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6 <title>LLVM 1.1 Release Notes</title>
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8<body>
Chris Lattner3d482502003-10-02 04:57:28 +00009
Misha Brukman80731b92003-11-22 00:38:41 +000010<div class="doc_title">
11 LLVM 1.1 Release Notes
12</div>
Chris Lattner3d482502003-10-02 04:57:28 +000013
14<ol>
Misha Brukman80731b92003-11-22 00:38:41 +000015 <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 Lattner3d482502003-10-02 04:57:28 +000019 <li><a href="#knownproblems">Known Problems</a>
20 <ul>
Chris Lattner62495762003-10-02 16:38:05 +000021<!-- <li><a href="#portabilityprobs">Portability Problems</a> -->
Chris Lattner3d482502003-10-02 04:57:28 +000022 <li><a href="#core">Known problems with the LLVM Core</a>
23 <li><a href="#c-fe">Known problems with the C Front-end</a>
24 <li><a href="#c++-fe">Known problems with the C++ Front-end</a>
25 <li><a href="#x86-be">Known problems with the X86 Back-end</a>
26 <li><a href="#sparc-be">Known problems with the Sparc Back-end</a>
27 <li><a href="#c-be">Known problems with the C back-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +000028 </ul></li>
29 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +000030</ol>
31
Misha Brukman7cb4e382003-11-22 01:00:11 +000032<div class="doc_text">
Misha Brukman80731b92003-11-22 00:38:41 +000033 <p><b>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></b><p>
34</div>
Chris Lattner3d482502003-10-02 04:57:28 +000035
36<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +000037<div class="doc_section">
38 <a name="intro">Introduction</a>
39</div>
Chris Lattner3d482502003-10-02 04:57:28 +000040<!-- *********************************************************************** -->
41
Misha Brukman80731b92003-11-22 00:38:41 +000042<div class="doc_text">
43
44<p>This document contains the release notes for the LLVM compiler
45infrastructure, release 1.1. Here we describe the status of LLVM, including any
46known problems, and bug fixes from the previous release. The most up-to-date
47version of this document can be found on the <a
Chris Lattner7c4bd1d2003-10-27 01:31:14 +000048href="http://llvm.cs.uiuc.edu/releases/1.1/">LLVM 1.1 web site</a>. If you are
Chris Lattnere7525b52003-10-07 21:38:31 +000049not reading this on the LLVM web pages, you should probably go there, because
Misha Brukman80731b92003-11-22 00:38:41 +000050this document may be updated after the release.</p>
Chris Lattner62495762003-10-02 16:38:05 +000051
Misha Brukman80731b92003-11-22 00:38:41 +000052<p>For more information about LLVM, including information about potentially more
Chris Lattnere7525b52003-10-07 21:38:31 +000053current releases, please check out the <a href="http://llvm.cs.uiuc.edu">main
54web site</a>. If you have questions or comments, the <a
55href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman80731b92003-11-22 00:38:41 +000056list</a> is a good place to send them.</p>
Chris Lattner3d482502003-10-02 04:57:28 +000057
Chris Lattnere76e9ab2003-12-12 04:25:33 +000058<p>Note that if you are reading this file from CVS, this document applies
59to the <i>next</i> release, not the current one. To see the release notes for
60the current or previous releases, see the <a
Misha Brukman80731b92003-11-22 00:38:41 +000061href="http://llvm.cs.uiuc.edu/releases/">releases page</a>.</p>
62
63</div>
Chris Lattner3d482502003-10-02 04:57:28 +000064
65<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +000066<div class="doc_section">
67 <a name="whatsnew">What's New?</a>
68</div>
Chris Lattner3d482502003-10-02 04:57:28 +000069<!-- *********************************************************************** -->
70
Misha Brukman80731b92003-11-22 00:38:41 +000071<div class="doc_text">
72
73<p>This is the second public release of the LLVM compiler infrastructure. This
Chris Lattnerba7bd472003-12-06 20:22:41 +000074release is primarily a bugfix release, dramatically improving the C/C++
75front-end, and improving support for C++ in the LLVM core. This release also
Chris Lattnerd98fecb2003-12-06 20:24:46 +000076includes a few new features, such as a simple profiler, support for Mac OS/X,
Chris Lattnerd25f26f2003-12-12 04:45:09 +000077better interoperability with external source bases, a new example language
78front-end, and improves a few optimizations.</p>
Chris Lattnerba7bd472003-12-06 20:22:41 +000079
Chris Lattnere4151eb2003-12-11 23:31:21 +000080<p>At this time, LLVM is known to correctly compile the C &amp; C++ SPEC CPU2000
81benchmarks (X86 only), the Olden benchmarks, and the Ptrdist benchmarks along
82with <b>many</b> other programs. LLVM now also works with a broad variety of
Chris Lattnerba7bd472003-12-06 20:22:41 +000083C++ programs, though it has still received much less testing than the C
84front-end.
85</p>
86
87<p>
88Note that the Sparc and X86 backends do not currently support exception throwing
89or long jumping (including 253.perlbmk in SPEC). For these programs, you must
90use the C backend. Support for unwinding will be added in a future release.
