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gerrit-public.fairphone.software / toolchain / llvm-project / a1a4c9a227b5a2ffe5337f99e483288fc228da5d / . / llvm / docs / ReleaseNotes.html
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Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]7 <title>LLVM 2.3 Release Notes</title>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]8</head>
9<body>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]10
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]11<div class="doc_title">LLVM 2.3 Release Notes</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]12
13<ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]14 <li><a href="#intro">Introduction</a></li>
15 <li><a href="#whatsnew">What's New?</a></li>
Chris Lattner77a51732004-04-30 22:17:12 +0000[diff] [blame]16 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]18 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]19 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]20</ol>
21
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]22<div class="doc_author">
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]23 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]24</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]25
26<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]27<div class="doc_section">
28 <a name="intro">Introduction</a>
29</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]30<!-- *********************************************************************** -->
31
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]32<div class="doc_text">
33
34<p>This document contains the release notes for the LLVM compiler
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]35infrastructure, release 2.3. Here we describe the status of LLVM, including
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]36major improvements from the previous release and any known problems. All LLVM
Chris Lattner98a33492007-05-09 04:58:11 +0000[diff] [blame]37releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]38releases web site</a>.</p>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]39
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]40<p>For more information about LLVM, including information about the latest
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]41release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattnere7525b52003-10-07 21:38:31 +0000[diff] [blame]42web 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 +0000[diff] [blame]44list</a> is a good place to send them.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]45
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]46<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]47main LLVM web page, this document applies to the <i>next</i> release, not the
48current one. To see the release notes for a specific releases, please see the
49<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]50
51</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]52
53<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]54<div class="doc_section">
55 <a name="whatsnew">What's New?</a>
56</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]57<!-- *********************************************************************** -->
58
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]59<div class="doc_text">
60
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]61<p>This is the fourteenth public release of the LLVM Compiler Infrastructure.
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]62It includes a large number of features and refinements from LLVM 2.2.</p>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]63
Chris Lattner21a90402004-05-24 04:50:25 +0000[diff] [blame]64</div>
65
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]66<!-- Unfinished features in 2.3:
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]67 Index Set Splitting not enabled by default
68 Machine LICM
69 Machine Sinking
70 LegalizeDAGTypes
71 -->
72
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]73<!--=========================================================================-->
Chris Lattner406bddf2005-05-15 05:44:51 +0000[diff] [blame]74<div class="doc_subsection">
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]75<a name="deprecation">Removed features in LLVM 2.3</a>
Chris Lattnera2735862008-02-10 07:04:35 +0000[diff] [blame]76</div>
77
78<div class="doc_text">
79
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]80<p>LLVM 2.2 was the last LLVM release to support llvm-gcc 4.0 and llvm-upgrade.
81llvm-gcc 4.0 has been replaced with llvm-gcc 4.2. llvm-upgrade was useful for
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]82upgrading LLVM 1.9 files to LLVM 2.x syntax, but you can always use a previous
83LLVM release to do this. One nice impact of this is that the LLVM regressionn
84test suite no longer depends on llvm-upgrade, which makes it run faster.</p>
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]85
86</div>
87
88<!--=========================================================================-->
89<div class="doc_subsection">
90<a name="majorfeatures">Major New Features</a>
91</div>
92
93<div class="doc_text">
94
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]95<p>LLVM 2.3 includes several major new capabilities:</p>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]96
97<ul>
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]98<li>Multiple Return Value Support</li>
Chris Lattner458e79f2008-02-10 08:18:42 +0000[diff] [blame]99</ul>
100
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]101</div>
102
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]103
104<!--=========================================================================-->
105<div class="doc_subsection">
106<a name="frontends">llvm-gcc 4.2 Improvements and Clang</a>
107</div>
108
109<div class="doc_text">
110
111<p>LLVM 2.3 fully supports llvm-gcc 4.2 front-end.</p>
112
113<p>llvm-gcc 4.2 includes numerous fixes to better support the Objective-C
114front-end. Objective-C now works very well on Mac OS/X.</p>
115
116<p>llvm-gcc 4.2 includes many other fixes which improve conformance with the
117relevant parts of the GCC testsuite.</p>
118
119<p>The <a href="http://clang.llvm.org/">clang project</a> is an effort to build
120a set of new 'llvm native' front-end technologies for the LLVM optimizer
121and code generator. Currently, its C and Objective-C support is maturing
122nicely, and it has advanced source-to-source analysis and transformation
123capabilities. If you are interested in building source-level tools for C and
124Objective-C (and eventually C++), you should take a look. However, note that
125clang is not an official part of the LLVM 2.3 release. If you are interested in
126this project, please see its <a href="http://clang.llvm.org/">web site</a>.</p>
127
128</div>
129
130
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]131<!--=========================================================================-->
132<div class="doc_subsection">
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]133<a name="coreimprovements">LLVM Core Improvements</a>
134</div>
135
136<div class="doc_text">
137<p>New features include:
138</p>
139
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]140
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]141Common linkage?
