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4<head>
Reid Spencer6454ed32004-11-18 18:38:58 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]6 <link rel="stylesheet" href="llvm.css" type="text/css">
Reid Spencerbb9fd302006-11-01 16:15:04 +0000[diff] [blame]7 <title>LLVM 1.9 Release Notes</title>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]8</head>
9<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]10
Reid Spencerbb9fd302006-11-01 16:15:04 +0000[diff] [blame]11<div class="doc_title">LLVM 1.9 Release Notes</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]12
13<ol>
Misha Brukman500bc302003-11-22 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 Lattner4b538b92004-04-30 22:17:12 +0000[diff] [blame]16 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]18 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]19 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]20</ol>
21
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]22<div class="doc_author">
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]23 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]24</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]25
26<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]27<div class="doc_section">
28 <a name="intro">Introduction</a>
29</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]30<!-- *********************************************************************** -->
31
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]32<div class="doc_text">
33
34<p>This document contains the release notes for the LLVM compiler
Reid Spencerbb9fd302006-11-01 16:15:04 +0000[diff] [blame]35infrastructure, release 1.9. Here we describe the status of LLVM, including any
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]36known problems and major improvements from the previous release. The most
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]37up-to-date version of this document (corresponding to LLVM CVS) can be found
38on the <a
Chris Lattnerc30c5c72005-11-08 21:29:17 +0000[diff] [blame]39href="http://llvm.org/releases/">LLVM releases web site</a>. If you are
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]40not reading this on the LLVM web pages, you should probably go there because
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]41this document may be updated after the release.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]42
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]43<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]44release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]45web 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 +0000[diff] [blame]47list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]48
Chris Lattner78bf32b2004-12-09 22:22:58 +0000[diff] [blame]49<p>Note that if you are reading this file from CVS or the main LLVM web page,
50this document applies to the <i>next</i> release, not the current one. To see
51the release notes for the current or previous releases, see the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]52href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]53
54</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]55
56<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]57<div class="doc_section">
58 <a name="whatsnew">What's New?</a>
59</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]60<!-- *********************************************************************** -->
61
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]62<div class="doc_text">
63
Reid Spencerbb9fd302006-11-01 16:15:04 +0000[diff] [blame]64<p>This is the tenth public release of the LLVM Compiler Infrastructure. This
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]65release incorporates a large number of enhancements, new features, and bug
66fixes. We recommend that all users of previous LLVM versions upgrade.
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]67</p>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]68
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]69</div>
70
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]71<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]72<div class="doc_subsection">
Reid Spencerbb9fd302006-11-01 16:15:04 +0000[diff] [blame]73<a name="newfeatures">New Features in LLVM 1.9</a>
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]74</div>
Brian Gaeke6b31beb2004-01-16 21:55:04 +0000[diff] [blame]75
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]76<!--_________________________________________________________________________-->
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]77<div class="doc_subsubsection"><a name="x86-64">New X86-64 Backend</a></div>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]78<div class="doc_text">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]79<p>LLVM 1.9 now fully supports the x86-64 instruction set on Mac OS/X, and
80supports it on Linux (and other operating systems) when compiling in -static
81mode. LLVM includes JIT support for X86-64, and supports both Intel EMT-64T
82and AMD-64 architectures. The X86-64 instruction set permits addressing a
8364-bit addressing space and provides the compiler with twice the
84number of integer registers to use.</p>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]85</div>
86
87<!--_________________________________________________________________________-->
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]88<div class="doc_subsubsection"><a name="lto">Link-Time Optimization integration
89with native linkers</a></div>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]90<div class="doc_text">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]91<p>LLVM now includes <a href="LinkTimeOptimization.html">liblto</a> which can
92be used to integrate LLVM Link-Time Optimization support into a native linker.
93This allows LLVM .bc to transparently participate with linking an application,
94even when some .o files are in LLVM form and some are not.</p>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]95</div>
96
97<!--_________________________________________________________________________-->
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]98<div class="doc_subsubsection"><a name="dwarf">DWARF debugging
99support for Linux, Cygwin and MinGW on X86</a></div>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]100<div class="doc_text">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]101<p>llvm-gcc4 now supports generating debugging info for Linux, Cygwin and MinGW.
