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Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]7 <title>LLVM 2.9 Release Notes</title>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]8</head>
9<body>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]10
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]11<h1>LLVM 2.9 Release Notes</h1>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]12
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]13<img align=right src="http://llvm.org/img/DragonSmall.png"
Gabor Greif27b166352010-04-22 10:21:43 +0000[diff] [blame]14 width="136" height="136" alt="LLVM Dragon Logo">
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]15
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]16<ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#intro">Introduction</a></li>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]18 <li><a href="#subproj">Sub-project Status Update</a></li>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]19 <li><a href="#externalproj">External Projects Using LLVM 2.9</a></li>
20 <li><a href="#whatsnew">What's New in LLVM 2.9?</a></li>
Chris Lattner77a51732004-04-30 22:17:12 +0000[diff] [blame]21 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Dan Gohmanad888912008-10-14 16:23:02 +0000[diff] [blame]22 <li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]23 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]24</ol>
25
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]26<div class="doc_author">
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]27 <p>Written by the <a href="http://llvm.org/">LLVM Team</a></p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]28</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]29
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]30<!--
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]31<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.9
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]32release.<br>
33You may prefer the
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]34<a href="http://llvm.org/releases/2.8/docs/ReleaseNotes.html">LLVM 2.8
Dan Gohman62af9d22010-05-03 23:51:05 +0000[diff] [blame]35Release Notes</a>.</h1>
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]36 -->
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]37
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]38<!-- *********************************************************************** -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]39<h2>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]40 <a name="intro">Introduction</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]41</h2>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]42<!-- *********************************************************************** -->
43
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]44<div>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]45
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]46<p>This document contains the release notes for the LLVM Compiler
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]47Infrastructure, release 2.9. Here we describe the status of LLVM, including
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]48major improvements from the previous release and significant known problems.
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]49All LLVM releases may be downloaded from the <a
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]50href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]51
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]52<p>For more information about LLVM, including information about the latest
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]53release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattnere7525b52003-10-07 21:38:31 +0000[diff] [blame]54web site</a>. If you have questions or comments, the <a
Chris Lattner0b1c9a52010-03-17 04:41:49 +0000[diff] [blame]55href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's
56Mailing List</a> is a good place to send them.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]57
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]58<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]59main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greif355f81c2008-10-14 11:00:32 +0000[diff] [blame]60current one. To see the release notes for a specific release, please see the
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]61<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]62
63</div>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]64
Chris Lattnerce6b0472011-04-05 23:22:33 +0000[diff] [blame]65<!-- Features that need text if they're finished for 3.1:
66 ARM EHABI
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]67 combiner-aa?
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]68 strong phi elim
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]69 loop dependence analysis
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]70 CorrelatedValuePropagation
Chris Lattnerce6b0472011-04-05 23:22:33 +0000[diff] [blame]71 lib/Transforms/IPO/MergeFunctions.cpp => consider for 3.1.
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]72 -->
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]73
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]74<!-- *********************************************************************** -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]75<h2>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]76 <a name="subproj">Sub-project Status Update</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]77</h2>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]78<!-- *********************************************************************** -->
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]79
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]80<div>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]81<p>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]82The LLVM 2.9 distribution currently consists of code from the core LLVM
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]83repository (which roughly includes the LLVM optimizers, code generators
84and supporting tools), the Clang repository and the llvm-gcc repository. In
85addition to this code, the LLVM Project includes other sub-projects that are in
86development. Here we include updates on these subprojects.
Bill Wendlingf170d2e2009-03-02 04:28:57 +0000[diff] [blame]87</p>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]88
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]89<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]90<h3>
Chris Lattner44c09cd2008-10-13 18:11:54 +0000[diff] [blame]91<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]92</h3>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]93
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]94<div>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]95
Chris Lattner5de7f6e2010-04-26 17:42:18 +0000[diff] [blame]96<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
97C++, and Objective-C languages. Clang aims to provide a better user experience
98through expressive diagnostics, a high level of conformance to language
99standards, fast compilation, and low memory use. Like LLVM, Clang provides a
100modular, library-based architecture that makes it suitable for creating or
101integrating with other development tools. Clang is considered a
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]102production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]103(32- and 64-bit), and for darwin/arm targets.</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]104
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]105<p>In the LLVM 2.9 time-frame, the Clang team has made many improvements in C,
106C++ and Objective-C support. C++ support is now generally rock solid, has
Chris Lattner9d5b3712011-04-06 00:56:12 +0000[diff] [blame]107been exercised on a broad variety of code, and has several new <a
108href="http://clang.llvm.org/cxx_status.html#cxx0x">C++'0x features</a>
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]109implemented (such as rvalue references and variadic templates). LLVM 2.9 has
110also brought in a large range of bug fixes and minor features (e.g. __label__
111support), and is much more compatible with the Linux Kernel.</p>
112
Duncan Sandsce5d9ae2011-04-06 08:07:40 +0000[diff] [blame]113<p>If Clang rejects your code but another compiler accepts it, please take a
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]114look at the <a href="http://clang.llvm.org/compatibility.html">language
Duncan Sandsce5d9ae2011-04-06 08:07:40 +0000[diff] [blame]115compatibility</a> guide to make sure this is not intentional or a known issue.
