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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 358c3274a260557883a1b74d4e3beecc1caa356f / . / 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 Lattner358c3272008-02-06 18:32:06 +0000[diff] [blame^]132<li>Daniel Berlin and (Curtis?) rewrote Andersen's alias analysis (which is not
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]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 Lattner358c3272008-02-06 18:32:06 +0000[diff] [blame^]154<li>Owen contributed Machine Loop info, domintors, etc. Merged dom and
155 postdom.</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]156
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]157<li>Dan added support for emitting debug information with .file and .loc on
158targets that support it</li>
159
160<li>Evan physical register dependencies in the BURR scheduler</li>
Chris Lattner358c3272008-02-06 18:32:06 +0000[diff] [blame^]161
162<li>Evan EXTRACT_SUBREG coalescing support</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]163</ul>
164
165</div>
166
167
168<!--=========================================================================-->
169<div class="doc_subsection">
170<a name="targetspecific">Target Specific Improvements</a>
171</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]172
173<div class="doc_text">
174<p>New features include:
175</p>
176
177<ul>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]178<li>Evan X86 now models EFLAGS in instructions.</li>
179<li>Evan: If conversion on by default for ARM.</li>
Chris Lattner358c3272008-02-06 18:32:06 +0000[diff] [blame^]180<li>Bruno: MIPS PIC support.</li>
181<li>Arnold Schwaighofer: X86 tail call support.</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]182</ul>
183
184</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]185
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]186
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]187<!--=========================================================================-->
188<div class="doc_subsection">
189<a name="llvmgccimprovements">llvm-gcc Improvements</a>
190</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]191
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]192<div class="doc_text">
193<p>New features include:
194</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]195
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]196<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]197<li>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]198</ul>
199
200</div>
201
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]202
203<!--=========================================================================-->
204<div class="doc_subsection">
205<a name="coreimprovements">LLVM Core Improvements</a>
206</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]207
208<div class="doc_text">
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]209<p>New features include:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]210</p>
211
212<ul>
Chris Lattner358c3272008-02-06 18:32:06 +0000[diff] [blame^]213<li>Devang added LLVMFoldingBuilder.</li>
214<li>Dan added support for vector sin, cos, and pow intrinsics.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]215</ul>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]216
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]217</div>
218
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]219<!--=========================================================================-->
220<div class="doc_subsection">
221<a name="otherimprovements">Other Improvements</a>
222</div>
223
224<div class="doc_text">
225<p>New features include:
226</p>
227
228<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]229<li>.</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]230</ul>
231
232</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]233
234<!-- *********************************************************************** -->
235<div class="doc_section">
236 <a name="portability">Portability and Supported Platforms</a>
237</div>
238<!-- *********************************************************************** -->
239
240<div class="doc_text">
241
242<p>LLVM is known to work on the following platforms:</p>
243
244<ul>
245<li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
246 (and probably other unix-like systems).</li>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]247<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]248 64-bit modes.</li>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]249<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]250<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
251 support is available for native builds with Visual C++).</li>
252<li>Sun UltraSPARC workstations running Solaris 8.</li>
253<li>Alpha-based machines running Debian GNU/Linux.</li>
254<li>Itanium-based machines running Linux and HP-UX.</li>
255</ul>
256
257<p>The core LLVM infrastructure uses
258<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
259to the machine and operating system on which it is built. However, minor
260porting may be required to get LLVM to work on new platforms. We welcome your
261portability patches and reports of successful builds or error messages.</p>
262
263</div>
264
265<!-- *********************************************************************** -->
266<div class="doc_section">
267 <a name="knownproblems">Known Problems</a>
268</div>
269<!-- *********************************************************************** -->
270
271<div class="doc_text">
272
273<p>This section contains all known problems with the LLVM system, listed by
274component. As new problems are discovered, they will be added to these
275sections. If you run into a problem, please check the <a
276href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
277there isn't already one.</p>
278
279</div>
280
281<!-- ======================================================================= -->
282<div class="doc_subsection">
283 <a name="experimental">Experimental features included with this release</a>
284</div>
285
286<div class="doc_text">
287
288<p>The following components of this LLVM release are either untested, known to
