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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 0d1769155f43e7505bbe41916df2c0ca8548b03d / . / docs / ReleaseNotes.html
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Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]8 <title>LLVM 2.3 Release Notes</title>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]9</head>
10<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]11
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]12<div class="doc_title">LLVM 2.3 Release Notes</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]13
14<ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]15 <li><a href="#intro">Introduction</a></li>
16 <li><a href="#whatsnew">What's New?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +0000[diff] [blame]17 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]18 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]19 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]20 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]21</ol>
22
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]23<div class="doc_author">
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]24 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]25</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]26
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]27<!-- Done through Week-of-Mon-20080324.txt -->
28
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]29<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]30<div class="doc_section">
31 <a name="intro">Introduction</a>
32</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]33<!-- *********************************************************************** -->
34
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]35<div class="doc_text">
36
37<p>This document contains the release notes for the LLVM compiler
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]38infrastructure, release 2.3. Here we describe the status of LLVM, including
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]39major improvements from the previous release and any known problems. All LLVM
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]40releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]41releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]42
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]43<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]44release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]45web site</a>. If you have questions or comments, the <a
46href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]47list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]48
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]49<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner84977642007-09-21 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>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]53
54</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]55
56<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]57<div class="doc_section">
58 <a name="whatsnew">What's New?</a>
59</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]60<!-- *********************************************************************** -->
61
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]62<div class="doc_text">
63
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]64<p>This is the fourteenth public release of the LLVM Compiler Infrastructure.
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]65It includes a large number of features and refinements from LLVM 2.2.</p>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]66
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]67</div>
68
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]69<!-- Unfinished features in 2.3:
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]70 Machine LICM
71 Machine Sinking
72 LegalizeDAGTypes
73 -->
74
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]75<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]76<div class="doc_subsection">
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]77<a name="changes">Major Changes in LLVM 2.3</a>
Chris Lattnerb4c68cd2008-02-10 07:04:35 +0000[diff] [blame]78</div>
79
80<div class="doc_text">
81
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]82<p>LLVM 2.2 was the last LLVM release to support llvm-gcc 4.0 and llvm-upgrade.
83llvm-gcc 4.0 has been replaced with llvm-gcc 4.2. llvm-upgrade was useful for
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]84upgrading LLVM 1.9 files to LLVM 2.x syntax, but you can always use a previous
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]85LLVM release to do this. One nice impact of this is that the LLVM regression
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]86test suite no longer depends on llvm-upgrade, which makes it run faster.</p>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]87
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]88<p>LLVM API Changes:</p>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]89
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]90<ul>
91<li>Several core LLVM IR classes have migrated to use 'FOOCLASS::Create(...)'
92 instead of 'new FOOCLASS(...)' (e.g. where FOOCLASS=BasicBlock). We hope to
93 standardize on FOOCLASS::Create for all IR classes in the future, but not
94 all of them have been moved over yet.</li>
95<li>LLVM 2.3 renames the LLVMBuilder and LLVMFoldingBuilder classes to
96 IRBuilder.</li>
97<li>MRegisterInfo was renamed to TargetRegisterInfo.</li>
98<li>The MappedFile class is gone, please use MemoryBuffer instead.</li>
99<li>The '-enable-eh' flag to LLC has been removed. Now code should encode
100 whether it is safe to not generate unwind information for a function by
101 tagging the Function object with the 'nounwind' attribute.</li>
102
103</ul>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]104</div>
105
106<!--=========================================================================-->
107<div class="doc_subsection">
108<a name="majorfeatures">Major New Features</a>
109</div>
110
111<div class="doc_text">
112
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]113<p>LLVM 2.3 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]114
115<ul>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]116<li>Multiple Return Value Support</li>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]117
118
119<li><p>LLVM 2.3 includes a complete reimplementation of the "llvmc" tool. It is
120designed to overcome several problems of the original llvmc and to provide a
121superset of the features as the 'gcc' driver.</p>
122
123<p>The main features of llvmc2 is:</p>
124
125<ul>
126<li>Extended handling of command line options and smart rules for
127dispatching them to different tools.</li>
128<li>Flexible (and extensible) rules for defining different tools.</li>
129<li>The different intermediate steps performed by tools are represented
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]130as edges in the abstract graph.</li>
131<li>The 'language' for driver behaviour definition is tablegen and thus
