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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 7b91eda0de2223de5c66f3a0c0960c3b97fb8905 / . / docs / ReleaseNotes.html
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Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
3<html>
4<head>
Reid Spencer6454ed32004-11-18 18:38:58 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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"
14 width="136" height="136">
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 Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]78 strong phi elim
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]79 llvm.dbg.value: variable debug info for optimized code
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]80 loop dependence analysis
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]81 -->
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]82
Chris Lattner547a3912008-10-12 19:47:48 +0000[diff] [blame]83 <!-- for announcement email:
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]84 Logo web page.
85 llvm devmtg
86 compiler_rt
87 KLEE web page at klee.llvm.org
88 Many new papers added to /pubs/
Chris Lattnerdc910082010-03-17 06:41:58 +0000[diff] [blame]89 Mention gcc plugin.
Chris Lattner74c80df2009-02-25 06:34:50 +0000[diff] [blame]90 -->
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]91
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]92<!-- *********************************************************************** -->
93<div class="doc_section">
94 <a name="subproj">Sub-project Status Update</a>
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]95</div>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]96<!-- *********************************************************************** -->
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]97
98<div class="doc_text">
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]99<p>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]100The LLVM 2.7 distribution currently consists of code from the core LLVM
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]101repository (which roughly includes the LLVM optimizers, code generators
102and supporting tools), the Clang repository and the llvm-gcc repository. In
103addition to this code, the LLVM Project includes other sub-projects that are in
104development. Here we include updates on these subprojects.
Bill Wendling63d8c552009-03-02 04:28:57 +0000[diff] [blame]105</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]106
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]107</div>
108
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]109
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]110<!--=========================================================================-->
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]111<div class="doc_subsection">
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000[diff] [blame]112<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]113</div>
114
115<div class="doc_text">
116
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]117<p>The <a href="http://clang.llvm.org/">Clang project</a> is ...</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]118
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]119<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]120
Daniel Dunbar13739432008-10-14 23:25:09 +0000[diff] [blame]121<ul>
Daniel Dunbar60dadb62010-03-25 16:09:18 +0000[diff] [blame]122<li>FIXME: C++! Include a link to cxx_compatibility.html</li>
123
124<li>FIXME: Static Analyzer improvements?</li>
125
126<li>CIndex API and Python bindings: Clang now includes a C API as part of the
127CIndex library. Although we make make some changes to the API in the future, it
128is intended to be stable and has been designed for use by external projects. See
129the Clang
130doxygen <a href="http://clang.llvm.org/doxygen/group__CINDEX.html">CIndex</a>
131documentation for more details. The CIndex API also includings an preliminary
132set of Python bindings.</li>
133
134<li>ARM Support: Clang now has ABI support for both the Darwin and Linux ARM
135ABIs. Coupled with many improvements to the LLVM ARM backend, Clang is now
136suitable for use as a a beta quality ARM compiler.</li>
Bill Wendling6bc15282009-03-02 04:28:18 +0000[diff] [blame]137</ul>
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000[diff] [blame]138</div>
139
140<!--=========================================================================-->
141<div class="doc_subsection">
142<a name="clangsa">Clang Static Analyzer</a>
143</div>
144
145<div class="doc_text">
146
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]147<p>Previously announced in the 2.4, 2.5, and 2.6 LLVM releases, the Clang project also
Ted Kremenek8b3894c2009-02-27 07:01:32 +0000[diff] [blame]148includes an early stage static source code analysis tool for <a
149href="http://clang.llvm.org/StaticAnalysis.html">automatically finding bugs</a>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]150in C and Objective-C programs. The tool performs checks to find
Ted Kremenek8b3894c2009-02-27 07:01:32 +0000[diff] [blame]151bugs that occur on a specific path within a program.</p>
Chris Lattnercc042612008-10-14 00:52:49 +0000[diff] [blame]152
Chris Lattner0e464a92010-03-17 04:02:39 +0000[diff] [blame]153<p>In the LLVM 2.7 time-frame, the analyzer core has sprouted legs and...</p>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]154
155</div>
156
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]157<!--=========================================================================-->
158<div class="doc_subsection">
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000[diff] [blame]159<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]160</div>
161
162<div class="doc_text">
163<p>
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000[diff] [blame]164The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]165a JVM and a CLI Virtual Machine (Microsoft .NET is an
166implementation of the CLI) using LLVM for static and just-in-time
167compilation.</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]168
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]169<p>
Chris Lattnerbf8e5162010-03-29 18:34:13 +0000[diff] [blame]170With the release of LLVM 2.7, VMKit has shifted to a great framework for writing
171virtual machines. VMKit now offers precise and efficient garbage collection with
172multi-threading support, thanks to the MMTk memory management toolkit, as well
173as just in time and ahead of time compilation with LLVM. The major changes in
174VMKit 0.27 are:</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]175
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000[diff] [blame]176<ul>
177
Chris Lattnerbf8e5162010-03-29 18:34:13 +0000[diff] [blame]178<li>Garbage collection: VMKit now uses the MMTk toolkit for garbage collectors.
