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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 738bd3031cbbe54e6dc7d32e7280ea598286861a / . / docs / ReleaseNotes.html
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Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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3<html>
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">
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]7 <title>LLVM 1.7 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
Chris Lattnerc30c5c72005-11-08 21:29:17 +0000[diff] [blame]11<div class="doc_title">LLVM 1.7 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
Chris Lattnerc30c5c72005-11-08 21:29:17 +0000[diff] [blame]35infrastructure, release 1.7. 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
37up-to-date version of this document can be found on the <a
Chris Lattnerc30c5c72005-11-08 21:29:17 +0000[diff] [blame]38href="http://llvm.org/releases/">LLVM releases web site</a>. If you are
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]39not reading this on the LLVM web pages, you should probably go there because
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]40this document may be updated after the release.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]41
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]42<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]43release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]44web site</a>. If you have questions or comments, the <a
45href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]46list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]47
Chris Lattner78bf32b2004-12-09 22:22:58 +0000[diff] [blame]48<p>Note that if you are reading this file from CVS or the main LLVM web page,
49this document applies to the <i>next</i> release, not the current one. To see
50the release notes for the current or previous releases, see the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]51href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]52
53</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]54
55<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]56<div class="doc_section">
57 <a name="whatsnew">What's New?</a>
58</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]59<!-- *********************************************************************** -->
60
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]61<div class="doc_text">
62
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]63<p>This is the eighth public release of the LLVM Compiler Infrastructure. This
64release incorporates a large number of enhancements and new features,
65including vector support (Intel SSE and Altivec), a new GCC4.0-based
66C/C++ front-end, Objective C/C++ support, inline assembly support, and many
67other big features.
68</p>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]69
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]70</div>
71
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]72<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]73<div class="doc_subsection">
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]74<a name="newfeatures">New Features in LLVM 1.7</a>
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]75</div>
Brian Gaeke6b31beb2004-01-16 21:55:04 +0000[diff] [blame]76
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]77<!--_________________________________________________________________________-->
78<div class="doc_subsubsection"><a name="llvmgcc4">GCC4.0-based llvm-gcc
79front-end</a></div>
80
81<div class="doc_text">
82
83<p>LLVM 1.8 includes a brand new llvm-gcc, based on GCC 4.0.1. This version
84of llvm-gcc solves many serious long-standing problems with llvm-gcc, including
85all of those blocked by the <a href="http://llvm.org/PR498">llvm-gcc 4 meta
86bug</a>. In addition, llvm-gcc4 implements support for many new features,
87including GCC inline assembly, generic vector support, SSE and Altivec
88intrinsics, and several new GCC attributes. In addition, llvm-gcc4 is
89significantly faster than llvm-gcc3, respects -O options, its -c/-S options
90correspond to GCC's (they emit native code).</p>
91
92<p>If you can use it, llvm-gcc4 is offers significant new functionality, and we
93hope that it will replace llvm-gcc3 completely in a future release.
94Unfortunately, it does not currently support C++ exception handling at all, and
95it only works on Apple Mac OS/X machines with X86 or PowerPC processors.
