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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / cc966de237b760817653fc3261a1d25d0c72025b / . / docs / ReleaseNotes.html
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Chad Rosiere6291d02011-05-27 22:50:46 +0000[diff] [blame]7 <title>LLVM 3.0 Release Notes</title>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]8</head>
9<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]10
Chad Rosiere6291d02011-05-27 22:50:46 +0000[diff] [blame]11<h1>LLVM 3.0 Release Notes</h1>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]12
Chris Lattner0e464a92010-03-17 04:02:39 +0000[diff] [blame]13<img align=right src="http://llvm.org/img/DragonSmall.png"
Gabor Greifee2187a2010-04-22 10:21:43 +0000[diff] [blame]14 width="136" height="136" alt="LLVM Dragon Logo">
Chris Lattner0e464a92010-03-17 04:02:39 +0000[diff] [blame]15
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]16<ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#intro">Introduction</a></li>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]18 <li><a href="#subproj">Sub-project Status Update</a></li>
Chad Rosiere6291d02011-05-27 22:50:46 +0000[diff] [blame]19 <li><a href="#externalproj">External Projects Using LLVM 3.0</a></li>
20 <li><a href="#whatsnew">What's New in LLVM 3.0?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +0000[diff] [blame]21 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Dan Gohman44aa9212008-10-14 16:23:02 +0000[diff] [blame]22 <li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]23 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]24</ol>
25
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]26<div class="doc_author">
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]27 <p>Written by the <a href="http://llvm.org/">LLVM Team</a></p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]28</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]29
Chris Lattner49123fd2011-04-06 06:29:50 +0000[diff] [blame]30<!--
Chad Rosiere6291d02011-05-27 22:50:46 +0000[diff] [blame]31<h1 style="color:red">These are in-progress notes for the upcoming LLVM 3.0
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]32release.<br>
33You may prefer the
Chad Rosiere6291d02011-05-27 22:50:46 +0000[diff] [blame]34<a href="http://llvm.org/releases/2.9/docs/ReleaseNotes.html">LLVM 2.9
Dan Gohmanb44f6c62010-05-03 23:51:05 +0000[diff] [blame]35Release Notes</a>.</h1>
Chris Lattner49123fd2011-04-06 06:29:50 +0000[diff] [blame]36 -->
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]37
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]38<!-- *********************************************************************** -->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]39<h2>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]40 <a name="intro">Introduction</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]41</h2>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]42<!-- *********************************************************************** -->
43
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]44<div>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]45
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]46<p>This document contains the release notes for the LLVM Compiler
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]47 Infrastructure, release 3.0. Here we describe the status of LLVM, including
Chris Lattner1ab8ce92011-11-27 18:47:37 +0000[diff] [blame]48 major improvements from the previous release, improvements in various
49 subprojects of LLVM, and some of the current users of the code.
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]50 All LLVM releases may be downloaded from
51 the <a href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]52
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]53<p>For more information about LLVM, including information about the latest
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]54 release, please check out the <a href="http://llvm.org/">main LLVM web
55 site</a>. If you have questions or comments,
56 the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM
57 Developer's Mailing List</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]58
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]59<p>Note that if you are reading this file from a Subversion checkout or the main
60 LLVM web page, this document applies to the <i>next</i> release, not the
61 current one. To see the release notes for a specific release, please see the
62 <a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]63
64</div>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]65
66
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]67<!-- *********************************************************************** -->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]68<h2>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]69 <a name="subproj">Sub-project Status Update</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]70</h2>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]71<!-- *********************************************************************** -->
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]72
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]73<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]74
75<p>The LLVM 3.0 distribution currently consists of code from the core LLVM
76 repository (which roughly includes the LLVM optimizers, code generators and
Chris Lattnerc343e312011-11-10 20:15:40 +0000[diff] [blame]77 supporting tools), and the Clang repository. In
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]78 addition to this code, the LLVM Project includes other sub-projects that are
79 in development. Here we include updates on these subprojects.</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]80
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]81<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]82<h3>
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000[diff] [blame]83<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]84</h3>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]85
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]86<div>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]87
Chris Lattner095539f2010-04-26 17:42:18 +0000[diff] [blame]88<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]89 C++, and Objective-C languages. Clang aims to provide a better user
90 experience through expressive diagnostics, a high level of conformance to
91 language standards, fast compilation, and low memory use. Like LLVM, Clang
92 provides a modular, library-based architecture that makes it suitable for
93 creating or integrating with other development tools. Clang is considered a
94 production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
Chris Lattner1ab8ce92011-11-27 18:47:37 +0000[diff] [blame]95 (32- and 64-bit), and for Darwin/ARM targets.</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]96
Chandler Carruthcc966de2011-11-29 00:32:43 +0000[diff] [blame^]97<p>In the LLVM 3.0 time-frame, the Clang team has made many improvements:
Douglas Gregorba087df2011-10-15 00:48:01 +0000[diff] [blame]98<ul>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]99 <li>Greatly improved support for building C++ applications, with greater
100 stability and better diagnostics.</li>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]101
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]102 <li><a href="http://clang.llvm.org/cxx_status.html">Improved support</a> for
103 the <a href="http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=50372">C++
Chris Lattner1ab8ce92011-11-27 18:47:37 +0000[diff] [blame]104 2011</a> standard (aka "C++'0x"), including implementations of non-static data member
105 initializers, alias templates, delegating constructors, range-based
106 for loops, and implicitly-generated move constructors and move assignment
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]107 operators, among others.</li>
Douglas Gregorba087df2011-10-15 00:48:01 +0000[diff] [blame]108
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]109 <li>Implemented support for some features of the upcoming C1x standard,
110 including static assertions and generic selections.</li>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]111
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]112 <li>Better detection of include and linking paths for system headers and
113 libraries, especially for Linux distributions.</li>
Douglas Gregorba087df2011-10-15 00:48:01 +0000[diff] [blame]114
David Chisnall553284e2011-11-26 10:56:17 +0000[diff] [blame]115 <li>Several improvements to Objective-C support, including:
116
117 <ul>
118 <li><a href="http://clang.llvm.org/docs/AutomaticReferenceCounting.html">
119 Automatic Reference Counting</a> (ARC) and an improved memory model
120 cleanly separating object and C memory.</li>
121
Chris Lattner1ab8ce92011-11-27 18:47:37 +0000[diff] [blame]122 <li>A migration tool for moving manual retain/release code to ARC</li>
David Chisnall553284e2011-11-26 10:56:17 +0000[diff] [blame]123
124 <li>Better support for data hiding, allowing instance variables to be
125 declared in implementation contexts or class extensions</li>
Chris Lattner1ab8ce92011-11-27 18:47:37 +0000[diff] [blame]126 <li>Weak linking support for Objective-C classes</li>
David Chisnall553284e2011-11-26 10:56:17 +0000[diff] [blame]127 <li>Improved static type checking by inferring the return type of methods
128 such as +alloc and -init.</li>
129 </ul>
130
Chris Lattner1ab8ce92011-11-27 18:47:37 +0000[diff] [blame]131 Some new Objective-C features require either the Mac OS X 10.7 / iOS 5
132 Objective-C runtime, or version 1.6 or later of the GNUstep Objective-C
133 runtime version.</li>
Douglas Gregorba087df2011-10-15 00:48:01 +0000[diff] [blame]134
Peter Collingbournef7fea722011-11-28 20:04:12 +0000[diff] [blame]135 <li>Improved support for OpenCL C, including the <tt>vec_step</tt> operator,
136 address space qualifiers, improved vector literal support and code
137 generation support for the <a href="#PTX">PTX target</a>.</li>
138
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]139 <li>Implemented a number of optimizations in <tt>libclang</tt>, the Clang C
140 interface, to improve the performance of code completion and the mapping
141 from source locations to abstract syntax tree nodes.</li>
Douglas Gregorba087df2011-10-15 00:48:01 +0000[diff] [blame]142</ul>
Chandler Carruthcc966de2011-11-29 00:32:43 +0000[diff] [blame^]143For more details about the changes to Clang since the 2.9 release, see the
144<a href="http://clang.llvm.org/docs/ReleaseNotes.html">Clang release notes</a>
145</p>
Douglas Gregorba087df2011-10-15 00:48:01 +0000[diff] [blame]146
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]147
Duncan Sandsf3ba7af2011-04-06 08:07:40 +0000[diff] [blame]148<p>If Clang rejects your code but another compiler accepts it, please take a
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]149 look at the <a href="http://clang.llvm.org/compatibility.html">language
150 compatibility</a> guide to make sure this is not intentional or a known
151 issue.</p>
Bill Wendling741748a2008-10-27 09:27:33 +0000[diff] [blame]152
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000[diff] [blame]153</div>
154
155<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]156<h3>
Duncan Sands528a5102011-04-04 11:09:08 +0000[diff] [blame]157<a name="dragonegg">DragonEgg: GCC front-ends, LLVM back-end</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]158</h3>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]159
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]160<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]161<p><a href="http://dragonegg.llvm.org/">DragonEgg</a> is a
162 <a href="http://gcc.gnu.org/wiki/plugins">gcc plugin</a> that replaces GCC's