179 The first collector to be ported is the MarkSweep collector, which is precise,
180 and drastically improves the performance of VMKit.</li>
181<li>Line number information in the JVM: by using the debug metadata of LLVM, the
182 JVM now supports precise line number information, useful when printing a stack
183 trace.</li>
184<li>Interface calls in the JVM: we implemented a variant of the Interface Method
185 Table technique for interface calls in the JVM.
186</li>
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000[diff] [blame]187
188</ul>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]189</div>
190
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]191
192<!--=========================================================================-->
193<div class="doc_subsection">
194<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
195</div>
196
197<div class="doc_text">
198<p>
199The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
200is a simple library that provides an implementation of the low-level
201target-specific hooks required by code generation and other runtime components.
202For example, when compiling for a 32-bit target, converting a double to a 64-bit
203unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
204function. The compiler-rt library provides highly optimized implementations of
205this and other low-level routines (some are 3x faster than the equivalent
206libgcc routines).</p>
207
208<p>
209All of the code in the compiler-rt project is available under the standard LLVM
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]210License, a "BSD-style" license. New in LLVM 2.7: compiler_rt now
211supports ARM targets.</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]212
213</div>
214
215<!--=========================================================================-->
216<div class="doc_subsection">
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]217<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]218</div>
219
220<div class="doc_text">
221<p>
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]222<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
223gcc-4.5. Unlike llvm-gcc, which makes many intrusive changes to the underlying
224gcc-4.2 code, dragonegg in theory does not require any gcc-4.5 modifications
225whatsoever (currently one small patch is needed). This is thanks to the new
226<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>, which
227makes it possible to modify the behaviour of gcc at runtime by loading a plugin,
228which is nothing more than a dynamic library which conforms to the gcc plugin
229interface. DragonEgg is a gcc plugin that causes the LLVM optimizers to be run
230instead of the gcc optimizers, and the LLVM code generators instead of the gcc
231code generators, just like llvm-gcc. To use it, you add
232"-fplugin=path/dragonegg.so" to the gcc-4.5 command line, and gcc-4.5 magically
233becomes llvm-gcc-4.5!
234</p>
235
236<p>
237DragonEgg is still a work in progress. Currently C works very well, while C++,
238Ada and Fortran work fairly well. All other languages either don't work at all,
239or 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]240supported, and only on linux and darwin (darwin needs an additional gcc patch).
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]241</p>
242
243<p>
Duncan Sandscb9dda62010-04-21 13:51:48 +0000[diff] [blame]244DragonEgg is a new project which is seeing its first release with llvm-2.7.
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]245</p>
246
247</div>
248
249
250<!--=========================================================================-->
251<div class="doc_subsection">
252<a name="mc">llvm-mc: Machine Code Toolkit</a>
253</div>
254
255<div class="doc_text">
256<p>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]257The LLVM Machine Code (MC) Toolkit project is ...
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]258</p>
259
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]260<p>
261MC Disassembler (with blog post), MCInstPrinter. Many X86 backend and AsmPrinter simplifications
262Can transcode from GAS to intel syntax with "llvm-mc foo.s -output-asm-variant=1"
263</p>
264
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]265</div>
266
267
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]268<!-- *********************************************************************** -->
269<div class="doc_section">
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]270 <a name="externalproj">External Open Source Projects Using LLVM 2.7</a>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]271</div>
272<!-- *********************************************************************** -->
273
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]274<div class="doc_text">
275
276<p>An exciting aspect of LLVM is that it is used as an enabling technology for
277 a lot of other language and tools projects. This section lists some of the
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]278 projects that have already been updated to work with LLVM 2.7.</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]279</div>
280
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]281<!--=========================================================================-->
282<div class="doc_subsection">
283<a name="pure">Pure</a>
284</div>
285
286<div class="doc_text">
287<p>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]288<a href="http://pure-lang.googlecode.com/">Pure</a>
289is an algebraic/functional programming language based on term rewriting.
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]290Programs are collections of equations which are used to evaluate expressions in
291a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]292lexical closures, a hygienic macro system (also based on term rewriting),
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]293built-in list and matrix support (including list and matrix comprehensions) and
294an easy-to-use C interface. The interpreter uses LLVM as a backend to
295 JIT-compile Pure programs to fast native code.</p>
296
Chris Lattner477a1fd2010-03-17 17:25:49 +0000[diff] [blame]297<p>Pure versions 0.43 and later have been tested and are known to work with
298LLVM 2.7 (and continue to work with older LLVM releases >= 2.5).</p>
299
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]300</div>
301
Chris Lattnerbc31caf2009-02-28 18:58:01 +0000[diff] [blame]302<!--=========================================================================-->
303<div class="doc_subsection">
304<a name="RoadsendPHP">Roadsend PHP</a>
305</div>
306
307<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]308<p>
309<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
Chris Lattnercade8222009-03-02 19:07:24 +0000[diff] [blame]310source implementation of the PHP programming
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]311language that uses LLVM for its optimizer, JIT and static compiler. This is a
Chris Lattner0e464a92010-03-17 04:02:39 +0000[diff] [blame]312reimplementation of an earlier project that is now based on LLVM.
Chris Lattner477a1fd2010-03-17 17:25:49 +0000[diff] [blame]313</p>
Chris Lattnerbc31caf2009-02-28 18:58:01 +0000[diff] [blame]314</div>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]315
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]316<!--=========================================================================-->
317<div class="doc_subsection">
318<a name="UnladenSwallow">Unladen Swallow</a>
319</div>
320
321<div class="doc_text">
322<p>
323<a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
324branch of <a href="http://python.org/">Python</a> intended to be fully
325compatible and significantly faster. It uses LLVM's optimization passes and JIT
Chris Lattnerb5f6feb2010-03-18 06:52:15 +0000[diff] [blame]326compiler.
