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gerrit-public.fairphone.software / toolchain / llvm-project / 03a4ad4db95ff1a9351d37897934f8d3ef8ca26e / . / llvm / docs / ReleaseNotes.html
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Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]7 <title>LLVM 2.3 Release Notes</title>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]8</head>
9<body>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]10
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]11<div class="doc_title">LLVM 2.3 Release Notes</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]12
13<ol>
Misha Brukman80731b92003-11-22 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 Lattner77a51732004-04-30 22:17:12 +0000[diff] [blame]16 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]18 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]19 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]20</ol>
21
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]22<div class="doc_author">
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]23 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]24</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]25
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]26<!-- Done through Week-of-Mon-20080324.txt -->
27
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]28<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]29<div class="doc_section">
30 <a name="intro">Introduction</a>
31</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]32<!-- *********************************************************************** -->
33
Misha Brukman80731b92003-11-22 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 Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]37infrastructure, release 2.3. Here we describe the status of LLVM, including
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]38major improvements from the previous release and any known problems. All LLVM
Chris Lattner98a33492007-05-09 04:58:11 +0000[diff] [blame]39releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]40releases web site</a>.</p>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]41
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]42<p>For more information about LLVM, including information about the latest
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]43release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattnere7525b52003-10-07 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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]46list</a> is a good place to send them.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]47
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]48<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner0a1fd102007-09-21 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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]52
53</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]54
55<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]56<div class="doc_section">
57 <a name="whatsnew">What's New?</a>
58</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]59<!-- *********************************************************************** -->
60
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]61<div class="doc_text">
62
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]63<p>This is the fourteenth public release of the LLVM Compiler Infrastructure.
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]64It includes a large number of features and refinements from LLVM 2.2.</p>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]65
Chris Lattner21a90402004-05-24 04:50:25 +0000[diff] [blame]66</div>
67
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]68<!-- Unfinished features in 2.3:
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]69 Machine LICM
70 Machine Sinking
71 LegalizeDAGTypes
72 -->
73
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]74<!--=========================================================================-->
Chris Lattner406bddf2005-05-15 05:44:51 +0000[diff] [blame]75<div class="doc_subsection">
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]76<a name="changes">Major Changes in LLVM 2.3</a>
Chris Lattnera2735862008-02-10 07:04:35 +0000[diff] [blame]77</div>
78
79<div class="doc_text">
80
Chris Lattnere38ac152008-02-12 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 Lattnerb7112222008-06-05 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 Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]86
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]87<p>LLVM 2.3 renames the LLVMBuilder and LLVMFoldingBuilder classes to
88 IRBuilder.</p>
89
Chris Lattnercdc44ed2008-02-06 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 Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]99<p>LLVM 2.3 includes several major new capabilities:</p>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]100
101<ul>
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]102<li>Multiple Return Value Support</li>
Chris Lattner618a99f2008-06-05 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 Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]125<li>Reimplemented <a href="LinkTimeOptimization.html">LTO interface</a> in
126 C.</li>
Chris Lattner618a99f2008-06-05 06:57:39 +0000[diff] [blame]127
128
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]129<li>kaleidoscope tutorial in ocaml.</li>
Chris Lattner618a99f2008-06-05 06:57:39 +0000[diff] [blame]130
Chris Lattner458e79f2008-02-10 08:18:42 +0000[diff] [blame]131</ul>
132
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]133</div>
134
Chris Lattnerb7112222008-06-05 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 Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]163<!--=========================================================================-->
164<div class="doc_subsection">
Chris Lattnerdd6acc02008-02-10 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 Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]172
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]173Common linkage?