Duncan Sands77352c92011-11-10 18:44:29 +0000[diff] [blame]163 optimizers and code generators with LLVM's. It works with gcc-4.5 or gcc-4.6,
164 targets the x86-32 and x86-64 processor families, and has been successfully
165 used on the Darwin, FreeBSD, KFreeBSD, Linux and OpenBSD platforms. It fully
166 supports Ada, C, C++ and Fortran. It has partial support for Go, Java, Obj-C
167 and Obj-C++.</p>
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]168
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]169<p>The 3.0 release has the following notable changes:</p>
170
Chris Lattner1ab8ce92011-11-27 18:47:37 +0000[diff] [blame]171 <ul>
Duncan Sands77352c92011-11-10 18:44:29 +0000[diff] [blame]172 <li>GCC version 4.6 is now fully supported.</li>
173
174 <li>Patching and building GCC is no longer required: the plugin should work
175 with your system GCC (version 4.5 or 4.6; on Debian/Ubuntu systems the
176 gcc-4.5-plugin-dev or gcc-4.6-plugin-dev package is also needed).</li>
177
178 <li>The <tt>-fplugin-arg-dragonegg-enable-gcc-optzns</tt> option, which runs
179 GCC's optimizers as well as LLVM's, now works much better. This is the
Chris Lattner1ab8ce92011-11-27 18:47:37 +0000[diff] [blame]180 option to use if you want ultimate performance! It is still experimental
181 though: it may cause the plugin to crash.</li>
Duncan Sands77352c92011-11-10 18:44:29 +0000[diff] [blame]182
183 <li>The type and constant conversion logic has been almost entirely rewritten,
184 fixing a multitude of obscure bugs.</li>
185
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000[diff] [blame]186</ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]187
188</div>
189
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]190<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]191<h3>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]192<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]193</h3>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]194
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]195<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]196
197<p>The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
198 is a simple library that provides an implementation of the low-level
199 target-specific hooks required by code generation and other runtime
200 components. For example, when compiling for a 32-bit target, converting a
201 double to a 64-bit unsigned integer is compiled into a runtime call to the
202 "__fixunsdfdi" function. The compiler-rt library provides highly optimized
203 implementations of this and other low-level routines (some are 3x faster than
204 the equivalent libgcc routines).</p>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]205
Chris Lattner1ab8ce92011-11-27 18:47:37 +0000[diff] [blame]206<p>In the LLVM 3.0 timeframe, the target specific ARM code has converted to
207 "unified" assembly syntax, and several new functions have been added to the
208 library.</p>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]209
210</div>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]211
212<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]213<h3>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]214<a name="lldb">LLDB: Low Level Debugger</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]215</h3>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]216
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]217<div>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]218
Chris Lattner9e896712011-11-27 18:53:41 +0000[diff] [blame]219<p>LLDB is a ground-up implementation of a command line debugger, as well as a
220 debugger API that can be used from other applications. LLDB makes use of the
221 Clang parser to provide high-fidelity expression parsing (particularly for
222 C++) and uses the LLVM JIT for target support.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]223
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]224<p>LLDB has advanced by leaps and bounds in the 3.0 timeframe. It is
225 dramatically more stable and useful, and includes both a
226 new <a href="http://lldb.llvm.org/tutorial.html">tutorial</a> and
227 a <a href="http://lldb.llvm.org/lldb-gdb.html">side-by-side comparison with
228 GDB</a>.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]229
230</div>
231
232<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]233<h3>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]234<a name="libc++">libc++: C++ Standard Library</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]235</h3>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]236
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]237<div>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]238
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]239<p>Like compiler_rt, libc++ is now <a href="DeveloperPolicy.html#license">dual
240 licensed</a> under the MIT and UIUC license, allowing it to be used more
241 permissively.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]242
David Chisnall553284e2011-11-26 10:56:17 +0000[diff] [blame]243<p>Libc++ has been ported to FreeBSD and imported into the base system. It is
244 planned to be the default STL implementation for FreeBSD 10.</p>
245
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]246</div>
247
Chris Lattner3d6a80a2011-04-07 03:08:22 +0000[diff] [blame]248<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]249<h3>
Chris Lattner3d6a80a2011-04-07 03:08:22 +0000[diff] [blame]250<a name="vmkit">VMKit</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]251</h3>
Chris Lattner3d6a80a2011-04-07 03:08:22 +0000[diff] [blame]252
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]253<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]254
Nicolas Geoffray54d5df92011-11-10 23:37:56 +0000[diff] [blame]255 <p>The <a href="http://vmkit.llvm.org/">VMKit project</a> is an
256 implementation of a Java Virtual Machine (Java VM or JVM) that uses LLVM for
257 static and just-in-time compilation.
258
259 <p>In the LLVM 3.0 time-frame, VMKit has had significant improvements on both
260 runtime and startup performance:</p>
261
262 <ul>
263 <li>Precompilation: by compiling ahead of time a small subset of Java's core
264 library, the startup performance have been highly optimized to the point that
265 running a 'Hello World' program takes less than 30 milliseconds.</li>
266
267 <li>Customization: by customizing virtual methods for individual classes,
268 the VM can statically determine the target of a virtual call, and decide to
269 inline it.</li>
270
271 <li>Inlining: the VM does more inlining than it did before, by allowing more
272 bytecode instructions to be inlined, and thanks to customization. It also
273 inlines GC barriers, and object allocations.</li>
274
275 <li>New exception model: the generated code for a method that does not do
276 any try/catch is not penalized anymore by the eventuality of calling a
277 method that throws an exception. Instead, the method that throws the
278 exception jumps directly to the method that could catch it.</li>
279 </ul>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]280
Chris Lattner3d6a80a2011-04-07 03:08:22 +0000[diff] [blame]281</div>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]282
Chris Lattner9e896712011-11-27 18:53:41 +0000[diff] [blame]283
284<!--=========================================================================-->
285<h3>
286<a name="LLBrowse">LLBrowse: IR Browser</a>
287</h3>
288
289<div>
290
291<p><a href="http://llvm.org/svn/llvm-project/llbrowse/trunk/doc/LLBrowse.html">
292 LLBrowse</a> is an interactive viewer for LLVM modules. It can load any LLVM
293 module and displays its contents as an expandable tree view, facilitating an
294 easy way to inspect types, functions, global variables, or metadata nodes. It
295 is fully cross-platform, being based on the popular wxWidgets GUI
296 toolkit.</p>
297
298</div>
299
300
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000[diff] [blame]301<!--=========================================================================-->
Chris Lattner7a8e6c52011-04-05 18:38:45 +0000[diff] [blame]302<!--
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]303<h3>
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000[diff] [blame]304<a name="klee">KLEE: A Symbolic Execution Virtual Machine</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]305</h3>
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000[diff] [blame]306
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]307<div>
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000[diff] [blame]308<p>
309<a href="http://klee.llvm.org/">KLEE</a> is a symbolic execution framework for
310programs in LLVM bitcode form. KLEE tries to symbolically evaluate "all" paths
311through the application and records state transitions that lead to fault
312states. This allows it to construct testcases that lead to faults and can even
313be used to verify some algorithms.
314</p>
315
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]316<p>UPDATE!</p>
Chris Lattner7a8e6c52011-04-05 18:38:45 +0000[diff] [blame]317</div>-->
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000[diff] [blame]318
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]319</div>
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000[diff] [blame]320
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]321<!-- *********************************************************************** -->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]322<h2>
Chad Rosiere6291d02011-05-27 22:50:46 +0000[diff] [blame]323 <a name="externalproj">External Open Source Projects Using LLVM 3.0</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]324</h2>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]325<!-- *********************************************************************** -->
326
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]327<div>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]328
329<p>An exciting aspect of LLVM is that it is used as an enabling technology for
330 a lot of other language and tools projects. This section lists some of the
Chad Rosiere6291d02011-05-27 22:50:46 +0000[diff] [blame]331 projects that have already been updated to work with LLVM 3.0.</p>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]332
Chris Lattner3bfe57e2011-04-06 01:13:49 +0000[diff] [blame]333<!--=========================================================================-->
Bill Wendling7be6bc52011-10-26 00:17:54 +0000[diff] [blame]334<h3>AddressSanitizer</h3>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]335
Bill Wendling7be6bc52011-10-26 00:17:54 +0000[diff] [blame]336<div>
337
338<p><a href="http://code.google.com/p/address-sanitizer/">AddressSanitizer</a>
339 uses compiler instrumentation and a specialized malloc library to find C/C++
340 bugs such as use-after-free and out-of-bound accesses to heap, stack, and
341 globals. The key feature of the tool is speed: the average slowdown
342 introduced by AddressSanitizer is less than 2x.</p>
343
344</div>
345
346<!--=========================================================================-->
Bill Wendling29817ea2011-10-26 00:14:36 +0000[diff] [blame]347<h3>ClamAV</h3>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]348
Bill Wendling29817ea2011-10-26 00:14:36 +0000[diff] [blame]349<div>
Bill Wendlingf2a78332011-10-25 01:01:42 +0000[diff] [blame]350
Bill Wendling29817ea2011-10-26 00:14:36 +0000[diff] [blame]351<p><a href="http://www.clamav.net">Clam AntiVirus</a> is an open source (GPL)
352 anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail
353 gateways.</p>
354
355<p>Since version 0.96 it
356 has <a href="http://vrt-sourcefire.blogspot.com/2010/09/introduction-to-clamavs-low-level.html">bytecode
Chris Lattner4f0fe432011-11-27 19:26:30 +0000[diff] [blame]357 signatures</a> that allow writing detections for complex malware.
