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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 77d29b1f6245f401a39aadacebc2af951a32589a / . / docs / ReleaseNotes.html
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Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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3<html>
4<head>
Reid Spencer6454ed32004-11-18 18:38:58 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]6 <link rel="stylesheet" href="llvm.css" type="text/css">
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]7 <title>LLVM 2.3 Release Notes</title>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]8</head>
9<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]10
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]11<div class="doc_title">LLVM 2.3 Release Notes</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]12
13<ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]14 <li><a href="#intro">Introduction</a></li>
15 <li><a href="#whatsnew">What's New?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +0000[diff] [blame]16 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]18 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]19 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]20</ol>
21
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]22<div class="doc_author">
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]23 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]24</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]25
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame^]26<!-- Done through Week-of-Mon-20080324.txt -->
27
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]28<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]29<div class="doc_section">
30 <a name="intro">Introduction</a>
31</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]32<!-- *********************************************************************** -->
33
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]34<div class="doc_text">
35
36<p>This document contains the release notes for the LLVM compiler
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]37infrastructure, release 2.3. Here we describe the status of LLVM, including
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]38major improvements from the previous release and any known problems. All LLVM
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]39releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]40releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]41
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]42<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]43release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]44web site</a>. If you have questions or comments, the <a
45href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]46list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]47
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]48<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]49main LLVM web page, this document applies to the <i>next</i> release, not the
50current one. To see the release notes for a specific releases, please see the
51<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]52
53</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]54
55<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]56<div class="doc_section">
57 <a name="whatsnew">What's New?</a>
58</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]59<!-- *********************************************************************** -->
60
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]61<div class="doc_text">
62
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]63<p>This is the fourteenth public release of the LLVM Compiler Infrastructure.
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]64It includes a large number of features and refinements from LLVM 2.2.</p>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]65
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]66</div>
67
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]68<!-- Unfinished features in 2.3:
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]69 Machine LICM
70 Machine Sinking
71 LegalizeDAGTypes
72 -->
73
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]74<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]75<div class="doc_subsection">
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame^]76<a name="changes">Major Changes in LLVM 2.3</a>
Chris Lattnerb4c68cd2008-02-10 07:04:35 +0000[diff] [blame]77</div>
78
79<div class="doc_text">
80
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]81<p>LLVM 2.2 was the last LLVM release to support llvm-gcc 4.0 and llvm-upgrade.
82llvm-gcc 4.0 has been replaced with llvm-gcc 4.2. llvm-upgrade was useful for
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]83upgrading LLVM 1.9 files to LLVM 2.x syntax, but you can always use a previous
84LLVM release to do this. One nice impact of this is that the LLVM regressionn
85test suite no longer depends on llvm-upgrade, which makes it run faster.</p>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]86
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame^]87<p>LLVM 2.3 renames the LLVMBuilder and LLVMFoldingBuilder classes to
88 IRBuilder.</p>
89
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]90</div>
91
92<!--=========================================================================-->
93<div class="doc_subsection">
94<a name="majorfeatures">Major New Features</a>
95</div>
96
97<div class="doc_text">
98
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]99<p>LLVM 2.3 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]100
101<ul>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]102<li>Multiple Return Value Support</li>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]103
104
105<li><p>LLVM 2.3 includes a complete reimplementation of the "llvmc" tool. It is
106designed to overcome several problems of the original llvmc and to provide a
107superset of the features as the 'gcc' driver.</p>
108
109<p>The main features of llvmc2 is:</p>
110
111<ul>
112<li>Extended handling of command line options and smart rules for
113dispatching them to different tools.</li>
114<li>Flexible (and extensible) rules for defining different tools.</li>
115<li>The different intermediate steps performed by tools are represented
116as edged in the abstract graph.</li>
117</l>The 'language' for driver behaviour definition is tablegen and thus
118it's relatively easy to add new features.</li>
119<li>The definition of driver is transformed into set of C++ classes, thus
120no runtime interpretation is needed.</li>
121</ul>
122
123</li>
124
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame^]125<li>Reimplemented <a href="LinkTimeOptimization.html">LTO interface</a> in
126 C.</li>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]127
128
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame^]129<li>kaleidoscope tutorial in ocaml.</li>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]130
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]131</ul>
132
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]133</div>
134
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]135
136<!--=========================================================================-->
137<div class="doc_subsection">
138<a name="frontends">llvm-gcc 4.2 Improvements and Clang</a>
139</div>
140
141<div class="doc_text">
142
143<p>LLVM 2.3 fully supports llvm-gcc 4.2 front-end.</p>
144
145<p>llvm-gcc 4.2 includes numerous fixes to better support the Objective-C
146front-end. Objective-C now works very well on Mac OS/X.</p>
147
148<p>llvm-gcc 4.2 includes many other fixes which improve conformance with the
149relevant parts of the GCC testsuite.</p>
150
151<p>The <a href="http://clang.llvm.org/">clang project</a> is an effort to build
152a set of new 'llvm native' front-end technologies for the LLVM optimizer
153and code generator. Currently, its C and Objective-C support is maturing
154nicely, and it has advanced source-to-source analysis and transformation
155capabilities. If you are interested in building source-level tools for C and
156Objective-C (and eventually C++), you should take a look. However, note that
157clang is not an official part of the LLVM 2.3 release. If you are interested in
158this project, please see its <a href="http://clang.llvm.org/">web site</a>.</p>
159
160</div>
161
162
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]163<!--=========================================================================-->
164<div class="doc_subsection">
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]165<a name="coreimprovements">LLVM Core Improvements</a>
166</div>
167
168<div class="doc_text">
169<p>New features include:
170</p>
171
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]172
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]173Common linkage?
