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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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]12
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
35<p>This document contains the release notes for the LLVM compiler
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]36infrastructure, release 2.4. Here we describe the status of LLVM, including
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]37major improvements from the previous release and any known problems. All LLVM
38releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
39releases web site</a>.</p>
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
44href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
45list</a> is a good place to send them.</p>
46
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
60<div class="doc_text">
61
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]62<p>This is the fifteenth public release of the LLVM Compiler Infrastructure.
63It includes a large number of features and refinements from LLVM 2.3.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]64
65</div>
66
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]67<!-- Unfinished features in 2.4:
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]68 Machine LICM
69 Machine Sinking
70 LegalizeDAGTypes
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]71 llc -enable-value-prop, propagation of value info (sign/zero ext info) from
72 one MBB to another
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]73 -->
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]74
75 <!-- for announcement email:
76 mention dev mtg
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]77 Xcode 3.1 and 3.1.1.
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]78 -->
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]79
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]80<!--=========================================================================-->
81<div class="doc_subsection">
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]82<a name="changes">Major Changes in LLVM 2.4</a>
Chris Lattner41bf8e92008-02-10 07:04:35 +0000[diff] [blame]83</div>
84
85<div class="doc_text">
86
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]87<p>The LLVM IR generated by llvm-gcc now doesn't name instructions. Use the
88 instnamer pass if you want them.</p>
89
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]90<li>LoadVN and GCSE are completely gone.</li>
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]91
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]92
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]93<p>LLVM API Changes:</p>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]94
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]95<ul>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]96<li>....</li>
Daniel Dunbardcb129a2008-10-11 21:26:56 +0000[diff] [blame]97
98<li>... Attributes changes ... </li>
99
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]100<li>The <tt>DbgStopPointInst</tt> methods <tt>getDirectory</tt> and
101<tt>getFileName</tt> now return <tt>Value*</tt> instead of strings. These can be
102converted to strings using <tt>llvm::GetConstantStringInfo</tt> defined via
103"llvm/Analysis/ValueTracking.h".</li>
Daniel Dunbardcb129a2008-10-11 21:26:56 +0000[diff] [blame]104
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]105<li>API change: BinaryOperator::create -> Create (CmpInst, CastInst too)</li>
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]106<li>Various header files like "llvm/ADT/iterator" were given a .h suffix.
107 Change your code to #include "llvm/ADT/iterator.h" instead.</li>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]108
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]109</ul>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]110
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]111</div>
112
113<!--=========================================================================-->
114<div class="doc_subsection">
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]115<a name="otherprojects">Other LLVM Sub-Projects</a>
116</div>
117
118<div class="doc_text">
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]119<p>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]120The core LLVM 2.4 distribution currently consists of code from the core LLVM
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]121repository (which roughly contains the LLVM optimizer, code generators and
122supporting tools) and the llvm-gcc repository. In addition to this code, the
123LLVM Project includes other sub-projects that are in development. The two which
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]124are the most actively developed are the <a href="#clang">Clang Project</a> and
125<a href="#vmkit">vmkit Project</a>.
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]126</p>
127</div>
128
129<!--=========================================================================-->
130<div class="doc_subsubsection">
131<a name="vmkit">vmkit</a>
132</div>
133
134<div class="doc_text">
135<p>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]136The <a href="http://vmkit.llvm.org/">"vmkit" project</a> is an implementation of
137a JVM and a CLI Virtual Machines (Microsoft .NET is an
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]138implementation of the CLI) using the Just-In-Time compiler of LLVM.</p>
139
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]140<p>...</p>
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]141
142</div>
143
144<!--=========================================================================-->
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]145<div class="doc_subsubsection">
146<a name="clang">Clang</a>
147</div>
148
149<div class="doc_text">
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. Clang is continuing to make major strides forward in all
154areas. Its C and Objective-C parsing support is very solid, and the code
155generation support is far enough along to build many C applications. While not
156yet production quality, it is progressing very nicely. In addition, C++
157front-end work has started to make significant progress.</p>
158
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]159<p>Codegen progress/state
160</p>
161
162<p>
163<a href="http://clang.llvm.org/StaticAnalysis.html">static analysis tool</a>
164</p>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]165
166</div>
167
168
169<!-- *********************************************************************** -->
170<div class="doc_section">
171 <a name="whatsnew">What's New?</a>
172</div>
173<!-- *********************************************************************** -->
174
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]175<div class="doc_text">
176
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]177<p>LLVM 2.4 includes a huge number of bug fixes, performance tweaks and minor
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]178improvements. Some of the major improvements and new features are listed in
179this section.
