Gitiles
Code Review Sign In
gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / eedf6fe58152e95a78d5924694d39ffa264dbb08 / . / docs / ReleaseNotes.html
blob: 430d95eb947aa1bcf0dfc22acc3c653a8c2a7e06 [file] [log] [blame]
Anton Korobeynikov0d176912008-06-08 10:23:46 +0000[diff] [blame]1
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]2<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
3 "http://www.w3.org/TR/html4/strict.dtd">
4<html>
5<head>
Reid Spencer6454ed32004-11-18 18:38:58 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]7 <link rel="stylesheet" href="llvm.css" type="text/css">
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]8 <title>LLVM 2.3 Release Notes</title>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]9</head>
10<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]11
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]12<div class="doc_title">LLVM 2.3 Release Notes</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]13
14<ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]15 <li><a href="#intro">Introduction</a></li>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]16 <li><a href="#changes">Major Changes and Sub-project Status</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#whatsnew">What's New?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +0000[diff] [blame]18 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]19 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]20 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]21 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]22</ol>
23
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]24<div class="doc_author">
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]25 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]26</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]27
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]28<!-- Done through Week-of-Mon-20080324.txt -->
29
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]30<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]31<div class="doc_section">
32 <a name="intro">Introduction</a>
33</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]34<!-- *********************************************************************** -->
35
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]36<div class="doc_text">
37
38<p>This document contains the release notes for the LLVM compiler
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]39infrastructure, release 2.3. Here we describe the status of LLVM, including
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]40major improvements from the previous release and any known problems. All LLVM
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]41releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]42releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]43
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]44<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]45release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]46web site</a>. If you have questions or comments, the <a
47href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]48list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]49
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]50<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]51main LLVM web page, this document applies to the <i>next</i> release, not the
52current one. To see the release notes for a specific releases, please see the
53<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]54
55</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]56
57<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]58<div class="doc_section">
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]59 <a name="changes">Major Changes and Sub-project Status</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]60</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]61<!-- *********************************************************************** -->
62
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]63<div class="doc_text">
64
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]65<p>This is the fourteenth public release of the LLVM Compiler Infrastructure.
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]66It includes a large number of features and refinements from LLVM 2.2.</p>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]67
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]68</div>
69
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]70<!-- Unfinished features in 2.3:
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]71 Machine LICM
72 Machine Sinking
73 LegalizeDAGTypes
74 -->
75
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]76<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]77<div class="doc_subsection">
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]78<a name="changes">Major Changes in LLVM 2.3</a>
Chris Lattnerb4c68cd2008-02-10 07:04:35 +0000[diff] [blame]79</div>
80
81<div class="doc_text">
82
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]83<p>LLVM 2.3 no longer supports llvm-gcc 4.0, it has been replaced with
84 llvm-gcc 4.2.</p>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]85
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]86<p>LLVM 2.3 no longer includes the <tt>llvm-upgrade</tt> tool. It was useful
87 for upgrading LLVM 1.9 files to LLVM 2.x syntax, but you can always use a
88 previous LLVM release to do this. One nice impact of this is that the LLVM
89 regression test suite no longer depends on llvm-upgrade, which makes it run
90 faster.</p>
91
92<p>The <tt>llvm2cpp</tt> tool has been folded into llc, use
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]93 <tt>llc -march=cpp</tt> instead of <tt>llvm2cpp</tt>.</p>
94
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]95<p>LLVM API Changes:</p>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]96
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]97<ul>
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]98<li>Several core LLVM IR classes have migrated to use the
99 '<tt>FOOCLASS::Create(...)</tt>' pattern instead of '<tt>new
100 FOOCLASS(...)</tt>' (e.g. where FOOCLASS=<tt>BasicBlock</tt>). We hope to
101 standardize on <tt>FOOCLASS::Create</tt> for all IR classes in the future,
102 but not all of them have been moved over yet.</li>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]103<li>LLVM 2.3 renames the LLVMBuilder and LLVMFoldingBuilder classes to
104 IRBuilder.</li>
105<li>MRegisterInfo was renamed to TargetRegisterInfo.</li>
106<li>The MappedFile class is gone, please use MemoryBuffer instead.</li>
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]107<li>The '<tt>-enable-eh</tt>' flag to llc has been removed. Now code should
108 encode whether it is safe to omit unwind information for a function by
109 tagging the Function object with the '<tt>nounwind</tt>' attribute.</li>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]110
111</ul>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]112</div>
113
114<!--=========================================================================-->
115<div class="doc_subsection">
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]116<a name="otherprojects">Other LLVM Sub-Projects</a>
117</div>
118
119<div class="doc_text">
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]120<p>
121The core LLVM 2.3 distribution currently consists of code from the core LLVM
122repository (which roughly contains the LLVM optimizer, code generators and
123supporting tools) and the llvm-gcc repository. In addition to this code, the
124LLVM Project includes other sub-projects that are in development. The two which
125are the most actively developed are the new <a href="#vmkit">vmkit Project</a>
126and the <a href="#clang">Clang Project</a>.