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]116</p>
Bill Wendlingef362462008-10-27 09:27:33 +0000[diff] [blame]117
Chris Lattner44c09cd2008-10-13 18:11:54 +0000[diff] [blame]118</div>
119
120<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]121<h3>
Duncan Sands1cd78982011-04-04 11:09:08 +0000[diff] [blame]122<a name="dragonegg">DragonEgg: GCC front-ends, LLVM back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]123</h3>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]124
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]125<div>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]126<p>
Duncan Sands1cd78982011-04-04 11:09:08 +0000[diff] [blame]127<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a
128<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin</a> that replaces GCC's
129optimizers and code generators with LLVM's.
130Currently it requires a patched version of gcc-4.5.
131The plugin can target the x86-32 and x86-64 processor families and has been
132used successfully on the Darwin, FreeBSD and Linux platforms.
133The Ada, C, C++ and Fortran languages work well.
134The plugin is capable of compiling plenty of Obj-C, Obj-C++ and Java but it is
135not known whether the compiled code actually works or not!
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]136</p>
137
138<p>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]139The 2.9 release has the following notable changes:
Duncan Sands7f9a0dc2010-09-30 17:37:34 +0000[diff] [blame]140<ul>
Duncan Sands1cd78982011-04-04 11:09:08 +0000[diff] [blame]141<li>The plugin is much more stable when compiling Fortran.</li>
Chris Lattner9d5b3712011-04-06 00:56:12 +0000[diff] [blame]142<li>Inline assembly where an asm output is tied to an input of a different size
143is now supported in many more cases.</li>
Duncan Sands1cd78982011-04-04 11:09:08 +0000[diff] [blame]144<li>Basic support for the __float128 type was added. It is now possible to
145generate LLVM IR from programs using __float128 but code generation does not
146work yet.</li>
147<li>Compiling Java programs no longer systematically crashes the plugin.</li>
Duncan Sands7f9a0dc2010-09-30 17:37:34 +0000[diff] [blame]148</ul>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]149
150</div>
151
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]152<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]153<h3>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]154<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]155</h3>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]156
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]157<div>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]158<p>
159The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
160is a simple library that provides an implementation of the low-level
161target-specific hooks required by code generation and other runtime components.
162For example, when compiling for a 32-bit target, converting a double to a 64-bit
163unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
164function. The compiler-rt library provides highly optimized implementations of
165this and other low-level routines (some are 3x faster than the equivalent
166libgcc routines).</p>
167
Chris Lattner9d5b3712011-04-06 00:56:12 +0000[diff] [blame]168<p>In the LLVM 2.9 timeframe, compiler_rt has had several minor changes for
169 better ARM support, and a fairly major license change. All of the code in the
170 compiler-rt project is now <a href="DeveloperPolicy.html#license">dual
171 licensed</a> under MIT and UIUC license, which allows you to use compiler-rt
172 in applications without the binary copyright reproduction clause. If you
173 prefer the LLVM/UIUC license, you are free to continue using it under that
174 license as well.</p>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]175
176</div>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]177
178<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]179<h3>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]180<a name="lldb">LLDB: Low Level Debugger</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]181</h3>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]182
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]183<div>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]184<p>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]185<a href="http://lldb.llvm.org/">LLDB</a> is a brand new member of the LLVM
186umbrella of projects. LLDB is a next generation, high-performance debugger. It
187is built as a set of reusable components which highly leverage existing
188libraries in the larger LLVM Project, such as the Clang expression parser, the
189LLVM disassembler and the LLVM JIT.</p>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]190
191<p>
Chris Lattner9d5b3712011-04-06 00:56:12 +0000[diff] [blame]192LLDB is has advanced by leaps and bounds in the 2.9 timeframe. It is
193dramatically more stable and useful, and includes both a new <a
194href="http://lldb.llvm.org/tutorial.html">tutorial</a> and a <a
195href="http://lldb.llvm.org/lldb-gdb.html">side-by-side comparison with
196GDB</a>.</p>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]197
198</div>
199
200<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]201<h3>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]202<a name="libc++">libc++: C++ Standard Library</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]203</h3>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]204
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]205<div>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]206<p>
Tobias Grosser436bc5f2010-10-06 21:07:30 +0000[diff] [blame]207<a href="http://libcxx.llvm.org/">libc++</a> is another new member of the LLVM
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]208family. It is an implementation of the C++ standard library, written from the
209ground up to specifically target the forthcoming C++'0X standard and focus on
210delivering great performance.</p>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]211
212<p>
Chris Lattner14a33332011-04-06 00:59:18 +0000[diff] [blame]213In the LLVM 2.9 timeframe, libc++ has had numerous bugs fixed, and is now being
214co-developed with Clang's C++'0x mode.</p>
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]215
Chris Lattner14a33332011-04-06 00:59:18 +0000[diff] [blame]216<p>
217Like compiler_rt, libc++ is now <a href="DeveloperPolicy.html#license">dual
218 licensed</a> under the MIT and UIUC license, allowing it to be used more
219 permissively.
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]220</p>
221
222</div>
223
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]224
Chris Lattnercaefe932011-04-07 03:08:22 +0000[diff] [blame]225<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]226<h3>
Chris Lattnercaefe932011-04-07 03:08:22 +0000[diff] [blame]227<a name="LLBrowse">LLBrowse: IR Browser</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]228</h3>
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]229
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]230<div>
Chris Lattnercaefe932011-04-07 03:08:22 +0000[diff] [blame]231<p>
232<a href="http://llvm.org/svn/llvm-project/llbrowse/trunk/doc/LLBrowse.html">
233 LLBrowse</a> is an interactive viewer for LLVM modules. It can load any LLVM
234 module and displays its contents as an expandable tree view, facilitating an
235 easy way to inspect types, functions, global variables, or metadata nodes. It
236 is fully cross-platform, being based on the popular wxWidgets GUI toolkit.
