a>"
module, and you have root access on the system, you can set your system up to
execute LLVM bitcode files directly. To do this, use commands like this (the
first command may not be required if you are already using the module):</p>
<div class="doc_code">
<pre>
$ mount -t binfmt_misc none /proc/sys/fs/binfmt_misc
$ echo ':llvm:M::BC::/path/to/lli:' > /proc/sys/fs/binfmt_misc/register
$ chmod u+x hello.bc (if needed)
$ ./hello.bc
</pre>
</div>
<p>
This allows you to execute LLVM bitcode files directly. On Debian, you
can also use this command instead of the 'echo' command above:
</p>
<div class="doc_code">
<pre>
$ sudo update-binfmts --install llvm /path/to/lli --magic 'BC'
</pre>
</div>
</div>
</div>
<!-- *********************************************************************** -->
<h2>
<a name="layout">Program Layout</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p>One useful source of information about the LLVM source base is the LLVM <a
href="http://www.doxygen.org/">doxygen</a> documentation available at <tt><a
href="http://llvm.org/doxygen/">http://llvm.org/doxygen/</a></tt>.
The following is a brief introduction to code layout:</p>
<!-- ======================================================================= -->
<h3>
<a name="examples"><tt>llvm/examples</tt></a>
</h3>
<div>
<p>This directory contains some simple examples of how to use the LLVM IR and
JIT.</p>
</div>
<!-- ======================================================================= -->
<h3>
<a name="include"><tt>llvm/include</tt></a>
</h3>
<div>
<p>This directory contains public header files exported from the LLVM
library. The three main subdirectories of this directory are:</p>
<dl>
<dt><tt><b>llvm/include/llvm</b></tt></dt>
<dd>This directory contains all of the LLVM specific header files. This
directory also has subdirectories for different portions of LLVM:
<tt>Analysis</tt>, <tt>CodeGen</tt>, <tt>Target</tt>, <tt>Transforms</tt>,
etc...</dd>
<dt><tt><b>llvm/include/llvm/Support</b></tt></dt>
<dd>This directory contains generic support libraries that are provided with
LLVM but not necessarily specific to LLVM. For example, some C++ STL utilities
and a Command Line option processing library store their header files here.
</dd>
<dt><tt><b>llvm/include/llvm/Config</b></tt></dt>
<dd>This directory contains header files configured by the <tt>configure</tt>
script. They wrap "standard" UNIX and C header files. Source code can
include these header files which automatically take care of the conditional
#includes that the <tt>configure</tt> script generates.</dd>
</dl>
</div>
<!-- ======================================================================= -->
<h3>
<a name="lib"><tt>llvm/lib</tt></a>
</h3>
<div>
<p>This directory contains most of the source files of the LLVM system. In LLVM,
almost all code exists in libraries, making it very easy to share code among the
different <a href="#tools">tools</a>.</p>
<dl>
<dt><tt><b>llvm/lib/VMCore/</b></tt></dt>
<dd> This directory holds the core LLVM source files that implement core
classes like Instruction and BasicBlock.</dd>
<dt><tt><b>llvm/lib/AsmParser/</b></tt></dt>
<dd>This directory holds the source code for the LLVM assembly language parser
library.</dd>
<dt><tt><b>llvm/lib/BitCode/</b></tt></dt>
<dd>This directory holds code for reading and write LLVM bitcode.</dd>
<dt><tt><b>llvm/lib/Analysis/</b></tt><dd>This directory contains a variety of
different program analyses, such as Dominator Information, Call Graphs,
Induction Variables, Interval Identification, Natural Loop Identification,
etc.</dd>
<dt><tt><b>llvm/lib/Transforms/</b></tt></dt>
<dd> This directory contains the source code for the LLVM to LLVM program
transformations, such as Aggressive Dead Code Elimination, Sparse Conditional
Constant Propagation, Inlining, Loop Invariant Code Motion, Dead Global
Elimination, and many others.</dd>
<dt><tt><b>llvm/lib/Target/</b></tt></dt>
<dd> This directory contains files that describe various target architectures
for code generation. For example, the <tt>llvm/lib/Target/X86</tt>
directory holds the X86 machine description while