Chris Lattner0e464a92010-03-17 04:02:39 +0000[diff] [blame]327</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]328</div>
329
330<!--=========================================================================-->
331<div class="doc_subsection">
Chris Lattner8d4bbbe2010-03-29 17:50:39 +0000[diff] [blame]332<a name="tce">TTA-based Codesign Environment (TCE)</a>
333</div>
334
335<div class="doc_text">
336<p>
337<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing
338application-specific processors (ASP) based on the Transport triggered
339architecture (TTA). The toolset provides a complete co-design flow from C/C++
340programs down to synthesizable VHDL and parallel program binaries. Processor
341customization points include the register files, function units, supported
342operations, and the interconnection network.</p>
343
344<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target
345independent optimizations and also for parts of code generation. It generates
346new LLVM-based code generators "on the fly" for the designed TTA processors and
347loads them in to the compiler backend as runtime libraries to avoid per-target
348recompilation of larger parts of the compiler chain.</p>
349
350</div>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]351
John Criswellf77cdab2010-04-06 14:52:14 +0000[diff] [blame]352<!--=========================================================================-->
353<div class="doc_subsection">
354<a name="safecode">SAFECode Compiler</a>
355</div>
356
357<div class="doc_text">
358<p>
359<a href="http://safecode.cs.illinois.edu">SAFECode</a> is a memory safe C
360compiler built using LLVM. It takes standard, unannotated C code, analyzes the
361code to ensure that memory accesses and array indexing operations are safe, and
362instruments the code with run-time checks when safety cannot be proven
363statically.
364</p>
365</div>
366
367
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]368<!-- *********************************************************************** -->
369<div class="doc_section">
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]370 <a name="whatsnew">What's New in LLVM 2.7?</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]371</div>
372<!-- *********************************************************************** -->
373
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]374<div class="doc_text">
375
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]376<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]377minor improvements. Some of the major improvements and new features are listed
378in this section.
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]379</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]380
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]381<p>In addition to changes to the code, between LLVM 2.6 and 2.7, a number of
382organization changes have happened:
383</p>
384
385<ul>
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]386<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]387
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]388<li>Ted Kremenek and Doug Gregor have stepped forward as <a
389 href="http://llvm.org/docs/DeveloperPolicy.html#owners">Code Owners</a> of the
390 Clang static analyzer and the Clang Frontend, respectively.</li>
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]391
392<li>LLVM now has an <a href="http://blog.llvm.org">official Blog</a> at
393 <a href="http://blog.llvm.org">http://blog.llvm.org</a>. This is a great way
394 to learn about new LLVM-related features as they are implemented. Several
395 features in this release are already explained on the blog.</li>
396
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]397<li>The LLVM web pages are now checked into the SVN server, in the "www",
398 "www-pubs" and "www-releases" SVN modules. Previously they were hidden in a
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]399 largely inaccessible old CVS server.</li>
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]400
401<li><a href="http://llvm.org">llvm.org</a> is now hosted on a new (and much
402 faster) server. It is still graciously hosted at the University of Illinois
403 of Urbana Champaign.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]404</ul>
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]405</div>
406
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]407<!--=========================================================================-->
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]408<div class="doc_subsection">
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]409<a name="majorfeatures">Major New Features</a>
410</div>
411
412<div class="doc_text">
413
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]414<p>LLVM 2.7 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]415
416<ul>
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]417<li>2.7 includes initial support for the <a
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]418 href="http://en.wikipedia.org/wiki/MicroBlaze">MicroBlaze</a> target.
419 MicroBlaze is a soft processor core designed for Xilinx FPGAs.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]420
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]421<li>2.7 includes a new LLVM IR "extensible metadata" feature. This feature
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]422 supports many different use cases, including allowing front-end authors to
423 encode source level information into LLVM IR, which is consumed by later
424 language-specific passes. This is a great way to do high-level optimizations
425 like devirtualization, type-based alias analysis, etc. See the <a
426 href="http://blog.llvm.org/2010/04/extensible-metadata-in-llvm-ir.html">
427 Extensible Metadata Blog Post</a> for more information.</li>
428
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]429<li>2.7 encodes <a href="SourceLevelDebugging.html">debug information</a>
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]430in a completely new way, built on extensible metadata. The new implementation
431is much more memory efficient and paves the way for improvements to optimized
432code debugging experience.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]433
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]434<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]435 indirect branch through a pointer. This is particularly useful for
436 interpreter loops, and is used to implement the GCC "address of label"
437 extension. For more information, see the <a
438href="http://blog.llvm.org/2010/01/address-of-label-and-indirect-branches.html">
439Address of Label and Indirect Branches in LLVM IR Blog Post</a>.
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]440
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]441<li>2.7 is the first release to start supporting APIs for assembling and
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]442 disassembling target machine code. These APIs are useful for a variety of
443 low level clients, and are surfaced in the new "enhanced disassembly" API.
