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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 Lattner58b1d0f2010-03-17 04:41:49 +0000477
Chris Lattner2b656342010-03-17 06:41:58 +0000478CondProp pass removed (functionality merged into jump threading).
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000479AndersAA got removed (from 2.7 or mainline?)
Chris Lattner2b656342010-03-17 06:41:58 +0000480PredSimplify, LoopVR, GVNPRE got removed.
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000481LLVM command line tools now overwrite their output, before they would only do this with -f.
482DOUT removed, use DEBUG(errs() instead.
483Much stuff converted to use raw_ostream instead of std::ostream.
484TargetAsmInfo renamed to MCAsmInfo
485llvm/ADT/iterator.h gone.
486
Chris Lattner2b656342010-03-17 06:41:58 +0000487
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000488</div>
489
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000490<!--=========================================================================-->
491<div class="doc_subsection">
Chris Lattner47202c32009-03-02 02:37:32 +0000492<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerc3649452008-02-10 08:17:19 +0000493</div>
494
495<div class="doc_text">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000496<p>LLVM IR has several new features for better support of new targets and that
497expose new optimization opportunities:</p>
Chris Lattnerc3649452008-02-10 08:17:19 +0000498
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000499<ul>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000500<li>...</li>
Chris Lattnerc3649452008-02-10 08:17:19 +0000501</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000502
Chris Lattnerc3649452008-02-10 08:17:19 +0000503</div>
504
505<!--=========================================================================-->
506<div class="doc_subsection">
Chris Lattner8fda4952008-02-10 07:46:44 +0000507<a name="optimizer">Optimizer Improvements</a>
508</div>
509
510<div class="doc_text">
511
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000512<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattnerea9c2242008-10-13 21:50:36 +0000513release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner8fda4952008-02-10 07:46:44 +0000514
515<ul>
516
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000517<li>...</li>
Chris Lattner47202c32009-03-02 02:37:32 +0000518
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000519</ul>
Chris Lattner47202c32009-03-02 02:37:32 +0000520
Chris Lattner317685c2010-03-01 19:29:17 +0000521<p>Also, -anders-aa was removed</p>
522
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000523</div>
Chris Lattner47202c32009-03-02 02:37:32 +0000524
Chris Lattner47202c32009-03-02 02:37:32 +0000525
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000526<!--=========================================================================-->
527<div class="doc_subsection">
528<a name="executionengine">Interpreter and JIT Improvements</a>
529</div>
Chris Lattnerea9c2242008-10-13 21:50:36 +0000530
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000531<div class="doc_text">
532
533<ul>
Jeffrey Yasskin40715142010-01-29 19:10:38 +0000534<li>The JIT now <a
535href="http://llvm.org/viewvc/llvm-project?view=rev&revision=85295">defaults
536to compiling eagerly</a> to avoid a race condition in the lazy JIT.
537Clients that still want the lazy JIT can switch it on by calling
538<tt>ExecutionEngine::DisableLazyCompilation(false)</tt>.</li>
Jeffrey Yasskinc0577082010-02-11 01:07:39 +0000539<li>It is now possible to create more than one JIT instance in the same process.
