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7 <title>LLVM 2.6 Release Notes</title>
8</head>
9<body>
10
11<div class="doc_title">LLVM 2.6 Release Notes</div>
12
13<ol>
14 <li><a href="#intro">Introduction</a></li>
15 <li><a href="#subproj">Sub-project Status Update</a></li>
16 <li><a href="#externalproj">External Projects Using LLVM 2.6</a></li>
17 <li><a href="#whatsnew">What's New in LLVM 2.6?</a></li>
18 <li><a href="GettingStarted.html">Installation Instructions</a></li>
19 <li><a href="#portability">Portability and Supported Platforms</a></li>
20 <li><a href="#knownproblems">Known Problems</a></li>
21 <li><a href="#additionalinfo">Additional Information</a></li>
22</ol>
23
24<div class="doc_author">
25 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
26</div>
27
28<!-- *********************************************************************** -->
29<div class="doc_section">
30 <a name="intro">Introduction</a>
31</div>
32<!-- *********************************************************************** -->
33
34<div class="doc_text">
35
36<p>This document contains the release notes for the LLVM Compiler
37Infrastructure, release 2.6. Here we describe the status of LLVM, including
38major improvements from the previous release and significant known problems.
39All LLVM releases may be downloaded from the <a
40href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
41
42<p>For more information about LLVM, including information about the latest
43release, please check out the <a href="http://llvm.org/">main LLVM
44web site</a>. If you have questions or comments, the <a
45href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's Mailing
46List</a> is a good place to send them.</p>
47
48<p>Note that if you are reading this file from a Subversion checkout or the
49main LLVM web page, this document applies to the <i>next</i> release, not the
50current one. To see the release notes for a specific release, please see the
51<a href="http://llvm.org/releases/">releases page</a>.</p>
52
53</div>
54
55<!-- Unfinished features in 2.5:
56 Machine LICM
57 Machine Sinking
58 target-specific intrinsics
59 gold lto plugin
60 pre-alloc splitter, strong phi elim
61 <tt>llc -enable-value-prop</tt>, propagation of value info
62 (sign/zero ext info) from one MBB to another
63 debug info for optimized code
64 interpreter + libffi
65 postalloc scheduler: anti dependence breaking, hazard recognizer?
66
67initial support for debug line numbers when optimization enabled, not useful in
68 2.5 but will be for 2.6.
69
70 -->
71
72 <!-- for announcement email:
73 -->
74
75<!-- *********************************************************************** -->
76<div class="doc_section">
77 <a name="subproj">Sub-project Status Update</a>
78</div>
79<!-- *********************************************************************** -->
80
81<div class="doc_text">
82<p>
83The LLVM 2.6 distribution currently consists of code from the core LLVM
84repository &mdash;which roughly includes the LLVM optimizers, code generators
85and supporting tools &mdash; and the llvm-gcc repository. In addition to this
86code, the LLVM Project includes other sub-projects that are in development. The
87two which are the most actively developed are the <a href="#clang">Clang
88Project</a> and the <a href="#vmkit">VMKit Project</a>.
