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Chris Lattner95d25072009-02-25 04:41:31 +00007 <title>LLVM 2.5 Release Notes</title>
Dan Gohmanf17a25c2007-07-18 16:29:46 +00008</head>
9<body>
10
Chris Lattner95d25072009-02-25 04:41:31 +000011<div class="doc_title">LLVM 2.5 Release Notes</div>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +000012
Dan Gohmanf17a25c2007-07-18 16:29:46 +000013<ol>
14 <li><a href="#intro">Introduction</a></li>
Chris Lattner78a130b2008-10-13 18:01:01 +000015 <li><a href="#subproj">Sub-project Status Update</a></li>
Chris Lattnerb2cc5022009-02-26 22:33:38 +000016 <li><a href="#externalproj">External Projects Using LLVM 2.5</a></li>
Chris Lattner78a130b2008-10-13 18:01:01 +000017 <li><a href="#whatsnew">What's New in LLVM?</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000018 <li><a href="GettingStarted.html">Installation Instructions</a></li>
19 <li><a href="#portability">Portability and Supported Platforms</a></li>
Dan Gohman0de549c2008-10-14 16:23:02 +000020 <li><a href="#knownproblems">Known Problems</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000021 <li><a href="#additionalinfo">Additional Information</a></li>
22</ol>
23
24<div class="doc_author">
Dan Gohman0de549c2008-10-14 16:23:02 +000025 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000026</div>
27
28<!-- *********************************************************************** -->
29<div class="doc_section">
30 <a name="intro">Introduction</a>
31</div>
32<!-- *********************************************************************** -->
33
34<div class="doc_text">
35
Chris Lattner92eacf82008-10-13 17:57:36 +000036<p>This document contains the release notes for the LLVM Compiler
Chris Lattner95d25072009-02-25 04:41:31 +000037Infrastructure, release 2.5. Here we describe the status of LLVM, including
Chris Lattner92eacf82008-10-13 17:57:36 +000038major improvements from the previous release and significant known problems.
39All LLVM releases may be downloaded from the <a
40href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000041
42<p>For more information about LLVM, including information about the latest
43release, please check out the <a href="http://llvm.org/">main LLVM
44web site</a>. If you have questions or comments, the <a
Chris Lattner92eacf82008-10-13 17:57:36 +000045href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's Mailing
46List</a> is a good place to send them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000047
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +000048<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattnerb0d6c502007-09-21 03:54:09 +000049main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greif7c65c4f2008-10-14 11:00:32 +000050current one. To see the release notes for a specific release, please see the
Chris Lattnerb0d6c502007-09-21 03:54:09 +000051<a href="http://llvm.org/releases/">releases page</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +000052
53</div>
54
Chris Lattner95d25072009-02-25 04:41:31 +000055<!-- Unfinished features in 2.5:
Chris Lattner8fda4952008-02-10 07:46:44 +000056 Machine LICM
57 Machine Sinking
Chris Lattnera53f4972009-02-25 06:34:50 +000058 target-specific intrinsics
59 gold lto plugin
Chris Lattner56b64702009-02-25 07:32:53 +000060 pre-alloc splitter, strong phi elim
Chris Lattner4f076402008-10-12 19:47:48 +000061 llc -enable-value-prop, propagation of value info (sign/zero ext info) from
62 one MBB to another
Chris Lattnera53f4972009-02-25 06:34:50 +000063 debug info for optimized code
Chris Lattner5c109932009-02-26 07:29:17 +000064 interpreter + libffi
Chris Lattnerb2cc5022009-02-26 22:33:38 +000065 postalloc scheduler: anti dependence breaking, hazard recognizer?
66
Chris Lattner8fda4952008-02-10 07:46:44 +000067 -->
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +000068
Chris Lattner4f076402008-10-12 19:47:48 +000069 <!-- for announcement email:
Chris Lattnera53f4972009-02-25 06:34:50 +000070 -->
Chris Lattner8fda4952008-02-10 07:46:44 +000071
Chris Lattner78a130b2008-10-13 18:01:01 +000072<!-- *********************************************************************** -->
73<div class="doc_section">
74 <a name="subproj">Sub-project Status Update</a>
Chris Lattnerf65224f2008-06-08 21:34:41 +000075</div>
Chris Lattner78a130b2008-10-13 18:01:01 +000076<!-- *********************************************************************** -->
Chris Lattnerf65224f2008-06-08 21:34:41 +000077
78<div class="doc_text">
Chris Lattnerf6a0d382008-06-08 21:58:17 +000079<p>
Chris Lattner95d25072009-02-25 04:41:31 +000080The LLVM 2.5 distribution currently consists of code from the core LLVM
Chris Lattnera3c683b2008-10-13 18:11:54 +000081repository (which roughly includes the LLVM optimizers, code generators and
Chris Lattnerf6a0d382008-06-08 21:58:17 +000082supporting tools) and the llvm-gcc repository. In addition to this code, the
83LLVM Project includes other sub-projects that are in development. The two which
Chris Lattner2c3ef982008-10-11 18:18:28 +000084are the most actively developed are the <a href="#clang">Clang Project</a> and
Nicolas Geoffray2b139382008-10-14 19:23:04 +000085the <a href="#vmkit">VMKit Project</a>.
