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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / bc5786ba47089ee38bc3fab88af17d96db7ea9dd / . / docs / ReleaseNotes.html
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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
26<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]27<div class="doc_section">
28 <a name="intro">Introduction</a>
29</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]30<!-- *********************************************************************** -->
31
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]32<div class="doc_text">
33
34<p>This document contains the release notes for the LLVM compiler
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]35infrastructure, release 2.3. Here we describe the status of LLVM, including
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]36major improvements from the previous release and any known problems. All LLVM
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]37releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]38releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]39
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]40<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]41release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]42web site</a>. If you have questions or comments, the <a
43href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]44list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]45
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]46<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]47main LLVM web page, this document applies to the <i>next</i> release, not the
48current one. To see the release notes for a specific releases, please see the
49<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]50
51</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]52
53<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]54<div class="doc_section">
55 <a name="whatsnew">What's New?</a>
56</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]57<!-- *********************************************************************** -->
58
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]59<div class="doc_text">
60
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]61<p>This is the fourteenth public release of the LLVM Compiler Infrastructure.
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]62It includes a large number of features and refinements from LLVM 2.2.</p>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]63
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]64</div>
65
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]66<!-- Unfinished features in 2.3:
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]67 Index Set Splitting not enabled by default
68 Machine LICM
69 Machine Sinking
70 LegalizeDAGTypes
71 -->
72
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]73<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]74<div class="doc_subsection">
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]75<a name="deprecation">Removed features in LLVM 2.3</a>
Chris Lattnerb4c68cd2008-02-10 07:04:35 +0000[diff] [blame]76</div>
77
78<div class="doc_text">
79
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]80<p>LLVM 2.2 was the last LLVM release to support llvm-gcc 4.0 and llvm-upgrade.
81llvm-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]82upgrading LLVM 1.9 files to LLVM 2.x syntax, but you can always use a previous
83LLVM release to do this. One nice impact of this is that the LLVM regressionn
84test suite no longer depends on llvm-upgrade, which makes it run faster.</p>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]85
86</div>
87
88<!--=========================================================================-->
89<div class="doc_subsection">
90<a name="majorfeatures">Major New Features</a>
91</div>
92
93<div class="doc_text">
94
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]95<p>LLVM 2.3 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]96
97<ul>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]98<li>Multiple Return Value Support</li>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame^]99
100
101<li><p>LLVM 2.3 includes a complete reimplementation of the "llvmc" tool. It is
102designed to overcome several problems of the original llvmc and to provide a
103superset of the features as the 'gcc' driver.</p>
104
105<p>The main features of llvmc2 is:</p>
106
107<ul>
108<li>Extended handling of command line options and smart rules for
109dispatching them to different tools.</li>
110<li>Flexible (and extensible) rules for defining different tools.</li>
111<li>The different intermediate steps performed by tools are represented
112as edged in the abstract graph.</li>
113</l>The 'language' for driver behaviour definition is tablegen and thus
114it's relatively easy to add new features.</li>
115<li>The definition of driver is transformed into set of C++ classes, thus
116no runtime interpretation is needed.</li>
117</ul>
118
119</li>
120
121
122
123
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]124</ul>
125
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]126</div>
127
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]128
129<!--=========================================================================-->
130<div class="doc_subsection">
131<a name="frontends">llvm-gcc 4.2 Improvements and Clang</a>
132</div>
133
134<div class="doc_text">
135
136<p>LLVM 2.3 fully supports llvm-gcc 4.2 front-end.</p>
137
138<p>llvm-gcc 4.2 includes numerous fixes to better support the Objective-C
139front-end. Objective-C now works very well on Mac OS/X.</p>
140
141<p>llvm-gcc 4.2 includes many other fixes which improve conformance with the
142relevant parts of the GCC testsuite.</p>
143
144<p>The <a href="http://clang.llvm.org/">clang project</a> is an effort to build
145a set of new 'llvm native' front-end technologies for the LLVM optimizer
146and code generator. Currently, its C and Objective-C support is maturing
147nicely, and it has advanced source-to-source analysis and transformation
148capabilities. If you are interested in building source-level tools for C and
149Objective-C (and eventually C++), you should take a look. However, note that
150clang is not an official part of the LLVM 2.3 release. If you are interested in
151this project, please see its <a href="http://clang.llvm.org/">web site</a>.</p>
152
153</div>
154
155
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]156<!--=========================================================================-->
157<div class="doc_subsection">
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]158<a name="coreimprovements">LLVM Core Improvements</a>
159</div>
160
161<div class="doc_text">
162<p>New features include:
163</p>
164
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]165
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]166Common linkage?
