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Chris Lattner163c3262004-08-16 00:20:18 +00006 <title>LLVM 1.4 Release Notes</title>
Misha Brukman80731b92003-11-22 00:38:41 +00007</head>
8<body>
Chris Lattner3d482502003-10-02 04:57:28 +00009
Chris Lattner163c3262004-08-16 00:20:18 +000010<div class="doc_title">LLVM 1.4 Release Notes</div>
Chris Lattner3d482502003-10-02 04:57:28 +000011
12<ol>
Misha Brukman80731b92003-11-22 00:38:41 +000013 <li><a href="#intro">Introduction</a></li>
14 <li><a href="#whatsnew">What's New?</a></li>
Chris Lattner77a51732004-04-30 22:17:12 +000015 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +000016 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +000017 <li><a href="#knownproblems">Known Problems</a>
18 <ul>
Chris Lattner1a7e43c2004-04-01 00:41:31 +000019 <li><a href="#experimental">Experimental features included in this
20 release</a>
Chris Lattner3d482502003-10-02 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>
Misha Brukmana516e992004-07-12 16:55:41 +000025 <li><a href="#sparcv9-be">Known problems with the SparcV9 Back-end</a>
Chris Lattner3d482502003-10-02 04:57:28 +000026 <li><a href="#c-be">Known problems with the C back-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +000027 </ul></li>
28 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +000029</ol>
30
Chris Lattner020e1fc2004-05-23 21:07:27 +000031<div class="doc_author">
32 <p>Written by the <a href="http://llvm.cs.uiuc.edu">LLVM team</a><p>
Misha Brukman80731b92003-11-22 00:38:41 +000033</div>
Chris Lattner3d482502003-10-02 04:57:28 +000034
35<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +000036<div class="doc_section">
37 <a name="intro">Introduction</a>
38</div>
Chris Lattner3d482502003-10-02 04:57:28 +000039<!-- *********************************************************************** -->
40
Misha Brukman80731b92003-11-22 00:38:41 +000041<div class="doc_text">
42
43<p>This document contains the release notes for the LLVM compiler
Chris Lattner163c3262004-08-16 00:20:18 +000044infrastructure, release 1.4. Here we describe the status of LLVM, including any
John Criswell86a3a482003-12-18 16:43:17 +000045known problems and bug fixes from the previous release. The most up-to-date
Misha Brukman80731b92003-11-22 00:38:41 +000046version of this document can be found on the <a
Chris Lattner163c3262004-08-16 00:20:18 +000047href="http://llvm.cs.uiuc.edu/releases/1.4/">LLVM 1.4 web site</a>. If you are
John Criswell86a3a482003-12-18 16:43:17 +000048not reading this on the LLVM web pages, you should probably go there because
Misha Brukman80731b92003-11-22 00:38:41 +000049this document may be updated after the release.</p>
Chris Lattner62495762003-10-02 16:38:05 +000050
Misha Brukman80731b92003-11-22 00:38:41 +000051<p>For more information about LLVM, including information about potentially more
Chris Lattnere7525b52003-10-07 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 Brukman80731b92003-11-22 00:38:41 +000055list</a> is a good place to send them.</p>
Chris Lattner3d482502003-10-02 04:57:28 +000056
Chris Lattnere76e9ab2003-12-12 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 Brukman80731b92003-11-22 00:38:41 +000060href="http://llvm.cs.uiuc.edu/releases/">releases page</a>.</p>
61
62</div>
Chris Lattner3d482502003-10-02 04:57:28 +000063
64<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +000065<div class="doc_section">
66 <a name="whatsnew">What's New?</a>
67</div>
Chris Lattner3d482502003-10-02 04:57:28 +000068<!-- *********************************************************************** -->
69
Misha Brukman80731b92003-11-22 00:38:41 +000070<div class="doc_text">
71
Chris Lattner163c3262004-08-16 00:20:18 +000072<p>This is the fifth public release of the LLVM compiler infrastructure.</p>
Chris Lattnerba7bd472003-12-06 20:22:41 +000073
Misha Brukmanfa50a222004-05-12 21:46:05 +000074<p> At this time, LLVM is known to correctly compile and run all C &amp; C++
Chris Lattner5cd40922004-08-02 20:28:44 +000075SPEC CPU95 &amp; 2000 benchmarks, the Olden benchmarks, and the Ptrdist
76benchmarks, and <b>many</b> other programs. LLVM now also works
77with a broad variety of C++ programs.</p>
Chris Lattnerba7bd472003-12-06 20:22:41 +000078
Chris Lattner21a90402004-05-24 04:50:25 +000079</div>
80
Chris Lattnerba7bd472003-12-06 20:22:41 +000081<!--=========================================================================-->
82<div class="doc_subsubsection">
Chris Lattner8ebf2532004-02-25 16:36:51 +000083<a name="newfeatures">This release implements the following new features:</a>
Chris Lattnerba7bd472003-12-06 20:22:41 +000084</div>
Chris Lattnere7525b52003-10-07 21:38:31 +000085
Chris Lattner21a90402004-05-24 04:50:25 +000086<div class="doc_text">
87
Chris Lattnere7525b52003-10-07 21:38:31 +000088<ol>
Chris Lattner163c3262004-08-16 00:20:18 +000089<li></li>
Chris Lattner592db402003-11-19 22:05:38 +000090</ol>
Chris Lattner4491de62003-11-08 04:28:55 +000091
Chris Lattner21a90402004-05-24 04:50:25 +000092</div>
