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gerrit-public.fairphone.software / toolchain / llvm-project / ad2804110b716caf604775b41375e838cbf75554 / . / llvm / docs / ReleaseNotes.html
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Misha Brukman80731b92003-11-22 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 Spencere4190fa2004-11-18 18:38:58 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]6 <link rel="stylesheet" href="llvm.css" type="text/css">
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]7 <title>LLVM 2.7 Release Notes</title>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]8</head>
9<body>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]10
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]11<div class="doc_title">LLVM 2.7 Release Notes</div>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]12
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]13<img align=right src="http://llvm.org/img/DragonSmall.png"
Gabor Greif27b166352010-04-22 10:21:43 +0000[diff] [blame]14 width="136" height="136" alt="LLVM Dragon Logo">
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]15
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]16<ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#intro">Introduction</a></li>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]18 <li><a href="#subproj">Sub-project Status Update</a></li>
Jeffrey Yasskin0830b972010-01-28 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 Lattner77a51732004-04-30 22:17:12 +0000[diff] [blame]21 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]22 <li><a href="#portability">Portability and Supported Platforms</a></li>
Dan Gohmanad888912008-10-14 16:23:02 +0000[diff] [blame]23 <li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]24 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]25</ol>
26
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]27<div class="doc_author">
Dan Gohmanad888912008-10-14 16:23:02 +0000[diff] [blame]28 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]29</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]30
Chris Lattner06971182010-04-13 06:37:00 +0000[diff] [blame]31<!--
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]32<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.8
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]33release.<br>
34You may prefer the
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]35<a href="http://llvm.org/releases/2.6/docs/ReleaseNotes.html">LLVM 2.7
Chris Lattner06971182010-04-13 06:37:00 +0000[diff] [blame]36Release Notes</a>.</h1>-->
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]37
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]38<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]39<div class="doc_section">
40 <a name="intro">Introduction</a>
41</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]42<!-- *********************************************************************** -->
43
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]44<div class="doc_text">
45
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]46<p>This document contains the release notes for the LLVM Compiler
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]47Infrastructure, release 2.7. Here we describe the status of LLVM, including
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]48major improvements from the previous release and significant known problems.
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]49All LLVM releases may be downloaded from the <a
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]50href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]51
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]52<p>For more information about LLVM, including information about the latest
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]53release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattnere7525b52003-10-07 21:38:31 +0000[diff] [blame]54web site</a>. If you have questions or comments, the <a
Chris Lattner0b1c9a52010-03-17 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 Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]57
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]58<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]59main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greif355f81c2008-10-14 11:00:32 +0000[diff] [blame]60current one. To see the release notes for a specific release, please see the
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]61<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]62
63</div>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]64
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]65
Chris Lattneraa61f412009-10-13 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 Lattner06971182010-04-13 06:37:00 +0000[diff] [blame]71 ABCD, GEPSplitterPass
Chris Lattner89ea59d2010-01-16 21:25:13 +0000[diff] [blame]72 MSIL backend?
Chris Lattner10a3cc42010-03-17 06:41:58 +0000[diff] [blame]73 lib/Transforms/Utils/SSI.cpp -> ABCD depends on it.
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]74-->
75
76
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]77<!-- Features that need text if they're finished for 2.7:
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]78 combiner-aa?
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]79 strong phi elim
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]80 llvm.dbg.value: variable debug info for optimized code
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]81 loop dependence analysis
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]82 -->
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]83
Chris Lattnerc4d68542008-10-12 19:47:48 +0000[diff] [blame]84 <!-- for announcement email:
Chris Lattneraa61f412009-10-13 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 Lattner10a3cc42010-03-17 06:41:58 +0000[diff] [blame]90 Mention gcc plugin.
Chris Lattnerd02da042009-02-25 06:34:50 +0000[diff] [blame]91 -->
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]92
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]93<!-- *********************************************************************** -->
94<div class="doc_section">
95 <a name="subproj">Sub-project Status Update</a>
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]96</div>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]97<!-- *********************************************************************** -->
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]98
99<div class="doc_text">
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]100<p>
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]101The LLVM 2.7 distribution currently consists of code from the core LLVM
Chris Lattneraa61f412009-10-13 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 Wendlingf170d2e2009-03-02 04:28:57 +0000[diff] [blame]106</p>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]107
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]108</div>
109
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]110
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]111<!--=========================================================================-->
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]112<div class="doc_subsection">
Chris Lattner44c09cd2008-10-13 18:11:54 +0000[diff] [blame]113<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]114</div>
115
116<div class="doc_text">
117
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]118<p>The <a href="http://clang.llvm.org/">Clang project</a> is ...</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]119
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]120<p>In the LLVM 2.7 time-frame, the Clang team has made many improvements:</p>
Bill Wendlingef362462008-10-27 09:27:33 +0000[diff] [blame]121
Daniel Dunbarc11b40f2008-10-14 23:25:09 +0000[diff] [blame]122<ul>
Chris Lattnercecb9232010-04-22 17:25:00 +0000[diff] [blame]123<li>FIXME: C++! Include a link to cxx_compatibility.html Clang 2.7 can
124bootstrap???</li>
Daniel Dunbareb4bc7f2010-03-25 16:09:18 +0000[diff] [blame]125
Daniel Dunbareb4bc7f2010-03-25 16:09:18 +0000[diff] [blame]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>
Wesley Peck9bc5e8f2010-04-22 14:19:00 +0000[diff] [blame]131documentation for more details. The CIndex API also includes a preliminary
Daniel Dunbareb4bc7f2010-03-25 16:09:18 +0000[diff] [blame]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 Wendling87adbe42009-03-02 04:28:18 +0000[diff] [blame]137</ul>
Chris Lattner44c09cd2008-10-13 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
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]147<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a>
148 project is an effort to use static source code analysis techniques to
149 automatically find bugs in C and Objective-C programs (and hopefully <a
150 href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the
151 future</a>!). The tool is very good at finding bugs that occur on specific
152 paths through code, such as on error conditions.</p>
Chris Lattnerbcffa5a2008-10-14 00:52:49 +0000[diff] [blame]153
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]154<p>In the LLVM 2.7 time-frame, the analyzer core has made several major and
155 minor improvements, including better support for tracking the fields of
156 structures, initial support (not enabled by default yet) for doing
157 interprocedural (cross-function) analysis, and new checks have been added.
