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Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]7 <title>LLVM 2.4 Release Notes</title>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]8</head>
9<body>
10
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]11<div class="doc_title">LLVM 2.4 Release Notes</div>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]12
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]13<ol>
14 <li><a href="#intro">Introduction</a></li>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]15 <li><a href="#subproj">Sub-project Status Update</a></li>
16 <li><a href="#whatsnew">What's New in LLVM?</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]17 <li><a href="GettingStarted.html">Installation Instructions</a></li>
18 <li><a href="#portability">Portability and Supported Platforms</a></li>
19 <li><a href="#knownproblems">Known Problems</a>
20 <li><a href="#additionalinfo">Additional Information</a></li>
21</ol>
22
23<div class="doc_author">
24 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
25</div>
26
27<!-- *********************************************************************** -->
28<div class="doc_section">
29 <a name="intro">Introduction</a>
30</div>
31<!-- *********************************************************************** -->
32
33<div class="doc_text">
34
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]35<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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]40
41<p>For more information about LLVM, including information about the latest
42release, please check out the <a href="http://llvm.org/">main LLVM
43web site</a>. If you have questions or comments, the <a
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]44href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's Mailing
45List</a> is a good place to send them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]46
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]47<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]48main 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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]51
52</div>
53
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]54<!-- Unfinished features in 2.4:
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]55 Machine LICM
56 Machine Sinking
57 LegalizeDAGTypes
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]58 llc -enable-value-prop, propagation of value info (sign/zero ext info) from
59 one MBB to another
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]60 -->
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]61
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]62 <!-- for announcement email:
63 mention dev mtg
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]64 Xcode 3.1 and 3.1.1.
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]65 -->
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]66
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]67<!-- *********************************************************************** -->
68<div class="doc_section">
69 <a name="subproj">Sub-project Status Update</a>
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]70</div>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]71<!-- *********************************************************************** -->
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]72
73<div class="doc_text">
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]74<p>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]75The LLVM 2.4 distribution currently consists of code from the core LLVM
Chris Lattnera3c683b2008-10-13 18:11:54 +0000[diff] [blame]76repository (which roughly includes the LLVM optimizers, code generators and
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]77supporting 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 Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]79are the most actively developed are the <a href="#clang">Clang Project</a> and
Duncan Sands275d1e02008-10-13 18:33:28 +0000[diff] [blame]80the <a href="#vmkit">vmkit Project</a>.
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]81</p>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]82
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]83</div>
84
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]85
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]86<!--=========================================================================-->
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]87<div class="doc_subsection">
Chris Lattnera3c683b2008-10-13 18:11:54 +0000[diff] [blame]88<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]89</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 Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]101<p>Codegen progress/state
102</p>
103
Chris Lattnera3c683b2008-10-13 18:11:54 +0000[diff] [blame]104</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 Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]114<a href="http://clang.llvm.org/StaticAnalysis.html">static analysis tool</a>
Chris Lattnera3c683b2008-10-13 18:11:54 +0000[diff] [blame]115.</p>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]116
117</div>
118
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]119<!--=========================================================================-->
120<div class="doc_subsection">
Chris Lattnera3c683b2008-10-13 18:11:54 +0000[diff] [blame]121<a name="vmkit">vmkit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]122</div>
123
124<div class="doc_text">
125<p>
Chris Lattnera3c683b2008-10-13 18:11:54 +0000[diff] [blame]126The <a href="http://vmkit.llvm.org/">vmkit project</a> is an implementation of
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]127a 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 Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]134
135<!-- *********************************************************************** -->
