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Chris Lattnerd8b33e02008-10-11 18:18:28 +00007 <title>LLVM 2.4 Release Notes</title>
Misha Brukman80731b92003-11-22 00:38:41 +00008</head>
9<body>
Chris Lattner3d482502003-10-02 04:57:28 +000010
Chris Lattnerd8b33e02008-10-11 18:18:28 +000011<div class="doc_title">LLVM 2.4 Release Notes</div>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +000012
Chris Lattner3d482502003-10-02 04:57:28 +000013<ol>
Misha Brukman80731b92003-11-22 00:38:41 +000014 <li><a href="#intro">Introduction</a></li>
Chris Lattnerf5cd9862008-10-13 18:01:01 +000015 <li><a href="#subproj">Sub-project Status Update</a></li>
16 <li><a href="#whatsnew">What's New in LLVM?</a></li>
Chris Lattner77a51732004-04-30 22:17:12 +000017 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +000018 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +000019 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman80731b92003-11-22 00:38:41 +000020 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +000021</ol>
22
Chris Lattner020e1fc2004-05-23 21:07:27 +000023<div class="doc_author">
Chris Lattnera69595e2005-10-29 07:07:09 +000024 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
Misha Brukman80731b92003-11-22 00:38:41 +000025</div>
Chris Lattner3d482502003-10-02 04:57:28 +000026
27<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +000028<div class="doc_section">
29 <a name="intro">Introduction</a>
30</div>
Chris Lattner3d482502003-10-02 04:57:28 +000031<!-- *********************************************************************** -->
32
Misha Brukman80731b92003-11-22 00:38:41 +000033<div class="doc_text">
34
Chris Lattner1e4d5bc2008-10-13 17:57:36 +000035<p>This document contains the release notes for the LLVM Compiler
36Infrastructure, release 2.4. Here we describe the status of LLVM, including
37major improvements from the previous release and significant known problems.
38All LLVM releases may be downloaded from the <a
39href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner62495762003-10-02 16:38:05 +000040
Chris Lattnerb5bb5972004-12-07 08:04:13 +000041<p>For more information about LLVM, including information about the latest
Chris Lattnera69595e2005-10-29 07:07:09 +000042release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattnere7525b52003-10-07 21:38:31 +000043web site</a>. If you have questions or comments, the <a
Chris Lattner1e4d5bc2008-10-13 17:57:36 +000044href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's Mailing
45List</a> is a good place to send them.</p>
Chris Lattner3d482502003-10-02 04:57:28 +000046
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +000047<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner0a1fd102007-09-21 03:54:09 +000048main LLVM web page, this document applies to the <i>next</i> release, not the
49current one. To see the release notes for a specific releases, please see the
50<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman80731b92003-11-22 00:38:41 +000051
52</div>
Chris Lattner3d482502003-10-02 04:57:28 +000053
Chris Lattnerd8b33e02008-10-11 18:18:28 +000054<!-- Unfinished features in 2.4:
Chris Lattner2b8a52e2008-02-10 07:46:44 +000055 Machine LICM
56 Machine Sinking
57 LegalizeDAGTypes
Chris Lattnerc4d68542008-10-12 19:47:48 +000058 llc -enable-value-prop, propagation of value info (sign/zero ext info) from
59 one MBB to another
Chris Lattner2b8a52e2008-02-10 07:46:44 +000060 -->
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +000061
Chris Lattnerc4d68542008-10-12 19:47:48 +000062 <!-- for announcement email:
63 mention dev mtg
Chris Lattnere3df07e2008-10-12 22:57:58 +000064 Xcode 3.1 and 3.1.1.
