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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 84c6e60c02645524a1f3b4c2351d6c12c21cac51 / . / docs / ReleaseNotes.html
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Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]6 <link rel="stylesheet" href="llvm.css" type="text/css">
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]7 <title>LLVM 2.7 Release Notes</title>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]8</head>
9<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]10
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]11<div class="doc_title">LLVM 2.7 Release Notes</div>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]12
Chris Lattner0e464a92010-03-17 04:02:39 +0000[diff] [blame]13<img align=right src="http://llvm.org/img/DragonSmall.png"
Gabor Greifee2187a2010-04-22 10:21:43 +0000[diff] [blame]14 width="136" height="136" alt="LLVM Dragon Logo">
Chris Lattner0e464a92010-03-17 04:02:39 +0000[diff] [blame]15
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]16<ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#intro">Introduction</a></li>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]18 <li><a href="#subproj">Sub-project Status Update</a></li>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]19 <li><a href="#externalproj">External Projects Using LLVM 2.7</a></li>
20 <li><a href="#whatsnew">What's New in LLVM 2.7?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +0000[diff] [blame]21 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]22 <li><a href="#portability">Portability and Supported Platforms</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 Lattner00736fc2010-04-13 06:37:00 +0000[diff] [blame]31<!--
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]32<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.8
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]33release.<br>
34You may prefer the
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]35<a href="http://llvm.org/releases/2.6/docs/ReleaseNotes.html">LLVM 2.7
Chris Lattner00736fc2010-04-13 06:37:00 +0000[diff] [blame]36Release Notes</a>.</h1>-->
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]37
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]38<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]39<div class="doc_section">
40 <a name="intro">Introduction</a>
41</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]42<!-- *********************************************************************** -->
43
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]44<div class="doc_text">
45
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]46<p>This document contains the release notes for the LLVM Compiler
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]47Infrastructure, release 2.7. Here we describe the status of LLVM, including
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]48major improvements from the previous release and significant known problems.
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]49All LLVM releases may be downloaded from the <a
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]50href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]51
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]52<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]53release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]54web site</a>. If you have questions or comments, the <a
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000[diff] [blame]55href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's
56Mailing List</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]57
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]58<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]59main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greiffa933f82008-10-14 11:00:32 +0000[diff] [blame]60current one. To see the release notes for a specific release, please see the
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]61<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]62
63</div>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]64
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]65
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]66<!--
67Almost dead code.
68 include/llvm/Analysis/LiveValues.h => Dan
69 lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8.
70 llvm/Analysis/PointerTracking.h => Edwin wants this, consider for 2.8.
Chris Lattner00736fc2010-04-13 06:37:00 +0000[diff] [blame]71 ABCD, GEPSplitterPass
Chris Lattner048fe3c2010-01-16 21:25:13 +0000[diff] [blame]72 MSIL backend?
Chris Lattnerdc910082010-03-17 06:41:58 +0000[diff] [blame]73 lib/Transforms/Utils/SSI.cpp -> ABCD depends on it.
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]74-->
75
76
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]77<!-- Features that need text if they're finished for 2.7:
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]78 combiner-aa?
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]79 strong phi elim
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]80 llvm.dbg.value: variable debug info for optimized code
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]81 loop dependence analysis
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]82 -->
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]83
Chris Lattner547a3912008-10-12 19:47:48 +0000[diff] [blame]84 <!-- for announcement email:
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]85 Logo web page.
86 llvm devmtg
87 compiler_rt
88 KLEE web page at klee.llvm.org
89 Many new papers added to /pubs/
Chris Lattnerdc910082010-03-17 06:41:58 +0000[diff] [blame]90 Mention gcc plugin.
Chris Lattner74c80df2009-02-25 06:34:50 +0000[diff] [blame]91 -->
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]92
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]93<!-- *********************************************************************** -->
94<div class="doc_section">
95 <a name="subproj">Sub-project Status Update</a>
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]96</div>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]97<!-- *********************************************************************** -->
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]98
99<div class="doc_text">
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]100<p>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]101The LLVM 2.7 distribution currently consists of code from the core LLVM
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]102repository (which roughly includes the LLVM optimizers, code generators
103and supporting tools), the Clang repository and the llvm-gcc repository. In
104addition to this code, the LLVM Project includes other sub-projects that are in
105development. Here we include updates on these subprojects.
Bill Wendling63d8c552009-03-02 04:28:57 +0000[diff] [blame]106</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]107
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]108</div>
109
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]110
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]111<!--=========================================================================-->
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]112<div class="doc_subsection">
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000[diff] [blame]113<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]114</div>
115
116<div class="doc_text">
117
Douglas Gregorf720a4e2010-04-22 20:42:40 +0000[diff] [blame]118<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C, C++, and Objective-C languages. Clang aims to provide a better user experience through expressive diagnostics, a high level of conformance to language standards, fast compilation, and low memory use. Like LLVM, Clang provides a modular, library-based architecture that makes it suitable for creating or integrating with other development tools. Clang is considered a production-quality compiler for C and Objective-C on x86 (32- and 64-bit).</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]119
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]120<p>In the LLVM 2.7 time-frame, the Clang team has made many improvements:</p>
Bill Wendling741748a2008-10-27 09:27:33 +0000[diff] [blame]121
Daniel Dunbar13739432008-10-14 23:25:09 +0000[diff] [blame]122<ul>
Douglas Gregorf720a4e2010-04-22 20:42:40 +0000[diff] [blame]123
124<li>C++ Support: Clang is now capable of self-hosting! While still alpha-quality, Clang's C++ support has matured enough to build LLVM and Clang, and C++ is now enabled by default. See the <a href="http://clang.llvm.org/cxx_compatibility.html">Clang C++ compatibility page</a> for common C++ migration issues.</li>
125
126<li>New warnings: Clang contains a number of new warnings, including control-flow warnings (unreachable code, missing return statements in a non-<code>void</code> function, etc.), sign-comparison warnings, and improved format-string warnings.</li>
Daniel Dunbar60dadb62010-03-25 16:09:18 +0000[diff] [blame]127
Daniel Dunbar60dadb62010-03-25 16:09:18 +0000[diff] [blame]128<li>CIndex API and Python bindings: Clang now includes a C API as part of the
129CIndex library. Although we make make some changes to the API in the future, it
130is intended to be stable and has been designed for use by external projects. See
131the Clang
132doxygen <a href="http://clang.llvm.org/doxygen/group__CINDEX.html">CIndex</a>
Wesley Peck1f433612010-04-22 14:19:00 +0000[diff] [blame]133documentation for more details. The CIndex API also includes a preliminary
Daniel Dunbar60dadb62010-03-25 16:09:18 +0000[diff] [blame]134set of Python bindings.</li>
135
136<li>ARM Support: Clang now has ABI support for both the Darwin and Linux ARM
137ABIs. Coupled with many improvements to the LLVM ARM backend, Clang is now
138suitable for use as a a beta quality ARM compiler.</li>
Bill Wendling6bc15282009-03-02 04:28:18 +0000[diff] [blame]139</ul>
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000[diff] [blame]140</div>
141
142<!--=========================================================================-->
143<div class="doc_subsection">
144<a name="clangsa">Clang Static Analyzer</a>
145</div>
146
147<div class="doc_text">
148
Chris Lattner8cdd7932010-04-22 06:38:11 +0000[diff] [blame]149<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a>
150 project is an effort to use static source code analysis techniques to
151 automatically find bugs in C and Objective-C programs (and hopefully <a
152 href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the
153 future</a>!). The tool is very good at finding bugs that occur on specific
154 paths through code, such as on error conditions.</p>
Chris Lattnercc042612008-10-14 00:52:49 +0000[diff] [blame]155
Chris Lattner8cdd7932010-04-22 06:38:11 +0000[diff] [blame]156<p>In the LLVM 2.7 time-frame, the analyzer core has made several major and
157 minor improvements, including better support for tracking the fields of
158 structures, initial support (not enabled by default yet) for doing
159 interprocedural (cross-function) analysis, and new checks have been added.
