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Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +00007 <title>LLVM 2.7 Release Notes</title>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00008</head>
9<body>
10
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +000011<div class="doc_title">LLVM 2.7 Release Notes</div>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +000012
Chris Lattnere5236102010-03-17 04:02:39 +000013<img align=right src="http://llvm.org/img/DragonSmall.png"
14 width="136" height="136">
15
Dan Gohmanf17a25c2007-07-18 16:29:46 +000016<ol>
17 <li><a href="#intro">Introduction</a></li>
Chris Lattner78a130b2008-10-13 18:01:01 +000018 <li><a href="#subproj">Sub-project Status Update</a></li>
Jeffrey Yasskin8ee1b0a2010-01-28 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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000021 <li><a href="GettingStarted.html">Installation Instructions</a></li>
22 <li><a href="#portability">Portability and Supported Platforms</a></li>
Dan Gohman0de549c2008-10-14 16:23:02 +000023 <li><a href="#knownproblems">Known Problems</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000024 <li><a href="#additionalinfo">Additional Information</a></li>
25</ol>
26
27<div class="doc_author">
Dan Gohman0de549c2008-10-14 16:23:02 +000028 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000029</div>
30
Jeffrey Yasskin8ee1b0a2010-01-28 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
Dan Gohmanf17a25c2007-07-18 16:29:46 +000037<!-- *********************************************************************** -->
38<div class="doc_section">
39 <a name="intro">Introduction</a>
40</div>
41<!-- *********************************************************************** -->
42
43<div class="doc_text">
44
Chris Lattner92eacf82008-10-13 17:57:36 +000045<p>This document contains the release notes for the LLVM Compiler
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +000046Infrastructure, release 2.7. Here we describe the status of LLVM, including
Chris Lattner92eacf82008-10-13 17:57:36 +000047major improvements from the previous release and significant known problems.
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +000048All LLVM releases may be downloaded from the <a
Chris Lattner92eacf82008-10-13 17:57:36 +000049href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000050
51<p>For more information about LLVM, including information about the latest
52release, please check out the <a href="http://llvm.org/">main LLVM
53web site</a>. If you have questions or comments, the <a
Chris Lattner58b1d0f2010-03-17 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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000056
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +000057<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattnerb0d6c502007-09-21 03:54:09 +000058main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greif7c65c4f2008-10-14 11:00:32 +000059current one. To see the release notes for a specific release, please see the
Chris Lattnerb0d6c502007-09-21 03:54:09 +000060<a href="http://llvm.org/releases/">releases page</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000061
Chris Lattner58b1d0f2010-03-17 04:41:49 +000062
Chris Lattner2b656342010-03-17 06:41:58 +000063<p>FIXME: llvm.org moved to new server, mention new logo, Ted and Doug new code
64 owners.</p>
Chris Lattner58b1d0f2010-03-17 04:41:49 +000065
Dan Gohmanf17a25c2007-07-18 16:29:46 +000066</div>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +000067
Dan Gohmanf17a25c2007-07-18 16:29:46 +000068
Chris Lattner0b6ea7a2009-10-13 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 Lattner35da3812010-01-09 22:30:40 +000074 ABCD, SCCVN, GEPSplitterPass
Chris Lattner2bd5e652010-01-16 21:25:13 +000075 MSIL backend?
Chris Lattner2b656342010-03-17 06:41:58 +000076 lib/Transforms/Utils/SSI.cpp -> ABCD depends on it.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +000077-->
78
79
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +000080<!-- Features that need text if they're finished for 2.7:
Chris Lattner0b6ea7a2009-10-13 17:48:04 +000081 gcc plugin.
82 strong phi elim
83 variable debug info for optimized code
Chris Lattnerb2cc5022009-02-26 22:33:38 +000084 postalloc scheduler: anti dependence breaking, hazard recognizer?
Chris Lattner0b6ea7a2009-10-13 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 Lattner8fda4952008-02-10 07:46:44 +000089 -->
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +000090
Chris Lattner4f076402008-10-12 19:47:48 +000091 <!-- for announcement email:
Chris Lattner0b6ea7a2009-10-13 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 Lattner2b656342010-03-17 06:41:58 +000097 Mention gcc plugin.