158</p>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]159
160</div>
161
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]162<!--=========================================================================-->
163<div class="doc_subsection">
Nicolas Geoffraye5ec9322008-10-14 19:23:04 +0000[diff] [blame]164<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]165</div>
166
167<div class="doc_text">
168<p>
Nicolas Geoffraye5ec9322008-10-14 19:23:04 +0000[diff] [blame]169The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]170a JVM and a CLI Virtual Machine (Microsoft .NET is an
171implementation of the CLI) using LLVM for static and just-in-time
172compilation.</p>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]173
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]174<p>
Chris Lattneref2e5732010-03-29 18:34:13 +0000[diff] [blame]175With the release of LLVM 2.7, VMKit has shifted to a great framework for writing
176virtual machines. VMKit now offers precise and efficient garbage collection with
177multi-threading support, thanks to the MMTk memory management toolkit, as well
178as just in time and ahead of time compilation with LLVM. The major changes in
179VMKit 0.27 are:</p>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]180
Nicolas Geoffraye5ec9322008-10-14 19:23:04 +0000[diff] [blame]181<ul>
182
Chris Lattneref2e5732010-03-29 18:34:13 +0000[diff] [blame]183<li>Garbage collection: VMKit now uses the MMTk toolkit for garbage collectors.
184 The first collector to be ported is the MarkSweep collector, which is precise,
185 and drastically improves the performance of VMKit.</li>
186<li>Line number information in the JVM: by using the debug metadata of LLVM, the
187 JVM now supports precise line number information, useful when printing a stack
188 trace.</li>
189<li>Interface calls in the JVM: we implemented a variant of the Interface Method
190 Table technique for interface calls in the JVM.
191</li>
Nicolas Geoffraye5ec9322008-10-14 19:23:04 +0000[diff] [blame]192
193</ul>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]194</div>
195
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]196
197<!--=========================================================================-->
198<div class="doc_subsection">
199<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
200</div>
201
202<div class="doc_text">
203<p>
204The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
205is a simple library that provides an implementation of the low-level
206target-specific hooks required by code generation and other runtime components.
207For example, when compiling for a 32-bit target, converting a double to a 64-bit
208unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
209function. The compiler-rt library provides highly optimized implementations of
210this and other low-level routines (some are 3x faster than the equivalent
211libgcc routines).</p>
212
213<p>
214All of the code in the compiler-rt project is available under the standard LLVM
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]215License, a "BSD-style" license. New in LLVM 2.7: compiler_rt now
216supports ARM targets.</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]217
218</div>
219
220<!--=========================================================================-->
221<div class="doc_subsection">
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]222<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]223</div>
224
225<div class="doc_text">
226<p>
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]227<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
228gcc-4.5. Unlike llvm-gcc, which makes many intrusive changes to the underlying
229gcc-4.2 code, dragonegg in theory does not require any gcc-4.5 modifications
230whatsoever (currently one small patch is needed). This is thanks to the new
231<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>, which
232makes it possible to modify the behaviour of gcc at runtime by loading a plugin,
233which is nothing more than a dynamic library which conforms to the gcc plugin
234interface. DragonEgg is a gcc plugin that causes the LLVM optimizers to be run
235instead of the gcc optimizers, and the LLVM code generators instead of the gcc
236code generators, just like llvm-gcc. To use it, you add
237"-fplugin=path/dragonegg.so" to the gcc-4.5 command line, and gcc-4.5 magically
238becomes llvm-gcc-4.5!
239</p>
240
241<p>
242DragonEgg is still a work in progress. Currently C works very well, while C++,
243Ada and Fortran work fairly well. All other languages either don't work at all,
244or only work poorly. For the moment only the x86-32 and x86-64 targets are
Duncan Sands4dd125e2010-04-20 19:40:58 +0000[diff] [blame]245supported, and only on linux and darwin (darwin needs an additional gcc patch).
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]246</p>
247
248<p>
Duncan Sandsfe291172010-04-21 13:51:48 +0000[diff] [blame]249DragonEgg is a new project which is seeing its first release with llvm-2.7.
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]250</p>
251
252</div>
253
254
255<!--=========================================================================-->
256<div class="doc_subsection">
257<a name="mc">llvm-mc: Machine Code Toolkit</a>
258</div>
259
260<div class="doc_text">
261<p>
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]262The LLVM Machine Code (aka MC) sub-project of LLVM was created to solve a number
263of problems in the realm of assembly, disassembly, object file format handling,
264and a number of other related areas that CPU instruction-set level tools work
265in. It is a sub-project of LLVM which provides it with a number of advantages
266over other compilers that do not have tightly integrated assembly-level tools.
267For a gentle introduction, please see the <a
268href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
269LLVM MC Project Blog Post</a>.
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]270</p>
271
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]272<p>2.7 includes major parts of the work required by the new MC Project. A few
273 targets have been refactored to support it, and work is underway to support a
274 native assembler in LLVM. This work is not complete in LLVM 2.7, but you has
275 made substantially more progress on LLVM mainline.</p>
276
277<p>One minor example of what MC can do is to transcode an AT&amp;T syntax
Gabor Greifd80517c2010-04-22 10:25:23 +0000[diff] [blame]278 X86 .s file into intel syntax. You can do this with something like:</p>
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]279<pre>
280 llvm-mc foo.s -output-asm-variant=1 -o foo-intel.s
281</pre>
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]282
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]283</div>
284
285
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]286<!-- *********************************************************************** -->
287<div class="doc_section">
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]288 <a name="externalproj">External Open Source Projects Using LLVM 2.7</a>
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]289</div>
290<!-- *********************************************************************** -->
291
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]292<div class="doc_text">
293
294<p>An exciting aspect of LLVM is that it is used as an enabling technology for
295 a lot of other language and tools projects. This section lists some of the
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]296 projects that have already been updated to work with LLVM 2.7.</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]297</div>
298
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]299<!--=========================================================================-->
300<div class="doc_subsection">
301<a name="pure">Pure</a>
302</div>
303
304<div class="doc_text">
305<p>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]306<a href="http://pure-lang.googlecode.com/">Pure</a>
307is an algebraic/functional programming language based on term rewriting.
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]308Programs are collections of equations which are used to evaluate expressions in
309a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]310lexical closures, a hygienic macro system (also based on term rewriting),
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]311built-in list and matrix support (including list and matrix comprehensions) and
312an easy-to-use C interface. The interpreter uses LLVM as a backend to
313 JIT-compile Pure programs to fast native code.</p>
314
Chris Lattner6aba4862010-03-17 17:25:49 +0000[diff] [blame]315<p>Pure versions 0.43 and later have been tested and are known to work with
316LLVM 2.7 (and continue to work with older LLVM releases >= 2.5).</p>
317
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]318</div>
319
Chris Lattnerfb23a962009-02-28 18:58:01 +0000[diff] [blame]320<!--=========================================================================-->
321<div class="doc_subsection">
322<a name="RoadsendPHP">Roadsend PHP</a>
323</div>
324
325<div class="doc_text">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]326<p>
327<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
Chris Lattner0c72d8f2009-03-02 19:07:24 +0000[diff] [blame]328source implementation of the PHP programming
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]329language that uses LLVM for its optimizer, JIT and static compiler. This is a
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]330reimplementation of an earlier project that is now based on LLVM.
