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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>
Daniel Dunbar29f1e722010-03-25 16:09:18 +0000130<li>FIXME: C++! Include a link to cxx_compatibility.html</li>
131
132<li>FIXME: Static Analyzer improvements?</li>
133
134<li>CIndex API and Python bindings: Clang now includes a C API as part of the
135CIndex library. Although we make make some changes to the API in the future, it
136is intended to be stable and has been designed for use by external projects. See
137the Clang
138doxygen <a href="http://clang.llvm.org/doxygen/group__CINDEX.html">CIndex</a>
139documentation for more details. The CIndex API also includings an preliminary
140set of Python bindings.</li>
141
142<li>ARM Support: Clang now has ABI support for both the Darwin and Linux ARM
143ABIs. Coupled with many improvements to the LLVM ARM backend, Clang is now
144suitable for use as a a beta quality ARM compiler.</li>
Bill Wendlinga8fb81d2009-03-02 04:28:18 +0000145</ul>
Chris Lattnera3c683b2008-10-13 18:11:54 +0000146</div>
147
148<!--=========================================================================-->
149<div class="doc_subsection">
150<a name="clangsa">Clang Static Analyzer</a>
151</div>
152
153<div class="doc_text">
154
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000155<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 +0000156includes an early stage static source code analysis tool for <a
157href="http://clang.llvm.org/StaticAnalysis.html">automatically finding bugs</a>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000158in C and Objective-C programs. The tool performs checks to find
Ted Kremeneka0d77d72009-02-27 07:01:32 +0000159bugs that occur on a specific path within a program.</p>
Chris Lattnerc2d84672008-10-14 00:52:49 +0000160
Chris Lattnere5236102010-03-17 04:02:39 +0000161<p>In the LLVM 2.7 time-frame, the analyzer core has sprouted legs and...</p>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000162
163</div>
164
Chris Lattner78a130b2008-10-13 18:01:01 +0000165<!--=========================================================================-->
166<div class="doc_subsection">
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000167<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattner78a130b2008-10-13 18:01:01 +0000168</div>
169
170<div class="doc_text">
171<p>
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000172The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000173a JVM and a CLI Virtual Machine (Microsoft .NET is an
174implementation of the CLI) using LLVM for static and just-in-time
175compilation.</p>
Chris Lattner78a130b2008-10-13 18:01:01 +0000176
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000177<p>
Chris Lattnerd5b62522010-03-29 18:34:13 +0000178With the release of LLVM 2.7, VMKit has shifted to a great framework for writing
179virtual machines. VMKit now offers precise and efficient garbage collection with
180multi-threading support, thanks to the MMTk memory management toolkit, as well
181as just in time and ahead of time compilation with LLVM. The major changes in
182VMKit 0.27 are:</p>
Chris Lattner78a130b2008-10-13 18:01:01 +0000183
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000184<ul>
185
Chris Lattnerd5b62522010-03-29 18:34:13 +0000186<li>Garbage collection: VMKit now uses the MMTk toolkit for garbage collectors.
187 The first collector to be ported is the MarkSweep collector, which is precise,
188 and drastically improves the performance of VMKit.</li>
189<li>Line number information in the JVM: by using the debug metadata of LLVM, the
190 JVM now supports precise line number information, useful when printing a stack
191 trace.</li>
192<li>Interface calls in the JVM: we implemented a variant of the Interface Method
193 Table technique for interface calls in the JVM.
194</li>
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000195
196</ul>
Chris Lattner78a130b2008-10-13 18:01:01 +0000197</div>
198
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000199
200<!--=========================================================================-->
201<div class="doc_subsection">
202<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
203</div>
204
205<div class="doc_text">
206<p>
207The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
208is a simple library that provides an implementation of the low-level
209target-specific hooks required by code generation and other runtime components.
210For example, when compiling for a 32-bit target, converting a double to a 64-bit
211unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
212function. The compiler-rt library provides highly optimized implementations of
213this and other low-level routines (some are 3x faster than the equivalent
214libgcc routines).</p>
215
216<p>
217All of the code in the compiler-rt project is available under the standard LLVM
218License, a "BSD-style" license.</p>
219
220</div>
221
222<!--=========================================================================-->
223<div class="doc_subsection">
Duncan Sands2d9c3082010-04-02 09:23:15 +0000224<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000225</div>
226
227<div class="doc_text">
228<p>
Duncan Sands2d9c3082010-04-02 09:23:15 +0000229<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
230gcc-4.5. Unlike llvm-gcc, which makes many intrusive changes to the underlying
231gcc-4.2 code, dragonegg in theory does not require any gcc-4.5 modifications
232whatsoever (currently one small patch is needed). This is thanks to the new
233<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>, which
234makes it possible to modify the behaviour of gcc at runtime by loading a plugin,
235which is nothing more than a dynamic library which conforms to the gcc plugin
236interface. DragonEgg is a gcc plugin that causes the LLVM optimizers to be run
237instead of the gcc optimizers, and the LLVM code generators instead of the gcc
238code generators, just like llvm-gcc. To use it, you add
239"-fplugin=path/dragonegg.so" to the gcc-4.5 command line, and gcc-4.5 magically
240becomes llvm-gcc-4.5!
