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Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]8 <title>LLVM 2.9 Release Notes</title>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]9</head>
10<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]11
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]12<h1 class="doc_title">LLVM 2.9 Release Notes</h1>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]13
Chris Lattner0e464a92010-03-17 04:02:39 +0000[diff] [blame]14<img align=right src="http://llvm.org/img/DragonSmall.png"
Gabor Greifee2187a2010-04-22 10:21:43 +0000[diff] [blame]15 width="136" height="136" alt="LLVM Dragon Logo">
Chris Lattner0e464a92010-03-17 04:02:39 +0000[diff] [blame]16
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]17<ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]18 <li><a href="#intro">Introduction</a></li>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]19 <li><a href="#subproj">Sub-project Status Update</a></li>
Chris Lattnerbe2e1b52011-03-10 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 Lattner4b538b92004-04-30 22:17:12 +0000[diff] [blame]22 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Dan Gohman44aa9212008-10-14 16:23:02 +0000[diff] [blame]23 <li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]24 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]25</ol>
26
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]27<div class="doc_author">
Dan Gohman44aa9212008-10-14 16:23:02 +0000[diff] [blame]28 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]29</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]30
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]31<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.9
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]32release.<br>
33You may prefer the
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]34<a href="http://llvm.org/releases/2.8/docs/ReleaseNotes.html">LLVM 2.8
Dan Gohmanb44f6c62010-05-03 23:51:05 +0000[diff] [blame]35Release Notes</a>.</h1>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]36
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]37<!-- *********************************************************************** -->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]38<h1>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]39 <a name="intro">Introduction</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]40</h1>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]41<!-- *********************************************************************** -->
42
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]43<div class="doc_text">
44
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]45<p>This document contains the release notes for the LLVM Compiler
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]46Infrastructure, release 2.9. Here we describe the status of LLVM, including
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]47major improvements from the previous release and significant known problems.
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]48All LLVM releases may be downloaded from the <a
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]49href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]50
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]51<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]52release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]53web site</a>. If you have questions or comments, the <a
Chris Lattnerc66bfef2010-03-17 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 Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]56
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]57<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]58main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greiffa933f82008-10-14 11:00:32 +0000[diff] [blame]59current one. To see the release notes for a specific release, please see the
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]60<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]61
62</div>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]63
Chris Lattnere4dc1962011-04-05 23:22:33 +0000[diff] [blame]64<!-- Features that need text if they're finished for 3.1:
65 ARM EHABI
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]66 combiner-aa?
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]67 strong phi elim
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]68 loop dependence analysis
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]69 CorrelatedValuePropagation
Chris Lattnere4dc1962011-04-05 23:22:33 +0000[diff] [blame]70 lib/Transforms/IPO/MergeFunctions.cpp => consider for 3.1.
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]71 -->
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]72
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]73<!-- *********************************************************************** -->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]74<h1>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]75 <a name="subproj">Sub-project Status Update</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]76</h1>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]77<!-- *********************************************************************** -->
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]78
79<div class="doc_text">
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]80<p>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]81The LLVM 2.9 distribution currently consists of code from the core LLVM
Chris Lattner61358ab2009-10-13 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 Wendling63d8c552009-03-02 04:28:57 +0000[diff] [blame]86</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]87
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]88</div>
89
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]90
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]91<!--=========================================================================-->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]92<h2>
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000[diff] [blame]93<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]94</h2>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]95
96<div class="doc_text">
97
Chris Lattner095539f2010-04-26 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 Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]104production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]105(32- and 64-bit), and for darwin/arm targets.</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]106
Chris Lattner0a6f6d52011-04-05 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
Chris Lattnerdf448a32011-04-06 00:56:12 +0000[diff] [blame]109been exercised on a broad variety of code, and has several new <a
110href="http://clang.llvm.org/cxx_status.html#cxx0x">C++'0x features</a>
Chris Lattner0a6f6d52011-04-05 07:19:28 +0000[diff] [blame]111implemented (such as rvalue references and variadic templates). LLVM 2.9 has
112also brought in a large range of bug fixes and minor features (e.g. __label__
113support), and is much more compatible with the Linux Kernel.</p>
114
115<p>If Clang rejects your code that is built with another compiler, please take a
116look at the <a href="http://clang.llvm.org/compatibility.html">language
117compatibility</a> guide to make sure the issue isn't intentional or a known
118issue.