91</p>
92
93
94<!--=========================================================================-->
95<div class="doc_subsubsection">
96This release implements the following new features:
97</div>
Chris Lattnere7525b52003-10-07 21:38:31 +000098
99<ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000100<li><a
Chris Lattner592db402003-11-19 22:05:38 +0000101href="http://mail.cs.uiuc.edu/pipermail/llvmdev/2003-November/000528.html">A new
Misha Brukman80731b92003-11-22 00:38:41 +0000102LLVM profiler, similar to gprof</a> is available</li>
Chris Lattner4491de62003-11-08 04:28:55 +0000103
Chris Lattnerba7bd472003-12-06 20:22:41 +0000104<li>LLVM and the C/C++ front-end now compile on Mac OS/X! Mac OS/X users can
Chris Lattnere76e9ab2003-12-12 04:25:33 +0000105now explore the LLVM optimizer with the C backend and interpreter. Note that
106LLVM requires GCC 3.3 on Mac OS/X.</li>
Chris Lattner4491de62003-11-08 04:28:55 +0000107
Misha Brukman80731b92003-11-22 00:38:41 +0000108<li>LLVM has been <a
Chris Lattner74a22992003-11-11 23:46:35 +0000109href="http://mail.cs.uiuc.edu/pipermail/llvmdev/2003-November/000554.html">moved
110into an 'llvm' C++ namespace</a>, for easier integration with third-party
Chris Lattnere76e9ab2003-12-12 04:25:33 +0000111code. Note that due to lack of namespace support in GDB 5.x, you will probably
112want to upgrade to GDB 6 or better to debug LLVM code.</li>
John Criswellf1387a52003-11-26 20:09:49 +0000113
114<li>
115The build system now copies Makefiles dynamically from the source tree to the
116object tree as subdirectories are built. This means that:
117 <ol>
118 <li>
119 New directories can be added to the source tree, and the build will
120 automatically pick them up (i.e. no need to re-run <tt>configure</tt>).
121 </li>
122
123 <li>
124 You will need to build LLVM from the top of the object tree once to ensure
125 that all of the Makefiles are copied into the object tree subdirectories.
126 </li>
127 </ol>
128</li>
129
Chris Lattnerd25f26f2003-12-12 04:45:09 +0000130<li>A front-end for "Stacker" (a simple Forth-like language) is now
131 <a href="http://llvm.cs.uiuc.edu/PR136">included in the main LLVM tree</a>.
132 Additionally, Reid Spencer, the author, contributed a document <a href="Stacker.html">describing his experiences writing Stacker, and the language itself</a>. This document is invaluable for others writing front-ends targetting LLVM.</li>
133
Chris Lattnere4151eb2003-12-11 23:31:21 +0000134<li>The <tt>configure</tt> script will now configure all projects placed in the
135<tt>llvm/projects</tt> directory.</li>
136
Chris Lattner88e24cf2003-12-12 04:51:00 +0000137<li>The <tt>-tailcallelim</tt> pass can now introduce "accumulator" variables
138 to transform functions in many common cases that it could not before.</li>
139
Chris Lattnere76e9ab2003-12-12 04:25:33 +0000140<li>The <tt>-licm</tt> pass can now sink instructions out the bottom of loops
141in addition to being able to hoist them out the top.</li>
142
Chris Lattnere76e9ab2003-12-12 04:25:33 +0000143<li>The <tt>-basicaa</tt> pass (the default alias analysis) has been upgraded
144to be <a href="http://llvm.cs.uiuc.edu/PR86">significantly more
145precise</a>.</li>
Chris Lattnere4151eb2003-12-11 23:31:21 +0000146
Chris Lattner4b34b352003-12-12 05:52:39 +0000147<li>LLVM 1.1 implements a simple size optimization for LLVM bytecode files.