96</p>
97
98</div>
99
100<!--_________________________________________________________________________-->
101<div class="doc_subsubsection"><a name="inlineasm">Inline Assembly
102Support</a></div>
103
104<div class="doc_text">
105
106<p>The LLVM IR and llvm-gcc4 front-end now fully support arbitrary GCC <a
107href="LangRef.html#inlineasm">inline assembly</a>. The LLVM X86 and PowerPC
108code generators have initial support for it,
109being able to compile basic statements, but are missing some features. Please
110report any inline asm statements that crash the compiler or that are miscompiled
111as bugs.</p>
112
113</div>
114
115<!--_________________________________________________________________________-->
116<div class="doc_subsubsection"><a name="newsparc">New SPARC backend</a></div>
117
118<div class="doc_text">
119
120<p>LLVM 1.7 includes a new, fully functional, SPARC backend built in the
121target-independent code generator. This SPARC backend includes support for
122SPARC V8 and SPARC V9 subtargets (controlling whether V9 features can be used),
123and targets the 32-bit SPARC ABI.</p>
124
125<p>The LLVM 1.7 release is the last release that will include the LLVM "SparcV9"
126backend, which was the very first LLVM native code generator. In 1.8, it will
127be removed, replaced with the new SPARC backend.</p>
128
129</div>
130
131<!--_________________________________________________________________________-->
132<div class="doc_subsubsection"><a name="genvector">Generic Vector Support
133</a></div>
134
135<div class="doc_text">
136
137<p>LLVM now includes significantly extended support for SIMD vectors in its
138core instruction set. It now includes three new instructions for manipulating
139vectors: <a href="LangRef.html#i_extractelement"><tt>extractelement</tt></a>,
140<a href="LangRef.html#i_insertelement"><tt>insertelement</tt></a>, and
141<a href="LangRef.html#i_shufflevector"><tt>shufflevector</tt></a>. Further,
142many bugs in vector handling have been fixed, and vectors are now supported by
143the target-independent code generator. For example, if a vector operation is
144not supported by a particular target, it will be correctly broken down and
145executed as scalar operations.</p>
146
147<p>Because llvm-gcc3 does not support GCC generic vectors or vector intrinsics,
148so llvm-gcc4 must be used.</p>
149</div>
150
151
152<!--_________________________________________________________________________-->
153<div class="doc_subsubsection"><a name="ssealtivec">Intel SSE and PowerPC
154Altivec support
155</a></div>
156
157<div class="doc_text">
158
159<p>The LLVM X86 backend now supports Intel SSE 1, 2, and 3, and now uses scalar
160SSE operations to implement scalar floating point math when the target supports
161SSE1 (for floats) or SSE2 (for doubles). Vector SSE instructions are generated
162by llvm-gcc4 when the generic vector mechanism or specific SSE intrinsics are
163used.
164</p>
165
166<p>The LLVM PowerPC backend now supports the Altivec instruction set, including
167both GCC -maltivec and -faltivec modes. Altivec instructions are generated
168by llvm-gcc4 when the generic vector mechanism or specific Altivec intrinsics
169are used.
170</p>
171
172</div>
173
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame^]174<!--_________________________________________________________________________-->
175<div class="doc_subsubsection"><a name="othernew">Optimizer
176Improvements</a></div>
177
178<div class="doc_text">
179<ul>
180<li>The Loop Unswitching pass (<tt>-loop-unswitch</tt>) has had several bugs
181 fixed, has several new features, and is enabled by default in llvmgcc3
182 now.</li>
183<li>The Loop Strength Reduction pass (<tt>-loop-reduce</tt>) is now enabled for
184 the X86 backend.</li>
185<li>The Instruction Combining pass (<tt>-instcombine</tt>) now includes a
186 framework and implementation for simplifying code based on whether computed
187 bits are demanded or not.</li>
188<li>The Scalar Replacement of Aggregates pass (<tt>-scalarrepl</tt>) can now
189 promote simple unions to registers.</li>
190<li>Several LLVM passes are <a href="http://llvm.org/PR681">significantly
191faster</a>.</li>
192</ul>
193</div>
194
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]195
196<!--_________________________________________________________________________-->
197<div class="doc_subsubsection"><a name="othernew">Other New Features</a></div>
198
Chris Lattner58504a62006-02-05 06:39:36 +0000[diff] [blame]199<div class="doc_text">
200<ul>
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame^]201<li>LLVM now supports first class global ctor/dtor initialization lists, no
202 longer forcing targets to use "__main".</li>
203<li>LLVM supports assigning globals and functions to a particular section
204 in the result executable using the GCC section attribute.</li>
205<li><a href="ExtendingLLVM.html">Adding intrinsics to LLVM</a> is now
206significantly easier.</li>
207<li>llvmgcc4 now fully supports C99 Variable Length Arrays, including dynamic
208 stack deallocation.</li>
209
Chris Lattner58504a62006-02-05 06:39:36 +0000[diff] [blame]210</ul>
211</div>
John Criswelle531ec52005-06-29 16:22:34 +0000[diff] [blame]212
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]213
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]214<!--=========================================================================-->
215<div class="doc_subsection">
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]216<a name="changes">Significant Changes in LLVM 1.7</a>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]217</div>
218
219<div class="doc_text">
220<ul>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]221<li>The LLVM intrinsics used to be overloaded based on type: for example,
222 <a href="LangRef.html#int_ctpop"><tt>llvm.ctpop</tt></a> could work with any
223 integer datatype. They are now separated into different intrinsics with
224 suffixes to denote their argument type (e.g. <tt>llvm.ctpop.i32</tt>)). Old
225 LLVM .ll and .bc files that use these intrinsics will continue to work with
226 new LLVM versions (they are transparently upgraded by the parsers), but will
227 cause a warning to be emitted.</li>
228<li>The <tt>llvm.readport</tt>, <tt>llvm.writeport</tt>, <tt>llvm.readio</tt>,
229 and <tt>llvm.writeio</tt> intrinsics have been removed. The first two
230 were ever only supported by the X86 backend, the last two were never
231 correctly supported by any target, and none were accessible through the