Chris Lattnerc4d68542008-10-12 19:47:48 +000065 -->
Chris Lattner2b8a52e2008-02-10 07:46:44 +000066
Chris Lattnerf5cd9862008-10-13 18:01:01 +000067<!-- *********************************************************************** -->
68<div class="doc_section">
69 <a name="subproj">Sub-project Status Update</a>
Chris Lattner625a3d82008-06-08 21:34:41 +000070</div>
Chris Lattnerf5cd9862008-10-13 18:01:01 +000071<!-- *********************************************************************** -->
Chris Lattner625a3d82008-06-08 21:34:41 +000072
73<div class="doc_text">
Chris Lattnerc75fd522008-06-08 21:58:17 +000074<p>
Chris Lattnerf5cd9862008-10-13 18:01:01 +000075The LLVM 2.4 distribution currently consists of code from the core LLVM
Chris Lattner44c09cd2008-10-13 18:11:54 +000076repository (which roughly includes the LLVM optimizers, code generators and
Chris Lattnerc75fd522008-06-08 21:58:17 +000077supporting tools) and the llvm-gcc repository. In addition to this code, the
78LLVM Project includes other sub-projects that are in development. The two which
Chris Lattnerd8b33e02008-10-11 18:18:28 +000079are the most actively developed are the <a href="#clang">Clang Project</a> and
Duncan Sandsb34d5902008-10-13 18:33:28 +000080the <a href="#vmkit">vmkit Project</a>.
Chris Lattnerc75fd522008-06-08 21:58:17 +000081</p>
Chris Lattnerf5cd9862008-10-13 18:01:01 +000082
Chris Lattnerc75fd522008-06-08 21:58:17 +000083</div>
84
Chris Lattnerf5cd9862008-10-13 18:01:01 +000085
Chris Lattnerc75fd522008-06-08 21:58:17 +000086<!--=========================================================================-->
Chris Lattnerf5cd9862008-10-13 18:01:01 +000087<div class="doc_subsection">
Chris Lattner44c09cd2008-10-13 18:11:54 +000088<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattnerc75fd522008-06-08 21:58:17 +000089</div>
90
91<div class="doc_text">
92
93<p>The <a href="http://clang.llvm.org/">Clang project</a> is an effort to build
94a set of new 'LLVM native' front-end technologies for the LLVM optimizer
95and code generator. Clang is continuing to make major strides forward in all
96areas. Its C and Objective-C parsing support is very solid, and the code
97generation support is far enough along to build many C applications. While not
98yet production quality, it is progressing very nicely. In addition, C++
99front-end work has started to make significant progress.</p>
100
Chris Lattnerd8b33e02008-10-11 18:18:28 +0000101<p>Codegen progress/state
102</p>
103
Chris Lattner44c09cd2008-10-13 18:11:54 +0000104</div>
105
106<!--=========================================================================-->
107<div class="doc_subsection">
108<a name="clangsa">Clang Static Analyzer</a>
109</div>
110
111<div class="doc_text">
112
113<p>The
Chris Lattnerd8b33e02008-10-11 18:18:28 +0000114<a href="http://clang.llvm.org/StaticAnalysis.html">static analysis tool</a>
Chris Lattner44c09cd2008-10-13 18:11:54 +0000115.</p>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000116
117</div>
118
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000119<!--=========================================================================-->
120<div class="doc_subsection">
Chris Lattner44c09cd2008-10-13 18:11:54 +0000121<a name="vmkit">vmkit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000122</div>
123
124<div class="doc_text">
125<p>
Chris Lattner44c09cd2008-10-13 18:11:54 +0000126The <a href="http://vmkit.llvm.org/">vmkit project</a> is an implementation of
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000127a JVM and a CLI Virtual Machines (Microsoft .NET is an
128implementation of the CLI) using the Just-In-Time compiler of LLVM.</p>
129
130<p>...</p>
131
132</div>
133
Chris Lattnerc75fd522008-06-08 21:58:17 +0000134
135<!-- *********************************************************************** -->
136<div class="doc_section">
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000137 <a name="whatsnew">What's New in LLVM?</a>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000138</div>
139<!-- *********************************************************************** -->
140
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000141<div class="doc_text">
142
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000143<p>This release includes a huge number of bug fixes, performance tweaks and
144minor improvements. Some of the major improvements and new features are listed
145in this section.