136<div class="doc_section">
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]137 <a name="whatsnew">What's New in LLVM?</a>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]138</div>
139<!-- *********************************************************************** -->
140
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]141<div class="doc_text">
142
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]143<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 Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]146</p>
147</div>
148
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000[diff] [blame]149<!--=========================================================================-->
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]150<div class="doc_subsection">
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]151<a name="majorfeatures">Major New Features</a>
152</div>
153
154<div class="doc_text">
155
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]156<p>LLVM 2.4 includes several major new capabilities:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]157
158<ul>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]159<li>
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]160 <p>MRVs got generalized to FCAs. getresult is gone, ret with multiple values
161 is gone.</p>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]162 </li>
163
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]164<li><p>-O0 compile times overall much faster</p></li>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]165
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]166<li><p>Attrs changes?</p></li>
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]167
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]168
169<li><p>Initial PIC16 port</p></li>
170
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]171<li><p> Support the rest of the atomic __sync builtins</p></li>
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]172
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]173<li><p>...</p></li>
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]174
Chris Lattner5ba16862008-02-10 08:18:42 +0000[diff] [blame]175</ul>
176
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]177</div>
178
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]179
180<!--=========================================================================-->
181<div class="doc_subsection">
Chris Lattnerf65224f2008-06-08 21:34:41 +0000[diff] [blame]182<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]183</div>
184
185<div class="doc_text">
186
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]187<p>LLVM 2.4 fully supports the llvm-gcc 4.2 front-end, and includes support
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]188for the C, C++, Objective-C, Ada, and Fortran front-ends.</p>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]189
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]190<p>
191<ul>
Duncan Sands275d1e02008-10-13 18:33:28 +0000[diff] [blame]192<li>block-pointers<li>
193<li>alpha?<li>
194<li>-flimited-precision</li>
195<li>-flto</li>
Chris Lattner5cce7a52008-06-08 22:59:35 +0000[diff] [blame]196
Gabor Greif0e49cc82008-06-09 06:06:18 +0000[diff] [blame]197</ul>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]198
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]199</div>
200
201
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]202<!--=========================================================================-->
203<div class="doc_subsection">
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]204<a name="coreimprovements">LLVM Core Improvements</a>
205</div>
206
207<div class="doc_text">
208<p>New features include:
209</p>
210
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000[diff] [blame]211<ul>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]212<li>vector shifts in the IR: no codegen support yet</li>
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]213<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 Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]216<li>DebugInfoBuilder</li>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]217<li>.ll printing format change: %3 = add i32 4, 2</li>
Duncan Sands275d1e02008-10-13 18:33:28 +0000[diff] [blame]218<li>opt-size, noinline, alwaysinline function attributes</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]219<li>...</li>
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]220</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]221
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]222</div>
223
224<!--=========================================================================-->
225<div class="doc_subsection">
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]226<a name="optimizer">Optimizer Improvements</a>
227</div>
228
229<div class="doc_text">
230
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]231<p>In addition to a huge array of bug fixes and minor performance tweaks, the
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]232LLVM 2.4 optimizers support a few major enhancements:</p>
Chris Lattner8fda4952008-02-10 07:46:44 +0000[diff] [blame]233
234<ul>
235
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]236<li>GVN now does local PRE?</li>
237
238<li>Matthijs' Dead argument elimination rewrite</li>
239
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]240<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 Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]246<li>Tail duplication was removed from the standard optimizer sequence.</li>
Chris Lattnera5a49382008-10-12 18:30:33 +0000[diff] [blame]247
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]248<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
Duncan Sands2aecc3f2008-10-13 18:42:43 +0000[diff] [blame]252<li>The new AddReadAttrs pass works out which functions are read-only or
253read-none (these correspond to 'pure' and 'const' in C) and marks them