174
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]175Atomic operation support, Alpha, X86, X86-64, PowerPC. "__sync_synchronize"
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]176
177<ul>
Gordon Henriksen03a4ad42008-06-05 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 Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]181</ul>
182
183</div>
184
185<!--=========================================================================-->
186<div class="doc_subsection">
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]187<a name="codegen">Code Generator Improvements</a>
188</div>
189
190<div class="doc_text">
191
Chris Lattner2b8a52e2008-02-10 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 Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]195
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]196<ul>
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]197<li>MemOperand in the code generator: describe me!.</li>
198<li>i128 support and APInt through most of codegen.</li>
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]199<li>Several compile time speedups for code with large basic blocks.</li>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]200</ul>
201
202</div>
203
204<!--=========================================================================-->
205<div class="doc_subsection">
206<a name="optimizer">Optimizer Improvements</a>
207</div>
208
209<div class="doc_text">
210
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]211<p>In addition to a huge array of bug fixes and minor performance tweaks, the
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]212LLVM 2.3 optimizers support a few major enhancements:</p>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]213
214<ul>
215
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]216<li>Loop index set splitting on by default: describe me.</li>
217<li>LLVM includes a new memcpy optimization pass which optimizes out dead
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]218memcpy calls, unneeded copies of aggregates, and handles the return slot
219optimization. The LLVM optimizer now notices long sequences of consequtive
220stores and merges them into memcpy's where profitable.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]221</ul>
222
223</div>
224
225
226<!--=========================================================================-->
227<div class="doc_subsection">
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]228<a name="x86specific">X86/X86-64 Specific Improvements</a>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]229</div>
Chris Lattner727c3742007-05-18 06:33:02 +0000[diff] [blame]230
Chris Lattner89e761c2006-04-18 06:32:08 +0000[diff] [blame]231<div class="doc_text">
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]232<p>New target-specific features include:
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]233</p>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]234
235<ul>
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]236<li>llvm-gcc's X86-64 ABI conformance is far improved, particularly in the
237 area of passing and returning structures by value. llvm-gcc Compiled code
238 now interoperates very well on X86-64 systems with other compilers.</li>
239
240<li>The LLVM X86 backend now supports the support SSE 4.1 instruction set, and
241 the llvm-gcc 4.2 front-end supports the SSE 4.1 compiler builtins.</li>
242
243<li>The X86 backend now does a number of optimizations that aim to avoid
244 converting numbers back and forth from SSE registers to the X87 floating
245 point stack.</li>
Chris Lattner618a99f2008-06-05 06:57:39 +0000[diff] [blame]246
247<li>The X86 backend supports stack realignment, which is particularly useful for
248 vector code on OS's without 16-byte aligned stacks.</li>
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]249
250<li>The X86 backend now supports the "sseregparm" options in GCC, which allow
251 functions to be tagged as passing floating point values in SSE
252 registers.</li>
253
254<li>Trampolines (taking the address of a nested function) now work on
255 Linux/x86-64.</li>
256
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]257<li><tt>__builtin_prefetch</tt> is now compiled into the appropriate prefetch
258 instructions instead of being ignored.</li>
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]259
Chris Lattner8ce1ba42007-05-17 21:41:31 +0000[diff] [blame]260</ul>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]261
Chris Lattner8ce1ba42007-05-17 21:41:31 +0000[diff] [blame]262</div>
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]263
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]264<!--=========================================================================-->
265<div class="doc_subsection">
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]266<a name="targetspecific">Other Target Specific Improvements</a>
267</div>
268
269<div class="doc_text">
270<p>New target-specific features include:
271</p>
272
273<ul>
274<li>The LLVM C backend now supports vectors code.</li>
275
276
277</ul>
278
279</div>
280
281
282
283<!--=========================================================================-->
284<div class="doc_subsection">
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]285<a name="otherimprovements">Other Improvements</a>
286</div>
287
288<div class="doc_text">
289<p>New features include:
290</p>
291
292<ul>
Chris Lattner618a99f2008-06-05 06:57:39 +0000[diff] [blame]293<li>LLVM now builds with GCC 4.3.</li>
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]294<li>llvm2cpp tool was moved into llc, use llc -march=cpp</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]295</ul>
296
297</div>
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]298
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]299<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]300<div class="doc_section">
301 <a name="portability">Portability and Supported Platforms</a>
302</div>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]303<!-- *********************************************************************** -->
304
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]305<div class="doc_text">
306
John Criswell64307722004-12-08 20:35:47 +0000[diff] [blame]307<p>LLVM is known to work on the following platforms:</p>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]308
309<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]310<li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
Reid Spencer9803b402005-05-17 02:47:27 +0000[diff] [blame]311 (and probably other unix-like systems).</li>
Chris Lattner7422bce2008-02-06 06:30:34 +0000[diff] [blame]312<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit and
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]313 64-bit modes.</li>
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]314<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]315<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
316 support is available for native builds with Visual C++).</li>
317<li>Sun UltraSPARC workstations running Solaris 8.</li>
John Criswelld5234922005-05-13 20:28:15 +0000[diff] [blame]318<li>Alpha-based machines running Debian GNU/Linux.</li>
319<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]320</ul>
321
Chris Lattner618a99f2008-06-05 06:57:39 +0000[diff] [blame]322<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekee3e557e2004-05-09 05:28:35 +0000[diff] [blame]323to the machine and operating system on which it is built. However, minor
324porting may be required to get LLVM to work on new platforms. We welcome your
325portability patches and reports of successful builds or error messages.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]326
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]327</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]328
329<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]330<div class="doc_section">
331 <a name="knownproblems">Known Problems</a>
332</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]333<!-- *********************************************************************** -->
334
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]335<div class="doc_text">
336
337<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]338component. As new problems are discovered, they will be added to these
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]339sections. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]340href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]341there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]342