Chris Lattnerf6a0d382008-06-08 21:58:17 +000086</p>
Chris Lattner78a130b2008-10-13 18:01:01 +000087
Chris Lattnerf6a0d382008-06-08 21:58:17 +000088</div>
89
Chris Lattner78a130b2008-10-13 18:01:01 +000090
Chris Lattnerf6a0d382008-06-08 21:58:17 +000091<!--=========================================================================-->
Chris Lattner78a130b2008-10-13 18:01:01 +000092<div class="doc_subsection">
Chris Lattnera3c683b2008-10-13 18:11:54 +000093<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattnerf6a0d382008-06-08 21:58:17 +000094</div>
95
96<div class="doc_text">
97
98<p>The <a href="http://clang.llvm.org/">Clang project</a> is an effort to build
99a set of new 'LLVM native' front-end technologies for the LLVM optimizer
Chris Lattnerc97507b2009-02-25 05:09:54 +0000100and code generator. While Clang is not included in the LLVM 2.5 release, it
101is continuing to make major strides forward in all areas. Its C and Objective-C
102parsing and code generation support is now very solid. For example, it is
103capable of successfully building many real applications for X86-32 and X86-64,
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000104including <a href="http://wiki.freebsd.org/BuildingFreeBSDWithClang">the FreeBSD
105kernel</a>. C++ is also making <a
Chris Lattnerc97507b2009-02-25 05:09:54 +0000106href="http://clang.llvm.org/cxx_status.html">incredible progress</a>, and work
107on templates has recently started.</p>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000108
Chris Lattnerc97507b2009-02-25 05:09:54 +0000109<p>While Clang is not yet production quality, it is progressing very nicely and
110is quite usable for building many C and Objective-C applications. If you are
111interested in fast compiles and good diagnostics, we encourage you to try it out
Chris Lattnera53f4972009-02-25 06:34:50 +0000112by <a href="http://clang.llvm.org/get_started.html">building from mainline</a>
Chris Lattnerc97507b2009-02-25 05:09:54 +0000113and reporting any issues you hit to the <a
114href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">Clang front-end mailing
115list</a>.</p>
116
117<p>In the LLVM 2.5 time-frame, the Clang team has made many improvements:</p>
Bill Wendling385b0d32008-10-27 09:27:33 +0000118
Daniel Dunbarf3e35782008-10-14 23:25:09 +0000119<ul>
Chris Lattnerc97507b2009-02-25 05:09:54 +0000120<li>Clang now has a new driver, which is focused on providing a GCC-compatible
121 interface.</li>
122<li>The X86-64 ABI is now supported.</li>
123<li>Precompiled header support is now implemented.</li>
124<li>Objective-C support is significantly improved beyond LLVM 2.4, supporting
125 many features, such as Objective-C Garbage Collection.</li>
126<li>Many many bugs are fixed.</li>
Chris Lattnera3c683b2008-10-13 18:11:54 +0000127</div>
128
129<!--=========================================================================-->
130<div class="doc_subsection">
131<a name="clangsa">Clang Static Analyzer</a>
132</div>
133
134<div class="doc_text">
135
Ted Kremeneka0d77d72009-02-27 07:01:32 +0000136<p>Previously announced in the last LLVM release, the Clang project also
137includes an early stage static source code analysis tool for <a
138href="http://clang.llvm.org/StaticAnalysis.html">automatically finding bugs</a>
139in C and Objective-C programs. The tool performs a growing set of checks to find
140bugs that occur on a specific path within a program.</p>
Chris Lattnerc2d84672008-10-14 00:52:49 +0000141
Ted Kremeneka0d77d72009-02-27 07:01:32 +0000142<p>In the LLVM 2.5 time-frame there have been many significant improvements to
143the analyzer's core path simulation engine and machinery for generating
144path-based bug reports to end-users. Particularly noteworthy improvements
145include experimental support for full field-sensitivity and reasoning about heap
146objects as well as an improved value-constraints subengine that does a much
147better job of reasoning about inequality relationships (e.g., <tt>x &gt; 2</tt>)
148between variables and constants.
