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Jeffrey Yasskinbec48772010-01-28 01:14:43 +00007 <title>LLVM 2.7 Release Notes</title>
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9<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +000010
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000011<div class="doc_title">LLVM 2.7 Release Notes</div>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +000012
Chris Lattner0e464a92010-03-17 04:02:39 +000013<img align=right src="http://llvm.org/img/DragonSmall.png"
14 width="136" height="136">
15
Chris Lattner79c3fe12003-10-02 04:57:28 +000016<ol>
Misha Brukman500bc302003-11-22 00:38:41 +000017 <li><a href="#intro">Introduction</a></li>
Chris Lattner96a445e2008-10-13 18:01:01 +000018 <li><a href="#subproj">Sub-project Status Update</a></li>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000019 <li><a href="#externalproj">External Projects Using LLVM 2.7</a></li>
20 <li><a href="#whatsnew">What's New in LLVM 2.7?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +000021 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +000022 <li><a href="#portability">Portability and Supported Platforms</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
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000031<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.7
32release.<br>
33You may prefer the
34<a href="http://llvm.org/releases/2.6/docs/ReleaseNotes.html">LLVM 2.6
35Release Notes</a>.</h1>
36
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
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000046Infrastructure, release 2.7. 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
Chris Lattnerc66bfef2010-03-17 04:41:49 +000062
Chris Lattnerdc910082010-03-17 06:41:58 +000063<p>FIXME: llvm.org moved to new server, mention new logo, Ted and Doug new code
64 owners.</p>
Chris Lattnerc66bfef2010-03-17 04:41:49 +000065
Misha Brukman500bc302003-11-22 00:38:41 +000066</div>
Chris Lattner61358ab2009-10-13 17:48:04 +000067
Chris Lattner79c3fe12003-10-02 04:57:28 +000068
Chris Lattner61358ab2009-10-13 17:48:04 +000069<!--
70Almost dead code.
71 include/llvm/Analysis/LiveValues.h => Dan
72 lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8.
73 llvm/Analysis/PointerTracking.h => Edwin wants this, consider for 2.8.
Chris Lattner76ef2982010-01-09 22:30:40 +000074 ABCD, SCCVN, GEPSplitterPass
Chris Lattner048fe3c2010-01-16 21:25:13 +000075 MSIL backend?
Chris Lattnerdc910082010-03-17 06:41:58 +000076 lib/Transforms/Utils/SSI.cpp -> ABCD depends on it.
Chris Lattner61358ab2009-10-13 17:48:04 +000077-->
78
79
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000080<!-- Features that need text if they're finished for 2.7:
Chris Lattner61358ab2009-10-13 17:48:04 +000081 gcc plugin.
82 strong phi elim
83 variable debug info for optimized code
Chris Lattnerab68e9e2009-02-26 22:33:38 +000084 postalloc scheduler: anti dependence breaking, hazard recognizer?
Chris Lattner61358ab2009-10-13 17:48:04 +000085 metadata
86 loop dependence analysis
87 ELF Writer? How stable?
88 <li>PostRA scheduler improvements, ARM adoption (David Goodwin).</li>
Chris Lattneracce85d2008-02-10 07:46:44 +000089 -->
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +000090
Chris Lattner547a3912008-10-12 19:47:48 +000091 <!-- for announcement email:
Chris Lattner61358ab2009-10-13 17:48:04 +000092 Logo web page.
93 llvm devmtg
94 compiler_rt
95 KLEE web page at klee.llvm.org
96 Many new papers added to /pubs/
Chris Lattnerdc910082010-03-17 06:41:58 +000097 Mention gcc plugin.
Chris Lattner74c80df2009-02-25 06:34:50 +000098 -->
Chris Lattneracce85d2008-02-10 07:46:44 +000099
Chris Lattner96a445e2008-10-13 18:01:01 +0000100<!-- *********************************************************************** -->
101<div class="doc_section">
102 <a name="subproj">Sub-project Status Update</a>
Chris Lattnerea34f642008-06-08 21:34:41 +0000103</div>
Chris Lattner96a445e2008-10-13 18:01:01 +0000104<!-- *********************************************************************** -->
Chris Lattnerea34f642008-06-08 21:34:41 +0000105
106<div class="doc_text">
Chris Lattner8348b472008-06-08 21:58:17 +0000107<p>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000108The LLVM 2.7 distribution currently consists of code from the core LLVM
Chris Lattner61358ab2009-10-13 17:48:04 +0000109repository (which roughly includes the LLVM optimizers, code generators
110and supporting tools), the Clang repository and the llvm-gcc repository. In
111addition to this code, the LLVM Project includes other sub-projects that are in
112development. Here we include updates on these subprojects.