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]343</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]344
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]345<!-- ======================================================================= -->
346<div class="doc_subsection">
347 <a name="experimental">Experimental features included with this release</a>
348</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]349
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]350<div class="doc_text">
351
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]352<p>The following components of this LLVM release are either untested, known to
353be broken or unreliable, or are in early development. These components should
354not be relied on, and bugs should not be filed against them, but they may be
355useful to some people. In particular, if you would like to work on one of these
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]356components, please contact us on the <a
357href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]358
359<ul>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]360<li>The MSIL, IA64, Alpha, SPU, and MIPS backends are experimental.</li>
Chris Lattner7422bce2008-02-06 06:30:34 +0000[diff] [blame]361<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
362 value for this option.</li>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]363</ul>
364
365</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]366
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]367<!-- ======================================================================= -->
368<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]369 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]370</div>
371
372<div class="doc_text">
373
374<ul>
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]375<li>The X86 backend does not yet support all <a
376 href="http://llvm.org/PR879">inline assembly that uses the X86 floating
377 point stack</a>. It supports the 'f' and 't' constraints, but not 'u'.</li>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]378<li>The X86 backend generates inefficient floating point code when configured to
379 generate code for systems that don't have SSE2.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]380</ul>
381
382</div>
383
384<!-- ======================================================================= -->
385<div class="doc_subsection">
386 <a name="ppc-be">Known problems with the PowerPC back-end</a>
387</div>
388
389<div class="doc_text">
390
391<ul>
Nicolas Geoffray77d99502007-05-15 09:21:28 +0000[diff] [blame]392<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]393compilation, and lacks support for debug information.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]394</ul>
395
396</div>
397
398<!-- ======================================================================= -->
399<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]400 <a name="arm-be">Known problems with the ARM back-end</a>
401</div>
402
403<div class="doc_text">
404
405<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]406<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands47fc0a22007-09-26 15:59:54 +0000[diff] [blame]407processors, thumb programs can crash or produce wrong
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]408results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]409<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
410</li>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]411<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly execute
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]412programs compiled with LLVM. Please use more recent versions of QEMU.</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]413</ul>
414
415</div>
416
417<!-- ======================================================================= -->
418<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]419 <a name="sparc-be">Known problems with the SPARC back-end</a>
420</div>
421
422<div class="doc_text">
423
424<ul>
425<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
426 support the 64-bit SPARC ABI (-m64).</li>
427</ul>
428
429</div>
430
431<!-- ======================================================================= -->
432<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]433 <a name="alpha-be">Known problems with the Alpha back-end</a>
434</div>
435
436<div class="doc_text">
437
438<ul>
439
440<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
441appropriate nops inserted to ensure restartability.</li>
442
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]443</ul>
444</div>
445
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]446<!-- ======================================================================= -->
447<div class="doc_subsection">
448 <a name="ia64-be">Known problems with the IA64 back-end</a>
449</div>
450
451<div class="doc_text">
452
453<ul>
454
455<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
456made where the argument is not 16-byte aligned, as required on IA64. (Strictly
457speaking this is not a bug in the IA64 back-end; it will also be encountered
458when building C++ programs using the C back-end.)</li>
459
460<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
461ABI compliant layout of v-tables</a>. In particular, it just stores function
462pointers instead of function descriptors in the vtable. This bug prevents
463mixing C++ code compiled with LLVM with C++ objects compiled by other C++
464compilers.</li>
465
466<li>There are a few ABI violations which will lead to problems when mixing LLVM
467output with code built with other compilers, particularly for floating-point
468programs.</li>
469
470<li>Defining vararg functions is not supported (but calling them is ok).</li>
471
Chris Lattner98a33492007-05-09 04:58:11 +0000[diff] [blame]472<li>The Itanium backend has bitrotted somewhat.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]473</ul>
474
475</div>
476
477<!-- ======================================================================= -->
478<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]479 <a name="c-be">Known problems with the C back-end</a>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]480</div>
481
482<div class="doc_text">
483
484<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]485<li><a href="http://llvm.org/PR802">The C backend has only basic support for
486 inline assembly code</a>.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000[diff] [blame]487<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
488 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
489 C++ code compiled with LLC or native compilers.</li>
Duncan Sandse09506a2008-02-10 13:40:55 +0000[diff] [blame]490<li>The C backend does not support all exception handling constructs.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]491</ul>
492
493</div>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]494
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]495
496<!-- ======================================================================= -->
497<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]498 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]499</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000[diff] [blame]500
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]501<!-- _______________________________________________________________________ -->
Chris Lattner5a8a7282003-12-14 05:03:43 +0000[diff] [blame]502<div class="doc_subsubsection">Bugs</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]503
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]504<div class="doc_text">
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]505
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]506<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
507Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]508llvmdev mailing list if you are interested.</p>
Chris Lattner44124232006-08-08 17:27:28 +0000[diff] [blame]509
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]510<p>The only major language feature of GCC not supported by llvm-gcc is
511 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
512 are only supported on some targets. For example, trampolines are only
513 supported on some targets, which are used when you take the address of a
514 nested function.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]515
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]516<p>If you run into GCC extensions which are not supported, please let us know.