Chris Lattner6aba4862010-03-17 17:25:49 +0000[diff] [blame]331</p>
Chris Lattnerfb23a962009-02-28 18:58:01 +0000[diff] [blame]332</div>
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]333
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]334<!--=========================================================================-->
335<div class="doc_subsection">
336<a name="UnladenSwallow">Unladen Swallow</a>
337</div>
338
339<div class="doc_text">
340<p>
341<a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
342branch of <a href="http://python.org/">Python</a> intended to be fully
343compatible and significantly faster. It uses LLVM's optimization passes and JIT
Chris Lattner5b59a732010-03-18 06:52:15 +0000[diff] [blame]344compiler.
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]345</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]346</div>
347
348<!--=========================================================================-->
349<div class="doc_subsection">
Chris Lattnerb4a02792010-03-29 17:50:39 +0000[diff] [blame]350<a name="tce">TTA-based Codesign Environment (TCE)</a>
351</div>
352
353<div class="doc_text">
354<p>
355<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing
356application-specific processors (ASP) based on the Transport triggered
357architecture (TTA). The toolset provides a complete co-design flow from C/C++
358programs down to synthesizable VHDL and parallel program binaries. Processor
359customization points include the register files, function units, supported
360operations, and the interconnection network.</p>
361
362<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target
363independent optimizations and also for parts of code generation. It generates
364new LLVM-based code generators "on the fly" for the designed TTA processors and
365loads them in to the compiler backend as runtime libraries to avoid per-target
366recompilation of larger parts of the compiler chain.</p>
367
368</div>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]369
John Criswell9003e0f2010-04-06 14:52:14 +0000[diff] [blame]370<!--=========================================================================-->
371<div class="doc_subsection">
372<a name="safecode">SAFECode Compiler</a>
373</div>
374
375<div class="doc_text">
376<p>
377<a href="http://safecode.cs.illinois.edu">SAFECode</a> is a memory safe C
378compiler built using LLVM. It takes standard, unannotated C code, analyzes the
379code to ensure that memory accesses and array indexing operations are safe, and
380instruments the code with run-time checks when safety cannot be proven
381statically.
382</p>
383</div>
384
Chris Lattnerad280412010-04-22 17:28:36 +0000[diff] [blame^]385<!--=========================================================================-->
386<div class="doc_subsection">
387<a name="icedtea">IcedTea Java Virtual Machine Implementation</a>
388</div>
John Criswell9003e0f2010-04-06 14:52:14 +0000[diff] [blame]389
Chris Lattnerad280412010-04-22 17:28:36 +0000[diff] [blame^]390<div class="doc_text">
391<p>
392<a href="http://icedtea.classpath.org/wiki/Main_Page">IcedTea</a> provides a
393harness to build OpenJDK using only free software build tools and to provide
394replacements for the not-yet free parts of OpenJDK. One of the extensions that
395IcedTea provides is a new JIT compiler named <a
396href="http://icedtea.classpath.org/wiki/ZeroSharkFaq">Shark</a> which uses LLVM
397to provide native code generation without introducing processor-dependent
398code.
399</p>
400<p>Icedtea6 1.8 and later have been tested and are known to work with
401LLVM 2.7 (and continue to work with older LLVM releases >= 2.6 as well).
402</p>
403</div>
404
405<!--=========================================================================-->
406<div class="doc_subsection">
407<a name="llvm-lua">LLVM-Lua</a>
408</div>
409
410<div class="doc_text">
411<p>
412<a href="http://code.google.com/p/llvm-lua/">LLVM-Lua</a> uses LLVM
413 to add JIT and static compiling support to the Lua VM. Lua
414bytecode is analyzed to remove type checks, then LLVM is used to compile the
415bytecode down to machine code.
416</p>
417<p>LLVM-Lua 1.2.0 have been tested and is known to work with LLVM 2.7.
418</p>
419</div>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]420<!-- *********************************************************************** -->
421<div class="doc_section">
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]422 <a name="whatsnew">What's New in LLVM 2.7?</a>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]423</div>
424<!-- *********************************************************************** -->
425
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]426<div class="doc_text">
427
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]428<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]429minor improvements. Some of the major improvements and new features are listed
430in this section.
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]431</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]432
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]433</div>
434
435<!--=========================================================================-->
436<div class="doc_subsection">
437<a name="orgchanges">LLVM Community Changes</a>
438</div>
439
440<div class="doc_text">
441
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]442<p>In addition to changes to the code, between LLVM 2.6 and 2.7, a number of
443organization changes have happened:
444</p>
445
446<ul>
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]447<li>LLVM has a new <a href="http://llvm.org/Logo.html">official logo</a>!</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]448
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]449<li>Ted Kremenek and Doug Gregor have stepped forward as <a
450 href="http://llvm.org/docs/DeveloperPolicy.html#owners">Code Owners</a> of the
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]451 Clang static analyzer and the Clang frontend, respectively.</li>
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]452
453<li>LLVM now has an <a href="http://blog.llvm.org">official Blog</a> at
454 <a href="http://blog.llvm.org">http://blog.llvm.org</a>. This is a great way
455 to learn about new LLVM-related features as they are implemented. Several
456 features in this release are already explained on the blog.</li>
457
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]458<li>The LLVM web pages are now checked into the SVN server, in the "www",
459 "www-pubs" and "www-releases" SVN modules. Previously they were hidden in a
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]460 largely inaccessible old CVS server.</li>
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]461
462<li><a href="http://llvm.org">llvm.org</a> is now hosted on a new (and much
463 faster) server. It is still graciously hosted at the University of Illinois
464 of Urbana Champaign.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]465</ul>
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]466</div>
467
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]468<!--=========================================================================-->
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]469<div class="doc_subsection">
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]470<a name="majorfeatures">Major New Features</a>
471</div>
472
473<div class="doc_text">
474
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]475<p>LLVM 2.7 includes several major new capabilities:</p>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]476
477<ul>
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]478<li>2.7 includes initial support for the <a
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]479 href="http://en.wikipedia.org/wiki/MicroBlaze">MicroBlaze</a> target.