444 For more information see the <a
445 href="http://blog.llvm.org/2010/01/x86-disassembler.html">The X86
446 Disassembler Blog Post</a> for more information.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]447
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]448<li>2.7 includes major parts of the work required by the new MC Project,
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]449 which aims to rework our handling of low-level machine code. A few targets
450 have been refactored to support it, and work is underway to support a native
451 assembler in LLVM. This work is not complete in LLVM 2.7, but you has made
452 substantially more progress on LLVM mainline. You can read more about this
453 in the <a href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">
454 Intro to the LLVM MC Project Blog Post</a>.
455</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]456
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]457</ul>
Chris Lattnerdc910082010-03-17 06:41:58 +0000[diff] [blame]458
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]459</div>
460
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]461<!--=========================================================================-->
462<div class="doc_subsection">
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]463<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]464</div>
465
466<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]467<p>LLVM IR has several new features for better support of new targets and that
468expose new optimization opportunities:</p>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]469
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]470<ul>
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]471<li>LLVM IR now supports a 16-bit "half float" data type through <a
472 href="LangRef.html#int_fp16">two new intrinsics</a> and APFloat support.</li>
473<li>LLVM IR supports two new <a href="LangRef.html#fnattrs">function
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]474 attributes</a>: inlinehint and alignstack(n). The former is a hint to the
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]475 optimizer that a function was declared 'inline' and thus the inliner should
476 weight it higher when considering inlining it. The later
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]477 indicates to the code generator that the function diverges from the platform
478 ABI on stack alignment.</li>
479<li>The new <a href="LangRef.html#int_objectsize">llvm.objectsize</a> intrinsic
480 allows the optimizer to infer the sizes of memory objects in some cases.
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]481 This intrinsic is used to implement the GCC <tt>__builtin_object_size</tt>
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]482 extension.</li>
483<li>LLVM 2.7 has pre-alpha support for <a
484 href="http://llvm.org/docs/LangRef.html#t_union">unions in LLVM IR</a>.
485 Unfortuantely, this support is not really usable in 2.7, so if you're
486 interested in pushing it forward, please help contribute to LLVM mainline.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]487</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]488</ul>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]489
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]490</div>
491
492<!--=========================================================================-->
493<div class="doc_subsection">
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]494<a name="optimizer">Optimizer Improvements</a>
495</div>
496
497<div class="doc_text">
498
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]499<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]500release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]501
502<ul>
503
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]504<li>The inliner reuses now merges arrays stack objects in different callees when
505 inlining multiple call sites into one function. This reduces the stack size
506 of the resultant function.</li>
507<li>The -basicaa alias analysis pass (which is the default) has been improved to
508 be less dependent on "type safe" pointers. It can now look through bitcasts
509 and other constructs more aggressively, allowing better load/store
510 optimization.</li>
511<li>The load elimination optimization in the GVN Pass [<a
512href="http://blog.llvm.org/2009/12/introduction-to-load-elimination-in-gvn.html">intro
513 blog post</a>] has been substantially improved to be more aggressive about
514 partial redundancy elimination and do more aggressive phi translation. Please
515 see the <a
516 href="http://blog.llvm.org/2009/12/advanced-topics-in-redundant-load.html">
517 Advanced Topics in Redundant Load Elimination with a Focus on PHI Translation
518 Blog Post</a> for more details.</li>
519<li>The module <a href="LangRef.html#datalayout">target data string</a> now
520 includes a notion of what the 'native' integer data types a for the target,
521 which allows various optimizations to use. This helps mid-level
522 optimizations avoid promoting complex sequences of operations to data types
523 that are not natively supported (e.g. converting i32 operations to i64 on
524 a 32-bit chip).</li>
525<li>The mid-level optimizer is now conservative when operating on a module with
526 no target data. Previously, it would default to SparcV9 settings, which is
527 not what most people expected.</li>
Chris Lattnera54c1f72010-04-21 06:42:24 +0000[diff] [blame]528<li>Jump threading is now much more aggressive at simplifying correlated
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]529 conditionals and threading blocks with otherwise complex logic. It has
530 subsumed the old "Conditional Propagation" pass, and -condprop has been
531 removed from LLVM 2.7.</li>
532<li>The -instcombine pass has been refactored from being one huge file to being
533 a library of its own. Internally, it uses a customized IRBuilder to clean
534 it up and simplify it.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]535
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]536<li>The optimal edge profiling pass is reliable and much more complete than in
537 2.6. It can be used with the llvm-prof tool but isn't wired up to the
538 llvm-gcc and clang command line options yet.</li>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]539
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]540<li>A new experimental alias analysis implementation, -scev-aa, has been added.
541 It uses LLVM's Scalar Evolution implementation to do symbolic analysis of
542 pointer offset expressions to disambiguate pointers. It can catch a few
543 cases that basicaa cannot, particularly in complex loop nests.</li>
Chris Lattnera54c1f72010-04-21 06:42:24 +0000[diff] [blame]544
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]545<li>As usual, there are countless minor optimization improvements and bug fixes,
546 and the default pass ordering has been tweaked for improved optimization
547 effectiveness.</li>
Chris Lattnera54c1f72010-04-21 06:42:24 +0000[diff] [blame]548
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]549</ul>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]550
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]551</div>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]552
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]553
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]554<!--=========================================================================-->
555<div class="doc_subsection">
556<a name="executionengine">Interpreter and JIT Improvements</a>
557</div>
Chris Lattnerf3013872008-10-13 21:50:36 +0000[diff] [blame]558
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]559<div class="doc_text">
560
561<ul>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]562<li>The JIT now supports generating debug information, which is compatible with
563the new GDB 7.0 (and later) interfaces for registering debug info for
564dynamically generated code.</li>
565
Jeffrey Yasskin01eba392010-01-29 19:10:38 +0000[diff] [blame]566<li>The JIT now <a
567href="http://llvm.org/viewvc/llvm-project?view=rev&revision=85295">defaults
568to compiling eagerly</a> to avoid a race condition in the lazy JIT.