167
168Atomic operation support, Alpha, X86, PowerPC. "__sync_syncronize"
169
170<ul>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]171</ul>
172
173</div>
174
175<!--=========================================================================-->
176<div class="doc_subsection">
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]177<a name="codegen">Code Generator Improvements</a>
178</div>
179
180<div class="doc_text">
181
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]182<p>We put a significant amount of work into the code generator infrastructure,
183which allows us to implement more aggressive algorithms and make it run
184faster:</p>
Chris Lattnerd4298712007-09-26 05:44:21 +0000[diff] [blame]185
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]186<ul>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]187<li>MemOperand in the code generator: describe me!.</li>
188<li>i128 support and APInt through most of codegen.</li>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]189</ul>
190
191</div>
192
193<!--=========================================================================-->
194<div class="doc_subsection">
195<a name="optimizer">Optimizer Improvements</a>
196</div>
197
198<div class="doc_text">
199
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]200<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]201LLVM 2.3 optimizers support a few major enhancements:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]202
203<ul>
204
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]205<li>Loop index set splitting on by default: describe me.</li>
206<li>LLVM includes a new memcpy optimization pass which optimizes out dead
207memcpy calls and unneeded copies of aggregates.</li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]208</ul>
209
210</div>
211
212
213<!--=========================================================================-->
214<div class="doc_subsection">
215<a name="targetspecific">Target Specific Improvements</a>
216</div>
Chris Lattner60893e52007-05-18 06:33:02 +0000[diff] [blame]217
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]218<div class="doc_text">
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]219<p>New target-specific features include:
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]220</p>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]221
222<ul>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]223<li>llvm-gcc's X86-64 ABI conformance is far improved, particularly in the
224 area of passing and returning structures by value. llvm-gcc Compiled code
225 now interoperates very well on X86-64 systems with other compilers.</li>
226
227<li>The LLVM X86 backend now supports the support SSE 4.1 instruction set, and
228 the llvm-gcc 4.2 front-end supports the SSE 4.1 compiler builtins.</li>
229
230<li>The X86 backend now does a number of optimizations that aim to avoid
231 converting numbers back and forth from SSE registers to the X87 floating
232 point stack.</li>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame^]233
234<li>The X86 backend supports stack realignment, which is particularly useful for
235 vector code on OS's without 16-byte aligned stacks.</li>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]236
237<li>The X86 backend now supports the "sseregparm" options in GCC, which allow
238 functions to be tagged as passing floating point values in SSE
239 registers.</li>
240
241<li>Trampolines (taking the address of a nested function) now work on
242 Linux/x86-64.</li>
243
244
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000[diff] [blame]245</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]246
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000[diff] [blame]247</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]248
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]249<!--=========================================================================-->
250<div class="doc_subsection">
251<a name="otherimprovements">Other Improvements</a>
252</div>
253
254<div class="doc_text">
255<p>New features include:
256</p>
257
258<ul>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame^]259<li>LLVM now builds with GCC 4.3.</li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]260</ul>
261
262</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]263
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]264<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]265<div class="doc_section">
266 <a name="portability">Portability and Supported Platforms</a>
267</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]268<!-- *********************************************************************** -->
269
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]270<div class="doc_text">
271
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]272<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]273
274<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]275<li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
Reid Spencer00812e22005-05-17 02:47:27 +0000[diff] [blame]276 (and probably other unix-like systems).</li>
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]277<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]278 64-bit modes.</li>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]279<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]280<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
281 support is available for native builds with Visual C++).</li>
282<li>Sun UltraSPARC workstations running Solaris 8.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]283<li>Alpha-based machines running Debian GNU/Linux.</li>
284<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]285</ul>
286
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame^]287<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]288to the machine and operating system on which it is built. However, minor
289porting may be required to get LLVM to work on new platforms. We welcome your
290portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]291
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]292</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]293
294<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]295<div class="doc_section">
296 <a name="knownproblems">Known Problems</a>
297</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]298<!-- *********************************************************************** -->
299
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]300<div class="doc_text">
301
302<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]303component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]304sections. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]305href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]306there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]307
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]308</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]309
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]310<!-- ======================================================================= -->
311<div class="doc_subsection">
312 <a name="experimental">Experimental features included with this release</a>
313</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]314
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]315<div class="doc_text">
316