119</p>
Bill Wendling741748a2008-10-27 09:27:33 +0000[diff] [blame]120
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]121<ul>
122</ul>
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000[diff] [blame]123</div>
124
125<!--=========================================================================-->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]126<h2>
Duncan Sands528a5102011-04-04 11:09:08 +0000[diff] [blame]127<a name="dragonegg">DragonEgg: GCC front-ends, LLVM back-end</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]128</h2>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]129
130<div class="doc_text">
131<p>
Duncan Sands528a5102011-04-04 11:09:08 +0000[diff] [blame]132<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a
133<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin</a> that replaces GCC's
134optimizers and code generators with LLVM's.
135Currently it requires a patched version of gcc-4.5.
136The plugin can target the x86-32 and x86-64 processor families and has been
137used successfully on the Darwin, FreeBSD and Linux platforms.
138The Ada, C, C++ and Fortran languages work well.
139The plugin is capable of compiling plenty of Obj-C, Obj-C++ and Java but it is
140not known whether the compiled code actually works or not!
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]141</p>
142
143<p>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]144The 2.9 release has the following notable changes:
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000[diff] [blame]145<ul>
Duncan Sands528a5102011-04-04 11:09:08 +0000[diff] [blame]146<li>The plugin is much more stable when compiling Fortran.</li>
Chris Lattnerdf448a32011-04-06 00:56:12 +0000[diff] [blame]147<li>Inline assembly where an asm output is tied to an input of a different size
148is now supported in many more cases.</li>
Duncan Sands528a5102011-04-04 11:09:08 +0000[diff] [blame]149<li>Basic support for the __float128 type was added. It is now possible to
150generate LLVM IR from programs using __float128 but code generation does not
151work yet.</li>
152<li>Compiling Java programs no longer systematically crashes the plugin.</li>
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000[diff] [blame]153</ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]154
155</div>
156
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]157<!--=========================================================================-->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]158<h2>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]159<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]160</h2>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]161
162<div class="doc_text">
163<p>
164The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
165is a simple library that provides an implementation of the low-level
166target-specific hooks required by code generation and other runtime components.
167For example, when compiling for a 32-bit target, converting a double to a 64-bit
168unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
169function. The compiler-rt library provides highly optimized implementations of
170this and other low-level routines (some are 3x faster than the equivalent
171libgcc routines).</p>
172
Chris Lattnerdf448a32011-04-06 00:56:12 +0000[diff] [blame]173<p>In the LLVM 2.9 timeframe, compiler_rt has had several minor changes for
174 better ARM support, and a fairly major license change. All of the code in the
175 compiler-rt project is now <a href="DeveloperPolicy.html#license">dual
176 licensed</a> under MIT and UIUC license, which allows you to use compiler-rt
177 in applications without the binary copyright reproduction clause. If you
178 prefer the LLVM/UIUC license, you are free to continue using it under that
179 license as well.</p>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]180
181</div>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]182
183<!--=========================================================================-->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]184<h2>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]185<a name="lldb">LLDB: Low Level Debugger</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]186</h2>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]187
188<div class="doc_text">
189<p>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]190<a href="http://lldb.llvm.org/">LLDB</a> is a brand new member of the LLVM
191umbrella of projects. LLDB is a next generation, high-performance debugger. It
192is built as a set of reusable components which highly leverage existing
193libraries in the larger LLVM Project, such as the Clang expression parser, the
194LLVM disassembler and the LLVM JIT.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]195
196<p>
Chris Lattnerdf448a32011-04-06 00:56:12 +0000[diff] [blame]197LLDB is has advanced by leaps and bounds in the 2.9 timeframe. It is
198dramatically more stable and useful, and includes both a new <a
199href="http://lldb.llvm.org/tutorial.html">tutorial</a> and a <a
200href="http://lldb.llvm.org/lldb-gdb.html">side-by-side comparison with
201GDB</a>.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]202
203</div>
204
205<!--=========================================================================-->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]206<h2>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]207<a name="libc++">libc++: C++ Standard Library</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]208</h2>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]209
210<div class="doc_text">
211<p>
Tobias Grossercdce44b2010-10-06 21:07:30 +0000[diff] [blame]212<a href="http://libcxx.llvm.org/">libc++</a> is another new member of the LLVM
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]213family. It is an implementation of the C++ standard library, written from the
214ground up to specifically target the forthcoming C++'0X standard and focus on
215delivering great performance.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]216
217<p>
Chris Lattner2009c492011-04-06 00:59:18 +0000[diff] [blame]218In the LLVM 2.9 timeframe, libc++ has had numerous bugs fixed, and is now being
219co-developed with Clang's C++'0x mode.</p>
Chris Lattner0a6f6d52011-04-05 07:19:28 +0000[diff] [blame]220
Chris Lattner2009c492011-04-06 00:59:18 +0000[diff] [blame]221<p>
222Like compiler_rt, libc++ is now <a href="DeveloperPolicy.html#license">dual
223 licensed</a> under the MIT and UIUC license, allowing it to be used more
224 permissively.
