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Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]7 <title>LLVM 2.4 Release Notes</title>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]8</head>
9<body>
10
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]11<div class="doc_title">LLVM 2.4 Release Notes</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]12
13<ol>
14 <li><a href="#intro">Introduction</a></li>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]15 <li><a href="#changes">Major Changes and Sub-project Status</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]16 <li><a href="#whatsnew">What's New?</a></li>
17 <li><a href="GettingStarted.html">Installation Instructions</a></li>
18 <li><a href="#portability">Portability and Supported Platforms</a></li>
19 <li><a href="#knownproblems">Known Problems</a>
20 <li><a href="#additionalinfo">Additional Information</a></li>
21</ol>
22
23<div class="doc_author">
24 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
25</div>
26
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]27<!-- Done through Week-of-Mon-20080324.txt -->
28
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]29<!-- *********************************************************************** -->
30<div class="doc_section">
31 <a name="intro">Introduction</a>
32</div>
33<!-- *********************************************************************** -->
34
35<div class="doc_text">
36
37<p>This document contains the release notes for the LLVM compiler
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]38infrastructure, release 2.4. Here we describe the status of LLVM, including
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]39major improvements from the previous release and any known problems. All LLVM
40releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
41releases web site</a>.</p>
42
43<p>For more information about LLVM, including information about the latest
44release, please check out the <a href="http://llvm.org/">main LLVM
45web site</a>. If you have questions or comments, the <a
46href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
47list</a> is a good place to send them.</p>
48
49<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]50main 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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]53
54</div>
55
56<!-- *********************************************************************** -->
57<div class="doc_section">
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]58 <a name="changes">Major Changes and Sub-project Status</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]59</div>
60<!-- *********************************************************************** -->
61
62<div class="doc_text">
63
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]64<p>This is the fifteenth public release of the LLVM Compiler Infrastructure.
65It includes a large number of features and refinements from LLVM 2.3.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]66
67</div>
68
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]69<!-- Unfinished features in 2.4:
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]70 Machine LICM
71 Machine Sinking
72 LegalizeDAGTypes
73 -->
74
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]75<!--=========================================================================-->
76<div class="doc_subsection">
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]77<a name="changes">Major Changes in LLVM 2.4</a>
Chris Lattner41bf8e92008-02-10 07:04:35 +0000[diff] [blame]78</div>
79
80<div class="doc_text">
81
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]82<p>....</p>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]83
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]84<p>LLVM API Changes:</p>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]85
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]86<ul>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]87<li>....</li>
Daniel Dunbardcb129a2008-10-11 21:26:56 +0000[diff] [blame]88
89<li>... Attributes changes ... </li>
90
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame^]91<li>The <tt>DbgStopPointInst</tt> methods <tt>getDirectory</tt> and
92<tt>getFileName</tt> now return <tt>Value*</tt> instead of strings. These can be
93converted to strings using <tt>llvm::GetConstantStringInfo</tt> defined via
94"llvm/Analysis/ValueTracking.h".</li>
Daniel Dunbardcb129a2008-10-11 21:26:56 +0000[diff] [blame]95
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame^]96<li>API change: BinaryOperator::create -> Create (CmpInst, CastInst too)</li>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]97</ul>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]98</div>
99
100<!--=========================================================================-->
101<div class="doc_subsection">
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]102<a name="otherprojects">Other LLVM Sub-Projects</a>
103</div>
104
105<div class="doc_text">
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]106<p>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]107The core LLVM 2.4 distribution currently consists of code from the core LLVM
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]108repository (which roughly contains the LLVM optimizer, code generators and
109supporting tools) and the llvm-gcc repository. In addition to this code, the
110LLVM Project includes other sub-projects that are in development. The two which
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]111are the most actively developed are the <a href="#clang">Clang Project</a> and
112<a href="#vmkit">vmkit Project</a>.
