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John Criswell98391ce2005-05-18 20:28:46 +00007 <title>LLVM 1.6 Release Notes</title>
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9<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +000010
John Criswell98391ce2005-05-18 20:28:46 +000011<div class="doc_title">LLVM 1.6 Release Notes</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000012
13<ol>
Misha Brukman500bc302003-11-22 00:38:41 +000014 <li><a href="#intro">Introduction</a></li>
15 <li><a href="#whatsnew">What's New?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +000016 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +000017 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +000018 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman500bc302003-11-22 00:38:41 +000019 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +000020</ol>
21
Chris Lattner7911ce22004-05-23 21:07:27 +000022<div class="doc_author">
Chris Lattner78bf32b2004-12-09 22:22:58 +000023 <p>Written by the <a href="http://llvm.cs.uiuc.edu">LLVM Team</a><p>
Misha Brukman500bc302003-11-22 00:38:41 +000024</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000025
26<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +000027<div class="doc_section">
28 <a name="intro">Introduction</a>
29</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000030<!-- *********************************************************************** -->
31
Misha Brukman500bc302003-11-22 00:38:41 +000032<div class="doc_text">
33
34<p>This document contains the release notes for the LLVM compiler
John Criswell98391ce2005-05-18 20:28:46 +000035infrastructure, release 1.6. Here we describe the status of LLVM, including any
Chris Lattner8a458762005-05-15 05:44:51 +000036known problems and major improvements from the previous release. The most
37up-to-date version of this document can be found on the <a
John Criswell98391ce2005-05-18 20:28:46 +000038href="http://llvm.cs.uiuc.edu/releases/1.6/">LLVM 1.6 web site</a>. If you are
John Criswelld000e1d2003-12-18 16:43:17 +000039not reading this on the LLVM web pages, you should probably go there because
Misha Brukman500bc302003-11-22 00:38:41 +000040this document may be updated after the release.</p>
Chris Lattner19092612003-10-02 16:38:05 +000041
Chris Lattner7506b1d2004-12-07 08:04:13 +000042<p>For more information about LLVM, including information about the latest
43release, please check out the <a href="http://llvm.cs.uiuc.edu">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +000044web site</a>. If you have questions or comments, the <a
45href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman500bc302003-11-22 00:38:41 +000046list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +000047
Chris Lattner78bf32b2004-12-09 22:22:58 +000048<p>Note that if you are reading this file from CVS or the main LLVM web page,
49this document applies to the <i>next</i> release, not the current one. To see
50the release notes for the current or previous releases, see the <a
Misha Brukman500bc302003-11-22 00:38:41 +000051href="http://llvm.cs.uiuc.edu/releases/">releases page</a>.</p>
52
53</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000054
55<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +000056<div class="doc_section">
57 <a name="whatsnew">What's New?</a>
58</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000059<!-- *********************************************************************** -->
60
Misha Brukman500bc302003-11-22 00:38:41 +000061<div class="doc_text">
62
John Criswell98391ce2005-05-18 20:28:46 +000063<p>This is the seventh public release of the LLVM Compiler Infrastructure.</p>
Chris Lattnera5099962003-12-06 20:22:41 +000064
John Criswell98391ce2005-05-18 20:28:46 +000065<p>LLVM 1.6 is known to correctly compile a wide range of C and C++ programs,
66includes bug fixes for those problems found since the 1.5 release, and includes
Chris Lattnerbf307012005-05-16 16:56:09 +000067a large number of new features and enhancements, described below.</p>
Chris Lattnera5099962003-12-06 20:22:41 +000068
Chris Lattner80453c92004-05-24 04:50:25 +000069</div>
70
Chris Lattnera5099962003-12-06 20:22:41 +000071<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +000072<div class="doc_subsection">
John Criswell98391ce2005-05-18 20:28:46 +000073<a name="newfeatures">New Features in LLVM 1.6</a>
Chris Lattner80453c92004-05-24 04:50:25 +000074</div>
Brian Gaeke6b31beb2004-01-16 21:55:04 +000075
Chris Lattnerebc8c7d2005-05-18 22:23:56 +000076<div class="doc_text">
77<h1>
78 See <a href="/releases/1.5/docs/ReleaseNotes.html">LLVM 1.5 Release Notes</a>
79</h1>
Reid Spencerfce2ddc2005-07-12 16:36:24 +000080<ol>
81 <li>The JIT now uses mutexes to protect its internal data structures. This
82 allows multi-threaded programs to be run from the JIT or interpreter without
83 corruption of the internal data structures. See
84 <a href="http://llvm.cs.uiuc.edu/PR418">PR418</a> and
85 <a href="http://llvm.cs.uiuc.edu/PR540">PR540</a> for the details.