160</p>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]161
162</div>
163
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]164<!--=========================================================================-->
165<div class="doc_subsection">
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000[diff] [blame]166<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]167</div>
168
169<div class="doc_text">
170<p>
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000[diff] [blame]171The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]172a JVM and a CLI Virtual Machine (Microsoft .NET is an
173implementation of the CLI) using LLVM for static and just-in-time
174compilation.</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]175
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]176<p>
Chris Lattnerbf8e5162010-03-29 18:34:13 +0000[diff] [blame]177With the release of LLVM 2.7, VMKit has shifted to a great framework for writing
178virtual machines. VMKit now offers precise and efficient garbage collection with
179multi-threading support, thanks to the MMTk memory management toolkit, as well
180as just in time and ahead of time compilation with LLVM. The major changes in
181VMKit 0.27 are:</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]182
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000[diff] [blame]183<ul>
184
Chris Lattnerbf8e5162010-03-29 18:34:13 +0000[diff] [blame]185<li>Garbage collection: VMKit now uses the MMTk toolkit for garbage collectors.
186 The first collector to be ported is the MarkSweep collector, which is precise,
187 and drastically improves the performance of VMKit.</li>
188<li>Line number information in the JVM: by using the debug metadata of LLVM, the
189 JVM now supports precise line number information, useful when printing a stack
190 trace.</li>
191<li>Interface calls in the JVM: we implemented a variant of the Interface Method
192 Table technique for interface calls in the JVM.
193</li>
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000[diff] [blame]194
195</ul>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]196</div>
197
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]198
199<!--=========================================================================-->
200<div class="doc_subsection">
201<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
202</div>
203
204<div class="doc_text">
205<p>
206The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
207is a simple library that provides an implementation of the low-level
208target-specific hooks required by code generation and other runtime components.
209For example, when compiling for a 32-bit target, converting a double to a 64-bit
210unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
211function. The compiler-rt library provides highly optimized implementations of
212this and other low-level routines (some are 3x faster than the equivalent
213libgcc routines).</p>
214
215<p>
216All of the code in the compiler-rt project is available under the standard LLVM
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]217License, a "BSD-style" license. New in LLVM 2.7: compiler_rt now
218supports ARM targets.</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]219
220</div>
221
222<!--=========================================================================-->
223<div class="doc_subsection">
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]224<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]225</div>
226
227<div class="doc_text">
228<p>
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]229<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
230gcc-4.5. Unlike llvm-gcc, which makes many intrusive changes to the underlying
231gcc-4.2 code, dragonegg in theory does not require any gcc-4.5 modifications
232whatsoever (currently one small patch is needed). This is thanks to the new
233<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>, which
234makes it possible to modify the behaviour of gcc at runtime by loading a plugin,
235which is nothing more than a dynamic library which conforms to the gcc plugin
236interface. DragonEgg is a gcc plugin that causes the LLVM optimizers to be run
237instead of the gcc optimizers, and the LLVM code generators instead of the gcc
238code generators, just like llvm-gcc. To use it, you add
239"-fplugin=path/dragonegg.so" to the gcc-4.5 command line, and gcc-4.5 magically
240becomes llvm-gcc-4.5!
241</p>
242
243<p>
244DragonEgg is still a work in progress. Currently C works very well, while C++,
245Ada and Fortran work fairly well. All other languages either don't work at all,
246or only work poorly. For the moment only the x86-32 and x86-64 targets are
Duncan Sands51a51742010-04-20 19:40:58 +0000[diff] [blame]247supported, and only on linux and darwin (darwin needs an additional gcc patch).
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]248</p>
249
250<p>
Duncan Sandscb9dda62010-04-21 13:51:48 +0000[diff] [blame]251DragonEgg is a new project which is seeing its first release with llvm-2.7.
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]252</p>
253
254</div>
255
256
257<!--=========================================================================-->
258<div class="doc_subsection">
259<a name="mc">llvm-mc: Machine Code Toolkit</a>
260</div>
261
262<div class="doc_text">
263<p>
Chris Lattner8cdd7932010-04-22 06:38:11 +0000[diff] [blame]264The LLVM Machine Code (aka MC) sub-project of LLVM was created to solve a number
265of problems in the realm of assembly, disassembly, object file format handling,
266and a number of other related areas that CPU instruction-set level tools work
267in. It is a sub-project of LLVM which provides it with a number of advantages
268over other compilers that do not have tightly integrated assembly-level tools.
269For a gentle introduction, please see the <a
270href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
271LLVM MC Project Blog Post</a>.
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]272</p>
273
Chris Lattner8cdd7932010-04-22 06:38:11 +0000[diff] [blame]274<p>2.7 includes major parts of the work required by the new MC Project. A few
275 targets have been refactored to support it, and work is underway to support a
276 native assembler in LLVM. This work is not complete in LLVM 2.7, but you has
277 made substantially more progress on LLVM mainline.</p>
278
279<p>One minor example of what MC can do is to transcode an AT&amp;T syntax
Gabor Greifed387452010-04-22 10:25:23 +0000[diff] [blame]280 X86 .s file into intel syntax. You can do this with something like:</p>
Chris Lattner8cdd7932010-04-22 06:38:11 +0000[diff] [blame]281<pre>
282 llvm-mc foo.s -output-asm-variant=1 -o foo-intel.s
283</pre>
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]284
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]285</div>
286
287
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]288<!-- *********************************************************************** -->
289<div class="doc_section">
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]290 <a name="externalproj">External Open Source Projects Using LLVM 2.7</a>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]291</div>
292<!-- *********************************************************************** -->
293
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]294<div class="doc_text">
295
296<p>An exciting aspect of LLVM is that it is used as an enabling technology for
297 a lot of other language and tools projects. This section lists some of the
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]298 projects that have already been updated to work with LLVM 2.7.</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]299</div>
300
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]301<!--=========================================================================-->
302<div class="doc_subsection">
303<a name="pure">Pure</a>
304</div>
305
306<div class="doc_text">
307<p>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]308<a href="http://pure-lang.googlecode.com/">Pure</a>
309is an algebraic/functional programming language based on term rewriting.