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000146</p>
147</div>
148
Chris Lattnerc75fd522008-06-08 21:58:17 +0000149<!--=========================================================================-->
Chris Lattner625a3d82008-06-08 21:34:41 +0000150<div class="doc_subsection">
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000151<a name="majorfeatures">Major New Features</a>
152</div>
153
154<div class="doc_text">
155
Chris Lattnerd8b33e02008-10-11 18:18:28 +0000156<p>LLVM 2.4 includes several major new capabilities:</p>
Chris Lattner97beb512007-05-14 06:56:09 +0000157
158<ul>
Chris Lattnerd8b33e02008-10-11 18:18:28 +0000159<li>
Chris Lattner63969522008-10-12 18:30:33 +0000160 <p>MRVs got generalized to FCAs. getresult is gone, ret with multiple values
161 is gone.</p>
Chris Lattnerd8b33e02008-10-11 18:18:28 +0000162 </li>
163
Chris Lattnerc4d68542008-10-12 19:47:48 +0000164<li><p>-O0 compile times overall much faster</p></li>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000165
Chris Lattnerd8b33e02008-10-11 18:18:28 +0000166<li><p>Attrs changes?</p></li>
Chris Lattner618a99f2008-06-05 06:57:39 +0000167
Chris Lattner63969522008-10-12 18:30:33 +0000168
169<li><p>Initial PIC16 port</p></li>
170
Chris Lattnerc4d68542008-10-12 19:47:48 +0000171<li><p> Support the rest of the atomic __sync builtins</p></li>
Chris Lattner63969522008-10-12 18:30:33 +0000172
Chris Lattnerd8b33e02008-10-11 18:18:28 +0000173<li><p>...</p></li>
Chris Lattner618a99f2008-06-05 06:57:39 +0000174
Chris Lattner458e79f2008-02-10 08:18:42 +0000175</ul>
176
Chris Lattner97beb512007-05-14 06:56:09 +0000177</div>
178
Chris Lattnerb7112222008-06-05 06:25:56 +0000179
180<!--=========================================================================-->
181<div class="doc_subsection">
Chris Lattner625a3d82008-06-08 21:34:41 +0000182<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
Chris Lattnerb7112222008-06-05 06:25:56 +0000183</div>
184
185<div class="doc_text">
186
Chris Lattnerd8b33e02008-10-11 18:18:28 +0000187<p>LLVM 2.4 fully supports the llvm-gcc 4.2 front-end, and includes support
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000188for the C, C++, Objective-C, Ada, and Fortran front-ends.</p>
Chris Lattnerb7112222008-06-05 06:25:56 +0000189
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000190<p>
191<ul>
Duncan Sandsb34d5902008-10-13 18:33:28 +0000192<li>block-pointers<li>
193<li>alpha?<li>
194<li>-flimited-precision</li>
195<li>-flto</li>
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000196
Gabor Greif7f39fb52008-06-09 06:06:18 +0000197</ul>
Chris Lattnerb7112222008-06-05 06:25:56 +0000198
Chris Lattnerb7112222008-06-05 06:25:56 +0000199</div>
200
201
Chris Lattner0a1fd102007-09-21 03:54:09 +0000202<!--=========================================================================-->
203<div class="doc_subsection">
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000204<a name="coreimprovements">LLVM Core Improvements</a>
205</div>
206
207<div class="doc_text">
208<p>New features include:
209</p>
210
Chris Lattnerb7112222008-06-05 06:25:56 +0000211<ul>
Chris Lattnere3df07e2008-10-12 22:57:58 +0000212<li>vector shifts in the IR: no codegen support yet</li>
Chris Lattner63969522008-10-12 18:30:33 +0000213<li>use diet patch landed: saved 15% IR memory footprint</li>
214<li>LLVM IR now directly represents "common" linkage, instead of
215 representing it as a form of weak linkage.</li>
Chris Lattnerc4d68542008-10-12 19:47:48 +0000216<li>DebugInfoBuilder</li>
Chris Lattnere3df07e2008-10-12 22:57:58 +0000217<li>.ll printing format change: %3 = add i32 4, 2</li>
Duncan Sandsb34d5902008-10-13 18:33:28 +0000218<li>opt-size, noinline, alwaysinline function attributes</li>
Chris Lattnerd8b33e02008-10-11 18:18:28 +0000219<li>...</li>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000220</ul>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000221
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000222</div>
223
224<!--=========================================================================-->
225<div class="doc_subsection">
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000226<a name="optimizer">Optimizer Improvements</a>
227</div>
228
229<div class="doc_text">
230
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000231<p>In addition to a huge array of bug fixes and minor performance tweaks, the
Chris Lattnerd8b33e02008-10-11 18:18:28 +0000232LLVM 2.4 optimizers support a few major enhancements:</p>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000233
234<ul>
235
Chris Lattnerc4d68542008-10-12 19:47:48 +0000236<li>GVN now does local PRE?</li>
237
238<li>Matthijs' Dead argument elimination rewrite</li>
239
Chris Lattner63969522008-10-12 18:30:33 +0000240<li>Old-ADCE used control dependence and deleted output-free infinite loops.
