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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / c463b2746670b90575fc8f388a55f2a6867db905 / . / docs / ReleaseNotes.html
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Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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3<html>
4<head>
Reid Spencer6454ed32004-11-18 18:38:58 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]6 <link rel="stylesheet" href="llvm.css" type="text/css">
John Criswell98391ce2005-05-18 20:28:46 +0000[diff] [blame]7 <title>LLVM 1.6 Release Notes</title>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]8</head>
9<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]10
John Criswell98391ce2005-05-18 20:28:46 +0000[diff] [blame]11<div class="doc_title">LLVM 1.6 Release Notes</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]12
13<ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]14 <li><a href="#intro">Introduction</a></li>
15 <li><a href="#whatsnew">What's New?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +0000[diff] [blame]16 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]18 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]19 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]20</ol>
21
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]22<div class="doc_author">
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]23 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]24</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]25
26<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]27<div class="doc_section">
28 <a name="intro">Introduction</a>
29</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]30<!-- *********************************************************************** -->
31
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]32<div class="doc_text">
33
34<p>This document contains the release notes for the LLVM compiler
John Criswell98391ce2005-05-18 20:28:46 +0000[diff] [blame]35infrastructure, release 1.6. Here we describe the status of LLVM, including any
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]36known problems and major improvements from the previous release. The most
37up-to-date version of this document can be found on the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]38href="http://llvm.org/releases/1.6/">LLVM 1.6 web site</a>. If you are
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]39not reading this on the LLVM web pages, you should probably go there because
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]40this document may be updated after the release.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]41
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]42<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]43release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]44web site</a>. If you have questions or comments, the <a
45href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]46list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]47
Chris Lattner78bf32b2004-12-09 22:22:58 +0000[diff] [blame]48<p>Note that if you are reading this file from CVS or the main LLVM web page,
49this document applies to the <i>next</i> release, not the current one. To see
50the release notes for the current or previous releases, see the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]51href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]52
53</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]54
55<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]56<div class="doc_section">
57 <a name="whatsnew">What's New?</a>
58</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]59<!-- *********************************************************************** -->
60
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]61<div class="doc_text">
62
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]63<p>This is the seventh public release of the LLVM Compiler Infrastructure. This
64release incorporates a large number of enhancements and additions (primarily in
65the code generator), which combine to improve the quality of the code generated
66by LLVM by up to 30% in some cases. This release is also the first release to
67have first-class support for Mac OS/X: all of the major bugs have been shaken
68out and it is now as well supported as Linux on X86.</p>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]69
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]70</div>
71
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]72<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]73<div class="doc_subsection">
John Criswell98391ce2005-05-18 20:28:46 +0000[diff] [blame]74<a name="newfeatures">New Features in LLVM 1.6</a>
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]75</div>
Brian Gaeke6b31beb2004-01-16 21:55:04 +0000[diff] [blame]76
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]77<!--_________________________________________________________________________-->
78<div class="doc_subsubsection"><a name="iselgen">Instruction Selector
79Generation from Target Description</a></div>
80
81<div class="doc_text">
82<p>LLVM now includes support for auto-generating large portions of the
83instruction selectors from target descriptions. This allows us to
