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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 92bd644fd828f8760197aa80a751202f728dbb7f / . / docs / ReleaseNotes.html
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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
Chris Lattner92bd6442008-02-06 18:00:48 +0000[diff] [blame^]26<h1><font color="red">THIS IS A WORK IN PROGRESS FOR THE LLVM 2.2
27RELEASE</font</h1>
28
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]29<!-- *********************************************************************** -->
30<div class="doc_section">
31 <a name="intro">Introduction</a>
32</div>
33<!-- *********************************************************************** -->
34
35<div class="doc_text">
36
37<p>This document contains the release notes for the LLVM compiler
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]38infrastructure, release 2.2. Here we describe the status of LLVM, including
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]39major improvements from the previous release and any known problems. All LLVM
40releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
41releases web site</a>.</p>
42
43<p>For more information about LLVM, including information about the latest
44release, please check out the <a href="http://llvm.org/">main LLVM
45web site</a>. If you have questions or comments, the <a
46href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
47list</a> is a good place to send them.</p>
48
49<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]50main LLVM web page, this document applies to the <i>next</i> release, not the
51current one. To see the release notes for a specific releases, please see the
52<a href="http://llvm.org/releases/">releases page</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]53
54</div>
55
56<!-- *********************************************************************** -->
57<div class="doc_section">
58 <a name="whatsnew">What's New?</a>
59</div>
60<!-- *********************************************************************** -->
61
62<div class="doc_text">
63
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]64<p>This is the thirteenth public release of the LLVM Compiler Infrastructure.
65It includes many features and refinements from LLVM 2.1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]66
67</div>
68
69<!--=========================================================================-->
70<div class="doc_subsection">
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]71<a name="frontends">llvm-gcc 4.0, llvm-gcc 4.2, and clang</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]72</div>
73
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]74<div class="doc_text">
75
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]76<p>LLVM 2.2 fully supports both the llvm-gcc 4.0 and llvm-gcc 4.2 front-ends (in
77LLVM 2.1, llvm-gcc 4.2 was beta). Since LLVM 2.1, the llvm-gcc 4.2 front-end
78has made leaps and bounds and is now at least as good as 4.0 in virtually every
79area, and is better in several areas (for example, exception handling
80correctness). We strongly recommend that you migrate from llvm-gcc 4.0 to
81llvm-gcc 4.2 in this release cycle because <b>LLVM 2.2 is the last release
82that will support llvm-gcc 4.0</b>: LLVM 2.3 will only support the llvm-gcc
834.2 front-end.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]84
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]85<p>The <a href="http://clang.llvm.org/">clang project</a> is an effort to build
86a set of new 'llvm native' front-end technologies for the LLVM optimizer
87and code generator. Currently, its C and Objective-C support is maturing
88nicely, and it has advanced source-to-source analysis and transformation
89capabilities. If you are interested in building source-level tools for C and
90Objective-C (and eventually C++), you should take a look. However, note that
91clang is not an official part of the LLVM 2.2 release. If you are interested in
92this project, please see the web site.</p>
93
94</div>
95
96<!--=========================================================================-->
97<div class="doc_subsection">
98<a name="majorfeatures">Major New Features</a>
99</div>
100
101<div class="doc_text">
102
103<p>Dale contributed full support for long double on x86/x86-64 (where it is 80
104bits) and on Darwin PPC/PPC64 (where it is 128 bits).</p>
105
106<p>Ada, gfortran</p>
107
108<p>
109debug improvements -O0
110EH.
