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gerrit-public.fairphone.software / toolchain / llvm-project / e63da933eba10f5ea5bf39af47a0ded719c2cf5d / . / llvm / docs / ReleaseNotes.html
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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
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]44<div class="doc_text">
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
80<div class="doc_text">
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</div>
90
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]91
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]92<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]93<h3>
Chris Lattner44c09cd2008-10-13 18:11:54 +0000[diff] [blame]94<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]95</h3>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]96
97<div class="doc_text">
98
Chris Lattner5de7f6e2010-04-26 17:42:18 +0000[diff] [blame]99<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
100C++, and Objective-C languages. Clang aims to provide a better user experience
101through expressive diagnostics, a high level of conformance to language
102standards, fast compilation, and low memory use. Like LLVM, Clang provides a
103modular, library-based architecture that makes it suitable for creating or
104integrating with other development tools. Clang is considered a
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]105production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]106(32- and 64-bit), and for darwin/arm targets.</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]107
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]108<p>In the LLVM 2.9 time-frame, the Clang team has made many improvements in C,
109C++ and Objective-C support. C++ support is now generally rock solid, has
Chris Lattner9d5b3712011-04-06 00:56:12 +0000[diff] [blame]110been exercised on a broad variety of code, and has several new <a
111href="http://clang.llvm.org/cxx_status.html#cxx0x">C++'0x features</a>
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]112implemented (such as rvalue references and variadic templates). LLVM 2.9 has
113also brought in a large range of bug fixes and minor features (e.g. __label__
114support), and is much more compatible with the Linux Kernel.</p>
115
Duncan Sandsce5d9ae2011-04-06 08:07:40 +0000[diff] [blame]116<p>If Clang rejects your code but another compiler accepts it, please take a
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]117look at the <a href="http://clang.llvm.org/compatibility.html">language
Duncan Sandsce5d9ae2011-04-06 08:07:40 +0000[diff] [blame]118compatibility</a> guide to make sure this is not intentional or a known issue.
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]119</p>
Bill Wendlingef362462008-10-27 09:27:33 +0000[diff] [blame]120
Chris Lattner44c09cd2008-10-13 18:11:54 +0000[diff] [blame]121</div>
122
123<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]124<h3>
Duncan Sands1cd78982011-04-04 11:09:08 +0000[diff] [blame]125<a name="dragonegg">DragonEgg: GCC front-ends, LLVM back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]126</h3>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]127
128<div class="doc_text">
129<p>
Duncan Sands1cd78982011-04-04 11:09:08 +0000[diff] [blame]130<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a
131<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin</a> that replaces GCC's
132optimizers and code generators with LLVM's.
133Currently it requires a patched version of gcc-4.5.
134The plugin can target the x86-32 and x86-64 processor families and has been
135used successfully on the Darwin, FreeBSD and Linux platforms.
136The Ada, C, C++ and Fortran languages work well.
137The plugin is capable of compiling plenty of Obj-C, Obj-C++ and Java but it is
138not known whether the compiled code actually works or not!
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]139</p>
140
141<p>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]142The 2.9 release has the following notable changes:
Duncan Sands7f9a0dc2010-09-30 17:37:34 +0000[diff] [blame]143<ul>
Duncan Sands1cd78982011-04-04 11:09:08 +0000[diff] [blame]144<li>The plugin is much more stable when compiling Fortran.</li>
Chris Lattner9d5b3712011-04-06 00:56:12 +0000[diff] [blame]145<li>Inline assembly where an asm output is tied to an input of a different size
146is now supported in many more cases.</li>
Duncan Sands1cd78982011-04-04 11:09:08 +0000[diff] [blame]147<li>Basic support for the __float128 type was added. It is now possible to
148generate LLVM IR from programs using __float128 but code generation does not
149work yet.</li>
150<li>Compiling Java programs no longer systematically crashes the plugin.</li>
Duncan Sands7f9a0dc2010-09-30 17:37:34 +0000[diff] [blame]151</ul>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]152
153</div>
154
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]155<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]156<h3>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]157<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]158</h3>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]159
160<div class="doc_text">
161<p>
162The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
163is a simple library that provides an implementation of the low-level
164target-specific hooks required by code generation and other runtime components.