232 C front-end. Inline assembly support can now be used to
233 implement these operations.</li>
234<li>The <tt>llvm-db</tt> tool had basic support for stepping through code, which
235 used the JIT. This code has been removed, and DWARF emission support added
236 instead. <tt>llvm-db</tt> still exists in CVS if someone wanted to write a
237 <tt>ptrace</tt> backend for it.</li>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]238</ul>
239</div>
240
241
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]242<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]243<div class="doc_section">
244 <a name="portability">Portability and Supported Platforms</a>
245</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]246<!-- *********************************************************************** -->
247
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]248<div class="doc_text">
249
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]250<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]251
252<ul>
Reid Spencer00812e22005-05-17 02:47:27 +0000[diff] [blame]253 <li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
254 (and probably other unix-like systems).</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]255<li>Sun UltraSPARC workstations running Solaris 8.</li>
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]256<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
257 support is available for native builds with Visual C++).</li>
Chris Lattnerfeaf9602005-10-29 05:14:01 +0000[diff] [blame]258<li>PowerPC and X86-based Mac OS X systems, running 10.2 and above.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]259<li>Alpha-based machines running Debian GNU/Linux.</li>
260<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]261</ul>
262
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]263<p>The core LLVM infrastructure uses
264<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
265to the machine and operating system on which it is built. However, minor
266porting may be required to get LLVM to work on new platforms. We welcome your
267portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]268
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]269</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]270
271<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]272<div class="doc_section">
273 <a name="knownproblems">Known Problems</a>
274</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]275<!-- *********************************************************************** -->
276
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]277<div class="doc_text">
278
279<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]280component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]281sections. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]282href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]283there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]284
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]285</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]286
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]287<!-- ======================================================================= -->
288<div class="doc_subsection">
289 <a name="experimental">Experimental features included with this release</a>
290</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]291
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]292<div class="doc_text">
293
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]294<p>The following components of this LLVM release are either untested, known to
295be broken or unreliable, or are in early development. These components should
296not be relied on, and bugs should not be filed against them, but they may be
297useful to some people. In particular, if you would like to work on one of these
298components, please contact us on the llvmdev list.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]299
300<ul>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]301<li>The <tt>-cee</tt> pass is known to be buggy, and may be removed in in a
302 future release.</li>
Chris Lattner58504a62006-02-05 06:39:36 +0000[diff] [blame]303<li>The IA64 code generator is experimental.</li>
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]304<li>The Alpha JIT is experimental.</li>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]305<li>"<tt>-filetype=asm</tt>" (the default) is the only supported value for the
306 <tt>-filetype</tt> llc option.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]307</ul>
308
309</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]310
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]311<!-- ======================================================================= -->
312<div class="doc_subsection">
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]313 <a name="build">Known problems with the Build System</a>
314</div>
315
316<div class="doc_text">
317
318<ul>
319 <li>The <a href="http://llvm.org/PR656">configure script sometimes fails on Solaris/Sparc</a>. A work around is documented in <a href="http://llvm.org/PR656">PR656.</a></li>
320</ul>
321</div>
322
323
324<!-- ======================================================================= -->
325<div class="doc_subsection">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]326 <a name="core">Known problems with the LLVM Core</a>
327</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]328
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]329<div class="doc_text">
330
331<ul>
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]332 <li>In the JIT, <tt>dlsym()</tt> on a symbol compiled by the JIT will not
333 work.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]334</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]335</div>
336
337<!-- ======================================================================= -->
338<div class="doc_subsection">
339 <a name="c-fe">Known problems with the C front-end</a>
340</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]341
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]342<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]343<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]344
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]345<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]346
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]347<p>
348llvm-gcc3 has many significant problems that are fixed by llvm-gcc4. See
349 those blocked on the <a href="http://llvm.org/PR498">llvm-gcc4 meta bug</a>.
