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Dan Gohmanb44f6c62010-05-03 23:51:05 +00008 <title>LLVM 2.8 Release Notes</title>
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10<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +000011
Dan Gohmanb44f6c62010-05-03 23:51:05 +000012<div class="doc_title">LLVM 2.8 Release Notes</div>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +000013
Chris Lattner0e464a92010-03-17 04:02:39 +000014<img align=right src="http://llvm.org/img/DragonSmall.png"
Gabor Greifee2187a2010-04-22 10:21:43 +000015 width="136" height="136" alt="LLVM Dragon Logo">
Chris Lattner0e464a92010-03-17 04:02:39 +000016
Chris Lattner79c3fe12003-10-02 04:57:28 +000017<ol>
Misha Brukman500bc302003-11-22 00:38:41 +000018 <li><a href="#intro">Introduction</a></li>
Chris Lattner96a445e2008-10-13 18:01:01 +000019 <li><a href="#subproj">Sub-project Status Update</a></li>
Dan Gohmanb44f6c62010-05-03 23:51:05 +000020 <li><a href="#externalproj">External Projects Using LLVM 2.8</a></li>
21 <li><a href="#whatsnew">What's New in LLVM 2.8?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +000022 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Dan Gohman44aa9212008-10-14 16:23:02 +000023 <li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +000024 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +000025</ol>
26
Chris Lattner7911ce22004-05-23 21:07:27 +000027<div class="doc_author">
Dan Gohman44aa9212008-10-14 16:23:02 +000028 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Misha Brukman500bc302003-11-22 00:38:41 +000029</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000030
Chris Lattnere07043c2010-09-29 05:30:03 +000031<!--
Chris Lattner7b91eda2010-04-22 05:41:35 +000032<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.8
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000033release.<br>
34You may prefer the
Dan Gohmanb44f6c62010-05-03 23:51:05 +000035<a href="http://llvm.org/releases/2.7/docs/ReleaseNotes.html">LLVM 2.7
36Release Notes</a>.</h1>
Chris Lattnere07043c2010-09-29 05:30:03 +000037-->
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000038
Chris Lattner79c3fe12003-10-02 04:57:28 +000039<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +000040<div class="doc_section">
41 <a name="intro">Introduction</a>
42</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000043<!-- *********************************************************************** -->
44
Misha Brukman500bc302003-11-22 00:38:41 +000045<div class="doc_text">
46
Chris Lattnerf6662f92008-10-13 17:57:36 +000047<p>This document contains the release notes for the LLVM Compiler
Dan Gohman7ae3ac82010-05-03 23:52:21 +000048Infrastructure, release 2.8. Here we describe the status of LLVM, including
Chris Lattnerf6662f92008-10-13 17:57:36 +000049major improvements from the previous release and significant known problems.
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +000050All LLVM releases may be downloaded from the <a
Chris Lattnerf6662f92008-10-13 17:57:36 +000051href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +000052
Chris Lattner7506b1d2004-12-07 08:04:13 +000053<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +000054release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +000055web site</a>. If you have questions or comments, the <a
Chris Lattnerc66bfef2010-03-17 04:41:49 +000056href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's
57Mailing List</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +000058
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +000059<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner84977642007-09-21 03:54:09 +000060main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greiffa933f82008-10-14 11:00:32 +000061current one. To see the release notes for a specific release, please see the
Chris Lattner84977642007-09-21 03:54:09 +000062<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +000063
64</div>
Chris Lattner61358ab2009-10-13 17:48:04 +000065
Chris Lattner79c3fe12003-10-02 04:57:28 +000066
Chris Lattner61358ab2009-10-13 17:48:04 +000067<!--
68Almost dead code.
69 include/llvm/Analysis/LiveValues.h => Dan
70 lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8.
Chris Lattner61c70e92010-08-28 04:09:24 +000071 GEPSplitterPass
Chris Lattner61358ab2009-10-13 17:48:04 +000072-->
73
74
Chris Lattnere07043c2010-09-29 05:30:03 +000075<!-- Features that need text if they're finished for 2.9:
Chris Lattner914ce462010-04-22 06:28:20 +000076 combiner-aa?
Chris Lattner61358ab2009-10-13 17:48:04 +000077 strong phi elim
Chris Lattner61358ab2009-10-13 17:48:04 +000078 loop dependence analysis
Chris Lattner885b6612010-08-28 16:33:36 +000079 TBAA
Chris Lattnere07043c2010-09-29 05:30:03 +000080 CorrelatedValuePropagation
Chris Lattneracce85d2008-02-10 07:46:44 +000081 -->
Chris Lattnere07043c2010-09-29 05:30:03 +000082
83 <!-- Announcement, lldb, libc++ -->
Chris Lattnerafa41632010-09-29 07:25:03 +000084
Chris Lattneracce85d2008-02-10 07:46:44 +000085
Chris Lattner96a445e2008-10-13 18:01:01 +000086<!-- *********************************************************************** -->
87<div class="doc_section">
88 <a name="subproj">Sub-project Status Update</a>
Chris Lattnerea34f642008-06-08 21:34:41 +000089</div>
Chris Lattner96a445e2008-10-13 18:01:01 +000090<!-- *********************************************************************** -->
Chris Lattnerea34f642008-06-08 21:34:41 +000091
92<div class="doc_text">
Chris Lattner8348b472008-06-08 21:58:17 +000093<p>
Dan Gohmanb44f6c62010-05-03 23:51:05 +000094The LLVM 2.8 distribution currently consists of code from the core LLVM
Chris Lattner61358ab2009-10-13 17:48:04 +000095repository (which roughly includes the LLVM optimizers, code generators
96and supporting tools), the Clang repository and the llvm-gcc repository. In
97addition to this code, the LLVM Project includes other sub-projects that are in
98development. Here we include updates on these subprojects.