165For example, when compiling for a 32-bit target, converting a double to a 64-bit
166unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
167function. The compiler-rt library provides highly optimized implementations of
168this and other low-level routines (some are 3x faster than the equivalent
169libgcc routines).</p>
170
Chris Lattner9d5b3712011-04-06 00:56:12 +0000[diff] [blame]171<p>In the LLVM 2.9 timeframe, compiler_rt has had several minor changes for
172 better ARM support, and a fairly major license change. All of the code in the
173 compiler-rt project is now <a href="DeveloperPolicy.html#license">dual
174 licensed</a> under MIT and UIUC license, which allows you to use compiler-rt
175 in applications without the binary copyright reproduction clause. If you
176 prefer the LLVM/UIUC license, you are free to continue using it under that
177 license as well.</p>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]178
179</div>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]180
181<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]182<h3>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]183<a name="lldb">LLDB: Low Level Debugger</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]184</h3>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]185
186<div class="doc_text">
187<p>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]188<a href="http://lldb.llvm.org/">LLDB</a> is a brand new member of the LLVM
189umbrella of projects. LLDB is a next generation, high-performance debugger. It
190is built as a set of reusable components which highly leverage existing
191libraries in the larger LLVM Project, such as the Clang expression parser, the
192LLVM disassembler and the LLVM JIT.</p>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]193
194<p>
Chris Lattner9d5b3712011-04-06 00:56:12 +0000[diff] [blame]195LLDB is has advanced by leaps and bounds in the 2.9 timeframe. It is
196dramatically more stable and useful, and includes both a new <a
197href="http://lldb.llvm.org/tutorial.html">tutorial</a> and a <a
198href="http://lldb.llvm.org/lldb-gdb.html">side-by-side comparison with
199GDB</a>.</p>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]200
201</div>
202
203<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]204<h3>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]205<a name="libc++">libc++: C++ Standard Library</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]206</h3>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]207
208<div class="doc_text">
209<p>
Tobias Grosser436bc5f2010-10-06 21:07:30 +0000[diff] [blame]210<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]211family. It is an implementation of the C++ standard library, written from the
212ground up to specifically target the forthcoming C++'0X standard and focus on
213delivering great performance.</p>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]214
215<p>
Chris Lattner14a33332011-04-06 00:59:18 +0000[diff] [blame]216In the LLVM 2.9 timeframe, libc++ has had numerous bugs fixed, and is now being
217co-developed with Clang's C++'0x mode.</p>
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]218
Chris Lattner14a33332011-04-06 00:59:18 +0000[diff] [blame]219<p>
220Like compiler_rt, libc++ is now <a href="DeveloperPolicy.html#license">dual
221 licensed</a> under the MIT and UIUC license, allowing it to be used more
222 permissively.
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]223</p>
224
225</div>
226
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]227
Chris Lattnercaefe932011-04-07 03:08:22 +0000[diff] [blame]228<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]229<h3>
Chris Lattnercaefe932011-04-07 03:08:22 +0000[diff] [blame]230<a name="LLBrowse">LLBrowse: IR Browser</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]231</h3>
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]232
Chris Lattnercaefe932011-04-07 03:08:22 +0000[diff] [blame]233<div class="doc_text">
234<p>
235<a href="http://llvm.org/svn/llvm-project/llbrowse/trunk/doc/LLBrowse.html">
236 LLBrowse</a> is an interactive viewer for LLVM modules. It can load any LLVM
237 module and displays its contents as an expandable tree view, facilitating an
238 easy way to inspect types, functions, global variables, or metadata nodes. It
239 is fully cross-platform, being based on the popular wxWidgets GUI toolkit.
240</p>
241</div>
242
243<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]244<h3>
Chris Lattnercaefe932011-04-07 03:08:22 +0000[diff] [blame]245<a name="vmkit">VMKit</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]246</h3>
Chris Lattnercaefe932011-04-07 03:08:22 +0000[diff] [blame]247
248<div class="doc_text">
249<p>The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation
250 of a Java Virtual Machine (Java VM or JVM) that uses LLVM for static and
251 just-in-time compilation. As of LLVM 2.9, VMKit now supports generational
252 garbage collectors. The garbage collectors are provided by the MMTk framework,
253 and VMKit can be configured to use one of the numerous implemented collectors
254 of MMTk.
255</p>
256</div>
257
258
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]259<!--=========================================================================-->
Chris Lattner9ee0b012011-04-05 18:38:45 +0000[diff] [blame]260<!--
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]261<h3>
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]262<a name="klee">KLEE: A Symbolic Execution Virtual Machine</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]263</h3>
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]264
265<div class="doc_text">
266<p>
267<a href="http://klee.llvm.org/">KLEE</a> is a symbolic execution framework for
268programs in LLVM bitcode form. KLEE tries to symbolically evaluate "all" paths
269through the application and records state transitions that lead to fault
270states. This allows it to construct testcases that lead to faults and can even
271be used to verify some algorithms.
