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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
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]309<li>Support for Win64 was added. This includes codegeneration itself, JIT
310 support and necessary changes to llvm-gcc.</li>
311
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]312<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]313 the llvm-gcc 4.2 front-end supports the SSE 4.1 compiler builtins. Various
314 generic vector operations (insert/extract/shuffle) are much more efficient
315 when SSE 4.1 is enabled. The JIT automatically takes advantage of these
316 instructions, but llvm-gcc must be explicitly told to use them, e.g. with
317 <tt>-march=penryn</tt>.</li>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]318
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]319<li>The X86 backend now does a number of optimizations that aim to avoid
320 converting numbers back and forth from SSE registers to the X87 floating
321 point stack.</li>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]322
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]323<li>The X86 backend supports stack realignment, which is particularly useful for
324 vector code on OS's without 16-byte aligned stacks.</li>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]325
326<li>The X86 backend now supports the "sseregparm" options in GCC, which allow
327 functions to be tagged as passing floating point values in SSE
328 registers.</li>
329
330<li>Trampolines (taking the address of a nested function) now work on
331 Linux/x86-64.</li>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]332
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]333<li><tt>__builtin_prefetch</tt> is now compiled into the appropriate prefetch
334 instructions instead of being ignored.</li>
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]335
Dan Gohman4e16d402008-06-05 16:15:39 +0000[diff] [blame]336<li>128-bit integers are now supported on x86-64 targets.</li>
337
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]338<li>The register allocator can now rematerialize PIC-base computations.</li>
339
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000[diff] [blame]340</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]341
Chris Lattnerbfb17ab2007-05-17 21:41:31 +0000[diff] [blame]342</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]343
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]344<!--=========================================================================-->
345<div class="doc_subsection">
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]346<a name="targetspecific">Other Target Specific Improvements</a>
347</div>
348
349<div class="doc_text">
350<p>New target-specific features include:
351</p>
352
353<ul>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]354<li>The LLVM C backend now supports vector code.</li>
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]355
356
357</ul>
358
359</div>
360
361
362
363<!--=========================================================================-->
364<div class="doc_subsection">
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]365<a name="otherimprovements">Other Improvements</a>
366</div>
367
368<div class="doc_text">
369<p>New features include:
370</p>
371
372<ul>
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]373<li>LLVM now builds with GCC 4.3.</li>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]374<li><tt>llvm2cpp</tt> tool has been folded into llc, use
375 <tt>llc -march=cpp</tt></li>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]376</ul>
377
378</div>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]379
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]380<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]381<div class="doc_section">
382 <a name="portability">Portability and Supported Platforms</a>
383</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]384<!-- *********************************************************************** -->
385
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]386<div class="doc_text">
387
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]388<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]389
390<ul>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]391<li>Intel and AMD machines (IA32) running Red Hat Linux, Fedora Core and FreeBSD
Reid Spencer00812e22005-05-17 02:47:27 +0000[diff] [blame]392 (and probably other unix-like systems).</li>
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]393<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]394 64-bit modes.</li>
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]395<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]396<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
397 support is available for native builds with Visual C++).</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]398<li>Sun UltraSPARC workstations running Solaris 10.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]399<li>Alpha-based machines running Debian GNU/Linux.</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]400<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]401</ul>
402
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000[diff] [blame]403<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]404to the machine and operating system on which it is built. However, minor
405porting may be required to get LLVM to work on new platforms. We welcome your
406portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]407
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]408</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]409
410<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]411<div class="doc_section">
412 <a name="knownproblems">Known Problems</a>
413</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]414<!-- *********************************************************************** -->
415
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]416<div class="doc_text">
417
418<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]419component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]420sections. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]421href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]422there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]423
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]424</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]425
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]426<!-- ======================================================================= -->
427<div class="doc_subsection">
428 <a name="experimental">Experimental features included with this release</a>
429</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]430
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]431<div class="doc_text">
432
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]433<p>The following components of this LLVM release are either untested, known to
434be broken or unreliable, or are in early development. These components should
435not be relied on, and bugs should not be filed against them, but they may be
436useful 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]437components, please contact us on the <a
438href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]439
440<ul>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]441<li>The MSIL, IA64, Alpha, SPU, and MIPS backends are experimental.</li>
Chris Lattner000c73b2008-02-06 06:30:34 +0000[diff] [blame]442<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
443 value for this option.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]444</ul>
445
446</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]447
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]448<!-- ======================================================================= -->
449<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]450 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]451</div>
452
453<div class="doc_text">
454
455<ul>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]456 <li>The X86 backend does not yet support
457 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
458 floating point stack</a>. It supports the 'f' and 't' constraints, but not
459 'u'.</li>
460 <li>The X86 backend generates inefficient floating point code when configured to
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]461 generate code for systems that don't have SSE2.</li>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]462 <li>Win64 codegeneration wasn't widely tested. Everything should work, but we
463 expect small issues to happen. Also, llvm-gcc cannot build mingw64 runtime
464 currently due
465 to <a href="http://llvm.org/PR2255">several</a>
466 <a href="http://llvm.org/PR2257">bugs</a> in FP stackifier
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]467</ul>
468
469</div>
470
471<!-- ======================================================================= -->
472<div class="doc_subsection">
473 <a name="ppc-be">Known problems with the PowerPC back-end</a>
474</div>
475
476<div class="doc_text">
477
478<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000[diff] [blame]479<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]480compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]481</ul>
482
483</div>
484
485<!-- ======================================================================= -->
486<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]487 <a name="arm-be">Known problems with the ARM back-end</a>
488</div>
489
490<div class="doc_text">
491
492<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]493<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000[diff] [blame]494processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]495results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]496<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
497</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]498<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]499programs compiled with LLVM. Please use more recent versions of QEMU.</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]500</ul>