254with the appropriate attribute.</li>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]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>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]271<li>asm writers split out to their own library to avoid JITs having to link
272 them in.</li>
273<li>Big asm writer refactoring + TargetAsmInfo</li>
274<li>2-addr pass and coalescer can now remat trivial insts to avoid a copy.</li>
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]275<li>spiller to commute instructions in order to fold a reload</li>
276<li>Stack slot coloring?</li>
277<li>Live intervals renumbering? Is this useful to external people?</li>
278<li>'is as cheap as a move' instruction flag</li>
279<li>Improvements to selection dag viewing</li>
280<li>fast isel</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]281<li>Selection dag speedups</li>
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]282<li>asmwriter + raw_ostream -> fastah</li>
Chris Lattner72c8a252008-10-13 17:12:51 +0000[diff] [blame]283<li>Partitioned Boolean Quadratic Programming (PBQP) based register
284allocator.</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]285<li>...</li>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000[diff] [blame]286
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]287</ul>
288
289</div>
290
291
292<!--=========================================================================-->
293<div class="doc_subsection">
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]294<a name="x86specific">X86/X86-64 Specific Improvements</a>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]295</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]296
297<div class="doc_text">
Chris Lattnerc3649452008-02-10 08:17:19 +0000[diff] [blame]298<p>New target-specific features include:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]299</p>
300
301<ul>
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]302<li>Exception handling is supported by default on Linux/x86-64.</li>
Duncan Sandsd8745a92008-10-13 17:32:15 +0000[diff] [blame]303<li>Position Independent Code (PIC) is now supported on Linux/x86-64.</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]304<li>...</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]305
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]306</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]307
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]308</div>
309
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]310<!--=========================================================================-->
311<div class="doc_subsection">
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]312<a name="targetspecific">Other Target Specific Improvements</a>
313</div>
314
315<div class="doc_text">
316<p>New target-specific features include:
317</p>
318
319<ul>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]320<li>MIPS floating point support?</li>
Duncan Sandsd8745a92008-10-13 17:32:15 +0000[diff] [blame]321<li>PowerPC now supports trampolines.</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]322<li>....</li>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]323</ul>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]324
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]325</div>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000[diff] [blame]326
327
328<!--=========================================================================-->
329<div class="doc_subsection">
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]330<a name="otherimprovements">Other Improvements</a>
331</div>
332
333<div class="doc_text">
334<p>New features include:
335</p>
336
337<ul>
Mikhail Glushenkovcc2d3012008-10-13 02:46:01 +0000[diff] [blame]338<li><tt>llvmc2</tt> (the generic compiler driver) gained plugin
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]339 support. It is now easier to experiment with <tt>llvmc2</tt> and
340 build your own tools based on it. </li>
Chris Lattner4f076402008-10-12 19:47:48 +0000[diff] [blame]341<li>raw_ostream + formatting</li>
Chris Lattner548493b2008-10-12 22:57:58 +0000[diff] [blame]342<li>Recycler + pool allocation stuff?</li>
Chris Lattner2c3ef982008-10-11 18:18:28 +0000[diff] [blame]343<li>...</li>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]344</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]345
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000[diff] [blame]346</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]347
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]348<!--=========================================================================-->
349<div class="doc_subsection">
350<a name="changes">Major Changes and Removed Features</a>
351</div>
352
353<div class="doc_text">
354
Chris Lattner78a130b2008-10-13 18:01:01 +0000[diff] [blame]355<p>If you're already an LLVM user, this section lists some "gotchas" that you
356may run into upgrading from the previous release.</p>
357
Duncan Sands275d1e02008-10-13 18:33:28 +0000[diff] [blame]358<p>The LLVM IR generated by llvm-gcc no longer names all instructions.
359 Use the instnamer pass if you want everything named.</p>
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]360
Duncan Sands275d1e02008-10-13 18:33:28 +0000[diff] [blame]361<li>The LoadVN and GCSE passes have been removed.</li>
Chris Lattner92eacf82008-10-13 17:57:36 +0000[diff] [blame]362
363
364<p>LLVM API Changes:</p>
365
366<ul>
367
368<li>... Attributes changes ... </li>
369
370<li>The <tt>DbgStopPointInst</tt> methods <tt>getDirectory</tt> and
371<tt>getFileName</tt> now return <tt>Value*</tt> instead of strings. These can be
372converted to strings using <tt>llvm::GetConstantStringInfo</tt> defined via
373"llvm/Analysis/ValueTracking.h".</li>
374
375<li>API change: BinaryOperator::create -> Create (CmpInst, CastInst too)</li>
376<li>Various header files like "llvm/ADT/iterator" were given a .h suffix.