127</p>
128</div>
129
130<!--=========================================================================-->
131<div class="doc_subsubsection">
132<a name="vmkit">vmkit</a>
133</div>
134
135<div class="doc_text">
136<p>
137The "vmkit" project is a new addition to the LLVM family. It is an
138implementation of a JVM and a CLI Virtual Machines (Microsoft .NET is an
139implementation of the CLI) using the Just-In-Time compiler of LLVM.</p>
140
141<p>The JVM, called JnJVM, executes real-world applications such as Apache
142projects (e.g. Felix and Tomcat) and the SpecJVM98 benchmark. It uses the GNU
143Classpath project for the base classes. The CLI implementation, called N3, is
144its in early stages but can execute simple applications and the "pnetmark"
145benchmark. It uses the pnetlib project as its core library.</p>
146
147<p>The 'vmkit' VMs compare in performance with industrial and top open-source
148VMs on scientific applications. Besides the JIT, the VMs use many features of
149the LLVM framework, including the standard set of optimizations, atomic
150operations, custom function provider and memory manager for JITed methods, and
151specific virtual machine optimizations. vmkit is not an official part of LLVM
1522.3 release. It is publicly available under the LLVM license and can be
153downloaded from:
154</p>
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]155
156<p>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]157<tt>svn co http://llvm.org/svn/llvm-project/vmkit/trunk vmkit</tt>
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]158</p>
159
160</div>
161
162<!--=========================================================================-->
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]163<div class="doc_subsubsection">
164<a name="clang">Clang</a>
165</div>
166
167<div class="doc_text">
168
169<p>The <a href="http://clang.llvm.org/">Clang project</a> is an effort to build
170a set of new 'LLVM native' front-end technologies for the LLVM optimizer
171and code generator. Clang is continuing to make major strides forward in all
172areas. Its C and Objective-C parsing support is very solid, and the code
173generation support is far enough along to build many C applications. While not
174yet production quality, it is progressing very nicely. In addition, C++
175front-end work has started to make significant progress.</p>
176
177<p>At this point, Clang is most useful if you are interested in source-to-source
178transformations (such as refactoring) and other source-level tools for C and
179Objective-C. Clang now also includes tools for turning C code into pretty HTML,
180and includes a new <a href="http://clang.llvm.org/StaticAnalysis.html">static
181analysis tool</a> in development. This tool is automatically focused on finding
182bugs in C and Objective-C code.</p>
183
184</div>
185
186
187<!-- *********************************************************************** -->
188<div class="doc_section">
189 <a name="whatsnew">What's New?</a>
190</div>
191<!-- *********************************************************************** -->
192
193<!--=========================================================================-->
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]194<div class="doc_subsection">
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]195<a name="majorfeatures">Major New Features</a>
196</div>
197
198<div class="doc_text">
199
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]200<p>LLVM 2.3 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]201
202<ul>
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]203<li><p>The biggest change in LLVM 2.3 is Multiple Return Value (MRV) support.
