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gerrit-public.fairphone.software / toolchain / llvm-project / 80ae8a71944e8f794a75691fc4d7640f2085c64e / . / llvm / docs / ReleaseNotes.html
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Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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4<head>
Reid Spencere4190fa2004-11-18 18:38:58 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]6 <link rel="stylesheet" href="llvm.css" type="text/css">
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
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame^]84LLVM release to do this. One nice impact of this is that the LLVM regression
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]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
Gabor Greif80ae8a72008-06-05 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 Lattner618a99f2008-06-05 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 Lattner618a99f2008-06-05 06:57:39 +0000[diff] [blame]122</li>
123
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame^]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>
Dan Gohman46105562008-06-05 15:43:11 +0000[diff] [blame]198<li>Target-independent codegen infastructure now uses LLVM's APInt class for
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame^]199 handling integer values, which allows it to support integer types larger
Dan Gohman46105562008-06-05 15:43:11 +0000[diff] [blame]200 than 64 bits. Note that support for such types is also dependent on
201 target-specific support. Use of APInt is also a step toward support for
202 non-power-of-2 integer sizes.</li>
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]203<li>Several compile time speedups for code with large basic blocks.</li>
Dan Gohman23254a82008-06-05 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 Lattner2b8a52e2008-02-10 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 Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]217<p>In addition to a huge array of bug fixes and minor performance tweaks, the
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]218LLVM 2.3 optimizers support a few major enhancements:</p>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]219
220<ul>
221
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]222<li>Loop index set splitting on by default: describe me.</li>
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame^]223<li>LLVM includes a new <tt>memcpy</tt> optimization pass which optimizes out dead
224<tt>memcpy</tt> calls, unneeded copies of aggregates, and handles the return slot
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]225optimization. The LLVM optimizer now notices long sequences of consequtive
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame^]226stores and merges them into <tt>memcpy</tt>s where profitable.</li>
227<li>Alignment detection for vector memory references and for <tt>memcpy</tt> and
228<tt>memset</tt> is now more aggressive.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]229</ul>
230
231</div>
232
233
234<!--=========================================================================-->
235<div class="doc_subsection">
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]236<a name="x86specific">X86/X86-64 Specific Improvements</a>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]237</div>
Chris Lattner727c3742007-05-18 06:33:02 +0000[diff] [blame]238
Chris Lattner89e761c2006-04-18 06:32:08 +0000[diff] [blame]239<div class="doc_text">
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]240<p>New target-specific features include:
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]241</p>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]242
243<ul>
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]244<li>llvm-gcc's X86-64 ABI conformance is far improved, particularly in the
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame^]245 area of passing and returning structures by value. llvm-gcc compiled code
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]246 now interoperates very well on X86-64 systems with other compilers.</li>
247
248<li>The LLVM X86 backend now supports the support SSE 4.1 instruction set, and
249 the llvm-gcc 4.2 front-end supports the SSE 4.1 compiler builtins.</li>
250
251<li>The X86 backend now does a number of optimizations that aim to avoid
252 converting numbers back and forth from SSE registers to the X87 floating
253 point stack.</li>
Chris Lattner618a99f2008-06-05 06:57:39 +0000[diff] [blame]254
255<li>The X86 backend supports stack realignment, which is particularly useful for
256 vector code on OS's without 16-byte aligned stacks.</li>
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]257
258<li>The X86 backend now supports the "sseregparm" options in GCC, which allow
259 functions to be tagged as passing floating point values in SSE
260 registers.</li>
261
262<li>Trampolines (taking the address of a nested function) now work on
263 Linux/x86-64.</li>
264
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]265<li><tt>__builtin_prefetch</tt> is now compiled into the appropriate prefetch
266 instructions instead of being ignored.</li>
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]267
Dan Gohmanb0ec18b2008-06-05 16:15:39 +0000[diff] [blame]268<li>128-bit integers are now supported on x86-64 targets.</li>
269
Chris Lattner8ce1ba42007-05-17 21:41:31 +0000[diff] [blame]270</ul>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]271
Chris Lattner8ce1ba42007-05-17 21:41:31 +0000[diff] [blame]272</div>
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]273
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]274<!--=========================================================================-->
275<div class="doc_subsection">
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]276<a name="targetspecific">Other Target Specific Improvements</a>
277</div>
278
279<div class="doc_text">
280<p>New target-specific features include:
281</p>
282
283<ul>