237</p>
238</div>
239
240<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]241<h3>
Chris Lattnercaefe932011-04-07 03:08:22 +0000[diff] [blame]242<a name="vmkit">VMKit</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]243</h3>
Chris Lattnercaefe932011-04-07 03:08:22 +0000[diff] [blame]244
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]245<div>
Chris Lattnercaefe932011-04-07 03:08:22 +0000[diff] [blame]246<p>The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation
247 of a Java Virtual Machine (Java VM or JVM) that uses LLVM for static and
248 just-in-time compilation. As of LLVM 2.9, VMKit now supports generational
249 garbage collectors. The garbage collectors are provided by the MMTk framework,
250 and VMKit can be configured to use one of the numerous implemented collectors
251 of MMTk.
252</p>
253</div>
254
255
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]256<!--=========================================================================-->
Chris Lattner9ee0b012011-04-05 18:38:45 +0000[diff] [blame]257<!--
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]258<h3>
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]259<a name="klee">KLEE: A Symbolic Execution Virtual Machine</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]260</h3>
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]261
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]262<div>
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]263<p>
264<a href="http://klee.llvm.org/">KLEE</a> is a symbolic execution framework for
265programs in LLVM bitcode form. KLEE tries to symbolically evaluate "all" paths
266through the application and records state transitions that lead to fault
267states. This allows it to construct testcases that lead to faults and can even
268be used to verify some algorithms.
269</p>
270
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]271<p>UPDATE!</p>
Chris Lattner9ee0b012011-04-05 18:38:45 +0000[diff] [blame]272</div>-->
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]273
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]274</div>
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]275
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]276<!-- *********************************************************************** -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]277<h2>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]278 <a name="externalproj">External Open Source Projects Using LLVM 2.9</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]279</h2>
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]280<!-- *********************************************************************** -->
281
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]282<div>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]283
284<p>An exciting aspect of LLVM is that it is used as an enabling technology for
285 a lot of other language and tools projects. This section lists some of the
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]286 projects that have already been updated to work with LLVM 2.9.</p>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]287
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]288<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]289<h3>Crack Programming Language</h3>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]290
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]291<div>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]292<p>
293<a href="http://code.google.com/p/crack-language/">Crack</a> aims to provide the
294ease of development of a scripting language with the performance of a compiled
295language. The language derives concepts from C++, Java and Python, incorporating
296object-oriented programming, operator overloading and strong typing.</p>
297</div>
298
299
300<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]301<h3>TTA-based Codesign Environment (TCE)</h3>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]302
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]303<div>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]304<p>TCE is a toolset for designing application-specific processors (ASP) based on
305the Transport triggered architecture (TTA). The toolset provides a complete
306co-design flow from C/C++ programs down to synthesizable VHDL and parallel
307program binaries. Processor customization points include the register files,
308function units, supported operations, and the interconnection network.</p>
309
310<p>TCE uses Clang and LLVM for C/C++ language support, target independent
311optimizations and also for parts of code generation. It generates new LLVM-based
312code generators "on the fly" for the designed TTA processors and loads them in
313to the compiler backend as runtime libraries to avoid per-target recompilation
314of larger parts of the compiler chain.</p>
315</div>
316
317
318
319<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]320<h3>PinaVM</h3>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]321
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]322<div>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]323<p><a href="http://gitorious.org/pinavm/pages/Home">PinaVM</a> is an open
324source, <a href="http://www.systemc.org/">SystemC</a> front-end. Unlike many
325other front-ends, PinaVM actually executes the elaboration of the
326program analyzed using LLVM's JIT infrastructure. It later enriches the
327bitcode with SystemC-specific information.</p>
328</div>
329
330<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]331<h3>Pure</h3>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]332
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]333<div>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]334<p><a href="http://pure-lang.googlecode.com/">Pure</a> is an
335 algebraic/functional
336 programming language based on term rewriting. Programs are collections
337 of equations which are used to evaluate expressions in a symbolic
338 fashion. The interpreter uses LLVM as a backend to JIT-compile Pure
339 programs to fast native code. Pure offers dynamic typing, eager and lazy
340 evaluation, lexical closures, a hygienic macro system (also based on
341 term rewriting), built-in list and matrix support (including list and
342 matrix comprehensions) and an easy-to-use interface to C and other
343 programming languages (including the ability to load LLVM bitcode
344 modules, and inline C, C++, Fortran and Faust code in Pure programs if
345 the corresponding LLVM-enabled compilers are installed).</p>
346
347<p>Pure version 0.47 has been tested and is known to work with LLVM 2.9
348 (and continues to work with older LLVM releases &gt;= 2.5).</p>
349</div>
350
351<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]352<h3 id="icedtea">IcedTea Java Virtual Machine Implementation</h3>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]353
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]354<div>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]355<p>
356<a href="http://icedtea.classpath.org/wiki/Main_Page">IcedTea</a> provides a
357harness to build OpenJDK using only free software build tools and to provide
358replacements for the not-yet free parts of OpenJDK. One of the extensions that
359IcedTea provides is a new JIT compiler named <a
360href="http://icedtea.classpath.org/wiki/ZeroSharkFaq">Shark</a> which uses LLVM
361to provide native code generation without introducing processor-dependent
362code.