204 MRVs allow LLVM IR to directly represent functions that return multiple
205 values without having to pass them "by reference" in the LLVM IR. This
206 allows a front-end to generate more efficient code, as MRVs are generally
207 returned in registers if a target supports them. See the <a
208 href="LangRef.html#i_getresult">LLVM IR Reference</a> for more details.</p>
209
210 <p>MRVs are fully supported in the LLVM IR, but are not yet fully supported in
211 on all targets. However, it is generally safe to return up to 2 values from
212 a function: most targets should be able to handle at least that. MRV
213 support is a critical requirement for X86-64 ABI support, as X86-64 requires
214 the ability to return multiple registers from functions, and we use MRVs to
215 accomplish this in a direct way.</p></li>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]216
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]217<li><p>LLVM 2.3 includes a complete reimplementation of the "<tt>llvmc</tt>"
218 tool. It is designed to overcome several problems with the original
219 <tt>llvmc</tt> and to provide a superset of the features of the
220 '<tt>gcc</tt>' driver.</p>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]221
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]222<p>The main features of <tt>llvmc2</tt> are:
223 <ul>
224 <li>Extended handling of command line options and smart rules for
225 dispatching them to different tools.</li>
226 <li>Flexible (and extensible) rules for defining different tools.</li>
227 <li>The different intermediate steps performed by tools are represented
228 as edges in the abstract graph.</li>
229 <li>The 'language' for driver behavior definition is tablegen and thus
230 it's relatively easy to add new features.</li>
231 <li>The definition of driver is transformed into set of C++ classes, thus
232 no runtime interpretation is needed.</li>
233 </ul></p>
234 </li>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]235
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]236<li><p>LLVM 2.3 includes a completely rewritten interface for <a
237 href="LinkTimeOptimization.html">Link Time Optimization</a>. This interface
238 is written in C, which allows for easier integration with C code bases, and
239 incorporates improvements we learned about from the first incarnation of the
240 interface.</p></li>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]241
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]242<li><p>The <a href="tutorial/LangImpl1.html">Kaleidoscope tutorial</a> now
243 includes a "port" of the tutorial that <a
244 href="tutorial/OCamlLangImpl1.html">uses the Ocaml bindings</a> to implement
245 the Kaleidoscope language.</p></li>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]246
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]247</ul>
248
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]249</div>
250
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]251
252<!--=========================================================================-->
253<div class="doc_subsection">
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]254<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]255</div>
256
257<div class="doc_text">
258
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]259<p>LLVM 2.3 fully supports the llvm-gcc 4.2 front-end.</p>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]260
261<p>llvm-gcc 4.2 includes numerous fixes to better support the Objective-C
262front-end. Objective-C now works very well on Mac OS/X.</p>
263
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]264<p>Fortran EQUIVALENCEs are now supported by the gfortran front-end.</p>
265
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]266<p>llvm-gcc 4.2 includes many other fixes which improve conformance with the
267relevant parts of the GCC testsuite.</p>
268
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]269</div>
270
271
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]272<!--=========================================================================-->
273<div class="doc_subsection">
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]274<a name="coreimprovements">LLVM Core Improvements</a>
275</div>
276
277<div class="doc_text">
278<p>New features include:
279</p>
280
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]281
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]282Common linkage?
