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Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]7 <title>LLVM 2.4 Release Notes</title>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]8</head>
9<body>
10
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]11<div class="doc_title">LLVM 2.4 Release Notes</div>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]12
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]13<ol>
14 <li><a href="#intro">Introduction</a></li>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]15 <li><a href="#changes">Major Changes and Sub-project Status</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]16 <li><a href="#whatsnew">What's New?</a></li>
17 <li><a href="GettingStarted.html">Installation Instructions</a></li>
18 <li><a href="#portability">Portability and Supported Platforms</a></li>
19 <li><a href="#knownproblems">Known Problems</a>
20 <li><a href="#additionalinfo">Additional Information</a></li>
21</ol>
22
23<div class="doc_author">
24 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
25</div>
26
27<!-- *********************************************************************** -->
28<div class="doc_section">
29 <a name="intro">Introduction</a>
30</div>
31<!-- *********************************************************************** -->
32
33<div class="doc_text">
34
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame^]35<p>This document contains the release notes for the LLVM Compiler
36Infrastructure, release 2.4. Here we describe the status of LLVM, including
37major improvements from the previous release and significant known problems.
38All LLVM releases may be downloaded from the <a
39href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]40
41<p>For more information about LLVM, including information about the latest
42release, please check out the <a href="http://llvm.org/">main LLVM
43web site</a>. If you have questions or comments, the <a
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame^]44href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's Mailing
45List</a> is a good place to send them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]46
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]47<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]48main LLVM web page, this document applies to the <i>next</i> release, not the
49current one. To see the release notes for a specific releases, please see the
50<a href="http://llvm.org/releases/">releases page</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]51
52</div>
53
54<!-- *********************************************************************** -->
55<div class="doc_section">
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]56 <a name="changes">Major Changes and Sub-project Status</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]57</div>
58<!-- *********************************************************************** -->
59
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame^]60<p>If you're already an LLVM user, this section lists some "gotchas" that you
61may run into upgrading from the previous release. It also includes some status
62updates on subprojects of LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]63
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame^]64<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]65
66</div>
67
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]68<!-- Unfinished features in 2.4:
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]69 Machine LICM
70 Machine Sinking
71 LegalizeDAGTypes
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]72 llc -enable-value-prop, propagation of value info (sign/zero ext info) from
73 one MBB to another
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]74 -->
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]75
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]76 <!-- for announcement email:
77 mention dev mtg
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]78 Xcode 3.1 and 3.1.1.
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]79 -->
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]80
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]81<!--=========================================================================-->
82<div class="doc_subsection">
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]83<a name="otherprojects">Other LLVM Sub-Projects</a>
84</div>
85
86<div class="doc_text">
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]87<p>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]88The core LLVM 2.4 distribution currently consists of code from the core LLVM
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]89repository (which roughly contains the LLVM optimizer, code generators and
90supporting tools) and the llvm-gcc repository. In addition to this code, the
91LLVM Project includes other sub-projects that are in development. The two which
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]92are the most actively developed are the <a href="#clang">Clang Project</a> and
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]93<a href="#vmkit">vmkit Project</a>.
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]94</p>
95</div>
96
97<!--=========================================================================-->
98<div class="doc_subsubsection">
99<a name="vmkit">vmkit</a>
100</div>
101
102<div class="doc_text">
103<p>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]104The <a href="http://vmkit.llvm.org/">"vmkit" project</a> is an implementation of
105a JVM and a CLI Virtual Machines (Microsoft .NET is an
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]106implementation of the CLI) using the Just-In-Time compiler of LLVM.</p>
107
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]108<p>...</p>
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]109
110</div>
111
112<!--=========================================================================-->
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]113<div class="doc_subsubsection">
114<a name="clang">Clang</a>
115</div>
116
117<div class="doc_text">
118
119<p>The <a href="http://clang.llvm.org/">Clang project</a> is an effort to build
120a set of new 'LLVM native' front-end technologies for the LLVM optimizer
121and code generator. Clang is continuing to make major strides forward in all
122areas. Its C and Objective-C parsing support is very solid, and the code
123generation support is far enough along to build many C applications. While not
124yet production quality, it is progressing very nicely. In addition, C++
125front-end work has started to make significant progress.</p>
126
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]127<p>Codegen progress/state
128</p>
129
130<p>
131<a href="http://clang.llvm.org/StaticAnalysis.html">static analysis tool</a>
132</p>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]133
134</div>
135
136
137<!-- *********************************************************************** -->
138<div class="doc_section">
139 <a name="whatsnew">What's New?</a>
140</div>
141<!-- *********************************************************************** -->
142
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]143<div class="doc_text">
144
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame^]145<p>This release includes a huge number of bug fixes, performance tweaks and
146minor improvements. Some of the major improvements and new features are listed
147in this section.
