Gitiles
Code Review Sign In
gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 3b904eb3518603161e7033068f74cdeeffd670a1 / . / docs / ReleaseNotes.html
blob: c7640ec9925a98566681169ba89bd0008371a261 [file] [log] [blame]
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
3<html>
4<head>
5 <link rel="stylesheet" href="llvm.css" type="text/css">
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]6 <title>LLVM 1.2 Release Notes</title>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]7</head>
8<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]9
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]10<div class="doc_title">
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]11 LLVM 1.2 Release Notes
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]12</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]13
14<ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]15 <li><a href="#intro">Introduction</a></li>
16 <li><a href="#whatsnew">What's New?</a></li>
17 <li><a href="#portability">Portability and Supported Platforms</a></li>
18 <li><a href="#install-instructions">Installation Instructions</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]19 <li><a href="#knownproblems">Known Problems</a>
20 <ul>
Chris Lattner79c3fe12003-10-02 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 Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]27 </ul></li>
28 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]29</ol>
30
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]31<div class="doc_text">
John Criswelld000e1d2003-12-18 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 Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]33</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]34
35<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]36<div class="doc_section">
37 <a name="intro">Introduction</a>
38</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]39<!-- *********************************************************************** -->
40
Misha Brukman500bc302003-11-22 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 Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]44infrastructure, release 1.2. Here we describe the status of LLVM, including any
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]45known problems and bug fixes from the previous release. The most up-to-date
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]46version of this document can be found on the <a
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]47href="http://llvm.cs.uiuc.edu/releases/1.2/">LLVM 1.2 web site</a>. If you are
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]48not reading this on the LLVM web pages, you should probably go there because
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]49this document may be updated after the release.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]50
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]51<p>For more information about LLVM, including information about potentially more
Chris Lattner47ad72c2003-10-07 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 Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]55list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]56
Chris Lattner9e848092003-12-12 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 Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]60href="http://llvm.cs.uiuc.edu/releases/">releases page</a>.</p>
61
62</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]63
64<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]65<div class="doc_section">
66 <a name="whatsnew">What's New?</a>
67</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]68<!-- *********************************************************************** -->
69
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]70<div class="doc_text">
71
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]72<p>This is the third public release of the LLVM compiler infrastructure.
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]73</p>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]74
Chris Lattner1124e2c2003-12-12 21:33:08 +0000[diff] [blame]75<p>At this time, LLVM is known to correctly compile and run all non-unwinding C
76&amp; C++ SPEC CPU2000 benchmarks, the Olden benchmarks, and the Ptrdist
77benchmarks. It has also been used to compile <b>many</b> other programs. LLVM
78now also works with a broad variety of C++ programs, though it has still
79received much less testing than the C front-end.
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]80</p>
81
82<p>
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]83The LLVM native code generators are very stable but do not currently support
Chris Lattner1124e2c2003-12-12 21:33:08 +0000[diff] [blame]84unwinding (exception throwing or <tt>longjmp</tt>ing), which prevent them from
85working with programs like the <tt>253.perlbmk</tt> in SPEC CPU2000. The C
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]86backend and the rest of LLVM supports these programs, so you can
Chris Lattner1124e2c2003-12-12 21:33:08 +0000[diff] [blame]87still use LLVM with them. Support for unwinding will be added in a future
88release.