89</p>
90
91</div>
92
93
94<!--=========================================================================-->
95<div class="doc_subsection">
96<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
97</div>
98
99<div class="doc_text">
100
101<p>The <a href="http://clang.llvm.org/">Clang project</a> is an effort to build
102a set of new 'LLVM native' front-end technologies for the LLVM optimizer and
103code generator. While Clang is not included in the LLVM 2.6 release, it is
104continuing to make major strides forward in all areas. Its C and Objective-C
105parsing and code generation support is now very solid. For example, it is
106capable of successfully building many real-world applications for X86-32
107and X86-64,
108including the <a href="http://wiki.freebsd.org/BuildingFreeBSDWithClang">FreeBSD
109kernel</a> and <a href="http://gcc.gnu.org/gcc-4.2/">gcc 4.2</a>. C++ is also
110making <a href="http://clang.llvm.org/cxx_status.html">incredible progress</a>,
111and work on templates has recently started. If you are
112interested in fast compiles and good diagnostics, we encourage you to try it out
113by <a href="http://clang.llvm.org/get_started.html">building from mainline</a>
114and reporting any issues you hit to the <a
115href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">Clang front-end mailing
116list</a>.</p>
117
118<p>In the LLVM 2.6 time-frame, the Clang team has made many improvements:</p>
119
120<ul>
121<li>Something wonderful!</li>
Chris Lattnerc32a5322009-09-30 06:27:22 +0000[diff] [blame^]122<li>AuroraUX / FreeBSD &amp; OpenBSD Toolchain support.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]123<li>Many many bugs are fixed and many features have been added.</li>
124</ul>
125</div>
126
127<!--=========================================================================-->
128<div class="doc_subsection">
129<a name="clangsa">Clang Static Analyzer</a>
130</div>
131
132<div class="doc_text">
133
134<p>Previously announced in the 2.4 LLVM release, the Clang project also
135includes an early stage static source code analysis tool for <a
136href="http://clang.llvm.org/StaticAnalysis.html">automatically finding bugs</a>
137in C and Objective-C programs. The tool performs a growing set of checks to find
138bugs that occur on a specific path within a program.</p>
139
140<p>In the LLVM 2.6 time-frame there have been many significant improvements to
141XYZ.</p>
142
143<p>The set of checks performed by the static analyzer continues to expand, and
144future plans for the tool include full source-level inter-procedural analysis
145and deeper checks such as buffer overrun detection. There are many opportunities
146to extend and enhance the static analyzer, and anyone interested in working on
147this project is encouraged to get involved!</p>
148
149</div>
150
151<!--=========================================================================-->
152<div class="doc_subsection">
153<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
154</div>
155
156<div class="doc_text">
157<p>
158The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
159a JVM and a CLI Virtual Machines (Microsoft .NET is an
160implementation of the CLI) using the Just-In-Time compiler of LLVM.</p>
161
162<p>Following LLVM 2.6, VMKit has its XYZ release that you can find on its
163<a href="http://vmkit.llvm.org/releases/">webpage</a>. The release includes
164bug fixes, cleanup and new features. The major changes are:</p>
165
166<ul>
167
168<li>Something wonderful!</li>
169
170</ul>
171</div>
172
173<!-- *********************************************************************** -->
174<div class="doc_section">
175 <a name="externalproj">External Projects Using LLVM 2.6</a>
176</div>
177<!-- *********************************************************************** -->
178
Chris Lattnerc32a5322009-09-30 06:27:22 +0000[diff] [blame^]179
180<!--=========================================================================-->
181<div class="doc_subsection">
182<a name="macruby">MacRuby</a>
183</div>
184
185<div class="doc_text">
186
187<p>
188<a href="http://macruby.org">MacRuby</a> is an implementation of Ruby on top of
189core Mac OS X technologies, such as the Objective-C common runtime and garbage
190collector, and the CoreFoundation framework. It is principally developed by
191Apple and aims at enabling the creation of full-fledged Mac OS X applications.
192</p>
193
194<p>
195MacRuby uses LLVM for optimization passes, JIT and AOT compilation of Ruby
196expressions. It also uses zero-cost DWARF exceptions to implement Ruby exception
197handling.</p>
198
199</div>
200
201
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]202<!--=========================================================================-->
203<div class="doc_subsection">
204<a name="pure">Pure</a>
205</div>
206
207<div class="doc_text">
208<p>
209<a href="http://pure-lang.googlecode.com/">Pure</a>
210is an algebraic/functional programming language based on term rewriting.
211Programs are collections of equations which are used to evaluate expressions in
212a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
213lexical closures, a hygienic macro system (also based on term rewriting),
214built-in list and matrix support (including list and matrix comprehensions) and
215an easy-to-use C interface. The interpreter uses LLVM as a backend to
216 JIT-compile Pure programs to fast native code.</p>
217
218<p>In addition to the usual algebraic data structures, Pure also has
219MATLAB-style matrices in order to support numeric computations and signal
220processing in an efficient way. Pure is mainly aimed at mathematical
221applications right now, but it has been designed as a general purpose language.
222The dynamic interpreter environment and the C interface make it possible to use
223it as a kind of functional scripting language for many application areas.
