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Chris Lattnerbe2e1b52011-03-10 07:43:44 +00008 <title>LLVM 2.9 Release Notes</title>
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10<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +000011
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000012<div class="doc_title">LLVM 2.9 Release Notes</div>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +000013
Chris Lattner0e464a92010-03-17 04:02:39 +000014<img align=right src="http://llvm.org/img/DragonSmall.png"
Gabor Greifee2187a2010-04-22 10:21:43 +000015 width="136" height="136" alt="LLVM Dragon Logo">
Chris Lattner0e464a92010-03-17 04:02:39 +000016
Chris Lattner79c3fe12003-10-02 04:57:28 +000017<ol>
Misha Brukman500bc302003-11-22 00:38:41 +000018 <li><a href="#intro">Introduction</a></li>
Chris Lattner96a445e2008-10-13 18:01:01 +000019 <li><a href="#subproj">Sub-project Status Update</a></li>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000020 <li><a href="#externalproj">External Projects Using LLVM 2.9</a></li>
21 <li><a href="#whatsnew">What's New in LLVM 2.9?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +000022 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Dan Gohman44aa9212008-10-14 16:23:02 +000023 <li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +000024 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +000025</ol>
26
Chris Lattner7911ce22004-05-23 21:07:27 +000027<div class="doc_author">
Dan Gohman44aa9212008-10-14 16:23:02 +000028 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Misha Brukman500bc302003-11-22 00:38:41 +000029</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000030
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000031<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.9
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000032release.<br>
33You may prefer the
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000034<a href="http://llvm.org/releases/2.8/docs/ReleaseNotes.html">LLVM 2.8
Dan Gohmanb44f6c62010-05-03 23:51:05 +000035Release Notes</a>.</h1>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000036
Chris Lattner79c3fe12003-10-02 04:57:28 +000037<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +000038<div class="doc_section">
39 <a name="intro">Introduction</a>
40</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000041<!-- *********************************************************************** -->
42
Misha Brukman500bc302003-11-22 00:38:41 +000043<div class="doc_text">
44
Chris Lattnerf6662f92008-10-13 17:57:36 +000045<p>This document contains the release notes for the LLVM Compiler
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000046Infrastructure, release 2.9. Here we describe the status of LLVM, including
Chris Lattnerf6662f92008-10-13 17:57:36 +000047major improvements from the previous release and significant known problems.
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +000048All LLVM releases may be downloaded from the <a
Chris Lattnerf6662f92008-10-13 17:57:36 +000049href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +000050
Chris Lattner7506b1d2004-12-07 08:04:13 +000051<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +000052release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +000053web site</a>. If you have questions or comments, the <a
Chris Lattnerc66bfef2010-03-17 04:41:49 +000054href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's
55Mailing List</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +000056
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +000057<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner84977642007-09-21 03:54:09 +000058main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greiffa933f82008-10-14 11:00:32 +000059current one. To see the release notes for a specific release, please see the
Chris Lattner84977642007-09-21 03:54:09 +000060<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +000061
62</div>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000063
64<!-- NOTE: last release for llvm-gcc -->
Chris Lattner79c3fe12003-10-02 04:57:28 +000065
Chris Lattner61358ab2009-10-13 17:48:04 +000066<!--
67Almost dead code.
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000068 lib/Transforms/IPO/MergeFunctions.cpp => consider for 3.0.
Chris Lattner61358ab2009-10-13 17:48:04 +000069-->
70
71
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000072<!-- Features that need text if they're finished for 3.0:
Chris Lattner914ce462010-04-22 06:28:20 +000073 combiner-aa?
