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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 2f3b628d6575922a066ed2368f2cb6ab78937a1a / . / docs / ReleaseNotes.html
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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3<html>
4<head>
5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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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"
14 width="136" height="136">
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>
130documentation for more details. The CIndex API also includings an preliminary
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
277 X86 .s file into intel syntax. You can do this with something like:</p>
278
279<pre>
280 llvm-mc foo.s -output-asm-variant=1 -o foo-intel.s
281</pre>
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]282</p>
283
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]284</div>
285
286
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]287<!-- *********************************************************************** -->
288<div class="doc_section">
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]289 <a name="externalproj">External Open Source Projects Using LLVM 2.7</a>
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]290</div>
291<!-- *********************************************************************** -->
292
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]293<div class="doc_text">
294
295<p>An exciting aspect of LLVM is that it is used as an enabling technology for
296 a lot of other language and tools projects. This section lists some of the
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]297 projects that have already been updated to work with LLVM 2.7.</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]298</div>
299
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]300<!--=========================================================================-->
301<div class="doc_subsection">
302<a name="pure">Pure</a>
303</div>
304
305<div class="doc_text">
306<p>
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]307<a href="http://pure-lang.googlecode.com/">Pure</a>
308is an algebraic/functional programming language based on term rewriting.
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]309Programs are collections of equations which are used to evaluate expressions in
310a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame]311lexical closures, a hygienic macro system (also based on term rewriting),
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]312built-in list and matrix support (including list and matrix comprehensions) and
313an easy-to-use C interface. The interpreter uses LLVM as a backend to
314 JIT-compile Pure programs to fast native code.</p>
315
Chris Lattner1f8dc512010-03-17 17:25:49 +0000[diff] [blame]316<p>Pure versions 0.43 and later have been tested and are known to work with
317LLVM 2.7 (and continue to work with older LLVM releases >= 2.5).</p>
318
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]319</div>
320
Chris Lattner1ad599a2009-02-28 18:58:01 +0000[diff] [blame]321<!--=========================================================================-->
322<div class="doc_subsection">
323<a name="RoadsendPHP">Roadsend PHP</a>
324</div>
325
326<div class="doc_text">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]327<p>
328<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
Chris Lattner9e08de12009-03-02 19:07:24 +0000[diff] [blame]329source implementation of the PHP programming
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]330language that uses LLVM for its optimizer, JIT and static compiler. This is a
Chris Lattnere5236102010-03-17 04:02:39 +0000[diff] [blame]331reimplementation of an earlier project that is now based on LLVM.
Chris Lattner1f8dc512010-03-17 17:25:49 +0000[diff] [blame]332</p>
Chris Lattner1ad599a2009-02-28 18:58:01 +0000[diff] [blame]333</div>
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000[diff] [blame]334
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]335<!--=========================================================================-->
336<div class="doc_subsection">
337<a name="UnladenSwallow">Unladen Swallow</a>
338</div>
339
340<div class="doc_text">
341<p>
342<a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
343branch of <a href="http://python.org/">Python</a> intended to be fully
344compatible and significantly faster. It uses LLVM's optimization passes and JIT
Chris Lattnerd7db82c2010-03-18 06:52:15 +0000[diff] [blame]345compiler.
Chris Lattnere5236102010-03-17 04:02:39 +0000[diff] [blame]346</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]347</div>
348
349<!--=========================================================================-->
350<div class="doc_subsection">
Chris Lattner49894862010-03-29 17:50:39 +0000[diff] [blame]351<a name="tce">TTA-based Codesign Environment (TCE)</a>
352</div>
353
354<div class="doc_text">
355<p>
356<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing
357application-specific processors (ASP) based on the Transport triggered
358architecture (TTA). The toolset provides a complete co-design flow from C/C++
359programs down to synthesizable VHDL and parallel program binaries. Processor
360customization points include the register files, function units, supported
361operations, and the interconnection network.</p>
362
363<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target
364independent optimizations and also for parts of code generation. It generates
365new LLVM-based code generators "on the fly" for the designed TTA processors and
366loads them in to the compiler backend as runtime libraries to avoid per-target
367recompilation of larger parts of the compiler chain.</p>
368
369</div>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]370
John Criswelle75f04f2010-04-06 14:52:14 +0000[diff] [blame]371<!--=========================================================================-->
372<div class="doc_subsection">
373<a name="safecode">SAFECode Compiler</a>
374</div>
375
376<div class="doc_text">
377<p>
378<a href="http://safecode.cs.illinois.edu">SAFECode</a> is a memory safe C
379compiler built using LLVM. It takes standard, unannotated C code, analyzes the
380code to ensure that memory accesses and array indexing operations are safe, and
381instruments the code with run-time checks when safety cannot be proven
382statically.
