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Chris Lattner21e1b7a2011-12-13 17:55:30 +00007 <title>LLVM 3.1 Release Notes</title>
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9<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +000010
Chris Lattner21e1b7a2011-12-13 17:55:30 +000011<h1>LLVM 3.1 Release Notes</h1>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +000012
Jakub Staszakf8de54f2011-12-06 23:33:07 +000013<div>
14<img style="float:right" src="http://llvm.org/img/DragonSmall.png"
15 width="136" height="136" alt="LLVM Dragon Logo">
16</div>
Chris Lattner0e464a92010-03-17 04:02:39 +000017
Chris Lattner79c3fe12003-10-02 04:57:28 +000018<ol>
Misha Brukman500bc302003-11-22 00:38:41 +000019 <li><a href="#intro">Introduction</a></li>
Chris Lattner96a445e2008-10-13 18:01:01 +000020 <li><a href="#subproj">Sub-project Status Update</a></li>
Chris Lattner21e1b7a2011-12-13 17:55:30 +000021 <li><a href="#externalproj">External Projects Using LLVM 3.1</a></li>
22 <li><a href="#whatsnew">What's New in LLVM?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +000023 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Dan Gohman44aa9212008-10-14 16:23:02 +000024 <li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +000025 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +000026</ol>
27
Chris Lattner7911ce22004-05-23 21:07:27 +000028<div class="doc_author">
NAKAMURA Takumib9a33632011-04-09 02:13:37 +000029 <p>Written by the <a href="http://llvm.org/">LLVM Team</a></p>
Misha Brukman500bc302003-11-22 00:38:41 +000030</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000031
Chris Lattner21e1b7a2011-12-13 17:55:30 +000032<h1 style="color:red">These are in-progress notes for the upcoming LLVM 3.1
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000033release.<br>
34You may prefer the
Chris Lattner21e1b7a2011-12-13 17:55:30 +000035<a href="http://llvm.org/releases/3.0/docs/ReleaseNotes.html">LLVM 3.0
Dan Gohmanb44f6c62010-05-03 23:51:05 +000036Release Notes</a>.</h1>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000037
Chris Lattner79c3fe12003-10-02 04:57:28 +000038<!-- *********************************************************************** -->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +000039<h2>
Misha Brukman500bc302003-11-22 00:38:41 +000040 <a name="intro">Introduction</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +000041</h2>
Chris Lattner79c3fe12003-10-02 04:57:28 +000042<!-- *********************************************************************** -->
43
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +000044<div>
Misha Brukman500bc302003-11-22 00:38:41 +000045
Chris Lattnerf6662f92008-10-13 17:57:36 +000046<p>This document contains the release notes for the LLVM Compiler
Chris Lattner21e1b7a2011-12-13 17:55:30 +000047 Infrastructure, release 3.1. Here we describe the status of LLVM, including
Chris Lattner1ab8ce92011-11-27 18:47:37 +000048 major improvements from the previous release, improvements in various
49 subprojects of LLVM, and some of the current users of the code.
Bill Wendling7b7fa742011-10-26 18:46:16 +000050 All LLVM releases may be downloaded from
51 the <a href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +000052
Chris Lattner7506b1d2004-12-07 08:04:13 +000053<p>For more information about LLVM, including information about the latest
Bill Wendling7b7fa742011-10-26 18:46:16 +000054 release, please check out the <a href="http://llvm.org/">main LLVM web
55 site</a>. If you have questions or comments,
56 the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM
57 Developer's Mailing List</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +000058
Bill Wendling7b7fa742011-10-26 18:46:16 +000059<p>Note that if you are reading this file from a Subversion checkout or the main
60 LLVM web page, this document applies to the <i>next</i> release, not the
61 current one. To see the release notes for a specific release, please see the
62 <a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +000063
64</div>
Michael J. Spencer60f790c2011-11-28 18:20:09 +000065
66
Chris Lattner96a445e2008-10-13 18:01:01 +000067<!-- *********************************************************************** -->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +000068<h2>
Chris Lattner96a445e2008-10-13 18:01:01 +000069 <a name="subproj">Sub-project Status Update</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +000070</h2>
Chris Lattner96a445e2008-10-13 18:01:01 +000071<!-- *********************************************************************** -->
Chris Lattnerea34f642008-06-08 21:34:41 +000072
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +000073<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +000074
Chris Lattner21e1b7a2011-12-13 17:55:30 +000075<p>The LLVM 3.1 distribution currently consists of code from the core LLVM
Bill Wendling7b7fa742011-10-26 18:46:16 +000076 repository (which roughly includes the LLVM optimizers, code generators and
Chris Lattnerc343e312011-11-10 20:15:40 +000077 supporting tools), and the Clang repository. In
Bill Wendling7b7fa742011-10-26 18:46:16 +000078 addition to this code, the LLVM Project includes other sub-projects that are
79 in development. Here we include updates on these subprojects.</p>
Chris Lattner96a445e2008-10-13 18:01:01 +000080
Chris Lattner8348b472008-06-08 21:58:17 +000081<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +000082<h3>
Chris Lattnerfb97b2d2008-10-13 18:11:54 +000083<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +000084</h3>
Chris Lattner8348b472008-06-08 21:58:17 +000085
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +000086<div>
Chris Lattner8348b472008-06-08 21:58:17 +000087
Chris Lattner095539f2010-04-26 17:42:18 +000088<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
Bill Wendling7b7fa742011-10-26 18:46:16 +000089 C++, and Objective-C languages. Clang aims to provide a better user
90 experience through expressive diagnostics, a high level of conformance to
91 language standards, fast compilation, and low memory use. Like LLVM, Clang
