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Jeffrey Yasskinbec48772010-01-28 01:14:43 +00007 <title>LLVM 2.7 Release Notes</title>
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9<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +000010
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000011<div class="doc_title">LLVM 2.7 Release Notes</div>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +000012
Chris Lattner0e464a92010-03-17 04:02:39 +000013<img align=right src="http://llvm.org/img/DragonSmall.png"
14 width="136" height="136">
15
Chris Lattner79c3fe12003-10-02 04:57:28 +000016<ol>
Misha Brukman500bc302003-11-22 00:38:41 +000017 <li><a href="#intro">Introduction</a></li>
Chris Lattner96a445e2008-10-13 18:01:01 +000018 <li><a href="#subproj">Sub-project Status Update</a></li>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000019 <li><a href="#externalproj">External Projects Using LLVM 2.7</a></li>
20 <li><a href="#whatsnew">What's New in LLVM 2.7?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +000021 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +000022 <li><a href="#portability">Portability and Supported Platforms</a></li>
Dan Gohman44aa9212008-10-14 16:23:02 +000023 <li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +000024 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +000025</ol>
26
Chris Lattner7911ce22004-05-23 21:07:27 +000027<div class="doc_author">
Dan Gohman44aa9212008-10-14 16:23:02 +000028 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Misha Brukman500bc302003-11-22 00:38:41 +000029</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000030
Chris Lattner00736fc2010-04-13 06:37:00 +000031<!--
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000032<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.7
33release.<br>
34You may prefer the
35<a href="http://llvm.org/releases/2.6/docs/ReleaseNotes.html">LLVM 2.6
Chris Lattner00736fc2010-04-13 06:37:00 +000036Release Notes</a>.</h1>-->
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000037
Chris Lattner79c3fe12003-10-02 04:57:28 +000038<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +000039<div class="doc_section">
40 <a name="intro">Introduction</a>
41</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +000042<!-- *********************************************************************** -->
43
Misha Brukman500bc302003-11-22 00:38:41 +000044<div class="doc_text">
45
Chris Lattnerf6662f92008-10-13 17:57:36 +000046<p>This document contains the release notes for the LLVM Compiler
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000047Infrastructure, release 2.7. Here we describe the status of LLVM, including
Chris Lattnerf6662f92008-10-13 17:57:36 +000048major improvements from the previous release and significant known problems.
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +000049All LLVM releases may be downloaded from the <a
Chris Lattnerf6662f92008-10-13 17:57:36 +000050href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +000051
Chris Lattner7506b1d2004-12-07 08:04:13 +000052<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +000053release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +000054web site</a>. If you have questions or comments, the <a
Chris Lattnerc66bfef2010-03-17 04:41:49 +000055href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's
56Mailing List</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +000057
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +000058<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner84977642007-09-21 03:54:09 +000059main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greiffa933f82008-10-14 11:00:32 +000060current one. To see the release notes for a specific release, please see the
Chris Lattner84977642007-09-21 03:54:09 +000061<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +000062
Chris Lattnerc66bfef2010-03-17 04:41:49 +000063
Chris Lattnerdc910082010-03-17 06:41:58 +000064<p>FIXME: llvm.org moved to new server, mention new logo, Ted and Doug new code
Chris Lattner8b5d9c82010-04-16 06:20:22 +000065 owners, web page in llvm-www repos.</p>
Chris Lattnerc66bfef2010-03-17 04:41:49 +000066
Misha Brukman500bc302003-11-22 00:38:41 +000067</div>
Chris Lattner61358ab2009-10-13 17:48:04 +000068
Chris Lattner79c3fe12003-10-02 04:57:28 +000069
Chris Lattner61358ab2009-10-13 17:48:04 +000070<!--
71Almost dead code.
72 include/llvm/Analysis/LiveValues.h => Dan
73 lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8.
74 llvm/Analysis/PointerTracking.h => Edwin wants this, consider for 2.8.
Chris Lattner00736fc2010-04-13 06:37:00 +000075 ABCD, GEPSplitterPass
Chris Lattner048fe3c2010-01-16 21:25:13 +000076 MSIL backend?
Chris Lattnerdc910082010-03-17 06:41:58 +000077 lib/Transforms/Utils/SSI.cpp -> ABCD depends on it.
Chris Lattner61358ab2009-10-13 17:48:04 +000078-->
79
80
Jeffrey Yasskinbec48772010-01-28 01:14:43 +000081<!-- Features that need text if they're finished for 2.7:
Chris Lattner61358ab2009-10-13 17:48:04 +000082 gcc plugin.
83 strong phi elim
84 variable debug info for optimized code
Chris Lattnerab68e9e2009-02-26 22:33:38 +000085 postalloc scheduler: anti dependence breaking, hazard recognizer?
Chris Lattner61358ab2009-10-13 17:48:04 +000086 metadata
87 loop dependence analysis
88 ELF Writer? How stable?
89 <li>PostRA scheduler improvements, ARM adoption (David Goodwin).</li>
Chris Lattneracce85d2008-02-10 07:46:44 +000090 -->
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +000091
Chris Lattner547a3912008-10-12 19:47:48 +000092 <!-- for announcement email:
Chris Lattner61358ab2009-10-13 17:48:04 +000093 Logo web page.
94 llvm devmtg
95 compiler_rt
96 KLEE web page at klee.llvm.org
97 Many new papers added to /pubs/
Chris Lattnerdc910082010-03-17 06:41:58 +000098 Mention gcc plugin.