363</p>
364
365<p> OpenJDK 7 b112, IcedTea6 1.9 and IcedTea7 1.13 and later have been tested
366and are known to work with LLVM 2.9 (and continue to work with older LLVM
367releases &gt;= 2.6 as well).</p>
368</div>
369
370<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]371<h3>Glasgow Haskell Compiler (GHC)</h3>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]372
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]373<div>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]374<p>GHC is an open source, state-of-the-art programming suite for Haskell,
375a standard lazy functional programming language. It includes an
376optimizing static compiler generating good code for a variety of
377platforms, together with an interactive system for convenient, quick
378development.</p>
379
380<p>In addition to the existing C and native code generators, GHC 7.0 now
381supports an LLVM code generator. GHC supports LLVM 2.7 and later.</p>
382</div>
383
384<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]385<h3>Polly - Polyhedral optimizations for LLVM</h3>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]386
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]387<div>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]388<p>Polly is a project that aims to provide advanced memory access optimizations
389to better take advantage of SIMD units, cache hierarchies, multiple cores or
390even vector accelerators for LLVM. Built around an abstract mathematical
391description based on Z-polyhedra, it provides the infrastructure to develop
392advanced optimizations in LLVM and to connect complex external optimizers. In
393its first year of existence Polly already provides an exact value-based
394dependency analysis as well as basic SIMD and OpenMP code generation support.
395Furthermore, Polly can use PoCC(Pluto) an advanced optimizer for data-locality
396and parallelism.</p>
397</div>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]398
Chris Lattner958d2992011-04-06 16:14:25 +0000[diff] [blame]399<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]400<h3>Rubinius</h3>
Chris Lattner958d2992011-04-06 16:14:25 +0000[diff] [blame]401
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]402<div>
Chris Lattner958d2992011-04-06 16:14:25 +0000[diff] [blame]403 <p><a href="http://github.com/evanphx/rubinius">Rubinius</a> is an environment
404 for running Ruby code which strives to write as much of the implementation in
405 Ruby as possible. Combined with a bytecode interpreting VM, it uses LLVM to
406 optimize and compile ruby code down to machine code. Techniques such as type
407 feedback, method inlining, and deoptimization are all used to remove dynamism
408 from ruby execution and increase performance.</p>
409</div>
410
411
Chris Lattner5ddaab12011-04-07 03:09:21 +0000[diff] [blame]412<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]413<h3>
Chris Lattner5ddaab12011-04-07 03:09:21 +0000[diff] [blame]414<a name="FAUST">FAUST Real-Time Audio Signal Processing Language</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]415</h3>
Chris Lattnerca7c8962010-10-01 06:34:49 +0000[diff] [blame]416
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]417<div>
Chris Lattner5ddaab12011-04-07 03:09:21 +0000[diff] [blame]418<p>
419<a href="http://faust.grame.fr">FAUST</a> is a compiled language for real-time
420audio signal processing. The name FAUST stands for Functional AUdio STream. Its
421programming model combines two approaches: functional programming and block
422diagram composition. In addition with the C, C++, JAVA output formats, the
423Faust compiler can now generate LLVM bitcode, and works with LLVM 2.7-2.9.</p>
424
425</div>
426
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]427</div>
428
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]429<!-- *********************************************************************** -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]430<h2>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]431 <a name="whatsnew">What's New in LLVM 2.9?</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]432</h2>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]433<!-- *********************************************************************** -->
434
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]435<div>
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]436
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]437<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]438minor improvements. Some of the major improvements and new features are listed
439in this section.
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]440</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]441
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]442<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]443<h3>
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]444<a name="majorfeatures">Major New Features</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]445</h3>
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]446
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]447<div>
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]448
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]449<p>LLVM 2.9 includes several major new capabilities:</p>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]450
451<ul>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]452
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]453<li>Type Based Alias Analysis (TBAA) is now implemented and turned on by default
454 in Clang. This allows substantially better load/store optimization in some
455 cases. TBAA can be disabled by passing -fno-strict-aliasing.
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]456</li>
457
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]458<li>This release has seen a continued focus on quality of debug information.
