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Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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4<head>
Reid Spencere4190fa2004-11-18 18:38:58 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]6 <link rel="stylesheet" href="llvm.css" type="text/css">
John Criswellfee5f112005-05-18 20:28:46 +0000[diff] [blame]7 <title>LLVM 1.6 Release Notes</title>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]8</head>
9<body>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]10
John Criswellfee5f112005-05-18 20:28:46 +0000[diff] [blame]11<div class="doc_title">LLVM 1.6 Release Notes</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]12
13<ol>
Misha Brukman80731b92003-11-22 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 Lattner77a51732004-04-30 22:17:12 +0000[diff] [blame]16 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]18 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]19 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]20</ol>
21
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]22<div class="doc_author">
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame^]23 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]24</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]25
26<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]27<div class="doc_section">
28 <a name="intro">Introduction</a>
29</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]30<!-- *********************************************************************** -->
31
Misha Brukman80731b92003-11-22 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 Criswellfee5f112005-05-18 20:28:46 +0000[diff] [blame]35infrastructure, release 1.6. Here we describe the status of LLVM, including any
Chris Lattner406bddf2005-05-15 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 Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame^]38href="http://llvm.org/releases/1.6/">LLVM 1.6 web site</a>. If you are
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]39not reading this on the LLVM web pages, you should probably go there because
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]40this document may be updated after the release.</p>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]41
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]42<p>For more information about LLVM, including information about the latest
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame^]43release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattnere7525b52003-10-07 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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]46list</a> is a good place to send them.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]47
Chris Lattnerf3a7c242004-12-09 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 Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame^]51href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]52
53</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]54
55<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]56<div class="doc_section">
57 <a name="whatsnew">What's New?</a>
58</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]59<!-- *********************************************************************** -->
60
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]61<div class="doc_text">
62
Chris Lattnera69595e2005-10-29 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 Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]69
Chris Lattner21a90402004-05-24 04:50:25 +0000[diff] [blame]70</div>
71
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]72<!--=========================================================================-->
Chris Lattner406bddf2005-05-15 05:44:51 +0000[diff] [blame]73<div class="doc_subsection">
John Criswellfee5f112005-05-18 20:28:46 +0000[diff] [blame]74<a name="newfeatures">New Features in LLVM 1.6</a>
Chris Lattner21a90402004-05-24 04:50:25 +0000[diff] [blame]75</div>
Brian Gaeke8b05e4f2004-01-16 21:55:04 +0000[diff] [blame]76
Chris Lattnera69595e2005-10-29 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 Lattnerf30c73c2005-05-18 22:23:56 +0000[diff] [blame]157<div class="doc_text">
Reid Spencer4386e4a2005-07-12 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 Lattnera69595e2005-10-29 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 Spencer4386e4a2005-07-12 16:36:24 +0000[diff] [blame]164 </li>
Chris Lattnera69595e2005-10-29 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 Spencer4386e4a2005-07-12 16:36:24 +0000[diff] [blame]177</ol>
Chris Lattnerf30c73c2005-05-18 22:23:56 +0000[diff] [blame]178</div>
179
Brian Gaeke8b05e4f2004-01-16 21:55:04 +0000[diff] [blame]180<!--=========================================================================-->
Chris Lattner406bddf2005-05-15 05:44:51 +0000[diff] [blame]181<div class="doc_subsection">
John Criswellfee5f112005-05-18 20:28:46 +0000[diff] [blame]182<a name="codequality">Code Quality Improvements in LLVM 1.6</a>
Chris Lattner23257062004-05-23 20:42:08 +0000[diff] [blame]183</div>
Chris Lattner639579c2003-10-27 17:06:39 +0000[diff] [blame]184
Chris Lattnera69595e2005-10-29 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 Lattner7e1f2622005-05-16 16:56:09 +0000[diff] [blame]201<!--=========================================================================-->
202<div class="doc_subsection">
John Criswellfee5f112005-05-18 20:28:46 +0000[diff] [blame]203<a name="codequality">Code Generator Improvements in LLVM 1.6</a>
Chris Lattner7e1f2622005-05-16 16:56:09 +0000[diff] [blame]204</div>
205
Chris Lattnera69595e2005-10-29 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 Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]224<!--=========================================================================-->
Chris Lattner406bddf2005-05-15 05:44:51 +0000[diff] [blame]225<div class="doc_subsection">
John Criswellfee5f112005-05-18 20:28:46 +0000[diff] [blame]226<a name="bugfix">Significant Bugs Fixed in LLVM 1.6</a>
Chris Lattner21a90402004-05-24 04:50:25 +0000[diff] [blame]227</div>
Reid Spencer3e58f582004-05-23 17:23:13 +0000[diff] [blame]228
John Criswell51e2a482005-06-29 16:22:34 +0000[diff] [blame]229<div class="doc_text">
230<ol>
Chris Lattnera69595e2005-10-29 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 Criswell51e2a482005-06-29 16:22:34 +0000[diff] [blame]247</ol>
248</div>
249
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]250<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]251<div class="doc_section">
252 <a name="portability">Portability and Supported Platforms</a>
253</div>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]254<!-- *********************************************************************** -->
255
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]256<div class="doc_text">
257
John Criswell64307722004-12-08 20:35:47 +0000[diff] [blame]258<p>LLVM is known to work on the following platforms:</p>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]259
260<ul>
Reid Spencer9803b402005-05-17 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 Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]263<li>Sun UltraSPARC workstations running Solaris 8.</li>
Chris Lattnerb5bb5972004-12-07 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 Lattner8ad30362005-10-29 05:14:01 +0000[diff] [blame]266<li>PowerPC and X86-based Mac OS X systems, running 10.2 and above.</li>
John Criswelld5234922005-05-13 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 Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]269</ul>
270
Brian Gaekee3e557e2004-05-09 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 Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]276
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]277</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]278
279<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]280<div class="doc_section">