272</p>
273
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]274<p>UPDATE!</p>
Chris Lattner9ee0b012011-04-05 18:38:45 +0000[diff] [blame]275</div>-->
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]276
277
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]278<!-- *********************************************************************** -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]279<h2>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]280 <a name="externalproj">External Open Source Projects Using LLVM 2.9</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]281</h2>
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]282<!-- *********************************************************************** -->
283
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]284<div class="doc_text">
285
286<p>An exciting aspect of LLVM is that it is used as an enabling technology for
287 a lot of other language and tools projects. This section lists some of the
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]288 projects that have already been updated to work with LLVM 2.9.</p>
Chris Lattnerdf85c892010-04-26 17:38:10 +0000[diff] [blame]289</div>
290
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]291
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]292<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]293<h3>Crack Programming Language</h3>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]294
295<div class="doc_text">
296<p>
297<a href="http://code.google.com/p/crack-language/">Crack</a> aims to provide the
298ease of development of a scripting language with the performance of a compiled
299language. The language derives concepts from C++, Java and Python, incorporating
300object-oriented programming, operator overloading and strong typing.</p>
301</div>
302
303
304<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]305<h3>TTA-based Codesign Environment (TCE)</h3>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]306
307<div class="doc_text">
308<p>TCE is a toolset for designing application-specific processors (ASP) based on
309the Transport triggered architecture (TTA). The toolset provides a complete
310co-design flow from C/C++ programs down to synthesizable VHDL and parallel
311program binaries. Processor customization points include the register files,
312function units, supported operations, and the interconnection network.</p>
313
314<p>TCE uses Clang and LLVM for C/C++ language support, target independent
315optimizations and also for parts of code generation. It generates new LLVM-based
316code generators "on the fly" for the designed TTA processors and loads them in
317to the compiler backend as runtime libraries to avoid per-target recompilation
318of larger parts of the compiler chain.</p>
319</div>
320
321
322
323<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]324<h3>PinaVM</h3>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]325
326<div class="doc_text">
327<p><a href="http://gitorious.org/pinavm/pages/Home">PinaVM</a> is an open
328source, <a href="http://www.systemc.org/">SystemC</a> front-end. Unlike many
329other front-ends, PinaVM actually executes the elaboration of the
330program analyzed using LLVM's JIT infrastructure. It later enriches the
331bitcode with SystemC-specific information.</p>
332</div>
333
334<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]335<h3>Pure</h3>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]336
337<div class="doc_text">
338<p><a href="http://pure-lang.googlecode.com/">Pure</a> is an
339 algebraic/functional
340 programming language based on term rewriting. Programs are collections
341 of equations which are used to evaluate expressions in a symbolic
342 fashion. The interpreter uses LLVM as a backend to JIT-compile Pure
343 programs to fast native code. Pure offers dynamic typing, eager and lazy
344 evaluation, lexical closures, a hygienic macro system (also based on
345 term rewriting), built-in list and matrix support (including list and
346 matrix comprehensions) and an easy-to-use interface to C and other
347 programming languages (including the ability to load LLVM bitcode
348 modules, and inline C, C++, Fortran and Faust code in Pure programs if
349 the corresponding LLVM-enabled compilers are installed).</p>
350
351<p>Pure version 0.47 has been tested and is known to work with LLVM 2.9
352 (and continues to work with older LLVM releases &gt;= 2.5).</p>
353</div>
354
355<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]356<h3 id="icedtea">IcedTea Java Virtual Machine Implementation</h3>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]357
358<div class="doc_text">
359<p>
360<a href="http://icedtea.classpath.org/wiki/Main_Page">IcedTea</a> provides a
361harness to build OpenJDK using only free software build tools and to provide
362replacements for the not-yet free parts of OpenJDK. One of the extensions that
363IcedTea provides is a new JIT compiler named <a
364href="http://icedtea.classpath.org/wiki/ZeroSharkFaq">Shark</a> which uses LLVM
365to provide native code generation without introducing processor-dependent
366code.
367</p>
368
369<p> OpenJDK 7 b112, IcedTea6 1.9 and IcedTea7 1.13 and later have been tested
370and are known to work with LLVM 2.9 (and continue to work with older LLVM
371releases &gt;= 2.6 as well).</p>
372</div>
373
374<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]375<h3>Glasgow Haskell Compiler (GHC)</h3>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]376
377<div class="doc_text">
378<p>GHC is an open source, state-of-the-art programming suite for Haskell,
379a standard lazy functional programming language. It includes an
380optimizing static compiler generating good code for a variety of
381platforms, together with an interactive system for convenient, quick
382development.</p>
383
384<p>In addition to the existing C and native code generators, GHC 7.0 now
385supports an LLVM code generator. GHC supports LLVM 2.7 and later.</p>
386</div>
387
388<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]389<h3>Polly - Polyhedral optimizations for LLVM</h3>
Chris Lattnerae6a89a2011-04-06 01:13:49 +0000[diff] [blame]390
391<div class="doc_text">
392<p>Polly is a project that aims to provide advanced memory access optimizations
393to better take advantage of SIMD units, cache hierarchies, multiple cores or
394even vector accelerators for LLVM. Built around an abstract mathematical
395description based on Z-polyhedra, it provides the infrastructure to develop
396advanced optimizations in LLVM and to connect complex external optimizers. In
397its first year of existence Polly already provides an exact value-based
398dependency analysis as well as basic SIMD and OpenMP code generation support.