383</p>
384</div>
385
386
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]387<!-- *********************************************************************** -->
388<div class="doc_section">
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]389 <a name="whatsnew">What's New in LLVM 2.7?</a>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]390</div>
391<!-- *********************************************************************** -->
392
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]393<div class="doc_text">
394
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]395<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]396minor improvements. Some of the major improvements and new features are listed
397in this section.
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]398</p>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]399
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]400</div>
401
402<!--=========================================================================-->
403<div class="doc_subsection">
404<a name="orgchanges">LLVM Community Changes</a>
405</div>
406
407<div class="doc_text">
408
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]409<p>In addition to changes to the code, between LLVM 2.6 and 2.7, a number of
410organization changes have happened:
411</p>
412
413<ul>
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]414<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]415
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]416<li>Ted Kremenek and Doug Gregor have stepped forward as <a
417 href="http://llvm.org/docs/DeveloperPolicy.html#owners">Code Owners</a> of the
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]418 Clang static analyzer and the Clang frontend, respectively.</li>
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]419
420<li>LLVM now has an <a href="http://blog.llvm.org">official Blog</a> at
421 <a href="http://blog.llvm.org">http://blog.llvm.org</a>. This is a great way
422 to learn about new LLVM-related features as they are implemented. Several
423 features in this release are already explained on the blog.</li>
424
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]425<li>The LLVM web pages are now checked into the SVN server, in the "www",
426 "www-pubs" and "www-releases" SVN modules. Previously they were hidden in a
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]427 largely inaccessible old CVS server.</li>
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]428
429<li><a href="http://llvm.org">llvm.org</a> is now hosted on a new (and much
430 faster) server. It is still graciously hosted at the University of Illinois
431 of Urbana Champaign.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]432</ul>
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]433</div>
434
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]435<!--=========================================================================-->
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]436<div class="doc_subsection">
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]437<a name="majorfeatures">Major New Features</a>
438</div>
439
440<div class="doc_text">
441
Jeffrey Yasskin8ee1b0a2010-01-28 01:14:43 +0000[diff] [blame]442<p>LLVM 2.7 includes several major new capabilities:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]443
444<ul>
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]445<li>2.7 includes initial support for the <a
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]446 href="http://en.wikipedia.org/wiki/MicroBlaze">MicroBlaze</a> target.
447 MicroBlaze is a soft processor core designed for Xilinx FPGAs.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]448
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]449<li>2.7 includes a new LLVM IR "extensible metadata" feature. This feature
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]450 supports many different use cases, including allowing front-end authors to
451 encode source level information into LLVM IR, which is consumed by later
452 language-specific passes. This is a great way to do high-level optimizations
453 like devirtualization, type-based alias analysis, etc. See the <a
454 href="http://blog.llvm.org/2010/04/extensible-metadata-in-llvm-ir.html">
455 Extensible Metadata Blog Post</a> for more information.</li>
456
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]457<li>2.7 encodes <a href="SourceLevelDebugging.html">debug information</a>
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]458in a completely new way, built on extensible metadata. The new implementation
459is much more memory efficient and paves the way for improvements to optimized
460code debugging experience.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]461
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]462<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]463 indirect branch through a pointer. This is particularly useful for
464 interpreter loops, and is used to implement the GCC "address of label"
465 extension. For more information, see the <a
466href="http://blog.llvm.org/2010/01/address-of-label-and-indirect-branches.html">
467Address of Label and Indirect Branches in LLVM IR Blog Post</a>.
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]468
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]469<li>2.7 is the first release to start supporting APIs for assembling and
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]470 disassembling target machine code. These APIs are useful for a variety of
471 low level clients, and are surfaced in the new "enhanced disassembly" API.
472 For more information see the <a
473 href="http://blog.llvm.org/2010/01/x86-disassembler.html">The X86
474 Disassembler Blog Post</a> for more information.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]475
Chris Lattnerfa63e262010-04-22 06:38:11 +0000[diff] [blame]476<li>2.7 includes major parts of the work required by the new MC Project,
477 see the <a href="#mc">MC update above</a> for more information.</li>
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]478</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]479
Chris Lattner5ba16862008-02-10 08:18:42 +0000[diff] [blame]480</ul>
Chris Lattner2b656342010-03-17 06:41:58 +0000[diff] [blame]481
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]482</div>
483
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]484<!--=========================================================================-->
485<div class="doc_subsection">
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]486<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]487</div>
488
489<div class="doc_text">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]490<p>LLVM IR has several new features for better support of new targets and that
491expose new optimization opportunities:</p>
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]492
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]493<ul>
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]494<li>LLVM IR now supports a 16-bit "half float" data type through <a
495 href="LangRef.html#int_fp16">two new intrinsics</a> and APFloat support.</li>
496<li>LLVM IR supports two new <a href="LangRef.html#fnattrs">function
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]497 attributes</a>: inlinehint and alignstack(n). The former is a hint to the
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]498 optimizer that a function was declared 'inline' and thus the inliner should
499 weight it higher when considering inlining it. The later
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]500 indicates to the code generator that the function diverges from the platform
501 ABI on stack alignment.</li>
502<li>The new <a href="LangRef.html#int_objectsize">llvm.objectsize</a> intrinsic
503 allows the optimizer to infer the sizes of memory objects in some cases.