283
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]284Atomic operation support, Alpha, X86, X86-64, PowerPC. "__sync_synchronize",
Anton Korobeynikov0d176912008-06-08 10:23:46 +0000[diff] [blame]285"__sync_val_compare_and_swap", etc
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]286
287<ul>
Gordon Henriksen1494bcc2008-06-05 12:51:50 +0000[diff] [blame]288<li>The C and Ocaml bindings have received additional improvements. The
289bindings now cover pass managers, several transformation passes, iteration
290over the LLVM IR, target data, and parameter attribute lists.</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]291</ul>
292
293</div>
294
295<!--=========================================================================-->
296<div class="doc_subsection">
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]297<a name="optimizer">Optimizer Improvements</a>
298</div>
299
300<div class="doc_text">
301
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]302<p>In addition to a huge array of bug fixes and minor performance tweaks, the
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]303LLVM 2.3 optimizers support a few major enhancements:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]304
305<ul>
306
Devang Patel83a15d72008-06-05 21:44:00 +0000[diff] [blame]307<li>Loop index set splitting on by default.<p>
308This transformation hoists conditions from loop bodies and reduces loop's
309iteration space to improve performance. For example, <p>
310<pre>
Chris Lattnerc4e6b372008-06-08 20:25:30 +0000[diff] [blame]311for (i = LB; i &lt; UB; ++i)
312 if (i &lt;= NV)
Devang Patel83a15d72008-06-05 21:44:00 +0000[diff] [blame]313 LOOP_BODY
314</pre>
315is transformed into
316<pre>
317NUB = min(NV+1, UB)
Chris Lattnerc4e6b372008-06-08 20:25:30 +0000[diff] [blame]318for (i = LB; i &lt; NUB; ++i)
Devang Patel83a15d72008-06-05 21:44:00 +0000[diff] [blame]319 LOOP_BODY
320</pre>
321</li>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]322
Gordon Henriksen7e59b8a2008-06-08 22:05:11 +0000[diff] [blame]323<li>LLVM includes a new <tt>memcpy</tt> optimization pass which removes
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]324dead <tt>memcpy</tt> calls, unneeded copies of aggregates, and performs
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]325return slot optimization. The LLVM optimizer now notices long sequences of
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]326consecutive stores and merges them into <tt>memcpy</tt>'s where profitable.</li>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]327
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]328<li>Alignment detection for vector memory references and for <tt>memcpy</tt> and
329<tt>memset</tt> is now more aggressive.</li>
Owen Anderson30073ff2008-06-06 16:23:15 +0000[diff] [blame]330
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]331<li>The aggressive dead code elimination (ADCE) optimization has been rewritten
332to make it both faster and safer in the presence of code containing infinite
333loops. Some of its prior functionality has been factored out into the loop
334deletion pass, which <em>is</em> safe for infinite loops.</li>
335
336<li>Several optimizations have been sped up, leading to faster code generation
337 with the same code quality.</li>
338
339<li>The 'SimplifyLibCalls' pass, which optimizes calls to libc and libm
340 functions for C-based languages, has been rewritten to be a FunctionPass
341 instead a ModulePass. This allows it to be run more often and to be
342 included at -O1 in llvm-gcc. It was also extended to include more
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]343 optimizations and several corner case bugs were fixed.</li>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]344
Duncan Sands47eff2b2008-06-08 19:38:43 +0000[diff] [blame]345<li>LLVM now includes a simple 'Jump Threading' pass, which attempts to simplify
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]346 conditional branches using information about predecessor blocks, simplifying
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]347 the control flow graph. This pass is pretty basic at this point, but
348 catches some important cases and provides a foundation to build on.</li>
349
350<li>Several corner case bugs which could lead to deleting volatile memory
351 accesses have been fixed.</li>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]352</ul>
353
354</div>
355
356<!--=========================================================================-->
357<div class="doc_subsection">
358<a name="codegen">Code Generator Improvements</a>
359</div>
360
361<div class="doc_text">
362
363<p>We put a significant amount of work into the code generator infrastructure,
364which allows us to implement more aggressive algorithms and make it run
365faster:</p>
366
367<ul>
368<li>MemOperand in the code generator: describe me!.</li>
369
370<li>The target-independent code generator infrastructure now uses LLVM's APInt
371 class to handle integer values, which allows it to support integer types
372 larger than 64 bits. Note that support for such types is also dependent on
373 target-specific support. Use of APInt is also a step toward support for
374 non-power-of-2 integer sizes.</li>
375
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]376<li>LLVM 2.3 includes several compile time speedups for code with large basic
Dan Gohmaneedf6fe2008-06-08 22:44:43 +0000[diff] [blame^]377 blocks, particularly in the instruction selection phase, register
378 allocation, scheduling, and tail merging/jump threading.</li>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]379
380<li>Several improvements which make llc's <tt>--view-sunit-dags</tt>
381 visualization of scheduling dependency graphs easier to understand.</li>
382
383<li>The code generator allows targets to write patterns that generate subreg
384 references directly in .td files now.</li>
385
386<li><tt>memcpy</tt> lowering in the backend is more aggressive, particularly for
387 <tt>memcpy</tt> calls introduced by the code generator when handling
388 pass-by-value structure argument copies.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]389
390<li>Inline assembly with multiple register results now returns those results
391 directly in the appropriate registers, rather than going through memory.