Chris Lattnera53f4972009-02-25 06:34:50 +000098 -->
Chris Lattner8fda4952008-02-10 07:46:44 +000099
Chris Lattner78a130b2008-10-13 18:01:01 +0000100<!-- *********************************************************************** -->
101<div class="doc_section">
102 <a name="subproj">Sub-project Status Update</a>
Chris Lattnerf65224f2008-06-08 21:34:41 +0000103</div>
Chris Lattner78a130b2008-10-13 18:01:01 +0000104<!-- *********************************************************************** -->
Chris Lattnerf65224f2008-06-08 21:34:41 +0000105
106<div class="doc_text">
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000107<p>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000108The LLVM 2.7 distribution currently consists of code from the core LLVM
Chris Lattner0b6ea7a2009-10-13 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 Wendlingdde41b82009-03-02 04:28:57 +0000113</p>
Chris Lattner78a130b2008-10-13 18:01:01 +0000114
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000115</div>
116
Chris Lattner78a130b2008-10-13 18:01:01 +0000117
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000118<!--=========================================================================-->
Chris Lattner78a130b2008-10-13 18:01:01 +0000119<div class="doc_subsection">
Chris Lattnera3c683b2008-10-13 18:11:54 +0000120<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000121</div>
122
123<div class="doc_text">
124
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000125<p>The <a href="http://clang.llvm.org/">Clang project</a> is ...</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000126
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000127<p>In the LLVM 2.7 time-frame, the Clang team has made many improvements:</p>
Bill Wendling385b0d32008-10-27 09:27:33 +0000128
Daniel Dunbarf3e35782008-10-14 23:25:09 +0000129<ul>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000130<li>...</li>
Chris Lattner2b656342010-03-17 06:41:58 +0000131include a link to cxx_compatibility.html
Bill Wendlinga8fb81d2009-03-02 04:28:18 +0000132</ul>
Chris Lattnera3c683b2008-10-13 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 Yasskin8ee1b0a2010-01-28 01:14:43 +0000142<p>Previously announced in the 2.4, 2.5, and 2.6 LLVM releases, the Clang project also
Ted Kremeneka0d77d72009-02-27 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 Lattner0b6ea7a2009-10-13 17:48:04 +0000145in C and Objective-C programs. The tool performs checks to find
Ted Kremeneka0d77d72009-02-27 07:01:32 +0000146bugs that occur on a specific path within a program.</p>
Chris Lattnerc2d84672008-10-14 00:52:49 +0000147
Chris Lattnere5236102010-03-17 04:02:39 +0000148<p>In the LLVM 2.7 time-frame, the analyzer core has sprouted legs and...</p>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000149
150</div>
151
Chris Lattner78a130b2008-10-13 18:01:01 +0000152<!--=========================================================================-->
153<div class="doc_subsection">
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000154<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattner78a130b2008-10-13 18:01:01 +0000155</div>
156
157<div class="doc_text">
158<p>
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000159The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
Chris Lattner0b6ea7a2009-10-13 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 Lattner78a130b2008-10-13 18:01:01 +0000163
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000164<p>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000165VMKit version ?? builds with LLVM 2.7 and you can find it on its
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000166<a href="http://vmkit.llvm.org/releases/">web page</a>. The release includes
Nicolas Geoffray20cfdd42008-10-15 20:25:04 +0000167bug fixes, cleanup and new features. The major changes are:</p>
Chris Lattner78a130b2008-10-13 18:01:01 +0000168
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000169<ul>
170
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000171<li>...</li>
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000172
173</ul>
Chris Lattner78a130b2008-10-13 18:01:01 +0000174</div>
175
Chris Lattner0b6ea7a2009-10-13 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 Sandsf6fb7142009-10-15 08:17:44 +0000226<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a shared library (dragonegg.so)
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000227that is loaded by gcc at runtime. It ...
Chris Lattner0b6ea7a2009-10-13 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 Yasskin8ee1b0a2010-01-28 01:14:43 +0000240The LLVM Machine Code (MC) Toolkit project is ...
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000241</p>
242
243</div>
244
245
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000246<!-- *********************************************************************** -->
247<div class="doc_section">
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000248 <a name="externalproj">External Open Source Projects Using LLVM 2.7</a>
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000249</div>
250<!-- *********************************************************************** -->
251
Chris Lattner0b6ea7a2009-10-13 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 Yasskin8ee1b0a2010-01-28 01:14:43 +0000256 projects that have already been updated to work with LLVM 2.7.</p>
Chris Lattner0b6ea7a2009-10-13 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 Lattnere5236102010-03-17 04:02:39 +0000266Need update.