224</p>
225</div>
226
227
228<!--=========================================================================-->
229<div class="doc_subsection">
230<a name="ldc">LLVM D Compiler</a>
231</div>
232
233<div class="doc_text">
234<p>
235<a href="http://www.dsource.org/projects/ldc">LDC</a> is an implementation of
236the D Programming Language using the LLVM optimizer and code generator.
237The LDC project works great with the LLVM 2.6 release. General improvements in
238this
239cycle have included new inline asm constraint handling, better debug info
240support, general bugfixes, and better x86-64 support. This has allowed
241some major improvements in LDC, getting us much closer to being as
242fully featured as the original DMD compiler from DigitalMars.
243</p>
244</div>
245
246<!--=========================================================================-->
247<div class="doc_subsection">
248<a name="RoadsendPHP">Roadsend PHP</a>
249</div>
250
251<div class="doc_text">
252<p><a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
253source implementation of the PHP programming
254language that uses LLVM for its optimizer, JIT, and static compiler. This is a
255reimplementation of an earlier project that is now based on LLVM.</p>
256</div>
257
Jeffrey Yasskinba2aa782009-06-24 21:09:13 +0000[diff] [blame]258<!--=========================================================================-->
259<div class="doc_subsection">
260<a name="Unladen Swallow">Unladen Swallow</a>
261</div>
262
263<div class="doc_text">
264<p><a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
265branch of <a href="http://python.org/">Python</a> intended to be fully
266compatible and significantly faster. It uses LLVM's optimization passes and JIT
267compiler.</p>
268</div>
269
Jeffrey Yasskin5e98cb72009-06-24 21:26:42 +0000[diff] [blame]270<!--=========================================================================-->
271<div class="doc_subsection">
272<a name="Rubinius">Rubinius</a>
273</div>
274
275<div class="doc_text">
276<p><a href="http://github.com/evanphx/rubinius">Rubinius</a> is a new virtual
277machine for Ruby. It leverages LLVM to dynamically compile Ruby code down to
278machine code using LLVM's JIT.</p>
279</div>
280
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]281
282<!-- *********************************************************************** -->
283<div class="doc_section">
284 <a name="whatsnew">What's New in LLVM 2.6?</a>
285</div>
286<!-- *********************************************************************** -->
287
288<div class="doc_text">
289
290<p>This release includes a huge number of bug fixes, performance tweaks, and
291minor improvements. Some of the major improvements and new features are listed
292in this section.
293</p>
294</div>
295
296<!--=========================================================================-->
297<div class="doc_subsection">
298<a name="majorfeatures">Major New Features</a>
299</div>
300
301<div class="doc_text">
302
303<p>LLVM 2.6 includes several major new capabilities:</p>
304
305<ul>
306<li>Something wonderful!</li>
Edward O'Callaghan50310f92009-08-22 02:17:22 +0000[diff] [blame]307<li>LLVM 2.6 includes a brand new experimental LLVM bindings to the Ada2005 programming language.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]308</ul>
309
310</div>
311
312
313<!--=========================================================================-->
314<div class="doc_subsection">
315<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
316</div>
317
318<div class="doc_text">
319
320<p>LLVM fully supports the llvm-gcc 4.2 front-end, which marries the GCC
321front-ends and driver with the LLVM optimizer and code generator. It currently
322includes support for the C, C++, Objective-C, Ada, and Fortran front-ends.</p>
323
324<ul>
325<li>Something wonderful!</li>
326</ul>
327
328</div>
329
330
331<!--=========================================================================-->
332<div class="doc_subsection">
333<a name="coreimprovements">LLVM IR and Core Improvements</a>
334</div>
335
336<div class="doc_text">
337<p>LLVM IR has several new features that are used by our existing front-ends and
338can be useful if you are writing a front-end for LLVM:</p>
339
340<ul>
341<li>Something wonderful!</li>
342</ul>
343
344</div>
345
346<!--=========================================================================-->