180</p>
181</div>
182
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]183<!--=========================================================================-->
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]184<div class="doc_subsection">
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]185<a name="majorfeatures">Major New Features</a>
186</div>
187
188<div class="doc_text">
189
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]190<p>LLVM 2.4 includes several major new capabilities:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]191
192<ul>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]193<li>
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]194 <p>MRVs got generalized to FCAs. getresult is gone, ret with multiple values
195 is gone.</p>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]196 </li>
197
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]198<li><p>-O0 compile times overall much faster</p></li>
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]199
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]200<li><p>Attrs changes?</p></li>
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]201
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]202
203<li><p>Initial PIC16 port</p></li>
204
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]205<li><p> Support the rest of the atomic __sync builtins</p></li>
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]206
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]207<li><p>...</p></li>
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]208
Chris Lattner5ba16862008-02-10 08:18:42 +0000[diff] [blame]209</ul>
210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]211</div>
212
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]213
214<!--=========================================================================-->
215<div class="doc_subsection">
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]216<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]217</div>
218
219<div class="doc_text">
220
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]221<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]222for the C, C++, Objective-C, Ada, and Fortran front-ends.</p>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]223
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]224<p>
225<ul>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]226<li>...</li>
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]227
Gabor Greif0e49cc82008-06-09 06:06:18 +0000[diff] [blame]228</ul>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]229
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]230</div>
231
232
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]233<!--=========================================================================-->
234<div class="doc_subsection">
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]235<a name="coreimprovements">LLVM Core Improvements</a>
236</div>
237
238<div class="doc_text">
239<p>New features include:
240</p>
241
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]242<ul>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]243<li>vector shifts in the IR: no codegen support yet</li>
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]244<li>use diet patch landed: saved 15% IR memory footprint</li>
245<li>LLVM IR now directly represents "common" linkage, instead of
246 representing it as a form of weak linkage.</li>
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]247<li>DebugInfoBuilder</li>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]248<li>.ll printing format change: %3 = add i32 4, 2</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]249<li>...</li>
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]250</ul>
251
252</div>
253
254<!--=========================================================================-->
255<div class="doc_subsection">
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]256<a name="optimizer">Optimizer Improvements</a>
257</div>
258
259<div class="doc_text">
260
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]261<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]262LLVM 2.4 optimizers support a few major enhancements:</p>
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]263
264<ul>
265
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]266<li>GVN now does local PRE?</li>
267
268<li>Matthijs' Dead argument elimination rewrite</li>
269
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]270<li>Old-ADCE used control dependence and deleted output-free infinite loops.