399Furthermore, Polly can use PoCC(Pluto) an advanced optimizer for data-locality
400and parallelism.</p>
401</div>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]402
Chris Lattner958d2992011-04-06 16:14:25 +0000[diff] [blame]403<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]404<h3>Rubinius</h3>
Chris Lattner958d2992011-04-06 16:14:25 +0000[diff] [blame]405
406<div class="doc_text">
407 <p><a href="http://github.com/evanphx/rubinius">Rubinius</a> is an environment
408 for running Ruby code which strives to write as much of the implementation in
409 Ruby as possible. Combined with a bytecode interpreting VM, it uses LLVM to
410 optimize and compile ruby code down to machine code. Techniques such as type
411 feedback, method inlining, and deoptimization are all used to remove dynamism
412 from ruby execution and increase performance.</p>
413</div>
414
415
Chris Lattner5ddaab12011-04-07 03:09:21 +0000[diff] [blame]416<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]417<h3>
Chris Lattner5ddaab12011-04-07 03:09:21 +0000[diff] [blame]418<a name="FAUST">FAUST Real-Time Audio Signal Processing Language</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]419</h3>
Chris Lattnerca7c8962010-10-01 06:34:49 +0000[diff] [blame]420
Chris Lattner5ddaab12011-04-07 03:09:21 +0000[diff] [blame]421<div class="doc_text">
422<p>
423<a href="http://faust.grame.fr">FAUST</a> is a compiled language for real-time
424audio signal processing. The name FAUST stands for Functional AUdio STream. Its
425programming model combines two approaches: functional programming and block
426diagram composition. In addition with the C, C++, JAVA output formats, the
427Faust compiler can now generate LLVM bitcode, and works with LLVM 2.7-2.9.</p>
428
429</div>
430
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]431<!-- *********************************************************************** -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]432<h2>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]433 <a name="whatsnew">What's New in LLVM 2.9?</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]434</h2>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]435<!-- *********************************************************************** -->
436
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]437<div class="doc_text">
438
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]439<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]440minor improvements. Some of the major improvements and new features are listed
441in this section.
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]442</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]443
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]444</div>
445
446<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]447<h3>
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]448<a name="majorfeatures">Major New Features</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]449</h3>
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]450
451<div class="doc_text">
452
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]453<p>LLVM 2.9 includes several major new capabilities:</p>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]454
455<ul>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]456
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]457<li>Type Based Alias Analysis (TBAA) is now implemented and turned on by default
458 in Clang. This allows substantially better load/store optimization in some
459 cases. TBAA can be disabled by passing -fno-strict-aliasing.
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]460</li>
461
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]462<li>This release has seen a continued focus on quality of debug information.
463 LLVM now generates much higher fidelity debug information, particularly when
464 debugging optimized code.</li>
465
466<li>Inline assembly now supports multiple alternative constraints.</li>
467
468<li>A new backend for the NVIDIA PTX virtual ISA (used to target its GPUs) is
469 under rapid development. It is not generally useful in 2.9, but is making
470 rapid progress.</li>
Chris Lattner9ee0b012011-04-05 18:38:45 +0000[diff] [blame]471
Chris Lattner458e79f2008-02-10 08:18:42 +0000[diff] [blame]472</ul>
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]473
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]474</div>
475
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]476<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]477<h3>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]478<a name="coreimprovements">LLVM IR and Core Improvements</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]479</h3>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]480
481<div class="doc_text">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]482<p>LLVM IR has several new features for better support of new targets and that
483expose new optimization opportunities:</p>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]484
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]485<ul>
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]486<li>The <a href="LangRef.html#bitwiseops">udiv, ashr, lshr, and shl</a>
487 instructions now have support exact and nuw/nsw bits to indicate that they
488 don't overflow or shift out bits. This is useful for optimization of <a
489 href="http://llvm.org/PR8862">pointer differences</a> and other cases.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]490
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]491<li>LLVM IR now supports the <a href="LangRef.html#globalvars">unnamed_addr</a>
492 attribute to indicate that constant global variables with identical
493 initializers can be merged. This fixed <a href="http://llvm.org/PR8927">an
494 issue</a> where LLVM would incorrectly merge two globals which were supposed
495 to have distinct addresses.</li>
496
497<li>The new <a href="LangRef.html#fnattrs">hotpatch attribute</a> has been added
498 to allow runtime patching of functions.</li>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]499</ul>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]500
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]501</div>
502
503<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]504<h3>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]505<a name="optimizer">Optimizer Improvements</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]506</h3>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]507
508<div class="doc_text">
509
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]510<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]511release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]512
513<ul>
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]514<li>Link Time Optimization (LTO) has been improved to use MC for parsing inline
515 assembly and now can build large programs like Firefox 4 on both Mac OS X and
516 Linux.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]517
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]518<li>The new -loop-idiom pass recognizes memset/memcpy loops (and memset_pattern
519 on darwin), turning them into library calls, which are typically better
520 optimized than inline code. If you are building a libc and notice that your
521 memcpy and memset functions are compiled into infinite recursion, please build
522 with -ffreestanding or -fno-builtin to disable this pass.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]523
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]524<li>A new -early-cse pass does a fast pass over functions to fold constants,
525 simplify expressions, perform simple dead store elimination, and perform
526 common subexpression elimination. It does a good job at catching some of the
527 trivial redundancies that exist in unoptimized code, making later passes more
Roman Divacky620f6962011-04-06 19:12:21 +0000[diff] [blame]528 effective.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]529
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]530<li>A new -loop-instsimplify pass is used to clean up loop bodies in the loop
531 optimizer.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]532
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]533<li>The new TargetLibraryInfo interface allows mid-level optimizations to know
534 whether the current target's runtime library has certain functions. For
535 example, the optimizer can now transform integer-only printf calls to call
536 iprintf, allowing reduced code size for embedded C libraries (e.g. newlib).