347<div class="doc_subsection">
348<a name="optimizer">Optimizer Improvements</a>
349</div>
350
351<div class="doc_text">
352
353<p>In addition to a large array of bug fixes and minor performance tweaks, this
354release includes a few major enhancements and additions to the optimizers:</p>
355
356<ul>
357
358<li>Something wonderful!</li>
359
360</ul>
361
362</div>
363
364<!--=========================================================================-->
365<div class="doc_subsection">
366<a name="codegen">Target Independent Code Generator Improvements</a>
367</div>
368
369<div class="doc_text">
370
371<p>We have put a significant amount of work into the code generator
372infrastructure, which allows us to implement more aggressive algorithms and make
373it run faster:</p>
374
375<ul>
376
377<li>Something wonderful!</li>
378</ul>
379</div>
380
381<!--=========================================================================-->
382<div class="doc_subsection">
383<a name="x86">X86-32 and X86-64 Target Improvements</a>
384</div>
385
386<div class="doc_text">
387<p>New features of the X86 target include:
388</p>
389
390<ul>
391
392<li>Something wonderful!</li>
393</ul>
394
395</div>
396
397<!--=========================================================================-->
398<div class="doc_subsection">
399<a name="pic16">PIC16 Target Improvements</a>
400</div>
401
402<div class="doc_text">
403<p>New features of the PIC16 target include:
404</p>
405
406<ul>
407<li>Something wonderful!</li>
408</ul>
409
410<p>Things not yet supported:</p>
411
412<ul>
413<li>Floating point.</li>
414<li>Passing/returning aggregate types to and from functions.</li>
415<li>Variable arguments.</li>
416<li>Indirect function calls.</li>
417<li>Interrupts/programs.</li>
418<li>Debug info.</li>
419</ul>
420
421</div>
422
Bob Wilson755cbe02009-08-12 21:19:49 +0000[diff] [blame]423<!--=========================================================================-->
424<div class="doc_subsection">
425<a name="ARM">ARM Target Improvements</a>
426</div>
427
428<div class="doc_text">
429<p>New features of the ARM target include:
430</p>
431
432<ul>
433
434<li>Preliminary support for processors, such as the Cortex-A8 and Cortex-A9,
Sandeep Patel64e39612009-08-20 15:01:16 +0000[diff] [blame]435that implement version v7-A of the ARM architecture. The ARM backend now
436supports both the Thumb2 and Advanced SIMD (Neon) instruction sets. The
437AAPCS-VFP "hard float" calling conventions are also supported with the
438<tt>-float-abi=hard</tt> flag. These features are still somewhat experimental
439and subject to change. The Neon intrinsics, in particular, may change in future
440releases of LLVM.
Bob Wilson755cbe02009-08-12 21:19:49 +0000[diff] [blame]441</li>
442</ul>
443
444</div>
445
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]446
447<!--=========================================================================-->
448<div class="doc_subsection">
449<a name="llvmc">Improvements in LLVMC</a>
450</div>
451
452<div class="doc_text">
453<p>New features include:</p>
454
455<ul>
456<li>Something wonderful!</li>
457</ul>
458
459</div>
460
461
462<!--=========================================================================-->
463<div class="doc_subsection">
464<a name="changes">Major Changes and Removed Features</a>
465</div>
466
467<div class="doc_text">
468
469<p>If you're already an LLVM user or developer with out-of-tree changes based
Owen Andersone27be3a2009-07-02 16:48:38 +0000[diff] [blame]470on LLVM 2.5, this section lists some "gotchas" that you may run into upgrading
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]471from the previous release.</p>
472
473<ul>
474
475<li>Something horrible!</li>
476
477</ul>
478
479
480<p>In addition, many APIs have changed in this release. Some of the major LLVM
481API changes are:</p>
482
483<ul>
Owen Andersone27be3a2009-07-02 16:48:38 +0000[diff] [blame]484<li>LLVM's global uniquing tables for <tt>Type</tt>s and <tt>Constant</tt>s have
485 been privatized into members of an <tt>LLVMContext</tt>. A number of APIs
486 now take an <tt>LLVMContext</tt> as a parameter. To smooth the transition
487 for clients that will only ever use a single context, the new
488 <tt>getGlobalContext()</tt> API can be used to access a default global
489 context which can be passed in any and all cases where a context is
490 required.
