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Chris Lattner000c73b2008-02-06 06:30:34 +00007 <title>LLVM 2.2 Release Notes</title>
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9<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +000010
Chris Lattner000c73b2008-02-06 06:30:34 +000011<div class="doc_title">LLVM 2.2 Release Notes</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000012
13<ol>
Misha Brukman500bc302003-11-22 00:38:41 +000014 <li><a href="#intro">Introduction</a></li>
15 <li><a href="#whatsnew">What's New?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +000016 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +000017 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +000018 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman500bc302003-11-22 00:38:41 +000019 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +000020</ol>
21
Chris Lattner7911ce22004-05-23 21:07:27 +000022<div class="doc_author">
Chris Lattnerc463b272005-10-29 07:07:09 +000023 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
Misha Brukman500bc302003-11-22 00:38:41 +000024</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000025
Chris Lattner052bae62008-02-06 18:00:48 +000026<h1><font color="red">THIS IS A WORK IN PROGRESS FOR THE LLVM 2.2
27RELEASE</font</h1>
28
Chris Lattner79c3fe12003-10-02 04:57:28 +000029<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +000030<div class="doc_section">
31 <a name="intro">Introduction</a>
32</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000033<!-- *********************************************************************** -->
34
Misha Brukman500bc302003-11-22 00:38:41 +000035<div class="doc_text">
36
37<p>This document contains the release notes for the LLVM compiler
Chris Lattner000c73b2008-02-06 06:30:34 +000038infrastructure, release 2.2. Here we describe the status of LLVM, including
Chris Lattner57a460e2007-05-23 04:39:32 +000039major improvements from the previous release and any known problems. All LLVM
Chris Lattnercaf06342007-05-09 04:58:11 +000040releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
Chris Lattner57a460e2007-05-23 04:39:32 +000041releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +000042
Chris Lattner7506b1d2004-12-07 08:04:13 +000043<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +000044release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +000045web site</a>. If you have questions or comments, the <a
46href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman500bc302003-11-22 00:38:41 +000047list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +000048
Reid Spencer669ed452007-07-09 08:04:31 +000049<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner84977642007-09-21 03:54:09 +000050main LLVM web page, this document applies to the <i>next</i> release, not the
51current one. To see the release notes for a specific releases, please see the
52<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +000053
54</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000055
56<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +000057<div class="doc_section">
58 <a name="whatsnew">What's New?</a>
59</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000060<!-- *********************************************************************** -->
61
Misha Brukman500bc302003-11-22 00:38:41 +000062<div class="doc_text">
63
Chris Lattner000c73b2008-02-06 06:30:34 +000064<p>This is the thirteenth public release of the LLVM Compiler Infrastructure.
65It includes many features and refinements from LLVM 2.1.</p>
Chris Lattnera5099962003-12-06 20:22:41 +000066
Chris Lattner80453c92004-05-24 04:50:25 +000067</div>
68
Chris Lattnera5099962003-12-06 20:22:41 +000069<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +000070<div class="doc_subsection">
Chris Lattner000c73b2008-02-06 06:30:34 +000071<a name="frontends">llvm-gcc 4.0, llvm-gcc 4.2, and clang</a>
Chris Lattner44c933e2006-04-18 06:18:36 +000072</div>
73
Chris Lattnerf3e5bc62007-05-14 06:56:09 +000074<div class="doc_text">
Chris Lattner60893e52007-05-18 06:33:02 +000075
Chris Lattner000c73b2008-02-06 06:30:34 +000076<p>LLVM 2.2 fully supports both the llvm-gcc 4.0 and llvm-gcc 4.2 front-ends (in
77LLVM 2.1, llvm-gcc 4.2 was beta). Since LLVM 2.1, the llvm-gcc 4.2 front-end
78has made leaps and bounds and is now at least as good as 4.0 in virtually every
79area, and is better in several areas (for example, exception handling
80correctness). We strongly recommend that you migrate from llvm-gcc 4.0 to
81llvm-gcc 4.2 in this release cycle because <b>LLVM 2.2 is the last release
82that will support llvm-gcc 4.0</b>: LLVM 2.3 will only support the llvm-gcc
834.2 front-end.</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +000084
Chris Lattner252b83d2008-02-06 18:00:06 +000085<p>The <a href="http://clang.llvm.org/">clang project</a> is an effort to build
86a set of new 'llvm native' front-end technologies for the LLVM optimizer
87and code generator. Currently, its C and Objective-C support is maturing
88nicely, and it has advanced source-to-source analysis and transformation
89capabilities. If you are interested in building source-level tools for C and
90Objective-C (and eventually C++), you should take a look. However, note that
91clang is not an official part of the LLVM 2.2 release. If you are interested in
92this project, please see the web site.</p>
93
94</div>
95
96<!--=========================================================================-->
97<div class="doc_subsection">
98<a name="majorfeatures">Major New Features</a>
99</div>
100
101<div class="doc_text">
102
103<p>Dale contributed full support for long double on x86/x86-64 (where it is 80
104bits) and on Darwin PPC/PPC64 (where it is 128 bits).</p>
105
106<p>Ada, gfortran</p>
107
108<p>
109debug improvements -O0
110EH.
