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gerrit-public.fairphone.software / toolchain / llvm-project / c3a2c9817ccb5fb94be40013731cab61315aef00 / . / llvm / docs / ReleaseNotes.html
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Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]8 <title>LLVM 2.9 Release Notes</title>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]9</head>
10<body>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]11
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]12<h1 class="doc_title">LLVM 2.9 Release Notes</h1>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]13
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]14<img align=right src="http://llvm.org/img/DragonSmall.png"
Gabor Greif27b166352010-04-22 10:21:43 +0000[diff] [blame]15 width="136" height="136" alt="LLVM Dragon Logo">
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]16
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]17<ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]18 <li><a href="#intro">Introduction</a></li>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]19 <li><a href="#subproj">Sub-project Status Update</a></li>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]20 <li><a href="#externalproj">External Projects Using LLVM 2.9</a></li>
21 <li><a href="#whatsnew">What's New in LLVM 2.9?</a></li>
Chris Lattner77a51732004-04-30 22:17:12 +0000[diff] [blame]22 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Dan Gohmanad888912008-10-14 16:23:02 +0000[diff] [blame]23 <li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]24 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]25</ol>
26
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]27<div class="doc_author">
Dan Gohmanad888912008-10-14 16:23:02 +0000[diff] [blame]28 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]29</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]30
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]31<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.9
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]32release.<br>
33You may prefer the
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]34<a href="http://llvm.org/releases/2.8/docs/ReleaseNotes.html">LLVM 2.8
Dan Gohman62af9d22010-05-03 23:51:05 +0000[diff] [blame]35Release Notes</a>.</h1>
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]36
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]37<!-- *********************************************************************** -->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]38<h1>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]39 <a name="intro">Introduction</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]40</h1>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]41<!-- *********************************************************************** -->
42
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]43<div class="doc_text">
44
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]45<p>This document contains the release notes for the LLVM Compiler
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]46Infrastructure, release 2.9. Here we describe the status of LLVM, including
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]47major improvements from the previous release and significant known problems.
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]48All LLVM releases may be downloaded from the <a
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]49href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]50
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]51<p>For more information about LLVM, including information about the latest
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]52release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattnere7525b52003-10-07 21:38:31 +0000[diff] [blame]53web site</a>. If you have questions or comments, the <a
Chris Lattner0b1c9a52010-03-17 04:41:49 +0000[diff] [blame]54href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's
55Mailing List</a> is a good place to send them.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]56
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]57<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]58main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greif355f81c2008-10-14 11:00:32 +0000[diff] [blame]59current one. To see the release notes for a specific release, please see the
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]60<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]61
62</div>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]63
Chris Lattnerce6b0472011-04-05 23:22:33 +0000[diff] [blame]64<!-- Features that need text if they're finished for 3.1:
65 ARM EHABI
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]66 combiner-aa?
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]67 strong phi elim
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]68 loop dependence analysis
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]69 CorrelatedValuePropagation
Chris Lattnerce6b0472011-04-05 23:22:33 +0000[diff] [blame]70 lib/Transforms/IPO/MergeFunctions.cpp => consider for 3.1.
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]71 -->
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]72
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]73<!-- *********************************************************************** -->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]74<h1>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]75 <a name="subproj">Sub-project Status Update</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]76</h1>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]77<!-- *********************************************************************** -->
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]78
79<div class="doc_text">
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]80<p>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]81The LLVM 2.9 distribution currently consists of code from the core LLVM
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]82repository (which roughly includes the LLVM optimizers, code generators
83and supporting tools), the Clang repository and the llvm-gcc repository. In
84addition to this code, the LLVM Project includes other sub-projects that are in
85development. Here we include updates on these subprojects.