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]148</p>
149</div>
150
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]151<!--=========================================================================-->
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]152<div class="doc_subsection">
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]153<a name="majorfeatures">Major New Features</a>
154</div>
155
156<div class="doc_text">
157
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]158<p>LLVM 2.4 includes several major new capabilities:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]159
160<ul>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]161<li>
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]162 <p>MRVs got generalized to FCAs. getresult is gone, ret with multiple values
163 is gone.</p>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]164 </li>
165
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]166<li><p>-O0 compile times overall much faster</p></li>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]167
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]168<li><p>Attrs changes?</p></li>
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]169
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]170
171<li><p>Initial PIC16 port</p></li>
172
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]173<li><p> Support the rest of the atomic __sync builtins</p></li>
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]174
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]175<li><p>...</p></li>
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]176
Chris Lattner5ba16862008-02-10 08:18:42 +0000[diff] [blame]177</ul>
178
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]179</div>
180
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]181
182<!--=========================================================================-->
183<div class="doc_subsection">
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]184<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]185</div>
186
187<div class="doc_text">
188
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]189<p>LLVM 2.4 fully supports the llvm-gcc 4.2 front-end, and includes support
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]190for the C, C++, Objective-C, Ada, and Fortran front-ends.</p>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]191
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]192<p>
193<ul>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]194<li>...</li>
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]195
Gabor Greif0e49cc82008-06-09 06:06:18 +0000[diff] [blame]196</ul>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]197
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]198</div>
199
200
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]201<!--=========================================================================-->
202<div class="doc_subsection">
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]203<a name="coreimprovements">LLVM Core Improvements</a>
204</div>
205
206<div class="doc_text">
207<p>New features include:
208</p>
209
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]210<ul>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]211<li>vector shifts in the IR: no codegen support yet</li>
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]212<li>use diet patch landed: saved 15% IR memory footprint</li>
213<li>LLVM IR now directly represents "common" linkage, instead of
214 representing it as a form of weak linkage.</li>
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]215<li>DebugInfoBuilder</li>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]216<li>.ll printing format change: %3 = add i32 4, 2</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]217<li>...</li>
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]218</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]219
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]220</div>
221
222<!--=========================================================================-->
223<div class="doc_subsection">
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]224<a name="optimizer">Optimizer Improvements</a>
225</div>
226
227<div class="doc_text">
228
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]229<p>In addition to a huge array of bug fixes and minor performance tweaks, the
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]230LLVM 2.4 optimizers support a few major enhancements:</p>
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]231
232<ul>
233
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]234<li>GVN now does local PRE?</li>
235
236<li>Matthijs' Dead argument elimination rewrite</li>
237
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]238<li>Old-ADCE used control dependence and deleted output-free infinite loops.
