Gitiles
Code Review Sign In
gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 28f735f29f65d9d091aa92c6e4cd97d79ac8e6fb / . / docs / ReleaseNotes.html
blob: ad65a7a131e8e38b5fec761f7d7890879e31e7e4 [file] [log] [blame]
Dan Gohmanf17a25c2007-07-18 16:29:46 +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>
5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
6 <link rel="stylesheet" href="llvm.css" type="text/css">
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]7 <title>LLVM 2.7 Release Notes</title>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]8</head>
9<body>
10
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]11<div class="doc_title">LLVM 2.7 Release Notes</div>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]12
Chris Lattnere5236102010-03-17 04:02:39 +0000[diff] [blame]13<img align=right src="http://llvm.org/img/DragonSmall.png"
Gabor Greif92d28ea2010-04-22 10:21:43 +0000[diff] [blame]14 width="136" height="136" alt="LLVM Dragon Logo">
Chris Lattnere5236102010-03-17 04:02:39 +0000[diff] [blame]15
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]16<ol>
17 <li><a href="#intro">Introduction</a></li>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]18 <li><a href="#subproj">Sub-project Status Update</a></li>
Jeffrey Yasskin8ee1b0a2010-01-28 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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]21 <li><a href="GettingStarted.html">Installation Instructions</a></li>
22 <li><a href="#portability">Portability and Supported Platforms</a></li>
Dan Gohman0de549c2008-10-14 16:23:02 +0000[diff] [blame]23 <li><a href="#knownproblems">Known Problems</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]24 <li><a href="#additionalinfo">Additional Information</a></li>
25</ol>
26
27<div class="doc_author">
Dan Gohman0de549c2008-10-14 16:23:02 +0000[diff] [blame]28 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]29</div>
30
Chris Lattner6ba1be32010-04-13 06:37:00 +0000[diff] [blame]31<!--
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]32<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.8
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]33release.<br>
34You may prefer the
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]35<a href="http://llvm.org/releases/2.6/docs/ReleaseNotes.html">LLVM 2.7
Chris Lattner6ba1be32010-04-13 06:37:00 +0000[diff] [blame]36Release Notes</a>.</h1>-->
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]37
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]38<!-- *********************************************************************** -->
39<div class="doc_section">
40 <a name="intro">Introduction</a>
41</div>
42<!-- *********************************************************************** -->
43
44<div class="doc_text">
45
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]46<p>This document contains the release notes for the LLVM Compiler
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]47Infrastructure, release 2.7. Here we describe the status of LLVM, including
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]48major improvements from the previous release and significant known problems.
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame]49All LLVM releases may be downloaded from the <a
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]50href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]51
52<p>For more information about LLVM, including information about the latest
53release, please check out the <a href="http://llvm.org/">main LLVM
54web site</a>. If you have questions or comments, the <a
Chris Lattner58b1d0f2010-03-17 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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]57
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]58<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]59main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greif7c65c4f2008-10-14 11:00:32 +0000[diff] [blame]60current one. To see the release notes for a specific release, please see the
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]61<a href="http://llvm.org/releases/">releases page</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]62
63</div>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]64
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]65
Chris Lattner0b6ea7a2009-10-13 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 Lattner6ba1be32010-04-13 06:37:00 +0000[diff] [blame]71 ABCD, GEPSplitterPass
Chris Lattner2bd5e652010-01-16 21:25:13 +0000[diff] [blame]72 MSIL backend?
Chris Lattner2b656342010-03-17 06:41:58 +0000[diff] [blame]73 lib/Transforms/Utils/SSI.cpp -> ABCD depends on it.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]74-->
75
76
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]77<!-- Features that need text if they're finished for 2.7:
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]78 combiner-aa?
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]79 strong phi elim
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]80 llvm.dbg.value: variable debug info for optimized code
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]81 loop dependence analysis
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]82 -->
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]83
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]84 <!-- for announcement email:
Chris Lattner0b6ea7a2009-10-13 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 Lattner2b656342010-03-17 06:41:58 +0000[diff] [blame]90 Mention gcc plugin.
Chris Lattnera53f4972009-02-25 06:34:50 +0000[diff] [blame]91 -->
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]92
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]93<!-- *********************************************************************** -->
94<div class="doc_section">
95 <a name="subproj">Sub-project Status Update</a>
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]96</div>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]97<!-- *********************************************************************** -->
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]98
99<div class="doc_text">
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]100<p>
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]101The LLVM 2.7 distribution currently consists of code from the core LLVM
Chris Lattner0b6ea7a2009-10-13 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 Wendlingdde41b82009-03-02 04:28:57 +0000[diff] [blame]106</p>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]107
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]108</div>
109
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]110
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]111<!--=========================================================================-->
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]112<div class="doc_subsection">
Chris Lattnera3c683b2008-10-13 18:11:54 +0000[diff] [blame]113<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]114</div>
115
116<div class="doc_text">
117
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]118<p>The <a href="http://clang.llvm.org/">Clang project</a> is ...</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]119
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]120<p>In the LLVM 2.7 time-frame, the Clang team has made many improvements:</p>
Bill Wendling385b0d32008-10-27 09:27:33 +0000[diff] [blame]121
Daniel Dunbarf3e35782008-10-14 23:25:09 +0000[diff] [blame]122<ul>
Daniel Dunbar29f1e722010-03-25 16:09:18 +0000[diff] [blame]123<li>FIXME: C++! Include a link to cxx_compatibility.html</li>
124
Daniel Dunbar29f1e722010-03-25 16:09:18 +0000[diff] [blame]125<li>CIndex API and Python bindings: Clang now includes a C API as part of the
126CIndex library. Although we make make some changes to the API in the future, it
127is intended to be stable and has been designed for use by external projects. See
128the Clang
129doxygen <a href="http://clang.llvm.org/doxygen/group__CINDEX.html">CIndex</a>
Wesley Peck43e93692010-04-22 14:19:00 +0000[diff] [blame]130documentation for more details. The CIndex API also includes a preliminary
Daniel Dunbar29f1e722010-03-25 16:09:18 +0000[diff] [blame]131set of Python bindings.</li>
132
133<li>ARM Support: Clang now has ABI support for both the Darwin and Linux ARM
134ABIs. Coupled with many improvements to the LLVM ARM backend, Clang is now
135suitable for use as a a beta quality ARM compiler.</li>
Bill Wendlinga8fb81d2009-03-02 04:28:18 +0000[diff] [blame]136</ul>
Chris Lattnera3c683b2008-10-13 18:11:54 +0000[diff] [blame]137</div>
138
139<!--=========================================================================-->
140<div class="doc_subsection">
141<a name="clangsa">Clang Static Analyzer</a>
142</div>
143
144<div class="doc_text">
145
Chris Lattnerfa63e262010-04-22 06:38:11 +0000[diff] [blame]146<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a>
147 project is an effort to use static source code analysis techniques to
148 automatically find bugs in C and Objective-C programs (and hopefully <a
149 href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the
150 future</a>!). The tool is very good at finding bugs that occur on specific
151 paths through code, such as on error conditions.</p>
Chris Lattnerc2d84672008-10-14 00:52:49 +0000[diff] [blame]152
Chris Lattnerfa63e262010-04-22 06:38:11 +0000[diff] [blame]153<p>In the LLVM 2.7 time-frame, the analyzer core has made several major and
154 minor improvements, including better support for tracking the fields of
155 structures, initial support (not enabled by default yet) for doing
156 interprocedural (cross-function) analysis, and new checks have been added.