102This extends the PPC/Darwin and X86/Darwin debugging support available in the
1031.8 release. DWARF is a standard debugging format used on many platforms.</p>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]104</div>
105
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]106<!--_________________________________________________________________________-->
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]107<div class="doc_subsubsection"><a name="optimizer">Optimizer
108Improvements</a></div>
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]109<div class="doc_text">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]110<p>The mid-level optimizer is now faster and produces better code in many cases.
111 Significant changes include:</p>
112
113<ul>
114<li>LLVM includes a new 'predicate simplifier' pass, which
115 currently performs dominator tree-based optimizations.</li>
116<li>The complete loop unroll pass now supports unrolling of
117 multiple basic block loops.</li>
118<li>The 'globalopt' pass can now perform the scalar replacement of
119 aggregates transformation on some heap allocations.</li>
120<li>The globalsmodref-aa alias analysis can now track 'indirect pointer
121 globals' more accurately.</li>
122<li>The instruction combiner can now perform element propagation
123analysis of vector expressions, eliminating computation of vector elements
124that are not used.</li>
125</ul>
126
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]127</div>
128
Chris Lattner1c1a85c2006-04-19 04:02:47 +0000[diff] [blame]129<!--_________________________________________________________________________-->
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]130<div class="doc_subsubsection"><a name="codegen">Code
131Generator Enhancements</a></div>
132
Chris Lattner1c1a85c2006-04-19 04:02:47 +0000[diff] [blame]133<div class="doc_text">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]134<p>
135The LLVM Target-Independent code generator now supports more target features and
136optimizes many cases more aggressively. New features include:
137</p>
138
139<ul>
140<li>LLVM now includes a late branch folding pass which optimizes code
141 layout, performs several branch optzns, and deletes unreachable code.</li>
142<li>The code generator now support targets that have pre/post-increment
143 addressing modes.</li>
144<li>LLVM now supports dynamically-loadable register allocators and
145 schedulers.</li>
146<li>LLVM 1.9 includes several improvements to inline asm support,
147 including support for new constraints and modifiers.</li>
148<li>The register coalescer is now more aggressive than before,
149 allowing it to eliminate more copies.</li>
150</ul>
151
152<p>In addition, the LLVM target description format has itself been extended in
153 several ways:</p>
154
155<ul>
156<li>tblgen now allows definition of '<a
157 href="TableGenFundamentals.html#multiclass">multiclasses</a>' which can be
158 used to factor instruction patterns more aggressively in .td files.</li>
159<li>LLVM has a new TargetAsmInfo class which captures a variety of
160 information about the target assembly language format.</li>
161<li>.td files now support "<tt>${:foo}</tt>" syntax for encoding
162 subtarget-specific assembler syntax into instruction descriptions.</li>
163</ul>
164
165<p>Further, several significant target-specific enhancements are included in
166LLVM 1.9:</p>
167
168<ul>
169<li>The LLVM ARM backend now supports more instructions
170 and the use of a frame pointer. It is now possible to build
171 libgcc and a simple cross compiler, but it is not considered "complete" yet.