459 LLVM now generates much higher fidelity debug information, particularly when
460 debugging optimized code.</li>
461
462<li>Inline assembly now supports multiple alternative constraints.</li>
463
464<li>A new backend for the NVIDIA PTX virtual ISA (used to target its GPUs) is
465 under rapid development. It is not generally useful in 2.9, but is making
466 rapid progress.</li>
Chris Lattner9ee0b012011-04-05 18:38:45 +0000[diff] [blame]467
Chris Lattner458e79f2008-02-10 08:18:42 +0000[diff] [blame]468</ul>
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]469
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]470</div>
471
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]472<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]473<h3>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]474<a name="coreimprovements">LLVM IR and Core Improvements</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]475</h3>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]476
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]477<div>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]478<p>LLVM IR has several new features for better support of new targets and that
479expose new optimization opportunities:</p>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]480
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]481<ul>
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]482<li>The <a href="LangRef.html#bitwiseops">udiv, ashr, lshr, and shl</a>
483 instructions now have support exact and nuw/nsw bits to indicate that they
484 don't overflow or shift out bits. This is useful for optimization of <a
485 href="http://llvm.org/PR8862">pointer differences</a> and other cases.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]486
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]487<li>LLVM IR now supports the <a href="LangRef.html#globalvars">unnamed_addr</a>
488 attribute to indicate that constant global variables with identical
489 initializers can be merged. This fixed <a href="http://llvm.org/PR8927">an
490 issue</a> where LLVM would incorrectly merge two globals which were supposed
491 to have distinct addresses.</li>
492
493<li>The new <a href="LangRef.html#fnattrs">hotpatch attribute</a> has been added
494 to allow runtime patching of functions.</li>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]495</ul>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]496
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]497</div>
498
499<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]500<h3>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]501<a name="optimizer">Optimizer Improvements</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]502</h3>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]503
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]504<div>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]505
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]506<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattner25879d72008-10-13 21:50:36 +0000[diff] [blame]507release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]508
509<ul>
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]510<li>Link Time Optimization (LTO) has been improved to use MC for parsing inline
511 assembly and now can build large programs like Firefox 4 on both Mac OS X and
512 Linux.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]513
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]514<li>The new -loop-idiom pass recognizes memset/memcpy loops (and memset_pattern
515 on darwin), turning them into library calls, which are typically better
516 optimized than inline code. If you are building a libc and notice that your
517 memcpy and memset functions are compiled into infinite recursion, please build
518 with -ffreestanding or -fno-builtin to disable this pass.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]519
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]520<li>A new -early-cse pass does a fast pass over functions to fold constants,
521 simplify expressions, perform simple dead store elimination, and perform
522 common subexpression elimination. It does a good job at catching some of the
523 trivial redundancies that exist in unoptimized code, making later passes more
Roman Divacky620f6962011-04-06 19:12:21 +0000[diff] [blame]524 effective.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]525
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]526<li>A new -loop-instsimplify pass is used to clean up loop bodies in the loop
527 optimizer.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]528
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]529<li>The new TargetLibraryInfo interface allows mid-level optimizations to know
530 whether the current target's runtime library has certain functions. For
531 example, the optimizer can now transform integer-only printf calls to call
532 iprintf, allowing reduced code size for embedded C libraries (e.g. newlib).
533</li>
534
535<li>LLVM has a new <a href="WritingAnLLVMPass.html#RegionPass">RegionPass</a>
536 infrastructure for region-based optimizations.</li>
537
538<li>Several optimizer passes have been substantially sped up:
539 GVN is much faster on functions with deep dominator trees and lots of basic
540 blocks. The dominator tree and dominance frontier passes are much faster to
541 compute, and preserved by more passes (so they are computed less often). The
542 -scalar-repl pass is also much faster and doesn't use DominanceFrontier.
543</li>
544
545<li>The Dead Store Elimination pass is more aggressive optimizing stores of
546 different types: e.g. a large store following a small one to the same address.
547 The MemCpyOptimizer pass handles several new forms of memcpy elimination.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]548
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]549<li>LLVM now optimizes various idioms for overflow detection into check of the
550 flag register on various CPUs. For example, we now compile:
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]551
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]552 <pre>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]553 unsigned long t = a+b;
554 if (t &lt; a) ...
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]555 </pre>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]556 into:
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]557 <pre>
558 addq %rdi, %rbx
559 jno LBB0_2
560 </pre>
561</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]562
Chris Lattnerfcc65a72010-10-04 02:42:39 +0000[diff] [blame]563</ul>
564
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]565</div>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]566
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]567<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]568<h3>
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]569<a name="mc">MC Level Improvements</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]570</h3>
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]571
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]572<div>
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]573<p>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]574The LLVM Machine Code (aka MC) subsystem was created to solve a number
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]575of problems in the realm of assembly, disassembly, object file format handling,
576and a number of other related areas that CPU instruction-set level tools work
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]577in.</p>
578
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]579<ul>
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]580<li>ELF MC support has matured enough for the integrated assembler to be turned
581 on by default in Clang on X86-32 and X86-64 ELF systems.</li>
582
583<li>MC supports and CodeGen uses the <tt>.file</tt> and <tt>.loc</tt> directives
584 for producing line number debug info. This produces more compact line
585 tables and easier to read .s files.</li>
586
587<li>MC supports the <tt>.cfi_*</tt> directives for producing DWARF
Rafael Espindola01fb4b02011-03-18 04:07:44 +0000[diff] [blame]588 frame information, but it is still not used by CodeGen by default.</li>
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]589
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]590
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]591<li>The MC assembler now generates much better diagnostics for common errors,
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]592 is much faster at matching instructions, is much more bug-compatible with
593 the GAS assembler, and is now generally useful for a broad range of X86
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]594 assembly.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]595
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]596<li>We now have some basic <a href="CodeGenerator.html#mc">internals
597 documentation</a> for MC.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]598
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]599<li>.td files can now specify assembler aliases directly with the <a
600 href="CodeGenerator.html#na_instparsing">MnemonicAlias and InstAlias</a>
601 tblgen classes.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]602
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]603<li>LLVM now has an experimental format-independent object file manipulation
604 library (lib/Object). It supports both PE/COFF and ELF. The llvm-nm tool has
605 been extended to work with native object files, and the new llvm-objdump tool
606 supports disassembly of object files (but no relocations are displayed yet).