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]225</p>
226
227</div>
228
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]229
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000[diff] [blame]230
231<!--=========================================================================-->
Chris Lattner7a8e6c52011-04-05 18:38:45 +0000[diff] [blame]232<!--
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]233<h2>
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000[diff] [blame]234<a name="klee">KLEE: A Symbolic Execution Virtual Machine</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]235</h2>
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000[diff] [blame]236
237<div class="doc_text">
238<p>
239<a href="http://klee.llvm.org/">KLEE</a> is a symbolic execution framework for
240programs in LLVM bitcode form. KLEE tries to symbolically evaluate "all" paths
241through the application and records state transitions that lead to fault
242states. This allows it to construct testcases that lead to faults and can even
243be used to verify some algorithms.
244</p>
245
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]246<p>UPDATE!</p>
Chris Lattner7a8e6c52011-04-05 18:38:45 +0000[diff] [blame]247</div>-->
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000[diff] [blame]248
249
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]250<!-- *********************************************************************** -->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]251<h1>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]252 <a name="externalproj">External Open Source Projects Using LLVM 2.9</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]253</h1>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]254<!-- *********************************************************************** -->
255
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]256<div class="doc_text">
257
258<p>An exciting aspect of LLVM is that it is used as an enabling technology for
259 a lot of other language and tools projects. This section lists some of the
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]260 projects that have already been updated to work with LLVM 2.9.</p>
Chris Lattner7c8e7962010-04-26 17:38:10 +0000[diff] [blame]261</div>
262
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]263
264
Chris Lattnere0518442010-10-01 06:34:49 +0000[diff] [blame]265
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]266<!-- *********************************************************************** -->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]267<h1>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]268 <a name="whatsnew">What's New in LLVM 2.9?</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]269</h1>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]270<!-- *********************************************************************** -->
271
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]272<div class="doc_text">
273
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]274<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]275minor improvements. Some of the major improvements and new features are listed
276in this section.
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]277</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]278
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]279</div>
280
281<!--=========================================================================-->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]282<h2>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]283<a name="majorfeatures">Major New Features</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]284</h2>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]285
286<div class="doc_text">
287
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]288<p>LLVM 2.9 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]289
290<ul>
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]291
292<li>
293 TBAA: On by default in clang. Disable it with -fno-strict-aliasing.
Chris Lattner7a8e6c52011-04-05 18:38:45 +0000[diff] [blame]294 Could be more aggressive for structs.
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]295</li>
296
297<li>New Nvidia PTX backend, not generally useful in 2.9 though.</li>
Chris Lattner7a8e6c52011-04-05 18:38:45 +0000[diff] [blame]298
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]299<li>
Chris Lattner0a6f6d52011-04-05 07:19:28 +0000[diff] [blame]300Much better debug info generated, particularly in optimized code situations.
