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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 Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame^]82<p>The <a href="http://clang.llvm.org/">clang project</a> is an effort to build
83a set of new 'llvm native' front-end technologies for the LLVM optimizer
84and code generator. Currently, its C and Objective-C support is maturing
85nicely, and it has advanced source-to-source analysis and transformation
86capabilities. If you are interested in building source-level tools for C and
87Objective-C (and eventually C++), you should take a look. However, note that
88clang is not an official part of the LLVM 2.2 release. If you are interested in
89this project, please see the web site.</p>
90
91</div>
92
93<!--=========================================================================-->
94<div class="doc_subsection">
95<a name="majorfeatures">Major New Features</a>
96</div>
97
98<div class="doc_text">
99
100<p>Dale contributed full support for long double on x86/x86-64 (where it is 80
101bits) and on Darwin PPC/PPC64 (where it is 128 bits).</p>
102
103<p>Ada, gfortran</p>
104
105<p>
106debug improvements -O0
107EH.
108
109Gordon: GC Revamp. docs/GarbageCollection.html
110
111Kaleidescope: docs/tutorial
112
113Gordon: C and Ocaml Bindings
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]114
115</div>
116
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]117<!--=========================================================================-->
118<div class="doc_subsection">
119<a name="optimizer">Optimizer Improvements</a>
120</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]121
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]122<div class="doc_text">
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]123
Chris Lattner7d2b1102007-09-26 05:44:21 +0000[diff] [blame]124<p>Some of the most noticable feature improvements this release have been in the
125optimizer, speeding it up and making it more aggressive. For example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]126
127<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]128
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame^]129<li>Daniel Berlin and (?) rewrote Andersen's alias analysis (which is not
130enabled by default) to be several orders of magnitude faster, implmented Offline
131Variable Substitution.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]132
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame^]133
134Devang: LoopIndexSplit is enabled by default.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]135</ul>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]136
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]137</div>
138
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]139<!--=========================================================================-->
140<div class="doc_subsection">
141<a name="codegen">Code Generator Improvements</a>
142</div>
143
144<div class="doc_text">
145
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame^]146<p>foci of this release was performance tuning and bug
Chris Lattner7d2b1102007-09-26 05:44:21 +0000[diff] [blame]147 fixing. In addition to these, several new major changes occurred:</p>
148
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]149<ul>
150
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame^]151<li>Owen contributed Machine Loop info, domintors, etc.</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]152
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame^]153<li>Dan added support for emitting debug information with .file and .loc on
154targets that support it</li>
155
156<li>Evan physical register dependencies in the BURR scheduler</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]157</ul>
158
159</div>
160
161
162<!--=========================================================================-->
163<div class="doc_subsection">
164<a name="targetspecific">Target Specific Improvements</a>
165</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]166
167<div class="doc_text">
168<p>New features include:
169</p>
170
171<ul>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame^]172<li>Evan X86 now models EFLAGS in instructions.</li>
173<li>Evan: If conversion on by default for ARM.</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]174</ul>
175
176</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]177
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]178
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]179<!--=========================================================================-->
180<div class="doc_subsection">
181<a name="llvmgccimprovements">llvm-gcc Improvements</a>
182</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]183
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]184<div class="doc_text">
185<p>New features include:
186</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]187
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]188<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]189<li>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]190</ul>
191
192</div>
193
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]194
195<!--=========================================================================-->
196<div class="doc_subsection">
197<a name="coreimprovements">LLVM Core Improvements</a>
198</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]199
200<div class="doc_text">
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]201<p>New features include:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]202</p>
203
204<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]205<li>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]206</ul>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]207
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]208</div>
209
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]210<!--=========================================================================-->
211<div class="doc_subsection">
212<a name="otherimprovements">Other Improvements</a>
213</div>
214
215<div class="doc_text">
216<p>New features include:
217</p>
218
219<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]220<li>.</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]221</ul>
222
223</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]224
225<!-- *********************************************************************** -->
226<div class="doc_section">
227 <a name="portability">Portability and Supported Platforms</a>
228</div>
229<!-- *********************************************************************** -->
230
231<div class="doc_text">
232
233<p>LLVM is known to work on the following platforms:</p>
234
235<ul>
236<li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
237 (and probably other unix-like systems).</li>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]238<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]239 64-bit modes.</li>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame^]240<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]241<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
242 support is available for native builds with Visual C++).</li>
243<li>Sun UltraSPARC workstations running Solaris 8.</li>
244<li>Alpha-based machines running Debian GNU/Linux.</li>
245<li>Itanium-based machines running Linux and HP-UX.</li>
246</ul>
247
248<p>The core LLVM infrastructure uses