Ted Kremenek0437b2c2008-10-14 05:14:21 +0000149
Ted Kremeneka0d77d72009-02-27 07:01:32 +0000150<p>The set of checks performed by the static analyzer continue to expand, and
151future plans for the tool include full source-level inter-procedural analysis
152and deeper checks such as buffer overrun detection. There are many opportunities
153to extend and enhance the static analyzer, and anyone interested in working on
154this project is encouraged to get involved!</p>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000155
156</div>
157
Chris Lattner78a130b2008-10-13 18:01:01 +0000158<!--=========================================================================-->
159<div class="doc_subsection">
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000160<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattner78a130b2008-10-13 18:01:01 +0000161</div>
162
163<div class="doc_text">
164<p>
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000165The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
Chris Lattner78a130b2008-10-13 18:01:01 +0000166a JVM and a CLI Virtual Machines (Microsoft .NET is an
167implementation of the CLI) using the Just-In-Time compiler of LLVM.</p>
168
Chris Lattner02408742009-02-25 05:45:05 +0000169<p>Following LLVM 2.5, VMKit has its first release ? that you can find on its
Nicolas Geoffray20cfdd42008-10-15 20:25:04 +0000170<a href="http://vmkit.llvm.org/releases/">webpage</a>. The release includes
171bug fixes, cleanup and new features. The major changes are:</p>
Chris Lattner78a130b2008-10-13 18:01:01 +0000172
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000173<ul>
174
Chris Lattner47bcf612009-02-26 05:20:36 +0000175<li>Ahead of Time compiler: compiles .class files to llvm .bc. VMKit uses this
176functionality to native compile the standard classes (eg java.lang.String).
177Users can compile AOT .class files into dynamic libraries and run them with the
178help of VMKit.</li>
179
180<li>New exception model: the dwarf exception model is very slow for
181exception-intensive applications, so the JVM has had a new implementation of
182exceptions which check at each function call if an exception happened. There is
183a low performance penalty on applications without exceptions, but it is a big
184gain for exception-intensive applications. For example the jack benchmark in
185Spec JVM98 is 6x faster (performance gain of 83%).</li>
186
187<li>New support for OSX/X64, Linux/X64 (with the Boehm GC), Linux/ppc32.</li>
Nicolas Geoffray2b139382008-10-14 19:23:04 +0000188
189</ul>
Chris Lattner78a130b2008-10-13 18:01:01 +0000190</div>
191
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000192<!-- *********************************************************************** -->
193<div class="doc_section">
194 <a name="externalproj">External Projects Using LLVM 2.5</a>
195</div>
196<!-- *********************************************************************** -->
197
198<!--=========================================================================-->
199<div class="doc_subsection">
200<a name="pure">Pure</a>
201</div>
202
203<div class="doc_text">
204<p>
205http://pure-lang.googlecode.com/
206</p>
207
208<p>
209Pure is an algebraic/functional programming language based on term rewriting.
210Programs are collections of equations which are used to evaluate expressions in
211a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
212lexical closures, a hygienic macro system (also based on term rewriting),
213built-in list and matrix support (including list and matrix comprehensions) and
214an easy-to-use C interface. The interpreter uses LLVM as a backend to
215 JIT-compile Pure programs to fast native code.</p>
216
217<p>In addition to the usual algebraic data structures, Pure also has
218MATLAB-style matrices in order to support numeric computations and signal
219processing in an efficient way. Pure is mainly aimed at mathematical
220applications right now, but it has been designed as a general purpose language.
221The dynamic interpreter environment and the C interface make it possible to use
222it as a kind of functional scripting language for many application areas.
223</p>
224</div>
225
226
227<!--=========================================================================-->
228<div class="doc_subsection">
229<a name="ldc">LLVM D Compiler</a>
230</div>
231
232<div class="doc_text">
233<p>
234http://www.dsource.org/projects/ldc
235</p>
236
237<p>
238I'd like to inform that the LDC project (LLVM D
239Compiler) is working with release 2.5 of LLVM. In fact we've required
2402.5 in our trunk since the release was branched.
241The improvements in 2.5 have fixed a lot of problems with LDC, more
242specifically the new inline asm constraints, better debug info
243support, general bugfixes :) and better x86-64 support have allowed
244some major improvements in LDC, getting us much closer to being as
245fully featured as the original DMD compiler from DigitalMars.
246</p>
247</div>
248
Chris Lattner1ad599a2009-02-28 18:58:01 +0000249<!--=========================================================================-->
250<div class="doc_subsection">
251<a name="RoadsendPHP">Roadsend PHP</a>
252</div>
253
254<div class="doc_text">
255<p>http://code.roadsend.com/rphp</p>
256
257<p>Roadsend PHP is using LLVM for code generation. This is an open source
258project.
259</p>
260</div>
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000261
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000262
263<!-- *********************************************************************** -->
264<div class="doc_section">
Chris Lattner78a130b2008-10-13 18:01:01 +0000265 <a name="whatsnew">What's New in LLVM?</a>
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000266</div>
267<!-- *********************************************************************** -->
268
Chris Lattner5cce7a52008-06-08 22:59:35 +0000269<div class="doc_text">
270
Bill Wendling385b0d32008-10-27 09:27:33 +0000271<p>This release includes a huge number of bug fixes, performance tweaks, and
Chris Lattner92eacf82008-10-13 17:57:36 +0000272minor improvements. Some of the major improvements and new features are listed
273in this section.