358 It uses LLVM's JIT to speed up the execution of bytecode on X86, X86-64,
Bill Wendling29817ea2011-10-26 00:14:36 +0000[diff] [blame]359 PPC32/64, falling back to its own interpreter otherwise. The git version was
360 updated to work with LLVM 3.0.</p>
361
362</div>
363
364<!--=========================================================================-->
Tobias Grosserae5a6fd2011-11-14 09:09:26 +0000[diff] [blame]365<h3>clang_complete for VIM</h3>
366
367<div>
368
369<p><a href="https://github.com/Rip-Rip/clang_complete">clang_complete</a> is a
370 VIM plugin, that provides accurate C/C++ autocompletion using the clang front
371 end. The development version of clang complete, can directly use libclang
372 which can maintain a cache to speed up auto completion.</p>
373
374</div>
375
376<!--=========================================================================-->
Bill Wendling65d1f412011-10-26 18:23:06 +0000[diff] [blame]377<h3>clReflect</h3>
378
379<div>
380
381<p><a href="https://bitbucket.org/dwilliamson/clreflect">clReflect</a> is a C++
382 parser that uses clang/LLVM to derive a light-weight reflection database
383 suitable for use in game development. It comes with a very simple runtime
384 library for loading and querying the database, requiring no external
385 dependencies (including CRT), and an additional utility library for object
386 management and serialisation.</p>
387
388</div>
389
390<!--=========================================================================-->
Bill Wendling63507d12011-10-29 01:10:01 +0000[diff] [blame]391<h3>Cling C++ Interpreter</h3>
392
393<div>
394
395<p><a href="http://cern.ch/cling">Cling</a> is an interactive compiler interface
Chris Lattner4f0fe432011-11-27 19:26:30 +0000[diff] [blame]396 (aka C++ interpreter). It supports C++ and C, and uses LLVM's JIT and the
397 Clang parser. It has a prompt interface, runs source files, calls into shared
Bill Wendling63507d12011-10-29 01:10:01 +0000[diff] [blame]398 libraries, prints the value of expressions, even does runtime lookup of
399 identifiers (dynamic scopes). And it just behaves like one would expect from
400 an interpreter.</p>
401
402</div>
403
404<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]405<h3>Crack Programming Language</h3>
Chris Lattner3bfe57e2011-04-06 01:13:49 +0000[diff] [blame]406
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]407<div>
Bill Wendling55d6e672011-11-03 20:10:01 +0000[diff] [blame]408
409<p><a href="http://code.google.com/p/crack-language/">Crack</a> aims to provide
410 the ease of development of a scripting language with the performance of a
411 compiled language. The language derives concepts from C++, Java and Python,
412 incorporating object-oriented programming, operator overloading and strong
413 typing.</p>
414
Chris Lattner3bfe57e2011-04-06 01:13:49 +0000[diff] [blame]415</div>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]416
Chris Lattner3bfe57e2011-04-06 01:13:49 +0000[diff] [blame]417<!--=========================================================================-->
Bill Wendlingb99486f2011-11-08 05:22:54 +0000[diff] [blame]418<h3>Eero</h3>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]419
Bill Wendlingb99486f2011-11-08 05:22:54 +0000[diff] [blame]420<div>
421
422<p><a href="http://eerolanguage.org/">Eero</a> is a fully
423 header-and-binary-compatible dialect of Objective-C 2.0, implemented with a
424 patched version of the Clang/LLVM compiler. It features a streamlined syntax,
425 Python-like indentation, and new operators, for improved readability and
426 reduced code clutter. It also has new features such as limited forms of
427 operator overloading and namespaces, and strict (type-and-operator-safe)
428 enumerations. It is inspired by languages such as Smalltalk, Python, and
429 Ruby.</p>
430
431</div>
432
433<!--=========================================================================-->
Chris Lattneradb417a2011-11-25 20:28:16 +0000[diff] [blame]434<h3>FAUST Real-Time Audio Signal Processing Language</h3>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]435
Chris Lattneradb417a2011-11-25 20:28:16 +0000[diff] [blame]436<div>
437
438<p><a href="http://faust.grame.fr/">FAUST</a> is a compiled language for
439 real-time audio signal processing. The name FAUST stands for Functional
440 AUdio STream. Its programming model combines two approaches: functional
441 programming and block diagram composition. In addition with the C, C++, Java
442 output formats, the Faust compiler can now generate LLVM bitcode, and works
443 with LLVM 2.7-3.0.
444 </p>
445
446</div>
447
448<!--=========================================================================-->
Bill Wendlingf9778192011-10-26 00:09:55 +0000[diff] [blame]449<h3>Glasgow Haskell Compiler (GHC)</h3>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]450
Bill Wendlingf9778192011-10-26 00:09:55 +0000[diff] [blame]451<div>
452
453<p>GHC is an open source, state-of-the-art programming suite for Haskell, a
454 standard lazy functional programming language. It includes an optimizing
455 static compiler generating good code for a variety of platforms, together
456 with an interactive system for convenient, quick development.</p>
457
458<p>GHC 7.0 and onwards include an LLVM code generator, supporting LLVM 2.8 and
459 later. Since LLVM 2.9, GHC now includes experimental support for the ARM
460 platform with LLVM 3.0.</p>
461
462</div>
463
464<!--=========================================================================-->
Bill Wendlingf62333d2011-10-25 20:35:31 +0000[diff] [blame]465<h3>gwXscript</h3>
466
467<div>
468
469<p><a href="http://botwars.tk/gwscript/">gwXscript</a> is an object oriented,
Bill Wendling7c38de22011-10-26 04:24:15 +0000[diff] [blame]470 aspect oriented programming language which can create both executables (ELF,
Bill Wendlingf62333d2011-10-25 20:35:31 +0000[diff] [blame]471 EXE) and shared libraries (DLL, SO, DYNLIB). The compiler is implemented in
472 its own language and translates scripts into LLVM-IR which can be optimized
473 and translated into native code by the LLVM framework. Source code in
474 gwScript contains definitions that expand the namespaces. So you can build
475 your project and simply 'plug out' features by removing a file. The remaining
476 project does not leave scars since you directly separate concerns by the
477 'template' feature of gwX. It is also possible to add new features to a
478 project by just adding files and without editing the original project. This
479 language is used for example to create games or content management systems
480 that should be extendable.</p>
481
482<p>gwXscript is strongly typed and offers comfort with its native types string,
483 hash and array. You can easily write new libraries in gwXscript or native
484 code. gwXscript is type safe and users should not be able to crash your
485 program or execute malicious code except code that is eating CPU time.</p>
486
487</div>
488
489<!--=========================================================================-->
Bill Wendling50cacc82011-10-26 22:55:18 +0000[diff] [blame]490<h3>include-what-you-use</h3>
491
492<div>
493
494<p><a href="http://code.google.com/p/include-what-you-use">include-what-you-use</a>
495 is a tool to ensure that a file directly <code>#include</code>s
496 all <code>.h</code> files that provide a symbol that the file uses. It also
497 removes superfluous <code>#include</code>s from source files.</p>
498
499</div>
500
501<!--=========================================================================-->
Bill Wendling32dc4d92011-11-07 22:05:17 +0000[diff] [blame]502<h3>ispc: The Intel SPMD Program Compiler</h3>
503
504<div>
505
506<p><a href="http://ispc.github.com">ispc</a> is a compiler for "single program,
507 multiple data" (SPMD) programs. It compiles a C-based SPMD programming
508 language to run on the SIMD units of CPUs; it often delivers 5-6x speedups on
509 a single core of a CPU with an 8-wide SIMD unit compared to serial code,
510 while still providing a clean and easy-to-understand programming model. For
511 an introduction to the language and its performance,
Chris Lattnerc343e312011-11-10 20:15:40 +0000[diff] [blame]512 see <a href="http://ispc.github.com/example.html">the walkthrough</a> of a short
Bill Wendling32dc4d92011-11-07 22:05:17 +0000[diff] [blame]513 example program. ispc is licensed under the BSD license.</p>
514
515</div>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]516
Chris Lattnercc089772011-11-25 20:36:17 +0000[diff] [blame]517<!--=========================================================================-->
518<h3>The Julia Programming Language</h3>
519
520<div>
521
522<p><a href="http://github.com/JuliaLang/julia">Julia</a> is a high-level,
523 high-performance dynamic language for technical
524 computing. It provides a sophisticated compiler, distributed parallel
525 execution, numerical accuracy, and an extensive mathematical function
526 library. The compiler uses type inference to generate fast code
527 without any type declarations, and uses LLVM's optimization passes and
528 JIT compiler. The language is designed around multiple dispatch,
529 giving programs a large degree of flexibility. It is ready for use on many
530 kinds of problems.</p>
531</div>
Bill Wendling32dc4d92011-11-07 22:05:17 +0000[diff] [blame]532
533<!--=========================================================================-->
Bill Wendling57fd8762011-10-26 18:20:54 +0000[diff] [blame]534<h3>LanguageKit and Pragmatic Smalltalk</h3>
535
536<div>
537
538<p><a href="http://etoileos.com/etoile/features/languagekit/">LanguageKit</a> is
539 a framework for implementing dynamic languages sharing an object model with
540 Objective-C. It provides static and JIT compilation using LLVM along with
541 its own interpreter. Pragmatic Smalltalk is a dialect of Smalltalk, built on
542 top of LanguageKit, that interfaces directly with Objective-C, sharing the
543 same object representation and message sending behaviour. These projects are
Benjamin Kramer7c5025b2011-11-25 21:26:00 +0000[diff] [blame]544 developed as part of the &Eacute;toil&eacute; desktop environment.</p>
Bill Wendling57fd8762011-10-26 18:20:54 +0000[diff] [blame]545
546</div>
547
548<!--=========================================================================-->
Bill Wendling03250532011-11-01 04:08:23 +0000[diff] [blame]549<h3>LuaAV</h3>
550
551<div>
552
553<p><a href="http://lua-av.mat.ucsb.edu/blog/">LuaAV</a> is a real-time
554 audiovisual scripting environment based around the Lua language and a
555 collection of libraries for sound, graphics, and other media protocols. LuaAV
556 uses LLVM and Clang to JIT compile efficient user-defined audio synthesis
557 routines specified in a declarative syntax.</p>
558
559</div>
560
561<!--=========================================================================-->
Bill Wendlingd4821b82011-10-26 00:16:17 +0000[diff] [blame]562<h3>Mono</h3>
563
564<div>
565
566<p>An open source, cross-platform implementation of C# and the CLR that is
567 binary compatible with Microsoft.NET. Has an optional, dynamically-loaded
568 LLVM code generation backend in Mini, the JIT compiler.</p>
