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Chris Lattnerbe2e1b52011-03-10 07:43:44 +00008 <title>LLVM 2.9 Release Notes</title>
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10<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +000011
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000012<div class="doc_title">LLVM 2.9 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>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000020 <li><a href="#externalproj">External Projects Using LLVM 2.9</a></li>
21 <li><a href="#whatsnew">What's New in LLVM 2.9?</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 Lattnerbe2e1b52011-03-10 07:43:44 +000031<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.9
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000032release.<br>
33You may prefer the
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000034<a href="http://llvm.org/releases/2.8/docs/ReleaseNotes.html">LLVM 2.8
Dan Gohmanb44f6c62010-05-03 23:51:05 +000035Release Notes</a>.</h1>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000036
Chris Lattner79c3fe12003-10-02 04:57:28 +000037<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +000038<div class="doc_section">
39 <a name="intro">Introduction</a>
40</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000041<!-- *********************************************************************** -->
42
Misha Brukman500bc302003-11-22 00:38:41 +000043<div class="doc_text">
44
Chris Lattnerf6662f92008-10-13 17:57:36 +000045<p>This document contains the release notes for the LLVM Compiler
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000046Infrastructure, release 2.9. Here we describe the status of LLVM, including
Chris Lattnerf6662f92008-10-13 17:57:36 +000047major improvements from the previous release and significant known problems.
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +000048All LLVM releases may be downloaded from the <a
Chris Lattnerf6662f92008-10-13 17:57:36 +000049href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +000050
Chris Lattner7506b1d2004-12-07 08:04:13 +000051<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +000052release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +000053web site</a>. If you have questions or comments, the <a
Chris Lattnerc66bfef2010-03-17 04:41:49 +000054href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's
55Mailing List</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +000056
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +000057<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner84977642007-09-21 03:54:09 +000058main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greiffa933f82008-10-14 11:00:32 +000059current one. To see the release notes for a specific release, please see the
Chris Lattner84977642007-09-21 03:54:09 +000060<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +000061
62</div>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000063
Chris Lattner61358ab2009-10-13 17:48:04 +000064<!--
65Almost dead code.
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000066 lib/Transforms/IPO/MergeFunctions.cpp => consider for 3.0.
Chris Lattner61358ab2009-10-13 17:48:04 +000067-->
68
69
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000070<!-- Features that need text if they're finished for 3.0:
Chris Lattner914ce462010-04-22 06:28:20 +000071 combiner-aa?
Chris Lattner61358ab2009-10-13 17:48:04 +000072 strong phi elim
Chris Lattner61358ab2009-10-13 17:48:04 +000073 loop dependence analysis
Chris Lattnere07043c2010-09-29 05:30:03 +000074 CorrelatedValuePropagation
Chris Lattneracce85d2008-02-10 07:46:44 +000075 -->
Chris Lattnere07043c2010-09-29 05:30:03 +000076
Chris Lattner96a445e2008-10-13 18:01:01 +000077<!-- *********************************************************************** -->
78<div class="doc_section">
79 <a name="subproj">Sub-project Status Update</a>
Chris Lattnerea34f642008-06-08 21:34:41 +000080</div>
Chris Lattner96a445e2008-10-13 18:01:01 +000081<!-- *********************************************************************** -->
Chris Lattnerea34f642008-06-08 21:34:41 +000082
83<div class="doc_text">
Chris Lattner8348b472008-06-08 21:58:17 +000084<p>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +000085The LLVM 2.9 distribution currently consists of code from the core LLVM
Chris Lattner61358ab2009-10-13 17:48:04 +000086repository (which roughly includes the LLVM optimizers, code generators
87and supporting tools), the Clang repository and the llvm-gcc repository. In
88addition to this code, the LLVM Project includes other sub-projects that are in
89development. Here we include updates on these subprojects.