Bill Wendling63d8c552009-03-02 04:28:57 +000099</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000100
Chris Lattner8348b472008-06-08 21:58:17 +0000101</div>
102
Chris Lattner96a445e2008-10-13 18:01:01 +0000103
Chris Lattner8348b472008-06-08 21:58:17 +0000104<!--=========================================================================-->
Chris Lattner96a445e2008-10-13 18:01:01 +0000105<div class="doc_subsection">
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000106<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000107</div>
108
109<div class="doc_text">
110
Chris Lattner095539f2010-04-26 17:42:18 +0000111<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
112C++, and Objective-C languages. Clang aims to provide a better user experience
113through expressive diagnostics, a high level of conformance to language
114standards, fast compilation, and low memory use. Like LLVM, Clang provides a
115modular, library-based architecture that makes it suitable for creating or
116integrating with other development tools. Clang is considered a
Chris Lattnere07043c2010-09-29 05:30:03 +0000117production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
118(32- and 64-bit), and for darwin-arm targets.</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000119
Chris Lattner922d00f2010-07-21 15:57:40 +0000120<p>In the LLVM 2.8 time-frame, the Clang team has made many improvements:</p>
Bill Wendling741748a2008-10-27 09:27:33 +0000121
Daniel Dunbar13739432008-10-14 23:25:09 +0000122<ul>
Chris Lattnere07043c2010-09-29 05:30:03 +0000123<li>Surely these guys have done something</li>
Chris Lattner4ba2b652010-09-30 16:31:33 +0000124<li>X86-64 abi improvements? Did they make it in?</li>
Bill Wendling6bc15282009-03-02 04:28:18 +0000125</ul>
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000126</div>
127
128<!--=========================================================================-->
129<div class="doc_subsection">
130<a name="clangsa">Clang Static Analyzer</a>
131</div>
132
133<div class="doc_text">
134
Chris Lattner8cdd7932010-04-22 06:38:11 +0000135<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a>
136 project is an effort to use static source code analysis techniques to
137 automatically find bugs in C and Objective-C programs (and hopefully <a
138 href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the
139 future</a>!). The tool is very good at finding bugs that occur on specific
140 paths through code, such as on error conditions.</p>
Chris Lattnercc042612008-10-14 00:52:49 +0000141
Chris Lattner2e38c7f2010-09-30 00:34:43 +0000142<p>The LLVM 2.8 release fixes a number of bugs and slightly improves precision
143 over 2.7, but there are no major new features in the release.
Chris Lattner8cdd7932010-04-22 06:38:11 +0000144</p>
Chris Lattner8348b472008-06-08 21:58:17 +0000145
146</div>
147
Chris Lattner96a445e2008-10-13 18:01:01 +0000148<!--=========================================================================-->
149<div class="doc_subsection">
Duncan Sands749fd832010-04-02 09:23:15 +0000150<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
Chris Lattner61358ab2009-10-13 17:48:04 +0000151</div>
152
153<div class="doc_text">
154<p>
Duncan Sands749fd832010-04-02 09:23:15 +0000155<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000156gcc-4.5. Unlike llvm-gcc, dragonegg in theory does not require any gcc-4.5
157modifications whatsoever (currently one small patch is needed) thanks to the
158new <a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>.
159DragonEgg is a gcc plugin that makes gcc-4.5 use the LLVM optimizers and code
160generators instead of gcc's, just like with llvm-gcc.
Duncan Sands749fd832010-04-02 09:23:15 +0000161</p>
162
163<p>
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000164DragonEgg is still a work in progress, but it is able to compile a lot of code,
165for example all of gcc, LLVM and clang. Currently Ada, C, C++ and Fortran work
166well, while all other languages either don't work at all or only work poorly.
167For the moment only the x86-32 and x86-64 targets are supported, and only on
168linux and darwin (darwin may need additional gcc patches).
Duncan Sands749fd832010-04-02 09:23:15 +0000169</p>
170
171<p>
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000172The 2.8 release has the following notable changes:
173<ul>
174<li>The plugin loads faster due to exporting fewer symbols.</li>
175<li>Additional vector operations such as addps256 are now supported.</li>
176<li>Ada global variables with no initial value are no longer zero initialized,
177resulting in better optimization.</li>
178<li>The '-fplugin-arg-dragonegg-enable-gcc-optzns' flag now runs all gcc
179optimizers, rather than just a handful.</li>
180<li>Fortran programs using common variables now link correctly.</li>
181<li>GNU OMP constructs no longer crash the compiler.</li>
182</ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000183</p>
184
185</div>
186
Chris Lattner75547712010-10-03 23:49:06 +0000187<!--=========================================================================-->
188<div class="doc_subsection">
189<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
190</div>
191
192<div class="doc_text">
193<p>
194The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
195a Java Virtual Machine (Java VM or JVM) that uses LLVM for static and
196just-in-time compilation. As of LLVM 2.8, VMKit now supports copying garbage
197collectors, and can be configured to use MMTk's copy mark-sweep garbage
198collector. In LLVM 2.8, the VMKit .NET VM is no longer being maintained.
199</p>
200</div>
201
202<!--=========================================================================-->
203<div class="doc_subsection">
204<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
205</div>
206
207<div class="doc_text">
208<p>
209The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
210is a simple library that provides an implementation of the low-level
211target-specific hooks required by code generation and other runtime components.
212For example, when compiling for a 32-bit target, converting a double to a 64-bit
213unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
214function. The compiler-rt library provides highly optimized implementations of
215this and other low-level routines (some are 3x faster than the equivalent
216libgcc routines).</p>
217
218<p>
219All of the code in the compiler-rt project is available under the standard LLVM
220License, a "BSD-style" license. New in LLVM 2.8, compiler_rt now supports
221soft floating point (for targets that don't have a real floating point unit),
222and includes an extensive testsuite for the "blocks" language feature and the
223blocks runtime included in compiler_rt.</p>
224
225</div>
Chris Lattner61358ab2009-10-13 17:48:04 +0000226
227<!--=========================================================================-->
228<div class="doc_subsection">
Chris Lattnere07043c2010-09-29 05:30:03 +0000229<a name="lldb">LLDB: Low Level Debugger</a>
230</div>
231
232<div class="doc_text">
233<p>
Chris Lattner75547712010-10-03 23:49:06 +0000234<a href="http://lldb.llvm.org/">LLDB</a> is a brand new member of the LLVM
235umbrella of projects. LLDB is a next generation, high-performance debugger. It
236is built as a set of reusable components which highly leverage existing
237libraries in the larger LLVM Project, such as the Clang expression parser, the
238LLVM disassembler and the LLVM JIT.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000239
240<p>
Chris Lattner75547712010-10-03 23:49:06 +0000241LLDB is in early development and not included as part of the LLVM 2.8 release,
242but is mature enough to support basic debugging scenarios on Mac OS X in C,
243Objective-C and C++. We'd really like help extending and expanding LLDB to
244support new platforms, new languages, new architectures, and new features.
Chris Lattnere07043c2010-09-29 05:30:03 +0000245</p>
246
247</div>
248
249<!--=========================================================================-->
250<div class="doc_subsection">
251<a name="libc++">libc++: C++ Standard Library</a>
252</div>
253
254<div class="doc_text">
255<p>
Chris Lattner75547712010-10-03 23:49:06 +0000256<a href="http://libc++.llvm.org/">libc++</a> is another new member of the LLVM
257family. It is an implementation of the C++ standard library, written from the
258ground up to specifically target the forthcoming C++'0X standard and focus on
259delivering great performance.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000260
261<p>
Chris Lattner75547712010-10-03 23:49:06 +0000262As of the LLVM 2.8 release, libc++ is virtually feature complete, but would
263benefit from more testing and better integration with Clang++. It is also
264looking forward to the C++ committee finalizing the C++'0x standard.