239Added a new Loop deletion pass (for deleting output free provably-finite loops)
240and rewrote ADCE to be simpler faster, and not need control dependence.</li>
241
242<li>SparsePropagation framework for lattice-based dataflow solvers.</li>
243
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]244<li>Tail duplication was removed from the standard optimizer sequence.</li>
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]245
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]246<li>Various helper functions (ComputeMaskedBits, ComputeNumSignBits, etc) were
247pulled out of instcombine and put into a new ValueTracking.h file, where they
248can be reused by other passes.</li>
249
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]250<li>MarkModRef etc</li>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]251</ul>
252
253</div>
254
255<!--=========================================================================-->
256<div class="doc_subsection">
257<a name="codegen">Code Generator Improvements</a>
258</div>
259
260<div class="doc_text">
261
262<p>We put a significant amount of work into the code generator infrastructure,
263which allows us to implement more aggressive algorithms and make it run
264faster:</p>
265
266<ul>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]267<li>asm writers split out to their own library to avoid JITs having to link
268 them in.</li>
269<li>Big asm writer refactoring + TargetAsmInfo</li>
270<li>2-addr pass and coalescer can now remat trivial insts to avoid a copy.</li>
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]271<li>spiller to commute instructions in order to fold a reload</li>
272<li>Stack slot coloring?</li>
273<li>Live intervals renumbering? Is this useful to external people?</li>
274<li>'is as cheap as a move' instruction flag</li>
275<li>Improvements to selection dag viewing</li>
276<li>fast isel</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]277<li>Selection dag speedups</li>
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]278<li>asmwriter + raw_ostream -> fastah</li>
Chris Lattner72c8a252008-10-13 17:12:51 +0000[diff] [blame]279<li>Partitioned Boolean Quadratic Programming (PBQP) based register
280allocator.</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]281<li>...</li>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]282
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]283</ul>
284
285</div>
286
287
288<!--=========================================================================-->
289<div class="doc_subsection">
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]290<a name="x86specific">X86/X86-64 Specific Improvements</a>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]291</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]292
293<div class="doc_text">
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]294<p>New target-specific features include:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]295</p>
296
297<ul>
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]298<li>Exception handling is supported by default on Linux/x86-64.</li>
Duncan Sandsd8745a92008-10-13 17:32:15 +0000[diff] [blame]299<li>Position Independent Code (PIC) is now supported on Linux/x86-64.</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]300<li>...</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]301
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]302</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]303
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]304</div>
305
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]306<!--=========================================================================-->
307<div class="doc_subsection">
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]308<a name="targetspecific">Other Target Specific Improvements</a>
309</div>
310
311<div class="doc_text">
312<p>New target-specific features include:
313</p>
314
315<ul>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]316<li>MIPS floating point support?</li>
Duncan Sandsd8745a92008-10-13 17:32:15 +0000[diff] [blame]317<li>PowerPC now supports trampolines.</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]318<li>....</li>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]319</ul>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]320
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]321</div>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]322
323
324<!--=========================================================================-->
325<div class="doc_subsection">
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]326<a name="otherimprovements">Other Improvements</a>
327</div>
328
329<div class="doc_text">
330<p>New features include:
331</p>
332
333<ul>
Mikhail Glushenkovcc2d3012008-10-13 02:46:01 +0000[diff] [blame]334<li><tt>llvmc2</tt> (the generic compiler driver) gained plugin
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]335 support. It is now easier to experiment with <tt>llvmc2</tt> and
336 build your own tools based on it. </li>
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]337<li>raw_ostream + formatting</li>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]338<li>Recycler + pool allocation stuff?</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]339<li>...</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]340</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]341
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]342</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]343
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame^]344<!--=========================================================================-->
345<div class="doc_subsection">
346<a name="changes">Major Changes and Removed Features</a>
347</div>
348
349<div class="doc_text">
350
351<p>The LLVM IR generated by llvm-gcc now doesn't name instructions. Use the
352 instnamer pass if you want them.</p>
353
354<li>LoadVN and GCSE are completely gone.</li>
355
356
357<p>LLVM API Changes:</p>
358
359<ul>
360
361<li>... Attributes changes ... </li>
362
363<li>The <tt>DbgStopPointInst</tt> methods <tt>getDirectory</tt> and
364<tt>getFileName</tt> now return <tt>Value*</tt> instead of strings. These can be
365converted to strings using <tt>llvm::GetConstantStringInfo</tt> defined via
366"llvm/Analysis/ValueTracking.h".</li>
367
368<li>API change: BinaryOperator::create -> Create (CmpInst, CastInst too)</li>
369<li>Various header files like "llvm/ADT/iterator" were given a .h suffix.