569Clients that still want the lazy JIT can switch it on by calling
570<tt>ExecutionEngine::DisableLazyCompilation(false)</tt>.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]571
Jeffrey Yasskin40966a72010-02-11 01:07:39 +0000[diff] [blame]572<li>It is now possible to create more than one JIT instance in the same process.
573These JITs can generate machine code in parallel,
574although <a href="http://llvm.org/docs/ProgrammersManual.html#jitthreading">you
575still have to obey the other threading restrictions</a>.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]576
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]577</ul>
578
579</div>
580
581<!--=========================================================================-->
582<div class="doc_subsection">
Chris Lattner511433e2009-03-02 03:24:11 +0000[diff] [blame]583<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]584</div>
585
586<div class="doc_text">
587
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]588<p>We have put a significant amount of work into the code generator
589infrastructure, which allows us to implement more aggressive algorithms and make
590it run faster:</p>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]591
592<ul>
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]593<li>New instruction selector [blog post?].</li>
Chris Lattnera54c1f72010-04-21 06:42:24 +0000[diff] [blame]594<li>New LSR with "full strength reduction" mode. Description?</li>
595<li>Code generator MC'ized except for debug info and EH.</li>
596<li>New CodeGen Level CSE</li>
597<li>Combiner-AA improvements, why not on by default?</li>
598<li>Pre-regalloc tail duplication</li>
599<li>Codegen level OptimizeExtsPass pass, takes advantage of x86 subregs. </li>
600<li>Support for the GCC option -fno-schedule-insns</li>
601<li>Non-temporal load/store, only implemented on X86, see LangRef.html#i_load.</li>
602<li>MachineSSAUpdater.h</li>
603<li>X86 and XCore supports returning arbitrary return values, returning too many values is
604 supported by returning through a hidden pointer.</li>
605<li>verbose-asm now produces information about spill slots and loop nests</li>
606<li>GHC Haskell ABI / calling conv support.</li>
607<li>Many improvements to debug info</li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]608</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]609</div>
610
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]611<!--=========================================================================-->
612<div class="doc_subsection">
613<a name="x86">X86-32 and X86-64 Target Improvements</a>
614</div>
615
616<div class="doc_text">
617<p>New features of the X86 target include:
618</p>
619
620<ul>
Chris Lattnera54c1f72010-04-21 06:42:24 +0000[diff] [blame]621<li>The X86 backend now optimizes tails calls much more aggressively for
622 functions that use the standard C calling convention.</li>
623<li>The X86 backend now models scalar SSE registers as subregs of the SSE vector
624 registers, making the code generator more aggressive in cases where scalars
625 and vector types are mixed.</li>
Chris Lattner511433e2009-03-02 03:24:11 +0000[diff] [blame]626
Chris Lattnera54c1f72010-04-21 06:42:24 +0000[diff] [blame]627<li>PostRA scheduler for X86? FIXME: is this on by default in 2.7?</li>
Chris Lattner511433e2009-03-02 03:24:11 +0000[diff] [blame]628
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]629</ul>
630
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]631</div>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]632
633<!--=========================================================================-->
634<div class="doc_subsection">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]635<a name="ARM">ARM Target Improvements</a>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]636</div>
637
638<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]639<p>New features of the ARM target include:
640</p>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]641
642<ul>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]643
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]644<li>The ARM backend now generates instructions in unified assembly syntax.</li>
645
646<li>llvm-gcc now has complete support for the ARM v7 NEON instruction set. This
647 support differs slightly from the GCC implementation. Please see the
648 <a
649href="http://blog.llvm.org/2010/04/arm-advanced-simd-neon-intrinsics-and.html">
650 ARM Advanced SIMD (NEON) Intrinsics and Types in LLVM Blog Post</a> for
651 helpful information if migrating code from GCC to LLVM-GCC.</li>
652
653<li>The ARM and Thumb code generators now using register scavenging for stack
654 object address materialization.(FIXME: WHAT BENEFIT DOES THIS PROVIDE?)</li>
655
656<li>The ARM backend now has good support for ARMv4 targets, and has been tested
657 on StrongARM hardware. Previously, LLVM only supported ARMv4T and
658 newer chips.</li>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]659</ul>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]660
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]661
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]662</div>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]663
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]664<!--=========================================================================-->
665<div class="doc_subsection">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]666<a name="newapis">New Useful APIs</a>
667</div>
668
669<div class="doc_text">
670
671<p>This release includes a number of new APIs that are used internally, which
672 may also be useful for external clients.
673</p>
674
675<ul>
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame^]676<li>The optimizer uses the new CodeMetrics class to measure the size of code.