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]301</li>
Chris Lattner0a6f6d52011-04-05 07:19:28 +0000[diff] [blame]302
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]303<li>
Chris Lattner0a6f6d52011-04-05 07:19:28 +0000[diff] [blame]304inline asm multiple alternative constraint support.
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]305</li>
Chris Lattner0a6f6d52011-04-05 07:19:28 +0000[diff] [blame]306
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]307<li>
308 New naming rules in coding standards: CodingStandards.html#ll_naming
309</li>
Chris Lattner0f310ee2011-04-05 21:37:08 +0000[diff] [blame]310
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]311</ul>
Chris Lattner0a6f6d52011-04-05 07:19:28 +0000[diff] [blame]312
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]313</div>
314
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]315<!--=========================================================================-->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]316<h2>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]317<a name="coreimprovements">LLVM IR and Core Improvements</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]318</h2>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]319
320<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]321<p>LLVM IR has several new features for better support of new targets and that
322expose new optimization opportunities:</p>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]323
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]324<ul>
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]325<li>udiv, ashr, lshr, shl now have exact and nuw/nsw bits:
326 PR8862 / LangRef.html</li>
327
328 unnamed_addr + PR8927
329
330 new 'hotpatch' attribute: LangRef.html#fnattrs
331
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]332</ul>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]333
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]334</div>
335
336<!--=========================================================================-->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]337<h2>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]338<a name="optimizer">Optimizer Improvements</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]339</h2>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]340
341<div class="doc_text">
342
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]343<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattnerf3013872008-10-13 21:50:36 +0000[diff] [blame]344release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]345
346<ul>
Rafael Espindolaa26f36c2011-03-18 04:07:44 +0000[diff] [blame]347 <li>LTO has been improved to use MC for parsing inline asm and now
348 can build large programs like Firefox 4 on both OS X and Linux.</li>
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]349
350
351 LoopIdiom: memset/memcpy formation and memset_pattern on darwin. Build with
352 -ffreestanding or -fno-builtin if your memcpy is being compiled into infinite
353 recursion.
354
355 TargetLibraryInfo
356
357 EarlyCSE pass.
358 LoopInstSimplify pass.
359
360New <a href="WritingAnLLVMPass.html#RegionPass">RegionPass</a> infrastructure
361 for region-based optimizations.
362
363 Can optimize printf to iprintf when no floating point is used, for embedded
364 targets with smaller iprintf implementation.
365
366Speedups to various mid-level passes:
367 GVN is much faster on functions with deep dominator trees / lots of BBs.
368 DomTree and DominatorFrontier are much faster to compute, and preserved by
369 more passes (so they are computed less often)
370 SRoA is also much faster and doesn't use DominanceFrontier.
371
372DSE is more aggressive with stores of different types: e.g. a large store
373 following a small one to the same address.
374
375
376We now optimize various idioms for overflow detection into check of the flag
377 register on various CPUs, e.g.:
378 unsigned long t = a+b;
379 if (t &lt; a) ...
380 into:
381 addq %rdi, %rbx
382 jno LBB0_2
383
384
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]385</ul>
386
387<!--
388<p>In addition to these features that are done in 2.8, there is preliminary
389 support in the release for Type Based Alias Analysis
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]390 Preliminary work on TBAA but not usable in 2.8.
391 New CorrelatedValuePropagation pass, not on by default in 2.8 yet.
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]392-->
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]393
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]394</div>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]395
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]396<!--=========================================================================-->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]397<h2>
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]398<a name="mc">MC Level Improvements</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]399</h2>
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]400
401<div class="doc_text">
402<p>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]403The LLVM Machine Code (aka MC) subsystem was created to solve a number
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]404of problems in the realm of assembly, disassembly, object file format handling,
405and a number of other related areas that CPU instruction-set level tools work
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]406in.</p>
407
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]408<ul>
Rafael Espindolaa26f36c2011-03-18 04:07:44 +0000[diff] [blame]409 <li>MC is now used by default for ELF systems on x86 and
410 x86-64.</li>
411 <li>MC supports and CodeGen uses the <tt>.loc</tt> directives for
412 producing line number debug info. This produces more compact line
413 tables.</li>
414 <li>MC supports the <tt>.cfi_*</tt> directives for producing DWARF
415 frame information, but it is still not used by CodeGen by default.</li>
416 <li>COFF support?</li>
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]417
418
419 MC Assembler: X86 now generates much better diagnostics for common errors,
420 is much faster at matching instructions, is much more bug-compatible with
421 the GAS assembler, and is now generally useful for a broad range of X86
422 assembly.