Bill Wendlingf170d2e2009-03-02 04:28:57 +0000[diff] [blame]86</p>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]87
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]88</div>
89
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]90
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]91<!--=========================================================================-->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]92<h2>
Chris Lattner44c09cd2008-10-13 18:11:54 +0000[diff] [blame]93<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]94</h2>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]95
96<div class="doc_text">
97
Chris Lattner5de7f6e2010-04-26 17:42:18 +0000[diff] [blame]98<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
99C++, and Objective-C languages. Clang aims to provide a better user experience
100through expressive diagnostics, a high level of conformance to language
101standards, fast compilation, and low memory use. Like LLVM, Clang provides a
102modular, library-based architecture that makes it suitable for creating or
103integrating with other development tools. Clang is considered a
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]104production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]105(32- and 64-bit), and for darwin/arm targets.</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]106
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]107<p>In the LLVM 2.9 time-frame, the Clang team has made many improvements in C,
108C++ and Objective-C support. C++ support is now generally rock solid, has
109been exercised on a broad variety of code, and has several new C++'0x features
110implemented (such as rvalue references and variadic templates). LLVM 2.9 has
111also brought in a large range of bug fixes and minor features (e.g. __label__
112support), and is much more compatible with the Linux Kernel.</p>
113
114<p>If Clang rejects your code that is built with another compiler, please take a
115look at the <a href="http://clang.llvm.org/compatibility.html">language
116compatibility</a> guide to make sure the issue isn't intentional or a known
117issue.
118</p>
Bill Wendlingef362462008-10-27 09:27:33 +0000[diff] [blame]119
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]120<ul>
121</ul>
Chris Lattner44c09cd2008-10-13 18:11:54 +0000[diff] [blame]122</div>
123
124<!--=========================================================================-->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]125<h2>
Duncan Sands1cd78982011-04-04 11:09:08 +0000[diff] [blame]126<a name="dragonegg">DragonEgg: GCC front-ends, LLVM back-end</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]127</h2>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]128
129<div class="doc_text">
130<p>
Duncan Sands1cd78982011-04-04 11:09:08 +0000[diff] [blame]131<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a
132<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin</a> that replaces GCC's
133optimizers and code generators with LLVM's.
134Currently it requires a patched version of gcc-4.5.
135The plugin can target the x86-32 and x86-64 processor families and has been
136used successfully on the Darwin, FreeBSD and Linux platforms.
137The Ada, C, C++ and Fortran languages work well.
138The plugin is capable of compiling plenty of Obj-C, Obj-C++ and Java but it is
139not known whether the compiled code actually works or not!
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]140</p>
141
142<p>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]143The 2.9 release has the following notable changes:
Duncan Sands7f9a0dc2010-09-30 17:37:34 +0000[diff] [blame]144<ul>
Duncan Sands1cd78982011-04-04 11:09:08 +0000[diff] [blame]145<li>The plugin is much more stable when compiling Fortran.</li>
146<li>Inline asm where an asm output is tied to an input of a different size is
147now supported in many more cases.</li>
148<li>Basic support for the __float128 type was added. It is now possible to
149generate LLVM IR from programs using __float128 but code generation does not
150work yet.</li>
151<li>Compiling Java programs no longer systematically crashes the plugin.</li>
Duncan Sands7f9a0dc2010-09-30 17:37:34 +0000[diff] [blame]152</ul>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]153
154</div>
155
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]156<!--=========================================================================-->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]157<h2>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]158<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]159</h2>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]160
161<div class="doc_text">
162<p>
163The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
164is a simple library that provides an implementation of the low-level
165target-specific hooks required by code generation and other runtime components.
166For example, when compiling for a 32-bit target, converting a double to a 64-bit
167unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
168function. The compiler-rt library provides highly optimized implementations of
169this and other low-level routines (some are 3x faster than the equivalent
170libgcc routines).</p>
171
172<p>
173All of the code in the compiler-rt project is available under the standard LLVM
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]174License, a "BSD-style" license.
175
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]176compiler_rt is now dual licensed under MIT and UIUC license
177
178Several minor changes for better ARM support.