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]89</p>
90
91
92<!--=========================================================================-->
93<div class="doc_subsubsection">
94This release implements the following new features:
95</div>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]96
97<ol>
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]98<li></li>
99<li></li>
Chris Lattner55ee0312003-11-19 22:05:38 +0000[diff] [blame]100</ol>
Chris Lattner0ef19062003-11-08 04:28:55 +0000[diff] [blame]101
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]102
103<!--=========================================================================-->
104<div class="doc_subsubsection">
105In this release, the following missing features were implemented:
106</div>
Chris Lattner0ef19062003-11-08 04:28:55 +0000[diff] [blame]107
108<ol>
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]109<li></li>
110<li></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]111</ol>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]112
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]113
114<!--=========================================================================-->
115<div class="doc_subsubsection">
Chris Lattnere29ac162003-12-20 03:42:11 +0000[diff] [blame]116In this release, the following Quality of Implementation issues were fixed:
117</div>
118
119<ol>
120
121<li><a href="http://llvm.cs.uiuc.edu/PR135">JIT should lazily initialize global variables</a></li>
Chris Lattneref56a192003-12-20 10:29:02 +0000[diff] [blame]122<li><a href="http://llvm.cs.uiuc.edu/PR192">[X86] X86 Backend never releases memory for machine code structures</a></li>
Chris Lattner71f0a822003-12-23 23:50:31 +0000[diff] [blame]123<li><a href="http://llvm.cs.uiuc.edu/PR196">[vmcore] OpaqueType objects memory leak</a></li>
Chris Lattner1abc87e2004-01-08 17:20:50 +0000[diff] [blame]124<li><a href="http://llvm.cs.uiuc.edu/PR182">[llvmgcc] C front-end does not compile "extern inline" into linkonce</a></li>
Chris Lattner23632f12004-01-15 17:59:29 +0000[diff] [blame]125<li><a href="http://llvm.cs.uiuc.edu/PR73">Bytecode format inconsistent</a></li>
Chris Lattnere29ac162003-12-20 03:42:11 +0000[diff] [blame]126</ol>
127
128<!--=========================================================================-->
129<div class="doc_subsubsection">
Brian Gaeke6b31beb2004-01-16 21:55:04 +0000[diff] [blame]130In this release, the following build problems were fixed:
131</div>
132
133<ol>
134<li><a href="http://llvm.cs.uiuc.edu/PR210">[build] Makefiles break if C frontend target string has unexpected value</a></li>
John Criswell6b153402004-01-26 21:03:54 +0000[diff] [blame]135<li><a href="http://llvm.cs.uiuc.edu/PR214">[build] hard-wired assumption that shared-library extension is ".so"</a></li>
Brian Gaeke6b31beb2004-01-16 21:55:04 +0000[diff] [blame]136</ol>
137
138<!--=========================================================================-->
139<div class="doc_subsubsection">
Chris Lattnere29ac162003-12-20 03:42:11 +0000[diff] [blame]140In this release, the following Code Quality issues were fixed:
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]141</div>
Chris Lattner89ca2b82003-10-27 17:06:39 +0000[diff] [blame]142
143<ol>
Chris Lattner9e259062003-12-19 06:31:56 +0000[diff] [blame]144<li><a href="http://llvm.cs.uiuc.edu/PR187">[loopsimplify] Many pointless phi nodes are created</a></li>
Chris Lattner02babb82004-02-02 19:40:06 +0000[diff] [blame]145<li>The X86 backend didn't generate <tt>fchs</tt> to negate floating point numbers</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]146</ol>
Chris Lattner89ca2b82003-10-27 17:06:39 +0000[diff] [blame]147
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]148
149<!--=========================================================================-->
150<div class="doc_subsubsection">
151In this release, the following bugs in the previous release were fixed:
152</div>
153
154<p>Bugs in the LLVM Core:</p>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]155
156<ol>
Misha Brukmanad643852003-12-15 22:48:12 +0000[diff] [blame]157<li><a href="http://llvm.cs.uiuc.edu/PR179">[licm] LICM promotes volatile memory
158locations to registers</a></li>
Chris Lattner5b7142a2003-12-18 08:16:25 +0000[diff] [blame]159<li><a href="http://llvm.cs.uiuc.edu/PR191">[licm] Memory read after free causes
160infrequent crash</a></li>
Chris Lattner5de946f2003-12-22 04:06:24 +0000[diff] [blame]161<li><a href="http://llvm.cs.uiuc.edu/PR194">[indvars] Induction variable
162canonicalization always makes 32-bit indvars</a></li>
Chris Lattner0cbdd972003-12-22 23:56:37 +0000[diff] [blame]163<li><a href="http://llvm.cs.uiuc.edu/PR193">[constantmerge] Merging globals can
164cause use of invalid pointers!</a></li>
Chris Lattnerae3664b2004-01-20 19:16:50 +0000[diff] [blame]165<li><a href="http://llvm.cs.uiuc.edu/PR212">[bcreader] Bytecode reader misreads 'long -9223372036854775808'!</a></li>
Chris Lattnerc8a35812004-02-01 22:52:12 +0000[diff] [blame]166<li><a href="http://llvm.cs.uiuc.edu/PR218">VMCore mishandles double -0.0</a></li>
Chris Lattner02babb82004-02-02 19:40:06 +0000[diff] [blame]167<li><a href="http://llvm.cs.uiuc.edu/PR219">[X86] X86 backend code generates -0.0 as +0.0</a></li>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]168</ol>
169
170
171<p>Bugs in the C/C++ front-end:</p>
172
173<ol>
Misha Brukmanad643852003-12-15 22:48:12 +0000[diff] [blame]174<li><a href="http://llvm.cs.uiuc.edu/PR186">Need weak linkage on memory
175management functions in libc runtime to allow them to be overriden</a></li>