423
424
425 ELF MC support: on by default in clang. There are still known missing features
426 for human written assembly.
427
428
429 Some basic <a href="CodeGenerator.html#mc">internals documentation</a> for MC.
430
431 MC Assembler support for .file and .loc.
432
433 tblgen support for assembler aliases: <a
434 href="CodeGenerator.html#na_instparsing">MnemonicAlias and InstAlias</a>
435
436 Win32 PE-COFF support in the MC assembler has made a lot of progress in the 2.9
437 timeframe, but is still not generally useful. Please see
438 "http://llvm.org/bugs/showdependencytree.cgi?id=9100&amp;hide_resolved=1" for open bugs?
439
440
441 lib/Object and llvm-objdump
442 Experimental format independent object file manipulation library.
443 * Supports PE/COFF and ELF.
444 * llvm-nm extended to work with object files. Exactly matches
445 binutils-nm for the files I've tested.
446 * llvm-objdump added with support for disassembly (no relocations displayed).
447
448
449
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]450</ul>
451
452<p>For more information, please see the <a
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]453href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
454LLVM MC Project Blog Post</a>.
455</p>
456
NAKAMURA Takumi45c435a2011-04-05 08:24:22 +0000[diff] [blame]457</div>
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]458
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]459<!--=========================================================================-->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]460<h2>
Chris Lattner511433e2009-03-02 03:24:11 +0000[diff] [blame]461<a name="codegen">Target Independent Code Generator Improvements</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]462</h2>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]463
464<div class="doc_text">
465
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]466<p>We have put a significant amount of work into the code generator
467infrastructure, which allows us to implement more aggressive algorithms and make
468it run faster:</p>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]469
470<ul>
Chris Lattner3bdcda12010-10-04 03:58:12 +0000[diff] [blame]471<!-- SplitKit -->
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]472
473<li>The pre-register-allocation (preRA) instruction scheduler models register
474 pressure much more accurately in some cases. This allows the adoption of more
475 aggressive scheduling heuristics.
476</li>
477
478 LiveDebugVariables is a new pass that keeps track of debugging information for
479 user variables that are kept in registers in optimized builds.
480
481
482Scheduler now models operand latency and pipeline forwarding.
483
484Major regalloc rewrite, not on by default for 2.9 and not advised to use it.
485 * New basic register allocator that can be used as a safe fallback when
486 debugging. Enable with -regalloc=basic.
487 * New infrastructure for live range splitting. SplitKit can break a live
488 interval into smaller pieces while preserving SSA form, and SpillPlacement
489 can help find the best split points. This is a work in progress so the API
490 is changing quickly.
491 * The inline spiller has learned to clean up after live range splitting. It
492 can hoist spills out of loops, and it can eliminate redundant spills.
493 Rematerialization works with live range splitting.
494 * New greedy register allocator using live range splitting. This will be the
495 default register allocator in the next LLVM release, but it is not turned on
496 by default in 2.9.
497
498
499
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]500</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]501</div>
502
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]503<!--=========================================================================-->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]504<h2>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]505<a name="x86">X86-32 and X86-64 Target Improvements</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]506</h2>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]507
508<div class="doc_text">
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame]509<p>New features and major changes in the X86 target include:
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]510</p>
511
512<ul>
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]513<li>
514X86: Reimplemented all of MMX to introduce a new LLVM IR x86_mmx type. Now
515 random types like &lt;2 x i32&gt; are not iseld to mmx without emms. The
516 -disable-mmx flag is gone now.
517</li>
518
519 <li>
520X86 support for FS/GS relative loads and stores using address space 256/257 are
521 reliable now.
522 </li>
523
524 <li>
525X86: Much better codegen for several cases using adc/sbb instead of cmovs for
526 conditional increment and other idioms.