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]179
180New in LLVM 2.9, UPDATE</p>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]181
182</div>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]183
184<!--=========================================================================-->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]185<h2>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]186<a name="lldb">LLDB: Low Level Debugger</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]187</h2>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]188
189<div class="doc_text">
190<p>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]191<a href="http://lldb.llvm.org/">LLDB</a> is a brand new member of the LLVM
192umbrella of projects. LLDB is a next generation, high-performance debugger. It
193is built as a set of reusable components which highly leverage existing
194libraries in the larger LLVM Project, such as the Clang expression parser, the
195LLVM disassembler and the LLVM JIT.</p>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]196
197<p>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]198LLDB is in early development and not included as part of the LLVM 2.9 release,
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]199
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]200
201
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]202<!--
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]203but is mature enough to support basic debugging scenarios on Mac OS X in C,
204Objective-C and C++. We'd really like help extending and expanding LLDB to
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]205support new platforms, new languages, new architectures, and new features.-->
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]206</p>
207
208</div>
209
210<!--=========================================================================-->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]211<h2>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]212<a name="libc++">libc++: C++ Standard Library</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]213</h2>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]214
215<div class="doc_text">
216<p>
Tobias Grosser436bc5f2010-10-06 21:07:30 +0000[diff] [blame]217<a href="http://libcxx.llvm.org/">libc++</a> is another new member of the LLVM
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]218family. It is an implementation of the C++ standard library, written from the
219ground up to specifically target the forthcoming C++'0X standard and focus on
220delivering great performance.</p>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]221
222<p>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]223As of the LLVM 2.9 release, UPDATE!
224
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]225libc++ is now dual licensed under MIT and UIUC license
226
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]227<!--libc++ is virtually feature complete, but would
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]228benefit from more testing and better integration with Clang++. It is also
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]229looking forward to the C++ committee finalizing the C++'0x standard.-->
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]230</p>
231
232</div>
233
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]234
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]235
236<!--=========================================================================-->
Chris Lattner9ee0b012011-04-05 18:38:45 +0000[diff] [blame]237<!--
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]238<h2>
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]239<a name="klee">KLEE: A Symbolic Execution Virtual Machine</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]240</h2>
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]241
242<div class="doc_text">
243<p>
244<a href="http://klee.llvm.org/">KLEE</a> is a symbolic execution framework for
245programs in LLVM bitcode form. KLEE tries to symbolically evaluate "all" paths
246through the application and records state transitions that lead to fault
247states. This allows it to construct testcases that lead to faults and can even
248be used to verify some algorithms.
249</p>
250
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]251<p>UPDATE!</p>
Chris Lattner9ee0b012011-04-05 18:38:45 +0000[diff] [blame]252</div>-->
Daniel Dunbar8fbd8aa2010-10-04 17:39:47 +0000[diff] [blame]253
254
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]255<!-- *********************************************************************** -->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]256<h1>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]257 <a name="externalproj">External Open Source Projects Using LLVM 2.9</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]258</h1>
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]259<!-- *********************************************************************** -->
260
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]261<div class="doc_text">
262
263<p>An exciting aspect of LLVM is that it is used as an enabling technology for
264 a lot of other language and tools projects. This section lists some of the
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]265 projects that have already been updated to work with LLVM 2.9.</p>
Chris Lattnerdf85c892010-04-26 17:38:10 +0000[diff] [blame]266</div>
267
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]268
269
Chris Lattnerca7c8962010-10-01 06:34:49 +0000[diff] [blame]270
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]271<!-- *********************************************************************** -->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]272<h1>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]273 <a name="whatsnew">What's New in LLVM 2.9?</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]274</h1>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]275<!-- *********************************************************************** -->
276
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]277<div class="doc_text">
278
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]279<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]280minor improvements. Some of the major improvements and new features are listed
281in this section.
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]282</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]283
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]284</div>
285
286<!--=========================================================================-->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]287<h2>
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]288<a name="majorfeatures">Major New Features</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]289</h2>
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]290
291<div class="doc_text">
292
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]293<p>LLVM 2.9 includes several major new capabilities:</p>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]294
295<ul>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]296
297<li>
298 TBAA: On by default in clang. Disable it with -fno-strict-aliasing.
Chris Lattner9ee0b012011-04-05 18:38:45 +0000[diff] [blame]299 Could be more aggressive for structs.
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]300</li>
301
302<li>New Nvidia PTX backend, not generally useful in 2.9 though.</li>
Chris Lattner9ee0b012011-04-05 18:38:45 +0000[diff] [blame]303
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]304<li>
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]305Much better debug info generated, particularly in optimized code situations.
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]306</li>
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]307
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]308<li>
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]309inline asm multiple alternative constraint support.
