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gerrit-public.fairphone.software / toolchain / llvm-project / 23257069b61981d261779d55c8c71b9769eae3e4 / . / llvm / docs / ReleaseNotes.html
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Chris Lattner1a7e43c2004-04-01 00:41:31 +0000[diff] [blame]6 <title>LLVM 1.3 Release Notes</title>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]7</head>
8<body>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]9
Chris Lattner1a7e43c2004-04-01 00:41:31 +0000[diff] [blame]10<div class="doc_title">LLVM 1.3 Release Notes</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]11
12<ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]13 <li><a href="#intro">Introduction</a></li>
14 <li><a href="#whatsnew">What's New?</a></li>
Chris Lattner77a51732004-04-30 22:17:12 +0000[diff] [blame]15 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]16 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]17 <li><a href="#knownproblems">Known Problems</a>
18 <ul>
Chris Lattner1a7e43c2004-04-01 00:41:31 +0000[diff] [blame]19 <li><a href="#experimental">Experimental features included in this
20 release</a>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]21 <li><a href="#core">Known problems with the LLVM Core</a>
22 <li><a href="#c-fe">Known problems with the C Front-end</a>
23 <li><a href="#c++-fe">Known problems with the C++ Front-end</a>
24 <li><a href="#x86-be">Known problems with the X86 Back-end</a>
25 <li><a href="#sparc-be">Known problems with the Sparc Back-end</a>
26 <li><a href="#c-be">Known problems with the C back-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]27 </ul></li>
28 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]29</ol>
30
Misha Brukman7cb4e382003-11-22 01:00:11 +0000[diff] [blame]31<div class="doc_text">
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]32 <p><b>Written by the <a href="http://llvm.cs.uiuc.edu">LLVM team</a></b><p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]33</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]34
35<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]36<div class="doc_section">
37 <a name="intro">Introduction</a>
38</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]39<!-- *********************************************************************** -->
40
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]41<div class="doc_text">
42
43<p>This document contains the release notes for the LLVM compiler
Chris Lattner1a7e43c2004-04-01 00:41:31 +0000[diff] [blame]44infrastructure, release 1.3. Here we describe the status of LLVM, including any
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]45known problems and bug fixes from the previous release. The most up-to-date
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]46version of this document can be found on the <a
Chris Lattner1a7e43c2004-04-01 00:41:31 +0000[diff] [blame]47href="http://llvm.cs.uiuc.edu/releases/1.3/">LLVM 1.3 web site</a>. If you are
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]48not reading this on the LLVM web pages, you should probably go there because
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]49this document may be updated after the release.</p>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]50
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]51<p>For more information about LLVM, including information about potentially more
Chris Lattnere7525b52003-10-07 21:38:31 +0000[diff] [blame]52current releases, please check out the <a href="http://llvm.cs.uiuc.edu">main
53web site</a>. If you have questions or comments, the <a
54href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]55list</a> is a good place to send them.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]56
Chris Lattnere76e9ab2003-12-12 04:25:33 +0000[diff] [blame]57<p>Note that if you are reading this file from CVS, this document applies
58to the <i>next</i> release, not the current one. To see the release notes for
59the current or previous releases, see the <a
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]60href="http://llvm.cs.uiuc.edu/releases/">releases page</a>.</p>
61
62</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]63
64<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]65<div class="doc_section">
66 <a name="whatsnew">What's New?</a>
67</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]68<!-- *********************************************************************** -->
69
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]70<div class="doc_text">
71
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]72<p>This is the fourth public release of the LLVM compiler infrastructure. This
Chris Lattnerea309ff2004-05-04 17:04:09 +0000[diff] [blame]73release primarily improves the <a href="#codequality">performance of the
74code</a> produced by all aspects of the LLVM compiler and adds some <a