527 </li>
528
529 <li>
530 The X86 backend has adopted a new preRA scheduling
531 mode, "list-ilp", to shorten the height of instruction schedules
532 without inducing register spills.
533 </li>
534
535 MC assembler support for 3dNow! and 3DNowA instructions.
536
NAKAMURA Takumi45c435a2011-04-05 08:24:22 +0000[diff] [blame]537 <li>Several bugs have been fixed for Windows x64 code generator.</li>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]538</ul>
539
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]540</div>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]541
542<!--=========================================================================-->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]543<h2>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]544<a name="ARM">ARM Target Improvements</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]545</h2>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]546
547<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]548<p>New features of the ARM target include:
549</p>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]550
551<ul>
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]552<li>ARM Fast ISel</li>
553<li>ARM: New code placement pass.</li>
554<li>ARM: Improved code generation for Cortex-A8 and Cortex-A9 CPUs.</li>
555<li>ARM: __builtin_prefetch turns into prefetch instructions.</li>
556<li>Countless ARM microoptimizations.</li>
557
558<li> The ARM backend preRA scheduler now models machine resources at cycle
559 granularity. This allows the scheduler to both accurately model
560 instruction latency and avoid overcommitting functional units.</li>
561
562
Bob Wilsone8472772010-09-13 17:39:35 +0000[diff] [blame]563</ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]564</div>
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]565
566<!--=========================================================================-->
567<h2>
568<a name="OtherTS">Other Target Specific Improvements</a>
569</h2>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]570
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]571<div class="doc_text">
572<ul>
573 PPC: Switched to MCInstPrinter, and MCCodeEmitter. Ready to implement support
574 for directly writing out mach-o object files, but noone seems interested.
575
576 MicroBlaze: major updates for aggressive delay slot filler, MC-based assembly
577 printing, assembly instruction parsing, ELF .o file emission, and MC
578 instruction disassembler.
579
580 SPARC: Many improvements, including using the Y registers for multiplications
581 and addition of a simple delay slot filler.
582
583</ul>
584</div>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]585
586<!--=========================================================================-->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]587<h2>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]588<a name="changes">Major Changes and Removed Features</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]589</h2>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]590
591<div class="doc_text">
592
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]593<p>If you're already an LLVM user or developer with out-of-tree changes based
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]594on LLVM 2.8, this section lists some "gotchas" that you may run into upgrading
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]595from the previous release.</p>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]596
597<ul>
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]598 last release for llvm-gcc
599
600- DIBuilder provides simpler interface for front ends like Clang to encode debug info in LLVM IR.
601 - This interface hides implementation details (e.g. DIDerivedType, existence of compile unit etc..) that any front end should not know about.
602 For example, DIFactory DebugFactory;
603 Ty = DebugFactory.CreateDerivedType(DW_TAG_volatile_type,
604 findRegion(TYPE_CONTEXT(type)),
605 StringRef(),
606 getOrCreateFile(main_input_filename),
607 0 /*line no*/,
608 NodeSizeInBits(type),
609 NodeAlignInBits(type),
610 0 /*offset */,
611 0 /* flags */,
612 MainTy);
613 can be replaced by
614 DbgTy = DBuilder.createQualifiedType(DW_TAG_volatile_type, MainTy);
615DIFactory is gone now.
616
617
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]618
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]619
620
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]621
622 LoopIndexSplit pass was removed, unmaintained.
623 LiveValues, SimplifyHalfPowrLibCalls, and GEPSplitter were removed.
624 Removed the PartialSpecialization pass, it was unmaintained and buggy.
625
626 DIFactory removed, use DIBuilder instead.
627
628 Triple::normalize is new, llvm triples are always stored in normalized form internally.
629
630 Triple x86_64--mingw64 is obsoleted. Use x86_64--mingw32 instead.
631
632 PointerTracking has been removed from mainline, moved to ClamAV.
633
Devang Patelb34dd132008-10-14 20:03:43 +0000[diff] [blame]634</ul>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]635
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]636</div>
637
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000[diff] [blame]638<!--=========================================================================-->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]639<h2>
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]640<a name="api_changes">Internal API Changes</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]641</h2>
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000[diff] [blame]642
643<div class="doc_text">
644
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]645<p>In addition, many APIs have changed in this release. Some of the major
646 LLVM API changes are:</p>
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000[diff] [blame]647
648<ul>
Chris Lattner1efe27e2011-04-06 00:45:11 +0000[diff] [blame]649
650 include/llvm/System merged into include/llvm/Support.