111
112Gordon: GC Revamp. docs/GarbageCollection.html
113
114Kaleidescope: docs/tutorial
115
116Gordon: C and Ocaml Bindings
Chris Lattner60893e52007-05-18 06:33:02 +0000117
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000118</div>
119
Chris Lattner84977642007-09-21 03:54:09 +0000120<!--=========================================================================-->
121<div class="doc_subsection">
122<a name="optimizer">Optimizer Improvements</a>
123</div>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000124
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000125<div class="doc_text">
Chris Lattner84977642007-09-21 03:54:09 +0000126
Chris Lattnerd4298712007-09-26 05:44:21 +0000127<p>Some of the most noticable feature improvements this release have been in the
128optimizer, speeding it up and making it more aggressive. For example:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000129
130<ul>
Tanya Lattnerb6ec3a92007-05-16 23:25:46 +0000131
Chris Lattner6b1a4ec2008-02-06 18:32:06 +0000132<li>Daniel Berlin and (Curtis?) rewrote Andersen's alias analysis (which is not
Chris Lattner252b83d2008-02-06 18:00:06 +0000133enabled by default) to be several orders of magnitude faster, implmented Offline
134Variable Substitution.</li>
Tanya Lattnerb6ec3a92007-05-16 23:25:46 +0000135
Chris Lattner252b83d2008-02-06 18:00:06 +0000136
137Devang: LoopIndexSplit is enabled by default.
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000138</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000139
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000140</div>
141
Chris Lattner84977642007-09-21 03:54:09 +0000142<!--=========================================================================-->
143<div class="doc_subsection">
144<a name="codegen">Code Generator Improvements</a>
145</div>
146
147<div class="doc_text">
148
Chris Lattner252b83d2008-02-06 18:00:06 +0000149<p>foci of this release was performance tuning and bug
Chris Lattnerd4298712007-09-26 05:44:21 +0000150 fixing. In addition to these, several new major changes occurred:</p>
151
Chris Lattner84977642007-09-21 03:54:09 +0000152<ul>
153
Chris Lattner6b1a4ec2008-02-06 18:32:06 +0000154<li>Owen contributed Machine Loop info, domintors, etc. Merged dom and
155 postdom.</li>
Chris Lattner84977642007-09-21 03:54:09 +0000156
Chris Lattner252b83d2008-02-06 18:00:06 +0000157<li>Dan added support for emitting debug information with .file and .loc on
158targets that support it</li>
159
160<li>Evan physical register dependencies in the BURR scheduler</li>
Chris Lattner6b1a4ec2008-02-06 18:32:06 +0000161
162<li>Evan EXTRACT_SUBREG coalescing support</li>
Chris Lattner84977642007-09-21 03:54:09 +0000163</ul>
164
165</div>
166
167
168<!--=========================================================================-->
169<div class="doc_subsection">
170<a name="targetspecific">Target Specific Improvements</a>
171</div>
Chris Lattner60893e52007-05-18 06:33:02 +0000172
Chris Lattner738bd302006-04-18 06:32:08 +0000173<div class="doc_text">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000174<p>New features include:
175</p>
Chris Lattner26299222006-11-18 07:51:14 +0000176
177<ul>
Chris Lattner252b83d2008-02-06 18:00:06 +0000178<li>Evan X86 now models EFLAGS in instructions.</li>
179<li>Evan: If conversion on by default for ARM.</li>
Chris Lattner6b1a4ec2008-02-06 18:32:06 +0000180<li>Bruno: MIPS PIC support.</li>
181<li>Arnold Schwaighofer: X86 tail call support.</li>
Chris Lattner84977642007-09-21 03:54:09 +0000182</ul>
183
184</div>
Chris Lattner57a460e2007-05-23 04:39:32 +0000185
Chris Lattner57a460e2007-05-23 04:39:32 +0000186
Chris Lattner84977642007-09-21 03:54:09 +0000187<!--=========================================================================-->
188<div class="doc_subsection">
189<a name="llvmgccimprovements">llvm-gcc Improvements</a>
190</div>
Tanya Lattnerb6ec3a92007-05-16 23:25:46 +0000191
Chris Lattner84977642007-09-21 03:54:09 +0000192<div class="doc_text">
193<p>New features include:
194</p>
Tanya Lattnerb6ec3a92007-05-16 23:25:46 +0000195
Chris Lattner84977642007-09-21 03:54:09 +0000196<ul>
Chris Lattner000c73b2008-02-06 06:30:34 +0000197<li>.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000198</ul>
199
Chris Lattner738bd302006-04-18 06:32:08 +0000200</div>
201
Chris Lattner84977642007-09-21 03:54:09 +0000202
203<!--=========================================================================-->
204<div class="doc_subsection">
205<a name="coreimprovements">LLVM Core Improvements</a>
206</div>
Chris Lattner26299222006-11-18 07:51:14 +0000207
Chris Lattner1c1a85c2006-04-19 04:02:47 +0000208<div class="doc_text">
Chris Lattner84977642007-09-21 03:54:09 +0000209<p>New features include:
Chris Lattner26299222006-11-18 07:51:14 +0000210</p>
211
212<ul>
Chris Lattner6b1a4ec2008-02-06 18:32:06 +0000213<li>Devang added LLVMFoldingBuilder.</li>
214<li>Dan added support for vector sin, cos, and pow intrinsics.</li>
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000215</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000216