241</p>
242
243<p>
244DragonEgg is still a work in progress. Currently C works very well, while C++,
245Ada and Fortran work fairly well. All other languages either don't work at all,
246or only work poorly. For the moment only the x86-32 and x86-64 targets are
247supported, and only on linux.
248</p>
249
250<p>
251DragonEgg has not yet been released. Once gcc-4.5 has been released, dragonegg
252will probably be released as part of the following LLVM release.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000253</p>
254
255</div>
256
257
258<!--=========================================================================-->
259<div class="doc_subsection">
260<a name="mc">llvm-mc: Machine Code Toolkit</a>
261</div>
262
263<div class="doc_text">
264<p>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000265The LLVM Machine Code (MC) Toolkit project is ...
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000266</p>
267
268</div>
269
270
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000271<!-- *********************************************************************** -->
272<div class="doc_section">
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000273 <a name="externalproj">External Open Source Projects Using LLVM 2.7</a>
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000274</div>
275<!-- *********************************************************************** -->
276
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000277<div class="doc_text">
278
279<p>An exciting aspect of LLVM is that it is used as an enabling technology for
280 a lot of other language and tools projects. This section lists some of the
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000281 projects that have already been updated to work with LLVM 2.7.</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000282</div>
283
284
285<!--=========================================================================-->
286<div class="doc_subsection">
287<a name="Rubinius">Rubinius</a>
288</div>
289
290<div class="doc_text">
Chris Lattnere5236102010-03-17 04:02:39 +0000291Need update.
292<!--
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000293<p><a href="http://github.com/evanphx/rubinius">Rubinius</a> is an environment
294for running Ruby code which strives to write as much of the core class
295implementation in Ruby as possible. Combined with a bytecode interpreting VM, it
296uses LLVM to optimize and compile ruby code down to machine code. Techniques
297such as type feedback, method inlining, and uncommon traps are all used to
298remove dynamism from ruby execution and increase performance.</p>
299
300<p>Since LLVM 2.5, Rubinius has made several major leaps forward, implementing
301a counter based JIT, type feedback and speculative method inlining.
Chris Lattnere5236102010-03-17 04:02:39 +0000302-->
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000303</p>
304
305</div>
306
307<!--=========================================================================-->
308<div class="doc_subsection">
309<a name="macruby">MacRuby</a>
310</div>
311
312<div class="doc_text">
313
314<p>
Chris Lattnere5236102010-03-17 04:02:39 +0000315Need update.
316<!--
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000317<a href="http://macruby.org">MacRuby</a> is an implementation of Ruby on top of
318core Mac OS X technologies, such as the Objective-C common runtime and garbage
319collector and the CoreFoundation framework. It is principally developed by
320Apple and aims at enabling the creation of full-fledged Mac OS X applications.
321</p>
322
323<p>
324MacRuby uses LLVM for optimization passes, JIT and AOT compilation of Ruby
325expressions. It also uses zero-cost DWARF exceptions to implement Ruby exception
Chris Lattnere5236102010-03-17 04:02:39 +0000326handling.--> </p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000327
328</div>
329
330
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000331<!--=========================================================================-->
332<div class="doc_subsection">
333<a name="pure">Pure</a>
334</div>
335
336<div class="doc_text">
337<p>
Chris Lattner47202c32009-03-02 02:37:32 +0000338<a href="http://pure-lang.googlecode.com/">Pure</a>
339is an algebraic/functional programming language based on term rewriting.
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000340Programs are collections of equations which are used to evaluate expressions in
341a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000342lexical closures, a hygienic macro system (also based on term rewriting),
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000343built-in list and matrix support (including list and matrix comprehensions) and
344an easy-to-use C interface. The interpreter uses LLVM as a backend to
345 JIT-compile Pure programs to fast native code.</p>
346
Chris Lattner1f8dc512010-03-17 17:25:49 +0000347<p>Pure versions 0.43 and later have been tested and are known to work with
348LLVM 2.7 (and continue to work with older LLVM releases >= 2.5).</p>
349
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000350</div>
351
352
353<!--=========================================================================-->
354<div class="doc_subsection">
355<a name="ldc">LLVM D Compiler</a>
356</div>
357
358<div class="doc_text">
359<p>
Chris Lattnere5236102010-03-17 04:02:39 +0000360Need update.