157</p>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]158
159</div>
160
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]161<!--=========================================================================-->
162<div class="doc_subsection">
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000[diff] [blame]163<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]164</div>
165
166<div class="doc_text">
167<p>
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000[diff] [blame]168The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]169a JVM and a CLI Virtual Machine (Microsoft .NET is an
170implementation of the CLI) using LLVM for static and just-in-time
171compilation.</p>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]172
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]173<p>
Chris Lattnerd5b62522010-03-29 18:34:13 +0000[diff] [blame]174With the release of LLVM 2.7, VMKit has shifted to a great framework for writing
175virtual machines. VMKit now offers precise and efficient garbage collection with
176multi-threading support, thanks to the MMTk memory management toolkit, as well
177as just in time and ahead of time compilation with LLVM. The major changes in
178VMKit 0.27 are:</p>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]179
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000[diff] [blame]180<ul>
181
Chris Lattnerd5b62522010-03-29 18:34:13 +0000[diff] [blame]182<li>Garbage collection: VMKit now uses the MMTk toolkit for garbage collectors.
183 The first collector to be ported is the MarkSweep collector, which is precise,
184 and drastically improves the performance of VMKit.</li>
185<li>Line number information in the JVM: by using the debug metadata of LLVM, the
186 JVM now supports precise line number information, useful when printing a stack
187 trace.</li>
188<li>Interface calls in the JVM: we implemented a variant of the Interface Method
189 Table technique for interface calls in the JVM.
190</li>
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000[diff] [blame]191
192</ul>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]193</div>
194
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]195
196<!--=========================================================================-->
197<div class="doc_subsection">
198<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
199</div>
200
201<div class="doc_text">
202<p>
203The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
204is a simple library that provides an implementation of the low-level
205target-specific hooks required by code generation and other runtime components.
206For example, when compiling for a 32-bit target, converting a double to a 64-bit
207unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
208function. The compiler-rt library provides highly optimized implementations of
209this and other low-level routines (some are 3x faster than the equivalent
210libgcc routines).</p>
211
212<p>
213All of the code in the compiler-rt project is available under the standard LLVM
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]214License, a "BSD-style" license. New in LLVM 2.7: compiler_rt now
215supports ARM targets.</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]216
217</div>
218
219<!--=========================================================================-->
220<div class="doc_subsection">
Duncan Sands2d9c3082010-04-02 09:23:15 +0000[diff] [blame]221<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]222</div>
223
224<div class="doc_text">
225<p>
Duncan Sands2d9c3082010-04-02 09:23:15 +0000[diff] [blame]226<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
227gcc-4.5. Unlike llvm-gcc, which makes many intrusive changes to the underlying
228gcc-4.2 code, dragonegg in theory does not require any gcc-4.5 modifications
229whatsoever (currently one small patch is needed). This is thanks to the new
230<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>, which
231makes it possible to modify the behaviour of gcc at runtime by loading a plugin,
232which is nothing more than a dynamic library which conforms to the gcc plugin
233interface. DragonEgg is a gcc plugin that causes the LLVM optimizers to be run
234instead of the gcc optimizers, and the LLVM code generators instead of the gcc
235code generators, just like llvm-gcc. To use it, you add
236"-fplugin=path/dragonegg.so" to the gcc-4.5 command line, and gcc-4.5 magically
237becomes llvm-gcc-4.5!
238</p>
239
240<p>
241DragonEgg is still a work in progress. Currently C works very well, while C++,
242Ada and Fortran work fairly well. All other languages either don't work at all,
243or only work poorly. For the moment only the x86-32 and x86-64 targets are
Duncan Sands566f40b2010-04-20 19:40:58 +0000[diff] [blame]244supported, and only on linux and darwin (darwin needs an additional gcc patch).
Duncan Sands2d9c3082010-04-02 09:23:15 +0000[diff] [blame]245</p>
246
247<p>
Duncan Sandsa9cc3892010-04-21 13:51:48 +0000[diff] [blame]248DragonEgg is a new project which is seeing its first release with llvm-2.7.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]249</p>
250
251</div>
252
253
254<!--=========================================================================-->
255<div class="doc_subsection">
256<a name="mc">llvm-mc: Machine Code Toolkit</a>
257</div>
258
259<div class="doc_text">
260<p>
Chris Lattnerfa63e262010-04-22 06:38:11 +0000[diff] [blame]261The LLVM Machine Code (aka MC) sub-project of LLVM was created to solve a number
262of problems in the realm of assembly, disassembly, object file format handling,
263and a number of other related areas that CPU instruction-set level tools work
264in. It is a sub-project of LLVM which provides it with a number of advantages
265over other compilers that do not have tightly integrated assembly-level tools.
266For a gentle introduction, please see the <a
267href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
268LLVM MC Project Blog Post</a>.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]269</p>
270
Chris Lattnerfa63e262010-04-22 06:38:11 +0000[diff] [blame]271<p>2.7 includes major parts of the work required by the new MC Project. A few
272 targets have been refactored to support it, and work is underway to support a
273 native assembler in LLVM. This work is not complete in LLVM 2.7, but you has
274 made substantially more progress on LLVM mainline.</p>
275
276<p>One minor example of what MC can do is to transcode an AT&amp;T syntax
Gabor Greifadba54d2010-04-22 10:25:23 +0000[diff] [blame]277 X86 .s file into intel syntax. You can do this with something like:</p>
Chris Lattnerfa63e262010-04-22 06:38:11 +0000[diff] [blame]278<pre>
279 llvm-mc foo.s -output-asm-variant=1 -o foo-intel.s
280</pre>
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]281
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]282</div>
283
284
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]285<!-- *********************************************************************** -->
286<div class="doc_section">
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]287 <a name="externalproj">External Open Source Projects Using LLVM 2.7</a>
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]288</div>
289<!-- *********************************************************************** -->
290
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]291<div class="doc_text">
292
293<p>An exciting aspect of LLVM is that it is used as an enabling technology for
294 a lot of other language and tools projects. This section lists some of the
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]295 projects that have already been updated to work with LLVM 2.7.</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]296</div>
297
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]298<!--=========================================================================-->
299<div class="doc_subsection">
300<a name="pure">Pure</a>
301</div>
302
303<div class="doc_text">
304<p>
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]305<a href="http://pure-lang.googlecode.com/">Pure</a>
306is an algebraic/functional programming language based on term rewriting.