267<!--
Chris Lattner0b6ea7a2009-10-13 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 Lattnere5236102010-03-17 04:02:39 +0000277-->
Chris Lattner0b6ea7a2009-10-13 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 Lattnere5236102010-03-17 04:02:39 +0000290Need update.
291<!--
Chris Lattner0b6ea7a2009-10-13 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 Lattnere5236102010-03-17 04:02:39 +0000301handling.--> </p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000302
303</div>
304
305
Chris Lattnerb2cc5022009-02-26 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 Lattnere5236102010-03-17 04:02:39 +0000313Need update.
314<!--
Chris Lattner47202c32009-03-02 02:37:32 +0000315<a href="http://pure-lang.googlecode.com/">Pure</a>
316is an algebraic/functional programming language based on term rewriting.
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000317Programs are collections of equations which are used to evaluate expressions in
318a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000319lexical closures, a hygienic macro system (also based on term rewriting),
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000320built-in list and matrix support (including list and matrix comprehensions) and
321an easy-to-use C interface. The interpreter uses LLVM as a backend to
322 JIT-compile Pure programs to fast native code.</p>
323
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000324<p>Pure versions ??? and later have been tested and are known to work with
325LLVM 2.7 (and continue to work with older LLVM releases >= 2.3 as well).
Chris Lattnere5236102010-03-17 04:02:39 +0000326--></p>
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000327</div>
328
329
330<!--=========================================================================-->
331<div class="doc_subsection">
332<a name="ldc">LLVM D Compiler</a>
333</div>
334
335<div class="doc_text">
336<p>
Chris Lattnere5236102010-03-17 04:02:39 +0000337Need update.
338<!--
Chris Lattner47202c32009-03-02 02:37:32 +0000339<a href="http://www.dsource.org/projects/ldc">LDC</a> is an implementation of
340the D Programming Language using the LLVM optimizer and code generator.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000341The LDC project works great with the LLVM 2.6 release. General improvements in
John Criswellaea8c752009-03-02 15:28:15 +0000342this
Chris Lattner47202c32009-03-02 02:37:32 +0000343cycle have included new inline asm constraint handling, better debug info
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000344support, general bug fixes and better x86-64 support. This has allowed
345some major improvements in LDC, getting it much closer to being as
Chris Lattnere5236102010-03-17 04:02:39 +0000346fully featured as the original DMD compiler from DigitalMars.-->
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000347</p>
348</div>
349
Chris Lattner1ad599a2009-02-28 18:58:01 +0000350<!--=========================================================================-->
351<div class="doc_subsection">
352<a name="RoadsendPHP">Roadsend PHP</a>
353</div>
354
355<div class="doc_text">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000356<p>
Chris Lattnere5236102010-03-17 04:02:39 +0000357Need update.
358<!--
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000359<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
Chris Lattner9e08de12009-03-02 19:07:24 +0000360source implementation of the PHP programming
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000361language that uses LLVM for its optimizer, JIT and static compiler. This is a
Chris Lattnere5236102010-03-17 04:02:39 +0000362reimplementation of an earlier project that is now based on LLVM.
363--> </p>
Chris Lattner1ad599a2009-02-28 18:58:01 +0000364</div>
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000365
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000366<!--=========================================================================-->
367<div class="doc_subsection">
368<a name="UnladenSwallow">Unladen Swallow</a>
369</div>
370
371<div class="doc_text">
372<p>
Chris Lattnere5236102010-03-17 04:02:39 +0000373Need update.
374<!--
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000375<a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
376branch of <a href="http://python.org/">Python</a> intended to be fully
377compatible and significantly faster. It uses LLVM's optimization passes and JIT
Chris Lattnere5236102010-03-17 04:02:39 +0000378compiler.-->
379</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000380</div>
381
382<!--=========================================================================-->
383<div class="doc_subsection">
384<a name="llvm-lua">llvm-lua</a>
385</div>
386
387<div class="doc_text">
388<p>
Chris Lattnere5236102010-03-17 04:02:39 +0000389Need update.