350Two signicant ones include:</p>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]351
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]352<ul>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]353<li>With llvm-gcc3,
354 C99 variable sized arrays do not release stack memory when they go out of
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]355 scope. Thus, the following program may run out of stack space:
356<pre>
357 for (i = 0; i != 1000000; ++i) {
358 int X[n];
359 foo(X);
360 }
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]361</pre></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]362
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]363<li>With llvm-gcc3, Initialization of global union variables can only be done <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]364href="http://llvm.org/PR162">with the largest union member</a>.</li>
Chris Lattnerf580cdc2004-03-16 21:39:04 +0000[diff] [blame]365
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]366</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]367</div>
368
369<!-- _______________________________________________________________________ -->
370<div class="doc_subsubsection">
371 Notes
372</div>
373
374<div class="doc_text">
375
376<ul>
377
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]378<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]379support for floating point data types of any size other than 32 and 64
380bits.</li>
381
382<li>The following Unix system functionality has not been tested and may not
383work:
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]384 <ol>
385 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
386 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
387 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
388 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
389 - These functions have not been tested.
390 </ol></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]391
392<li>Although many GCC extensions are supported, some are not. In particular,
393 the following extensions are known to <b>not be</b> supported:
394 <ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]395 <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]396 <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>
397 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
398 <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>
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]399 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]400 <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>
401 <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>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]402 <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>
403 <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>
Tanya Lattner014e5f52004-12-08 18:25:34 +0000[diff] [blame]404 <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]405 <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]406 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]407
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]408 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]409 attribute means that the LLVM compiler ignores the presence of the attribute,
410 but the code should still work. An unsupported attribute is one which is
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]411 ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]412 the program.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]413
414 <ol>
415 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
416 Arrays whose length is computed at run time.<br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]417 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]418
419 <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]420
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]421 Declaring that functions have no side effects or that they can never
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]422 return.<br>
423
424 <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]425 <tt>noreturn</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
Chris Lattneraef8c642005-12-05 05:23:06 +0000[diff] [blame]426 <tt>unused</tt>, <tt>used</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]427 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
428
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]429 <b>Ignored:</b> <tt>noinline</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]430 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
431 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
432
Chris Lattneraef8c642005-12-05 05:23:06 +0000[diff] [blame]433 <b>Unsupported:</b> <tt>section</tt>, <tt>alias</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]434 <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
435 <tt>fastcall</tt>, all other target specific attributes</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]436
437 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
438 Specifying attributes of variables.<br>
439 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
440 <tt>deprecated</tt>, <tt>transparent_union</tt>,
Chris Lattneraef8c642005-12-05 05:23:06 +0000[diff] [blame]441 <tt>unused</tt>, <tt>used</tt>, <tt>weak</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]442
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]443 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
444 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
445 <tt>vector_size</tt>, <tt>dllimport</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]446 <tt>dllexport</tt>, all target specific attributes.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]447
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]448 <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]449 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]450 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]451
452 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
453 all target specific attributes.</li>
454
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]455 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
456 Other built-in functions.<br>
457 We support all builtins which have a C language equivalent (e.g.,
458 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
459 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Chris Lattnerceebeb62004-06-18 06:26:29 +0000[diff] [blame]460 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
461 (currently ignored). We also support builtins for ISO C99 floating
Chris Lattner7939b782005-05-07 02:21:21 +0000[diff] [blame]462 point comparison macros (e.g., <tt>__builtin_islessequal</tt>),
463 <tt>__builtin_prefetch</tt>, <tt>__builtin_popcount[ll]</tt>,
464 <tt>__builtin_clz[ll]</tt>, and <tt>__builtin_ctz[ll]</tt>.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]465 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]466
