blob: c7e55af3defee5f4ad43897b74b80bd3ea239ee7 [file] [log] [blame]
Misha Brukman80731b92003-11-22 00:38:41 +00001<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
3<html>
4<head>
Reid Spencere4190fa2004-11-18 18:38:58 +00005 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Misha Brukman80731b92003-11-22 00:38:41 +00006 <link rel="stylesheet" href="llvm.css" type="text/css">
Chris Lattner98a33492007-05-09 04:58:11 +00007 <title>LLVM 2.0 Release Notes</title>
Misha Brukman80731b92003-11-22 00:38:41 +00008</head>
9<body>
Chris Lattner3d482502003-10-02 04:57:28 +000010
Chris Lattner98a33492007-05-09 04:58:11 +000011<div class="doc_title">LLVM 2.0 Release Notes</div>
Chris Lattner3d482502003-10-02 04:57:28 +000012
13<ol>
Misha Brukman80731b92003-11-22 00:38:41 +000014 <li><a href="#intro">Introduction</a></li>
15 <li><a href="#whatsnew">What's New?</a></li>
Chris Lattner77a51732004-04-30 22:17:12 +000016 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +000017 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +000018 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman80731b92003-11-22 00:38:41 +000019 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +000020</ol>
21
Chris Lattner020e1fc2004-05-23 21:07:27 +000022<div class="doc_author">
Chris Lattnera69595e2005-10-29 07:07:09 +000023 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
Misha Brukman80731b92003-11-22 00:38:41 +000024</div>
Chris Lattner3d482502003-10-02 04:57:28 +000025
26<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +000027<div class="doc_section">
28 <a name="intro">Introduction</a>
29</div>
Chris Lattner3d482502003-10-02 04:57:28 +000030<!-- *********************************************************************** -->
31
Misha Brukman80731b92003-11-22 00:38:41 +000032<div class="doc_text">
33
34<p>This document contains the release notes for the LLVM compiler
Chris Lattner98a33492007-05-09 04:58:11 +000035infrastructure, release 2.0. Here we describe the status of LLVM, including any
36known problems and major improvements from the previous release. All LLVM
37releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
38releases web site</a>.
Chris Lattner62495762003-10-02 16:38:05 +000039
Chris Lattnerb5bb5972004-12-07 08:04:13 +000040<p>For more information about LLVM, including information about the latest
Chris Lattnera69595e2005-10-29 07:07:09 +000041release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattnere7525b52003-10-07 21:38:31 +000042web site</a>. If you have questions or comments, the <a
43href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman80731b92003-11-22 00:38:41 +000044list</a> is a good place to send them.</p>
Chris Lattner3d482502003-10-02 04:57:28 +000045
Chris Lattnerf3a7c242004-12-09 22:22:58 +000046<p>Note that if you are reading this file from CVS or the main LLVM web page,
47this document applies to the <i>next</i> release, not the current one. To see
48the release notes for the current or previous releases, see the <a
Chris Lattnera69595e2005-10-29 07:07:09 +000049href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman80731b92003-11-22 00:38:41 +000050
51</div>
Chris Lattner3d482502003-10-02 04:57:28 +000052
53<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +000054<div class="doc_section">
55 <a name="whatsnew">What's New?</a>
56</div>
Chris Lattner3d482502003-10-02 04:57:28 +000057<!-- *********************************************************************** -->
58
Misha Brukman80731b92003-11-22 00:38:41 +000059<div class="doc_text">
60
Chris Lattner98a33492007-05-09 04:58:11 +000061<p>This is the eleventh public release of the LLVM Compiler Infrastructure.
Chris Lattner2d47f922007-05-09 05:27:05 +000062Being the first major release since 1.0, this release is different in several
63ways from our previous releases:</p>
64
65<ol>
66<li>We took this as an opportunity to
Chris Lattner98a33492007-05-09 04:58:11 +000067break backwards compatibility with the LLVM 1.x bytecode and .ll file format.