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]310Programs are collections of equations which are used to evaluate expressions in
311a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]312lexical closures, a hygienic macro system (also based on term rewriting),
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]313built-in list and matrix support (including list and matrix comprehensions) and
314an easy-to-use C interface. The interpreter uses LLVM as a backend to
315 JIT-compile Pure programs to fast native code.</p>
316
Chris Lattner477a1fd2010-03-17 17:25:49 +0000[diff] [blame]317<p>Pure versions 0.43 and later have been tested and are known to work with
318LLVM 2.7 (and continue to work with older LLVM releases >= 2.5).</p>
319
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]320</div>
321
Chris Lattnerbc31caf2009-02-28 18:58:01 +0000[diff] [blame]322<!--=========================================================================-->
323<div class="doc_subsection">
324<a name="RoadsendPHP">Roadsend PHP</a>
325</div>
326
327<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]328<p>
329<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
Chris Lattnercade8222009-03-02 19:07:24 +0000[diff] [blame]330source implementation of the PHP programming
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]331language that uses LLVM for its optimizer, JIT and static compiler. This is a
Chris Lattner0e464a92010-03-17 04:02:39 +0000[diff] [blame]332reimplementation of an earlier project that is now based on LLVM.
Chris Lattner477a1fd2010-03-17 17:25:49 +0000[diff] [blame]333</p>
Chris Lattnerbc31caf2009-02-28 18:58:01 +0000[diff] [blame]334</div>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]335
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]336<!--=========================================================================-->
337<div class="doc_subsection">
338<a name="UnladenSwallow">Unladen Swallow</a>
339</div>
340
341<div class="doc_text">
342<p>
343<a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
344branch of <a href="http://python.org/">Python</a> intended to be fully
345compatible and significantly faster. It uses LLVM's optimization passes and JIT
Chris Lattnerb5f6feb2010-03-18 06:52:15 +0000[diff] [blame]346compiler.
Chris Lattner0e464a92010-03-17 04:02:39 +0000[diff] [blame]347</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]348</div>
349
350<!--=========================================================================-->
351<div class="doc_subsection">
Chris Lattner8d4bbbe2010-03-29 17:50:39 +0000[diff] [blame]352<a name="tce">TTA-based Codesign Environment (TCE)</a>
353</div>
354
355<div class="doc_text">
356<p>
357<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing
358application-specific processors (ASP) based on the Transport triggered
359architecture (TTA). The toolset provides a complete co-design flow from C/C++
360programs down to synthesizable VHDL and parallel program binaries. Processor
361customization points include the register files, function units, supported
362operations, and the interconnection network.</p>
363
364<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target
365independent optimizations and also for parts of code generation. It generates
366new LLVM-based code generators "on the fly" for the designed TTA processors and
367loads them in to the compiler backend as runtime libraries to avoid per-target
368recompilation of larger parts of the compiler chain.</p>
369
370</div>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]371
John Criswellf77cdab2010-04-06 14:52:14 +0000[diff] [blame]372<!--=========================================================================-->
373<div class="doc_subsection">
374<a name="safecode">SAFECode Compiler</a>
375</div>
376
377<div class="doc_text">
378<p>
379<a href="http://safecode.cs.illinois.edu">SAFECode</a> is a memory safe C
380compiler built using LLVM. It takes standard, unannotated C code, analyzes the
381code to ensure that memory accesses and array indexing operations are safe, and
382instruments the code with run-time checks when safety cannot be proven
383statically.
384</p>
385</div>
386
Chris Lattnerfb1a7392010-04-22 17:28:36 +0000[diff] [blame]387<!--=========================================================================-->
388<div class="doc_subsection">
389<a name="icedtea">IcedTea Java Virtual Machine Implementation</a>
390</div>
John Criswellf77cdab2010-04-06 14:52:14 +0000[diff] [blame]391
Chris Lattnerfb1a7392010-04-22 17:28:36 +0000[diff] [blame]392<div class="doc_text">
393<p>
394<a href="http://icedtea.classpath.org/wiki/Main_Page">IcedTea</a> provides a
395harness to build OpenJDK using only free software build tools and to provide
396replacements for the not-yet free parts of OpenJDK. One of the extensions that
397IcedTea provides is a new JIT compiler named <a
398href="http://icedtea.classpath.org/wiki/ZeroSharkFaq">Shark</a> which uses LLVM
399to provide native code generation without introducing processor-dependent
400code.
401</p>
402<p>Icedtea6 1.8 and later have been tested and are known to work with
403LLVM 2.7 (and continue to work with older LLVM releases >= 2.6 as well).
404</p>
405</div>
406
407<!--=========================================================================-->
408<div class="doc_subsection">
409<a name="llvm-lua">LLVM-Lua</a>
410</div>
411
412<div class="doc_text">
413<p>
414<a href="http://code.google.com/p/llvm-lua/">LLVM-Lua</a> uses LLVM
415 to add JIT and static compiling support to the Lua VM. Lua
416bytecode is analyzed to remove type checks, then LLVM is used to compile the
417bytecode down to machine code.
418</p>
419<p>LLVM-Lua 1.2.0 have been tested and is known to work with LLVM 2.7.
420</p>
421</div>
Chris Lattner3a1d4cf2010-04-22 21:34:16 +0000[diff] [blame]422
423<!--=========================================================================-->
424<div class="doc_subsection">
425<a name="MacRuby">MacRuby</a>
426</div>
427
428<div class="doc_text">
429<p>
430<a href="http://macruby.org">MacRuby</a> is an implementation of Ruby based on
431core Mac OS technologies, sponsored by Apple Inc. It uses LLVM at runtime for
432optimization passes, JIT compilation and exception handling. It also allows
433static (ahead-of-time) compilation of Ruby code straight to machine code.
434</p>
435<p>The upcoming MacRuby 0.6 release works with LLVM 2.7.
436</p>
437</div>
438
439
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]440<!-- *********************************************************************** -->
441<div class="doc_section">
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]442 <a name="whatsnew">What's New in LLVM 2.7?</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]443</div>
444<!-- *********************************************************************** -->
445
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]446<div class="doc_text">
447
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]448<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]449minor improvements. Some of the major improvements and new features are listed
450in this section.