392 Inline assembly that uses constraints like "ir" with immediates now use the
393 'i' form when possible instead of always loading the value in a register.
394 This saves an instruction and reduces register use.</li>
395
396<li>Added support for PIC/GOT style tail calls on x86/32 and initial support
397 for tail calls on PowerPC 32 (it may also work on ppc64 but not
398 thoroughly tested).</li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]399</ul>
400
401</div>
402
403
404<!--=========================================================================-->
405<div class="doc_subsection">
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]406<a name="x86specific">X86/X86-64 Specific Improvements</a>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]407</div>
Chris Lattner60893e52007-05-18 06:33:02 +0000[diff] [blame]408
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]409<div class="doc_text">
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]410<p>New target-specific features include:
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]411</p>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]412
413<ul>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]414<li>llvm-gcc's X86-64 ABI conformance is far improved, particularly in the
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]415 area of passing and returning structures by value. llvm-gcc compiled code
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]416 now interoperates very well on X86-64 systems with other compilers.</li>
417
Duncan Sands47eff2b2008-06-08 19:38:43 +0000[diff] [blame]418<li>Support for Win64 was added. This includes code generation itself, JIT
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]419 support and necessary changes to llvm-gcc.</li>
420
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]421<li>The LLVM X86 backend now supports the support SSE 4.1 instruction set, and
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]422 the llvm-gcc 4.2 front-end supports the SSE 4.1 compiler builtins. Various
423 generic vector operations (insert/extract/shuffle) are much more efficient
424 when SSE 4.1 is enabled. The JIT automatically takes advantage of these
425 instructions, but llvm-gcc must be explicitly told to use them, e.g. with
426 <tt>-march=penryn</tt>.</li>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]427
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]428<li>The X86 backend now does a number of optimizations that aim to avoid
429 converting numbers back and forth from SSE registers to the X87 floating
430 point stack.</li>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]431
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]432<li>The X86 backend supports stack realignment, which is particularly useful for
433 vector code on OS's without 16-byte aligned stacks.</li>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]434
435<li>The X86 backend now supports the "sseregparm" options in GCC, which allow
436 functions to be tagged as passing floating point values in SSE
437 registers.</li>
438
439<li>Trampolines (taking the address of a nested function) now work on
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]440 Linux/X86-64.</li>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]441
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]442<li><tt>__builtin_prefetch</tt> is now compiled into the appropriate prefetch
443 instructions instead of being ignored.</li>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]444
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]445<li>128-bit integers are now supported on X86-64 targets.</li>
Dan Gohman4e16d402008-06-05 16:15:39 +0000[diff] [blame]446
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]447<li>The register allocator can now rematerialize PIC-base computations.</li>
448
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]449<li>The "t" and "f" inline assembly constraints for the X87 floating point stack
450 now work. However, the "u" constraint is still not fully supported.</li>
451
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000[diff] [blame]452</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]453
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000[diff] [blame]454</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]455
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]456<!--=========================================================================-->
457<div class="doc_subsection">
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]458<a name="targetspecific">Other Target Specific Improvements</a>
459</div>
460
461<div class="doc_text">
462<p>New target-specific features include:
463</p>
464
465<ul>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]466<li>The LLVM C backend now supports vector code.</li>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]467</ul>
468
469</div>
470
471
472
473<!--=========================================================================-->
474<div class="doc_subsection">
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]475<a name="otherimprovements">Other Improvements</a>
476</div>
477
478<div class="doc_text">
479<p>New features include:
480</p>
481
482<ul>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]483<li>LLVM now builds with GCC 4.3.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]484<li>Bugpoint now supports running custom scripts (with the <tt>-run-custom</tt>
485 option) to determine how to execute the command and whether it is making
486 forward process.</li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]487</ul>
488
489</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]490
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]491<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]492<div class="doc_section">
493 <a name="portability">Portability and Supported Platforms</a>
494</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]495<!-- *********************************************************************** -->
496
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]497<div class="doc_text">
498
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]499<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]500
501<ul>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]502<li>Intel and AMD machines (IA32) running Red Hat Linux, Fedora Core and FreeBSD
Reid Spencer00812e22005-05-17 02:47:27 +0000[diff] [blame]503 (and probably other unix-like systems).</li>
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]504<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit and
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]505 64-bit modes.</li>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]506<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]507<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
508 support is available for native builds with Visual C++).</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]509<li>Sun UltraSPARC workstations running Solaris 10.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]510<li>Alpha-based machines running Debian GNU/Linux.</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]511<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]512</ul>
513
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]514<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]515to the machine and operating system on which it is built. However, minor
516porting may be required to get LLVM to work on new platforms. We welcome your
517portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]518
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]519</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]520