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]113</p>
114</div>
115
116<!--=========================================================================-->
117<div class="doc_subsubsection">
118<a name="vmkit">vmkit</a>
119</div>
120
121<div class="doc_text">
122<p>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]123The <a href="http://vmkit.llvm.org/">"vmkit" project</a> is an implementation of
124a JVM and a CLI Virtual Machines (Microsoft .NET is an
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]125implementation of the CLI) using the Just-In-Time compiler of LLVM.</p>
126
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]127<p>...</p>
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]128
129</div>
130
131<!--=========================================================================-->
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]132<div class="doc_subsubsection">
133<a name="clang">Clang</a>
134</div>
135
136<div class="doc_text">
137
138<p>The <a href="http://clang.llvm.org/">Clang project</a> is an effort to build
139a set of new 'LLVM native' front-end technologies for the LLVM optimizer
140and code generator. Clang is continuing to make major strides forward in all
141areas. Its C and Objective-C parsing support is very solid, and the code
142generation support is far enough along to build many C applications. While not
143yet production quality, it is progressing very nicely. In addition, C++
144front-end work has started to make significant progress.</p>
145
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]146<p>Codegen progress/state
147</p>
148
149<p>
150<a href="http://clang.llvm.org/StaticAnalysis.html">static analysis tool</a>
151</p>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]152
153</div>
154
155
156<!-- *********************************************************************** -->
157<div class="doc_section">
158 <a name="whatsnew">What's New?</a>
159</div>
160<!-- *********************************************************************** -->
161
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]162<div class="doc_text">
163
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]164<p>LLVM 2.4 includes a huge number of bug fixes, performance tweaks and minor
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]165improvements. Some of the major improvements and new features are listed in
166this section.
167</p>
168</div>
169
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]170<!--=========================================================================-->
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]171<div class="doc_subsection">
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]172<a name="majorfeatures">Major New Features</a>
173</div>
174
175<div class="doc_text">
176
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]177<p>LLVM 2.4 includes several major new capabilities:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]178
179<ul>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]180<li>
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame^]181 <p>MRVs got generalized to FCAs. getresult is gone, ret with multiple values
182 is gone.</p>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]183 </li>
184
185<li><p>fast isel, -O0 compile times</p></li>
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]186
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]187<li><p>Attrs changes?</p></li>
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]188
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame^]189
190<li><p>Initial PIC16 port</p></li>
191
192<li><p> builtin sync_compare_and_swap builtins + intrinsics</p></li>
193
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]194<li><p>...</p></li>
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]195
Chris Lattner5ba16862008-02-10 08:18:42 +0000[diff] [blame]196</ul>
197
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]198</div>
199
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]200
201<!--=========================================================================-->
202<div class="doc_subsection">
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]203<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]204</div>
205
206<div class="doc_text">
207
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]208<p>LLVM 2.4 fully supports the llvm-gcc 4.2 front-end, and includes support
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]209for the C, C++, Objective-C, Ada, and Fortran front-ends.</p>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]210
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]211<p>
212<ul>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]213<li>...</li>
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]214
Gabor Greif0e49cc82008-06-09 06:06:18 +0000[diff] [blame]215</ul>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]216
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]217</div>
218
219
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]220<!--=========================================================================-->
221<div class="doc_subsection">
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]222<a name="coreimprovements">LLVM Core Improvements</a>
223</div>
224
225<div class="doc_text">
226<p>New features include:
227</p>
228
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]229<ul>
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame^]230<li>use diet patch landed: saved 15% IR memory footprint</li>
231<li>LLVM IR now directly represents "common" linkage, instead of
232 representing it as a form of weak linkage.</li>
233
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]234<li>...</li>
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]235</ul>
236
237</div>
238
239<!--=========================================================================-->
240<div class="doc_subsection">
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]241<a name="optimizer">Optimizer Improvements</a>
242</div>
243
244<div class="doc_text">
245
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]246<p>In addition to a huge array of bug fixes and minor performance tweaks, the
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]247LLVM 2.4 optimizers support a few major enhancements:</p>
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]248
249<ul>
250
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame^]251<li>Old-ADCE used control dependence and deleted output-free infinite loops.