<tt>llvm/lib/Target/ARM</tt> implements the ARM backend.</dd>
<dt><tt><b>llvm/lib/CodeGen/</b></tt></dt>
<dd> This directory contains the major parts of the code generator: Instruction
Selector, Instruction Scheduling, and Register Allocation.</dd>
<dt><tt><b>llvm/lib/MC/</b></tt></dt>
<dd>(FIXME: T.B.D.)</dd>
<!--FIXME: obsoleted -->
<dt><tt><b>llvm/lib/Debugger/</b></tt></dt>
<dd> This directory contains the source level debugger library that makes
it possible to instrument LLVM programs so that a debugger could identify
source code locations at which the program is executing.</dd>
<dt><tt><b>llvm/lib/ExecutionEngine/</b></tt></dt>
<dd> This directory contains libraries for executing LLVM bitcode directly
at runtime in both interpreted and JIT compiled fashions.</dd>
<dt><tt><b>llvm/lib/Support/</b></tt></dt>
<dd> This directory contains the source code that corresponds to the header
files located in <tt>llvm/include/ADT/</tt>
and <tt>llvm/include/Support/</tt>.</dd>
</dl>
</div>
<!-- ======================================================================= -->
<h3>
<a name="projects"><tt>llvm/projects</tt></a>
</h3>
<div>
<p>This directory contains projects that are not strictly part of LLVM but are
shipped with LLVM. This is also the directory where you should create your own
LLVM-based projects. See <tt>llvm/projects/sample</tt> for an example of how
to set up your own project.</p>
</div>
<!-- ======================================================================= -->
<h3>
<a name="runtime"><tt>llvm/runtime</tt></a>
</h3>
<div>
<p>This directory contains libraries which are compiled into LLVM bitcode and
used when linking programs with the Clang front end. Most of these libraries are
skeleton versions of real libraries; for example, libc is a stripped down
version of glibc.</p>
<p>Unlike the rest of the LLVM suite, this directory needs the LLVM GCC front
end to compile.</p>
</div>
<!-- ======================================================================= -->
<h3>
<a name="test"><tt>llvm/test</tt></a>
</h3>
<div>
<p>This directory contains feature and regression tests and other basic sanity
checks on the LLVM infrastructure. These are intended to run quickly and cover
a lot of territory without being exhaustive.</p>
</div>
<!-- ======================================================================= -->
<h3>
<a name="test-suite"><tt>test-suite</tt></a>
</h3>
<div>
<p>This is not a directory in the normal llvm module; it is a separate
Subversion
module that must be checked out (usually to <tt>projects/test-suite</tt>).
This
module contains a comprehensive correctness, performance, and benchmarking
test
suite for LLVM. It is a separate Subversion module because not every LLVM
user is
interested in downloading or building such a comprehensive test suite. For
further details on this test suite, please see the
<a href="TestingGuide.html">Testing Guide</a> document.</p>
</div>
<!-- ======================================================================= -->
<h3>
<a name="tools"><tt>llvm/tools</tt></a>
</h3>
<div>
<p>The <b>tools</b> directory contains the executables built out of the
libraries above, which form the main part of the user interface. You can
always get help for a tool by typing <tt>tool_name -help</tt>. The
following is a brief introduction to the most important tools. More detailed
information is in the <a href="CommandGuide/index.html">Command Guide</a>.</p>
<dl>
<dt><tt><b>bugpoint</b></tt></dt>
<dd><tt>bugpoint</tt> is used to debug
optimization passes or code generation backends by narrowing down the
given test case to the minimum number of passes and/or instructions that
still cause a problem, whether it is a crash or miscompilation. See <a
href="HowToSubmitABug.html">HowToSubmitABug.html</a> for more information
on using <tt>bugpoint</tt>.</dd>
<dt><tt><b>llvm-ar</b></tt></dt>
<dd>The archiver produces an archive containing
the given LLVM bitcode files, optionally with an index for faster
lookup.</dd>
<dt><tt><b>llvm-as</b></tt></dt>
<dd>The assembler transforms the human readable LLVM assembly to LLVM
bitcode.</dd>
<dt><tt><b>llvm-dis</b></tt></dt>
<dd>The disassembler transforms the LLVM bitcode to human readable