Chris Lattner1abc87e2004-01-08 17:20:50 +0000[diff] [blame]176<li><a href="http://llvm.cs.uiuc.edu/PR202">[llvm-gcc] asserts when an extern inline function is redefined</a></li>
Chris Lattnerc43f91f2004-01-12 05:15:04 +0000[diff] [blame]177<li><a href="http://llvm.cs.uiuc.edu/PR204">[llvmg++] Dynamically initialized constants cannot be marked 'constant'</a></li>
Chris Lattner55d14de2004-02-02 17:48:56 +0000[diff] [blame]178<li><a href="http://llvm.cs.uiuc.edu/PR216">[llvmgcc] floating-point unary minus is incorrect for +0.0</a></li>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]179</ol>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]180
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]181</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]182
183<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]184<div class="doc_section">
185 <a name="portability">Portability and Supported Platforms</a>
186</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]187<!-- *********************************************************************** -->
188
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]189<div class="doc_text">
190
191<p>LLVM has been extensively tested on Intel and AMD machines running Red
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]192Hat Linux and FreeBSD. It has also been tested on Sun UltraSPARC workstations running Solaris 8.
John Criswellbb1bad52003-12-12 19:54:20 +0000[diff] [blame]193Additionally,
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]194LLVM works on Mac OS X 10.3 and above, but only with the C backend or
Chris Lattner9e848092003-12-12 04:25:33 +0000[diff] [blame]195interpreter (no native backend for the PowerPC is available yet).
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]196The core LLVM infrastructure uses "autoconf" for portability, so hopefully we
Chris Lattner3e2959e2003-11-08 05:22:09 +0000[diff] [blame]197work on more platforms than that. However, it is likely that we
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]198missed something and that minor porting is required to get LLVM to work on
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]199new platforms. We welcome portability patches and error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]200
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]201</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]202
203<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]204<div class="doc_section">
205 <a name="knownproblems">Known Problems</a>
206</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]207<!-- *********************************************************************** -->
208
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]209<div class="doc_text">
210
211<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]212component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]213sections. If you run into a problem, please check the <a
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]214href="http://llvm.cs.uiuc.edu/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]215there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]216
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]217</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]218
219<!-- _______________________________________________________________________ -->
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]220<!--
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]221</ul><h4><a name="portability"><hr size=0>Portability Problems</h4><ul>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]222-->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]223
224
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]225<!-- ======================================================================= -->
226<div class="doc_subsection">
227 <a name="core">Known problems with the LLVM Core</a>
228</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]229
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]230<div class="doc_text">
231
232<ul>
233
234<li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not
235work.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]236
237<li>The JIT does not use mutexes to protect its internal data structures. As
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]238such, execution of a threaded program could cause these data structures to be
239corrupted.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]240
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]241<li>It is not possible to <tt>dlopen</tt> an LLVM bytecode file in the JIT.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]242
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]243<li>Linking in static archive files (.a files) is very slow (there is no symbol
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]244table in the archive).</li>
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]245
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]246<li><a href="http://llvm.cs.uiuc.edu/PR82">LLVM cannot handle structures with
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]247more than 256 elements</a>.</li>
248
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]249<li>
250The gccld program
251<a href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=139">
252does not link objects/archives in the order specified on the command line.
253</a>
254</li>
255
256<li>
257<a href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=174">
258Tail duplication does not update SSA form correctly.
