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Chris Lattner2974b5b2004-04-01 00:41:31 +00006 <title>LLVM 1.3 Release Notes</title>
Misha Brukman500bc302003-11-22 00:38:41 +00007</head>
8<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +00009
Chris Lattner2974b5b2004-04-01 00:41:31 +000010<div class="doc_title">LLVM 1.3 Release Notes</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000011
12<ol>
Misha Brukman500bc302003-11-22 00:38:41 +000013 <li><a href="#intro">Introduction</a></li>
14 <li><a href="#whatsnew">What's New?</a></li>
15 <li><a href="#portability">Portability and Supported Platforms</a></li>
16 <li><a href="#install-instructions">Installation Instructions</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +000017 <li><a href="#knownproblems">Known Problems</a>
18 <ul>
Chris Lattner2974b5b2004-04-01 00:41:31 +000019 <li><a href="#experimental">Experimental features included in this
20 release</a>
Chris Lattner79c3fe12003-10-02 04:57:28 +000021 <li><a href="#core">Known problems with the LLVM Core</a>
22 <li><a href="#c-fe">Known problems with the C Front-end</a>
23 <li><a href="#c++-fe">Known problems with the C++ Front-end</a>
24 <li><a href="#x86-be">Known problems with the X86 Back-end</a>
25 <li><a href="#sparc-be">Known problems with the Sparc Back-end</a>
26 <li><a href="#c-be">Known problems with the C back-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +000027 </ul></li>
28 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +000029</ol>
30
Misha Brukmane0c891c2003-11-22 01:00:11 +000031<div class="doc_text">
John Criswelld000e1d2003-12-18 16:43:17 +000032 <p><b>Written by the <a href="http://llvm.cs.uiuc.edu">LLVM team</a></b><p>
Misha Brukman500bc302003-11-22 00:38:41 +000033</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000034
35<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +000036<div class="doc_section">
37 <a name="intro">Introduction</a>
38</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000039<!-- *********************************************************************** -->
40
Misha Brukman500bc302003-11-22 00:38:41 +000041<div class="doc_text">
42
43<p>This document contains the release notes for the LLVM compiler
Chris Lattner2974b5b2004-04-01 00:41:31 +000044infrastructure, release 1.3. Here we describe the status of LLVM, including any
John Criswelld000e1d2003-12-18 16:43:17 +000045known problems and bug fixes from the previous release. The most up-to-date
Misha Brukman500bc302003-11-22 00:38:41 +000046version of this document can be found on the <a
Chris Lattner2974b5b2004-04-01 00:41:31 +000047href="http://llvm.cs.uiuc.edu/releases/1.3/">LLVM 1.3 web site</a>. If you are
John Criswelld000e1d2003-12-18 16:43:17 +000048not reading this on the LLVM web pages, you should probably go there because
Misha Brukman500bc302003-11-22 00:38:41 +000049this document may be updated after the release.</p>
Chris Lattner19092612003-10-02 16:38:05 +000050
Misha Brukman500bc302003-11-22 00:38:41 +000051<p>For more information about LLVM, including information about potentially more
Chris Lattner47ad72c2003-10-07 21:38:31 +000052current releases, please check out the <a href="http://llvm.cs.uiuc.edu">main
53web site</a>. If you have questions or comments, the <a
54href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman500bc302003-11-22 00:38:41 +000055list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +000056
Chris Lattner9e848092003-12-12 04:25:33 +000057<p>Note that if you are reading this file from CVS, this document applies
58to the <i>next</i> release, not the current one. To see the release notes for
59the current or previous releases, see the <a
Misha Brukman500bc302003-11-22 00:38:41 +000060href="http://llvm.cs.uiuc.edu/releases/">releases page</a>.</p>
61
62</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000063
64<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +000065<div class="doc_section">
66 <a name="whatsnew">What's New?</a>
67</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000068<!-- *********************************************************************** -->
69
Misha Brukman500bc302003-11-22 00:38:41 +000070<div class="doc_text">
71
Chris Lattnera39719f2004-02-25 16:36:51 +000072<p>
Chris Lattner2974b5b2004-04-01 00:41:31 +000073This is the fourth public release of the LLVM compiler infrastructure.