Bill Wendling63d8c552009-03-02 04:28:57 +000090</p>
Chris Lattner96a445e2008-10-13 18:01:01 +000091
Chris Lattner8348b472008-06-08 21:58:17 +000092</div>
93
Chris Lattner96a445e2008-10-13 18:01:01 +000094
Chris Lattner8348b472008-06-08 21:58:17 +000095<!--=========================================================================-->
Chris Lattner96a445e2008-10-13 18:01:01 +000096<div class="doc_subsection">
Chris Lattnerfb97b2d2008-10-13 18:11:54 +000097<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattner8348b472008-06-08 21:58:17 +000098</div>
99
100<div class="doc_text">
101
Chris Lattner095539f2010-04-26 17:42:18 +0000102<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
103C++, and Objective-C languages. Clang aims to provide a better user experience
104through expressive diagnostics, a high level of conformance to language
105standards, fast compilation, and low memory use. Like LLVM, Clang provides a
106modular, library-based architecture that makes it suitable for creating or
107integrating with other development tools. Clang is considered a
Chris Lattnere07043c2010-09-29 05:30:03 +0000108production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
109(32- and 64-bit), and for darwin-arm targets.</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000110
Chris Lattner0a6f6d52011-04-05 07:19:28 +0000111<p>In the LLVM 2.9 time-frame, the Clang team has made many improvements in C,
112C++ and Objective-C support. C++ support is now generally rock solid, has
113been exercised on a broad variety of code, and has several new C++'0x features
114implemented (such as rvalue references and variadic templates). LLVM 2.9 has
115also brought in a large range of bug fixes and minor features (e.g. __label__
116support), and is much more compatible with the Linux Kernel.</p>
117
118<p>If Clang rejects your code that is built with another compiler, please take a
119look at the <a href="http://clang.llvm.org/compatibility.html">language
120compatibility</a> guide to make sure the issue isn't intentional or a known
121issue.
122</p>
Bill Wendling741748a2008-10-27 09:27:33 +0000123
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000124<ul>
125</ul>
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000126</div>
127
128<!--=========================================================================-->
129<div class="doc_subsection">
Duncan Sands528a5102011-04-04 11:09:08 +0000130<a name="dragonegg">DragonEgg: GCC front-ends, LLVM back-end</a>
Chris Lattner61358ab2009-10-13 17:48:04 +0000131</div>
132
133<div class="doc_text">
134<p>
Duncan Sands528a5102011-04-04 11:09:08 +0000135<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a
136<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin</a> that replaces GCC's
137optimizers and code generators with LLVM's.
138Currently it requires a patched version of gcc-4.5.
139The plugin can target the x86-32 and x86-64 processor families and has been
140used successfully on the Darwin, FreeBSD and Linux platforms.
141The Ada, C, C++ and Fortran languages work well.
142The plugin is capable of compiling plenty of Obj-C, Obj-C++ and Java but it is
143not known whether the compiled code actually works or not!
Duncan Sands749fd832010-04-02 09:23:15 +0000144</p>
145
146<p>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000147The 2.9 release has the following notable changes:
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000148<ul>
Duncan Sands528a5102011-04-04 11:09:08 +0000149<li>The plugin is much more stable when compiling Fortran.</li>
150<li>Inline asm where an asm output is tied to an input of a different size is
151now supported in many more cases.</li>
152<li>Basic support for the __float128 type was added. It is now possible to
153generate LLVM IR from programs using __float128 but code generation does not
154work yet.</li>
155<li>Compiling Java programs no longer systematically crashes the plugin.</li>
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000156</ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000157
158</div>
159
Chris Lattner75547712010-10-03 23:49:06 +0000160<!--=========================================================================-->
161<div class="doc_subsection">
Chris Lattner75547712010-10-03 23:49:06 +0000162<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
163</div>
164
165<div class="doc_text">
166<p>
167The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
168is a simple library that provides an implementation of the low-level
169target-specific hooks required by code generation and other runtime components.
170For example, when compiling for a 32-bit target, converting a double to a 64-bit
171unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
172function. The compiler-rt library provides highly optimized implementations of
173this and other low-level routines (some are 3x faster than the equivalent
174libgcc routines).</p>
175
176<p>
177All of the code in the compiler-rt project is available under the standard LLVM
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000178License, a "BSD-style" license.
179
Chris Lattner0a6f6d52011-04-05 07:19:28 +0000180compiler_rt is now dual licensed under MIT and UIUC license
181
182Several minor changes for better ARM support.