68If you have LLVM 1.9 .ll files that you would like to upgrade to LLVM 2.x, we
69recommend the use of the stand alone <a href=#llvm-upgrade">llvm-upgrade</a>
70tool. We intend to keep compatibility with .ll and .bc formats within the 2.x
Chris Lattner2d47f922007-05-09 05:27:05 +000071release series, like we did within the 1.x series.</li>
72<li>There are several significant change to the LLVM IR and internal APIs, such
73 as a major overhaul of the type system, the completely new bitcode file
74 format, etc.</li>
75<li>We designed the release around a 6 month release cycle instead of the usual
76 3-month cycle. This gave us extra time to develop and test some of the
77 more invasive features in this release.</li>
78<li>LLVM 2.0 no longer supports the llvm-gcc3 front-end.</li>
79</ol>
Chris Lattner98a33492007-05-09 04:58:11 +000080
Chris Lattner2d47f922007-05-09 05:27:05 +000081<p>Note that while this is a major version bump, this release has been
82 extensively tested on a wide range of software. It is easy to say that this
83 is our best release yet, in terms of both features and correctness.</p>
Chris Lattnerba7bd472003-12-06 20:22:41 +000084
Chris Lattner21a90402004-05-24 04:50:25 +000085</div>
86
Chris Lattnerba7bd472003-12-06 20:22:41 +000087<!--=========================================================================-->
Chris Lattner406bddf2005-05-15 05:44:51 +000088<div class="doc_subsection">
Chris Lattner98a33492007-05-09 04:58:11 +000089<a name="newfeatures">New Features in LLVM 2.0</a>
Chris Lattner9f871732006-04-18 06:18:36 +000090</div>
91
Chris Lattner89e761c2006-04-18 06:32:08 +000092<!--_________________________________________________________________________-->
Chris Lattnerb81f10e2006-11-18 07:51:14 +000093<div class="doc_subsubsection"><a name="optimizer">Optimizer
94Improvements</a></div>
Chris Lattner89e761c2006-04-18 06:32:08 +000095<div class="doc_text">
Chris Lattnerb81f10e2006-11-18 07:51:14 +000096<p>The mid-level optimizer is now faster and produces better code in many cases.
97 Significant changes include:</p>
98
99<ul>
Chris Lattner98a33492007-05-09 04:58:11 +0000100<li></li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000101</ul>
102
Chris Lattner89e761c2006-04-18 06:32:08 +0000103</div>
104
Chris Lattner0b7fd712006-04-19 04:02:47 +0000105<!--_________________________________________________________________________-->
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000106<div class="doc_subsubsection"><a name="codegen">Code
107Generator Enhancements</a></div>
108
Chris Lattner0b7fd712006-04-19 04:02:47 +0000109<div class="doc_text">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000110<p>
111The LLVM Target-Independent code generator now supports more target features and
112optimizes many cases more aggressively. New features include:
113</p>
114
115<ul>
Chris Lattner98a33492007-05-09 04:58:11 +0000116<li></li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000117</ul>
118
119<p>In addition, the LLVM target description format has itself been extended in
120 several ways:</p>
121
122<ul>
Chris Lattner98a33492007-05-09 04:58:11 +0000123<li></li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000124</ul>
125
126<p>Further, several significant target-specific enhancements are included in
Chris Lattner98a33492007-05-09 04:58:11 +0000127LLVM 2.0:</p>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000128
129<ul>
Chris Lattner98a33492007-05-09 04:58:11 +0000130<li></li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000131</ul>
132
Chris Lattner0b7fd712006-04-19 04:02:47 +0000133</div>
Chris Lattner9f871732006-04-18 06:18:36 +0000134
135<!--_________________________________________________________________________-->
Chris Lattner44124232006-08-08 17:27:28 +0000136<div class="doc_subsubsection"><a name="other">Other Improvements</a></div>
Chris Lattnera38fe5f2006-02-05 06:39:36 +0000137<div class="doc_text">
Chris Lattner98a33492007-05-09 04:58:11 +0000138<p></p>
Chris Lattner44124232006-08-08 17:27:28 +0000139
140<p>More specific changes include:</p>
141
Chris Lattnera38fe5f2006-02-05 06:39:36 +0000142<ul>
Chris Lattner98a33492007-05-09 04:58:11 +0000143<li></li>
Chris Lattnera38fe5f2006-02-05 06:39:36 +0000144</ul>
145</div>
John Criswell51e2a482005-06-29 16:22:34 +0000146
Chris Lattner72a269f2006-03-03 00:34:26 +0000147
148
Chris Lattner62495762003-10-02 16:38:05 +0000149<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000150<div class="doc_section">
151 <a name="portability">Portability and Supported Platforms</a>
152</div>
Chris Lattner62495762003-10-02 16:38:05 +0000153<!-- *********************************************************************** -->
154
Misha Brukman80731b92003-11-22 00:38:41 +0000155<div class="doc_text">
156