281 <a name="knownproblems">Known Problems</a>
282</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]283<!-- *********************************************************************** -->
284
Misha Brukman80731b92003-11-22 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 Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]288component. As new problems are discovered, they will be added to these
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]289sections. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame^]290href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]291there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]292
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]293</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]294
Chris Lattnerb911de42004-03-14 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 Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]299
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]300<div class="doc_text">
301
Misha Brukmanfa50a222004-05-12 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 Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]307
308<ul>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]309<li>The following passes are incomplete or buggy, and may be removed in future
Chris Lattner7f37ab42005-10-24 02:33:44 +0000[diff] [blame]310 releases: <tt>-cee, -pre</tt></li>
Chris Lattnerb5bb5972004-12-07 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 Lattner0e18bdf2005-10-24 16:36:36 +0000[diff] [blame]313<li>The SparcV8 and IA64 code generators are experimental.</li>
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame^]314<li>The Alpha JIT is experimental.</li>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]315</ul>
316
317</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]318
Misha Brukman80731b92003-11-22 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 Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]323
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]324<div class="doc_text">
325
326<ul>
Misha Brukman96158092005-03-30 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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]329</ul>
Misha Brukman80731b92003-11-22 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 Lattner178f3db2003-10-02 05:07:23 +0000[diff] [blame]336
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]337<!-- _______________________________________________________________________ -->
Chris Lattner5a8a7282003-12-14 05:03:43 +0000[diff] [blame]338<div class="doc_subsubsection">Bugs</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]339
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]340<div class="doc_text">
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]341<ul>
Chris Lattner3d482502003-10-02 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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]349</pre></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]350
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]351<li>Initialization of global union variables can only be done <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame^]352href="http://llvm.org/PR162">with the largest union member</a>.</li>
Chris Lattner1ab58dd2004-03-16 21:39:04 +0000[diff] [blame]353
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]354</ul>
Misha Brukman80731b92003-11-22 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 Lattnerd2a74272003-10-27 18:30:37 +0000[diff] [blame]367
368<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman80731b92003-11-22 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 Brukman7cb4e382003-11-22 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 Lattner3d482502003-10-02 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 Brukman80731b92003-11-22 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 Brukman80731b92003-11-22 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 Criswell86a3a482003-12-18 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 Brukman80731b92003-11-22 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 Brukman80731b92003-11-22 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 Lattner63371342004-12-08 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 Brukman80731b92003-11-22 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 Brukman7cb4e382003-11-22 01:00:11 +0000[diff] [blame]396 </ol>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]397
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]398 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner3d482502003-10-02 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 Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]401 ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]402 the program.</p>
Chris Lattner3d482502003-10-02 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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]407 Supported, but allocated stack space is not freed until the function returns (noted above).</li>
Chris Lattner3d482502003-10-02 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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]410
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]411 Declaring that functions have no side effects or that they can never
Misha Brukman80731b92003-11-22 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 Criswell64307722004-12-08 20:35:47 +0000[diff] [blame]415 <tt>noreturn</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
416 <tt>unused</tt>,
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]417 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
418
John Criswell64307722004-12-08 20:35:47 +0000[diff] [blame]419 <b>Ignored:</b> <tt>noinline</tt>,
Misha Brukman80731b92003-11-22 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 Lattner3d482502003-10-02 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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]432
Chris Lattner3d482502003-10-02 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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]436 <tt>dllexport</tt>, all target specific attributes.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]437
Misha Brukman8395d732003-12-12 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 Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]439 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukman8395d732003-12-12 04:37:31 +0000[diff] [blame]440 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman80731b92003-11-22 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 Lattner3d482502003-10-02 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 Lattnerb7c4bac2004-06-18 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 Lattnerb34b2732005-05-07 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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]455 </ol>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]456
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]457 <p>The following extensions <b>are</b> known to be supported:</p>
458
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]459 <ol>
Chris Lattnerd3dc8502004-03-16 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 Brukman80731b92003-11-22 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 Lattnerce33a1b2004-06-22 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 Brukman80731b92003-11-22 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 Brukman8395d732003-12-12 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 Brukman80731b92003-11-22 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 Criswell86a3a482003-12-18 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 Brukman80731b92003-11-22 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 Brukman8395d732003-12-12 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 Brukman80731b92003-11-22 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 Lattner7591b822004-12-08 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 Brukman80731b92003-11-22 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 Lattner3646dad2004-02-14 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 Brukman80731b92003-11-22 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 Brukman7cb4e382003-11-22 01:00:11 +0000[diff] [blame]493 </ol></li>