92 provides a modular, library-based architecture that makes it suitable for
93 creating or integrating with other development tools. Clang is considered a
94 production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
Chris Lattner1ab8ce92011-11-27 18:47:37 +000095 (32- and 64-bit), and for Darwin/ARM targets.</p>
Chris Lattner61358ab2009-10-13 17:48:04 +000096
Chris Lattner21e1b7a2011-12-13 17:55:30 +000097<p>In the LLVM 3.1 time-frame, the Clang team has made many improvements:</p>
Douglas Gregorba087df2011-10-15 00:48:01 +000098<ul>
Seth Cantrellacc472a2012-05-08 23:34:38 +000099 <li>C++11 support is greatly expanded including lambdas, initializer lists, constexpr, user-defined literals, and atomics.</li>
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000100 <li>...</li>
Douglas Gregorba087df2011-10-15 00:48:01 +0000101</ul>
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000102
103 <p>For more details about the changes to Clang since the 2.9 release, see the
Chandler Carruthcc966de2011-11-29 00:32:43 +0000104<a href="http://clang.llvm.org/docs/ReleaseNotes.html">Clang release notes</a>
105</p>
Douglas Gregorba087df2011-10-15 00:48:01 +0000106
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000107
Duncan Sandsf3ba7af2011-04-06 08:07:40 +0000108<p>If Clang rejects your code but another compiler accepts it, please take a
Bill Wendling7b7fa742011-10-26 18:46:16 +0000109 look at the <a href="http://clang.llvm.org/compatibility.html">language
110 compatibility</a> guide to make sure this is not intentional or a known
111 issue.</p>
Bill Wendling741748a2008-10-27 09:27:33 +0000112
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000113</div>
114
115<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000116<h3>
Duncan Sands528a5102011-04-04 11:09:08 +0000117<a name="dragonegg">DragonEgg: GCC front-ends, LLVM back-end</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000118</h3>
Chris Lattner61358ab2009-10-13 17:48:04 +0000119
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000120<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000121<p><a href="http://dragonegg.llvm.org/">DragonEgg</a> is a
122 <a href="http://gcc.gnu.org/wiki/plugins">gcc plugin</a> that replaces GCC's
Duncan Sands5abd10a2012-05-11 19:59:43 +0000123 optimizers and code generators with LLVM's. It works with gcc-4.5 and gcc-4.6
124 (and partially with gcc-4.7), can target the x86-32/x86-64 and ARM processor
125 families, and has been successfully used on the Darwin, FreeBSD, KFreeBSD,
126 Linux and OpenBSD platforms. It fully supports Ada, C, C++ and Fortran. It
127 has partial support for Go, Java, Obj-C and Obj-C++.</p>
Duncan Sands749fd832010-04-02 09:23:15 +0000128
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000129<p>The 3.1 release has the following notable changes:</p>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000130
Chris Lattner1ab8ce92011-11-27 18:47:37 +0000131 <ul>
Duncan Sands77352c92011-11-10 18:44:29 +0000132
Duncan Sands5abd10a2012-05-11 19:59:43 +0000133 <li>Partial support for gcc-4.7. Ada support is poor, but other languages work
134 fairly well.</li>
135
136 <li>Support for ARM processors. Some essential gcc headers that are needed to
137 build DragonEgg for ARM are not installed by gcc. To work around this,
138 copy the missing headers from the gcc source tree.</li>
139
140 <li>Better optimization for Fortran by exploiting the fact that Fortran scalar
141 arguments have 'restrict' semantics.</li>
142
143 <li>Better optimization for all languages by passing information about type
144 aliasing and type ranges to the LLVM optimizers.</li>
145
146 <li>A regression test-suite was added.</li>
Duncan Sands77352c92011-11-10 18:44:29 +0000147
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000148</ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000149
150</div>
151
Chris Lattner75547712010-10-03 23:49:06 +0000152<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000153<h3>
Chris Lattner75547712010-10-03 23:49:06 +0000154<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000155</h3>
Chris Lattner75547712010-10-03 23:49:06 +0000156
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000157<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000158
159<p>The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
160 is a simple library that provides an implementation of the low-level
161 target-specific hooks required by code generation and other runtime
162 components. For example, when compiling for a 32-bit target, converting a
163 double to a 64-bit unsigned integer is compiled into a runtime call to the
164 "__fixunsdfdi" function. The compiler-rt library provides highly optimized
165 implementations of this and other low-level routines (some are 3x faster than
166 the equivalent libgcc routines).</p>
Chris Lattner75547712010-10-03 23:49:06 +0000167
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000168<p>....</p>
Chris Lattner75547712010-10-03 23:49:06 +0000169
170</div>
Chris Lattner61358ab2009-10-13 17:48:04 +0000171
172<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000173<h3>
Chris Lattnere07043c2010-09-29 05:30:03 +0000174<a name="lldb">LLDB: Low Level Debugger</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000175</h3>
Chris Lattnere07043c2010-09-29 05:30:03 +0000176
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000177<div>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000178
Chris Lattner9e896712011-11-27 18:53:41 +0000179<p>LLDB is a ground-up implementation of a command line debugger, as well as a
180 debugger API that can be used from other applications. LLDB makes use of the
181 Clang parser to provide high-fidelity expression parsing (particularly for
182 C++) and uses the LLVM JIT for target support.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000183
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000184<p>...</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000185
186</div>
187
188<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000189<h3>