241Added a new Loop deletion pass (for deleting output free provably-finite loops)
242and rewrote ADCE to be simpler faster, and not need control dependence.</li>
243
244<li>SparsePropagation framework for lattice-based dataflow solvers.</li>
245
Chris Lattnere3df07e2008-10-12 22:57:58 +0000246<li>Tail duplication was removed from the standard optimizer sequence.</li>
Chris Lattner63969522008-10-12 18:30:33 +0000247
Chris Lattnerc4d68542008-10-12 19:47:48 +0000248<li>Various helper functions (ComputeMaskedBits, ComputeNumSignBits, etc) were
249pulled out of instcombine and put into a new ValueTracking.h file, where they
250can be reused by other passes.</li>
251
Chris Lattnere3df07e2008-10-12 22:57:58 +0000252<li>MarkModRef etc</li>
Chris Lattner7795ea92008-06-08 02:45:07 +0000253</ul>
254
255</div>
256
257<!--=========================================================================-->
258<div class="doc_subsection">
259<a name="codegen">Code Generator Improvements</a>
260</div>
261
262<div class="doc_text">
263
264<p>We put a significant amount of work into the code generator infrastructure,
265which allows us to implement more aggressive algorithms and make it run
266faster:</p>
267
268<ul>
Chris Lattnere3df07e2008-10-12 22:57:58 +0000269<li>asm writers split out to their own library to avoid JITs having to link
270 them in.</li>
271<li>Big asm writer refactoring + TargetAsmInfo</li>
272<li>2-addr pass and coalescer can now remat trivial insts to avoid a copy.</li>
Chris Lattnerc4d68542008-10-12 19:47:48 +0000273<li>spiller to commute instructions in order to fold a reload</li>
274<li>Stack slot coloring?</li>
275<li>Live intervals renumbering? Is this useful to external people?</li>
276<li>'is as cheap as a move' instruction flag</li>
277<li>Improvements to selection dag viewing</li>
278<li>fast isel</li>
Chris Lattnerd8b33e02008-10-11 18:18:28 +0000279<li>Selection dag speedups</li>
Chris Lattnerc4d68542008-10-12 19:47:48 +0000280<li>asmwriter + raw_ostream -> fastah</li>
Chris Lattner3fc6e592008-10-13 17:12:51 +0000281<li>Partitioned Boolean Quadratic Programming (PBQP) based register
282allocator.</li>
Chris Lattnerd8b33e02008-10-11 18:18:28 +0000283<li>...</li>
Chris Lattner7795ea92008-06-08 02:45:07 +0000284
Chris Lattner0a1fd102007-09-21 03:54:09 +0000285</ul>
286
287</div>
288
289
290<!--=========================================================================-->
291<div class="doc_subsection">
Chris Lattner6cb64032008-06-05 08:02:49 +0000292<a name="x86specific">X86/X86-64 Specific Improvements</a>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000293</div>
Chris Lattner727c3742007-05-18 06:33:02 +0000294
Chris Lattner89e761c2006-04-18 06:32:08 +0000295<div class="doc_text">
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000296<p>New target-specific features include:
Chris Lattner97beb512007-05-14 06:56:09 +0000297</p>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000298
299<ul>
Chris Lattnerc4d68542008-10-12 19:47:48 +0000300<li>Exception handling is supported by default on Linux/x86-64.</li>
Duncan Sands719f7782008-10-13 17:32:15 +0000301<li>Position Independent Code (PIC) is now supported on Linux/x86-64.</li>
Chris Lattnerd8b33e02008-10-11 18:18:28 +0000302<li>...</li>
Chris Lattnerb076b002008-06-08 21:19:07 +0000303
Chris Lattner8ce1ba42007-05-17 21:41:31 +0000304</ul>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000305