259</a>
260</li>
Chris Lattner655c8d62004-01-18 20:13:43 +0000[diff] [blame]261
262<li><a href="http://llvm.cs.uiuc.edu/PR16">[lowerinvoke] The -lowerinvoke pass
263does not insert calls to setjmp/longjmp</a>.</li>
264
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]265</ul>
266
267</div>
268
269<!-- ======================================================================= -->
270<div class="doc_subsection">
271 <a name="c-fe">Known problems with the C front-end</a>
272</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]273
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]274<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]275<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]276
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]277<div class="doc_text">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]278<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]279<li>C99 Variable sized arrays do not release stack memory when they go out of
280 scope. Thus, the following program may run out of stack space:
281<pre>
282 for (i = 0; i != 1000000; ++i) {
283 int X[n];
284 foo(X);
285 }
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]286</pre></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]287
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]288<li>
289Initialization of global union variables can only be done
290<a href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=162">with the largest
291union member</a>.
292</li>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]293
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]294<li>
295<a href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=182">
296Functions marked "extern inline" are not compiled into LLVM with linkonce
297linkage.
298</a>
299</li>
300
301
302<li>
303The memory management functions in the libc runtime
304<a href="http://llvm.cs.uiuc.edu/PR186">need weak linkage so that they can be
305overridden.
306</a>
307</li>
308</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]309</div>
310
311<!-- _______________________________________________________________________ -->
312<div class="doc_subsubsection">
313 Notes
314</div>
315
316<div class="doc_text">
317
318<ul>
319
320<li>Inline assembly is not yet supported.</li>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]321
322<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]323support for floating point data types of any size other than 32 and 64
324bits.</li>
325
326<li>The following Unix system functionality has not been tested and may not
327work:
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]328 <ol>
329 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
330 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
331 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
332 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
333 - These functions have not been tested.
334 </ol></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]335
336<li>Although many GCC extensions are supported, some are not. In particular,
337 the following extensions are known to <b>not be</b> supported:
338 <ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]339 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]340 <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]341 <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>
342 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
343 <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]344 <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]345 <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>
346 <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>
347 <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>
348 <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>
349 <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>
350 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables.</li>
351 <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]352 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]353
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]354 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]355 attribute means that the LLVM compiler ignores the presence of the attribute,
356 but the code should still work. An unsupported attribute is one which is
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]357 ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]358 the program.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]359
360 <ol>
361 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
362 Arrays whose length is computed at run time.<br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]363 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]364
365 <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]366
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]367 Declaring that functions have no side effects or that they can never
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]368 return.<br>
369
370 <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
371 <tt>constructor</tt>, <tt>destructor</tt>, <tt>unused</tt>,
372 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
373
374 <b>Ignored:</b> <tt>noreturn</tt>, <tt>noinline</tt>,
375 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
376 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
377
378 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>,
379 <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
380 <tt>fastcall</tt>, all other target specific attributes</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]381
382 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
383 Specifying attributes of variables.<br>
384 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
385 <tt>deprecated</tt>, <tt>transparent_union</tt>,
386 <tt>unused</tt>, <tt>weak</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]387
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]388 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
389 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
390 <tt>vector_size</tt>, <tt>dllimport</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]391 <tt>dllexport</tt>, all target specific attributes.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]392
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]393 <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]394 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]395 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]396
397 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
398 all target specific attributes.</li>
399
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]400 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
401 Other built-in functions.<br>
402 We support all builtins which have a C language equivalent (e.g.,
403 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
404 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]405 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt> (ignored).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]406
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]407 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]408
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]409 <p>The following extensions <b>are</b> known to be supported:</p>
410
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]411 <ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]412 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
413 <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>
414 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
415 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
416 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
417 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
418 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
419 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
420 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
421 <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>
422 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
423 <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]424 <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]425 <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]426 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
427or arrays as values.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]428 <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]429 <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]430 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
431 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
432 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
433 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized.</li>
434 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
435 <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>
436 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
437 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
438 <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>
439 <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>
440 <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>
441 <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>
442 <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]443 </ol></li>
444
445</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]446
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]447<p>If you run into GCC extensions which have not been included in any of these
448lists, please let us know (also including whether or not they work).</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]449
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]450</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]451
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]452<!-- ======================================================================= -->
453<div class="doc_subsection">
454 <a name="c++-fe">Known problems with the C++ front-end</a>
455</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]456
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]457<div class="doc_text">
458
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]459<p>For this release, the C++ front-end is considered to be fully functional but
Chris Lattner9e848092003-12-12 04:25:33 +0000[diff] [blame]460has not been tested as thoroughly as the C front-end. It has been tested and
461works for a number of non-trivial programs, but there may be lurking bugs.