Chris Lattnere07043c2010-09-29 05:30:03 +0000190<a name="libc++">libc++: C++ Standard Library</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000191</h3>
Chris Lattnere07043c2010-09-29 05:30:03 +0000192
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000193<div>
Chris Lattnere07043c2010-09-29 05:30:03 +0000194
Bill Wendling7b7fa742011-10-26 18:46:16 +0000195<p>Like compiler_rt, libc++ is now <a href="DeveloperPolicy.html#license">dual
196 licensed</a> under the MIT and UIUC license, allowing it to be used more
197 permissively.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000198
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000199<p>...</p>
David Chisnall553284e2011-11-26 10:56:17 +0000200
Chris Lattnere07043c2010-09-29 05:30:03 +0000201</div>
202
Chris Lattner3d6a80a2011-04-07 03:08:22 +0000203<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000204<h3>
Chris Lattner3d6a80a2011-04-07 03:08:22 +0000205<a name="vmkit">VMKit</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000206</h3>
Chris Lattner3d6a80a2011-04-07 03:08:22 +0000207
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000208<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000209
Nicolas Geoffray54d5df92011-11-10 23:37:56 +0000210 <p>The <a href="http://vmkit.llvm.org/">VMKit project</a> is an
211 implementation of a Java Virtual Machine (Java VM or JVM) that uses LLVM for
212 static and just-in-time compilation.
213
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000214 <p>In the LLVM 3.1 time-frame, VMKit has had significant improvements on both
Nicolas Geoffray54d5df92011-11-10 23:37:56 +0000215 runtime and startup performance:</p>
216
217 <ul>
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000218 <li>...</li>
Nicolas Geoffray54d5df92011-11-10 23:37:56 +0000219 </ul>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000220
Chris Lattner3d6a80a2011-04-07 03:08:22 +0000221</div>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000222
Tobias Grosser76213b82012-04-16 17:17:00 +0000223
224<!--=========================================================================-->
225<h3>
Tobias Grosser99a0b282012-04-16 17:18:49 +0000226<a name="Polly">Polly: Polyhedral Optimizer</a>
Tobias Grosser76213b82012-04-16 17:17:00 +0000227</h3>
228
229<div>
230
231 <p><a href="http://polly.llvm.org/">Polly</a> is an <em>experimental</em>
232 optimizer for data locality and parallelism. It currently provides high-level
233 loop optimizations and automatic parallelisation (using the OpenMP run time).
234 Work in the area of automatic SIMD and accelerator code generation was
235 started.
236
237 <p>Within the LLVM 3.1 time-frame there were the following highlights:</p>
238
239 <ul>
240 <li>Polly became an official LLVM project</li>
241 <li>Polly can be loaded directly into clang (Enabled by '-O3 -mllvm -polly'
242 )</li>
243 <li>An automatic scheduling optimizer (derived from <a
244 href="http://pluto-compiler.sourceforge.net/">Pluto</a>) was integrated. It
245 performs loop transformations to optimize for data-locality and parallelism.
246 The transformations include, but are not limited to interchange, fusion,
247 fission, skewing and tiling.
248 </li>
249 </ul>
250
251</div>
252
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000253</div>
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000254
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000255<!-- *********************************************************************** -->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000256<h2>
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000257 <a name="externalproj">External Open Source Projects Using LLVM 3.1</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000258</h2>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000259<!-- *********************************************************************** -->
260
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000261<div>
Chris Lattner61358ab2009-10-13 17:48:04 +0000262
263<p>An exciting aspect of LLVM is that it is used as an enabling technology for
264 a lot of other language and tools projects. This section lists some of the
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000265 projects that have already been updated to work with LLVM 3.1.</p>
Chris Lattner75547712010-10-03 23:49:06 +0000266
Bill Wendlingf8cfe2e2012-05-13 09:52:48 +0000267<h3>FAUST</h3>
268
269<div>
270
271<p>FAUST is a compiled language for real-time audio signal processing. The name
272 FAUST stands for Functional AUdio STream. Its programming model combines two
273 approaches: functional programming and block diagram composition. In addition
274 with the C, C++, Java, JavaScript output formats, the Faust compiler can
275 generate LLVM bitcode, and works with LLVM 2.7-3.1.</p>
276
277</div>
278
Bill Wendlingde86bea2012-05-11 21:42:37 +0000279<h3>Glasgow Haskell Compiler (GHC)</h3>
280
281<div>
282
283<p>GHC is an open source compiler and programming suite for Haskell, a lazy
284 functional programming language. It includes an optimizing static compiler
285 generating good code for a variety of platforms, together with an interactive
286 system for convenient, quick development.</p>
287
288<p>GHC 7.0 and onwards include an LLVM code generator, supporting LLVM 2.8 and
289 later.</p>
290
291</div>
292
293<h3>Pure</h3>
294
295<div>
296
Bill Wendling015d2ad2012-05-11 22:38:33 +0000297<p><a href="http://pure-lang.googlecode.com/">Pure</a> is an
298 algebraic/functional programming language based on term rewriting. Programs
299 are collections of equations which are used to evaluate expressions in a
300 symbolic fashion. The interpreter uses LLVM as a backend to JIT-compile Pure
301 programs to fast native code. Pure offers dynamic typing, eager and lazy
302 evaluation, lexical closures, a hygienic macro system (also based on term
303 rewriting), built-in list and matrix support (including list and matrix
304 comprehensions) and an easy-to-use interface to C and other programming
305 languages (including the ability to load LLVM bitcode modules, and inline C,
306 C++, Fortran and Faust code in Pure programs if the corresponding