480 MicroBlaze is a soft processor core designed for Xilinx FPGAs.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]481
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]482<li>2.7 includes a new LLVM IR "extensible metadata" feature. This feature
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]483 supports many different use cases, including allowing front-end authors to
484 encode source level information into LLVM IR, which is consumed by later
485 language-specific passes. This is a great way to do high-level optimizations
486 like devirtualization, type-based alias analysis, etc. See the <a
487 href="http://blog.llvm.org/2010/04/extensible-metadata-in-llvm-ir.html">
488 Extensible Metadata Blog Post</a> for more information.</li>
489
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]490<li>2.7 encodes <a href="SourceLevelDebugging.html">debug information</a>
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]491in a completely new way, built on extensible metadata. The new implementation
492is much more memory efficient and paves the way for improvements to optimized
493code debugging experience.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]494
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]495<li>2.7 now directly supports taking the address of a label and doing an
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]496 indirect branch through a pointer. This is particularly useful for
497 interpreter loops, and is used to implement the GCC "address of label"
498 extension. For more information, see the <a
499href="http://blog.llvm.org/2010/01/address-of-label-and-indirect-branches.html">
500Address of Label and Indirect Branches in LLVM IR Blog Post</a>.
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]501
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]502<li>2.7 is the first release to start supporting APIs for assembling and
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]503 disassembling target machine code. These APIs are useful for a variety of
504 low level clients, and are surfaced in the new "enhanced disassembly" API.
505 For more information see the <a
506 href="http://blog.llvm.org/2010/01/x86-disassembler.html">The X86
507 Disassembler Blog Post</a> for more information.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]508
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]509<li>2.7 includes major parts of the work required by the new MC Project,
510 see the <a href="#mc">MC update above</a> for more information.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]511
Chris Lattner458e79f2008-02-10 08:18:42 +0000[diff] [blame]512</ul>
Chris Lattner10a3cc42010-03-17 06:41:58 +0000[diff] [blame]513
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]514</div>
515
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]516<!--=========================================================================-->
517<div class="doc_subsection">
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]518<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]519</div>
520
521<div class="doc_text">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]522<p>LLVM IR has several new features for better support of new targets and that
523expose new optimization opportunities:</p>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]524
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]525<ul>
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]526<li>LLVM IR now supports a 16-bit "half float" data type through <a
527 href="LangRef.html#int_fp16">two new intrinsics</a> and APFloat support.</li>
528<li>LLVM IR supports two new <a href="LangRef.html#fnattrs">function
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]529 attributes</a>: inlinehint and alignstack(n). The former is a hint to the
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]530 optimizer that a function was declared 'inline' and thus the inliner should
531 weight it higher when considering inlining it. The later
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]532 indicates to the code generator that the function diverges from the platform
533 ABI on stack alignment.</li>
534<li>The new <a href="LangRef.html#int_objectsize">llvm.objectsize</a> intrinsic
535 allows the optimizer to infer the sizes of memory objects in some cases.
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]536 This intrinsic is used to implement the GCC <tt>__builtin_object_size</tt>
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]537 extension.</li>
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]538<li>LLVM IR now supports marking load and store instructions with <a
539 href="LangRef.html#i_load">"non-temporal" hints</a> (building on the new
540 metadata feature). This hint encourages the code
541 generator to generate non-temporal accesses when possible, which are useful
542 for code that is carefully managing cache behavior. Currently, only the
543 X86 backend provides target support for this feature.</li>
544
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]545<li>LLVM 2.7 has pre-alpha support for <a
Gabor Greif862b3532010-04-22 10:11:24 +0000[diff] [blame]546 href="LangRef.html#t_union">unions in LLVM IR</a>.
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]547 Unfortunately, this support is not really usable in 2.7, so if you're
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]548 interested in pushing it forward, please help contribute to LLVM mainline.</li>
Gabor Greif27b166352010-04-22 10:21:43 +0000[diff] [blame]549
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]550</ul>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]551
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]552</div>
553
554<!--=========================================================================-->
555<div class="doc_subsection">
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]556<a name="optimizer">Optimizer Improvements</a>
557</div>
558
559<div class="doc_text">
560
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]561<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattner25879d72008-10-13 21:50:36 +0000[diff] [blame]562release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]563
564<ul>
565
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]566<li>The inliner reuses now merges arrays stack objects in different callees when
567 inlining multiple call sites into one function. This reduces the stack size
568 of the resultant function.</li>
569<li>The -basicaa alias analysis pass (which is the default) has been improved to
570 be less dependent on "type safe" pointers. It can now look through bitcasts
571 and other constructs more aggressively, allowing better load/store
572 optimization.</li>
573<li>The load elimination optimization in the GVN Pass [<a
574href="http://blog.llvm.org/2009/12/introduction-to-load-elimination-in-gvn.html">intro
575 blog post</a>] has been substantially improved to be more aggressive about
576 partial redundancy elimination and do more aggressive phi translation. Please
577 see the <a
578 href="http://blog.llvm.org/2009/12/advanced-topics-in-redundant-load.html">
579 Advanced Topics in Redundant Load Elimination with a Focus on PHI Translation
580 Blog Post</a> for more details.</li>
581<li>The module <a href="LangRef.html#datalayout">target data string</a> now
Wesley Peckc8459162010-04-22 13:28:34 +0000[diff] [blame]582 includes a notion of 'native' integer data types for the target. This
583 helps mid-level optimizations avoid promoting complex sequences of
584 operations to data types that are not natively supported (e.g. converting
585 i32 operations to i64 on 32-bit chips).</li>
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]586<li>The mid-level optimizer is now conservative when operating on a module with
587 no target data. Previously, it would default to SparcV9 settings, which is
588 not what most people expected.</li>
Chris Lattnera668b452010-04-21 06:42:24 +0000[diff] [blame]589<li>Jump threading is now much more aggressive at simplifying correlated
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]590 conditionals and threading blocks with otherwise complex logic. It has
591 subsumed the old "Conditional Propagation" pass, and -condprop has been
592 removed from LLVM 2.7.</li>
593<li>The -instcombine pass has been refactored from being one huge file to being
594 a library of its own. Internally, it uses a customized IRBuilder to clean
595 it up and simplify it.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]596
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]597<li>The optimal edge profiling pass is reliable and much more complete than in
598 2.6. It can be used with the llvm-prof tool but isn't wired up to the
599 llvm-gcc and clang command line options yet.</li>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]600
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]601<li>A new experimental alias analysis implementation, -scev-aa, has been added.