390<!--
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000391<a href="http://code.google.com/p/llvm-lua/">LLVM-Lua</a> uses LLVM to add JIT
392and static compiling support to the Lua VM. Lua bytecode is analyzed to
393remove type checks, then LLVM is used to compile the bytecode down to machine
Chris Lattnere5236102010-03-17 04:02:39 +0000394code.-->
395</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000396</div>
397
398<!--=========================================================================-->
399<div class="doc_subsection">
400<a name="icedtea">IcedTea Java Virtual Machine Implementation</a>
401</div>
402
403<div class="doc_text">
404<p>
Chris Lattnere5236102010-03-17 04:02:39 +0000405Need update.
406<!--
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000407<a href="http://icedtea.classpath.org/wiki/Main_Page">IcedTea</a> provides a
408harness to build OpenJDK using only free software build tools and to provide
409replacements for the not-yet free parts of OpenJDK. One of the extensions that
410IcedTea provides is a new JIT compiler named <a
411href="http://icedtea.classpath.org/wiki/ZeroSharkFaq">Shark</a> which uses LLVM
412to provide native code generation without introducing processor-dependent
Chris Lattnere5236102010-03-17 04:02:39 +0000413code.-->
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000414</p>
415</div>
416
417
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000418
419<!-- *********************************************************************** -->
420<div class="doc_section">
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000421 <a name="whatsnew">What's New in LLVM 2.7?</a>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000422</div>
423<!-- *********************************************************************** -->
424
Chris Lattner5cce7a52008-06-08 22:59:35 +0000425<div class="doc_text">
426
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000427<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattner92eacf82008-10-13 17:57:36 +0000428minor improvements. Some of the major improvements and new features are listed
429in this section.
Chris Lattner5cce7a52008-06-08 22:59:35 +0000430</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000431
Chris Lattner5cce7a52008-06-08 22:59:35 +0000432</div>
433
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000434<!--=========================================================================-->
Chris Lattnerf65224f2008-06-08 21:34:41 +0000435<div class="doc_subsection">
Chris Lattnere0798082008-02-06 18:00:06 +0000436<a name="majorfeatures">Major New Features</a>
437</div>
438
439<div class="doc_text">
440
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000441<p>LLVM 2.7 includes several major new capabilities:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000442
443<ul>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000444<li>...</li>
Chris Lattner5ba16862008-02-10 08:18:42 +0000445</ul>
446
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000447Extensible metadata solid.
448
449Debug info improvements: using metadata instead of llvm.dbg global variables.
450This brings several enhancements including improved compile times.
451
452New instruction selector.
453GHC Haskell ABI/ calling conv support.
454Pre-Alpha support for unions in IR.
455New InlineHint and StackAlignment function attributes
456Code generator MC'ized except for debug info and EH.
457New SCEV AA pass: -scev-aa
458Inliner reuses arrays allocas when inlining multiple callers to reduce stack usage.
459MC encoding and disassembler apis.
460Optimal Edge Profiling?
461Instcombine is now a library, has its own IRBuilder to simplify itself.
462New llvm/Support/Regex.h API. FileCheck now does regex's
Chris Lattner2b656342010-03-17 06:41:58 +0000463Many subtle pointer invalidation bugs in Callgraph have been fixed and it now uses asserting value handles.
464MC Disassembler (with blog post), MCInstPrinter. Many X86 backend and AsmPrinter simplifications
465Various tools like llc and opt now read either .ll or .bc files as input.
466Malloc and free instructions got removed.
467compiler-rt support for ARM.
468completely llvm-gcc NEON support.
469Can transcode from GAS to intel syntax with "llvm-mc foo.s -output-asm-variant=1"
470JIT debug information with GDB 7.0
471New CodeGen Level LICM And CSE (did it make 2.7?)
472CMake can now run tests, what other improvements?
473ARM/Thumb register scavenging improvements?
474New SSAUpdater and MachineSSAUpdater classes for unstructured ssa updating,
475 changed jump threading, GVN, etc to use it which simplified them and speed
476 them up.
Chris Lattner99bfacb2010-03-17 06:42:25 +0000477Combiner-AA improvements, why not on by default?
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000478
Chris Lattner2b656342010-03-17 06:41:58 +0000479CondProp pass removed (functionality merged into jump threading).
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000480AndersAA got removed (from 2.7 or mainline?)
Chris Lattner2b656342010-03-17 06:41:58 +0000481PredSimplify, LoopVR, GVNPRE got removed.