Chris Lattnerb40efb32003-12-14 05:03:43 +000074</p>
Chris Lattnera5099962003-12-06 20:22:41 +000075
Chris Lattner835104c2004-03-17 03:54:41 +000076<p>
77At this time, LLVM is known to correctly compile and run all C &amp; C++ SPEC
78CPU2000 benchmarks, the Olden benchmarks, and the Ptrdist benchmarks. It has
79also been used to compile <b>many</b> other programs. LLVM now also works with
80a broad variety of C++ programs, though it has still received less testing than
81the C front-end.
Chris Lattnera5099962003-12-06 20:22:41 +000082</p>
83
Chris Lattnera5099962003-12-06 20:22:41 +000084<!--=========================================================================-->
85<div class="doc_subsubsection">
Chris Lattnera39719f2004-02-25 16:36:51 +000086<a name="newfeatures">This release implements the following new features:</a>
Chris Lattnera5099962003-12-06 20:22:41 +000087</div>
Chris Lattner47ad72c2003-10-07 21:38:31 +000088
89<ol>
Chris Lattner2974b5b2004-04-01 00:41:31 +000090<li>The LLVM <a href="LangRef.html#i_select"><tt>select</tt></a> instruction is
91now fully implemented and supported by all targets.</li>
Chris Lattner55ee0312003-11-19 22:05:38 +000092</ol>
Chris Lattner0ef19062003-11-08 04:28:55 +000093
Chris Lattnera5099962003-12-06 20:22:41 +000094
95<!--=========================================================================-->
96<div class="doc_subsubsection">
97In this release, the following missing features were implemented:
98</div>
Chris Lattner0ef19062003-11-08 04:28:55 +000099
100<ol>
Chris Lattner2974b5b2004-04-01 00:41:31 +0000101<li></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000102</ol>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000103
Chris Lattnera5099962003-12-06 20:22:41 +0000104
105<!--=========================================================================-->
106<div class="doc_subsubsection">
Chris Lattnera39719f2004-02-25 16:36:51 +0000107<a name="qualityofimp">In this release, the following Quality of Implementation issues were fixed:</a>
Chris Lattnere29ac162003-12-20 03:42:11 +0000108</div>
109
110<ol>
Chris Lattner2974b5b2004-04-01 00:41:31 +0000111<li></li>
Chris Lattnere29ac162003-12-20 03:42:11 +0000112</ol>
113
114<!--=========================================================================-->
115<div class="doc_subsubsection">
Chris Lattnera39719f2004-02-25 16:36:51 +0000116In this release, the following build problems were fixed:
Brian Gaeke6b31beb2004-01-16 21:55:04 +0000117</div>
118
119<ol>
Chris Lattner2974b5b2004-04-01 00:41:31 +0000120<li></li>
Brian Gaeke6b31beb2004-01-16 21:55:04 +0000121</ol>
122
123<!--=========================================================================-->
124<div class="doc_subsubsection">
Chris Lattnera39719f2004-02-25 16:36:51 +0000125<a name="codequality">In this release, the following Code Quality issues were fixed:</a>
Chris Lattnera5099962003-12-06 20:22:41 +0000126</div>
Chris Lattner89ca2b82003-10-27 17:06:39 +0000127
128<ol>
Chris Lattner2974b5b2004-04-01 00:41:31 +0000129<li></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000130</ol>
Chris Lattner89ca2b82003-10-27 17:06:39 +0000131
Chris Lattnera5099962003-12-06 20:22:41 +0000132
133<!--=========================================================================-->
134<div class="doc_subsubsection">
Chris Lattnera39719f2004-02-25 16:36:51 +0000135<a name="bugfix">In this release, the following bugs in the previous release were fixed:</a>
Chris Lattnera5099962003-12-06 20:22:41 +0000136</div>
137
138<p>Bugs in the LLVM Core:</p>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000139
140<ol>
Chris Lattner1869a462004-04-01 19:09:49 +0000141<li><a href="http://llvm.cs.uiuc.edu/PR306">[loopsimplify] Loop simplify incorrectly updates dominator information</a></li>
Chris Lattner56d0f112004-04-01 20:31:29 +0000142<li><a href="http://llvm.cs.uiuc.edu/PR310">[tailduplicate] DemoteRegToStack breaks SSA form</a></li>
Chris Lattnera5099962003-12-06 20:22:41 +0000143</ol>
144
145
Chris Lattner56e67052004-02-09 21:22:51 +0000146
Chris Lattnera5099962003-12-06 20:22:41 +0000147<p>Bugs in the C/C++ front-end:</p>
148
149<ol>
Chris Lattner2974b5b2004-04-01 00:41:31 +0000150<li></li>
Chris Lattnera5099962003-12-06 20:22:41 +0000151</ol>
Chris Lattner19092612003-10-02 16:38:05 +0000152
Misha Brukman500bc302003-11-22 00:38:41 +0000153</div>
Chris Lattner19092612003-10-02 16:38:05 +0000154
155<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000156<div class="doc_section">
157 <a name="portability">Portability and Supported Platforms</a>
158</div>
Chris Lattner19092612003-10-02 16:38:05 +0000159<!-- *********************************************************************** -->
160
Misha Brukman500bc302003-11-22 00:38:41 +0000161<div class="doc_text">
162
163<p>LLVM has been extensively tested on Intel and AMD machines running Red
Chris Lattnerb40efb32003-12-14 05:03:43 +0000164Hat Linux and FreeBSD. It has also been tested on Sun UltraSPARC workstations running Solaris 8.