86 </li>
87</ol>
Chris Lattnerebc8c7d2005-05-18 22:23:56 +000088</div>
89
Brian Gaeke6b31beb2004-01-16 21:55:04 +000090<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +000091<div class="doc_subsection">
John Criswell98391ce2005-05-18 20:28:46 +000092<a name="codequality">Code Quality Improvements in LLVM 1.6</a>
Chris Lattneraab56d42004-05-23 20:42:08 +000093</div>
Chris Lattner89ca2b82003-10-27 17:06:39 +000094
Chris Lattnerbf307012005-05-16 16:56:09 +000095<!--=========================================================================-->
96<div class="doc_subsection">
John Criswell98391ce2005-05-18 20:28:46 +000097<a name="codequality">Code Generator Improvements in LLVM 1.6</a>
Chris Lattnerbf307012005-05-16 16:56:09 +000098</div>
99
Chris Lattnera5099962003-12-06 20:22:41 +0000100<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000101<div class="doc_subsection">
John Criswell98391ce2005-05-18 20:28:46 +0000102<a name="bugfix">Significant Bugs Fixed in LLVM 1.6</a>
Chris Lattner80453c92004-05-24 04:50:25 +0000103</div>
Reid Spencer8e0262f2004-05-23 17:23:13 +0000104
John Criswelle531ec52005-06-29 16:22:34 +0000105<div class="doc_text">
106<ol>
107 <li><a href="http://llvm.cs.uiuc.edu/PR591">[simplify-libcalls] The simplify-libcalls pass generates ill-formed LLVM code</a>.</li>
108</ol>
109</div>
110
Chris Lattner19092612003-10-02 16:38:05 +0000111<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000112<div class="doc_section">
113 <a name="portability">Portability and Supported Platforms</a>
114</div>
Chris Lattner19092612003-10-02 16:38:05 +0000115<!-- *********************************************************************** -->
116
Misha Brukman500bc302003-11-22 00:38:41 +0000117<div class="doc_text">
118
John Criswell0b5b5e92004-12-08 20:35:47 +0000119<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000120
121<ul>
Reid Spencer00812e22005-05-17 02:47:27 +0000122 <li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
123 (and probably other unix-like systems).</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000124<li>Sun UltraSPARC workstations running Solaris 8.</li>
Chris Lattner7506b1d2004-12-07 08:04:13 +0000125<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
126 support is available for native builds with Visual C++).</li>
127<li>PowerPC-based Mac OS X systems, running 10.2 and above.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000128<li>Alpha-based machines running Debian GNU/Linux.</li>
129<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000130</ul>
131
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000132<p>The core LLVM infrastructure uses
133<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
134to the machine and operating system on which it is built. However, minor
135porting may be required to get LLVM to work on new platforms. We welcome your
136portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000137
Misha Brukman500bc302003-11-22 00:38:41 +0000138</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000139
140<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000141<div class="doc_section">
142 <a name="knownproblems">Known Problems</a>
143</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000144<!-- *********************************************************************** -->
145
Misha Brukman500bc302003-11-22 00:38:41 +0000146<div class="doc_text">
147
148<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000149component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000150sections. If you run into a problem, please check the <a
John Criswelld000e1d2003-12-18 16:43:17 +0000151href="http://llvm.cs.uiuc.edu/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000152there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000153
Misha Brukman500bc302003-11-22 00:38:41 +0000154</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000155
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000156<!-- ======================================================================= -->
157<div class="doc_subsection">
158 <a name="experimental">Experimental features included with this release</a>
159</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000160
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000161<div class="doc_text">
162
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000163<p>The following components of this LLVM release are either untested, known to