651
652
653 APInt API changes, see PR5207.
654
655 MVT::Flag renamed to MVT::Glue
656
657
658 error_code + libsystem + PathV2 changes
659 The system_error header from C++0x was added.
660 * Use if (error_code ec = function()) to check for error conditions
661 from functions which return it.
662 * error_code::message returns a human readable description of the error.
663
664 PathV1 has been deprecated in favor of PathV2 (sorry I didn't finish
665 this before the release).
666 * No Path class, use a r-value convertible to a twine instead.
667 * Assumes all paths are UTF-8.
668
669
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000[diff] [blame]670</ul>
671</div>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]672
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]673<!-- *********************************************************************** -->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]674<h1>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]675 <a name="knownproblems">Known Problems</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]676</h1>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]677<!-- *********************************************************************** -->
678
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]679<div class="doc_text">
680
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]681<p>This section contains significant known problems with the LLVM system,
Chris Lattnere18b32e2008-11-10 05:40:34 +0000[diff] [blame]682listed by component. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]683href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]684there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]685
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]686</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]687
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]688<!-- ======================================================================= -->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]689<h2>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]690 <a name="experimental">Experimental features included with this release</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]691</h2>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]692
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]693<div class="doc_text">
694
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]695<p>The following components of this LLVM release are either untested, known to
696be broken or unreliable, or are in early development. These components should
697not be relied on, and bugs should not be filed against them, but they may be
698useful to some people. In particular, if you would like to work on one of these
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]699components, please contact us on the <a
700href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]701
702<ul>
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]703<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, PTX, SystemZ
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]704 and XCore backends are experimental.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]705<li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets
Chris Lattnerbe2e1b52011-03-10 07:43:44 +0000[diff] [blame]706 other than darwin-i386 and darwin-x86_64. FIXME: Not true on ELF anymore?</li>
707
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]708</ul>
709
710</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]711
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]712<!-- ======================================================================= -->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]713<h2>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]714 <a name="x86-be">Known problems with the X86 back-end</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]715</h2>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]716
717<div class="doc_text">
718
719<ul>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]720 <li>The X86 backend does not yet support
721 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
722 floating point stack</a>. It supports the 'f' and 't' constraints, but not
723 'u'.</li>
Dan Gohman8207ba92008-06-08 23:05:11 +0000[diff] [blame]724 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]725 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman8207ba92008-06-08 23:05:11 +0000[diff] [blame]726 argument constructs on X86-64 by lowering them manually.</li>
NAKAMURA Takumi45c435a2011-04-05 08:24:22 +0000[diff] [blame]727 <li>Windows x64 (aka Win64) code generator has a few issues.
728 <ul>
729 <li>llvm-gcc cannot build the mingw-w64 runtime currently
730 due to lack of support for the 'u' inline assembly
731 constraint and for X87 floating point inline assembly.</li>
732 <li>On mingw-w64, you will see unresolved symbol <tt>__chkstk</tt>
733 due to <a href="http://llvm.org/bugs/show_bug.cgi?id=8919">Bug 8919</a>.