75href="#newfeatures">new features</a>, though it does <a href="#bugfix">fix a few
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]76bugs</a> as well.</p>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]77
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]78<p> At this time, LLVM is known to correctly compile and run all C &amp; C++
79SPEC CPU2000 benchmarks, the Olden benchmarks, and the Ptrdist benchmarks. It
80has also been used to compile <b>many</b> other programs. LLVM now also works
81with a broad variety of C++ programs, though it has still received less testing
82than the C front-end.</p>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]83
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]84<!--=========================================================================-->
85<div class="doc_subsubsection">
Chris Lattner8ebf2532004-02-25 16:36:51 +0000[diff] [blame]86<a name="newfeatures">This release implements the following new features:</a>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]87</div>
Chris Lattnere7525b52003-10-07 21:38:31 +0000[diff] [blame]88
89<ol>
Chris Lattner1a7e43c2004-04-01 00:41:31 +0000[diff] [blame]90<li>The LLVM <a href="LangRef.html#i_select"><tt>select</tt></a> instruction is
Chris Lattner2ad48782004-05-02 04:19:15 +0000[diff] [blame]91now fully implemented and supported by all transformations, native code
92generators, and the interpreter.</li>
Misha Brukman017f2f32004-04-19 02:56:49 +0000[diff] [blame]93<li>Bugpoint can now narrow down code-generation bugs to a loop nest, where
94before it could only narrow them down to a function being miscompiled.</li>
Brian Gaekee307f8a72004-05-04 21:22:57 +0000[diff] [blame]95<li><a href="http://llvm.cs.uiuc.edu/PR40">Bugpoint can now debug arbitrary
96modes of llc</a> and lli, by passing them command line flags (e.g.,
97<tt>-regalloc=linearscan</tt>, <tt>-enable-correct-eh-support</tt>, etc.) </li>
Chris Lattner2ad48782004-05-02 04:19:15 +0000[diff] [blame]98<li>The Control Flow Graph in the native code generators is no longer
99constrained to be the same as the CFG for the LLVM input code.</li>
100<li>The LLVM induction variable analysis routines have been rewritten.</li>
101<li>LLVM now has new loop unrolling and loop unswitching passes.</li>
102<li>The induction variable substitution pass performs linear function test
103replacement and exit value replacement optimizations.</li>
Chris Lattner592db402003-11-19 22:05:38 +0000[diff] [blame]104</ol>
Chris Lattner4491de62003-11-08 04:28:55 +0000[diff] [blame]105
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]106
107<!--=========================================================================-->
108<div class="doc_subsubsection">
109In this release, the following missing features were implemented:
110</div>
Chris Lattner4491de62003-11-08 04:28:55 +0000[diff] [blame]111
112<ol>
Misha Brukman017f2f32004-04-19 02:56:49 +0000[diff] [blame]113<li><a href="http://llvm.cs.uiuc.edu/PR82">LLVM cannot handle structures with
114more than 256 elements</a></li>
Misha Brukmane7050232004-04-19 03:01:01 +0000[diff] [blame]115<li><a href="http://llvm.cs.uiuc.edu/PR38">[bugpoint] External functions used in
116non-instruction entities, such as global constant initializer</a></li>
Reid Spencer45e25d82004-05-09 23:32:39 +0000[diff] [blame]117<li><a href="http://llvm.cs.uiuc.edu/PR178">Stacker does not handle targets
118with 64-bit pointers.</a></li>
Misha Brukmane7050232004-04-19 03:01:01 +0000[diff] [blame]119<li><a href="http://llvm.cs.uiuc.edu/PR290">Bugpoint doesn't support
120uses of external fns by immediate constant exprs</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]121</ol>
Chris Lattnere7525b52003-10-07 21:38:31 +0000[diff] [blame]122
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]123
124<!--=========================================================================-->
125<div class="doc_subsubsection">
Misha Brukman017f2f32004-04-19 02:56:49 +0000[diff] [blame]126<a name="qualityofimp">In this release, the following Quality of Implementation
127issues were fixed:</a>
Chris Lattner4df78f02003-12-20 03:42:11 +0000[diff] [blame]128</div>
129
130<ol>
Misha Brukman017f2f32004-04-19 02:56:49 +0000[diff] [blame]131<li><a href="http://llvm.cs.uiuc.edu/PR305">LLVM tools will happily spew
132bytecode onto your terminal</a></li>
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]133<li><a href="http://llvm.cs.uiuc.edu/PR329">[llvmgcc] type names are not emitted
134for structure typedefs</a></li>
Chris Lattner4df78f02003-12-20 03:42:11 +0000[diff] [blame]135</ol>
136
137<!--=========================================================================-->
138<div class="doc_subsubsection">
Chris Lattner8ebf2532004-02-25 16:36:51 +0000[diff] [blame]139In this release, the following build problems were fixed:
Brian Gaeke8b05e4f2004-01-16 21:55:04 +0000[diff] [blame]140</div>
141
142<ol>
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]143<li><a href="http://llvm.cs.uiuc.edu/PR301">Minor configure bugs with