Chris Lattner5cce7a52008-06-08 22:59:35 +0000274</p>
275</div>
276
Chris Lattnerf6a0d382008-06-08 21:58:17 +0000277<!--=========================================================================-->
Chris Lattnerf65224f2008-06-08 21:34:41 +0000278<div class="doc_subsection">
Chris Lattnere0798082008-02-06 18:00:06 +0000279<a name="majorfeatures">Major New Features</a>
280</div>
281
282<div class="doc_text">
283
Chris Lattner95d25072009-02-25 04:41:31 +0000284<p>LLVM 2.5 includes several major new capabilities:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000285
286<ul>
Duncan Sandse2cd8182009-02-25 11:37:39 +0000287<li><p>The code generator now supports arbitrary precision integers.
288Types like <tt>i33</tt> have long been valid in the LLVM IR, but previously
289could only be used with the interpreter.
290Now IR using such types can be compiled to native code on all targets.
291All operations are supported if the integer is not bigger than twice the
292target machine word size.
293Simple operations like loads, stores and shifts by a constant amount are
294supported for integers of any size.
295</p></li>
Chris Lattnera53f4972009-02-25 06:34:50 +0000296
297<!--
298Random stuff:
299
Chris Lattner5c109932009-02-26 07:29:17 +0000300Pure project: http://code.google.com/p/pure-lang/
301
302
Chris Lattner56b64702009-02-25 07:32:53 +0000303xcore backend!
304fortran on darwin!
305
Chris Lattner5c109932009-02-26 07:29:17 +0000306.ll parser rewrite, caret diags, better errors, less fragile (less likely to
307 crash on strange things). No longer depends on flex/bison.
Chris Lattnera79cc152009-02-26 06:47:09 +0000308GCC inliner off, llvm handles always-inline.
Chris Lattnera53f4972009-02-25 06:34:50 +0000309cmake mature?
Chris Lattner5c109932009-02-26 07:29:17 +0000310x86 backend GS segment -> addr space 256 (r62980)
Chris Lattnera53f4972009-02-25 06:34:50 +0000311nocapture
Chris Lattnera79cc152009-02-26 06:47:09 +0000312memdep (used by GVN and memcpyopt) is faster / more aggressive.
Chris Lattner56b64702009-02-25 07:32:53 +0000313how to write a backend doc docs/WritingAnLLVMBackend.html
Chris Lattnera53f4972009-02-25 06:34:50 +0000314fastisel + exception handling
315vector widening <3 x float> -> <4 x float>
Chris Lattner56b64702009-02-25 07:32:53 +0000316arm port improvements? arm jit encoding stuff, constant island support?
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000317JIT TLS support on x86-32 but not x86-64.
Chris Lattner56b64702009-02-25 07:32:53 +0000318mem2reg now faster on code with huge basic blocks
319stack protectors/stack canaries, -fstack-protector, controllable on a
320 per-function basis with attributes.
321shufflevector is generalized to allow different shuffle mask width than its
322 input vectors.
323loop optimizer improves floating point induction variables
324llvm/Analysis/DebugInfo.h classes, llvm-gcc and clang and codegen use them.
Chris Lattner5c109932009-02-26 07:29:17 +0000325 DebugInfoBuilder gone.
Chris Lattner56b64702009-02-25 07:32:53 +0000326asmprinters seperate from targets for jits
Chris Lattner47bcf612009-02-26 05:20:36 +0000327PBQP register allocator now supports register coalescing.
Chris Lattnerb2cc5022009-02-26 22:33:38 +0000328JIT supports exceptions on linux/x86-64 and linux/x86-64.
Chris Lattnera79cc152009-02-26 06:47:09 +0000329integer overflow intrinsics for [us](add/sub/mul). Supported on all targets,
330 but only generates efficient code on x86.
331X86 backend now supports -disable-mmx.
332noalias attribute on return value indicates that function returns new memory
333 (e.g. malloc).
Chris Lattnera79cc152009-02-26 06:47:09 +0000334llvmc2 renamed to llvmc
335Jump threading more powerful: it is iterative, handles threading based on values
336 with fully redundant and partially redundant loads.
337LSR improvements?
338ARM debug info support?
339unit test framework based on Google Test.
340
341vector shift support + X86 backend.
Chris Lattner5c109932009-02-26 07:29:17 +0000342x86 JIT now detects core i7 and atom, autoconfiguring itself appropriately.
343SROA is more aggressive about promoting unions.
344non-zero __builtin_return_address values on X86.
345x86-64 now uses red zone (unless -mno-red-zone option is specified).
346private linkage.
Chris Lattner47bcf612009-02-26 05:20:36 +0000347
Chris Lattner5c109932009-02-26 07:29:17 +0000348llvm-gcc defaults to -fno-math-errno on all x86 targets.
349
350initial support for debug line numbers when optimization enabled, not useful in
351 2.5 but will be for 2.6.