677 Various passes that use thing (like the inliner, loop unswitcher, etc) all
678 use this to make more accurate estimates of the code size impact of various
679 optimizations.</li>
680<li>A new <a href="http://llvm.org/doxygen/InstructionSimplify_8h-source.html">
681 llvm/Analysis/InstructionSimplify.h</a> interface available for doing
682 symbolic simplification of instructions (e.g. <tt>a+0</tt> -&gt; <tt>a</tt>)
683 without requiring the instruction to exist. This centralizes a lot of
684 ad-hoc symbolic manipulation code scattered in various passes.</li>
685<li>The optimizer now uses a new <a
686 href="http://llvm.org/doxygen/SSAUpdater_8h-source.html">SSAUpdater</a>
687 class which efficiently supports
688 doing unstructured SSA update operations. This centralized a bunch of code
689 scattered through various passes (e.g. jump threading, lcssa, loop rotate,
690 etc) for doing this sort of thing. The code generator has an similar
691 <a href="http://llvm.org/doxygen/MachineSSAUpdater_8h-source.html">
692 MachineSSAUpdater</a> class.</li>
693<li>The <a href="http://llvm.org/doxygen/Regex_8h-source.html">
694 llvm/Support/Regex.h</a> header exposes a platform independent regular
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]695 expression API. Building on this, the <a
696 href="TestingGuide.html#FileCheck">FileCheck</a> utility now supports
697 regular exressions.</li>
698<li>raw_ostream now supports a circular "debug stream" accessed with "dbgs()".
699 By default, this stream works the same way as "errs()", but if you pass
700 <tt>-debug-buffer-size=1000</tt> to opt, the debug stream is capped to a
701 fixed sized circular buffer and the output is printed at the end of the
702 program's execution. This is helpful if you have a long lived compiler
703 process and you're interested in seeing snapshots in time.</li>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]704</ul>
705
706
707</div>
708
709<!--=========================================================================-->
710<div class="doc_subsection">
711<a name="otherimprovements">Other Improvements and New Features</a>
712</div>
713
714<div class="doc_text">
715<p>Other miscellaneous features include:</p>
716
717<ul>
Chris Lattner450a31e2010-04-21 06:23:40 +0000[diff] [blame]718<li>You can now build LLVM as a big dynamic library (e.g. "libllvm2.7.so"). To
719 get this, configure LLVM with the --enable-shared option.</li>
720
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]721<li>LLVM command line tools now overwrite their output by default, before they
722 would only do this with -f. This makes them more convenient to use, and
723 behave more like standard unix tools.</li>
724
725<li>The opt and llc tools now autodetect whether their input is a .ll or .bc
726 file, and automatically do the right thing. This means you don't need to
727 explicitly use the llvm-as tool for most things.</li>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]728</ul>
729
730</div>
731
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]732
733<!--=========================================================================-->
734<div class="doc_subsection">
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]735<a name="changes">Major Changes and Removed Features</a>
736</div>
737
738<div class="doc_text">
739
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]740<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]741on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]742from the previous release.</p>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]743
744<ul>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]745
746<li>
747The Andersen's alias analysis ("anders-aa") pass, the Predicate Simplifier
748("predsimplify") pass, the LoopVR pass, the GVNPRE pass, and the random sampling
749profiling ("rsprofiling") passes have all been removed. They were not being
750actively maintained and had substantial problems. If you are interested in
751these components, you are welcome to ressurect them from SVN, fix the
752correctness problems, and resubmit them to mainline.</li>
753
754<li>LLVM now defaults to building most libraries with RTTI turned off, providing
755a code size reduction. Packagers who are interested in building LLVM to support
756plugins that require RTTI information should build with "make REQUIRE_RTTI=1"
757and should read the new <a href="Packaging.html">Advice on Packaging LLVM</a>
758document.</li>
759
Jeffrey Yasskinbc83d062010-02-09 23:03:44 +0000[diff] [blame]760<li>The LLVM interpreter now defaults to <em>not</em> using <tt>libffi</tt> even
761if you have it installed. This makes it more likely that an LLVM built on one
762system will work when copied to a similar system. To use <tt>libffi</tt>,
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]763configure with <tt>--enable-libffi</tt></li>.
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]764
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]765<li>Debug information uses a completely different representation, an LLVM 2.6
766.bc file should work with LLVM 2.7, but debug info won't come forward.</li>
767
768<li>The LLVM 2.6 (and earlier) "malloc" and "free" instructions got removed,
769 along with LowerAllocations pass. Now you should just use a call to the
770 malloc and free functions in libc. These calls are optimized as well as
771 the old instructions were.</li>
772</ul>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]773
774<p>In addition, many APIs have changed in this release. Some of the major LLVM
775API changes are:</p>
776
777<ul>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]778<li>Just about everything has been converted to use raw_ostream instead of
779 std::ostream.</li>
780<li>llvm/ADT/iterator.h has been removed, just use &lt;iterator&gt;
781 instead.</li>
782<li>The Streams.h file and "DOUT" got removed, use "DEBUG(errs() &lt;&lt; ...);"
783 instead.</li>
Jeffrey Yasskin4fcd6072010-01-28 01:41:20 +0000[diff] [blame]784<li><tt>ModuleProvider</tt> has been <a
785href="http://llvm.org/viewvc/llvm-project?view=rev&revision=94686">removed</a>
786and its methods moved to <tt>Module</tt> and <tt>GlobalValue</tt>.
787Most clients can remove uses of <tt>ExistingModuleProvider</tt>,
788replace <tt>getBitcodeModuleProvider</tt> with
789<tt>getLazyBitcodeModule</tt>, and pass their <tt>Module</tt> to
790functions that used to accept <tt>ModuleProvider</tt>. Clients who
791wrote their own <tt>ModuleProvider</tt>s will need to derive from
792<tt>GVMaterializer</tt> instead and use
793<tt>Module::setMaterializer</tt> to attach it to a
794<tt>Module</tt>.</li>
795
796<li><tt>GhostLinkage</tt> has given up the ghost.