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]451</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]452
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]453</div>
454
455<!--=========================================================================-->
456<div class="doc_subsection">
457<a name="orgchanges">LLVM Community Changes</a>
458</div>
459
460<div class="doc_text">
461
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]462<p>In addition to changes to the code, between LLVM 2.6 and 2.7, a number of
463organization changes have happened:
464</p>
465
466<ul>
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]467<li>LLVM has a new <a href="http://llvm.org/Logo.html">official logo</a>!</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]468
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]469<li>Ted Kremenek and Doug Gregor have stepped forward as <a
470 href="http://llvm.org/docs/DeveloperPolicy.html#owners">Code Owners</a> of the
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]471 Clang static analyzer and the Clang frontend, respectively.</li>
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]472
473<li>LLVM now has an <a href="http://blog.llvm.org">official Blog</a> at
474 <a href="http://blog.llvm.org">http://blog.llvm.org</a>. This is a great way
475 to learn about new LLVM-related features as they are implemented. Several
476 features in this release are already explained on the blog.</li>
477
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]478<li>The LLVM web pages are now checked into the SVN server, in the "www",
479 "www-pubs" and "www-releases" SVN modules. Previously they were hidden in a
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]480 largely inaccessible old CVS server.</li>
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]481
482<li><a href="http://llvm.org">llvm.org</a> is now hosted on a new (and much
483 faster) server. It is still graciously hosted at the University of Illinois
484 of Urbana Champaign.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]485</ul>
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]486</div>
487
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]488<!--=========================================================================-->
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]489<div class="doc_subsection">
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]490<a name="majorfeatures">Major New Features</a>
491</div>
492
493<div class="doc_text">
494
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]495<p>LLVM 2.7 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]496
497<ul>
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]498<li>2.7 includes initial support for the <a
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]499 href="http://en.wikipedia.org/wiki/MicroBlaze">MicroBlaze</a> target.
500 MicroBlaze is a soft processor core designed for Xilinx FPGAs.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]501
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]502<li>2.7 includes a new LLVM IR "extensible metadata" feature. This feature
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]503 supports many different use cases, including allowing front-end authors to
504 encode source level information into LLVM IR, which is consumed by later
505 language-specific passes. This is a great way to do high-level optimizations
506 like devirtualization, type-based alias analysis, etc. See the <a
507 href="http://blog.llvm.org/2010/04/extensible-metadata-in-llvm-ir.html">
508 Extensible Metadata Blog Post</a> for more information.</li>
509
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]510<li>2.7 encodes <a href="SourceLevelDebugging.html">debug information</a>
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]511in a completely new way, built on extensible metadata. The new implementation
512is much more memory efficient and paves the way for improvements to optimized
513code debugging experience.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]514
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]515<li>2.7 now directly supports taking the address of a label and doing an
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]516 indirect branch through a pointer. This is particularly useful for
517 interpreter loops, and is used to implement the GCC "address of label"
518 extension. For more information, see the <a
519href="http://blog.llvm.org/2010/01/address-of-label-and-indirect-branches.html">
520Address of Label and Indirect Branches in LLVM IR Blog Post</a>.
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]521
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]522<li>2.7 is the first release to start supporting APIs for assembling and
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]523 disassembling target machine code. These APIs are useful for a variety of
524 low level clients, and are surfaced in the new "enhanced disassembly" API.
525 For more information see the <a
526 href="http://blog.llvm.org/2010/01/x86-disassembler.html">The X86
527 Disassembler Blog Post</a> for more information.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]528
Chris Lattner8cdd7932010-04-22 06:38:11 +0000[diff] [blame]529<li>2.7 includes major parts of the work required by the new MC Project,
530 see the <a href="#mc">MC update above</a> for more information.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]531
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]532</ul>
Chris Lattnerdc910082010-03-17 06:41:58 +0000[diff] [blame]533
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]534</div>
535
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]536<!--=========================================================================-->
537<div class="doc_subsection">
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]538<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]539</div>
540
541<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]542<p>LLVM IR has several new features for better support of new targets and that
543expose new optimization opportunities:</p>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]544
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]545<ul>
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]546<li>LLVM IR now supports a 16-bit "half float" data type through <a
547 href="LangRef.html#int_fp16">two new intrinsics</a> and APFloat support.</li>
548<li>LLVM IR supports two new <a href="LangRef.html#fnattrs">function
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]549 attributes</a>: inlinehint and alignstack(n). The former is a hint to the
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]550 optimizer that a function was declared 'inline' and thus the inliner should
551 weight it higher when considering inlining it. The later
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]552 indicates to the code generator that the function diverges from the platform
553 ABI on stack alignment.</li>
554<li>The new <a href="LangRef.html#int_objectsize">llvm.objectsize</a> intrinsic
555 allows the optimizer to infer the sizes of memory objects in some cases.
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]556 This intrinsic is used to implement the GCC <tt>__builtin_object_size</tt>
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]557 extension.</li>
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]558<li>LLVM IR now supports marking load and store instructions with <a
559 href="LangRef.html#i_load">"non-temporal" hints</a> (building on the new
560 metadata feature). This hint encourages the code
561 generator to generate non-temporal accesses when possible, which are useful
562 for code that is carefully managing cache behavior. Currently, only the
563 X86 backend provides target support for this feature.</li>
564
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]565<li>LLVM 2.7 has pre-alpha support for <a
Gabor Greifc8b3af92010-04-22 10:11:24 +0000[diff] [blame]566 href="LangRef.html#t_union">unions in LLVM IR</a>.
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]567 Unfortunately, this support is not really usable in 2.7, so if you're
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]568 interested in pushing it forward, please help contribute to LLVM mainline.</li>
Gabor Greifee2187a2010-04-22 10:21:43 +0000[diff] [blame]569
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]570</ul>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]571
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]572</div>
573
574<!--=========================================================================-->
575<div class="doc_subsection">
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]576<a name="optimizer">Optimizer Improvements</a>
577</div>
578
579<div class="doc_text">
580
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]581<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]582release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]583
584<ul>
585
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]586<li>The inliner reuses now merges arrays stack objects in different callees when
587 inlining multiple call sites into one function. This reduces the stack size
588 of the resultant function.</li>
589<li>The -basicaa alias analysis pass (which is the default) has been improved to
590 be less dependent on "type safe" pointers. It can now look through bitcasts
591 and other constructs more aggressively, allowing better load/store
592 optimization.</li>
593<li>The load elimination optimization in the GVN Pass [<a
594href="http://blog.llvm.org/2009/12/introduction-to-load-elimination-in-gvn.html">intro
595 blog post</a>] has been substantially improved to be more aggressive about
596 partial redundancy elimination and do more aggressive phi translation. Please
597 see the <a
598 href="http://blog.llvm.org/2009/12/advanced-topics-in-redundant-load.html">
599 Advanced Topics in Redundant Load Elimination with a Focus on PHI Translation
600 Blog Post</a> for more details.</li>
601<li>The module <a href="LangRef.html#datalayout">target data string</a> now
Wesley Peck68d1fe92010-04-22 13:28:34 +0000[diff] [blame]602 includes a notion of 'native' integer data types for the target. This
603 helps mid-level optimizations avoid promoting complex sequences of
604 operations to data types that are not natively supported (e.g. converting
605 i32 operations to i64 on 32-bit chips).</li>
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]606<li>The mid-level optimizer is now conservative when operating on a module with
607 no target data. Previously, it would default to SparcV9 settings, which is
608 not what most people expected.</li>
Chris Lattnera54c1f72010-04-21 06:42:24 +0000[diff] [blame]609<li>Jump threading is now much more aggressive at simplifying correlated
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]610 conditionals and threading blocks with otherwise complex logic. It has
611 subsumed the old "Conditional Propagation" pass, and -condprop has been
612 removed from LLVM 2.7.</li>
613<li>The -instcombine pass has been refactored from being one huge file to being
614 a library of its own. Internally, it uses a customized IRBuilder to clean
615 it up and simplify it.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]616
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]617<li>The optimal edge profiling pass is reliable and much more complete than in
618 2.6. It can be used with the llvm-prof tool but isn't wired up to the
619 llvm-gcc and clang command line options yet.</li>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]620
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]621<li>A new experimental alias analysis implementation, -scev-aa, has been added.