Chris Lattner58b1d0f2010-03-17 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 Lattner2b656342010-03-17 06:41:58 +0000488
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000489</div>
490
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000491<!--=========================================================================-->
492<div class="doc_subsection">
Chris Lattner47202c32009-03-02 02:37:32 +0000493<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerc3649452008-02-10 08:17:19 +0000494</div>
495
496<div class="doc_text">
Chris Lattner0b6ea7a2009-10-13 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 Lattnerc3649452008-02-10 08:17:19 +0000499
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000500<ul>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000501<li>...</li>
Chris Lattnerc3649452008-02-10 08:17:19 +0000502</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000503
Chris Lattnerc3649452008-02-10 08:17:19 +0000504</div>
505
506<!--=========================================================================-->
507<div class="doc_subsection">
Chris Lattner8fda4952008-02-10 07:46:44 +0000508<a name="optimizer">Optimizer Improvements</a>
509</div>
510
511<div class="doc_text">
512
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000513<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattnerea9c2242008-10-13 21:50:36 +0000514release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner8fda4952008-02-10 07:46:44 +0000515
516<ul>
517
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000518<li>...</li>
Chris Lattner47202c32009-03-02 02:37:32 +0000519
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000520</ul>
Chris Lattner47202c32009-03-02 02:37:32 +0000521
Chris Lattner317685c2010-03-01 19:29:17 +0000522<p>Also, -anders-aa was removed</p>
523
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000524</div>
Chris Lattner47202c32009-03-02 02:37:32 +0000525
Chris Lattner47202c32009-03-02 02:37:32 +0000526
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000527<!--=========================================================================-->
528<div class="doc_subsection">
529<a name="executionengine">Interpreter and JIT Improvements</a>
530</div>
Chris Lattnerea9c2242008-10-13 21:50:36 +0000531
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000532<div class="doc_text">
533
534<ul>
Jeffrey Yasskin40715142010-01-29 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 Yasskinc0577082010-02-11 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 Lattner0eef6e42008-06-08 02:45:07 +0000544</ul>
545
546</div>
547
548<!--=========================================================================-->
549<div class="doc_subsection">
Chris Lattner5f393542009-03-02 03:24:11 +0000550<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000551</div>
552
553<div class="doc_text">
554
Mikhail Glushenkovf61066a2009-03-01 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 Lattner0eef6e42008-06-08 02:45:07 +0000558
559<ul>
Chris Lattner5f393542009-03-02 03:24:11 +0000560
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000561<li>...</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000562</ul>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000563</div>
564
Chris Lattner47202c32009-03-02 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 Lattner5f393542009-03-02 03:24:11 +0000575
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000576<li>...</li>
Chris Lattner5f393542009-03-02 03:24:11 +0000577
Chris Lattner47202c32009-03-02 02:37:32 +0000578</ul>
579
Chris Lattner47202c32009-03-02 02:37:32 +0000580</div>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000581
582<!--=========================================================================-->
583<div class="doc_subsection">
Chris Lattnere1fbd752009-02-26 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 Yasskin8ee1b0a2010-01-28 01:14:43 +0000592<li>...</li>
Chris Lattnere1fbd752009-02-26 07:32:11 +0000593</ul>
594
595<p>Things not yet supported:</p>
596
597<ul>
Chris Lattnere1fbd752009-02-26 07:32:11 +0000598<li>Variable arguments.</li>
Chris Lattner5f393542009-03-02 03:24:11 +0000599<li>Interrupts/programs.</li>
Chris Lattnere1fbd752009-02-26 07:32:11 +0000600</ul>
601
602</div>
603
Chris Lattnere1fbd752009-02-26 07:32:11 +0000604<!--=========================================================================-->
605<div class="doc_subsection">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000606<a name="ARM">ARM Target Improvements</a>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000607</div>
608
609<div class="doc_text">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000610<p>New features of the ARM target include:
611</p>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000612
613<ul>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000614
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000615<li>...</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000616</ul>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000617
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000618
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000619</div>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000620
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000621<!--=========================================================================-->
622<div class="doc_subsection">
623<a name="OtherTarget">Other Target Specific Improvements</a>
624</div>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000625
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000626<div class="doc_text">
627<p>New features of other targets include:
628</p>
629
630<ul>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000631<li>...</li>
Chris Lattner0b6ea7a2009-10-13 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 Yasskin8ee1b0a2010-01-28 01:14:43 +0000648<li>...</li>
Chris Lattner0b6ea7a2009-10-13 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 Yasskin8ee1b0a2010-01-28 01:14:43 +0000663<li>...</li>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000664</ul>
