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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 30073ff412fd50290c7df4cfe3d0ea7878ac2c66 / . / docs / ReleaseNotes.html
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4<head>
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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
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]84LLVM release to do this. One nice impact of this is that the LLVM regression
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]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
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]116as edges in the abstract graph.</li>
117<li>The 'language' for driver behaviour definition is tablegen and thus
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]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>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]122</li>
123
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]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>
Gordon Henriksen1494bcc2008-06-05 12:51:50 +0000[diff] [blame]178<li>The C and Ocaml bindings have received additional improvements. The
179bindings now cover pass managers, several transformation passes, iteration
180over the LLVM IR, target data, and parameter attribute lists.</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]181</ul>
182
183</div>
184
185<!--=========================================================================-->
186<div class="doc_subsection">
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]187<a name="codegen">Code Generator Improvements</a>
188</div>
189
190<div class="doc_text">
191
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]192<p>We put a significant amount of work into the code generator infrastructure,
193which allows us to implement more aggressive algorithms and make it run
194faster:</p>
Chris Lattnerd4298712007-09-26 05:44:21 +0000[diff] [blame]195
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]196<ul>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]197<li>MemOperand in the code generator: describe me!.</li>
Dan Gohman6e60ea42008-06-05 18:45:33 +0000[diff] [blame]198<li>The target-independent code generator infrastructure now uses LLVM's APInt
199 class to handle integer values, which allows it to support integer types
200 larger than 64 bits. Note that support for such types is also dependent on
Dan Gohman85765e62008-06-05 15:43:11 +0000[diff] [blame]201 target-specific support. Use of APInt is also a step toward support for
202 non-power-of-2 integer sizes.</li>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]203<li>Several compile time speedups for code with large basic blocks.</li>
Dan Gohman809d91e2008-06-05 15:46:36 +0000[diff] [blame]204<li>Several improvements which make llc's <tt>--view-sunit-dags</tt>
205 visualization of scheduling dependency graphs easier to understand.</li>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]206</ul>
207
208</div>
209
210<!--=========================================================================-->
211<div class="doc_subsection">
212<a name="optimizer">Optimizer Improvements</a>
213</div>
214
215<div class="doc_text">
216
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]217<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]218LLVM 2.3 optimizers support a few major enhancements:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]219
220<ul>
221
Devang Patel83a15d72008-06-05 21:44:00 +0000[diff] [blame]222<li>Loop index set splitting on by default.<p>
223This transformation hoists conditions from loop bodies and reduces loop's
224iteration space to improve performance. For example, <p>
225<pre>
226for (i = LB; i < UB; ++i)
227 if (i <= NV)
228 LOOP_BODY
229</pre>
230is transformed into
231<pre>
232NUB = min(NV+1, UB)
233for (i = LB; i < NUB; ++i)
234 LOOP_BODY
235</pre>
236</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]237<li>LLVM includes a new <tt>memcpy</tt> optimization pass which optimizes out dead
238<tt>memcpy</tt> calls, unneeded copies of aggregates, and handles the return slot
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]239optimization. The LLVM optimizer now notices long sequences of consequtive
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]240stores and merges them into <tt>memcpy</tt>s where profitable.</li>
241<li>Alignment detection for vector memory references and for <tt>memcpy</tt> and
242<tt>memset</tt> is now more aggressive.</li>
Owen Anderson30073ff2008-06-06 16:23:15 +0000[diff] [blame^]243
244<li>The aggressive dead code elimination (ADCE) optimization has been rewritten to make
245it both faster and safer in the presence of code containing infinite loops.