Bill Wendling63d8c552009-03-02 04:28:57 +0000113</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000114
Chris Lattner8348b472008-06-08 21:58:17 +0000115</div>
116
Chris Lattner96a445e2008-10-13 18:01:01 +0000117
Chris Lattner8348b472008-06-08 21:58:17 +0000118<!--=========================================================================-->
Chris Lattner96a445e2008-10-13 18:01:01 +0000119<div class="doc_subsection">
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000120<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000121</div>
122
123<div class="doc_text">
124
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000125<p>The <a href="http://clang.llvm.org/">Clang project</a> is ...</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000126
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000127<p>In the LLVM 2.7 time-frame, the Clang team has made many improvements:</p>
Bill Wendling741748a2008-10-27 09:27:33 +0000128
Daniel Dunbar13739432008-10-14 23:25:09 +0000129<ul>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000130<li>...</li>
Chris Lattnerdc910082010-03-17 06:41:58 +0000131include a link to cxx_compatibility.html
Bill Wendling6bc15282009-03-02 04:28:18 +0000132</ul>
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000133</div>
134
135<!--=========================================================================-->
136<div class="doc_subsection">
137<a name="clangsa">Clang Static Analyzer</a>
138</div>
139
140<div class="doc_text">
141
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000142<p>Previously announced in the 2.4, 2.5, and 2.6 LLVM releases, the Clang project also
Ted Kremenek8b3894c2009-02-27 07:01:32 +0000143includes an early stage static source code analysis tool for <a
144href="http://clang.llvm.org/StaticAnalysis.html">automatically finding bugs</a>
Chris Lattner61358ab2009-10-13 17:48:04 +0000145in C and Objective-C programs. The tool performs checks to find
Ted Kremenek8b3894c2009-02-27 07:01:32 +0000146bugs that occur on a specific path within a program.</p>
Chris Lattnercc042612008-10-14 00:52:49 +0000147
Chris Lattner0e464a92010-03-17 04:02:39 +0000148<p>In the LLVM 2.7 time-frame, the analyzer core has sprouted legs and...</p>
Chris Lattner8348b472008-06-08 21:58:17 +0000149
150</div>
151
Chris Lattner96a445e2008-10-13 18:01:01 +0000152<!--=========================================================================-->
153<div class="doc_subsection">
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000154<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattner96a445e2008-10-13 18:01:01 +0000155</div>
156
157<div class="doc_text">
158<p>
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000159The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
Chris Lattner61358ab2009-10-13 17:48:04 +0000160a JVM and a CLI Virtual Machine (Microsoft .NET is an
161implementation of the CLI) using LLVM for static and just-in-time
162compilation.</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000163
Chris Lattner61358ab2009-10-13 17:48:04 +0000164<p>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000165VMKit version ?? builds with LLVM 2.7 and you can find it on its
Chris Lattner61358ab2009-10-13 17:48:04 +0000166<a href="http://vmkit.llvm.org/releases/">web page</a>. The release includes
Nicolas Geoffray56d313d2008-10-15 20:25:04 +0000167bug fixes, cleanup and new features. The major changes are:</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000168
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000169<ul>
170
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000171<li>...</li>
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000172
173</ul>
Chris Lattner96a445e2008-10-13 18:01:01 +0000174</div>
175
Chris Lattner61358ab2009-10-13 17:48:04 +0000176
177<!--=========================================================================-->
178<div class="doc_subsection">
179<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
180</div>
181
182<div class="doc_text">
183<p>
184The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
185is a simple library that provides an implementation of the low-level
186target-specific hooks required by code generation and other runtime components.
187For example, when compiling for a 32-bit target, converting a double to a 64-bit
188unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
189function. The compiler-rt library provides highly optimized implementations of
190this and other low-level routines (some are 3x faster than the equivalent
191libgcc routines).</p>
192
193<p>
194All of the code in the compiler-rt project is available under the standard LLVM
195License, a "BSD-style" license.</p>
196
197</div>
198
199<!--=========================================================================-->
200<div class="doc_subsection">
201<a name="klee">KLEE: Symbolic Execution and Automatic Test Case Generator</a>
202</div>
203
204<div class="doc_text">
205<p>
206The new LLVM <a href="http://klee.llvm.org/">KLEE project</a> is a symbolic
207execution framework for programs in LLVM bitcode form. KLEE tries to
208symbolically evaluate "all" paths through the application and records state
209transitions that lead to fault states. This allows it to construct testcases
210that lead to faults and can even be used to verify algorithms. For more
211details, please see the <a
212href="http://llvm.org/pubs/2008-12-OSDI-KLEE.html">OSDI 2008 paper</a> about
213KLEE.</p>
214
215</div>
216
217<!--=========================================================================-->
218<div class="doc_subsection">
219<a name="dragonegg">DragonEgg: GCC-4.5 as an LLVM frontend</a>
220</div>
221
222<div class="doc_text">
223<p>
224The goal of <a href="http://dragonegg.llvm.org/">DragonEgg</a> is to make
225gcc-4.5 act like llvm-gcc without requiring any gcc modifications whatsoever.
Duncan Sands78a1dcc2009-10-15 08:17:44 +0000226<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a shared library (dragonegg.so)
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000227that is loaded by gcc at runtime. It ...
Chris Lattner61358ab2009-10-13 17:48:04 +0000228</p>
229
230</div>
231
232
233<!--=========================================================================-->
234<div class="doc_subsection">
235<a name="mc">llvm-mc: Machine Code Toolkit</a>
236</div>
237
238<div class="doc_text">
239<p>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000240The LLVM Machine Code (MC) Toolkit project is ...
Chris Lattner61358ab2009-10-13 17:48:04 +0000241</p>
242
243</div>
244
245
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000246<!-- *********************************************************************** -->
247<div class="doc_section">
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000248 <a name="externalproj">External Open Source Projects Using LLVM 2.7</a>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000249</div>
250<!-- *********************************************************************** -->
251
Chris Lattner61358ab2009-10-13 17:48:04 +0000252<div class="doc_text">
253
254<p>An exciting aspect of LLVM is that it is used as an enabling technology for
255 a lot of other language and tools projects. This section lists some of the
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000256 projects that have already been updated to work with LLVM 2.7.</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000257</div>
258
259
260<!--=========================================================================-->
261<div class="doc_subsection">
262<a name="Rubinius">Rubinius</a>
263</div>
264
265<div class="doc_text">
Chris Lattner0e464a92010-03-17 04:02:39 +0000266Need update.