665
666</div>
667
Chris Lattnere45f18b2008-06-05 08:02:49 +0000668
669<!--=========================================================================-->
670<div class="doc_subsection">
Chris Lattner92eacf82008-10-13 17:57:36 +0000671<a name="changes">Major Changes and Removed Features</a>
672</div>
673
674<div class="doc_text">
675
Chris Lattnercc64a322008-10-13 22:06:31 +0000676<p>If you're already an LLVM user or developer with out-of-tree changes based
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000677on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading
Chris Lattnercc64a322008-10-13 22:06:31 +0000678from the previous release.</p>
Chris Lattner92eacf82008-10-13 17:57:36 +0000679
680<ul>
Jeffrey Yasskin260af332010-02-09 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 Lattnercc64a322008-10-13 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 Yasskin2ca16212010-01-28 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 Dunbar61f41422010-02-10 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 Dunbar369889a2010-02-14 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 Sandsdd29fc82010-02-17 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 Patel0e3da1a2008-10-14 20:03:43 +0000721</ul>
Chris Lattner92eacf82008-10-13 17:57:36 +0000722
Chris Lattner92eacf82008-10-13 17:57:36 +0000723</div>
724
725
726
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000727<!-- *********************************************************************** -->
728<div class="doc_section">
729 <a name="portability">Portability and Supported Platforms</a>
730</div>
731<!-- *********************************************************************** -->
732
733<div class="doc_text">
734
735<p>LLVM is known to work on the following platforms:</p>
736
737<ul>
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000738<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000739 Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like
740 systems).</li>
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000741<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000742 and 64-bit modes.</li>
Chris Lattnere0798082008-02-06 18:00:06 +0000743<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +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 Lattner9235ce52009-10-16 16:30:58 +0000746<li>Sun x86 and AMD64 machines running Solaris 10, OpenSolaris 0906.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000747<li>Alpha-based machines running Debian GNU/Linux.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000748</ul>
749
Chris Lattnerba948522008-06-05 06:57:39 +0000750<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Dan Gohmanf17a25c2007-07-18 16:29:46 +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>
754
755</div>
756
757<!-- *********************************************************************** -->
758<div class="doc_section">
759 <a name="knownproblems">Known Problems</a>
760</div>
761<!-- *********************************************************************** -->
762
763<div class="doc_text">
764
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000765<p>This section contains significant known problems with the LLVM system,
Chris Lattnerb1ad47c2008-11-10 05:40:34 +0000766listed by component. If you run into a problem, please check the <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000767href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
768there isn't already one.</p>
769
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000770<ul>
771<li>The llvm-gcc bootstrap will fail with some versions of binutils (e.g. 2.15)
772 with a message of "<tt><a href="http://llvm.org/PR5004">Error: can not do 8
773 byte pc-relative relocation</a></tt>" when building C++ code. We intend to
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000774 fix this on mainline, but a workaround is to upgrade to binutils 2.17 or
775 later.</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000776
777<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
778using the stock GCC 3.x.x series 'out the box',
Chris Lattnerc09ffd22009-11-03 21:50:09 +0000779See: <a href="GettingStarted.html#brokengcc">Broken versions of GCC and other tools</a>.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000780However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
781for x86/x86-64 has been made available from the third party AuroraUX Project
782that has been meticulously tested for bootstrapping LLVM &amp; Clang.</li>
783</ul>
784
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000785</div>
786
787<!-- ======================================================================= -->
788<div class="doc_subsection">
789 <a name="experimental">Experimental features included with this release</a>
790</div>
791
792<div class="doc_text">
793
794<p>The following components of this LLVM release are either untested, known to
795be broken or unreliable, or are in early development. These components should
796not be relied on, and bugs should not be filed against them, but they may be
797useful to some people. In particular, if you would like to work on one of these
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000798components, please contact us on the <a
799href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000800
801<ul>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000802<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430 and SystemZ backends are
803 experimental.</li>
Bill Wendling9c7c4382009-03-02 07:54:14 +0000804<li>The <tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000805 supported value for this option. The MachO writer is experimental, and
806 works much better in mainline SVN.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000807</ul>
808
809</div>
810
811<!-- ======================================================================= -->
812<div class="doc_subsection">