142
143Atomic operation support, Alpha, X86, PowerPC. "__sync_syncronize"
144
145<ul>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]146</ul>
147
148</div>
149
150<!--=========================================================================-->
151<div class="doc_subsection">
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]152<a name="codegen">Code Generator Improvements</a>
153</div>
154
155<div class="doc_text">
156
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]157<p>We put a significant amount of work into the code generator infrastructure,
158which allows us to implement more aggressive algorithms and make it run
159faster:</p>
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]160
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]161<ul>
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]162<li>MemOperand in the code generator: describe me!.</li>
163<li>i128 support and APInt through most of codegen.</li>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]164</ul>
165
166</div>
167
168<!--=========================================================================-->
169<div class="doc_subsection">
170<a name="optimizer">Optimizer Improvements</a>
171</div>
172
173<div class="doc_text">
174
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]175<p>In addition to a huge array of bug fixes and minor performance tweaks, the
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]176LLVM 2.3 optimizers support a few major enhancements:</p>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]177
178<ul>
179
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]180<li>Loop index set splitting on by default: describe me.</li>
181<li>LLVM includes a new memcpy optimization pass which optimizes out dead
182memcpy calls and unneeded copies of aggregates.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]183</ul>
184
185</div>
186
187
188<!--=========================================================================-->
189<div class="doc_subsection">
190<a name="targetspecific">Target Specific Improvements</a>
191</div>
Chris Lattner727c3742007-05-18 06:33:02 +0000[diff] [blame]192
Chris Lattner89e761c2006-04-18 06:32:08 +0000[diff] [blame]193<div class="doc_text">
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]194<p>New target-specific features include:
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]195</p>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]196
197<ul>
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]198<li>llvm-gcc's X86-64 ABI conformance is far improved, particularly in the
199 area of passing and returning structures by value. llvm-gcc Compiled code
200 now interoperates very well on X86-64 systems with other compilers.</li>
201
202<li>The LLVM X86 backend now supports the support SSE 4.1 instruction set, and
203 the llvm-gcc 4.2 front-end supports the SSE 4.1 compiler builtins.</li>
204
205<li>The X86 backend now does a number of optimizations that aim to avoid
206 converting numbers back and forth from SSE registers to the X87 floating
207 point stack.</li>
208
209<li>The X86 backend now supports the "sseregparm" options in GCC, which allow
210 functions to be tagged as passing floating point values in SSE
211 registers.</li>
212
213<li>Trampolines (taking the address of a nested function) now work on
214 Linux/x86-64.</li>
215
216
Chris Lattner8ce1ba42007-05-17 21:41:31 +0000[diff] [blame]217</ul>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]218
Chris Lattner8ce1ba42007-05-17 21:41:31 +0000[diff] [blame]219</div>
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]220
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]221<!--=========================================================================-->
222<div class="doc_subsection">
223<a name="otherimprovements">Other Improvements</a>
224</div>
225
226<div class="doc_text">
227<p>New features include:
228</p>
229
230<ul>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]231</ul>
232
233</div>
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]234
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]235<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]236<div class="doc_section">
237 <a name="portability">Portability and Supported Platforms</a>
238</div>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]239<!-- *********************************************************************** -->
240
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]241<div class="doc_text">
242
John Criswell64307722004-12-08 20:35:47 +0000[diff] [blame]243<p>LLVM is known to work on the following platforms:</p>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]244
245<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]246<li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
Reid Spencer9803b402005-05-17 02:47:27 +0000[diff] [blame]247 (and probably other unix-like systems).</li>
Chris Lattner7422bce2008-02-06 06:30:34 +0000[diff] [blame]248<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit and
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]249 64-bit modes.</li>
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]250<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]251<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
252 support is available for native builds with Visual C++).</li>
253<li>Sun UltraSPARC workstations running Solaris 8.</li>
John Criswelld5234922005-05-13 20:28:15 +0000[diff] [blame]254<li>Alpha-based machines running Debian GNU/Linux.</li>
255<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]256</ul>
257
Brian Gaekee3e557e2004-05-09 05:28:35 +0000[diff] [blame]258<p>The core LLVM infrastructure uses
259<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
260to the machine and operating system on which it is built. However, minor
261porting may be required to get LLVM to work on new platforms. We welcome your
262portability patches and reports of successful builds or error messages.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]263
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]264</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]265
266<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]267<div class="doc_section">
268 <a name="knownproblems">Known Problems</a>
269</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]270<!-- *********************************************************************** -->
271
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]272<div class="doc_text">
273
274<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]275component. As new problems are discovered, they will be added to these
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]276sections. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]277href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]278there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]279
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]280</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]281
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]282<!-- ======================================================================= -->
283<div class="doc_subsection">
284 <a name="experimental">Experimental features included with this release</a>
285</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]286
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]287<div class="doc_text">
288
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]289<p>The following components of this LLVM release are either untested, known to
290be broken or unreliable, or are in early development. These components should
291not be relied on, and bugs should not be filed against them, but they may be