John Criswell64307722004-12-08 20:35:47 +0000157<p>LLVM is known to work on the following platforms:</p>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000158
159<ul>
Reid Spencer9803b402005-05-17 02:47:27 +0000160 <li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
161 (and probably other unix-like systems).</li>
Chris Lattner4d918bb2006-08-09 04:10:32 +0000162<li>Intel and AMD machines running on Win32 using MinGW libraries (native)</li>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000163<li>Sun UltraSPARC workstations running Solaris 8.</li>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000164<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
165 support is available for native builds with Visual C++).</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000166<li>PowerPC and X86-based Mac OS X systems, running 10.2 and above in 32-bit and
167 64-bit modes.</li>
John Criswelld5234922005-05-13 20:28:15 +0000168<li>Alpha-based machines running Debian GNU/Linux.</li>
169<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000170</ul>
171
Brian Gaekee3e557e2004-05-09 05:28:35 +0000172<p>The core LLVM infrastructure uses
173<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
174to the machine and operating system on which it is built. However, minor
175porting may be required to get LLVM to work on new platforms. We welcome your
176portability patches and reports of successful builds or error messages.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000177
Misha Brukman80731b92003-11-22 00:38:41 +0000178</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000179
180<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000181<div class="doc_section">
182 <a name="knownproblems">Known Problems</a>
183</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000184<!-- *********************************************************************** -->
185
Misha Brukman80731b92003-11-22 00:38:41 +0000186<div class="doc_text">
187
188<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner3d482502003-10-02 04:57:28 +0000189component. As new problems are discovered, they will be added to these
Chris Lattnerb84f3322003-12-12 21:22:16 +0000190sections. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000191href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000192there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000193
Misha Brukman80731b92003-11-22 00:38:41 +0000194</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000195
Chris Lattnerb911de42004-03-14 02:03:02 +0000196<!-- ======================================================================= -->
197<div class="doc_subsection">
198 <a name="experimental">Experimental features included with this release</a>
199</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000200
Chris Lattnerb911de42004-03-14 02:03:02 +0000201<div class="doc_text">
202
Misha Brukmanfa50a222004-05-12 21:46:05 +0000203<p>The following components of this LLVM release are either untested, known to
204be broken or unreliable, or are in early development. These components should
205not be relied on, and bugs should not be filed against them, but they may be
206useful to some people. In particular, if you would like to work on one of these
Chris Lattner05a225b2006-08-09 04:08:52 +0000207components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000208
209<ul>
Chris Lattner9f871732006-04-18 06:18:36 +0000210<li>The <tt>-cee</tt> pass is known to be buggy, and may be removed in in a
211 future release.</li>
Chris Lattnerc9757932007-05-09 06:23:58 +0000212<li>C++ EH support</li>
Chris Lattnera38fe5f2006-02-05 06:39:36 +0000213<li>The IA64 code generator is experimental.</li>
Chris Lattnera69595e2005-10-29 07:07:09 +0000214<li>The Alpha JIT is experimental.</li>
Chris Lattner9f871732006-04-18 06:18:36 +0000215<li>"<tt>-filetype=asm</tt>" (the default) is the only supported value for the
216 <tt>-filetype</tt> llc option.</li>
Chris Lattnerb911de42004-03-14 02:03:02 +0000217</ul>
218
219</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000220
Misha Brukman80731b92003-11-22 00:38:41 +0000221<!-- ======================================================================= -->
222<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000223 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswell3bdbd302005-11-08 21:11:33 +0000224</div>
225
226<div class="doc_text">
227
228<ul>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000229<li>The X86 backend does not yet support <a href="http://llvm.org/PR879">inline
Chris Lattner98a33492007-05-09 04:58:11 +0000230 assembly that uses the X86 floating point stack</a>.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000231</ul>
232
233</div>
234
235<!-- ======================================================================= -->
236<div class="doc_subsection">