267<!--
Chris Lattner61358ab2009-10-13 17:48:04 +0000268<p><a href="http://github.com/evanphx/rubinius">Rubinius</a> is an environment
269for running Ruby code which strives to write as much of the core class
270implementation in Ruby as possible. Combined with a bytecode interpreting VM, it
271uses LLVM to optimize and compile ruby code down to machine code. Techniques
272such as type feedback, method inlining, and uncommon traps are all used to
273remove dynamism from ruby execution and increase performance.</p>
274
275<p>Since LLVM 2.5, Rubinius has made several major leaps forward, implementing
276a counter based JIT, type feedback and speculative method inlining.
Chris Lattner0e464a92010-03-17 04:02:39 +0000277-->
Chris Lattner61358ab2009-10-13 17:48:04 +0000278</p>
279
280</div>
281
282<!--=========================================================================-->
283<div class="doc_subsection">
284<a name="macruby">MacRuby</a>
285</div>
286
287<div class="doc_text">
288
289<p>
Chris Lattner0e464a92010-03-17 04:02:39 +0000290Need update.
291<!--
Chris Lattner61358ab2009-10-13 17:48:04 +0000292<a href="http://macruby.org">MacRuby</a> is an implementation of Ruby on top of
293core Mac OS X technologies, such as the Objective-C common runtime and garbage
294collector and the CoreFoundation framework. It is principally developed by
295Apple and aims at enabling the creation of full-fledged Mac OS X applications.
296</p>
297
298<p>
299MacRuby uses LLVM for optimization passes, JIT and AOT compilation of Ruby
300expressions. It also uses zero-cost DWARF exceptions to implement Ruby exception
Chris Lattner0e464a92010-03-17 04:02:39 +0000301handling.--> </p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000302
303</div>
304
305
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000306<!--=========================================================================-->
307<div class="doc_subsection">
308<a name="pure">Pure</a>
309</div>
310
311<div class="doc_text">
312<p>
Chris Lattner917cc712009-03-02 02:37:32 +0000313<a href="http://pure-lang.googlecode.com/">Pure</a>
314is an algebraic/functional programming language based on term rewriting.
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000315Programs are collections of equations which are used to evaluate expressions in
316a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000317lexical closures, a hygienic macro system (also based on term rewriting),
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000318built-in list and matrix support (including list and matrix comprehensions) and
319an easy-to-use C interface. The interpreter uses LLVM as a backend to
320 JIT-compile Pure programs to fast native code.</p>
321
Chris Lattner477a1fd2010-03-17 17:25:49 +0000322<p>Pure versions 0.43 and later have been tested and are known to work with
323LLVM 2.7 (and continue to work with older LLVM releases >= 2.5).</p>
324
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000325</div>
326
327
328<!--=========================================================================-->
329<div class="doc_subsection">
330<a name="ldc">LLVM D Compiler</a>
331</div>
332
333<div class="doc_text">
334<p>
Chris Lattner0e464a92010-03-17 04:02:39 +0000335Need update.
336<!--
Chris Lattner917cc712009-03-02 02:37:32 +0000337<a href="http://www.dsource.org/projects/ldc">LDC</a> is an implementation of
338the D Programming Language using the LLVM optimizer and code generator.
Chris Lattner61358ab2009-10-13 17:48:04 +0000339The LDC project works great with the LLVM 2.6 release. General improvements in
John Criswell524a5dd2009-03-02 15:28:15 +0000340this
Chris Lattner917cc712009-03-02 02:37:32 +0000341cycle have included new inline asm constraint handling, better debug info
Chris Lattner61358ab2009-10-13 17:48:04 +0000342support, general bug fixes and better x86-64 support. This has allowed
343some major improvements in LDC, getting it much closer to being as
Chris Lattner0e464a92010-03-17 04:02:39 +0000344fully featured as the original DMD compiler from DigitalMars.-->
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000345</p>
346</div>
347
Chris Lattnerbc31caf2009-02-28 18:58:01 +0000348<!--=========================================================================-->
349<div class="doc_subsection">
350<a name="RoadsendPHP">Roadsend PHP</a>
351</div>
352
353<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000354<p>
355<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
Chris Lattnercade8222009-03-02 19:07:24 +0000356source implementation of the PHP programming
Chris Lattner61358ab2009-10-13 17:48:04 +0000357language that uses LLVM for its optimizer, JIT and static compiler. This is a
Chris Lattner0e464a92010-03-17 04:02:39 +0000358reimplementation of an earlier project that is now based on LLVM.
Chris Lattner477a1fd2010-03-17 17:25:49 +0000359</p>
Chris Lattnerbc31caf2009-02-28 18:58:01 +0000360</div>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000361
Chris Lattner61358ab2009-10-13 17:48:04 +0000362<!--=========================================================================-->
363<div class="doc_subsection">
364<a name="UnladenSwallow">Unladen Swallow</a>
365</div>
366
367<div class="doc_text">
368<p>
369<a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
370branch of <a href="http://python.org/">Python</a> intended to be fully
371compatible and significantly faster. It uses LLVM's optimization passes and JIT
Chris Lattnerb5f6feb2010-03-18 06:52:15 +0000372compiler.
Chris Lattner0e464a92010-03-17 04:02:39 +0000373</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000374</div>
375
376<!--=========================================================================-->
377<div class="doc_subsection">
378<a name="llvm-lua">llvm-lua</a>
379</div>
380
381<div class="doc_text">
382<p>
Chris Lattner0e464a92010-03-17 04:02:39 +0000383Need update.