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]467 <p>The following extensions <b>are</b> known to be supported:</p>
468
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]469 <ol>
Chris Lattner7fe97dd2004-03-16 08:54:07 +0000[diff] [blame]470 <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]471 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
472 <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]473 <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]474 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
475 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
476 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
477 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
478 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
479 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
480 <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>
481 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
482 <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]483 <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]484 <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]485 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
486or arrays as values.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]487 <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]488 <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]489 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
490 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
491 <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]492 <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]493 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
494 <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>
495 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
496 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
497 <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>
498 <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>
499 <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]500 <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]501 <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>
502 <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]503 </ol></li>
504
505</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]506
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]507<p>If you run into GCC extensions which have not been included in any of these
508lists, please let us know (also including whether or not they work).</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]509
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]510</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]511
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]512<!-- ======================================================================= -->
513<div class="doc_subsection">
514 <a name="c++-fe">Known problems with the C++ front-end</a>
515</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]516
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]517<div class="doc_text">
518
Reid Spencere09ca642004-12-07 08:39:08 +0000[diff] [blame]519<p>For this release, the C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]520tested and works for a number of non-trivial programs, including LLVM
521itself.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]522
523</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]524
525<!-- _______________________________________________________________________ -->
Chris Lattner3a51be12004-02-14 04:12:41 +0000[diff] [blame]526<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]527
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]528<div class="doc_text">
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]529
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]530<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]531<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]532 front-end</a>.</li>
Chris Lattner7962f712004-07-17 02:04:41 +0000[diff] [blame]533
Chris Lattnerd5713882004-08-02 20:28:44 +0000[diff] [blame]534</ul>
535
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]536</div>
537
538<!-- _______________________________________________________________________ -->
539<div class="doc_subsubsection">
540 Notes
541</div>
542
543<div class="doc_text">
544
545<ul>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]546
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]547<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]548 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]549 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]550 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]551 better than most compilers).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]552
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]553<li>The LLVM C++ front-end follows the <a
554 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
555 This document, which is not Itanium specific, specifies a standard for name
556 mangling, class layout, v-table layout, RTTI formats, and other C++
557 representation issues. Because we use this API, code generated by the LLVM
558 compilers should be binary compatible with machine code generated by other
559 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
560 <i>However</i>, the exception handling mechanism used by LLVM is very
561 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]562 interact correctly</b>. </li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]563
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]564</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]565
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]566</div>
567
568<!-- ======================================================================= -->
569<div class="doc_subsection">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]570 <a name="c-be">Known problems with the C back-end</a>
571</div>
572
573<div class="doc_text">
574
575<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]576
577<li>The C back-end produces code that violates the ANSI C Type-Based Alias
578Analysis rules. As such, special options may be necessary to compile the code
579(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]580problem probably cannot be fixed.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]581
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]582<li><a href="http://llvm.org/PR56">Zero arg vararg functions are not
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]583supported</a>. This should not affect LLVM produced by the C or C++
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]584frontends.</li>
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]585
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]586<li>The C backend does not correctly implement the <a
587href="LangRef.html#i_stacksave"><tt>llvm.stacksave</tt></a> or
588<a href="LangRef.html#i_stackrestore"><tt>llvm.stackrestore</tt></a>