237 <a name="ppc-be">Known problems with the PowerPC back-end</a>
238</div>
239
240<div class="doc_text">
241
242<ul>
243<li><a href="http://llvm.org/PR642">PowerPC backend does not correctly
244implement ordered FP comparisons</a>.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000245</ul>
246
247</div>
248
249<!-- ======================================================================= -->
250<div class="doc_subsection">
251 <a name="sparc-be">Known problems with the SPARC back-end</a>
252</div>
253
254<div class="doc_text">
255
256<ul>
257<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
258 support the 64-bit SPARC ABI (-m64).</li>
259</ul>
260
261</div>
262
263<!-- ======================================================================= -->
264<div class="doc_subsection">
265 <a name="c-be">Known problems with the C back-end</a>
266</div>
267
268<div class="doc_text">
269
270<ul>
271
272<li>The C back-end produces code that violates the ANSI C Type-Based Alias
273Analysis rules. As such, special options may be necessary to compile the code
274(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
275problem probably cannot be fixed.</li>
276
277<li><a href="http://llvm.org/PR56">Zero arg vararg functions are not
278supported</a>. This should not affect LLVM produced by the C or C++
279frontends.</li>
280
281<li>The C backend does not correctly implement the <a
Reid Spencerca5fdf32007-04-04 04:14:31 +0000282href="LangRef.html#int_stacksave"><tt>llvm.stacksave</tt></a> or
283<a href="LangRef.html#int_stackrestore"><tt>llvm.stackrestore</tt></a>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000284intrinsics. This means that some code compiled by it can run out of stack
285space if they depend on these (e.g. C99 varargs).</li>
286
287<li><a href="http://llvm.org/PR802">The C backend does not support inline
288 assembly code</a>.</li>
289</ul>
290
291</div>
292
293<!-- ======================================================================= -->
294<div class="doc_subsection">
295 <a name="alpha-be">Known problems with the Alpha back-end</a>
296</div>
297
298<div class="doc_text">
299
300<ul>
301
302<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
303appropriate nops inserted to ensure restartability.</li>
304
John Criswell3bdbd302005-11-08 21:11:33 +0000305</ul>
306</div>
307
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000308<!-- ======================================================================= -->
309<div class="doc_subsection">
310 <a name="ia64-be">Known problems with the IA64 back-end</a>
311</div>
312
313<div class="doc_text">
314
315<ul>
316
317<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
318made where the argument is not 16-byte aligned, as required on IA64. (Strictly
319speaking this is not a bug in the IA64 back-end; it will also be encountered
320when building C++ programs using the C back-end.)</li>
321
322<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
323ABI compliant layout of v-tables</a>. In particular, it just stores function
324pointers instead of function descriptors in the vtable. This bug prevents
325mixing C++ code compiled with LLVM with C++ objects compiled by other C++
326compilers.</li>
327
328<li>There are a few ABI violations which will lead to problems when mixing LLVM
329output with code built with other compilers, particularly for floating-point
330programs.</li>
331
332<li>Defining vararg functions is not supported (but calling them is ok).</li>
333
Chris Lattner98a33492007-05-09 04:58:11 +0000334<li>The Itanium backend has bitrotted somewhat.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000335</ul>
336
337</div>
338
339<!-- ======================================================================= -->
340<div class="doc_subsection">
341 <a name="arm-be">Known problems with the ARM back-end</a>
342</div>
343
344<div class="doc_text">
345
346<ul>
347<li>The ARM backend is currently in early development stages, it is not
348ready for production use.</li>
349</ul>
350
351</div>
John Criswell3bdbd302005-11-08 21:11:33 +0000352
353<!-- ======================================================================= -->
354<div class="doc_subsection">
Misha Brukman80731b92003-11-22 00:38:41 +0000355 <a name="core">Known problems with the LLVM Core</a>
356</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000357
Misha Brukman80731b92003-11-22 00:38:41 +0000358<div class="doc_text">
359
360<ul>
Misha Brukman96158092005-03-30 19:14:24 +0000361 <li>In the JIT, <tt>dlsym()</tt> on a symbol compiled by the JIT will not
362 work.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000363</ul>
Misha Brukman80731b92003-11-22 00:38:41 +0000364</div>
365
366<!-- ======================================================================= -->
367<div class="doc_subsection">