174
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame^]175Atomic operation support, Alpha, X86, X86-64, PowerPC. "__sync_synchronize"
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]176
177<ul>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]178</ul>
179
180</div>
181
182<!--=========================================================================-->
183<div class="doc_subsection">
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]184<a name="codegen">Code Generator Improvements</a>
185</div>
186
187<div class="doc_text">
188
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]189<p>We put a significant amount of work into the code generator infrastructure,
190which allows us to implement more aggressive algorithms and make it run
191faster:</p>
Chris Lattnerd4298712007-09-26 05:44:21 +0000[diff] [blame]192
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]193<ul>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]194<li>MemOperand in the code generator: describe me!.</li>
195<li>i128 support and APInt through most of codegen.</li>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame^]196<li>Several compile time speedups for code with large basic blocks.</li>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]197</ul>
198
199</div>
200
201<!--=========================================================================-->
202<div class="doc_subsection">
203<a name="optimizer">Optimizer Improvements</a>
204</div>
205
206<div class="doc_text">
207
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]208<p>In addition to a huge array of bug fixes and minor performance tweaks, the
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]209LLVM 2.3 optimizers support a few major enhancements:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]210
211<ul>
212
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]213<li>Loop index set splitting on by default: describe me.</li>
214<li>LLVM includes a new memcpy optimization pass which optimizes out dead
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame^]215memcpy calls, unneeded copies of aggregates, and handles the return slot
216optimization. The LLVM optimizer now notices long sequences of consequtive
217stores and merges them into memcpy's where profitable.</li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]218</ul>
219
220</div>
221
222
223<!--=========================================================================-->
224<div class="doc_subsection">
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame^]225<a name="x86specific">X86/X86-64 Specific Improvements</a>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]226</div>
Chris Lattner60893e52007-05-18 06:33:02 +0000[diff] [blame]227
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]228<div class="doc_text">
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]229<p>New target-specific features include:
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]230</p>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]231
232<ul>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]233<li>llvm-gcc's X86-64 ABI conformance is far improved, particularly in the
234 area of passing and returning structures by value. llvm-gcc Compiled code
235 now interoperates very well on X86-64 systems with other compilers.</li>
236
237<li>The LLVM X86 backend now supports the support SSE 4.1 instruction set, and
238 the llvm-gcc 4.2 front-end supports the SSE 4.1 compiler builtins.</li>
239
240<li>The X86 backend now does a number of optimizations that aim to avoid
241 converting numbers back and forth from SSE registers to the X87 floating
242 point stack.</li>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]243
244<li>The X86 backend supports stack realignment, which is particularly useful for
245 vector code on OS's without 16-byte aligned stacks.</li>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]246
247<li>The X86 backend now supports the "sseregparm" options in GCC, which allow
248 functions to be tagged as passing floating point values in SSE
249 registers.</li>
250
251<li>Trampolines (taking the address of a nested function) now work on
252 Linux/x86-64.</li>
253
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame^]254<li><tt>__builtin_prefetch</tt> is now compiled into the appropriate prefetch
255 instructions instead of being ignored.</li>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]256
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000[diff] [blame]257</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]258
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000[diff] [blame]259</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]260
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]261<!--=========================================================================-->
262<div class="doc_subsection">
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame^]263<a name="targetspecific">Other Target Specific Improvements</a>
264</div>
265
266<div class="doc_text">
267<p>New target-specific features include:
268</p>
269
270<ul>
271<li>The LLVM C backend now supports vectors code.</li>
272
273
274</ul>
275
276</div>
277
278
279
280<!--=========================================================================-->
281<div class="doc_subsection">
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]282<a name="otherimprovements">Other Improvements</a>
283</div>
284
285<div class="doc_text">
286<p>New features include:
287</p>
288
289<ul>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]290<li>LLVM now builds with GCC 4.3.</li>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame^]291<li>llvm2cpp tool was moved into llc, use llc -march=cpp</li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]292</ul>
293
294</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]295
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]296<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]297<div class="doc_section">
298 <a name="portability">Portability and Supported Platforms</a>
299</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]300<!-- *********************************************************************** -->
301
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]302<div class="doc_text">
303
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]304<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]305
306<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]307<li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
Reid Spencer00812e22005-05-17 02:47:27 +0000[diff] [blame]308 (and probably other unix-like systems).</li>
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]309<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit and
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]310 64-bit modes.</li>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]311<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]312<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
313 support is available for native builds with Visual C++).</li>
314<li>Sun UltraSPARC workstations running Solaris 8.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]315<li>Alpha-based machines running Debian GNU/Linux.</li>
316<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]317</ul>
318
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]319<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]320to the machine and operating system on which it is built. However, minor