148 This means that the 1.1 files are smaller than 1.0, but that 1.0 won't
149 read 1.1 bytecode files.</li>
Chris Lattner592db402003-11-19 22:05:38 +0000150</ol>
Chris Lattner4491de62003-11-08 04:28:55 +0000151
Chris Lattnerba7bd472003-12-06 20:22:41 +0000152
153<!--=========================================================================-->
154<div class="doc_subsubsection">
155In this release, the following missing features were implemented:
156</div>
Chris Lattner4491de62003-11-08 04:28:55 +0000157
158<ol>
159<li><a href="http://llvm.cs.uiuc.edu/PR88">The interpreter does not support
160invoke or unwind</a></li>
Misha Brukman133b35e2003-11-14 03:30:43 +0000161
162<li><a href="http://llvm.cs.uiuc.edu/PR99">Interpreter does not support the
Chris Lattner592db402003-11-19 22:05:38 +0000163<tt>vaarg</tt> instruction</a></li>
Misha Brukman133b35e2003-11-14 03:30:43 +0000164
Brian Gaekec5961312003-11-16 23:49:26 +0000165<li><a href="http://llvm.cs.uiuc.edu/PR117">llvm-nm cannot read archive
Chris Lattner592db402003-11-19 22:05:38 +0000166files</a></li>
Brian Gaekec5961312003-11-16 23:49:26 +0000167
Brian Gaeke4c563b82003-12-11 04:40:58 +0000168<li><a href="http://llvm.cs.uiuc.edu/PR146">Interpreter does not handle
169setne constant expression</a></li>
170
Misha Brukman80731b92003-11-22 00:38:41 +0000171</ol>
Chris Lattnere7525b52003-10-07 21:38:31 +0000172
Chris Lattnerba7bd472003-12-06 20:22:41 +0000173
174<!--=========================================================================-->
175<div class="doc_subsubsection">
176In this release, the following Quality of Implementation issues were
177fixed:
178</div>
Chris Lattner639579c2003-10-27 17:06:39 +0000179
180<ol>
Chris Lattner4491de62003-11-08 04:28:55 +0000181
Chris Lattnereb8b1842003-12-12 04:56:02 +0000182<li>The C++ front-end now compiles functions to
183 <a href="http://llvm.cs.uiuc.edu/PR29">use the linkonce linkage type</a>
184 more, giving the optimizer more freedom.</a></li>
Chris Lattner4491de62003-11-08 04:28:55 +0000185
Chris Lattnereb8b1842003-12-12 04:56:02 +0000186<li>The C front-end now <a href="http://llvm.cs.uiuc.edu/PR84">generates
187 type-safe code</a> in several cases that it did not before, which prevented
188 some important optimizations.</li>
Chris Lattner4491de62003-11-08 04:28:55 +0000189
Chris Lattnereb8b1842003-12-12 04:56:02 +0000190<li>The LLVM build system has been taught to catch some common configuration
191 problems that <a href="http://llvm.cs.uiuc.edu/PR96">caused it to get
192 horribly confused</a> before.</li>
Chris Lattnerb2e4d6d2003-11-16 20:25:24 +0000193
Chris Lattnereb8b1842003-12-12 04:56:02 +0000194<li>The LLVM header files are now
195 <a href="http://llvm.cs.uiuc.edu/PR114">-Wold-style-cast clean</a>.</li>
Chris Lattnerb2e4d6d2003-11-16 20:25:24 +0000196
Chris Lattner592db402003-11-19 22:05:38 +0000197<li>The LLVM bytecode reader has been <a
198href="http://llvm.cs.uiuc.edu/PR127">sped up a lot</a> (up to 4x in some
199cases).</li>
200
Chris Lattnere76e9ab2003-12-12 04:25:33 +0000201<li>In C++, methods and functions in anonymous namespaces <a href="http://llvm.cs.uiuc.edu/PR85">now get internal linkage</a>.</li>
Chris Lattner3a9b2322003-11-22 01:14:58 +0000202
Chris Lattner0548bc22003-11-26 08:20:34 +0000203<li>Constant initializers now generate loops instead of potentially <a href="http://llvm.cs.uiuc.edu/PR75">huge amounts of straight-line code</a>.</li>
204
Chris Lattner8139b782003-11-27 09:51:54 +0000205<li>Code for running C++ destructors is now properly shared when possible. Before, the C++ front-end
206<a href="http://llvm.cs.uiuc.edu/PR11">generated N^2 amounts of duplicated cleanup code</a> in some cases.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000207</ol>
Chris Lattner639579c2003-10-27 17:06:39 +0000208
Chris Lattnerba7bd472003-12-06 20:22:41 +0000209
210<!--=========================================================================-->
211<div class="doc_subsubsection">
212In this release, the following bugs in the previous release were fixed:
213</div>
214
215<p>Bugs in the LLVM Core:</p>
Chris Lattnere7525b52003-10-07 21:38:31 +0000216
217<ol>
Chris Lattner25fd5c12003-10-27 05:41:39 +0000218<li><a href="http://llvm.cs.uiuc.edu/PR57">[inliner] Inlining invoke with PHI in unwind target is broken</a></li>
Chris Lattner639579c2003-10-27 17:06:39 +0000219<li><a href="http://llvm.cs.uiuc.edu/PR58">[linker] linkonce globals should link successfully to external globals</a></li>