540These JITs can generate machine code in parallel,
541although <a href="http://llvm.org/docs/ProgrammersManual.html#jitthreading">you
542still have to obey the other threading restrictions</a>.</li>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000543</ul>
544
545</div>
546
547<!--=========================================================================-->
548<div class="doc_subsection">
Chris Lattner5f393542009-03-02 03:24:11 +0000549<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000550</div>
551
552<div class="doc_text">
553
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000554<p>We have put a significant amount of work into the code generator
555infrastructure, which allows us to implement more aggressive algorithms and make
556it run faster:</p>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000557
558<ul>
Chris Lattner5f393542009-03-02 03:24:11 +0000559
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000560<li>...</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000561</ul>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000562</div>
563
Chris Lattner47202c32009-03-02 02:37:32 +0000564<!--=========================================================================-->
565<div class="doc_subsection">
566<a name="x86">X86-32 and X86-64 Target Improvements</a>
567</div>
568
569<div class="doc_text">
570<p>New features of the X86 target include:
571</p>
572
573<ul>
Chris Lattner5f393542009-03-02 03:24:11 +0000574
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000575<li>...</li>
Chris Lattner5f393542009-03-02 03:24:11 +0000576
Chris Lattner47202c32009-03-02 02:37:32 +0000577</ul>
578
Chris Lattner47202c32009-03-02 02:37:32 +0000579</div>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000580
581<!--=========================================================================-->
582<div class="doc_subsection">
Chris Lattnere1fbd752009-02-26 07:32:11 +0000583<a name="pic16">PIC16 Target Improvements</a>
584</div>
585
586<div class="doc_text">
587<p>New features of the PIC16 target include:
588</p>
589
590<ul>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000591<li>...</li>
Chris Lattnere1fbd752009-02-26 07:32:11 +0000592</ul>
593
594<p>Things not yet supported:</p>
595
596<ul>
Chris Lattnere1fbd752009-02-26 07:32:11 +0000597<li>Variable arguments.</li>
Chris Lattner5f393542009-03-02 03:24:11 +0000598<li>Interrupts/programs.</li>
Chris Lattnere1fbd752009-02-26 07:32:11 +0000599</ul>
600
601</div>
602
Chris Lattnere1fbd752009-02-26 07:32:11 +0000603<!--=========================================================================-->
604<div class="doc_subsection">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000605<a name="ARM">ARM Target Improvements</a>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000606</div>
607
608<div class="doc_text">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000609<p>New features of the ARM target include:
610</p>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000611
612<ul>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000613
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000614<li>...</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000615</ul>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000616
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000617
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000618</div>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000619
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000620<!--=========================================================================-->
621<div class="doc_subsection">
622<a name="OtherTarget">Other Target Specific Improvements</a>
623</div>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000624
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000625<div class="doc_text">
626<p>New features of other targets include:
627</p>
628
629<ul>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000630<li>...</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000631</ul>
632
633</div>
634
635<!--=========================================================================-->
636<div class="doc_subsection">
637<a name="newapis">New Useful APIs</a>
638</div>
639
640<div class="doc_text">
641
642<p>This release includes a number of new APIs that are used internally, which
643 may also be useful for external clients.
644</p>
645
646<ul>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000647<li>...</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000648</ul>
649
650
651</div>
652
653<!--=========================================================================-->
654<div class="doc_subsection">
655<a name="otherimprovements">Other Improvements and New Features</a>
656</div>
657
658<div class="doc_text">
659<p>Other miscellaneous features include:</p>
660
661<ul>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000662<li>...</li>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000663</ul>
664
665</div>
666
Chris Lattnere45f18b2008-06-05 08:02:49 +0000667
668<!--=========================================================================-->
669<div class="doc_subsection">
Chris Lattner92eacf82008-10-13 17:57:36 +0000670<a name="changes">Major Changes and Removed Features</a>
671</div>
672
673<div class="doc_text">
674
Chris Lattnercc64a322008-10-13 22:06:31 +0000675<p>If you're already an LLVM user or developer with out-of-tree changes based
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000676on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading
Chris Lattnercc64a322008-10-13 22:06:31 +0000677from the previous release.</p>
Chris Lattner92eacf82008-10-13 17:57:36 +0000678
679<ul>
Jeffrey Yasskin260af332010-02-09 23:03:44 +0000680<li>The LLVM interpreter now defaults to <em>not</em> using <tt>libffi</tt> even
681if you have it installed. This makes it more likely that an LLVM built on one
682system will work when copied to a similar system. To use <tt>libffi</tt>,
683configure with <tt>--enable-libffi</tt>.
684</li>
Chris Lattnercc64a322008-10-13 22:06:31 +0000685</ul>
686
687
688<p>In addition, many APIs have changed in this release. Some of the major LLVM
689API changes are:</p>
690
691<ul>
Jeffrey Yasskin2ca16212010-01-28 01:41:20 +0000692<li><tt>ModuleProvider</tt> has been <a
693href="http://llvm.org/viewvc/llvm-project?view=rev&revision=94686">removed</a>
694and its methods moved to <tt>Module</tt> and <tt>GlobalValue</tt>.
695Most clients can remove uses of <tt>ExistingModuleProvider</tt>,
696replace <tt>getBitcodeModuleProvider</tt> with
697<tt>getLazyBitcodeModule</tt>, and pass their <tt>Module</tt> to
698functions that used to accept <tt>ModuleProvider</tt>. Clients who
699wrote their own <tt>ModuleProvider</tt>s will need to derive from
700<tt>GVMaterializer</tt> instead and use
701<tt>Module::setMaterializer</tt> to attach it to a
702<tt>Module</tt>.</li>
703
704<li><tt>GhostLinkage</tt> has given up the ghost.