164be broken or unreliable, or are in early development. These components should
165not be relied on, and bugs should not be filed against them, but they may be
166useful to some people. In particular, if you would like to work on one of these
167components, please contact us on the llvmdev list.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000168
169<ul>
Chris Lattner7506b1d2004-12-07 08:04:13 +0000170<li>The following passes are incomplete or buggy, and may be removed in future
Chris Lattnere9412172005-10-24 02:33:44 +0000171 releases: <tt>-cee, -pre</tt></li>
Chris Lattner7506b1d2004-12-07 08:04:13 +0000172<li>The <tt>llvm-db</tt> tool is in a very early stage of development, but can
173 be used to step through programs and inspect the stack.</li>
Misha Brukman109d9e82005-03-30 19:14:24 +0000174<li>The "iterative scan" register allocator (enabled with
175 <tt>-regalloc=iterativescan</tt>) is not stable.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000176<li>The SparcV8, Alpha, and IA64 code generators are experimental.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000177</ul>
178
179</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000180
Misha Brukman500bc302003-11-22 00:38:41 +0000181<!-- ======================================================================= -->
182<div class="doc_subsection">
183 <a name="core">Known problems with the LLVM Core</a>
184</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000185
Misha Brukman500bc302003-11-22 00:38:41 +0000186<div class="doc_text">
187
188<ul>
Misha Brukman109d9e82005-03-30 19:14:24 +0000189 <li>In the JIT, <tt>dlsym()</tt> on a symbol compiled by the JIT will not
190 work.</li>
Reid Spencer4f86f9c2004-11-25 22:38:30 +0000191 <li><a href="http://llvm.cs.uiuc.edu/PR240">The lower-invoke pass does not
192 mark values live across a setjmp as volatile</a>. This missing feature
193 only affects targets whose setjmp/longjmp libraries do not save and restore
194 the entire register file.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000195</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000196</div>
197
198<!-- ======================================================================= -->
199<div class="doc_subsection">
200 <a name="c-fe">Known problems with the C front-end</a>
201</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000202
Chris Lattner79c3fe12003-10-02 04:57:28 +0000203<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000204<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000205
Misha Brukman500bc302003-11-22 00:38:41 +0000206<div class="doc_text">
Misha Brukman500bc302003-11-22 00:38:41 +0000207<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000208<li>C99 Variable sized arrays do not release stack memory when they go out of
209 scope. Thus, the following program may run out of stack space:
210<pre>
211 for (i = 0; i != 1000000; ++i) {
212 int X[n];
213 foo(X);
214 }
Misha Brukman500bc302003-11-22 00:38:41 +0000215</pre></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000216
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000217<li>Initialization of global union variables can only be done <a
Misha Brukman43ee2932004-12-04 00:45:09 +0000218href="http://llvm.cs.uiuc.edu/PR162">with the largest union member</a>.</li>
Chris Lattnerf580cdc2004-03-16 21:39:04 +0000219
John Criswelld000e1d2003-12-18 16:43:17 +0000220</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000221</div>
222
223<!-- _______________________________________________________________________ -->
224<div class="doc_subsubsection">
225 Notes
226</div>
227
228<div class="doc_text">
229
230<ul>
231
232<li>Inline assembly is not yet supported.</li>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000233
234<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman500bc302003-11-22 00:38:41 +0000235support for floating point data types of any size other than 32 and 64
236bits.</li>
237
238<li>The following Unix system functionality has not been tested and may not
239work:
Misha Brukmane0c891c2003-11-22 01:00:11 +0000240 <ol>
241 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
242 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
243 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
244 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
245 - These functions have not been tested.