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000183
184New in LLVM 2.9, UPDATE</p>
Chris Lattner75547712010-10-03 23:49:06 +0000185
186</div>
Chris Lattner61358ab2009-10-13 17:48:04 +0000187
188<!--=========================================================================-->
189<div class="doc_subsection">
Chris Lattnere07043c2010-09-29 05:30:03 +0000190<a name="lldb">LLDB: Low Level Debugger</a>
191</div>
192
193<div class="doc_text">
194<p>
Chris Lattner75547712010-10-03 23:49:06 +0000195<a href="http://lldb.llvm.org/">LLDB</a> is a brand new member of the LLVM
196umbrella of projects. LLDB is a next generation, high-performance debugger. It
197is built as a set of reusable components which highly leverage existing
198libraries in the larger LLVM Project, such as the Clang expression parser, the
199LLVM disassembler and the LLVM JIT.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000200
201<p>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000202LLDB is in early development and not included as part of the LLVM 2.9 release,
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000203
Chris Lattner0a6f6d52011-04-05 07:19:28 +0000204
205
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000206<!--
Chris Lattner75547712010-10-03 23:49:06 +0000207but is mature enough to support basic debugging scenarios on Mac OS X in C,
208Objective-C and C++. We'd really like help extending and expanding LLDB to
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000209support new platforms, new languages, new architectures, and new features.-->
Chris Lattnere07043c2010-09-29 05:30:03 +0000210</p>
211
212</div>
213
214<!--=========================================================================-->
215<div class="doc_subsection">
216<a name="libc++">libc++: C++ Standard Library</a>
217</div>
218
219<div class="doc_text">
220<p>
Tobias Grossercdce44b2010-10-06 21:07:30 +0000221<a href="http://libcxx.llvm.org/">libc++</a> is another new member of the LLVM
Chris Lattner75547712010-10-03 23:49:06 +0000222family. It is an implementation of the C++ standard library, written from the
223ground up to specifically target the forthcoming C++'0X standard and focus on
224delivering great performance.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000225
226<p>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000227As of the LLVM 2.9 release, UPDATE!
228
Chris Lattner0a6f6d52011-04-05 07:19:28 +0000229libc++ is now dual licensed under MIT and UIUC license
230
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000231<!--libc++ is virtually feature complete, but would
Chris Lattner75547712010-10-03 23:49:06 +0000232benefit from more testing and better integration with Clang++. It is also
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000233looking forward to the C++ committee finalizing the C++'0x standard.-->
Chris Lattnere07043c2010-09-29 05:30:03 +0000234</p>
235
236</div>
237
Chris Lattner61358ab2009-10-13 17:48:04 +0000238
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000239
240<!--=========================================================================-->
241<div class="doc_subsection">
242<a name="klee">KLEE: A Symbolic Execution Virtual Machine</a>
243</div>
244
245<div class="doc_text">
246<p>
247<a href="http://klee.llvm.org/">KLEE</a> is a symbolic execution framework for
248programs in LLVM bitcode form. KLEE tries to symbolically evaluate "all" paths
249through the application and records state transitions that lead to fault
250states. This allows it to construct testcases that lead to faults and can even
251be used to verify some algorithms.
252</p>
253
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000254<p>UPDATE!</p>
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000255
256</div>
257
258
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000259<!-- *********************************************************************** -->
260<div class="doc_section">
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000261 <a name="externalproj">External Open Source Projects Using LLVM 2.9</a>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000262</div>
263<!-- *********************************************************************** -->
264
Chris Lattner61358ab2009-10-13 17:48:04 +0000265<div class="doc_text">
266
267<p>An exciting aspect of LLVM is that it is used as an enabling technology for
268 a lot of other language and tools projects. This section lists some of the
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000269 projects that have already been updated to work with LLVM 2.9.</p>
Chris Lattner7c8e7962010-04-26 17:38:10 +0000270</div>
271
Chris Lattner75547712010-10-03 23:49:06 +0000272
273
Chris Lattnere0518442010-10-01 06:34:49 +0000274
Chris Lattner8348b472008-06-08 21:58:17 +0000275<!-- *********************************************************************** -->
276<div class="doc_section">
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000277 <a name="whatsnew">What's New in LLVM 2.9?</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000278</div>
279<!-- *********************************************************************** -->
280
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000281<div class="doc_text">
282
Chris Lattner61358ab2009-10-13 17:48:04 +0000283<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattnerf6662f92008-10-13 17:57:36 +0000284minor improvements. Some of the major improvements and new features are listed
285in this section.