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000217</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000218
Chris Lattner84977642007-09-21 03:54:09 +0000219<!--=========================================================================-->
220<div class="doc_subsection">
221<a name="otherimprovements">Other Improvements</a>
222</div>
223
224<div class="doc_text">
225<p>New features include:
226</p>
227
228<ul>
Chris Lattner000c73b2008-02-06 06:30:34 +0000229<li>.</li>
Chris Lattner84977642007-09-21 03:54:09 +0000230</ul>
231
232</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000233
Chris Lattner19092612003-10-02 16:38:05 +0000234<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000235<div class="doc_section">
236 <a name="portability">Portability and Supported Platforms</a>
237</div>
Chris Lattner19092612003-10-02 16:38:05 +0000238<!-- *********************************************************************** -->
239
Misha Brukman500bc302003-11-22 00:38:41 +0000240<div class="doc_text">
241
John Criswell0b5b5e92004-12-08 20:35:47 +0000242<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000243
244<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000245<li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
Reid Spencer00812e22005-05-17 02:47:27 +0000246 (and probably other unix-like systems).</li>
Chris Lattner000c73b2008-02-06 06:30:34 +0000247<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit and
Chris Lattner26299222006-11-18 07:51:14 +0000248 64-bit modes.</li>
Chris Lattner252b83d2008-02-06 18:00:06 +0000249<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000250<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
251 support is available for native builds with Visual C++).</li>
252<li>Sun UltraSPARC workstations running Solaris 8.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000253<li>Alpha-based machines running Debian GNU/Linux.</li>
254<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000255</ul>
256
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000257<p>The core LLVM infrastructure uses
258<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
259to the machine and operating system on which it is built. However, minor
260porting may be required to get LLVM to work on new platforms. We welcome your
261portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000262
Misha Brukman500bc302003-11-22 00:38:41 +0000263</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000264
265<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000266<div class="doc_section">
267 <a name="knownproblems">Known Problems</a>
268</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000269<!-- *********************************************************************** -->
270
Misha Brukman500bc302003-11-22 00:38:41 +0000271<div class="doc_text">
272
273<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000274component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000275sections. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000276href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000277there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000278
Misha Brukman500bc302003-11-22 00:38:41 +0000279</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000280
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000281<!-- ======================================================================= -->
282<div class="doc_subsection">
283 <a name="experimental">Experimental features included with this release</a>
284</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000285
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000286<div class="doc_text">
287
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000288<p>The following components of this LLVM release are either untested, known to
289be broken or unreliable, or are in early development. These components should
290not be relied on, and bugs should not be filed against them, but they may be
291useful to some people. In particular, if you would like to work on one of these
Chris Lattner49e693e2006-08-09 04:08:52 +0000292components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000293
294<ul>
Chris Lattner252b83d2008-02-06 18:00:06 +0000295<li>The <tt>-cee</tt> pass is known to be buggy and will be removed in
296 LLVM 2.3.</li>
Chris Lattner000c73b2008-02-06 06:30:34 +0000297<li>The MSIL, IA64, Alpha, and MIPS backends are experimental.</li>
298<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
299 value for this option.</li>
300<li>The llvmc tool is not supported.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000301</ul>
302
303</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000304
Misha Brukman500bc302003-11-22 00:38:41 +0000305<!-- ======================================================================= -->
306<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000307 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000308</div>
309
310<div class="doc_text">
311
312<ul>
Chris Lattner26299222006-11-18 07:51:14 +0000313<li>The X86 backend does not yet support <a href="http://llvm.org/PR879">inline