307 LLVM-enabled compilers are installed).</p>
Bill Wendlingde86bea2012-05-11 21:42:37 +0000308
309<p>Pure version 0.54 has been tested and is known to work with LLVM 3.1 (and
310 continues to work with older LLVM releases >= 2.5).</p>
311
312</div>
Bill Wendling644ce532011-10-26 09:25:01 +0000313
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000314</div>
315
Chris Lattner8348b472008-06-08 21:58:17 +0000316<!-- *********************************************************************** -->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000317<h2>
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000318 <a name="whatsnew">What's New in LLVM 3.1?</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000319</h2>
Chris Lattner8348b472008-06-08 21:58:17 +0000320<!-- *********************************************************************** -->
321
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000322<div>
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000323
Chris Lattner61358ab2009-10-13 17:48:04 +0000324<p>This release includes a huge number of bug fixes, performance tweaks and
Bill Wendling7b7fa742011-10-26 18:46:16 +0000325 minor improvements. Some of the major improvements and new features are
326 listed in this section.</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000327
Chris Lattner914ce462010-04-22 06:28:20 +0000328<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000329<h3>
Chris Lattner252b83d2008-02-06 18:00:06 +0000330<a name="majorfeatures">Major New Features</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000331</h3>
Chris Lattner252b83d2008-02-06 18:00:06 +0000332
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000333<div>
Chris Lattner252b83d2008-02-06 18:00:06 +0000334
Chris Lattner1ab8ce92011-11-27 18:47:37 +0000335 <!-- Features that need text if they're finished for 3.1:
336 ARM EHABI
337 combiner-aa?
338 strong phi elim
339 loop dependence analysis
340 CorrelatedValuePropagation
341 lib/Transforms/IPO/MergeFunctions.cpp => consider for 3.1.
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000342 Integrated assembler on by default for arm/thumb?
343
Chris Lattner1ab8ce92011-11-27 18:47:37 +0000344 -->
345
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000346 <!-- Near dead:
Chris Lattnerdec23b62011-11-15 22:13:27 +0000347 Analysis/RegionInfo.h + Dom Frontiers
348 SparseBitVector: used in LiveVar.
Chris Lattner5a1731d2011-11-27 08:32:32 +0000349 llvm/lib/Archive - replace with lib object?
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000350 -->
Chris Lattner6a007d12011-11-25 20:33:27 +0000351
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000352<p>LLVM 3.1 includes several major changes and big features:</p>
Bill Wendlingbc5f6dd2011-10-26 18:33:01 +0000353
Chris Lattner791f77b2008-06-05 06:25:56 +0000354<ul>
Evan Cheng28681862011-12-14 22:57:45 +0000355 <li><a href="../tools/clang/docs/AddressSanitizer.html">AddressSanitizer</a>,
356 a fast memory error detector.</li>
357 <li><a href="CodeGenerator.html#machineinstrbundle">MachineInstr Bundles</a>,
358 Support to model instruction bundling / packing.</li>
Jim Grosbach6e6b8222012-02-23 23:52:06 +0000359 <li><a href="#armintegratedassembler">ARM Integrated Assembler</a>,
360 A full featured assembler and direct-to-object support for ARM.</li>
Chandler Carruth268fde42012-04-17 01:10:35 +0000361 <li><a href="#blockplacement">Basic Block Placement</a>
362 Probability driven basic block placement.</li>
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000363 <li>....</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000364</ul>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000365
Bill Wendlingbc5f6dd2011-10-26 18:33:01 +0000366</div>
367
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000368
Chris Lattner4f0fe432011-11-27 19:26:30 +0000369<!--=========================================================================-->
370<h3>
371<a name="coreimprovements">LLVM IR and Core Improvements</a>
372</h3>
373
374<div>
375
376<p>LLVM IR has several new features for better support of new targets and that
377 expose new optimization opportunities:</p>
378
Chris Lattner064caf92011-11-27 21:30:28 +0000379 <ul>
Dan Gohmaneb4c70b2011-12-20 01:10:56 +0000380 <li>IR support for half float</li>
Bill Wendling06d7e1b2012-02-06 21:59:44 +0000381 <li>IR support for vectors of pointers, including vector GEPs.</li>
Bill Wendling190ec9b2012-02-16 10:23:43 +0000382 <li>Module flags have been introduced. They convey information about the
383 module as a whole to LLVM subsystems.</li>
Rafael Espindola626c3462012-03-25 11:14:35 +0000384 <li>Loads can now have range metadata attached to them to describe the
Rafael Espindola692cd452012-03-24 19:02:32 +0000385 possible values being loaded.</li>
Chandler Carruthc76c94f2012-04-17 01:13:53 +0000386 <li>Inline cost heuristics have been completely overhauled and now closely
387 model constant propagation through call sites, disregard trivially dead
388 code costs, and can model C++ STL iterator patterns.</li>
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000389 <li>....</li>
Chris Lattner064caf92011-11-27 21:30:28 +0000390 </ul>
Andrew Trick5aab6382011-11-06 17:59:24 +0000391</div>
392
393<!--=========================================================================-->
394<h3>
Chris Lattneracce85d2008-02-10 07:46:44 +0000395<a name="optimizer">Optimizer Improvements</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000396</h3>
Chris Lattneracce85d2008-02-10 07:46:44 +0000397
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000398<div>
Chris Lattneracce85d2008-02-10 07:46:44 +0000399
Chris Lattner064caf92011-11-27 21:30:28 +0000400<p>In addition to many minor performance tweaks and bug fixes, this
Bill Wendling7b7fa742011-10-26 18:46:16 +0000401 release includes a few major enhancements and additions to the
402 optimizers:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000403
404<ul>
Brendon Cahoonff730392012-04-14 16:54:12 +0000405 <li>The loop unroll pass now is able to unroll loops with run-time trip counts.