84write patterns in the target .td file, instead of writing lots of
85nasty C++ code. Most of the PowerPC instruction selector is now
86generated from the PowerPC target description files and other targets
87are adding support that will be live for LLVM 1.7.</p>
88
89<p>For example, here are some patterns used by the PowerPC backend. A
90floating-point multiply then subtract instruction (FMSUBS):</p>
91
92<div class="doc_code"><p>
93<tt>(set F4RC:$FRT, (fsub (fmul F4RC:$FRA, F4RC:$FRC), F4RC:$FRB))</tt>
94</p></div>
95
96<p>Exclusive-or by 16-bit immediate (XORI):</p>
97
98<div class="doc_code"><p>
99<tt>(set GPRC:$dst, (xor GPRC:$src1, immZExt16:$src2))</tt>
100</p></div>
101
102<p>Exclusive-or by 16-bit immediate shifted right 16-bits (XORIS):</p>
103
104<div class="doc_code"><p>
105<tt>(set GPRC:$dst, (xor GPRC:$src1, imm16Shifted:$src2))</tt>
106</p></div>
107
108<p>With these definitions, we teach the code generator how to combine these two
109instructions to xor an abitrary 32-bit immediate with the following
110definition. The first line specifies what to match (a xor with an arbitrary
111immediate) the second line specifies what to produce:</p>
112
113<div class="doc_code"><p>
114<pre>def : Pat<(xor GPRC:$in, imm:$imm),
115 (XORIS (XORI GPRC:$in, (LO16 imm:$imm)), (HI16 imm:$imm))>;
116</pre>
117</p></div>
118
119</div>
120
121<!--_________________________________________________________________________-->
122<div class="doc_subsubsection"><a name="sched">Instruction Scheduling
123Support</a></div>
124
125<div class="doc_text">
126
127<p>Instruction selectors using the refined <a
128href="CodeGenerator.html#instselect">instruction selection framework</a> can now
129use a simple pre-pass scheduler included with LLVM 1.6. This scheduler is
130currently simple (cannot be configured much by the targets), but will be
131extended in the future.</p>
132</div>
133
134<!--_________________________________________________________________________-->
135<div class="doc_subsubsection"><a name="subtarget">Code Generator Subtarget
136Support</a></div>
137
138<div class="doc_text">
139<p>It is now straight-forward to parameterize a target implementation, and
140provide a mapping from CPU names to sets of target parameters. LLC now supports
141a <tt>-mcpu=cpu</tt> option that lets you choose a subtarget by CPU name: use
142"<tt>llvm-as &lt; /dev/null | llc -march=XXX -mcpu=help</tt>" to get a list of
143supported CPUs for target "XXX". It also provides a
144<tt>-mattr=+attr1,-attr2</tt> option that can be used to control individual
145features of a target (the previous command will list available features as
146well).</p>
147
148<p>This functionality is nice when you want tell LLC something like "compile to
149code that is specialized for the PowerPC G5, but doesn't use altivec code. In
150this case, using "<tt>llc -march=ppc32 -mcpu=g5 -mattr=-altivec</tt>".</p>
151
152</div>
153
154<!--_________________________________________________________________________-->
155<div class="doc_subsubsection"><a name="jitlock">Other New Features</a></div>
156
Chris Lattnerebc8c7d2005-05-18 22:23:56 +0000[diff] [blame]157<div class="doc_text">
Reid Spencerfce2ddc2005-07-12 16:36:24 +0000[diff] [blame]158<ol>
159 <li>The JIT now uses mutexes to protect its internal data structures. This
160 allows multi-threaded programs to be run from the JIT or interpreter without
161 corruption of the internal data structures. See
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]162 <a href="http://llvm.org/PR418">PR418</a> and
163 <a href="http://llvm.org/PR540">PR540</a> for the details.
Reid Spencerfce2ddc2005-07-12 16:36:24 +0000[diff] [blame]164 </li>
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]165 <li>LLVM on Win32 <a href="http://llvm.org/PR614">no longer requires sed,
166 flex, or bison when compiling with Visual C++</a>.</li>
167 <li>The llvm-test suite can now use the NAG Fortran to C compiler to compile
168 SPEC FP programs if available (allowing us to test all of SPEC'95 &amp;
169 2000).</li>
170 <li>When bugpoint is grinding away and the user hits ctrl-C, it now
171 gracefully stops and gives what it has reduced so far, instead of
172 giving up completely. In addition, <a href="http://llvm.org/PR576">the JIT
173 debugging mode of bugpoint is much faster</a>.</li>
174 <li>LLVM now includes Xcode project files in the llvm/Xcode directory.</li>
175 <li>LLVM now supports Mac OS/X on Intel.</li>
176 <li>LLVM now builds cleanly with GCC 4.1.</li>
Reid Spencerfce2ddc2005-07-12 16:36:24 +0000[diff] [blame]177</ol>
Chris Lattnerebc8c7d2005-05-18 22:23:56 +0000[diff] [blame]178</div>
179
Brian Gaeke6b31beb2004-01-16 21:55:04 +0000[diff] [blame]180<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]181<div class="doc_subsection">
John Criswell98391ce2005-05-18 20:28:46 +0000[diff] [blame]182<a name="codequality">Code Quality Improvements in LLVM 1.6</a>
Chris Lattneraab56d42004-05-23 20:42:08 +0000[diff] [blame]183</div>
Chris Lattner89ca2b82003-10-27 17:06:39 +0000[diff] [blame]184
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]185<div class="doc_text">
186<ol>
187 <li>The <tt>-globalopt</tt> pass can now statically evaluate C++ static
188 constructors when they are simple enough. For example, it can
189 now statically initialize "<tt>struct X { int a; X() : a(4) {} } g;</tt>".