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]307Programs are collections of equations which are used to evaluate expressions in
308a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame]309lexical closures, a hygienic macro system (also based on term rewriting),
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]310built-in list and matrix support (including list and matrix comprehensions) and
311an easy-to-use C interface. The interpreter uses LLVM as a backend to
312 JIT-compile Pure programs to fast native code.</p>
313
Chris Lattner1f8dc512010-03-17 17:25:49 +0000[diff] [blame]314<p>Pure versions 0.43 and later have been tested and are known to work with
315LLVM 2.7 (and continue to work with older LLVM releases >= 2.5).</p>
316
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]317</div>
318
Chris Lattner1ad599a2009-02-28 18:58:01 +0000[diff] [blame]319<!--=========================================================================-->
320<div class="doc_subsection">
321<a name="RoadsendPHP">Roadsend PHP</a>
322</div>
323
324<div class="doc_text">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]325<p>
326<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
Chris Lattner9e08de12009-03-02 19:07:24 +0000[diff] [blame]327source implementation of the PHP programming
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]328language that uses LLVM for its optimizer, JIT and static compiler. This is a
Chris Lattnere5236102010-03-17 04:02:39 +0000[diff] [blame]329reimplementation of an earlier project that is now based on LLVM.
Chris Lattner1f8dc512010-03-17 17:25:49 +0000[diff] [blame]330</p>
Chris Lattner1ad599a2009-02-28 18:58:01 +0000[diff] [blame]331</div>
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]332
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]333<!--=========================================================================-->
334<div class="doc_subsection">
335<a name="UnladenSwallow">Unladen Swallow</a>
336</div>
337
338<div class="doc_text">
339<p>
340<a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
341branch of <a href="http://python.org/">Python</a> intended to be fully
342compatible and significantly faster. It uses LLVM's optimization passes and JIT
Chris Lattnerd7db82c2010-03-18 06:52:15 +0000[diff] [blame]343compiler.
Chris Lattnere5236102010-03-17 04:02:39 +0000[diff] [blame]344</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]345</div>
346
347<!--=========================================================================-->
348<div class="doc_subsection">
Chris Lattner49894862010-03-29 17:50:39 +0000[diff] [blame]349<a name="tce">TTA-based Codesign Environment (TCE)</a>
350</div>
351
352<div class="doc_text">
353<p>
354<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing
355application-specific processors (ASP) based on the Transport triggered
356architecture (TTA). The toolset provides a complete co-design flow from C/C++
357programs down to synthesizable VHDL and parallel program binaries. Processor
358customization points include the register files, function units, supported
359operations, and the interconnection network.</p>
360
361<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target
362independent optimizations and also for parts of code generation. It generates
363new LLVM-based code generators "on the fly" for the designed TTA processors and
364loads them in to the compiler backend as runtime libraries to avoid per-target
365recompilation of larger parts of the compiler chain.</p>
366
367</div>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]368
John Criswelle75f04f2010-04-06 14:52:14 +0000[diff] [blame]369<!--=========================================================================-->
370<div class="doc_subsection">
371<a name="safecode">SAFECode Compiler</a>
372</div>
373
374<div class="doc_text">
375<p>
376<a href="http://safecode.cs.illinois.edu">SAFECode</a> is a memory safe C
377compiler built using LLVM. It takes standard, unannotated C code, analyzes the
378code to ensure that memory accesses and array indexing operations are safe, and
379instruments the code with run-time checks when safety cannot be proven
380statically.
381</p>
382</div>
383
384
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]385<!-- *********************************************************************** -->
386<div class="doc_section">
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]387 <a name="whatsnew">What's New in LLVM 2.7?</a>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]388</div>
389<!-- *********************************************************************** -->
390
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]391<div class="doc_text">
392
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]393<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]394minor improvements. Some of the major improvements and new features are listed
395in this section.
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]396</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]397
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]398</div>
399
400<!--=========================================================================-->
401<div class="doc_subsection">
402<a name="orgchanges">LLVM Community Changes</a>
403</div>
404
405<div class="doc_text">
406
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]407<p>In addition to changes to the code, between LLVM 2.6 and 2.7, a number of
408organization changes have happened:
409</p>
410
411<ul>
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]412<li>LLVM has a new <a href="http://llvm.org/Logo.html">official logo</a>!</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]413
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]414<li>Ted Kremenek and Doug Gregor have stepped forward as <a
415 href="http://llvm.org/docs/DeveloperPolicy.html#owners">Code Owners</a> of the
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]416 Clang static analyzer and the Clang frontend, respectively.</li>
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]417
418<li>LLVM now has an <a href="http://blog.llvm.org">official Blog</a> at
419 <a href="http://blog.llvm.org">http://blog.llvm.org</a>. This is a great way
420 to learn about new LLVM-related features as they are implemented. Several
421 features in this release are already explained on the blog.</li>
422
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]423<li>The LLVM web pages are now checked into the SVN server, in the "www",
424 "www-pubs" and "www-releases" SVN modules. Previously they were hidden in a
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]425 largely inaccessible old CVS server.</li>
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]426
427<li><a href="http://llvm.org">llvm.org</a> is now hosted on a new (and much
428 faster) server. It is still graciously hosted at the University of Illinois
429 of Urbana Champaign.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]430</ul>
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]431</div>
432
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]433<!--=========================================================================-->
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]434<div class="doc_subsection">
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]435<a name="majorfeatures">Major New Features</a>
436</div>
437
438<div class="doc_text">
439
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]440<p>LLVM 2.7 includes several major new capabilities:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]441
442<ul>
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]443<li>2.7 includes initial support for the <a
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]444 href="http://en.wikipedia.org/wiki/MicroBlaze">MicroBlaze</a> target.