Chris Lattnercaf06342007-05-09 04:58:11 +0000314 assembly that uses the X86 floating point stack</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000315<li>The X86 backend occasionally has <a href="http://llvm.org/PR1649">alignment
316 problems</a> on operating systems that don't require 16-byte stack alignment
317 (including most non-darwin OS's like linux).</li>
Chris Lattner26299222006-11-18 07:51:14 +0000318</ul>
319
320</div>
321
322<!-- ======================================================================= -->
323<div class="doc_subsection">
324 <a name="ppc-be">Known problems with the PowerPC back-end</a>
325</div>
326
327<div class="doc_text">
328
329<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000330<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000331compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000332</ul>
333
334</div>
335
336<!-- ======================================================================= -->
337<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000338 <a name="arm-be">Known problems with the ARM back-end</a>
339</div>
340
341<div class="doc_text">
342
343<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000344<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000345processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000346results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000347<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
348</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000349<li>There is a bug in QEMU-ARM (<= 0.9.0) which causes it to incorrectly execute
350programs compiled with LLVM. Please use more recent versions of QEMU.</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000351</ul>
352
353</div>
354
355<!-- ======================================================================= -->
356<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000357 <a name="sparc-be">Known problems with the SPARC back-end</a>
358</div>
359
360<div class="doc_text">
361
362<ul>
363<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
364 support the 64-bit SPARC ABI (-m64).</li>
365</ul>
366
367</div>
368
369<!-- ======================================================================= -->
370<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000371 <a name="alpha-be">Known problems with the Alpha back-end</a>
372</div>
373
374<div class="doc_text">
375
376<ul>
377
378<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
379appropriate nops inserted to ensure restartability.</li>
380
John Criswellc0c186d2005-11-08 21:11:33 +0000381</ul>
382</div>
383
Chris Lattner26299222006-11-18 07:51:14 +0000384<!-- ======================================================================= -->
385<div class="doc_subsection">
386 <a name="ia64-be">Known problems with the IA64 back-end</a>
387</div>
388
389<div class="doc_text">
390
391<ul>
392
393<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
394made where the argument is not 16-byte aligned, as required on IA64. (Strictly
395speaking this is not a bug in the IA64 back-end; it will also be encountered
396when building C++ programs using the C back-end.)</li>
397
398<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
399ABI compliant layout of v-tables</a>. In particular, it just stores function
400pointers instead of function descriptors in the vtable. This bug prevents
401mixing C++ code compiled with LLVM with C++ objects compiled by other C++
402compilers.</li>
403
404<li>There are a few ABI violations which will lead to problems when mixing LLVM
405output with code built with other compilers, particularly for floating-point
406programs.</li>
407
408<li>Defining vararg functions is not supported (but calling them is ok).</li>
409
Chris Lattnercaf06342007-05-09 04:58:11 +0000410<li>The Itanium backend has bitrotted somewhat.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000411</ul>
412
413</div>
414
415<!-- ======================================================================= -->
416<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000417 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000418</div>
419
420<div class="doc_text">
421
422<ul>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000423<li><a href="http://llvm.org/PR802">The C backend does not support inline
424 assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000425<li><a href="http://llvm.org/PR1126">The C backend does not support vectors
426 yet</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000427<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
428 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
429 C++ code compiled with LLC or native compilers.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000430</ul>
431
432</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000433
Misha Brukman500bc302003-11-22 00:38:41 +0000434
435<!-- ======================================================================= -->
436<div class="doc_subsection">
437 <a name="c-fe">Known problems with the C front-end</a>
438</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000439