John Criswellbb1bad52003-12-12 19:54:20 +0000165Additionally,
John Criswelld000e1d2003-12-18 16:43:17 +0000166LLVM works on Mac OS X 10.3 and above, but only with the C backend or
Chris Lattner9e848092003-12-12 04:25:33 +0000167interpreter (no native backend for the PowerPC is available yet).
Chris Lattner19092612003-10-02 16:38:05 +0000168The core LLVM infrastructure uses "autoconf" for portability, so hopefully we
Chris Lattner3e2959e2003-11-08 05:22:09 +0000169work on more platforms than that. However, it is likely that we
John Criswelld000e1d2003-12-18 16:43:17 +0000170missed something and that minor porting is required to get LLVM to work on
Misha Brukman500bc302003-11-22 00:38:41 +0000171new platforms. We welcome portability patches and error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000172
Misha Brukman500bc302003-11-22 00:38:41 +0000173</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000174
175<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000176<div class="doc_section">
177 <a name="knownproblems">Known Problems</a>
178</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000179<!-- *********************************************************************** -->
180
Misha Brukman500bc302003-11-22 00:38:41 +0000181<div class="doc_text">
182
183<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000184component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000185sections. If you run into a problem, please check the <a
John Criswelld000e1d2003-12-18 16:43:17 +0000186href="http://llvm.cs.uiuc.edu/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000187there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000188
Misha Brukman500bc302003-11-22 00:38:41 +0000189</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000190
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000191<!-- ======================================================================= -->
192<div class="doc_subsection">
193 <a name="experimental">Experimental features included with this release</a>
194</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000195
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000196<div class="doc_text">
197
198<p>
199The following components of this LLVM release are either untested, known to be
200broken or unreliable, or are in early development. These components should not
201be relied on, and bugs should not be filed against them, but they may be useful
202to some people. In particular, if you would like to work on one of these
203components, please contact us on the llvmdev list.