252Added a new Loop deletion pass (for deleting output free provably-finite loops)
253and rewrote ADCE to be simpler faster, and not need control dependence.</li>
254
255<li>SparsePropagation framework for lattice-based dataflow solvers.</li>
256
257<li>LoadVN and GCSE finally bit the dust?</li>
258
259<li>Tail duplication was is removed from the standard optimizer sequence.</li>
260
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]261</ul>
262
263</div>
264
265<!--=========================================================================-->
266<div class="doc_subsection">
267<a name="codegen">Code Generator Improvements</a>
268</div>
269
270<div class="doc_text">
271
272<p>We put a significant amount of work into the code generator infrastructure,
273which allows us to implement more aggressive algorithms and make it run
274faster:</p>
275
276<ul>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]277<li>Selection dag speedups</li>
278<li>...</li>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]279
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]280</ul>
281
282</div>
283
284
285<!--=========================================================================-->
286<div class="doc_subsection">
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]287<a name="x86specific">X86/X86-64 Specific Improvements</a>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]288</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]289
290<div class="doc_text">
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]291<p>New target-specific features include:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]292</p>
293
294<ul>
Anton Korobeynikovd9a17932008-10-11 18:27:16 +0000[diff] [blame]295<li>Exception handling is supported by default on x86-64 linux platform.</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]296<li>...</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]298</ul>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]299
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]300</div>
301
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]302<!--=========================================================================-->
303<div class="doc_subsection">
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]304<a name="targetspecific">Other Target Specific Improvements</a>
305</div>
306
307<div class="doc_text">
308<p>New target-specific features include:
309</p>
310
311<ul>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]312<li>....</li>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]313</ul>
314
315</div>
316
317
318
319<!--=========================================================================-->
320<div class="doc_subsection">
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]321<a name="otherimprovements">Other Improvements</a>
322</div>
323
324<div class="doc_text">
325<p>New features include:
326</p>
327
328<ul>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]329<li>...</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]330</ul>
331
332</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]333
334<!-- *********************************************************************** -->
335<div class="doc_section">
336 <a name="portability">Portability and Supported Platforms</a>
337</div>
338<!-- *********************************************************************** -->
339
340<div class="doc_text">
341
342<p>LLVM is known to work on the following platforms:</p>
343
344<ul>
Gabor Greif5e75e652008-06-05 18:39:01 +0000[diff] [blame]345<li>Intel and AMD machines (IA32) running Red Hat Linux, Fedora Core and FreeBSD
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]346 (and probably other unix-like systems).</li>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]347<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]348 64-bit modes.</li>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]349<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]350<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
351 support is available for native builds with Visual C++).</li>
Gabor Greif5e75e652008-06-05 18:39:01 +0000[diff] [blame]352<li>Sun UltraSPARC workstations running Solaris 10.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]353<li>Alpha-based machines running Debian GNU/Linux.</li>
Gabor Greif5e75e652008-06-05 18:39:01 +0000[diff] [blame]354<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]355</ul>
356
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]357<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]358to the machine and operating system on which it is built. However, minor
359porting may be required to get LLVM to work on new platforms. We welcome your
360portability patches and reports of successful builds or error messages.</p>
361
362</div>
363
364<!-- *********************************************************************** -->
365<div class="doc_section">
366 <a name="knownproblems">Known Problems</a>
367</div>
368<!-- *********************************************************************** -->
369
370<div class="doc_text">
371
372<p>This section contains all known problems with the LLVM system, listed by
373component. As new problems are discovered, they will be added to these
374sections. If you run into a problem, please check the <a
375href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
376there isn't already one.</p>
377
378</div>
379
380<!-- ======================================================================= -->
381<div class="doc_subsection">
382 <a name="experimental">Experimental features included with this release</a>
383</div>
384
385<div class="doc_text">
386
387<p>The following components of this LLVM release are either untested, known to
388be broken or unreliable, or are in early development. These components should
389not be relied on, and bugs should not be filed against them, but they may be
390useful to some people. In particular, if you would like to work on one of these
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]391components, please contact us on the <a
392href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]393
394<ul>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]395<li>The MSIL, IA64, Alpha, SPU, and MIPS backends are experimental.</li>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]396<li>The llc "<tt>-filetype=asm</tt>" (the default) is the only supported