246Some of its prior functionality has been factored out into the loop deletion
247pass, which <em>is</em> safe for infinite loops.</li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]248</ul>
249
250</div>
251
252
253<!--=========================================================================-->
254<div class="doc_subsection">
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]255<a name="x86specific">X86/X86-64 Specific Improvements</a>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]256</div>
Chris Lattner60893e52007-05-18 06:33:02 +0000[diff] [blame]257
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]258<div class="doc_text">
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]259<p>New target-specific features include:
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]260</p>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]261
262<ul>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]263<li>llvm-gcc's X86-64 ABI conformance is far improved, particularly in the
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]264 area of passing and returning structures by value. llvm-gcc compiled code
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]265 now interoperates very well on X86-64 systems with other compilers.</li>
266
267<li>The LLVM X86 backend now supports the support SSE 4.1 instruction set, and
268 the llvm-gcc 4.2 front-end supports the SSE 4.1 compiler builtins.</li>
269
270<li>The X86 backend now does a number of optimizations that aim to avoid
271 converting numbers back and forth from SSE registers to the X87 floating
272 point stack.</li>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]273
274<li>The X86 backend supports stack realignment, which is particularly useful for
275 vector code on OS's without 16-byte aligned stacks.</li>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]276
277<li>The X86 backend now supports the "sseregparm" options in GCC, which allow
278 functions to be tagged as passing floating point values in SSE
279 registers.</li>
280
281<li>Trampolines (taking the address of a nested function) now work on
282 Linux/x86-64.</li>
283
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]284<li><tt>__builtin_prefetch</tt> is now compiled into the appropriate prefetch
285 instructions instead of being ignored.</li>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]286
Dan Gohman4e16d402008-06-05 16:15:39 +0000[diff] [blame]287<li>128-bit integers are now supported on x86-64 targets.</li>
288
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000[diff] [blame]289</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]290
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000[diff] [blame]291</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]292
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]293<!--=========================================================================-->
294<div class="doc_subsection">
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]295<a name="targetspecific">Other Target Specific Improvements</a>
296</div>
297
298<div class="doc_text">
299<p>New target-specific features include:
300</p>
301
302<ul>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]303<li>The LLVM C backend now supports vector code.</li>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]304
305
306</ul>
307
308</div>
309
310
311
312<!--=========================================================================-->
313<div class="doc_subsection">
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]314<a name="otherimprovements">Other Improvements</a>
315</div>
316
317<div class="doc_text">
318<p>New features include:
319</p>
320
321<ul>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]322<li>LLVM now builds with GCC 4.3.</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]323<li>llvm2cpp tool has been folded into llc, use <tt>llc -march=cpp</tt></li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]324</ul>
325
326</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]327
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]328<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]329<div class="doc_section">
330 <a name="portability">Portability and Supported Platforms</a>
331</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]332<!-- *********************************************************************** -->
333
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]334<div class="doc_text">
335
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]336<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]337
338<ul>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]339<li>Intel and AMD machines (IA32) running Red Hat Linux, Fedora Core and FreeBSD
Reid Spencer00812e22005-05-17 02:47:27 +0000[diff] [blame]340 (and probably other unix-like systems).</li>
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]341<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]342 64-bit modes.</li>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]343<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]344<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
345 support is available for native builds with Visual C++).</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]346<li>Sun UltraSPARC workstations running Solaris 10.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]347<li>Alpha-based machines running Debian GNU/Linux.</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]348<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]349</ul>
350
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]351<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]352to the machine and operating system on which it is built. However, minor
353porting may be required to get LLVM to work on new platforms. We welcome your
354portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]355
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]356</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]357
358<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]359<div class="doc_section">
360 <a name="knownproblems">Known Problems</a>
361</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]362<!-- *********************************************************************** -->
363
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]364<div class="doc_text">
365
366<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]367component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]368sections. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]369href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]370there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]371
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]372</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]373
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]374<!-- ======================================================================= -->
375<div class="doc_subsection">
376 <a name="experimental">Experimental features included with this release</a>
377</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]378
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]379<div class="doc_text">
380
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]381<p>The following components of this LLVM release are either untested, known to
382be broken or unreliable, or are in early development. These components should
383not be relied on, and bugs should not be filed against them, but they may be
384useful 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]385components, please contact us on the <a
386href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]387
388<ul>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]389<li>The MSIL, IA64, Alpha, SPU, and MIPS backends are experimental.</li>
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]390<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
391 value for this option.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]392</ul>
393
394</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]395
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]396<!-- ======================================================================= -->
397<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]398 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]399</div>
400
401<div class="doc_text">
402
403<ul>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]404<li>The X86 backend does not yet support all <a
405 href="http://llvm.org/PR879">inline assembly that uses the X86 floating
406 point stack</a>. It supports the 'f' and 't' constraints, but not 'u'.</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]407<li>The X86 backend generates inefficient floating point code when configured to
408 generate code for systems that don't have SSE2.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]409</ul>
410
411</div>
412
413<!-- ======================================================================= -->
414<div class="doc_subsection">
415 <a name="ppc-be">Known problems with the PowerPC back-end</a>
416</div>
417
418<div class="doc_text">
419
420<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000[diff] [blame]421<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]422compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]423</ul>
424
425</div>
426
427<!-- ======================================================================= -->
428<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]429 <a name="arm-be">Known problems with the ARM back-end</a>
430</div>
431
432<div class="doc_text">
433
434<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]435<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000[diff] [blame]436processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]437results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]438<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
439</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]440<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]441programs compiled with LLVM. Please use more recent versions of QEMU.</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]442</ul>
443
444</div>
445
446<!-- ======================================================================= -->
447<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]448 <a name="sparc-be">Known problems with the SPARC back-end</a>
449</div>
450
451<div class="doc_text">
452
453<ul>
454<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