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]132it's relatively easy to add new features.</li>
133<li>The definition of driver is transformed into set of C++ classes, thus
134no runtime interpretation is needed.</li>
135</ul>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]136</li>
137
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]138
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]139<li>Reimplemented <a href="LinkTimeOptimization.html">LTO interface</a> in
140 C.</li>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]141
142
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]143<li>kaleidoscope tutorial in ocaml.</li>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]144
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]145</ul>
146
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]147</div>
148
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]149
150<!--=========================================================================-->
151<div class="doc_subsection">
152<a name="frontends">llvm-gcc 4.2 Improvements and Clang</a>
153</div>
154
155<div class="doc_text">
156
157<p>LLVM 2.3 fully supports llvm-gcc 4.2 front-end.</p>
158
159<p>llvm-gcc 4.2 includes numerous fixes to better support the Objective-C
160front-end. Objective-C now works very well on Mac OS/X.</p>
161
162<p>llvm-gcc 4.2 includes many other fixes which improve conformance with the
163relevant parts of the GCC testsuite.</p>
164
165<p>The <a href="http://clang.llvm.org/">clang project</a> is an effort to build
166a set of new 'llvm native' front-end technologies for the LLVM optimizer
167and code generator. Currently, its C and Objective-C support is maturing
168nicely, and it has advanced source-to-source analysis and transformation
169capabilities. If you are interested in building source-level tools for C and
170Objective-C (and eventually C++), you should take a look. However, note that
171clang is not an official part of the LLVM 2.3 release. If you are interested in
172this project, please see its <a href="http://clang.llvm.org/">web site</a>.</p>
173
174</div>
175
176
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]177<!--=========================================================================-->
178<div class="doc_subsection">
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]179<a name="coreimprovements">LLVM Core Improvements</a>
180</div>
181
182<div class="doc_text">
183<p>New features include:
184</p>
185
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]186
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]187Common linkage?
188
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]189Atomic operation support, Alpha, X86, X86-64, PowerPC. "__sync_synchronize",
Anton Korobeynikov0d176912008-06-08 10:23:46 +0000[diff] [blame^]190"__sync_val_compare_and_swap", etc
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]191
192<ul>
Gordon Henriksen1494bcc2008-06-05 12:51:50 +0000[diff] [blame]193<li>The C and Ocaml bindings have received additional improvements. The
194bindings now cover pass managers, several transformation passes, iteration
195over the LLVM IR, target data, and parameter attribute lists.</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]196</ul>
197
198</div>
199
200<!--=========================================================================-->
201<div class="doc_subsection">
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]202<a name="optimizer">Optimizer Improvements</a>
203</div>
204
205<div class="doc_text">
206
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]207<p>In addition to a huge array of bug fixes and minor performance tweaks, the
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]208LLVM 2.3 optimizers support a few major enhancements:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]209
210<ul>
211
Devang Patel83a15d72008-06-05 21:44:00 +0000[diff] [blame]212<li>Loop index set splitting on by default.<p>
213This transformation hoists conditions from loop bodies and reduces loop's
214iteration space to improve performance. For example, <p>
215<pre>
216for (i = LB; i < UB; ++i)
217 if (i <= NV)
218 LOOP_BODY
219</pre>
220is transformed into
221<pre>
222NUB = min(NV+1, UB)
223for (i = LB; i < NUB; ++i)
224 LOOP_BODY
225</pre>
226</li>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]227
228<li>LLVM includes a new <tt>memcpy</tt> optimization pass which optimizes out
229dead <tt>memcpy</tt> calls, unneeded copies of aggregates, and handles the
230return slot optimization. The LLVM optimizer now notices long sequences of
231consequtive stores and merges them into <tt>memcpy</tt>s where profitable.</li>
232
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]233<li>Alignment detection for vector memory references and for <tt>memcpy</tt> and
234<tt>memset</tt> is now more aggressive.</li>
Owen Anderson30073ff2008-06-06 16:23:15 +0000[diff] [blame]235
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]236<li>The aggressive dead code elimination (ADCE) optimization has been rewritten
237to make it both faster and safer in the presence of code containing infinite
238loops. Some of its prior functionality has been factored out into the loop
239deletion pass, which <em>is</em> safe for infinite loops.</li>
240
241<li>Several optimizations have been sped up, leading to faster code generation
242 with the same code quality.</li>
243
244<li>The 'SimplifyLibCalls' pass, which optimizes calls to libc and libm
245 functions for C-based languages, has been rewritten to be a FunctionPass
246 instead a ModulePass. This allows it to be run more often and to be
247 included at -O1 in llvm-gcc. It was also extended to include more
248 optimizations and several corner case bugs are fixed.</li>
249
250<li>LLVM now includes a simple 'Jump Threading' pass, which attemps to simplify
251 the conditional branches with information about predecessor blocks. This
252 simplifies the control flow graph. This pass is pretty basic at this point,
253 but catches some important cases and provides a foundation to build off
254 of.</li>
255</ul>
256
257</div>
258
259<!--=========================================================================-->
260<div class="doc_subsection">
261<a name="codegen">Code Generator Improvements</a>
262</div>
263
264<div class="doc_text">
265
266<p>We put a significant amount of work into the code generator infrastructure,
267which allows us to implement more aggressive algorithms and make it run
268faster:</p>
269
270<ul>
271<li>MemOperand in the code generator: describe me!.</li>
272
273<li>The target-independent code generator infrastructure now uses LLVM's APInt
274 class to handle integer values, which allows it to support integer types
275 larger than 64 bits. Note that support for such types is also dependent on
276 target-specific support. Use of APInt is also a step toward support for
277 non-power-of-2 integer sizes.</li>
278
279<li>Several compile time speedups for code with large basic blocks.</li>
280
281<li>Several improvements which make llc's <tt>--view-sunit-dags</tt>