172 </li>
173<li>LLVM supports the Win32 dllimport/dllexport linkage and
174 stdcall/fastcall calling conventions.</li>
175</ul>
176
Chris Lattner1c1a85c2006-04-19 04:02:47 +0000[diff] [blame]177</div>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]178
179<!--_________________________________________________________________________-->
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]180<div class="doc_subsubsection"><a name="other">Other Improvements</a></div>
Chris Lattner58504a62006-02-05 06:39:36 +0000[diff] [blame]181<div class="doc_text">
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]182<p>This release includes many other improvements, including improvements to
183 the optimizers and code generators (improving the generated code) changes to
184 speed up the compiler in many ways (improving algorithms and fine tuning
185 code), and changes to reduce the code size of the compiler itself.</p>
186
187<p>More specific changes include:</p>
188
Chris Lattner58504a62006-02-05 06:39:36 +0000[diff] [blame]189<ul>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]190<li>The llvm-test framework now supports SPEC2006.</li>
191<li>LLVM now includes a <a href="GetElementPtr.html">FAQ about the
192<tt>getelementptr</tt> instruction</a>.</li>
193<li>Bugpoint now supports a new "<tt>-find-bugs</tt>" mode. This mode makes
194 bugpoint permute pass sequences to try to expose bugs due to pass
195 sequencing.</li>
196<li>The JIT now supports lazily streaming code from multiple modules at a
197 time, implicitly linking the code as it goes.</li>
Chris Lattner58504a62006-02-05 06:39:36 +0000[diff] [blame]198</ul>
199</div>
John Criswelle531ec52005-06-29 16:22:34 +0000[diff] [blame]200
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]201<!--=========================================================================-->
202<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]203<a name="apichanges">Significant API Changes in LLVM 1.9</a>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]204</div>
205
206<div class="doc_text">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]207
208<p>Several significant API changes have been made. If you are maintaining
209out-of-tree code, please be aware that:</p>
210
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]211<ul>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]212<li>The ConstantSInt and ConstantUInt classes have been merged into the
213 ConstantInt class.</li>
214<li><p>As a step towards making LLVM's integer types signless, several new
215instructions have been added to LLVM. The <tt>Div</tt> instruction is now
216<tt>UDiv</tt>, <tt>SDiv</tt>, and <tt>FDiv</tt>. The <tt>Rem</tt> instruction
217is now <tt>URem</tt>, <tt>SRem</tt> and <tt>FRem</tt>. See the
218<a href="LangRef.html">Language Reference</a> for details on these new
219instructions.</p>
220<li><p><tt>ConstantBool::True</tt> and <tt>ConstantBool::False</tt> have been
221 renamed to <tt>ConstantBool::getTrue()</tt> and
222 <tt>ConstantBool::getFalse()</tt>.</p></li>
223<li>The 'analyze' tool has been merged into the 'opt' tool.</li>
224
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]225</ul>
226</div>
227
228
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]229<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]230<div class="doc_section">
231 <a name="portability">Portability and Supported Platforms</a>
232</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]233<!-- *********************************************************************** -->
234
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]235<div class="doc_text">
236
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]237<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]238
239<ul>
Reid Spencer00812e22005-05-17 02:47:27 +0000[diff] [blame]240 <li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
241 (and probably other unix-like systems).</li>
Chris Lattner7ea41e32006-08-09 04:10:32 +0000[diff] [blame]242<li>Intel and AMD machines running on Win32 using MinGW libraries (native)</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]243<li>Sun UltraSPARC workstations running Solaris 8.</li>
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]244<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
245 support is available for native builds with Visual C++).</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]246<li>PowerPC and X86-based Mac OS X systems, running 10.2 and above in 32-bit and
247 64-bit modes.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]248<li>Alpha-based machines running Debian GNU/Linux.</li>
249<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]250</ul>
251
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]252<p>The core LLVM infrastructure uses
253<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
254to the machine and operating system on which it is built. However, minor
255porting may be required to get LLVM to work on new platforms. We welcome your
256portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]257
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]258</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]259
260<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]261<div class="doc_section">
262 <a name="knownproblems">Known Problems</a>
263</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]264<!-- *********************************************************************** -->
265
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]266<div class="doc_text">
267
268<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]269component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]270sections. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]271href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]272there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]273
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]274</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]275
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]276<!-- ======================================================================= -->
277<div class="doc_subsection">
278 <a name="experimental">Experimental features included with this release</a>
279</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]280
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]281<div class="doc_text">
282
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]283<p>The following components of this LLVM release are either untested, known to
284be broken or unreliable, or are in early development. These components should
285not be relied on, and bugs should not be filed against them, but they may be
286useful to some people. In particular, if you would like to work on one of these
Chris Lattner49e693e2006-08-09 04:08:52 +0000[diff] [blame]287components, 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 +0000[diff] [blame]288