406 This feature is turned off by default, and is enabled with the
407 <code>-unroll-runtime</code> flag.</li>
Hal Finkel9068bf52012-04-16 03:49:43 +0000408 <li>A new basic-block autovectorization pass is available. Pass
409 <code>-vectorize</code> to run this pass along with some associated
Hal Finkel12c10b32012-04-16 17:06:49 +0000410 post-vectorization cleanup passes. For more information, see the EuroLLVM
411 2012 slides: <a href="http://llvm.org/devmtg/2012-04-12/Slides/Hal_Finkel.pdf">
412 Autovectorization with LLVM</a>.</li>
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000413 <li>....</li>
Chris Lattner11b66112010-10-04 02:42:39 +0000414</ul>
415
Chris Lattner61358ab2009-10-13 17:48:04 +0000416</div>
Chris Lattner917cc712009-03-02 02:37:32 +0000417
Chris Lattner0b832202008-06-08 02:45:07 +0000418<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000419<h3>
Chris Lattner4ba2b652010-09-30 16:31:33 +0000420<a name="mc">MC Level Improvements</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000421</h3>
Chris Lattner4ba2b652010-09-30 16:31:33 +0000422
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000423<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000424
425<p>The LLVM Machine Code (aka MC) subsystem was created to solve a number of
426 problems in the realm of assembly, disassembly, object file format handling,
427 and a number of other related areas that CPU instruction-set level tools work
Chris Lattner2f206022011-11-27 22:03:34 +0000428 in. For more information, please see
429 the <a href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro
430 to the LLVM MC Project Blog Post</a>.</p>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000431
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000432<ul>
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000433 <li>....</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000434</ul>
435
NAKAMURA Takumi45c435a2011-04-05 08:24:22 +0000436</div>
Chris Lattner4ba2b652010-09-30 16:31:33 +0000437
Chris Lattner4ba2b652010-09-30 16:31:33 +0000438<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000439<h3>
Chris Lattner511433e2009-03-02 03:24:11 +0000440<a name="codegen">Target Independent Code Generator Improvements</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000441</h3>
Chris Lattner0b832202008-06-08 02:45:07 +0000442
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000443<div>
Chris Lattner0b832202008-06-08 02:45:07 +0000444
Bill Wendling190ec9b2012-02-16 10:23:43 +0000445<p>We have changed the way that the Type Legalizer legalizes vectors. The type
446 legalizer now attempts to promote integer elements. This enabled the
447 implementation of vector-select. Additionally, we see a performance boost on
448 workloads which use vectors of chars and shorts, since they are now promoted
449 to 32-bit types, which are better supported by the SIMD instruction set.
450 Floating point types are still widened as before.</p>
Nadav Rotem75597662011-12-20 08:02:50 +0000451
452
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000453<p>We have put a significant amount of work into the code generator
Bill Wendling7b7fa742011-10-26 18:46:16 +0000454 infrastructure, which allows us to implement more aggressive algorithms and
455 make it run faster:</p>
Chris Lattner0b832202008-06-08 02:45:07 +0000456
457<ul>
Jakob Stoklund Olesen9897c622011-12-19 16:53:40 +0000458 <li>TableGen can now synthesize register classes that are only needed to
Bill Wendling190ec9b2012-02-16 10:23:43 +0000459 represent combinations of constraints from instructions and sub-registers.