93
Chris Lattnerba7bd472003-12-06 20:22:41 +000094
95<!--=========================================================================-->
96<div class="doc_subsubsection">
97In this release, the following missing features were implemented:
98</div>
Chris Lattner4491de62003-11-08 04:28:55 +000099
Chris Lattner21a90402004-05-24 04:50:25 +0000100<div class="doc_text">
101
Chris Lattner4491de62003-11-08 04:28:55 +0000102<ol>
Chris Lattner163c3262004-08-16 00:20:18 +0000103<li><a href="http://llvm.org/PR419">JIT interface should support arbitrary
104 calls</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000105</ol>
Chris Lattnere7525b52003-10-07 21:38:31 +0000106
Chris Lattner21a90402004-05-24 04:50:25 +0000107</div>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000108
109<!--=========================================================================-->
110<div class="doc_subsubsection">
Misha Brukman017f2f32004-04-19 02:56:49 +0000111<a name="qualityofimp">In this release, the following Quality of Implementation
112issues were fixed:</a>
Chris Lattner4df78f02003-12-20 03:42:11 +0000113</div>
114
Chris Lattner21a90402004-05-24 04:50:25 +0000115<div class="doc_text">
116
Chris Lattner4df78f02003-12-20 03:42:11 +0000117<ol>
Chris Lattner615ffb82004-08-20 00:36:23 +0000118<li><a href="http://llvm.org/PR426">[llvmg++] Tons of warnings are spewed when
119 linking to libstdc++</a></li>
Chris Lattner4df78f02003-12-20 03:42:11 +0000120</ol>
121
Chris Lattner21a90402004-05-24 04:50:25 +0000122</div>
123
Chris Lattner4df78f02003-12-20 03:42:11 +0000124<!--=========================================================================-->
125<div class="doc_subsubsection">
Chris Lattner8ebf2532004-02-25 16:36:51 +0000126In this release, the following build problems were fixed:
Brian Gaeke8b05e4f2004-01-16 21:55:04 +0000127</div>
128
Chris Lattner21a90402004-05-24 04:50:25 +0000129<div class="doc_text">
Brian Gaeke8b05e4f2004-01-16 21:55:04 +0000130<ol>
Chris Lattner163c3262004-08-16 00:20:18 +0000131<li></li>
Brian Gaeke8b05e4f2004-01-16 21:55:04 +0000132</ol>
Chris Lattner21a90402004-05-24 04:50:25 +0000133</div>
Brian Gaeke8b05e4f2004-01-16 21:55:04 +0000134
135<!--=========================================================================-->
136<div class="doc_subsubsection">
Chris Lattner2ad48782004-05-02 04:19:15 +0000137<a name="codequality">This release includes the following Code Quality
138improvements:</a>
Chris Lattner23257062004-05-23 20:42:08 +0000139</div>
Chris Lattner639579c2003-10-27 17:06:39 +0000140
Chris Lattner21a90402004-05-24 04:50:25 +0000141<div class="doc_text">
Chris Lattner639579c2003-10-27 17:06:39 +0000142<ol>
Reid Spencer05b9b532004-09-07 17:52:38 +0000143 <li><a href="http://llvm.org/PR257">move test/Programs out of the main llvm
144 tree</a></li>
145 <li><a href="http://llvm.org/PR352">include/{Support,Config} ->
146 include/llvm/{Support,Config}</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000147</ol>
Reid Spencer3e58f582004-05-23 17:23:13 +0000148</div>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000149
150<!--=========================================================================-->
151<div class="doc_subsubsection">
Misha Brukman017f2f32004-04-19 02:56:49 +0000152<a name="bugfix">In this release, the following bugs in the previous release
153were fixed:</a>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000154</div>
155
Chris Lattner21a90402004-05-24 04:50:25 +0000156<div class="doc_text">
157
Chris Lattner5cd40922004-08-02 20:28:44 +0000158<p>Bugs fixed in the LLVM Core:</p>
Chris Lattnere7525b52003-10-07 21:38:31 +0000159
160<ol>
Reid Spencerf03b47c2004-08-16 16:48:19 +0000161<li><a href="http://llvm.org/PR422">[asmwriter] Asmwriter is really slow for
162 functions with lots of values</a></li>
Chris Lattnera10ed3b2004-08-16 05:46:57 +0000163<li><a href="http://llvm.org/PR423">[anders-aa] Andersen's AA is completely
164 broken in LLVM 1.3</a></li>
Reid Spencer7d0a1232004-08-27 00:48:26 +0000165<li><a href="http://llvm.org/PR430">[bcwriter] Empty compaction tables
166 defined</a></li>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000167</ol>
168
Chris Lattnerba7bd472003-12-06 20:22:41 +0000169<p>Bugs in the C/C++ front-end:</p>
170
171<ol>
Chris Lattner163c3262004-08-16 00:20:18 +0000172<li></li>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000173</ol>
Brian Gaeke730d8d62004-08-24 07:43:48 +0000174
175<p>Bugs fixed in the Sparc V9 back-end:</p>
176
177<ol>
178<li><a href="http://llvm.org/PR428">[sparcv9] regalloc assertion
179 failure with certain indirect calls</a></li>
180</ol>
181
Chris Lattner21a90402004-05-24 04:50:25 +0000182</div>
Reid Spencer3e58f582004-05-23 17:23:13 +0000183
Chris Lattner62495762003-10-02 16:38:05 +0000184<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000185<div class="doc_section">
186 <a name="portability">Portability and Supported Platforms</a>
187</div>