271Added a new Loop deletion pass (for deleting output free provably-finite loops)
272and rewrote ADCE to be simpler faster, and not need control dependence.</li>
273
274<li>SparsePropagation framework for lattice-based dataflow solvers.</li>
275
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]276<li>Tail duplication was removed from the standard optimizer sequence.</li>
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]277
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]278<li>Various helper functions (ComputeMaskedBits, ComputeNumSignBits, etc) were
279pulled out of instcombine and put into a new ValueTracking.h file, where they
280can be reused by other passes.</li>
281
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]282<li>MarkModRef etc</li>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]283</ul>
284
285</div>
286
287<!--=========================================================================-->
288<div class="doc_subsection">
289<a name="codegen">Code Generator Improvements</a>
290</div>
291
292<div class="doc_text">
293
294<p>We put a significant amount of work into the code generator infrastructure,
295which allows us to implement more aggressive algorithms and make it run
296faster:</p>
297
298<ul>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]299<li>asm writers split out to their own library to avoid JITs having to link
300 them in.</li>
301<li>Big asm writer refactoring + TargetAsmInfo</li>
302<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]303<li>spiller to commute instructions in order to fold a reload</li>
304<li>Stack slot coloring?</li>
305<li>Live intervals renumbering? Is this useful to external people?</li>
306<li>'is as cheap as a move' instruction flag</li>
307<li>Improvements to selection dag viewing</li>
308<li>fast isel</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]309<li>Selection dag speedups</li>
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]310<li>asmwriter + raw_ostream -> fastah</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]311<li>...</li>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]312
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]313</ul>
314
315</div>
316
317
318<!--=========================================================================-->
319<div class="doc_subsection">
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]320<a name="x86specific">X86/X86-64 Specific Improvements</a>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]321</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]322
323<div class="doc_text">
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]324<p>New target-specific features include:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]325</p>
326
327<ul>
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]328<li>Exception handling is supported by default on Linux/x86-64.</li>
329<li>Position Independent Code (PIC) is now support on Linux/x86-64.</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]330<li>...</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]331
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]332</ul>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]333
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]334</div>
335
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]336<!--=========================================================================-->
337<div class="doc_subsection">
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]338<a name="targetspecific">Other Target Specific Improvements</a>
339</div>
340
341<div class="doc_text">
342<p>New target-specific features include:
343</p>
344
345<ul>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]346<li>MIPS floating point support?</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]347<li>....</li>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]348</ul>
349
350</div>
351
352
353
354<!--=========================================================================-->
355<div class="doc_subsection">
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]356<a name="otherimprovements">Other Improvements</a>
357</div>
358
359<div class="doc_text">
360<p>New features include:
361</p>
362
363<ul>
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]364<li>raw_ostream + formatting</li>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]365<li>Recycler + pool allocation stuff?</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]366<li>...</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]367</ul>
368
369</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]370
371<!-- *********************************************************************** -->
372<div class="doc_section">
373 <a name="portability">Portability and Supported Platforms</a>
374</div>
375<!-- *********************************************************************** -->
376
377<div class="doc_text">
378
379<p>LLVM is known to work on the following platforms:</p>
380
381<ul>
Gabor Greif5e75e652008-06-05 18:39:01 +0000[diff] [blame]382<li>Intel and AMD machines (IA32) running Red Hat Linux, Fedora Core and FreeBSD
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]383 (and probably other unix-like systems).</li>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]384<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]385 64-bit modes.</li>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]386<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]387<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
388 support is available for native builds with Visual C++).</li>
Gabor Greif5e75e652008-06-05 18:39:01 +0000[diff] [blame]389<li>Sun UltraSPARC workstations running Solaris 10.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]390<li>Alpha-based machines running Debian GNU/Linux.</li>
Gabor Greif5e75e652008-06-05 18:39:01 +0000[diff] [blame]391<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]392</ul>
393
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]394<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]395to the machine and operating system on which it is built. However, minor
396porting may be required to get LLVM to work on new platforms. We welcome your
397portability patches and reports of successful builds or error messages.</p>
398
399</div>
400
401<!-- *********************************************************************** -->
402<div class="doc_section">
403 <a name="knownproblems">Known Problems</a>
404</div>
405<!-- *********************************************************************** -->
406
407<div class="doc_text">
408
409<p>This section contains all known problems with the LLVM system, listed by
410component. As new problems are discovered, they will be added to these
411sections. If you run into a problem, please check the <a
412href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
413there isn't already one.</p>
414
415</div>
416
417<!-- ======================================================================= -->
418<div class="doc_subsection">