Chris Lattnera53f4972009-02-25 06:34:50 +0000352-->
Chris Lattnerba948522008-06-05 06:57:39 +0000353
Chris Lattner5ba16862008-02-10 08:18:42 +0000354</ul>
355
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000356</div>
357
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000358
359<!--=========================================================================-->
360<div class="doc_subsection">
Chris Lattnerf65224f2008-06-08 21:34:41 +0000361<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000362</div>
363
364<div class="doc_text">
365
Chris Lattner4352cc82008-10-13 20:47:20 +0000366<p>LLVM fully supports the llvm-gcc 4.2 front-end, which marries the GCC
367front-ends and driver with the LLVM optimizer and code generator. It currently
368includes support for the C, C++, Objective-C, Ada, and Fortran front-ends.</p>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000369
Chris Lattner5cce7a52008-06-08 22:59:35 +0000370<ul>
Chris Lattner95d25072009-02-25 04:41:31 +0000371<li>?</li>
Gabor Greif0e49cc82008-06-09 06:06:18 +0000372</ul>
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000373
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000374</div>
375
376
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000377<!--=========================================================================-->
378<div class="doc_subsection">
Chris Lattnerc3649452008-02-10 08:17:19 +0000379<a name="coreimprovements">LLVM Core Improvements</a>
380</div>
381
382<div class="doc_text">
Bill Wendling385b0d32008-10-27 09:27:33 +0000383<p>New features include:</p>
Chris Lattnerc3649452008-02-10 08:17:19 +0000384
Chris Lattnerc5a4e312008-06-05 06:25:56 +0000385<ul>
Chris Lattner95d25072009-02-25 04:41:31 +0000386<li>?</li>
Chris Lattnerf7bae6d2008-10-13 20:59:32 +0000387
Chris Lattnerc3649452008-02-10 08:17:19 +0000388</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000389
Chris Lattnerc3649452008-02-10 08:17:19 +0000390</div>
391
392<!--=========================================================================-->
393<div class="doc_subsection">
Chris Lattner8fda4952008-02-10 07:46:44 +0000394<a name="optimizer">Optimizer Improvements</a>
395</div>
396
397<div class="doc_text">
398
Chris Lattnerea9c2242008-10-13 21:50:36 +0000399<p>In addition to a huge array of bug fixes and minor performance tweaks, this
400release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner8fda4952008-02-10 07:46:44 +0000401
402<ul>
403
Chris Lattner95d25072009-02-25 04:41:31 +0000404<li>?</li>
Chris Lattnerea9c2242008-10-13 21:50:36 +0000405
Chris Lattner0eef6e42008-06-08 02:45:07 +0000406</ul>
407
408</div>
409
410<!--=========================================================================-->
411<div class="doc_subsection">
412<a name="codegen">Code Generator Improvements</a>
413</div>
414
415<div class="doc_text">
416
Gabor Greifaa53e562008-10-14 11:31:14 +0000417<p>We have put a significant amount of work into the code generator infrastructure,
Chris Lattner0eef6e42008-06-08 02:45:07 +0000418which allows us to implement more aggressive algorithms and make it run
419faster:</p>
420
421<ul>
Duncan Sands335d5e42009-02-25 11:50:08 +0000422<li>The type legalization logic has been completely rewritten, and is now
423more powerful (it supports arbitrary precision integer types for example)
424and hopefully more correct.
425The type legalizer converts operations on types that are not natively
426supported by the target machine into equivalent code sequences that only use
427natively supported types.
428The old type legalizer is still available and will be used if
429<tt>-disable-legalize-types</tt> is passed to <tt>llc</tt>.