569
Chris Lattner4f0fe432011-11-27 19:26:30 +0000[diff] [blame]570<p>Note that we use a Git mirror of LLVM <a
571 href="https://github.com/mono/llvm">with some patches</a>.</p>
Bill Wendlingd4821b82011-10-26 00:16:17 +0000[diff] [blame]572
573</div>
574
575<!--=========================================================================-->
Tobias Grosser093cb7e2011-11-14 09:09:23 +0000[diff] [blame]576<h3>Polly</h3>
577
578<div>
579
580<p><a href="http://polly.grosser.es">Polly</a> is an advanced data-locality
581 optimizer and automatic parallelizer. It uses an advanced, mathematical
582 model to calculate detailed data dependency information which it uses to
583 optimize the loop structure of a program. Polly can speed up sequential code
584 by improving memory locality and consequently the cache use. Furthermore,
585 Polly is able to expose different kind of parallelism which it exploits by
586 introducing (basic) OpenMP and SIMD code. A mid-term goal of Polly is to
587 automatically create optimized GPU code.</p>
588
589</div>
590
591<!--=========================================================================-->
Bill Wendlingba226272011-10-25 20:37:45 +0000[diff] [blame]592<h3>Portable OpenCL (pocl)</h3>
593
594<div>
595
596<p>Portable OpenCL is an open source implementation of the OpenCL standard which
597 can be easily adapted for new targets. One of the goals of the project is
598 improving performance portability of OpenCL programs, avoiding the need for
599 target-dependent manual optimizations. A "native" target is included, which
600 allows running OpenCL kernels on the host (CPU).</p>
601
602</div>
603
604<!--=========================================================================-->
Bill Wendling0bad98c2011-10-25 20:39:06 +0000[diff] [blame]605<h3>Pure</h3>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]606
Bill Wendling0bad98c2011-10-25 20:39:06 +0000[diff] [blame]607<div>
608<p><a href="http://pure-lang.googlecode.com/">Pure</a> is an
609 algebraic/functional programming language based on term rewriting. Programs
610 are collections of equations which are used to evaluate expressions in a
611 symbolic fashion. The interpreter uses LLVM as a backend to JIT-compile Pure
612 programs to fast native code. Pure offers dynamic typing, eager and lazy
613 evaluation, lexical closures, a hygienic macro system (also based on term
614 rewriting), built-in list and matrix support (including list and matrix
615 comprehensions) and an easy-to-use interface to C and other programming
616 languages (including the ability to load LLVM bitcode modules, and inline C,
617 C++, Fortran and Faust code in Pure programs if the corresponding LLVM-enabled
618 compilers are installed).</p>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]619
Bill Wendling0bad98c2011-10-25 20:39:06 +0000[diff] [blame]620<p>Pure version 0.48 has been tested and is known to work with LLVM 3.0
621 (and continues to work with older LLVM releases &gt;= 2.5).</p>
622
623</div>
624
625<!--=========================================================================-->
Bill Wendling537d85b2011-10-26 00:12:04 +0000[diff] [blame]626<h3>Renderscript</h3>
627
628<div>
629
630<p><a href="http://developer.android.com/guide/topics/renderscript/index.html">Renderscript</a>
631 is Android's advanced 3D graphics rendering and compute API. It provides a
632 portable C99-based language with extensions to facilitate common use cases
633 for enhancing graphics and thread level parallelism. The Renderscript
634 compiler frontend is based on Clang/LLVM. It emits a portable bitcode format
635 for the actual compiled script code, as well as reflects a Java interface for
636 developers to control the execution of the compiled bitcode. Executable
637 machine code is then generated from this bitcode by an LLVM backend on the
638 device. Renderscript is thus able to provide a mechanism by which Android
639 developers can improve performance of their applications while retaining
640 portability.</p>
641
642</div>
643
644<!--=========================================================================-->
Bill Wendling7d5b6212011-10-25 20:40:26 +0000[diff] [blame]645<h3>SAFECode</h3>
646
647<div>
648
649<p><a href="http://safecode.cs.illinois.edu">SAFECode</a> is a memory safe C/C++
650 compiler built using LLVM. It takes standard, unannotated C/C++ code,
651 analyzes the code to ensure that memory accesses and array indexing
652 operations are safe, and instruments the code with run-time checks when
653 safety cannot be proven statically. SAFECode can be used as a debugging aid
654 (like Valgrind) to find and repair memory safety bugs. It can also be used
655 to protect code from security attacks at run-time.</p>
656
657</div>
658
659<!--=========================================================================-->
Bill Wendling02b77b72011-10-26 07:38:19 +0000[diff] [blame]660<h3>The Stupid D Compiler (SDC)</h3>
661
662<div>
663
664<p><a href="https://github.com/bhelyer/SDC">The Stupid D Compiler</a> is a
665 project seeking to write a self-hosting compiler for the D programming
666 language without using the frontend of the reference compiler (DMD).</p>
667
668</div>
669
670<!--=========================================================================-->
Bill Wendling2d7b4af2011-10-25 20:24:32 +0000[diff] [blame]671<h3>TTA-based Co-design Environment (TCE)</h3>
672
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]673<div>
Bill Wendling2d7b4af2011-10-25 20:24:32 +0000[diff] [blame]674
Chris Lattner3bfe57e2011-04-06 01:13:49 +0000[diff] [blame]675<p>TCE is a toolset for designing application-specific processors (ASP) based on
Bill Wendling2d7b4af2011-10-25 20:24:32 +0000[diff] [blame]676 the Transport triggered architecture (TTA). The toolset provides a complete
677 co-design flow from C/C++ programs down to synthesizable VHDL and parallel
678 program binaries. Processor customization points include the register files,
679 function units, supported operations, and the interconnection network.</p>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]680
Chris Lattner3bfe57e2011-04-06 01:13:49 +0000[diff] [blame]681<p>TCE uses Clang and LLVM for C/C++ language support, target independent
Bill Wendling2d7b4af2011-10-25 20:24:32 +0000[diff] [blame]682 optimizations and also for parts of code generation. It generates new
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]683 LLVM-based code generators "on the fly" for the designed TTA processors and
684 loads them in to the compiler backend as runtime libraries to avoid
Bill Wendling2d7b4af2011-10-25 20:24:32 +0000[diff] [blame]685 per-target recompilation of larger parts of the compiler chain.</p>
Chris Lattner3bfe57e2011-04-06 01:13:49 +0000[diff] [blame]686
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]687</div>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]688
Chris Lattner3bfe57e2011-04-06 01:13:49 +0000[diff] [blame]689<!--=========================================================================-->
Bill Wendling628c2662011-10-25 20:27:37 +0000[diff] [blame]690<h3>Tart Programming Language</h3>
691
692<div>
693
694<p><a href="http://code.google.com/p/tart/">Tart</a> is a general-purpose,
695 strongly typed programming language designed for application
696 developers. Strongly inspired by Python and C#, Tart focuses on practical
697 solutions for the professional software developer, while avoiding the clutter
698 and boilerplate of legacy languages like Java and C++. Although Tart is still
699 in development, the current implementation supports many features expected of
700 a modern programming language, such as garbage collection, powerful
701 bidirectional type inference, a greatly simplified syntax for template
702 metaprogramming, closures and function literals, reflection, operator
703 overloading, explicit mutability and immutability, and much more. Tart is
704 flexible enough to accommodate a broad range of programming styles and
705 philosophies, while maintaining a strong commitment to simplicity, minimalism
706 and elegance in design.</p>
707
708</div>
709
710<!--=========================================================================-->
Bill Wendling644ce532011-10-26 09:25:01 +0000[diff] [blame]711<h3>ThreadSanitizer</h3>
712
713<div>
714
715<p><a href="http://code.google.com/p/data-race-test/">ThreadSanitizer</a> is a
716 data race detector for (mostly) C and C++ code, available for Linux, Mac OS
717 and Windows. On different systems, we use binary instrumentation frameworks
Bill Wendlingae8538e2011-10-29 01:11:15 +0000[diff] [blame]718 (Valgrind and Pin) as frontends that generate the program events for the race
719 detection algorithm. On Linux, there's an option of using LLVM-based
720 compile-time instrumentation.</p>
Bill Wendling644ce532011-10-26 09:25:01 +0000[diff] [blame]721
722</div>
723
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]724</div>
725
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]726<!-- *********************************************************************** -->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]727<h2>
Chad Rosiere6291d02011-05-27 22:50:46 +0000[diff] [blame]728 <a name="whatsnew">What's New in LLVM 3.0?</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]729</h2>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]730<!-- *********************************************************************** -->
731
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]732<div>
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]733
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]734<p>This release includes a huge number of bug fixes, performance tweaks and
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]735 minor improvements. Some of the major improvements and new features are
736 listed in this section.</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]737
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]738<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]739<h3>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]740<a name="majorfeatures">Major New Features</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]741</h3>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]742
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]743<div>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]744
Chris Lattner1ab8ce92011-11-27 18:47:37 +0000[diff] [blame]745 <!-- Features that need text if they're finished for 3.1:
746 ARM EHABI
747 combiner-aa?
748 strong phi elim
749 loop dependence analysis
750 CorrelatedValuePropagation
751 lib/Transforms/IPO/MergeFunctions.cpp => consider for 3.1.
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]752 Integrated assembler on by default for arm/thumb?
753
Chris Lattner1ab8ce92011-11-27 18:47:37 +0000[diff] [blame]754 -->
755
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]756 <!-- Near dead:
Chris Lattnerdec23b62011-11-15 22:13:27 +0000[diff] [blame]757 Analysis/RegionInfo.h + Dom Frontiers
758 SparseBitVector: used in LiveVar.
Chris Lattner5a1731d2011-11-27 08:32:32 +0000[diff] [blame]759 llvm/lib/Archive - replace with lib object?