460 The synthetic register classes inherit most of their properties form their
461 closest user-defined super-class.</li>
Jakob Stoklund Olesend9e5c762012-01-05 00:26:49 +0000462 <li><code>MachineRegisterInfo</code> now allows the reserved registers to be
Bill Wendling190ec9b2012-02-16 10:23:43 +0000463 frozen when register allocation starts. Target hooks should use the
Nadav Rotemfdc309c2012-02-26 08:35:53 +0000464 <code>MRI-&gt;canReserveReg(FramePtr)</code> method to avoid accidentally
Bill Wendling190ec9b2012-02-16 10:23:43 +0000465 disabling frame pointer elimination during register allocation.</li>
Jakob Stoklund Olesen7739cad2012-01-16 19:22:00 +0000466 <li>A new kind of <code>MachineOperand</code> provides a compact
Bill Wendling190ec9b2012-02-16 10:23:43 +0000467 representation of large clobber lists on call instructions. The register
468 mask operand references a bit mask of preserved registers. Everything else
469 is clobbered.</li>
Chris Lattner84977642007-09-21 03:54:09 +0000470</ul>
Bill Wendling190ec9b2012-02-16 10:23:43 +0000471
Anshuman Dasgupta4b479552012-04-12 15:17:35 +0000472<p> We added new TableGen infrastructure to support bundling for
473 Very Long Instruction Word (VLIW) architectures. TableGen can now
474 automatically generate a deterministic finite automaton from a VLIW
475 target's schedule description which can be queried to determine
476 legal groupings of instructions in a bundle.</p>
477
Anshuman Dasgupta3c1ded22012-04-14 20:59:13 +0000478<p> We have added a new target independent VLIW packetizer based on the
Anshuman Dasguptacff391a2012-04-14 20:57:13 +0000479 DFA infrastructure to group machine instructions into bundles.</p>
480
Chris Lattner84977642007-09-21 03:54:09 +0000481</div>
482
Chandler Carruth268fde42012-04-17 01:10:35 +0000483<h4>
484<a name="blockplacement">Basic Block Placement</a>
485</h4>
486<div>
487<p>A probability based block placement and code layout algorithm was added to
488LLVM's code generator. This layout pass supports probabilities derived from
489static heuristics as well as source code annotations such as
490<code>__builtin_expect</code>.</p>
491</div>
492
Chris Lattner917cc712009-03-02 02:37:32 +0000493<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000494<h3>
Chris Lattner917cc712009-03-02 02:37:32 +0000495<a name="x86">X86-32 and X86-64 Target Improvements</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000496</h3>
Chris Lattner917cc712009-03-02 02:37:32 +0000497
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000498<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000499
500<p>New features and major changes in the X86 target include:</p>
Chris Lattner917cc712009-03-02 02:37:32 +0000501
502<ul>
Nadav Rotem75597662011-12-20 08:02:50 +0000503 <li>Bug fixes and improved support for AVX1</li>
504 <li>Support for AVX2 (still incomplete at this point)</li>
Jakob Stoklund Olesen26246612012-02-16 18:22:39 +0000505 <li>Call instructions use the new register mask operands for faster compile
506 times and better support for different calling conventions. The old WINCALL
507 instructions are no longer needed.</li>
NAKAMURA Takumi847307a2012-04-07 02:24:20 +0000508 <li>DW2 Exception Handling is enabled on Cygwin and MinGW.</li>
Bill Wendling59fc1662012-04-16 05:24:52 +0000509 <li>Support for implicit TLS model used with MS VC runtime</li>
Chris Lattner917cc712009-03-02 02:37:32 +0000510</ul>
511
Chris Lattner917cc712009-03-02 02:37:32 +0000512</div>
Chris Lattner84977642007-09-21 03:54:09 +0000513
514<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000515<h3>
Chris Lattner61358ab2009-10-13 17:48:04 +0000516<a name="ARM">ARM Target Improvements</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000517</h3>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000518
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000519<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000520
521<p>New features of the ARM target include:</p>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000522
523<ul>
Jakob Stoklund Olesenf5bb45f2011-12-16 16:07:41 +0000524 <li>The constant island pass now supports basic block and constant pool entry
Jim Grosbach6e6b8222012-02-23 23:52:06 +0000525 alignments greater than 4 bytes.</li>
526 <li>On Darwin, the ARM target now has a full-featured integrated assembler.