501
502</div>
503
504<!-- ======================================================================= -->
505<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]506 <a name="sparc-be">Known problems with the SPARC back-end</a>
507</div>
508
509<div class="doc_text">
510
511<ul>
512<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
513 support the 64-bit SPARC ABI (-m64).</li>
514</ul>
515
516</div>
517
518<!-- ======================================================================= -->
519<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]520 <a name="alpha-be">Known problems with the Alpha back-end</a>
521</div>
522
523<div class="doc_text">
524
525<ul>
526
527<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
528appropriate nops inserted to ensure restartability.</li>
529
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]530</ul>
531</div>
532
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]533<!-- ======================================================================= -->
534<div class="doc_subsection">
535 <a name="ia64-be">Known problems with the IA64 back-end</a>
536</div>
537
538<div class="doc_text">
539
540<ul>
541
542<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
543made where the argument is not 16-byte aligned, as required on IA64. (Strictly
544speaking this is not a bug in the IA64 back-end; it will also be encountered
545when building C++ programs using the C back-end.)</li>
546
547<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
548ABI compliant layout of v-tables</a>. In particular, it just stores function
549pointers instead of function descriptors in the vtable. This bug prevents
550mixing C++ code compiled with LLVM with C++ objects compiled by other C++
551compilers.</li>
552
553<li>There are a few ABI violations which will lead to problems when mixing LLVM
554output with code built with other compilers, particularly for floating-point
555programs.</li>
556
557<li>Defining vararg functions is not supported (but calling them is ok).</li>
558
Chris Lattnercaf06342007-05-09 04:58:11 +0000[diff] [blame]559<li>The Itanium backend has bitrotted somewhat.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]560</ul>
561
562</div>
563
564<!-- ======================================================================= -->
565<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]566 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]567</div>
568
569<div class="doc_text">
570
571<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]572<li><a href="http://llvm.org/PR802">The C backend has only basic support for
573 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000[diff] [blame]574<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
575 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
576 C++ code compiled with LLC or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]577<li>The C backend does not support all exception handling constructs.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]578</ul>
579
580</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]581
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]582
583<!-- ======================================================================= -->
584<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]585 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]586</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]587
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]588<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]589<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]590
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]591<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]592
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]593<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
594Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]595llvmdev mailing list if you are interested.</p>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]596
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]597<p>The only major language feature of GCC not supported by llvm-gcc is
598 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
599 are only supported on some targets. For example, trampolines are only
600 supported on some targets, which are used when you take the address of a
601 nested function.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]602
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]603<p>If you run into GCC extensions which are not supported, please let us know.
604</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]605
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]606</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]607
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]608<!-- ======================================================================= -->
609<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]610 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]611</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]612
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]613<div class="doc_text">
614
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]615<p>The C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]616tested and works for a number of non-trivial programs, including LLVM
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]617itself, Qt, Mozilla, etc.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]618
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]619<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]620<li>Exception handling works well on the X86 and PowerPC targets, including
621x86-64 darwin. This works when linking to a libstdc++ compiled by GCC. It is
622supported on x86-64 linux, but that is disabled by default in this release.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]623</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]624
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]625</div>
626
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]627
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]628<!-- ======================================================================= -->
629<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]630 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]631</div>
632
633<div class="doc_text">
634The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
635technology and problems should be expected.
636<ul>
637<li>The Ada front-end currently only builds on x86-32. This is mainly due
638to lack of trampoline support (pointers to nested functions) on other platforms,
639however it <a href="http://llvm.org/PR2006">also fails to build on x86-64</a>
640which does support trampolines.</li>
641<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
642Workaround: configure with --disable-bootstrap.</li>
643<li>The c380004 and <a href="http://llvm.org/PR2010">c393010</a> ACATS tests
644fail (c380004 also fails with gcc-4.2 mainline).</li>
645<li>Many gcc specific Ada tests continue to crash the compiler.</li>
646<li>The -E binder option (exception backtraces)
647<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
648crashing if an exception is raised. Workaround: do not use -E.</li>
649<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
650or finish at a non-byte offset</a> in a record. Workaround: do not pack records
651or use representation clauses that result in a field of a non-discrete type
652starting or finishing in the middle of a byte.</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]653<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers 'main'
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]654as generated by the Ada binder to be invalid</a>.
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]655Workaround: 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]656integers.</li>
Gabor Greif96a89c72008-06-05 18:39:01 +0000[diff] [blame]657<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]658</ul>
659</div>
660
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]661<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]662<div class="doc_section">
663 <a name="additionalinfo">Additional Information</a>
664</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]665<!-- *********************************************************************** -->
666
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]667<div class="doc_text">
668
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]669<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]670href="http://llvm.org">LLVM web page</a>, in particular in the <a
671href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]672contains versions of the API documentation which is up-to-date with the
673Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]674You can access versions of these documents specific to this release by going
675into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]676
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]677<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]678us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]679lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]680
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]681</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]682
683<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]684
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]685<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]686<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]687 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]688 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
689 <a href="http://validator.w3.org/check/referer"><img
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]690 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]691
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]692 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]693 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]694</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]695
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]696</body>
697</html>