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]491<li>The <tt>getABITypeSize</tt> methods are now called <tt>getAllocSize</tt>.</li>
Dan Gohmanf667e7e2009-07-07 20:05:15 +0000[diff] [blame]492<li>The <tt>Add</tt>, <tt>Sub</tt>, and <tt>Mul</tt> operators are no longer
493 overloaded for floating-point types. Floating-point addition, subtraction,
494 and multiplication are now represented with new operators <tt>FAdd</tt>,
495 <tt>FSub</tt>, and <tt>FMul</tt>. In the <tt>IRBuilder</tt> API,
496 <tt>CreateAdd</tt>, <tt>CreateSub</tt>, <tt>CreateMul</tt>, and
497 <tt>CreateNeg</tt> should only be used for integer arithmetic now;
498 <tt>CreateFAdd</tt>, <tt>CreateFSub</tt>, <tt>CreateFMul</tt>, and
499 <tt>CreateFNeg</tt> should now be used for floating-point arithmetic.</li>
Daniel Dunbar02e73132009-07-12 20:41:27 +0000[diff] [blame]500<li>The DynamicLibrary class can no longer be constructed, its functionality has
501 moved to static member functions.</li>
Dan Gohmane4d54d72009-07-15 19:59:19 +0000[diff] [blame]502<li><tt>raw_fd_ostream</tt>'s constructor for opening a given filename now
503 takes an extra <tt>Force</tt> argument. If <tt>Force</tt> is set to
504 <tt>false</tt>, an error will be reported if a file with the given name
505 already exists. If <tt>Force</tt> is set to <tt>true</tt>, the file will
506 be silently truncated (which is the behavior before this flag was
507 added).</li>
Torok Edwinf6fa8ae2009-07-21 20:27:10 +0000[diff] [blame]508<li><tt>SCEVHandle</tt> no longer exists, because reference counting is no
509longer done for <tt>SCEV*</tt> objects, instead <tt>const SCEV*</tt> should be
510used.</li>
Daniel Dunbar8b5ee822009-07-25 05:26:53 +0000[diff] [blame]511
Daniel Dunbar6e0d1cb2009-07-25 04:41:11 +0000[diff] [blame]512<li>Many APIs, notably <tt>llvm::Value</tt>, now use the <tt>StringRef</tt>
513and <tt>Twine</tt> classes instead of passing <tt>const char*</tt>
514or <tt>std::string</tt>, as described in
515the <a href="ProgrammersManual.html#string_apis">Programmer's Manual</a>. Most
Daniel Dunbar8b5ee822009-07-25 05:26:53 +0000[diff] [blame]516clients should be unaffected by this transition, unless they are used to <tt>Value::getName()</tt> returning a string. Here are some tips on updating to 2.6:
517 <ul>
518 <li><tt>getNameStr()</tt> is still available, and matches the old
519 behavior. Replacing <tt>getName()</tt> calls with this is an safe option,
520 although more efficient alternatives are now possible.</li>
521
522 <li>If you were just relying on <tt>getName()</tt> being able to be sent to
523 a <tt>std::ostream</tt>, consider migrating
524 to <tt>llvm::raw_ostream</tt>.</li>
525
526 <li>If you were using <tt>getName().c_str()</tt> to get a <tt>const
527 char*</tt> pointer to the name, you can use <tt>getName().data()</tt>.
528 Note that this string (as before), may not be the entire name if the
529 name containts embedded null characters.</li>
530
531 <li>If you were using operator plus on the result of <tt>getName()</tt> and
532 treating the result as an <tt>std::string</tt>, you can either
533 uses <tt>Twine::str</tt> to get the result as an <tt>std::string</tt>, or
534 could move to a <tt>Twine</tt> based design.</li>
Daniel Dunbar03d76512009-07-25 23:55:21 +0000[diff] [blame]535
536 <li><tt>isName()</tt> should be replaced with comparison
Benjamin Kramere15192b2009-08-05 15:42:44 +0000[diff] [blame]537 against <tt>getName()</tt> (this is now efficient).