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000286</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000287
Chris Lattner914ce462010-04-22 06:28:20 +0000288</div>
289
290<!--=========================================================================-->
291<div class="doc_subsection">
Chris Lattner252b83d2008-02-06 18:00:06 +0000292<a name="majorfeatures">Major New Features</a>
293</div>
294
295<div class="doc_text">
296
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000297<p>LLVM 2.9 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000298
299<ul>
Chris Lattner0a6f6d52011-04-05 07:19:28 +0000300 last release for llvm-gcc
301TBAA
302Triple::normalize is new, llvm triples are always stored in normalized form internally.
303
304MC Assembler: X86 now generates much better diagnostics for common errors,
305 is much faster at matching instructions, is much more bug-compatible with
306 the GAS assembler, and is now generally useful for a broad range of X86
307 assembly.
308
309New Nvidia PTX backend, not generally useful in 2.9 though.
310
311Much better debug info generated, particularly in optimized code situations.
312
313ARM Fast ISel
314
315ELF MC support
316
317X86: Reimplemented all of MMX to introduce a new LLVM IR x86_mmx type. Now
318 random types like &lt;2 x i32&gt; are not iseld to mmx without emms.
319
320Some basic <a href="CodeGenerator.html#mc">internals documentation</a> for MC.
321
322MC Assembler support for .file and .loc.
323
324
325inline asm multiple alternative constraint support.
326
327LoopIdiom: memset/memcpy formation
328
329
330X86 support for FS/GS relative loads and stores using address space 256/257 are
331 reliable now.
332
333ARM: New code placement pass.
334
335
336PointerTracking has been removed from mainline, moved to ClamAV.
337
338EarlyCSE pass.
339
340
341ARM: Improved code generation for Cortex-A8 and Cortex-A9 CPUs.
342
343Scheduler now models operand latency and pipeline forwarding.
344
345Major regalloc rewrite, not on by default for 2.9.
346MC assembler support for 3dNow! and 3DNowA instructions.
347
348LoopIndexSplit pass was removed, unmaintained.
349
350
351COFF support in the MC assembler has made a lot of progress in the 2.9
352 timeframe, but is still not generally useful. Please see
353 "http://llvm.org/bugs/showdependencytree.cgi?id=9100&amp;hide_resolved=1" for open bugs"?
354
355New <a href="WritingAnLLVMPass.html#RegionPass">RegionPass</a> infrastructure
356 for region-based optimizations.
357
358MicroBlaze: major updates for aggressive delay slot filler, MC-based assembly
359 printing, assembly instruction parsing, ELF .o file emission, and MC
360 instruction disassembler.
Chris Lattner8170c102008-02-10 08:18:42 +0000361</ul>
Chris Lattner0a6f6d52011-04-05 07:19:28 +0000362
363Still todo: [101025-110228]
Chris Lattnerdc910082010-03-17 06:41:58 +0000364
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000365</div>
366
Chris Lattner84977642007-09-21 03:54:09 +0000367<!--=========================================================================-->
368<div class="doc_subsection">
Chris Lattner917cc712009-03-02 02:37:32 +0000369<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000370</div>
371
372<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000373<p>LLVM IR has several new features for better support of new targets and that
374expose new optimization opportunities:</p>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000375
Chris Lattner791f77b2008-06-05 06:25:56 +0000376<ul>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000377</ul>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000378
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000379</div>
380
381<!--=========================================================================-->
382<div class="doc_subsection">
Chris Lattneracce85d2008-02-10 07:46:44 +0000383<a name="optimizer">Optimizer Improvements</a>
384</div>
385
386<div class="doc_text">
387
Chris Lattner61358ab2009-10-13 17:48:04 +0000388<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattnerf3013872008-10-13 21:50:36 +0000389release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000390
391<ul>
Rafael Espindolaa26f36c2011-03-18 04:07:44 +0000392 <li>TBAA.</li>
393 <li>LTO has been improved to use MC for parsing inline asm and now
394 can build large programs like Firefox 4 on both OS X and Linux.</li>
Chris Lattner11b66112010-10-04 02:42:39 +0000395</ul>
396
397<!--
398<p>In addition to these features that are done in 2.8, there is preliminary
399 support in the release for Type Based Alias Analysis
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000400 Preliminary work on TBAA but not usable in 2.8.