111
112Gordon: GC Revamp. docs/GarbageCollection.html
113
114Kaleidescope: docs/tutorial
115
116Gordon: C and Ocaml Bindings
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]117
118</div>
119
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]120<!--=========================================================================-->
121<div class="doc_subsection">
122<a name="optimizer">Optimizer Improvements</a>
123</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]124
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]125<div class="doc_text">
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]126
Chris Lattner7d2b1102007-09-26 05:44:21 +0000[diff] [blame]127<p>Some of the most noticable feature improvements this release have been in the
128optimizer, speeding it up and making it more aggressive. For example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]129
130<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]131
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]132<li>Daniel Berlin and (?) rewrote Andersen's alias analysis (which is not
133enabled by default) to be several orders of magnitude faster, implmented Offline
134Variable Substitution.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]135
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]136
137Devang: LoopIndexSplit is enabled by default.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]138</ul>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]139
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]140</div>
141
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]142<!--=========================================================================-->
143<div class="doc_subsection">
144<a name="codegen">Code Generator Improvements</a>
145</div>
146
147<div class="doc_text">
148
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]149<p>foci of this release was performance tuning and bug
Chris Lattner7d2b1102007-09-26 05:44:21 +0000[diff] [blame]150 fixing. In addition to these, several new major changes occurred:</p>
151
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]152<ul>
153
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]154<li>Owen contributed Machine Loop info, domintors, etc.</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]155
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]156<li>Dan added support for emitting debug information with .file and .loc on
157targets that support it</li>
158
159<li>Evan physical register dependencies in the BURR scheduler</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]160</ul>
161
162</div>
163
164
165<!--=========================================================================-->
166<div class="doc_subsection">
167<a name="targetspecific">Target Specific Improvements</a>
168</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]169
170<div class="doc_text">
171<p>New features include:
172</p>
173
174<ul>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]175<li>Evan X86 now models EFLAGS in instructions.</li>
176<li>Evan: If conversion on by default for ARM.</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]177</ul>
178
179</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]180
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]181
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]182<!--=========================================================================-->
183<div class="doc_subsection">
184<a name="llvmgccimprovements">llvm-gcc Improvements</a>
185</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]186
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]187<div class="doc_text">
188<p>New features include:
189</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]190
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]191<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]192<li>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]193</ul>
194
195</div>
196
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]197
198<!--=========================================================================-->
199<div class="doc_subsection">
200<a name="coreimprovements">LLVM Core Improvements</a>
201</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]202
203<div class="doc_text">
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]204<p>New features include:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]205</p>
206
207<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]208<li>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]209</ul>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]211</div>
212
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]213<!--=========================================================================-->
214<div class="doc_subsection">
215<a name="otherimprovements">Other Improvements</a>
216</div>
217
218<div class="doc_text">
219<p>New features include:
220</p>
221
222<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]223<li>.</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]224</ul>
225
226</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]227
228<!-- *********************************************************************** -->
229<div class="doc_section">
230 <a name="portability">Portability and Supported Platforms</a>
231</div>
232<!-- *********************************************************************** -->
233
234<div class="doc_text">
235
236<p>LLVM is known to work on the following platforms:</p>
237
238<ul>
239<li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
240 (and probably other unix-like systems).</li>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]241<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]242 64-bit modes.</li>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]243<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]244<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
245 support is available for native builds with Visual C++).</li>
246<li>Sun UltraSPARC workstations running Solaris 8.</li>
247<li>Alpha-based machines running Debian GNU/Linux.</li>
248<li>Itanium-based machines running Linux and HP-UX.</li>
249</ul>
250
251<p>The core LLVM infrastructure uses
252<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
253to the machine and operating system on which it is built. However, minor
254porting may be required to get LLVM to work on new platforms. We welcome your
255portability patches and reports of successful builds or error messages.</p>
256
257</div>
258
259<!-- *********************************************************************** -->
260<div class="doc_section">
261 <a name="knownproblems">Known Problems</a>
262</div>
263<!-- *********************************************************************** -->
264
265<div class="doc_text">
266
267<p>This section contains all known problems with the LLVM system, listed by