607</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]608
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]609<li>Win32 PE-COFF support in the MC assembler has made a lot of progress in the
610 2.9 timeframe, but is still not generally useful.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]611
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]612</ul>
613
614<p>For more information, please see the <a
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]615href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
616LLVM MC Project Blog Post</a>.
617</p>
618
NAKAMURA Takumi8d89b8e2011-04-05 08:24:22 +0000[diff] [blame]619</div>
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]620
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]621<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]622<h3>
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]623<a name="codegen">Target Independent Code Generator Improvements</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]624</h3>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]625
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]626<div>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]627
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]628<p>We have put a significant amount of work into the code generator
629infrastructure, which allows us to implement more aggressive algorithms and make
630it run faster:</p>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]631
632<ul>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]633<li>The pre-register-allocation (preRA) instruction scheduler models register
634 pressure much more accurately in some cases. This allows the adoption of more
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]635 aggressive scheduling heuristics without causing spills to be generated.
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]636</li>
637
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]638<li>LiveDebugVariables is a new pass that keeps track of debugging information
639 for user variables that are promoted to registers in optimized builds.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]640
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]641<li>The scheduler now models operand latency and pipeline forwarding.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]642
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]643<li>A major register allocator infrastructure rewrite is underway. It is not on
644 by default for 2.9 and you are not advised to use it, but it has made
645 substantial progress in the 2.9 timeframe:
646 <ul>
647 <li>A new -regalloc=basic "basic" register allocator can be used as a simple
648 fallback when debugging. It uses the new infrastructure.</li>
649 <li>New infrastructure is in place for live range splitting. "SplitKit" can
650 break a live interval into smaller pieces while preserving SSA form, and
651 SpillPlacement can help find the best split points. This is a work in
652 progress so the API is changing quickly.</li>
653 <li>The inline spiller has learned to clean up after live range splitting. It
654 can hoist spills out of loops, and it can eliminate redundant spills.</li>
655 <li>Rematerialization works with live range splitting.</li>
656 <li>The new "greedy" register allocator using live range splitting. This will
657 be the default register allocator in the next LLVM release, but it is not
658 turned on by default in 2.9.</li>
659 </ul>
660</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]661</ul>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]662</div>
663
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]664<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]665<h3>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]666<a name="x86">X86-32 and X86-64 Target Improvements</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]667</h3>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]668
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]669<div>
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]670<p>New features and major changes in the X86 target include:
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]671</p>
672
673<ul>
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]674<li>LLVM 2.9 includes a complete reimplementation of the MMX instruction set.
675 The reimplementation uses a new LLVM IR <a
676 href="LangRef.html#t_x86mmx">x86_mmx</a> type to ensure that MMX operations
677 are <em>only</em> generated from source that uses MMX builtin operations. With
Duncan Sandsce5d9ae2011-04-06 08:07:40 +0000[diff] [blame]678 this, random types like &lt;2 x i32&gt; are not turned into MMX operations
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]679 (which can be catastrophic without proper "emms" insertion). Because the X86
680 code generator always generates reliable code, the -disable-mmx flag is now
681 removed.
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]682</li>
683
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]684<li>X86 support for FS/GS relative loads and stores using <a
Jay Foad1a7cc442011-04-06 07:55:30 +0000[diff] [blame]685 href="CodeGenerator.html#x86_memory">address space 256/257</a> works reliably
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]686 now.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]687
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]688<li>LLVM 2.9 generates much better code in several cases by using adc/sbb to
689 avoid generation of conditional move instructions for conditional increment
690 and other idioms.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]691
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]692<li>The X86 backend has adopted a new preRA scheduling mode, "list-ilp", to
693 shorten the height of instruction schedules without inducing register spills.
694</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]695
Jay Foad1a7cc442011-04-06 07:55:30 +0000[diff] [blame]696<li>The MC assembler supports 3dNow! and 3DNowA instructions.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]697
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]698<li>Several bugs have been fixed for Windows x64 code generator.</li>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]699</ul>
700
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]701</div>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]702
703<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]704<h3>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]705<a name="ARM">ARM Target Improvements</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]706</h3>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]707
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]708<div>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]709<p>New features of the ARM target include:
710</p>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]711
712<ul>
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]713<li>The ARM backend now has a fast instruction selector, which dramatically
714 improves -O0 compile times.</li>
715<li>The ARM backend has new tuning for Cortex-A8 and Cortex-A9 CPUs.</li>
716<li>The __builtin_prefetch builtin (and llvm.prefetch intrinsic) is compiled
717 into prefetch instructions instead of being discarded.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]718
719<li> The ARM backend preRA scheduler now models machine resources at cycle
720 granularity. This allows the scheduler to both accurately model
721 instruction latency and avoid overcommitting functional units.</li>
722
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]723<li>Countless ARM microoptimizations have landed in LLVM 2.9.</li>
Bob Wilsone44f2982010-09-13 17:39:35 +0000[diff] [blame]724</ul>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]725</div>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]726
727<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]728<h3>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]729<a name="OtherTS">Other Target Specific Improvements</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]730</h3>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]731
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]732<div>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]733<ul>
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]734<li>MicroBlaze: major updates for aggressive delay slot filler, MC-based
735 assembly printing, assembly instruction parsing, ELF .o file emission, and MC
736 instruction disassembler have landed.</li>
737
738<li>SPARC: Many improvements, including using the Y registers for
739 multiplications and addition of a simple delay slot filler.</li>
740
741<li>PowerPC: The backend has been largely MC'ized and is ready to support
Duncan Sandsce5d9ae2011-04-06 08:07:40 +0000[diff] [blame]742 directly writing out mach-o object files. No one seems interested in finishing
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]743 this final step though.</li>
Bruno Cardoso Lopesa21d4702011-04-08 03:06:22 +0000[diff] [blame]744
745<li>Mips: Improved o32 ABI support, including better varags handling.