190 </li>
191 <li>The Loop Strength Reduction pass has been completely rewritten, is far
192 more aggressive, and is turned on by default in the RISC targets. On PPC,
193 we find that it often speeds up programs from 10-40% depending on the
194 program.</li>
195 <li>The code produced when exception handling is enabled is far more
196 efficient in some cases, particularly on Mac OS/X.</li>
197</ol>
198</div>
199
200
Chris Lattnerbf307012005-05-16 16:56:09 +0000[diff] [blame]201<!--=========================================================================-->
202<div class="doc_subsection">
John Criswell98391ce2005-05-18 20:28:46 +0000[diff] [blame]203<a name="codequality">Code Generator Improvements in LLVM 1.6</a>
Chris Lattnerbf307012005-05-16 16:56:09 +0000[diff] [blame]204</div>
205
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]206<div class="doc_text">
207<ol>
208<li>The Alpha backend is substantially more stable and robust than in LLVM 1.5.
209 For example, it now fully supports varargs functions. The Alpha backend
210 also now features beta JIT support.</li>
211<li>The code generator contains a new component, the DAG Combiner. This allows
212 us to optimize lowered code (e.g. after 64-bit operations have been lowered
213 to use 32-bit registers on 32-bit targets) and do fine-grained bit-twiddling
214 optimizations for the backend.</li>
215<li>The SelectionDAG infrastructure is far more capable and mature, able to
216 handle many new target peculiarities in a target-independent way.</li>
217<li>The default <a href="http://llvm.org/PR547">register allocator is now far
218 faster on some testcases</a>,
219 particularly on targets with a large number of registers (e.g. IA64
220 and PPC).</li>
221</ol>
222</div>
223
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]224<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]225<div class="doc_subsection">
John Criswell98391ce2005-05-18 20:28:46 +0000[diff] [blame]226<a name="bugfix">Significant Bugs Fixed in LLVM 1.6</a>
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]227</div>
Reid Spencer8e0262f2004-05-23 17:23:13 +0000[diff] [blame]228
John Criswelle531ec52005-06-29 16:22:34 +0000[diff] [blame]229<div class="doc_text">
230<ol>
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]231 <li>A vast number of bugs have been fixed in the PowerPC backend and in
232 llvm-gcc when configured for Mac OS/X (particularly relating to ABI
233 issues). For example:
234 <a href="http://llvm.org/PR603">PR449</a>,
235 <a href="http://llvm.org/PR594">PR594</a>,
236 <a href="http://llvm.org/PR603">PR603</a>,
237 <a href="http://llvm.org/PR609">PR609</a>,
238 <a href="http://llvm.org/PR630">PR630</a>,
239 <a href="http://llvm.org/PR643">PR643</a>,
240 and several others without bugzilla bugs.</li>
241 <li>Several bugs in tail call support have been fixed.</li>
242 <li><a href="http://llvm.org/PR608">configure does not correctly detect gcc
243 version on cygwin</a>.</li>
244 <li>Many many other random bugs have been fixed. Query <a
245 href="http://llvm.org/bugs">our bugzilla</a> with a target of 1.6 for more
246 information.</li>
John Criswelle531ec52005-06-29 16:22:34 +0000[diff] [blame]247</ol>
248</div>
249
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]250<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]251<div class="doc_section">
252 <a name="portability">Portability and Supported Platforms</a>
253</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]254<!-- *********************************************************************** -->
255
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]256<div class="doc_text">
257
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]258<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]259
260<ul>
Reid Spencer00812e22005-05-17 02:47:27 +0000[diff] [blame]261 <li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
262 (and probably other unix-like systems).</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]263<li>Sun UltraSPARC workstations running Solaris 8.</li>
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]264<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
265 support is available for native builds with Visual C++).</li>
Chris Lattnerfeaf9602005-10-29 05:14:01 +0000[diff] [blame]266<li>PowerPC and X86-based Mac OS X systems, running 10.2 and above.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]267<li>Alpha-based machines running Debian GNU/Linux.</li>
268<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]269</ul>
270
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]271<p>The core LLVM infrastructure uses
272<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
273to the machine and operating system on which it is built. However, minor
274porting may be required to get LLVM to work on new platforms. We welcome your
275portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]276
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]277</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]278
279<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]280<div class="doc_section">
281 <a name="knownproblems">Known Problems</a>