361<!--
Chris Lattner47202c32009-03-02 02:37:32 +0000362<a href="http://www.dsource.org/projects/ldc">LDC</a> is an implementation of
363the D Programming Language using the LLVM optimizer and code generator.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000364The LDC project works great with the LLVM 2.6 release. General improvements in
John Criswellaea8c752009-03-02 15:28:15 +0000365this
Chris Lattner47202c32009-03-02 02:37:32 +0000366cycle have included new inline asm constraint handling, better debug info
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000367support, general bug fixes and better x86-64 support. This has allowed
368some major improvements in LDC, getting it much closer to being as
Chris Lattnere5236102010-03-17 04:02:39 +0000369fully featured as the original DMD compiler from DigitalMars.-->
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000370</p>
371</div>
372
Chris Lattner1ad599a2009-02-28 18:58:01 +0000373<!--=========================================================================-->
374<div class="doc_subsection">
375<a name="RoadsendPHP">Roadsend PHP</a>
376</div>
377
378<div class="doc_text">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000379<p>
380<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
Chris Lattner9e08de12009-03-02 19:07:24 +0000381source implementation of the PHP programming
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000382language that uses LLVM for its optimizer, JIT and static compiler. This is a
Chris Lattnere5236102010-03-17 04:02:39 +0000383reimplementation of an earlier project that is now based on LLVM.
Chris Lattner1f8dc512010-03-17 17:25:49 +0000384</p>
Chris Lattner1ad599a2009-02-28 18:58:01 +0000385</div>
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000386
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000387<!--=========================================================================-->
388<div class="doc_subsection">
389<a name="UnladenSwallow">Unladen Swallow</a>
390</div>
391
392<div class="doc_text">
393<p>
394<a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
395branch of <a href="http://python.org/">Python</a> intended to be fully
396compatible and significantly faster. It uses LLVM's optimization passes and JIT
Chris Lattnerd7db82c2010-03-18 06:52:15 +0000397compiler.
Chris Lattnere5236102010-03-17 04:02:39 +0000398</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000399</div>
400
401<!--=========================================================================-->
402<div class="doc_subsection">
403<a name="llvm-lua">llvm-lua</a>
404</div>
405
406<div class="doc_text">
407<p>
Chris Lattnere5236102010-03-17 04:02:39 +0000408Need update.
409<!--
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000410<a href="http://code.google.com/p/llvm-lua/">LLVM-Lua</a> uses LLVM to add JIT
411and static compiling support to the Lua VM. Lua bytecode is analyzed to
412remove type checks, then LLVM is used to compile the bytecode down to machine
Chris Lattnere5236102010-03-17 04:02:39 +0000413code.-->
414</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000415</div>
416
417<!--=========================================================================-->
418<div class="doc_subsection">
419<a name="icedtea">IcedTea Java Virtual Machine Implementation</a>
420</div>
421
422<div class="doc_text">
423<p>
Chris Lattnere5236102010-03-17 04:02:39 +0000424Need update.
425<!--
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000426<a href="http://icedtea.classpath.org/wiki/Main_Page">IcedTea</a> provides a
427harness to build OpenJDK using only free software build tools and to provide
428replacements for the not-yet free parts of OpenJDK. One of the extensions that
429IcedTea provides is a new JIT compiler named <a
430href="http://icedtea.classpath.org/wiki/ZeroSharkFaq">Shark</a> which uses LLVM
431to provide native code generation without introducing processor-dependent
Chris Lattnere5236102010-03-17 04:02:39 +0000432code.-->
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000433</p>
434</div>
435
436
Chris Lattner49894862010-03-29 17:50:39 +0000437<!--=========================================================================-->
438<div class="doc_subsection">
439<a name="tce">TTA-based Codesign Environment (TCE)</a>
440</div>
441
442<div class="doc_text">
443<p>
444<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing
445application-specific processors (ASP) based on the Transport triggered
446architecture (TTA). The toolset provides a complete co-design flow from C/C++
447programs down to synthesizable VHDL and parallel program binaries. Processor
448customization points include the register files, function units, supported
449operations, and the interconnection network.</p>
450
451<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target
452independent optimizations and also for parts of code generation. It generates
453new LLVM-based code generators "on the fly" for the designed TTA processors and
454loads them in to the compiler backend as runtime libraries to avoid per-target
455recompilation of larger parts of the compiler chain.</p>
456
457</div>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000458
459<!-- *********************************************************************** -->
460<div class="doc_section">
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000461 <a name="whatsnew">What's New in LLVM 2.7?</a>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000462</div>
463<!-- *********************************************************************** -->
464
Chris Lattner5cce7a52008-06-08 22:59:35 +0000465<div class="doc_text">
466
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000467<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattner92eacf82008-10-13 17:57:36 +0000468minor improvements. Some of the major improvements and new features are listed
469in this section.
Chris Lattner5cce7a52008-06-08 22:59:35 +0000470</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000471
Chris Lattner5cce7a52008-06-08 22:59:35 +0000472</div>
473
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000474<!--=========================================================================-->
Chris Lattnerf65224f2008-06-08 21:34:41 +0000475<div class="doc_subsection">
Chris Lattnere0798082008-02-06 18:00:06 +0000476<a name="majorfeatures">Major New Features</a>
477</div>
478
479<div class="doc_text">
480
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000481<p>LLVM 2.7 includes several major new capabilities:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000482
483<ul>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000484<li>...</li>
Chris Lattner5ba16862008-02-10 08:18:42 +0000485</ul>
486
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000487Extensible metadata solid.