Chris Lattner62495762003-10-02 16:38:05 +0000188<!-- *********************************************************************** -->
189
Misha Brukman80731b92003-11-22 00:38:41 +0000190<div class="doc_text">
191
Chris Lattner2c7b0872004-06-01 18:22:41 +0000192<p>LLVM is known to work in the following platforms:</p>
193
194<ul>
195<li>Intel and AMD machines running Red Hat Linux and FreeBSD (and probably
196 other unix-like systems).</li>
197<li>Sun UltraSPARC workstations running Solaris 8.</li>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000198<li>Intel and AMD machines running on Win32 with the Cygwin libraries.</li>
Chris Lattnerd21e3d02004-08-05 21:53:13 +0000199<li>PowerPC-based Mac OS X boxes, running 10.2 and above. Note that no JIT
200support is available yet, and LLC support is beta. The C backend can be used
201to produce stable code for this platform.</li>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000202</ul>
203
Brian Gaekee3e557e2004-05-09 05:28:35 +0000204<p>The core LLVM infrastructure uses
205<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
206to the machine and operating system on which it is built. However, minor
207porting may be required to get LLVM to work on new platforms. We welcome your
208portability patches and reports of successful builds or error messages.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000209
Chris Lattner2c7b0872004-06-01 18:22:41 +0000210<p>Note that the LLVM build system does not currently support directories with
211spaces on them when running on Win32/cygwin. We strongly recommend running
212LLVM and the C frontend out of a top-level directory without spaces (e.g.,
Chris Lattnerce1a3842004-06-01 19:41:30 +0000213<tt>/cygdrive/c/llvm</tt>). Also, make sure to install <b>all</b> of the
214cygwin packages. By default, many important tools are not installed that
Chris Lattnera752fce2004-08-16 20:20:46 +0000215are needed by the LLVM build process or test suite (e.g., /bin/time). Finally,
216please make sure that there are no directories with spaces in them in your
217PATH environment variable.</p>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000218
Misha Brukman80731b92003-11-22 00:38:41 +0000219</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000220
221<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000222<div class="doc_section">
223 <a name="knownproblems">Known Problems</a>
224</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000225<!-- *********************************************************************** -->
226
Misha Brukman80731b92003-11-22 00:38:41 +0000227<div class="doc_text">
228
229<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner3d482502003-10-02 04:57:28 +0000230component. As new problems are discovered, they will be added to these
Chris Lattnerb84f3322003-12-12 21:22:16 +0000231sections. If you run into a problem, please check the <a
John Criswell86a3a482003-12-18 16:43:17 +0000232href="http://llvm.cs.uiuc.edu/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000233there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000234
Misha Brukman80731b92003-11-22 00:38:41 +0000235</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000236
Chris Lattnerb911de42004-03-14 02:03:02 +0000237<!-- ======================================================================= -->
238<div class="doc_subsection">
239 <a name="experimental">Experimental features included with this release</a>
240</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000241
Chris Lattnerb911de42004-03-14 02:03:02 +0000242<div class="doc_text">
243
Misha Brukmanfa50a222004-05-12 21:46:05 +0000244<p>The following components of this LLVM release are either untested, known to
245be broken or unreliable, or are in early development. These components should
246not be relied on, and bugs should not be filed against them, but they may be
247useful to some people. In particular, if you would like to work on one of these
248components, please contact us on the llvmdev list.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000249
250<ul>
Misha Brukman467ea6b2004-08-05 21:04:03 +0000251<li>The PowerPC backend is incomplete and is known to miscompile several SPEC
252benchmarks. The file <tt>llvm/lib/Target/PowerPC/README.txt</tt> has
253details.</li>
Chris Lattnerb911de42004-03-14 02:03:02 +0000254<li>The following passes are incomplete or buggy: <tt>-pgmdep, -memdep,
Chris Lattner09f3ac92004-09-14 16:43:13 +0000255 -ipmodref, -cee, -branch-combine, -instloops, -paths</tt></li>
Chris Lattnerb911de42004-03-14 02:03:02 +0000256<li>The <tt>-pre</tt> pass is incomplete (there are cases it doesn't handle that
257 it should) and not thoroughly tested.</li>
258<li>The <tt>llvm-ar</tt> tool is incomplete and probably buggy.</li>
259<li>The <tt>llvm-db</tt> tool is in a very early stage of development.</li>
260</ul>
261
262</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000263
Misha Brukman80731b92003-11-22 00:38:41 +0000264<!-- ======================================================================= -->