Chris Lattner74c80df2009-02-25 06:34:50 +000099 -->
Chris Lattneracce85d2008-02-10 07:46:44 +0000100
Chris Lattner96a445e2008-10-13 18:01:01 +0000101<!-- *********************************************************************** -->
102<div class="doc_section">
103 <a name="subproj">Sub-project Status Update</a>
Chris Lattnerea34f642008-06-08 21:34:41 +0000104</div>
Chris Lattner96a445e2008-10-13 18:01:01 +0000105<!-- *********************************************************************** -->
Chris Lattnerea34f642008-06-08 21:34:41 +0000106
107<div class="doc_text">
Chris Lattner8348b472008-06-08 21:58:17 +0000108<p>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000109The LLVM 2.7 distribution currently consists of code from the core LLVM
Chris Lattner61358ab2009-10-13 17:48:04 +0000110repository (which roughly includes the LLVM optimizers, code generators
111and supporting tools), the Clang repository and the llvm-gcc repository. In
112addition to this code, the LLVM Project includes other sub-projects that are in
113development. Here we include updates on these subprojects.
Bill Wendling63d8c552009-03-02 04:28:57 +0000114</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000115
Chris Lattner8348b472008-06-08 21:58:17 +0000116</div>
117
Chris Lattner96a445e2008-10-13 18:01:01 +0000118
Chris Lattner8348b472008-06-08 21:58:17 +0000119<!--=========================================================================-->
Chris Lattner96a445e2008-10-13 18:01:01 +0000120<div class="doc_subsection">
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000121<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000122</div>
123
124<div class="doc_text">
125
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000126<p>The <a href="http://clang.llvm.org/">Clang project</a> is ...</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000127
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000128<p>In the LLVM 2.7 time-frame, the Clang team has made many improvements:</p>
Bill Wendling741748a2008-10-27 09:27:33 +0000129
Daniel Dunbar13739432008-10-14 23:25:09 +0000130<ul>
Daniel Dunbar60dadb62010-03-25 16:09:18 +0000131<li>FIXME: C++! Include a link to cxx_compatibility.html</li>
132
133<li>FIXME: Static Analyzer improvements?</li>
134
135<li>CIndex API and Python bindings: Clang now includes a C API as part of the
136CIndex library. Although we make make some changes to the API in the future, it
137is intended to be stable and has been designed for use by external projects. See
138the Clang
139doxygen <a href="http://clang.llvm.org/doxygen/group__CINDEX.html">CIndex</a>
140documentation for more details. The CIndex API also includings an preliminary
141set of Python bindings.</li>
142
143<li>ARM Support: Clang now has ABI support for both the Darwin and Linux ARM
144ABIs. Coupled with many improvements to the LLVM ARM backend, Clang is now
145suitable for use as a a beta quality ARM compiler.</li>
Bill Wendling6bc15282009-03-02 04:28:18 +0000146</ul>
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000147</div>
148
149<!--=========================================================================-->
150<div class="doc_subsection">
151<a name="clangsa">Clang Static Analyzer</a>
152</div>
153
154<div class="doc_text">
155
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000156<p>Previously announced in the 2.4, 2.5, and 2.6 LLVM releases, the Clang project also
Ted Kremenek8b3894c2009-02-27 07:01:32 +0000157includes an early stage static source code analysis tool for <a
158href="http://clang.llvm.org/StaticAnalysis.html">automatically finding bugs</a>
Chris Lattner61358ab2009-10-13 17:48:04 +0000159in C and Objective-C programs. The tool performs checks to find
Ted Kremenek8b3894c2009-02-27 07:01:32 +0000160bugs that occur on a specific path within a program.</p>
Chris Lattnercc042612008-10-14 00:52:49 +0000161
Chris Lattner0e464a92010-03-17 04:02:39 +0000162<p>In the LLVM 2.7 time-frame, the analyzer core has sprouted legs and...</p>
Chris Lattner8348b472008-06-08 21:58:17 +0000163
164</div>
165
Chris Lattner96a445e2008-10-13 18:01:01 +0000166<!--=========================================================================-->
167<div class="doc_subsection">
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000168<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattner96a445e2008-10-13 18:01:01 +0000169</div>
170
171<div class="doc_text">
172<p>
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000173The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
Chris Lattner61358ab2009-10-13 17:48:04 +0000174a JVM and a CLI Virtual Machine (Microsoft .NET is an
175implementation of the CLI) using LLVM for static and just-in-time
176compilation.</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000177
Chris Lattner61358ab2009-10-13 17:48:04 +0000178<p>
Chris Lattnerbf8e5162010-03-29 18:34:13 +0000179With the release of LLVM 2.7, VMKit has shifted to a great framework for writing
180virtual machines. VMKit now offers precise and efficient garbage collection with
181multi-threading support, thanks to the MMTk memory management toolkit, as well
182as just in time and ahead of time compilation with LLVM. The major changes in
183VMKit 0.27 are:</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000184
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000185<ul>
186
Chris Lattnerbf8e5162010-03-29 18:34:13 +0000187<li>Garbage collection: VMKit now uses the MMTk toolkit for garbage collectors.
188 The first collector to be ported is the MarkSweep collector, which is precise,
189 and drastically improves the performance of VMKit.</li>
190<li>Line number information in the JVM: by using the debug metadata of LLVM, the
191 JVM now supports precise line number information, useful when printing a stack
192 trace.</li>
193<li>Interface calls in the JVM: we implemented a variant of the Interface Method
194 Table technique for interface calls in the JVM.
195</li>
Nicolas Geoffray99a4d302008-10-14 19:23:04 +0000196
197</ul>
Chris Lattner96a445e2008-10-13 18:01:01 +0000198</div>
199
Chris Lattner61358ab2009-10-13 17:48:04 +0000200
201<!--=========================================================================-->
202<div class="doc_subsection">
203<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
204</div>
205
206<div class="doc_text">
207<p>
208The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
209is a simple library that provides an implementation of the low-level
210target-specific hooks required by code generation and other runtime components.