Chris Lattner8ce1ba42007-05-17 21:41:31 +0000306</div>
Chris Lattner72a269f2006-03-03 00:34:26 +0000307
Chris Lattner0a1fd102007-09-21 03:54:09 +0000308<!--=========================================================================-->
309<div class="doc_subsection">
Chris Lattner6cb64032008-06-05 08:02:49 +0000310<a name="targetspecific">Other Target Specific Improvements</a>
311</div>
312
313<div class="doc_text">
314<p>New target-specific features include:
315</p>
316
317<ul>
Chris Lattnere3df07e2008-10-12 22:57:58 +0000318<li>MIPS floating point support?</li>
Duncan Sands719f7782008-10-13 17:32:15 +0000319<li>PowerPC now supports trampolines.</li>
Chris Lattnerd8b33e02008-10-11 18:18:28 +0000320<li>....</li>
Chris Lattner6cb64032008-06-05 08:02:49 +0000321</ul>
Chris Lattner6cb64032008-06-05 08:02:49 +0000322
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000323</div>
Chris Lattner6cb64032008-06-05 08:02:49 +0000324
325
326<!--=========================================================================-->
327<div class="doc_subsection">
Chris Lattner0a1fd102007-09-21 03:54:09 +0000328<a name="otherimprovements">Other Improvements</a>
329</div>
330
331<div class="doc_text">
332<p>New features include:
333</p>
334
335<ul>
Mikhail Glushenkovd3ec89e2008-10-13 02:46:01 +0000336<li><tt>llvmc2</tt> (the generic compiler driver) gained plugin
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000337 support. It is now easier to experiment with <tt>llvmc2</tt> and
338 build your own tools based on it. </li>
Chris Lattnerc4d68542008-10-12 19:47:48 +0000339<li>raw_ostream + formatting</li>
Chris Lattnere3df07e2008-10-12 22:57:58 +0000340<li>Recycler + pool allocation stuff?</li>
Chris Lattnerd8b33e02008-10-11 18:18:28 +0000341<li>...</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000342</ul>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000343
Chris Lattner0a1fd102007-09-21 03:54:09 +0000344</div>
Chris Lattner72a269f2006-03-03 00:34:26 +0000345
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000346<!--=========================================================================-->
347<div class="doc_subsection">
348<a name="changes">Major Changes and Removed Features</a>
349</div>
350
351<div class="doc_text">
352
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000353<p>If you're already an LLVM user, this section lists some "gotchas" that you
354may run into upgrading from the previous release.</p>
355
Duncan Sandsb34d5902008-10-13 18:33:28 +0000356<p>The LLVM IR generated by llvm-gcc no longer names all instructions.
357 Use the instnamer pass if you want everything named.</p>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000358
Duncan Sandsb34d5902008-10-13 18:33:28 +0000359<li>The LoadVN and GCSE passes have been removed.</li>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000360
361
362<p>LLVM API Changes:</p>
363
364<ul>
365
366<li>... Attributes changes ... </li>
367
368<li>The <tt>DbgStopPointInst</tt> methods <tt>getDirectory</tt> and
369<tt>getFileName</tt> now return <tt>Value*</tt> instead of strings. These can be
370converted to strings using <tt>llvm::GetConstantStringInfo</tt> defined via
371"llvm/Analysis/ValueTracking.h".</li>
372
373<li>API change: BinaryOperator::create -> Create (CmpInst, CastInst too)</li>
374<li>Various header files like "llvm/ADT/iterator" were given a .h suffix.