455 support the 64-bit SPARC ABI (-m64).</li>
456</ul>
457
458</div>
459
460<!-- ======================================================================= -->
461<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]462 <a name="alpha-be">Known problems with the Alpha back-end</a>
463</div>
464
465<div class="doc_text">
466
467<ul>
468
469<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
470appropriate nops inserted to ensure restartability.</li>
471
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]472</ul>
473</div>
474
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]475<!-- ======================================================================= -->
476<div class="doc_subsection">
477 <a name="ia64-be">Known problems with the IA64 back-end</a>
478</div>
479
480<div class="doc_text">
481
482<ul>
483
484<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
485made where the argument is not 16-byte aligned, as required on IA64. (Strictly
486speaking this is not a bug in the IA64 back-end; it will also be encountered
487when building C++ programs using the C back-end.)</li>
488
489<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
490ABI compliant layout of v-tables</a>. In particular, it just stores function
491pointers instead of function descriptors in the vtable. This bug prevents
492mixing C++ code compiled with LLVM with C++ objects compiled by other C++
493compilers.</li>
494
495<li>There are a few ABI violations which will lead to problems when mixing LLVM
496output with code built with other compilers, particularly for floating-point
497programs.</li>
498
499<li>Defining vararg functions is not supported (but calling them is ok).</li>
500
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]501<li>The Itanium backend has bitrotted somewhat.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]502</ul>
503
504</div>
505
506<!-- ======================================================================= -->
507<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]508 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]509</div>
510
511<div class="doc_text">
512
513<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]514<li><a href="http://llvm.org/PR802">The C backend has only basic support for
515 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000[diff] [blame]516<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
517 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
518 C++ code compiled with LLC or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]519<li>The C backend does not support all exception handling constructs.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]520</ul>
521
522</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]523
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]524
525<!-- ======================================================================= -->
526<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]527 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]528</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]529
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]530<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]531<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]532
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]533<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]534
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]535<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
536Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]537llvmdev mailing list if you are interested.</p>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]538
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]539<p>The only major language feature of GCC not supported by llvm-gcc is
540 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
541 are only supported on some targets. For example, trampolines are only
542 supported on some targets, which are used when you take the address of a
543 nested function.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]544
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]545<p>If you run into GCC extensions which are not supported, please let us know.
546</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]547
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]548</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]549
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]550<!-- ======================================================================= -->
551<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]552 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]553</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]554
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]555<div class="doc_text">
556
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]557<p>The C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]558tested and works for a number of non-trivial programs, including LLVM
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]559itself, Qt, Mozilla, etc.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]560
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]561<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]562<li>Exception handling works well on the X86 and PowerPC targets, including
563x86-64 darwin. This works when linking to a libstdc++ compiled by GCC. It is
564supported on x86-64 linux, but that is disabled by default in this release.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]565</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]566
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]567</div>
568
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]569
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]570<!-- ======================================================================= -->
571<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]572 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]573</div>
574
575<div class="doc_text">
576The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
577technology and problems should be expected.
578<ul>
579<li>The Ada front-end currently only builds on x86-32. This is mainly due
580to lack of trampoline support (pointers to nested functions) on other platforms,
581however it <a href="http://llvm.org/PR2006">also fails to build on x86-64</a>
582which does support trampolines.</li>
583<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
584Workaround: configure with --disable-bootstrap.</li>
585<li>The c380004 and <a href="http://llvm.org/PR2010">c393010</a> ACATS tests
586fail (c380004 also fails with gcc-4.2 mainline).</li>
587<li>Many gcc specific Ada tests continue to crash the compiler.</li>
588<li>The -E binder option (exception backtraces)
589<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
590crashing if an exception is raised. Workaround: do not use -E.</li>
591<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
592or finish at a non-byte offset</a> in a record. Workaround: do not pack records
593or use representation clauses that result in a field of a non-discrete type
594starting or finishing in the middle of a byte.</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]595<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers 'main'
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]596as generated by the Ada binder to be invalid</a>.
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]597Workaround: hand edit the file to use pointers for <tt>argv</tt> and <tt>envp</tt> rather than
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]598integers.</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]599<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is ignored</a>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]600</ul>
601</div>
602
603<!-- ======================================================================= -->
604<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]605 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]606</div>
607
608<div class="doc_text">
609
610<ul>
611<li>The llvm-gcc 4.2 gfortran front-end supports a broad range of Fortran code, but does
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]612<a href="http://llvm.org/PR1971">not support <tt>EQUIVALENCE</tt> yet</a>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]613</ul>
614</div>
615
616
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]617
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]618<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]619<div class="doc_section">
620 <a name="additionalinfo">Additional Information</a>
621</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]622<!-- *********************************************************************** -->
623
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]624<div class="doc_text">
625
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]626<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]627href="http://llvm.org">LLVM web page</a>, in particular in the <a
628href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]629contains versions of the API documentation which is up-to-date with the
630Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]631You can access versions of these documents specific to this release by going
632into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]633
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]634<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]635us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]636lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]637
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]638</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]639
640<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]641
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]642<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]643<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]644 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]645 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
646 <a href="http://validator.w3.org/check/referer"><img
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]647 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]648
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]649 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]650 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]651</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]652
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]653</body>
654</html>