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]760 -->
Chris Lattner6a007d12011-11-25 20:33:27 +0000[diff] [blame]761
Chris Lattner064caf92011-11-27 21:30:28 +0000[diff] [blame]762<p>LLVM 3.0 includes several major changes and big features:</p>
Bill Wendlingbc5f6dd2011-10-26 18:33:01 +0000[diff] [blame]763
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]764<ul>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]765<li>llvm-gcc is no longer supported, and not included in the release. We
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]766 recommend switching to <a
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]767 href="http://clang.llvm.org/">Clang</a> or <a
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]768 href="http://dragonegg.llvm.org/">DragonEgg</a>.</li>
Bill Wendlingbc5f6dd2011-10-26 18:33:01 +0000[diff] [blame]769
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]770<li>The linear scan register allocator has been replaced with a new "greedy"
771 register allocator, enabling live range splitting and many other
772 optimizations that lead to better code quality. Please see its <a
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]773 href="http://blog.llvm.org/2011/09/greedy-register-allocation-in-llvm-30.html">blog post</a> or its talk at the <a
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]774 href="http://llvm.org/devmtg/2011-11/">Developer Meeting</a>
775 for more information.</li>
Chris Lattner064caf92011-11-27 21:30:28 +0000[diff] [blame]776<li>LLVM IR now includes full support for <a href="Atomics.html">atomics
777 memory operations</a> intended to support the C++'11 and C'1x memory models.
778 This includes <a href="LangRef.html#memoryops">atomic load and store,
779 compare and exchange, and read/modify/write instructions</a> as well as a
780 full set of <a href="LangRef.html#ordering">memory ordering constraints</a>.
781 Please see the <a href="Atomics.html">Atomics Guide</a> for more
782 information.
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]783</li>
784<li>The LLVM IR exception handling representation has been redesigned and
785 reimplemented, making it more elegant, fixing a huge number of bugs, and
786 enabling inlining and other optimizations. Please see its blog post (XXX
Chris Lattner064caf92011-11-27 21:30:28 +0000[diff] [blame]787 not yet) and the <a href="ExceptionHandling.html">Exception Handling
788 documentation</a> for more information.</li>
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]789<li>The LLVM IR Type system has been redesigned and reimplemented, making it
790 faster and solving some long-standing problems.
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]791 Please see its <a
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]792 href="http://blog.llvm.org/2011/11/llvm-30-type-system-rewrite.html">blog
793 post</a> for more information.</li>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]794
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]795<li>The MIPS backend has made major leaps in this release, going from an
Chris Lattner064caf92011-11-27 21:30:28 +0000[diff] [blame]796 experimental target to being virtually production quality and supporting a
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]797 wide variety of MIPS subtargets. See the <a href="#MIPS">MIPS section</a>
798 below for more information.</li>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]799
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]800<li>The optimizer and code generator now supports gprof and gcov-style coverage
Chris Lattner064caf92011-11-27 21:30:28 +0000[diff] [blame]801 and profiling information, and includes a new llvm-cov tool (but also works
802 with gcov). Clang exposes coverage and profiling through GCC-compatible
803 command line options.</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]804</ul>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]805
Bill Wendlingbc5f6dd2011-10-26 18:33:01 +0000[diff] [blame]806</div>
807
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]808
Chris Lattner4f0fe432011-11-27 19:26:30 +0000[diff] [blame]809<!--=========================================================================-->
810<h3>
811<a name="coreimprovements">LLVM IR and Core Improvements</a>
812</h3>
813
814<div>
815
816<p>LLVM IR has several new features for better support of new targets and that
817 expose new optimization opportunities:</p>
818
Chris Lattner064caf92011-11-27 21:30:28 +0000[diff] [blame]819 <ul>
820 <li><a href="Atomics.html">Atomic memory accesses and memory ordering</a> are
821 now directly expressible in the IR.</li>
822 <li>A new <a href="LangRef.html#int_fma">llvm.fma intrinsic</a> directly
823 represents floating point multiply accumulate operations without an
824 intermediate rounding stage.</li>
825 <li>A new llvm.expect intrinsic (XXX not documented in langref) allows a
826 frontend to express expected control flow (and the __builtin_expect builtin
827 from GNU C).</li>
828 <li>The <a href="LangRef.html#int_prefetch">llvm.prefetch intrinsic</a> now
829 takes a 4th argument that specifies whether the prefetch happens from the
830 icache or dcache.</li>
831 <li>The new <a href="LangRef.html#uwtable">uwtable function attribute</a>
832 allows a frontend to control emission of unwind tables.</li>
833 <li>The new <a href="LangRef.html#fnattrs">nonlazybind function
834 attribute</a> allow optimization of Global Offset Table (GOT) accesses.</li>
835 <li>The new <a href="LangRef.html#returns_twice">returns_twice attribute</a>
836 allows better modeling of functions like setjmp.</li>
837 <li>The <a href="LangRef.html#datalayout">target datalayout</a> string can now
838 encode the natural alignment of the target's stack for better optimization.
839 </li>
840 </ul>
Andrew Trick5aab6382011-11-06 17:59:24 +0000[diff] [blame]841</div>
842
843<!--=========================================================================-->
844<h3>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]845<a name="optimizer">Optimizer Improvements</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]846</h3>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]847
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]848<div>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]849
Chris Lattner064caf92011-11-27 21:30:28 +0000[diff] [blame]850<p>In addition to many minor performance tweaks and bug fixes, this
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]851 release includes a few major enhancements and additions to the
852 optimizers:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]853
854<ul>
Chris Lattner064caf92011-11-27 21:30:28 +0000[diff] [blame]855<li>The pass manager now has an extension API that allows front-ends and plugins
856 to insert their own optimizations in the well-known places in the standard
857 pass optimization pipeline.</li>
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]858
Benjamin Kramer933a78c2011-11-26 11:14:54 +0000[diff] [blame]859<li>Information about <a href="BranchWeightMetadata.html">branch probability</a>
860 and basic block frequency is now available within LLVM, based on a
861 combination of static branch prediction heuristics and
862 <code>__builtin_expect</code> calls. That information is currently used for
863 register spill placement and if-conversion, with additional optimizations
864 planned for future releases. The same framework is intended for eventual
865 use with profile-guided optimization.</li>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]866
Chris Lattner064caf92011-11-27 21:30:28 +0000[diff] [blame]867<li>The "-indvars" induction variable simplification pass only modifies
868 induction variables when profitable. Sign and zero extension
869 elimination, linear function test replacement, loop unrolling, and
870 other simplifications that require induction variable analysis have
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]871 been generalized so they no longer require loops to be rewritten into
Chris Lattner064caf92011-11-27 21:30:28 +0000[diff] [blame]872 canonical form prior to optimization. This new design
873 preserves more IR level information, avoids undoing earlier loop
874 optimizations (particularly hand-optimized loops), and no longer
875 requires the code generator to reconstruct loops into an optimal form -
876 an intractable problem.</li>
877
878<li>LLVM now includes a pass to optimize retain/release calls for the
879 <a href="http://clang.llvm.org/docs/AutomaticReferenceCounting.html">Automatic
880 Reference Counting</a> (ARC) Objective-C language feature (in
Chris Lattner2f206022011-11-27 22:03:34 +0000[diff] [blame]881 lib/Transforms/Scalar/ObjCARC.cpp). It is a decent example of implementing
882 a source-language-specific optimization in LLVM.</li>
Chris Lattner064caf92011-11-27 21:30:28 +0000[diff] [blame]883
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]884</ul>
885
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]886</div>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]887
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]888<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]889<h3>
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]890<a name="mc">MC Level Improvements</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]891</h3>
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]892
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]893<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]894
895<p>The LLVM Machine Code (aka MC) subsystem was created to solve a number of
896 problems in the realm of assembly, disassembly, object file format handling,
897 and a number of other related areas that CPU instruction-set level tools work
Chris Lattner2f206022011-11-27 22:03:34 +0000[diff] [blame]898 in. For more information, please see
899 the <a href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro
900 to the LLVM MC Project Blog Post</a>.</p>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]901
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]902<ul>
Chris Lattner2f206022011-11-27 22:03:34 +0000[diff] [blame]903 <li>The MC layer has undergone significant refactoring to eliminate layering
904 violations that caused it to pull in the LLVM compiler backend code.</li>
905 <li>The ELF object file writers are much more full featured.</li>
906 <li>The integrated assembler now supports #line directives.</li>
907 <li>An early implementation of a JIT built on top of the MC framework (known
908 as MC-JIT) has been implemented and will eventually replace the old JIT.
909 It emits object files direct to memory and uses a runtime dynamic linker to
910 resolve references and drive lazy compilation. The MC-JIT enables much
911 greater code reuse between the JIT and the static compiler and provides
912 better integration with the platform ABI as a result.
913 </li>
914 <li>The assembly printer now makes uses of assemblers instruction aliases
915 (InstAliases) to print simplified mneumonics when possible.</li>
916 <li>TableGen can now autogenerate MC expansion logic for pseudo
917 instructions that expand to multiple MC instructions (through the
918 PseudoInstExpansion class).</li>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]919 <li>A new llvm-dwarfdump tool provides a start of a drop-in
920 replacement for the corresponding tool that use LLVM libraries. As part of
Chris Lattner7c224462011-11-27 22:39:23 +0000[diff] [blame]921 this, LLVM has the beginnings of a dwarf parsing library.</li>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]922 <li>llvm-objdump has more output including, symbol by symbol disassembly,
923 inline relocations, section headers, symbol tables, and section contents.
924 Support for archive files has also been added.</li>
925 <li>llvm-nm has gained support for archives of binary files.</li>
926 <li>llvm-size has been added. This tool prints out section sizes.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]927</ul>
928
NAKAMURA Takumi45c435a2011-04-05 08:24:22 +0000[diff] [blame]929</div>
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]930
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]931<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]932<h3>
Chris Lattner511433e2009-03-02 03:24:11 +0000[diff] [blame]933<a name="codegen">Target Independent Code Generator Improvements</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]934</h3>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]935
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]936<div>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]937
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]938<p>We have put a significant amount of work into the code generator
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]939 infrastructure, which allows us to implement more aggressive algorithms and
940 make it run faster:</p>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]941
942<ul>
Chris Lattner1cc489b2011-11-27 22:12:32 +0000[diff] [blame]943<li>XXX: Segmented stacks.</li>
Chris Lattner2f206022011-11-27 22:03:34 +0000[diff] [blame]944<li>LLVM generates substantially better code for indirect gotos due to a new
945 tail duplication pass, which can be a substantial performance win for
946 interpreter loops that use them.</li>
Rafael Espindola7ca7b532011-11-28 23:55:49 +0000[diff] [blame]947<li>Exception handling and debug frame information is now emitted with CFI
948 directives. This lets the assembler produce more compact info as it knows
949 the final offsets, yielding <a href="http://blog.mozilla.com/respindola/2011/05/12/cfi-directives/">much smaller executables</a> for some C++ applications.