705<tt>GlobalValue</tt>s that have not yet been read from their backing
706storage have the same linkage they will have after being read in.
707Clients must replace calls to
708<tt>GlobalValue::hasNotBeenReadFromBitcode</tt> with
709<tt>GlobalValue::isMaterializable</tt>.</li>
Daniel Dunbar61f41422010-02-10 04:09:52 +0000710
711<li>FIXME: Debug info has been totally redone. Add pointers to new APIs. Substantial caveats about compatibility of .ll and .bc files.</li>
712
Daniel Dunbar369889a2010-02-14 01:47:19 +0000713<li>The <tt>llvm/Support/DataTypes.h</tt> header has moved
714to <tt>llvm/System/DataTypes.h</tt>.</li>
715
Duncan Sandsdd29fc82010-02-17 17:20:17 +0000716<li>The <tt>isInteger</tt>, <tt>isIntOrIntVector</tt>, <tt>isFloatingPoint</tt>,
717<tt>isFPOrFPVector</tt> and <tt>isFPOrFPVector</tt> methods have been renamed
718<tt>isIntegerTy</tt>, <tt>isIntOrIntVectorTy</tt>, <tt>isFloatingPointTy</tt>,
719<tt>isFPOrFPVectorTy</tt> and <tt>isFPOrFPVectorTy</tt> respectively.</li>
Devang Patel0e3da1a2008-10-14 20:03:43 +0000720</ul>
Chris Lattner92eacf82008-10-13 17:57:36 +0000721
Chris Lattner92eacf82008-10-13 17:57:36 +0000722</div>
723
724
725
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000726<!-- *********************************************************************** -->
727<div class="doc_section">
728 <a name="portability">Portability and Supported Platforms</a>
729</div>
730<!-- *********************************************************************** -->
731
732<div class="doc_text">
733
734<p>LLVM is known to work on the following platforms:</p>
735
736<ul>
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000737<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000738 Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like
739 systems).</li>
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000740<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000741 and 64-bit modes.</li>
Chris Lattnere0798082008-02-06 18:00:06 +0000742<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000743<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
744 support is available for native builds with Visual C++).</li>
Chris Lattner9235ce52009-10-16 16:30:58 +0000745<li>Sun x86 and AMD64 machines running Solaris 10, OpenSolaris 0906.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000746<li>Alpha-based machines running Debian GNU/Linux.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000747</ul>
748
Chris Lattnerba948522008-06-05 06:57:39 +0000749<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000750to the machine and operating system on which it is built. However, minor
751porting may be required to get LLVM to work on new platforms. We welcome your
752portability patches and reports of successful builds or error messages.</p>
753
754</div>
755
756<!-- *********************************************************************** -->
757<div class="doc_section">
758 <a name="knownproblems">Known Problems</a>
759</div>
760<!-- *********************************************************************** -->
761
762<div class="doc_text">
763
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000764<p>This section contains significant known problems with the LLVM system,
Chris Lattnerb1ad47c2008-11-10 05:40:34 +0000765listed by component. If you run into a problem, please check the <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000766href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
767there isn't already one.</p>
768
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000769<ul>
770<li>The llvm-gcc bootstrap will fail with some versions of binutils (e.g. 2.15)
771 with a message of "<tt><a href="http://llvm.org/PR5004">Error: can not do 8
772 byte pc-relative relocation</a></tt>" when building C++ code. We intend to
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000773 fix this on mainline, but a workaround is to upgrade to binutils 2.17 or
774 later.</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000775
776<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
777using the stock GCC 3.x.x series 'out the box',
Chris Lattnerc09ffd22009-11-03 21:50:09 +0000778See: <a href="GettingStarted.html#brokengcc">Broken versions of GCC and other tools</a>.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000779However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
780for x86/x86-64 has been made available from the third party AuroraUX Project
781that has been meticulously tested for bootstrapping LLVM &amp; Clang.</li>
782</ul>
783
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000784</div>
785
786<!-- ======================================================================= -->
787<div class="doc_subsection">
788 <a name="experimental">Experimental features included with this release</a>
789</div>
790
791<div class="doc_text">
792
793<p>The following components of this LLVM release are either untested, known to
794be broken or unreliable, or are in early development. These components should
795not be relied on, and bugs should not be filed against them, but they may be
796useful to some people. In particular, if you would like to work on one of these
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000797components, please contact us on the <a
798href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000799
800<ul>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000801<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430 and SystemZ backends are
802 experimental.</li>
Bill Wendling9c7c4382009-03-02 07:54:14 +0000803<li>The <tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000804 supported value for this option. The MachO writer is experimental, and
805 works much better in mainline SVN.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000806</ul>
807
808</div>
809
810<!-- ======================================================================= -->
811<div class="doc_subsection">
812 <a name="x86-be">Known problems with the X86 back-end</a>