282</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]283<!-- *********************************************************************** -->
284
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]285<div class="doc_text">
286
287<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]288component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]289sections. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]290href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]291there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]292
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]293</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]294
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]295<!-- ======================================================================= -->
296<div class="doc_subsection">
297 <a name="experimental">Experimental features included with this release</a>
298</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]299
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]300<div class="doc_text">
301
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]302<p>The following components of this LLVM release are either untested, known to
303be broken or unreliable, or are in early development. These components should
304not be relied on, and bugs should not be filed against them, but they may be
305useful to some people. In particular, if you would like to work on one of these
306components, please contact us on the llvmdev list.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]307
308<ul>
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]309<li>The following passes are incomplete or buggy, and may be removed in future
Chris Lattnere9412172005-10-24 02:33:44 +0000[diff] [blame]310 releases: <tt>-cee, -pre</tt></li>
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]311<li>The <tt>llvm-db</tt> tool is in a very early stage of development, but can
312 be used to step through programs and inspect the stack.</li>
Chris Lattnereaf0f2b2005-10-24 16:36:36 +0000[diff] [blame]313<li>The SparcV8 and IA64 code generators are experimental.</li>
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]314<li>The Alpha JIT is experimental.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]315</ul>
316
317</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]318
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]319<!-- ======================================================================= -->
320<div class="doc_subsection">
321 <a name="core">Known problems with the LLVM Core</a>
322</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]323
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]324<div class="doc_text">
325
326<ul>
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]327 <li>In the JIT, <tt>dlsym()</tt> on a symbol compiled by the JIT will not
328 work.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]329</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]330</div>
331
332<!-- ======================================================================= -->
333<div class="doc_subsection">
334 <a name="c-fe">Known problems with the C front-end</a>
335</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]336
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]337<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]338<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]339
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]340<div class="doc_text">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]341<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]342<li>C99 Variable sized arrays do not release stack memory when they go out of
343 scope. Thus, the following program may run out of stack space:
344<pre>
345 for (i = 0; i != 1000000; ++i) {
346 int X[n];
347 foo(X);
348 }
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]349</pre></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]350
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]351<li>Initialization of global union variables can only be done <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]352href="http://llvm.org/PR162">with the largest union member</a>.</li>
Chris Lattnerf580cdc2004-03-16 21:39:04 +0000[diff] [blame]353
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]354</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]355</div>
356
357<!-- _______________________________________________________________________ -->
358<div class="doc_subsubsection">
359 Notes
360</div>
361
362<div class="doc_text">
363
364<ul>
365
366<li>Inline assembly is not yet supported.</li>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]367
368<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]369support for floating point data types of any size other than 32 and 64
370bits.</li>
371
372<li>The following Unix system functionality has not been tested and may not
373work:
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]374 <ol>
375 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
376 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
377 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
378 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
379 - These functions have not been tested.