445 MicroBlaze is a soft processor core designed for Xilinx FPGAs.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]446
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]447<li>2.7 includes a new LLVM IR "extensible metadata" feature. This feature
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]448 supports many different use cases, including allowing front-end authors to
449 encode source level information into LLVM IR, which is consumed by later
450 language-specific passes. This is a great way to do high-level optimizations
451 like devirtualization, type-based alias analysis, etc. See the <a
452 href="http://blog.llvm.org/2010/04/extensible-metadata-in-llvm-ir.html">
453 Extensible Metadata Blog Post</a> for more information.</li>
454
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]455<li>2.7 encodes <a href="SourceLevelDebugging.html">debug information</a>
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]456in a completely new way, built on extensible metadata. The new implementation
457is much more memory efficient and paves the way for improvements to optimized
458code debugging experience.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]459
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]460<li>2.7 now directly supports taking the address of a label and doing an
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]461 indirect branch through a pointer. This is particularly useful for
462 interpreter loops, and is used to implement the GCC "address of label"
463 extension. For more information, see the <a
464href="http://blog.llvm.org/2010/01/address-of-label-and-indirect-branches.html">
465Address of Label and Indirect Branches in LLVM IR Blog Post</a>.
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]466
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]467<li>2.7 is the first release to start supporting APIs for assembling and
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]468 disassembling target machine code. These APIs are useful for a variety of
469 low level clients, and are surfaced in the new "enhanced disassembly" API.
470 For more information see the <a
471 href="http://blog.llvm.org/2010/01/x86-disassembler.html">The X86
472 Disassembler Blog Post</a> for more information.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]473
Chris Lattnerfa63e262010-04-22 06:38:11 +0000[diff] [blame]474<li>2.7 includes major parts of the work required by the new MC Project,
475 see the <a href="#mc">MC update above</a> for more information.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]476
Chris Lattner5ba16862008-02-10 08:18:42 +0000[diff] [blame]477</ul>
Chris Lattner2b656342010-03-17 06:41:58 +0000[diff] [blame]478
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]479</div>
480
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]481<!--=========================================================================-->
482<div class="doc_subsection">
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]483<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]484</div>
485
486<div class="doc_text">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]487<p>LLVM IR has several new features for better support of new targets and that
488expose new optimization opportunities:</p>
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]489
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]490<ul>
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]491<li>LLVM IR now supports a 16-bit "half float" data type through <a
492 href="LangRef.html#int_fp16">two new intrinsics</a> and APFloat support.</li>
493<li>LLVM IR supports two new <a href="LangRef.html#fnattrs">function
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]494 attributes</a>: inlinehint and alignstack(n). The former is a hint to the
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]495 optimizer that a function was declared 'inline' and thus the inliner should
496 weight it higher when considering inlining it. The later
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]497 indicates to the code generator that the function diverges from the platform
498 ABI on stack alignment.</li>
499<li>The new <a href="LangRef.html#int_objectsize">llvm.objectsize</a> intrinsic
500 allows the optimizer to infer the sizes of memory objects in some cases.
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]501 This intrinsic is used to implement the GCC <tt>__builtin_object_size</tt>
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]502 extension.</li>
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]503<li>LLVM IR now supports marking load and store instructions with <a
504 href="LangRef.html#i_load">"non-temporal" hints</a> (building on the new
505 metadata feature). This hint encourages the code
506 generator to generate non-temporal accesses when possible, which are useful
507 for code that is carefully managing cache behavior. Currently, only the
508 X86 backend provides target support for this feature.</li>
509
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]510<li>LLVM 2.7 has pre-alpha support for <a
Gabor Greifdd39cd12010-04-22 10:11:24 +0000[diff] [blame]511 href="LangRef.html#t_union">unions in LLVM IR</a>.
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]512 Unfortunately, this support is not really usable in 2.7, so if you're
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]513 interested in pushing it forward, please help contribute to LLVM mainline.</li>
Gabor Greif92d28ea2010-04-22 10:21:43 +0000[diff] [blame]514
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]515</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]516
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]517</div>
518
519<!--=========================================================================-->
520<div class="doc_subsection">
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]521<a name="optimizer">Optimizer Improvements</a>
522</div>
523
524<div class="doc_text">
525
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]526<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattnerea9c2242008-10-13 21:50:36 +0000[diff] [blame]527release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]528
529<ul>
530
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]531<li>The inliner reuses now merges arrays stack objects in different callees when
532 inlining multiple call sites into one function. This reduces the stack size
533 of the resultant function.</li>
534<li>The -basicaa alias analysis pass (which is the default) has been improved to
535 be less dependent on "type safe" pointers. It can now look through bitcasts
536 and other constructs more aggressively, allowing better load/store
537 optimization.</li>
538<li>The load elimination optimization in the GVN Pass [<a
539href="http://blog.llvm.org/2009/12/introduction-to-load-elimination-in-gvn.html">intro
540 blog post</a>] has been substantially improved to be more aggressive about
541 partial redundancy elimination and do more aggressive phi translation. Please
542 see the <a
543 href="http://blog.llvm.org/2009/12/advanced-topics-in-redundant-load.html">
544 Advanced Topics in Redundant Load Elimination with a Focus on PHI Translation
545 Blog Post</a> for more details.</li>
546<li>The module <a href="LangRef.html#datalayout">target data string</a> now
Wesley Peck63c86992010-04-22 13:28:34 +0000[diff] [blame]547 includes a notion of 'native' integer data types for the target. This
548 helps mid-level optimizations avoid promoting complex sequences of
549 operations to data types that are not natively supported (e.g. converting
550 i32 operations to i64 on 32-bit chips).</li>
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]551<li>The mid-level optimizer is now conservative when operating on a module with
552 no target data. Previously, it would default to SparcV9 settings, which is
553 not what most people expected.</li>
Chris Lattner556aac32010-04-21 06:42:24 +0000[diff] [blame]554<li>Jump threading is now much more aggressive at simplifying correlated
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]555 conditionals and threading blocks with otherwise complex logic. It has
556 subsumed the old "Conditional Propagation" pass, and -condprop has been
557 removed from LLVM 2.7.</li>
558<li>The -instcombine pass has been refactored from being one huge file to being
559 a library of its own. Internally, it uses a customized IRBuilder to clean
560 it up and simplify it.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]561
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]562<li>The optimal edge profiling pass is reliable and much more complete than in
563 2.6. It can be used with the llvm-prof tool but isn't wired up to the
564 llvm-gcc and clang command line options yet.</li>
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]565
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]566<li>A new experimental alias analysis implementation, -scev-aa, has been added.