Chris Lattner61358ab2009-10-13 17:48:04 +000074 strong phi elim
Chris Lattner61358ab2009-10-13 17:48:04 +000075 loop dependence analysis
Chris Lattner885b6612010-08-28 16:33:36 +000076 TBAA
Chris Lattnere07043c2010-09-29 05:30:03 +000077 CorrelatedValuePropagation
Chris Lattneracce85d2008-02-10 07:46:44 +000078 -->
Chris Lattnere07043c2010-09-29 05:30:03 +000079
Chris Lattner96a445e2008-10-13 18:01:01 +000080<!-- *********************************************************************** -->
81<div class="doc_section">
82 <a name="subproj">Sub-project Status Update</a>
Chris Lattnerea34f642008-06-08 21:34:41 +000083</div>
Chris Lattner96a445e2008-10-13 18:01:01 +000084<!-- *********************************************************************** -->
Chris Lattnerea34f642008-06-08 21:34:41 +000085
86<div class="doc_text">
Chris Lattner8348b472008-06-08 21:58:17 +000087<p>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000088The LLVM 2.9 distribution currently consists of code from the core LLVM
Chris Lattner61358ab2009-10-13 17:48:04 +000089repository (which roughly includes the LLVM optimizers, code generators
90and supporting tools), the Clang repository and the llvm-gcc repository. In
91addition to this code, the LLVM Project includes other sub-projects that are in
92development. Here we include updates on these subprojects.
Bill Wendling63d8c552009-03-02 04:28:57 +000093</p>
Chris Lattner96a445e2008-10-13 18:01:01 +000094
Chris Lattner8348b472008-06-08 21:58:17 +000095</div>
96
Chris Lattner96a445e2008-10-13 18:01:01 +000097
Chris Lattner8348b472008-06-08 21:58:17 +000098<!--=========================================================================-->
Chris Lattner96a445e2008-10-13 18:01:01 +000099<div class="doc_subsection">
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000100<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000101</div>
102
103<div class="doc_text">
104
Chris Lattner095539f2010-04-26 17:42:18 +0000105<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
106C++, and Objective-C languages. Clang aims to provide a better user experience
107through expressive diagnostics, a high level of conformance to language
108standards, fast compilation, and low memory use. Like LLVM, Clang provides a
109modular, library-based architecture that makes it suitable for creating or
110integrating with other development tools. Clang is considered a
Chris Lattnere07043c2010-09-29 05:30:03 +0000111production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
112(32- and 64-bit), and for darwin-arm targets.</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000113
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000114<p>In the LLVM 2.9 time-frame, the Clang team has made many improvements:</p>
Bill Wendling741748a2008-10-27 09:27:33 +0000115
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000116<ul>
117</ul>
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000118</div>
119
120<!--=========================================================================-->
121<div class="doc_subsection">
122<a name="clangsa">Clang Static Analyzer</a>
123</div>
124
125<div class="doc_text">
126
Chris Lattner8cdd7932010-04-22 06:38:11 +0000127<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a>
128 project is an effort to use static source code analysis techniques to
129 automatically find bugs in C and Objective-C programs (and hopefully <a
130 href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the
131 future</a>!). The tool is very good at finding bugs that occur on specific
132 paths through code, such as on error conditions.</p>
Chris Lattnercc042612008-10-14 00:52:49 +0000133
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000134<p>The LLVM 2.9 release...
Chris Lattner8cdd7932010-04-22 06:38:11 +0000135</p>
Chris Lattner8348b472008-06-08 21:58:17 +0000136
137</div>
138
Chris Lattner96a445e2008-10-13 18:01:01 +0000139<!--=========================================================================-->
140<div class="doc_subsection">
Duncan Sands749fd832010-04-02 09:23:15 +0000141<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
Chris Lattner61358ab2009-10-13 17:48:04 +0000142</div>
143
144<div class="doc_text">
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000145NOTE: This should be written to be self-contained without referencing llvm-gcc.
146
Chris Lattner61358ab2009-10-13 17:48:04 +0000147<p>
Duncan Sands749fd832010-04-02 09:23:15 +0000148<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000149gcc-4.5. Unlike llvm-gcc, dragonegg in theory does not require any gcc-4.5
150modifications whatsoever (currently one small patch is needed) thanks to the
151new <a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>.
152DragonEgg is a gcc plugin that makes gcc-4.5 use the LLVM optimizers and code
153generators instead of gcc's, just like with llvm-gcc.