384<!--
Chris Lattner61358ab2009-10-13 17:48:04 +0000385<a href="http://code.google.com/p/llvm-lua/">LLVM-Lua</a> uses LLVM to add JIT
386and static compiling support to the Lua VM. Lua bytecode is analyzed to
387remove type checks, then LLVM is used to compile the bytecode down to machine
Chris Lattner0e464a92010-03-17 04:02:39 +0000388code.-->
389</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000390</div>
391
392<!--=========================================================================-->
393<div class="doc_subsection">
394<a name="icedtea">IcedTea Java Virtual Machine Implementation</a>
395</div>
396
397<div class="doc_text">
398<p>
Chris Lattner0e464a92010-03-17 04:02:39 +0000399Need update.
400<!--
Chris Lattner61358ab2009-10-13 17:48:04 +0000401<a href="http://icedtea.classpath.org/wiki/Main_Page">IcedTea</a> provides a
402harness to build OpenJDK using only free software build tools and to provide
403replacements for the not-yet free parts of OpenJDK. One of the extensions that
404IcedTea provides is a new JIT compiler named <a
405href="http://icedtea.classpath.org/wiki/ZeroSharkFaq">Shark</a> which uses LLVM
406to provide native code generation without introducing processor-dependent
Chris Lattner0e464a92010-03-17 04:02:39 +0000407code.-->
Chris Lattner61358ab2009-10-13 17:48:04 +0000408</p>
409</div>
410
411
Chris Lattner8348b472008-06-08 21:58:17 +0000412
413<!-- *********************************************************************** -->
414<div class="doc_section">
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000415 <a name="whatsnew">What's New in LLVM 2.7?</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000416</div>
417<!-- *********************************************************************** -->
418
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000419<div class="doc_text">
420
Chris Lattner61358ab2009-10-13 17:48:04 +0000421<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattnerf6662f92008-10-13 17:57:36 +0000422minor improvements. Some of the major improvements and new features are listed
423in this section.
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000424</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000425
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000426</div>
427
Chris Lattner8348b472008-06-08 21:58:17 +0000428<!--=========================================================================-->
Chris Lattnerea34f642008-06-08 21:34:41 +0000429<div class="doc_subsection">
Chris Lattner252b83d2008-02-06 18:00:06 +0000430<a name="majorfeatures">Major New Features</a>
431</div>
432
433<div class="doc_text">
434
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000435<p>LLVM 2.7 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000436
437<ul>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000438<li>...</li>
Chris Lattner8170c102008-02-10 08:18:42 +0000439</ul>
440
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000441Extensible metadata solid.
442
443Debug info improvements: using metadata instead of llvm.dbg global variables.
444This brings several enhancements including improved compile times.
445
446New instruction selector.
447GHC Haskell ABI/ calling conv support.
448Pre-Alpha support for unions in IR.
449New InlineHint and StackAlignment function attributes
450Code generator MC'ized except for debug info and EH.
451New SCEV AA pass: -scev-aa
452Inliner reuses arrays allocas when inlining multiple callers to reduce stack usage.
453MC encoding and disassembler apis.
454Optimal Edge Profiling?
455Instcombine is now a library, has its own IRBuilder to simplify itself.
456New llvm/Support/Regex.h API. FileCheck now does regex's
Chris Lattnerdc910082010-03-17 06:41:58 +0000457Many subtle pointer invalidation bugs in Callgraph have been fixed and it now uses asserting value handles.
458MC Disassembler (with blog post), MCInstPrinter. Many X86 backend and AsmPrinter simplifications
459Various tools like llc and opt now read either .ll or .bc files as input.
460Malloc and free instructions got removed.
461compiler-rt support for ARM.
462completely llvm-gcc NEON support.
463Can transcode from GAS to intel syntax with "llvm-mc foo.s -output-asm-variant=1"
464JIT debug information with GDB 7.0
Chris Lattnerf04bdc52010-03-17 18:15:52 +0000465New CodeGen Level CSE
Chris Lattnerdc910082010-03-17 06:41:58 +0000466CMake can now run tests, what other improvements?
Chris Lattnerf04bdc52010-03-17 18:15:52 +0000467ARM/Thumb using reg scavenging for stack object address materialization (PEI).
Chris Lattnerdc910082010-03-17 06:41:58 +0000468New SSAUpdater and MachineSSAUpdater classes for unstructured ssa updating,
469 changed jump threading, GVN, etc to use it which simplified them and speed
470 them up.
Chris Lattner15a06112010-03-17 06:42:25 +0000471Combiner-AA improvements, why not on by default?
Chris Lattnerf04bdc52010-03-17 18:15:52 +0000472Pre-regalloc tail duplication
473x86 sibcall optimization
474New LSR with full strength reduction mode
475The most awesome sext / zext optimization pass. ?
476
477
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000478
Chris Lattnerdc910082010-03-17 06:41:58 +0000479CondProp pass removed (functionality merged into jump threading).
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000480AndersAA got removed (from 2.7 or mainline?)
Chris Lattnerdc910082010-03-17 06:41:58 +0000481PredSimplify, LoopVR, GVNPRE got removed.
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000482LLVM command line tools now overwrite their output, before they would only do this with -f.
483DOUT removed, use DEBUG(errs() instead.
484Much stuff converted to use raw_ostream instead of std::ostream.
485TargetAsmInfo renamed to MCAsmInfo
486llvm/ADT/iterator.h gone.