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]504 This intrinsic is used to implement the GCC <tt>__builtin_object_size</tt>
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]505 extension.</li>
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]506<li>LLVM IR now supports marking load and store instructions with <a
507 href="LangRef.html#i_load">"non-temporal" hints</a> (building on the new
508 metadata feature). This hint encourages the code
509 generator to generate non-temporal accesses when possible, which are useful
510 for code that is carefully managing cache behavior. Currently, only the
511 X86 backend provides target support for this feature.</li>
512
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]513<li>LLVM 2.7 has pre-alpha support for <a
514 href="http://llvm.org/docs/LangRef.html#t_union">unions in LLVM IR</a>.
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]515 Unfortunately, this support is not really usable in 2.7, so if you're
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]516 interested in pushing it forward, please help contribute to LLVM mainline.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]517</li>
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]518</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]519
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]520</div>
521
522<!--=========================================================================-->
523<div class="doc_subsection">
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]524<a name="optimizer">Optimizer Improvements</a>
525</div>
526
527<div class="doc_text">
528
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]529<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]530release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]531
532<ul>
533
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]534<li>The inliner reuses now merges arrays stack objects in different callees when
535 inlining multiple call sites into one function. This reduces the stack size
536 of the resultant function.</li>
537<li>The -basicaa alias analysis pass (which is the default) has been improved to
538 be less dependent on "type safe" pointers. It can now look through bitcasts
539 and other constructs more aggressively, allowing better load/store
540 optimization.</li>
541<li>The load elimination optimization in the GVN Pass [<a
542href="http://blog.llvm.org/2009/12/introduction-to-load-elimination-in-gvn.html">intro
543 blog post</a>] has been substantially improved to be more aggressive about
544 partial redundancy elimination and do more aggressive phi translation. Please
545 see the <a
546 href="http://blog.llvm.org/2009/12/advanced-topics-in-redundant-load.html">
547 Advanced Topics in Redundant Load Elimination with a Focus on PHI Translation
548 Blog Post</a> for more details.</li>
549<li>The module <a href="LangRef.html#datalayout">target data string</a> now
550 includes a notion of what the 'native' integer data types a for the target,
551 which allows various optimizations to use. This helps mid-level
552 optimizations avoid promoting complex sequences of operations to data types
553 that are not natively supported (e.g. converting i32 operations to i64 on
554 a 32-bit chip).</li>
555<li>The mid-level optimizer is now conservative when operating on a module with
556 no target data. Previously, it would default to SparcV9 settings, which is
557 not what most people expected.</li>
Chris Lattner556aac32010-04-21 06:42:24 +0000[diff] [blame]558<li>Jump threading is now much more aggressive at simplifying correlated
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]559 conditionals and threading blocks with otherwise complex logic. It has
560 subsumed the old "Conditional Propagation" pass, and -condprop has been
561 removed from LLVM 2.7.</li>
562<li>The -instcombine pass has been refactored from being one huge file to being
563 a library of its own. Internally, it uses a customized IRBuilder to clean
564 it up and simplify it.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]565
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]566<li>The optimal edge profiling pass is reliable and much more complete than in
567 2.6. It can be used with the llvm-prof tool but isn't wired up to the
568 llvm-gcc and clang command line options yet.</li>
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]569
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]570<li>A new experimental alias analysis implementation, -scev-aa, has been added.
571 It uses LLVM's Scalar Evolution implementation to do symbolic analysis of
572 pointer offset expressions to disambiguate pointers. It can catch a few
573 cases that basicaa cannot, particularly in complex loop nests.</li>
Chris Lattner556aac32010-04-21 06:42:24 +0000[diff] [blame]574
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]575<li>The default pass ordering has been tweaked for improved optimization
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]576 effectiveness.</li>
Chris Lattner556aac32010-04-21 06:42:24 +0000[diff] [blame]577
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]578</ul>
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]579
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]580</div>
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]581
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]582
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]583<!--=========================================================================-->
584<div class="doc_subsection">
585<a name="executionengine">Interpreter and JIT Improvements</a>
586</div>
Chris Lattnerea9c2242008-10-13 21:50:36 +0000[diff] [blame]587
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]588<div class="doc_text">
589
590<ul>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]591<li>The JIT now supports generating debug information, which is compatible with
592the new GDB 7.0 (and later) interfaces for registering debug info for
593dynamically generated code.</li>
594
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]595<li>The JIT now <a href="http://llvm.org/PR5184">defaults
Jeffrey Yasskin40715142010-01-29 19:10:38 +0000[diff] [blame]596to compiling eagerly</a> to avoid a race condition in the lazy JIT.