282 visualization of scheduling dependency graphs easier to understand.</li>
283
284<li>The code generator allows targets to write patterns that generate subreg
285 references directly in .td files now.</li>
286
287<li><tt>memcpy</tt> lowering in the backend is more aggressive, particularly for
288 <tt>memcpy</tt> calls introduced by the code generator when handling
289 pass-by-value structure argument copies.</li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]290</ul>
291
292</div>
293
294
295<!--=========================================================================-->
296<div class="doc_subsection">
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]297<a name="x86specific">X86/X86-64 Specific Improvements</a>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]298</div>
Chris Lattner60893e52007-05-18 06:33:02 +0000[diff] [blame]299
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]300<div class="doc_text">
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]301<p>New target-specific features include:
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]302</p>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]303
304<ul>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]305<li>llvm-gcc's X86-64 ABI conformance is far improved, particularly in the
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]306 area of passing and returning structures by value. llvm-gcc compiled code
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]307 now interoperates very well on X86-64 systems with other compilers.</li>
308
309<li>The LLVM X86 backend now supports the support SSE 4.1 instruction set, and
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]310 the llvm-gcc 4.2 front-end supports the SSE 4.1 compiler builtins. Various
311 generic vector operations (insert/extract/shuffle) are much more efficient
312 when SSE 4.1 is enabled. The JIT automatically takes advantage of these
313 instructions, but llvm-gcc must be explicitly told to use them, e.g. with
314 <tt>-march=penryn</tt>.</li>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]315
316<li>The X86 backend now does a number of optimizations that aim to avoid
317 converting numbers back and forth from SSE registers to the X87 floating
318 point stack.</li>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]319
320<li>The X86 backend supports stack realignment, which is particularly useful for
321 vector code on OS's without 16-byte aligned stacks.</li>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]322
323<li>The X86 backend now supports the "sseregparm" options in GCC, which allow
324 functions to be tagged as passing floating point values in SSE
325 registers.</li>
326
327<li>Trampolines (taking the address of a nested function) now work on
328 Linux/x86-64.</li>
329
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]330<li><tt>__builtin_prefetch</tt> is now compiled into the appropriate prefetch
331 instructions instead of being ignored.</li>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]332
Dan Gohman4e16d402008-06-05 16:15:39 +0000[diff] [blame]333<li>128-bit integers are now supported on x86-64 targets.</li>
334
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]335<li>The register allocator can now rematerialize PIC-base computations.</li>
336
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000[diff] [blame]337</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]338
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000[diff] [blame]339</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]340
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]341<!--=========================================================================-->
342<div class="doc_subsection">
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]343<a name="targetspecific">Other Target Specific Improvements</a>
344</div>
345
346<div class="doc_text">
347<p>New target-specific features include:
348</p>
349
350<ul>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]351<li>The LLVM C backend now supports vector code.</li>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]352
353
354</ul>
355
356</div>
357
358
359
360<!--=========================================================================-->
361<div class="doc_subsection">
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]362<a name="otherimprovements">Other Improvements</a>
363</div>
364
365<div class="doc_text">
366<p>New features include:
367</p>
368
369<ul>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]370<li>LLVM now builds with GCC 4.3.</li>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]371<li><tt>llvm2cpp</tt> tool has been folded into llc, use
372 <tt>llc -march=cpp</tt></li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]373</ul>
374
375</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]376
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]377<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]378<div class="doc_section">
379 <a name="portability">Portability and Supported Platforms</a>
380</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]381<!-- *********************************************************************** -->
382
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]383<div class="doc_text">
384
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]385<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]386
387<ul>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]388<li>Intel and AMD machines (IA32) running Red Hat Linux, Fedora Core and FreeBSD
Reid Spencer00812e22005-05-17 02:47:27 +0000[diff] [blame]389 (and probably other unix-like systems).</li>
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]390<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit and
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]391 64-bit modes.</li>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]392<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]393<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
394 support is available for native builds with Visual C++).</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]395<li>Sun UltraSPARC workstations running Solaris 10.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]396<li>Alpha-based machines running Debian GNU/Linux.</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]397<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]398</ul>
399
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]400<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]401to the machine and operating system on which it is built. However, minor
402porting may be required to get LLVM to work on new platforms. We welcome your
403portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]404
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]405</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]406
407<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]408<div class="doc_section">
409 <a name="knownproblems">Known Problems</a>
410</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]411<!-- *********************************************************************** -->