289be broken or unreliable, or are in early development. These components should
290not be relied on, and bugs should not be filed against them, but they may be
291useful to some people. In particular, if you would like to work on one of these
292components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
293
294<ul>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]295<li>The <tt>-cee</tt> pass is known to be buggy and will be removed in
296 LLVM 2.3.</li>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]297<li>The MSIL, IA64, Alpha, and MIPS backends are experimental.</li>
298<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
299 value for this option.</li>
300<li>The llvmc tool is not supported.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]301</ul>
302
303</div>
304
305<!-- ======================================================================= -->
306<div class="doc_subsection">
307 <a name="x86-be">Known problems with the X86 back-end</a>
308</div>
309
310<div class="doc_text">
311
312<ul>
313<li>The X86 backend does not yet support <a href="http://llvm.org/PR879">inline
314 assembly that uses the X86 floating point stack</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]315<li>The X86 backend occasionally has <a href="http://llvm.org/PR1649">alignment
316 problems</a> on operating systems that don't require 16-byte stack alignment
317 (including most non-darwin OS's like linux).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]318</ul>
319
320</div>
321
322<!-- ======================================================================= -->
323<div class="doc_subsection">
324 <a name="ppc-be">Known problems with the PowerPC back-end</a>
325</div>
326
327<div class="doc_text">
328
329<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]330<li>The Linux PPC32/ABI support needs testing for the interpreter and static
331compilation, and lacks support for debug information.</li>
332</ul>
333
334</div>
335
336<!-- ======================================================================= -->
337<div class="doc_subsection">
338 <a name="arm-be">Known problems with the ARM back-end</a>
339</div>
340
341<div class="doc_text">
342
343<ul>
344<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]345processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]346results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
347<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
348</li>
349<li>There is a bug in QEMU-ARM (<= 0.9.0) which causes it to incorrectly execute
350programs compiled with LLVM. Please use more recent versions of QEMU.</li>
351</ul>
352
353</div>
354
355<!-- ======================================================================= -->
356<div class="doc_subsection">
357 <a name="sparc-be">Known problems with the SPARC back-end</a>
358</div>
359
360<div class="doc_text">
361
362<ul>
363<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
364 support the 64-bit SPARC ABI (-m64).</li>
365</ul>
366
367</div>
368
369<!-- ======================================================================= -->
370<div class="doc_subsection">
371 <a name="alpha-be">Known problems with the Alpha back-end</a>
372</div>
373
374<div class="doc_text">
375
376<ul>
377
378<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
379appropriate nops inserted to ensure restartability.</li>
380
381</ul>
382</div>
383
384<!-- ======================================================================= -->
385<div class="doc_subsection">
386 <a name="ia64-be">Known problems with the IA64 back-end</a>
387</div>
388
389<div class="doc_text">
390
391<ul>
392
393<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
394made where the argument is not 16-byte aligned, as required on IA64. (Strictly
395speaking this is not a bug in the IA64 back-end; it will also be encountered
396when building C++ programs using the C back-end.)</li>
397
398<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
399ABI compliant layout of v-tables</a>. In particular, it just stores function
400pointers instead of function descriptors in the vtable. This bug prevents
401mixing C++ code compiled with LLVM with C++ objects compiled by other C++
402compilers.</li>
403
404<li>There are a few ABI violations which will lead to problems when mixing LLVM
405output with code built with other compilers, particularly for floating-point
406programs.</li>
407
408<li>Defining vararg functions is not supported (but calling them is ok).</li>
409
410<li>The Itanium backend has bitrotted somewhat.</li>
411</ul>
412
413</div>
414
415<!-- ======================================================================= -->
416<div class="doc_subsection">
417 <a name="c-be">Known problems with the C back-end</a>
418</div>
419
420<div class="doc_text">
421
422<ul>
423<li><a href="http://llvm.org/PR802">The C backend does not support inline
424 assembly code</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]425<li><a href="http://llvm.org/PR1126">The C backend does not support vectors
426 yet</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]427<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
428 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
429 C++ code compiled with LLC or native compilers.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]430</ul>
431
432</div>
433
434
435<!-- ======================================================================= -->
436<div class="doc_subsection">
437 <a name="c-fe">Known problems with the C front-end</a>
438</div>
439
440<!-- _______________________________________________________________________ -->
441<div class="doc_subsubsection">Bugs</div>
442
443<div class="doc_text">
444
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]445<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
446Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]447llvmdev mailing list if you are interested.</p>
448
449</div>
450
451<!-- _______________________________________________________________________ -->
452<div class="doc_subsubsection">
453 Notes
454</div>
455
456<div class="doc_text">
457<ul>
458
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]459<li><p>llvm-gcc does <b>not</b> support <tt>__builtin_apply</tt> yet.