537</li>
538
539<li>LLVM has a new <a href="WritingAnLLVMPass.html#RegionPass">RegionPass</a>
540 infrastructure for region-based optimizations.</li>
541
542<li>Several optimizer passes have been substantially sped up:
543 GVN is much faster on functions with deep dominator trees and lots of basic
544 blocks. The dominator tree and dominance frontier passes are much faster to
545 compute, and preserved by more passes (so they are computed less often). The
546 -scalar-repl pass is also much faster and doesn't use DominanceFrontier.
547</li>
548
549<li>The Dead Store Elimination pass is more aggressive optimizing stores of
550 different types: e.g. a large store following a small one to the same address.
551 The MemCpyOptimizer pass handles several new forms of memcpy elimination.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]552
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]553<li>LLVM now optimizes various idioms for overflow detection into check of the
554 flag register on various CPUs. For example, we now compile:
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]555
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]556 <pre>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]557 unsigned long t = a+b;
558 if (t &lt; a) ...
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]559 </pre>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]560 into:
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]561 <pre>
562 addq %rdi, %rbx
563 jno LBB0_2
564 </pre>
565</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]566
Chris Lattnerfcc65a72010-10-04 02:42:39 +0000[diff] [blame]567</ul>
568
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]569</div>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]570
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]571<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]572<h3>
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]573<a name="mc">MC Level Improvements</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]574</h3>
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]575
576<div class="doc_text">
577<p>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]578The LLVM Machine Code (aka MC) subsystem was created to solve a number
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]579of problems in the realm of assembly, disassembly, object file format handling,
580and a number of other related areas that CPU instruction-set level tools work
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]581in.</p>
582
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]583<ul>
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]584<li>ELF MC support has matured enough for the integrated assembler to be turned
585 on by default in Clang on X86-32 and X86-64 ELF systems.</li>
586
587<li>MC supports and CodeGen uses the <tt>.file</tt> and <tt>.loc</tt> directives
588 for producing line number debug info. This produces more compact line
589 tables and easier to read .s files.</li>
590
591<li>MC supports the <tt>.cfi_*</tt> directives for producing DWARF
Rafael Espindola01fb4b02011-03-18 04:07:44 +0000[diff] [blame]592 frame information, but it is still not used by CodeGen by default.</li>
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]593
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]594
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]595<li>The MC assembler now generates much better diagnostics for common errors,
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]596 is much faster at matching instructions, is much more bug-compatible with
597 the GAS assembler, and is now generally useful for a broad range of X86
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]598 assembly.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]599
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]600<li>We now have some basic <a href="CodeGenerator.html#mc">internals
601 documentation</a> for MC.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]602
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]603<li>.td files can now specify assembler aliases directly with the <a
604 href="CodeGenerator.html#na_instparsing">MnemonicAlias and InstAlias</a>
605 tblgen classes.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]606
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]607<li>LLVM now has an experimental format-independent object file manipulation
608 library (lib/Object). It supports both PE/COFF and ELF. The llvm-nm tool has
609 been extended to work with native object files, and the new llvm-objdump tool
610 supports disassembly of object files (but no relocations are displayed yet).
611</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]612
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]613<li>Win32 PE-COFF support in the MC assembler has made a lot of progress in the
614 2.9 timeframe, but is still not generally useful.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]615
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]616</ul>
617
618<p>For more information, please see the <a
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]619href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
620LLVM MC Project Blog Post</a>.
621</p>
622
NAKAMURA Takumi8d89b8e2011-04-05 08:24:22 +0000[diff] [blame]623</div>
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]624
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]625<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]626<h3>
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]627<a name="codegen">Target Independent Code Generator Improvements</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]628</h3>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]629
630<div class="doc_text">
631
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]632<p>We have put a significant amount of work into the code generator
633infrastructure, which allows us to implement more aggressive algorithms and make
634it run faster:</p>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]635
636<ul>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]637<li>The pre-register-allocation (preRA) instruction scheduler models register
638 pressure much more accurately in some cases. This allows the adoption of more
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]639 aggressive scheduling heuristics without causing spills to be generated.