LLVM assembly.</dd>
<dt><tt><b>llvm-link</b></tt></dt>
<dd><tt>llvm-link</tt>, not surprisingly, links multiple LLVM modules into
a single program.</dd>
<dt><tt><b>lli</b></tt></dt>
<dd><tt>lli</tt> is the LLVM interpreter, which
can directly execute LLVM bitcode (although very slowly...). For architectures
that support it (currently x86, Sparc, and PowerPC), by default, <tt>lli</tt>
will function as a Just-In-Time compiler (if the functionality was compiled
in), and will execute the code <i>much</i> faster than the interpreter.</dd>
<dt><tt><b>llc</b></tt></dt>
<dd> <tt>llc</tt> is the LLVM backend compiler, which
translates LLVM bitcode to a native code assembly file or to C code (with
the -march=c option).</dd>
<dt><tt><b>llvm-gcc</b></tt></dt>
<dd><tt>llvm-gcc</tt> is a GCC-based C frontend that has been retargeted to
use LLVM as its backend instead of GCC's RTL backend. It can also emit LLVM
bitcode or assembly (with the <tt>-emit-llvm</tt> option) instead of the
usual machine code output. It works just like any other GCC compiler,
taking the typical <tt>-c, -S, -E, -o</tt> options that are typically used.
Additionally, the source code for <tt>llvm-gcc</tt> is available as a
separate Subversion module.</dd>
<dt><tt><b>opt</b></tt></dt>
<dd><tt>opt</tt> reads LLVM bitcode, applies a series of LLVM to LLVM
transformations (which are specified on the command line), and then outputs
the resultant bitcode. The '<tt>opt -help</tt>' command is a good way to
get a list of the program transformations available in LLVM.<br>
<dd><tt>opt</tt> can also be used to run a specific analysis on an input
LLVM bitcode file and print out the results. It is primarily useful for
debugging analyses, or familiarizing yourself with what an analysis does.</dd>
</dl>
</div>
<!-- ======================================================================= -->
<h3>
<a name="utils"><tt>llvm/utils</tt></a>
</h3>
<div>
<p>This directory contains utilities for working with LLVM source code, and some
of the utilities are actually required as part of the build process because they
are code generators for parts of LLVM infrastructure.</p>
<dl>
<dt><tt><b>codegen-diff</b></tt> <dd><tt>codegen-diff</tt> is a script
that finds differences between code that LLC generates and code that LLI
generates. This is a useful tool if you are debugging one of them,
assuming that the other generates correct output. For the full user
manual, run <tt>`perldoc codegen-diff'</tt>.<br><br>
<dt><tt><b>emacs/</b></tt> <dd>The <tt>emacs</tt> directory contains
syntax-highlighting files which will work with Emacs and XEmacs editors,
providing syntax highlighting support for LLVM assembly files and TableGen
description files. For information on how to use the syntax files, consult
the <tt>README</tt> file in that directory.<br><br>
<dt><tt><b>getsrcs.sh</b></tt> <dd>The <tt>getsrcs.sh</tt> script finds
and outputs all non-generated source files, which is useful if one wishes
to do a lot of development across directories and does not want to
individually find each file. One way to use it is to run, for example:
<tt>xemacs `utils/getsources.sh`</tt> from the top of your LLVM source
tree.<br><br>
<dt><tt><b>llvmgrep</b></tt></dt>
<dd>This little tool performs an "egrep -H -n" on each source file in LLVM and
passes to it a regular expression provided on <tt>llvmgrep</tt>'s command
line. This is a very efficient way of searching the source base for a
particular regular expression.</dd>
<dt><tt><b>makellvm</b></tt> <dd>The <tt>makellvm</tt> script compiles all
files in the current directory and then compiles and links the tool that
is the first argument. For example, assuming you are in the directory
<tt>llvm/lib/Target/Sparc</tt>, if <tt>makellvm</tt> is in your path,
simply running <tt>makellvm llc</tt> will make a build of the current
directory, switch to directory <tt>llvm/tools/llc</tt> and build it,
causing a re-linking of LLC.<br><br>
<dt><tt><b>TableGen/</b></tt> <dd>The <tt>TableGen</tt> directory contains
the tool used to generate register descriptions, instruction set