460 See <a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</p>
461</li>
462
463<li><p>llvm-gcc <b>partially</b> supports these GCC extensions:</p>
464 <ol>
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]465 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html#Nested%20Functions">Nested Functions</a>:
466
467 As in Algol and Pascal, lexical scoping of functions.
468 Nested functions are supported, but llvm-gcc does not support
Duncan Sands6b761d32007-09-26 16:24:52 +0000[diff] [blame]469 taking the address of a nested function (except on the X86-32 target)
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]470 or non-local gotos.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]471
472 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
473
474 Declaring that functions have no side effects or that they can never
475 return.<br>
476
Anton Korobeynikov08dcc472007-11-16 11:12:01 +0000[diff] [blame]477 <b>Supported:</b> <tt>alias</tt>, <tt>always_inline</tt>, <tt>cdecl</tt>,
478 <tt>const</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]479 <tt>deprecated</tt>, <tt>fastcall</tt>, <tt>format</tt>,
Anton Korobeynikov08dcc472007-11-16 11:12:01 +0000[diff] [blame]480 <tt>format_arg</tt>, <tt>non_null</tt>, <tt>noinline</tt>,
481 <tt>noreturn</tt>, <tt>pure</tt>, <tt>regparm</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]482 <tt>section</tt>, <tt>stdcall</tt>, <tt>unused</tt>, <tt>used</tt>,
483 <tt>visibility</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
484
Anton Korobeynikov08dcc472007-11-16 11:12:01 +0000[diff] [blame]485 <b>Ignored:</b> <tt>nothrow</tt>, <tt>malloc</tt>,
486 <tt>no_instrument_function</tt></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]487 </ol>
488</li>
489
490<li><p>llvm-gcc supports the vast majority of GCC extensions, including:</p>
491
492 <ol>
493 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
494 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
495 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
496 Other built-in functions.</li>
497 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
498 Specifying attributes of variables.</li>
499 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.</li>
500 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
501 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
502 Arrays whose length is computed at run time.</li>
503 <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>
504 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
505 <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>
506 <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>
507 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
508 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
509 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
510 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
511 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
512 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
513 <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>
514 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
515 <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>
516 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
517 <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>
518 <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>
519 <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>
520 <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>
521 <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>
522 <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>
523 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
524 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
525or arrays as values.</li>
526 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.</li>
527 <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>
528 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
529 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
530 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
531 <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>
532 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
533 <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>
534 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
535 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
536 <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>
537 <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>
538 <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>
539 <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>
540 <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>
541 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.</li>
542 </ol></li>
543
544</ul>
545
546<p>If you run into GCC extensions which have not been included in any of these
547lists, please let us know (also including whether or not they work).</p>
548
549</div>
550
551<!-- ======================================================================= -->
552<div class="doc_subsection">
553 <a name="c++-fe">Known problems with the C++ front-end</a>
554</div>
555
556<div class="doc_text">
557
558<p>The C++ front-end is considered to be fully
559tested and works for a number of non-trivial programs, including LLVM
560itself, Qt, Mozilla, etc.</p>
561
562<ul>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]563<li>Exception handling only works well on the X86 and PowerPC targets.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]564</ul>
565
566</div>
567
568
569
570<!-- *********************************************************************** -->
571<div class="doc_section">
572 <a name="additionalinfo">Additional Information</a>
573</div>
574<!-- *********************************************************************** -->
575
576<div class="doc_text">
577
578<p>A wide variety of additional information is available on the <a
579href="http://llvm.org">LLVM web page</a>, in particular in the <a
580href="http://llvm.org/docs/">documentation</a> section. The web page also
581contains versions of the API documentation which is up-to-date with the
582Subversion version of the source code.
583You can access versions of these documents specific to this release by going
584into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
585
586<p>If you have any questions or comments about LLVM, please feel free to contact
587us via the <a href="http://llvm.org/docs/#maillist"> mailing
588lists</a>.</p>
589
590</div>
591
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