144-disable/enable-povray and -disable-spec</a></li>
145<li><a href="http://llvm.cs.uiuc.edu/PR289">shell scripts output by gccld don't
146work if you change PATH</a></li>
Brian Gaeke8b05e4f2004-01-16 21:55:04 +0000[diff] [blame]147</ol>
148
149<!--=========================================================================-->
150<div class="doc_subsubsection">
Chris Lattner2ad48782004-05-02 04:19:15 +0000[diff] [blame]151<a name="codequality">This release includes the following Code Quality
152improvements:</a>
Chris Lattner23257062004-05-23 20:42:08 +0000[diff] [blame^]153</div>
Chris Lattner639579c2003-10-27 17:06:39 +0000[diff] [blame]154
155<ol>
Chris Lattner2ad48782004-05-02 04:19:15 +0000[diff] [blame]156<li>Fixed: <a href="http://llvm.cs.uiuc.edu/PR309">[vmcore] Code quality problem
157due to long operand of getelementptr</a></li>
Chris Lattner54dcea82004-04-13 14:43:35 +0000[diff] [blame]158
159<li>The X86 backend now generates substantially better code for 64-bit integer
160and floating point operations.</li>
161
162<li>The -inline pass no longer inlines mutually recursive functions until it
163hits the inlining threshold.</li>
164
165<li>The -inline pass no longer misses obvious inlining opportunities just
166because the callee eventually calls into an external function.</li>
167
168<li>The -simplifycfg pass can now "if convert" simple statements into the new
169<tt>select</tt> instruction.</li>
170
171<li>The -loopsimplify pass can now break <a
172href="http://llvm.cs.uiuc.edu/PR35">natural loops with multiple backedges</a>
173into multiple nested loops. This enables a variety of subsequent
174optimizations.</li>
175
176<li>The -adce pass can now eliminate calls to functions that do not not write to
177memory.</li>
178
179<li>The link-time optimizer now runs the -prune-eh pass (to remove unused
Chris Lattnerea309ff2004-05-04 17:04:09 +0000[diff] [blame]180exception handlers).</li>
Chris Lattner54dcea82004-04-13 14:43:35 +0000[diff] [blame]181
Chris Lattner2ad48782004-05-02 04:19:15 +0000[diff] [blame]182<li>The -simplifycfg pass can now eliminate simple correlated branches (such as
183"<tt>if (A &lt; B &amp;&amp; A &lt; B)</tt>", and can turn short-circuiting
184operators into the strict versions when useful (such as "<tt>if (A &lt; B || A
185&gt; C)</tt>" into "<tt>if (A &lt; B | A &gt; C)</tt>"</li>
186
Chris Lattnerea309ff2004-05-04 17:04:09 +0000[diff] [blame]187<li>LLVM now has infrastructure for (simple and sparse conditional) constant
188propagation of function calls. It currently supports a few math library
189functions like sqrt/sin/cos/etc.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]190</ol>
Chris Lattner639579c2003-10-27 17:06:39 +0000[diff] [blame]191
Reid Spencer3e58f582004-05-23 17:23:13 +0000[diff] [blame]192</div>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]193
194<!--=========================================================================-->
195<div class="doc_subsubsection">
Misha Brukman017f2f32004-04-19 02:56:49 +0000[diff] [blame]196<a name="bugfix">In this release, the following bugs in the previous release
197were fixed:</a>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]198</div>
199
200<p>Bugs in the LLVM Core:</p>
Chris Lattnere7525b52003-10-07 21:38:31 +0000[diff] [blame]201
202<ol>
John Criswell6956afa2004-05-06 22:23:24 +0000[diff] [blame]203<li><a href="http://llvm.cs.uiuc.edu/PR330">[vmcore] Linker causes erroneous
204asssertion</a></li>
Misha Brukman017f2f32004-04-19 02:56:49 +0000[diff] [blame]205<li><a href="http://llvm.cs.uiuc.edu/PR306">[loopsimplify] Loop simplify
206incorrectly updates dominator information</a></li>
207<li><a href="http://llvm.cs.uiuc.edu/PR310">[tailduplicate] DemoteRegToStack
208breaks SSA form</a></li>
209<li><a href="http://llvm.cs.uiuc.edu/PR313">[X86] JIT miscompiles unsigned short
210to floating point cast</a></li>
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]211<li><a href="http://llvm.cs.uiuc.edu/PR332">[adce] Crash handling unreachable
212code that unwinds</a></li>
213<li><a href="http://llvm.cs.uiuc.edu/PR333">[sparc] LLC can't emit 2 functions
214of the same name, both having constant pools</a></li>
215<li><a href="http://llvm.cs.uiuc.edu/PR337">[livevar] Live variables missed
216physical register use of aliased definition</a></li>
Chris Lattner8f7cf272004-05-21 16:48:20 +0000[diff] [blame]217<li><a href="http://llvm.cs.uiuc.edu/PR340">Verifier misses malformed switch instruction</a></li>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]218</ol>
219
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]220<p>Bugs in the C/C++ front-end:</p>
221
222<ol>
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]223<li><a href="http://llvm.cs.uiuc.edu/PR326">[llvmgcc] Crash on use of undeclared
224enum type</a></li>
225<li><a href="http://llvm.cs.uiuc.edu/PR298">[llvmgcc] Variable length array