249<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
250to the machine and operating system on which it is built. However, minor
251porting may be required to get LLVM to work on new platforms. We welcome your
252portability patches and reports of successful builds or error messages.</p>
253
254</div>
255
256<!-- *********************************************************************** -->
257<div class="doc_section">
258 <a name="knownproblems">Known Problems</a>
259</div>
260<!-- *********************************************************************** -->
261
262<div class="doc_text">
263
264<p>This section contains all known problems with the LLVM system, listed by
265component. As new problems are discovered, they will be added to these
266sections. If you run into a problem, please check the <a
267href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
268there isn't already one.</p>
269
270</div>
271
272<!-- ======================================================================= -->
273<div class="doc_subsection">
274 <a name="experimental">Experimental features included with this release</a>
275</div>
276
277<div class="doc_text">
278
279<p>The following components of this LLVM release are either untested, known to
280be broken or unreliable, or are in early development. These components should
281not be relied on, and bugs should not be filed against them, but they may be
282useful to some people. In particular, if you would like to work on one of these
283components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
284
285<ul>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame^]286<li>The <tt>-cee</tt> pass is known to be buggy and will be removed in
287 LLVM 2.3.</li>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]288<li>The MSIL, IA64, Alpha, and MIPS backends are experimental.</li>
289<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
290 value for this option.</li>
291<li>The llvmc tool is not supported.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]292</ul>
293
294</div>
295
296<!-- ======================================================================= -->
297<div class="doc_subsection">
298 <a name="x86-be">Known problems with the X86 back-end</a>
299</div>
300
301<div class="doc_text">
302
303<ul>
304<li>The X86 backend does not yet support <a href="http://llvm.org/PR879">inline
305 assembly that uses the X86 floating point stack</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]306<li>The X86 backend occasionally has <a href="http://llvm.org/PR1649">alignment
307 problems</a> on operating systems that don't require 16-byte stack alignment
308 (including most non-darwin OS's like linux).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]309</ul>
310
311</div>
312
313<!-- ======================================================================= -->
314<div class="doc_subsection">
315 <a name="ppc-be">Known problems with the PowerPC back-end</a>
316</div>
317
318<div class="doc_text">
319
320<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]321<li>The Linux PPC32/ABI support needs testing for the interpreter and static
322compilation, and lacks support for debug information.</li>
323</ul>
324
325</div>
326
327<!-- ======================================================================= -->
328<div class="doc_subsection">
329 <a name="arm-be">Known problems with the ARM back-end</a>
330</div>
331
332<div class="doc_text">
333
334<ul>
335<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]336processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]337results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
338<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
339</li>
340<li>There is a bug in QEMU-ARM (<= 0.9.0) which causes it to incorrectly execute
341programs compiled with LLVM. Please use more recent versions of QEMU.</li>
342</ul>
343
344</div>
345
346<!-- ======================================================================= -->
347<div class="doc_subsection">
348 <a name="sparc-be">Known problems with the SPARC back-end</a>
349</div>
350
351<div class="doc_text">
352
353<ul>
354<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
355 support the 64-bit SPARC ABI (-m64).</li>
356</ul>
357
358</div>
359
360<!-- ======================================================================= -->
361<div class="doc_subsection">
362 <a name="alpha-be">Known problems with the Alpha back-end</a>
363</div>
364
365<div class="doc_text">
366
367<ul>
368
369<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
370appropriate nops inserted to ensure restartability.</li>
371
372</ul>
373</div>
374
375<!-- ======================================================================= -->
376<div class="doc_subsection">
377 <a name="ia64-be">Known problems with the IA64 back-end</a>
378</div>
379
380<div class="doc_text">
381
382<ul>
383
384<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
385made where the argument is not 16-byte aligned, as required on IA64. (Strictly
386speaking this is not a bug in the IA64 back-end; it will also be encountered
387when building C++ programs using the C back-end.)</li>
388
389<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
390ABI compliant layout of v-tables</a>. In particular, it just stores function
391pointers instead of function descriptors in the vtable. This bug prevents
392mixing C++ code compiled with LLVM with C++ objects compiled by other C++
393compilers.</li>
394
395<li>There are a few ABI violations which will lead to problems when mixing LLVM
396output with code built with other compilers, particularly for floating-point
397programs.</li>
398
399<li>Defining vararg functions is not supported (but calling them is ok).</li>
400
401<li>The Itanium backend has bitrotted somewhat.</li>
402</ul>
403
404</div>
405
406<!-- ======================================================================= -->
407<div class="doc_subsection">
408 <a name="c-be">Known problems with the C back-end</a>
409</div>
410
411<div class="doc_text">
412
413<ul>
414<li><a href="http://llvm.org/PR802">The C backend does not support inline
415 assembly code</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]416<li><a href="http://llvm.org/PR1126">The C backend does not support vectors
417 yet</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]418<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
419 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
420 C++ code compiled with LLC or native compilers.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]421</ul>
422
423</div>
424
425
426<!-- ======================================================================= -->
427<div class="doc_subsection">
428 <a name="c-fe">Known problems with the C front-end</a>
429</div>
430
431<!-- _______________________________________________________________________ -->
432<div class="doc_subsubsection">Bugs</div>
433
434<div class="doc_text">
435
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame^]436<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
437Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]438llvmdev mailing list if you are interested.</p>
439
440</div>
441
442<!-- _______________________________________________________________________ -->
443<div class="doc_subsubsection">
444 Notes
445</div>
446
447<div class="doc_text">
448<ul>
449
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]450<li><p>llvm-gcc does <b>not</b> support <tt>__builtin_apply</tt> yet.