Chris Lattnera1a090e2003-10-29 07:17:13 +0000220<li><a href="http://llvm.cs.uiuc.edu/PR64">[constmerge] Constant merging pass merges constants with external linkage</a></li>
Chris Lattner5b83b562003-10-29 18:49:14 +0000221<li><a href="http://llvm.cs.uiuc.edu/PR66">[scalarrepl] Scalar Replacement of aggregates is decimating structures it shouldn't be</a></li>
Chris Lattnera2bd4e02003-10-30 01:20:42 +0000222<li><a href="http://llvm.cs.uiuc.edu/PR70">[instcombine] Resolving invoke inserts cast after terminator</a></li>
Chris Lattnera306dd22003-10-30 01:43:33 +0000223<li><a href="http://llvm.cs.uiuc.edu/PR71">llvm-as crashes when labels are used in phi nodes</a></li>
Chris Lattnerb45e1f92003-10-30 16:20:15 +0000224<li><a href="http://llvm.cs.uiuc.edu/PR72">[build problem] Callgraph.cpp not pulled in from libipa.a</a></li>
Chris Lattner9dd6a822003-11-16 22:11:42 +0000225<li><a href="http://llvm.cs.uiuc.edu/PR77">Variables in scope of output setjmp
Chris Lattnerba7bd472003-12-06 20:22:41 +0000226calls should be volatile</a> (Note that this does not effect correctness on
227many platforms, such as X86).</li>
Chris Lattneref114d52003-11-03 20:08:08 +0000228<li><a href="http://llvm.cs.uiuc.edu/PR83">[X86] Emission of global bool initializers broken</a></li>
Chris Lattnerab77bc52003-11-05 06:30:04 +0000229<li><a href="http://llvm.cs.uiuc.edu/PR91">[gccld] The -r (relinking) option does not work correctly</a></li>
Chris Lattner34596d72003-11-07 04:46:56 +0000230<li><a href="http://llvm.cs.uiuc.edu/PR92">[bcreader] Cannot read shift constant expressions from bytecode file</a></li>
231<li><a href="http://llvm.cs.uiuc.edu/PR93">[lowersetjmp] Lowersetjmp pass breaks dominance properties!</a></li>
Chris Lattner881cb482003-11-09 19:44:07 +0000232<li><a href="http://llvm.cs.uiuc.edu/PR95">SymbolTable::getUniqueName is very inefficient</a></li>
Brian Gaeke4c563b82003-12-11 04:40:58 +0000233<li><a href="http://llvm.cs.uiuc.edu/PR97">bugpoint must not pass -R&lt;directory&gt; to Mach-O linker</a></li>
Chris Lattner34596d72003-11-07 04:46:56 +0000234<li><a href="http://llvm.cs.uiuc.edu/PR98">[buildscripts] Building into objdir with .o in it fails</a></li>
Chris Lattner699a58d2003-11-08 05:18:50 +0000235<li><a href="http://llvm.cs.uiuc.edu/PR101">[setjmp/longjmp] Linking C programs which use setjmp/longjmp sometimes fail with references to the C++ runtime library!</a></li>
Chris Lattnera7235372003-11-12 04:42:37 +0000236<li><a href="http://llvm.cs.uiuc.edu/PR107">AsmParser Misses Symbol Redefinition Error</a></li>
Brian Gaeke7aeb2b72003-11-11 21:52:34 +0000237<li><a href="http://llvm.cs.uiuc.edu/PR108">gccld -Lfoo -lfoo fails to find ./foo/libfoo.a</a></li>
Chris Lattner7c04a292003-11-14 06:42:01 +0000238<li><a href="http://llvm.cs.uiuc.edu/PR110">[bcreader] Incorrect cast causes misread forward constant references</a></li>
Chris Lattner2f486b82003-11-16 21:42:48 +0000239<li><a href="http://llvm.cs.uiuc.edu/PR116">[adce] ADCE considers blocks without postdominators to be unreachable</a></li>
Chris Lattnercf40b3f2003-11-18 23:04:02 +0000240<li><a href="http://llvm.cs.uiuc.edu/PR123">[X86] div and rem constant exprs invalidate iterators!</a></li>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000241<li><a href="http://llvm.cs.uiuc.edu/PR130">[vmcore] Symbol table doesn't rename colliding variables during type resolution</a></li>
Brian Gaeke4c563b82003-12-11 04:40:58 +0000242<li><a href="http://llvm.cs.uiuc.edu/PR138">Archive reader does not understand 4.4BSD/Mac OS X long filenames</a></li>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000243<li><a href="http://llvm.cs.uiuc.edu/PR140">gccld produces a runner script that includes command-line options to load the necessary shared objects</a></li>
244</ol>
245
246
247<p>Bugs in the C/C++ front-end:</p>
248
249<ol>
250<li><a href="http://llvm.cs.uiuc.edu/PR59">C++ frontend can crash when compiling virtual base classes</a></li>
251<li><a href="http://llvm.cs.uiuc.edu/PR62">C backend fails on constant cast expr to ptr-to-anonymous struct</a></li>
252<li><a href="http://llvm.cs.uiuc.edu/PR63">#ident is not recognized by C frontend</a></li>
253<li><a href="http://llvm.cs.uiuc.edu/PR65">C front-end miscompiles the builtin_expect intrinsic!</a></li>
254<li><a href="http://llvm.cs.uiuc.edu/PR67">1.0 precompiled libstdc++ does not include wchar_t support</a></li>
