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Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]7 <title>LLVM 2.2 Release Notes</title>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]8</head>
9<body>
10
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]11<div class="doc_title">LLVM 2.2 Release Notes</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]12
13<ol>
14 <li><a href="#intro">Introduction</a></li>
15 <li><a href="#whatsnew">What's New?</a></li>
16 <li><a href="GettingStarted.html">Installation Instructions</a></li>
17 <li><a href="#portability">Portability and Supported Platforms</a></li>
18 <li><a href="#knownproblems">Known Problems</a>
19 <li><a href="#additionalinfo">Additional Information</a></li>
20</ol>
21
22<div class="doc_author">
23 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
24</div>
25
26<!-- *********************************************************************** -->
27<div class="doc_section">
28 <a name="intro">Introduction</a>
29</div>
30<!-- *********************************************************************** -->
31
32<div class="doc_text">
33
34<p>This document contains the release notes for the LLVM compiler
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]35infrastructure, release 2.2. Here we describe the status of LLVM, including
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]36major improvements from the previous release and any known problems. All LLVM
37releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
38releases web site</a>.</p>
39
40<p>For more information about LLVM, including information about the latest
41release, please check out the <a href="http://llvm.org/">main LLVM
42web site</a>. If you have questions or comments, the <a
43href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
44list</a> is a good place to send them.</p>
45
46<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]47main LLVM web page, this document applies to the <i>next</i> release, not the
48current one. To see the release notes for a specific releases, please see the
49<a href="http://llvm.org/releases/">releases page</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]50
51</div>
52
53<!-- *********************************************************************** -->
54<div class="doc_section">
55 <a name="whatsnew">What's New?</a>
56</div>
57<!-- *********************************************************************** -->
58
59<div class="doc_text">
60
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]61<p>This is the thirteenth public release of the LLVM Compiler Infrastructure.
62It includes many features and refinements from LLVM 2.1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]63
64</div>
65
66<!--=========================================================================-->
67<div class="doc_subsection">
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]68<a name="frontends">llvm-gcc 4.0, llvm-gcc 4.2, and clang</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]69</div>
70
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]71<div class="doc_text">
72
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]73<p>LLVM 2.2 fully supports both the llvm-gcc 4.0 and llvm-gcc 4.2 front-ends (in
74LLVM 2.1, llvm-gcc 4.2 was beta). Since LLVM 2.1, the llvm-gcc 4.2 front-end
75has made leaps and bounds and is now at least as good as 4.0 in virtually every
76area, and is better in several areas (for example, exception handling
77correctness). We strongly recommend that you migrate from llvm-gcc 4.0 to
78llvm-gcc 4.2 in this release cycle because <b>LLVM 2.2 is the last release
79that will support llvm-gcc 4.0</b>: LLVM 2.3 will only support the llvm-gcc
804.2 front-end.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]81
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]82<p>The <a href="http://clang.llvm.org/">clang project</a> is an effort
83to build a set of new front-end technology for the LLVM optimizer and code
84generator. Currently, its C and Objective-C support is maturing nicely, and it
85has advanced source-to-source analysis and transformation capabilities. If you
86are interested in building source-level tools for C and Objective-C (and
87eventually C++), you should take a look. However, note that clang is not an
88official part of the LLVM 2.2 release. If you are interested in this project,
89please see the web site and check it out from SVN head.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]90
91</div>
92
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]93<!--=========================================================================-->
94<div class="doc_subsection">
95<a name="optimizer">Optimizer Improvements</a>
96</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]97
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]98<div class="doc_text">
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]99
Chris Lattner7d2b1102007-09-26 05:44:21 +0000[diff] [blame]100<p>Some of the most noticable feature improvements this release have been in the
101optimizer, speeding it up and making it more aggressive. For example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]102
103<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]104
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]105<li>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]106
107</ul>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]108
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]109</div>
110
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]111<!--=========================================================================-->
112<div class="doc_subsection">
113<a name="codegen">Code Generator Improvements</a>
114</div>
115