597Clients that still want the lazy JIT can switch it on by calling
598<tt>ExecutionEngine::DisableLazyCompilation(false)</tt>.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]599
Jeffrey Yasskinc0577082010-02-11 01:07:39 +0000[diff] [blame]600<li>It is now possible to create more than one JIT instance in the same process.
601These JITs can generate machine code in parallel,
602although <a href="http://llvm.org/docs/ProgrammersManual.html#jitthreading">you
603still have to obey the other threading restrictions</a>.</li>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]604
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]605</ul>
606
607</div>
608
609<!--=========================================================================-->
610<div class="doc_subsection">
Chris Lattner5f393542009-03-02 03:24:11 +0000[diff] [blame]611<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]612</div>
613
614<div class="doc_text">
615
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame]616<p>We have put a significant amount of work into the code generator
617infrastructure, which allows us to implement more aggressive algorithms and make
618it run faster:</p>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]619
620<ul>
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]621<li>The 'llc -asm-verbose' option (which is now the default) has been enhanced
622 to emit many useful comments to .s files indicating information about spill
623 slots and loop nest structure. This should make it much easier to read and
624 understand assembly files. This is wired up in llvm-gcc and clang to
625 the <tt>-fverbose-asm</tt> option.</li>
626
627<li>New LSR with "full strength reduction" mode. FIXME: Description?</li>
628
629<li>A new codegen level Common Subexpression Elimination pass (MachineCSE)
630 is available and enabled by default. It catches redundancies exposed by
631 lowering.</li>
632<li>A new pre-register-allocation tail duplication pass is available and enabled
633 by default, it can substantially improve branch prediction quality in some
634 cases.</li>
635<li>A new sign and zero extension optimization pass (OptimizeExtsPass)
636 is available and enabled by default. This pass can takes advantage
637 architecture features like x86-64 implicit zero extension behavior and
638 sub-registers.</li>
639<li>The code generator now supports a mode where it attempts to preserve the
640 order of instructions in the input code. This is important for source that
641 is hand scheduled and extremely sensitive to scheduling. It is compatible
642 with the GCC <tt>-fno-schedule-insns</tt> option.</li>
643<li>The target-independent code generator now supports generating code with
644 arbitrary numbers of result values. Returning more values than was
645 previously supported is handled by returning through a hidden pointer. In
646 2.7, only the X86 and XCore targets have adopted support for this
647 though.</li>
648<li>The code generator now supports generating code that follows the
649 <a href="LangRef.html#callingconv">Glasgow Haskell Compiler Calling
650 Convention</a> and ABI.</li>
651<li>The "<a href="CodeGenerator.html#selectiondag_select">DAG instruction
652 selection</a>" phase of the code generator has been largely rewritten for
653 2.7. Previously, tblgen spit out tons of C++ code which was compiled and
654 linked into the target to do the pattern matching, now it emits a much
655 smaller table which is read by the target-independent code. The primary
656 advantages of this approach is that the size and compile time of various
657 targets is much improved. The X86 code generator shrunk by 1.5MB of code,
658 for example.</li>
659<li>Almost the entire code generator has switched to emitting code through the
660 MC interfaces instead of printing textually to the .s file. This led to a
661 number of cleanups and speedups. In 2.7, debug an exception handling
662 information does not go through MC yet.</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]663</ul>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]664</div>
665
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]666<!--=========================================================================-->
667<div class="doc_subsection">
668<a name="x86">X86-32 and X86-64 Target Improvements</a>
669</div>
670
671<div class="doc_text">
672<p>New features of the X86 target include:
673</p>
674
675<ul>
Chris Lattner556aac32010-04-21 06:42:24 +0000[diff] [blame]676<li>The X86 backend now optimizes tails calls much more aggressively for
677 functions that use the standard C calling convention.</li>
678<li>The X86 backend now models scalar SSE registers as subregs of the SSE vector
679 registers, making the code generator more aggressive in cases where scalars
680 and vector types are mixed.</li>
Chris Lattner5f393542009-03-02 03:24:11 +0000[diff] [blame]681
Chris Lattner556aac32010-04-21 06:42:24 +0000[diff] [blame]682<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]683
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]684</ul>
685
Chris Lattner47202c32009-03-02 02:37:32 +0000[diff] [blame]686</div>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]687
688<!--=========================================================================-->
689<div class="doc_subsection">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]690<a name="ARM">ARM Target Improvements</a>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]691</div>
692
693<div class="doc_text">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]694<p>New features of the ARM target include:
695</p>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]696
697<ul>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]698
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]699<li>The ARM backend now generates instructions in unified assembly syntax.</li>
700
701<li>llvm-gcc now has complete support for the ARM v7 NEON instruction set. This
702 support differs slightly from the GCC implementation. Please see the
703 <a
704href="http://blog.llvm.org/2010/04/arm-advanced-simd-neon-intrinsics-and.html">
705 ARM Advanced SIMD (NEON) Intrinsics and Types in LLVM Blog Post</a> for
706 helpful information if migrating code from GCC to LLVM-GCC.</li>
707
708<li>The ARM and Thumb code generators now using register scavenging for stack
709 object address materialization.(FIXME: WHAT BENEFIT DOES THIS PROVIDE?)</li>
710
711<li>The ARM backend now has good support for ARMv4 targets, and has been tested
712 on StrongARM hardware. Previously, LLVM only supported ARMv4T and
713 newer chips.</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]714</ul>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]715
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]716
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]717</div>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]718
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]719<!--=========================================================================-->
720<div class="doc_subsection">
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]721<a name="newapis">New Useful APIs</a>
722</div>
723
724<div class="doc_text">
725
726<p>This release includes a number of new APIs that are used internally, which
727 may also be useful for external clients.