265<div class="doc_subsection">
266 <a name="core">Known problems with the LLVM Core</a>
267</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000268
Misha Brukman80731b92003-11-22 00:38:41 +0000269<div class="doc_text">
270
271<ul>
272
273<li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not
274work.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000275
276<li>The JIT does not use mutexes to protect its internal data structures. As
Misha Brukman80731b92003-11-22 00:38:41 +0000277such, execution of a threaded program could cause these data structures to be
278corrupted.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000279
Chris Lattnerc0171082004-08-08 03:33:07 +0000280<li>Linking in static archive files (.a files) is slow (there is no symbol
Misha Brukman80731b92003-11-22 00:38:41 +0000281table in the archive).</li>
Chris Lattnerc679fbb2003-11-04 20:06:53 +0000282
Misha Brukman017f2f32004-04-19 02:56:49 +0000283<li>The gccld program <a href="http://llvm.cs.uiuc.edu/PR139">does not link
284objects/archives in the order specified on the command line.</a></li>
Chris Lattneraebc66a2004-02-15 23:09:07 +0000285
286<li><a href="http://llvm.cs.uiuc.edu/PR240">The lower-invoke pass does not mark
John Criswell5d6345a2004-03-12 21:29:42 +0000287values live across a setjmp as volatile</a>. This missing feature only affects
Chris Lattneraebc66a2004-02-15 23:09:07 +0000288targets whose setjmp/longjmp libraries do not save and restore the entire
289register file.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000290</ul>
Misha Brukman80731b92003-11-22 00:38:41 +0000291</div>
292
293<!-- ======================================================================= -->
294<div class="doc_subsection">
295 <a name="c-fe">Known problems with the C front-end</a>
296</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000297
Chris Lattner3d482502003-10-02 04:57:28 +0000298<!-- _______________________________________________________________________ -->
Chris Lattner5a8a7282003-12-14 05:03:43 +0000299<div class="doc_subsubsection">Bugs</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000300
Misha Brukman80731b92003-11-22 00:38:41 +0000301<div class="doc_text">
Misha Brukman80731b92003-11-22 00:38:41 +0000302<ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000303<li>C99 Variable sized arrays do not release stack memory when they go out of
304 scope. Thus, the following program may run out of stack space:
305<pre>
306 for (i = 0; i != 1000000; ++i) {
307 int X[n];
308 foo(X);
309 }
Misha Brukman80731b92003-11-22 00:38:41 +0000310</pre></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000311
Misha Brukmanfa50a222004-05-12 21:46:05 +0000312<li>Initialization of global union variables can only be done <a
313href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=162">with the largest union
314member</a>.</li>
Chris Lattner1ab58dd2004-03-16 21:39:04 +0000315
Misha Brukman017f2f32004-04-19 02:56:49 +0000316<li><a href="http://llvm.cs.uiuc.edu/PR244">[llvm-gcc] Error when an implicitly
317external function is re-declared as static</a></li>
Chris Lattner1ab58dd2004-03-16 21:39:04 +0000318
John Criswell86a3a482003-12-18 16:43:17 +0000319</ul>
Misha Brukman80731b92003-11-22 00:38:41 +0000320</div>
321
322<!-- _______________________________________________________________________ -->
323<div class="doc_subsubsection">
324 Notes
325</div>
326
327<div class="doc_text">
328
329<ul>
330
331<li>Inline assembly is not yet supported.</li>
Chris Lattnerd2a74272003-10-27 18:30:37 +0000332
333<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman80731b92003-11-22 00:38:41 +0000334support for floating point data types of any size other than 32 and 64
335bits.</li>
336
337<li>The following Unix system functionality has not been tested and may not
338work:
Misha Brukman7cb4e382003-11-22 01:00:11 +0000339 <ol>
340 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
341 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
342 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
343 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
344 - These functions have not been tested.
345 </ol></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000346
347<li>Although many GCC extensions are supported, some are not. In particular,
348 the following extensions are known to <b>not be</b> supported:
349 <ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000350 <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 +0000351 <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>
352 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
353 <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 +0000354 <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 +0000355 <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>
356 <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 +0000357 <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>
358 <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>