116<div class="doc_text">
117
Chris Lattner7d2b1102007-09-26 05:44:21 +0000[diff] [blame]118<p>One of the main focuses of this release was performance tuning and bug
119 fixing. In addition to these, several new major changes occurred:</p>
120
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]121<ul>
122
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]123<li>.</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]124
125</ul>
126
127</div>
128
129
130<!--=========================================================================-->
131<div class="doc_subsection">
132<a name="targetspecific">Target Specific Improvements</a>
133</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]134
135<div class="doc_text">
136<p>New features include:
137</p>
138
139<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]140<li>.</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]141</ul>
142
143</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]144
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]145
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]146<!--=========================================================================-->
147<div class="doc_subsection">
148<a name="llvmgccimprovements">llvm-gcc Improvements</a>
149</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]150
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]151<div class="doc_text">
152<p>New features include:
153</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]154
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]155<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]156<li>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]157</ul>
158
159</div>
160
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]161
162<!--=========================================================================-->
163<div class="doc_subsection">
164<a name="coreimprovements">LLVM Core Improvements</a>
165</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]166
167<div class="doc_text">
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]168<p>New features include:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]169</p>
170
171<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]172<li>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]173</ul>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]174
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]175</div>
176
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]177<!--=========================================================================-->
178<div class="doc_subsection">
179<a name="otherimprovements">Other Improvements</a>
180</div>
181
182<div class="doc_text">
183<p>New features include:
184</p>
185
186<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]187<li>.</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]188</ul>
189
190</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]191
192<!-- *********************************************************************** -->
193<div class="doc_section">
194 <a name="portability">Portability and Supported Platforms</a>
195</div>
196<!-- *********************************************************************** -->
197
198<div class="doc_text">
199
200<p>LLVM is known to work on the following platforms:</p>
201
202<ul>
203<li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
204 (and probably other unix-like systems).</li>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]205<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]206 64-bit modes.</li>
207<li>Intel and AMD machines running on Win32 using MinGW libraries (native)</li>
208<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
209 support is available for native builds with Visual C++).</li>
210<li>Sun UltraSPARC workstations running Solaris 8.</li>
211<li>Alpha-based machines running Debian GNU/Linux.</li>
212<li>Itanium-based machines running Linux and HP-UX.</li>
213</ul>
214
215<p>The core LLVM infrastructure uses
216<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
217to the machine and operating system on which it is built. However, minor
218porting may be required to get LLVM to work on new platforms. We welcome your
219portability patches and reports of successful builds or error messages.</p>
220
221</div>
222
223<!-- *********************************************************************** -->
224<div class="doc_section">
225 <a name="knownproblems">Known Problems</a>
226</div>
227<!-- *********************************************************************** -->
228
229<div class="doc_text">
230
231<p>This section contains all known problems with the LLVM system, listed by
232component. As new problems are discovered, they will be added to these
233sections. If you run into a problem, please check the <a
234href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
235there isn't already one.</p>
236
237</div>
238
239<!-- ======================================================================= -->
240<div class="doc_subsection">
241 <a name="experimental">Experimental features included with this release</a>
242</div>
243
244<div class="doc_text">
245
246<p>The following components of this LLVM release are either untested, known to
247be broken or unreliable, or are in early development. These components should
248not be relied on, and bugs should not be filed against them, but they may be
249useful to some people. In particular, if you would like to work on one of these
250components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
251
252<ul>
Bill Wendlingc3aa3502007-09-25 20:45:10 +0000[diff] [blame]253<li>The <tt>-cee</tt> pass is known to be buggy, and may be removed in a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]254 future release.</li>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]255<li>The MSIL, IA64, Alpha, and MIPS backends are experimental.</li>