602 It uses LLVM's Scalar Evolution implementation to do symbolic analysis of
603 pointer offset expressions to disambiguate pointers. It can catch a few
604 cases that basicaa cannot, particularly in complex loop nests.</li>
Chris Lattnera668b452010-04-21 06:42:24 +0000[diff] [blame]605
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]606<li>The default pass ordering has been tweaked for improved optimization
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]607 effectiveness.</li>
Chris Lattnera668b452010-04-21 06:42:24 +0000[diff] [blame]608
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]609</ul>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]610
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]611</div>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]612
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]613
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]614<!--=========================================================================-->
615<div class="doc_subsection">
616<a name="executionengine">Interpreter and JIT Improvements</a>
617</div>
Chris Lattner25879d72008-10-13 21:50:36 +0000[diff] [blame]618
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]619<div class="doc_text">
620
621<ul>
Wesley Peckba1ad202010-04-22 13:36:27 +0000[diff] [blame]622<li>The JIT now supports generating debug information and is compatible with
623the new GDB 7.0 (and later) interfaces for registering dynamically generated
624debug info.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]625
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]626<li>The JIT now <a href="http://llvm.org/PR5184">defaults
Jeffrey Yasskin9fb8ce82010-01-29 19:10:38 +0000[diff] [blame]627to compiling eagerly</a> to avoid a race condition in the lazy JIT.
628Clients that still want the lazy JIT can switch it on by calling
629<tt>ExecutionEngine::DisableLazyCompilation(false)</tt>.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]630
Jeffrey Yasskine0913882010-02-11 01:07:39 +0000[diff] [blame]631<li>It is now possible to create more than one JIT instance in the same process.
632These JITs can generate machine code in parallel,
633although <a href="http://llvm.org/docs/ProgrammersManual.html#jitthreading">you
634still have to obey the other threading restrictions</a>.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]635
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]636</ul>
637
638</div>
639
640<!--=========================================================================-->
641<div class="doc_subsection">
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]642<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]643</div>
644
645<div class="doc_text">
646
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]647<p>We have put a significant amount of work into the code generator
648infrastructure, which allows us to implement more aggressive algorithms and make
649it run faster:</p>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]650
651<ul>
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]652<li>The 'llc -asm-verbose' option (which is now the default) has been enhanced
653 to emit many useful comments to .s files indicating information about spill
654 slots and loop nest structure. This should make it much easier to read and
655 understand assembly files. This is wired up in llvm-gcc and clang to
656 the <tt>-fverbose-asm</tt> option.</li>
657
658<li>New LSR with "full strength reduction" mode. FIXME: Description?</li>
659
660<li>A new codegen level Common Subexpression Elimination pass (MachineCSE)
661 is available and enabled by default. It catches redundancies exposed by
662 lowering.</li>
663<li>A new pre-register-allocation tail duplication pass is available and enabled
664 by default, it can substantially improve branch prediction quality in some
665 cases.</li>
666<li>A new sign and zero extension optimization pass (OptimizeExtsPass)
667 is available and enabled by default. This pass can takes advantage
668 architecture features like x86-64 implicit zero extension behavior and
669 sub-registers.</li>
670<li>The code generator now supports a mode where it attempts to preserve the
671 order of instructions in the input code. This is important for source that
672 is hand scheduled and extremely sensitive to scheduling. It is compatible
673 with the GCC <tt>-fno-schedule-insns</tt> option.</li>
674<li>The target-independent code generator now supports generating code with
675 arbitrary numbers of result values. Returning more values than was
676 previously supported is handled by returning through a hidden pointer. In
677 2.7, only the X86 and XCore targets have adopted support for this
678 though.</li>
679<li>The code generator now supports generating code that follows the
680 <a href="LangRef.html#callingconv">Glasgow Haskell Compiler Calling
681 Convention</a> and ABI.</li>
682<li>The "<a href="CodeGenerator.html#selectiondag_select">DAG instruction
683 selection</a>" phase of the code generator has been largely rewritten for
684 2.7. Previously, tblgen spit out tons of C++ code which was compiled and
685 linked into the target to do the pattern matching, now it emits a much
686 smaller table which is read by the target-independent code. The primary
687 advantages of this approach is that the size and compile time of various
688 targets is much improved. The X86 code generator shrunk by 1.5MB of code,
689 for example.</li>
690<li>Almost the entire code generator has switched to emitting code through the
691 MC interfaces instead of printing textually to the .s file. This led to a
692 number of cleanups and speedups. In 2.7, debug an exception handling
693 information does not go through MC yet.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]694</ul>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]695</div>
696
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]697<!--=========================================================================-->
698<div class="doc_subsection">
699<a name="x86">X86-32 and X86-64 Target Improvements</a>
700</div>
701
702<div class="doc_text">
703<p>New features of the X86 target include:
704</p>
705
706<ul>
Chris Lattnera668b452010-04-21 06:42:24 +0000[diff] [blame]707<li>The X86 backend now optimizes tails calls much more aggressively for
708 functions that use the standard C calling convention.</li>
709<li>The X86 backend now models scalar SSE registers as subregs of the SSE vector
710 registers, making the code generator more aggressive in cases where scalars
711 and vector types are mixed.</li>
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]712
Chris Lattnera668b452010-04-21 06:42:24 +0000[diff] [blame]713<li>PostRA scheduler for X86? FIXME: is this on by default in 2.7?</li>
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]714
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]715</ul>
716
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]717</div>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]718
719<!--=========================================================================-->
720<div class="doc_subsection">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]721<a name="ARM">ARM Target Improvements</a>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]722</div>
723
724<div class="doc_text">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]725<p>New features of the ARM target include:
726</p>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]727
728<ul>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]729
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]730<li>The ARM backend now generates instructions in unified assembly syntax.</li>
731
732<li>llvm-gcc now has complete support for the ARM v7 NEON instruction set. This
733 support differs slightly from the GCC implementation. Please see the
734 <a
735href="http://blog.llvm.org/2010/04/arm-advanced-simd-neon-intrinsics-and.html">
736 ARM Advanced SIMD (NEON) Intrinsics and Types in LLVM Blog Post</a> for
737 helpful information if migrating code from GCC to LLVM-GCC.</li>
738
Wesley Peck16144fb2010-04-22 13:43:14 +0000[diff] [blame]739<li>The ARM and Thumb code generators now use register scavenging for stack
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]740 object address materialization.(FIXME: WHAT BENEFIT DOES THIS PROVIDE?)</li>
741
Wesley Peck16144fb2010-04-22 13:43:14 +0000[diff] [blame]742<li>The ARM backend now has good support for ARMv4 targets and has been tested
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]743 on StrongARM hardware. Previously, LLVM only supported ARMv4T and
744 newer chips.</li>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]745</ul>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]746
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]747
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]748</div>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]749
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]750<!--=========================================================================-->
751<div class="doc_subsection">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]752<a name="newapis">New Useful APIs</a>
753</div>
754
755<div class="doc_text">
756
757<p>This release includes a number of new APIs that are used internally, which
758 may also be useful for external clients.