430</li>
Chris Lattner95d25072009-02-25 04:41:31 +0000431<li>?</li>
Chris Lattner0eef6e42008-06-08 02:45:07 +0000432
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000433</ul>
434
435</div>
436
437
438<!--=========================================================================-->
439<div class="doc_subsection">
Chris Lattnere1fbd752009-02-26 07:32:11 +0000440<a name="pic16">PIC16 Target Improvements</a>
441</div>
442
443<div class="doc_text">
444<p>New features of the PIC16 target include:
445</p>
446
447<ul>
448<li>Both direct and indirect load/stores work now.</li>
449<li>Logical, bitwise and conditional operations now work for integer data
450types.</li>
451<li>Function calls involving basic types work now.</li>
452<li>Support for integer arrays.</li>
453<li>Compiler can now emit libcalls for operations not support by m/c insns.</li>
454<li>Support for both data and rom address spaces.</li>
455</li>
456</ul>
457
458<p>Things not yet supported:</p>
459
460<ul>
461<li>Floating point.</li>
462<li>Passing/returning aggregate types to/from functions.</li>
463<li>Variable arguments.</li>
464<li>Indirect function calls.</li>
465<li>Interrupts/prgrams.</li>
466<li>Debug info.</li>
467</li>
468</ul>
469
470</div>
471
472
473<!--=========================================================================-->
474<div class="doc_subsection">
475<a name="othertargetspecific">Other Target Specific Improvements</a>
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000476</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000477
478<div class="doc_text">
Chris Lattnerc3649452008-02-10 08:17:19 +0000479<p>New target-specific features include:
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000480</p>
481
482<ul>
Chris Lattner95d25072009-02-25 04:41:31 +0000483<li>?</li>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000484</ul>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000485
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000486</div>
Chris Lattnere45f18b2008-06-05 08:02:49 +0000487
488
489<!--=========================================================================-->
490<div class="doc_subsection">
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000491<a name="otherimprovements">Other Improvements</a>
492</div>
493
494<div class="doc_text">
495<p>New features include:
496</p>
497
498<ul>
Chris Lattner95d25072009-02-25 04:41:31 +0000499<li>?</li>
Tanya Lattnerc79f7542008-11-04 18:40:27 +0000500
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000501</ul>
Mikhail Glushenkov808cd3e2008-10-13 02:08:34 +0000502
Chris Lattnerb0d6c502007-09-21 03:54:09 +0000503</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000504
Chris Lattner92eacf82008-10-13 17:57:36 +0000505<!--=========================================================================-->
506<div class="doc_subsection">
507<a name="changes">Major Changes and Removed Features</a>
508</div>
509
510<div class="doc_text">
511
Chris Lattnercc64a322008-10-13 22:06:31 +0000512<p>If you're already an LLVM user or developer with out-of-tree changes based
Chris Lattner95d25072009-02-25 04:41:31 +0000513on LLVM 2.4, this section lists some "gotchas" that you may run into upgrading
Chris Lattnercc64a322008-10-13 22:06:31 +0000514from the previous release.</p>
Chris Lattner92eacf82008-10-13 17:57:36 +0000515
516<ul>
517
Chris Lattner95d25072009-02-25 04:41:31 +0000518<li>?</li>
Chris Lattnercc64a322008-10-13 22:06:31 +0000519</ul>
520
521
522<p>In addition, many APIs have changed in this release. Some of the major LLVM
523API changes are:</p>
524
525<ul>
Chris Lattner95d25072009-02-25 04:41:31 +0000526<li>?</li>
Devang Patel0e3da1a2008-10-14 20:03:43 +0000527</ul>
Chris Lattner92eacf82008-10-13 17:57:36 +0000528
Chris Lattner95d25072009-02-25 04:41:31 +0000529<li>?</li>
Chris Lattner92eacf82008-10-13 17:57:36 +0000530</ul>
531
532</div>
533
534
535
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000536<!-- *********************************************************************** -->
537<div class="doc_section">
538 <a name="portability">Portability and Supported Platforms</a>
539</div>
540<!-- *********************************************************************** -->
541
542<div class="doc_text">
543
544<p>LLVM is known to work on the following platforms:</p>
545
546<ul>
Chris Lattnerb1ad47c2008-11-10 05:40:34 +0000547<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
548Linux, Fedora Core and FreeBSD (and probably other unix-like systems).</li>
549<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit
550and 64-bit modes.</li>
Chris Lattnere0798082008-02-06 18:00:06 +0000551<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000552<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
553 support is available for native builds with Visual C++).</li>
Gabor Greif5e75e652008-06-05 18:39:01 +0000554<li>Sun UltraSPARC workstations running Solaris 10.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000555<li>Alpha-based machines running Debian GNU/Linux.</li>
Gabor Greif5e75e652008-06-05 18:39:01 +0000556<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000557</ul>
558
Chris Lattnerba948522008-06-05 06:57:39 +0000559<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000560to the machine and operating system on which it is built. However, minor
561porting may be required to get LLVM to work on new platforms. We welcome your
562portability patches and reports of successful builds or error messages.</p>
563
564</div>
565
566<!-- *********************************************************************** -->
567<div class="doc_section">
568 <a name="knownproblems">Known Problems</a>
569</div>
570<!-- *********************************************************************** -->
571
572<div class="doc_text">
573
Chris Lattnerb1ad47c2008-11-10 05:40:34 +0000574<p>This section contains significant known problems with the LLVM system,
575listed by component. If you run into a problem, please check the <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000576href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
577there isn't already one.</p>
578
579</div>
580
581<!-- ======================================================================= -->
582<div class="doc_subsection">
583 <a name="experimental">Experimental features included with this release</a>
584</div>
585
586<div class="doc_text">
587
588<p>The following components of this LLVM release are either untested, known to
589be broken or unreliable, or are in early development. These components should
590not be relied on, and bugs should not be filed against them, but they may be
591useful to some people. In particular, if you would like to work on one of these
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000592components, please contact us on the <a
593href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000594
595<ul>
Gabor Greifaa53e562008-10-14 11:31:14 +0000596<li>The MSIL, IA64, Alpha, SPU, MIPS, and PIC16 backends are experimental.</li>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000597<li>The llc "<tt>-filetype=asm</tt>" (the default) is the only supported