589intrinsics. This means that some code compiled by it can run out of stack
590space if they depend on these (e.g. C99 varargs).</li>
591
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]592</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]593
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]594</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]595
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000[diff] [blame]596<!-- ======================================================================= -->
597<div class="doc_subsection">
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]598 <a name="x86-be">Known problems with the X86 back-end</a>
599</div>
600
601<div class="doc_text">
602
603<ul>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]604<li><a href="http://llvm.org/PR736">Indirect calls crash JIT on
605Darwin/x86</a>.</li>
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]606</ul>
607
608</div>
609
610<!-- ======================================================================= -->
611<div class="doc_subsection">
612 <a name="ppc-be">Known problems with the PowerPC back-end</a>
613</div>
614
615<div class="doc_text">
616
617<ul>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]618<li><a href="http://llvm.org/PR642">PowerPC backend does not correctly
619implement ordered FP comparisons</a>.</li>
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]620</ul>
621
622</div>
623
624<!-- ======================================================================= -->
625<div class="doc_subsection">
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000[diff] [blame]626 <a name="alpha-be">Known problems with the Alpha back-end</a>
627</div>
628
629<div class="doc_text">
630
631<ul>
632
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]633<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
634appropriate nops inserted to ensure restartability.</li>
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000[diff] [blame]635
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000[diff] [blame]636</ul>
637
638</div>
639
Duraid Madina2e36d6e2005-05-14 05:48:13 +0000[diff] [blame]640<!-- ======================================================================= -->
641<div class="doc_subsection">
642 <a name="ia64-be">Known problems with the IA64 back-end</a>
643</div>
644
645<div class="doc_text">
646
647<ul>
648
649<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
650made where the argument is not 16-byte aligned, as required on IA64. (Strictly
651speaking this is not a bug in the IA64 back-end; it will also be encountered
652when building C++ programs using the C back-end.)</li>
653
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]654<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]655ABI compliant layout of v-tables</a>. In particular, it just stores function
656pointers instead of function descriptors in the vtable. This bug prevents
657mixing C++ code compiled with LLVM with C++ objects compiled by other C++
658compilers.</li>
Duraid Madina2e36d6e2005-05-14 05:48:13 +0000[diff] [blame]659
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]660<li>There are a few ABI violations which will lead to problems when mixing LLVM
661output with code built with other compilers, particularly for floating-point
662programs.</li>
663
664<li>Defining vararg functions is not supported (but calling them is ok).</li>
Duraid Madina2e36d6e2005-05-14 05:48:13 +0000[diff] [blame]665
666</ul>
667
668</div>
669
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]670<!-- ======================================================================= -->
671<div class="doc_subsection">
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]672 <a name="sparc-be">Known problems with the SPARC back-end</a>
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]673</div>
674
675<div class="doc_text">
676
677<ul>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]678<li>None yet</li>
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]679</ul>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]680
681</div>
682
683
684<!-- ======================================================================= -->
685<div class="doc_subsection">
686 <a name="sparcv9-be">Known problems with the SparcV9 back-end</a>
687</div>
688
689<div class="doc_text">
690
691<ul>
692<li><a href="http://llvm.org/PR60">[sparcv9] SparcV9 backend miscompiles
693several programs in the LLVM test suite</a></li>
694<li>The SparcV9 backend is slated to be removed before the LLVM 1.8
695 release.</li>
696</ul>
697
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]698</div>
699
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]700<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]701<div class="doc_section">
702 <a name="additionalinfo">Additional Information</a>
703</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]704<!-- *********************************************************************** -->
705
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]706<div class="doc_text">
707
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]708<p>A wide variety of additional information is available on the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]709href="http://llvm.org">LLVM web page</a>, including <a
710href="http://llvm.org/docs/">documentation</a> and <a
711href="http://llvm.org/pubs/">publications describing algorithms and
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]712components implemented in LLVM</a>. The web page also contains versions of the
713API documentation which is up-to-date with the CVS version of the source code.
714You can access versions of these documents specific to this release by going
715into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]716
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]717<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]718us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]719lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]720
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]721</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]722
723<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]724
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]725<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]726<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]727 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]728 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
729 <a href="http://validator.w3.org/check/referer"><img
730 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
731
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]732 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]733 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]734</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]735
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]736</body>
737</html>