Daniel Dunbar8b5ee822009-07-25 05:26:53 +0000[diff] [blame]538 </ul>
539</li>
540
Daniel Dunbara5881e32009-07-26 02:12:58 +0000[diff] [blame]541<li>The registration interfaces for backend Targets has changed (what was
Daniel Dunbard6b06b12009-07-26 05:41:39 +0000[diff] [blame]542previously TargetMachineRegistry). For backend authors, see the <a href="WritingAnLLVMBackend.html#TargetRegistration">Writing An LLVM Backend</a> guide. For clients, the notable API changes are:
543 <ul>
544 <li><tt>TargetMachineRegistry</tt> has been renamed
545 to <tt>TargetRegistry</tt>.</li>
546
547 <li>Clients should move to using the <tt>TargetRegistry::lookupTarget()</tt>
548 function to find targets.</li>
549 </ul>
550</li>
Daniel Dunbar8b5ee822009-07-25 05:26:53 +0000[diff] [blame]551
Torok Edwinf6fa8ae2009-07-21 20:27:10 +0000[diff] [blame]552<li>llvm-dis now fails if output file exists, instead of dumping to stdout.
Daniel Dunbar6e0d1cb2009-07-25 04:41:11 +0000[diff] [blame]553FIXME: describe any other tool changes due to the raw_fd_ostream change. FIXME:
554This is not an API change, maybe there should be a tool changes section?</li>
Torok Edwinf6fa8ae2009-07-21 20:27:10 +0000[diff] [blame]555<li>temporarely due to Context API change passes should call doInitialization()
556method of the pass they inherit from, otherwise Context is NULL.
557FIXME: remove this entry when this is no longer needed.<li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]558</ul>
559
560</div>
561
562
563
564<!-- *********************************************************************** -->
565<div class="doc_section">
566 <a name="portability">Portability and Supported Platforms</a>
567</div>
568<!-- *********************************************************************** -->
569
570<div class="doc_text">
571
572<p>LLVM is known to work on the following platforms:</p>
573
574<ul>
575<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattner3e7b5ca2009-07-21 22:47:03 +0000[diff] [blame]576Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like systems).</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]577<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit
578and 64-bit modes.</li>
579<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
580<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
581 support is available for native builds with Visual C++).</li>
582<li>Sun UltraSPARC workstations running Solaris 10.</li>
583<li>Alpha-based machines running Debian GNU/Linux.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]584</ul>
585
586<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
587to the machine and operating system on which it is built. However, minor
588porting may be required to get LLVM to work on new platforms. We welcome your
589portability patches and reports of successful builds or error messages.</p>
590
591</div>
592
593<!-- *********************************************************************** -->
594<div class="doc_section">
595 <a name="knownproblems">Known Problems</a>
596</div>
597<!-- *********************************************************************** -->
598
599<div class="doc_text">
600
601<p>This section contains significant known problems with the LLVM system,
602listed by component. If you run into a problem, please check the <a
603href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
604there isn't already one.</p>
605
Chris Lattner3e7b5ca2009-07-21 22:47:03 +0000[diff] [blame]606<ul>
Chris Lattneraedb59a2009-07-21 23:17:26 +0000[diff] [blame]607<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
Chris Lattner3e7b5ca2009-07-21 22:47:03 +0000[diff] [blame]608using the stock GCC 3.x.x series 'out the box',
609See: <a href="#brokengcc">Broken versions of GCC and other tools</a>.