289<ul>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]290<li>The <tt>-cee</tt> pass is known to be buggy, and may be removed in in a
291 future release.</li>
Chris Lattner58504a62006-02-05 06:39:36 +0000[diff] [blame]292<li>The IA64 code generator is experimental.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]293<li>The ARM code generator is experimental.</li>
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]294<li>The Alpha JIT is experimental.</li>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]295<li>"<tt>-filetype=asm</tt>" (the default) is the only supported value for the
296 <tt>-filetype</tt> llc option.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]297</ul>
298
299</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]300
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]301<!-- ======================================================================= -->
302<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]303 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]304</div>
305
306<div class="doc_text">
307
308<ul>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]309<li>The X86 backend does not yet support <a href="http://llvm.org/PR879">inline
310 assembly that uses the X86 floating point stack</a>. See the <a href="<a
311 href="http://llvm.org/PR879">bug</a> for details on workarounds on
312 Linux.</li>
313</ul>
314
315</div>
316
317<!-- ======================================================================= -->
318<div class="doc_subsection">
319 <a name="ppc-be">Known problems with the PowerPC back-end</a>
320</div>
321
322<div class="doc_text">
323
324<ul>
325<li><a href="http://llvm.org/PR642">PowerPC backend does not correctly
326implement ordered FP comparisons</a>.</li>
327<li>The 64-bit PowerPC backend is not fully stable. If you desire PPC64 support,
328 please use mainline CVS LLVM, which has several important bug fixes.</li>
329</ul>
330
331</div>
332
333<!-- ======================================================================= -->
334<div class="doc_subsection">
335 <a name="sparc-be">Known problems with the SPARC back-end</a>
336</div>
337
338<div class="doc_text">
339
340<ul>
341<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
342 support the 64-bit SPARC ABI (-m64).</li>
343</ul>
344
345</div>
346
347<!-- ======================================================================= -->
348<div class="doc_subsection">
349 <a name="c-be">Known problems with the C back-end</a>
350</div>
351
352<div class="doc_text">
353
354<ul>
355
356<li>The C back-end produces code that violates the ANSI C Type-Based Alias
357Analysis rules. As such, special options may be necessary to compile the code
358(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
359problem probably cannot be fixed.</li>
360
361<li><a href="http://llvm.org/PR56">Zero arg vararg functions are not
362supported</a>. This should not affect LLVM produced by the C or C++
363frontends.</li>
364
365<li>The C backend does not correctly implement the <a
366href="LangRef.html#i_stacksave"><tt>llvm.stacksave</tt></a> or
367<a href="LangRef.html#i_stackrestore"><tt>llvm.stackrestore</tt></a>
368intrinsics. This means that some code compiled by it can run out of stack
369space if they depend on these (e.g. C99 varargs).</li>
370
371<li><a href="http://llvm.org/PR802">The C backend does not support inline
372 assembly code</a>.</li>
373</ul>
374
375</div>
376
377<!-- ======================================================================= -->
378<div class="doc_subsection">
379 <a name="alpha-be">Known problems with the Alpha back-end</a>
380</div>
381
382<div class="doc_text">
383
384<ul>
385
386<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
387appropriate nops inserted to ensure restartability.</li>
388
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]389</ul>
390</div>
391
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]392<!-- ======================================================================= -->
393<div class="doc_subsection">
394 <a name="ia64-be">Known problems with the IA64 back-end</a>
395</div>
396
397<div class="doc_text">
398
399<ul>
400
401<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
402made where the argument is not 16-byte aligned, as required on IA64. (Strictly
403speaking this is not a bug in the IA64 back-end; it will also be encountered
404when building C++ programs using the C back-end.)</li>
405
406<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
407ABI compliant layout of v-tables</a>. In particular, it just stores function
408pointers instead of function descriptors in the vtable. This bug prevents
409mixing C++ code compiled with LLVM with C++ objects compiled by other C++
410compilers.</li>
411
412<li>There are a few ABI violations which will lead to problems when mixing LLVM
413output with code built with other compilers, particularly for floating-point
414programs.</li>
415
416<li>Defining vararg functions is not supported (but calling them is ok).</li>
417
418</ul>
419
420</div>
421
422<!-- ======================================================================= -->
423<div class="doc_subsection">
424 <a name="arm-be">Known problems with the ARM back-end</a>
425</div>
426
427<div class="doc_text">
428
429<ul>
430<li>The ARM backend is currently in early development stages, it is not
431ready for production use.</li>
432</ul>
433
434</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]435
436<!-- ======================================================================= -->
437<div class="doc_subsection">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]438 <a name="core">Known problems with the LLVM Core</a>
439</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]440
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]441<div class="doc_text">
442
443<ul>
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]444 <li>In the JIT, <tt>dlsym()</tt> on a symbol compiled by the JIT will not
445 work.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]446</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]447</div>
448
449<!-- ======================================================================= -->
450<div class="doc_subsection">
451 <a name="c-fe">Known problems with the C front-end</a>
452</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]453
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]454<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]455<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]456
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]457<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]458
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]459<p>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]460
461<p>llvm-gcc4 is far more stable and produces better code than llvm-gcc3, but