246 </ol></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000247
248<li>Although many GCC extensions are supported, some are not. In particular,
249 the following extensions are known to <b>not be</b> supported:
250 <ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000251 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000252 <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>
253 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
254 <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 +0000255 <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 +0000256 <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>
257 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Explicit-Reg-Vars.html#Explicit%20Reg%20Vars">Explicit Reg Vars</a>: Defining variables residing in specified registers.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000258 <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>
259 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.</li>
Tanya Lattner014e5f52004-12-08 18:25:34 +0000260 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000261 <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 +0000262 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000263
Misha Brukman500bc302003-11-22 00:38:41 +0000264 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner79c3fe12003-10-02 04:57:28 +0000265 attribute means that the LLVM compiler ignores the presence of the attribute,
266 but the code should still work. An unsupported attribute is one which is
John Criswelld000e1d2003-12-18 16:43:17 +0000267 ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman500bc302003-11-22 00:38:41 +0000268 the program.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000269
270 <ol>
271 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
272 Arrays whose length is computed at run time.<br>
Misha Brukman500bc302003-11-22 00:38:41 +0000273 Supported, but allocated stack space is not freed until the function returns (noted above).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000274
275 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Misha Brukman500bc302003-11-22 00:38:41 +0000276
John Criswelld000e1d2003-12-18 16:43:17 +0000277 Declaring that functions have no side effects or that they can never
Misha Brukman500bc302003-11-22 00:38:41 +0000278 return.<br>
279
280 <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
John Criswell0b5b5e92004-12-08 20:35:47 +0000281 <tt>noreturn</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
282 <tt>unused</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000283 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
284
John Criswell0b5b5e92004-12-08 20:35:47 +0000285 <b>Ignored:</b> <tt>noinline</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000286 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
287 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
288
289 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>,
290 <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
291 <tt>fastcall</tt>, all other target specific attributes</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000292
293 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
294 Specifying attributes of variables.<br>
295 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
296 <tt>deprecated</tt>, <tt>transparent_union</tt>,
297 <tt>unused</tt>, <tt>weak</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000298
Chris Lattner79c3fe12003-10-02 04:57:28 +0000299 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
300 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
301 <tt>vector_size</tt>, <tt>dllimport</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000302 <tt>dllexport</tt>, all target specific attributes.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000303
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000304 <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 +0000305 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000306 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000307
308 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
309 all target specific attributes.</li>
310
Chris Lattner79c3fe12003-10-02 04:57:28 +0000311 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
312 Other built-in functions.<br>
313 We support all builtins which have a C language equivalent (e.g.,
314 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
315 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Chris Lattnerceebeb62004-06-18 06:26:29 +0000316 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
317 (currently ignored). We also support builtins for ISO C99 floating
Chris Lattner7939b782005-05-07 02:21:21 +0000318 point comparison macros (e.g., <tt>__builtin_islessequal</tt>),
319 <tt>__builtin_prefetch</tt>, <tt>__builtin_popcount[ll]</tt>,
320 <tt>__builtin_clz[ll]</tt>, and <tt>__builtin_ctz[ll]</tt>.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000321 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000322
Misha Brukman500bc302003-11-22 00:38:41 +0000323 <p>The following extensions <b>are</b> known to be supported:</p>
324
Chris Lattner79c3fe12003-10-02 04:57:28 +0000325 <ol>
Chris Lattner7fe97dd2004-03-16 08:54:07 +0000326 <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 +0000327 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
328 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Typeof.html#Typeof">Typeof</a>: <code>typeof</code>: referring to the type of an expression.</li>
Tanya Lattnerca26c3e2004-06-22 03:48:17 +0000329 <li><a href="http://gcc.gnu.org/onlinedocs/gcc-3.4.0/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000330 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
331 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
332 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
333 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
334 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
335 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
336 <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>
337 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
338 <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 +0000339 <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 +0000340 <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 +0000341 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