610However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
611for x86/x64 has been made available from the third party AuroraUX Project
612that has been meticulously tested for bootstrapping LLVM & Clang.</li>
613</ul>
614
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]615</div>
616
617<!-- ======================================================================= -->
618<div class="doc_subsection">
619 <a name="experimental">Experimental features included with this release</a>
620</div>
621
622<div class="doc_text">
623
624<p>The following components of this LLVM release are either untested, known to
625be broken or unreliable, or are in early development. These components should
626not be relied on, and bugs should not be filed against them, but they may be
627useful to some people. In particular, if you would like to work on one of these
628components, please contact us on the <a
629href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
630
631<ul>
Dan Gohmand2cb3d22009-07-24 00:30:09 +0000[diff] [blame]632<li>The MSIL, Alpha, SPU, MIPS, and PIC16 backends are experimental.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]633<li>The <tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
634 supported value for this option.</li>
635</ul>
636
637</div>
638
639<!-- ======================================================================= -->
640<div class="doc_subsection">
641 <a name="x86-be">Known problems with the X86 back-end</a>
642</div>
643
644<div class="doc_text">
645
646<ul>
647 <li>The X86 backend does not yet support
648 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
649 floating point stack</a>. It supports the 'f' and 't' constraints, but not
650 'u'.</li>
651 <li>The X86 backend generates inefficient floating point code when configured
652 to generate code for systems that don't have SSE2.</li>
653 <li>Win64 code generation wasn't widely tested. Everything should work, but we
654 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
655 runtime currently due
656 to <a href="http://llvm.org/PR2255">several</a>
657 <a href="http://llvm.org/PR2257">bugs</a> and due to lack of support for
658 the
659 'u' inline assembly constraint and for X87 floating point inline assembly.</li>
660 <li>The X86-64 backend does not yet support the LLVM IR instruction
661 <tt>va_arg</tt>. Currently, the llvm-gcc and front-ends support variadic
662 argument constructs on X86-64 by lowering them manually.</li>
663</ul>
664
665</div>
666
667<!-- ======================================================================= -->
668<div class="doc_subsection">
669 <a name="ppc-be">Known problems with the PowerPC back-end</a>
670</div>
671
672<div class="doc_text">
673
674<ul>
675<li>The Linux PPC32/ABI support needs testing for the interpreter and static
676compilation, and lacks support for debug information.</li>
677</ul>
678
679</div>
680
681<!-- ======================================================================= -->
682<div class="doc_subsection">
683 <a name="arm-be">Known problems with the ARM back-end</a>
684</div>
685
686<div class="doc_text">
687
688<ul>
Bob Wilson755cbe02009-08-12 21:19:49 +0000[diff] [blame]689<li>Support for the Advanced SIMD (Neon) instruction set is still incomplete
690and not well tested. Some features may not work at all, and the code quality
691may be poor in some cases.</li>
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]692<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
693processors, thumb programs can crash or produce wrong
694results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
695<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
696</li>
697<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly
698 execute
699programs compiled with LLVM. Please use more recent versions of QEMU.</li>
700</ul>
701
702</div>
703
704<!-- ======================================================================= -->
705<div class="doc_subsection">
706 <a name="sparc-be">Known problems with the SPARC back-end</a>
707</div>
708
709<div class="doc_text">
710
711<ul>
712<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
713 support the 64-bit SPARC ABI (-m64).</li>
714</ul>
715
716</div>
717
718<!-- ======================================================================= -->
719<div class="doc_subsection">
720 <a name="mips-be">Known problems with the MIPS back-end</a>
721</div>
722
723<div class="doc_text">
724
725<ul>
726<li>The O32 ABI is not fully supported.</li>
727<li>64-bit MIPS targets are not supported yet.</li>
728</ul>
729
730</div>
731
732<!-- ======================================================================= -->
733<div class="doc_subsection">
734 <a name="alpha-be">Known problems with the Alpha back-end</a>
735</div>
736
737<div class="doc_text">
738
739<ul>
740
741<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
742appropriate nops inserted to ensure restartability.</li>
743
744</ul>
745</div>
746
747<!-- ======================================================================= -->
748<div class="doc_subsection">
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]749 <a name="c-be">Known problems with the C back-end</a>
750</div>
751
752<div class="doc_text">
753
754<ul>
755<li><a href="http://llvm.org/PR802">The C backend has only basic support for
756 inline assembly code</a>.</li>
757<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
758 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
759 C++ code compiled with <tt>llc</tt> or native compilers.</li>
760<li>The C backend does not support all exception handling constructs.</li>
761<li>The C backend does not support arbitrary precision integers.</li>
762</ul>
763
764</div>
765
766
767<!-- ======================================================================= -->
768<div class="doc_subsection">
769 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
770</div>
771
772<div class="doc_text">
773
774<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
775Optimization</a> on most platforms "out-of-the-box". Please inquire on the
776LLVMdev mailing list if you are interested.</p>
777
778<p>The only major language feature of GCC not supported by llvm-gcc is
779 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
780 are only supported on some targets. For example, trampolines are only
781 supported on some targets (these are used when you take the address of a
782 nested function).</p>
783
784<p>If you run into GCC extensions which are not supported, please let us know.