Chris Lattner79c3fe12003-10-02 04:57:28 +0000440<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000441<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000442
Misha Brukman500bc302003-11-22 00:38:41 +0000443<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000444
Chris Lattner252b83d2008-02-06 18:00:06 +0000445<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
446Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000447llvmdev mailing list if you are interested.</p>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000448
Misha Brukman500bc302003-11-22 00:38:41 +0000449</div>
450
451<!-- _______________________________________________________________________ -->
452<div class="doc_subsubsection">
453 Notes
454</div>
455
456<div class="doc_text">
Misha Brukman500bc302003-11-22 00:38:41 +0000457<ul>
458
Chris Lattnerd09c4ec2007-05-17 22:02:24 +0000459<li><p>llvm-gcc does <b>not</b> support <tt>__builtin_apply</tt> yet.
460 See <a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</p>
461</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000462
Duncan Sands32a83442007-05-18 09:04:20 +0000463<li><p>llvm-gcc <b>partially</b> supports these GCC extensions:</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000464 <ol>
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000465 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html#Nested%20Functions">Nested Functions</a>:
466
467 As in Algol and Pascal, lexical scoping of functions.
468 Nested functions are supported, but llvm-gcc does not support
Duncan Sands0869f4a2007-09-26 16:24:52 +0000469 taking the address of a nested function (except on the X86-32 target)
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000470 or non-local gotos.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000471
472 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Misha Brukman500bc302003-11-22 00:38:41 +0000473
John Criswelld000e1d2003-12-18 16:43:17 +0000474 Declaring that functions have no side effects or that they can never
Misha Brukman500bc302003-11-22 00:38:41 +0000475 return.<br>
476
Anton Korobeynikovbe6fe282007-11-16 11:12:01 +0000477 <b>Supported:</b> <tt>alias</tt>, <tt>always_inline</tt>, <tt>cdecl</tt>,
478 <tt>const</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
Anton Korobeynikov9413de32006-11-18 08:04:48 +0000479 <tt>deprecated</tt>, <tt>fastcall</tt>, <tt>format</tt>,
Anton Korobeynikovbe6fe282007-11-16 11:12:01 +0000480 <tt>format_arg</tt>, <tt>non_null</tt>, <tt>noinline</tt>,
481 <tt>noreturn</tt>, <tt>pure</tt>, <tt>regparm</tt>
Anton Korobeynikov8cea37b2007-01-23 12:35:46 +0000482 <tt>section</tt>, <tt>stdcall</tt>, <tt>unused</tt>, <tt>used</tt>,
483 <tt>visibility</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000484
Anton Korobeynikovbe6fe282007-11-16 11:12:01 +0000485 <b>Ignored:</b> <tt>nothrow</tt>, <tt>malloc</tt>,
486 <tt>no_instrument_function</tt></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000487 </ol>
Chris Lattnerd09c4ec2007-05-17 22:02:24 +0000488</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000489
Chris Lattnerd09c4ec2007-05-17 22:02:24 +0000490<li><p>llvm-gcc supports the vast majority of GCC extensions, including:</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000491
Chris Lattner79c3fe12003-10-02 04:57:28 +0000492 <ol>
Chris Lattnerd09c4ec2007-05-17 22:02:24 +0000493 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
494 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
495 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
496 Other built-in functions.</li>
497 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
498 Specifying attributes of variables.</li>
499 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.</li>
500 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
501 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
502 Arrays whose length is computed at run time.</li>
Chris Lattner7fe97dd2004-03-16 08:54:07 +0000503 <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 +0000504 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
505 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Typeof.html#Typeof">Typeof</a>: <code>typeof</code>: referring to the type of an expression.</li>
Tanya Lattnerca26c3e2004-06-22 03:48:17 +0000506 <li><a href="http://gcc.gnu.org/onlinedocs/gcc-3.4.0/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000507 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
508 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
509 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
510 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
511 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
512 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
513 <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>
514 <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 Lattner26299222006-11-18 07:51:14 +0000515 <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>
516 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
517 <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>