746More instructions supported in codegen: madd, msub, rotr, rotrv and clo.
747It also now supports lowering block addresses.</li>
748
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]749</ul>
750</div>
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]751
752<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]753<h3>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]754<a name="changes">Major Changes and Removed Features</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]755</h3>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]756
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]757<div>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]758
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]759<p>If you're already an LLVM user or developer with out-of-tree changes based
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]760on LLVM 2.8, this section lists some "gotchas" that you may run into upgrading
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]761from the previous release.</p>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]762
763<ul>
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]764<li><b>This is the last release to support the llvm-gcc frontend.</b></li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]765
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]766<li>LLVM has a new <a href="CodingStandards.html#ll_naming">naming
767 convention standard</a>, though the codebase hasn't fully adopted it yet.</li>
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]768
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]769<li>The new DIBuilder class provides a simpler interface for front ends to
770 encode debug info in LLVM IR, and has replaced DIFactory.</li>
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]771
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]772<li>LLVM IR and other tools always work on normalized target triples (which have
773 been run through <tt>Triple::normalize</tt>).</li>
774
775<li>The target triple x86_64--mingw64 is obsoleted. Use x86_64--mingw32
776 instead.</li>
777
778<li>The PointerTracking pass has been removed from mainline, and moved to The
779 ClamAV project (its only client).</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]780
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]781<li>The LoopIndexSplit, LiveValues, SimplifyHalfPowrLibCalls, GEPSplitter, and
782 PartialSpecialization passes were removed. They were unmaintained,
Duncan Sandsce5d9ae2011-04-06 08:07:40 +0000[diff] [blame]783 buggy, or deemed to be a bad idea.</li>
Devang Pateldbf83832008-10-14 20:03:43 +0000[diff] [blame]784</ul>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]785
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]786</div>
787
Daniel Dunbarf70898a2010-10-04 20:11:41 +0000[diff] [blame]788<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]789<h3>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]790<a name="api_changes">Internal API Changes</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]791</h3>
Daniel Dunbarf70898a2010-10-04 20:11:41 +0000[diff] [blame]792
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]793<div>
Daniel Dunbarf70898a2010-10-04 20:11:41 +0000[diff] [blame]794
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]795<p>In addition, many APIs have changed in this release. Some of the major
796 LLVM API changes are:</p>
Daniel Dunbarf70898a2010-10-04 20:11:41 +0000[diff] [blame]797
798<ul>
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]799<li>include/llvm/System merged into include/llvm/Support.</li>
800<li>The <a href="http://llvm.org/PR5207">llvm::APInt API</a> was significantly
801 cleaned up.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]802
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]803<li>In the code generator, MVT::Flag was renamed to MVT::Glue to more accurately
804 describe its behavior.</li>
805
806<li>The system_error header from C++0x was added, and is now pervasively used to
807 capture and handle i/o and other errors in LLVM.</li>
808
809<li>The old sys::Path API has been deprecated in favor of the new PathV2 API,
810 which is more efficient and flexible.</li>
Daniel Dunbarf70898a2010-10-04 20:11:41 +0000[diff] [blame]811</ul>
812</div>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]813
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]814</div>
815
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]816<!-- *********************************************************************** -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]817<h2>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]818 <a name="knownproblems">Known Problems</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]819</h2>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]820<!-- *********************************************************************** -->
821
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]822<div>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]823
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]824<p>This section contains significant known problems with the LLVM system,
Chris Lattner2a092392008-11-10 05:40:34 +0000[diff] [blame]825listed by component. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]826href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]827there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]828
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]829<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]830<h3>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]831 <a name="experimental">Experimental features included with this release</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]832</h3>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]833
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]834<div>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]835
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]836<p>The following components of this LLVM release are either untested, known to
837be broken or unreliable, or are in early development. These components should
838not be relied on, and bugs should not be filed against them, but they may be
839useful to some people. In particular, if you would like to work on one of these
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]840components, please contact us on the <a
841href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]842
843<ul>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]844<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, PTX, SystemZ
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]845 and XCore backends are experimental.</li>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]846<li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]847 other than darwin and ELF X86 systems.</li>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]848
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]849</ul>
850
851</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]852
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]853<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]854<h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]855 <a name="x86-be">Known problems with the X86 back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]856</h3>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]857
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]858<div>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]859
860<ul>
Anton Korobeynikov486c7d32008-06-08 10:24:13 +0000[diff] [blame]861 <li>The X86 backend does not yet support
862 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
863 floating point stack</a>. It supports the 'f' and 't' constraints, but not
864 'u'.</li>
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]865 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]866 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]867 argument constructs on X86-64 by lowering them manually.</li>
NAKAMURA Takumi8d89b8e2011-04-05 08:24:22 +0000[diff] [blame]868 <li>Windows x64 (aka Win64) code generator has a few issues.