797<tt>GlobalValue</tt>s that have not yet been read from their backing
798storage have the same linkage they will have after being read in.
799Clients must replace calls to
800<tt>GlobalValue::hasNotBeenReadFromBitcode</tt> with
801<tt>GlobalValue::isMaterializable</tt>.</li>
Daniel Dunbar4acdede2010-02-10 04:09:52 +0000[diff] [blame]802
Daniel Dunbarca1c8162010-02-14 01:47:19 +0000[diff] [blame]803<li>The <tt>llvm/Support/DataTypes.h</tt> header has moved
804to <tt>llvm/System/DataTypes.h</tt>.</li>
805
Duncan Sands411432d2010-02-17 17:20:17 +0000[diff] [blame]806<li>The <tt>isInteger</tt>, <tt>isIntOrIntVector</tt>, <tt>isFloatingPoint</tt>,
807<tt>isFPOrFPVector</tt> and <tt>isFPOrFPVector</tt> methods have been renamed
808<tt>isIntegerTy</tt>, <tt>isIntOrIntVectorTy</tt>, <tt>isFloatingPointTy</tt>,
809<tt>isFPOrFPVectorTy</tt> and <tt>isFPOrFPVectorTy</tt> respectively.</li>
Devang Patelb34dd132008-10-14 20:03:43 +0000[diff] [blame]810</ul>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]811
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]812</div>
813
814
815
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]816<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]817<div class="doc_section">
818 <a name="portability">Portability and Supported Platforms</a>
819</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]820<!-- *********************************************************************** -->
821
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]822<div class="doc_text">
823
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]824<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]825
826<ul>
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]827<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]828 Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like
829 systems).</li>
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]830<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]831 and 64-bit modes.</li>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]832<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]833<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
834 support is available for native builds with Visual C++).</li>
Chris Lattner7e23d6e2009-10-16 16:30:58 +0000[diff] [blame]835<li>Sun x86 and AMD64 machines running Solaris 10, OpenSolaris 0906.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]836<li>Alpha-based machines running Debian GNU/Linux.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]837</ul>
838
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]839<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]840to the machine and operating system on which it is built. However, minor
841porting may be required to get LLVM to work on new platforms. We welcome your
842portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]843
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]844</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]845
846<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]847<div class="doc_section">
848 <a name="knownproblems">Known Problems</a>
849</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]850<!-- *********************************************************************** -->
851
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]852<div class="doc_text">
853
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]854<p>This section contains significant known problems with the LLVM system,
Chris Lattnere18b32e2008-11-10 05:40:34 +0000[diff] [blame]855listed by component. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]856href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]857there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]858
Chris Lattner477a1fd2010-03-17 17:25:49 +0000[diff] [blame]859<ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]860<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
861using the stock GCC 3.x.x series 'out the box',
Chris Lattner554ee4a2009-11-03 21:50:09 +0000[diff] [blame]862See: <a href="GettingStarted.html#brokengcc">Broken versions of GCC and other tools</a>.
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]863However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
864for x86/x86-64 has been made available from the third party AuroraUX Project
865that has been meticulously tested for bootstrapping LLVM &amp; Clang.</li>
866</ul>
867
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]868</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]869
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]870<!-- ======================================================================= -->
871<div class="doc_subsection">
872 <a name="experimental">Experimental features included with this release</a>
873</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]874
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]875<div class="doc_text">
876
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]877<p>The following components of this LLVM release are either untested, known to
878be broken or unreliable, or are in early development. These components should
879not be relied on, and bugs should not be filed against them, but they may be
880useful 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]881components, please contact us on the <a
882href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]883
884<ul>
Wesley Peck7c4a1212010-03-18 14:31:30 +0000[diff] [blame]885<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
886 backends are experimental.</li>
Bill Wendling99dac472009-03-02 07:54:14 +0000[diff] [blame]887<li>The <tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000[diff] [blame]888 supported value for this option. The MachO writer is experimental, and
889 works much better in mainline SVN.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]890</ul>
891
892</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]893
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]894<!-- ======================================================================= -->
895<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]896 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]897</div>
898
899<div class="doc_text">
900
901<ul>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]902 <li>The X86 backend does not yet support
903 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
904 floating point stack</a>. It supports the 'f' and 't' constraints, but not
905 'u'.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]906 <li>The X86 backend generates inefficient floating point code when configured
907 to generate code for systems that don't have SSE2.</li>
Duncan Sands47eff2b2008-06-08 19:38:43 +0000[diff] [blame]908 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]909 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
910 runtime currently due
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]911 to <a href="http://llvm.org/PR2255">several</a>
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]912 <a href="http://llvm.org/PR2257">bugs</a> and due to lack of support for
913 the
914 'u' inline assembly constraint and for X87 floating point inline assembly.</li>
Dan Gohman8207ba92008-06-08 23:05:11 +0000[diff] [blame]915 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]916 <tt>va_arg</tt>. Currently, the llvm-gcc and front-ends support variadic
Dan Gohman8207ba92008-06-08 23:05:11 +0000[diff] [blame]917 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]918</ul>
919
920</div>
921
922<!-- ======================================================================= -->
923<div class="doc_subsection">
924 <a name="ppc-be">Known problems with the PowerPC back-end</a>
925</div>
926
927<div class="doc_text">
928
929<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000[diff] [blame]930<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]931compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]932</ul>
933
934</div>
935
936<!-- ======================================================================= -->
937<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]938 <a name="arm-be">Known problems with the ARM back-end</a>
939</div>
940
941<div class="doc_text">
942
943<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]944<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000[diff] [blame]945processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]946results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]947<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]948</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]949</ul>
950
951</div>
952
953<!-- ======================================================================= -->
954<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]955 <a name="sparc-be">Known problems with the SPARC back-end</a>
956</div>
957
958<div class="doc_text">
959
960<ul>