728</p>
729
730<ul>
Chris Lattnerabfaf732010-04-22 05:41:35 +0000[diff] [blame]731<li>The optimizer uses the new CodeMetrics class to measure the size of code.
732 Various passes that use thing (like the inliner, loop unswitcher, etc) all
733 use this to make more accurate estimates of the code size impact of various
734 optimizations.</li>
735<li>A new <a href="http://llvm.org/doxygen/InstructionSimplify_8h-source.html">
736 llvm/Analysis/InstructionSimplify.h</a> interface available for doing
737 symbolic simplification of instructions (e.g. <tt>a+0</tt> -&gt; <tt>a</tt>)
738 without requiring the instruction to exist. This centralizes a lot of
739 ad-hoc symbolic manipulation code scattered in various passes.</li>
740<li>The optimizer now uses a new <a
741 href="http://llvm.org/doxygen/SSAUpdater_8h-source.html">SSAUpdater</a>
742 class which efficiently supports
743 doing unstructured SSA update operations. This centralized a bunch of code
744 scattered through various passes (e.g. jump threading, lcssa, loop rotate,
745 etc) for doing this sort of thing. The code generator has an similar
746 <a href="http://llvm.org/doxygen/MachineSSAUpdater_8h-source.html">
747 MachineSSAUpdater</a> class.</li>
748<li>The <a href="http://llvm.org/doxygen/Regex_8h-source.html">
749 llvm/Support/Regex.h</a> header exposes a platform independent regular
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]750 expression API. Building on this, the <a
751 href="TestingGuide.html#FileCheck">FileCheck</a> utility now supports
752 regular exressions.</li>
753<li>raw_ostream now supports a circular "debug stream" accessed with "dbgs()".
754 By default, this stream works the same way as "errs()", but if you pass
755 <tt>-debug-buffer-size=1000</tt> to opt, the debug stream is capped to a
756 fixed sized circular buffer and the output is printed at the end of the
757 program's execution. This is helpful if you have a long lived compiler
758 process and you're interested in seeing snapshots in time.</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]759</ul>
760
761
762</div>
763
764<!--=========================================================================-->
765<div class="doc_subsection">
766<a name="otherimprovements">Other Improvements and New Features</a>
767</div>
768
769<div class="doc_text">
770<p>Other miscellaneous features include:</p>
771
772<ul>
Chris Lattner8a57e892010-04-21 06:23:40 +0000[diff] [blame]773<li>You can now build LLVM as a big dynamic library (e.g. "libllvm2.7.so"). To
774 get this, configure LLVM with the --enable-shared option.</li>
775
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]776<li>LLVM command line tools now overwrite their output by default, before they
777 would only do this with -f. This makes them more convenient to use, and
778 behave more like standard unix tools.</li>
779
780<li>The opt and llc tools now autodetect whether their input is a .ll or .bc
781 file, and automatically do the right thing. This means you don't need to
782 explicitly use the llvm-as tool for most things.</li>
Chris Lattner7ccc40d2009-03-01 02:30:21 +0000[diff] [blame]783</ul>
784
785</div>
786
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]787
788<!--=========================================================================-->
789<div class="doc_subsection">
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]790<a name="changes">Major Changes and Removed Features</a>
791</div>
792
793<div class="doc_text">
794