527 </li>
528</ul>
Chris Lattner7b95c382011-11-15 22:23:46 +0000529
Jim Grosbach6e6b8222012-02-23 23:52:06 +0000530<h4>
531<a name="armintegratedassembler">ARM Integrated Assembler</a>
532</h4>
533<div>
534<p>The ARM target now includes a full featured macro assembler, including
535direct-to-object module support for clang. The assembler is currently enabled
536by default for Darwin only pending testing and any additional necessary
537platform specific support for Linux.</p>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000538
Jim Grosbach6e6b8222012-02-23 23:52:06 +0000539<p>Full support is included for Thumb1, Thumb2 and ARM modes, along with
540subtarget and CPU specific extensions for VFP2, VFP3 and NEON.</p>
541
542<p>The assembler is Unified Syntax only (see ARM Architecural Reference Manual
543for details). While there is some, and growing, support for pre-unfied (divided)
544syntax, there are still significant gaps in that support.</p>
545</div>
NAKAMURA Takumi9c55f592012-03-27 11:25:16 +0000546
547</div>
Chris Lattner1efe27e2011-04-06 00:45:11 +0000548<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000549<h3>
Akira Hatanaka5381cbf2011-11-15 21:33:05 +0000550<a name="MIPS">MIPS Target Improvements</a>
551</h3>
552
553<div>
554
Chris Lattner1cc489b2011-11-27 22:12:32 +0000555<p>This release has seen major new work on just about every aspect of the MIPS
556 backend. Some of the major new features include:</p>
Akira Hatanaka5381cbf2011-11-15 21:33:05 +0000557
558<ul>
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000559 <li>....</li>
Akira Hatanaka5381cbf2011-11-15 21:33:05 +0000560</ul>
561</div>
Chris Lattner7b95c382011-11-15 22:23:46 +0000562
563<!--=========================================================================-->
564<h3>
Chris Lattner1efe27e2011-04-06 00:45:11 +0000565<a name="OtherTS">Other Target Specific Improvements</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000566</h3>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000567
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000568<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000569
Tony Linthicume05e55d2012-04-13 19:09:44 +0000570<p>Support for Qualcomm's Hexagon VLIW processor has been added.</p>
571
Chris Lattner1efe27e2011-04-06 00:45:11 +0000572<ul>
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000573 <li>....</li>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000574
Chris Lattnerd6cc2c22011-11-27 22:36:22 +0000575
Chris Lattner1efe27e2011-04-06 00:45:11 +0000576</ul>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000577
Chris Lattner1efe27e2011-04-06 00:45:11 +0000578</div>
Chris Lattner77d29b12008-06-05 08:02:49 +0000579
580<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000581<h3>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000582<a name="changes">Major Changes and Removed Features</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000583</h3>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000584
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000585<div>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000586
Bill Wendling2626dba2011-08-03 22:18:20 +0000587<p>If you're already an LLVM user or developer with out-of-tree changes based on
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000588 LLVM 3.1, this section lists some "gotchas" that you may run into upgrading
Bill Wendling2626dba2011-08-03 22:18:20 +0000589 from the previous release.</p>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000590
591<ul>
Bill Wendling190ec9b2012-02-16 10:23:43 +0000592 <li>LLVM 3.1 removes support for reading LLVM 2.9 bitcode files. Going
593 forward, we aim for all future versions of LLVM to read bitcode files and
594 <tt>.ll</tt> files produced by LLVM 3.0 and later.</li>
595 <li>The <tt>unwind</tt> instruction is now gone. With the introduction of the
596 new exception handling system in LLVM 3.0, the <tt>unwind</tt> instruction
597 became obsolete.</li>
Joerg Sonnenbergerdba86d82012-04-26 20:10:07 +0000598 <li>LLVM 3.0 and earlier automatically added the returns_twice fo functions
599 like setjmp based on the name. This functionality was removed in 3.1.
600 This affects Clang users, if -ffreestanding is used.</li>
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000601 <li>....</li>
Devang Patelb34dd132008-10-14 20:03:43 +0000602</ul>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000603
Chris Lattnerf6662f92008-10-13 17:57:36 +0000604</div>
605
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000606<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000607<h3>
Chris Lattner1efe27e2011-04-06 00:45:11 +0000608<a name="api_changes">Internal API Changes</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000609</h3>
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000610
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000611<div>
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000612
Chris Lattner1efe27e2011-04-06 00:45:11 +0000613<p>In addition, many APIs have changed in this release. Some of the major
Bill Wendling16005252011-08-02 06:20:17 +0000614 LLVM API changes are:</p>
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000615
616<ul>
Nick Lewycky98a92d12012-03-21 22:58:28 +0000617 <li>Target specific options have been moved from global variables to members
618 on the new <code>TargetOptions</code> class, which is local to each
619 <code>TargetMachine</code>. As a consequence, the associated flags will
620 no longer be accepted by <tt>clang -mllvm</tt>. This includes:
621<ul>
Nick Lewycky8a618a22012-03-23 00:56:26 +0000622<li><code>llvm::PrintMachineCode</code></li>
623<li><code>llvm::NoFramePointerElim</code></li>
624<li><code>llvm::NoFramePointerElimNonLeaf</code></li>
625<li><code>llvm::DisableFramePointerElim(const MachineFunction &)</code></li>
626<li><code>llvm::LessPreciseFPMADOption</code></li>
627<li><code>llvm::LessPrecideFPMAD()</code></li>
628<li><code>llvm::NoExcessFPPrecision</code></li>
629<li><code>llvm::UnsafeFPMath</code></li>
630<li><code>llvm::NoInfsFPMath</code></li>
631<li><code>llvm::NoNaNsFPMath</code></li>
632<li><code>llvm::HonorSignDependentRoundingFPMathOption</code></li>
633<li><code>llvm::HonorSignDependentRoundingFPMath()</code></li>
634<li><code>llvm::UseSoftFloat</code></li>
635<li><code>llvm::FloatABIType</code></li>
636<li><code>llvm::NoZerosInBSS</code></li>
637<li><code>llvm::JITExceptionHandling</code></li>
638<li><code>llvm::JITEmitDebugInfo</code></li>
639<li><code>llvm::JITEmitDebugInfoToDisk</code></li>
640<li><code>llvm::GuaranteedTailCallOpt</code></li>
641<li><code>llvm::StackAlignmentOverride</code></li>
642<li><code>llvm::RealignStack</code></li>