488
489Debug info improvements: using metadata instead of llvm.dbg global variables.
490This brings several enhancements including improved compile times.
491
492New instruction selector.
493GHC Haskell ABI/ calling conv support.
494Pre-Alpha support for unions in IR.
495New InlineHint and StackAlignment function attributes
496Code generator MC'ized except for debug info and EH.
497New SCEV AA pass: -scev-aa
498Inliner reuses arrays allocas when inlining multiple callers to reduce stack usage.
499MC encoding and disassembler apis.
500Optimal Edge Profiling?
501Instcombine is now a library, has its own IRBuilder to simplify itself.
502New llvm/Support/Regex.h API. FileCheck now does regex's
Chris Lattner2b656342010-03-17 06:41:58 +0000503Many subtle pointer invalidation bugs in Callgraph have been fixed and it now uses asserting value handles.
504MC Disassembler (with blog post), MCInstPrinter. Many X86 backend and AsmPrinter simplifications
505Various tools like llc and opt now read either .ll or .bc files as input.
Chris Lattner120eabd2010-03-29 18:42:42 +0000506Malloc and free instructions got removed, along with LowerAllocations pass.
Chris Lattner2b656342010-03-17 06:41:58 +0000507compiler-rt support for ARM.
508completely llvm-gcc NEON support.
509Can transcode from GAS to intel syntax with "llvm-mc foo.s -output-asm-variant=1"
510JIT debug information with GDB 7.0
Chris Lattner27b5bd52010-03-17 18:15:52 +0000511New CodeGen Level CSE
Chris Lattner2b656342010-03-17 06:41:58 +0000512CMake can now run tests, what other improvements?
Chris Lattner27b5bd52010-03-17 18:15:52 +0000513ARM/Thumb using reg scavenging for stack object address materialization (PEI).
Chris Lattner2b656342010-03-17 06:41:58 +0000514New SSAUpdater and MachineSSAUpdater classes for unstructured ssa updating,
515 changed jump threading, GVN, etc to use it which simplified them and speed
516 them up.
Chris Lattner99bfacb2010-03-17 06:42:25 +0000517Combiner-AA improvements, why not on by default?
Chris Lattner27b5bd52010-03-17 18:15:52 +0000518Pre-regalloc tail duplication
519x86 sibcall optimization
520New LSR with full strength reduction mode
521The most awesome sext / zext optimization pass. ?
522
Chris Lattner1071dbb2010-03-29 18:39:28 +0000523The ARM backend now has good support for ARMv4 backend (tested on StrongARM
524 hardware), previously only supported ARMv4T and newer.
525
Chris Lattner27b5bd52010-03-17 18:15:52 +0000526
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000527
Chris Lattner120eabd2010-03-29 18:42:42 +0000528Defaults to RTTI off, packagers should build with make REQUIRE_RTTI=1.
Chris Lattner2b656342010-03-17 06:41:58 +0000529CondProp pass removed (functionality merged into jump threading).
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000530AndersAA got removed (from 2.7 or mainline?)
Chris Lattner2b656342010-03-17 06:41:58 +0000531PredSimplify, LoopVR, GVNPRE got removed.
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000532LLVM command line tools now overwrite their output, before they would only do this with -f.
533DOUT removed, use DEBUG(errs() instead.
534Much stuff converted to use raw_ostream instead of std::ostream.
535TargetAsmInfo renamed to MCAsmInfo
536llvm/ADT/iterator.h gone.
537
Chris Lattner2b656342010-03-17 06:41:58 +0000538
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000539</div>
540
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000541<!--=========================================================================-->
542<div class="doc_subsection">
Chris Lattner47202c32009-03-02 02:37:32 +0000543<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerc3649452008-02-10 08:17:19 +0000544</div>
545
546<div class="doc_text">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000547<p>LLVM IR has several new features for better support of new targets and that
548expose new optimization opportunities:</p>
Chris Lattnerc3649452008-02-10 08:17:19 +0000549
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000550<ul>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000551<li>...</li>
Chris Lattnerc3649452008-02-10 08:17:19 +0000552</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000553
Chris Lattnerc3649452008-02-10 08:17:19 +0000554</div>
555
556<!--=========================================================================-->
557<div class="doc_subsection">
Chris Lattner8fda4952008-02-10 07:46:44 +0000558<a name="optimizer">Optimizer Improvements</a>
559</div>
560
561<div class="doc_text">
562
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000563<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattnerea9c2242008-10-13 21:50:36 +0000564release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner8fda4952008-02-10 07:46:44 +0000565
566<ul>
567
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000568<li>...</li>
Chris Lattner47202c32009-03-02 02:37:32 +0000569
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000570</ul>
Chris Lattner47202c32009-03-02 02:37:32 +0000571
Chris Lattner317685c2010-03-01 19:29:17 +0000572<p>Also, -anders-aa was removed</p>
573
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000574</div>
Chris Lattner47202c32009-03-02 02:37:32 +0000575
Chris Lattner47202c32009-03-02 02:37:32 +0000576
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000577<!--=========================================================================-->
578<div class="doc_subsection">
579<a name="executionengine">Interpreter and JIT Improvements</a>
580</div>
Chris Lattnerea9c2242008-10-13 21:50:36 +0000581
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000582<div class="doc_text">
583
584<ul>
Jeffrey Yasskin40715142010-01-29 19:10:38 +0000585<li>The JIT now <a
586href="http://llvm.org/viewvc/llvm-project?view=rev&revision=85295">defaults
587to compiling eagerly</a> to avoid a race condition in the lazy JIT.