567 It uses LLVM's Scalar Evolution implementation to do symbolic analysis of
568 pointer offset expressions to disambiguate pointers. It can catch a few
569 cases that basicaa cannot, particularly in complex loop nests.</li>
Chris Lattner556aac32010-04-21 06:42:24 +0000[diff] [blame]570
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]571<li>The default pass ordering has been tweaked for improved optimization
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]572 effectiveness.</li>
Chris Lattner556aac32010-04-21 06:42:24 +0000[diff] [blame]573
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]574</ul>
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]575
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]576</div>
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]577
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]578
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]579<!--=========================================================================-->
580<div class="doc_subsection">
581<a name="executionengine">Interpreter and JIT Improvements</a>
582</div>
Chris Lattnerea9c2242008-10-13 21:50:36 +0000[diff] [blame]583
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]584<div class="doc_text">
585
586<ul>
Wesley Peck0d7f61e2010-04-22 13:36:27 +0000[diff] [blame]587<li>The JIT now supports generating debug information and is compatible with
588the new GDB 7.0 (and later) interfaces for registering dynamically generated
589debug info.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]590
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]591<li>The JIT now <a href="http://llvm.org/PR5184">defaults
Jeffrey Yasskin40715142010-01-29 19:10:38 +0000[diff] [blame]592to compiling eagerly</a> to avoid a race condition in the lazy JIT.
593Clients that still want the lazy JIT can switch it on by calling
594<tt>ExecutionEngine::DisableLazyCompilation(false)</tt>.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]595
Jeffrey Yasskinc0577082010-02-11 01:07:39 +0000[diff] [blame]596<li>It is now possible to create more than one JIT instance in the same process.
597These JITs can generate machine code in parallel,
598although <a href="http://llvm.org/docs/ProgrammersManual.html#jitthreading">you
599still have to obey the other threading restrictions</a>.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]600
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]601</ul>
602
603</div>
604
605<!--=========================================================================-->
606<div class="doc_subsection">
Chris Lattner5f393542009-03-02 03:24:11 +0000[diff] [blame]607<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]608</div>
609
610<div class="doc_text">
611
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame]612<p>We have put a significant amount of work into the code generator
613infrastructure, which allows us to implement more aggressive algorithms and make
614it run faster:</p>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]615
616<ul>
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]617<li>The 'llc -asm-verbose' option (which is now the default) has been enhanced
618 to emit many useful comments to .s files indicating information about spill
619 slots and loop nest structure. This should make it much easier to read and
620 understand assembly files. This is wired up in llvm-gcc and clang to
621 the <tt>-fverbose-asm</tt> option.</li>
622
623<li>New LSR with "full strength reduction" mode. FIXME: Description?</li>
624
625<li>A new codegen level Common Subexpression Elimination pass (MachineCSE)
626 is available and enabled by default. It catches redundancies exposed by
627 lowering.</li>
628<li>A new pre-register-allocation tail duplication pass is available and enabled
629 by default, it can substantially improve branch prediction quality in some
630 cases.</li>
631<li>A new sign and zero extension optimization pass (OptimizeExtsPass)
632 is available and enabled by default. This pass can takes advantage
633 architecture features like x86-64 implicit zero extension behavior and
634 sub-registers.</li>
635<li>The code generator now supports a mode where it attempts to preserve the
636 order of instructions in the input code. This is important for source that
637 is hand scheduled and extremely sensitive to scheduling. It is compatible
638 with the GCC <tt>-fno-schedule-insns</tt> option.</li>
639<li>The target-independent code generator now supports generating code with
640 arbitrary numbers of result values. Returning more values than was
641 previously supported is handled by returning through a hidden pointer. In
642 2.7, only the X86 and XCore targets have adopted support for this
643 though.</li>
644<li>The code generator now supports generating code that follows the
645 <a href="LangRef.html#callingconv">Glasgow Haskell Compiler Calling
646 Convention</a> and ABI.</li>
647<li>The "<a href="CodeGenerator.html#selectiondag_select">DAG instruction
648 selection</a>" phase of the code generator has been largely rewritten for
649 2.7. Previously, tblgen spit out tons of C++ code which was compiled and
650 linked into the target to do the pattern matching, now it emits a much
651 smaller table which is read by the target-independent code. The primary
652 advantages of this approach is that the size and compile time of various
653 targets is much improved. The X86 code generator shrunk by 1.5MB of code,
654 for example.</li>
655<li>Almost the entire code generator has switched to emitting code through the
656 MC interfaces instead of printing textually to the .s file. This led to a
657 number of cleanups and speedups. In 2.7, debug an exception handling
658 information does not go through MC yet.</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]659</ul>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]660</div>
661
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]662<!--=========================================================================-->
663<div class="doc_subsection">
664<a name="x86">X86-32 and X86-64 Target Improvements</a>
665</div>
666
667<div class="doc_text">
668<p>New features of the X86 target include:
669</p>
670
671<ul>
Chris Lattner556aac32010-04-21 06:42:24 +0000[diff] [blame]672<li>The X86 backend now optimizes tails calls much more aggressively for
673 functions that use the standard C calling convention.</li>
674<li>The X86 backend now models scalar SSE registers as subregs of the SSE vector
675 registers, making the code generator more aggressive in cases where scalars
676 and vector types are mixed.</li>
Chris Lattner5f393542009-03-02 03:24:11 +0000[diff] [blame]677
Chris Lattner556aac32010-04-21 06:42:24 +0000[diff] [blame]678<li>PostRA scheduler for X86? FIXME: is this on by default in 2.7?</li>
Chris Lattner5f393542009-03-02 03:24:11 +0000[diff] [blame]679
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]680</ul>
681
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]682</div>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]683
684<!--=========================================================================-->
685<div class="doc_subsection">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]686<a name="ARM">ARM Target Improvements</a>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]687</div>
688
689<div class="doc_text">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]690<p>New features of the ARM target include:
691</p>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]692
693<ul>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]694
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]695<li>The ARM backend now generates instructions in unified assembly syntax.</li>
696
697<li>llvm-gcc now has complete support for the ARM v7 NEON instruction set. This
698 support differs slightly from the GCC implementation. Please see the
699 <a
700href="http://blog.llvm.org/2010/04/arm-advanced-simd-neon-intrinsics-and.html">
701 ARM Advanced SIMD (NEON) Intrinsics and Types in LLVM Blog Post</a> for
702 helpful information if migrating code from GCC to LLVM-GCC.</li>
703
Wesley Peck0e9beac2010-04-22 13:43:14 +0000[diff] [blame]704<li>The ARM and Thumb code generators now use register scavenging for stack
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]705 object address materialization.(FIXME: WHAT BENEFIT DOES THIS PROVIDE?)</li>
706
Wesley Peck0e9beac2010-04-22 13:43:14 +0000[diff] [blame]707<li>The ARM backend now has good support for ARMv4 targets and has been tested
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]708 on StrongARM hardware. Previously, LLVM only supported ARMv4T and
709 newer chips.</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]710</ul>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]711
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]712
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]713</div>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]714
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]715<!--=========================================================================-->
716<div class="doc_subsection">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]717<a name="newapis">New Useful APIs</a>
718</div>
719
720<div class="doc_text">
721
722<p>This release includes a number of new APIs that are used internally, which
723 may also be useful for external clients.