622 It uses LLVM's Scalar Evolution implementation to do symbolic analysis of
623 pointer offset expressions to disambiguate pointers. It can catch a few
624 cases that basicaa cannot, particularly in complex loop nests.</li>
Chris Lattnera54c1f72010-04-21 06:42:24 +0000[diff] [blame]625
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]626<li>The default pass ordering has been tweaked for improved optimization
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]627 effectiveness.</li>
Chris Lattnera54c1f72010-04-21 06:42:24 +0000[diff] [blame]628
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]629</ul>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]630
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]631</div>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]632
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]633
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]634<!--=========================================================================-->
635<div class="doc_subsection">
636<a name="executionengine">Interpreter and JIT Improvements</a>
637</div>
Chris Lattnerf3013872008-10-13 21:50:36 +0000[diff] [blame]638
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]639<div class="doc_text">
640
641<ul>
Wesley Peck640604a2010-04-22 13:36:27 +0000[diff] [blame]642<li>The JIT now supports generating debug information and is compatible with
643the new GDB 7.0 (and later) interfaces for registering dynamically generated
644debug info.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]645
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]646<li>The JIT now <a href="http://llvm.org/PR5184">defaults
Jeffrey Yasskin01eba392010-01-29 19:10:38 +0000[diff] [blame]647to compiling eagerly</a> to avoid a race condition in the lazy JIT.
648Clients that still want the lazy JIT can switch it on by calling
649<tt>ExecutionEngine::DisableLazyCompilation(false)</tt>.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]650
Jeffrey Yasskin40966a72010-02-11 01:07:39 +0000[diff] [blame]651<li>It is now possible to create more than one JIT instance in the same process.
652These JITs can generate machine code in parallel,
653although <a href="http://llvm.org/docs/ProgrammersManual.html#jitthreading">you
654still have to obey the other threading restrictions</a>.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]655
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]656</ul>
657
658</div>
659
660<!--=========================================================================-->
661<div class="doc_subsection">
Chris Lattner511433e2009-03-02 03:24:11 +0000[diff] [blame]662<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]663</div>
664
665<div class="doc_text">
666
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]667<p>We have put a significant amount of work into the code generator
668infrastructure, which allows us to implement more aggressive algorithms and make
669it run faster:</p>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]670
671<ul>
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]672<li>The 'llc -asm-verbose' option (which is now the default) has been enhanced
673 to emit many useful comments to .s files indicating information about spill
674 slots and loop nest structure. This should make it much easier to read and
675 understand assembly files. This is wired up in llvm-gcc and clang to
676 the <tt>-fverbose-asm</tt> option.</li>
677
Dan Gohman9c675f12010-04-22 20:50:43 +0000[diff] [blame]678<li>New LSR with "full strength reduction" mode, which can reduce address
679 register pressure in loops where address generation is important.</li>
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]680
681<li>A new codegen level Common Subexpression Elimination pass (MachineCSE)
682 is available and enabled by default. It catches redundancies exposed by
683 lowering.</li>
684<li>A new pre-register-allocation tail duplication pass is available and enabled
685 by default, it can substantially improve branch prediction quality in some
686 cases.</li>
687<li>A new sign and zero extension optimization pass (OptimizeExtsPass)
688 is available and enabled by default. This pass can takes advantage
689 architecture features like x86-64 implicit zero extension behavior and
690 sub-registers.</li>
691<li>The code generator now supports a mode where it attempts to preserve the
692 order of instructions in the input code. This is important for source that
693 is hand scheduled and extremely sensitive to scheduling. It is compatible
694 with the GCC <tt>-fno-schedule-insns</tt> option.</li>
695<li>The target-independent code generator now supports generating code with
696 arbitrary numbers of result values. Returning more values than was
697 previously supported is handled by returning through a hidden pointer. In
698 2.7, only the X86 and XCore targets have adopted support for this
699 though.</li>
700<li>The code generator now supports generating code that follows the
701 <a href="LangRef.html#callingconv">Glasgow Haskell Compiler Calling
702 Convention</a> and ABI.</li>
703<li>The "<a href="CodeGenerator.html#selectiondag_select">DAG instruction
704 selection</a>" phase of the code generator has been largely rewritten for
705 2.7. Previously, tblgen spit out tons of C++ code which was compiled and
706 linked into the target to do the pattern matching, now it emits a much
707 smaller table which is read by the target-independent code. The primary
708 advantages of this approach is that the size and compile time of various
709 targets is much improved. The X86 code generator shrunk by 1.5MB of code,
710 for example.</li>
711<li>Almost the entire code generator has switched to emitting code through the
712 MC interfaces instead of printing textually to the .s file. This led to a
713 number of cleanups and speedups. In 2.7, debug an exception handling
714 information does not go through MC yet.</li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]715</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]716</div>
717
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]718<!--=========================================================================-->
719<div class="doc_subsection">
720<a name="x86">X86-32 and X86-64 Target Improvements</a>
721</div>
722
723<div class="doc_text">
724<p>New features of the X86 target include:
725</p>
726
727<ul>
Chris Lattnera54c1f72010-04-21 06:42:24 +0000[diff] [blame]728<li>The X86 backend now optimizes tails calls much more aggressively for
729 functions that use the standard C calling convention.</li>
730<li>The X86 backend now models scalar SSE registers as subregs of the SSE vector
731 registers, making the code generator more aggressive in cases where scalars
732 and vector types are mixed.</li>
Chris Lattner511433e2009-03-02 03:24:11 +0000[diff] [blame]733
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]734</ul>
735
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]736</div>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]737
738<!--=========================================================================-->
739<div class="doc_subsection">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]740<a name="ARM">ARM Target Improvements</a>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]741</div>
742
743<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]744<p>New features of the ARM target include:
745</p>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]746
747<ul>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]748
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]749<li>The ARM backend now generates instructions in unified assembly syntax.</li>
750
751<li>llvm-gcc now has complete support for the ARM v7 NEON instruction set. This
752 support differs slightly from the GCC implementation. Please see the
753 <a
754href="http://blog.llvm.org/2010/04/arm-advanced-simd-neon-intrinsics-and.html">
755 ARM Advanced SIMD (NEON) Intrinsics and Types in LLVM Blog Post</a> for
756 helpful information if migrating code from GCC to LLVM-GCC.</li>
757
Wesley Peck9e385b12010-04-22 13:43:14 +0000[diff] [blame]758<li>The ARM and Thumb code generators now use register scavenging for stack
Jim Grosbach269e0fe2010-04-22 18:28:43 +0000[diff] [blame]759 object address materialization. This allows the use of R3 as a general
760 purpose register in Thumb1 code, as it was previous reserved for use in