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]640</li>
641
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]642<li>LiveDebugVariables is a new pass that keeps track of debugging information
643 for user variables that are promoted to registers in optimized builds.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]644
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]645<li>The scheduler now models operand latency and pipeline forwarding.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]646
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]647<li>A major register allocator infrastructure rewrite is underway. It is not on
648 by default for 2.9 and you are not advised to use it, but it has made
649 substantial progress in the 2.9 timeframe:
650 <ul>
651 <li>A new -regalloc=basic "basic" register allocator can be used as a simple
652 fallback when debugging. It uses the new infrastructure.</li>
653 <li>New infrastructure is in place for live range splitting. "SplitKit" can
654 break a live interval into smaller pieces while preserving SSA form, and
655 SpillPlacement can help find the best split points. This is a work in
656 progress so the API is changing quickly.</li>
657 <li>The inline spiller has learned to clean up after live range splitting. It
658 can hoist spills out of loops, and it can eliminate redundant spills.</li>
659 <li>Rematerialization works with live range splitting.</li>
660 <li>The new "greedy" register allocator using live range splitting. This will
661 be the default register allocator in the next LLVM release, but it is not
662 turned on by default in 2.9.</li>
663 </ul>
664</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]665</ul>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]666</div>
667
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]668<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]669<h3>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]670<a name="x86">X86-32 and X86-64 Target Improvements</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]671</h3>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]672
673<div class="doc_text">
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]674<p>New features and major changes in the X86 target include:
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]675</p>
676
677<ul>
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]678<li>LLVM 2.9 includes a complete reimplementation of the MMX instruction set.
679 The reimplementation uses a new LLVM IR <a
680 href="LangRef.html#t_x86mmx">x86_mmx</a> type to ensure that MMX operations
681 are <em>only</em> generated from source that uses MMX builtin operations. With
Duncan Sandsce5d9ae2011-04-06 08:07:40 +0000[diff] [blame]682 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]683 (which can be catastrophic without proper "emms" insertion). Because the X86
684 code generator always generates reliable code, the -disable-mmx flag is now
685 removed.
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]686</li>
687
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]688<li>X86 support for FS/GS relative loads and stores using <a
Jay Foad1a7cc442011-04-06 07:55:30 +0000[diff] [blame]689 href="CodeGenerator.html#x86_memory">address space 256/257</a> works reliably
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]690 now.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]691
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]692<li>LLVM 2.9 generates much better code in several cases by using adc/sbb to
693 avoid generation of conditional move instructions for conditional increment
694 and other idioms.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]695
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]696<li>The X86 backend has adopted a new preRA scheduling mode, "list-ilp", to
697 shorten the height of instruction schedules without inducing register spills.
698</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]699
Jay Foad1a7cc442011-04-06 07:55:30 +0000[diff] [blame]700<li>The MC assembler supports 3dNow! and 3DNowA instructions.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]701
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]702<li>Several bugs have been fixed for Windows x64 code generator.</li>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]703</ul>
704
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]705</div>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]706
707<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]708<h3>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]709<a name="ARM">ARM Target Improvements</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]710</h3>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]711
712<div class="doc_text">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]713<p>New features of the ARM target include:
714</p>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]715
716<ul>
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]717<li>The ARM backend now has a fast instruction selector, which dramatically
718 improves -O0 compile times.</li>
719<li>The ARM backend has new tuning for Cortex-A8 and Cortex-A9 CPUs.</li>
720<li>The __builtin_prefetch builtin (and llvm.prefetch intrinsic) is compiled
721 into prefetch instructions instead of being discarded.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]722
723<li> The ARM backend preRA scheduler now models machine resources at cycle
724 granularity. This allows the scheduler to both accurately model
725 instruction latency and avoid overcommitting functional units.</li>
726
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]727<li>Countless ARM microoptimizations have landed in LLVM 2.9.</li>
Bob Wilsone44f2982010-09-13 17:39:35 +0000[diff] [blame]728</ul>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]729</div>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]730
731<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]732<h3>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]733<a name="OtherTS">Other Target Specific Improvements</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]734</h3>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]735
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]736<div class="doc_text">
737<ul>
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]738<li>MicroBlaze: major updates for aggressive delay slot filler, MC-based
739 assembly printing, assembly instruction parsing, ELF .o file emission, and MC
740 instruction disassembler have landed.</li>
741
742<li>SPARC: Many improvements, including using the Y registers for
743 multiplications and addition of a simple delay slot filler.</li>
744
745<li>PowerPC: The backend has been largely MC'ized and is ready to support
Duncan Sandsce5d9ae2011-04-06 08:07:40 +0000[diff] [blame]746 directly writing out mach-o object files. No one seems interested in finishing
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]747 this final step though.</li>
Bruno Cardoso Lopesa21d4702011-04-08 03:06:22 +0000[diff] [blame]748
749<li>Mips: Improved o32 ABI support, including better varags handling.
750More instructions supported in codegen: madd, msub, rotr, rotrv and clo.