255<li><a href="http://llvm.cs.uiuc.edu/PR68">llvmgcc asserts when compiling functions renamed with asm's</a></li>
256<li><a href="http://llvm.cs.uiuc.edu/PR69">C frontend crashes on some programs with lots of types.</a></li>
257<li><a href="http://llvm.cs.uiuc.edu/PR79">llvm-gcc crashes compiling global union initializer</a></li>
258<li><a href="http://llvm.cs.uiuc.edu/PR80">C front-end crash on empty structure</a></li>
259<li><a href="http://llvm.cs.uiuc.edu/PR81">CFrontend crashes when compiling C99 compound expressions</a></li>
260<li><a href="http://llvm.cs.uiuc.edu/PR87">llvm-gcc infinite loops on "case MAXINT:"</a></li>
261<li><a href="http://llvm.cs.uiuc.edu/PR89">[C++] Catch blocks make unparsable labels</a></li>
262<li><a href="http://llvm.cs.uiuc.edu/PR90">[C++] Initializing array with constructable objects fail</a></li>
263<li><a href="http://llvm.cs.uiuc.edu/PR94">llvm-gcc tries to add bools</a></li>
264<li><a href="http://llvm.cs.uiuc.edu/PR104">[c++] C++ Frontend lays out superclasses like anonymous bitfields!</a></li>
265<li><a href="http://llvm.cs.uiuc.edu/PR54">C front-end miscompiles unsigned enums whose LLVM types are signed</a></li>
266<li><a href="http://llvm.cs.uiuc.edu/PR112">Casting a string constant to void crashes llvm-gcc</a></li>
Chris Lattnercf40b3f2003-11-18 23:04:02 +0000267<li><a href="http://llvm.cs.uiuc.edu/PR125">[llvmg++] Enum types are incorrectly shrunk to smaller than 'int' size</a></li>
268<li><a href="http://llvm.cs.uiuc.edu/PR128">[llvmg++] Cannot use pointer to member to initialize global</a></li>
Chris Lattner983c6672003-11-19 01:08:24 +0000269<li><a href="http://llvm.cs.uiuc.edu/PR131">[llvm-gcc] ?: operator as lvalue not implemented</a></li>
Chris Lattner592db402003-11-19 22:05:38 +0000270<li><a href="http://llvm.cs.uiuc.edu/PR133">[C/C++] Bogus warning about taking the address of 'register' variable</a></li>
Chris Lattnerc4fe9722003-11-20 01:07:41 +0000271<li><a href="http://llvm.cs.uiuc.edu/PR113">crash assigning into an array in a struct which contains a bitfield</a>.</li>
272<li><a href="http://llvm.cs.uiuc.edu/PR6">Oversized integer bitfields cause crash</a></li>
Chris Lattner0548bc22003-11-26 08:20:34 +0000273<li><a href="http://llvm.cs.uiuc.edu/PR141">[llvm-gcc] Bitfields &amp; large array don't mix well</a></li>
Chris Lattner16bbed22003-11-20 19:30:17 +0000274<li><a href="http://llvm.cs.uiuc.edu/PR132">[llvm-gcc] Complex division is not supported</a></li>
Chris Lattner5eac2d62003-11-20 20:59:57 +0000275<li><a href="http://llvm.cs.uiuc.edu/PR143">[llvm-gcc] Illegal union field reference</a></li>
Chris Lattner83f43a02003-11-25 08:49:12 +0000276<li><a href="http://llvm.cs.uiuc.edu/PR148">[llvmg++] Front-end attempts to return structure by value</a></li>
Chris Lattner86d5c1c2003-11-26 01:18:49 +0000277<li><a href="http://llvm.cs.uiuc.edu/PR152">[llvmg++] Pointer to member initializers not supported in constructors</a></li>
278<li><a href="http://llvm.cs.uiuc.edu/PR155">[llvm-gcc] crash on union initialization</a></li>
Chris Lattnerb27353c2003-11-26 02:48:00 +0000279<li><a href="http://llvm.cs.uiuc.edu/PR124">[llvm-g++] ?: expressions do not run correct number of destructors!</a></li>
Chris Lattner0548bc22003-11-26 08:20:34 +0000280<li><a href="http://llvm.cs.uiuc.edu/PR157">[llvm-gcc] Pointer & constant results in invalid shift</a></li>
Chris Lattnerd2a55f302003-12-08 06:33:19 +0000281<li><a href="http://llvm.cs.uiuc.edu/PR165">[llvmg++] call through array of pointers to member functions causes assertion</a></li>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000282</ol>
Chris Lattner62495762003-10-02 16:38:05 +0000283
Misha Brukman80731b92003-11-22 00:38:41 +0000284</div>
Chris Lattner62495762003-10-02 16:38:05 +0000285
286<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000287<div class="doc_section">
288 <a name="portability">Portability and Supported Platforms</a>
289</div>
Chris Lattner62495762003-10-02 16:38:05 +0000290<!-- *********************************************************************** -->
291
Misha Brukman80731b92003-11-22 00:38:41 +0000292<div class="doc_text">
293
294<p>LLVM has been extensively tested on Intel and AMD machines running Red
Chris Lattner14b5d5a2003-11-08 05:22:09 +0000295Hat Linux, and Sun UltraSPARC workstations running Solaris 8. Additionally,
Chris Lattnere76e9ab2003-12-12 04:25:33 +0000296LLVM works on Mac OS/X 10.3 and above, but only with the C backend or
297interpreter (no native backend for the PowerPC is available yet).