Chris Lattnere07043c2010-09-29 05:30:03 +0000265</p>
266
267</div>
268
Chris Lattner61358ab2009-10-13 17:48:04 +0000269
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000270<!-- *********************************************************************** -->
271<div class="doc_section">
Chris Lattner922d00f2010-07-21 15:57:40 +0000272 <a name="externalproj">External Open Source Projects Using LLVM 2.8</a>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000273</div>
274<!-- *********************************************************************** -->
275
Chris Lattner61358ab2009-10-13 17:48:04 +0000276<div class="doc_text">
277
278<p>An exciting aspect of LLVM is that it is used as an enabling technology for
279 a lot of other language and tools projects. This section lists some of the
Chris Lattner922d00f2010-07-21 15:57:40 +0000280 projects that have already been updated to work with LLVM 2.8.</p>
Chris Lattner7c8e7962010-04-26 17:38:10 +0000281</div>
282
Chris Lattner2e38c7f2010-09-30 00:34:43 +0000283<!--=========================================================================-->
284<div class="doc_subsection">
285<a name="tce">TTA-based Codesign Environment (TCE)</a>
286</div>
287
288<div class="doc_text">
289<p>
290<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing
291application-specific processors (ASP) based on the Transport triggered
292architecture (TTA). The toolset provides a complete co-design flow from C/C++
293programs down to synthesizable VHDL and parallel program binaries. Processor
294customization points include the register files, function units, supported
295operations, and the interconnection network.</p>
296
297<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target
298independent optimizations and also for parts of code generation. It generates
299new LLVM-based code generators "on the fly" for the designed TTA processors and
300loads them in to the compiler backend as runtime libraries to avoid per-target
301recompilation of larger parts of the compiler chain.</p>
302
303</div>
304
305<!--=========================================================================-->
306<div class="doc_subsection">
307<a name="Horizon">Horizon Bytecode Compiler</a>
308</div>
309
310<div class="doc_text">
311<p>
312<a href="http://www.quokforge.org/projects/horizon">Horizon</a> is a bytecode
313language and compiler written on top of LLVM, intended for producing
314single-address-space managed code operating systems that
315run faster than the equivalent multiple-address-space C systems.
316More in-depth blurb is available on <a
317href="http://www.quokforge.org/projects/horizon/wiki/Wiki">the wiki</a>.</p>
318
319</div>
320
321<!--=========================================================================-->
322<div class="doc_subsection">
323<a name="clamav">Clam AntiVirus</a>
324</div>
325
326<div class="doc_text">
327<p>
328<a href=http://www.clamav.net>Clam AntiVirus</a> is an open source (GPL)
329anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail
330gateways. Since version 0.96 it has <a
331href="http://vrt-sourcefire.blogspot.com/2010/09/introduction-to-clamavs-low-level.html">bytecode
332signatures</a> that allow writing detections for complex malware. It
333uses LLVM's JIT to speed up the execution of bytecode on
334X86,X86-64,PPC32/64, falling back to its own interpreter otherwise.
335The git version was updated to work with LLVM 2.8
336</p>
337
338<p>The <a
339href="http://git.clamav.net/gitweb?p=clamav-bytecode-compiler.git;a=blob_plain;f=docs/user/clambc-user.pdf">
340ClamAV bytecode compiler</a> uses Clang and LLVM to compile a C-like
341language, insert runtime checks, and generate ClamAV bytecode.</p>
342
343</div>
344
345<!--=========================================================================-->
346<div class="doc_subsection">
347<a name="pure">Pure</a>
348</div>
349
350<div class="doc_text">
351<p>
352<a href="http://pure-lang.googlecode.com/">Pure</a>
353is an algebraic/functional
354programming language based on term rewriting. Programs are collections
355of equations which are used to evaluate expressions in a symbolic
356fashion. Pure offers dynamic typing, eager and lazy evaluation, lexical
357closures, a hygienic macro system (also based on term rewriting),
358built-in list and matrix support (including list and matrix
359comprehensions) and an easy-to-use C interface. The interpreter uses
360LLVM as a backend to JIT-compile Pure programs to fast native code.</p>
361
362<p>Pure versions 0.44 and later have been tested and are known to work with
363LLVM 2.8 (and continue to work with older LLVM releases >= 2.5).</p>
364
365</div>
366
367<!--=========================================================================-->
368<div class="doc_subsection">
369<a name="GHC">Glasgow Haskell Compiler (GHC)</a>
370</div>
371
372<div class="doc_text">
373<p>
374<a href="http://www.haskell.org/ghc/">GHC</a> is an open source,
375state-of-the-art programming suite for
376Haskell, a standard lazy functional programming language. It includes
377an optimizing static compiler generating good code for a variety of
378platforms, together with an interactive system for convenient, quick
379development.</p>
380
381<p>In addition to the existing C and native code generators, GHC 7.0 now
382supports an <a
383href="http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/Backends/LLVM">LLVM
384code generator</a>. GHC supports LLVM 2.7 and later.</p>
385
386</div>
387
388<!--=========================================================================-->
389<div class="doc_subsection">
390<a name="Clay">Clay Programming Language</a>
391</div>
392
393<div class="doc_text">
394<p>
Chris Lattner97fe6452010-09-30 01:12:09 +0000395<a href="http://tachyon.in/clay/">Clay</a> is a new systems programming
Chris Lattner2e38c7f2010-09-30 00:34:43 +0000396language that is specifically designed for generic programming. It makes
397generic programming very concise thanks to whole program type propagation. It
398uses LLVM as its backend.</p>
399
400</div>
Chris Lattner3a1d4cf2010-04-22 21:34:16 +0000401
Chris Lattnere0518442010-10-01 06:34:49 +0000402<!--=========================================================================-->
403<div class="doc_subsection">
404<a name="llvm-py">llvm-py Python Bindings for LLVM</a>
405</div>
406
407<div class="doc_text">
408<p>
409<a href="http://www.mdevan.org/llvm-py/">llvm-py</a> has been updated to work
410with LLVM 2.8. llvm-py provides Python bindings for LLVM, allowing you to write a
411compiler backend or a VM in Python.</p>
412
413</div>
414
415
Chris Lattner2fb6e5c2010-10-03 23:09:03 +0000416<!--=========================================================================-->
417<div class="doc_subsection">
418<a name="FAUST">FAUST Real-Time Audio Signal Processing Language</a>
419</div>
420
421<div class="doc_text">
422<p>
423<a href="http://faust.grame.fr">FAUST</a> is a compiled language for real-time
424audio signal processing. The name FAUST stands for Functional AUdio STream. Its
425programming model combines two approaches: functional programming and block
426diagram composition. In addition with the C, C++, JAVA output formats, the
427Faust compiler can now generate LLVM bitcode, and works with LLVM 2.7 and
4282.8.</p>
429
430</div>
431
432<!--=========================================================================-->
433<div class="doc_subsection">
434<a name="jade">Jade Just-in-time Adaptive Decoder Engine</a>
435</div>
436
437<div class="doc_text">
438<p><a
439href="http://sourceforge.net/apps/trac/orcc/wiki/JadeDocumentation">Jade</a>
440(Just-in-time Adaptive Decoder Engine) is a generic video decoder engine using
441LLVM for just-in-time compilation of video decoder configurations. Those
442configurations are designed by MPEG Reconfigurable Video Coding (RVC) committee.