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]317<p>The following components of this LLVM release are either untested, known to
318be broken or unreliable, or are in early development. These components should
319not be relied on, and bugs should not be filed against them, but they may be
320useful 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]321components, please contact us on the <a
322href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]323
324<ul>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]325<li>The MSIL, IA64, Alpha, SPU, and MIPS backends are experimental.</li>
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]326<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
327 value for this option.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]328</ul>
329
330</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]331
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]332<!-- ======================================================================= -->
333<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]334 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]335</div>
336
337<div class="doc_text">
338
339<ul>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]340<li>The X86 backend does not yet support <a href="http://llvm.org/PR879">inline
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]341 assembly that uses the X86 floating point stack</a>.</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]342<li>The X86 backend generates inefficient floating point code when configured to
343 generate code for systems that don't have SSE2.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]344</ul>
345
346</div>
347
348<!-- ======================================================================= -->
349<div class="doc_subsection">
350 <a name="ppc-be">Known problems with the PowerPC back-end</a>
351</div>
352
353<div class="doc_text">
354
355<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000[diff] [blame]356<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]357compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]358</ul>
359
360</div>
361
362<!-- ======================================================================= -->
363<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]364 <a name="arm-be">Known problems with the ARM back-end</a>
365</div>
366
367<div class="doc_text">
368
369<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]370<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000[diff] [blame]371processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]372results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]373<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
374</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]375<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]376programs compiled with LLVM. Please use more recent versions of QEMU.</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]377</ul>
378
379</div>
380
381<!-- ======================================================================= -->
382<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]383 <a name="sparc-be">Known problems with the SPARC back-end</a>
384</div>
385
386<div class="doc_text">
387
388<ul>
389<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
390 support the 64-bit SPARC ABI (-m64).</li>
391</ul>
392
393</div>
394
395<!-- ======================================================================= -->
396<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]397 <a name="alpha-be">Known problems with the Alpha back-end</a>
398</div>
399
400<div class="doc_text">
401
402<ul>
403
404<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
405appropriate nops inserted to ensure restartability.</li>
406
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]407</ul>
408</div>
409
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]410<!-- ======================================================================= -->
411<div class="doc_subsection">
412 <a name="ia64-be">Known problems with the IA64 back-end</a>
413</div>
414
415<div class="doc_text">
416
417<ul>
418
419<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
420made where the argument is not 16-byte aligned, as required on IA64. (Strictly
421speaking this is not a bug in the IA64 back-end; it will also be encountered
422when building C++ programs using the C back-end.)</li>
423
424<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
425ABI compliant layout of v-tables</a>. In particular, it just stores function
426pointers instead of function descriptors in the vtable. This bug prevents
427mixing C++ code compiled with LLVM with C++ objects compiled by other C++
428compilers.</li>
429
430<li>There are a few ABI violations which will lead to problems when mixing LLVM
431output with code built with other compilers, particularly for floating-point
432programs.</li>
433
434<li>Defining vararg functions is not supported (but calling them is ok).</li>
435
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]436<li>The Itanium backend has bitrotted somewhat.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]437</ul>
438
439</div>
440
441<!-- ======================================================================= -->
442<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]443 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]444</div>
445
446<div class="doc_text">
447
448<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]449<li><a href="http://llvm.org/PR802">The C backend has only basic support for
450 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000[diff] [blame]451<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
452 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
453 C++ code compiled with LLC or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]454<li>The C backend does not support all exception handling constructs.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]455</ul>
456
457</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]458
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]459
460<!-- ======================================================================= -->
461<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]462 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]463</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]464
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]465<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]466<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]467
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]468<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]469
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]470<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
471Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]472llvmdev mailing list if you are interested.</p>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]473
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]474<p>The only major language feature of GCC not supported by llvm-gcc is
475 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
476 are only supported on some targets. For example, trampolines are only
477 supported on some targets, which are used when you take the address of a
478 nested function.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]479
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]480<p>If you run into GCC extensions which are not supported, please let us know.