Chris Lattnercc64a322008-10-13 22:06:31 +0000[diff] [blame]795<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]796on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading
Chris Lattnercc64a322008-10-13 22:06:31 +0000[diff] [blame]797from the previous release.</p>
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]798
799<ul>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]800
801<li>
802The Andersen's alias analysis ("anders-aa") pass, the Predicate Simplifier
803("predsimplify") pass, the LoopVR pass, the GVNPRE pass, and the random sampling
804profiling ("rsprofiling") passes have all been removed. They were not being
805actively maintained and had substantial problems. If you are interested in
806these components, you are welcome to ressurect them from SVN, fix the
807correctness problems, and resubmit them to mainline.</li>
808
809<li>LLVM now defaults to building most libraries with RTTI turned off, providing
810a code size reduction. Packagers who are interested in building LLVM to support
811plugins that require RTTI information should build with "make REQUIRE_RTTI=1"
812and should read the new <a href="Packaging.html">Advice on Packaging LLVM</a>
813document.</li>
814
Jeffrey Yasskin260af332010-02-09 23:03:44 +0000[diff] [blame]815<li>The LLVM interpreter now defaults to <em>not</em> using <tt>libffi</tt> even
816if you have it installed. This makes it more likely that an LLVM built on one
817system will work when copied to a similar system. To use <tt>libffi</tt>,
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]818configure with <tt>--enable-libffi</tt>.</li>
Chris Lattnercc64a322008-10-13 22:06:31 +0000[diff] [blame]819
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]820<li>Debug information uses a completely different representation, an LLVM 2.6
821.bc file should work with LLVM 2.7, but debug info won't come forward.</li>
822
823<li>The LLVM 2.6 (and earlier) "malloc" and "free" instructions got removed,
824 along with LowerAllocations pass. Now you should just use a call to the
825 malloc and free functions in libc. These calls are optimized as well as
826 the old instructions were.</li>
827</ul>
Chris Lattnercc64a322008-10-13 22:06:31 +0000[diff] [blame]828
829<p>In addition, many APIs have changed in this release. Some of the major LLVM
830API changes are:</p>
831
832<ul>
Chris Lattner6fd928d2010-04-21 05:17:40 +0000[diff] [blame]833<li>Just about everything has been converted to use raw_ostream instead of
834 std::ostream.</li>
835<li>llvm/ADT/iterator.h has been removed, just use &lt;iterator&gt;
836 instead.</li>
837<li>The Streams.h file and "DOUT" got removed, use "DEBUG(errs() &lt;&lt; ...);"
838 instead.</li>
Jeffrey Yasskin2ca16212010-01-28 01:41:20 +0000[diff] [blame]839<li><tt>ModuleProvider</tt> has been <a
840href="http://llvm.org/viewvc/llvm-project?view=rev&revision=94686">removed</a>
841and its methods moved to <tt>Module</tt> and <tt>GlobalValue</tt>.
842Most clients can remove uses of <tt>ExistingModuleProvider</tt>,
843replace <tt>getBitcodeModuleProvider</tt> with
844<tt>getLazyBitcodeModule</tt>, and pass their <tt>Module</tt> to
845functions that used to accept <tt>ModuleProvider</tt>. Clients who
846wrote their own <tt>ModuleProvider</tt>s will need to derive from
847<tt>GVMaterializer</tt> instead and use
848<tt>Module::setMaterializer</tt> to attach it to a
849<tt>Module</tt>.</li>
850
851<li><tt>GhostLinkage</tt> has given up the ghost.
852<tt>GlobalValue</tt>s that have not yet been read from their backing
853storage have the same linkage they will have after being read in.