359 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables.</li>
360 <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 +0000361 </ol>
Chris Lattner3d482502003-10-02 04:57:28 +0000362
Misha Brukman80731b92003-11-22 00:38:41 +0000363 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner3d482502003-10-02 04:57:28 +0000364 attribute means that the LLVM compiler ignores the presence of the attribute,
365 but the code should still work. An unsupported attribute is one which is
John Criswell86a3a482003-12-18 16:43:17 +0000366 ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman80731b92003-11-22 00:38:41 +0000367 the program.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000368
369 <ol>
370 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
371 Arrays whose length is computed at run time.<br>
Misha Brukman80731b92003-11-22 00:38:41 +0000372 Supported, but allocated stack space is not freed until the function returns (noted above).</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000373
374 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Misha Brukman80731b92003-11-22 00:38:41 +0000375
John Criswell86a3a482003-12-18 16:43:17 +0000376 Declaring that functions have no side effects or that they can never
Misha Brukman80731b92003-11-22 00:38:41 +0000377 return.<br>
378
379 <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
380 <tt>constructor</tt>, <tt>destructor</tt>, <tt>unused</tt>,
381 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
382
383 <b>Ignored:</b> <tt>noreturn</tt>, <tt>noinline</tt>,
384 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
385 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
386
387 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>,
388 <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
389 <tt>fastcall</tt>, all other target specific attributes</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000390
391 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
392 Specifying attributes of variables.<br>
393 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
394 <tt>deprecated</tt>, <tt>transparent_union</tt>,
395 <tt>unused</tt>, <tt>weak</tt><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000396
Chris Lattner3d482502003-10-02 04:57:28 +0000397 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
398 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
399 <tt>vector_size</tt>, <tt>dllimport</tt>,
Misha Brukman80731b92003-11-22 00:38:41 +0000400 <tt>dllexport</tt>, all target specific attributes.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000401
Misha Brukman8395d732003-12-12 04:37:31 +0000402 <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 +0000403 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukman8395d732003-12-12 04:37:31 +0000404 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000405
406 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
407 all target specific attributes.</li>
408
Chris Lattner3d482502003-10-02 04:57:28 +0000409 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
410 Other built-in functions.<br>
411 We support all builtins which have a C language equivalent (e.g.,
412 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
413 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Chris Lattnerb7c4bac2004-06-18 06:26:29 +0000414 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
415 (currently ignored). We also support builtins for ISO C99 floating
416 point comparison macros (e.g., <tt>__builtin_islessequal</tt>).</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000417 </ol>
Chris Lattner3d482502003-10-02 04:57:28 +0000418
Misha Brukman80731b92003-11-22 00:38:41 +0000419 <p>The following extensions <b>are</b> known to be supported:</p>
420
Chris Lattner3d482502003-10-02 04:57:28 +0000421 <ol>
Chris Lattnerd3dc8502004-03-16 08:54:07 +0000422 <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 +0000423 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
424 <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 +0000425 <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 +0000426 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
427 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
428 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
429 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
430 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
431 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
432 <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>
433 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
434 <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 +0000435 <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 +0000436 <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 +0000437 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
438or arrays as values.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000439 <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 +0000440 <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 +0000441 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