226indexing miscompiled</a></li>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]227</ol>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]228
Reid Spencer3e58f582004-05-23 17:23:13 +0000[diff] [blame]229
230<!--=========================================================================-->
231<div class="doc_subsubsection">
232<a name="misc">This release includes the following miscellaneous
233improvements:</a>
Chris Lattner23257062004-05-23 20:42:08 +0000[diff] [blame^]234</div>
Reid Spencer3e58f582004-05-23 17:23:13 +0000[diff] [blame]235
236<p>Documentation Improvements</p>
237<ol>
238<li><a href="BytecodeFormat.html">Documentation of the LLVM Bytecode file format
239was added.</a></li>
240<li>All documentation was brought up to HTML 4.01 (Strict) level.</li>
241</ol>
Reid Spencer3e58f582004-05-23 17:23:13 +0000[diff] [blame]242
243
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]244<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]245<div class="doc_section">
246 <a name="portability">Portability and Supported Platforms</a>
247</div>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]248<!-- *********************************************************************** -->
249
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]250<div class="doc_text">
251
Brian Gaekee3e557e2004-05-09 05:28:35 +0000[diff] [blame]252<p>LLVM has been extensively tested on Intel and AMD machines running Red Hat
253Linux. It has also been tested under FreeBSD, and on Sun UltraSPARC
254workstations running Solaris 8. Additionally, LLVM works on Mac OS X 10.3 and
255above, but only with the C backend and interpreter; no native machine-code
256generator for the PowerPC is available yet.</p>
257
258<p>The core LLVM infrastructure uses
259<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
260to the machine and operating system on which it is built. However, minor
261porting may be required to get LLVM to work on new platforms. We welcome your
262portability patches and reports of successful builds or error messages.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]263
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]264</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]265
Brian Gaeke86a6c752004-04-20 18:18:46 +0000[diff] [blame]266<!--=========================================================================-->
267<div class="doc_subsection">
268In this release, the following portability problems were fixed:
269</div>
270
271<ol>
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]272<li><a href="http://llvm.cs.uiuc.edu/PR304">warnings compiling Stacker compiler
273on Mac OS X</a></li>
274<li><a href="http://llvm.cs.uiuc.edu/PR308">Archive file reader doesn't
275understand abbreviated names in headers</a></li>
Brian Gaeke86a6c752004-04-20 18:18:46 +0000[diff] [blame]276</ol>
277
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]278<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]279<div class="doc_section">
280 <a name="knownproblems">Known Problems</a>
281</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]282<!-- *********************************************************************** -->
283
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]284<div class="doc_text">
285
286<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]287component. As new problems are discovered, they will be added to these
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]288sections. If you run into a problem, please check the <a
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]289href="http://llvm.cs.uiuc.edu/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]290there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]291
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]292</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]293
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]294<!-- ======================================================================= -->
295<div class="doc_subsection">
296 <a name="experimental">Experimental features included with this release</a>
297</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]298
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]299<div class="doc_text">
300
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]301<p>The following components of this LLVM release are either untested, known to
302be broken or unreliable, or are in early development. These components should
303not be relied on, and bugs should not be filed against them, but they may be
304useful to some people. In particular, if you would like to work on one of these
305components, please contact us on the llvmdev list.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]306
307<ul>
308<li>The following passes are incomplete or buggy: <tt>-pgmdep, -memdep,
309 -ipmodref, -sortstructs, -swapstructs, -cee</tt></li>
310
311<li>The <tt>-pre</tt> pass is incomplete (there are cases it doesn't handle that
312 it should) and not thoroughly tested.</li>