412
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]413<div class="doc_text">
414
415<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]416component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]417sections. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]418href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]419there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]420
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]421</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]422
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]423<!-- ======================================================================= -->
424<div class="doc_subsection">
425 <a name="experimental">Experimental features included with this release</a>
426</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]427
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]428<div class="doc_text">
429
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]430<p>The following components of this LLVM release are either untested, known to
431be broken or unreliable, or are in early development. These components should
432not be relied on, and bugs should not be filed against them, but they may be
433useful to some people. In particular, if you would like to work on one of these
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]434components, please contact us on the <a
435href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]436
437<ul>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]438<li>The MSIL, IA64, Alpha, SPU, and MIPS backends are experimental.</li>
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]439<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
440 value for this option.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]441</ul>
442
443</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]444
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]445<!-- ======================================================================= -->
446<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]447 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]448</div>
449
450<div class="doc_text">
451
452<ul>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]453<li>The X86 backend does not yet support all <a
454 href="http://llvm.org/PR879">inline assembly that uses the X86 floating
455 point stack</a>. It supports the 'f' and 't' constraints, but not 'u'.</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]456<li>The X86 backend generates inefficient floating point code when configured to
457 generate code for systems that don't have SSE2.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]458</ul>
459
460</div>
461
462<!-- ======================================================================= -->
463<div class="doc_subsection">
464 <a name="ppc-be">Known problems with the PowerPC back-end</a>
465</div>
466
467<div class="doc_text">
468
469<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000[diff] [blame]470<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]471compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]472</ul>
473
474</div>
475
476<!-- ======================================================================= -->
477<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]478 <a name="arm-be">Known problems with the ARM back-end</a>
479</div>
480
481<div class="doc_text">
482
483<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]484<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000[diff] [blame]485processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]486results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]487<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
488</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]489<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly execute
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]490programs compiled with LLVM. Please use more recent versions of QEMU.</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]491</ul>
492
493</div>
494
495<!-- ======================================================================= -->
496<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]497 <a name="sparc-be">Known problems with the SPARC back-end</a>
498</div>
499
500<div class="doc_text">
501
502<ul>
503<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
504 support the 64-bit SPARC ABI (-m64).</li>
505</ul>
506
507</div>
508
509<!-- ======================================================================= -->
510<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]511 <a name="alpha-be">Known problems with the Alpha back-end</a>
512</div>
513
514<div class="doc_text">
515
516<ul>
517
518<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
519appropriate nops inserted to ensure restartability.</li>
520
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]521</ul>
522</div>
523
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]524<!-- ======================================================================= -->
525<div class="doc_subsection">
526 <a name="ia64-be">Known problems with the IA64 back-end</a>
527</div>
528
529<div class="doc_text">
530
531<ul>
532
533<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
534made where the argument is not 16-byte aligned, as required on IA64. (Strictly
535speaking this is not a bug in the IA64 back-end; it will also be encountered
536when building C++ programs using the C back-end.)</li>
537
538<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
539ABI compliant layout of v-tables</a>. In particular, it just stores function
540pointers instead of function descriptors in the vtable. This bug prevents
541mixing C++ code compiled with LLVM with C++ objects compiled by other C++
542compilers.</li>
543
544<li>There are a few ABI violations which will lead to problems when mixing LLVM
545output with code built with other compilers, particularly for floating-point
546programs.</li>
547
548<li>Defining vararg functions is not supported (but calling them is ok).</li>
549
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]550<li>The Itanium backend has bitrotted somewhat.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]551</ul>
552
553</div>
554
555<!-- ======================================================================= -->
556<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]557 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]558</div>
559
560<div class="doc_text">
561
562<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]563<li><a href="http://llvm.org/PR802">The C backend has only basic support for
564 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000[diff] [blame]565<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
566 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
567 C++ code compiled with LLC or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]568<li>The C backend does not support all exception handling constructs.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]569</ul>
570
571</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]572
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]573