401 New CorrelatedValuePropagation pass, not on by default in 2.8 yet.
Chris Lattner11b66112010-10-04 02:42:39 +0000402-->
Chris Lattner917cc712009-03-02 02:37:32 +0000403
Chris Lattner61358ab2009-10-13 17:48:04 +0000404</div>
Chris Lattner917cc712009-03-02 02:37:32 +0000405
Chris Lattner0b832202008-06-08 02:45:07 +0000406<!--=========================================================================-->
407<div class="doc_subsection">
Chris Lattner4ba2b652010-09-30 16:31:33 +0000408<a name="mc">MC Level Improvements</a>
409</div>
410
411<div class="doc_text">
412<p>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000413The LLVM Machine Code (aka MC) subsystem was created to solve a number
Chris Lattner4ba2b652010-09-30 16:31:33 +0000414of problems in the realm of assembly, disassembly, object file format handling,
415and a number of other related areas that CPU instruction-set level tools work
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000416in.</p>
417
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000418<ul>
Rafael Espindolaa26f36c2011-03-18 04:07:44 +0000419 <li>MC is now used by default for ELF systems on x86 and
420 x86-64.</li>
421 <li>MC supports and CodeGen uses the <tt>.loc</tt> directives for
422 producing line number debug info. This produces more compact line
423 tables.</li>
424 <li>MC supports the <tt>.cfi_*</tt> directives for producing DWARF
425 frame information, but it is still not used by CodeGen by default.</li>
426 <li>COFF support?</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000427</ul>
428
429<p>For more information, please see the <a
Chris Lattner4ba2b652010-09-30 16:31:33 +0000430href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
431LLVM MC Project Blog Post</a>.
432</p>
433
Chris Lattner4ba2b652010-09-30 16:31:33 +0000434</div>
435
436
Chris Lattner4ba2b652010-09-30 16:31:33 +0000437<!--=========================================================================-->
438<div class="doc_subsection">
Chris Lattner511433e2009-03-02 03:24:11 +0000439<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner0b832202008-06-08 02:45:07 +0000440</div>
441
442<div class="doc_text">
443
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000444<p>We have put a significant amount of work into the code generator
445infrastructure, which allows us to implement more aggressive algorithms and make
446it run faster:</p>
Chris Lattner0b832202008-06-08 02:45:07 +0000447
448<ul>
Chris Lattner3bdcda12010-10-04 03:58:12 +0000449<!-- SplitKit -->
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000450FastISel for ARM.
Chris Lattner84977642007-09-21 03:54:09 +0000451</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000452</div>
453
Chris Lattner917cc712009-03-02 02:37:32 +0000454<!--=========================================================================-->
455<div class="doc_subsection">
456<a name="x86">X86-32 and X86-64 Target Improvements</a>
457</div>
458
459<div class="doc_text">
Chris Lattner7714c912010-10-04 04:39:25 +0000460<p>New features and major changes in the X86 target include:
Chris Lattner917cc712009-03-02 02:37:32 +0000461</p>
462
463<ul>
Chris Lattner917cc712009-03-02 02:37:32 +0000464</ul>
465
Chris Lattner917cc712009-03-02 02:37:32 +0000466</div>
Chris Lattner84977642007-09-21 03:54:09 +0000467
468<!--=========================================================================-->
469<div class="doc_subsection">
Chris Lattner61358ab2009-10-13 17:48:04 +0000470<a name="ARM">ARM Target Improvements</a>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000471</div>
472
473<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000474<p>New features of the ARM target include:
475</p>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000476
477<ul>
Bob Wilsone8472772010-09-13 17:39:35 +0000478</ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000479</div>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000480
Chris Lattner77d29b12008-06-05 08:02:49 +0000481
482<!--=========================================================================-->
483<div class="doc_subsection">
Chris Lattnerf6662f92008-10-13 17:57:36 +0000484<a name="changes">Major Changes and Removed Features</a>
485</div>
486
487<div class="doc_text">
488
Chris Lattnereeb4da02008-10-13 22:06:31 +0000489<p>If you're already an LLVM user or developer with out-of-tree changes based
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000490on LLVM 2.8, this section lists some "gotchas" that you may run into upgrading
Chris Lattnereeb4da02008-10-13 22:06:31 +0000491from the previous release.</p>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000492
493<ul>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000494</ul>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000495
Chris Lattnerbb117712010-10-04 01:29:06 +0000496
497
Chris Lattnereeb4da02008-10-13 22:06:31 +0000498<p>In addition, many APIs have changed in this release. Some of the major LLVM
499API changes are:</p>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000500<ul>
Devang Patelb34dd132008-10-14 20:03:43 +0000501</ul>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000502
Chris Lattnerf6662f92008-10-13 17:57:36 +0000503</div>
504
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000505<!--=========================================================================-->
506<div class="doc_subsection">
507<a name="devtree_changes">Development Infrastructure Changes</a>
508</div>
509
510<div class="doc_text">
511
512<p>This section lists changes to the LLVM development infrastructure. This