869 <ul>
870 <li>llvm-gcc cannot build the mingw-w64 runtime currently
871 due to lack of support for the 'u' inline assembly
872 constraint and for X87 floating point inline assembly.</li>
873 <li>On mingw-w64, you will see unresolved symbol <tt>__chkstk</tt>
874 due to <a href="http://llvm.org/bugs/show_bug.cgi?id=8919">Bug 8919</a>.
875 It is fixed in <a href="http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20110321/118499.html">r128206</a>.</li>
876 <li>Miss-aligned MOVDQA might crash your program. It is due to
877 <a href="http://llvm.org/bugs/show_bug.cgi?id=9483">Bug 9483</a>,
878 lack of handling aligned internal globals.</li>
879 </ul>
880 </li>
881
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]882</ul>
883
884</div>
885
886<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]887<h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]888 <a name="ppc-be">Known problems with the PowerPC back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]889</h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]890
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]891<div>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]892
893<ul>
Nicolas Geoffray77d99502007-05-15 09:21:28 +0000[diff] [blame]894<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]895compilation, and lacks support for debug information.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]896</ul>
897
898</div>
899
900<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]901<h3>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]902 <a name="arm-be">Known problems with the ARM back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]903</h3>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]904
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]905<div>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]906
907<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]908<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands47fc0a22007-09-26 15:59:54 +0000[diff] [blame]909processors, thumb programs can crash or produce wrong
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]910results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]911<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]912</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]913</ul>
914
915</div>
916
917<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]918<h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]919 <a name="sparc-be">Known problems with the SPARC back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]920</h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]921
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]922<div>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]923
924<ul>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]925<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]926 support the 64-bit SPARC ABI (-m64).</li>
927</ul>
928
929</div>
930
931<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]932<h3>
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]933 <a name="mips-be">Known problems with the MIPS back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]934</h3>
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]935
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]936<div>
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]937
938<ul>
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]939<li>64-bit MIPS targets are not supported yet.</li>
940</ul>
941
942</div>
943
944<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]945<h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]946 <a name="alpha-be">Known problems with the Alpha back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]947</h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]948
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]949<div>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]950
951<ul>
952
953<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
954appropriate nops inserted to ensure restartability.</li>
955
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]956</ul>
957</div>
958
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]959<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]960<h3>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]961 <a name="c-be">Known problems with the C back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]962</h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]963
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]964<div>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]965
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]966<p>The C backend has numerous problems and is not being actively maintained.
967Depending on it for anything serious is not advised.</p>
968
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]969<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]970<li><a href="http://llvm.org/PR802">The C backend has only basic support for
971 inline assembly code</a>.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000[diff] [blame]972<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
973 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif75b2f762009-03-02 12:02:51 +0000[diff] [blame]974 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandse09506a2008-02-10 13:40:55 +0000[diff] [blame]975<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands3aa36732009-02-25 11:51:54 +0000[diff] [blame]976<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]977</ul>
978
979</div>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]980
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]981
982<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]983<h3>
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]984 <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]985</h3>
Chris Lattner178f3db2003-10-02 05:07:23 +0000[diff] [blame]986
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]987<div>
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]988
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]989<p><b>LLVM 2.9 will be the last release of llvm-gcc.</b></p>
990
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]991<p>llvm-gcc is generally very stable for the C family of languages. The only
992 major language feature of GCC not supported by llvm-gcc is the
993 <tt>__builtin_apply</tt> family of builtins. However, some extensions
994 are only supported on some targets. For example, trampolines are only
995 supported on some targets (these are used when you take the address of a
996 nested function).</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]997
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]998<p>Fortran support generally works, but there are still several unresolved bugs
999 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
1000 tools/gfortran component for details. Note that llvm-gcc is missing major
1001 Fortran performance work in the frontend and library that went into GCC after
1002 4.2. If you are interested in Fortran, we recommend that you consider using
1003 <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1004
Duncan Sandsd63e1c82010-10-04 10:06:56 +0000[diff] [blame]1005<p>The llvm-gcc 4.2 Ada compiler has basic functionality, but is no longer being
1006actively maintained. If you are interested in Ada, we recommend that you
1007consider using <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1008</div>
1009
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]1010</div>
1011
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1012<!-- *********************************************************************** -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]1013<h2>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1014 <a name="additionalinfo">Additional Information</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]1015</h2>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1016<!-- *********************************************************************** -->
1017
NAKAMURA Takumi3ad28282011-04-21 01:52:00 +0000[diff] [blame^]1018<div>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1019
Chris Lattnercb5596d2005-05-16 17:13:10 +0000[diff] [blame]1020<p>A wide variety of additional information is available on the <a
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]1021href="http://llvm.org/">LLVM web page</a>, in particular in the <a
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]1022href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]1023contains versions of the API documentation which is up-to-date with the
1024Subversion version of the source code.
Misha Brukman96158092005-03-30 19:14:24 +0000[diff] [blame]1025You can access versions of these documents specific to this release by going
1026into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1027
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1028<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]1029us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]1030lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1031
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1032</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1033
1034<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1035
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1036<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1037<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000[diff] [blame]1038 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]1039 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1040 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]1041 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1042
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]1043 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1044 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1045</address>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1046
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1047</body>
1048</html>