759</p>
760
761<ul>
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]762<li>The optimizer uses the new CodeMetrics class to measure the size of code.
763 Various passes that use thing (like the inliner, loop unswitcher, etc) all
764 use this to make more accurate estimates of the code size impact of various
765 optimizations.</li>
766<li>A new <a href="http://llvm.org/doxygen/InstructionSimplify_8h-source.html">
Wesley Peck3edc1682010-04-22 13:50:46 +0000[diff] [blame]767 llvm/Analysis/InstructionSimplify.h</a> interface is available for doing
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]768 symbolic simplification of instructions (e.g. <tt>a+0</tt> -&gt; <tt>a</tt>)
769 without requiring the instruction to exist. This centralizes a lot of
770 ad-hoc symbolic manipulation code scattered in various passes.</li>
771<li>The optimizer now uses a new <a
772 href="http://llvm.org/doxygen/SSAUpdater_8h-source.html">SSAUpdater</a>
773 class which efficiently supports
774 doing unstructured SSA update operations. This centralized a bunch of code
Wesley Peck3edc1682010-04-22 13:50:46 +0000[diff] [blame]775 scattered throughout various passes (e.g. jump threading, lcssa,
776 loop rotate, etc) for doing this sort of thing. The code generator has a
777 similar <a href="http://llvm.org/doxygen/MachineSSAUpdater_8h-source.html">
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]778 MachineSSAUpdater</a> class.</li>
779<li>The <a href="http://llvm.org/doxygen/Regex_8h-source.html">
780 llvm/Support/Regex.h</a> header exposes a platform independent regular
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]781 expression API. Building on this, the <a
782 href="TestingGuide.html#FileCheck">FileCheck</a> utility now supports
783 regular exressions.</li>
784<li>raw_ostream now supports a circular "debug stream" accessed with "dbgs()".
785 By default, this stream works the same way as "errs()", but if you pass
786 <tt>-debug-buffer-size=1000</tt> to opt, the debug stream is capped to a
787 fixed sized circular buffer and the output is printed at the end of the
788 program's execution. This is helpful if you have a long lived compiler
789 process and you're interested in seeing snapshots in time.</li>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]790</ul>
791
792
793</div>
794
795<!--=========================================================================-->
796<div class="doc_subsection">
797<a name="otherimprovements">Other Improvements and New Features</a>
798</div>
799
800<div class="doc_text">
801<p>Other miscellaneous features include:</p>
802
803<ul>
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]804<li>You can now build LLVM as a big dynamic library (e.g. "libllvm2.7.so"). To
805 get this, configure LLVM with the --enable-shared option.</li>
806
Wesley Peckcad613d2010-04-22 13:53:54 +0000[diff] [blame]807<li>LLVM command line tools now overwrite their output by default. Previously,
808 they would only do this with -f. This makes them more convenient to use, and
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]809 behave more like standard unix tools.</li>
810
811<li>The opt and llc tools now autodetect whether their input is a .ll or .bc
812 file, and automatically do the right thing. This means you don't need to
813 explicitly use the llvm-as tool for most things.</li>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]814</ul>
815
816</div>
817
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]818
819<!--=========================================================================-->
820<div class="doc_subsection">
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]821<a name="changes">Major Changes and Removed Features</a>
822</div>
823
824<div class="doc_text">
825
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]826<p>If you're already an LLVM user or developer with out-of-tree changes based
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]827on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]828from the previous release.</p>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]829
830<ul>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]831
832<li>
833The Andersen's alias analysis ("anders-aa") pass, the Predicate Simplifier
834("predsimplify") pass, the LoopVR pass, the GVNPRE pass, and the random sampling
835profiling ("rsprofiling") passes have all been removed. They were not being
836actively maintained and had substantial problems. If you are interested in
837these components, you are welcome to ressurect them from SVN, fix the
838correctness problems, and resubmit them to mainline.</li>
839
840<li>LLVM now defaults to building most libraries with RTTI turned off, providing
841a code size reduction. Packagers who are interested in building LLVM to support
842plugins that require RTTI information should build with "make REQUIRE_RTTI=1"
843and should read the new <a href="Packaging.html">Advice on Packaging LLVM</a>
844document.</li>
845
Jeffrey Yasskin914050b2010-02-09 23:03:44 +0000[diff] [blame]846<li>The LLVM interpreter now defaults to <em>not</em> using <tt>libffi</tt> even
847if you have it installed. This makes it more likely that an LLVM built on one
848system will work when copied to a similar system. To use <tt>libffi</tt>,
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]849configure with <tt>--enable-libffi</tt>.</li>
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]850
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]851<li>Debug information uses a completely different representation, an LLVM 2.6
852.bc file should work with LLVM 2.7, but debug info won't come forward.</li>
853
854<li>The LLVM 2.6 (and earlier) "malloc" and "free" instructions got removed,
855 along with LowerAllocations pass. Now you should just use a call to the
856 malloc and free functions in libc. These calls are optimized as well as
857 the old instructions were.</li>
858</ul>
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]859
860<p>In addition, many APIs have changed in this release. Some of the major LLVM
861API changes are:</p>
862
863<ul>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]864<li>Just about everything has been converted to use raw_ostream instead of
865 std::ostream.</li>
866<li>llvm/ADT/iterator.h has been removed, just use &lt;iterator&gt;
867 instead.</li>
868<li>The Streams.h file and "DOUT" got removed, use "DEBUG(errs() &lt;&lt; ...);"
869 instead.</li>
Chris Lattnercecb9232010-04-22 17:25:00 +0000[diff] [blame]870<li>The TargetAsmInfo interface was renamed to MCAsmInfo.</li>
Jeffrey Yasskin4a8b1da2010-01-28 01:41:20 +0000[diff] [blame]871<li><tt>ModuleProvider</tt> has been <a
Gabor Greif27b166352010-04-22 10:21:43 +0000[diff] [blame]872href="http://llvm.org/viewvc/llvm-project?view=rev&amp;revision=94686">removed</a>
Jeffrey Yasskin4a8b1da2010-01-28 01:41:20 +0000[diff] [blame]873and its methods moved to <tt>Module</tt> and <tt>GlobalValue</tt>.
874Most clients can remove uses of <tt>ExistingModuleProvider</tt>,
875replace <tt>getBitcodeModuleProvider</tt> with
876<tt>getLazyBitcodeModule</tt>, and pass their <tt>Module</tt> to
877functions that used to accept <tt>ModuleProvider</tt>. Clients who
878wrote their own <tt>ModuleProvider</tt>s will need to derive from
879<tt>GVMaterializer</tt> instead and use
880<tt>Module::setMaterializer</tt> to attach it to a
881<tt>Module</tt>.</li>
882
883<li><tt>GhostLinkage</tt> has given up the ghost.