321porting may be required to get LLVM to work on new platforms. We welcome your
322portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]323
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]324</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]325
326<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]327<div class="doc_section">
328 <a name="knownproblems">Known Problems</a>
329</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]330<!-- *********************************************************************** -->
331
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]332<div class="doc_text">
333
334<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]335component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]336sections. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]337href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]338there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]339
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]340</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]341
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]342<!-- ======================================================================= -->
343<div class="doc_subsection">
344 <a name="experimental">Experimental features included with this release</a>
345</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]346
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]347<div class="doc_text">
348
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]349<p>The following components of this LLVM release are either untested, known to
350be broken or unreliable, or are in early development. These components should
351not be relied on, and bugs should not be filed against them, but they may be
352useful to some people. In particular, if you would like to work on one of these
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]353components, please contact us on the <a
354href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]355
356<ul>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]357<li>The MSIL, IA64, Alpha, SPU, and MIPS backends are experimental.</li>
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]358<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
359 value for this option.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]360</ul>
361
362</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]363
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]364<!-- ======================================================================= -->
365<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]366 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]367</div>
368
369<div class="doc_text">
370
371<ul>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame^]372<li>The X86 backend does not yet support all <a
373 href="http://llvm.org/PR879">inline assembly that uses the X86 floating
374 point stack</a>. It supports the 'f' and 't' constraints, but not 'u'.</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]375<li>The X86 backend generates inefficient floating point code when configured to
376 generate code for systems that don't have SSE2.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]377</ul>
378
379</div>
380
381<!-- ======================================================================= -->
382<div class="doc_subsection">
383 <a name="ppc-be">Known problems with the PowerPC back-end</a>
384</div>
385
386<div class="doc_text">
387
388<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000[diff] [blame]389<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]390compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]391</ul>
392
393</div>
394
395<!-- ======================================================================= -->
396<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]397 <a name="arm-be">Known problems with the ARM back-end</a>
398</div>
399
400<div class="doc_text">
401
402<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]403<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000[diff] [blame]404processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]405results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]406<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
407</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]408<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly execute
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]409programs compiled with LLVM. Please use more recent versions of QEMU.</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]410</ul>
411
412</div>
413
414<!-- ======================================================================= -->
415<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]416 <a name="sparc-be">Known problems with the SPARC back-end</a>
417</div>
418
419<div class="doc_text">
420
421<ul>
422<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
423 support the 64-bit SPARC ABI (-m64).</li>
424</ul>
425
426</div>
427
428<!-- ======================================================================= -->
429<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]430 <a name="alpha-be">Known problems with the Alpha back-end</a>
431</div>
432
433<div class="doc_text">
434
435<ul>
436
437<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
438appropriate nops inserted to ensure restartability.</li>
439
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]440</ul>
441</div>
442
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]443<!-- ======================================================================= -->
444<div class="doc_subsection">
445 <a name="ia64-be">Known problems with the IA64 back-end</a>
446</div>
447
448<div class="doc_text">
449
450<ul>
451
452<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
453made where the argument is not 16-byte aligned, as required on IA64. (Strictly
454speaking this is not a bug in the IA64 back-end; it will also be encountered
455when building C++ programs using the C back-end.)</li>
456
457<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
458ABI compliant layout of v-tables</a>. In particular, it just stores function
459pointers instead of function descriptors in the vtable. This bug prevents
460mixing C++ code compiled with LLVM with C++ objects compiled by other C++
461compilers.</li>
462
463<li>There are a few ABI violations which will lead to problems when mixing LLVM
464output with code built with other compilers, particularly for floating-point
465programs.</li>
466
467<li>Defining vararg functions is not supported (but calling them is ok).</li>
468
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]469<li>The Itanium backend has bitrotted somewhat.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]470</ul>
471
472</div>
473
474<!-- ======================================================================= -->
475<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]476 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]477</div>
478
479<div class="doc_text">
480
481<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]482<li><a href="http://llvm.org/PR802">The C backend has only basic support for
483 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000[diff] [blame]484<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
485 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
486 C++ code compiled with LLC or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]487<li>The C backend does not support all exception handling constructs.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]488</ul>