813</div>
814
815<div class="doc_text">
816
817<ul>
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000818 <li>The X86 backend does not yet support
819 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
820 floating point stack</a>. It supports the 'f' and 't' constraints, but not
821 'u'.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000822 <li>The X86 backend generates inefficient floating point code when configured
823 to generate code for systems that don't have SSE2.</li>
Duncan Sands8b4f3772008-06-08 19:38:43 +0000824 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswellaea8c752009-03-02 15:28:15 +0000825 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
826 runtime currently due
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000827 to <a href="http://llvm.org/PR2255">several</a>
John Criswellaea8c752009-03-02 15:28:15 +0000828 <a href="http://llvm.org/PR2257">bugs</a> and due to lack of support for
829 the
830 'u' inline assembly constraint and for X87 floating point inline assembly.</li>
Dan Gohman3882ecb2008-06-08 23:05:11 +0000831 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner47202c32009-03-02 02:37:32 +0000832 <tt>va_arg</tt>. Currently, the llvm-gcc and front-ends support variadic
Dan Gohman3882ecb2008-06-08 23:05:11 +0000833 argument constructs on X86-64 by lowering them manually.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000834</ul>
835
836</div>
837
838<!-- ======================================================================= -->
839<div class="doc_subsection">
840 <a name="ppc-be">Known problems with the PowerPC back-end</a>
841</div>
842
843<div class="doc_text">
844
845<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000846<li>The Linux PPC32/ABI support needs testing for the interpreter and static
847compilation, and lacks support for debug information.</li>
848</ul>
849
850</div>
851
852<!-- ======================================================================= -->
853<div class="doc_subsection">
854 <a name="arm-be">Known problems with the ARM back-end</a>
855</div>
856
857<div class="doc_text">
858
859<ul>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000860<li>Support for the Advanced SIMD (Neon) instruction set is still incomplete
861and not well tested. Some features may not work at all, and the code quality
862may be poor in some cases.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000863<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000864processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000865results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswellaea8c752009-03-02 15:28:15 +0000866<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000867</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000868</ul>
869
870</div>
871
872<!-- ======================================================================= -->
873<div class="doc_subsection">
874 <a name="sparc-be">Known problems with the SPARC back-end</a>
875</div>
876
877<div class="doc_text">
878
879<ul>
John Criswellaea8c752009-03-02 15:28:15 +0000880<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000881 support the 64-bit SPARC ABI (-m64).</li>
882</ul>
883
884</div>
885
886<!-- ======================================================================= -->
887<div class="doc_subsection">
Bruno Cardoso Lopes62d45d72008-10-25 14:56:26 +0000888 <a name="mips-be">Known problems with the MIPS back-end</a>
889</div>
890
891<div class="doc_text">
892
893<ul>
Bruno Cardoso Lopes62d45d72008-10-25 14:56:26 +0000894<li>64-bit MIPS targets are not supported yet.</li>
895</ul>
896
897</div>
898
899<!-- ======================================================================= -->
900<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000901 <a name="alpha-be">Known problems with the Alpha back-end</a>
902</div>
903
904<div class="doc_text">
905
906<ul>
907
908<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
909appropriate nops inserted to ensure restartability.</li>
910
911</ul>
912</div>
913
914<!-- ======================================================================= -->
915<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000916 <a name="c-be">Known problems with the C back-end</a>
917</div>
918
919<div class="doc_text">
920
921<ul>
Chris Lattner499c07c2008-06-05 06:35:40 +0000922<li><a href="http://llvm.org/PR802">The C backend has only basic support for
923 inline assembly code</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000924<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
925 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greife33c5322009-03-02 12:02:51 +0000926 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandsbd0ad6e2008-02-10 13:40:55 +0000927<li>The C backend does not support all exception handling constructs.</li>
Duncan Sandse6e264c2009-02-25 11:51:54 +0000928<li>The C backend does not support arbitrary precision integers.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000929</ul>
930
931</div>
932
933
934<!-- ======================================================================= -->
935<div class="doc_subsection">
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000936 <a name="c-fe">Known problems with the llvm-gcc C and C++ front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000937</div>
938
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000939<div class="doc_text">
940
Chris Lattner499c07c2008-06-05 06:35:40 +0000941<p>The only major language feature of GCC not supported by llvm-gcc is
942 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
943 are only supported on some targets. For example, trampolines are only
Duncan Sandsa73561c2008-06-08 20:18:35 +0000944 supported on some targets (these are used when you take the address of a
945 nested function).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000946
Chris Lattner499c07c2008-06-05 06:35:40 +0000947<p>If you run into GCC extensions which are not supported, please let us know.