Chris Lattnerbd633de92008-02-06 06:30:34 +0000598 value for this option.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000599</ul>
600
601</div>
602
603<!-- ======================================================================= -->
604<div class="doc_subsection">
605 <a name="x86-be">Known problems with the X86 back-end</a>
606</div>
607
608<div class="doc_text">
609
610<ul>
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000611 <li>The X86 backend does not yet support
612 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
613 floating point stack</a>. It supports the 'f' and 't' constraints, but not
614 'u'.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000615 <li>The X86 backend generates inefficient floating point code when configured
616 to generate code for systems that don't have SSE2.</li>
Duncan Sands8b4f3772008-06-08 19:38:43 +0000617 <li>Win64 code generation wasn't widely tested. Everything should work, but we
Anton Korobeynikov77d15e22008-06-08 10:24:13 +0000618 expect small issues to happen. Also, llvm-gcc cannot build mingw64 runtime
619 currently due
620 to <a href="http://llvm.org/PR2255">several</a>
Chris Lattnerf06141a2008-06-08 23:12:47 +0000621 <a href="http://llvm.org/PR2257">bugs</a> due to lack of support for the
622 'u' inline assembly constraint and X87 floating point inline assembly.</li>
Dan Gohman3882ecb2008-06-08 23:05:11 +0000623 <li>The X86-64 backend does not yet support the LLVM IR instruction
624 <tt>va_arg</tt>. Currently, the llvm-gcc front-end supports variadic
625 argument constructs on X86-64 by lowering them manually.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000626</ul>
627
628</div>
629
630<!-- ======================================================================= -->
631<div class="doc_subsection">
632 <a name="ppc-be">Known problems with the PowerPC back-end</a>
633</div>
634
635<div class="doc_text">
636
637<ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000638<li>The Linux PPC32/ABI support needs testing for the interpreter and static
639compilation, and lacks support for debug information.</li>
640</ul>
641
642</div>
643
644<!-- ======================================================================= -->
645<div class="doc_subsection">
646 <a name="arm-be">Known problems with the ARM back-end</a>
647</div>
648
649<div class="doc_text">
650
651<ul>
652<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands1827fa62007-09-26 15:59:54 +0000653processors, thumb programs can crash or produce wrong
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000654results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
655<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
656</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000657<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly
658 execute
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000659programs compiled with LLVM. Please use more recent versions of QEMU.</li>
660</ul>
661
662</div>
663
664<!-- ======================================================================= -->
665<div class="doc_subsection">
666 <a name="sparc-be">Known problems with the SPARC back-end</a>
667</div>
668
669<div class="doc_text">
670
671<ul>
672<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
673 support the 64-bit SPARC ABI (-m64).</li>
674</ul>
675
676</div>
677
678<!-- ======================================================================= -->
679<div class="doc_subsection">
Bruno Cardoso Lopes62d45d72008-10-25 14:56:26 +0000680 <a name="mips-be">Known problems with the MIPS back-end</a>
681</div>
682
683<div class="doc_text">
684
685<ul>
686<li>The O32 ABI is not fully supported.</li>
687<li>64-bit MIPS targets are not supported yet.</li>
688</ul>
689
690</div>
691
692<!-- ======================================================================= -->
693<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000694 <a name="alpha-be">Known problems with the Alpha back-end</a>
695</div>
696
697<div class="doc_text">
698
699<ul>
700
701<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
702appropriate nops inserted to ensure restartability.</li>
703
704</ul>
705</div>
706
707<!-- ======================================================================= -->
708<div class="doc_subsection">
709 <a name="ia64-be">Known problems with the IA64 back-end</a>
710</div>
711
712<div class="doc_text">
713
714<ul>
Chris Lattnerf06141a2008-06-08 23:12:47 +0000715<li>The Itanium backend is highly experimental, and has a number of known
716 issues. We are looking for a maintainer for the Itanium backend. If you
Gabor Greif45fc8b12008-10-15 10:47:24 +0000717 are interested, please contact the LLVMdev mailing list.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000718</ul>
719
720</div>
721
722<!-- ======================================================================= -->
723<div class="doc_subsection">
724 <a name="c-be">Known problems with the C back-end</a>
725</div>
726
727<div class="doc_text">
728
729<ul>
Chris Lattner499c07c2008-06-05 06:35:40 +0000730<li><a href="http://llvm.org/PR802">The C backend has only basic support for
731 inline assembly code</a>.</li>
Chris Lattnere0194462007-09-26 06:01:35 +0000732<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
733 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Duncan Sandsa73561c2008-06-08 20:18:35 +0000734 C++ code compiled with llc or native compilers.</li>
Duncan Sandsbd0ad6e2008-02-10 13:40:55 +0000735<li>The C backend does not support all exception handling constructs.</li>
Duncan Sandse6e264c2009-02-25 11:51:54 +0000736<li>The C backend does not support arbitrary precision integers.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000737</ul>
738
739</div>
740
741
742<!-- ======================================================================= -->
743<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000744 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000745</div>
746
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000747<div class="doc_text">
748
Chris Lattnere0798082008-02-06 18:00:06 +0000749<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
750Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Gabor Greif45fc8b12008-10-15 10:47:24 +0000751LLVMdev mailing list if you are interested.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000752
Chris Lattner499c07c2008-06-05 06:35:40 +0000753<p>The only major language feature of GCC not supported by llvm-gcc is
754 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
755 are only supported on some targets. For example, trampolines are only
Duncan Sandsa73561c2008-06-08 20:18:35 +0000756 supported on some targets (these are used when you take the address of a
757 nested function).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000758
Chris Lattner499c07c2008-06-05 06:35:40 +0000759<p>If you run into GCC extensions which are not supported, please let us know.