724</p>
725
726<ul>
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]727<li>The optimizer uses the new CodeMetrics class to measure the size of code.
728 Various passes that use thing (like the inliner, loop unswitcher, etc) all
729 use this to make more accurate estimates of the code size impact of various
730 optimizations.</li>
731<li>A new <a href="http://llvm.org/doxygen/InstructionSimplify_8h-source.html">
Wesley Peck7b6a2ec2010-04-22 13:50:46 +0000[diff] [blame]732 llvm/Analysis/InstructionSimplify.h</a> interface is available for doing
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]733 symbolic simplification of instructions (e.g. <tt>a+0</tt> -&gt; <tt>a</tt>)
734 without requiring the instruction to exist. This centralizes a lot of
735 ad-hoc symbolic manipulation code scattered in various passes.</li>
736<li>The optimizer now uses a new <a
737 href="http://llvm.org/doxygen/SSAUpdater_8h-source.html">SSAUpdater</a>
738 class which efficiently supports
739 doing unstructured SSA update operations. This centralized a bunch of code
Wesley Peck7b6a2ec2010-04-22 13:50:46 +0000[diff] [blame]740 scattered throughout various passes (e.g. jump threading, lcssa,
741 loop rotate, etc) for doing this sort of thing. The code generator has a
742 similar <a href="http://llvm.org/doxygen/MachineSSAUpdater_8h-source.html">
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]743 MachineSSAUpdater</a> class.</li>
744<li>The <a href="http://llvm.org/doxygen/Regex_8h-source.html">
745 llvm/Support/Regex.h</a> header exposes a platform independent regular
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]746 expression API. Building on this, the <a
747 href="TestingGuide.html#FileCheck">FileCheck</a> utility now supports
748 regular exressions.</li>
749<li>raw_ostream now supports a circular "debug stream" accessed with "dbgs()".
750 By default, this stream works the same way as "errs()", but if you pass
751 <tt>-debug-buffer-size=1000</tt> to opt, the debug stream is capped to a
752 fixed sized circular buffer and the output is printed at the end of the
753 program's execution. This is helpful if you have a long lived compiler
754 process and you're interested in seeing snapshots in time.</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]755</ul>
756
757
758</div>
759
760<!--=========================================================================-->
761<div class="doc_subsection">
762<a name="otherimprovements">Other Improvements and New Features</a>
763</div>
764
765<div class="doc_text">
766<p>Other miscellaneous features include:</p>
767
768<ul>
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]769<li>You can now build LLVM as a big dynamic library (e.g. "libllvm2.7.so"). To
770 get this, configure LLVM with the --enable-shared option.</li>
771
Wesley Pecka85292d2010-04-22 13:53:54 +0000[diff] [blame]772<li>LLVM command line tools now overwrite their output by default. Previously,
773 they would only do this with -f. This makes them more convenient to use, and
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]774 behave more like standard unix tools.</li>
775
776<li>The opt and llc tools now autodetect whether their input is a .ll or .bc
777 file, and automatically do the right thing. This means you don't need to
778 explicitly use the llvm-as tool for most things.</li>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]779</ul>
780
781</div>
782
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]783
784<!--=========================================================================-->
785<div class="doc_subsection">
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]786<a name="changes">Major Changes and Removed Features</a>
787</div>
788
789<div class="doc_text">
790
Chris Lattnercc64a322008-10-13 22:06:31 +0000[diff] [blame]791<p>If you're already an LLVM user or developer with out-of-tree changes based
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]792on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading
Chris Lattnercc64a322008-10-13 22:06:31 +0000[diff] [blame]793from the previous release.</p>
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]794
795<ul>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]796
797<li>
798The Andersen's alias analysis ("anders-aa") pass, the Predicate Simplifier
799("predsimplify") pass, the LoopVR pass, the GVNPRE pass, and the random sampling
800profiling ("rsprofiling") passes have all been removed. They were not being
801actively maintained and had substantial problems. If you are interested in
802these components, you are welcome to ressurect them from SVN, fix the
803correctness problems, and resubmit them to mainline.</li>
804
805<li>LLVM now defaults to building most libraries with RTTI turned off, providing
806a code size reduction. Packagers who are interested in building LLVM to support
807plugins that require RTTI information should build with "make REQUIRE_RTTI=1"
808and should read the new <a href="Packaging.html">Advice on Packaging LLVM</a>
809document.</li>
810
Jeffrey Yasskin260af332010-02-09 23:03:44 +0000[diff] [blame]811<li>The LLVM interpreter now defaults to <em>not</em> using <tt>libffi</tt> even
812if you have it installed. This makes it more likely that an LLVM built on one
813system will work when copied to a similar system. To use <tt>libffi</tt>,
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]814configure with <tt>--enable-libffi</tt>.</li>
Chris Lattnercc64a322008-10-13 22:06:31 +0000[diff] [blame]815
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]816<li>Debug information uses a completely different representation, an LLVM 2.6
817.bc file should work with LLVM 2.7, but debug info won't come forward.</li>
818
819<li>The LLVM 2.6 (and earlier) "malloc" and "free" instructions got removed,
820 along with LowerAllocations pass. Now you should just use a call to the
821 malloc and free functions in libc. These calls are optimized as well as
822 the old instructions were.</li>
823</ul>
Chris Lattnercc64a322008-10-13 22:06:31 +0000[diff] [blame]824
825<p>In addition, many APIs have changed in this release. Some of the major LLVM
826API changes are:</p>
827
828<ul>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]829<li>Just about everything has been converted to use raw_ostream instead of
830 std::ostream.</li>
831<li>llvm/ADT/iterator.h has been removed, just use &lt;iterator&gt;
832 instead.</li>
833<li>The Streams.h file and "DOUT" got removed, use "DEBUG(errs() &lt;&lt; ...);"
834 instead.</li>
Jeffrey Yasskin2ca16212010-01-28 01:41:20 +0000[diff] [blame]835<li><tt>ModuleProvider</tt> has been <a
Gabor Greif92d28ea2010-04-22 10:21:43 +0000[diff] [blame]836href="http://llvm.org/viewvc/llvm-project?view=rev&amp;revision=94686">removed</a>
Jeffrey Yasskin2ca16212010-01-28 01:41:20 +0000[diff] [blame]837and its methods moved to <tt>Module</tt> and <tt>GlobalValue</tt>.