377 Change your code to #include "llvm/ADT/iterator.h" instead.</li>
378
379</ul>
380
381</div>
382
383
384
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]385<!-- *********************************************************************** -->
386<div class="doc_section">
387 <a name="portability">Portability and Supported Platforms</a>
388</div>
389<!-- *********************************************************************** -->
390
391<div class="doc_text">
392
393<p>LLVM is known to work on the following platforms:</p>
394
395<ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000[diff] [blame]396<li>Intel and AMD machines (IA32) running Red Hat Linux, Fedora Core and FreeBSD
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]397 (and probably other unix-like systems).</li>
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]398<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]399 64-bit modes.</li>
Chris Lattnere0798082008-02-06 18:00:06 +0000[diff] [blame]400<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]401<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
402 support is available for native builds with Visual C++).</li>
Gabor Greif5e75e652008-06-05 18:39:01 +0000[diff] [blame]403<li>Sun UltraSPARC workstations running Solaris 10.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]404<li>Alpha-based machines running Debian GNU/Linux.</li>
Gabor Greif5e75e652008-06-05 18:39:01 +0000[diff] [blame]405<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]406</ul>
407
Chris Lattnerba948522008-06-05 06:57:39 +0000[diff] [blame]408<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]409to the machine and operating system on which it is built. However, minor
410porting may be required to get LLVM to work on new platforms. We welcome your
411portability patches and reports of successful builds or error messages.</p>
412
413</div>
414
415<!-- *********************************************************************** -->
416<div class="doc_section">
417 <a name="knownproblems">Known Problems</a>
418</div>
419<!-- *********************************************************************** -->
420
421<div class="doc_text">
422
423<p>This section contains all known problems with the LLVM system, listed by
424component. As new problems are discovered, they will be added to these
425sections. If you run into a problem, please check the <a
426href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
427there isn't already one.</p>
428
429</div>
430
431<!-- ======================================================================= -->
432<div class="doc_subsection">
433 <a name="experimental">Experimental features included with this release</a>
434</div>
435
436<div class="doc_text">
437
438<p>The following components of this LLVM release are either untested, known to
439be broken or unreliable, or are in early development. These components should
440not be relied on, and bugs should not be filed against them, but they may be
441useful to some people. In particular, if you would like to work on one of these
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]442components, please contact us on the <a
443href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]444
445<ul>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]446<li>The MSIL, IA64, Alpha, SPU, and MIPS backends are experimental.</li>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]447<li>The llc "<tt>-filetype=asm</tt>" (the default) is the only supported
Chris Lattnerbd633de92008-02-06 06:30:34 +0000[diff] [blame]448 value for this option.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]449</ul>
450
451</div>
452
453<!-- ======================================================================= -->
454<div class="doc_subsection">
455 <a name="x86-be">Known problems with the X86 back-end</a>
456</div>
457
458<div class="doc_text">
459
460<ul>
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000[diff] [blame]461 <li>The X86 backend does not yet support
462 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
463 floating point stack</a>. It supports the 'f' and 't' constraints, but not
464 'u'.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]465 <li>The X86 backend generates inefficient floating point code when configured
466 to generate code for systems that don't have SSE2.</li>
Duncan Sands8b4f3772008-06-08 19:38:43 +0000[diff] [blame]467 <li>Win64 code generation wasn't widely tested. Everything should work, but we
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000[diff] [blame]468 expect small issues to happen. Also, llvm-gcc cannot build mingw64 runtime
469 currently due
470 to <a href="http://llvm.org/PR2255">several</a>
Chris Lattnerf06141a2008-06-08 23:12:47 +0000[diff] [blame]471 <a href="http://llvm.org/PR2257">bugs</a> due to lack of support for the
472 'u' inline assembly constraint and X87 floating point inline assembly.</li>
Dan Gohman3882ecb2008-06-08 23:05:11 +0000[diff] [blame]473 <li>The X86-64 backend does not yet support the LLVM IR instruction
474 <tt>va_arg</tt>. Currently, the llvm-gcc front-end supports variadic
475 argument constructs on X86-64 by lowering them manually.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]476</ul>
477
478</div>
479
480<!-- ======================================================================= -->
481<div class="doc_subsection">
482 <a name="ppc-be">Known problems with the PowerPC back-end</a>
483</div>
484
485<div class="doc_text">
486
487<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]488<li>The Linux PPC32/ABI support needs testing for the interpreter and static
489compilation, and lacks support for debug information.</li>
490</ul>
491
492</div>
493
494<!-- ======================================================================= -->
495<div class="doc_subsection">
496 <a name="arm-be">Known problems with the ARM back-end</a>
497</div>
498
499<div class="doc_text">
500
501<ul>
502<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000[diff] [blame]503processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]504results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
505<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
506</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]507<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly
508 execute
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]509programs compiled with LLVM. Please use more recent versions of QEMU.</li>
510</ul>
511
512</div>
513
514<!-- ======================================================================= -->
515<div class="doc_subsection">
516 <a name="sparc-be">Known problems with the SPARC back-end</a>
517</div>