211For example, when compiling for a 32-bit target, converting a double to a 64-bit
212unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
213function. The compiler-rt library provides highly optimized implementations of
214this and other low-level routines (some are 3x faster than the equivalent
215libgcc routines).</p>
216
217<p>
218All of the code in the compiler-rt project is available under the standard LLVM
219License, a "BSD-style" license.</p>
220
221</div>
222
223<!--=========================================================================-->
224<div class="doc_subsection">
Duncan Sands749fd832010-04-02 09:23:15 +0000225<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
Chris Lattner61358ab2009-10-13 17:48:04 +0000226</div>
227
228<div class="doc_text">
229<p>
Duncan Sands749fd832010-04-02 09:23:15 +0000230<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
231gcc-4.5. Unlike llvm-gcc, which makes many intrusive changes to the underlying
232gcc-4.2 code, dragonegg in theory does not require any gcc-4.5 modifications
233whatsoever (currently one small patch is needed). This is thanks to the new
234<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>, which
235makes it possible to modify the behaviour of gcc at runtime by loading a plugin,
236which is nothing more than a dynamic library which conforms to the gcc plugin
237interface. DragonEgg is a gcc plugin that causes the LLVM optimizers to be run
238instead of the gcc optimizers, and the LLVM code generators instead of the gcc
239code generators, just like llvm-gcc. To use it, you add
240"-fplugin=path/dragonegg.so" to the gcc-4.5 command line, and gcc-4.5 magically
241becomes llvm-gcc-4.5!
242</p>
243
244<p>
245DragonEgg is still a work in progress. Currently C works very well, while C++,
246Ada and Fortran work fairly well. All other languages either don't work at all,
247or only work poorly. For the moment only the x86-32 and x86-64 targets are
Duncan Sands51a51742010-04-20 19:40:58 +0000248supported, and only on linux and darwin (darwin needs an additional gcc patch).
Duncan Sands749fd832010-04-02 09:23:15 +0000249</p>
250
251<p>
Duncan Sands51a51742010-04-20 19:40:58 +0000252The first dragonegg release will occur shortly after llvm-2.7 is released.
Chris Lattner61358ab2009-10-13 17:48:04 +0000253</p>
254
255</div>
256
257
258<!--=========================================================================-->
259<div class="doc_subsection">
260<a name="mc">llvm-mc: Machine Code Toolkit</a>
261</div>
262
263<div class="doc_text">
264<p>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000265The LLVM Machine Code (MC) Toolkit project is ...
Chris Lattner61358ab2009-10-13 17:48:04 +0000266</p>
267
268</div>
269
270
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000271<!-- *********************************************************************** -->
272<div class="doc_section">
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000273 <a name="externalproj">External Open Source Projects Using LLVM 2.7</a>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000274</div>
275<!-- *********************************************************************** -->
276
Chris Lattner61358ab2009-10-13 17:48:04 +0000277<div class="doc_text">
278
279<p>An exciting aspect of LLVM is that it is used as an enabling technology for
280 a lot of other language and tools projects. This section lists some of the
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000281 projects that have already been updated to work with LLVM 2.7.</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000282</div>
283
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000284<!--=========================================================================-->
285<div class="doc_subsection">
286<a name="pure">Pure</a>
287</div>
288
289<div class="doc_text">
290<p>
Chris Lattner917cc712009-03-02 02:37:32 +0000291<a href="http://pure-lang.googlecode.com/">Pure</a>
292is an algebraic/functional programming language based on term rewriting.
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000293Programs are collections of equations which are used to evaluate expressions in
294a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000295lexical closures, a hygienic macro system (also based on term rewriting),
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000296built-in list and matrix support (including list and matrix comprehensions) and
297an easy-to-use C interface. The interpreter uses LLVM as a backend to
298 JIT-compile Pure programs to fast native code.</p>
299
Chris Lattner477a1fd2010-03-17 17:25:49 +0000300<p>Pure versions 0.43 and later have been tested and are known to work with
301LLVM 2.7 (and continue to work with older LLVM releases >= 2.5).</p>
302
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000303</div>
304
Chris Lattnerbc31caf2009-02-28 18:58:01 +0000305<!--=========================================================================-->
306<div class="doc_subsection">
307<a name="RoadsendPHP">Roadsend PHP</a>
308</div>
309
310<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000311<p>
312<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
Chris Lattnercade8222009-03-02 19:07:24 +0000313source implementation of the PHP programming
Chris Lattner61358ab2009-10-13 17:48:04 +0000314language that uses LLVM for its optimizer, JIT and static compiler. This is a
Chris Lattner0e464a92010-03-17 04:02:39 +0000315reimplementation of an earlier project that is now based on LLVM.
Chris Lattner477a1fd2010-03-17 17:25:49 +0000316</p>
Chris Lattnerbc31caf2009-02-28 18:58:01 +0000317</div>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000318
Chris Lattner61358ab2009-10-13 17:48:04 +0000319<!--=========================================================================-->
320<div class="doc_subsection">
321<a name="UnladenSwallow">Unladen Swallow</a>
322</div>
323
324<div class="doc_text">
325<p>
326<a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
327branch of <a href="http://python.org/">Python</a> intended to be fully
328compatible and significantly faster. It uses LLVM's optimization passes and JIT
Chris Lattnerb5f6feb2010-03-18 06:52:15 +0000329compiler.
Chris Lattner0e464a92010-03-17 04:02:39 +0000330</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000331</div>
332
333<!--=========================================================================-->
334<div class="doc_subsection">
Chris Lattner8d4bbbe2010-03-29 17:50:39 +0000335<a name="tce">TTA-based Codesign Environment (TCE)</a>
336</div>
337
338<div class="doc_text">
339<p>
340<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing
341application-specific processors (ASP) based on the Transport triggered
342architecture (TTA). The toolset provides a complete co-design flow from C/C++
343programs down to synthesizable VHDL and parallel program binaries. Processor
344customization points include the register files, function units, supported
345operations, and the interconnection network.</p>
346
347<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target
348independent optimizations and also for parts of code generation. It generates
349new LLVM-based code generators "on the fly" for the designed TTA processors and
350loads them in to the compiler backend as runtime libraries to avoid per-target
351recompilation of larger parts of the compiler chain.</p>
352
353</div>
Chris Lattner8348b472008-06-08 21:58:17 +0000354
John Criswellf77cdab2010-04-06 14:52:14 +0000355<!--=========================================================================-->
356<div class="doc_subsection">
357<a name="safecode">SAFECode Compiler</a>
358</div>
359
360<div class="doc_text">
361<p>
362<a href="http://safecode.cs.illinois.edu">SAFECode</a> is a memory safe C
363compiler built using LLVM. It takes standard, unannotated C code, analyzes the
364code to ensure that memory accesses and array indexing operations are safe, and
365instruments the code with run-time checks when safety cannot be proven
366statically.