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]397 value for this option.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]398</ul>
399
400</div>
401
402<!-- ======================================================================= -->
403<div class="doc_subsection">
404 <a name="x86-be">Known problems with the X86 back-end</a>
405</div>
406
407<div class="doc_text">
408
409<ul>
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000[diff] [blame]410 <li>The X86 backend does not yet support
411 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
412 floating point stack</a>. It supports the 'f' and 't' constraints, but not
413 'u'.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]414 <li>The X86 backend generates inefficient floating point code when configured
415 to generate code for systems that don't have SSE2.</li>
Duncan Sands8b4f3772008-06-08 19:38:43 +0000[diff] [blame]416 <li>Win64 code generation wasn't widely tested. Everything should work, but we
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000[diff] [blame]417 expect small issues to happen. Also, llvm-gcc cannot build mingw64 runtime
418 currently due
419 to <a href="http://llvm.org/PR2255">several</a>
Chris Lattnerf06141a2008-06-08 23:12:47 +0000[diff] [blame]420 <a href="http://llvm.org/PR2257">bugs</a> due to lack of support for the
421 'u' inline assembly constraint and X87 floating point inline assembly.</li>
Dan Gohman3882ecb2008-06-08 23:05:11 +0000[diff] [blame]422 <li>The X86-64 backend does not yet support the LLVM IR instruction
423 <tt>va_arg</tt>. Currently, the llvm-gcc front-end supports variadic
424 argument constructs on X86-64 by lowering them manually.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]425</ul>
426
427</div>
428
429<!-- ======================================================================= -->
430<div class="doc_subsection">
431 <a name="ppc-be">Known problems with the PowerPC back-end</a>
432</div>
433
434<div class="doc_text">
435
436<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]437<li>The Linux PPC32/ABI support needs testing for the interpreter and static
438compilation, and lacks support for debug information.</li>
439</ul>
440
441</div>
442
443<!-- ======================================================================= -->
444<div class="doc_subsection">
445 <a name="arm-be">Known problems with the ARM back-end</a>
446</div>
447
448<div class="doc_text">
449
450<ul>
451<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]452processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]453results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
454<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
455</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]456<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly
457 execute
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]458programs compiled with LLVM. Please use more recent versions of QEMU.</li>
459</ul>
460
461</div>
462
463<!-- ======================================================================= -->
464<div class="doc_subsection">
465 <a name="sparc-be">Known problems with the SPARC back-end</a>
466</div>
467
468<div class="doc_text">
469
470<ul>
471<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
472 support the 64-bit SPARC ABI (-m64).</li>
473</ul>
474
475</div>
476
477<!-- ======================================================================= -->
478<div class="doc_subsection">
479 <a name="alpha-be">Known problems with the Alpha back-end</a>
480</div>
481
482<div class="doc_text">
483
484<ul>
485
486<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
487appropriate nops inserted to ensure restartability.</li>
488
489</ul>
490</div>
491
492<!-- ======================================================================= -->
493<div class="doc_subsection">
494 <a name="ia64-be">Known problems with the IA64 back-end</a>
495</div>
496
497<div class="doc_text">
498
499<ul>
Chris Lattnerf06141a2008-06-08 23:12:47 +0000[diff] [blame]500<li>The Itanium backend is highly experimental, and has a number of known
501 issues. We are looking for a maintainer for the Itanium backend. If you
502 are interested, please contact the llvmdev mailing list.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]503</ul>
504
505</div>
506
507<!-- ======================================================================= -->
508<div class="doc_subsection">
509 <a name="c-be">Known problems with the C back-end</a>
510</div>
511
512<div class="doc_text">
513
514<ul>
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]515<li><a href="http://llvm.org/PR802">The C backend has only basic support for
516 inline assembly code</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]517<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
518 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]519 C++ code compiled with llc or native compilers.</li>
Duncan Sandsbd0ad6e2008-02-10 13:40:55 +0000[diff] [blame]520<li>The C backend does not support all exception handling constructs.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]521</ul>
522
523</div>
524
525
526<!-- ======================================================================= -->
527<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]528 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]529</div>
530
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]531<div class="doc_text">
532
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]533<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
534Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]535llvmdev mailing list if you are interested.</p>
536
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]537<p>The only major language feature of GCC not supported by llvm-gcc is
538 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
539 are only supported on some targets. For example, trampolines are only
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]540 supported on some targets (these are used when you take the address of a
541 nested function).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]542
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]543<p>If you run into GCC extensions which are not supported, please let us know.