884<tt>GlobalValue</tt>s that have not yet been read from their backing
885storage have the same linkage they will have after being read in.
886Clients must replace calls to
887<tt>GlobalValue::hasNotBeenReadFromBitcode</tt> with
888<tt>GlobalValue::isMaterializable</tt>.</li>
Daniel Dunbar1e96fca2010-02-10 04:09:52 +0000[diff] [blame]889
Daniel Dunbar3e255da2010-02-14 01:47:19 +0000[diff] [blame]890<li>The <tt>llvm/Support/DataTypes.h</tt> header has moved
891to <tt>llvm/System/DataTypes.h</tt>.</li>
892
Duncan Sands80c430a2010-02-17 17:20:17 +0000[diff] [blame]893<li>The <tt>isInteger</tt>, <tt>isIntOrIntVector</tt>, <tt>isFloatingPoint</tt>,
894<tt>isFPOrFPVector</tt> and <tt>isFPOrFPVector</tt> methods have been renamed
895<tt>isIntegerTy</tt>, <tt>isIntOrIntVectorTy</tt>, <tt>isFloatingPointTy</tt>,
896<tt>isFPOrFPVectorTy</tt> and <tt>isFPOrFPVectorTy</tt> respectively.</li>
Chris Lattnercecb9232010-04-22 17:25:00 +0000[diff] [blame]897
898<li><tt>llvm::Instruction::clone()</tt> no longer takes argument.</li>
899<li><tt>raw_fd_ostream</tt>'s constructor now takes a flag argument, not individual
900 booleans (see <tt>include/llvm/Support/raw_ostream.h</tt> for details).</li>
901<li>Some header files have been renamed:
902<ul>
903 <li><tt>llvm/Support/AIXDataTypesFix.h</tt> to
904 <tt>llvm/System/AIXDataTypesFix.h</tt></li>
905 <li><tt>llvm/Support/DataTypes.h</tt> to <tt>llvm/System/DataTypes.h</tt></li>
906 <li><tt>llvm/Transforms/Utils/InlineCost.h</tt> to
907 <tt>llvm/Analysis/InlineCost.h</tt></li>
908 <li><tt>llvm/Support/Mangler.h</tt> to <tt>llvm/Target/Mangler.h</tt></li>
909 <li><tt>llvm/Analysis/Passes.h</tt> to <tt>llvm/CodeGen/Passes.h</tt></li>
910</ul></li>
Devang Pateldbf83832008-10-14 20:03:43 +0000[diff] [blame]911</ul>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]912
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]913</div>
914
915
916
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]917<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]918<div class="doc_section">
919 <a name="portability">Portability and Supported Platforms</a>
920</div>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]921<!-- *********************************************************************** -->
922
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]923<div class="doc_text">
924
John Criswell64307722004-12-08 20:35:47 +0000[diff] [blame]925<p>LLVM is known to work on the following platforms:</p>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]926
927<ul>
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]928<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]929 Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like
930 systems).</li>
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]931<li>PowerPC and X86-based Mac OS X systems, running 10.4 and above in 32-bit
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]932 and 64-bit modes.</li>
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]933<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]934<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
935 support is available for native builds with Visual C++).</li>
Chris Lattner51948622009-10-16 16:30:58 +0000[diff] [blame]936<li>Sun x86 and AMD64 machines running Solaris 10, OpenSolaris 0906.</li>
John Criswelld5234922005-05-13 20:28:15 +0000[diff] [blame]937<li>Alpha-based machines running Debian GNU/Linux.</li>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]938</ul>
939
Chris Lattner618a99f2008-06-05 06:57:39 +0000[diff] [blame]940<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekee3e557e2004-05-09 05:28:35 +0000[diff] [blame]941to the machine and operating system on which it is built. However, minor
942porting may be required to get LLVM to work on new platforms. We welcome your
943portability patches and reports of successful builds or error messages.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]944
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]945</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]946
947<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]948<div class="doc_section">
949 <a name="knownproblems">Known Problems</a>
950</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]951<!-- *********************************************************************** -->
952
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]953<div class="doc_text">
954
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]955<p>This section contains significant known problems with the LLVM system,
Chris Lattner2a092392008-11-10 05:40:34 +0000[diff] [blame]956listed by component. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]957href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]958there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]959
Chris Lattner6aba4862010-03-17 17:25:49 +0000[diff] [blame]960<ul>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]961<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
962using the stock GCC 3.x.x series 'out the box',
Chris Lattner6e41c792009-11-03 21:50:09 +0000[diff] [blame]963See: <a href="GettingStarted.html#brokengcc">Broken versions of GCC and other tools</a>.