367</p>
368</div>
369
370
Chris Lattner8348b472008-06-08 21:58:17 +0000371<!-- *********************************************************************** -->
372<div class="doc_section">
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000373 <a name="whatsnew">What's New in LLVM 2.7?</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000374</div>
375<!-- *********************************************************************** -->
376
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000377<div class="doc_text">
378
Chris Lattner61358ab2009-10-13 17:48:04 +0000379<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattnerf6662f92008-10-13 17:57:36 +0000380minor improvements. Some of the major improvements and new features are listed
381in this section.
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000382</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000383
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000384</div>
385
Chris Lattner8348b472008-06-08 21:58:17 +0000386<!--=========================================================================-->
Chris Lattnerea34f642008-06-08 21:34:41 +0000387<div class="doc_subsection">
Chris Lattner252b83d2008-02-06 18:00:06 +0000388<a name="majorfeatures">Major New Features</a>
389</div>
390
391<div class="doc_text">
392
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000393<p>LLVM 2.7 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000394
395<ul>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000396<li>...</li>
Chris Lattner8170c102008-02-10 08:18:42 +0000397</ul>
398
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000399Extensible metadata solid.
400
401Debug info improvements: using metadata instead of llvm.dbg global variables.
402This brings several enhancements including improved compile times.
403
404New instruction selector.
405GHC Haskell ABI/ calling conv support.
406Pre-Alpha support for unions in IR.
407New InlineHint and StackAlignment function attributes
408Code generator MC'ized except for debug info and EH.
409New SCEV AA pass: -scev-aa
410Inliner reuses arrays allocas when inlining multiple callers to reduce stack usage.
411MC encoding and disassembler apis.
412Optimal Edge Profiling?
413Instcombine is now a library, has its own IRBuilder to simplify itself.
414New llvm/Support/Regex.h API. FileCheck now does regex's
Chris Lattnerdc910082010-03-17 06:41:58 +0000415Many subtle pointer invalidation bugs in Callgraph have been fixed and it now uses asserting value handles.
416MC Disassembler (with blog post), MCInstPrinter. Many X86 backend and AsmPrinter simplifications
417Various tools like llc and opt now read either .ll or .bc files as input.
Chris Lattner8e7f1b12010-03-29 18:42:42 +0000418Malloc and free instructions got removed, along with LowerAllocations pass.
Chris Lattnerdc910082010-03-17 06:41:58 +0000419compiler-rt support for ARM.
420completely llvm-gcc NEON support.
421Can transcode from GAS to intel syntax with "llvm-mc foo.s -output-asm-variant=1"
422JIT debug information with GDB 7.0
Chris Lattnerf04bdc52010-03-17 18:15:52 +0000423New CodeGen Level CSE
Chris Lattnerdc910082010-03-17 06:41:58 +0000424CMake can now run tests, what other improvements?
Chris Lattnerf04bdc52010-03-17 18:15:52 +0000425ARM/Thumb using reg scavenging for stack object address materialization (PEI).
Chris Lattnerdc910082010-03-17 06:41:58 +0000426New SSAUpdater and MachineSSAUpdater classes for unstructured ssa updating,
427 changed jump threading, GVN, etc to use it which simplified them and speed
428 them up.
Chris Lattner15a06112010-03-17 06:42:25 +0000429Combiner-AA improvements, why not on by default?
Chris Lattnerf04bdc52010-03-17 18:15:52 +0000430Pre-regalloc tail duplication
Chris Lattner00736fc2010-04-13 06:37:00 +0000431x86 sibcall / tailcall optimization in CCC mode.
Chris Lattner8b5d9c82010-04-16 06:20:22 +0000432New LSR with "full strength reduction" mode. Description?
433Codegen level OptimizeExtsPass pass, takes advantage of x86 subregs.
Chris Lattner00736fc2010-04-13 06:37:00 +0000434Better code size analysis in loop unswitch, inliner code split out to a new
435 CodeMetrics class for reuse.
Chris Lattnerb22060d2010-03-29 18:39:28 +0000436The ARM backend now has good support for ARMv4 backend (tested on StrongARM
437 hardware), previously only supported ARMv4T and newer.
Chris Lattner00736fc2010-04-13 06:37:00 +0000438Half-float support in APFloat
439Indirect branch + address of label (blog post), particularly useful for interpreters.
Chris Lattner8b5d9c82010-04-16 06:20:22 +0000440Many changes to the pass ordering for improved optimization effectiveness.
441BasicAA improved to be less dependent on "type safe" pointers, it can now look
442 through bitcasts more aggressively.
443GVN PHI Translation improvements. blog post: http://blog.llvm.org/2009/12/advanced-topics-in-redundant-load.html
444llvm.objectsize.
445MachineSSAUpdater.h
446PostRA scheduler for X86?
447llvm.dbg.value, not being used by default though, more in 2.8. Many improvements to debug info
448Support for the GCC option -fno-schedule-insns
449non-temporal load/store
450libllvm2.7.so?? configure with --enable-shared
451dbgs() and -debug-buffer-size=N
452New MicroBlaze backend. http://en.wikipedia.org/wiki/MicroBlaze
453XMM subreg modeling for extraction of the low element.