419 <a name="experimental">Experimental features included with this release</a>
420</div>
421
422<div class="doc_text">
423
424<p>The following components of this LLVM release are either untested, known to
425be broken or unreliable, or are in early development. These components should
426not be relied on, and bugs should not be filed against them, but they may be
427useful 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]428components, please contact us on the <a
429href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]430
431<ul>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]432<li>The MSIL, IA64, Alpha, SPU, and MIPS backends are experimental.</li>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]433<li>The llc "<tt>-filetype=asm</tt>" (the default) is the only supported
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]434 value for this option.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]435</ul>
436
437</div>
438
439<!-- ======================================================================= -->
440<div class="doc_subsection">
441 <a name="x86-be">Known problems with the X86 back-end</a>
442</div>
443
444<div class="doc_text">
445
446<ul>
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000[diff] [blame]447 <li>The X86 backend does not yet support
448 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
449 floating point stack</a>. It supports the 'f' and 't' constraints, but not
450 'u'.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]451 <li>The X86 backend generates inefficient floating point code when configured
452 to generate code for systems that don't have SSE2.</li>
Duncan Sands8b4f3772008-06-08 19:38:43 +0000[diff] [blame]453 <li>Win64 code generation wasn't widely tested. Everything should work, but we
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000[diff] [blame]454 expect small issues to happen. Also, llvm-gcc cannot build mingw64 runtime
455 currently due
456 to <a href="http://llvm.org/PR2255">several</a>
Chris Lattnerf06141a2008-06-08 23:12:47 +0000[diff] [blame]457 <a href="http://llvm.org/PR2257">bugs</a> due to lack of support for the
458 'u' inline assembly constraint and X87 floating point inline assembly.</li>
Dan Gohman3882ecb2008-06-08 23:05:11 +0000[diff] [blame]459 <li>The X86-64 backend does not yet support the LLVM IR instruction
460 <tt>va_arg</tt>. Currently, the llvm-gcc front-end supports variadic
461 argument constructs on X86-64 by lowering them manually.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]462</ul>
463
464</div>
465
466<!-- ======================================================================= -->
467<div class="doc_subsection">
468 <a name="ppc-be">Known problems with the PowerPC back-end</a>
469</div>
470
471<div class="doc_text">
472
473<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]474<li>The Linux PPC32/ABI support needs testing for the interpreter and static
475compilation, and lacks support for debug information.</li>
476</ul>
477
478</div>
479
480<!-- ======================================================================= -->
481<div class="doc_subsection">
482 <a name="arm-be">Known problems with the ARM back-end</a>
483</div>
484
485<div class="doc_text">
486
487<ul>
488<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]489processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]490results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
491<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
492</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]493<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly
494 execute
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]495programs compiled with LLVM. Please use more recent versions of QEMU.</li>
496</ul>
497
498</div>
499
500<!-- ======================================================================= -->
501<div class="doc_subsection">
502 <a name="sparc-be">Known problems with the SPARC back-end</a>
503</div>
504
505<div class="doc_text">
506
507<ul>
508<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
509 support the 64-bit SPARC ABI (-m64).</li>
510</ul>
511
512</div>
513
514<!-- ======================================================================= -->
515<div class="doc_subsection">
516 <a name="alpha-be">Known problems with the Alpha back-end</a>
517</div>
518
519<div class="doc_text">
520
521<ul>
522
523<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
524appropriate nops inserted to ensure restartability.</li>
525
526</ul>
527</div>
528
529<!-- ======================================================================= -->
530<div class="doc_subsection">
531 <a name="ia64-be">Known problems with the IA64 back-end</a>
532</div>
533
534<div class="doc_text">
535
536<ul>
Chris Lattnerf06141a2008-06-08 23:12:47 +0000[diff] [blame]537<li>The Itanium backend is highly experimental, and has a number of known
538 issues. We are looking for a maintainer for the Itanium backend. If you
539 are interested, please contact the llvmdev mailing list.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]540</ul>
541
542</div>
543
544<!-- ======================================================================= -->
545<div class="doc_subsection">
546 <a name="c-be">Known problems with the C back-end</a>
547</div>
548
549<div class="doc_text">
550
551<ul>
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]552<li><a href="http://llvm.org/PR802">The C backend has only basic support for
553 inline assembly code</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]554<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
555 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]556 C++ code compiled with llc or native compilers.</li>
Duncan Sandsbd0ad6e2008-02-10 13:40:55 +0000[diff] [blame]557<li>The C backend does not support all exception handling constructs.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]558</ul>
559
560</div>
561
562
563<!-- ======================================================================= -->
564<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]565 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]566</div>
567
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]568<div class="doc_text">
569
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]570<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
571Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]572llvmdev mailing list if you are interested.</p>
573
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]574<p>The only major language feature of GCC not supported by llvm-gcc is
575 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
576 are only supported on some targets. For example, trampolines are only
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]577 supported on some targets (these are used when you take the address of a
578 nested function).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]579
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]580<p>If you run into GCC extensions which are not supported, please let us know.