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]964However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
965for x86/x86-64 has been made available from the third party AuroraUX Project
966that has been meticulously tested for bootstrapping LLVM &amp; Clang.</li>
967</ul>
968
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]969</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]970
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]971<!-- ======================================================================= -->
972<div class="doc_subsection">
973 <a name="experimental">Experimental features included with this release</a>
974</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]975
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]976<div class="doc_text">
977
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]978<p>The following components of this LLVM release are either untested, known to
979be broken or unreliable, or are in early development. These components should
980not be relied on, and bugs should not be filed against them, but they may be
981useful to some people. In particular, if you would like to work on one of these
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]982components, please contact us on the <a
983href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]984
985<ul>
Wesley Peck3aa84e52010-03-18 14:31:30 +0000[diff] [blame]986<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
987 backends are experimental.</li>
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]988<li><tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
Chris Lattner0b1c9a52010-03-17 04:41:49 +0000[diff] [blame]989 supported value for this option. The MachO writer is experimental, and
990 works much better in mainline SVN.</li>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]991</ul>
992
993</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]994
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]995<!-- ======================================================================= -->
996<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]997 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]998</div>
999
1000<div class="doc_text">
1001
1002<ul>
Anton Korobeynikov486c7d32008-06-08 10:24:13 +0000[diff] [blame]1003 <li>The X86 backend does not yet support
1004 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
1005 floating point stack</a>. It supports the 'f' and 't' constraints, but not
1006 'u'.</li>
Chris Lattnerb076b002008-06-08 21:19:07 +0000[diff] [blame]1007 <li>The X86 backend generates inefficient floating point code when configured
1008 to generate code for systems that don't have SSE2.</li>
Duncan Sands0bc15262008-06-08 19:38:43 +0000[diff] [blame]1009 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]1010 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]1011 runtime currently due to lack of support for the 'u' inline assembly
1012 constraint and for X87 floating point inline assembly.</li>
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]1013 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]1014 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]1015 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1016</ul>
1017
1018</div>
1019
1020<!-- ======================================================================= -->
1021<div class="doc_subsection">
1022 <a name="ppc-be">Known problems with the PowerPC back-end</a>
1023</div>
1024
1025<div class="doc_text">
1026
1027<ul>
Nicolas Geoffray77d99502007-05-15 09:21:28 +0000[diff] [blame]1028<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]1029compilation, and lacks support for debug information.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1030</ul>
1031
1032</div>
1033
1034<!-- ======================================================================= -->
1035<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]1036 <a name="arm-be">Known problems with the ARM back-end</a>
1037</div>
1038
1039<div class="doc_text">
1040
1041<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]1042<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands47fc0a22007-09-26 15:59:54 +0000[diff] [blame]1043processors, thumb programs can crash or produce wrong
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]1044results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]1045<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]1046</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]1047</ul>
1048
1049</div>
1050
1051<!-- ======================================================================= -->
1052<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1053 <a name="sparc-be">Known problems with the SPARC back-end</a>
1054</div>
1055
1056<div class="doc_text">
1057
1058<ul>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]1059<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1060 support the 64-bit SPARC ABI (-m64).</li>
1061</ul>
1062
1063</div>
1064
1065<!-- ======================================================================= -->
1066<div class="doc_subsection">
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]1067 <a name="mips-be">Known problems with the MIPS back-end</a>
1068</div>
1069
1070<div class="doc_text">
1071
1072<ul>
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]1073<li>64-bit MIPS targets are not supported yet.</li>
1074</ul>
1075
1076</div>
1077
1078<!-- ======================================================================= -->
1079<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1080 <a name="alpha-be">Known problems with the Alpha back-end</a>
1081</div>
1082
1083<div class="doc_text">
1084
1085<ul>
1086
1087<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
1088appropriate nops inserted to ensure restartability.</li>
1089
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]1090</ul>
1091</div>
1092
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1093<!-- ======================================================================= -->
1094<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]1095 <a name="c-be">Known problems with the C back-end</a>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1096</div>
1097
1098<div class="doc_text">
1099
1100<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]1101<li><a href="http://llvm.org/PR802">The C backend has only basic support for
1102 inline assembly code</a>.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000[diff] [blame]1103<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
1104 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif75b2f762009-03-02 12:02:51 +0000[diff] [blame]1105 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandse09506a2008-02-10 13:40:55 +0000[diff] [blame]1106<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands3aa36732009-02-25 11:51:54 +0000[diff] [blame]1107<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1108</ul>
1109
1110</div>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]1111
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1112
1113<!-- ======================================================================= -->
1114<div class="doc_subsection">
Chris Lattner0b1c9a52010-03-17 04:41:49 +0000[diff] [blame]1115 <a name="c-fe">Known problems with the llvm-gcc C and C++ front-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1116</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000[diff] [blame]1117
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1118<div class="doc_text">
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]1119
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]1120<p>The only major language feature of GCC not supported by llvm-gcc is
1121 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
1122 are only supported on some targets. For example, trampolines are only
Duncan Sands56448462008-06-08 20:18:35 +0000[diff] [blame]1123 supported on some targets (these are used when you take the address of a
1124 nested function).</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1125
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1126</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1127
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1128<!-- ======================================================================= -->
1129<div class="doc_subsection">
Chris Lattner7292fb12008-10-30 03:58:13 +0000[diff] [blame]1130 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
1131</div>
1132
1133<div class="doc_text">
Gabor Greife5f9d672008-11-04 21:50:59 +0000[diff] [blame]1134<ul>
Chris Lattner7292fb12008-10-30 03:58:13 +0000[diff] [blame]1135<li>Fortran support generally works, but there are still several unresolved bugs
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]1136 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
1137 tools/gfortran component for details.</li>
Gabor Greife5f9d672008-11-04 21:50:59 +0000[diff] [blame]1138</ul>
Chris Lattner7292fb12008-10-30 03:58:13 +0000[diff] [blame]1139</div>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1140
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1141<!-- ======================================================================= -->
1142<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]1143 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1144</div>
1145
1146<div class="doc_text">
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]1147The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
1148technology, and problems should be expected.
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1149<ul>
Duncan Sands56448462008-06-08 20:18:35 +0000[diff] [blame]1150<li>The Ada front-end currently only builds on X86-32. This is mainly due
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]1151to lack of trampoline support (pointers to nested functions) on other platforms.
1152However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1153which does support trampolines.</li>
1154<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
Duncan Sandsd34bf762009-02-25 11:59:06 +0000[diff] [blame]1155This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
1156exception handling, which is used internally by the compiler.
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]1157Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
Duncan Sandsaef747f2008-10-13 17:27:23 +0000[diff] [blame]1158<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
1159and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sandsd34bf762009-02-25 11:59:06 +0000[diff] [blame]1160(c380004 also fails with gcc-4.2 mainline).
1161If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
1162causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sands2dbb00e2009-03-02 16:35:57 +0000[diff] [blame]1163<li>Some GCC specific Ada tests continue to crash the compiler.</li>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]1164<li>The <tt>-E</tt> binder option (exception backtraces)
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1165<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]1166crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1167<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
1168or finish at a non-byte offset</a> in a record. Workaround: do not pack records
1169or use representation clauses that result in a field of a non-discrete type
1170starting or finishing in the middle of a byte.</li>
Chris Lattnerb076b002008-06-08 21:19:07 +0000[diff] [blame]1171<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
1172'main' as generated by the Ada binder to be invalid</a>.
1173Workaround: hand edit the file to use pointers for <tt>argv</tt> and
1174<tt>envp</tt> rather than integers.</li>
1175<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
1176ignored</a>.</li>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1177</ul>
1178</div>
1179
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1180<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1181<div class="doc_section">
1182 <a name="additionalinfo">Additional Information</a>
1183</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1184<!-- *********************************************************************** -->
1185
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1186<div class="doc_text">
1187
Chris Lattnercb5596d2005-05-16 17:13:10 +0000[diff] [blame]1188<p>A wide variety of additional information is available on the <a
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]1189href="http://llvm.org">LLVM web page</a>, in particular in the <a
1190href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]1191contains versions of the API documentation which is up-to-date with the
1192Subversion version of the source code.
Misha Brukman96158092005-03-30 19:14:24 +0000[diff] [blame]1193You can access versions of these documents specific to this release by going
1194into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1195
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1196<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]1197us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]1198lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1199
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1200</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1201
1202<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1203
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1204<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1205<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000[diff] [blame]1206 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]1207 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1208 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]1209 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1210
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]1211 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1212 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1213</address>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1214
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1215</body>
1216</html>