204</p>
205
206<ul>
207<li>The following passes are incomplete or buggy: <tt>-pgmdep, -memdep,
208 -ipmodref, -sortstructs, -swapstructs, -cee</tt></li>
209
210<li>The <tt>-pre</tt> pass is incomplete (there are cases it doesn't handle that
211 it should) and not thoroughly tested.</li>
212<li>The <tt>llvm-ar</tt> tool is incomplete and probably buggy.</li>
213<li>The <tt>llvm-db</tt> tool is in a very early stage of development.</li>
214</ul>
215
216</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000217
Misha Brukman500bc302003-11-22 00:38:41 +0000218<!-- ======================================================================= -->
219<div class="doc_subsection">
220 <a name="core">Known problems with the LLVM Core</a>
221</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000222
Misha Brukman500bc302003-11-22 00:38:41 +0000223<div class="doc_text">
224
225<ul>
226
227<li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not
228work.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000229
230<li>The JIT does not use mutexes to protect its internal data structures. As
Misha Brukman500bc302003-11-22 00:38:41 +0000231such, execution of a threaded program could cause these data structures to be
232corrupted.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000233
Misha Brukman500bc302003-11-22 00:38:41 +0000234<li>It is not possible to <tt>dlopen</tt> an LLVM bytecode file in the JIT.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000235
Chris Lattnere84843b2003-10-20 19:05:03 +0000236<li>Linking in static archive files (.a files) is very slow (there is no symbol
Misha Brukman500bc302003-11-22 00:38:41 +0000237table in the archive).</li>
Chris Lattner2855ecd2003-11-04 20:06:53 +0000238
Chris Lattner2855ecd2003-11-04 20:06:53 +0000239<li><a href="http://llvm.cs.uiuc.edu/PR82">LLVM cannot handle structures with
Misha Brukman500bc302003-11-22 00:38:41 +0000240more than 256 elements</a>.</li>
241
Chris Lattner2e6fcaf2004-02-15 23:09:07 +0000242<li>The gccld program <a href="http://llvm.cs.uiuc.edu/PR139">does not link objects/archives in the order specified on the command line.</a></li>
243
244<li><a href="http://llvm.cs.uiuc.edu/PR240">The lower-invoke pass does not mark
John Criswelld46c6962004-03-12 21:29:42 +0000245values live across a setjmp as volatile</a>. This missing feature only affects
Chris Lattner2e6fcaf2004-02-15 23:09:07 +0000246targets whose setjmp/longjmp libraries do not save and restore the entire
247register file.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000248</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000249</div>
250
251<!-- ======================================================================= -->
252<div class="doc_subsection">
253 <a name="c-fe">Known problems with the C front-end</a>
254</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000255
Chris Lattner79c3fe12003-10-02 04:57:28 +0000256<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000257<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000258
Misha Brukman500bc302003-11-22 00:38:41 +0000259<div class="doc_text">
Misha Brukman500bc302003-11-22 00:38:41 +0000260<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000261<li>C99 Variable sized arrays do not release stack memory when they go out of
262 scope. Thus, the following program may run out of stack space:
263<pre>
264 for (i = 0; i != 1000000; ++i) {
265 int X[n];
266 foo(X);
267 }
Misha Brukman500bc302003-11-22 00:38:41 +0000268</pre></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000269
John Criswelld000e1d2003-12-18 16:43:17 +0000270<li>
271Initialization of global union variables can only be done
272<a href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=162">with the largest
273union member</a>.
274</li>
Chris Lattnerf580cdc2004-03-16 21:39:04 +0000275
276<li><a href="http://llvm.cs.uiuc.edu/PR244">[llvm-gcc] Error when an implicitly external function is re-declared as static</a></li>
277
John Criswelld000e1d2003-12-18 16:43:17 +0000278</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000279</div>
280
281<!-- _______________________________________________________________________ -->
282<div class="doc_subsubsection">
283 Notes
284</div>
285
286<div class="doc_text">
287
288<ul>
289
290<li>Inline assembly is not yet supported.</li>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000291
292<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman500bc302003-11-22 00:38:41 +0000293support for floating point data types of any size other than 32 and 64
294bits.</li>
295
296<li>The following Unix system functionality has not been tested and may not
297work:
Misha Brukmane0c891c2003-11-22 01:00:11 +0000298 <ol>
299 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
300 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
301 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
302 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
303 - These functions have not been tested.