813 <a name="x86-be">Known problems with the X86 back-end</a>
814</div>
815
816<div class="doc_text">
817
818<ul>
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000819 <li>The X86 backend does not yet support
820 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
821 floating point stack</a>. It supports the 'f' and 't' constraints, but not
822 'u'.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000823 <li>The X86 backend generates inefficient floating point code when configured
824 to generate code for systems that don't have SSE2.</li>
Duncan Sands8b4f3772008-06-08 19:38:43 +0000825 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswellaea8c752009-03-02 15:28:15 +0000826 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
827 runtime currently due
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000828 to <a href="http://llvm.org/PR2255">several</a>
John Criswellaea8c752009-03-02 15:28:15 +0000829 <a href="http://llvm.org/PR2257">bugs</a> and due to lack of support for
830 the
831 'u' inline assembly constraint and for X87 floating point inline assembly.</li>
Dan Gohman3882ecb2008-06-08 23:05:11 +0000832 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner47202c32009-03-02 02:37:32 +0000833 <tt>va_arg</tt>. Currently, the llvm-gcc and front-ends support variadic
Dan Gohman3882ecb2008-06-08 23:05:11 +0000834 argument constructs on X86-64 by lowering them manually.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000835</ul>
836
837</div>
838
839<!-- ======================================================================= -->
840<div class="doc_subsection">
841 <a name="ppc-be">Known problems with the PowerPC back-end</a>
842</div>
843
844<div class="doc_text">
845
846<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000847<li>The Linux PPC32/ABI support needs testing for the interpreter and static
848compilation, and lacks support for debug information.</li>
849</ul>
850
851</div>
852
853<!-- ======================================================================= -->
854<div class="doc_subsection">
855 <a name="arm-be">Known problems with the ARM back-end</a>
856</div>
857
858<div class="doc_text">
859
860<ul>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000861<li>Support for the Advanced SIMD (Neon) instruction set is still incomplete
862and not well tested. Some features may not work at all, and the code quality
863may be poor in some cases.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000864<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000865processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000866results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswellaea8c752009-03-02 15:28:15 +0000867<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000868</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000869</ul>
870
871</div>
872
873<!-- ======================================================================= -->
874<div class="doc_subsection">
875 <a name="sparc-be">Known problems with the SPARC back-end</a>
876</div>
877
878<div class="doc_text">
879
880<ul>
John Criswellaea8c752009-03-02 15:28:15 +0000881<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000882 support the 64-bit SPARC ABI (-m64).</li>
883</ul>
884
885</div>
886
887<!-- ======================================================================= -->
888<div class="doc_subsection">
Bruno Cardoso Lopes62d45d72008-10-25 14:56:26 +0000889 <a name="mips-be">Known problems with the MIPS back-end</a>
890</div>
891
892<div class="doc_text">
893
894<ul>
Bruno Cardoso Lopes62d45d72008-10-25 14:56:26 +0000895<li>64-bit MIPS targets are not supported yet.</li>
896</ul>
897
898</div>
899
900<!-- ======================================================================= -->
901<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000902 <a name="alpha-be">Known problems with the Alpha back-end</a>
903</div>
904
905<div class="doc_text">
906
907<ul>
908
909<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
910appropriate nops inserted to ensure restartability.</li>
911
912</ul>
913</div>
914
915<!-- ======================================================================= -->
916<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000917 <a name="c-be">Known problems with the C back-end</a>
918</div>
919
920<div class="doc_text">
921
922<ul>
Chris Lattner499c07c2008-06-05 06:35:40 +0000923<li><a href="http://llvm.org/PR802">The C backend has only basic support for
924 inline assembly code</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000925<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
926 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greife33c5322009-03-02 12:02:51 +0000927 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandsbd0ad6e2008-02-10 13:40:55 +0000928<li>The C backend does not support all exception handling constructs.</li>
Duncan Sandse6e264c2009-02-25 11:51:54 +0000929<li>The C backend does not support arbitrary precision integers.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000930</ul>
931
932</div>
933
934
935<!-- ======================================================================= -->
936<div class="doc_subsection">
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000937 <a name="c-fe">Known problems with the llvm-gcc C and C++ front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000938</div>
939
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000940<div class="doc_text">
941
Chris Lattner499c07c2008-06-05 06:35:40 +0000942<p>The only major language feature of GCC not supported by llvm-gcc is
943 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
944 are only supported on some targets. For example, trampolines are only
Duncan Sandsa73561c2008-06-08 20:18:35 +0000945 supported on some targets (these are used when you take the address of a
946 nested function).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000947
Chris Lattner499c07c2008-06-05 06:35:40 +0000948<p>If you run into GCC extensions which are not supported, please let us know.