443MPEG RVC standard is built on a stream-based dataflow representation of
444decoders. It is composed of a standard library of coding tools written in
445RVC-CAL language and a dataflow configuration &emdash; block diagram &emdash;
446of a decoder.</p>
447
448<p>Jade project is hosted as part of the <a href="http://orcc.sf.net">Open
449RVC-CAL Compiler</a> and requires it to translate the RVC-CAL standard library
450of video coding tools into an LLVM assembly code.</p>
451
452</div>
453
454<!--=========================================================================-->
455<div class="doc_subsection">
456<a name="neko_llvm_jit">LLVM JIT for Neko VM</a>
457</div>
458
459<div class="doc_text">
460<p><a href="http://github.com/vava/neko_llvm_jit">Neko LLVM JIT</a>
461replaces the standard Neko JIT with an LLVM-based implementation. While not
462fully complete, it is already providing a 1.5x speedup on 64-bit systems.
463Neko LLVM JIT requires LLVM 2.8 or later.</p>
464
465</div>
466
467<!--=========================================================================-->
468<div class="doc_subsection">
469<a name="crack">Crack Scripting Language</a>
470</div>
471
472<div class="doc_text">
473<p>
474<a href="http://code.google.com/p/crack-language/">Crack</a> aims to provide
475the ease of development of a scripting language with the performance of a
476compiled language. The language derives concepts from C++, Java and Python,
477incorporating object-oriented programming, operator overloading and strong
478typing. Crack 0.2 works with LLVM 2.7, and the forthcoming Crack 0.2.1 release
479builds on LLVM 2.8.</p>
480
481</div>
482
483<!--=========================================================================-->
484<div class="doc_subsection">
485<a name="DresdenTM">Dresden TM Compiler (DTMC)</a>
486</div>
487
488<div class="doc_text">
489<p>
490<a href="http://tm.inf.tu-dresden.de">DTMC</a> provides support for
491Transactional Memory, which is an easy-to-use and efficient way to synchronize
492accesses to shared memory. Transactions can contain normal C/C++ code (e.g.,
493__transaction { list.remove(x); x.refCount--; }) and will be executed
494virtually atomically and isolated from other transactions.</p>
495
496</div>
497
498<!--=========================================================================-->
499<div class="doc_subsection">
500<a name="Kai">Kai Interpreter</a>
501</div>
502
503<div class="doc_text">
504<p>
505<a href="http://www.oriontransfer.co.nz/research/kai">Kai</a> (Japanese 会 for
506meeting/gathering) is an experimental interpreter that provides a highly
507extensible runtime environment and explicit control over the compilation
508process. Programs are defined using nested symbolic expressions, which are all
509parsed into first-class values with minimal intrinsic semantics. Kai can
510generate optimised code at run-time (using LLVM) in order to exploit the nature
511of the underlying hardware and to integrate with external software libraries.
512It is a unique exploration into world of dynamic code compilation, and the
513interaction between high level and low level semantics.</p>
514
515</div>
516
Chris Lattner75547712010-10-03 23:49:06 +0000517<!--=========================================================================-->
518<div class="doc_subsection">
519<a name="OSL">OSL: Open Shading Language</a>
520</div>
521
522<div class="doc_text">
523<p>
524<a href="http://code.google.com/p/openshadinglanguage/">OSL</a> is a shading
525language designed for use in physically based renderers and in particular
526production rendering. By using LLVM instead of the interpreter, it was able to
527meet its performance goals (&gt;= C-code) while retaining the benefits of
528runtime specialization and a portable high-level language.
529</p>
530
531</div>
532
533
Chris Lattnere0518442010-10-01 06:34:49 +0000534
Chris Lattner8348b472008-06-08 21:58:17 +0000535<!-- *********************************************************************** -->
536<div class="doc_section">
Chris Lattner922d00f2010-07-21 15:57:40 +0000537 <a name="whatsnew">What's New in LLVM 2.8?</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000538</div>
539<!-- *********************************************************************** -->
540
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000541<div class="doc_text">
542
Chris Lattner61358ab2009-10-13 17:48:04 +0000543<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattnerf6662f92008-10-13 17:57:36 +0000544minor improvements. Some of the major improvements and new features are listed
545in this section.
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000546</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000547
Chris Lattner914ce462010-04-22 06:28:20 +0000548</div>
549
550<!--=========================================================================-->
551<div class="doc_subsection">
552<a name="orgchanges">LLVM Community Changes</a>
553</div>
554
555<div class="doc_text">
556
Chris Lattner922d00f2010-07-21 15:57:40 +0000557<p>In addition to changes to the code, between LLVM 2.7 and 2.8, a number of
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000558organization changes have happened:
559</p>
560
561<ul>
Chris Lattnere07043c2010-09-29 05:30:03 +0000562<li>libc++ and lldb are new</li>
Chris Lattnerafa41632010-09-29 07:25:03 +0000563<li>Debugging optimized code support.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000564</ul>
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000565</div>
566
Chris Lattner8348b472008-06-08 21:58:17 +0000567<!--=========================================================================-->
Chris Lattnerea34f642008-06-08 21:34:41 +0000568<div class="doc_subsection">
Chris Lattner252b83d2008-02-06 18:00:06 +0000569<a name="majorfeatures">Major New Features</a>
570</div>
571
572<div class="doc_text">
573
Chris Lattner922d00f2010-07-21 15:57:40 +0000574<p>LLVM 2.8 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000575
576<ul>
Chris Lattner702f2d42010-09-06 19:14:40 +0000577<li>llvm-diff</li>
Chris Lattner4eac9242010-10-02 22:44:15 +0000578<li>Direct .o file writing support for darwin/x86[64].</li>
Chris Lattner8170c102008-02-10 08:18:42 +0000579</ul>
Chris Lattnerdc910082010-03-17 06:41:58 +0000580
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000581</div>
582
Chris Lattner84977642007-09-21 03:54:09 +0000583<!--=========================================================================-->
584<div class="doc_subsection">
Chris Lattner917cc712009-03-02 02:37:32 +0000585<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000586</div>
587
588<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000589<p>LLVM IR has several new features for better support of new targets and that
590expose new optimization opportunities:</p>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000591
Chris Lattner791f77b2008-06-05 06:25:56 +0000592<ul>
Gabor Greif17b59fe2010-07-21 10:20:08 +0000593
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000594 memcpy, memmove, and memset now take address space qualified pointers + volatile.
595 per-instruction debug info metadata is much faster and uses less space (new DebugLoc class).