487
Chris Lattnerdc910082010-03-17 06:41:58 +0000488
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000489</div>
490
Chris Lattner84977642007-09-21 03:54:09 +0000491<!--=========================================================================-->
492<div class="doc_subsection">
Chris Lattner917cc712009-03-02 02:37:32 +0000493<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000494</div>
495
496<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000497<p>LLVM IR has several new features for better support of new targets and that
498expose new optimization opportunities:</p>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000499
Chris Lattner791f77b2008-06-05 06:25:56 +0000500<ul>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000501<li>...</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000502</ul>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000503
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000504</div>
505
506<!--=========================================================================-->
507<div class="doc_subsection">
Chris Lattneracce85d2008-02-10 07:46:44 +0000508<a name="optimizer">Optimizer Improvements</a>
509</div>
510
511<div class="doc_text">
512
Chris Lattner61358ab2009-10-13 17:48:04 +0000513<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattnerf3013872008-10-13 21:50:36 +0000514release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000515
516<ul>
517
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000518<li>...</li>
Chris Lattner917cc712009-03-02 02:37:32 +0000519
Chris Lattner61358ab2009-10-13 17:48:04 +0000520</ul>
Chris Lattner917cc712009-03-02 02:37:32 +0000521
Chris Lattnerf2201912010-03-01 19:29:17 +0000522<p>Also, -anders-aa was removed</p>
523
Chris Lattner61358ab2009-10-13 17:48:04 +0000524</div>
Chris Lattner917cc712009-03-02 02:37:32 +0000525
Chris Lattner917cc712009-03-02 02:37:32 +0000526
Chris Lattner61358ab2009-10-13 17:48:04 +0000527<!--=========================================================================-->
528<div class="doc_subsection">
529<a name="executionengine">Interpreter and JIT Improvements</a>
530</div>
Chris Lattnerf3013872008-10-13 21:50:36 +0000531
Chris Lattner61358ab2009-10-13 17:48:04 +0000532<div class="doc_text">
533
534<ul>
Jeffrey Yasskin01eba392010-01-29 19:10:38 +0000535<li>The JIT now <a
536href="http://llvm.org/viewvc/llvm-project?view=rev&revision=85295">defaults
537to compiling eagerly</a> to avoid a race condition in the lazy JIT.
538Clients that still want the lazy JIT can switch it on by calling
539<tt>ExecutionEngine::DisableLazyCompilation(false)</tt>.</li>
Jeffrey Yasskin40966a72010-02-11 01:07:39 +0000540<li>It is now possible to create more than one JIT instance in the same process.
541These JITs can generate machine code in parallel,
542although <a href="http://llvm.org/docs/ProgrammersManual.html#jitthreading">you
543still have to obey the other threading restrictions</a>.</li>
Chris Lattner0b832202008-06-08 02:45:07 +0000544</ul>
545
546</div>
547
548<!--=========================================================================-->
549<div class="doc_subsection">
Chris Lattner511433e2009-03-02 03:24:11 +0000550<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner0b832202008-06-08 02:45:07 +0000551</div>
552
553<div class="doc_text">
554
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000555<p>We have put a significant amount of work into the code generator
556infrastructure, which allows us to implement more aggressive algorithms and make
557it run faster:</p>
Chris Lattner0b832202008-06-08 02:45:07 +0000558
559<ul>
Chris Lattner511433e2009-03-02 03:24:11 +0000560
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000561<li>...</li>
Chris Lattner84977642007-09-21 03:54:09 +0000562</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000563</div>
564
Chris Lattner917cc712009-03-02 02:37:32 +0000565<!--=========================================================================-->
566<div class="doc_subsection">
567<a name="x86">X86-32 and X86-64 Target Improvements</a>
568</div>
569
570<div class="doc_text">
571<p>New features of the X86 target include:
572</p>
573
574<ul>
Chris Lattner511433e2009-03-02 03:24:11 +0000575
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000576<li>...</li>
Chris Lattner511433e2009-03-02 03:24:11 +0000577
Chris Lattner917cc712009-03-02 02:37:32 +0000578</ul>
579
Chris Lattner917cc712009-03-02 02:37:32 +0000580</div>
Chris Lattner84977642007-09-21 03:54:09 +0000581
582<!--=========================================================================-->
583<div class="doc_subsection">
Chris Lattner11398992009-02-26 07:32:11 +0000584<a name="pic16">PIC16 Target Improvements</a>
585</div>
586
587<div class="doc_text">
588<p>New features of the PIC16 target include:
589</p>
590
591<ul>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000592<li>...</li>
Chris Lattner11398992009-02-26 07:32:11 +0000593</ul>
594
595<p>Things not yet supported:</p>
596
597<ul>
Chris Lattner11398992009-02-26 07:32:11 +0000598<li>Variable arguments.</li>
Chris Lattner511433e2009-03-02 03:24:11 +0000599<li>Interrupts/programs.</li>
Chris Lattner11398992009-02-26 07:32:11 +0000600</ul>
601
602</div>
603
Chris Lattner11398992009-02-26 07:32:11 +0000604<!--=========================================================================-->
605<div class="doc_subsection">
Chris Lattner61358ab2009-10-13 17:48:04 +0000606<a name="ARM">ARM Target Improvements</a>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000607</div>
608
609<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000610<p>New features of the ARM target include:
611</p>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000612
613<ul>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000614
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000615<li>...</li>
Chris Lattner61358ab2009-10-13 17:48:04 +0000616</ul>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000617
Chris Lattnerc441fb82009-03-01 02:30:21 +0000618
Chris Lattner61358ab2009-10-13 17:48:04 +0000619</div>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000620
Chris Lattner61358ab2009-10-13 17:48:04 +0000621<!--=========================================================================-->
622<div class="doc_subsection">
623<a name="OtherTarget">Other Target Specific Improvements</a>
624</div>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000625
Chris Lattner61358ab2009-10-13 17:48:04 +0000626<div class="doc_text">
627<p>New features of other targets include:
628</p>
629
630<ul>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000631<li>...</li>
Chris Lattner61358ab2009-10-13 17:48:04 +0000632</ul>
633
634</div>
635
636<!--=========================================================================-->
637<div class="doc_subsection">
638<a name="newapis">New Useful APIs</a>
639</div>
640
641<div class="doc_text">
642
643<p>This release includes a number of new APIs that are used internally, which
644 may also be useful for external clients.