588Clients that still want the lazy JIT can switch it on by calling
589<tt>ExecutionEngine::DisableLazyCompilation(false)</tt>.</li>
Jeffrey Yasskinc0577082010-02-11 01:07:39 +0000590<li>It is now possible to create more than one JIT instance in the same process.
591These JITs can generate machine code in parallel,
592although <a href="http://llvm.org/docs/ProgrammersManual.html#jitthreading">you
593still have to obey the other threading restrictions</a>.</li>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000594</ul>
595
596</div>
597
598<!--=========================================================================-->
599<div class="doc_subsection">
Chris Lattner5f393542009-03-02 03:24:11 +0000600<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000601</div>
602
603<div class="doc_text">
604
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000605<p>We have put a significant amount of work into the code generator
606infrastructure, which allows us to implement more aggressive algorithms and make
607it run faster:</p>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000608
609<ul>
Chris Lattner5f393542009-03-02 03:24:11 +0000610
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000611<li>...</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000612</ul>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000613</div>
614
Chris Lattner47202c32009-03-02 02:37:32 +0000615<!--=========================================================================-->
616<div class="doc_subsection">
617<a name="x86">X86-32 and X86-64 Target Improvements</a>
618</div>
619
620<div class="doc_text">
621<p>New features of the X86 target include:
622</p>
623
624<ul>
Chris Lattner5f393542009-03-02 03:24:11 +0000625
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000626<li>...</li>
Chris Lattner5f393542009-03-02 03:24:11 +0000627
Chris Lattner47202c32009-03-02 02:37:32 +0000628</ul>
629
Chris Lattner47202c32009-03-02 02:37:32 +0000630</div>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000631
632<!--=========================================================================-->
633<div class="doc_subsection">
Chris Lattnere1fbd752009-02-26 07:32:11 +0000634<a name="pic16">PIC16 Target Improvements</a>
635</div>
636
637<div class="doc_text">
638<p>New features of the PIC16 target include:
639</p>
640
641<ul>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000642<li>...</li>
Chris Lattnere1fbd752009-02-26 07:32:11 +0000643</ul>
644
645<p>Things not yet supported:</p>
646
647<ul>
Chris Lattnere1fbd752009-02-26 07:32:11 +0000648<li>Variable arguments.</li>
Chris Lattner5f393542009-03-02 03:24:11 +0000649<li>Interrupts/programs.</li>
Chris Lattnere1fbd752009-02-26 07:32:11 +0000650</ul>
651
652</div>
653
Chris Lattnere1fbd752009-02-26 07:32:11 +0000654<!--=========================================================================-->
655<div class="doc_subsection">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000656<a name="ARM">ARM Target Improvements</a>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000657</div>
658
659<div class="doc_text">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000660<p>New features of the ARM target include:
661</p>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000662
663<ul>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000664
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000665<li>...</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000666</ul>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000667
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000668
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000669</div>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000670
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000671<!--=========================================================================-->
672<div class="doc_subsection">
673<a name="OtherTarget">Other Target Specific Improvements</a>
674</div>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000675
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000676<div class="doc_text">
677<p>New features of other targets include:
678</p>
679
680<ul>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000681<li>...</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000682</ul>
683
684</div>
685
686<!--=========================================================================-->
687<div class="doc_subsection">
688<a name="newapis">New Useful APIs</a>
689</div>
690
691<div class="doc_text">
692
693<p>This release includes a number of new APIs that are used internally, which
694 may also be useful for external clients.