761 stack address materialization. Secondly, sequential uses of the same
762 value will now re-use the materialized constant.</li>
763
Wesley Peck9e385b12010-04-22 13:43:14 +0000[diff] [blame]764<li>The ARM backend now has good support for ARMv4 targets and has been tested
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]765 on StrongARM hardware. Previously, LLVM only supported ARMv4T and
766 newer chips.</li>
Jim Grosbach41a77662010-04-22 18:33:31 +0000[diff] [blame]767
768<li>Atomic builtins are now supported for ARMv6 and ARMv7 (__sync_synchronize,
769 __sync_fetch_and_add, etc.).</li>
770
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]771</ul>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]772
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]773
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]774</div>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]775
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]776<!--=========================================================================-->
777<div class="doc_subsection">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]778<a name="newapis">New Useful APIs</a>
779</div>
780
781<div class="doc_text">
782
783<p>This release includes a number of new APIs that are used internally, which
784 may also be useful for external clients.
785</p>
786
787<ul>
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]788<li>The optimizer uses the new CodeMetrics class to measure the size of code.
Chris Lattner83cd35a2010-04-22 17:39:38 +0000[diff] [blame]789 Various passes (like the inliner, loop unswitcher, etc) all use this to make
790 more accurate estimates of the code size impact of various
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]791 optimizations.</li>
792<li>A new <a href="http://llvm.org/doxygen/InstructionSimplify_8h-source.html">
Wesley Peckc0287ba2010-04-22 13:50:46 +0000[diff] [blame]793 llvm/Analysis/InstructionSimplify.h</a> interface is available for doing
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]794 symbolic simplification of instructions (e.g. <tt>a+0</tt> -&gt; <tt>a</tt>)
795 without requiring the instruction to exist. This centralizes a lot of
796 ad-hoc symbolic manipulation code scattered in various passes.</li>
797<li>The optimizer now uses a new <a
798 href="http://llvm.org/doxygen/SSAUpdater_8h-source.html">SSAUpdater</a>
799 class which efficiently supports
800 doing unstructured SSA update operations. This centralized a bunch of code
Wesley Peckc0287ba2010-04-22 13:50:46 +0000[diff] [blame]801 scattered throughout various passes (e.g. jump threading, lcssa,
802 loop rotate, etc) for doing this sort of thing. The code generator has a
803 similar <a href="http://llvm.org/doxygen/MachineSSAUpdater_8h-source.html">
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]804 MachineSSAUpdater</a> class.</li>
805<li>The <a href="http://llvm.org/doxygen/Regex_8h-source.html">
806 llvm/Support/Regex.h</a> header exposes a platform independent regular
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]807 expression API. Building on this, the <a
808 href="TestingGuide.html#FileCheck">FileCheck</a> utility now supports
809 regular exressions.</li>
810<li>raw_ostream now supports a circular "debug stream" accessed with "dbgs()".
811 By default, this stream works the same way as "errs()", but if you pass
812 <tt>-debug-buffer-size=1000</tt> to opt, the debug stream is capped to a
813 fixed sized circular buffer and the output is printed at the end of the
814 program's execution. This is helpful if you have a long lived compiler
815 process and you're interested in seeing snapshots in time.</li>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]816</ul>
817
818
819</div>
820
821<!--=========================================================================-->
822<div class="doc_subsection">
823<a name="otherimprovements">Other Improvements and New Features</a>
824</div>
825
826<div class="doc_text">
827<p>Other miscellaneous features include:</p>
828
829<ul>
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]830<li>You can now build LLVM as a big dynamic library (e.g. "libllvm2.7.so"). To
831 get this, configure LLVM with the --enable-shared option.</li>
832
Wesley Pecka0c44842010-04-22 13:53:54 +0000[diff] [blame]833<li>LLVM command line tools now overwrite their output by default. Previously,
834 they would only do this with -f. This makes them more convenient to use, and
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]835 behave more like standard unix tools.</li>
836
837<li>The opt and llc tools now autodetect whether their input is a .ll or .bc
838 file, and automatically do the right thing. This means you don't need to
839 explicitly use the llvm-as tool for most things.</li>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]840</ul>
841
842</div>
843
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]844
845<!--=========================================================================-->
846<div class="doc_subsection">
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]847<a name="changes">Major Changes and Removed Features</a>
848</div>
849
850<div class="doc_text">
851
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]852<p>If you're already an LLVM user or developer with out-of-tree changes based
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]853on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]854from the previous release.</p>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]855
856<ul>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]857
858<li>
859The Andersen's alias analysis ("anders-aa") pass, the Predicate Simplifier
860("predsimplify") pass, the LoopVR pass, the GVNPRE pass, and the random sampling
861profiling ("rsprofiling") passes have all been removed. They were not being
862actively maintained and had substantial problems. If you are interested in
863these components, you are welcome to ressurect them from SVN, fix the
864correctness problems, and resubmit them to mainline.</li>
865
866<li>LLVM now defaults to building most libraries with RTTI turned off, providing
867a code size reduction. Packagers who are interested in building LLVM to support
868plugins that require RTTI information should build with "make REQUIRE_RTTI=1"
869and should read the new <a href="Packaging.html">Advice on Packaging LLVM</a>
870document.</li>
871
Jeffrey Yasskinbc83d062010-02-09 23:03:44 +0000[diff] [blame]872<li>The LLVM interpreter now defaults to <em>not</em> using <tt>libffi</tt> even
873if you have it installed. This makes it more likely that an LLVM built on one
874system will work when copied to a similar system. To use <tt>libffi</tt>,
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]875configure with <tt>--enable-libffi</tt>.</li>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]876
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]877<li>Debug information uses a completely different representation, an LLVM 2.6
878.bc file should work with LLVM 2.7, but debug info won't come forward.</li>
879
880<li>The LLVM 2.6 (and earlier) "malloc" and "free" instructions got removed,
881 along with LowerAllocations pass. Now you should just use a call to the
882 malloc and free functions in libc. These calls are optimized as well as
883 the old instructions were.</li>
884</ul>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]885
886<p>In addition, many APIs have changed in this release. Some of the major LLVM
887API changes are:</p>
888
889<ul>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]890<li>Just about everything has been converted to use raw_ostream instead of
891 std::ostream.</li>
892<li>llvm/ADT/iterator.h has been removed, just use &lt;iterator&gt;
893 instead.</li>
894<li>The Streams.h file and "DOUT" got removed, use "DEBUG(errs() &lt;&lt; ...);"
895 instead.</li>
Chris Lattnercd062cd2010-04-22 17:25:00 +0000[diff] [blame]896<li>The TargetAsmInfo interface was renamed to MCAsmInfo.</li>
Jeffrey Yasskin4fcd6072010-01-28 01:41:20 +0000[diff] [blame]897<li><tt>ModuleProvider</tt> has been <a
Gabor Greifee2187a2010-04-22 10:21:43 +0000[diff] [blame]898href="http://llvm.org/viewvc/llvm-project?view=rev&amp;revision=94686">removed</a>
Jeffrey Yasskin4fcd6072010-01-28 01:41:20 +0000[diff] [blame]899and its methods moved to <tt>Module</tt> and <tt>GlobalValue</tt>.