Chris Lattner62495762003-10-02 16:38:05 +0000298The core LLVM infrastructure uses "autoconf" for portability, so hopefully we
Chris Lattner14b5d5a2003-11-08 05:22:09 +0000299work on more platforms than that. However, it is likely that we
300missed something, and that minor porting is required to get LLVM to work on
Misha Brukman80731b92003-11-22 00:38:41 +0000301new platforms. We welcome portability patches and error messages.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000302
Misha Brukman80731b92003-11-22 00:38:41 +0000303</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000304
305<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000306<div class="doc_section">
307 <a name="knownproblems">Known Problems</a>
308</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000309<!-- *********************************************************************** -->
310
Misha Brukman80731b92003-11-22 00:38:41 +0000311<div class="doc_text">
312
313<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner3d482502003-10-02 04:57:28 +0000314component. As new problems are discovered, they will be added to these
Misha Brukman80731b92003-11-22 00:38:41 +0000315sections.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000316
Misha Brukman80731b92003-11-22 00:38:41 +0000317</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000318
319<!-- _______________________________________________________________________ -->
Chris Lattner62495762003-10-02 16:38:05 +0000320<!--
Chris Lattner3d482502003-10-02 04:57:28 +0000321</ul><h4><a name="portability"><hr size=0>Portability Problems</h4><ul>
Chris Lattner62495762003-10-02 16:38:05 +0000322-->
Chris Lattner3d482502003-10-02 04:57:28 +0000323
324
Misha Brukman80731b92003-11-22 00:38:41 +0000325<!-- ======================================================================= -->
326<div class="doc_subsection">
327 <a name="core">Known problems with the LLVM Core</a>
328</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000329
Misha Brukman80731b92003-11-22 00:38:41 +0000330<div class="doc_text">
331
332<ul>
333
334<li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not
335work.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000336
337<li>The JIT does not use mutexes to protect its internal data structures. As
Misha Brukman80731b92003-11-22 00:38:41 +0000338such, execution of a threaded program could cause these data structures to be
339corrupted.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000340
Misha Brukman80731b92003-11-22 00:38:41 +0000341<li>It is not possible to <tt>dlopen</tt> an LLVM bytecode file in the JIT.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000342
Chris Lattnera623e482003-10-20 19:05:03 +0000343<li>Linking in static archive files (.a files) is very slow (there is no symbol
Misha Brukman80731b92003-11-22 00:38:41 +0000344table in the archive).</li>
Chris Lattnerc679fbb2003-11-04 20:06:53 +0000345
Chris Lattnerc679fbb2003-11-04 20:06:53 +0000346<li><a href="http://llvm.cs.uiuc.edu/PR82">LLVM cannot handle structures with
Misha Brukman80731b92003-11-22 00:38:41 +0000347more than 256 elements</a>.</li>
348
349</ul>
350
351</div>
352
353<!-- ======================================================================= -->
354<div class="doc_subsection">
355 <a name="c-fe">Known problems with the C front-end</a>
356</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000357
Chris Lattner3d482502003-10-02 04:57:28 +0000358<!-- _______________________________________________________________________ -->
Misha Brukman80731b92003-11-22 00:38:41 +0000359<div class="doc_subsubsection">
360 Bugs
361</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000362
Misha Brukman80731b92003-11-22 00:38:41 +0000363<div class="doc_text">
364
365<ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000366
Chris Lattner3d482502003-10-02 04:57:28 +0000367<li>C99 Variable sized arrays do not release stack memory when they go out of
368 scope. Thus, the following program may run out of stack space:
369<pre>
370 for (i = 0; i != 1000000; ++i) {
371 int X[n];
372 foo(X);
373 }
Misha Brukman80731b92003-11-22 00:38:41 +0000374</pre></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000375
Misha Brukman80731b92003-11-22 00:38:41 +0000376</ul>
Chris Lattnerd2a74272003-10-27 18:30:37 +0000377
Misha Brukman80731b92003-11-22 00:38:41 +0000378</div>
379
380<!-- _______________________________________________________________________ -->
381<div class="doc_subsubsection">
382 Notes
383</div>
384
385<div class="doc_text">
386
387<ul>
388
389<li>Inline assembly is not yet supported.</li>
Chris Lattnerd2a74272003-10-27 18:30:37 +0000390
391<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman80731b92003-11-22 00:38:41 +0000392support for floating point data types of any size other than 32 and 64
393bits.</li>
394
395<li>The following Unix system functionality has not been tested and may not
396work:
Misha Brukman7cb4e382003-11-22 01:00:11 +0000397 <ol>
398 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
399 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
400 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
401 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
402 - These functions have not been tested.