518 <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>
519 <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>
520 <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 Brukman500bc302003-11-22 00:38:41 +0000521 <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 +0000522 <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 +0000523 <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 +0000524 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
525or arrays as values.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000526 <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 +0000527 <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 +0000528 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
529 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
530 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
Tanya Lattner78537e42004-12-08 18:29:38 +0000531 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Comments.html#C_002b_002b-Comments">C++ Comments</a>: C++ comments are recognized.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000532 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
533 <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>
534 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
535 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
536 <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>
537 <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>
538 <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 +0000539 <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 +0000540 <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>
541 <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 +0000542 </ol></li>
543
544</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000545
Misha Brukman500bc302003-11-22 00:38:41 +0000546<p>If you run into GCC extensions which have not been included in any of these
547lists, please let us know (also including whether or not they work).</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000548
Misha Brukman500bc302003-11-22 00:38:41 +0000549</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000550
Misha Brukman500bc302003-11-22 00:38:41 +0000551<!-- ======================================================================= -->
552<div class="doc_subsection">
553 <a name="c++-fe">Known problems with the C++ front-end</a>
554</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000555
Misha Brukman500bc302003-11-22 00:38:41 +0000556<div class="doc_text">
557
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000558<p>The C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000559tested and works for a number of non-trivial programs, including LLVM
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000560itself, Qt, Mozilla, etc.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000561
Misha Brukman500bc302003-11-22 00:38:41 +0000562<ul>
Chris Lattner000c73b2008-02-06 06:30:34 +0000563<li>Exception handling only works well on the X86 and PowerPC targets.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000564</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000565
Misha Brukman500bc302003-11-22 00:38:41 +0000566</div>
567
Misha Brukman500bc302003-11-22 00:38:41 +0000568
Chris Lattner98a493c2005-05-15 16:01:20 +0000569
Chris Lattner79c3fe12003-10-02 04:57:28 +0000570<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000571<div class="doc_section">
572 <a name="additionalinfo">Additional Information</a>
573</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000574<!-- *********************************************************************** -->
575
Misha Brukman500bc302003-11-22 00:38:41 +0000576<div class="doc_text">
577
Chris Lattner416db102005-05-16 17:13:10 +0000578<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000579href="http://llvm.org">LLVM web page</a>, in particular in the <a
580href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000581contains versions of the API documentation which is up-to-date with the
582Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000583You can access versions of these documents specific to this release by going
584into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000585
Misha Brukman500bc302003-11-22 00:38:41 +0000586<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerc463b272005-10-29 07:07:09 +0000587us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000588lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000589
Misha Brukman500bc302003-11-22 00:38:41 +0000590</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000591
592<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000593
Misha Brukman500bc302003-11-22 00:38:41 +0000594<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000595<address>
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600
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000601 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
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Misha Brukman2061e892003-11-22 01:23:39 +0000603</address>
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