751It also now supports lowering block addresses.</li>
752
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]753</ul>
754</div>
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]755
756<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]757<h3>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]758<a name="changes">Major Changes and Removed Features</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]759</h3>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]760
761<div class="doc_text">
762
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]763<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]764on LLVM 2.8, this section lists some "gotchas" that you may run into upgrading
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]765from the previous release.</p>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]766
767<ul>
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]768<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]769
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]770<li>LLVM has a new <a href="CodingStandards.html#ll_naming">naming
771 convention standard</a>, though the codebase hasn't fully adopted it yet.</li>
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]772
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]773<li>The new DIBuilder class provides a simpler interface for front ends to
774 encode debug info in LLVM IR, and has replaced DIFactory.</li>
Chris Lattner23e16b592011-04-06 05:50:04 +0000[diff] [blame]775
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]776<li>LLVM IR and other tools always work on normalized target triples (which have
777 been run through <tt>Triple::normalize</tt>).</li>
778
779<li>The target triple x86_64--mingw64 is obsoleted. Use x86_64--mingw32
780 instead.</li>
781
782<li>The PointerTracking pass has been removed from mainline, and moved to The
783 ClamAV project (its only client).</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]784
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]785<li>The LoopIndexSplit, LiveValues, SimplifyHalfPowrLibCalls, GEPSplitter, and
786 PartialSpecialization passes were removed. They were unmaintained,
Duncan Sandsce5d9ae2011-04-06 08:07:40 +0000[diff] [blame]787 buggy, or deemed to be a bad idea.</li>
Devang Pateldbf83832008-10-14 20:03:43 +0000[diff] [blame]788</ul>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]789
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]790</div>
791
Daniel Dunbarf70898a2010-10-04 20:11:41 +0000[diff] [blame]792<!--=========================================================================-->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]793<h3>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]794<a name="api_changes">Internal API Changes</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]795</h3>
Daniel Dunbarf70898a2010-10-04 20:11:41 +0000[diff] [blame]796
797<div class="doc_text">
798
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]799<p>In addition, many APIs have changed in this release. Some of the major
800 LLVM API changes are:</p>
Daniel Dunbarf70898a2010-10-04 20:11:41 +0000[diff] [blame]801
802<ul>
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]803<li>include/llvm/System merged into include/llvm/Support.</li>
804<li>The <a href="http://llvm.org/PR5207">llvm::APInt API</a> was significantly
805 cleaned up.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame]806
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]807<li>In the code generator, MVT::Flag was renamed to MVT::Glue to more accurately
808 describe its behavior.</li>
809
810<li>The system_error header from C++0x was added, and is now pervasively used to
811 capture and handle i/o and other errors in LLVM.</li>
812
813<li>The old sys::Path API has been deprecated in favor of the new PathV2 API,
814 which is more efficient and flexible.</li>
Daniel Dunbarf70898a2010-10-04 20:11:41 +0000[diff] [blame]815</ul>
816</div>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]817
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]818<!-- *********************************************************************** -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]819<h2>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]820 <a name="knownproblems">Known Problems</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]821</h2>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]822<!-- *********************************************************************** -->
823
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]824<div class="doc_text">
825
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]826<p>This section contains significant known problems with the LLVM system,
Chris Lattner2a092392008-11-10 05:40:34 +0000[diff] [blame]827listed by component. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]828href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]829there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]830
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]831</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]832
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]833<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]834<h3>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]835 <a name="experimental">Experimental features included with this release</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]836</h3>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]837
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]838<div class="doc_text">
839
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]840<p>The following components of this LLVM release are either untested, known to
841be broken or unreliable, or are in early development. These components should
842not be relied on, and bugs should not be filed against them, but they may be
843useful 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]844components, please contact us on the <a
845href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]846
847<ul>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]848<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, PTX, SystemZ
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]849 and XCore backends are experimental.</li>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]850<li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]851 other than darwin and ELF X86 systems.</li>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]852
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]853</ul>
854
855</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]856
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]857<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]858<h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]859 <a name="x86-be">Known problems with the X86 back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]860</h3>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]861
862<div class="doc_text">
863
864<ul>
Anton Korobeynikov486c7d32008-06-08 10:24:13 +0000[diff] [blame]865 <li>The X86 backend does not yet support
866 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
867 floating point stack</a>. It supports the 'f' and 't' constraints, but not
868 'u'.</li>
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]869 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]870 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]871 argument constructs on X86-64 by lowering them manually.</li>
NAKAMURA Takumi8d89b8e2011-04-05 08:24:22 +0000[diff] [blame]872 <li>Windows x64 (aka Win64) code generator has a few issues.
873 <ul>
874 <li>llvm-gcc cannot build the mingw-w64 runtime currently
875 due to lack of support for the 'u' inline assembly
876 constraint and for X87 floating point inline assembly.</li>
877 <li>On mingw-w64, you will see unresolved symbol <tt>__chkstk</tt>
878 due to <a href="http://llvm.org/bugs/show_bug.cgi?id=8919">Bug 8919</a>.