462Please report any bugs or problems.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]463
464</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]465
466<!-- _______________________________________________________________________ -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]467<div class="doc_subsubsection">
468 Bugs
469</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]470
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]471<div class="doc_text">
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]472
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]473<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]474<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]475 front-end</a>.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]476
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]477<li>
478<a href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=137">
479Code is generated for empty classes.
480</a>
481</li>
482</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]483</div>
484
485<!-- _______________________________________________________________________ -->
486<div class="doc_subsubsection">
487 Notes
488</div>
489
490<div class="doc_text">
491
492<ul>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]493
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]494<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
495parser is significantly more standards compliant (and picky) than prior GCC
496versions. For more information, see the C++ section of the <a
Chris Lattner9e848092003-12-12 04:25:33 +0000[diff] [blame]497href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]498
499<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]500 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]501 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]502 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]503 better than most compilers).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]504
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]505<li>The LLVM C++ front-end follows the <a
506 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
507 This document, which is not Itanium specific, specifies a standard for name
508 mangling, class layout, v-table layout, RTTI formats, and other C++
509 representation issues. Because we use this API, code generated by the LLVM
510 compilers should be binary compatible with machine code generated by other
511 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
512 <i>However</i>, the exception handling mechanism used by LLVM is very
513 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]514 interact correctly</b>. </li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]515
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]516</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]517
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]518</div>
519
520<!-- ======================================================================= -->
521<div class="doc_subsection">
522 <a name="x86-be">Known problems with the X86 back-end</a>
523</div>
524
525<div class="doc_text">
526
527<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]528
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]529<li>The X86 code generator <a
Chris Lattner0d4379a2003-10-08 06:01:38 +0000[diff] [blame]530href="http://llvm.cs.uiuc.edu/PR16">does not currently
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]531support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]532or calls the C <tt>longjmp</tt> function will abort.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]533
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]534</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]535
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]536</div>
537
538<!-- ======================================================================= -->
539<div class="doc_subsection">
540 <a name="sparc-be">Known problems with the Sparc back-end</a>
541</div>
542
543<div class="doc_text">
544
545<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]546
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]547<li>The Sparc code generator <a
Chris Lattner655c8d62004-01-18 20:13:43 +0000[diff] [blame]548href="http://llvm.cs.uiuc.edu/PR16">does not currently
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]549support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]550or calls the C <tt>longjmp</tt> function will abort.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]551
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]552<li>
553<a href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=167">
554The llc program can crash on legal code.
555</a>
556</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]557</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]558
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]559</div>
560
561<!-- ======================================================================= -->
562<div class="doc_subsection">
563 <a name="c-be">Known problems with the C back-end</a>
564</div>
565
566<div class="doc_text">
567
568<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]569
570<li>The C back-end produces code that violates the ANSI C Type-Based Alias
571Analysis rules. As such, special options may be necessary to compile the code
572(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]573problem probably cannot be fixed.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]574
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]575<li><a href="http://llvm.cs.uiuc.edu/PR33">Initializers for global variables</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]576cannot include special floating point numbers like Not-A-Number or
577Infinity.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]578
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]579<li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]580supported</a>. This should not affect LLVM produced by the C or C++
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]581frontends.</li>
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]582
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]583</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]584
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]585</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]586
587<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]588<div class="doc_section">
589 <a name="additionalinfo">Additional Information</a>
590</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]591<!-- *********************************************************************** -->
592
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]593<div class="doc_text">
594
595<p>A wide variety of additional information is available on the LLVM web page,
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]596including mailing lists and publications describing algorithms and components
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]597implemented in LLVM. The web page also contains versions of the API
598documentation which is up-to-date with the CVS version of the source code. You
599can access versions of these documents specific to this release by going into
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]600the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]601
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]602<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]603us via the <a href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">mailing
604lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]605
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]606</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]607
608<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]609
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]610<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]611<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]612 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]613 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
614 <a href="http://validator.w3.org/check/referer"><img
615 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
616
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]617 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]618 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]619</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]620
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]621</body>
622</html>