544</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]545
546</div>
547
548<!-- ======================================================================= -->
549<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]550 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]551</div>
552
553<div class="doc_text">
554
555<p>The C++ front-end is considered to be fully
556tested and works for a number of non-trivial programs, including LLVM
557itself, Qt, Mozilla, etc.</p>
558
559<ul>
Anton Korobeynikovd9a17932008-10-11 18:27:16 +0000[diff] [blame]560<li>Exception handling works well on the X86 and PowerPC targets. Currently
561 only linux and darwin targets are supported (both 32 and 64 bit).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]562</ul>
563
564</div>
565
566
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]567<!-- ======================================================================= -->
568<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]569 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]570</div>
571
572<div class="doc_text">
573The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
574technology and problems should be expected.
575<ul>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]576<li>The Ada front-end currently only builds on X86-32. This is mainly due
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]577to lack of trampoline support (pointers to nested functions) on other platforms,
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]578however it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]579which does support trampolines.</li>
580<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
581Workaround: configure with --disable-bootstrap.</li>
582<li>The c380004 and <a href="http://llvm.org/PR2010">c393010</a> ACATS tests
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]583fail (c380004 also fails with gcc-4.2 mainline). When built at -O3, the
584<a href="http://llvm.org/PR2421">cxg2021</a> ACATS test also fails.</li>
585<li>Some gcc specific Ada tests continue to crash the compiler. The testsuite
586reports most tests as having failed even though they pass.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]587<li>The -E binder option (exception backtraces)
588<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
589crashing if an exception is raised. Workaround: do not use -E.</li>
590<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
591or finish at a non-byte offset</a> in a record. Workaround: do not pack records
592or use representation clauses that result in a field of a non-discrete type
593starting or finishing in the middle of a byte.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]594<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
595'main' as generated by the Ada binder to be invalid</a>.
596Workaround: hand edit the file to use pointers for <tt>argv</tt> and
597<tt>envp</tt> rather than integers.</li>
598<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
599ignored</a>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]600</ul>
601</div>
602
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]603<!-- *********************************************************************** -->
604<div class="doc_section">
605 <a name="additionalinfo">Additional Information</a>
606</div>
607<!-- *********************************************************************** -->
608
609<div class="doc_text">
610
611<p>A wide variety of additional information is available on the <a
612href="http://llvm.org">LLVM web page</a>, in particular in the <a
613href="http://llvm.org/docs/">documentation</a> section. The web page also
614contains versions of the API documentation which is up-to-date with the
615Subversion version of the source code.
616You can access versions of these documents specific to this release by going
617into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
618
619<p>If you have any questions or comments about LLVM, please feel free to contact
620us via the <a href="http://llvm.org/docs/#maillist"> mailing
621lists</a>.</p>
622
623</div>
624
625<!-- *********************************************************************** -->
626
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