481</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]482
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]483</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]484
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]485<!-- ======================================================================= -->
486<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]487 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]488</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]489
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]490<div class="doc_text">
491
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]492<p>The C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]493tested and works for a number of non-trivial programs, including LLVM
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]494itself, Qt, Mozilla, etc.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]495
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]496<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]497<li>Exception handling works well on the X86 and PowerPC targets, including
498x86-64 darwin. This works when linking to a libstdc++ compiled by GCC. It is
499supported on x86-64 linux, but that is disabled by default in this release.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]500</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]501
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]502</div>
503
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]504
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]505<!-- ======================================================================= -->
506<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]507 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]508</div>
509
510<div class="doc_text">
511The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
512technology and problems should be expected.
513<ul>
514<li>The Ada front-end currently only builds on x86-32. This is mainly due
515to lack of trampoline support (pointers to nested functions) on other platforms,
516however it <a href="http://llvm.org/PR2006">also fails to build on x86-64</a>
517which does support trampolines.</li>
518<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
519Workaround: configure with --disable-bootstrap.</li>
520<li>The c380004 and <a href="http://llvm.org/PR2010">c393010</a> ACATS tests
521fail (c380004 also fails with gcc-4.2 mainline).</li>
522<li>Many gcc specific Ada tests continue to crash the compiler.</li>
523<li>The -E binder option (exception backtraces)
524<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
525crashing if an exception is raised. Workaround: do not use -E.</li>
526<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
527or finish at a non-byte offset</a> in a record. Workaround: do not pack records
528or use representation clauses that result in a field of a non-discrete type
529starting or finishing in the middle of a byte.</li>
530<li>The lli interpreter <a href="http://llvm.org/PR2009">considers 'main'
531as generated by the Ada binder to be invalid</a>.
532Workaround: hand edit the file to use pointers for argv and envp rather than
533integers.</li>
534<li>The -fstack-check option <a href="http://llvm.org/PR2008">is ignored</a>.</li>
535</ul>
536</div>
537
538<!-- ======================================================================= -->
539<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]540 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]541</div>
542
543<div class="doc_text">
544
545<ul>
546<li>The llvm-gcc 4.2 gfortran front-end supports a broad range of Fortran code, but does
547<a href="http://llvm.org/PR1971">not support EQUIVALENCE yet</a>.</li>
548</ul>
549</div>
550
551
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]552
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]553<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]554<div class="doc_section">
555 <a name="additionalinfo">Additional Information</a>
556</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]557<!-- *********************************************************************** -->
558
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]559<div class="doc_text">
560
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]561<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]562href="http://llvm.org">LLVM web page</a>, in particular in the <a
563href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]564contains versions of the API documentation which is up-to-date with the
565Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]566You can access versions of these documents specific to this release by going
567into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]568
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]569<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]570us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]571lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]572
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]573</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]574
575<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]576
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]577<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]578<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]579 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]580 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
581 <a href="http://validator.w3.org/check/referer"><img
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]582 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]583
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]584 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]585 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]586</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]587
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]588</body>
589</html>