854Clients must replace calls to
855<tt>GlobalValue::hasNotBeenReadFromBitcode</tt> with
856<tt>GlobalValue::isMaterializable</tt>.</li>
Daniel Dunbar61f41422010-02-10 04:09:52 +0000[diff] [blame]857
Daniel Dunbar369889a2010-02-14 01:47:19 +0000[diff] [blame]858<li>The <tt>llvm/Support/DataTypes.h</tt> header has moved
859to <tt>llvm/System/DataTypes.h</tt>.</li>
860
Duncan Sandsdd29fc82010-02-17 17:20:17 +0000[diff] [blame]861<li>The <tt>isInteger</tt>, <tt>isIntOrIntVector</tt>, <tt>isFloatingPoint</tt>,
862<tt>isFPOrFPVector</tt> and <tt>isFPOrFPVector</tt> methods have been renamed
863<tt>isIntegerTy</tt>, <tt>isIntOrIntVectorTy</tt>, <tt>isFloatingPointTy</tt>,
864<tt>isFPOrFPVectorTy</tt> and <tt>isFPOrFPVectorTy</tt> respectively.</li>
Devang Patel0e3da1a2008-10-14 20:03:43 +0000[diff] [blame]865</ul>
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]866
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]867</div>
868
869
870
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]871<!-- *********************************************************************** -->
872<div class="doc_section">
873 <a name="portability">Portability and Supported Platforms</a>
874</div>
875<!-- *********************************************************************** -->
876
877<div class="doc_text">
878
879<p>LLVM is known to work on the following platforms:</p>
880
881<ul>
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame]882<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]883 Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like
884 systems).</li>
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]885<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]886 and 64-bit modes.</li>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]887<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]888<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
889 support is available for native builds with Visual C++).</li>
Chris Lattner9235ce52009-10-16 16:30:58 +0000[diff] [blame]890<li>Sun x86 and AMD64 machines running Solaris 10, OpenSolaris 0906.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]891<li>Alpha-based machines running Debian GNU/Linux.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]892</ul>
893
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]894<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]895to the machine and operating system on which it is built. However, minor
896porting may be required to get LLVM to work on new platforms. We welcome your
897portability patches and reports of successful builds or error messages.</p>
898
899</div>
900
901<!-- *********************************************************************** -->
902<div class="doc_section">
903 <a name="knownproblems">Known Problems</a>
904</div>
905<!-- *********************************************************************** -->
906
907<div class="doc_text">
908
Mikhail Glushenkovf61066a2009-03-01 18:09:47 +0000[diff] [blame]909<p>This section contains significant known problems with the LLVM system,
Chris Lattnerb1ad47c2008-11-10 05:40:34 +0000[diff] [blame]910listed by component. If you run into a problem, please check the <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]911href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
912there isn't already one.</p>
913
Chris Lattner1f8dc512010-03-17 17:25:49 +0000[diff] [blame]914<ul>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]915<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
916using the stock GCC 3.x.x series 'out the box',
Chris Lattnerc09ffd22009-11-03 21:50:09 +0000[diff] [blame]917See: <a href="GettingStarted.html#brokengcc">Broken versions of GCC and other tools</a>.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]918However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
919for x86/x86-64 has been made available from the third party AuroraUX Project
920that has been meticulously tested for bootstrapping LLVM &amp; Clang.</li>
921</ul>
922
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]923</div>
924
925<!-- ======================================================================= -->
926<div class="doc_subsection">
927 <a name="experimental">Experimental features included with this release</a>
928</div>
929
930<div class="doc_text">
931
932<p>The following components of this LLVM release are either untested, known to
933be broken or unreliable, or are in early development. These components should
934not be relied on, and bugs should not be filed against them, but they may be
935useful 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]936components, please contact us on the <a
937href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]938
939<ul>
Wesley Peckbe6dc822010-03-18 14:31:30 +0000[diff] [blame]940<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
941 backends are experimental.</li>
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]942<li><tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000[diff] [blame]943 supported value for this option. The MachO writer is experimental, and
944 works much better in mainline SVN.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]945</ul>
946
947</div>
948
949<!-- ======================================================================= -->
950<div class="doc_subsection">
951 <a name="x86-be">Known problems with the X86 back-end</a>
952</div>
953
954<div class="doc_text">
955
956<ul>
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000[diff] [blame]957 <li>The X86 backend does not yet support
958 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
959 floating point stack</a>. It supports the 'f' and 't' constraints, but not
960 'u'.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]961 <li>The X86 backend generates inefficient floating point code when configured
962 to generate code for systems that don't have SSE2.</li>
Duncan Sands8b4f3772008-06-08 19:38:43 +0000[diff] [blame]963 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswellaea8c752009-03-02 15:28:15 +0000[diff] [blame]964 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]965 runtime currently due to lack of support for the 'u' inline assembly
966 constraint and for X87 floating point inline assembly.</li>
Dan Gohman3882ecb2008-06-08 23:05:11 +0000[diff] [blame]967 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner8f33c262010-04-22 06:28:20 +0000[diff] [blame]968 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman3882ecb2008-06-08 23:05:11 +0000[diff] [blame]969 argument constructs on X86-64 by lowering them manually.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]970</ul>
971
972</div>
973
974<!-- ======================================================================= -->
975<div class="doc_subsection">
976 <a name="ppc-be">Known problems with the PowerPC back-end</a>
977</div>
978
979<div class="doc_text">
980
981<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]982<li>The Linux PPC32/ABI support needs testing for the interpreter and static
983compilation, and lacks support for debug information.</li>
984</ul>
985
986</div>
987
988<!-- ======================================================================= -->
989<div class="doc_subsection">
990 <a name="arm-be">Known problems with the ARM back-end</a>
991</div>
992
993<div class="doc_text">
994
995<ul>