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]310</li>
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]311
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]312<li>
313 New naming rules in coding standards: CodingStandards.html#ll_naming
314</li>
Chris Lattner269ef9f2011-04-05 21:37:08 +0000[diff] [blame]315
Chris Lattner458e79f2008-02-10 08:18:42 +0000[diff] [blame]316</ul>
Chris Lattnerfd97b882011-04-05 07:19:28 +0000[diff] [blame]317
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]318</div>
319
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]320<!--=========================================================================-->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]321<h2>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]322<a name="coreimprovements">LLVM IR and Core Improvements</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]323</h2>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]324
325<div class="doc_text">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]326<p>LLVM IR has several new features for better support of new targets and that
327expose new optimization opportunities:</p>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]328
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]329<ul>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]330<li>udiv, ashr, lshr, shl now have exact and nuw/nsw bits:
331 PR8862 / LangRef.html</li>
332
333 unnamed_addr + PR8927
334
335 new 'hotpatch' attribute: LangRef.html#fnattrs
336
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]337</ul>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]338
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]339</div>
340
341<!--=========================================================================-->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]342<h2>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]343<a name="optimizer">Optimizer Improvements</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]344</h2>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]345
346<div class="doc_text">
347
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]348<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattner25879d72008-10-13 21:50:36 +0000[diff] [blame]349release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]350
351<ul>
Rafael Espindola01fb4b02011-03-18 04:07:44 +0000[diff] [blame]352 <li>LTO has been improved to use MC for parsing inline asm and now
353 can build large programs like Firefox 4 on both OS X and Linux.</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]354
355
356 LoopIdiom: memset/memcpy formation and memset_pattern on darwin. Build with
357 -ffreestanding or -fno-builtin if your memcpy is being compiled into infinite
358 recursion.
359
360 TargetLibraryInfo
361
362 EarlyCSE pass.
363 LoopInstSimplify pass.
364
365New <a href="WritingAnLLVMPass.html#RegionPass">RegionPass</a> infrastructure
366 for region-based optimizations.
367
368 Can optimize printf to iprintf when no floating point is used, for embedded
369 targets with smaller iprintf implementation.
370
371Speedups to various mid-level passes:
372 GVN is much faster on functions with deep dominator trees / lots of BBs.
373 DomTree and DominatorFrontier are much faster to compute, and preserved by
374 more passes (so they are computed less often)
375 SRoA is also much faster and doesn't use DominanceFrontier.
376
377DSE is more aggressive with stores of different types: e.g. a large store
378 following a small one to the same address.
379
380
381We now optimize various idioms for overflow detection into check of the flag
382 register on various CPUs, e.g.:
383 unsigned long t = a+b;
384 if (t &lt; a) ...
385 into:
386 addq %rdi, %rbx
387 jno LBB0_2
388
389
Chris Lattnerfcc65a72010-10-04 02:42:39 +0000[diff] [blame]390</ul>
391
392<!--
393<p>In addition to these features that are done in 2.8, there is preliminary
394 support in the release for Type Based Alias Analysis
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]395 Preliminary work on TBAA but not usable in 2.8.
396 New CorrelatedValuePropagation pass, not on by default in 2.8 yet.
Chris Lattnerfcc65a72010-10-04 02:42:39 +0000[diff] [blame]397-->
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]398
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]399</div>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]400
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]401<!--=========================================================================-->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]402<h2>
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]403<a name="mc">MC Level Improvements</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]404</h2>
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]405
406<div class="doc_text">
407<p>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]408The LLVM Machine Code (aka MC) subsystem was created to solve a number
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]409of problems in the realm of assembly, disassembly, object file format handling,
410and a number of other related areas that CPU instruction-set level tools work
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]411in.</p>
412
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]413<ul>
Rafael Espindola01fb4b02011-03-18 04:07:44 +0000[diff] [blame]414 <li>MC is now used by default for ELF systems on x86 and
415 x86-64.</li>
416 <li>MC supports and CodeGen uses the <tt>.loc</tt> directives for
417 producing line number debug info. This produces more compact line
418 tables.</li>
419 <li>MC supports the <tt>.cfi_*</tt> directives for producing DWARF
420 frame information, but it is still not used by CodeGen by default.</li>
421 <li>COFF support?</li>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]422
423
424 MC Assembler: X86 now generates much better diagnostics for common errors,
425 is much faster at matching instructions, is much more bug-compatible with
426 the GAS assembler, and is now generally useful for a broad range of X86
427 assembly.