879 It is fixed in <a href="http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20110321/118499.html">r128206</a>.</li>
880 <li>Miss-aligned MOVDQA might crash your program. It is due to
881 <a href="http://llvm.org/bugs/show_bug.cgi?id=9483">Bug 9483</a>,
882 lack of handling aligned internal globals.</li>
883 </ul>
884 </li>
885
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]886</ul>
887
888</div>
889
890<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]891<h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]892 <a name="ppc-be">Known problems with the PowerPC back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]893</h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]894
895<div class="doc_text">
896
897<ul>
Nicolas Geoffray77d99502007-05-15 09:21:28 +0000[diff] [blame]898<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]899compilation, and lacks support for debug information.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]900</ul>
901
902</div>
903
904<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]905<h3>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]906 <a name="arm-be">Known problems with the ARM back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]907</h3>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]908
909<div class="doc_text">
910
911<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]912<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands47fc0a22007-09-26 15:59:54 +0000[diff] [blame]913processors, thumb programs can crash or produce wrong
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]914results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]915<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]916</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]917</ul>
918
919</div>
920
921<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]922<h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]923 <a name="sparc-be">Known problems with the SPARC back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]924</h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]925
926<div class="doc_text">
927
928<ul>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]929<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]930 support the 64-bit SPARC ABI (-m64).</li>
931</ul>
932
933</div>
934
935<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]936<h3>
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]937 <a name="mips-be">Known problems with the MIPS back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]938</h3>
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]939
940<div class="doc_text">
941
942<ul>
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]943<li>64-bit MIPS targets are not supported yet.</li>
944</ul>
945
946</div>
947
948<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]949<h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]950 <a name="alpha-be">Known problems with the Alpha back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]951</h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]952
953<div class="doc_text">
954
955<ul>
956
957<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
958appropriate nops inserted to ensure restartability.</li>
959
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]960</ul>
961</div>
962
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]963<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]964<h3>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]965 <a name="c-be">Known problems with the C back-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]966</h3>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]967
968<div class="doc_text">
969
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]970<p>The C backend has numerous problems and is not being actively maintained.
971Depending on it for anything serious is not advised.</p>
972
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]973<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]974<li><a href="http://llvm.org/PR802">The C backend has only basic support for
975 inline assembly code</a>.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000[diff] [blame]976<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
977 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif75b2f762009-03-02 12:02:51 +0000[diff] [blame]978 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandse09506a2008-02-10 13:40:55 +0000[diff] [blame]979<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands3aa36732009-02-25 11:51:54 +0000[diff] [blame]980<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]981</ul>
982
983</div>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]984
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]985
986<!-- ======================================================================= -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]987<h3>
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]988 <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]989</h3>
Chris Lattner178f3db2003-10-02 05:07:23 +0000[diff] [blame]990
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]991<div class="doc_text">
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]992
Chris Lattner17c170a2011-04-06 06:29:50 +0000[diff] [blame]993<p><b>LLVM 2.9 will be the last release of llvm-gcc.</b></p>
994
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]995<p>llvm-gcc is generally very stable for the C family of languages. The only
996 major language feature of GCC not supported by llvm-gcc is the
997 <tt>__builtin_apply</tt> family of builtins. However, some extensions
998 are only supported on some targets. For example, trampolines are only
999 supported on some targets (these are used when you take the address of a
1000 nested function).</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1001
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]1002<p>Fortran support generally works, but there are still several unresolved bugs
1003 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
1004 tools/gfortran component for details. Note that llvm-gcc is missing major
1005 Fortran performance work in the frontend and library that went into GCC after
1006 4.2. If you are interested in Fortran, we recommend that you consider using
1007 <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1008
Duncan Sandsd63e1c82010-10-04 10:06:56 +0000[diff] [blame]1009<p>The llvm-gcc 4.2 Ada compiler has basic functionality, but is no longer being
1010actively maintained. If you are interested in Ada, we recommend that you
1011consider using <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1012</div>
1013
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1014<!-- *********************************************************************** -->
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]1015<h2>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1016 <a name="additionalinfo">Additional Information</a>
NAKAMURA Takumi64835132011-04-18 01:17:51 +0000[diff] [blame]1017</h2>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1018<!-- *********************************************************************** -->
1019
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1020<div class="doc_text">
1021
Chris Lattnercb5596d2005-05-16 17:13:10 +0000[diff] [blame]1022<p>A wide variety of additional information is available on the <a
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]1023href="http://llvm.org/">LLVM web page</a>, in particular in the <a
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]1024href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]1025contains versions of the API documentation which is up-to-date with the
1026Subversion version of the source code.
Misha Brukman96158092005-03-30 19:14:24 +0000[diff] [blame]1027You can access versions of these documents specific to this release by going
1028into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1029
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1030<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]1031us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]1032lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1033
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1034</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1035
1036<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1037
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1038<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1039<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000[diff] [blame]1040 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]1041 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1042 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1044
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]1045 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1046 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1047</address>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1048
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1049</body>
1050</html>