292useful to some people. In particular, if you would like to work on one of these
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]293components, please contact us on the <a
294href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]295
296<ul>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]297<li>The MSIL, IA64, Alpha, SPU, and MIPS backends are experimental.</li>
Chris Lattner7422bce2008-02-06 06:30:34 +0000[diff] [blame]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 Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]301</ul>
302
303</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]304
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]305<!-- ======================================================================= -->
306<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]307 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]308</div>
309
310<div class="doc_text">
311
312<ul>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]313<li>The X86 backend does not yet support <a href="http://llvm.org/PR879">inline
Chris Lattner98a33492007-05-09 04:58:11 +0000[diff] [blame]314 assembly that uses the X86 floating point stack</a>.</li>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]315<li>The X86 backend generates inefficient floating point code when configured to
316 generate code for systems that don't have SSE2.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]317</ul>
318
319</div>
320
321<!-- ======================================================================= -->
322<div class="doc_subsection">
323 <a name="ppc-be">Known problems with the PowerPC back-end</a>
324</div>
325
326<div class="doc_text">
327
328<ul>
Nicolas Geoffray77d99502007-05-15 09:21:28 +0000[diff] [blame]329<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]330compilation, and lacks support for debug information.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]331</ul>
332
333</div>
334
335<!-- ======================================================================= -->
336<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]337 <a name="arm-be">Known problems with the ARM back-end</a>
338</div>
339
340<div class="doc_text">
341
342<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]343<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands47fc0a22007-09-26 15:59:54 +0000[diff] [blame]344processors, thumb programs can crash or produce wrong
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]345results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]346<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
347</li>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]348<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly execute
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]349programs compiled with LLVM. Please use more recent versions of QEMU.</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]350</ul>
351
352</div>
353
354<!-- ======================================================================= -->
355<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]356 <a name="sparc-be">Known problems with the SPARC back-end</a>
357</div>
358
359<div class="doc_text">
360
361<ul>
362<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
363 support the 64-bit SPARC ABI (-m64).</li>
364</ul>
365
366</div>
367
368<!-- ======================================================================= -->
369<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]370 <a name="alpha-be">Known problems with the Alpha back-end</a>
371</div>
372
373<div class="doc_text">
374
375<ul>
376
377<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
378appropriate nops inserted to ensure restartability.</li>
379
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]380</ul>
381</div>
382
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]383<!-- ======================================================================= -->
384<div class="doc_subsection">
385 <a name="ia64-be">Known problems with the IA64 back-end</a>
386</div>
387
388<div class="doc_text">
389
390<ul>
391
392<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
393made where the argument is not 16-byte aligned, as required on IA64. (Strictly
394speaking this is not a bug in the IA64 back-end; it will also be encountered
395when building C++ programs using the C back-end.)</li>
396
397<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
398ABI compliant layout of v-tables</a>. In particular, it just stores function
399pointers instead of function descriptors in the vtable. This bug prevents
400mixing C++ code compiled with LLVM with C++ objects compiled by other C++
401compilers.</li>
402
403<li>There are a few ABI violations which will lead to problems when mixing LLVM
404output with code built with other compilers, particularly for floating-point
405programs.</li>
406
407<li>Defining vararg functions is not supported (but calling them is ok).</li>
408
Chris Lattner98a33492007-05-09 04:58:11 +0000[diff] [blame]409<li>The Itanium backend has bitrotted somewhat.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]410</ul>
411
412</div>
413
414<!-- ======================================================================= -->
415<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]416 <a name="c-be">Known problems with the C back-end</a>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]417</div>
418
419<div class="doc_text">
420
421<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame^]422<li><a href="http://llvm.org/PR802">The C backend has only basic support for
423 inline assembly code</a>.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000[diff] [blame]424<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
425 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
426 C++ code compiled with LLC or native compilers.</li>
Duncan Sandse09506a2008-02-10 13:40:55 +0000[diff] [blame]427<li>The C backend does not support all exception handling constructs.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]428</ul>
429
430</div>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]431
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]432
433<!-- ======================================================================= -->
434<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame^]435 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]436</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000[diff] [blame]437
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]438<!-- _______________________________________________________________________ -->
Chris Lattner5a8a7282003-12-14 05:03:43 +0000[diff] [blame]439<div class="doc_subsubsection">Bugs</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]440
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]441<div class="doc_text">
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]442
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]443<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
444Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]445llvmdev mailing list if you are interested.</p>
Chris Lattner44124232006-08-08 17:27:28 +0000[diff] [blame]446
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame^]447<p>The only major language feature of GCC not supported by llvm-gcc is
448 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
449 are only supported on some targets. For example, trampolines are only
450 supported on some targets, which are used when you take the address of a
451 nested function.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]452
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame^]453<p>If you run into GCC extensions which are not supported, please let us know.