695</p>
696
697<ul>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000698<li>...</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000699</ul>
700
701
702</div>
703
704<!--=========================================================================-->
705<div class="doc_subsection">
706<a name="otherimprovements">Other Improvements and New Features</a>
707</div>
708
709<div class="doc_text">
710<p>Other miscellaneous features include:</p>
711
712<ul>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000713<li>...</li>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000714</ul>
715
716</div>
717
Chris Lattnere45f18b2008-06-05 08:02:49 +0000718
719<!--=========================================================================-->
720<div class="doc_subsection">
Chris Lattner92eacf82008-10-13 17:57:36 +0000721<a name="changes">Major Changes and Removed Features</a>
722</div>
723
724<div class="doc_text">
725
Chris Lattnercc64a322008-10-13 22:06:31 +0000726<p>If you're already an LLVM user or developer with out-of-tree changes based
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000727on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading
Chris Lattnercc64a322008-10-13 22:06:31 +0000728from the previous release.</p>
Chris Lattner92eacf82008-10-13 17:57:36 +0000729
730<ul>
Jeffrey Yasskin260af332010-02-09 23:03:44 +0000731<li>The LLVM interpreter now defaults to <em>not</em> using <tt>libffi</tt> even
732if you have it installed. This makes it more likely that an LLVM built on one
733system will work when copied to a similar system. To use <tt>libffi</tt>,
734configure with <tt>--enable-libffi</tt>.
735</li>
Chris Lattnercc64a322008-10-13 22:06:31 +0000736</ul>
737
738
739<p>In addition, many APIs have changed in this release. Some of the major LLVM
740API changes are:</p>
741
742<ul>
Jeffrey Yasskin2ca16212010-01-28 01:41:20 +0000743<li><tt>ModuleProvider</tt> has been <a
744href="http://llvm.org/viewvc/llvm-project?view=rev&revision=94686">removed</a>
745and its methods moved to <tt>Module</tt> and <tt>GlobalValue</tt>.
746Most clients can remove uses of <tt>ExistingModuleProvider</tt>,
747replace <tt>getBitcodeModuleProvider</tt> with
748<tt>getLazyBitcodeModule</tt>, and pass their <tt>Module</tt> to
749functions that used to accept <tt>ModuleProvider</tt>. Clients who
750wrote their own <tt>ModuleProvider</tt>s will need to derive from
751<tt>GVMaterializer</tt> instead and use
752<tt>Module::setMaterializer</tt> to attach it to a
753<tt>Module</tt>.</li>
754
755<li><tt>GhostLinkage</tt> has given up the ghost.
756<tt>GlobalValue</tt>s that have not yet been read from their backing
757storage have the same linkage they will have after being read in.
758Clients must replace calls to
759<tt>GlobalValue::hasNotBeenReadFromBitcode</tt> with
760<tt>GlobalValue::isMaterializable</tt>.</li>
Daniel Dunbar61f41422010-02-10 04:09:52 +0000761
762<li>FIXME: Debug info has been totally redone. Add pointers to new APIs. Substantial caveats about compatibility of .ll and .bc files.</li>
763
Daniel Dunbar369889a2010-02-14 01:47:19 +0000764<li>The <tt>llvm/Support/DataTypes.h</tt> header has moved
765to <tt>llvm/System/DataTypes.h</tt>.</li>
766
Duncan Sandsdd29fc82010-02-17 17:20:17 +0000767<li>The <tt>isInteger</tt>, <tt>isIntOrIntVector</tt>, <tt>isFloatingPoint</tt>,
768<tt>isFPOrFPVector</tt> and <tt>isFPOrFPVector</tt> methods have been renamed
769<tt>isIntegerTy</tt>, <tt>isIntOrIntVectorTy</tt>, <tt>isFloatingPointTy</tt>,
770<tt>isFPOrFPVectorTy</tt> and <tt>isFPOrFPVectorTy</tt> respectively.</li>
Devang Patel0e3da1a2008-10-14 20:03:43 +0000771</ul>
Chris Lattner92eacf82008-10-13 17:57:36 +0000772
Chris Lattner92eacf82008-10-13 17:57:36 +0000773</div>
774
775
776
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000777<!-- *********************************************************************** -->
778<div class="doc_section">
779 <a name="portability">Portability and Supported Platforms</a>
780</div>
781<!-- *********************************************************************** -->
782
783<div class="doc_text">
784
785<p>LLVM is known to work on the following platforms:</p>
786
787<ul>
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000788<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000789 Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like
790 systems).</li>
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000791<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000792 and 64-bit modes.</li>
Chris Lattnere0798082008-02-06 18:00:06 +0000793<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000794<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
795 support is available for native builds with Visual C++).</li>
Chris Lattner9235ce52009-10-16 16:30:58 +0000796<li>Sun x86 and AMD64 machines running Solaris 10, OpenSolaris 0906.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000797<li>Alpha-based machines running Debian GNU/Linux.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000798</ul>
799
Chris Lattnerba948522008-06-05 06:57:39 +0000800<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000801to the machine and operating system on which it is built. However, minor
802porting may be required to get LLVM to work on new platforms. We welcome your
803portability patches and reports of successful builds or error messages.</p>
804
805</div>
806
807<!-- *********************************************************************** -->
808<div class="doc_section">
809 <a name="knownproblems">Known Problems</a>
810</div>
811<!-- *********************************************************************** -->
812
813<div class="doc_text">
814
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000815<p>This section contains significant known problems with the LLVM system,
Chris Lattnerb1ad47c2008-11-10 05:40:34 +0000816listed by component. If you run into a problem, please check the <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000817href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
818there isn't already one.</p>
819
Chris Lattner1f8dc512010-03-17 17:25:49 +0000820<ul>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000821<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
822using the stock GCC 3.x.x series 'out the box',
Chris Lattnerc09ffd22009-11-03 21:50:09 +0000823See: <a href="GettingStarted.html#brokengcc">Broken versions of GCC and other tools</a>.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000824However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
825for x86/x86-64 has been made available from the third party AuroraUX Project
826that has been meticulously tested for bootstrapping LLVM &amp; Clang.</li>
827</ul>
828
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000829</div>
830
831<!-- ======================================================================= -->
832<div class="doc_subsection">
833 <a name="experimental">Experimental features included with this release</a>
834</div>
835
836<div class="doc_text">
837