581</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]582
583</div>
584
585<!-- ======================================================================= -->
586<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]587 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]588</div>
589
590<div class="doc_text">
591
592<p>The C++ front-end is considered to be fully
593tested and works for a number of non-trivial programs, including LLVM
594itself, Qt, Mozilla, etc.</p>
595
596<ul>
Anton Korobeynikovd9a17932008-10-11 18:27:16 +0000[diff] [blame]597<li>Exception handling works well on the X86 and PowerPC targets. Currently
598 only linux and darwin targets are supported (both 32 and 64 bit).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]599</ul>
600
601</div>
602
603
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]604<!-- ======================================================================= -->
605<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]606 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]607</div>
608
609<div class="doc_text">
610The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
611technology and problems should be expected.
612<ul>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]613<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]614to lack of trampoline support (pointers to nested functions) on other platforms,
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]615however 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]616which does support trampolines.</li>
617<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
618Workaround: configure with --disable-bootstrap.</li>
619<li>The c380004 and <a href="http://llvm.org/PR2010">c393010</a> ACATS tests
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]620fail (c380004 also fails with gcc-4.2 mainline). When built at -O3, the
621<a href="http://llvm.org/PR2421">cxg2021</a> ACATS test also fails.</li>
622<li>Some gcc specific Ada tests continue to crash the compiler. The testsuite
623reports most tests as having failed even though they pass.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]624<li>The -E binder option (exception backtraces)
625<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
626crashing if an exception is raised. Workaround: do not use -E.</li>
627<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
628or finish at a non-byte offset</a> in a record. Workaround: do not pack records
629or use representation clauses that result in a field of a non-discrete type
630starting or finishing in the middle of a byte.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]631<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
632'main' as generated by the Ada binder to be invalid</a>.
633Workaround: hand edit the file to use pointers for <tt>argv</tt> and
634<tt>envp</tt> rather than integers.</li>
635<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
636ignored</a>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]637</ul>
638</div>
639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]640<!-- *********************************************************************** -->
641<div class="doc_section">
642 <a name="additionalinfo">Additional Information</a>
643</div>
644<!-- *********************************************************************** -->
645
646<div class="doc_text">
647
648<p>A wide variety of additional information is available on the <a
649href="http://llvm.org">LLVM web page</a>, in particular in the <a
650href="http://llvm.org/docs/">documentation</a> section. The web page also
651contains versions of the API documentation which is up-to-date with the
652Subversion version of the source code.
653You can access versions of these documents specific to this release by going
654into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
655
656<p>If you have any questions or comments about LLVM, please feel free to contact
657us via the <a href="http://llvm.org/docs/#maillist"> mailing
658lists</a>.</p>
659
660</div>
661
662<!-- *********************************************************************** -->
663
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