Duncan Sands749fd832010-04-02 09:23:15 +0000154</p>
155
156<p>
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000157DragonEgg is still a work in progress, but it is able to compile a lot of code,
158for example all of gcc, LLVM and clang. Currently Ada, C, C++ and Fortran work
159well, while all other languages either don't work at all or only work poorly.
160For the moment only the x86-32 and x86-64 targets are supported, and only on
161linux and darwin (darwin may need additional gcc patches).
Duncan Sands749fd832010-04-02 09:23:15 +0000162</p>
163
164<p>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000165The 2.9 release has the following notable changes:
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000166<ul>
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000167</ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000168
169</div>
170
Chris Lattner75547712010-10-03 23:49:06 +0000171<!--=========================================================================-->
172<div class="doc_subsection">
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000173<a name="vmkit">VMKit: JVM Virtual Machine Implementation</a>
Chris Lattner75547712010-10-03 23:49:06 +0000174</div>
175
176<div class="doc_text">
177<p>
178The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
179a Java Virtual Machine (Java VM or JVM) that uses LLVM for static and
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000180just-in-time compilation.
181
182UPDATE.
Chris Lattner75547712010-10-03 23:49:06 +0000183</p>
184</div>
185
186<!--=========================================================================-->
187<div class="doc_subsection">
188<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
189</div>
190
191<div class="doc_text">
192<p>
193The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
194is a simple library that provides an implementation of the low-level
195target-specific hooks required by code generation and other runtime components.
196For example, when compiling for a 32-bit target, converting a double to a 64-bit
197unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
198function. The compiler-rt library provides highly optimized implementations of
199this and other low-level routines (some are 3x faster than the equivalent
200libgcc routines).</p>
201
202<p>
203All of the code in the compiler-rt project is available under the standard LLVM
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000204License, a "BSD-style" license.
205
206NEW: MIT License as well.
207
208New in LLVM 2.9, UPDATE</p>
Chris Lattner75547712010-10-03 23:49:06 +0000209
210</div>
Chris Lattner61358ab2009-10-13 17:48:04 +0000211
212<!--=========================================================================-->
213<div class="doc_subsection">
Chris Lattnere07043c2010-09-29 05:30:03 +0000214<a name="lldb">LLDB: Low Level Debugger</a>
215</div>
216
217<div class="doc_text">
218<p>
Chris Lattner75547712010-10-03 23:49:06 +0000219<a href="http://lldb.llvm.org/">LLDB</a> is a brand new member of the LLVM
220umbrella of projects. LLDB is a next generation, high-performance debugger. It
221is built as a set of reusable components which highly leverage existing
222libraries in the larger LLVM Project, such as the Clang expression parser, the
223LLVM disassembler and the LLVM JIT.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000224
225<p>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000226LLDB is in early development and not included as part of the LLVM 2.9 release,
227UPDATE!
228
229<!--
Chris Lattner75547712010-10-03 23:49:06 +0000230but is mature enough to support basic debugging scenarios on Mac OS X in C,
231Objective-C and C++. We'd really like help extending and expanding LLDB to
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000232support new platforms, new languages, new architectures, and new features.-->
Chris Lattnere07043c2010-09-29 05:30:03 +0000233</p>
234
235</div>
236
237<!--=========================================================================-->
238<div class="doc_subsection">
239<a name="libc++">libc++: C++ Standard Library</a>
240</div>
241
242<div class="doc_text">
243<p>
Tobias Grossercdce44b2010-10-06 21:07:30 +0000244<a href="http://libcxx.llvm.org/">libc++</a> is another new member of the LLVM
Chris Lattner75547712010-10-03 23:49:06 +0000245family. It is an implementation of the C++ standard library, written from the
246ground up to specifically target the forthcoming C++'0X standard and focus on
247delivering great performance.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000248
249<p>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000250As of the LLVM 2.9 release, UPDATE!