596 New "trap values" concept: http://llvm.org/docs/LangRef.html#trapvalues
597 New linker_private_weak and linker_private_weak_def_auto linkage types
598 Triples are now stored in normalized form. Triple::normalize.
599
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000600</ul>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000601
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000602</div>
603
604<!--=========================================================================-->
605<div class="doc_subsection">
Chris Lattneracce85d2008-02-10 07:46:44 +0000606<a name="optimizer">Optimizer Improvements</a>
607</div>
608
609<div class="doc_text">
610
Chris Lattner61358ab2009-10-13 17:48:04 +0000611<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattnerf3013872008-10-13 21:50:36 +0000612release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000613
614<ul>
615
Chris Lattner922d00f2010-07-21 15:57:40 +0000616<li></li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000617 Preliminary work on TBAA but not usable in 2.8.
618 New CorrelatedValuePropagation pass, not on by default in 2.8 yet.
619 JumpThreading much more aggressive about implied value relations.
620 New RegionInfo pass "opt -regions analyze" or "opt -view-regions".
621 Improved trip count analysis for <= and >= loops, and uses sign overflow info.
622 llvm.dbg.value: variable debug info for optimized code
623 Now iterate function passes when a cgsccpassmanager detects a devirtualization
624 Atomic lowering patch: -loweratomic (see Passes.html#loweratomic)
Chris Lattnera54c1f72010-04-21 06:42:24 +0000625
Chris Lattner61358ab2009-10-13 17:48:04 +0000626</ul>
Chris Lattner917cc712009-03-02 02:37:32 +0000627
Chris Lattner61358ab2009-10-13 17:48:04 +0000628</div>
Chris Lattner917cc712009-03-02 02:37:32 +0000629
Chris Lattner917cc712009-03-02 02:37:32 +0000630
Chris Lattner61358ab2009-10-13 17:48:04 +0000631<!--=========================================================================-->
632<div class="doc_subsection">
633<a name="executionengine">Interpreter and JIT Improvements</a>
634</div>
Chris Lattnerf3013872008-10-13 21:50:36 +0000635
Chris Lattner61358ab2009-10-13 17:48:04 +0000636<div class="doc_text">
637
638<ul>
Chris Lattner922d00f2010-07-21 15:57:40 +0000639<li></li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000640
Chris Lattner0b832202008-06-08 02:45:07 +0000641</ul>
642
643</div>
644
645<!--=========================================================================-->
646<div class="doc_subsection">
Chris Lattner4ba2b652010-09-30 16:31:33 +0000647<a name="mc">MC Level Improvements</a>
648</div>
649
650<div class="doc_text">
651<p>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000652The LLVM Machine Code (aka MC) subsystem was created to solve a number
Chris Lattner4ba2b652010-09-30 16:31:33 +0000653of problems in the realm of assembly, disassembly, object file format handling,
654and a number of other related areas that CPU instruction-set level tools work
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000655in.</p>
656
657<p>The MC subproject has made great leaps in LLVM 2.8. For example, support for
658 directly writing .o files from LLC (and clang) now works reliably for
659 darwin/x86[-64] (including inline assembly support) and the integrated
660 assembler is turned on by default in Clang for these targets. This provides
661 improved compile times among other things.</p>
662
663<ul>
664<li>The entire compiler has converted over to using the MCStreamer assembler API
665 instead of writing out a .s file textually.</li>
666<li>The "assembler parser" is far more mature than in 2.7, supporting a full
667 complement of directives, now supports assembler macros, etc.</li>
668<li>The "assembler backend" has been completed, including support for relaxation
669 relocation processing and all the other things that an assembler does.</li>
670<li>The MachO file format support is now fully functional and works.</li>
671<li>The MC disassembler now fully supports ARM and Thumb. ARM assembler support
672 is still in early development though.</li>
673<li>The X86 MC assembler now supports the X86 AES and AVX instruction set.</li>
674<li>Work on ELF and COFF support is well underway, but isn't useful yet in LLVM
675 2.8. Please contact the llvmdev mailing list if you're interested in
676 this.</li>
677</ul>
678
679<p>For more information, please see the <a
Chris Lattner4ba2b652010-09-30 16:31:33 +0000680href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
681LLVM MC Project Blog Post</a>.
682</p>
683
Chris Lattner4ba2b652010-09-30 16:31:33 +0000684</div>
685
686
687
688<!--=========================================================================-->
689<div class="doc_subsection">
Chris Lattner511433e2009-03-02 03:24:11 +0000690<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner0b832202008-06-08 02:45:07 +0000691</div>
692
693<div class="doc_text">
694
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000695<p>We have put a significant amount of work into the code generator
696infrastructure, which allows us to implement more aggressive algorithms and make
697it run faster:</p>
Chris Lattner0b832202008-06-08 02:45:07 +0000698
699<ul>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000700<li></li>
701
702 MachineCSE tuned and on by default.
703
704 Rewrote tblgen's type inference for backends to be more consistent and
705 diagnose more target bugs. This also allows limited support for writing
706 patterns for instructions that return multiple results, e.g. a virtual
707 register and a flag result. Stuff that used 'parallel' before should use
708 this.
709
710 New -regalloc=fast, =local got removed
711 New -regalloc=default option that chooses a register allocator based on the -O optimization level.
712 New SubRegIndex tblgen class for targets -> jakob
713
714 Bottom up fast isel. Simple Load reuse. No more machinedce.
715 IR ABI: <3 x float> is passed as <4 x float> instead of 3 floats.
716
717 New COPY instruction. copyRegToReg -> copyPhysReg, isMoveInstr is gone.
718 RenderMachineFunction: -rendermf
719 SplitKit?
720 Evan: Teach bottom up pre-ra scheduler to track register pressure. Work in progress.
721 Evan: Add an ILP scheduler. On x86_64, this is a win for all tests in CFP2000. It also sped up 256.bzip2 by 16%.
722
723 New OptimizeExts+OptimizeCmps -> PeepholeOptimizer pass
724 New LocalStackSlotAllocation.cpp pass (jimg)
725 Atomics now get legalized when not natively supported (jim g)
726
727 -ffunction-sections and -fdata-sections are supported on ELF targets.
728 -momit-leaf-frame-pointer now supported.
729
Chris Lattner84977642007-09-21 03:54:09 +0000730</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000731</div>
732
Chris Lattner917cc712009-03-02 02:37:32 +0000733<!--=========================================================================-->
734<div class="doc_subsection">
735<a name="x86">X86-32 and X86-64 Target Improvements</a>
736</div>
737
738<div class="doc_text">
739<p>New features of the X86 target include:
740</p>
741
742<ul>
Chris Lattner922d00f2010-07-21 15:57:40 +0000743<li>The X86 backend now supports holding X87 floating point stack values
744 in registers across basic blocks, dramatically improving performance of code
745 that uses long double, and when targetting CPUs that don't support SSE.</li>
Chris Lattner511433e2009-03-02 03:24:11 +0000746
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000747 New SSEDomainFix pass:
748 On Nehalem and newer CPUs there is a 2 cycle latency penalty on using a
749 register in a different domain than where it was defined. Some instructions
750 have equvivalents for different domains, like por/orps/orpd. The
751 SSEDomainFix pass tries to minimize the number of domain crossings by
752 changing between equvivalent opcodes where possible.