785</p>
786
787</div>
788
789<!-- ======================================================================= -->
790<div class="doc_subsection">
791 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
792</div>
793
794<div class="doc_text">
795
796<p>The C++ front-end is considered to be fully
797tested and works for a number of non-trivial programs, including LLVM
798itself, Qt, Mozilla, etc.</p>
799
800<ul>
801<li>Exception handling works well on the X86 and PowerPC targets. Currently
802 only Linux and Darwin targets are supported (both 32 and 64 bit).</li>
803</ul>
804
805</div>
806
807<!-- ======================================================================= -->
808<div class="doc_subsection">
809 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
810</div>
811
812<div class="doc_text">
813<ul>
814<li>Fortran support generally works, but there are still several unresolved bugs
815 in Bugzilla. Please see the tools/gfortran component for details.</li>
816</ul>
817</div>
818
819<!-- ======================================================================= -->
820<div class="doc_subsection">
821 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
822</div>
823
824<div class="doc_text">
825The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
826technology, and problems should be expected.
827<ul>
828<li>The Ada front-end currently only builds on X86-32. This is mainly due
829to lack of trampoline support (pointers to nested functions) on other platforms.
830However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
831which does support trampolines.</li>
832<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
833This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
834exception handling, which is used internally by the compiler.
835Workaround: configure with --disable-bootstrap.</li>
836<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
837and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
838(c380004 also fails with gcc-4.2 mainline).
839If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
840causes the compiler to go into an infinite loop, using up all system memory.</li>
841<li>Some GCC specific Ada tests continue to crash the compiler.</li>
842<li>The -E binder option (exception backtraces)
843<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
844crashing if an exception is raised. Workaround: do not use -E.</li>
845<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
846or finish at a non-byte offset</a> in a record. Workaround: do not pack records
847or use representation clauses that result in a field of a non-discrete type
848starting or finishing in the middle of a byte.</li>
849<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
850'main' as generated by the Ada binder to be invalid</a>.
851Workaround: hand edit the file to use pointers for <tt>argv</tt> and
852<tt>envp</tt> rather than integers.</li>
853<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
854ignored</a>.</li>
855</ul>
856</div>
857
Erick Tryzelaar17167be2009-09-28 04:42:55 +0000[diff] [blame]858<!-- ======================================================================= -->
859<div class="doc_subsection">
860 <a name="ocaml-bindingse">Known problems with the O'Caml bindings</a>
861</div>
862
863<div class="doc_text">
864
865<p>The Llvm.Linkage module is broken, and has incorrect values. Only
866Llvm.Linkage.External, Llvm.Linkage.Available_externally, and
867Llvm.Linkage.Link_once will be correct. If you need any of the other linkage
868modes, you'll have to write an external C library in order to expose the
869functionality. This has been fixed in the trunk.</p>
870</div>
871
Duncan Sandse2e4a892009-06-24 08:38:48 +0000[diff] [blame]872<!-- *********************************************************************** -->
873<div class="doc_section">
874 <a name="additionalinfo">Additional Information</a>
875</div>
876<!-- *********************************************************************** -->
877
878<div class="doc_text">
879
880<p>A wide variety of additional information is available on the <a
881href="http://llvm.org">LLVM web page</a>, in particular in the <a
882href="http://llvm.org/docs/">documentation</a> section. The web page also
883contains versions of the API documentation which is up-to-date with the
884Subversion version of the source code.
885You can access versions of these documents specific to this release by going
886into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
887
888<p>If you have any questions or comments about LLVM, please feel free to contact
889us via the <a href="http://llvm.org/docs/#maillist"> mailing
890lists</a>.</p>
891
892</div>
893
894<!-- *********************************************************************** -->
895
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