342or arrays as values.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000343 <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 +0000344 <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 +0000345 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
346 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
347 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
Tanya Lattner78537e42004-12-08 18:29:38 +0000348 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Comments.html#C_002b_002b-Comments">C++ Comments</a>: C++ comments are recognized.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000349 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
350 <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>
351 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
352 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
353 <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>
354 <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>
355 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Names.html#Function%20Names">Function Names</a>: Printable strings which are the name of the current function.</li>
Chris Lattner25795bc2004-02-14 04:08:29 +0000356 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Return-Address.html#Return%20Address">Return Address</a>: Getting the return or frame address of a function.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000357 <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>
358 <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 +0000359 </ol></li>
360
361</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000362
Misha Brukman500bc302003-11-22 00:38:41 +0000363<p>If you run into GCC extensions which have not been included in any of these
364lists, please let us know (also including whether or not they work).</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000365
Misha Brukman500bc302003-11-22 00:38:41 +0000366</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000367
Misha Brukman500bc302003-11-22 00:38:41 +0000368<!-- ======================================================================= -->
369<div class="doc_subsection">
370 <a name="c++-fe">Known problems with the C++ front-end</a>
371</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000372
Misha Brukman500bc302003-11-22 00:38:41 +0000373<div class="doc_text">
374
Reid Spencere09ca642004-12-07 08:39:08 +0000375<p>For this release, the C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000376tested and works for a number of non-trivial programs, including LLVM
377itself.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000378
379</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000380
381<!-- _______________________________________________________________________ -->
Chris Lattner3a51be12004-02-14 04:12:41 +0000382<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000383
Misha Brukman500bc302003-11-22 00:38:41 +0000384<div class="doc_text">
Chris Lattner79c3fe12003-10-02 04:57:28 +0000385
Misha Brukman500bc302003-11-22 00:38:41 +0000386<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000387<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
John Criswelld000e1d2003-12-18 16:43:17 +0000388 front-end</a>.</li>
Chris Lattner7962f712004-07-17 02:04:41 +0000389
Chris Lattnerd5713882004-08-02 20:28:44 +0000390</ul>
391
Misha Brukman500bc302003-11-22 00:38:41 +0000392</div>
393
394<!-- _______________________________________________________________________ -->
395<div class="doc_subsubsection">
396 Notes
397</div>
398
399<div class="doc_text">
400
401<ul>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000402
Chris Lattner79c3fe12003-10-02 04:57:28 +0000403<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
404parser is significantly more standards compliant (and picky) than prior GCC
405versions. For more information, see the C++ section of the <a
Chris Lattner9e848092003-12-12 04:25:33 +0000406href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000407
408<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
Chris Lattner19092612003-10-02 16:38:05 +0000409 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000410 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswelld000e1d2003-12-18 16:43:17 +0000411 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman500bc302003-11-22 00:38:41 +0000412 better than most compilers).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000413
Chris Lattner19092612003-10-02 16:38:05 +0000414<li>The LLVM C++ front-end follows the <a
415 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
416 This document, which is not Itanium specific, specifies a standard for name
417 mangling, class layout, v-table layout, RTTI formats, and other C++
418 representation issues. Because we use this API, code generated by the LLVM
419 compilers should be binary compatible with machine code generated by other
420 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
421 <i>However</i>, the exception handling mechanism used by LLVM is very
422 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman500bc302003-11-22 00:38:41 +0000423 interact correctly</b>. </li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000424
Misha Brukman500bc302003-11-22 00:38:41 +0000425</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000426
Misha Brukman500bc302003-11-22 00:38:41 +0000427</div>
428
429<!-- ======================================================================= -->
430<div class="doc_subsection">
Misha Brukman500bc302003-11-22 00:38:41 +0000431 <a name="c-be">Known problems with the C back-end</a>
432</div>
433
434<div class="doc_text">
435
436<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000437
438<li>The C back-end produces code that violates the ANSI C Type-Based Alias
439Analysis rules. As such, special options may be necessary to compile the code
440(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
Misha Brukman500bc302003-11-22 00:38:41 +0000441problem probably cannot be fixed.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000442
Chris Lattner2855ecd2003-11-04 20:06:53 +0000443<li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
Chris Lattner2af46052003-10-24 04:03:19 +0000444supported</a>. This should not affect LLVM produced by the C or C++