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]961<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]962 support the 64-bit SPARC ABI (-m64).</li>
963</ul>
964
965</div>
966
967<!-- ======================================================================= -->
968<div class="doc_subsection">
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000[diff] [blame]969 <a name="mips-be">Known problems with the MIPS back-end</a>
970</div>
971
972<div class="doc_text">
973
974<ul>
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000[diff] [blame]975<li>64-bit MIPS targets are not supported yet.</li>
976</ul>
977
978</div>
979
980<!-- ======================================================================= -->
981<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]982 <a name="alpha-be">Known problems with the Alpha back-end</a>
983</div>
984
985<div class="doc_text">
986
987<ul>
988
989<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
990appropriate nops inserted to ensure restartability.</li>
991
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]992</ul>
993</div>
994
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]995<!-- ======================================================================= -->
996<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]997 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]998</div>
999
1000<div class="doc_text">
1001
1002<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]1003<li><a href="http://llvm.org/PR802">The C backend has only basic support for
1004 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000[diff] [blame]1005<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
1006 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif4906abe2009-03-02 12:02:51 +0000[diff] [blame]1007 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]1008<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands50723a92009-02-25 11:51:54 +0000[diff] [blame]1009<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1010</ul>
1011
1012</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]1013
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1014
1015<!-- ======================================================================= -->
1016<div class="doc_subsection">
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000[diff] [blame]1017 <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]1018</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]1019
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1020<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]1021
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]1022<p>The only major language feature of GCC not supported by llvm-gcc is
1023 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
1024 are only supported on some targets. For example, trampolines are only
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]1025 supported on some targets (these are used when you take the address of a
1026 nested function).</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1027
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]1028<p>If you run into GCC extensions which are not supported, please let us know.
1029</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1030
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1031</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1032
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1033<!-- ======================================================================= -->
1034<div class="doc_subsection">
Chris Lattner1eb4df62008-10-30 03:58:13 +0000[diff] [blame]1035 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
1036</div>
1037
1038<div class="doc_text">
Gabor Greifba10fe02008-11-04 21:50:59 +0000[diff] [blame]1039<ul>
Chris Lattner1eb4df62008-10-30 03:58:13 +0000[diff] [blame]1040<li>Fortran support generally works, but there are still several unresolved bugs
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]1041 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
1042 tools/gfortran component for details.</li>
Gabor Greifba10fe02008-11-04 21:50:59 +0000[diff] [blame]1043</ul>
Chris Lattner1eb4df62008-10-30 03:58:13 +0000[diff] [blame]1044</div>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1045
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1046<!-- ======================================================================= -->
1047<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]1048 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1049</div>
1050
1051<div class="doc_text">
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]1052The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
1053technology, and problems should be expected.
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1054<ul>
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]1055<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]1056to lack of trampoline support (pointers to nested functions) on other platforms.
1057However, 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]1058which does support trampolines.</li>
1059<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]1060This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
1061exception handling, which is used internally by the compiler.
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]1062Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
Duncan Sands978bcee2008-10-13 17:27:23 +0000[diff] [blame]1063<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
1064and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sands326a4982009-02-25 11:59:06 +0000[diff] [blame]1065(c380004 also fails with gcc-4.2 mainline).
1066If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
1067causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sandsdd3e6722009-03-02 16:35:57 +0000[diff] [blame]1068<li>Some GCC specific Ada tests continue to crash the compiler.</li>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]1069<li>The <tt>-E</tt> binder option (exception backtraces)
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1070<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]1071crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1072<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
1073or finish at a non-byte offset</a> in a record. Workaround: do not pack records
1074or use representation clauses that result in a field of a non-discrete type
1075starting or finishing in the middle of a byte.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]1076<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
1077'main' as generated by the Ada binder to be invalid</a>.
1078Workaround: hand edit the file to use pointers for <tt>argv</tt> and
1079<tt>envp</tt> rather than integers.</li>
1080<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
1081ignored</a>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1082</ul>
1083</div>
1084
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1085<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1086<div class="doc_section">
1087 <a name="additionalinfo">Additional Information</a>
1088</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1089<!-- *********************************************************************** -->
1090
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1091<div class="doc_text">
1092
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]1093<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]1094href="http://llvm.org">LLVM web page</a>, in particular in the <a
1095href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]1096contains versions of the API documentation which is up-to-date with the
1097Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]1098You can access versions of these documents specific to this release by going
1099into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1100
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1101<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]1102us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]1103lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1104
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1105</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1106
1107<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1108
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1109<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]1110<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]1111 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]1112 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]1113 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]1115
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]1116 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1117 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]1118</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1119
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1120</body>
1121</html>