521<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]522<div class="doc_section">
523 <a name="knownproblems">Known Problems</a>
524</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]525<!-- *********************************************************************** -->
526
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]527<div class="doc_text">
528
529<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]530component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]531sections. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]532href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]533there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]534
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]535</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]536
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]537<!-- ======================================================================= -->
538<div class="doc_subsection">
539 <a name="experimental">Experimental features included with this release</a>
540</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]541
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]542<div class="doc_text">
543
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]544<p>The following components of this LLVM release are either untested, known to
545be broken or unreliable, or are in early development. These components should
546not be relied on, and bugs should not be filed against them, but they may be
547useful to some people. In particular, if you would like to work on one of these
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]548components, please contact us on the <a
549href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]550
551<ul>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]552<li>The MSIL, IA64, Alpha, SPU, and MIPS backends are experimental.</li>
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]553<li>The llc "<tt>-filetype=asm</tt>" (the default) is the only supported
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]554 value for this option.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]555</ul>
556
557</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]558
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]559<!-- ======================================================================= -->
560<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]561 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]562</div>
563
564<div class="doc_text">
565
566<ul>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]567 <li>The X86 backend does not yet support
568 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
569 floating point stack</a>. It supports the 'f' and 't' constraints, but not
570 'u'.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]571 <li>The X86 backend generates inefficient floating point code when configured
572 to generate code for systems that don't have SSE2.</li>
Duncan Sands47eff2b2008-06-08 19:38:43 +0000[diff] [blame]573 <li>Win64 code generation wasn't widely tested. Everything should work, but we
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]574 expect small issues to happen. Also, llvm-gcc cannot build mingw64 runtime
575 currently due
576 to <a href="http://llvm.org/PR2255">several</a>
577 <a href="http://llvm.org/PR2257">bugs</a> in FP stackifier
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]578</ul>
579
580</div>
581
582<!-- ======================================================================= -->
583<div class="doc_subsection">
584 <a name="ppc-be">Known problems with the PowerPC back-end</a>
585</div>
586
587<div class="doc_text">
588
589<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000[diff] [blame]590<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]591compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]592</ul>
593
594</div>
595
596<!-- ======================================================================= -->
597<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]598 <a name="arm-be">Known problems with the ARM back-end</a>
599</div>
600
601<div class="doc_text">
602
603<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]604<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000[diff] [blame]605processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]606results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]607<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
608</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]609<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly
610 execute
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]611programs compiled with LLVM. Please use more recent versions of QEMU.</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]612</ul>
613
614</div>
615
616<!-- ======================================================================= -->
617<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]618 <a name="sparc-be">Known problems with the SPARC back-end</a>
619</div>
620
621<div class="doc_text">
622
623<ul>
624<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
625 support the 64-bit SPARC ABI (-m64).</li>
626</ul>
627
628</div>
629
630<!-- ======================================================================= -->
631<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]632 <a name="alpha-be">Known problems with the Alpha back-end</a>
633</div>
634
635<div class="doc_text">
636
637<ul>
638
639<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
640appropriate nops inserted to ensure restartability.</li>
641
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]642</ul>
643</div>
644
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]645<!-- ======================================================================= -->
646<div class="doc_subsection">
647 <a name="ia64-be">Known problems with the IA64 back-end</a>
648</div>
649
650<div class="doc_text">
651
652<ul>
653
654<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
655made where the argument is not 16-byte aligned, as required on IA64. (Strictly
656speaking this is not a bug in the IA64 back-end; it will also be encountered
657when building C++ programs using the C back-end.)</li>
658
659<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
660ABI compliant layout of v-tables</a>. In particular, it just stores function
661pointers instead of function descriptors in the vtable. This bug prevents
662mixing C++ code compiled with LLVM with C++ objects compiled by other C++
663compilers.</li>
664
665<li>There are a few ABI violations which will lead to problems when mixing LLVM
666output with code built with other compilers, particularly for floating-point
667programs.</li>
668
Duncan Sands47eff2b2008-06-08 19:38:43 +0000[diff] [blame]669<li>Defining vararg functions is not supported (but calling them is OK).</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]670
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]671<li>The Itanium backend has bitrotted somewhat.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]672</ul>
673
674</div>
675
676<!-- ======================================================================= -->
677<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]678 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]679</div>
680
681<div class="doc_text">
682
683<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]684<li><a href="http://llvm.org/PR802">The C backend has only basic support for
685 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000[diff] [blame]686<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