950 If the system assembler doesn't support it, MC exands the directives when
951 the integrated assembler is not used.
Chris Lattner2f206022011-11-27 22:03:34 +0000[diff] [blame]952</li>
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]953
Chris Lattner2f206022011-11-27 22:03:34 +0000[diff] [blame]954<li>The code generator now supports vector "select" operations on vector
955 comparisons, turning them into various optimized code sequences (e.g.
956 using the SSE4/AVX "blend" instructions).</li>
Jakob Stoklund Olesen09e61ca2011-11-28 01:46:19 +0000[diff] [blame]957<li>The SSE execution domain fix pass and the ARM NEON move fix pass have been
Jakob Stoklund Olesen87f95dc2011-11-28 18:03:11 +0000[diff] [blame]958 merged to a target independent execution dependency fix pass. This pass is
959 used to select alternative equivalent opcodes in a way that minimizes
960 execution domain crossings. Closely connected instructions are moved to
961 the same execution domain when possible. Targets can override the
962 <code>getExecutionDomain</code> and <code>setExecutionDomain</code> hooks
963 to use the pass.</li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]964</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]965</div>
966
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]967<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]968<h3>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]969<a name="x86">X86-32 and X86-64 Target Improvements</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]970</h3>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]971
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]972<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]973
974<p>New features and major changes in the X86 target include:</p>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]975
976<ul>
Chris Lattner2f206022011-11-27 22:03:34 +0000[diff] [blame]977<li>The X86 backend, assembler and disassembler now have full support for AVX 1.
978 To enable it pass <code>-mavx</code> to the compiler. AVX2 implementation is
979 underway on mainline.</li>
980<li>The integrated assembler and disassembler now support a broad range of new
981 instructions including Atom, Ivy Bridge, <a
982 href="http://en.wikipedia.org/wiki/SSE4a">SSE4a/BMI</a> instructions, <a
983 href="http://en.wikipedia.org/wiki/RdRand">rdrand</a> and many others.</li>
984<li>The X86 backend now fully supports the <a href="http://llvm.org/PR879">X87
985 floating point stack inline assembly constraints</a>.</li>
986<li>The integrated assembler now supports the <tt>.code32</tt> and
987 <tt>.code64</tt> directives to switch between 32-bit and 64-bit
988 instructions.</li>
989<li>The X86 backend now synthesizes horizontal add/sub instructions from generic
990 vector code when the appropriate instructions are enabled.</li>
991<li>The X86-64 backend generates smaller and faster code at -O0 due to
992 improvements in fast instruction selection.</li>
993<li><a href="http://code.google.com/p/nativeclient/">Native Client</a>
994 subtarget support has been added.</li>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]995
Chris Lattner2f206022011-11-27 22:03:34 +0000[diff] [blame]996<li>The CRC32 intrinsics have been renamed. The intrinsics were previously
997 <code>@llvm.x86.sse42.crc32.[8|16|32]</code>
998 and <code>@llvm.x86.sse42.crc64.[8|64]</code>. They have been renamed to
999 <code>@llvm.x86.sse42.crc32.32.[8|16|32]</code> and
1000 <code>@llvm.x86.sse42.crc32.64.[8|64]</code>.</li>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]1001</ul>
1002
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]1003</div>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]1004
1005<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]1006<h3>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]1007<a name="ARM">ARM Target Improvements</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]1008</h3>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]1009
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]1010<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1011
1012<p>New features of the ARM target include:</p>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]1013
1014<ul>
Chris Lattner1cc489b2011-11-27 22:12:32 +0000[diff] [blame]1015<li>The ARM backend generates much faster code for Cortex-A9 chips.</li>
1016<li>The ARM backend has improved support for Cortex-M series processors.</li>
1017<li>The ARM inline assembly constraints have been implemented and are now fully
1018 supported.</li>
1019<li>NEON code produced by Clang often runs much faster due to improvements in
1020 the Scalar Replacement of Aggregates pass.</li>
1021<li>The old ARM disassembler is replaced with a new one based on autogenerated
1022 encoding information from ARM .td files.</li>
1023<li>The integrated assembler has made major leaps forward, but is still beta quality in LLVM 3.0.</li>
Bob Wilsone8472772010-09-13 17:39:35 +0000[diff] [blame]1024</ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]1025</div>
Chris Lattner7b95c382011-11-15 22:23:46 +0000[diff] [blame]1026
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]1027
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]1028<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]1029<h3>
Akira Hatanaka5381cbf2011-11-15 21:33:05 +0000[diff] [blame]1030<a name="MIPS">MIPS Target Improvements</a>
1031</h3>
1032
1033<div>
1034
Chris Lattner1cc489b2011-11-27 22:12:32 +0000[diff] [blame]1035<p>This release has seen major new work on just about every aspect of the MIPS
1036 backend. Some of the major new features include:</p>
Akira Hatanaka5381cbf2011-11-15 21:33:05 +0000[diff] [blame]1037
1038<ul>
1039 <li>Most MIPS32r1 and r2 instructions are now supported.</li>
1040 <li>LE/BE MIPS32r1/r2 has been tested extensively.</li>
1041 <li>O32 ABI has been fully tested.</li>
1042 <li>MIPS backend has migrated to using the MC infrastructure for assembly printing. Initial support for direct object code emission has been implemented too.</li>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]1043 <li>Delay slot filler has been updated. Now it tries to fill delay slots with useful instructions instead of always filling them with NOPs.</li>
Akira Hatanaka5381cbf2011-11-15 21:33:05 +0000[diff] [blame]1044 <li>Support for old-style JIT is complete.</li>
1045 <li>Support for old architectures (MIPS1 and MIPS2) has been removed.</li>
1046 <li>Initial support for MIPS64 has been added.</li>
1047</ul>
1048</div>
Chris Lattner7b95c382011-11-15 22:23:46 +0000[diff] [blame]1049
1050<!--=========================================================================-->
1051<h3>
1052 <a name="PTX">PTX Target Improvements</a>
1053</h3>
1054
1055<div>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]1056
Chris Lattner7b95c382011-11-15 22:23:46 +0000[diff] [blame]1057 <p>
1058 The PTX back-end is still experimental, but is fairly usable for compute kernels
1059 in LLVM 3.0. Most scalar arithmetic is implemented, as well as intrinsics to
1060 access the special PTX registers and sync instructions. The major missing
1061 pieces are texture/sampler support and some vector operations.</p>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]1062
Chris Lattner7b95c382011-11-15 22:23:46 +0000[diff] [blame]1063 <p>That said, the backend is already being used for domain-specific languages
1064 and works well with the <a href="http://www.pcc.me.uk/~peter/libclc/">libclc
1065 library</a> to supply OpenCL built-ins. With it, you can use Clang to compile
1066 OpenCL code into PTX and execute it by loading the resulting PTX as a binary
1067 blob using the nVidia OpenCL library. It has been tested with several OpenCL
1068 programs, including some from the nVidia GPU Computing SDK, and the performance
1069 is on par with the nVidia compiler.</p>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]1070
Chris Lattner7b95c382011-11-15 22:23:46 +0000[diff] [blame]1071</div>
1072
Akira Hatanaka5381cbf2011-11-15 21:33:05 +0000[diff] [blame]1073<!--=========================================================================-->
1074<h3>
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]1075<a name="OtherTS">Other Target Specific Improvements</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]1076</h3>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]1077
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]1078<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1079
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]1080<ul>
Chris Lattnerd6cc2c22011-11-27 22:36:22 +0000[diff] [blame]1081<li>Many PowerPC improvements have been implemented for ELF targets, including
1082 support for varargs and initial support for direct .o file emission.</li>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]1083
Chris Lattnerd6cc2c22011-11-27 22:36:22 +0000[diff] [blame]1084<li>MicroBlaze scheduling itineraries were added that model the
1085 3-stage and the 5-stage pipeline architectures. The 3-stage
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]1086 pipeline model can be selected with <code>-mcpu=mblaze3</code>
1087 and the 5-stage pipeline model can be selected with
Chris Lattnerd6cc2c22011-11-27 22:36:22 +0000[diff] [blame]1088 <code>-mcpu=mblaze5</code>.</li>
1089
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]1090</ul>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1091
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]1092</div>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]1093
1094<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]1095<h3>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]1096<a name="changes">Major Changes and Removed Features</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]1097</h3>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]1098
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]1099<div>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]1100
Bill Wendling2626dba2011-08-03 22:18:20 +0000[diff] [blame]1101<p>If you're already an LLVM user or developer with out-of-tree changes based on
1102 LLVM 2.9, this section lists some "gotchas" that you may run into upgrading
1103 from the previous release.</p>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]1104
1105<ul>
Chris Lattnerd6cc2c22011-11-27 22:36:22 +0000[diff] [blame]1106<li>LLVM 3.0 removes support for reading LLVM 2.8 and earlier files, and LLVM
1107 3.1 will eliminate support for reading LLVM 2.9 files. Going forward, we
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]1108 aim for all future versions of LLVM to read bitcode files and .ll files
Chris Lattnerd6cc2c22011-11-27 22:36:22 +0000[diff] [blame]1109 produced by LLVM 3.0.</li>
1110<li>Tablegen has been split into a library, allowing the clang tblgen pieces
1111 now live in the clang tree. The llvm version has been renamed to
1112 llvm-tblgen instead of tblgen.</li>
Chris Lattner5a1731d2011-11-27 08:32:32 +0000[diff] [blame]1113 <li>The <code>LLVMC</code> meta compiler driver was removed.</li>
Chris Lattnerd6cc2c22011-11-27 22:36:22 +0000[diff] [blame]1114 <li>The unused PostOrder Dominator Frontiers and LowerSetJmp passes were removed.</li>
1115
1116
Rafael Espindolaf940a1a2011-08-30 23:03:45 +0000[diff] [blame]1117 <li>The old <code>TailDup</code> pass was not used in the standard pipeline
1118 and was unable to update ssa form, so it has been removed.