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame^]284<li>The LLVM C backend now supports vector code.</li>
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]285
286
287</ul>
288
289</div>
290
291
292
293<!--=========================================================================-->
294<div class="doc_subsection">
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]295<a name="otherimprovements">Other Improvements</a>
296</div>
297
298<div class="doc_text">
299<p>New features include:
300</p>
301
302<ul>
Chris Lattner618a99f2008-06-05 06:57:39 +0000[diff] [blame]303<li>LLVM now builds with GCC 4.3.</li>
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame^]304<li>llvm2cpp tool has been folded into llc, use <tt>llc -march=cpp</tt></li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]305</ul>
306
307</div>
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]308
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]309<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]310<div class="doc_section">
311 <a name="portability">Portability and Supported Platforms</a>
312</div>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]313<!-- *********************************************************************** -->
314
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]315<div class="doc_text">
316
John Criswell64307722004-12-08 20:35:47 +0000[diff] [blame]317<p>LLVM is known to work on the following platforms:</p>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]318
319<ul>
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame^]320<li>Intel and AMD machines (IA32) running Red Hat Linux, Fedora Core and FreeBSD
Reid Spencer9803b402005-05-17 02:47:27 +0000[diff] [blame]321 (and probably other unix-like systems).</li>
Chris Lattner7422bce2008-02-06 06:30:34 +0000[diff] [blame]322<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]323 64-bit modes.</li>
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]324<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]325<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
326 support is available for native builds with Visual C++).</li>
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame^]327<li>Sun UltraSPARC workstations running Solaris 10.</li>
John Criswelld5234922005-05-13 20:28:15 +0000[diff] [blame]328<li>Alpha-based machines running Debian GNU/Linux.</li>
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame^]329<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]330</ul>
331
Chris Lattner618a99f2008-06-05 06:57:39 +0000[diff] [blame]332<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekee3e557e2004-05-09 05:28:35 +0000[diff] [blame]333to the machine and operating system on which it is built. However, minor
334porting may be required to get LLVM to work on new platforms. We welcome your
335portability patches and reports of successful builds or error messages.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]336
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]337</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]338
339<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]340<div class="doc_section">
341 <a name="knownproblems">Known Problems</a>
342</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]343<!-- *********************************************************************** -->
344
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]345<div class="doc_text">
346
347<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]348component. As new problems are discovered, they will be added to these
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]349sections. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]350href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]351there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]352
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]353</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]354
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]355<!-- ======================================================================= -->
356<div class="doc_subsection">
357 <a name="experimental">Experimental features included with this release</a>
358</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]359
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]360<div class="doc_text">
361
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]362<p>The following components of this LLVM release are either untested, known to
363be broken or unreliable, or are in early development. These components should
364not be relied on, and bugs should not be filed against them, but they may be
365useful 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]366components, please contact us on the <a
367href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]368
369<ul>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]370<li>The MSIL, IA64, Alpha, SPU, and MIPS backends are experimental.</li>
Chris Lattner7422bce2008-02-06 06:30:34 +0000[diff] [blame]371<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
372 value for this option.</li>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]373</ul>
374
375</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]376
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]377<!-- ======================================================================= -->
378<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]379 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]380</div>
381
382<div class="doc_text">
383
384<ul>
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]385<li>The X86 backend does not yet support all <a
386 href="http://llvm.org/PR879">inline assembly that uses the X86 floating
387 point stack</a>. It supports the 'f' and 't' constraints, but not 'u'.</li>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]388<li>The X86 backend generates inefficient floating point code when configured to
389 generate code for systems that don't have SSE2.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]390</ul>
391
392</div>
393
394<!-- ======================================================================= -->