454
Chris Lattnerb22060d2010-03-29 18:39:28 +0000455
Chris Lattner00736fc2010-04-13 06:37:00 +0000456Opt now works conservatively if no target data is set (is this fully working?)
457Target data now has notion of 'native' integer data types which optimizations can use.
458ARM backend generates instructions in unified assembly syntax.
459New Analysis/InstructionSimplify.h interface for simplifying instructions that don't exist.
460Jump threading is now much more aggressive at simplifying correlated
461 conditionals and threading blocks with otherwise complex logic. CondProp pass
462 removed (functionality merged into jump threading).
463X86 and XCore supports returning arbitrary return values, returning too many values is
464 supported by returning through a hidden pointer.
465verbose-asm now produces information about spill slots and loop nests
Chris Lattnerf04bdc52010-03-17 18:15:52 +0000466
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000467
Chris Lattner8b5d9c82010-04-16 06:20:22 +0000468Defaults to RTTI off (smaller code size!), packagers should build with make REQUIRE_RTTI=1.
469AndersAA got removed
470PredSimplify, LoopVR, GVNPRE, RSProfiling (random sampling profiling) got removed.
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000471LLVM command line tools now overwrite their output, before they would only do this with -f.
472DOUT removed, use DEBUG(errs() instead.
473Much stuff converted to use raw_ostream instead of std::ostream.
474TargetAsmInfo renamed to MCAsmInfo
475llvm/ADT/iterator.h gone.
476
Chris Lattnerdc910082010-03-17 06:41:58 +0000477
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000478</div>
479
Chris Lattner84977642007-09-21 03:54:09 +0000480<!--=========================================================================-->
481<div class="doc_subsection">
Chris Lattner917cc712009-03-02 02:37:32 +0000482<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000483</div>
484
485<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000486<p>LLVM IR has several new features for better support of new targets and that
487expose new optimization opportunities:</p>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000488
Chris Lattner791f77b2008-06-05 06:25:56 +0000489<ul>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000490<li>...</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000491</ul>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000492
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000493</div>
494
495<!--=========================================================================-->
496<div class="doc_subsection">
Chris Lattneracce85d2008-02-10 07:46:44 +0000497<a name="optimizer">Optimizer Improvements</a>
498</div>
499
500<div class="doc_text">
501
Chris Lattner61358ab2009-10-13 17:48:04 +0000502<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattnerf3013872008-10-13 21:50:36 +0000503release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000504
505<ul>
506
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000507<li>...</li>
Chris Lattner917cc712009-03-02 02:37:32 +0000508
Chris Lattner61358ab2009-10-13 17:48:04 +0000509</ul>
Chris Lattner917cc712009-03-02 02:37:32 +0000510
Chris Lattnerf2201912010-03-01 19:29:17 +0000511<p>Also, -anders-aa was removed</p>
512
Chris Lattner61358ab2009-10-13 17:48:04 +0000513</div>
Chris Lattner917cc712009-03-02 02:37:32 +0000514
Chris Lattner917cc712009-03-02 02:37:32 +0000515
Chris Lattner61358ab2009-10-13 17:48:04 +0000516<!--=========================================================================-->
517<div class="doc_subsection">
518<a name="executionengine">Interpreter and JIT Improvements</a>
519</div>
Chris Lattnerf3013872008-10-13 21:50:36 +0000520
Chris Lattner61358ab2009-10-13 17:48:04 +0000521<div class="doc_text">
522
523<ul>
Jeffrey Yasskin01eba392010-01-29 19:10:38 +0000524<li>The JIT now <a
525href="http://llvm.org/viewvc/llvm-project?view=rev&revision=85295">defaults
526to compiling eagerly</a> to avoid a race condition in the lazy JIT.
527Clients that still want the lazy JIT can switch it on by calling
528<tt>ExecutionEngine::DisableLazyCompilation(false)</tt>.</li>
Jeffrey Yasskin40966a72010-02-11 01:07:39 +0000529<li>It is now possible to create more than one JIT instance in the same process.
530These JITs can generate machine code in parallel,
531although <a href="http://llvm.org/docs/ProgrammersManual.html#jitthreading">you
532still have to obey the other threading restrictions</a>.</li>
Chris Lattner0b832202008-06-08 02:45:07 +0000533</ul>
534
535</div>
536
537<!--=========================================================================-->
538<div class="doc_subsection">
Chris Lattner511433e2009-03-02 03:24:11 +0000539<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner0b832202008-06-08 02:45:07 +0000540</div>
541
542<div class="doc_text">
543
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000544<p>We have put a significant amount of work into the code generator
545infrastructure, which allows us to implement more aggressive algorithms and make
546it run faster:</p>
Chris Lattner0b832202008-06-08 02:45:07 +0000547
548<ul>
Chris Lattner511433e2009-03-02 03:24:11 +0000549
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000550<li>...</li>
Chris Lattner84977642007-09-21 03:54:09 +0000551</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000552</div>
553
Chris Lattner917cc712009-03-02 02:37:32 +0000554<!--=========================================================================-->
555<div class="doc_subsection">
556<a name="x86">X86-32 and X86-64 Target Improvements</a>
557</div>
558
559<div class="doc_text">