256<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
257 value for this option.</li>
258<li>The llvmc tool is not supported.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]259</ul>
260
261</div>
262
263<!-- ======================================================================= -->
264<div class="doc_subsection">
265 <a name="x86-be">Known problems with the X86 back-end</a>
266</div>
267
268<div class="doc_text">
269
270<ul>
271<li>The X86 backend does not yet support <a href="http://llvm.org/PR879">inline
272 assembly that uses the X86 floating point stack</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]273<li>The X86 backend occasionally has <a href="http://llvm.org/PR1649">alignment
274 problems</a> on operating systems that don't require 16-byte stack alignment
275 (including most non-darwin OS's like linux).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]276</ul>
277
278</div>
279
280<!-- ======================================================================= -->
281<div class="doc_subsection">
282 <a name="ppc-be">Known problems with the PowerPC back-end</a>
283</div>
284
285<div class="doc_text">
286
287<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]288<li>The Linux PPC32/ABI support needs testing for the interpreter and static
289compilation, and lacks support for debug information.</li>
290</ul>
291
292</div>
293
294<!-- ======================================================================= -->
295<div class="doc_subsection">
296 <a name="arm-be">Known problems with the ARM back-end</a>
297</div>
298
299<div class="doc_text">
300
301<ul>
302<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]303processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]304results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
305<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
306</li>
307<li>There is a bug in QEMU-ARM (<= 0.9.0) which causes it to incorrectly execute
308programs compiled with LLVM. Please use more recent versions of QEMU.</li>
309</ul>
310
311</div>
312
313<!-- ======================================================================= -->
314<div class="doc_subsection">
315 <a name="sparc-be">Known problems with the SPARC back-end</a>
316</div>
317
318<div class="doc_text">
319
320<ul>
321<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
322 support the 64-bit SPARC ABI (-m64).</li>
323</ul>
324
325</div>
326
327<!-- ======================================================================= -->
328<div class="doc_subsection">
329 <a name="alpha-be">Known problems with the Alpha back-end</a>
330</div>
331
332<div class="doc_text">
333
334<ul>
335
336<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
337appropriate nops inserted to ensure restartability.</li>
338
339</ul>
340</div>
341
342<!-- ======================================================================= -->
343<div class="doc_subsection">
344 <a name="ia64-be">Known problems with the IA64 back-end</a>
345</div>
346
347<div class="doc_text">
348
349<ul>
350
351<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
352made where the argument is not 16-byte aligned, as required on IA64. (Strictly
353speaking this is not a bug in the IA64 back-end; it will also be encountered
354when building C++ programs using the C back-end.)</li>
355
356<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
357ABI compliant layout of v-tables</a>. In particular, it just stores function
358pointers instead of function descriptors in the vtable. This bug prevents
359mixing C++ code compiled with LLVM with C++ objects compiled by other C++
360compilers.</li>
361
362<li>There are a few ABI violations which will lead to problems when mixing LLVM
363output with code built with other compilers, particularly for floating-point
364programs.</li>
365
366<li>Defining vararg functions is not supported (but calling them is ok).</li>
367
368<li>The Itanium backend has bitrotted somewhat.</li>
369</ul>
370
371</div>
372
373<!-- ======================================================================= -->
374<div class="doc_subsection">
375 <a name="c-be">Known problems with the C back-end</a>
376</div>
377
378<div class="doc_text">
379
380<ul>
381<li><a href="http://llvm.org/PR802">The C backend does not support inline
382 assembly code</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]383<li><a href="http://llvm.org/PR1126">The C backend does not support vectors
384 yet</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]385<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
386 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
387 C++ code compiled with LLC or native compilers.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]388</ul>
389
390</div>
391
392
393<!-- ======================================================================= -->
394<div class="doc_subsection">
395 <a name="c-fe">Known problems with the C front-end</a>
396</div>
397
398<!-- _______________________________________________________________________ -->
399<div class="doc_subsubsection">Bugs</div>
400
401<div class="doc_text">
402
403<p>llvm-gcc4 does not currently support <a href="http://llvm.org/PR869">Link-Time
404Optimization</a> on most platforms "out-of-the-box". Please inquire on the
405llvmdev mailing list if you are interested.</p>
406
407</div>
408
409<!-- _______________________________________________________________________ -->
410<div class="doc_subsubsection">
411 Notes
412</div>
413
414<div class="doc_text">
415<ul>
416
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]417<li><p>llvm-gcc does <b>not</b> support <tt>__builtin_apply</tt> yet.