268component. As new problems are discovered, they will be added to these
269sections. If you run into a problem, please check the <a
270href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
271there isn't already one.</p>
272
273</div>
274
275<!-- ======================================================================= -->
276<div class="doc_subsection">
277 <a name="experimental">Experimental features included with this release</a>
278</div>
279
280<div class="doc_text">
281
282<p>The following components of this LLVM release are either untested, known to
283be broken or unreliable, or are in early development. These components should
284not be relied on, and bugs should not be filed against them, but they may be
285useful to some people. In particular, if you would like to work on one of these
286components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
287
288<ul>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]289<li>The <tt>-cee</tt> pass is known to be buggy and will be removed in
290 LLVM 2.3.</li>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]291<li>The MSIL, IA64, Alpha, and MIPS backends are experimental.</li>
292<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
293 value for this option.</li>
294<li>The llvmc tool is not supported.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]295</ul>
296
297</div>
298
299<!-- ======================================================================= -->
300<div class="doc_subsection">
301 <a name="x86-be">Known problems with the X86 back-end</a>
302</div>
303
304<div class="doc_text">
305
306<ul>
307<li>The X86 backend does not yet support <a href="http://llvm.org/PR879">inline
308 assembly that uses the X86 floating point stack</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]309<li>The X86 backend occasionally has <a href="http://llvm.org/PR1649">alignment
310 problems</a> on operating systems that don't require 16-byte stack alignment
311 (including most non-darwin OS's like linux).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]312</ul>
313
314</div>
315
316<!-- ======================================================================= -->
317<div class="doc_subsection">
318 <a name="ppc-be">Known problems with the PowerPC back-end</a>
319</div>
320
321<div class="doc_text">
322
323<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]324<li>The Linux PPC32/ABI support needs testing for the interpreter and static
325compilation, and lacks support for debug information.</li>
326</ul>
327
328</div>
329
330<!-- ======================================================================= -->
331<div class="doc_subsection">
332 <a name="arm-be">Known problems with the ARM back-end</a>
333</div>
334
335<div class="doc_text">
336
337<ul>
338<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]339processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]340results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
341<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
342</li>
343<li>There is a bug in QEMU-ARM (<= 0.9.0) which causes it to incorrectly execute
344programs compiled with LLVM. Please use more recent versions of QEMU.</li>
345</ul>
346
347</div>
348
349<!-- ======================================================================= -->
350<div class="doc_subsection">
351 <a name="sparc-be">Known problems with the SPARC back-end</a>
352</div>
353
354<div class="doc_text">
355
356<ul>
357<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
358 support the 64-bit SPARC ABI (-m64).</li>
359</ul>
360
361</div>
362
363<!-- ======================================================================= -->
364<div class="doc_subsection">
365 <a name="alpha-be">Known problems with the Alpha back-end</a>
366</div>
367
368<div class="doc_text">
369
370<ul>
371
372<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
373appropriate nops inserted to ensure restartability.</li>
374
375</ul>
376</div>
377
378<!-- ======================================================================= -->
379<div class="doc_subsection">
380 <a name="ia64-be">Known problems with the IA64 back-end</a>
381</div>
382
383<div class="doc_text">
384
385<ul>
386
387<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
388made where the argument is not 16-byte aligned, as required on IA64. (Strictly
389speaking this is not a bug in the IA64 back-end; it will also be encountered
390when building C++ programs using the C back-end.)</li>
391
392<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
393ABI compliant layout of v-tables</a>. In particular, it just stores function
394pointers instead of function descriptors in the vtable. This bug prevents
395mixing C++ code compiled with LLVM with C++ objects compiled by other C++
396compilers.</li>
397
398<li>There are a few ABI violations which will lead to problems when mixing LLVM
399output with code built with other compilers, particularly for floating-point
400programs.</li>
401
402<li>Defining vararg functions is not supported (but calling them is ok).</li>
403
404<li>The Itanium backend has bitrotted somewhat.</li>
405</ul>
406
407</div>
408
409<!-- ======================================================================= -->
410<div class="doc_subsection">
411 <a name="c-be">Known problems with the C back-end</a>
412</div>
413
414<div class="doc_text">
415
416<ul>
417<li><a href="http://llvm.org/PR802">The C backend does not support inline
418 assembly code</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]419<li><a href="http://llvm.org/PR1126">The C backend does not support vectors
420 yet</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]421<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
422 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
423 C++ code compiled with LLC or native compilers.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]424</ul>
425
426</div>
427
428
429<!-- ======================================================================= -->
430<div class="doc_subsection">
431 <a name="c-fe">Known problems with the C front-end</a>
432</div>
433
434<!-- _______________________________________________________________________ -->
435<div class="doc_subsubsection">Bugs</div>
436
437<div class="doc_text">
438
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]439<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
440Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]441llvmdev mailing list if you are interested.</p>
442
443</div>
444
445<!-- _______________________________________________________________________ -->
446<div class="doc_subsubsection">
447 Notes
448</div>
449
450<div class="doc_text">
451<ul>
452
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]453<li><p>llvm-gcc does <b>not</b> support <tt>__builtin_apply</tt> yet.