560<p>New features of the X86 target include:
561</p>
562
563<ul>
Chris Lattner511433e2009-03-02 03:24:11 +0000564
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000565<li>...</li>
Chris Lattner511433e2009-03-02 03:24:11 +0000566
Chris Lattner917cc712009-03-02 02:37:32 +0000567</ul>
568
Chris Lattner917cc712009-03-02 02:37:32 +0000569</div>
Chris Lattner84977642007-09-21 03:54:09 +0000570
571<!--=========================================================================-->
572<div class="doc_subsection">
Chris Lattner11398992009-02-26 07:32:11 +0000573<a name="pic16">PIC16 Target Improvements</a>
574</div>
575
576<div class="doc_text">
577<p>New features of the PIC16 target include:
578</p>
579
580<ul>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000581<li>...</li>
Chris Lattner11398992009-02-26 07:32:11 +0000582</ul>
583
584<p>Things not yet supported:</p>
585
586<ul>
Chris Lattner11398992009-02-26 07:32:11 +0000587<li>Variable arguments.</li>
Chris Lattner511433e2009-03-02 03:24:11 +0000588<li>Interrupts/programs.</li>
Chris Lattner11398992009-02-26 07:32:11 +0000589</ul>
590
591</div>
592
Chris Lattner11398992009-02-26 07:32:11 +0000593<!--=========================================================================-->
594<div class="doc_subsection">
Chris Lattner61358ab2009-10-13 17:48:04 +0000595<a name="ARM">ARM Target Improvements</a>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000596</div>
597
598<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000599<p>New features of the ARM target include:
600</p>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000601
602<ul>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000603
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000604<li>...</li>
Chris Lattner61358ab2009-10-13 17:48:04 +0000605</ul>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000606
Chris Lattnerc441fb82009-03-01 02:30:21 +0000607
Chris Lattner61358ab2009-10-13 17:48:04 +0000608</div>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000609
Chris Lattner61358ab2009-10-13 17:48:04 +0000610<!--=========================================================================-->
611<div class="doc_subsection">
612<a name="OtherTarget">Other Target Specific Improvements</a>
613</div>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000614
Chris Lattner61358ab2009-10-13 17:48:04 +0000615<div class="doc_text">
616<p>New features of other targets include:
617</p>
618
619<ul>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000620<li>...</li>
Chris Lattner61358ab2009-10-13 17:48:04 +0000621</ul>
622
623</div>
624
625<!--=========================================================================-->
626<div class="doc_subsection">
627<a name="newapis">New Useful APIs</a>
628</div>
629
630<div class="doc_text">
631
632<p>This release includes a number of new APIs that are used internally, which
633 may also be useful for external clients.
634</p>
635
636<ul>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000637<li>...</li>
Chris Lattner61358ab2009-10-13 17:48:04 +0000638</ul>
639
640
641</div>
642
643<!--=========================================================================-->
644<div class="doc_subsection">
645<a name="otherimprovements">Other Improvements and New Features</a>
646</div>
647
648<div class="doc_text">
649<p>Other miscellaneous features include:</p>
650
651<ul>
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000652<li>...</li>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000653</ul>
654
655</div>
656
Chris Lattner77d29b12008-06-05 08:02:49 +0000657
658<!--=========================================================================-->
659<div class="doc_subsection">
Chris Lattnerf6662f92008-10-13 17:57:36 +0000660<a name="changes">Major Changes and Removed Features</a>
661</div>
662
663<div class="doc_text">
664
Chris Lattnereeb4da02008-10-13 22:06:31 +0000665<p>If you're already an LLVM user or developer with out-of-tree changes based
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000666on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading
Chris Lattnereeb4da02008-10-13 22:06:31 +0000667from the previous release.</p>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000668
669<ul>
Jeffrey Yasskinbc83d062010-02-09 23:03:44 +0000670<li>The LLVM interpreter now defaults to <em>not</em> using <tt>libffi</tt> even
671if you have it installed. This makes it more likely that an LLVM built on one
672system will work when copied to a similar system. To use <tt>libffi</tt>,
673configure with <tt>--enable-libffi</tt>.
674</li>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000675</ul>
676
677
678<p>In addition, many APIs have changed in this release. Some of the major LLVM
679API changes are:</p>
680
681<ul>
Jeffrey Yasskin4fcd6072010-01-28 01:41:20 +0000682<li><tt>ModuleProvider</tt> has been <a
683href="http://llvm.org/viewvc/llvm-project?view=rev&revision=94686">removed</a>
684and its methods moved to <tt>Module</tt> and <tt>GlobalValue</tt>.
685Most clients can remove uses of <tt>ExistingModuleProvider</tt>,
686replace <tt>getBitcodeModuleProvider</tt> with
687<tt>getLazyBitcodeModule</tt>, and pass their <tt>Module</tt> to
688functions that used to accept <tt>ModuleProvider</tt>. Clients who
689wrote their own <tt>ModuleProvider</tt>s will need to derive from
690<tt>GVMaterializer</tt> instead and use
691<tt>Module::setMaterializer</tt> to attach it to a
692<tt>Module</tt>.</li>
693
694<li><tt>GhostLinkage</tt> has given up the ghost.
695<tt>GlobalValue</tt>s that have not yet been read from their backing
696storage have the same linkage they will have after being read in.