753
754 X86 backend attempts to promote 16-bit integer operations to 32-bits to avoid
755 0x66 prefixes, which are slow on some microarchitectures and bloat the code
756 on others.
757
758 New support for X86 "thiscall" calling convention (x86_thiscallcc in IR) for windows.
759
760 New llvm.x86.int intrinsic (for int $42 and int3)
761
762 Verbose assembly decodes X86 shuffle instructions, e.g.:
763 insertps $113, %xmm3, %xmm0 ## xmm0 = zero,xmm0[1,2],xmm3[1]
764 unpcklps %xmm1, %xmm0 ## xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1]
765 pshufd $1, %xmm1, %xmm1 ## xmm1 = xmm1[1,0,0,0]
766
767 X86 ABI: <2 x float> in IR no longer maps onto MMX, it turns into <4 x float>
768
769 new GHC calling convention
770
Chris Lattner917cc712009-03-02 02:37:32 +0000771</ul>
772
Chris Lattner917cc712009-03-02 02:37:32 +0000773</div>
Chris Lattner84977642007-09-21 03:54:09 +0000774
775<!--=========================================================================-->
776<div class="doc_subsection">
Chris Lattner61358ab2009-10-13 17:48:04 +0000777<a name="ARM">ARM Target Improvements</a>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000778</div>
779
780<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000781<p>New features of the ARM target include:
782</p>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000783
784<ul>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000785
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000786 NEON: Better performance for QQQQ (4-consecutive Q register) instructions. New reg sequence abstraction?
787 ARM: Better scheduling (list-hybrid, hybrid?)
788 ARM: Tail call support.
789 ARM: General performance work and tuning.
790
791 ARM: Half float support through intrinsics LangRef.html#int_fp16
792<li>ARMGlobalMerge: <!-- Anton --> </li>
793
Chris Lattner4eac9242010-10-02 22:44:15 +0000794<li>The ARM NEON intrinsics have been substantially reworked to reduce
795 redundancy and improve code generation. Some of the major changes are:
796 <ol>
797 <li>
798 All of the NEON load and store intrinsics (llvm.arm.neon.vld* and
799 llvm.arm.neon.vst*) take an extra parameter to specify the alignment in bytes
800 of the memory being accessed.
801 </li>
802 <li>
803 The llvm.arm.neon.vaba intrinsic (vector absolute difference and
804 accumulate) has been removed. This operation is now represented using
805 the llvm.arm.neon.vabd intrinsic (vector absolute difference) followed by a
806 vector add.
807 </li>
808 <li>
809 The llvm.arm.neon.vabdl and llvm.arm.neon.vabal intrinsics (lengthening
810 vector absolute difference with and without accumlation) have been removed.
811 They are represented using the llvm.arm.neon.vabd intrinsic (vector absolute
812 difference) followed by a vector zero-extend operation, and for vabal,
813 a vector add.
814 </li>
815 <li>
816 The llvm.arm.neon.vmovn intrinsic has been removed. Calls of this intrinsic
817 are now replaced by vector truncate operations.
818 </li>
819 <li>
820 The llvm.arm.neon.vmovls and llvm.arm.neon.vmovlu intrinsics have been
821 removed. They are now represented as vector sign-extend (vmovls) and
822 zero-extend (vmovlu) operations.
823 </li>
824 <li>
825 The llvm.arm.neon.vaddl*, llvm.arm.neon.vaddw*, llvm.arm.neon.vsubl*, and
826 llvm.arm.neon.vsubw* intrinsics (lengthening vector add and subtract) have
827 been removed. They are replaced by vector add and vector subtract operations
828 where one (vaddw, vsubw) or both (vaddl, vsubl) of the operands are either
829 sign-extended or zero-extended.
830 </li>
831 <li>
832 The llvm.arm.neon.vmulls, llvm.arm.neon.vmullu, llvm.arm.neon.vmlal*, and
833 llvm.arm.neon.vmlsl* intrinsics (lengthening vector multiply with and without
834 accumulation and subtraction) have been removed. These operations are now
835 represented as vector multiplications where the operands are either
836 sign-extended or zero-extended, followed by a vector add for vmlal or a
837 vector subtract for vmlsl. Note that the polynomial vector multiply
838 intrinsic, llvm.arm.neon.vmullp, remains unchanged.
839 </li>
840 </ol>
Bob Wilson5b2fb952010-09-13 17:37:55 +0000841</li>
Bob Wilsone8472772010-09-13 17:39:35 +0000842</ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000843</div>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000844
Chris Lattner61358ab2009-10-13 17:48:04 +0000845<!--=========================================================================-->
846<div class="doc_subsection">
Chris Lattner61358ab2009-10-13 17:48:04 +0000847<a name="newapis">New Useful APIs</a>
848</div>
849
850<div class="doc_text">
851
852<p>This release includes a number of new APIs that are used internally, which
853 may also be useful for external clients.
854</p>
855
856<ul>
Chris Lattner922d00f2010-07-21 15:57:40 +0000857<li></li>
Chris Lattner61358ab2009-10-13 17:48:04 +0000858</ul>
859
860
861</div>
862
863<!--=========================================================================-->
864<div class="doc_subsection">
865<a name="otherimprovements">Other Improvements and New Features</a>
866</div>
867
868<div class="doc_text">
869<p>Other miscellaneous features include:</p>
870
871<ul>
Chris Lattner922d00f2010-07-21 15:57:40 +0000872<li></li>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000873</ul>
874
875</div>
876
Chris Lattner77d29b12008-06-05 08:02:49 +0000877
878<!--=========================================================================-->
879<div class="doc_subsection">
Chris Lattnerf6662f92008-10-13 17:57:36 +0000880<a name="changes">Major Changes and Removed Features</a>
881</div>
882
883<div class="doc_text">
884
Chris Lattnereeb4da02008-10-13 22:06:31 +0000885<p>If you're already an LLVM user or developer with out-of-tree changes based
Chris Lattner922d00f2010-07-21 15:57:40 +0000886on LLVM 2.7, this section lists some "gotchas" that you may run into upgrading
Chris Lattnereeb4da02008-10-13 22:06:31 +0000887from the previous release.</p>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000888
889<ul>
Chris Lattnerbb117712010-10-04 01:29:06 +0000890<li>The build configuration machinery changed the output directory names. It
891 wasn't clear to many people that "Release-Asserts" build was a release build
892 without asserts. To make this more clear, "Release" does not include
893 assertions and "Release+Asserts" does (likewise, "Debug" and
894 "Debug+Asserts").</li>
895<li>The MSIL Backend was removed, it was unsupported and broken.</li>
896<li>The ABCD, SSI, and SCCVN passes were removed. These were not fully
897 functional and their behavior has been or will be subsumed by the
898 LazyValueInfo pass.</li>
899<li>The LLVM IR 'Union' feature was removed. While this is a desirable feature
900 for LLVM IR to support, the existing implementation was half baked and
901 barely useful. We'd really like anyone interested to resurrect the work and
902 finish it for a future release.</li>
903<li>If you're used to reading .ll files, you'll probably notice that .ll file
904 dumps don't produce #uses comments anymore. To get them, run a .bc file
905 through "llvm-dis --show-annotations".</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000906</ul>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000907
Chris Lattnerbb117712010-10-04 01:29:06 +0000908
909
Chris Lattnereeb4da02008-10-13 22:06:31 +0000910<p>In addition, many APIs have changed in this release. Some of the major LLVM
911API changes are:</p>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000912<ul>
Chris Lattner4eac9242010-10-02 22:44:15 +0000913<li>LLVM 2.8 changes the internal order of operands in <a
914 href="http://llvm.org/doxygen/classllvm_1_1InvokeInst.html"><tt>InvokeInst</tt></a>
915 and <a href="http://llvm.org/doxygen/classllvm_1_1CallInst.html"><tt>CallInst</tt></a>.