949</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000950
951</div>
952
953<!-- ======================================================================= -->
954<div class="doc_subsection">
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000955 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
956</div>
957
958<div class="doc_text">
Gabor Greif1fc8fbc2008-11-04 21:50:59 +0000959<ul>
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000960<li>Fortran support generally works, but there are still several unresolved bugs
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000961 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
962 tools/gfortran component for details.</li>
Gabor Greif1fc8fbc2008-11-04 21:50:59 +0000963</ul>
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000964</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000965
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000966<!-- ======================================================================= -->
967<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000968 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000969</div>
970
971<div class="doc_text">
John Criswellaea8c752009-03-02 15:28:15 +0000972The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
973technology, and problems should be expected.
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000974<ul>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000975<li>The Ada front-end currently only builds on X86-32. This is mainly due
John Criswellaea8c752009-03-02 15:28:15 +0000976to lack of trampoline support (pointers to nested functions) on other platforms.
977However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000978which does support trampolines.</li>
979<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
Duncan Sandsf73473e2009-02-25 11:59:06 +0000980This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
981exception handling, which is used internally by the compiler.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000982Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
Duncan Sands2dbc2e82008-10-13 17:27:23 +0000983<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
984and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sandsf73473e2009-02-25 11:59:06 +0000985(c380004 also fails with gcc-4.2 mainline).
986If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
987causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sandsc2a29a02009-03-02 16:35:57 +0000988<li>Some GCC specific Ada tests continue to crash the compiler.</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000989<li>The <tt>-E</tt> binder option (exception backtraces)
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000990<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000991crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000992<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
993or finish at a non-byte offset</a> in a record. Workaround: do not pack records
994or use representation clauses that result in a field of a non-discrete type
995starting or finishing in the middle of a byte.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000996<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
997'main' as generated by the Ada binder to be invalid</a>.
998Workaround: hand edit the file to use pointers for <tt>argv</tt> and
999<tt>envp</tt> rather than integers.</li>
1000<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
1001ignored</a>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +00001002</ul>
1003</div>
1004
Chris Lattner0b6ea7a2009-10-13 17:48:04 +00001005<!-- ======================================================================= -->
1006<div class="doc_subsection">
1007 <a name="ocaml-bindings">Known problems with the O'Caml bindings</a>
1008</div>
1009
1010<div class="doc_text">
1011
1012<p>The <tt>Llvm.Linkage</tt> module is broken, and has incorrect values. Only
1013<tt>Llvm.Linkage.External</tt>, <tt>Llvm.Linkage.Available_externally</tt>, and
1014<tt>Llvm.Linkage.Link_once</tt> will be correct. If you need any of the other linkage
1015modes, you'll have to write an external C library in order to expose the
1016functionality. This has been fixed in the trunk.</p>
1017</div>
1018
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001019<!-- *********************************************************************** -->
1020<div class="doc_section">
1021 <a name="additionalinfo">Additional Information</a>
1022</div>
1023<!-- *********************************************************************** -->
1024
1025<div class="doc_text">
1026
1027<p>A wide variety of additional information is available on the <a
1028href="http://llvm.org">LLVM web page</a>, in particular in the <a
1029href="http://llvm.org/docs/">documentation</a> section. The web page also
1030contains versions of the API documentation which is up-to-date with the
1031Subversion version of the source code.
1032You can access versions of these documents specific to this release by going
1033into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
1034
1035<p>If you have any questions or comments about LLVM, please feel free to contact
1036us via the <a href="http://llvm.org/docs/#maillist"> mailing
1037lists</a>.</p>
1038
1039</div>
1040
1041<!-- *********************************************************************** -->
1042
1043<hr>
1044<address>
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1050 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
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