368 <a name="c-fe">Known problems with the C front-end</a>
369</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000370
Chris Lattner3d482502003-10-02 04:57:28 +0000371<!-- _______________________________________________________________________ -->
Chris Lattner5a8a7282003-12-14 05:03:43 +0000372<div class="doc_subsubsection">Bugs</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000373
Misha Brukman80731b92003-11-22 00:38:41 +0000374<div class="doc_text">
Chris Lattner72a269f2006-03-03 00:34:26 +0000375
Chris Lattner9f871732006-04-18 06:18:36 +0000376<p>
Chris Lattner44124232006-08-08 17:27:28 +0000377
378<p>llvm-gcc4 is far more stable and produces better code than llvm-gcc3, but
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000379does not currently support <a href="http://llvm.org/PR869">Link-Time
380Optimization</a> or <a href="http://llvm.org/PR870">C++ Exception Handling</a>,
Chris Lattner44124232006-08-08 17:27:28 +0000381which llvm-gcc3 does.</p>
382
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000383<p>llvm-gcc4 does not support the <a href="http://llvm.org/PR947">GCC indirect
384goto extension</a>, but llvm-gcc3 does.</p>
385
Misha Brukman80731b92003-11-22 00:38:41 +0000386</div>
387
388<!-- _______________________________________________________________________ -->
389<div class="doc_subsubsection">
390 Notes
391</div>
392
393<div class="doc_text">
394
395<ul>
396
Chris Lattnerd2a74272003-10-27 18:30:37 +0000397<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman80731b92003-11-22 00:38:41 +0000398support for floating point data types of any size other than 32 and 64
399bits.</li>
400
Chris Lattner3d482502003-10-02 04:57:28 +0000401<li>Although many GCC extensions are supported, some are not. In particular,
402 the following extensions are known to <b>not be</b> supported:
403 <ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000404 <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 +0000405 <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>
406 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
Tanya Lattner63371342004-12-08 18:25:34 +0000407 <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 +0000408 <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 +0000409 </ol>
Chris Lattner3d482502003-10-02 04:57:28 +0000410
Misha Brukman80731b92003-11-22 00:38:41 +0000411 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner3d482502003-10-02 04:57:28 +0000412 attribute means that the LLVM compiler ignores the presence of the attribute,
413 but the code should still work. An unsupported attribute is one which is
John Criswell86a3a482003-12-18 16:43:17 +0000414 ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman80731b92003-11-22 00:38:41 +0000415 the program.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000416
417 <ol>
418 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
419 Arrays whose length is computed at run time.<br>
Misha Brukman80731b92003-11-22 00:38:41 +0000420 Supported, but allocated stack space is not freed until the function returns (noted above).</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000421
422 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Misha Brukman80731b92003-11-22 00:38:41 +0000423
John Criswell86a3a482003-12-18 16:43:17 +0000424 Declaring that functions have no side effects or that they can never
Misha Brukman80731b92003-11-22 00:38:41 +0000425 return.<br>
426
Anton Korobeynikove7cbbfc2006-11-18 08:04:48 +0000427 <b>Supported:</b> <tt>constructor</tt>, <tt>destructor</tt>,
428 <tt>deprecated</tt>, <tt>fastcall</tt>, <tt>format</tt>,
429 <tt>format_arg</tt>, <tt>non_null</tt>, <tt>noreturn</tt>,
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000430 <tt>section</tt>, <tt>stdcall</tt>, <tt>unused</tt>, <tt>used</tt>,
431 <tt>visibility</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000432
John Criswell64307722004-12-08 20:35:47 +0000433 <b>Ignored:</b> <tt>noinline</tt>,
Misha Brukman80731b92003-11-22 00:38:41 +0000434 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
435 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
436
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000437 <b>Unsupported:</b> <tt>alias</tt>, <tt>regparm</tt>, all other target specific
Anton Korobeynikove7cbbfc2006-11-18 08:04:48 +0000438 attributes</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000439
440 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
441 Specifying attributes of variables.<br>
442 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000443 <tt>deprecated</tt>, <tt>dllimport</tt>, <tt>dllexport</tt>,
444 <tt>section</tt>, <tt>transparent_union</tt>, <tt>unused</tt>,
445 <tt>used</tt>, <tt>weak</tt><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000446