descriptions, and even assemblers from common TableGen description
files.<br><br>
<dt><tt><b>vim/</b></tt> <dd>The <tt>vim</tt> directory contains
syntax-highlighting files which will work with the VIM editor, providing
syntax highlighting support for LLVM assembly files and TableGen
description files. For information on how to use the syntax files, consult
the <tt>README</tt> file in that directory.<br><br>
</dl>
</div>
</div>
<!-- *********************************************************************** -->
<h2>
<a name="tutorial">An Example Using the LLVM Tool Chain</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p>This section gives an example of using LLVM with the Clang front end.</p>
<!-- ======================================================================= -->
<h3>
<a name="tutorial4">Example with clang</a>
</h3>
<div>
<ol>
<li><p>First, create a simple C file, name it 'hello.c':</p>
<div class="doc_code">
<pre>
#include <stdio.h>
int main() {
printf("hello world\n");
return 0;
}
</pre></div></li>
<li><p>Next, compile the C file into a native executable:</p>
<div class="doc_code"><pre>% clang hello.c -o hello</pre></div>
<p>Note that clang works just like GCC by default. The standard -S and
-c arguments work as usual (producing a native .s or .o file,
respectively).</p></li>
<li><p>Next, compile the C file into a LLVM bitcode file:</p>
<div class="doc_code">
<pre>% clang -O3 -emit-llvm hello.c -c -o hello.bc</pre></div>
<p>The -emit-llvm option can be used with the -S or -c options to emit an
LLVM ".ll" or ".bc" file (respectively) for the code. This allows you
to use the <a href="CommandGuide/index.html">standard LLVM tools</a> on
the bitcode file.</p></li>
<li><p>Run the program in both forms. To run the program, use:</p>
<div class="doc_code"><pre>% ./hello</pre></div>
<p>and</p>
<div class="doc_code"><pre>% lli hello.bc</pre></div>
<p>The second examples shows how to invoke the LLVM JIT, <a
href="CommandGuide/html/lli.html">lli</a>.</p></li>
<li><p>Use the <tt>llvm-dis</tt> utility to take a look at the LLVM assembly
code:</p>
<div class="doc_code">
<pre>llvm-dis < hello.bc | less</pre>
</div></li>
<li><p>Compile the program to native assembly using the LLC code
generator:</p>
<div class="doc_code"><pre>% llc hello.bc -o hello.s</pre></div></li>
<li><p>Assemble the native assembly language file into a program:</p>
<div class="doc_code">
<pre>
<b>Solaris:</b> % /opt/SUNWspro/bin/cc -xarch=v9 hello.s -o hello.native
<b>Others:</b> % gcc hello.s -o hello.native
</pre>
</div></li>
<li><p>Execute the native code program:</p>
<div class="doc_code"><pre>% ./hello.native</pre></div>
<p>Note that using clang to compile directly to native code (i.e. when
the -emit-llvm option is not present) does steps 6/7/8 for you.</p>
</li>
</ol>
</div>
</div>
<!-- *********************************************************************** -->
<h2>
<a name="problems">Common Problems</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p>If you are having problems building or using LLVM, or if you have any other
general questions about LLVM, please consult the <a href="FAQ.html">Frequently
Asked Questions</a> page.</p>
</div>
<!-- *********************************************************************** -->
<h2>
<a name="links">Links</a>
</h2>
<!-- *********************************************************************** -->
<div>
<p>This document is just an <b>introduction</b> on how to use LLVM to do
some simple things... there are many more interesting and complicated things
that you can do that aren't documented here (but we'll gladly accept a patch
if you want to write something up!). For more information about LLVM, check
out:</p>
<ul>
<li><a href="http://llvm.org/">LLVM homepage</a></li>
<li><a href="http://llvm.org/doxygen/">LLVM doxygen tree</a></li>
<li><a href="http://llvm.org/docs/Projects.html">Starting a Project
that Uses LLVM</a></li>
</ul>
</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:sabre@nondot.org">Chris Lattner</a><br>
<a href="http://llvm.x10sys.com/rspencer/">Reid Spencer</a><br>
<a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Last modified: $Date$
</address>
</body>
</html>
|