645</p>
646
647<ul>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000648<li>...</li>
Chris Lattner61358ab2009-10-13 17:48:04 +0000649</ul>
650
651
652</div>
653
654<!--=========================================================================-->
655<div class="doc_subsection">
656<a name="otherimprovements">Other Improvements and New Features</a>
657</div>
658
659<div class="doc_text">
660<p>Other miscellaneous features include:</p>
661
662<ul>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000663<li>...</li>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000664</ul>
665
666</div>
667
Chris Lattner77d29b12008-06-05 08:02:49 +0000668
669<!--=========================================================================-->
670<div class="doc_subsection">
Chris Lattnerf6662f92008-10-13 17:57:36 +0000671<a name="changes">Major Changes and Removed Features</a>
672</div>
673
674<div class="doc_text">
675
Chris Lattnereeb4da02008-10-13 22:06:31 +0000676<p>If you're already an LLVM user or developer with out-of-tree changes based
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000677on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading
Chris Lattnereeb4da02008-10-13 22:06:31 +0000678from the previous release.</p>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000679
680<ul>
Jeffrey Yasskinbc83d062010-02-09 23:03:44 +0000681<li>The LLVM interpreter now defaults to <em>not</em> using <tt>libffi</tt> even
682if you have it installed. This makes it more likely that an LLVM built on one
683system will work when copied to a similar system. To use <tt>libffi</tt>,
684configure with <tt>--enable-libffi</tt>.
685</li>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000686</ul>
687
688
689<p>In addition, many APIs have changed in this release. Some of the major LLVM
690API changes are:</p>
691
692<ul>
Jeffrey Yasskin4fcd6072010-01-28 01:41:20 +0000693<li><tt>ModuleProvider</tt> has been <a
694href="http://llvm.org/viewvc/llvm-project?view=rev&revision=94686">removed</a>
695and its methods moved to <tt>Module</tt> and <tt>GlobalValue</tt>.
696Most clients can remove uses of <tt>ExistingModuleProvider</tt>,
697replace <tt>getBitcodeModuleProvider</tt> with
698<tt>getLazyBitcodeModule</tt>, and pass their <tt>Module</tt> to
699functions that used to accept <tt>ModuleProvider</tt>. Clients who
700wrote their own <tt>ModuleProvider</tt>s will need to derive from
701<tt>GVMaterializer</tt> instead and use
702<tt>Module::setMaterializer</tt> to attach it to a
703<tt>Module</tt>.</li>
704
705<li><tt>GhostLinkage</tt> has given up the ghost.
706<tt>GlobalValue</tt>s that have not yet been read from their backing
707storage have the same linkage they will have after being read in.
708Clients must replace calls to
709<tt>GlobalValue::hasNotBeenReadFromBitcode</tt> with
710<tt>GlobalValue::isMaterializable</tt>.</li>
Daniel Dunbar4acdede2010-02-10 04:09:52 +0000711
712<li>FIXME: Debug info has been totally redone. Add pointers to new APIs. Substantial caveats about compatibility of .ll and .bc files.</li>
713
Daniel Dunbarca1c8162010-02-14 01:47:19 +0000714<li>The <tt>llvm/Support/DataTypes.h</tt> header has moved
715to <tt>llvm/System/DataTypes.h</tt>.</li>
716
Duncan Sands411432d2010-02-17 17:20:17 +0000717<li>The <tt>isInteger</tt>, <tt>isIntOrIntVector</tt>, <tt>isFloatingPoint</tt>,
718<tt>isFPOrFPVector</tt> and <tt>isFPOrFPVector</tt> methods have been renamed
719<tt>isIntegerTy</tt>, <tt>isIntOrIntVectorTy</tt>, <tt>isFloatingPointTy</tt>,
720<tt>isFPOrFPVectorTy</tt> and <tt>isFPOrFPVectorTy</tt> respectively.</li>
Devang Patelb34dd132008-10-14 20:03:43 +0000721</ul>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000722
Chris Lattnerf6662f92008-10-13 17:57:36 +0000723</div>
724
725
726
Chris Lattner19092612003-10-02 16:38:05 +0000727<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000728<div class="doc_section">
729 <a name="portability">Portability and Supported Platforms</a>
730</div>
Chris Lattner19092612003-10-02 16:38:05 +0000731<!-- *********************************************************************** -->
732
Misha Brukman500bc302003-11-22 00:38:41 +0000733<div class="doc_text">
734
John Criswell0b5b5e92004-12-08 20:35:47 +0000735<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000736
737<ul>
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000738<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattner61358ab2009-10-13 17:48:04 +0000739 Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like
740 systems).</li>
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000741<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit
Chris Lattner61358ab2009-10-13 17:48:04 +0000742 and 64-bit modes.</li>
Chris Lattner252b83d2008-02-06 18:00:06 +0000743<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000744<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
745 support is available for native builds with Visual C++).</li>
Chris Lattner7e23d6e2009-10-16 16:30:58 +0000746<li>Sun x86 and AMD64 machines running Solaris 10, OpenSolaris 0906.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000747<li>Alpha-based machines running Debian GNU/Linux.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000748</ul>
749
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000750<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000751to the machine and operating system on which it is built. However, minor
752porting may be required to get LLVM to work on new platforms. We welcome your
753portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000754
Misha Brukman500bc302003-11-22 00:38:41 +0000755</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000756
757<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000758<div class="doc_section">
759 <a name="knownproblems">Known Problems</a>
760</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000761<!-- *********************************************************************** -->
762
Misha Brukman500bc302003-11-22 00:38:41 +0000763<div class="doc_text">
764
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000765<p>This section contains significant known problems with the LLVM system,
Chris Lattnere18b32e2008-11-10 05:40:34 +0000766listed by component. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000767href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000768there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000769
Chris Lattner477a1fd2010-03-17 17:25:49 +0000770<ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000771<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
772using the stock GCC 3.x.x series 'out the box',
Chris Lattner554ee4a2009-11-03 21:50:09 +0000773See: <a href="GettingStarted.html#brokengcc">Broken versions of GCC and other tools</a>.