734 It is fixed in <a href="http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20110321/118499.html">r128206</a>.</li>
735 <li>Miss-aligned MOVDQA might crash your program. It is due to
736 <a href="http://llvm.org/bugs/show_bug.cgi?id=9483">Bug 9483</a>,
737 lack of handling aligned internal globals.</li>
738 </ul>
739 </li>
740
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]741</ul>
742
743</div>
744
745<!-- ======================================================================= -->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]746<h2>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]747 <a name="ppc-be">Known problems with the PowerPC back-end</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]748</h2>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]749
750<div class="doc_text">
751
752<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000[diff] [blame]753<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]754compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]755</ul>
756
757</div>
758
759<!-- ======================================================================= -->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]760<h2>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]761 <a name="arm-be">Known problems with the ARM back-end</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]762</h2>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]763
764<div class="doc_text">
765
766<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]767<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000[diff] [blame]768processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]769results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]770<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]771</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]772</ul>
773
774</div>
775
776<!-- ======================================================================= -->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]777<h2>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]778 <a name="sparc-be">Known problems with the SPARC back-end</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]779</h2>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]780
781<div class="doc_text">
782
783<ul>
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]784<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]785 support the 64-bit SPARC ABI (-m64).</li>
786</ul>
787
788</div>
789
790<!-- ======================================================================= -->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]791<h2>
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000[diff] [blame]792 <a name="mips-be">Known problems with the MIPS back-end</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]793</h2>
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000[diff] [blame]794
795<div class="doc_text">
796
797<ul>
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000[diff] [blame]798<li>64-bit MIPS targets are not supported yet.</li>
799</ul>
800
801</div>
802
803<!-- ======================================================================= -->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]804<h2>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]805 <a name="alpha-be">Known problems with the Alpha back-end</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]806</h2>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]807
808<div class="doc_text">
809
810<ul>
811
812<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
813appropriate nops inserted to ensure restartability.</li>
814
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]815</ul>
816</div>
817
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]818<!-- ======================================================================= -->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]819<h2>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]820 <a name="c-be">Known problems with the C back-end</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]821</h2>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]822
823<div class="doc_text">
824
Chris Lattner3016ee92010-09-29 05:34:42 +0000[diff] [blame]825<p>The C backend has numerous problems and is not being actively maintained.
826Depending on it for anything serious is not advised.</p>
827
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]828<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]829<li><a href="http://llvm.org/PR802">The C backend has only basic support for
830 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000[diff] [blame]831<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
832 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif4906abe2009-03-02 12:02:51 +0000[diff] [blame]833 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]834<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands50723a92009-02-25 11:51:54 +0000[diff] [blame]835<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]836</ul>
837
838</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]839
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]840
841<!-- ======================================================================= -->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]842<h2>
Chris Lattner3016ee92010-09-29 05:34:42 +0000[diff] [blame]843 <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]844</h2>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]845
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]846<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]847
Chris Lattner3016ee92010-09-29 05:34:42 +0000[diff] [blame]848<p>llvm-gcc is generally very stable for the C family of languages. The only
849 major language feature of GCC not supported by llvm-gcc is the
850 <tt>__builtin_apply</tt> family of builtins. However, some extensions
851 are only supported on some targets. For example, trampolines are only
852 supported on some targets (these are used when you take the address of a
853 nested function).</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]854
Chris Lattner3016ee92010-09-29 05:34:42 +0000[diff] [blame]855<p>Fortran support generally works, but there are still several unresolved bugs
856 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
857 tools/gfortran component for details. Note that llvm-gcc is missing major
858 Fortran performance work in the frontend and library that went into GCC after
859 4.2. If you are interested in Fortran, we recommend that you consider using
860 <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]861
Duncan Sands3af96332010-10-04 10:06:56 +0000[diff] [blame]862<p>The llvm-gcc 4.2 Ada compiler has basic functionality, but is no longer being
863actively maintained. If you are interested in Ada, we recommend that you
864consider using <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]865</div>
866
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]867<!-- *********************************************************************** -->
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]868<h1>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]869 <a name="additionalinfo">Additional Information</a>
NAKAMURA Takumic6319312011-04-05 21:55:14 +0000[diff] [blame]870</h1>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]871<!-- *********************************************************************** -->
872
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]873<div class="doc_text">
874
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]875<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]876href="http://llvm.org">LLVM web page</a>, in particular in the <a
877href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]878contains versions of the API documentation which is up-to-date with the
879Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]880You can access versions of these documents specific to this release by going
881into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]882
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]883<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]884us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]885lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]886
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]887</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]888
889<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]890
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]891<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]892<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]893 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]894 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]895 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]896 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]897
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]898 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]899 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]900</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]901
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]902</body>
903</html>