517</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]518
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]519</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]520
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]521<!-- ======================================================================= -->
522<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]523 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]524</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]525
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]526<div class="doc_text">
527
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]528<p>The C++ front-end is considered to be fully
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]529tested and works for a number of non-trivial programs, including LLVM
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]530itself, Qt, Mozilla, etc.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]531
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]532<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]533<li>Exception handling works well on the X86 and PowerPC targets, including
534x86-64 darwin. This works when linking to a libstdc++ compiled by GCC. It is
535supported on x86-64 linux, but that is disabled by default in this release.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]536</ul>
Chris Lattner46ecf612003-10-07 22:14:37 +0000[diff] [blame]537
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]538</div>
539
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]540
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]541<!-- ======================================================================= -->
542<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]543 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]544</div>
545
546<div class="doc_text">
547The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
548technology and problems should be expected.
549<ul>
550<li>The Ada front-end currently only builds on x86-32. This is mainly due
551to lack of trampoline support (pointers to nested functions) on other platforms,
552however it <a href="http://llvm.org/PR2006">also fails to build on x86-64</a>
553which does support trampolines.</li>
554<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
555Workaround: configure with --disable-bootstrap.</li>
556<li>The c380004 and <a href="http://llvm.org/PR2010">c393010</a> ACATS tests
557fail (c380004 also fails with gcc-4.2 mainline).</li>
558<li>Many gcc specific Ada tests continue to crash the compiler.</li>
559<li>The -E binder option (exception backtraces)
560<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
561crashing if an exception is raised. Workaround: do not use -E.</li>
562<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
563or finish at a non-byte offset</a> in a record. Workaround: do not pack records
564or use representation clauses that result in a field of a non-discrete type
565starting or finishing in the middle of a byte.</li>
566<li>The lli interpreter <a href="http://llvm.org/PR2009">considers 'main'
567as generated by the Ada binder to be invalid</a>.
568Workaround: hand edit the file to use pointers for argv and envp rather than
569integers.</li>
570<li>The -fstack-check option <a href="http://llvm.org/PR2008">is ignored</a>.</li>
571</ul>
572</div>
573
574<!-- ======================================================================= -->
575<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]576 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]577</div>
578
579<div class="doc_text">
580
581<ul>
582<li>The llvm-gcc 4.2 gfortran front-end supports a broad range of Fortran code, but does
583<a href="http://llvm.org/PR1971">not support EQUIVALENCE yet</a>.</li>
584</ul>
585</div>
586
587
Chris Lattnerb62a5f02005-05-15 16:01:20 +0000[diff] [blame]588
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]589<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]590<div class="doc_section">
591 <a name="additionalinfo">Additional Information</a>
592</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]593<!-- *********************************************************************** -->
594
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]595<div class="doc_text">
596
Chris Lattnercb5596d2005-05-16 17:13:10 +0000[diff] [blame]597<p>A wide variety of additional information is available on the <a
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]598href="http://llvm.org">LLVM web page</a>, in particular in the <a
599href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]600contains versions of the API documentation which is up-to-date with the
601Subversion version of the source code.
Misha Brukman96158092005-03-30 19:14:24 +0000[diff] [blame]602You can access versions of these documents specific to this release by going
603into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]604
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]605<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]606us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]607lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]608
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]609</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]610
611<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]612
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]613<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]614<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000[diff] [blame]615 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]616 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
617 <a href="http://validator.w3.org/check/referer"><img
Chris Lattner458e79f2008-02-10 08:18:42 +0000[diff] [blame]618 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]619
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]620 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]621 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]622</address>
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Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]624</body>
625</html>