Chris Lattner61358ab2009-10-13 17:48:04 +0000774However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
775for x86/x86-64 has been made available from the third party AuroraUX Project
776that has been meticulously tested for bootstrapping LLVM &amp; Clang.</li>
777</ul>
778
Misha Brukman500bc302003-11-22 00:38:41 +0000779</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000780
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000781<!-- ======================================================================= -->
782<div class="doc_subsection">
783 <a name="experimental">Experimental features included with this release</a>
784</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000785
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000786<div class="doc_text">
787
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000788<p>The following components of this LLVM release are either untested, known to
789be broken or unreliable, or are in early development. These components should
790not be relied on, and bugs should not be filed against them, but they may be
791useful to some people. In particular, if you would like to work on one of these
Chris Lattner2b659ef2008-02-12 06:29:45 +0000792components, please contact us on the <a
793href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000794
795<ul>
Wesley Peck7c4a1212010-03-18 14:31:30 +0000796<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
797 backends are experimental.</li>
Bill Wendling99dac472009-03-02 07:54:14 +0000798<li>The <tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000799 supported value for this option. The MachO writer is experimental, and
800 works much better in mainline SVN.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000801</ul>
802
803</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000804
Misha Brukman500bc302003-11-22 00:38:41 +0000805<!-- ======================================================================= -->
806<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000807 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000808</div>
809
810<div class="doc_text">
811
812<ul>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000813 <li>The X86 backend does not yet support
814 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
815 floating point stack</a>. It supports the 'f' and 't' constraints, but not
816 'u'.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000817 <li>The X86 backend generates inefficient floating point code when configured
818 to generate code for systems that don't have SSE2.</li>
Duncan Sands47eff2b2008-06-08 19:38:43 +0000819 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswell524a5dd2009-03-02 15:28:15 +0000820 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
821 runtime currently due
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000822 to <a href="http://llvm.org/PR2255">several</a>
John Criswell524a5dd2009-03-02 15:28:15 +0000823 <a href="http://llvm.org/PR2257">bugs</a> and due to lack of support for
824 the
825 'u' inline assembly constraint and for X87 floating point inline assembly.</li>
Dan Gohman8207ba92008-06-08 23:05:11 +0000826 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner917cc712009-03-02 02:37:32 +0000827 <tt>va_arg</tt>. Currently, the llvm-gcc and front-ends support variadic
Dan Gohman8207ba92008-06-08 23:05:11 +0000828 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000829</ul>
830
831</div>
832
833<!-- ======================================================================= -->
834<div class="doc_subsection">
835 <a name="ppc-be">Known problems with the PowerPC back-end</a>
836</div>
837
838<div class="doc_text">
839
840<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000841<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000842compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000843</ul>
844
845</div>
846
847<!-- ======================================================================= -->
848<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000849 <a name="arm-be">Known problems with the ARM back-end</a>
850</div>
851
852<div class="doc_text">
853
854<ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000855<li>Support for the Advanced SIMD (Neon) instruction set is still incomplete
856and not well tested. Some features may not work at all, and the code quality
857may be poor in some cases.</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000858<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000859processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000860results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswell524a5dd2009-03-02 15:28:15 +0000861<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000862</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000863</ul>
864
865</div>
866
867<!-- ======================================================================= -->
868<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000869 <a name="sparc-be">Known problems with the SPARC back-end</a>
870</div>
871
872<div class="doc_text">
873
874<ul>
John Criswell524a5dd2009-03-02 15:28:15 +0000875<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Chris Lattner26299222006-11-18 07:51:14 +0000876 support the 64-bit SPARC ABI (-m64).</li>
877</ul>
878
879</div>
880
881<!-- ======================================================================= -->
882<div class="doc_subsection">
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000883 <a name="mips-be">Known problems with the MIPS back-end</a>
884</div>
885
886<div class="doc_text">
887
888<ul>
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000889<li>64-bit MIPS targets are not supported yet.</li>
890</ul>
891
892</div>
893
894<!-- ======================================================================= -->
895<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000896 <a name="alpha-be">Known problems with the Alpha back-end</a>
897</div>
898
899<div class="doc_text">
900
901<ul>
902
903<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
904appropriate nops inserted to ensure restartability.</li>
905
John Criswellc0c186d2005-11-08 21:11:33 +0000906</ul>
907</div>
908
Chris Lattner26299222006-11-18 07:51:14 +0000909<!-- ======================================================================= -->
910<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000911 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000912</div>
913
914<div class="doc_text">
915
916<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000917<li><a href="http://llvm.org/PR802">The C backend has only basic support for
918 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000919<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
920 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif4906abe2009-03-02 12:02:51 +0000921 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000922<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands50723a92009-02-25 11:51:54 +0000923<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000924</ul>
925
926</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000927
Misha Brukman500bc302003-11-22 00:38:41 +0000928
929<!-- ======================================================================= -->
930<div class="doc_subsection">
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000931 <a name="c-fe">Known problems with the llvm-gcc C and C++ front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000932</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000933
Misha Brukman500bc302003-11-22 00:38:41 +0000934<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000935
Chris Lattner5733b272008-06-05 06:35:40 +0000936<p>The only major language feature of GCC not supported by llvm-gcc is
937 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
938 are only supported on some targets. For example, trampolines are only
Duncan Sands27aff872008-06-08 20:18:35 +0000939 supported on some targets (these are used when you take the address of a
940 nested function).</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000941
Chris Lattner5733b272008-06-05 06:35:40 +0000942<p>If you run into GCC extensions which are not supported, please let us know.