494
495</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]496
Misha Brukman80731b92003-11-22 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 Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]499
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]500</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]501
Misha Brukman80731b92003-11-22 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 Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]506
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]507<div class="doc_text">
508
Reid Spencer55684c32004-12-07 08:39:08 +0000[diff] [blame]509<p>For this release, the C++ front-end is considered to be fully
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]510tested and works for a number of non-trivial programs, including LLVM
511itself.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]512
513</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]514
515<!-- _______________________________________________________________________ -->
Chris Lattner141ebb62004-02-14 04:12:41 +0000[diff] [blame]516<div class="doc_subsubsection">Bugs</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]517
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]518<div class="doc_text">
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]519
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]520<ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]521<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]522 front-end</a>.</li>
Chris Lattner041e6c92004-07-17 02:04:41 +0000[diff] [blame]523
Chris Lattner5cd40922004-08-02 20:28:44 +0000[diff] [blame]524</ul>
525
Misha Brukman80731b92003-11-22 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 Lattnerd2a74272003-10-27 18:30:37 +0000[diff] [blame]536
Chris Lattner3d482502003-10-02 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 Lattnere76e9ab2003-12-12 04:25:33 +0000[diff] [blame]540href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]541
542<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]543 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]544 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]545 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]546 better than most compilers).</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]547
Chris Lattner62495762003-10-02 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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]557 interact correctly</b>. </li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]558
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]559</ul>
Chris Lattner46ecf612003-10-07 22:14:37 +0000[diff] [blame]560
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]561</div>
562
563<!-- ======================================================================= -->
564<div class="doc_subsection">
Misha Brukman80731b92003-11-22 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 Lattner3d482502003-10-02 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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]575problem probably cannot be fixed.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]576
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame^]577<li><a href="http://llvm.org/PR56">Zero arg vararg functions are not
Chris Lattnerb28c3282003-10-24 04:03:19 +0000[diff] [blame]578supported</a>. This should not affect LLVM produced by the C or C++
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]579frontends.</li>
Chris Lattnerb28c3282003-10-24 04:03:19 +0000[diff] [blame]580
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]581</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]582
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]583</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]584
Andrew Lenharth2e18c622005-05-03 16:59:09 +0000[diff] [blame]585<!-- ======================================================================= -->
586<div class="doc_subsection">
Chris Lattner683a8472005-05-16 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 Lattnera69595e2005-10-29 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 Lattner683a8472005-05-16 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 Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame^]620<li><a href="http://llvm.org/PR60">[sparcv9] SparcV9 backend miscompiles
Chris Lattner683a8472005-05-16 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 Lenharth2e18c622005-05-03 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 Lattner683a8472005-05-16 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 Lenharth2e18c622005-05-03 16:59:09 +0000[diff] [blame]637
Andrew Lenharth8ecaa452005-05-14 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 Lenharth2e18c622005-05-03 16:59:09 +0000[diff] [blame]640</ul>
641
642</div>
643
Duraid Madina9a449002005-05-14 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 Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame^]658<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
Chris Lattner683a8472005-05-16 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 Madina9a449002005-05-14 05:48:13 +0000[diff] [blame]663
Chris Lattner683a8472005-05-16 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 Madina9a449002005-05-14 05:48:13 +0000[diff] [blame]669
670</ul>
671
672</div>
673
Chris Lattnerb62a5f02005-05-15 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 Lattner8ad30362005-10-29 05:14:01 +0000[diff] [blame]683arithmetic). This back-end is in pre-beta state.</li>
Chris Lattnerb62a5f02005-05-15 16:01:20 +0000[diff] [blame]684</ul>
Chris Lattnerb62a5f02005-05-15 16:01:20 +0000[diff] [blame]685</div>
686
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]687<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]688<div class="doc_section">
689 <a name="additionalinfo">Additional Information</a>
690</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]691<!-- *********************************************************************** -->
692
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]693<div class="doc_text">
694
Chris Lattnercb5596d2005-05-16 17:13:10 +0000[diff] [blame]695<p>A wide variety of additional information is available on the <a
Chris Lattnera69595e2005-10-29 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 Brukman96158092005-03-30 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 Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]703
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]704<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame^]705us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]706lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]707
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]708</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]709
710<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]711
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]712<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]713<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000[diff] [blame]714 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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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 Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame^]719 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]720 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]721</address>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]722
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]723</body>
724</html>