428
429
430 ELF MC support: on by default in clang. There are still known missing features
431 for human written assembly.
432
433
434 Some basic <a href="CodeGenerator.html#mc">internals documentation</a> for MC.
435
436 MC Assembler support for .file and .loc.
437
438 tblgen support for assembler aliases: <a
439 href="CodeGenerator.html#na_instparsing">MnemonicAlias and InstAlias</a>
440
441 Win32 PE-COFF support in the MC assembler has made a lot of progress in the 2.9
442 timeframe, but is still not generally useful. Please see
443 "http://llvm.org/bugs/showdependencytree.cgi?id=9100&amp;hide_resolved=1" for open bugs?
444
445
446 lib/Object and llvm-objdump
447 Experimental format independent object file manipulation library.
448 * Supports PE/COFF and ELF.
449 * llvm-nm extended to work with object files. Exactly matches
450 binutils-nm for the files I've tested.
451 * llvm-objdump added with support for disassembly (no relocations displayed).
452
453
454
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]455</ul>
456
457<p>For more information, please see the <a
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]458href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
459LLVM MC Project Blog Post</a>.
460</p>
461
NAKAMURA Takumi8d89b8e2011-04-05 08:24:22 +0000[diff] [blame]462</div>
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]463
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]464<!--=========================================================================-->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]465<h2>
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]466<a name="codegen">Target Independent Code Generator Improvements</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]467</h2>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]468
469<div class="doc_text">
470
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]471<p>We have put a significant amount of work into the code generator
472infrastructure, which allows us to implement more aggressive algorithms and make
473it run faster:</p>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]474
475<ul>
Chris Lattner9fd1e922010-10-04 03:58:12 +0000[diff] [blame]476<!-- SplitKit -->
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]477
478<li>The pre-register-allocation (preRA) instruction scheduler models register
479 pressure much more accurately in some cases. This allows the adoption of more
480 aggressive scheduling heuristics.
481</li>
482
483 LiveDebugVariables is a new pass that keeps track of debugging information for
484 user variables that are kept in registers in optimized builds.
485
486
487Scheduler now models operand latency and pipeline forwarding.
488
489Major regalloc rewrite, not on by default for 2.9 and not advised to use it.
490 * New basic register allocator that can be used as a safe fallback when
491 debugging. Enable with -regalloc=basic.
492 * New infrastructure for live range splitting. SplitKit can break a live
493 interval into smaller pieces while preserving SSA form, and SpillPlacement
494 can help find the best split points. This is a work in progress so the API
495 is changing quickly.
496 * The inline spiller has learned to clean up after live range splitting. It
497 can hoist spills out of loops, and it can eliminate redundant spills.
498 Rematerialization works with live range splitting.
499 * New greedy register allocator using live range splitting. This will be the
500 default register allocator in the next LLVM release, but it is not turned on
501 by default in 2.9.
502
503
504
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]505</ul>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]506</div>
507
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]508<!--=========================================================================-->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]509<h2>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]510<a name="x86">X86-32 and X86-64 Target Improvements</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]511</h2>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]512
513<div class="doc_text">
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]514<p>New features and major changes in the X86 target include:
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]515</p>
516
517<ul>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]518<li>
519X86: Reimplemented all of MMX to introduce a new LLVM IR x86_mmx type. Now
520 random types like &lt;2 x i32&gt; are not iseld to mmx without emms. The
521 -disable-mmx flag is gone now.
522</li>
523
524 <li>
525X86 support for FS/GS relative loads and stores using address space 256/257 are
526 reliable now.
527 </li>
528
529 <li>
530X86: Much better codegen for several cases using adc/sbb instead of cmovs for
531 conditional increment and other idioms.
532 </li>
533
534 <li>
535 The X86 backend has adopted a new preRA scheduling
536 mode, "list-ilp", to shorten the height of instruction schedules
537 without inducing register spills.