395<div class="doc_subsection">
396 <a name="ppc-be">Known problems with the PowerPC back-end</a>
397</div>
398
399<div class="doc_text">
400
401<ul>
Nicolas Geoffray77d99502007-05-15 09:21:28 +0000[diff] [blame]402<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]403compilation, and lacks support for debug information.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]404</ul>
405
406</div>
407
408<!-- ======================================================================= -->
409<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]410 <a name="arm-be">Known problems with the ARM back-end</a>
411</div>
412
413<div class="doc_text">
414
415<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]416<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands47fc0a22007-09-26 15:59:54 +0000[diff] [blame]417processors, thumb programs can crash or produce wrong
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]418results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]419<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
420</li>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]421<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]422programs compiled with LLVM. Please use more recent versions of QEMU.</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]423</ul>
424
425</div>
426
427<!-- ======================================================================= -->
428<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]429 <a name="sparc-be">Known problems with the SPARC back-end</a>
430</div>
431
432<div class="doc_text">
433
434<ul>
435<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
436 support the 64-bit SPARC ABI (-m64).</li>
437</ul>
438
439</div>
440
441<!-- ======================================================================= -->
442<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]443 <a name="alpha-be">Known problems with the Alpha back-end</a>
444</div>
445
446<div class="doc_text">
447
448<ul>
449
450<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
451appropriate nops inserted to ensure restartability.</li>
452
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]453</ul>
454</div>
455
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]456<!-- ======================================================================= -->
457<div class="doc_subsection">
458 <a name="ia64-be">Known problems with the IA64 back-end</a>
459</div>
460
461<div class="doc_text">
462
463<ul>
464
465<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
466made where the argument is not 16-byte aligned, as required on IA64. (Strictly
467speaking this is not a bug in the IA64 back-end; it will also be encountered
468when building C++ programs using the C back-end.)</li>
469
470<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
471ABI compliant layout of v-tables</a>. In particular, it just stores function
472pointers instead of function descriptors in the vtable. This bug prevents
473mixing C++ code compiled with LLVM with C++ objects compiled by other C++
474compilers.</li>
475
476<li>There are a few ABI violations which will lead to problems when mixing LLVM
477output with code built with other compilers, particularly for floating-point
478programs.</li>
479
480<li>Defining vararg functions is not supported (but calling them is ok).</li>
481
Chris Lattner98a33492007-05-09 04:58:11 +0000[diff] [blame]482<li>The Itanium backend has bitrotted somewhat.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]483</ul>
484
485</div>
486
487<!-- ======================================================================= -->
488<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]489 <a name="c-be">Known problems with the C back-end</a>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]490</div>
491
492<div class="doc_text">
493
494<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]495<li><a href="http://llvm.org/PR802">The C backend has only basic support for
496 inline assembly code</a>.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000[diff] [blame]497<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
498 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
499 C++ code compiled with LLC or native compilers.</li>
Duncan Sandse09506a2008-02-10 13:40:55 +0000[diff] [blame]500<li>The C backend does not support all exception handling constructs.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]501</ul>
502
503</div>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]504
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]505
506<!-- ======================================================================= -->
507<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]508 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]509</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000[diff] [blame]510
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]511<!-- _______________________________________________________________________ -->
Chris Lattner5a8a7282003-12-14 05:03:43 +0000[diff] [blame]512<div class="doc_subsubsection">Bugs</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]513
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]514<div class="doc_text">
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]515
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]516<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
517Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]518llvmdev mailing list if you are interested.</p>
Chris Lattner44124232006-08-08 17:27:28 +0000[diff] [blame]519
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]520<p>The only major language feature of GCC not supported by llvm-gcc is
521 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
522 are only supported on some targets. For example, trampolines are only
523 supported on some targets, which are used when you take the address of a
524 nested function.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]525
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]526<p>If you run into GCC extensions which are not supported, please let us know.