380 </ol></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]381
382<li>Although many GCC extensions are supported, some are not. In particular,
383 the following extensions are known to <b>not be</b> supported:
384 <ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]385 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]386 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html#Nested%20Functions">Nested Functions</a>: As in Algol and Pascal, lexical scoping of functions.</li>
387 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
388 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Extended%20Asm">Extended Asm</a>: Assembler instructions with C expressions as operands.</li>
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]389 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]390 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Asm-Labels.html#Asm%20Labels">Asm Labels</a>: Specifying the assembler name to use for a C symbol.</li>
391 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Explicit-Reg-Vars.html#Explicit%20Reg%20Vars">Explicit Reg Vars</a>: Defining variables residing in specified registers.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]392 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions.</li>
393 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.</li>
Tanya Lattner014e5f52004-12-08 18:25:34 +0000[diff] [blame]394 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]395 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]396 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]397
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]398 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]399 attribute means that the LLVM compiler ignores the presence of the attribute,
400 but the code should still work. An unsupported attribute is one which is
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]401 ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]402 the program.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]403
404 <ol>
405 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
406 Arrays whose length is computed at run time.<br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]407 Supported, but allocated stack space is not freed until the function returns (noted above).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]408
409 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]410
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]411 Declaring that functions have no side effects or that they can never
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]412 return.<br>
413
414 <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]415 <tt>noreturn</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
416 <tt>unused</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]417 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
418
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]419 <b>Ignored:</b> <tt>noinline</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]420 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
421 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
422
423 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>,
424 <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
425 <tt>fastcall</tt>, all other target specific attributes</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]426
427 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
428 Specifying attributes of variables.<br>
429 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
430 <tt>deprecated</tt>, <tt>transparent_union</tt>,
431 <tt>unused</tt>, <tt>weak</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]432
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]433 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
434 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
435 <tt>vector_size</tt>, <tt>dllimport</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]436 <tt>dllexport</tt>, all target specific attributes.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]437
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]438 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.<br>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]439 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]440 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]441
442 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
443 all target specific attributes.</li>
444
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]445 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
446 Other built-in functions.<br>
447 We support all builtins which have a C language equivalent (e.g.,
448 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
449 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Chris Lattnerceebeb62004-06-18 06:26:29 +0000[diff] [blame]450 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
451 (currently ignored). We also support builtins for ISO C99 floating
Chris Lattner7939b782005-05-07 02:21:21 +0000[diff] [blame]452 point comparison macros (e.g., <tt>__builtin_islessequal</tt>),
453 <tt>__builtin_prefetch</tt>, <tt>__builtin_popcount[ll]</tt>,
454 <tt>__builtin_clz[ll]</tt>, and <tt>__builtin_ctz[ll]</tt>.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]455 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]456
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]457 <p>The following extensions <b>are</b> known to be supported:</p>
458
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]459 <ol>
Chris Lattner7fe97dd2004-03-16 08:54:07 +0000[diff] [blame]460 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Labels-as-Values.html#Labels%20as%20Values">Labels as Values</a>: Getting pointers to labels and computed gotos.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]461 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
462 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Typeof.html#Typeof">Typeof</a>: <code>typeof</code>: referring to the type of an expression.</li>
Tanya Lattnerca26c3e2004-06-22 03:48:17 +0000[diff] [blame]463 <li><a href="http://gcc.gnu.org/onlinedocs/gcc-3.4.0/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]464 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
465 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
466 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
467 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
468 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
469 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
470 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variadic-Macros.html#Variadic%20Macros">Variadic Macros</a>: Macros with a variable number of arguments.</li>
471 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
472 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Subscripting.html#Subscripting">Subscripting</a>: Any array can be subscripted, even if not an lvalue.</li>