442 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
443 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
444 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized.</li>
445 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
446 <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>
447 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
448 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
449 <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>
450 <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>
451 <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 +0000452 <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 +0000453 <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>
454 <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 +0000455 </ol></li>
456
457</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000458
Misha Brukman80731b92003-11-22 00:38:41 +0000459<p>If you run into GCC extensions which have not been included in any of these
460lists, please let us know (also including whether or not they work).</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000461
Misha Brukman80731b92003-11-22 00:38:41 +0000462</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000463
Misha Brukman80731b92003-11-22 00:38:41 +0000464<!-- ======================================================================= -->
465<div class="doc_subsection">
466 <a name="c++-fe">Known problems with the C++ front-end</a>
467</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000468
Misha Brukman80731b92003-11-22 00:38:41 +0000469<div class="doc_text">
470
John Criswell86a3a482003-12-18 16:43:17 +0000471<p>For this release, the C++ front-end is considered to be fully functional but
Chris Lattnere76e9ab2003-12-12 04:25:33 +0000472has not been tested as thoroughly as the C front-end. It has been tested and
473works for a number of non-trivial programs, but there may be lurking bugs.
474Please report any bugs or problems.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000475
476</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000477
478<!-- _______________________________________________________________________ -->
Chris Lattner141ebb62004-02-14 04:12:41 +0000479<div class="doc_subsubsection">Bugs</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000480
Misha Brukman80731b92003-11-22 00:38:41 +0000481<div class="doc_text">
Chris Lattner3d482502003-10-02 04:57:28 +0000482
Misha Brukman80731b92003-11-22 00:38:41 +0000483<ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000484<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
John Criswell86a3a482003-12-18 16:43:17 +0000485 front-end</a>.</li>
Chris Lattner041e6c92004-07-17 02:04:41 +0000486
Chris Lattner5cd40922004-08-02 20:28:44 +0000487<li><b>IA-64 specific</b>: The C++ front-end does not use <a
488href="http://llvm.cs.uiuc.edu/PR406">IA64 ABI compliant layout of v-tables</a>.
Chris Lattner041e6c92004-07-17 02:04:41 +0000489In particular, it just stores function pointers instead of function
490descriptors in the vtable. This bug prevents mixing C++ code compiled with
Chris Lattner2fd93492004-08-02 20:29:51 +0000491LLVM with C++ objects compiled by other C++ compilers.</li>
Chris Lattner041e6c92004-07-17 02:04:41 +0000492
Chris Lattner5cd40922004-08-02 20:28:44 +0000493</ul>
494
Misha Brukman80731b92003-11-22 00:38:41 +0000495</div>
496
497<!-- _______________________________________________________________________ -->
498<div class="doc_subsubsection">
499 Notes
500</div>
501
502<div class="doc_text">
503
504<ul>
Chris Lattnerd2a74272003-10-27 18:30:37 +0000505
Chris Lattner3d482502003-10-02 04:57:28 +0000506<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
507parser is significantly more standards compliant (and picky) than prior GCC
508versions. For more information, see the C++ section of the <a
Chris Lattnere76e9ab2003-12-12 04:25:33 +0000509href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000510
511<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
Chris Lattner62495762003-10-02 16:38:05 +0000512 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner3d482502003-10-02 04:57:28 +0000513 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswell86a3a482003-12-18 16:43:17 +0000514 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman80731b92003-11-22 00:38:41 +0000515 better than most compilers).</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000516
Chris Lattner62495762003-10-02 16:38:05 +0000517<li>The LLVM C++ front-end follows the <a
518 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
519 This document, which is not Itanium specific, specifies a standard for name
520 mangling, class layout, v-table layout, RTTI formats, and other C++
521 representation issues. Because we use this API, code generated by the LLVM
522 compilers should be binary compatible with machine code generated by other