838Most clients can remove uses of <tt>ExistingModuleProvider</tt>,
839replace <tt>getBitcodeModuleProvider</tt> with
840<tt>getLazyBitcodeModule</tt>, and pass their <tt>Module</tt> to
841functions that used to accept <tt>ModuleProvider</tt>. Clients who
842wrote their own <tt>ModuleProvider</tt>s will need to derive from
843<tt>GVMaterializer</tt> instead and use
844<tt>Module::setMaterializer</tt> to attach it to a
845<tt>Module</tt>.</li>
846
847<li><tt>GhostLinkage</tt> has given up the ghost.
848<tt>GlobalValue</tt>s that have not yet been read from their backing
849storage have the same linkage they will have after being read in.
850Clients must replace calls to
851<tt>GlobalValue::hasNotBeenReadFromBitcode</tt> with
852<tt>GlobalValue::isMaterializable</tt>.</li>
Daniel Dunbar61f41422010-02-10 04:09:52 +0000[diff] [blame]853
Daniel Dunbar369889a2010-02-14 01:47:19 +0000[diff] [blame]854<li>The <tt>llvm/Support/DataTypes.h</tt> header has moved
855to <tt>llvm/System/DataTypes.h</tt>.</li>
856
Duncan Sandsdd29fc82010-02-17 17:20:17 +0000[diff] [blame]857<li>The <tt>isInteger</tt>, <tt>isIntOrIntVector</tt>, <tt>isFloatingPoint</tt>,
858<tt>isFPOrFPVector</tt> and <tt>isFPOrFPVector</tt> methods have been renamed
859<tt>isIntegerTy</tt>, <tt>isIntOrIntVectorTy</tt>, <tt>isFloatingPointTy</tt>,
860<tt>isFPOrFPVectorTy</tt> and <tt>isFPOrFPVectorTy</tt> respectively.</li>
Devang Patel0e3da1a2008-10-14 20:03:43 +0000[diff] [blame]861</ul>
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]862
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]863</div>
864
865
866
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]867<!-- *********************************************************************** -->
868<div class="doc_section">
869 <a name="portability">Portability and Supported Platforms</a>
870</div>
871<!-- *********************************************************************** -->
872
873<div class="doc_text">
874
875<p>LLVM is known to work on the following platforms:</p>
876
877<ul>
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame]878<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]879 Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like
880 systems).</li>
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]881<li>PowerPC and X86-based Mac OS X systems, running 10.4 and above in 32-bit
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]882 and 64-bit modes.</li>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]883<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]884<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
885 support is available for native builds with Visual C++).</li>
Chris Lattner9235ce52009-10-16 16:30:58 +0000[diff] [blame]886<li>Sun x86 and AMD64 machines running Solaris 10, OpenSolaris 0906.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]887<li>Alpha-based machines running Debian GNU/Linux.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]888</ul>
889
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]890<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]891to the machine and operating system on which it is built. However, minor
892porting may be required to get LLVM to work on new platforms. We welcome your
893portability patches and reports of successful builds or error messages.</p>
894
895</div>
896
897<!-- *********************************************************************** -->
898<div class="doc_section">
899 <a name="knownproblems">Known Problems</a>
900</div>
901<!-- *********************************************************************** -->
902
903<div class="doc_text">
904
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame]905<p>This section contains significant known problems with the LLVM system,
Chris Lattnerb1ad47c2008-11-10 05:40:34 +0000[diff] [blame]906listed by component. If you run into a problem, please check the <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]907href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
908there isn't already one.</p>
909
Chris Lattner1f8dc512010-03-17 17:25:49 +0000[diff] [blame]910<ul>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]911<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
912using the stock GCC 3.x.x series 'out the box',
Chris Lattnerc09ffd22009-11-03 21:50:09 +0000[diff] [blame]913See: <a href="GettingStarted.html#brokengcc">Broken versions of GCC and other tools</a>.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]914However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
915for x86/x86-64 has been made available from the third party AuroraUX Project
916that has been meticulously tested for bootstrapping LLVM &amp; Clang.</li>
917</ul>
918
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]919</div>
920
921<!-- ======================================================================= -->
922<div class="doc_subsection">
923 <a name="experimental">Experimental features included with this release</a>
924</div>
925
926<div class="doc_text">
927
928<p>The following components of this LLVM release are either untested, known to
929be broken or unreliable, or are in early development. These components should
930not be relied on, and bugs should not be filed against them, but they may be
931useful to some people. In particular, if you would like to work on one of these
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]932components, please contact us on the <a
933href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]934
935<ul>
Wesley Peckbe6dc822010-03-18 14:31:30 +0000[diff] [blame]936<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
937 backends are experimental.</li>
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]938<li><tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000[diff] [blame]939 supported value for this option. The MachO writer is experimental, and
940 works much better in mainline SVN.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]941</ul>
942
943</div>
944
945<!-- ======================================================================= -->
946<div class="doc_subsection">
947 <a name="x86-be">Known problems with the X86 back-end</a>
948</div>
949
950<div class="doc_text">
951
952<ul>
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000[diff] [blame]953 <li>The X86 backend does not yet support
954 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
955 floating point stack</a>. It supports the 'f' and 't' constraints, but not
956 'u'.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]957 <li>The X86 backend generates inefficient floating point code when configured
958 to generate code for systems that don't have SSE2.</li>
Duncan Sands8b4f3772008-06-08 19:38:43 +0000[diff] [blame]959 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswellaea8c752009-03-02 15:28:15 +0000[diff] [blame]960 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]961 runtime currently due to lack of support for the 'u' inline assembly
962 constraint and for X87 floating point inline assembly.</li>
Dan Gohman3882ecb2008-06-08 23:05:11 +0000[diff] [blame]963 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]964 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman3882ecb2008-06-08 23:05:11 +0000[diff] [blame]965 argument constructs on X86-64 by lowering them manually.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]966</ul>
967
968</div>
969
970<!-- ======================================================================= -->
971<div class="doc_subsection">
972 <a name="ppc-be">Known problems with the PowerPC back-end</a>
973</div>
974
975<div class="doc_text">
976
977<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]978<li>The Linux PPC32/ABI support needs testing for the interpreter and static
979compilation, and lacks support for debug information.</li>
980</ul>
981
982</div>
983
984<!-- ======================================================================= -->
985<div class="doc_subsection">
986 <a name="arm-be">Known problems with the ARM back-end</a>
987</div>
988
989<div class="doc_text">
990
991<ul>
992<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]993processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]994results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswellaea8c752009-03-02 15:28:15 +0000[diff] [blame]995<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]996</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]997</ul>
998
999</div>
1000