538 </li>
539
540 MC assembler support for 3dNow! and 3DNowA instructions.
541
NAKAMURA Takumi8d89b8e2011-04-05 08:24:22 +0000[diff] [blame]542 <li>Several bugs have been fixed for Windows x64 code generator.</li>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]543</ul>
544
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]545</div>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]546
547<!--=========================================================================-->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]548<h2>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]549<a name="ARM">ARM Target Improvements</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]550</h2>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]551
552<div class="doc_text">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]553<p>New features of the ARM target include:
554</p>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]555
556<ul>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]557<li>ARM Fast ISel</li>
558<li>ARM: New code placement pass.</li>
559<li>ARM: Improved code generation for Cortex-A8 and Cortex-A9 CPUs.</li>
560<li>ARM: __builtin_prefetch turns into prefetch instructions.</li>
561<li>Countless ARM microoptimizations.</li>
562
563<li> The ARM backend preRA scheduler now models machine resources at cycle
564 granularity. This allows the scheduler to both accurately model
565 instruction latency and avoid overcommitting functional units.</li>
566
567
Bob Wilsone44f2982010-09-13 17:39:35 +0000[diff] [blame]568</ul>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]569</div>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]570
571<!--=========================================================================-->
572<h2>
573<a name="OtherTS">Other Target Specific Improvements</a>
574</h2>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]575
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]576<div class="doc_text">
577<ul>
578 PPC: Switched to MCInstPrinter, and MCCodeEmitter. Ready to implement support
579 for directly writing out mach-o object files, but noone seems interested.
580
581 MicroBlaze: major updates for aggressive delay slot filler, MC-based assembly
582 printing, assembly instruction parsing, ELF .o file emission, and MC
583 instruction disassembler.
584
585 SPARC: Many improvements, including using the Y registers for multiplications
586 and addition of a simple delay slot filler.
587
588</ul>
589</div>
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]590
591<!--=========================================================================-->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]592<h2>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]593<a name="changes">Major Changes and Removed Features</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]594</h2>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]595
596<div class="doc_text">
597
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]598<p>If you're already an LLVM user or developer with out-of-tree changes based
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]599on LLVM 2.8, this section lists some "gotchas" that you may run into upgrading
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]600from the previous release.</p>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]601
602<ul>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]603 last release for llvm-gcc
604
605- DIBuilder provides simpler interface for front ends like Clang to encode debug info in LLVM IR.
606 - This interface hides implementation details (e.g. DIDerivedType, existence of compile unit etc..) that any front end should not know about.
607 For example, DIFactory DebugFactory;
608 Ty = DebugFactory.CreateDerivedType(DW_TAG_volatile_type,
609 findRegion(TYPE_CONTEXT(type)),
610 StringRef(),
611 getOrCreateFile(main_input_filename),
612 0 /*line no*/,
613 NodeSizeInBits(type),
614 NodeAlignInBits(type),
615 0 /*offset */,
616 0 /* flags */,
617 MainTy);
618 can be replaced by
619 DbgTy = DBuilder.createQualifiedType(DW_TAG_volatile_type, MainTy);
620DIFactory is gone now.
621
622
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]623
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]624
625
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]626
627 LoopIndexSplit pass was removed, unmaintained.
628 LiveValues, SimplifyHalfPowrLibCalls, and GEPSplitter were removed.
629 Removed the PartialSpecialization pass, it was unmaintained and buggy.
630
631 DIFactory removed, use DIBuilder instead.
632
633 Triple::normalize is new, llvm triples are always stored in normalized form internally.
634
635 Triple x86_64--mingw64 is obsoleted. Use x86_64--mingw32 instead.
636
637 PointerTracking has been removed from mainline, moved to ClamAV.
638
Devang Pateldbf83832008-10-14 20:03:43 +0000[diff] [blame]639</ul>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]640
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]641</div>
642
Daniel Dunbarf70898a2010-10-04 20:11:41 +0000[diff] [blame]643<!--=========================================================================-->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]644<h2>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]645<a name="api_changes">Internal API Changes</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]646</h2>
Daniel Dunbarf70898a2010-10-04 20:11:41 +0000[diff] [blame]647
648<div class="doc_text">
649
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]650<p>In addition, many APIs have changed in this release. Some of the major
651 LLVM API changes are:</p>
Daniel Dunbarf70898a2010-10-04 20:11:41 +0000[diff] [blame]652
653<ul>
Chris Lattnerc3a2c982011-04-06 00:45:11 +0000[diff] [blame^]654
655 include/llvm/System merged into include/llvm/Support.