418 See <a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</p>
419</li>
420
421<li><p>llvm-gcc <b>partially</b> supports these GCC extensions:</p>
422 <ol>
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]423 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html#Nested%20Functions">Nested Functions</a>:
424
425 As in Algol and Pascal, lexical scoping of functions.
426 Nested functions are supported, but llvm-gcc does not support
Duncan Sands6b761d32007-09-26 16:24:52 +0000[diff] [blame]427 taking the address of a nested function (except on the X86-32 target)
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]428 or non-local gotos.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]429
430 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
431
432 Declaring that functions have no side effects or that they can never
433 return.<br>
434
Anton Korobeynikov08dcc472007-11-16 11:12:01 +0000[diff] [blame]435 <b>Supported:</b> <tt>alias</tt>, <tt>always_inline</tt>, <tt>cdecl</tt>,
436 <tt>const</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]437 <tt>deprecated</tt>, <tt>fastcall</tt>, <tt>format</tt>,
Anton Korobeynikov08dcc472007-11-16 11:12:01 +0000[diff] [blame]438 <tt>format_arg</tt>, <tt>non_null</tt>, <tt>noinline</tt>,
439 <tt>noreturn</tt>, <tt>pure</tt>, <tt>regparm</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]440 <tt>section</tt>, <tt>stdcall</tt>, <tt>unused</tt>, <tt>used</tt>,
441 <tt>visibility</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
442
Anton Korobeynikov08dcc472007-11-16 11:12:01 +0000[diff] [blame]443 <b>Ignored:</b> <tt>nothrow</tt>, <tt>malloc</tt>,
444 <tt>no_instrument_function</tt></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]445 </ol>
446</li>
447
448<li><p>llvm-gcc supports the vast majority of GCC extensions, including:</p>
449
450 <ol>
451 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
452 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
453 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
454 Other built-in functions.</li>
455 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
456 Specifying attributes of variables.</li>
457 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.</li>
458 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
459 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
460 Arrays whose length is computed at run time.</li>
461 <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>
462 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
463 <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>
464 <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>
465 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
466 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
467 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
468 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
469 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
470 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
471 <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>
472 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
473 <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>
474 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
475 <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>
476 <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>
477 <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>
478 <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>
479 <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>
480 <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>
481 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
482 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
483or arrays as values.</li>
484 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.</li>
485 <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>
486 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
487 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
488 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
489 <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>
490 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
491 <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>
492 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
493 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
494 <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>
495 <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>
496 <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>
497 <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>
498 <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>
499 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.</li>
500 </ol></li>
501
502</ul>
503
504<p>If you run into GCC extensions which have not been included in any of these
505lists, please let us know (also including whether or not they work).</p>
506
507</div>
508
509<!-- ======================================================================= -->
510<div class="doc_subsection">
511 <a name="c++-fe">Known problems with the C++ front-end</a>
512</div>
513
514<div class="doc_text">
515
516<p>The C++ front-end is considered to be fully
517tested and works for a number of non-trivial programs, including LLVM
518itself, Qt, Mozilla, etc.</p>
519
520<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame^]521<li>Exception handling only works well on the X86 and PowerPC targets.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]522</ul>
523
524</div>
525
526
527
528<!-- *********************************************************************** -->
529<div class="doc_section">
530 <a name="additionalinfo">Additional Information</a>
531</div>
532<!-- *********************************************************************** -->
533
534<div class="doc_text">
535
536<p>A wide variety of additional information is available on the <a
537href="http://llvm.org">LLVM web page</a>, in particular in the <a
538href="http://llvm.org/docs/">documentation</a> section. The web page also
539contains versions of the API documentation which is up-to-date with the
540Subversion version of the source code.
541You can access versions of these documents specific to this release by going
542into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
543
544<p>If you have any questions or comments about LLVM, please feel free to contact
545us via the <a href="http://llvm.org/docs/#maillist"> mailing
546lists</a>.</p>
547
548</div>
549
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