403 </ol></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000404
405<li>Although many GCC extensions are supported, some are not. In particular,
406 the following extensions are known to <b>not be</b> supported:
407 <ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000408 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
409 <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>
410 <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>
411 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
412 <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>
413 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands</li>
414 <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>
415 <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>
416 <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>
417 <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>
418 <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>
419 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables.</li>
420 <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 +0000421 </ol>
Chris Lattner3d482502003-10-02 04:57:28 +0000422
Misha Brukman80731b92003-11-22 00:38:41 +0000423 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner3d482502003-10-02 04:57:28 +0000424 attribute means that the LLVM compiler ignores the presence of the attribute,
425 but the code should still work. An unsupported attribute is one which is
426 ignored by the LLVM compiler, which will cause a different interpretation of
Misha Brukman80731b92003-11-22 00:38:41 +0000427 the program.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000428
429 <ol>
430 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
431 Arrays whose length is computed at run time.<br>
Misha Brukman80731b92003-11-22 00:38:41 +0000432 Supported, but allocated stack space is not freed until the function returns (noted above).</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000433
434 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Misha Brukman80731b92003-11-22 00:38:41 +0000435
436 Declaring that functions have no side effects, or that they can never
437 return.<br>
438
439 <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
440 <tt>constructor</tt>, <tt>destructor</tt>, <tt>unused</tt>,
441 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
442
443 <b>Ignored:</b> <tt>noreturn</tt>, <tt>noinline</tt>,
444 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
445 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
446
447 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>,
448 <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
449 <tt>fastcall</tt>, all other target specific attributes</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000450
451 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
452 Specifying attributes of variables.<br>
453 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
454 <tt>deprecated</tt>, <tt>transparent_union</tt>,
455 <tt>unused</tt>, <tt>weak</tt><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000456
Chris Lattner3d482502003-10-02 04:57:28 +0000457 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
458 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
459 <tt>vector_size</tt>, <tt>dllimport</tt>,
Misha Brukman80731b92003-11-22 00:38:41 +0000460 <tt>dllexport</tt>, all target specific attributes.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000461
Misha Brukman8395d732003-12-12 04:37:31 +0000462 <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 +0000463 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukman8395d732003-12-12 04:37:31 +0000464 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000465
466 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
467 all target specific attributes.</li>
468
Chris Lattner3d482502003-10-02 04:57:28 +0000469 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
470 Other built-in functions.<br>
471 We support all builtins which have a C language equivalent (e.g.,
472 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
473 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Misha Brukman80731b92003-11-22 00:38:41 +0000474 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt> (ignored).</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000475
Misha Brukman80731b92003-11-22 00:38:41 +0000476 </ol>
Chris Lattner3d482502003-10-02 04:57:28 +0000477
Misha Brukman80731b92003-11-22 00:38:41 +0000478 <p>The following extensions <b>are</b> known to be supported:</p>
479
Chris Lattner3d482502003-10-02 04:57:28 +0000480 <ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000481 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
482 <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>
483 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
484 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
485 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
486 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
487 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
488 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
489 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
490 <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>
491 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
492 <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 +0000493 <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 +0000494 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
495 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions or arrays as values.</li>
496 <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 +0000497 <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 +0000498 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
499 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
500 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
501 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized.</li>
502 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
503 <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>
504 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
505 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
506 <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>
507 <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>
508 <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>
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 +0000511 </ol></li>
512
513</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000514
Misha Brukman80731b92003-11-22 00:38:41 +0000515<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 +0000517
Misha Brukman80731b92003-11-22 00:38:41 +0000518</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000519
Misha Brukman80731b92003-11-22 00:38:41 +0000520<!-- ======================================================================= -->
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 +0000524
Misha Brukman80731b92003-11-22 00:38:41 +0000525<div class="doc_text">
526
Chris Lattnere76e9ab2003-12-12 04:25:33 +0000527<p>For this release, the C++ front-end is considered to be fully functional, but
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 +0000531
532</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000533
534<!-- _______________________________________________________________________ -->
Misha Brukman80731b92003-11-22 00:38:41 +0000535<div class="doc_subsubsection">
536 Bugs
537</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000538
Misha Brukman80731b92003-11-22 00:38:41 +0000539<div class="doc_text">
Chris Lattner3d482502003-10-02 04:57:28 +0000540
Misha Brukman80731b92003-11-22 00:38:41 +0000541<ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000542<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
Misha Brukman80731b92003-11-22 00:38:41 +0000543 front-end</a></li>
544</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000545
Misha Brukman80731b92003-11-22 00:38:41 +0000546</div>
547
548<!-- _______________________________________________________________________ -->
549<div class="doc_subsubsection">
550 Notes
551</div>
552
553<div class="doc_text">
554
555<ul>
Chris Lattnerd2a74272003-10-27 18:30:37 +0000556
Chris Lattner3d482502003-10-02 04:57:28 +0000557<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
558parser is significantly more standards compliant (and picky) than prior GCC
559versions. For more information, see the C++ section of the <a
Chris Lattnere76e9ab2003-12-12 04:25:33 +0000560href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000561
562<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
Chris Lattner62495762003-10-02 16:38:05 +0000563 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner3d482502003-10-02 04:57:28 +0000564 function and in the <tt>setjmp</tt> receiver function may not be run.