313<li>The <tt>llvm-ar</tt> tool is incomplete and probably buggy.</li>
314<li>The <tt>llvm-db</tt> tool is in a very early stage of development.</li>
315</ul>
316
317</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]318
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]319<!-- ======================================================================= -->
320<div class="doc_subsection">
321 <a name="core">Known problems with the LLVM Core</a>
322</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]323
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]324<div class="doc_text">
325
326<ul>
327
328<li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not
329work.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]330
331<li>The JIT does not use mutexes to protect its internal data structures. As
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]332such, execution of a threaded program could cause these data structures to be
333corrupted.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]334
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]335<li>It is not possible to <tt>dlopen</tt> an LLVM bytecode file in the JIT.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]336
Chris Lattnera623e482003-10-20 19:05:03 +0000[diff] [blame]337<li>Linking in static archive files (.a files) is very slow (there is no symbol
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]338table in the archive).</li>
Chris Lattnerc679fbb2003-11-04 20:06:53 +0000[diff] [blame]339
Misha Brukman017f2f32004-04-19 02:56:49 +0000[diff] [blame]340<li>The gccld program <a href="http://llvm.cs.uiuc.edu/PR139">does not link
341objects/archives in the order specified on the command line.</a></li>
Chris Lattneraebc66a2004-02-15 23:09:07 +0000[diff] [blame]342
343<li><a href="http://llvm.cs.uiuc.edu/PR240">The lower-invoke pass does not mark
John Criswell5d6345a2004-03-12 21:29:42 +0000[diff] [blame]344values live across a setjmp as volatile</a>. This missing feature only affects
Chris Lattneraebc66a2004-02-15 23:09:07 +0000[diff] [blame]345targets whose setjmp/longjmp libraries do not save and restore the entire
346register file.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]347</ul>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]348</div>
349
350<!-- ======================================================================= -->
351<div class="doc_subsection">
352 <a name="c-fe">Known problems with the C front-end</a>
353</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000[diff] [blame]354
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]355<!-- _______________________________________________________________________ -->
Chris Lattner5a8a7282003-12-14 05:03:43 +0000[diff] [blame]356<div class="doc_subsubsection">Bugs</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]357
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]358<div class="doc_text">
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]359<ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]360<li>C99 Variable sized arrays do not release stack memory when they go out of
361 scope. Thus, the following program may run out of stack space:
362<pre>
363 for (i = 0; i != 1000000; ++i) {
364 int X[n];
365 foo(X);
366 }
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]367</pre></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]368
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]369<li>Initialization of global union variables can only be done <a
370href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=162">with the largest union
371member</a>.</li>
Chris Lattner1ab58dd2004-03-16 21:39:04 +0000[diff] [blame]372
Misha Brukman017f2f32004-04-19 02:56:49 +0000[diff] [blame]373<li><a href="http://llvm.cs.uiuc.edu/PR244">[llvm-gcc] Error when an implicitly
374external function is re-declared as static</a></li>
Chris Lattner1ab58dd2004-03-16 21:39:04 +0000[diff] [blame]375
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]376</ul>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]377</div>
378
379<!-- _______________________________________________________________________ -->
380<div class="doc_subsubsection">
381 Notes
382</div>
383
384<div class="doc_text">
385
386<ul>
387
388<li>Inline assembly is not yet supported.</li>
Chris Lattnerd2a74272003-10-27 18:30:37 +0000[diff] [blame]389
390<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]391support for floating point data types of any size other than 32 and 64
392bits.</li>
393
394<li>The following Unix system functionality has not been tested and may not
395work:
Misha Brukman7cb4e382003-11-22 01:00:11 +0000[diff] [blame]396 <ol>
397 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
398 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
399 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
400 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
401 - These functions have not been tested.