375 Change your code to #include "llvm/ADT/iterator.h" instead.</li>
376
377</ul>
378
379</div>
380
381
382
Chris Lattner62495762003-10-02 16:38:05 +0000383<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000384<div class="doc_section">
385 <a name="portability">Portability and Supported Platforms</a>
386</div>
Chris Lattner62495762003-10-02 16:38:05 +0000387<!-- *********************************************************************** -->
388
Misha Brukman80731b92003-11-22 00:38:41 +0000389<div class="doc_text">
390
John Criswell64307722004-12-08 20:35:47 +0000391<p>LLVM is known to work on the following platforms:</p>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000392
393<ul>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000394<li>Intel and AMD machines (IA32) running Red Hat Linux, Fedora Core and FreeBSD
Reid Spencer9803b402005-05-17 02:47:27 +0000395 (and probably other unix-like systems).</li>
Chris Lattner7422bce2008-02-06 06:30:34 +0000396<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit and
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000397 64-bit modes.</li>
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000398<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000399<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
400 support is available for native builds with Visual C++).</li>
Gabor Greif80ae8a72008-06-05 18:39:01 +0000401<li>Sun UltraSPARC workstations running Solaris 10.</li>
John Criswelld5234922005-05-13 20:28:15 +0000402<li>Alpha-based machines running Debian GNU/Linux.</li>
Gabor Greif80ae8a72008-06-05 18:39:01 +0000403<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000404</ul>
405
Chris Lattner618a99f2008-06-05 06:57:39 +0000406<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekee3e557e2004-05-09 05:28:35 +0000407to the machine and operating system on which it is built. However, minor
408porting may be required to get LLVM to work on new platforms. We welcome your
409portability patches and reports of successful builds or error messages.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000410
Misha Brukman80731b92003-11-22 00:38:41 +0000411</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000412
413<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000414<div class="doc_section">
415 <a name="knownproblems">Known Problems</a>
416</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000417<!-- *********************************************************************** -->
418
Misha Brukman80731b92003-11-22 00:38:41 +0000419<div class="doc_text">
420
421<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner3d482502003-10-02 04:57:28 +0000422component. As new problems are discovered, they will be added to these
Chris Lattnerb84f3322003-12-12 21:22:16 +0000423sections. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000424href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000425there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000426
Misha Brukman80731b92003-11-22 00:38:41 +0000427</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000428
Chris Lattnerb911de42004-03-14 02:03:02 +0000429<!-- ======================================================================= -->
430<div class="doc_subsection">
431 <a name="experimental">Experimental features included with this release</a>
432</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000433
Chris Lattnerb911de42004-03-14 02:03:02 +0000434<div class="doc_text">
435
Misha Brukmanfa50a222004-05-12 21:46:05 +0000436<p>The following components of this LLVM release are either untested, known to
437be broken or unreliable, or are in early development. These components should
438not be relied on, and bugs should not be filed against them, but they may be
439useful to some people. In particular, if you would like to work on one of these
Chris Lattnere38ac152008-02-12 06:29:45 +0000440components, please contact us on the <a
441href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000442
443<ul>
Chris Lattnere38ac152008-02-12 06:29:45 +0000444<li>The MSIL, IA64, Alpha, SPU, and MIPS backends are experimental.</li>
Duncan Sands56448462008-06-08 20:18:35 +0000445<li>The llc "<tt>-filetype=asm</tt>" (the default) is the only supported
Chris Lattner7422bce2008-02-06 06:30:34 +0000446 value for this option.</li>
Chris Lattnerb911de42004-03-14 02:03:02 +0000447</ul>
448
449</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000450
Misha Brukman80731b92003-11-22 00:38:41 +0000451<!-- ======================================================================= -->
452<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000453 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswell3bdbd302005-11-08 21:11:33 +0000454</div>
455
456<div class="doc_text">
457
458<ul>
Anton Korobeynikov486c7d32008-06-08 10:24:13 +0000459 <li>The X86 backend does not yet support
460 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
461 floating point stack</a>. It supports the 'f' and 't' constraints, but not
462 'u'.</li>
Chris Lattnerb076b002008-06-08 21:19:07 +0000463 <li>The X86 backend generates inefficient floating point code when configured
464 to generate code for systems that don't have SSE2.</li>
Duncan Sands0bc15262008-06-08 19:38:43 +0000465 <li>Win64 code generation wasn't widely tested. Everything should work, but we
Anton Korobeynikov486c7d32008-06-08 10:24:13 +0000466 expect small issues to happen. Also, llvm-gcc cannot build mingw64 runtime
467 currently due
468 to <a href="http://llvm.org/PR2255">several</a>
Chris Lattner54d12102008-06-08 23:12:47 +0000469 <a href="http://llvm.org/PR2257">bugs</a> due to lack of support for the