687 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]688 C++ code compiled with llc or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]689<li>The C backend does not support all exception handling constructs.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]690</ul>
691
692</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]693
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]694
695<!-- ======================================================================= -->
696<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]697 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]698</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]699
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]700<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]701<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]702
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]703<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]704
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]705<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
706Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]707llvmdev mailing list if you are interested.</p>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]708
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]709<p>The only major language feature of GCC not supported by llvm-gcc is
710 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
711 are only supported on some targets. For example, trampolines are only
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]712 supported on some targets (these are used when you take the address of a
713 nested function).</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]714
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]715<p>If you run into GCC extensions which are not supported, please let us know.
716</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]717
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]718</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]719
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]720<!-- ======================================================================= -->
721<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]722 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]723</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]724
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]725<div class="doc_text">
726
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]727<p>The C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]728tested and works for a number of non-trivial programs, including LLVM
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]729itself, Qt, Mozilla, etc.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]730
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]731<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]732<li>Exception handling works well on the X86 and PowerPC targets, including
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]733X86-64 darwin. This works when linking to a libstdc++ compiled by GCC. It is
734supported on X86-64 linux, but that is disabled by default in this release.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]735</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]736
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]737</div>
738
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]739
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]740<!-- ======================================================================= -->
741<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]742 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]743</div>
744
745<div class="doc_text">
746The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
747technology and problems should be expected.
748<ul>
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]749<li>The Ada front-end currently only builds on X86-32. This is mainly due
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]750to lack of trampoline support (pointers to nested functions) on other platforms,
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]751however it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]752which does support trampolines.</li>
753<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
754Workaround: configure with --disable-bootstrap.</li>
755<li>The c380004 and <a href="http://llvm.org/PR2010">c393010</a> ACATS tests
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]756fail (c380004 also fails with gcc-4.2 mainline). When built at -O3, the
757<a href="http://llvm.org/PR2421">cxg2021</a> ACATS test also fails.</li>
758<li>Some gcc specific Ada tests continue to crash the compiler. The testsuite
759reports most tests as having failed even though they pass.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]760<li>The -E binder option (exception backtraces)
761<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
762crashing if an exception is raised. Workaround: do not use -E.</li>
763<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
764or finish at a non-byte offset</a> in a record. Workaround: do not pack records
765or use representation clauses that result in a field of a non-discrete type
766starting or finishing in the middle of a byte.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]767<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
768'main' as generated by the Ada binder to be invalid</a>.
769Workaround: hand edit the file to use pointers for <tt>argv</tt> and
770<tt>envp</tt> rather than integers.</li>
771<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
772ignored</a>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]773</ul>
774</div>
775
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]776<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]777<div class="doc_section">
778 <a name="additionalinfo">Additional Information</a>
779</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]780<!-- *********************************************************************** -->
781
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]782<div class="doc_text">
783
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]784<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]785href="http://llvm.org">LLVM web page</a>, in particular in the <a
786href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]787contains versions of the API documentation which is up-to-date with the
788Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]789You can access versions of these documents specific to this release by going
790into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]791
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]792<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]793us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]794lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]795
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]796</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]797
798<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]799
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]800<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]801<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]802 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]803 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
804 <a href="http://validator.w3.org/check/referer"><img
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]805 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]806
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]807 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]808 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]809</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]810
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]811</body>
812</html>