697Clients must replace calls to
698<tt>GlobalValue::hasNotBeenReadFromBitcode</tt> with
699<tt>GlobalValue::isMaterializable</tt>.</li>
Daniel Dunbar4acdede2010-02-10 04:09:52 +0000700
701<li>FIXME: Debug info has been totally redone. Add pointers to new APIs. Substantial caveats about compatibility of .ll and .bc files.</li>
702
Daniel Dunbarca1c8162010-02-14 01:47:19 +0000703<li>The <tt>llvm/Support/DataTypes.h</tt> header has moved
704to <tt>llvm/System/DataTypes.h</tt>.</li>
705
Duncan Sands411432d2010-02-17 17:20:17 +0000706<li>The <tt>isInteger</tt>, <tt>isIntOrIntVector</tt>, <tt>isFloatingPoint</tt>,
707<tt>isFPOrFPVector</tt> and <tt>isFPOrFPVector</tt> methods have been renamed
708<tt>isIntegerTy</tt>, <tt>isIntOrIntVectorTy</tt>, <tt>isFloatingPointTy</tt>,
709<tt>isFPOrFPVectorTy</tt> and <tt>isFPOrFPVectorTy</tt> respectively.</li>
Devang Patelb34dd132008-10-14 20:03:43 +0000710</ul>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000711
Chris Lattnerf6662f92008-10-13 17:57:36 +0000712</div>
713
714
715
Chris Lattner19092612003-10-02 16:38:05 +0000716<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000717<div class="doc_section">
718 <a name="portability">Portability and Supported Platforms</a>
719</div>
Chris Lattner19092612003-10-02 16:38:05 +0000720<!-- *********************************************************************** -->
721
Misha Brukman500bc302003-11-22 00:38:41 +0000722<div class="doc_text">
723
John Criswell0b5b5e92004-12-08 20:35:47 +0000724<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000725
726<ul>
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000727<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattner61358ab2009-10-13 17:48:04 +0000728 Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like
729 systems).</li>
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000730<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit
Chris Lattner61358ab2009-10-13 17:48:04 +0000731 and 64-bit modes.</li>
Chris Lattner252b83d2008-02-06 18:00:06 +0000732<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000733<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
734 support is available for native builds with Visual C++).</li>
Chris Lattner7e23d6e2009-10-16 16:30:58 +0000735<li>Sun x86 and AMD64 machines running Solaris 10, OpenSolaris 0906.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000736<li>Alpha-based machines running Debian GNU/Linux.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000737</ul>
738
Chris Lattnerbc5786b2008-06-05 06:57:39 +0000739<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000740to the machine and operating system on which it is built. However, minor
741porting may be required to get LLVM to work on new platforms. We welcome your
742portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000743
Misha Brukman500bc302003-11-22 00:38:41 +0000744</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000745
746<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000747<div class="doc_section">
748 <a name="knownproblems">Known Problems</a>
749</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000750<!-- *********************************************************************** -->
751
Misha Brukman500bc302003-11-22 00:38:41 +0000752<div class="doc_text">
753
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000754<p>This section contains significant known problems with the LLVM system,
Chris Lattnere18b32e2008-11-10 05:40:34 +0000755listed by component. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000756href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000757there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000758
Chris Lattner477a1fd2010-03-17 17:25:49 +0000759<ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000760<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
761using the stock GCC 3.x.x series 'out the box',
Chris Lattner554ee4a2009-11-03 21:50:09 +0000762See: <a href="GettingStarted.html#brokengcc">Broken versions of GCC and other tools</a>.
Chris Lattner61358ab2009-10-13 17:48:04 +0000763However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
764for x86/x86-64 has been made available from the third party AuroraUX Project
765that has been meticulously tested for bootstrapping LLVM &amp; Clang.</li>
766</ul>
767
Misha Brukman500bc302003-11-22 00:38:41 +0000768</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000769
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000770<!-- ======================================================================= -->
771<div class="doc_subsection">
772 <a name="experimental">Experimental features included with this release</a>
773</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000774
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000775<div class="doc_text">
776
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000777<p>The following components of this LLVM release are either untested, known to
778be broken or unreliable, or are in early development. These components should
779not be relied on, and bugs should not be filed against them, but they may be
780useful to some people. In particular, if you would like to work on one of these
Chris Lattner2b659ef2008-02-12 06:29:45 +0000781components, please contact us on the <a
782href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000783
784<ul>
Wesley Peck7c4a1212010-03-18 14:31:30 +0000785<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
786 backends are experimental.</li>
Bill Wendling99dac472009-03-02 07:54:14 +0000787<li>The <tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000788 supported value for this option. The MachO writer is experimental, and
789 works much better in mainline SVN.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000790</ul>
791
792</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000793
Misha Brukman500bc302003-11-22 00:38:41 +0000794<!-- ======================================================================= -->
795<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000796 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000797</div>
798
799<div class="doc_text">
800
801<ul>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000802 <li>The X86 backend does not yet support
803 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
804 floating point stack</a>. It supports the 'f' and 't' constraints, but not
805 'u'.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000806 <li>The X86 backend generates inefficient floating point code when configured
807 to generate code for systems that don't have SSE2.</li>
Duncan Sands47eff2b2008-06-08 19:38:43 +0000808 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswell524a5dd2009-03-02 15:28:15 +0000809 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
810 runtime currently due
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000811 to <a href="http://llvm.org/PR2255">several</a>
John Criswell524a5dd2009-03-02 15:28:15 +0000812 <a href="http://llvm.org/PR2257">bugs</a> and due to lack of support for
813 the
814 'u' inline assembly constraint and for X87 floating point inline assembly.</li>
Dan Gohman8207ba92008-06-08 23:05:11 +0000815 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner917cc712009-03-02 02:37:32 +0000816 <tt>va_arg</tt>. Currently, the llvm-gcc and front-ends support variadic
Dan Gohman8207ba92008-06-08 23:05:11 +0000817 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000818</ul>
819
820</div>
821
822<!-- ======================================================================= -->
823<div class="doc_subsection">
824 <a name="ppc-be">Known problems with the PowerPC back-end</a>
825</div>
826
827<div class="doc_text">
828
829<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000830<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000831compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000832</ul>
833
834</div>
835
836<!-- ======================================================================= -->
837<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000838 <a name="arm-be">Known problems with the ARM back-end</a>
839</div>
840
841<div class="doc_text">
842
843<ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000844<li>Support for the Advanced SIMD (Neon) instruction set is still incomplete
845and not well tested. Some features may not work at all, and the code quality
846may be poor in some cases.</li>
Chris Lattner57a460e2007-05-23 04:39:32 +0000847<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000848processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000849results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswell524a5dd2009-03-02 15:28:15 +0000850<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000851</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000852</ul>