370 Change your code to #include "llvm/ADT/iterator.h" instead.</li>
371
372</ul>
373
374</div>
375
376
377
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]378<!-- *********************************************************************** -->
379<div class="doc_section">
380 <a name="portability">Portability and Supported Platforms</a>
381</div>
382<!-- *********************************************************************** -->
383
384<div class="doc_text">
385
386<p>LLVM is known to work on the following platforms:</p>
387
388<ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]389<li>Intel and AMD machines (IA32) running Red Hat Linux, Fedora Core and FreeBSD
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]390 (and probably other unix-like systems).</li>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]391<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]392 64-bit modes.</li>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]393<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]394<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
395 support is available for native builds with Visual C++).</li>
Gabor Greif5e75e652008-06-05 18:39:01 +0000[diff] [blame]396<li>Sun UltraSPARC workstations running Solaris 10.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]397<li>Alpha-based machines running Debian GNU/Linux.</li>
Gabor Greif5e75e652008-06-05 18:39:01 +0000[diff] [blame]398<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]399</ul>
400
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]401<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]402to the machine and operating system on which it is built. However, minor
403porting may be required to get LLVM to work on new platforms. We welcome your
404portability patches and reports of successful builds or error messages.</p>
405
406</div>
407
408<!-- *********************************************************************** -->
409<div class="doc_section">
410 <a name="knownproblems">Known Problems</a>
411</div>
412<!-- *********************************************************************** -->
413
414<div class="doc_text">
415
416<p>This section contains all known problems with the LLVM system, listed by
417component. As new problems are discovered, they will be added to these
418sections. If you run into a problem, please check the <a
419href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
420there isn't already one.</p>
421
422</div>
423
424<!-- ======================================================================= -->
425<div class="doc_subsection">
426 <a name="experimental">Experimental features included with this release</a>
427</div>
428
429<div class="doc_text">
430
431<p>The following components of this LLVM release are either untested, known to
432be broken or unreliable, or are in early development. These components should
433not be relied on, and bugs should not be filed against them, but they may be
434useful to some people. In particular, if you would like to work on one of these
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]435components, please contact us on the <a
436href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]437
438<ul>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]439<li>The MSIL, IA64, Alpha, SPU, and MIPS backends are experimental.</li>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]440<li>The llc "<tt>-filetype=asm</tt>" (the default) is the only supported
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]441 value for this option.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]442</ul>
443
444</div>
445
446<!-- ======================================================================= -->
447<div class="doc_subsection">
448 <a name="x86-be">Known problems with the X86 back-end</a>
449</div>
450
451<div class="doc_text">
452
453<ul>
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000[diff] [blame]454 <li>The X86 backend does not yet support
455 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
456 floating point stack</a>. It supports the 'f' and 't' constraints, but not
457 'u'.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]458 <li>The X86 backend generates inefficient floating point code when configured
459 to generate code for systems that don't have SSE2.</li>
Duncan Sands8b4f3772008-06-08 19:38:43 +0000[diff] [blame]460 <li>Win64 code generation wasn't widely tested. Everything should work, but we
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000[diff] [blame]461 expect small issues to happen. Also, llvm-gcc cannot build mingw64 runtime
462 currently due
463 to <a href="http://llvm.org/PR2255">several</a>
Chris Lattnerf06141a2008-06-08 23:12:47 +0000[diff] [blame]464 <a href="http://llvm.org/PR2257">bugs</a> due to lack of support for the
465 'u' inline assembly constraint and X87 floating point inline assembly.</li>
Dan Gohman3882ecb2008-06-08 23:05:11 +0000[diff] [blame]466 <li>The X86-64 backend does not yet support the LLVM IR instruction
467 <tt>va_arg</tt>. Currently, the llvm-gcc front-end supports variadic
468 argument constructs on X86-64 by lowering them manually.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]469</ul>
470
471</div>
472
473<!-- ======================================================================= -->
474<div class="doc_subsection">
475 <a name="ppc-be">Known problems with the PowerPC back-end</a>
476</div>
477
478<div class="doc_text">
479
480<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]481<li>The Linux PPC32/ABI support needs testing for the interpreter and static
482compilation, and lacks support for debug information.</li>
483</ul>
484
485</div>
486
487<!-- ======================================================================= -->
488<div class="doc_subsection">
489 <a name="arm-be">Known problems with the ARM back-end</a>
490</div>
491
492<div class="doc_text">
493
494<ul>
495<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]496processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]497results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
498<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
499</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]500<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly
501 execute
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]502programs compiled with LLVM. Please use more recent versions of QEMU.</li>
503</ul>
504
505</div>
506
507<!-- ======================================================================= -->
508<div class="doc_subsection">
509 <a name="sparc-be">Known problems with the SPARC back-end</a>
510</div>
511
512<div class="doc_text">
513
514<ul>
515<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
516 support the 64-bit SPARC ABI (-m64).</li>
517</ul>
518
519</div>
520
521<!-- ======================================================================= -->
522<div class="doc_subsection">