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]473 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pointer-Arith.html#Pointer%20Arith">Pointer Arith</a>: Arithmetic on <code>void</code>-pointers and function pointers.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]474 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]475 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
476or arrays as values.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]477 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.</li>
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]478 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Cast-to-Union.html#Cast%20to%20Union">Cast to Union</a>: Casting to union type from any member of the union.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]479 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
480 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
481 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
Tanya Lattner78537e42004-12-08 18:29:38 +0000[diff] [blame]482 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Comments.html#C_002b_002b-Comments">C++ Comments</a>: C++ comments are recognized.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]483 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
484 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Character-Escapes.html#Character%20Escapes">Character Escapes</a>: <code>\e</code> stands for the character &lt;ESC&gt;.</li>
485 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
486 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
487 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alternate-Keywords.html#Alternate%20Keywords">Alternate Keywords</a>:<code>__const__</code>, <code>__asm__</code>, etc., for header files.</li>
488 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Incomplete-Enums.html#Incomplete%20Enums">Incomplete Enums</a>: <code>enum foo;</code>, with details to follow.</li>
489 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Names.html#Function%20Names">Function Names</a>: Printable strings which are the name of the current function.</li>
Chris Lattner25795bc2004-02-14 04:08:29 +0000[diff] [blame]490 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Return-Address.html#Return%20Address">Return Address</a>: Getting the return or frame address of a function.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]491 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html#Unnamed%20Fields">Unnamed Fields</a>: Unnamed struct/union fields within structs/unions.</li>
492 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.</li>
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]493 </ol></li>
494
495</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]496
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]497<p>If you run into GCC extensions which have not been included in any of these
498lists, please let us know (also including whether or not they work).</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]499
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]500</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]501
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]502<!-- ======================================================================= -->
503<div class="doc_subsection">
504 <a name="c++-fe">Known problems with the C++ front-end</a>
505</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]506
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]507<div class="doc_text">
508
Reid Spencere09ca642004-12-07 08:39:08 +0000[diff] [blame]509<p>For this release, the C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]510tested and works for a number of non-trivial programs, including LLVM
511itself.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]512
513</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]514
515<!-- _______________________________________________________________________ -->
Chris Lattner3a51be12004-02-14 04:12:41 +0000[diff] [blame]516<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]517
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]518<div class="doc_text">
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]519
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]520<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]521<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]522 front-end</a>.</li>
Chris Lattner7962f712004-07-17 02:04:41 +0000[diff] [blame]523
Chris Lattnerd5713882004-08-02 20:28:44 +0000[diff] [blame]524</ul>
525
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]526</div>
527
528<!-- _______________________________________________________________________ -->
529<div class="doc_subsubsection">
530 Notes
531</div>
532
533<div class="doc_text">
534
535<ul>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]536
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]537<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
538parser is significantly more standards compliant (and picky) than prior GCC
539versions. For more information, see the C++ section of the <a
Chris Lattner9e848092003-12-12 04:25:33 +0000[diff] [blame]540href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]541
542<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]543 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]544 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]545 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]546 better than most compilers).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]547
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]548<li>The LLVM C++ front-end follows the <a
549 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
550 This document, which is not Itanium specific, specifies a standard for name
551 mangling, class layout, v-table layout, RTTI formats, and other C++
552 representation issues. Because we use this API, code generated by the LLVM
553 compilers should be binary compatible with machine code generated by other
554 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
555 <i>However</i>, the exception handling mechanism used by LLVM is very
556 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]557 interact correctly</b>. </li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]558
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]559</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]560
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]561</div>
562
563<!-- ======================================================================= -->
564<div class="doc_subsection">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]565 <a name="c-be">Known problems with the C back-end</a>
566</div>
567
568<div class="doc_text">
569
570<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]571
572<li>The C back-end produces code that violates the ANSI C Type-Based Alias
573Analysis rules. As such, special options may be necessary to compile the code
574(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]575problem probably cannot be fixed.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]576
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]577<li><a href="http://llvm.org/PR56">Zero arg vararg functions are not