527</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]528
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]529</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]530
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]531<!-- ======================================================================= -->
532<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]533 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]534</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]535
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]536<div class="doc_text">
537
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]538<p>The C++ front-end is considered to be fully
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]539tested and works for a number of non-trivial programs, including LLVM
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]540itself, Qt, Mozilla, etc.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]541
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]542<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]543<li>Exception handling works well on the X86 and PowerPC targets, including
544x86-64 darwin. This works when linking to a libstdc++ compiled by GCC. It is
545supported on x86-64 linux, but that is disabled by default in this release.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]546</ul>
Chris Lattner46ecf612003-10-07 22:14:37 +0000[diff] [blame]547
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]548</div>
549
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]550
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]551<!-- ======================================================================= -->
552<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]553 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]554</div>
555
556<div class="doc_text">
557The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
558technology and problems should be expected.
559<ul>
560<li>The Ada front-end currently only builds on x86-32. This is mainly due
561to lack of trampoline support (pointers to nested functions) on other platforms,
562however it <a href="http://llvm.org/PR2006">also fails to build on x86-64</a>
563which does support trampolines.</li>
564<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
565Workaround: configure with --disable-bootstrap.</li>
566<li>The c380004 and <a href="http://llvm.org/PR2010">c393010</a> ACATS tests
567fail (c380004 also fails with gcc-4.2 mainline).</li>
568<li>Many gcc specific Ada tests continue to crash the compiler.</li>
569<li>The -E binder option (exception backtraces)
570<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
571crashing if an exception is raised. Workaround: do not use -E.</li>
572<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
573or finish at a non-byte offset</a> in a record. Workaround: do not pack records
574or use representation clauses that result in a field of a non-discrete type
575starting or finishing in the middle of a byte.</li>
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame^]576<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers 'main'
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]577as generated by the Ada binder to be invalid</a>.
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame^]578Workaround: hand edit the file to use pointers for <tt>argv</tt> and <tt>envp</tt> rather than
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]579integers.</li>
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame^]580<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is ignored</a>.</li>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]581</ul>
582</div>
583
584<!-- ======================================================================= -->
585<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]586 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]587</div>
588
589<div class="doc_text">
590
591<ul>
592<li>The llvm-gcc 4.2 gfortran front-end supports a broad range of Fortran code, but does
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame^]593<a href="http://llvm.org/PR1971">not support <tt>EQUIVALENCE</tt> yet</a>.</li>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]594</ul>
595</div>
596
597
Chris Lattnerb62a5f02005-05-15 16:01:20 +0000[diff] [blame]598
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]599<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]600<div class="doc_section">
601 <a name="additionalinfo">Additional Information</a>
602</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]603<!-- *********************************************************************** -->
604
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]605<div class="doc_text">
606
Chris Lattnercb5596d2005-05-16 17:13:10 +0000[diff] [blame]607<p>A wide variety of additional information is available on the <a
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]608href="http://llvm.org">LLVM web page</a>, in particular in the <a
609href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]610contains versions of the API documentation which is up-to-date with the
611Subversion version of the source code.
Misha Brukman96158092005-03-30 19:14:24 +0000[diff] [blame]612You can access versions of these documents specific to this release by going
613into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]614
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]615<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]616us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]617lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]618
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]619</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]620
621<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]622
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]623<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]624<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000[diff] [blame]625 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]626 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
627 <a href="http://validator.w3.org/check/referer"><img
Chris Lattner458e79f2008-02-10 08:18:42 +0000[diff] [blame]628 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]629
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]630 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]631 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]632</address>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]633
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]634</body>
635</html>