565 Objects in intervening stack frames will be destroyed however (which is
Misha Brukman80731b92003-11-22 00:38:41 +0000566 better than most compilers).</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000567
Chris Lattner62495762003-10-02 16:38:05 +0000568<li>The LLVM C++ front-end follows the <a
569 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
570 This document, which is not Itanium specific, specifies a standard for name
571 mangling, class layout, v-table layout, RTTI formats, and other C++
572 representation issues. Because we use this API, code generated by the LLVM
573 compilers should be binary compatible with machine code generated by other
574 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
575 <i>However</i>, the exception handling mechanism used by LLVM is very
576 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman80731b92003-11-22 00:38:41 +0000577 interact correctly</b>. </li>
Chris Lattner3d482502003-10-02 04:57:28 +0000578
Misha Brukman80731b92003-11-22 00:38:41 +0000579</ul>
Chris Lattner46ecf612003-10-07 22:14:37 +0000580
Misha Brukman80731b92003-11-22 00:38:41 +0000581</div>
582
583<!-- ======================================================================= -->
584<div class="doc_subsection">
585 <a name="x86-be">Known problems with the X86 back-end</a>
586</div>
587
588<div class="doc_text">
589
590<ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000591
Chris Lattner46ecf612003-10-07 22:14:37 +0000592<li>The X86 code generator <a
Chris Lattnerc4788bb2003-10-08 06:01:38 +0000593href="http://llvm.cs.uiuc.edu/PR16">does not currently
Chris Lattner46ecf612003-10-07 22:14:37 +0000594support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
Misha Brukman80731b92003-11-22 00:38:41 +0000595or calls the C <tt>longjmp</tt> function will abort.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000596
Misha Brukman80731b92003-11-22 00:38:41 +0000597</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000598
Misha Brukman80731b92003-11-22 00:38:41 +0000599</div>
600
601<!-- ======================================================================= -->
602<div class="doc_subsection">
603 <a name="sparc-be">Known problems with the Sparc back-end</a>
604</div>
605
606<div class="doc_text">
607
608<ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000609
Chris Lattner46ecf612003-10-07 22:14:37 +0000610<li>The Sparc code generator <a
Chris Lattnerc4788bb2003-10-08 06:01:38 +0000611href="http://llvm.cs.uiuc.edu/PR15">does not currently
Chris Lattner46ecf612003-10-07 22:14:37 +0000612support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
Misha Brukman80731b92003-11-22 00:38:41 +0000613or calls the C <tt>longjmp</tt> function will abort.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000614
Misha Brukman80731b92003-11-22 00:38:41 +0000615</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000616
Misha Brukman80731b92003-11-22 00:38:41 +0000617</div>
618
619<!-- ======================================================================= -->
620<div class="doc_subsection">
621 <a name="c-be">Known problems with the C back-end</a>
622</div>
623
624<div class="doc_text">
625
626<ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000627
628<li>The C back-end produces code that violates the ANSI C Type-Based Alias
629Analysis rules. As such, special options may be necessary to compile the code
630(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
Misha Brukman80731b92003-11-22 00:38:41 +0000631problem probably cannot be fixed.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000632
Chris Lattnera623e482003-10-20 19:05:03 +0000633<li><a href="http://llvm.cs.uiuc.edu/PR33">Initializers for global variables</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000634cannot include special floating point numbers like Not-A-Number or
635Infinity.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000636
Chris Lattnerc679fbb2003-11-04 20:06:53 +0000637<li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
Chris Lattnerb28c3282003-10-24 04:03:19 +0000638supported</a>. This should not affect LLVM produced by the C or C++
Misha Brukman80731b92003-11-22 00:38:41 +0000639frontends.</li>
Chris Lattnerb28c3282003-10-24 04:03:19 +0000640
Misha Brukman80731b92003-11-22 00:38:41 +0000641</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000642
Misha Brukman80731b92003-11-22 00:38:41 +0000643</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000644
645<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000646<div class="doc_section">
647 <a name="additionalinfo">Additional Information</a>
648</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000649<!-- *********************************************************************** -->
650
Misha Brukman80731b92003-11-22 00:38:41 +0000651<div class="doc_text">
652
653<p>A wide variety of additional information is available on the LLVM web page,
Chris Lattner3d482502003-10-02 04:57:28 +0000654including mailing lists publications describing algorithms and components
655implemented in LLVM. The web page also contains versions of the API
656documentation which is up-to-date with the CVS version of the source code. You
657can access versions of these documents specific to this release by going into
Misha Brukman80731b92003-11-22 00:38:41 +0000658the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000659
Misha Brukman80731b92003-11-22 00:38:41 +0000660<p>If you have any questions or comments about LLVM, please feel free to contact
661us via the mailing lists.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000662
Misha Brukman80731b92003-11-22 00:38:41 +0000663</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000664
665<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000666
Misha Brukman80731b92003-11-22 00:38:41 +0000667<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000668<address>
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Misha Brukman7cb4e382003-11-22 01:00:11 +0000674 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
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Misha Brukman68aab3b2003-11-22 01:23:39 +0000676</address>
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