996<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]997processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]998results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswellaea8c752009-03-02 15:28:15 +0000[diff] [blame]999<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1000</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1001</ul>
1002
1003</div>
1004
1005<!-- ======================================================================= -->
1006<div class="doc_subsection">
1007 <a name="sparc-be">Known problems with the SPARC back-end</a>
1008</div>
1009
1010<div class="doc_text">
1011
1012<ul>
John Criswellaea8c752009-03-02 15:28:15 +0000[diff] [blame]1013<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]1014 support the 64-bit SPARC ABI (-m64).</li>
1015</ul>
1016
1017</div>
1018
1019<!-- ======================================================================= -->
1020<div class="doc_subsection">
Bruno Cardoso Lopes62d45d72008-10-25 14:56:26 +0000[diff] [blame]1021 <a name="mips-be">Known problems with the MIPS back-end</a>
1022</div>
1023
1024<div class="doc_text">
1025
1026<ul>
Bruno Cardoso Lopes62d45d72008-10-25 14:56:26 +0000[diff] [blame]1027<li>64-bit MIPS targets are not supported yet.</li>
1028</ul>
1029
1030</div>
1031
1032<!-- ======================================================================= -->
1033<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1034 <a name="alpha-be">Known problems with the Alpha back-end</a>
1035</div>
1036
1037<div class="doc_text">
1038
1039<ul>
1040
1041<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
1042appropriate nops inserted to ensure restartability.</li>
1043
1044</ul>
1045</div>
1046
1047<!-- ======================================================================= -->
1048<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1049 <a name="c-be">Known problems with the C back-end</a>
1050</div>
1051
1052<div class="doc_text">
1053
1054<ul>
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]1055<li><a href="http://llvm.org/PR802">The C backend has only basic support for
1056 inline assembly code</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]1057<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
1058 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greife33c5322009-03-02 12:02:51 +0000[diff] [blame]1059 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandsbd0ad6e2008-02-10 13:40:55 +0000[diff] [blame]1060<li>The C backend does not support all exception handling constructs.</li>
Duncan Sandse6e264c2009-02-25 11:51:54 +0000[diff] [blame]1061<li>The C backend does not support arbitrary precision integers.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1062</ul>
1063
1064</div>
1065
1066
1067<!-- ======================================================================= -->
1068<div class="doc_subsection">
Chris Lattner58b1d0f2010-03-17 04:41:49 +0000[diff] [blame]1069 <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]1070</div>
1071
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1072<div class="doc_text">
1073
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]1074<p>The only major language feature of GCC not supported by llvm-gcc is
1075 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
1076 are only supported on some targets. For example, trampolines are only
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]1077 supported on some targets (these are used when you take the address of a
1078 nested function).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1079
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1080</div>
1081
1082<!-- ======================================================================= -->
1083<div class="doc_subsection">
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000[diff] [blame]1084 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
1085</div>
1086
1087<div class="doc_text">
Gabor Greif1fc8fbc2008-11-04 21:50:59 +0000[diff] [blame]1088<ul>
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000[diff] [blame]1089<li>Fortran support generally works, but there are still several unresolved bugs
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]1090 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
1091 tools/gfortran component for details.</li>
Gabor Greif1fc8fbc2008-11-04 21:50:59 +0000[diff] [blame]1092</ul>
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000[diff] [blame]1093</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1094
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]1095<!-- ======================================================================= -->
1096<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]1097 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]1098</div>
1099
1100<div class="doc_text">
John Criswellaea8c752009-03-02 15:28:15 +0000[diff] [blame]1101The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
1102technology, and problems should be expected.
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]1103<ul>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]1104<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]1105to lack of trampoline support (pointers to nested functions) on other platforms.
1106However, 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]1107which does support trampolines.</li>
1108<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]1109This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
1110exception handling, which is used internally by the compiler.
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]1111Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
Duncan Sands2dbc2e82008-10-13 17:27:23 +0000[diff] [blame]1112<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
1113and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sandsf73473e2009-02-25 11:59:06 +0000[diff] [blame]1114(c380004 also fails with gcc-4.2 mainline).
1115If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
1116causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sandsc2a29a02009-03-02 16:35:57 +0000[diff] [blame]1117<li>Some GCC specific Ada tests continue to crash the compiler.</li>
Chris Lattner0b6ea7a2009-10-13 17:48:04 +0000[diff] [blame]1118<li>The <tt>-E</tt> binder option (exception backtraces)
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]1119<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]1120crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]1121<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
1122or finish at a non-byte offset</a> in a record. Workaround: do not pack records
1123or use representation clauses that result in a field of a non-discrete type
1124starting or finishing in the middle of a byte.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]1125<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
1126'main' as generated by the Ada binder to be invalid</a>.
1127Workaround: hand edit the file to use pointers for <tt>argv</tt> and
1128<tt>envp</tt> rather than integers.</li>
1129<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
1130ignored</a>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]1131</ul>
1132</div>
1133
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1134<!-- *********************************************************************** -->
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