Chris Lattner3d482502003-10-02 04:57:28 +0000447 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000448 <tt>shared</tt>, <tt>tls_model</tt>,
449 <tt>vector_size</tt>, all target specific attributes.
Anton Korobeynikove7cbbfc2006-11-18 08:04:48 +0000450 </li>
Chris Lattner3d482502003-10-02 04:57:28 +0000451
Misha Brukman8395d732003-12-12 04:37:31 +0000452 <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 +0000453 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukman8395d732003-12-12 04:37:31 +0000454 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000455
456 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
457 all target specific attributes.</li>
458
Chris Lattner3d482502003-10-02 04:57:28 +0000459 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
460 Other built-in functions.<br>
461 We support all builtins which have a C language equivalent (e.g.,
462 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
463 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Chris Lattnerb7c4bac2004-06-18 06:26:29 +0000464 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
465 (currently ignored). We also support builtins for ISO C99 floating
Chris Lattnerb34b2732005-05-07 02:21:21 +0000466 point comparison macros (e.g., <tt>__builtin_islessequal</tt>),
467 <tt>__builtin_prefetch</tt>, <tt>__builtin_popcount[ll]</tt>,
468 <tt>__builtin_clz[ll]</tt>, and <tt>__builtin_ctz[ll]</tt>.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000469 </ol>
Chris Lattner3d482502003-10-02 04:57:28 +0000470
Misha Brukman80731b92003-11-22 00:38:41 +0000471 <p>The following extensions <b>are</b> known to be supported:</p>
472
Chris Lattner3d482502003-10-02 04:57:28 +0000473 <ol>
Chris Lattnerd3dc8502004-03-16 08:54:07 +0000474 <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 +0000475 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
476 <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 +0000477 <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 +0000478 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
479 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
480 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
481 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
482 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
483 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
484 <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>
485 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000486 <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>
487 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
488 <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>
489 <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>
490 <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>
491 <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>
Misha Brukman80731b92003-11-22 00:38:41 +0000492 <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 +0000493 <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 +0000494 <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 +0000495 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
496or arrays as values.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000497 <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 +0000498 <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 +0000499 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
500 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
501 <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 +0000502 <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 +0000503 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
504 <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>
505 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
506 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
507 <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>
508 <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>
509 <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 +0000510 <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 +0000511 <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>
512 <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 +0000513 </ol></li>
514
515</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000516
Misha Brukman80731b92003-11-22 00:38:41 +0000517<p>If you run into GCC extensions which have not been included in any of these
518lists, please let us know (also including whether or not they work).</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000519
Misha Brukman80731b92003-11-22 00:38:41 +0000520</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000521
Misha Brukman80731b92003-11-22 00:38:41 +0000522<!-- ======================================================================= -->
523<div class="doc_subsection">
524 <a name="c++-fe">Known problems with the C++ front-end</a>