402 </ol></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]403
404<li>Although many GCC extensions are supported, some are not. In particular,
405 the following extensions are known to <b>not be</b> supported:
406 <ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]407 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]408 <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>
409 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
410 <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 Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]411 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]412 <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>
413 <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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]414 <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>
415 <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>
416 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables.</li>
417 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
Misha Brukman7cb4e382003-11-22 01:00:11 +0000[diff] [blame]418 </ol>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]419
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]420 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]421 attribute means that the LLVM compiler ignores the presence of the attribute,
422 but the code should still work. An unsupported attribute is one which is
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]423 ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]424 the program.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]425
426 <ol>
427 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
428 Arrays whose length is computed at run time.<br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]429 Supported, but allocated stack space is not freed until the function returns (noted above).</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]430
431 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]432
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]433 Declaring that functions have no side effects or that they can never
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]434 return.<br>
435
436 <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
437 <tt>constructor</tt>, <tt>destructor</tt>, <tt>unused</tt>,
438 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
439
440 <b>Ignored:</b> <tt>noreturn</tt>, <tt>noinline</tt>,
441 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
442 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
443
444 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>,
445 <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
446 <tt>fastcall</tt>, all other target specific attributes</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]447
448 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
449 Specifying attributes of variables.<br>
450 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
451 <tt>deprecated</tt>, <tt>transparent_union</tt>,
452 <tt>unused</tt>, <tt>weak</tt><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]453
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]454 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
455 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
456 <tt>vector_size</tt>, <tt>dllimport</tt>,
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]457 <tt>dllexport</tt>, all target specific attributes.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]458
Misha Brukman8395d732003-12-12 04:37:31 +0000[diff] [blame]459 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.<br>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]460 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukman8395d732003-12-12 04:37:31 +0000[diff] [blame]461 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]462
463 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
464 all target specific attributes.</li>
465
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]466 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
467 Other built-in functions.<br>
468 We support all builtins which have a C language equivalent (e.g.,
469 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
470 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]471 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt> (ignored).</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]472
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]473 </ol>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]474
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]475 <p>The following extensions <b>are</b> known to be supported:</p>
476
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]477 <ol>
Chris Lattnerd3dc8502004-03-16 08:54:07 +0000[diff] [blame]478 <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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]479 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
480 <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>
481 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
482 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
483 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
484 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
485 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
486 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
487 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
488 <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>
489 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
490 <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 Brukman8395d732003-12-12 04:37:31 +0000[diff] [blame]491 <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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]492 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]493 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
494or arrays as values.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]495 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.</li>
Misha Brukman8395d732003-12-12 04:37:31 +0000[diff] [blame]496 <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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]497 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
498 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
499 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
500 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized.</li>
501 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
502 <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>
503 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
504 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
505 <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>
506 <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>
507 <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 Lattner3646dad2004-02-14 04:08:29 +0000[diff] [blame]508 <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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]509 <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>
510 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.</li>
Misha Brukman7cb4e382003-11-22 01:00:11 +0000[diff] [blame]511 </ol></li>
512
513</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]514
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]515<p>If you run into GCC extensions which have not been included in any of these
516lists, please let us know (also including whether or not they work).</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]517
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]518</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]519
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]520<!-- ======================================================================= -->
521<div class="doc_subsection">
522 <a name="c++-fe">Known problems with the C++ front-end</a>
523</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]524
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]525<div class="doc_text">
526
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]527<p>For this release, the C++ front-end is considered to be fully functional but
Chris Lattnere76e9ab2003-12-12 04:25:33 +0000[diff] [blame]528has not been tested as thoroughly as the C front-end. It has been tested and
529works for a number of non-trivial programs, but there may be lurking bugs.