251
252<!--libc++ is virtually feature complete, but would
Chris Lattner75547712010-10-03 23:49:06 +0000253benefit from more testing and better integration with Clang++. It is also
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000254looking forward to the C++ committee finalizing the C++'0x standard.-->
Chris Lattnere07043c2010-09-29 05:30:03 +0000255</p>
256
257</div>
258
Chris Lattner61358ab2009-10-13 17:48:04 +0000259
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000260
261<!--=========================================================================-->
262<div class="doc_subsection">
263<a name="klee">KLEE: A Symbolic Execution Virtual Machine</a>
264</div>
265
266<div class="doc_text">
267<p>
268<a href="http://klee.llvm.org/">KLEE</a> is a symbolic execution framework for
269programs in LLVM bitcode form. KLEE tries to symbolically evaluate "all" paths
270through the application and records state transitions that lead to fault
271states. This allows it to construct testcases that lead to faults and can even
272be used to verify some algorithms.
273</p>
274
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000275<p>UPDATE!</p>
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000276
277</div>
278
279
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000280<!-- *********************************************************************** -->
281<div class="doc_section">
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000282 <a name="externalproj">External Open Source Projects Using LLVM 2.9</a>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000283</div>
284<!-- *********************************************************************** -->
285
Chris Lattner61358ab2009-10-13 17:48:04 +0000286<div class="doc_text">
287
288<p>An exciting aspect of LLVM is that it is used as an enabling technology for
289 a lot of other language and tools projects. This section lists some of the
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000290 projects that have already been updated to work with LLVM 2.9.</p>
Chris Lattner7c8e7962010-04-26 17:38:10 +0000291</div>
292
Chris Lattner75547712010-10-03 23:49:06 +0000293
294
Chris Lattnere0518442010-10-01 06:34:49 +0000295
Chris Lattner8348b472008-06-08 21:58:17 +0000296<!-- *********************************************************************** -->
297<div class="doc_section">
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000298 <a name="whatsnew">What's New in LLVM 2.9?</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000299</div>
300<!-- *********************************************************************** -->
301
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000302<div class="doc_text">
303
Chris Lattner61358ab2009-10-13 17:48:04 +0000304<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattnerf6662f92008-10-13 17:57:36 +0000305minor improvements. Some of the major improvements and new features are listed
306in this section.
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000307</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000308
Chris Lattner914ce462010-04-22 06:28:20 +0000309</div>
310
311<!--=========================================================================-->
312<div class="doc_subsection">
Chris Lattner252b83d2008-02-06 18:00:06 +0000313<a name="majorfeatures">Major New Features</a>
314</div>
315
316<div class="doc_text">
317
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000318<p>LLVM 2.9 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000319
320<ul>
Chris Lattner8170c102008-02-10 08:18:42 +0000321</ul>
Chris Lattnerdc910082010-03-17 06:41:58 +0000322
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000323</div>
324
Chris Lattner84977642007-09-21 03:54:09 +0000325<!--=========================================================================-->
326<div class="doc_subsection">
Chris Lattner917cc712009-03-02 02:37:32 +0000327<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000328</div>
329
330<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000331<p>LLVM IR has several new features for better support of new targets and that
332expose new optimization opportunities:</p>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000333
Chris Lattner791f77b2008-06-05 06:25:56 +0000334<ul>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000335</ul>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000336
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000337</div>
338
339<!--=========================================================================-->
340<div class="doc_subsection">
Chris Lattneracce85d2008-02-10 07:46:44 +0000341<a name="optimizer">Optimizer Improvements</a>
342</div>
343
344<div class="doc_text">
345
Chris Lattner61358ab2009-10-13 17:48:04 +0000346<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattnerf3013872008-10-13 21:50:36 +0000347release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000348
349<ul>
Rafael Espindolaa26f36c2011-03-18 04:07:44 +0000350 <li>TBAA.</li>
351 <li>LTO has been improved to use MC for parsing inline asm and now
352 can build large programs like Firefox 4 on both OS X and Linux.</li>
Chris Lattner11b66112010-10-04 02:42:39 +0000353</ul>
354
355<!--
356<p>In addition to these features that are done in 2.8, there is preliminary
357 support in the release for Type Based Alias Analysis
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000358 Preliminary work on TBAA but not usable in 2.8.