470 'u' inline assembly constraint and X87 floating point inline assembly.</li>
Dan Gohman721b3722008-06-08 23:05:11 +0000471 <li>The X86-64 backend does not yet support the LLVM IR instruction
472 <tt>va_arg</tt>. Currently, the llvm-gcc front-end supports variadic
473 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000474</ul>
475
476</div>
477
478<!-- ======================================================================= -->
479<div class="doc_subsection">
480 <a name="ppc-be">Known problems with the PowerPC back-end</a>
481</div>
482
483<div class="doc_text">
484
485<ul>
Nicolas Geoffray77d99502007-05-15 09:21:28 +0000486<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattnerbee7b322007-05-23 04:39:32 +0000487compilation, and lacks support for debug information.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000488</ul>
489
490</div>
491
492<!-- ======================================================================= -->
493<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000494 <a name="arm-be">Known problems with the ARM back-end</a>
495</div>
496
497<div class="doc_text">
498
499<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000500<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands47fc0a22007-09-26 15:59:54 +0000501processors, thumb programs can crash or produce wrong
Chris Lattnerbee7b322007-05-23 04:39:32 +0000502results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000503<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
504</li>
Chris Lattnerb076b002008-06-08 21:19:07 +0000505<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly
506 execute
Chris Lattnerbee7b322007-05-23 04:39:32 +0000507programs compiled with LLVM. Please use more recent versions of QEMU.</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000508</ul>
509
510</div>
511
512<!-- ======================================================================= -->
513<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000514 <a name="sparc-be">Known problems with the SPARC back-end</a>
515</div>
516
517<div class="doc_text">
518
519<ul>
520<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
521 support the 64-bit SPARC ABI (-m64).</li>
522</ul>
523
524</div>
525
526<!-- ======================================================================= -->
527<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000528 <a name="alpha-be">Known problems with the Alpha back-end</a>
529</div>
530
531<div class="doc_text">
532
533<ul>
534
535<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
536appropriate nops inserted to ensure restartability.</li>
537
John Criswell3bdbd302005-11-08 21:11:33 +0000538</ul>
539</div>
540
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000541<!-- ======================================================================= -->
542<div class="doc_subsection">
543 <a name="ia64-be">Known problems with the IA64 back-end</a>
544</div>
545
546<div class="doc_text">
547
548<ul>
Chris Lattner54d12102008-06-08 23:12:47 +0000549<li>The Itanium backend is highly experimental, and has a number of known
550 issues. We are looking for a maintainer for the Itanium backend. If you
551 are interested, please contact the llvmdev mailing list.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000552</ul>
553
554</div>
555
556<!-- ======================================================================= -->
557<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000558 <a name="c-be">Known problems with the C back-end</a>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000559</div>
560
561<div class="doc_text">
562
563<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000564<li><a href="http://llvm.org/PR802">The C backend has only basic support for
565 inline assembly code</a>.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000566<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
567 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Duncan Sands56448462008-06-08 20:18:35 +0000568 C++ code compiled with llc or native compilers.</li>
Duncan Sandse09506a2008-02-10 13:40:55 +0000569<li>The C backend does not support all exception handling constructs.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000570</ul>
571
572</div>
John Criswell3bdbd302005-11-08 21:11:33 +0000573
Misha Brukman80731b92003-11-22 00:38:41 +0000574
575<!-- ======================================================================= -->
576<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000577 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000578</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000579
Misha Brukman80731b92003-11-22 00:38:41 +0000580<div class="doc_text">
Chris Lattner72a269f2006-03-03 00:34:26 +0000581
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000582<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
583Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Chris Lattner97beb512007-05-14 06:56:09 +0000584llvmdev mailing list if you are interested.</p>
Chris Lattner44124232006-08-08 17:27:28 +0000585
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000586<p>The only major language feature of GCC not supported by llvm-gcc is
587 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
588 are only supported on some targets. For example, trampolines are only
Duncan Sands56448462008-06-08 20:18:35 +0000589 supported on some targets (these are used when you take the address of a
590 nested function).</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000591
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000592<p>If you run into GCC extensions which are not supported, please let us know.