304 </ol></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000305
306<li>Although many GCC extensions are supported, some are not. In particular,
307 the following extensions are known to <b>not be</b> supported:
308 <ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000309 <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 +0000310 <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>
311 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
312 <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 +0000313 <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 +0000314 <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>
315 <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 +0000316 <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>
317 <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>
318 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables.</li>
319 <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 +0000320 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000321
Misha Brukman500bc302003-11-22 00:38:41 +0000322 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner79c3fe12003-10-02 04:57:28 +0000323 attribute means that the LLVM compiler ignores the presence of the attribute,
324 but the code should still work. An unsupported attribute is one which is
John Criswelld000e1d2003-12-18 16:43:17 +0000325 ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman500bc302003-11-22 00:38:41 +0000326 the program.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000327
328 <ol>
329 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
330 Arrays whose length is computed at run time.<br>
Misha Brukman500bc302003-11-22 00:38:41 +0000331 Supported, but allocated stack space is not freed until the function returns (noted above).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000332
333 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Misha Brukman500bc302003-11-22 00:38:41 +0000334
John Criswelld000e1d2003-12-18 16:43:17 +0000335 Declaring that functions have no side effects or that they can never
Misha Brukman500bc302003-11-22 00:38:41 +0000336 return.<br>
337
338 <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
339 <tt>constructor</tt>, <tt>destructor</tt>, <tt>unused</tt>,
340 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
341
342 <b>Ignored:</b> <tt>noreturn</tt>, <tt>noinline</tt>,
343 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
344 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
345
346 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>,
347 <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
348 <tt>fastcall</tt>, all other target specific attributes</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000349
350 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
351 Specifying attributes of variables.<br>
352 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
353 <tt>deprecated</tt>, <tt>transparent_union</tt>,
354 <tt>unused</tt>, <tt>weak</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000355
Chris Lattner79c3fe12003-10-02 04:57:28 +0000356 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
357 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
358 <tt>vector_size</tt>, <tt>dllimport</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000359 <tt>dllexport</tt>, all target specific attributes.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000360
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000361 <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 +0000362 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000363 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000364
365 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
366 all target specific attributes.</li>
367
Chris Lattner79c3fe12003-10-02 04:57:28 +0000368 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
369 Other built-in functions.<br>
370 We support all builtins which have a C language equivalent (e.g.,
371 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
372 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000373 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt> (ignored).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000374
Misha Brukman500bc302003-11-22 00:38:41 +0000375 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000376
Misha Brukman500bc302003-11-22 00:38:41 +0000377 <p>The following extensions <b>are</b> known to be supported:</p>
378
Chris Lattner79c3fe12003-10-02 04:57:28 +0000379 <ol>
Chris Lattner7fe97dd2004-03-16 08:54:07 +0000380 <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 +0000381 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
382 <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>
383 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
384 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
385 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
386 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
387 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
388 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
389 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
390 <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>
391 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
392 <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 +0000393 <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 +0000394 <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 +0000395 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
396or arrays as values.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000397 <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 +0000398 <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 +0000399 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
400 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
401 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
402 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized.</li>
403 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
404 <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>
405 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
406 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
407 <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>
408 <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>
409 <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 +0000410 <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 +0000411 <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>
412 <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 +0000413 </ol></li>
414
415</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000416
Misha Brukman500bc302003-11-22 00:38:41 +0000417<p>If you run into GCC extensions which have not been included in any of these
418lists, please let us know (also including whether or not they work).</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000419
Misha Brukman500bc302003-11-22 00:38:41 +0000420</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000421
Misha Brukman500bc302003-11-22 00:38:41 +0000422<!-- ======================================================================= -->
423<div class="doc_subsection">
424 <a name="c++-fe">Known problems with the C++ front-end</a>
425</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000426
Misha Brukman500bc302003-11-22 00:38:41 +0000427<div class="doc_text">
428
John Criswelld000e1d2003-12-18 16:43:17 +0000429<p>For this release, the C++ front-end is considered to be fully functional but
Chris Lattner9e848092003-12-12 04:25:33 +0000430has not been tested as thoroughly as the C front-end. It has been tested and
431works for a number of non-trivial programs, but there may be lurking bugs.