454</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]455
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]456</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]457
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]458<!-- ======================================================================= -->
459<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame^]460 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]461</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]462
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]463<div class="doc_text">
464
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]465<p>The C++ front-end is considered to be fully
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]466tested and works for a number of non-trivial programs, including LLVM
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]467itself, Qt, Mozilla, etc.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]468
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]469<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame^]470<li>Exception handling works well on the X86 and PowerPC targets, including
471x86-64 darwin. This works when linking to a libstdc++ compiled by GCC. It is
472supported on x86-64 linux, but that is disabled by default in this release.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]473</ul>
Chris Lattner46ecf612003-10-07 22:14:37 +0000[diff] [blame]474
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]475</div>
476
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]477
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]478<!-- ======================================================================= -->
479<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame^]480 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]481</div>
482
483<div class="doc_text">
484The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
485technology and problems should be expected.
486<ul>
487<li>The Ada front-end currently only builds on x86-32. This is mainly due
488to lack of trampoline support (pointers to nested functions) on other platforms,
489however it <a href="http://llvm.org/PR2006">also fails to build on x86-64</a>
490which does support trampolines.</li>
491<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
492Workaround: configure with --disable-bootstrap.</li>
493<li>The c380004 and <a href="http://llvm.org/PR2010">c393010</a> ACATS tests
494fail (c380004 also fails with gcc-4.2 mainline).</li>
495<li>Many gcc specific Ada tests continue to crash the compiler.</li>
496<li>The -E binder option (exception backtraces)
497<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
498crashing if an exception is raised. Workaround: do not use -E.</li>
499<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
500or finish at a non-byte offset</a> in a record. Workaround: do not pack records
501or use representation clauses that result in a field of a non-discrete type
502starting or finishing in the middle of a byte.</li>
503<li>The lli interpreter <a href="http://llvm.org/PR2009">considers 'main'
504as generated by the Ada binder to be invalid</a>.
505Workaround: hand edit the file to use pointers for argv and envp rather than
506integers.</li>
507<li>The -fstack-check option <a href="http://llvm.org/PR2008">is ignored</a>.</li>
508</ul>
509</div>
510
511<!-- ======================================================================= -->
512<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame^]513 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]514</div>
515
516<div class="doc_text">
517
518<ul>
519<li>The llvm-gcc 4.2 gfortran front-end supports a broad range of Fortran code, but does
520<a href="http://llvm.org/PR1971">not support EQUIVALENCE yet</a>.</li>
521</ul>
522</div>
523
524
Chris Lattnerb62a5f02005-05-15 16:01:20 +0000[diff] [blame]525
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]526<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]527<div class="doc_section">
528 <a name="additionalinfo">Additional Information</a>
529</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]530<!-- *********************************************************************** -->
531
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]532<div class="doc_text">
533
Chris Lattnercb5596d2005-05-16 17:13:10 +0000[diff] [blame]534<p>A wide variety of additional information is available on the <a
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]535href="http://llvm.org">LLVM web page</a>, in particular in the <a
536href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]537contains versions of the API documentation which is up-to-date with the
538Subversion version of the source code.
Misha Brukman96158092005-03-30 19:14:24 +0000[diff] [blame]539You can access versions of these documents specific to this release by going
540into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]541
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]542<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]543us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]544lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]545
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]546</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]547
548<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]549
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]550<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]551<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000[diff] [blame]552 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]553 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
554 <a href="http://validator.w3.org/check/referer"><img
Chris Lattner458e79f2008-02-10 08:18:42 +0000[diff] [blame]555 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]556
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]557 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]558 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]559</address>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]560
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]561</body>
562</html>