943</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000944
Misha Brukman500bc302003-11-22 00:38:41 +0000945</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000946
Misha Brukman500bc302003-11-22 00:38:41 +0000947<!-- ======================================================================= -->
948<div class="doc_subsection">
Chris Lattner1eb4df62008-10-30 03:58:13 +0000949 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
950</div>
951
952<div class="doc_text">
Gabor Greifba10fe02008-11-04 21:50:59 +0000953<ul>
Chris Lattner1eb4df62008-10-30 03:58:13 +0000954<li>Fortran support generally works, but there are still several unresolved bugs
Chris Lattner61358ab2009-10-13 17:48:04 +0000955 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
956 tools/gfortran component for details.</li>
Gabor Greifba10fe02008-11-04 21:50:59 +0000957</ul>
Chris Lattner1eb4df62008-10-30 03:58:13 +0000958</div>
Misha Brukman500bc302003-11-22 00:38:41 +0000959
Chris Lattner2b659ef2008-02-12 06:29:45 +0000960<!-- ======================================================================= -->
961<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000962 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000963</div>
964
965<div class="doc_text">
John Criswell524a5dd2009-03-02 15:28:15 +0000966The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
967technology, and problems should be expected.
Chris Lattner2b659ef2008-02-12 06:29:45 +0000968<ul>
Duncan Sands27aff872008-06-08 20:18:35 +0000969<li>The Ada front-end currently only builds on X86-32. This is mainly due
John Criswell524a5dd2009-03-02 15:28:15 +0000970to lack of trampoline support (pointers to nested functions) on other platforms.
971However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000972which does support trampolines.</li>
973<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
Duncan Sands326a4982009-02-25 11:59:06 +0000974This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
975exception handling, which is used internally by the compiler.
Chris Lattner61358ab2009-10-13 17:48:04 +0000976Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
Duncan Sands978bcee2008-10-13 17:27:23 +0000977<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
978and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sands326a4982009-02-25 11:59:06 +0000979(c380004 also fails with gcc-4.2 mainline).
980If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
981causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sandsdd3e6722009-03-02 16:35:57 +0000982<li>Some GCC specific Ada tests continue to crash the compiler.</li>
Chris Lattner61358ab2009-10-13 17:48:04 +0000983<li>The <tt>-E</tt> binder option (exception backtraces)
Chris Lattner2b659ef2008-02-12 06:29:45 +0000984<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
Chris Lattner61358ab2009-10-13 17:48:04 +0000985crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000986<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
987or finish at a non-byte offset</a> in a record. Workaround: do not pack records
988or use representation clauses that result in a field of a non-discrete type
989starting or finishing in the middle of a byte.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000990<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
991'main' as generated by the Ada binder to be invalid</a>.
992Workaround: hand edit the file to use pointers for <tt>argv</tt> and
993<tt>envp</tt> rather than integers.</li>
994<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
995ignored</a>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000996</ul>
997</div>
998
Chris Lattner61358ab2009-10-13 17:48:04 +0000999<!-- ======================================================================= -->
1000<div class="doc_subsection">
1001 <a name="ocaml-bindings">Known problems with the O'Caml bindings</a>
1002</div>
1003
1004<div class="doc_text">
1005
1006<p>The <tt>Llvm.Linkage</tt> module is broken, and has incorrect values. Only
1007<tt>Llvm.Linkage.External</tt>, <tt>Llvm.Linkage.Available_externally</tt>, and
1008<tt>Llvm.Linkage.Link_once</tt> will be correct. If you need any of the other linkage
1009modes, you'll have to write an external C library in order to expose the
1010functionality. This has been fixed in the trunk.</p>
1011</div>
1012
Chris Lattner79c3fe12003-10-02 04:57:28 +00001013<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +00001014<div class="doc_section">
1015 <a name="additionalinfo">Additional Information</a>
1016</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +00001017<!-- *********************************************************************** -->
1018
Misha Brukman500bc302003-11-22 00:38:41 +00001019<div class="doc_text">
1020
Chris Lattner416db102005-05-16 17:13:10 +00001021<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +00001022href="http://llvm.org">LLVM web page</a>, in particular in the <a
1023href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +00001024contains versions of the API documentation which is up-to-date with the
1025Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +00001026You can access versions of these documents specific to this release by going
1027into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +00001028
Misha Brukman500bc302003-11-22 00:38:41 +00001029<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerc463b272005-10-29 07:07:09 +00001030us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +00001031lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +00001032
Misha Brukman500bc302003-11-22 00:38:41 +00001033</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +00001034
1035<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +00001036
Misha Brukman500bc302003-11-22 00:38:41 +00001037<hr>
Misha Brukman2061e892003-11-22 01:23:39 +00001038<address>
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Misha Brukman2061e892003-11-22 01:23:39 +00001043
Chris Lattnerb4b0ce72007-05-18 00:44:29 +00001044 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
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