513mostly impacts users who actively work on LLVM or follow development on
514mainline, but may also impact users who leverage the LLVM build infrastructure
515or are interested in LLVM qualification.</p>
516
517<ul>
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000518</ul>
519</div>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000520
Chris Lattner79c3fe12003-10-02 04:57:28 +0000521<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000522<div class="doc_section">
523 <a name="knownproblems">Known Problems</a>
524</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000525<!-- *********************************************************************** -->
526
Misha Brukman500bc302003-11-22 00:38:41 +0000527<div class="doc_text">
528
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000529<p>This section contains significant known problems with the LLVM system,
Chris Lattnere18b32e2008-11-10 05:40:34 +0000530listed by component. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000531href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000532there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000533
Misha Brukman500bc302003-11-22 00:38:41 +0000534</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000535
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000536<!-- ======================================================================= -->
537<div class="doc_subsection">
538 <a name="experimental">Experimental features included with this release</a>
539</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000540
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000541<div class="doc_text">
542
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000543<p>The following components of this LLVM release are either untested, known to
544be broken or unreliable, or are in early development. These components should
545not be relied on, and bugs should not be filed against them, but they may be
546useful to some people. In particular, if you would like to work on one of these
Chris Lattner2b659ef2008-02-12 06:29:45 +0000547components, please contact us on the <a
548href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000549
550<ul>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000551<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, PTX, SystemZ
Chris Lattnerbb117712010-10-04 01:29:06 +0000552 and XCore backends are experimental.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000553<li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000554 other than darwin-i386 and darwin-x86_64. FIXME: Not true on ELF anymore?</li>
555
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000556</ul>
557
558</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000559
Misha Brukman500bc302003-11-22 00:38:41 +0000560<!-- ======================================================================= -->
561<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000562 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000563</div>
564
565<div class="doc_text">
566
567<ul>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000568 <li>The X86 backend does not yet support
569 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
570 floating point stack</a>. It supports the 'f' and 't' constraints, but not
571 'u'.</li>
Duncan Sands47eff2b2008-06-08 19:38:43 +0000572 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswell524a5dd2009-03-02 15:28:15 +0000573 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
Chris Lattner914ce462010-04-22 06:28:20 +0000574 runtime currently due to lack of support for the 'u' inline assembly
575 constraint and for X87 floating point inline assembly.</li>
Dan Gohman8207ba92008-06-08 23:05:11 +0000576 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner914ce462010-04-22 06:28:20 +0000577 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman8207ba92008-06-08 23:05:11 +0000578 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000579</ul>
580
581</div>
582
583<!-- ======================================================================= -->
584<div class="doc_subsection">
585 <a name="ppc-be">Known problems with the PowerPC back-end</a>
586</div>
587
588<div class="doc_text">
589
590<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000591<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000592compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000593</ul>
594
595</div>
596
597<!-- ======================================================================= -->
598<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000599 <a name="arm-be">Known problems with the ARM back-end</a>
600</div>
601
602<div class="doc_text">
603
604<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000605<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000606processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000607results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswell524a5dd2009-03-02 15:28:15 +0000608<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000609</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000610</ul>
611
612</div>
613
614<!-- ======================================================================= -->
615<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000616 <a name="sparc-be">Known problems with the SPARC back-end</a>
617</div>
618
619<div class="doc_text">
620
621<ul>
John Criswell524a5dd2009-03-02 15:28:15 +0000622<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Chris Lattner26299222006-11-18 07:51:14 +0000623 support the 64-bit SPARC ABI (-m64).</li>
624</ul>
625
626</div>
627