523 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
524 <i>However</i>, the exception handling mechanism used by LLVM is very
525 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman80731b92003-11-22 00:38:41 +0000526 interact correctly</b>. </li>
Chris Lattner3d482502003-10-02 04:57:28 +0000527
Misha Brukman80731b92003-11-22 00:38:41 +0000528</ul>
Chris Lattner46ecf612003-10-07 22:14:37 +0000529
Misha Brukman80731b92003-11-22 00:38:41 +0000530</div>
531
532<!-- ======================================================================= -->
533<div class="doc_subsection">
534 <a name="x86-be">Known problems with the X86 back-end</a>
535</div>
536
537<div class="doc_text">
538
539<ul>
Chris Lattner5cd40922004-08-02 20:28:44 +0000540 <li>none yet</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000541</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000542
Misha Brukman80731b92003-11-22 00:38:41 +0000543</div>
544
545<!-- ======================================================================= -->
546<div class="doc_subsection">
Misha Brukmana516e992004-07-12 16:55:41 +0000547 <a name="sparcv9-be">Known problems with the SparcV9 back-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000548</div>
549
550<div class="doc_text">
551
552<ul>
Misha Brukmana516e992004-07-12 16:55:41 +0000553<li><a href="http://llvm.cs.uiuc.edu/PR60">[sparcv9] SparcV9 backend miscompiles
554several programs in the LLVM test suite</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000555</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000556
Misha Brukman80731b92003-11-22 00:38:41 +0000557</div>
558
559<!-- ======================================================================= -->
560<div class="doc_subsection">
561 <a name="c-be">Known problems with the C back-end</a>
562</div>
563
564<div class="doc_text">
565
566<ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000567
568<li>The C back-end produces code that violates the ANSI C Type-Based Alias
569Analysis rules. As such, special options may be necessary to compile the code
570(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
Misha Brukman80731b92003-11-22 00:38:41 +0000571problem probably cannot be fixed.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000572
Chris Lattnera623e482003-10-20 19:05:03 +0000573<li><a href="http://llvm.cs.uiuc.edu/PR33">Initializers for global variables</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000574cannot include special floating point numbers like Not-A-Number or
575Infinity.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000576
Chris Lattnerc679fbb2003-11-04 20:06:53 +0000577<li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
Chris Lattnerb28c3282003-10-24 04:03:19 +0000578supported</a>. This should not affect LLVM produced by the C or C++
Misha Brukman80731b92003-11-22 00:38:41 +0000579frontends.</li>
Chris Lattnerb28c3282003-10-24 04:03:19 +0000580
Misha Brukman80731b92003-11-22 00:38:41 +0000581</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000582
Misha Brukman80731b92003-11-22 00:38:41 +0000583</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000584
585<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000586<div class="doc_section">
587 <a name="additionalinfo">Additional Information</a>
588</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000589<!-- *********************************************************************** -->
590
Misha Brukman80731b92003-11-22 00:38:41 +0000591<div class="doc_text">
592
593<p>A wide variety of additional information is available on the LLVM web page,
John Criswell86a3a482003-12-18 16:43:17 +0000594including mailing lists and publications describing algorithms and components
Chris Lattner3d482502003-10-02 04:57:28 +0000595implemented in LLVM. The web page also contains versions of the API
596documentation which is up-to-date with the CVS version of the source code. You
597can access versions of these documents specific to this release by going into
Misha Brukman80731b92003-11-22 00:38:41 +0000598the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000599
Misha Brukman80731b92003-11-22 00:38:41 +0000600<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerb84f3322003-12-12 21:22:16 +0000601us via the <a href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">mailing
602lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000603
Misha Brukman80731b92003-11-22 00:38:41 +0000604</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000605
606<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000607
Misha Brukman80731b92003-11-22 00:38:41 +0000608<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000609<address>
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614
Misha Brukman7cb4e382003-11-22 01:00:11 +0000615 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
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Misha Brukman68aab3b2003-11-22 01:23:39 +0000617</address>
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