Chris Lattnerbb117712010-10-04 01:29:06 +0000916 To be portable across releases, please use the <tt>CallSite</tt> class and the
917 high-level accessors, such as <tt>getCalledValue</tt> and
918 <tt>setUnwindDest</tt>.
Chris Lattner4eac9242010-10-02 22:44:15 +0000919</li>
920<li>
Chris Lattnerbb117712010-10-04 01:29:06 +0000921 You can no longer pass use_iterators directly to cast&lt;&gt; (and similar),
922 because these routines tend to perform costly dereference operations more
923 than once. You have to dereference the iterators yourself and pass them in.
Chris Lattner4eac9242010-10-02 22:44:15 +0000924</li>
925<li>
Chris Lattnerbb117712010-10-04 01:29:06 +0000926 llvm.memcpy.*, llvm.memset.*, llvm.memmove.* intrinsics take an extra
927 parameter now ("i1 isVolatile"), totaling 5 parameters, and the pointer
928 operands are now address-space qualified.
Chris Lattner4eac9242010-10-02 22:44:15 +0000929 If you were creating these intrinsic calls and prototypes yourself (as opposed
Chris Lattnerbb117712010-10-04 01:29:06 +0000930 to using Intrinsic::getDeclaration), you can use
931 UpgradeIntrinsicFunction/UpgradeIntrinsicCall to be portable accross releases.
Chris Lattner4eac9242010-10-02 22:44:15 +0000932</li>
933<li>
934 SetCurrentDebugLocation takes a DebugLoc now instead of a MDNode.
935 Change your code to use
936 SetCurrentDebugLocation(DebugLoc::getFromDILocation(...)).
937</li>
938<li>
Chris Lattner4eac9242010-10-02 22:44:15 +0000939 The <tt>RegisterPass</tt> and <tt>RegisterAnalysisGroup</tt> templates are
940 considered deprecated, but continue to function in LLVM 2.8. Clients are
941 strongly advised to use the upcoming <tt>INITIALIZE_PASS()</tt> and
942 <tt>INITIALIZE_AG_PASS()</tt> macros instead.
Chris Lattner4eac9242010-10-02 22:44:15 +0000943</li>
944<li>
945 The constructor for the Triple class no longer tries to understand odd triple
946 specifications. Frontends should ensure that they only pass valid triples to
947 LLVM. The Triple::normalize utility method has been added to help front-ends
948 deal with funky triples.
Chris Lattnerbb117712010-10-04 01:29:06 +0000949</li>
950
Chris Lattner4eac9242010-10-02 22:44:15 +0000951<li>
952 Some APIs got renamed:
953 <ul>
Chris Lattnerbb117712010-10-04 01:29:06 +0000954 <li>llvm_report_error -&gt; report_fatal_error</li>
955 <li>llvm_install_error_handler -&gt; install_fatal_error_handler</li>
956 <li>llvm::DwarfExceptionHandling -&gt; llvm::JITExceptionHandling</li>
957 <li>VISIBILITY_HIDDEN -&gt; LLVM_LIBRARY_VISIBILITY</li>
Chris Lattner4eac9242010-10-02 22:44:15 +0000958 </ul>
959</li>
960
Devang Patelb34dd132008-10-14 20:03:43 +0000961</ul>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000962
Chris Lattnerf6662f92008-10-13 17:57:36 +0000963</div>
964
965
Chris Lattner79c3fe12003-10-02 04:57:28 +0000966<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000967<div class="doc_section">
968 <a name="knownproblems">Known Problems</a>
969</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000970<!-- *********************************************************************** -->
971
Misha Brukman500bc302003-11-22 00:38:41 +0000972<div class="doc_text">
973
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000974<p>This section contains significant known problems with the LLVM system,
Chris Lattnere18b32e2008-11-10 05:40:34 +0000975listed by component. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000976href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000977there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000978
Misha Brukman500bc302003-11-22 00:38:41 +0000979</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000980
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000981<!-- ======================================================================= -->
982<div class="doc_subsection">
983 <a name="experimental">Experimental features included with this release</a>
984</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000985
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000986<div class="doc_text">
987
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000988<p>The following components of this LLVM release are either untested, known to
989be broken or unreliable, or are in early development. These components should
990not be relied on, and bugs should not be filed against them, but they may be
991useful to some people. In particular, if you would like to work on one of these
Chris Lattner2b659ef2008-02-12 06:29:45 +0000992components, please contact us on the <a
993href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000994
995<ul>
Chris Lattnerbb117712010-10-04 01:29:06 +0000996<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, PIC16, SystemZ
997 and XCore backends are experimental.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000998<li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets
999 other than darwin-i386 and darwin-x86_64.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +00001000</ul>
1001
1002</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +00001003
Misha Brukman500bc302003-11-22 00:38:41 +00001004<!-- ======================================================================= -->
1005<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +00001006 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +00001007</div>
1008
1009<div class="doc_text">
1010
1011<ul>
Anton Korobeynikova6094be2008-06-08 10:24:13 +00001012 <li>The X86 backend does not yet support
1013 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
1014 floating point stack</a>. It supports the 'f' and 't' constraints, but not
1015 'u'.</li>
Duncan Sands47eff2b2008-06-08 19:38:43 +00001016 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswell524a5dd2009-03-02 15:28:15 +00001017 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
Chris Lattner914ce462010-04-22 06:28:20 +00001018 runtime currently due to lack of support for the 'u' inline assembly
1019 constraint and for X87 floating point inline assembly.</li>
Dan Gohman8207ba92008-06-08 23:05:11 +00001020 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner914ce462010-04-22 06:28:20 +00001021 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman8207ba92008-06-08 23:05:11 +00001022 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattner26299222006-11-18 07:51:14 +00001023</ul>
1024
1025</div>
1026
1027<!-- ======================================================================= -->
1028<div class="doc_subsection">
1029 <a name="ppc-be">Known problems with the PowerPC back-end</a>
1030</div>
1031
1032<div class="doc_text">
1033
1034<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +00001035<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +00001036compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +00001037</ul>
1038
1039</div>
1040
1041<!-- ======================================================================= -->
1042<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +00001043 <a name="arm-be">Known problems with the ARM back-end</a>
1044</div>
1045
1046<div class="doc_text">
1047
1048<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +00001049<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +00001050processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +00001051results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswell524a5dd2009-03-02 15:28:15 +00001052<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattnerf3e5bc62007-05-14 06:56:09 +00001053</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +00001054</ul>
1055
1056</div>
1057
1058<!-- ======================================================================= -->
1059<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +00001060 <a name="sparc-be">Known problems with the SPARC back-end</a>
1061</div>
1062
1063<div class="doc_text">
1064
1065<ul>
John Criswell524a5dd2009-03-02 15:28:15 +00001066<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Chris Lattner26299222006-11-18 07:51:14 +00001067 support the 64-bit SPARC ABI (-m64).</li>
1068</ul>
1069
1070</div>
1071
1072<!-- ======================================================================= -->
1073<div class="doc_subsection">
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +00001074 <a name="mips-be">Known problems with the MIPS back-end</a>
1075</div>
1076
1077<div class="doc_text">
1078
1079<ul>
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +00001080<li>64-bit MIPS targets are not supported yet.</li>
1081</ul>
1082
1083</div>
1084
1085<!-- ======================================================================= -->
1086<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +00001087 <a name="alpha-be">Known problems with the Alpha back-end</a>
1088</div>
1089
1090<div class="doc_text">
1091
1092<ul>
1093
1094<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
1095appropriate nops inserted to ensure restartability.</li>
1096
John Criswellc0c186d2005-11-08 21:11:33 +00001097</ul>
1098</div>
1099
Chris Lattner26299222006-11-18 07:51:14 +00001100<!-- ======================================================================= -->
1101<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +00001102 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +00001103</div>
1104
1105<div class="doc_text">
1106
Chris Lattner3016ee92010-09-29 05:34:42 +00001107<p>The C backend has numerous problems and is not being actively maintained.