359 New CorrelatedValuePropagation pass, not on by default in 2.8 yet.
Chris Lattner11b66112010-10-04 02:42:39 +0000360-->
Chris Lattner917cc712009-03-02 02:37:32 +0000361
Chris Lattner61358ab2009-10-13 17:48:04 +0000362</div>
Chris Lattner917cc712009-03-02 02:37:32 +0000363
Chris Lattner0b832202008-06-08 02:45:07 +0000364<!--=========================================================================-->
365<div class="doc_subsection">
Chris Lattner4ba2b652010-09-30 16:31:33 +0000366<a name="mc">MC Level Improvements</a>
367</div>
368
369<div class="doc_text">
370<p>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000371The LLVM Machine Code (aka MC) subsystem was created to solve a number
Chris Lattner4ba2b652010-09-30 16:31:33 +0000372of problems in the realm of assembly, disassembly, object file format handling,
373and a number of other related areas that CPU instruction-set level tools work
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000374in.</p>
375
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000376<ul>
Rafael Espindolaa26f36c2011-03-18 04:07:44 +0000377 <li>MC is now used by default for ELF systems on x86 and
378 x86-64.</li>
379 <li>MC supports and CodeGen uses the <tt>.loc</tt> directives for
380 producing line number debug info. This produces more compact line
381 tables.</li>
382 <li>MC supports the <tt>.cfi_*</tt> directives for producing DWARF
383 frame information, but it is still not used by CodeGen by default.</li>
384 <li>COFF support?</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000385</ul>
386
387<p>For more information, please see the <a
Chris Lattner4ba2b652010-09-30 16:31:33 +0000388href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
389LLVM MC Project Blog Post</a>.
390</p>
391
Chris Lattner4ba2b652010-09-30 16:31:33 +0000392</div>
393
394
Chris Lattner4ba2b652010-09-30 16:31:33 +0000395<!--=========================================================================-->
396<div class="doc_subsection">
Chris Lattner511433e2009-03-02 03:24:11 +0000397<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner0b832202008-06-08 02:45:07 +0000398</div>
399
400<div class="doc_text">
401
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000402<p>We have put a significant amount of work into the code generator
403infrastructure, which allows us to implement more aggressive algorithms and make
404it run faster:</p>
Chris Lattner0b832202008-06-08 02:45:07 +0000405
406<ul>
Chris Lattner3bdcda12010-10-04 03:58:12 +0000407<!-- SplitKit -->
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000408FastISel for ARM.
Chris Lattner84977642007-09-21 03:54:09 +0000409</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000410</div>
411
Chris Lattner917cc712009-03-02 02:37:32 +0000412<!--=========================================================================-->
413<div class="doc_subsection">
414<a name="x86">X86-32 and X86-64 Target Improvements</a>
415</div>
416
417<div class="doc_text">
Chris Lattner7714c912010-10-04 04:39:25 +0000418<p>New features and major changes in the X86 target include:
Chris Lattner917cc712009-03-02 02:37:32 +0000419</p>
420
421<ul>
Chris Lattner917cc712009-03-02 02:37:32 +0000422</ul>
423
Chris Lattner917cc712009-03-02 02:37:32 +0000424</div>
Chris Lattner84977642007-09-21 03:54:09 +0000425
426<!--=========================================================================-->
427<div class="doc_subsection">
Chris Lattner61358ab2009-10-13 17:48:04 +0000428<a name="ARM">ARM Target Improvements</a>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000429</div>
430
431<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000432<p>New features of the ARM target include:
433</p>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000434
435<ul>
Bob Wilsone8472772010-09-13 17:39:35 +0000436</ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000437</div>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000438
Chris Lattner77d29b12008-06-05 08:02:49 +0000439
440<!--=========================================================================-->
441<div class="doc_subsection">
Chris Lattnerf6662f92008-10-13 17:57:36 +0000442<a name="changes">Major Changes and Removed Features</a>
443</div>
444
445<div class="doc_text">
446
Chris Lattnereeb4da02008-10-13 22:06:31 +0000447<p>If you're already an LLVM user or developer with out-of-tree changes based
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000448on LLVM 2.8, this section lists some "gotchas" that you may run into upgrading
Chris Lattnereeb4da02008-10-13 22:06:31 +0000449from the previous release.</p>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000450
451<ul>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000452</ul>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000453
Chris Lattnerbb117712010-10-04 01:29:06 +0000454
455
Chris Lattnereeb4da02008-10-13 22:06:31 +0000456<p>In addition, many APIs have changed in this release. Some of the major LLVM
457API changes are:</p>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000458<ul>
Devang Patelb34dd132008-10-14 20:03:43 +0000459</ul>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000460
Chris Lattnerf6662f92008-10-13 17:57:36 +0000461</div>
462
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000463<!--=========================================================================-->
464<div class="doc_subsection">
465<a name="devtree_changes">Development Infrastructure Changes</a>
466</div>
467
468<div class="doc_text">
469
470<p>This section lists changes to the LLVM development infrastructure. This