432Please report any bugs or problems.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000433
434</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000435
436<!-- _______________________________________________________________________ -->
Chris Lattner3a51be12004-02-14 04:12:41 +0000437<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000438
Misha Brukman500bc302003-11-22 00:38:41 +0000439<div class="doc_text">
Chris Lattner79c3fe12003-10-02 04:57:28 +0000440
Misha Brukman500bc302003-11-22 00:38:41 +0000441<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000442<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
John Criswelld000e1d2003-12-18 16:43:17 +0000443 front-end</a>.</li>
John Criswelld000e1d2003-12-18 16:43:17 +0000444</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000445</div>
446
447<!-- _______________________________________________________________________ -->
448<div class="doc_subsubsection">
449 Notes
450</div>
451
452<div class="doc_text">
453
454<ul>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000455
Chris Lattner79c3fe12003-10-02 04:57:28 +0000456<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
457parser is significantly more standards compliant (and picky) than prior GCC
458versions. For more information, see the C++ section of the <a
Chris Lattner9e848092003-12-12 04:25:33 +0000459href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000460
461<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
Chris Lattner19092612003-10-02 16:38:05 +0000462 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000463 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswelld000e1d2003-12-18 16:43:17 +0000464 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman500bc302003-11-22 00:38:41 +0000465 better than most compilers).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000466
Chris Lattner19092612003-10-02 16:38:05 +0000467<li>The LLVM C++ front-end follows the <a
468 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
469 This document, which is not Itanium specific, specifies a standard for name
470 mangling, class layout, v-table layout, RTTI formats, and other C++
471 representation issues. Because we use this API, code generated by the LLVM
472 compilers should be binary compatible with machine code generated by other
473 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
474 <i>However</i>, the exception handling mechanism used by LLVM is very
475 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman500bc302003-11-22 00:38:41 +0000476 interact correctly</b>. </li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000477
Misha Brukman500bc302003-11-22 00:38:41 +0000478</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000479
Misha Brukman500bc302003-11-22 00:38:41 +0000480</div>
481
482<!-- ======================================================================= -->
483<div class="doc_subsection">
484 <a name="x86-be">Known problems with the X86 back-end</a>
485</div>
486
487<div class="doc_text">
488
489<ul>
Chris Lattnerde4afdc2004-02-08 22:23:33 +0000490<li>None so far.
Misha Brukman500bc302003-11-22 00:38:41 +0000491</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000492
Misha Brukman500bc302003-11-22 00:38:41 +0000493</div>
494
495<!-- ======================================================================= -->
496<div class="doc_subsection">
497 <a name="sparc-be">Known problems with the Sparc back-end</a>
498</div>
499
500<div class="doc_text">
501
502<ul>
Chris Lattner6a39aa52004-03-19 19:22:28 +0000503<li>There are several programs in the LLVM testsuite that the Sparc code generator is known to miscompile.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000504</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000505
Misha Brukman500bc302003-11-22 00:38:41 +0000506</div>
507
508<!-- ======================================================================= -->
509<div class="doc_subsection">
510 <a name="c-be">Known problems with the C back-end</a>
511</div>
512
513<div class="doc_text">
514
515<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000516
517<li>The C back-end produces code that violates the ANSI C Type-Based Alias
518Analysis rules. As such, special options may be necessary to compile the code
519(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
Misha Brukman500bc302003-11-22 00:38:41 +0000520problem probably cannot be fixed.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000521
Chris Lattnere84843b2003-10-20 19:05:03 +0000522<li><a href="http://llvm.cs.uiuc.edu/PR33">Initializers for global variables</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000523cannot include special floating point numbers like Not-A-Number or
524Infinity.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000525
Chris Lattner2855ecd2003-11-04 20:06:53 +0000526<li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
Chris Lattner2af46052003-10-24 04:03:19 +0000527supported</a>. This should not affect LLVM produced by the C or C++
Misha Brukman500bc302003-11-22 00:38:41 +0000528frontends.</li>
Chris Lattner2af46052003-10-24 04:03:19 +0000529
Misha Brukman500bc302003-11-22 00:38:41 +0000530</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000531
Misha Brukman500bc302003-11-22 00:38:41 +0000532</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000533
534<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000535<div class="doc_section">
536 <a name="additionalinfo">Additional Information</a>
537</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000538<!-- *********************************************************************** -->
539
Misha Brukman500bc302003-11-22 00:38:41 +0000540<div class="doc_text">
541
542<p>A wide variety of additional information is available on the LLVM web page,
John Criswelld000e1d2003-12-18 16:43:17 +0000543including mailing lists and publications describing algorithms and components
Chris Lattner79c3fe12003-10-02 04:57:28 +0000544implemented in LLVM. The web page also contains versions of the API
545documentation which is up-to-date with the CVS version of the source code. You
546can access versions of these documents specific to this release by going into
Misha Brukman500bc302003-11-22 00:38:41 +0000547the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000548
Misha Brukman500bc302003-11-22 00:38:41 +0000549<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattner5eccca42003-12-12 21:22:16 +0000550us via the <a href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">mailing
551lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000552
Misha Brukman500bc302003-11-22 00:38:41 +0000553</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000554
555<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000556
Misha Brukman500bc302003-11-22 00:38:41 +0000557<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000558<address>
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563
Misha Brukmane0c891c2003-11-22 01:00:11 +0000564 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
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