853
854</div>
855
856<!-- ======================================================================= -->
857<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000858 <a name="sparc-be">Known problems with the SPARC back-end</a>
859</div>
860
861<div class="doc_text">
862
863<ul>
John Criswell524a5dd2009-03-02 15:28:15 +0000864<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Chris Lattner26299222006-11-18 07:51:14 +0000865 support the 64-bit SPARC ABI (-m64).</li>
866</ul>
867
868</div>
869
870<!-- ======================================================================= -->
871<div class="doc_subsection">
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000872 <a name="mips-be">Known problems with the MIPS back-end</a>
873</div>
874
875<div class="doc_text">
876
877<ul>
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000878<li>64-bit MIPS targets are not supported yet.</li>
879</ul>
880
881</div>
882
883<!-- ======================================================================= -->
884<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000885 <a name="alpha-be">Known problems with the Alpha back-end</a>
886</div>
887
888<div class="doc_text">
889
890<ul>
891
892<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
893appropriate nops inserted to ensure restartability.</li>
894
John Criswellc0c186d2005-11-08 21:11:33 +0000895</ul>
896</div>
897
Chris Lattner26299222006-11-18 07:51:14 +0000898<!-- ======================================================================= -->
899<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000900 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000901</div>
902
903<div class="doc_text">
904
905<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000906<li><a href="http://llvm.org/PR802">The C backend has only basic support for
907 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000908<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
909 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif4906abe2009-03-02 12:02:51 +0000910 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000911<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands50723a92009-02-25 11:51:54 +0000912<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000913</ul>
914
915</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000916
Misha Brukman500bc302003-11-22 00:38:41 +0000917
918<!-- ======================================================================= -->
919<div class="doc_subsection">
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000920 <a name="c-fe">Known problems with the llvm-gcc C and C++ front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000921</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000922
Misha Brukman500bc302003-11-22 00:38:41 +0000923<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000924
Chris Lattner5733b272008-06-05 06:35:40 +0000925<p>The only major language feature of GCC not supported by llvm-gcc is
926 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
927 are only supported on some targets. For example, trampolines are only
Duncan Sands27aff872008-06-08 20:18:35 +0000928 supported on some targets (these are used when you take the address of a
929 nested function).</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000930
Chris Lattner5733b272008-06-05 06:35:40 +0000931<p>If you run into GCC extensions which are not supported, please let us know.
932</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000933
Misha Brukman500bc302003-11-22 00:38:41 +0000934</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000935
Misha Brukman500bc302003-11-22 00:38:41 +0000936<!-- ======================================================================= -->
937<div class="doc_subsection">
Chris Lattner1eb4df62008-10-30 03:58:13 +0000938 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
939</div>
940
941<div class="doc_text">
Gabor Greifba10fe02008-11-04 21:50:59 +0000942<ul>
Chris Lattner1eb4df62008-10-30 03:58:13 +0000943<li>Fortran support generally works, but there are still several unresolved bugs
Chris Lattner61358ab2009-10-13 17:48:04 +0000944 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
945 tools/gfortran component for details.</li>
Gabor Greifba10fe02008-11-04 21:50:59 +0000946</ul>
Chris Lattner1eb4df62008-10-30 03:58:13 +0000947</div>
Misha Brukman500bc302003-11-22 00:38:41 +0000948
Chris Lattner2b659ef2008-02-12 06:29:45 +0000949<!-- ======================================================================= -->
950<div class="doc_subsection">
Chris Lattner5733b272008-06-05 06:35:40 +0000951 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000952</div>
953
954<div class="doc_text">
John Criswell524a5dd2009-03-02 15:28:15 +0000955The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
956technology, and problems should be expected.
Chris Lattner2b659ef2008-02-12 06:29:45 +0000957<ul>
Duncan Sands27aff872008-06-08 20:18:35 +0000958<li>The Ada front-end currently only builds on X86-32. This is mainly due
John Criswell524a5dd2009-03-02 15:28:15 +0000959to lack of trampoline support (pointers to nested functions) on other platforms.
960However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000961which does support trampolines.</li>
962<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
Duncan Sands326a4982009-02-25 11:59:06 +0000963This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
964exception handling, which is used internally by the compiler.
Chris Lattner61358ab2009-10-13 17:48:04 +0000965Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
Duncan Sands978bcee2008-10-13 17:27:23 +0000966<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
967and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sands326a4982009-02-25 11:59:06 +0000968(c380004 also fails with gcc-4.2 mainline).
969If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
970causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sandsdd3e6722009-03-02 16:35:57 +0000971<li>Some GCC specific Ada tests continue to crash the compiler.</li>
Chris Lattner61358ab2009-10-13 17:48:04 +0000972<li>The <tt>-E</tt> binder option (exception backtraces)
Chris Lattner2b659ef2008-02-12 06:29:45 +0000973<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
Chris Lattner61358ab2009-10-13 17:48:04 +0000974crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000975<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
976or finish at a non-byte offset</a> in a record. Workaround: do not pack records
977or use representation clauses that result in a field of a non-discrete type
978starting or finishing in the middle of a byte.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000979<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
980'main' as generated by the Ada binder to be invalid</a>.
981Workaround: hand edit the file to use pointers for <tt>argv</tt> and
982<tt>envp</tt> rather than integers.</li>
983<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
984ignored</a>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000985</ul>
986</div>
987
Chris Lattner79c3fe12003-10-02 04:57:28 +0000988<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000989<div class="doc_section">
990 <a name="additionalinfo">Additional Information</a>
991</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000992<!-- *********************************************************************** -->
993
Misha Brukman500bc302003-11-22 00:38:41 +0000994<div class="doc_text">
995
Chris Lattner416db102005-05-16 17:13:10 +0000996<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000997href="http://llvm.org">LLVM web page</a>, in particular in the <a
998href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000999contains versions of the API documentation which is up-to-date with the
1000Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +00001001You can access versions of these documents specific to this release by going
1002into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +00001003
Misha Brukman500bc302003-11-22 00:38:41 +00001004<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerc463b272005-10-29 07:07:09 +00001005us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +00001006lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +00001007
Misha Brukman500bc302003-11-22 00:38:41 +00001008</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +00001009
1010<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +00001011
Misha Brukman500bc302003-11-22 00:38:41 +00001012<hr>
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Chris Lattnerb4b0ce72007-05-18 00:44:29 +00001019 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
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