530Please report any bugs or problems.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]531
532</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]533
534<!-- _______________________________________________________________________ -->
Chris Lattner141ebb62004-02-14 04:12:41 +0000[diff] [blame]535<div class="doc_subsubsection">Bugs</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]536
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]537<div class="doc_text">
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]538
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]539<ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]540<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]541 front-end</a>.</li>
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]542</ul>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]543</div>
544
545<!-- _______________________________________________________________________ -->
546<div class="doc_subsubsection">
547 Notes
548</div>
549
550<div class="doc_text">
551
552<ul>
Chris Lattnerd2a74272003-10-27 18:30:37 +0000[diff] [blame]553
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]554<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
555parser is significantly more standards compliant (and picky) than prior GCC
556versions. For more information, see the C++ section of the <a
Chris Lattnere76e9ab2003-12-12 04:25:33 +0000[diff] [blame]557href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]558
559<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]560 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]561 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]562 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]563 better than most compilers).</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]564
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]565<li>The LLVM C++ front-end follows the <a
566 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
567 This document, which is not Itanium specific, specifies a standard for name
568 mangling, class layout, v-table layout, RTTI formats, and other C++
569 representation issues. Because we use this API, code generated by the LLVM
570 compilers should be binary compatible with machine code generated by other
571 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
572 <i>However</i>, the exception handling mechanism used by LLVM is very
573 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]574 interact correctly</b>. </li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]575
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]576</ul>
Chris Lattner46ecf612003-10-07 22:14:37 +0000[diff] [blame]577
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]578</div>
579
580<!-- ======================================================================= -->
581<div class="doc_subsection">
582 <a name="x86-be">Known problems with the X86 back-end</a>
583</div>
584
585<div class="doc_text">
586
587<ul>
Chris Lattnerc5b7b242004-02-08 22:23:33 +0000[diff] [blame]588<li>None so far.
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]589</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]590
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]591</div>
592
593<!-- ======================================================================= -->
594<div class="doc_subsection">
595 <a name="sparc-be">Known problems with the Sparc back-end</a>
596</div>
597
598<div class="doc_text">
599
600<ul>
Chris Lattner9e0b81c2004-03-19 19:22:28 +0000[diff] [blame]601<li>There are several programs in the LLVM testsuite that the Sparc code generator is known to miscompile.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]602</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]603
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]604</div>
605
606<!-- ======================================================================= -->
607<div class="doc_subsection">
608 <a name="c-be">Known problems with the C back-end</a>
609</div>
610
611<div class="doc_text">
612
613<ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]614
615<li>The C back-end produces code that violates the ANSI C Type-Based Alias
616Analysis rules. As such, special options may be necessary to compile the code
617(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]618problem probably cannot be fixed.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]619
Chris Lattnera623e482003-10-20 19:05:03 +0000[diff] [blame]620<li><a href="http://llvm.cs.uiuc.edu/PR33">Initializers for global variables</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]621cannot include special floating point numbers like Not-A-Number or
622Infinity.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]623
Chris Lattnerc679fbb2003-11-04 20:06:53 +0000[diff] [blame]624<li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
Chris Lattnerb28c3282003-10-24 04:03:19 +0000[diff] [blame]625supported</a>. This should not affect LLVM produced by the C or C++
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]626frontends.</li>
Chris Lattnerb28c3282003-10-24 04:03:19 +0000[diff] [blame]627
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]628</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]629
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]630</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]631
632<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]633<div class="doc_section">
634 <a name="additionalinfo">Additional Information</a>
635</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]636<!-- *********************************************************************** -->
637
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]638<div class="doc_text">
639
640<p>A wide variety of additional information is available on the LLVM web page,
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]641including mailing lists and publications describing algorithms and components
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]642implemented in LLVM. The web page also contains versions of the API
643documentation which is up-to-date with the CVS version of the source code. You
644can access versions of these documents specific to this release by going into
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]645the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]646
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]647<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]648us via the <a href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">mailing
649lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]650
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]651</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]652
653<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]654
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]655<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]656<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000[diff] [blame]657 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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660 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
661
Misha Brukman7cb4e382003-11-22 01:00:11 +0000[diff] [blame]662 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]663 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]664</address>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]665
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]666</body>
667</html>