Eli Friedmanf03bb262011-08-12 22:50:01 +0000[diff] [blame]1119 <li>The syntax of volatile loads and stores in IR has been changed to
1120 "<code>load volatile</code>"/"<code>store volatile</code>". The old
1121 syntax ("<code>volatile load</code>"/"<code>volatile store</code>")
Chris Lattnerd6cc2c22011-11-27 22:36:22 +0000[diff] [blame]1122 is still accepted, but is now considered deprecated and will be removed in
1123 3.1.</li>
1124 <li>llvm-gcc's frontend tests have been removed from llvm/test/Frontend*, sunk
1125 into the clang and dragonegg testsuites.</li>
Benjamin Kramer7c5025b2011-11-25 21:26:00 +0000[diff] [blame]1126 <li>The old atomic intrinsics (<code>llvm.memory.barrier</code> and
Eli Friedman526e1bb2011-10-26 00:55:23 +0000[diff] [blame]1127 <code>llvm.atomic.*</code>) are now gone. Please use the new atomic
1128 instructions, described in the <a href="Atomics.html">atomics guide</a>.
Chris Lattnerd6cc2c22011-11-27 22:36:22 +0000[diff] [blame]1129 <li>LLVM's configure script doesn't depend on llvm-gcc anymore, eliminating a
1130 strange circular dependence between projects.</li>
Devang Patelb34dd132008-10-14 20:03:43 +0000[diff] [blame]1131</ul>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]1132
NAKAMURA Takumi2026de22011-08-22 23:22:05 +0000[diff] [blame]1133<h4>Windows (32-bit)</h4>
1134<div>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1135
NAKAMURA Takumi2026de22011-08-22 23:22:05 +0000[diff] [blame]1136<ul>
1137 <li>On Win32(MinGW32 and MSVC), Windows 2000 will not be supported.
1138 Windows XP or higher is required.</li>
1139</ul>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1140
NAKAMURA Takumi2026de22011-08-22 23:22:05 +0000[diff] [blame]1141</div>
1142
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]1143</div>
1144
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000[diff] [blame]1145<!--=========================================================================-->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]1146<h3>
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]1147<a name="api_changes">Internal API Changes</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]1148</h3>
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000[diff] [blame]1149
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]1150<div>
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000[diff] [blame]1151
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]1152<p>In addition, many APIs have changed in this release. Some of the major
Bill Wendling16005252011-08-02 06:20:17 +0000[diff] [blame]1153 LLVM API changes are:</p>
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000[diff] [blame]1154
1155<ul>
Joe Abbey54d3b832011-11-28 22:07:12 +0000[diff] [blame]1156 <li>The biggest and most pervasive change is that the type system has been
1157 rewritten: <code>PATypeHolder</code> and <code>OpaqueType</code> are gone,
1158 and all APIs deal with <code>Type*</code> instead of <code>const
1159 Type*</code>. If you need to create recursive structures, then create a
1160 named structure, and use <code>setBody()</code> when all its elements are
1161 built. Type merging and refining is gone too: named structures are not
1162 merged with other structures, even if their layout is identical. (of
1163 course anonymous structures are still uniqued by layout).</li>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]1164
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1165 <li><code>PHINode::reserveOperandSpace</code> has been removed. Instead, you
1166 must specify how many operands to reserve space for when you create the
1167 PHINode, by passing an extra argument
1168 into <code>PHINode::Create</code>.</li>
Jay Foad558d3762011-07-14 09:19:05 +0000[diff] [blame]1169
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1170 <li>PHINodes no longer store their incoming BasicBlocks as operands. Instead,
1171 the list of incoming BasicBlocks is stored separately, and can be accessed
1172 with new functions <code>PHINode::block_begin</code>
1173 and <code>PHINode::block_end</code>.</li>
Jay Foad558d3762011-07-14 09:19:05 +0000[diff] [blame]1174
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1175 <li>Various functions now take an <code>ArrayRef</code> instead of either a
1176 pair of pointers (or iterators) to the beginning and end of a range, or a
1177 pointer and a length. Others now return an <code>ArrayRef</code> instead
1178 of a reference to a <code>SmallVector</code>
1179 or <code>std::vector</code>. These include:
Jay Foad558d3762011-07-14 09:19:05 +0000[diff] [blame]1180<ul>
1181<!-- Please keep this list sorted. -->
Jay Foada3efbb12011-07-15 08:37:34 +0000[diff] [blame]1182<li><code>CallInst::Create</code></li>
Jay Foad558d3762011-07-14 09:19:05 +0000[diff] [blame]1183<li><code>ComputeLinearIndex</code> (in <code>llvm/CodeGen/Analysis.h</code>)</li>
1184<li><code>ConstantArray::get</code></li>
1185<li><code>ConstantExpr::getExtractElement</code></li>
Jay Foaddab3d292011-07-21 14:31:17 +0000[diff] [blame]1186<li><code>ConstantExpr::getGetElementPtr</code></li>
1187<li><code>ConstantExpr::getInBoundsGetElementPtr</code></li>
Jay Foad558d3762011-07-14 09:19:05 +0000[diff] [blame]1188<li><code>ConstantExpr::getIndices</code></li>
1189<li><code>ConstantExpr::getInsertElement</code></li>
1190<li><code>ConstantExpr::getWithOperands</code></li>
Jay Foad1d2f5692011-07-19 13:32:40 +0000[diff] [blame]1191<li><code>ConstantFoldCall</code> (in <code>llvm/Analysis/ConstantFolding.h</code>)</li>
1192<li><code>ConstantFoldInstOperands</code> (in <code>llvm/Analysis/ConstantFolding.h</code>)</li>
Jay Foad558d3762011-07-14 09:19:05 +0000[diff] [blame]1193<li><code>ConstantVector::get</code></li>
1194<li><code>DIBuilder::createComplexVariable</code></li>
1195<li><code>DIBuilder::getOrCreateArray</code></li>
1196<li><code>ExtractValueInst::Create</code></li>
1197<li><code>ExtractValueInst::getIndexedType</code></li>
1198<li><code>ExtractValueInst::getIndices</code></li>
1199<li><code>FindInsertedValue</code> (in <code>llvm/Analysis/ValueTracking.h</code>)</li>
Jay Foadca12a212011-07-19 14:42:50 +0000[diff] [blame]1200<li><code>gep_type_begin</code> (in <code>llvm/Support/GetElementPtrTypeIterator.h</code>)</li>
1201<li><code>gep_type_end</code> (in <code>llvm/Support/GetElementPtrTypeIterator.h</code>)</li>
Jay Foada9203102011-07-25 09:48:08 +0000[diff] [blame]1202<li><code>GetElementPtrInst::Create</code></li>
1203<li><code>GetElementPtrInst::CreateInBounds</code></li>
1204<li><code>GetElementPtrInst::getIndexedType</code></li>
Jay Foadb60e8512011-07-21 14:42:51 +0000[diff] [blame]1205<li><code>InsertValueInst::Create</code></li>
1206<li><code>InsertValueInst::getIndices</code></li>
1207<li><code>InvokeInst::Create</code></li>
Jay Foada3efbb12011-07-15 08:37:34 +0000[diff] [blame]1208<li><code>IRBuilder::CreateCall</code></li>
Jay Foad558d3762011-07-14 09:19:05 +0000[diff] [blame]1209<li><code>IRBuilder::CreateExtractValue</code></li>
Jay Foad0a2a60a2011-07-22 08:16:57 +0000[diff] [blame]1210<li><code>IRBuilder::CreateGEP</code></li>
1211<li><code>IRBuilder::CreateInBoundsGEP</code></li>
Jay Foad558d3762011-07-14 09:19:05 +0000[diff] [blame]1212<li><code>IRBuilder::CreateInsertValue</code></li>
Jay Foada3efbb12011-07-15 08:37:34 +0000[diff] [blame]1213<li><code>IRBuilder::CreateInvoke</code></li>
Jay Foad558d3762011-07-14 09:19:05 +0000[diff] [blame]1214<li><code>MDNode::get</code></li>
1215<li><code>MDNode::getIfExists</code></li>
1216<li><code>MDNode::getTemporary</code></li>
1217<li><code>MDNode::getWhenValsUnresolved</code></li>
Jay Foadb9b54eb2011-07-19 15:07:52 +0000[diff] [blame]1218<li><code>SimplifyGEPInst</code> (in <code>llvm/Analysis/InstructionSimplify.h</code>)</li>
Jay Foad8fbbb392011-07-19 14:01:37 +0000[diff] [blame]1219<li><code>TargetData::getIndexedOffset</code></li>
Jay Foad558d3762011-07-14 09:19:05 +0000[diff] [blame]1220</ul></li>
1221
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1222 <li>All forms of <code>StringMap::getOrCreateValue</code> have been remove
1223 except for the one which takes a <code>StringRef</code>.</li>
Jay Foad558d3762011-07-14 09:19:05 +0000[diff] [blame]1224
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1225 <li>The <code>LLVMBuildUnwind</code> function from the C API was removed. The
1226 LLVM <code>unwind</code> instruction has been deprecated for a long time
1227 and isn't used by the current front-ends. So this was removed during the
1228 exception handling rewrite.</li>
Bill Wendling16005252011-08-02 06:20:17 +0000[diff] [blame]1229
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1230 <li>The <code>LLVMAddLowerSetJmpPass</code> function from the C API was
1231 removed because the <code>LowerSetJmp</code> pass was removed.</li>
Bill Wendling2626dba2011-08-03 22:18:20 +0000[diff] [blame]1232
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1233 <li>The <code>DIBuilder</code> interface used by front ends to encode
1234 debugging information in the LLVM IR now expects clients to
1235 use <code>DIBuilder::finalize()</code> at the end of translation unit to
1236 complete debugging information encoding.</li>
Devang Patel6326a422011-08-15 23:00:00 +0000[diff] [blame]1237
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1238 <li>TargetSelect.h moved to Support/ from Target/</li>
Torok Edwinf16e2d42011-09-30 13:07:52 +0000[diff] [blame]1239
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1240 <li>UpgradeIntrinsicCall no longer upgrades pre-2.9 intrinsic calls (for
1241 example <code>llvm.memset.i32</code>).</li>
Torok Edwinf16e2d42011-09-30 13:07:52 +0000[diff] [blame]1242
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1243 <li>It is mandatory to initialize all out-of-tree passes too and their dependencies now with
1244 <code>INITIALIZE_PASS{BEGIN,END,}</code>
1245 and <code>INITIALIZE_{PASS,AG}_DEPENDENCY</code>.</li>
Torok Edwinf16e2d42011-09-30 13:07:52 +0000[diff] [blame]1246
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1247 <li>The interface for MemDepResult in MemoryDependenceAnalysis has been
1248 enhanced with new return types Unknown and NonFuncLocal, in addition to
1249 the existing types Clobber, Def, and NonLocal.</li>
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000[diff] [blame]1250</ul>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1251
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000[diff] [blame]1252</div>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]1253
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]1254</div>
1255
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1256<!-- *********************************************************************** -->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]1257<h2>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1258 <a name="knownproblems">Known Problems</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]1259</h2>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1260<!-- *********************************************************************** -->
1261
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]1262<div>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1263
Chris Lattner70e22012011-11-27 19:38:20 +0000[diff] [blame]1264<p>LLVM is generally a production quality compiler, and is used by a broad range
1265 of applications and shipping in many products. That said, not every
1266 subsystem is as mature as the aggregate, particularly the more obscure
1267 targets. If you run into a problem, please check the <a
1268 href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
1269 there isn't already one or ask on the <a
1270 href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev
1271 list</a>.</p>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]1272
Chris Lattner70e22012011-11-27 19:38:20 +0000[diff] [blame]1273 <p>Known problem areas include:</p>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]1274
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]1275<ul>
Chris Lattner70e22012011-11-27 19:38:20 +0000[diff] [blame]1276 <li>The Alpha, Blackfin, CellSPU, MSP430, PTX, SystemZ and
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]1277 XCore backends are experimental, and the Alpha, Blackfin and SystemZ
1278 targets have already been removed from mainline.</li>
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1279
Chris Lattner70e22012011-11-27 19:38:20 +0000[diff] [blame]1280 <li>The integrated assembler, disassembler, and JIT is not supported by
1281 several targets. If an integrated assembler is not supported, then a
1282 system assembler is required. For more details, see the <a
1283 href="CodeGenerator.html#targetfeatures">Target Features Matrix</a>.