Misha Brukman500bc302003-11-22 00:38:41 +0000445frontends.</li>
Chris Lattner2af46052003-10-24 04:03:19 +0000446
Misha Brukman500bc302003-11-22 00:38:41 +0000447</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000448
Misha Brukman500bc302003-11-22 00:38:41 +0000449</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000450
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000451<!-- ======================================================================= -->
452<div class="doc_subsection">
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000453 <a name="x86-be">Known problems with the X86 back-end</a>
454</div>
455
456<div class="doc_text">
457
458<ul>
John Criswell8bfe6a72005-05-18 19:43:33 +0000459<li><a href="http://llvm.cs.uiuc.edu/PR566">Memory Mapped I/O Intrinsics do not fence memory</a></li>
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000460</ul>
461
462</div>
463
464<!-- ======================================================================= -->
465<div class="doc_subsection">
466 <a name="ppc-be">Known problems with the PowerPC back-end</a>
467</div>
468
469<div class="doc_text">
470
471<ul>
472<li>None yet</li>
473</ul>
474
475</div>
476
477<!-- ======================================================================= -->
478<div class="doc_subsection">
479 <a name="sparcv9-be">Known problems with the SparcV9 back-end</a>
480</div>
481
482<div class="doc_text">
483
484<ul>
485<li><a href="http://llvm.cs.uiuc.edu/PR60">[sparcv9] SparcV9 backend miscompiles
486several programs in the LLVM test suite</a></li>
487</ul>
488
489</div>
490
491<!-- ======================================================================= -->
492<div class="doc_subsection">
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000493 <a name="alpha-be">Known problems with the Alpha back-end</a>
494</div>
495
496<div class="doc_text">
497
498<ul>
499
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000500<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
501appropriate nops inserted to ensure restartability.</li>
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000502
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000503<li>Defining vararg functions is not supported (but calling them is ok).</li>
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000504
Andrew Lenharth01f40b32005-05-14 17:43:00 +0000505<li>Due to the vararg problems, C++ exceptions do not work. Small changes are required to the CFE (which break correctness in the exception handler) to compile the exception handling library (and thus the C++ standard library).</li>
506
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000507</ul>
508
509</div>
510
Duraid Madina2e36d6e2005-05-14 05:48:13 +0000511<!-- ======================================================================= -->
512<div class="doc_subsection">
513 <a name="ia64-be">Known problems with the IA64 back-end</a>
514</div>
515
516<div class="doc_text">
517
518<ul>
519
520<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
521made where the argument is not 16-byte aligned, as required on IA64. (Strictly
522speaking this is not a bug in the IA64 back-end; it will also be encountered
523when building C++ programs using the C back-end.)</li>
524
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000525<li>The C++ front-end does not use <a href="http://llvm.cs.uiuc.edu/PR406">IA64
526ABI compliant layout of v-tables</a>. In particular, it just stores function
527pointers instead of function descriptors in the vtable. This bug prevents
528mixing C++ code compiled with LLVM with C++ objects compiled by other C++
529compilers.</li>
Duraid Madina2e36d6e2005-05-14 05:48:13 +0000530
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000531<li>There are a few ABI violations which will lead to problems when mixing LLVM
532output with code built with other compilers, particularly for floating-point
533programs.</li>
534
535<li>Defining vararg functions is not supported (but calling them is ok).</li>
Duraid Madina2e36d6e2005-05-14 05:48:13 +0000536
537</ul>
538
539</div>
540
Chris Lattner98a493c2005-05-15 16:01:20 +0000541<!-- ======================================================================= -->
542<div class="doc_subsection">
543 <a name="sparcv8">Known problems with the SPARC-V8 back-end</a>
544</div>
545
546<div class="doc_text">
547
548<ul>
549<li>Many features are still missing (e.g. support for 64-bit integer
550arithmetic).</li>
551
552<li>This backend needs to be updated to use the SelectionDAG instruction
553selection framework.</li>
554</ul>
555
556</div>
557
Chris Lattner79c3fe12003-10-02 04:57:28 +0000558<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000559<div class="doc_section">
560 <a name="additionalinfo">Additional Information</a>
561</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000562<!-- *********************************************************************** -->
563
Misha Brukman500bc302003-11-22 00:38:41 +0000564<div class="doc_text">
565
Chris Lattner416db102005-05-16 17:13:10 +0000566<p>A wide variety of additional information is available on the <a
567href="http://llvm.cs.uiuc.edu">LLVM web page</a>, including <a
568href="http://llvm.cs.uiuc.edu/docs/">documentation</a> and <a
569href="http://llvm.cs.uiuc.edu/pubs/">publications describing algorithms and
Misha Brukman109d9e82005-03-30 19:14:24 +0000570components implemented in LLVM</a>. The web page also contains versions of the
571API documentation which is up-to-date with the CVS version of the source code.
572You can access versions of these documents specific to this release by going
573into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000574
Misha Brukman500bc302003-11-22 00:38:41 +0000575<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattner416db102005-05-16 17:13:10 +0000576us via the <a href="http://llvm.cs.uiuc.edu/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000577lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000578
Misha Brukman500bc302003-11-22 00:38:41 +0000579</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000580
581<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000582
Misha Brukman500bc302003-11-22 00:38:41 +0000583<hr>
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