518
519<div class="doc_text">
520
521<ul>
522<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
523 support the 64-bit SPARC ABI (-m64).</li>
524</ul>
525
526</div>
527
528<!-- ======================================================================= -->
529<div class="doc_subsection">
530 <a name="alpha-be">Known problems with the Alpha back-end</a>
531</div>
532
533<div class="doc_text">
534
535<ul>
536
537<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
538appropriate nops inserted to ensure restartability.</li>
539
540</ul>
541</div>
542
543<!-- ======================================================================= -->
544<div class="doc_subsection">
545 <a name="ia64-be">Known problems with the IA64 back-end</a>
546</div>
547
548<div class="doc_text">
549
550<ul>
Chris Lattnerf06141a2008-06-08 23:12:47 +0000[diff] [blame]551<li>The Itanium backend is highly experimental, and has a number of known
552 issues. We are looking for a maintainer for the Itanium backend. If you
553 are interested, please contact the llvmdev mailing list.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]554</ul>
555
556</div>
557
558<!-- ======================================================================= -->
559<div class="doc_subsection">
560 <a name="c-be">Known problems with the C back-end</a>
561</div>
562
563<div class="doc_text">
564
565<ul>
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]566<li><a href="http://llvm.org/PR802">The C backend has only basic support for
567 inline assembly code</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000[diff] [blame]568<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
569 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]570 C++ code compiled with llc or native compilers.</li>
Duncan Sandsbd0ad6e2008-02-10 13:40:55 +0000[diff] [blame]571<li>The C backend does not support all exception handling constructs.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]572</ul>
573
574</div>
575
576
577<!-- ======================================================================= -->
578<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]579 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]580</div>
581
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]582<div class="doc_text">
583
Chris Lattnere0798082008-02-06 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
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]586llvmdev mailing list if you are interested.</p>
587
Chris Lattner499c07c2008-06-05 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
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]591 supported on some targets (these are used when you take the address of a
592 nested function).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]593
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]594<p>If you run into GCC extensions which are not supported, please let us know.
595</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]596
597</div>
598
599<!-- ======================================================================= -->
600<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]601 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]602</div>
603
604<div class="doc_text">
605
606<p>The C++ front-end is considered to be fully
607tested and works for a number of non-trivial programs, including LLVM
608itself, Qt, Mozilla, etc.</p>
609
610<ul>
Anton Korobeynikovd9a17932008-10-11 18:27:16 +0000[diff] [blame]611<li>Exception handling works well on the X86 and PowerPC targets. Currently
612 only linux and darwin targets are supported (both 32 and 64 bit).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]613</ul>
614
615</div>
616
617
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]618<!-- ======================================================================= -->
619<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000[diff] [blame]620 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]621</div>
622
623<div class="doc_text">
624The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
625technology and problems should be expected.
626<ul>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]627<li>The Ada front-end currently only builds on X86-32. This is mainly due
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]628to lack of trampoline support (pointers to nested functions) on other platforms,
Duncan Sandsa73561c2008-06-08 20:18:35 +0000[diff] [blame]629however it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]630which does support trampolines.</li>
631<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
632Workaround: configure with --disable-bootstrap.</li>
Duncan Sands2dbc2e82008-10-13 17:27:23 +0000[diff] [blame]633<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
634and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
635(c380004 also fails with gcc-4.2 mainline).</li>
636<li>Some gcc specific Ada tests continue to crash the compiler.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]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>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000[diff] [blame]644<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
645'main' as generated by the Ada binder to be invalid</a>.
646Workaround: hand edit the file to use pointers for <tt>argv</tt> and
647<tt>envp</tt> rather than integers.</li>
648<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
649ignored</a>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000[diff] [blame]650</ul>
651</div>
652
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]653<!-- *********************************************************************** -->
654<div class="doc_section">
655 <a name="additionalinfo">Additional Information</a>
656</div>
657<!-- *********************************************************************** -->
658
659<div class="doc_text">
660
661<p>A wide variety of additional information is available on the <a
662href="http://llvm.org">LLVM web page</a>, in particular in the <a
663href="http://llvm.org/docs/">documentation</a> section. The web page also
664contains versions of the API documentation which is up-to-date with the
665Subversion version of the source code.
666You can access versions of these documents specific to this release by going
667into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
668
669<p>If you have any questions or comments about LLVM, please feel free to contact
670us via the <a href="http://llvm.org/docs/#maillist"> mailing
671lists</a>.</p>
672
673</div>
674
675<!-- *********************************************************************** -->
676
677<hr>
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