1284 </li>
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]1285
Chris Lattner70e22012011-11-27 19:38:20 +0000[diff] [blame]1286 <li>The C backend has numerous problems and is not being actively maintained.
1287 Depending on it for anything serious is not advised.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1288</ul>
1289
1290</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]1291
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]1292</div>
1293
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1294<!-- *********************************************************************** -->
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]1295<h2>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1296 <a name="additionalinfo">Additional Information</a>
NAKAMURA Takumi06c6d9a2011-04-18 01:17:51 +0000[diff] [blame]1297</h2>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1298<!-- *********************************************************************** -->
1299
NAKAMURA Takumi074eeaa2011-04-21 01:52:00 +0000[diff] [blame]1300<div>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1301
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1302<p>A wide variety of additional information is available on
1303 the <a href="http://llvm.org/">LLVM web page</a>, in particular in
1304 the <a href="http://llvm.org/docs/">documentation</a> section. The web page
1305 also contains versions of the API documentation which is up-to-date with the
1306 Subversion version of the source code. You can access versions of these
1307 documents specific to this release by going into the "<tt>llvm/doc/</tt>"
1308 directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1309
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1310<p>If you have any questions or comments about LLVM, please feel free to contact
Bill Wendling7b7fa742011-10-26 18:46:16 +0000[diff] [blame]1311 us via the <a href="http://llvm.org/docs/#maillist"> mailing lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1312
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1313</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1314
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]1315<!--=========================================================================-->
1316
1317<!-- EH details: to be moved to a blog post:
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]1318
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]1319
1320
1321
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]1322<p>One of the biggest changes is that 3.0 has a new exception handling
1323 system. The old system used LLVM intrinsics to convey the exception handling
1324 information to the code generator. It worked in most cases, but not
1325 all. Inlining was especially difficult to get right. Also, the intrinsics
1326 could be moved away from the <code>invoke</code> instruction, making it hard
1327 to recover that information.</p>
1328
1329<p>The new EH system makes exception handling a first-class member of the IR. It
1330 adds two new instructions:</p>
1331
1332<ul>
1333 <li><a href="LangRef.html#i_landingpad"><code>landingpad</code></a> &mdash;
1334 this instruction defines a landing pad basic block. It contains all of the
1335 information that's needed by the code generator. It's also required to be
1336 the first non-PHI instruction in the landing pad. In addition, a landing
1337 pad may be jumped to only by the unwind edge of an <code>invoke</code>
1338 instruction.</li>
1339
1340 <li><a href="LangRef.html#i_resume"><code>resume</code></a> &mdash; this
1341 instruction causes the current exception to resume traveling up the
1342 stack. It replaces the <code>@llvm.eh.resume</code> intrinsic.</li>
1343</ul>
1344
1345<p>Converting from the old EH API to the new EH API is rather simple, because a
1346 lot of complexity has been removed. The two intrinsics,
1347 <code>@llvm.eh.exception</code> and <code>@llvm.eh.selector</code> have been
1348 superseded by the <code>landingpad</code> instruction. Instead of generating
1349 a call to <code>@llvm.eh.exception</code> and <code>@llvm.eh.selector</code>:
1350
1351<div class="doc_code">
1352<pre>
1353Function *ExcIntr = Intrinsic::getDeclaration(TheModule,
1354 Intrinsic::eh_exception);
1355Function *SlctrIntr = Intrinsic::getDeclaration(TheModule,
1356 Intrinsic::eh_selector);
1357
1358// The exception pointer.
1359Value *ExnPtr = Builder.CreateCall(ExcIntr, "exc_ptr");
1360
1361std::vector&lt;Value*&gt; Args;
1362Args.push_back(ExnPtr);
1363Args.push_back(Builder.CreateBitCast(Personality,
1364 Type::getInt8PtrTy(Context)));
1365
1366<i>// Add selector clauses to Args.</i>
1367
1368// The selector call.
1369Builder.CreateCall(SlctrIntr, Args, "exc_sel");
1370</pre>
1371</div>
1372
1373<p>You should instead generate a <code>landingpad</code> instruction, that
1374 returns an exception object and selector value:</p>
1375
1376<div class="doc_code">
1377<pre>
1378LandingPadInst *LPadInst =
1379 Builder.CreateLandingPad(StructType::get(Int8PtrTy, Int32Ty, NULL),
1380 Personality, 0);
1381
1382Value *LPadExn = Builder.CreateExtractValue(LPadInst, 0);
1383Builder.CreateStore(LPadExn, getExceptionSlot());
1384
1385Value *LPadSel = Builder.CreateExtractValue(LPadInst, 1);
1386Builder.CreateStore(LPadSel, getEHSelectorSlot());
1387</pre>
1388</div>
1389
1390<p>It's now trivial to add the individual clauses to the <code>landingpad</code>
1391 instruction.</p>
1392
1393<div class="doc_code">
1394<pre>
1395<i><b>// Adding a catch clause</b></i>
1396Constant *TypeInfo = getTypeInfo();
1397LPadInst-&gt;addClause(TypeInfo);
1398
1399<i><b>// Adding a C++ catch-all</b></i>
1400LPadInst-&gt;addClause(Constant::getNullValue(Builder.getInt8PtrTy()));
1401
1402<i><b>// Adding a cleanup</b></i>
1403LPadInst-&gt;setCleanup(true);
1404
1405<i><b>// Adding a filter clause</b></i>
1406std::vector&lt;Constant*&gt; TypeInfos;
1407Constant *TypeInfo = getFilterTypeInfo();
1408TypeInfos.push_back(Builder.CreateBitCast(TypeInfo, Builder.getInt8PtrTy()));
1409
1410ArrayType *FilterTy = ArrayType::get(Int8PtrTy, TypeInfos.size());
1411LPadInst-&gt;addClause(ConstantArray::get(FilterTy, TypeInfos));
1412</pre>
1413</div>
1414
1415<p>Converting from using the <code>@llvm.eh.resume</code> intrinsic to
1416 the <code>resume</code> instruction is trivial. It takes the exception
1417 pointer and exception selector values returned by
1418 the <code>landingpad</code> instruction:</p>
1419
1420<div class="doc_code">
1421<pre>
1422Type *UnwindDataTy = StructType::get(Builder.getInt8PtrTy(),
1423 Builder.getInt32Ty(), NULL);
1424Value *UnwindData = UndefValue::get(UnwindDataTy);
1425Value *ExcPtr = Builder.CreateLoad(getExceptionObjSlot());
1426Value *ExcSel = Builder.CreateLoad(getExceptionSelSlot());
1427UnwindData = Builder.CreateInsertValue(UnwindData, ExcPtr, 0, "exc_ptr");
1428UnwindData = Builder.CreateInsertValue(UnwindData, ExcSel, 1, "exc_sel");
1429Builder.CreateResume(UnwindData);
1430</pre>
1431</div>
1432
1433
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]1434
1435
Chris Lattner1c80fbf2011-11-27 20:51:47 +0000[diff] [blame]1436 -->
1437
Michael J. Spencer60f790c2011-11-28 18:20:09 +0000[diff] [blame]1438
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1439<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1440
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1441<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]1442<address>
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Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]1448 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
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