574<!-- ======================================================================= -->
575<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]576 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]577</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]578
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]579<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]580<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]581
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]582<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]583
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]584<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
585Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]586llvmdev mailing list if you are interested.</p>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]587
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]588<p>The only major language feature of GCC not supported by llvm-gcc is
589 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
590 are only supported on some targets. For example, trampolines are only
591 supported on some targets, which are used when you take the address of a
592 nested function.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]593
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]594<p>If you run into GCC extensions which are not supported, please let us know.
595</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]596
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]597</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]598
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]599<!-- ======================================================================= -->
600<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]601 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]602</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]603
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]604<div class="doc_text">
605
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]606<p>The C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]607tested and works for a number of non-trivial programs, including LLVM
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]608itself, Qt, Mozilla, etc.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]609
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]610<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]611<li>Exception handling works well on the X86 and PowerPC targets, including
612x86-64 darwin. This works when linking to a libstdc++ compiled by GCC. It is
613supported on x86-64 linux, but that is disabled by default in this release.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]614</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]615
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]616</div>
617
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]618
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]619<!-- ======================================================================= -->
620<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]621 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]622</div>
623
624<div class="doc_text">
625The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
626technology and problems should be expected.
627<ul>
628<li>The Ada front-end currently only builds on x86-32. This is mainly due
629to lack of trampoline support (pointers to nested functions) on other platforms,
630however it <a href="http://llvm.org/PR2006">also fails to build on x86-64</a>
631which does support trampolines.</li>
632<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
633Workaround: configure with --disable-bootstrap.</li>
634<li>The c380004 and <a href="http://llvm.org/PR2010">c393010</a> ACATS tests
635fail (c380004 also fails with gcc-4.2 mainline).</li>
636<li>Many gcc specific Ada tests continue to crash the compiler.</li>
637<li>The -E binder option (exception backtraces)
638<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
639crashing if an exception is raised. Workaround: do not use -E.</li>
640<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
641or finish at a non-byte offset</a> in a record. Workaround: do not pack records
642or use representation clauses that result in a field of a non-discrete type
643starting or finishing in the middle of a byte.</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]644<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers 'main'
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]645as generated by the Ada binder to be invalid</a>.
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]646Workaround: hand edit the file to use pointers for <tt>argv</tt> and <tt>envp</tt> rather than
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]647integers.</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]648<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is ignored</a>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]649</ul>
650</div>
651
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]652<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]653<div class="doc_section">
654 <a name="additionalinfo">Additional Information</a>
655</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]656<!-- *********************************************************************** -->
657
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]658<div class="doc_text">
659
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]660<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]661href="http://llvm.org">LLVM web page</a>, in particular in the <a
662href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]663contains versions of the API documentation which is up-to-date with the
664Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]665You can access versions of these documents specific to this release by going
666into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]667
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]668<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]669us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]670lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]671
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]672</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]673
674<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]675
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]676<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]677<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]678 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]679 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
680 <a href="http://validator.w3.org/check/referer"><img
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]681 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]682
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]683 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]684 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]685</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]686
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]687</body>
688</html>