900Most clients can remove uses of <tt>ExistingModuleProvider</tt>,
901replace <tt>getBitcodeModuleProvider</tt> with
902<tt>getLazyBitcodeModule</tt>, and pass their <tt>Module</tt> to
903functions that used to accept <tt>ModuleProvider</tt>. Clients who
904wrote their own <tt>ModuleProvider</tt>s will need to derive from
905<tt>GVMaterializer</tt> instead and use
906<tt>Module::setMaterializer</tt> to attach it to a
907<tt>Module</tt>.</li>
908
909<li><tt>GhostLinkage</tt> has given up the ghost.
910<tt>GlobalValue</tt>s that have not yet been read from their backing
911storage have the same linkage they will have after being read in.
912Clients must replace calls to
913<tt>GlobalValue::hasNotBeenReadFromBitcode</tt> with
914<tt>GlobalValue::isMaterializable</tt>.</li>
Daniel Dunbar4acdede2010-02-10 04:09:52 +0000[diff] [blame]915
Duncan Sands411432d2010-02-17 17:20:17 +0000[diff] [blame]916<li>The <tt>isInteger</tt>, <tt>isIntOrIntVector</tt>, <tt>isFloatingPoint</tt>,
917<tt>isFPOrFPVector</tt> and <tt>isFPOrFPVector</tt> methods have been renamed
918<tt>isIntegerTy</tt>, <tt>isIntOrIntVectorTy</tt>, <tt>isFloatingPointTy</tt>,
919<tt>isFPOrFPVectorTy</tt> and <tt>isFPOrFPVectorTy</tt> respectively.</li>
Chris Lattnercd062cd2010-04-22 17:25:00 +0000[diff] [blame]920
921<li><tt>llvm::Instruction::clone()</tt> no longer takes argument.</li>
922<li><tt>raw_fd_ostream</tt>'s constructor now takes a flag argument, not individual
923 booleans (see <tt>include/llvm/Support/raw_ostream.h</tt> for details).</li>
924<li>Some header files have been renamed:
925<ul>
926 <li><tt>llvm/Support/AIXDataTypesFix.h</tt> to
927 <tt>llvm/System/AIXDataTypesFix.h</tt></li>
928 <li><tt>llvm/Support/DataTypes.h</tt> to <tt>llvm/System/DataTypes.h</tt></li>
929 <li><tt>llvm/Transforms/Utils/InlineCost.h</tt> to
930 <tt>llvm/Analysis/InlineCost.h</tt></li>
931 <li><tt>llvm/Support/Mangler.h</tt> to <tt>llvm/Target/Mangler.h</tt></li>
932 <li><tt>llvm/Analysis/Passes.h</tt> to <tt>llvm/CodeGen/Passes.h</tt></li>
933</ul></li>
Devang Patelb34dd132008-10-14 20:03:43 +0000[diff] [blame]934</ul>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]935
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]936</div>
937
938
939
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]940<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]941<div class="doc_section">
942 <a name="portability">Portability and Supported Platforms</a>
943</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]944<!-- *********************************************************************** -->
945
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]946<div class="doc_text">
947
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]948<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]949
950<ul>
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]951<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]952 Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like
953 systems).</li>
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]954<li>PowerPC and X86-based Mac OS X systems, running 10.4 and above in 32-bit
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]955 and 64-bit modes.</li>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]956<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]957<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
958 support is available for native builds with Visual C++).</li>
Chris Lattner7e23d6e2009-10-16 16:30:58 +0000[diff] [blame]959<li>Sun x86 and AMD64 machines running Solaris 10, OpenSolaris 0906.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]960<li>Alpha-based machines running Debian GNU/Linux.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]961</ul>
962
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]963<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]964to the machine and operating system on which it is built. However, minor
965porting may be required to get LLVM to work on new platforms. We welcome your
966portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]967
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]968</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]969
970<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]971<div class="doc_section">
972 <a name="knownproblems">Known Problems</a>
973</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]974<!-- *********************************************************************** -->
975
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]976<div class="doc_text">
977
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]978<p>This section contains significant known problems with the LLVM system,
Chris Lattnere18b32e2008-11-10 05:40:34 +0000[diff] [blame]979listed by component. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]980href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]981there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]982
Chris Lattner477a1fd2010-03-17 17:25:49 +0000[diff] [blame]983<ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]984<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
985using the stock GCC 3.x.x series 'out the box',
Chris Lattner554ee4a2009-11-03 21:50:09 +0000[diff] [blame]986See: <a href="GettingStarted.html#brokengcc">Broken versions of GCC and other tools</a>.