1108Depending on it for anything serious is not advised.</p>
1109
Chris Lattner26299222006-11-18 07:51:14 +00001110<ul>
Chris Lattner5733b272008-06-05 06:35:40 +00001111<li><a href="http://llvm.org/PR802">The C backend has only basic support for
1112 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +00001113<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
1114 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif4906abe2009-03-02 12:02:51 +00001115 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +00001116<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands50723a92009-02-25 11:51:54 +00001117<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattner26299222006-11-18 07:51:14 +00001118</ul>
1119
1120</div>
John Criswellc0c186d2005-11-08 21:11:33 +00001121
Misha Brukman500bc302003-11-22 00:38:41 +00001122
1123<!-- ======================================================================= -->
1124<div class="doc_subsection">
Chris Lattner3016ee92010-09-29 05:34:42 +00001125 <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +00001126</div>
Chris Lattner47588f92003-10-02 05:07:23 +00001127
Misha Brukman500bc302003-11-22 00:38:41 +00001128<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +00001129
Chris Lattner3016ee92010-09-29 05:34:42 +00001130<p>llvm-gcc is generally very stable for the C family of languages. The only
1131 major language feature of GCC not supported by llvm-gcc is the
1132 <tt>__builtin_apply</tt> family of builtins. However, some extensions
1133 are only supported on some targets. For example, trampolines are only
1134 supported on some targets (these are used when you take the address of a
1135 nested function).</p>
Misha Brukman500bc302003-11-22 00:38:41 +00001136
Chris Lattner3016ee92010-09-29 05:34:42 +00001137<p>Fortran support generally works, but there are still several unresolved bugs
1138 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
1139 tools/gfortran component for details. Note that llvm-gcc is missing major
1140 Fortran performance work in the frontend and library that went into GCC after
1141 4.2. If you are interested in Fortran, we recommend that you consider using
1142 <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +00001143
Chris Lattner3016ee92010-09-29 05:34:42 +00001144<p>The llvm-gcc 4.2 Ada compiler has basic functionality. However, this is not a
1145mature technology, and problems should be expected. For example:</p>
Chris Lattner2b659ef2008-02-12 06:29:45 +00001146<ul>
Duncan Sands27aff872008-06-08 20:18:35 +00001147<li>The Ada front-end currently only builds on X86-32. This is mainly due
John Criswell524a5dd2009-03-02 15:28:15 +00001148to lack of trampoline support (pointers to nested functions) on other platforms.
1149However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +00001150which does support trampolines.</li>
1151<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
Duncan Sands326a4982009-02-25 11:59:06 +00001152This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
1153exception handling, which is used internally by the compiler.
Chris Lattner61358ab2009-10-13 17:48:04 +00001154Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
Duncan Sands978bcee2008-10-13 17:27:23 +00001155<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
1156and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sands326a4982009-02-25 11:59:06 +00001157(c380004 also fails with gcc-4.2 mainline).
1158If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
1159causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sandsdd3e6722009-03-02 16:35:57 +00001160<li>Some GCC specific Ada tests continue to crash the compiler.</li>
Chris Lattner61358ab2009-10-13 17:48:04 +00001161<li>The <tt>-E</tt> binder option (exception backtraces)
Chris Lattner2b659ef2008-02-12 06:29:45 +00001162<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
Chris Lattner61358ab2009-10-13 17:48:04 +00001163crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +00001164<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
1165or finish at a non-byte offset</a> in a record. Workaround: do not pack records
1166or use representation clauses that result in a field of a non-discrete type
1167starting or finishing in the middle of a byte.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +00001168<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
1169'main' as generated by the Ada binder to be invalid</a>.
1170Workaround: hand edit the file to use pointers for <tt>argv</tt> and
1171<tt>envp</tt> rather than integers.</li>
1172<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
1173ignored</a>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +00001174</ul>
1175</div>
1176
Chris Lattner79c3fe12003-10-02 04:57:28 +00001177<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +00001178<div class="doc_section">
1179 <a name="additionalinfo">Additional Information</a>
1180</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +00001181<!-- *********************************************************************** -->
1182
Misha Brukman500bc302003-11-22 00:38:41 +00001183<div class="doc_text">
1184
Chris Lattner416db102005-05-16 17:13:10 +00001185<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +00001186href="http://llvm.org">LLVM web page</a>, in particular in the <a
1187href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +00001188contains versions of the API documentation which is up-to-date with the
1189Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +00001190You can access versions of these documents specific to this release by going
1191into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +00001192
Misha Brukman500bc302003-11-22 00:38:41 +00001193<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerc463b272005-10-29 07:07:09 +00001194us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +00001195lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +00001196
Misha Brukman500bc302003-11-22 00:38:41 +00001197</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +00001198
1199<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +00001200
Misha Brukman500bc302003-11-22 00:38:41 +00001201<hr>
Misha Brukman2061e892003-11-22 01:23:39 +00001202<address>
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Misha Brukman2061e892003-11-22 01:23:39 +00001207
Chris Lattnerb4b0ce72007-05-18 00:44:29 +00001208 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +00001209 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +00001210</address>
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1213</html>