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]578supported</a>. This should not affect LLVM produced by the C or C++
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]579frontends.</li>
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]580
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]581</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]582
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]583</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]584
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000[diff] [blame]585<!-- ======================================================================= -->
586<div class="doc_subsection">
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]587 <a name="x86-be">Known problems with the X86 back-end</a>
588</div>
589
590<div class="doc_text">
591
592<ul>
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]593<li><a href="http://llvm.org/PR566">Memory Mapped I/O Intrinsics do not fence
594memory</a></li>
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]595</ul>
596
597</div>
598
599<!-- ======================================================================= -->
600<div class="doc_subsection">
601 <a name="ppc-be">Known problems with the PowerPC back-end</a>
602</div>
603
604<div class="doc_text">
605
606<ul>
607<li>None yet</li>
608</ul>
609
610</div>
611
612<!-- ======================================================================= -->
613<div class="doc_subsection">
614 <a name="sparcv9-be">Known problems with the SparcV9 back-end</a>
615</div>
616
617<div class="doc_text">
618
619<ul>
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]620<li><a href="http://llvm.org/PR60">[sparcv9] SparcV9 backend miscompiles
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]621several programs in the LLVM test suite</a></li>
622</ul>
623
624</div>
625
626<!-- ======================================================================= -->
627<div class="doc_subsection">
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000[diff] [blame]628 <a name="alpha-be">Known problems with the Alpha back-end</a>
629</div>
630
631<div class="doc_text">
632
633<ul>
634
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]635<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
636appropriate nops inserted to ensure restartability.</li>
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000[diff] [blame]637
Andrew Lenharth01f40b32005-05-14 17:43:00 +0000[diff] [blame]638<li>Due to the vararg problems, C++ exceptions do not work. Small changes are required to the CFE (which break correctness in the exception handler) to compile the exception handling library (and thus the C++ standard library).</li>
639
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000[diff] [blame]640</ul>
641
642</div>
643
Duraid Madina2e36d6e2005-05-14 05:48:13 +0000[diff] [blame]644<!-- ======================================================================= -->
645<div class="doc_subsection">
646 <a name="ia64-be">Known problems with the IA64 back-end</a>
647</div>
648
649<div class="doc_text">
650
651<ul>
652
653<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
654made where the argument is not 16-byte aligned, as required on IA64. (Strictly
655speaking this is not a bug in the IA64 back-end; it will also be encountered
656when building C++ programs using the C back-end.)</li>
657
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]658<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]659ABI compliant layout of v-tables</a>. In particular, it just stores function
660pointers instead of function descriptors in the vtable. This bug prevents
661mixing C++ code compiled with LLVM with C++ objects compiled by other C++
662compilers.</li>
Duraid Madina2e36d6e2005-05-14 05:48:13 +0000[diff] [blame]663
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]664<li>There are a few ABI violations which will lead to problems when mixing LLVM
665output with code built with other compilers, particularly for floating-point
666programs.</li>
667
668<li>Defining vararg functions is not supported (but calling them is ok).</li>
Duraid Madina2e36d6e2005-05-14 05:48:13 +0000[diff] [blame]669
670</ul>
671
672</div>
673
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]674<!-- ======================================================================= -->
675<div class="doc_subsection">
676 <a name="sparcv8">Known problems with the SPARC-V8 back-end</a>
677</div>
678
679<div class="doc_text">
680
681<ul>
682<li>Many features are still missing (e.g. support for 64-bit integer
Chris Lattnerfeaf9602005-10-29 05:14:01 +0000[diff] [blame]683arithmetic). This back-end is in pre-beta state.</li>
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]684</ul>
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]685</div>
686
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]687<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]688<div class="doc_section">
689 <a name="additionalinfo">Additional Information</a>
690</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]691<!-- *********************************************************************** -->
692
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]693<div class="doc_text">
694
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]695<p>A wide variety of additional information is available on the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]696href="http://llvm.org">LLVM web page</a>, including <a
697href="http://llvm.org/docs/">documentation</a> and <a
698href="http://llvm.org/pubs/">publications describing algorithms and
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]699components implemented in LLVM</a>. The web page also contains versions of the
700API documentation which is up-to-date with the CVS version of the source code.
701You can access versions of these documents specific to this release by going
702into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]703
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]704<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^]705us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]706lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]707
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]708</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]709
710<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]711
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]712<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]713<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]714 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]715 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
716 <a href="http://validator.w3.org/check/referer"><img
717 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
718
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame^]719 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]720 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]721</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]722
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]723</body>
724</html>