838<p>The following components of this LLVM release are either untested, known to
839be broken or unreliable, or are in early development. These components should
840not be relied on, and bugs should not be filed against them, but they may be
841useful to some people. In particular, if you would like to work on one of these
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000842components, please contact us on the <a
843href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000844
845<ul>
Wesley Peckbe6dc822010-03-18 14:31:30 +0000846<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
847 backends are experimental.</li>
Bill Wendling9c7c4382009-03-02 07:54:14 +0000848<li>The <tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000849 supported value for this option. The MachO writer is experimental, and
850 works much better in mainline SVN.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000851</ul>
852
853</div>
854
855<!-- ======================================================================= -->
856<div class="doc_subsection">
857 <a name="x86-be">Known problems with the X86 back-end</a>
858</div>
859
860<div class="doc_text">
861
862<ul>
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000863 <li>The X86 backend does not yet support
864 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
865 floating point stack</a>. It supports the 'f' and 't' constraints, but not
866 'u'.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000867 <li>The X86 backend generates inefficient floating point code when configured
868 to generate code for systems that don't have SSE2.</li>
Duncan Sands8b4f3772008-06-08 19:38:43 +0000869 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswellaea8c752009-03-02 15:28:15 +0000870 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
871 runtime currently due
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000872 to <a href="http://llvm.org/PR2255">several</a>
John Criswellaea8c752009-03-02 15:28:15 +0000873 <a href="http://llvm.org/PR2257">bugs</a> and due to lack of support for
874 the
875 'u' inline assembly constraint and for X87 floating point inline assembly.</li>
Dan Gohman3882ecb2008-06-08 23:05:11 +0000876 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner47202c32009-03-02 02:37:32 +0000877 <tt>va_arg</tt>. Currently, the llvm-gcc and front-ends support variadic
Dan Gohman3882ecb2008-06-08 23:05:11 +0000878 argument constructs on X86-64 by lowering them manually.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000879</ul>
880
881</div>
882
883<!-- ======================================================================= -->
884<div class="doc_subsection">
885 <a name="ppc-be">Known problems with the PowerPC back-end</a>
886</div>
887
888<div class="doc_text">
889
890<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000891<li>The Linux PPC32/ABI support needs testing for the interpreter and static
892compilation, and lacks support for debug information.</li>
893</ul>
894
895</div>
896
897<!-- ======================================================================= -->
898<div class="doc_subsection">
899 <a name="arm-be">Known problems with the ARM back-end</a>
900</div>
901
902<div class="doc_text">
903
904<ul>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000905<li>Support for the Advanced SIMD (Neon) instruction set is still incomplete
906and not well tested. Some features may not work at all, and the code quality
907may be poor in some cases.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000908<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000909processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000910results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswellaea8c752009-03-02 15:28:15 +0000911<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000912</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000913</ul>
914
915</div>
916
917<!-- ======================================================================= -->
918<div class="doc_subsection">
919 <a name="sparc-be">Known problems with the SPARC back-end</a>
920</div>
921
922<div class="doc_text">
923
924<ul>
John Criswellaea8c752009-03-02 15:28:15 +0000925<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000926 support the 64-bit SPARC ABI (-m64).</li>
927</ul>
928
929</div>
930
931<!-- ======================================================================= -->
932<div class="doc_subsection">
Bruno Cardoso Lopes62d45d72008-10-25 14:56:26 +0000933 <a name="mips-be">Known problems with the MIPS back-end</a>
934</div>
935
936<div class="doc_text">
937
938<ul>
Bruno Cardoso Lopes62d45d72008-10-25 14:56:26 +0000939<li>64-bit MIPS targets are not supported yet.</li>
940</ul>
941
942</div>
943
944<!-- ======================================================================= -->
945<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000946 <a name="alpha-be">Known problems with the Alpha back-end</a>
947</div>
948
949<div class="doc_text">
950
951<ul>
952
953<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
954appropriate nops inserted to ensure restartability.</li>
955
956</ul>
957</div>
958
959<!-- ======================================================================= -->
960<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000961 <a name="c-be">Known problems with the C back-end</a>
962</div>
963
964<div class="doc_text">
965
966<ul>
Chris Lattner499c07c2008-06-05 06:35:40 +0000967<li><a href="http://llvm.org/PR802">The C backend has only basic support for
968 inline assembly code</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000969<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
970 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greife33c5322009-03-02 12:02:51 +0000971 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandsbd0ad6e2008-02-10 13:40:55 +0000972<li>The C backend does not support all exception handling constructs.</li>
Duncan Sandse6e264c2009-02-25 11:51:54 +0000973<li>The C backend does not support arbitrary precision integers.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000974</ul>
975
976</div>
977
978
979<!-- ======================================================================= -->
980<div class="doc_subsection">
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000981 <a name="c-fe">Known problems with the llvm-gcc C and C++ front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000982</div>
983
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000984<div class="doc_text">
985
Chris Lattner499c07c2008-06-05 06:35:40 +0000986<p>The only major language feature of GCC not supported by llvm-gcc is
987 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
988 are only supported on some targets. For example, trampolines are only
Duncan Sandsa73561c2008-06-08 20:18:35 +0000989 supported on some targets (these are used when you take the address of a
990 nested function).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000991
Chris Lattner499c07c2008-06-05 06:35:40 +0000992<p>If you run into GCC extensions which are not supported, please let us know.