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]462does not currently support <a href="http://llvm.org/PR869">Link-Time
463Optimization</a> or <a href="http://llvm.org/PR870">C++ Exception Handling</a>,
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]464which llvm-gcc3 does.</p>
465
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]466<p>llvm-gcc4 does not support the <a href="http://llvm.org/PR947">GCC indirect
467goto extension</a>, but llvm-gcc3 does.</p>
468
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]469</div>
470
471<!-- _______________________________________________________________________ -->
472<div class="doc_subsubsection">
473 Notes
474</div>
475
476<div class="doc_text">
477
478<ul>
479
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]480<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]481support for floating point data types of any size other than 32 and 64
482bits.</li>
483
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]484<li>Although many GCC extensions are supported, some are not. In particular,
485 the following extensions are known to <b>not be</b> supported:
486 <ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]487 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]488 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html#Nested%20Functions">Nested Functions</a>: As in Algol and Pascal, lexical scoping of functions.</li>
489 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
Tanya Lattner014e5f52004-12-08 18:25:34 +0000[diff] [blame]490 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]491 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]492 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]493
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]494 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]495 attribute means that the LLVM compiler ignores the presence of the attribute,
496 but the code should still work. An unsupported attribute is one which is
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]497 ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]498 the program.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]499
500 <ol>
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.<br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]503 Supported, but allocated stack space is not freed until the function returns (noted above).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]504
505 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]506
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]507 Declaring that functions have no side effects or that they can never
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]508 return.<br>
509
510 <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]511 <tt>noreturn</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
Chris Lattneraef8c642005-12-05 05:23:06 +0000[diff] [blame]512 <tt>unused</tt>, <tt>used</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]513 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
514
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]515 <b>Ignored:</b> <tt>noinline</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]516 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
517 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
518
Chris Lattneraef8c642005-12-05 05:23:06 +0000[diff] [blame]519 <b>Unsupported:</b> <tt>section</tt>, <tt>alias</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]520 <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
521 <tt>fastcall</tt>, all other target specific attributes</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]522
523 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
524 Specifying attributes of variables.<br>
525 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
526 <tt>deprecated</tt>, <tt>transparent_union</tt>,
Chris Lattneraef8c642005-12-05 05:23:06 +0000[diff] [blame]527 <tt>unused</tt>, <tt>used</tt>, <tt>weak</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]528
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]529 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
530 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
531 <tt>vector_size</tt>, <tt>dllimport</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]532 <tt>dllexport</tt>, all target specific attributes.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]533
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]534 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.<br>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]535 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]536 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]537
538 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
539 all target specific attributes.</li>
540
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]541 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
542 Other built-in functions.<br>
543 We support all builtins which have a C language equivalent (e.g.,
544 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
545 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Chris Lattnerceebeb62004-06-18 06:26:29 +0000[diff] [blame]546 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
547 (currently ignored). We also support builtins for ISO C99 floating
Chris Lattner7939b782005-05-07 02:21:21 +0000[diff] [blame]548 point comparison macros (e.g., <tt>__builtin_islessequal</tt>),
549 <tt>__builtin_prefetch</tt>, <tt>__builtin_popcount[ll]</tt>,
550 <tt>__builtin_clz[ll]</tt>, and <tt>__builtin_ctz[ll]</tt>.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]551 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]552
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]553 <p>The following extensions <b>are</b> known to be supported:</p>
554
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]555 <ol>
Chris Lattner7fe97dd2004-03-16 08:54:07 +0000[diff] [blame]556 <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 +0000[diff] [blame]557 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
558 <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 +0000[diff] [blame]559 <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 +0000[diff] [blame]560 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
561 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
562 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
563 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
564 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
565 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
566 <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>
567 <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 +0000[diff] [blame^]568 <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>
569 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