656
657
658 APInt API changes, see PR5207.
659
660 MVT::Flag renamed to MVT::Glue
661
662
663 error_code + libsystem + PathV2 changes
664 The system_error header from C++0x was added.
665 * Use if (error_code ec = function()) to check for error conditions
666 from functions which return it.
667 * error_code::message returns a human readable description of the error.
668
669 PathV1 has been deprecated in favor of PathV2 (sorry I didn't finish
670 this before the release).
671 * No Path class, use a r-value convertible to a twine instead.
672 * Assumes all paths are UTF-8.
673
674
Daniel Dunbarf70898a2010-10-04 20:11:41 +0000[diff] [blame]675</ul>
676</div>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]677
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]678<!-- *********************************************************************** -->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]679<h1>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]680 <a name="knownproblems">Known Problems</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]681</h1>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]682<!-- *********************************************************************** -->
683
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]684<div class="doc_text">
685
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]686<p>This section contains significant known problems with the LLVM system,
Chris Lattner2a092392008-11-10 05:40:34 +0000[diff] [blame]687listed by component. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]688href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]689there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]690
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]691</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]692
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]693<!-- ======================================================================= -->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]694<h2>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]695 <a name="experimental">Experimental features included with this release</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]696</h2>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]697
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]698<div class="doc_text">
699
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]700<p>The following components of this LLVM release are either untested, known to
701be broken or unreliable, or are in early development. These components should
702not be relied on, and bugs should not be filed against them, but they may be
703useful to some people. In particular, if you would like to work on one of these
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]704components, please contact us on the <a
705href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]706
707<ul>
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]708<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, PTX, SystemZ
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]709 and XCore backends are experimental.</li>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]710<li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets
Chris Lattner0d364302011-03-10 07:43:44 +0000[diff] [blame]711 other than darwin-i386 and darwin-x86_64. FIXME: Not true on ELF anymore?</li>
712
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]713</ul>
714
715</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]716
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]717<!-- ======================================================================= -->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]718<h2>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]719 <a name="x86-be">Known problems with the X86 back-end</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]720</h2>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]721
722<div class="doc_text">
723
724<ul>
Anton Korobeynikov486c7d32008-06-08 10:24:13 +0000[diff] [blame]725 <li>The X86 backend does not yet support
726 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
727 floating point stack</a>. It supports the 'f' and 't' constraints, but not
728 'u'.</li>
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]729 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]730 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]731 argument constructs on X86-64 by lowering them manually.</li>
NAKAMURA Takumi8d89b8e2011-04-05 08:24:22 +0000[diff] [blame]732 <li>Windows x64 (aka Win64) code generator has a few issues.
733 <ul>
734 <li>llvm-gcc cannot build the mingw-w64 runtime currently
735 due to lack of support for the 'u' inline assembly
736 constraint and for X87 floating point inline assembly.</li>
737 <li>On mingw-w64, you will see unresolved symbol <tt>__chkstk</tt>
738 due to <a href="http://llvm.org/bugs/show_bug.cgi?id=8919">Bug 8919</a>.