593</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000594
Misha Brukman80731b92003-11-22 00:38:41 +0000595</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000596
Misha Brukman80731b92003-11-22 00:38:41 +0000597<!-- ======================================================================= -->
598<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000599 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000600</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000601
Misha Brukman80731b92003-11-22 00:38:41 +0000602<div class="doc_text">
603
Chris Lattner97beb512007-05-14 06:56:09 +0000604<p>The C++ front-end is considered to be fully
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000605tested and works for a number of non-trivial programs, including LLVM
Chris Lattner97beb512007-05-14 06:56:09 +0000606itself, Qt, Mozilla, etc.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000607
Misha Brukman80731b92003-11-22 00:38:41 +0000608<ul>
Anton Korobeynikov28f08aa2008-10-11 18:27:16 +0000609<li>Exception handling works well on the X86 and PowerPC targets. Currently
610 only linux and darwin targets are supported (both 32 and 64 bit).</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000611</ul>
Chris Lattner46ecf612003-10-07 22:14:37 +0000612
Misha Brukman80731b92003-11-22 00:38:41 +0000613</div>
614
Misha Brukman80731b92003-11-22 00:38:41 +0000615
Chris Lattnere38ac152008-02-12 06:29:45 +0000616<!-- ======================================================================= -->
617<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000618 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnere38ac152008-02-12 06:29:45 +0000619</div>
620
621<div class="doc_text">
622The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
623technology and problems should be expected.
624<ul>
Duncan Sands56448462008-06-08 20:18:35 +0000625<li>The Ada front-end currently only builds on X86-32. This is mainly due
Chris Lattnere38ac152008-02-12 06:29:45 +0000626to lack of trampoline support (pointers to nested functions) on other platforms,
Duncan Sands56448462008-06-08 20:18:35 +0000627however it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattnere38ac152008-02-12 06:29:45 +0000628which does support trampolines.</li>
629<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
630Workaround: configure with --disable-bootstrap.</li>
Duncan Sandsaef747f2008-10-13 17:27:23 +0000631<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
632and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
633(c380004 also fails with gcc-4.2 mainline).</li>
634<li>Some gcc specific Ada tests continue to crash the compiler.</li>
Chris Lattnere38ac152008-02-12 06:29:45 +0000635<li>The -E binder option (exception backtraces)
636<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
637crashing if an exception is raised. Workaround: do not use -E.</li>
638<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
639or finish at a non-byte offset</a> in a record. Workaround: do not pack records
640or use representation clauses that result in a field of a non-discrete type
641starting or finishing in the middle of a byte.</li>
Chris Lattnerb076b002008-06-08 21:19:07 +0000642<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
643'main' as generated by the Ada binder to be invalid</a>.
644Workaround: hand edit the file to use pointers for <tt>argv</tt> and
645<tt>envp</tt> rather than integers.</li>
646<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
647ignored</a>.</li>
Chris Lattnere38ac152008-02-12 06:29:45 +0000648</ul>
649</div>
650
Chris Lattner3d482502003-10-02 04:57:28 +0000651<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000652<div class="doc_section">
653 <a name="additionalinfo">Additional Information</a>
654</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000655<!-- *********************************************************************** -->
656
Misha Brukman80731b92003-11-22 00:38:41 +0000657<div class="doc_text">
658
Chris Lattnercb5596d2005-05-16 17:13:10 +0000659<p>A wide variety of additional information is available on the <a
Chris Lattnere0c1df42007-05-18 00:44:29 +0000660href="http://llvm.org">LLVM web page</a>, in particular in the <a
661href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencerc7f87f22007-07-09 08:04:31 +0000662contains versions of the API documentation which is up-to-date with the
663Subversion version of the source code.
Misha Brukman96158092005-03-30 19:14:24 +0000664You can access versions of these documents specific to this release by going
665into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000666
Misha Brukman80731b92003-11-22 00:38:41 +0000667<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnera69595e2005-10-29 07:07:09 +0000668us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000669lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000670
Misha Brukman80731b92003-11-22 00:38:41 +0000671</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000672
673<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000674
Misha Brukman80731b92003-11-22 00:38:41 +0000675<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000676<address>
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679 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukman68aab3b2003-11-22 01:23:39 +0000681
Chris Lattnere0c1df42007-05-18 00:44:29 +0000682 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000683 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000684</address>
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687</html>