993</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000994
995</div>
996
997<!-- ======================================================================= -->
998<div class="doc_subsection">
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000999 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
1000</div>
1001
1002<div class="doc_text">
Gabor Greif1fc8fbc2008-11-04 21:50:59 +00001003<ul>
Chris Lattner6c8a1b82008-10-30 03:58:13 +00001004<li>Fortran support generally works, but there are still several unresolved bugs
Chris Lattner0b6ea7a2009-10-13 17:48:04 +00001005 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
1006 tools/gfortran component for details.</li>
Gabor Greif1fc8fbc2008-11-04 21:50:59 +00001007</ul>
Chris Lattner6c8a1b82008-10-30 03:58:13 +00001008</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001009
Chris Lattnerdaeb3232008-02-12 06:29:45 +00001010<!-- ======================================================================= -->
1011<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +00001012 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +00001013</div>
1014
1015<div class="doc_text">
John Criswellaea8c752009-03-02 15:28:15 +00001016The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
1017technology, and problems should be expected.
Chris Lattnerdaeb3232008-02-12 06:29:45 +00001018<ul>
Duncan Sandsa73561c2008-06-08 20:18:35 +00001019<li>The Ada front-end currently only builds on X86-32. This is mainly due
John Criswellaea8c752009-03-02 15:28:15 +00001020to lack of trampoline support (pointers to nested functions) on other platforms.
1021However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +00001022which does support trampolines.</li>
1023<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
Duncan Sandsf73473e2009-02-25 11:59:06 +00001024This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
1025exception handling, which is used internally by the compiler.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +00001026Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
Duncan Sands2dbc2e82008-10-13 17:27:23 +00001027<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
1028and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sandsf73473e2009-02-25 11:59:06 +00001029(c380004 also fails with gcc-4.2 mainline).
1030If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
1031causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sandsc2a29a02009-03-02 16:35:57 +00001032<li>Some GCC specific Ada tests continue to crash the compiler.</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +00001033<li>The <tt>-E</tt> binder option (exception backtraces)
Chris Lattnerdaeb3232008-02-12 06:29:45 +00001034<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
Chris Lattner0b6ea7a2009-10-13 17:48:04 +00001035crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +00001036<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
1037or finish at a non-byte offset</a> in a record. Workaround: do not pack records
1038or use representation clauses that result in a field of a non-discrete type
1039starting or finishing in the middle of a byte.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +00001040<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
1041'main' as generated by the Ada binder to be invalid</a>.
1042Workaround: hand edit the file to use pointers for <tt>argv</tt> and
1043<tt>envp</tt> rather than integers.</li>
1044<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
1045ignored</a>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +00001046</ul>
1047</div>
1048
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001049<!-- *********************************************************************** -->
1050<div class="doc_section">
1051 <a name="additionalinfo">Additional Information</a>
1052</div>
1053<!-- *********************************************************************** -->
1054
1055<div class="doc_text">
1056
1057<p>A wide variety of additional information is available on the <a
1058href="http://llvm.org">LLVM web page</a>, in particular in the <a
1059href="http://llvm.org/docs/">documentation</a> section. The web page also
1060contains versions of the API documentation which is up-to-date with the
1061Subversion version of the source code.
1062You can access versions of these documents specific to this release by going
1063into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
1064
1065<p>If you have any questions or comments about LLVM, please feel free to contact
1066us via the <a href="http://llvm.org/docs/#maillist"> mailing
1067lists</a>.</p>
1068
1069</div>
1070
1071<!-- *********************************************************************** -->
1072
1073<hr>
1074<address>
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