451 See <a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</p>
452</li>
453
454<li><p>llvm-gcc <b>partially</b> supports these GCC extensions:</p>
455 <ol>
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]456 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html#Nested%20Functions">Nested Functions</a>:
457
458 As in Algol and Pascal, lexical scoping of functions.
459 Nested functions are supported, but llvm-gcc does not support
Duncan Sands6b761d32007-09-26 16:24:52 +0000[diff] [blame]460 taking the address of a nested function (except on the X86-32 target)
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]461 or non-local gotos.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]462
463 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
464
465 Declaring that functions have no side effects or that they can never
466 return.<br>
467
Anton Korobeynikov08dcc472007-11-16 11:12:01 +0000[diff] [blame]468 <b>Supported:</b> <tt>alias</tt>, <tt>always_inline</tt>, <tt>cdecl</tt>,
469 <tt>const</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]470 <tt>deprecated</tt>, <tt>fastcall</tt>, <tt>format</tt>,
Anton Korobeynikov08dcc472007-11-16 11:12:01 +0000[diff] [blame]471 <tt>format_arg</tt>, <tt>non_null</tt>, <tt>noinline</tt>,
472 <tt>noreturn</tt>, <tt>pure</tt>, <tt>regparm</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]473 <tt>section</tt>, <tt>stdcall</tt>, <tt>unused</tt>, <tt>used</tt>,
474 <tt>visibility</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
475
Anton Korobeynikov08dcc472007-11-16 11:12:01 +0000[diff] [blame]476 <b>Ignored:</b> <tt>nothrow</tt>, <tt>malloc</tt>,
477 <tt>no_instrument_function</tt></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]478 </ol>
479</li>
480
481<li><p>llvm-gcc supports the vast majority of GCC extensions, including:</p>
482
483 <ol>
484 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
485 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
486 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
487 Other built-in functions.</li>
488 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
489 Specifying attributes of variables.</li>
490 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.</li>
491 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
492 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
493 Arrays whose length is computed at run time.</li>
494 <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>
495 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
496 <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>
497 <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>
498 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
499 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
500 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
501 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
502 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
503 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
504 <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>
505 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
506 <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>
507 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
508 <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>
509 <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>
510 <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>
511 <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>
512 <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>
513 <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>
514 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
515 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
516or arrays as values.</li>
517 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.</li>
518 <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>
519 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
520 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
521 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
522 <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>
523 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
524 <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>
525 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
526 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
527 <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>
528 <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>
529 <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>
530 <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>
531 <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>
532 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.</li>
533 </ol></li>
534
535</ul>
536
537<p>If you run into GCC extensions which have not been included in any of these
538lists, please let us know (also including whether or not they work).</p>
539
540</div>
541
542<!-- ======================================================================= -->
543<div class="doc_subsection">
544 <a name="c++-fe">Known problems with the C++ front-end</a>
545</div>
546
547<div class="doc_text">
548
549<p>The C++ front-end is considered to be fully
550tested and works for a number of non-trivial programs, including LLVM
551itself, Qt, Mozilla, etc.</p>
552
553<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]554<li>Exception handling only works well on the X86 and PowerPC targets.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]555</ul>
556
557</div>
558
559
560
561<!-- *********************************************************************** -->
562<div class="doc_section">
563 <a name="additionalinfo">Additional Information</a>
564</div>
565<!-- *********************************************************************** -->
566
567<div class="doc_text">
568
569<p>A wide variety of additional information is available on the <a
570href="http://llvm.org">LLVM web page</a>, in particular in the <a
571href="http://llvm.org/docs/">documentation</a> section. The web page also
572contains versions of the API documentation which is up-to-date with the
573Subversion version of the source code.
574You can access versions of these documents specific to this release by going
575into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
576
577<p>If you have any questions or comments about LLVM, please feel free to contact
578us via the <a href="http://llvm.org/docs/#maillist"> mailing
579lists</a>.</p>
580
581</div>
582
583<!-- *********************************************************************** -->
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