570 <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>
571 <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>
572 <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>
573 <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 +0000[diff] [blame]574 <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 +0000[diff] [blame]575 <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 +0000[diff] [blame]576 <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 +0000[diff] [blame]577 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
578or arrays as values.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]579 <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 +0000[diff] [blame]580 <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 +0000[diff] [blame]581 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
582 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
583 <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 +0000[diff] [blame]584 <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 +0000[diff] [blame]585 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
586 <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>
587 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
588 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
589 <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>
590 <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>
591 <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 +0000[diff] [blame]592 <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 +0000[diff] [blame]593 <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>
594 <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 +0000[diff] [blame]595 </ol></li>
596
597</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]598
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]599<p>If you run into GCC extensions which have not been included in any of these
600lists, please let us know (also including whether or not they work).</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]601
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]602</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]603
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]604<!-- ======================================================================= -->
605<div class="doc_subsection">
606 <a name="c++-fe">Known problems with the C++ front-end</a>
607</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]608
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]609<div class="doc_text">
610
Reid Spencere09ca642004-12-07 08:39:08 +0000[diff] [blame]611<p>For this release, the C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]612tested and works for a number of non-trivial programs, including LLVM
613itself.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]614
615</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]616
617<!-- _______________________________________________________________________ -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]618<div class="doc_subsubsection">
619 Notes
620</div>
621
622<div class="doc_text">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]623<ul>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]624<li>llvm-gcc4 does not support C++ exception handling at all yet.</li>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]625
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]626<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]627 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]628 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]629 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]630 better than most compilers).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]631
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]632<li>The LLVM C++ front-end follows the <a
633 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
634 This document, which is not Itanium specific, specifies a standard for name
635 mangling, class layout, v-table layout, RTTI formats, and other C++
636 representation issues. Because we use this API, code generated by the LLVM
637 compilers should be binary compatible with machine code generated by other
638 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame^]639 <i>However</i>, the exception handling mechanism used by llvm-gcc3 is very
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]640 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]641 interact correctly</b>. </li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]642
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]643</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]644
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]645</div>
646
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]647
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]648
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]649<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]650<div class="doc_section">
651 <a name="additionalinfo">Additional Information</a>
652</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]653<!-- *********************************************************************** -->
654
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]655<div class="doc_text">
656
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]657<p>A wide variety of additional information is available on the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]658href="http://llvm.org">LLVM web page</a>, including <a
659href="http://llvm.org/docs/">documentation</a> and <a
660href="http://llvm.org/pubs/">publications describing algorithms and
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]661components implemented in LLVM</a>. The web page also contains versions of the
662API documentation which is up-to-date with the CVS version of the source code.
663You can access versions of these documents specific to this release by going
664into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]665
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]666<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]667us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]668lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]669
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]670</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]671
672<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]673
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]674<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]675<address>
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680
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]681 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]682 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]683</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]684
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]685</body>
686</html>