948</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000949
950</div>
951
952<!-- ======================================================================= -->
953<div class="doc_subsection">
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000954 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
955</div>
956
957<div class="doc_text">
Gabor Greif1fc8fbc2008-11-04 21:50:59 +0000958<ul>
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000959<li>Fortran support generally works, but there are still several unresolved bugs
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000960 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
961 tools/gfortran component for details.</li>
Gabor Greif1fc8fbc2008-11-04 21:50:59 +0000962</ul>
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000963</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000964
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000965<!-- ======================================================================= -->
966<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000967 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000968</div>
969
970<div class="doc_text">
John Criswellaea8c752009-03-02 15:28:15 +0000971The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
972technology, and problems should be expected.
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000973<ul>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000974<li>The Ada front-end currently only builds on X86-32. This is mainly due
John Criswellaea8c752009-03-02 15:28:15 +0000975to lack of trampoline support (pointers to nested functions) on other platforms.
976However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000977which does support trampolines.</li>
978<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
Duncan Sandsf73473e2009-02-25 11:59:06 +0000979This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
980exception handling, which is used internally by the compiler.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000981Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
Duncan Sands2dbc2e82008-10-13 17:27:23 +0000982<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
983and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sandsf73473e2009-02-25 11:59:06 +0000984(c380004 also fails with gcc-4.2 mainline).
985If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
986causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sandsc2a29a02009-03-02 16:35:57 +0000987<li>Some GCC specific Ada tests continue to crash the compiler.</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000988<li>The <tt>-E</tt> binder option (exception backtraces)
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000989<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000990crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000991<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
992or finish at a non-byte offset</a> in a record. Workaround: do not pack records
993or use representation clauses that result in a field of a non-discrete type
994starting or finishing in the middle of a byte.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000995<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
996'main' as generated by the Ada binder to be invalid</a>.
997Workaround: hand edit the file to use pointers for <tt>argv</tt> and
998<tt>envp</tt> rather than integers.</li>
999<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
1000ignored</a>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +00001001</ul>
1002</div>
1003
Chris Lattner0b6ea7a2009-10-13 17:48:04 +00001004<!-- ======================================================================= -->
1005<div class="doc_subsection">
1006 <a name="ocaml-bindings">Known problems with the O'Caml bindings</a>
1007</div>
1008
1009<div class="doc_text">
1010
1011<p>The <tt>Llvm.Linkage</tt> module is broken, and has incorrect values. Only
1012<tt>Llvm.Linkage.External</tt>, <tt>Llvm.Linkage.Available_externally</tt>, and
1013<tt>Llvm.Linkage.Link_once</tt> will be correct. If you need any of the other linkage
1014modes, you'll have to write an external C library in order to expose the
1015functionality. This has been fixed in the trunk.</p>
1016</div>
1017
Dan Gohmanf17a25c2007-07-18 16:29:46 +00001018<!-- *********************************************************************** -->
1019<div class="doc_section">
1020 <a name="additionalinfo">Additional Information</a>
1021</div>
1022<!-- *********************************************************************** -->
1023
1024<div class="doc_text">
1025
1026<p>A wide variety of additional information is available on the <a
1027href="http://llvm.org">LLVM web page</a>, in particular in the <a
1028href="http://llvm.org/docs/">documentation</a> section. The web page also
1029contains versions of the API documentation which is up-to-date with the
1030Subversion version of the source code.
1031You can access versions of these documents specific to this release by going
1032into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
1033
1034<p>If you have any questions or comments about LLVM, please feel free to contact
1035us via the <a href="http://llvm.org/docs/#maillist"> mailing
1036lists</a>.</p>
1037
1038</div>
1039
1040<!-- *********************************************************************** -->
1041
1042<hr>
1043<address>
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1049 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
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