471mostly impacts users who actively work on LLVM or follow development on
472mainline, but may also impact users who leverage the LLVM build infrastructure
473or are interested in LLVM qualification.</p>
474
475<ul>
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000476</ul>
477</div>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000478
Chris Lattner79c3fe12003-10-02 04:57:28 +0000479<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000480<div class="doc_section">
481 <a name="knownproblems">Known Problems</a>
482</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000483<!-- *********************************************************************** -->
484
Misha Brukman500bc302003-11-22 00:38:41 +0000485<div class="doc_text">
486
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000487<p>This section contains significant known problems with the LLVM system,
Chris Lattnere18b32e2008-11-10 05:40:34 +0000488listed by component. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000489href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000490there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000491
Misha Brukman500bc302003-11-22 00:38:41 +0000492</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000493
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000494<!-- ======================================================================= -->
495<div class="doc_subsection">
496 <a name="experimental">Experimental features included with this release</a>
497</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000498
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000499<div class="doc_text">
500
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000501<p>The following components of this LLVM release are either untested, known to
502be broken or unreliable, or are in early development. These components should
503not be relied on, and bugs should not be filed against them, but they may be
504useful to some people. In particular, if you would like to work on one of these
Chris Lattner2b659ef2008-02-12 06:29:45 +0000505components, please contact us on the <a
506href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000507
508<ul>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000509<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, PTX, SystemZ
Chris Lattnerbb117712010-10-04 01:29:06 +0000510 and XCore backends are experimental.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000511<li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000512 other than darwin-i386 and darwin-x86_64. FIXME: Not true on ELF anymore?</li>
513
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000514</ul>
515
516</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000517
Misha Brukman500bc302003-11-22 00:38:41 +0000518<!-- ======================================================================= -->
519<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000520 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000521</div>
522
523<div class="doc_text">
524
525<ul>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000526 <li>The X86 backend does not yet support
527 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
528 floating point stack</a>. It supports the 'f' and 't' constraints, but not
529 'u'.</li>
Duncan Sands47eff2b2008-06-08 19:38:43 +0000530 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswell524a5dd2009-03-02 15:28:15 +0000531 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
Chris Lattner914ce462010-04-22 06:28:20 +0000532 runtime currently due to lack of support for the 'u' inline assembly
533 constraint and for X87 floating point inline assembly.</li>
Dan Gohman8207ba92008-06-08 23:05:11 +0000534 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner914ce462010-04-22 06:28:20 +0000535 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman8207ba92008-06-08 23:05:11 +0000536 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000537</ul>
538
539</div>
540
541<!-- ======================================================================= -->
542<div class="doc_subsection">
543 <a name="ppc-be">Known problems with the PowerPC back-end</a>
544</div>
545
546<div class="doc_text">
547
548<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000549<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000550compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000551</ul>
552
553</div>
554
555<!-- ======================================================================= -->
556<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000557 <a name="arm-be">Known problems with the ARM back-end</a>
558</div>
559
560<div class="doc_text">
561
562<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000563<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000564processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000565results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswell524a5dd2009-03-02 15:28:15 +0000566<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000567</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000568</ul>
569
570</div>
571
572<!-- ======================================================================= -->
573<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000574 <a name="sparc-be">Known problems with the SPARC back-end</a>
575</div>
576
577<div class="doc_text">
578
579<ul>
John Criswell524a5dd2009-03-02 15:28:15 +0000580<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Chris Lattner26299222006-11-18 07:51:14 +0000581 support the 64-bit SPARC ABI (-m64).</li>
582</ul>
583
584</div>
585