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]987However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
988for x86/x86-64 has been made available from the third party AuroraUX Project
989that has been meticulously tested for bootstrapping LLVM &amp; Clang.</li>
990</ul>
991
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]992</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]993
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]994<!-- ======================================================================= -->
995<div class="doc_subsection">
996 <a name="experimental">Experimental features included with this release</a>
997</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]998
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]999<div class="doc_text">
1000
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]1001<p>The following components of this LLVM release are either untested, known to
1002be broken or unreliable, or are in early development. These components should
1003not be relied on, and bugs should not be filed against them, but they may be
1004useful 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]1005components, please contact us on the <a
1006href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]1007
1008<ul>
Wesley Peck7c4a1212010-03-18 14:31:30 +0000[diff] [blame]1009<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
1010 backends are experimental.</li>
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]1011<li><tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000[diff] [blame]1012 supported value for this option. The MachO writer is experimental, and
1013 works much better in mainline SVN.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]1014</ul>
1015
1016</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1017
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1018<!-- ======================================================================= -->
1019<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1020 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]1021</div>
1022
1023<div class="doc_text">
1024
1025<ul>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]1026 <li>The X86 backend does not yet support
1027 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
1028 floating point stack</a>. It supports the 'f' and 't' constraints, but not
1029 'u'.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]1030 <li>The X86 backend generates inefficient floating point code when configured
1031 to generate code for systems that don't have SSE2.</li>
Duncan Sands47eff2b2008-06-08 19:38:43 +0000[diff] [blame]1032 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]1033 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]1034 runtime currently due to lack of support for the 'u' inline assembly
1035 constraint and for X87 floating point inline assembly.</li>
Dan Gohman8207ba92008-06-08 23:05:11 +0000[diff] [blame]1036 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]1037 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman8207ba92008-06-08 23:05:11 +0000[diff] [blame]1038 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1039</ul>
1040
1041</div>
1042
1043<!-- ======================================================================= -->
1044<div class="doc_subsection">
1045 <a name="ppc-be">Known problems with the PowerPC back-end</a>
1046</div>
1047
1048<div class="doc_text">
1049
1050<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000[diff] [blame]1051<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]1052compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1053</ul>
1054
1055</div>
1056
1057<!-- ======================================================================= -->
1058<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]1059 <a name="arm-be">Known problems with the ARM back-end</a>
1060</div>
1061
1062<div class="doc_text">
1063
1064<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]1065<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000[diff] [blame]1066processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]1067results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]1068<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]1069</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]1070</ul>
1071
1072</div>
1073
1074<!-- ======================================================================= -->
1075<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1076 <a name="sparc-be">Known problems with the SPARC back-end</a>
1077</div>
1078
1079<div class="doc_text">
1080
1081<ul>
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]1082<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]1083 support the 64-bit SPARC ABI (-m64).</li>
1084</ul>
1085
1086</div>
1087
1088<!-- ======================================================================= -->
1089<div class="doc_subsection">
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000[diff] [blame]1090 <a name="mips-be">Known problems with the MIPS back-end</a>
1091</div>
1092
1093<div class="doc_text">
1094
1095<ul>
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000[diff] [blame]1096<li>64-bit MIPS targets are not supported yet.</li>
1097</ul>
1098
1099</div>
1100
1101<!-- ======================================================================= -->
1102<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1103 <a name="alpha-be">Known problems with the Alpha back-end</a>
1104</div>
1105
1106<div class="doc_text">
1107
1108<ul>
1109
1110<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
1111appropriate nops inserted to ensure restartability.</li>
1112
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]1113</ul>
1114</div>
1115
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1116<!-- ======================================================================= -->
1117<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]1118 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1119</div>
1120
1121<div class="doc_text">
1122
1123<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]1124<li><a href="http://llvm.org/PR802">The C backend has only basic support for
1125 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000[diff] [blame]1126<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
1127 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif4906abe2009-03-02 12:02:51 +0000[diff] [blame]1128 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]1129<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands50723a92009-02-25 11:51:54 +0000[diff] [blame]1130<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1131</ul>
1132
1133</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]1134
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1135
1136<!-- ======================================================================= -->
1137<div class="doc_subsection">
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000[diff] [blame]1138 <a name="c-fe">Known problems with the llvm-gcc C and C++ front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1139</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]1140
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1141<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]1142
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]1143<p>The only major language feature of GCC not supported by llvm-gcc is
1144 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
1145 are only supported on some targets. For example, trampolines are only
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]1146 supported on some targets (these are used when you take the address of a
1147 nested function).</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1148
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1149</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1150
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1151<!-- ======================================================================= -->
1152<div class="doc_subsection">
Chris Lattner1eb4df62008-10-30 03:58:13 +0000[diff] [blame]1153 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
1154</div>
1155
1156<div class="doc_text">
Gabor Greifba10fe02008-11-04 21:50:59 +0000[diff] [blame]1157<ul>
Chris Lattner1eb4df62008-10-30 03:58:13 +0000[diff] [blame]1158<li>Fortran support generally works, but there are still several unresolved bugs
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]1159 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
1160 tools/gfortran component for details.</li>
Gabor Greifba10fe02008-11-04 21:50:59 +0000[diff] [blame]1161</ul>
Chris Lattner1eb4df62008-10-30 03:58:13 +0000[diff] [blame]1162</div>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1163
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1164<!-- ======================================================================= -->
1165<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]1166 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1167</div>
1168
1169<div class="doc_text">
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]1170The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
1171technology, and problems should be expected.
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1172<ul>
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]1173<li>The Ada front-end currently only builds on X86-32. This is mainly due
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]1174to lack of trampoline support (pointers to nested functions) on other platforms.
1175However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1176which does support trampolines.</li>
1177<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
Duncan Sands326a4982009-02-25 11:59:06 +0000[diff] [blame]1178This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
1179exception handling, which is used internally by the compiler.
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]1180Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
Duncan Sands978bcee2008-10-13 17:27:23 +0000[diff] [blame]1181<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
1182and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sands326a4982009-02-25 11:59:06 +0000[diff] [blame]1183(c380004 also fails with gcc-4.2 mainline).
1184If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
1185causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sandsdd3e6722009-03-02 16:35:57 +0000[diff] [blame]1186<li>Some GCC specific Ada tests continue to crash the compiler.</li>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]1187<li>The <tt>-E</tt> binder option (exception backtraces)
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1188<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]1189crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1190<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
1191or finish at a non-byte offset</a> in a record. Workaround: do not pack records
1192or use representation clauses that result in a field of a non-discrete type
1193starting or finishing in the middle of a byte.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]1194<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
1195'main' as generated by the Ada binder to be invalid</a>.
1196Workaround: hand edit the file to use pointers for <tt>argv</tt> and
1197<tt>envp</tt> rather than integers.</li>
1198<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
1199ignored</a>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1200</ul>
1201</div>
1202
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1203<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1204<div class="doc_section">
1205 <a name="additionalinfo">Additional Information</a>
1206</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1207<!-- *********************************************************************** -->
1208
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1209<div class="doc_text">
1210
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]1211<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]1212href="http://llvm.org">LLVM web page</a>, in particular in the <a
1213href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]1214contains versions of the API documentation which is up-to-date with the
1215Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]1216You can access versions of these documents specific to this release by going
1217into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1218
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1219<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]1220us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]1221lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1222
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1223</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1224
1225<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1226
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1227<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]1228<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]1229 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]1230 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]1231 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]1232 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]1233
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]1234 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1235 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]1236</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1237
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1238</body>
1239</html>