525</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000526
Misha Brukman80731b92003-11-22 00:38:41 +0000527<div class="doc_text">
528
Reid Spencer55684c32004-12-07 08:39:08 +0000529<p>For this release, the C++ front-end is considered to be fully
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000530tested and works for a number of non-trivial programs, including LLVM
531itself.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000532
533</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000534
535<!-- _______________________________________________________________________ -->
Misha Brukman80731b92003-11-22 00:38:41 +0000536<div class="doc_subsubsection">
537 Notes
538</div>
539
540<div class="doc_text">
Misha Brukman80731b92003-11-22 00:38:41 +0000541<ul>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000542<li>llvm-gcc4 does not support C++ exception handling at all yet.</li>
Chris Lattnerd2a74272003-10-27 18:30:37 +0000543
Chris Lattner3d482502003-10-02 04:57:28 +0000544<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
Chris Lattner62495762003-10-02 16:38:05 +0000545 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner3d482502003-10-02 04:57:28 +0000546 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswell86a3a482003-12-18 16:43:17 +0000547 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman80731b92003-11-22 00:38:41 +0000548 better than most compilers).</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000549
Chris Lattner62495762003-10-02 16:38:05 +0000550<li>The LLVM C++ front-end follows the <a
551 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
552 This document, which is not Itanium specific, specifies a standard for name
553 mangling, class layout, v-table layout, RTTI formats, and other C++
554 representation issues. Because we use this API, code generated by the LLVM
555 compilers should be binary compatible with machine code generated by other
556 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000557 <i>However</i>, the exception handling mechanism used by llvm-gcc3 is very
Chris Lattner62495762003-10-02 16:38:05 +0000558 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman80731b92003-11-22 00:38:41 +0000559 interact correctly</b>. </li>
Chris Lattner3d482502003-10-02 04:57:28 +0000560
Misha Brukman80731b92003-11-22 00:38:41 +0000561</ul>
Chris Lattner46ecf612003-10-07 22:14:37 +0000562
Misha Brukman80731b92003-11-22 00:38:41 +0000563</div>
564
Misha Brukman80731b92003-11-22 00:38:41 +0000565
Chris Lattnerb62a5f02005-05-15 16:01:20 +0000566
Chris Lattner3d482502003-10-02 04:57:28 +0000567<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000568<div class="doc_section">
569 <a name="additionalinfo">Additional Information</a>
570</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000571<!-- *********************************************************************** -->
572
Misha Brukman80731b92003-11-22 00:38:41 +0000573<div class="doc_text">
574
Chris Lattnercb5596d2005-05-16 17:13:10 +0000575<p>A wide variety of additional information is available on the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000576href="http://llvm.org">LLVM web page</a>, including <a
577href="http://llvm.org/docs/">documentation</a> and <a
578href="http://llvm.org/pubs/">publications describing algorithms and
Misha Brukman96158092005-03-30 19:14:24 +0000579components implemented in LLVM</a>. The web page also contains versions of the
580API documentation which is up-to-date with the CVS version of the source code.
581You can access versions of these documents specific to this release by going
582into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000583
Misha Brukman80731b92003-11-22 00:38:41 +0000584<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnera69595e2005-10-29 07:07:09 +0000585us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000586lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000587
Misha Brukman80731b92003-11-22 00:38:41 +0000588</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000589
590<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000591
Misha Brukman80731b92003-11-22 00:38:41 +0000592<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000593<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000594 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman68aab3b2003-11-22 01:23:39 +0000595 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
596 <a href="http://validator.w3.org/check/referer"><img
597 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
598
Chris Lattnera69595e2005-10-29 07:07:09 +0000599 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000600 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000601</address>
Chris Lattner3d482502003-10-02 04:57:28 +0000602
Misha Brukman80731b92003-11-22 00:38:41 +0000603</body>
604</html>