760</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000761
762</div>
763
764<!-- ======================================================================= -->
765<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000766 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000767</div>
768
769<div class="doc_text">
770
771<p>The C++ front-end is considered to be fully
772tested and works for a number of non-trivial programs, including LLVM
773itself, Qt, Mozilla, etc.</p>
774
775<ul>
Anton Korobeynikovd9a17932008-10-11 18:27:16 +0000776<li>Exception handling works well on the X86 and PowerPC targets. Currently
Chris Lattnerb1ad47c2008-11-10 05:40:34 +0000777 only Linux and Darwin targets are supported (both 32 and 64 bit).</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000778</ul>
779
780</div>
781
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000782<!-- ======================================================================= -->
783<div class="doc_subsection">
784 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
785</div>
786
787<div class="doc_text">
Gabor Greif1fc8fbc2008-11-04 21:50:59 +0000788<ul>
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000789<li>Fortran support generally works, but there are still several unresolved bugs
790 in Bugzilla. Please see the tools/gfortran component for details.</li>
791
792<li>The Fortran front-end currently does not build on Darwin (without tweaks)
793 due to unresolved dependencies on the C front-end.</li>
Gabor Greif1fc8fbc2008-11-04 21:50:59 +0000794</ul>
Chris Lattner6c8a1b82008-10-30 03:58:13 +0000795</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000796
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000797<!-- ======================================================================= -->
798<div class="doc_subsection">
Chris Lattner499c07c2008-06-05 06:35:40 +0000799 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000800</div>
801
802<div class="doc_text">
803The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
804technology and problems should be expected.
805<ul>
Duncan Sandsa73561c2008-06-08 20:18:35 +0000806<li>The Ada front-end currently only builds on X86-32. This is mainly due
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000807to lack of trampoline support (pointers to nested functions) on other platforms,
Duncan Sandsa73561c2008-06-08 20:18:35 +0000808however it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000809which does support trampolines.</li>
810<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
Duncan Sandsf73473e2009-02-25 11:59:06 +0000811This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
812exception handling, which is used internally by the compiler.
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000813Workaround: configure with --disable-bootstrap.</li>
Duncan Sands2dbc2e82008-10-13 17:27:23 +0000814<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
815and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sandsf73473e2009-02-25 11:59:06 +0000816(c380004 also fails with gcc-4.2 mainline).
817If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
818causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sands2dbc2e82008-10-13 17:27:23 +0000819<li>Some gcc specific Ada tests continue to crash the compiler.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000820<li>The -E binder option (exception backtraces)
821<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
822crashing if an exception is raised. Workaround: do not use -E.</li>
823<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
824or finish at a non-byte offset</a> in a record. Workaround: do not pack records
825or use representation clauses that result in a field of a non-discrete type
826starting or finishing in the middle of a byte.</li>
Chris Lattnerd95b5962008-06-08 21:19:07 +0000827<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
828'main' as generated by the Ada binder to be invalid</a>.
829Workaround: hand edit the file to use pointers for <tt>argv</tt> and
830<tt>envp</tt> rather than integers.</li>
831<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
832ignored</a>.</li>
Chris Lattnerdaeb3232008-02-12 06:29:45 +0000833</ul>
834</div>
835
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000836<!-- *********************************************************************** -->
837<div class="doc_section">
838 <a name="additionalinfo">Additional Information</a>
839</div>
840<!-- *********************************************************************** -->
841
842<div class="doc_text">
843
844<p>A wide variety of additional information is available on the <a
845href="http://llvm.org">LLVM web page</a>, in particular in the <a
846href="http://llvm.org/docs/">documentation</a> section. The web page also
847contains versions of the API documentation which is up-to-date with the
848Subversion version of the source code.
849You can access versions of these documents specific to this release by going
850into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
851
852<p>If you have any questions or comments about LLVM, please feel free to contact
853us via the <a href="http://llvm.org/docs/#maillist"> mailing
854lists</a>.</p>
855
856</div>
857
858<!-- *********************************************************************** -->
859
860<hr>
861<address>
862 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000863 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000864 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000865 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000866
867 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
868 Last modified: $Date$
869</address>
870
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872</html>