1001<!-- ======================================================================= -->
1002<div class="doc_subsection">
1003 <a name="sparc-be">Known problems with the SPARC back-end</a>
1004</div>
1005
1006<div class="doc_text">
1007
1008<ul>
John Criswellaea8c752009-03-02 15:28:15 +0000[diff] [blame]1009<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1010 support the 64-bit SPARC ABI (-m64).</li>
1011</ul>
1012
1013</div>
1014
1015<!-- ======================================================================= -->
1016<div class="doc_subsection">
Bruno Cardoso Lopes62d45d72008-10-25 14:56:26 +0000[diff] [blame]1017 <a name="mips-be">Known problems with the MIPS back-end</a>
1018</div>
1019
1020<div class="doc_text">
1021
1022<ul>
Bruno Cardoso Lopes62d45d72008-10-25 14:56:26 +0000[diff] [blame]1023<li>64-bit MIPS targets are not supported yet.</li>
1024</ul>
1025
1026</div>
1027
1028<!-- ======================================================================= -->
1029<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1030 <a name="alpha-be">Known problems with the Alpha back-end</a>
1031</div>
1032
1033<div class="doc_text">
1034
1035<ul>
1036
1037<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
1038appropriate nops inserted to ensure restartability.</li>
1039
1040</ul>
1041</div>
1042
1043<!-- ======================================================================= -->
1044<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1045 <a name="c-be">Known problems with the C back-end</a>
1046</div>
1047
1048<div class="doc_text">
1049
1050<ul>
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]1051<li><a href="http://llvm.org/PR802">The C backend has only basic support for
1052 inline assembly code</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]1053<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
1054 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greife33c5322009-03-02 12:02:51 +0000[diff] [blame]1055 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandsbd0ad6e2008-02-10 13:40:55 +0000[diff] [blame]1056<li>The C backend does not support all exception handling constructs.</li>
Duncan Sandse6e264c2009-02-25 11:51:54 +0000[diff] [blame]1057<li>The C backend does not support arbitrary precision integers.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1058</ul>
1059
1060</div>
1061
1062
1063<!-- ======================================================================= -->
1064<div class="doc_subsection">
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000[diff] [blame]1065 <a name="c-fe">Known problems with the llvm-gcc C and C++ front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1066</div>
1067
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1068<div class="doc_text">
1069
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]1070<p>The only major language feature of GCC not supported by llvm-gcc is
1071 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
1072 are only supported on some targets. For example, trampolines are only
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]1073 supported on some targets (these are used when you take the address of a
1074 nested function).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1075
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1076</div>
1077
1078<!-- ======================================================================= -->
1079<div class="doc_subsection">
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000[diff] [blame]1080 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
1081</div>
1082
1083<div class="doc_text">
Gabor Greif1fc8fbc2008-11-04 21:50:59 +0000[diff] [blame]1084<ul>
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000[diff] [blame]1085<li>Fortran support generally works, but there are still several unresolved bugs
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]1086 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
1087 tools/gfortran component for details.</li>
Gabor Greif1fc8fbc2008-11-04 21:50:59 +0000[diff] [blame]1088</ul>
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000[diff] [blame]1089</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1090
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]1091<!-- ======================================================================= -->
1092<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]1093 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]1094</div>
1095
1096<div class="doc_text">
John Criswellaea8c752009-03-02 15:28:15 +0000[diff] [blame]1097The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
1098technology, and problems should be expected.
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]1099<ul>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]1100<li>The Ada front-end currently only builds on X86-32. This is mainly due
John Criswellaea8c752009-03-02 15:28:15 +0000[diff] [blame]1101to lack of trampoline support (pointers to nested functions) on other platforms.
1102However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]1103which does support trampolines.</li>
1104<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
Duncan Sandsf73473e2009-02-25 11:59:06 +0000[diff] [blame]1105This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
1106exception handling, which is used internally by the compiler.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]1107Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
Duncan Sands2dbc2e82008-10-13 17:27:23 +0000[diff] [blame]1108<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
1109and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sandsf73473e2009-02-25 11:59:06 +0000[diff] [blame]1110(c380004 also fails with gcc-4.2 mainline).
1111If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
1112causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sandsc2a29a02009-03-02 16:35:57 +0000[diff] [blame]1113<li>Some GCC specific Ada tests continue to crash the compiler.</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]1114<li>The <tt>-E</tt> binder option (exception backtraces)
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]1115<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]1116crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]1117<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
1118or finish at a non-byte offset</a> in a record. Workaround: do not pack records
1119or use representation clauses that result in a field of a non-discrete type
1120starting or finishing in the middle of a byte.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]1121<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
1122'main' as generated by the Ada binder to be invalid</a>.
1123Workaround: hand edit the file to use pointers for <tt>argv</tt> and
1124<tt>envp</tt> rather than integers.</li>
1125<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
1126ignored</a>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]1127</ul>
1128</div>
1129
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1130<!-- *********************************************************************** -->
1131<div class="doc_section">
1132 <a name="additionalinfo">Additional Information</a>
1133</div>
1134<!-- *********************************************************************** -->
1135
1136<div class="doc_text">
1137
1138<p>A wide variety of additional information is available on the <a
1139href="http://llvm.org">LLVM web page</a>, in particular in the <a
1140href="http://llvm.org/docs/">documentation</a> section. The web page also
1141contains versions of the API documentation which is up-to-date with the
1142Subversion version of the source code.
1143You can access versions of these documents specific to this release by going
1144into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
1145
1146<p>If you have any questions or comments about LLVM, please feel free to contact
1147us via the <a href="http://llvm.org/docs/#maillist"> mailing
1148lists</a>.</p>
1149
1150</div>
1151
1152<!-- *********************************************************************** -->
1153
1154<hr>
1155<address>
1156 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]1157 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1158 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]1159 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1160
1161 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
1162 Last modified: $Date$
1163</address>
1164
1165</body>
1166</html>