586<!-- ======================================================================= -->
587<div class="doc_subsection">
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000588 <a name="mips-be">Known problems with the MIPS back-end</a>
589</div>
590
591<div class="doc_text">
592
593<ul>
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000594<li>64-bit MIPS targets are not supported yet.</li>
595</ul>
596
597</div>
598
599<!-- ======================================================================= -->
600<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000601 <a name="alpha-be">Known problems with the Alpha back-end</a>
602</div>
603
604<div class="doc_text">
605
606<ul>
607
608<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
609appropriate nops inserted to ensure restartability.</li>
610
John Criswellc0c186d2005-11-08 21:11:33 +0000611</ul>
612</div>
613
Chris Lattner26299222006-11-18 07:51:14 +0000614<!-- ======================================================================= -->
615<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000616 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000617</div>
618
619<div class="doc_text">
620
Chris Lattner3016ee92010-09-29 05:34:42 +0000621<p>The C backend has numerous problems and is not being actively maintained.
622Depending on it for anything serious is not advised.</p>
623
Chris Lattner26299222006-11-18 07:51:14 +0000624<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000625<li><a href="http://llvm.org/PR802">The C backend has only basic support for
626 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000627<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
628 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif4906abe2009-03-02 12:02:51 +0000629 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000630<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands50723a92009-02-25 11:51:54 +0000631<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000632</ul>
633
634</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000635
Misha Brukman500bc302003-11-22 00:38:41 +0000636
637<!-- ======================================================================= -->
638<div class="doc_subsection">
Chris Lattner3016ee92010-09-29 05:34:42 +0000639 <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000640</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000641
Misha Brukman500bc302003-11-22 00:38:41 +0000642<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000643
Chris Lattner3016ee92010-09-29 05:34:42 +0000644<p>llvm-gcc is generally very stable for the C family of languages. The only
645 major language feature of GCC not supported by llvm-gcc is the
646 <tt>__builtin_apply</tt> family of builtins. However, some extensions
647 are only supported on some targets. For example, trampolines are only
648 supported on some targets (these are used when you take the address of a
649 nested function).</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000650
Chris Lattner3016ee92010-09-29 05:34:42 +0000651<p>Fortran support generally works, but there are still several unresolved bugs
652 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
653 tools/gfortran component for details. Note that llvm-gcc is missing major
654 Fortran performance work in the frontend and library that went into GCC after
655 4.2. If you are interested in Fortran, we recommend that you consider using
656 <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000657
Duncan Sands3af96332010-10-04 10:06:56 +0000658<p>The llvm-gcc 4.2 Ada compiler has basic functionality, but is no longer being
659actively maintained. If you are interested in Ada, we recommend that you
660consider using <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000661</div>
662
Chris Lattner79c3fe12003-10-02 04:57:28 +0000663<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000664<div class="doc_section">
665 <a name="additionalinfo">Additional Information</a>
666</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000667<!-- *********************************************************************** -->
668
Misha Brukman500bc302003-11-22 00:38:41 +0000669<div class="doc_text">
670
Chris Lattner416db102005-05-16 17:13:10 +0000671<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000672href="http://llvm.org">LLVM web page</a>, in particular in the <a
673href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000674contains versions of the API documentation which is up-to-date with the
675Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000676You can access versions of these documents specific to this release by going
677into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000678
Misha Brukman500bc302003-11-22 00:38:41 +0000679<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerc463b272005-10-29 07:07:09 +0000680us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000681lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000682
Misha Brukman500bc302003-11-22 00:38:41 +0000683</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000684
685<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000686
Misha Brukman500bc302003-11-22 00:38:41 +0000687<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000688<address>
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Misha Brukman2061e892003-11-22 01:23:39 +0000693
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000694 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000695 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000696</address>
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699</html>