454 See <a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</p>
455</li>
456
457<li><p>llvm-gcc <b>partially</b> supports these GCC extensions:</p>
458 <ol>
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]459 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html#Nested%20Functions">Nested Functions</a>:
460
461 As in Algol and Pascal, lexical scoping of functions.
462 Nested functions are supported, but llvm-gcc does not support
Duncan Sands6b761d32007-09-26 16:24:52 +0000[diff] [blame]463 taking the address of a nested function (except on the X86-32 target)
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]464 or non-local gotos.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]465
466 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
467
468 Declaring that functions have no side effects or that they can never
469 return.<br>
470
Anton Korobeynikov08dcc472007-11-16 11:12:01 +0000[diff] [blame]471 <b>Supported:</b> <tt>alias</tt>, <tt>always_inline</tt>, <tt>cdecl</tt>,
472 <tt>const</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]473 <tt>deprecated</tt>, <tt>fastcall</tt>, <tt>format</tt>,
Anton Korobeynikov08dcc472007-11-16 11:12:01 +0000[diff] [blame]474 <tt>format_arg</tt>, <tt>non_null</tt>, <tt>noinline</tt>,
475 <tt>noreturn</tt>, <tt>pure</tt>, <tt>regparm</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]476 <tt>section</tt>, <tt>stdcall</tt>, <tt>unused</tt>, <tt>used</tt>,
477 <tt>visibility</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
478
Anton Korobeynikov08dcc472007-11-16 11:12:01 +0000[diff] [blame]479 <b>Ignored:</b> <tt>nothrow</tt>, <tt>malloc</tt>,
480 <tt>no_instrument_function</tt></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]481 </ol>
482</li>
483
484<li><p>llvm-gcc supports the vast majority of GCC extensions, including:</p>
485
486 <ol>
487 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
488 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
489 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
490 Other built-in functions.</li>
491 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
492 Specifying attributes of variables.</li>
493 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.</li>
494 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
495 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
496 Arrays whose length is computed at run time.</li>
497 <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>
498 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
499 <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>
500 <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>
501 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
502 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
503 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
504 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
505 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
506 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
507 <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>
508 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
509 <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>
510 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
511 <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>
512 <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>
513 <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>
514 <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>
515 <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>
516 <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>
517 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
518 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
519or arrays as values.</li>
520 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.</li>
521 <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>
522 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
523 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
524 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
525 <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>
526 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
527 <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>
528 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
529 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
530 <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>
531 <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>
532 <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>
533 <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>
534 <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>
535 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.</li>
536 </ol></li>
537
538</ul>
539
540<p>If you run into GCC extensions which have not been included in any of these
541lists, please let us know (also including whether or not they work).</p>
542
543</div>
544
545<!-- ======================================================================= -->
546<div class="doc_subsection">
547 <a name="c++-fe">Known problems with the C++ front-end</a>
548</div>
549
550<div class="doc_text">
551
552<p>The C++ front-end is considered to be fully
553tested and works for a number of non-trivial programs, including LLVM
554itself, Qt, Mozilla, etc.</p>
555
556<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]557<li>Exception handling only works well on the X86 and PowerPC targets.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]558</ul>
559
560</div>
561
562
563
564<!-- *********************************************************************** -->
565<div class="doc_section">
566 <a name="additionalinfo">Additional Information</a>
567</div>
568<!-- *********************************************************************** -->
569
570<div class="doc_text">
571
572<p>A wide variety of additional information is available on the <a
573href="http://llvm.org">LLVM web page</a>, in particular in the <a
574href="http://llvm.org/docs/">documentation</a> section. The web page also
575contains versions of the API documentation which is up-to-date with the
576Subversion version of the source code.
577You can access versions of these documents specific to this release by going
578into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
579
580<p>If you have any questions or comments about LLVM, please feel free to contact
581us via the <a href="http://llvm.org/docs/#maillist"> mailing
582lists</a>.</p>
583
584</div>
585
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