523 <a name="alpha-be">Known problems with the Alpha back-end</a>
524</div>
525
526<div class="doc_text">
527
528<ul>
529
530<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
531appropriate nops inserted to ensure restartability.</li>
532
533</ul>
534</div>
535
536<!-- ======================================================================= -->
537<div class="doc_subsection">
538 <a name="ia64-be">Known problems with the IA64 back-end</a>
539</div>
540
541<div class="doc_text">
542
543<ul>
Chris Lattnerf06141a2008-06-08 23:12:47 +0000[diff] [blame]544<li>The Itanium backend is highly experimental, and has a number of known
545 issues. We are looking for a maintainer for the Itanium backend. If you
546 are interested, please contact the llvmdev mailing list.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]547</ul>
548
549</div>
550
551<!-- ======================================================================= -->
552<div class="doc_subsection">
553 <a name="c-be">Known problems with the C back-end</a>
554</div>
555
556<div class="doc_text">
557
558<ul>
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]559<li><a href="http://llvm.org/PR802">The C backend has only basic support for
560 inline assembly code</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]561<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
562 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]563 C++ code compiled with llc or native compilers.</li>
Duncan Sandsbd0ad6e2008-02-10 13:40:55 +0000[diff] [blame]564<li>The C backend does not support all exception handling constructs.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]565</ul>
566
567</div>
568
569
570<!-- ======================================================================= -->
571<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]572 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]573</div>
574
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]575<div class="doc_text">
576
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]577<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
578Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]579llvmdev mailing list if you are interested.</p>
580
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]581<p>The only major language feature of GCC not supported by llvm-gcc is
582 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
583 are only supported on some targets. For example, trampolines are only
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]584 supported on some targets (these are used when you take the address of a
585 nested function).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]586
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]587<p>If you run into GCC extensions which are not supported, please let us know.
588</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]589
590</div>
591
592<!-- ======================================================================= -->
593<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]594 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]595</div>
596
597<div class="doc_text">
598
599<p>The C++ front-end is considered to be fully
600tested and works for a number of non-trivial programs, including LLVM
601itself, Qt, Mozilla, etc.</p>
602
603<ul>
Anton Korobeynikovd9a17932008-10-11 18:27:16 +0000[diff] [blame]604<li>Exception handling works well on the X86 and PowerPC targets. Currently
605 only linux and darwin targets are supported (both 32 and 64 bit).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]606</ul>
607
608</div>
609
610
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]611<!-- ======================================================================= -->
612<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]613 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]614</div>
615
616<div class="doc_text">
617The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
618technology and problems should be expected.
619<ul>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]620<li>The Ada front-end currently only builds on X86-32. This is mainly due
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]621to lack of trampoline support (pointers to nested functions) on other platforms,
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]622however it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]623which does support trampolines.</li>
624<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
625Workaround: configure with --disable-bootstrap.</li>
Duncan Sands2dbc2e82008-10-13 17:27:23 +0000[diff] [blame]626<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
627and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
628(c380004 also fails with gcc-4.2 mainline).</li>
629<li>Some gcc specific Ada tests continue to crash the compiler.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]630<li>The -E binder option (exception backtraces)
631<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
632crashing if an exception is raised. Workaround: do not use -E.</li>
633<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
634or finish at a non-byte offset</a> in a record. Workaround: do not pack records
635or use representation clauses that result in a field of a non-discrete type
636starting or finishing in the middle of a byte.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]637<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
638'main' as generated by the Ada binder to be invalid</a>.
639Workaround: hand edit the file to use pointers for <tt>argv</tt> and
640<tt>envp</tt> rather than integers.</li>
641<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
642ignored</a>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]643</ul>
644</div>
645
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]646<!-- *********************************************************************** -->
647<div class="doc_section">
648 <a name="additionalinfo">Additional Information</a>
649</div>
650<!-- *********************************************************************** -->
651
652<div class="doc_text">
653
654<p>A wide variety of additional information is available on the <a
655href="http://llvm.org">LLVM web page</a>, in particular in the <a
656href="http://llvm.org/docs/">documentation</a> section. The web page also
657contains versions of the API documentation which is up-to-date with the
658Subversion version of the source code.
659You can access versions of these documents specific to this release by going
660into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
661
662<p>If you have any questions or comments about LLVM, please feel free to contact
663us via the <a href="http://llvm.org/docs/#maillist"> mailing
664lists</a>.</p>
665
666</div>
667
668<!-- *********************************************************************** -->
669
670<hr>
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