643<li><code>llvm::DisableJumpTables</code></li>
644<li><code>llvm::EnableFastISel</code></li>
645<li><code>llvm::getTrapFunctionName()</code></li>
646<li><code>llvm::EnableSegmentedStacks</code></li>
Nick Lewycky98a92d12012-03-21 22:58:28 +0000647</ul></li>
Duncan Sandse747fad2012-04-15 18:03:49 +0000648 <li>The MDBuilder class has been added to simplify the creation of
649 metadata.</li>
Chris Lattner21e1b7a2011-12-13 17:55:30 +0000650 <li>....</li>
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000651</ul>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000652
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000653</div>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000654
Nadav Rotemfdc309c2012-02-26 08:35:53 +0000655<!--=========================================================================-->
656<h3>
657<a name="tools_changes">Tools Changes</a>
658</h3>
659
660<div>
661
662<p>In addition, some tools have changed in this release. Some of the changes
663 are:</p>
664
665
666<ul>
667 <li>llvm-stress is a command line tool for generating random .ll files to fuzz
668 different LLVM components. </li>
Michael J. Spencer75338092012-04-19 19:27:54 +0000669 <li>llvm-ld has been removed. Use llvm-link or Clang instead.</li>
Nadav Rotemfdc309c2012-02-26 08:35:53 +0000670 <li>....</li>
671</ul>
672
673<ul>
674 <li>....</li>
675</ul>
676
677</div>
678
Gregory Szorcca347492012-05-12 21:12:22 +0000679
680<!--=========================================================================-->
681<h3>
682<a name="python">Python Bindings</a>
683</h3>
684
685<div>
686
687<p>Officially supported Python bindings have been added! Feature support is far
688from complete. The current bindings support interfaces to:</p>
689<ul>
690 <li>Object File Interface</li>
691 <li>Disassembler</li>
692</ul>
693
694<p>Using the Object File Interface, it is possible to inspect binary object files.
695Think of it as a Python version of readelf or llvm-objdump.</p>
696
697<p>Support for additional features is currently being developed by community
698contributors. If you are interested in shaping the direction of the Python
699bindings, please express your intent on IRC or the developers list.</p>
700
701</div>
702
Nadav Rotemfdc309c2012-02-26 08:35:53 +0000703</div>
704
Chris Lattner79c3fe12003-10-02 04:57:28 +0000705<!-- *********************************************************************** -->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000706<h2>
Misha Brukman500bc302003-11-22 00:38:41 +0000707 <a name="knownproblems">Known Problems</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000708</h2>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000709<!-- *********************************************************************** -->
710
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000711<div>
Misha Brukman500bc302003-11-22 00:38:41 +0000712
Chris Lattner70e22012011-11-27 19:38:20 +0000713<p>LLVM is generally a production quality compiler, and is used by a broad range
714 of applications and shipping in many products. That said, not every
715 subsystem is as mature as the aggregate, particularly the more obscure
716 targets. If you run into a problem, please check the <a
717 href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
718 there isn't already one or ask on the <a
719 href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev
720 list</a>.</p>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000721
Chris Lattner70e22012011-11-27 19:38:20 +0000722 <p>Known problem areas include:</p>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000723
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000724<ul>
Chris Lattner70e22012011-11-27 19:38:20 +0000725 <li>The Alpha, Blackfin, CellSPU, MSP430, PTX, SystemZ and
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000726 XCore backends are experimental, and the Alpha, Blackfin and SystemZ
727 targets have already been removed from mainline.</li>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000728
Chris Lattner70e22012011-11-27 19:38:20 +0000729 <li>The integrated assembler, disassembler, and JIT is not supported by
730 several targets. If an integrated assembler is not supported, then a
731 system assembler is required. For more details, see the <a
732 href="CodeGenerator.html#targetfeatures">Target Features Matrix</a>.
733 </li>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000734
Chris Lattner70e22012011-11-27 19:38:20 +0000735 <li>The C backend has numerous problems and is not being actively maintained.
736 Depending on it for anything serious is not advised.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000737</ul>
738
739</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000740
Chris Lattner79c3fe12003-10-02 04:57:28 +0000741<!-- *********************************************************************** -->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000742<h2>
Misha Brukman500bc302003-11-22 00:38:41 +0000743 <a name="additionalinfo">Additional Information</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000744</h2>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000745<!-- *********************************************************************** -->
746
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000747<div>
Misha Brukman500bc302003-11-22 00:38:41 +0000748
Bill Wendling7b7fa742011-10-26 18:46:16 +0000749<p>A wide variety of additional information is available on
750 the <a href="http://llvm.org/">LLVM web page</a>, in particular in
751 the <a href="http://llvm.org/docs/">documentation</a> section. The web page
752 also contains versions of the API documentation which is up-to-date with the
753 Subversion version of the source code. You can access versions of these
754 documents specific to this release by going into the "<tt>llvm/doc/</tt>"
755 directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000756
Misha Brukman500bc302003-11-22 00:38:41 +0000757<p>If you have any questions or comments about LLVM, please feel free to contact
Bill Wendling7b7fa742011-10-26 18:46:16 +0000758 us via the <a href="http://llvm.org/docs/#maillist"> mailing lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000759
Misha Brukman500bc302003-11-22 00:38:41 +0000760</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000761
762<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000763
Misha Brukman500bc302003-11-22 00:38:41 +0000764<hr>
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Misha Brukman2061e892003-11-22 01:23:39 +0000770
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000771 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000772 Last modified: $Date$
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