489
490</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]491
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]492
493<!-- ======================================================================= -->
494<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]495 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]496</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]497
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]498<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]499<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]500
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]501<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]502
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]503<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
504Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]505llvmdev mailing list if you are interested.</p>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]506
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]507<p>The only major language feature of GCC not supported by llvm-gcc is
508 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
509 are only supported on some targets. For example, trampolines are only
510 supported on some targets, which are used when you take the address of a
511 nested function.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]512
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]513<p>If you run into GCC extensions which are not supported, please let us know.
514</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]515
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]516</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]517
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]518<!-- ======================================================================= -->
519<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]520 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]521</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]522
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]523<div class="doc_text">
524
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]525<p>The C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]526tested and works for a number of non-trivial programs, including LLVM
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]527itself, Qt, Mozilla, etc.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]528
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]529<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]530<li>Exception handling works well on the X86 and PowerPC targets, including
531x86-64 darwin. This works when linking to a libstdc++ compiled by GCC. It is
532supported on x86-64 linux, but that is disabled by default in this release.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]533</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]534
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]535</div>
536
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]537
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]538<!-- ======================================================================= -->
539<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]540 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]541</div>
542
543<div class="doc_text">
544The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
545technology and problems should be expected.
546<ul>
547<li>The Ada front-end currently only builds on x86-32. This is mainly due
548to lack of trampoline support (pointers to nested functions) on other platforms,
549however it <a href="http://llvm.org/PR2006">also fails to build on x86-64</a>
550which does support trampolines.</li>
551<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
552Workaround: configure with --disable-bootstrap.</li>
553<li>The c380004 and <a href="http://llvm.org/PR2010">c393010</a> ACATS tests
554fail (c380004 also fails with gcc-4.2 mainline).</li>
555<li>Many gcc specific Ada tests continue to crash the compiler.</li>
556<li>The -E binder option (exception backtraces)
557<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
558crashing if an exception is raised. Workaround: do not use -E.</li>
559<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
560or finish at a non-byte offset</a> in a record. Workaround: do not pack records
561or use representation clauses that result in a field of a non-discrete type
562starting or finishing in the middle of a byte.</li>
563<li>The lli interpreter <a href="http://llvm.org/PR2009">considers 'main'
564as generated by the Ada binder to be invalid</a>.
565Workaround: hand edit the file to use pointers for argv and envp rather than
566integers.</li>
567<li>The -fstack-check option <a href="http://llvm.org/PR2008">is ignored</a>.</li>
568</ul>
569</div>
570
571<!-- ======================================================================= -->
572<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]573 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]574</div>
575
576<div class="doc_text">
577
578<ul>
579<li>The llvm-gcc 4.2 gfortran front-end supports a broad range of Fortran code, but does
580<a href="http://llvm.org/PR1971">not support EQUIVALENCE yet</a>.</li>
581</ul>
582</div>
583
584
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]585
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]586<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]587<div class="doc_section">
588 <a name="additionalinfo">Additional Information</a>
589</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]590<!-- *********************************************************************** -->
591
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]592<div class="doc_text">
593
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]594<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]595href="http://llvm.org">LLVM web page</a>, in particular in the <a
596href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]597contains versions of the API documentation which is up-to-date with the
598Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]599You can access versions of these documents specific to this release by going
600into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]601
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]602<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]603us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]604lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]605
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]606</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]607
608<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]609
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]610<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]611<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]612 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]613 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
614 <a href="http://validator.w3.org/check/referer"><img
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]615 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]616
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]617 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]618 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]619</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]620
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]621</body>
622</html>