628<!-- ======================================================================= -->
629<div class="doc_subsection">
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000630 <a name="mips-be">Known problems with the MIPS back-end</a>
631</div>
632
633<div class="doc_text">
634
635<ul>
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000636<li>64-bit MIPS targets are not supported yet.</li>
637</ul>
638
639</div>
640
641<!-- ======================================================================= -->
642<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000643 <a name="alpha-be">Known problems with the Alpha back-end</a>
644</div>
645
646<div class="doc_text">
647
648<ul>
649
650<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
651appropriate nops inserted to ensure restartability.</li>
652
John Criswellc0c186d2005-11-08 21:11:33 +0000653</ul>
654</div>
655
Chris Lattner26299222006-11-18 07:51:14 +0000656<!-- ======================================================================= -->
657<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000658 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000659</div>
660
661<div class="doc_text">
662
Chris Lattner3016ee92010-09-29 05:34:42 +0000663<p>The C backend has numerous problems and is not being actively maintained.
664Depending on it for anything serious is not advised.</p>
665
Chris Lattner26299222006-11-18 07:51:14 +0000666<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000667<li><a href="http://llvm.org/PR802">The C backend has only basic support for
668 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000669<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
670 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif4906abe2009-03-02 12:02:51 +0000671 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000672<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands50723a92009-02-25 11:51:54 +0000673<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000674</ul>
675
676</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000677
Misha Brukman500bc302003-11-22 00:38:41 +0000678
679<!-- ======================================================================= -->
680<div class="doc_subsection">
Chris Lattner3016ee92010-09-29 05:34:42 +0000681 <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000682</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000683
Misha Brukman500bc302003-11-22 00:38:41 +0000684<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000685
Chris Lattner3016ee92010-09-29 05:34:42 +0000686<p>llvm-gcc is generally very stable for the C family of languages. The only
687 major language feature of GCC not supported by llvm-gcc is the
688 <tt>__builtin_apply</tt> family of builtins. However, some extensions
689 are only supported on some targets. For example, trampolines are only
690 supported on some targets (these are used when you take the address of a
691 nested function).</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000692
Chris Lattner3016ee92010-09-29 05:34:42 +0000693<p>Fortran support generally works, but there are still several unresolved bugs
694 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
695 tools/gfortran component for details. Note that llvm-gcc is missing major
696 Fortran performance work in the frontend and library that went into GCC after
697 4.2. If you are interested in Fortran, we recommend that you consider using
698 <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000699
Duncan Sands3af96332010-10-04 10:06:56 +0000700<p>The llvm-gcc 4.2 Ada compiler has basic functionality, but is no longer being
701actively maintained. If you are interested in Ada, we recommend that you
702consider using <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000703</div>
704
Chris Lattner79c3fe12003-10-02 04:57:28 +0000705<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000706<div class="doc_section">
707 <a name="additionalinfo">Additional Information</a>
708</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000709<!-- *********************************************************************** -->
710
Misha Brukman500bc302003-11-22 00:38:41 +0000711<div class="doc_text">
712
Chris Lattner416db102005-05-16 17:13:10 +0000713<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000714href="http://llvm.org">LLVM web page</a>, in particular in the <a
715href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000716contains versions of the API documentation which is up-to-date with the
717Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000718You can access versions of these documents specific to this release by going
719into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000720
Misha Brukman500bc302003-11-22 00:38:41 +0000721<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerc463b272005-10-29 07:07:09 +0000722us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000723lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000724
Misha Brukman500bc302003-11-22 00:38:41 +0000725</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000726
727<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000728
Misha Brukman500bc302003-11-22 00:38:41 +0000729<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000730<address>
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Misha Brukman2061e892003-11-22 01:23:39 +0000735
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000736 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000737 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000738</address>
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