739 It is fixed in <a href="http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20110321/118499.html">r128206</a>.</li>
740 <li>Miss-aligned MOVDQA might crash your program. It is due to
741 <a href="http://llvm.org/bugs/show_bug.cgi?id=9483">Bug 9483</a>,
742 lack of handling aligned internal globals.</li>
743 </ul>
744 </li>
745
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]746</ul>
747
748</div>
749
750<!-- ======================================================================= -->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]751<h2>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]752 <a name="ppc-be">Known problems with the PowerPC back-end</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]753</h2>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]754
755<div class="doc_text">
756
757<ul>
Nicolas Geoffray77d99502007-05-15 09:21:28 +0000[diff] [blame]758<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]759compilation, and lacks support for debug information.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]760</ul>
761
762</div>
763
764<!-- ======================================================================= -->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]765<h2>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]766 <a name="arm-be">Known problems with the ARM back-end</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]767</h2>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]768
769<div class="doc_text">
770
771<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]772<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands47fc0a22007-09-26 15:59:54 +0000[diff] [blame]773processors, thumb programs can crash or produce wrong
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]774results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]775<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]776</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]777</ul>
778
779</div>
780
781<!-- ======================================================================= -->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]782<h2>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]783 <a name="sparc-be">Known problems with the SPARC back-end</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]784</h2>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]785
786<div class="doc_text">
787
788<ul>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]789<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]790 support the 64-bit SPARC ABI (-m64).</li>
791</ul>
792
793</div>
794
795<!-- ======================================================================= -->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]796<h2>
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]797 <a name="mips-be">Known problems with the MIPS back-end</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]798</h2>
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]799
800<div class="doc_text">
801
802<ul>
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]803<li>64-bit MIPS targets are not supported yet.</li>
804</ul>
805
806</div>
807
808<!-- ======================================================================= -->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]809<h2>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]810 <a name="alpha-be">Known problems with the Alpha back-end</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]811</h2>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]812
813<div class="doc_text">
814
815<ul>
816
817<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
818appropriate nops inserted to ensure restartability.</li>
819
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]820</ul>
821</div>
822
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]823<!-- ======================================================================= -->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]824<h2>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]825 <a name="c-be">Known problems with the C back-end</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]826</h2>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]827
828<div class="doc_text">
829
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]830<p>The C backend has numerous problems and is not being actively maintained.
831Depending on it for anything serious is not advised.</p>
832
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]833<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]834<li><a href="http://llvm.org/PR802">The C backend has only basic support for
835 inline assembly code</a>.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000[diff] [blame]836<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
837 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif75b2f762009-03-02 12:02:51 +0000[diff] [blame]838 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandse09506a2008-02-10 13:40:55 +0000[diff] [blame]839<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands3aa36732009-02-25 11:51:54 +0000[diff] [blame]840<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]841</ul>
842
843</div>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]844
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]845
846<!-- ======================================================================= -->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]847<h2>
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]848 <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]849</h2>
Chris Lattner178f3db2003-10-02 05:07:23 +0000[diff] [blame]850
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]851<div class="doc_text">
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]852
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]853<p>llvm-gcc is generally very stable for the C family of languages. The only
854 major language feature of GCC not supported by llvm-gcc is the
855 <tt>__builtin_apply</tt> family of builtins. However, some extensions
856 are only supported on some targets. For example, trampolines are only
857 supported on some targets (these are used when you take the address of a
858 nested function).</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]859
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]860<p>Fortran support generally works, but there are still several unresolved bugs
861 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
862 tools/gfortran component for details. Note that llvm-gcc is missing major
863 Fortran performance work in the frontend and library that went into GCC after
864 4.2. If you are interested in Fortran, we recommend that you consider using
865 <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]866
Duncan Sandsd63e1c82010-10-04 10:06:56 +0000[diff] [blame]867<p>The llvm-gcc 4.2 Ada compiler has basic functionality, but is no longer being
868actively maintained. If you are interested in Ada, we recommend that you
869consider using <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]870</div>
871
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]872<!-- *********************************************************************** -->
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]873<h1>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]874 <a name="additionalinfo">Additional Information</a>
NAKAMURA Takumi530d7392011-04-05 21:55:14 +0000[diff] [blame]875</h1>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]876<!-- *********************************************************************** -->
877
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]878<div class="doc_text">
879
Chris Lattnercb5596d2005-05-16 17:13:10 +0000[diff] [blame]880<p>A wide variety of additional information is available on the <a
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]881href="http://llvm.org">LLVM web page</a>, in particular in the <a
882href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]883contains versions of the API documentation which is up-to-date with the
884Subversion version of the source code.
Misha Brukman96158092005-03-30 19:14:24 +0000[diff] [blame]885You can access versions of these documents specific to this release by going
886into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]887
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]888<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]889us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]890lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]891
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]892</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]893
894<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]895
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]896<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]897<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000[diff] [blame]898 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]899 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]900 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]901 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]902
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]903 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]904 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]905</address>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]906
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]907</body>
908</html>