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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 152c1061e0b4ad379eec5fa38ee0091fc11ff936 / . / docs / ReleaseNotes.html
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4<head>
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Dan Gohmanb44f6c62010-05-03 23:51:05 +0000[diff] [blame]8 <title>LLVM 2.8 Release Notes</title>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]9</head>
10<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]11
Dan Gohmanb44f6c62010-05-03 23:51:05 +0000[diff] [blame]12<div class="doc_title">LLVM 2.8 Release Notes</div>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]13
Chris Lattner0e464a92010-03-17 04:02:39 +0000[diff] [blame]14<img align=right src="http://llvm.org/img/DragonSmall.png"
Gabor Greifee2187a2010-04-22 10:21:43 +0000[diff] [blame]15 width="136" height="136" alt="LLVM Dragon Logo">
Chris Lattner0e464a92010-03-17 04:02:39 +0000[diff] [blame]16
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]17<ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]18 <li><a href="#intro">Introduction</a></li>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]19 <li><a href="#subproj">Sub-project Status Update</a></li>
Dan Gohmanb44f6c62010-05-03 23:51:05 +0000[diff] [blame]20 <li><a href="#externalproj">External Projects Using LLVM 2.8</a></li>
21 <li><a href="#whatsnew">What's New in LLVM 2.8?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +0000[diff] [blame]22 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Dan Gohman44aa9212008-10-14 16:23:02 +0000[diff] [blame]23 <li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]24 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]25</ol>
26
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]27<div class="doc_author">
Dan Gohman44aa9212008-10-14 16:23:02 +0000[diff] [blame]28 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]29</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]30
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]31<!--
Chris Lattner7b91eda2010-04-22 05:41:35 +0000[diff] [blame]32<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.8
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]33release.<br>
34You may prefer the
Dan Gohmanb44f6c62010-05-03 23:51:05 +0000[diff] [blame]35<a href="http://llvm.org/releases/2.7/docs/ReleaseNotes.html">LLVM 2.7
36Release Notes</a>.</h1>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]37-->
Jeffrey Yasskinbec48772010-01-28 01:14:43 +0000[diff] [blame]38
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]39<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]40<div class="doc_section">
41 <a name="intro">Introduction</a>
42</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]43<!-- *********************************************************************** -->
44
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]45<div class="doc_text">
46
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]47<p>This document contains the release notes for the LLVM Compiler
Dan Gohman7ae3ac82010-05-03 23:52:21 +0000[diff] [blame]48Infrastructure, release 2.8. Here we describe the status of LLVM, including
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]49major improvements from the previous release and significant known problems.
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]50All LLVM releases may be downloaded from the <a
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]51href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]52
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]53<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]54release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]55web site</a>. If you have questions or comments, the <a
Chris Lattnerc66bfef2010-03-17 04:41:49 +0000[diff] [blame]56href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's
57Mailing List</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]58
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]59<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]60main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greiffa933f82008-10-14 11:00:32 +0000[diff] [blame]61current one. To see the release notes for a specific release, please see the
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]62<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]63
64</div>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]65
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]66
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]67<!--
68Almost dead code.
69 include/llvm/Analysis/LiveValues.h => Dan
70 lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8.
Chris Lattner61c70e92010-08-28 04:09:24 +0000[diff] [blame]71 GEPSplitterPass
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]72-->
73
74
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]75<!-- Features that need text if they're finished for 2.9:
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]76 combiner-aa?
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]77 strong phi elim
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]78 loop dependence analysis
Chris Lattner885b6612010-08-28 16:33:36 +0000[diff] [blame]79 TBAA
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]80 CorrelatedValuePropagation
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]81 -->
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]82
83 <!-- Announcement, lldb, libc++ -->
Chris Lattnerafa41632010-09-29 07:25:03 +0000[diff] [blame]84
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]85
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]86<!-- *********************************************************************** -->
87<div class="doc_section">
88 <a name="subproj">Sub-project Status Update</a>
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]89</div>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]90<!-- *********************************************************************** -->
Chris Lattnerea34f642008-06-08 21:34:41 +0000[diff] [blame]91
92<div class="doc_text">
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]93<p>
Dan Gohmanb44f6c62010-05-03 23:51:05 +0000[diff] [blame]94The LLVM 2.8 distribution currently consists of code from the core LLVM
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]95repository (which roughly includes the LLVM optimizers, code generators
96and supporting tools), the Clang repository and the llvm-gcc repository. In
97addition to this code, the LLVM Project includes other sub-projects that are in
98development. Here we include updates on these subprojects.
Bill Wendling63d8c552009-03-02 04:28:57 +0000[diff] [blame]99</p>
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]100
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]101</div>
102
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]103
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]104<!--=========================================================================-->
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]105<div class="doc_subsection">
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000[diff] [blame]106<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]107</div>
108
109<div class="doc_text">
110
Chris Lattner095539f2010-04-26 17:42:18 +0000[diff] [blame]111<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
112C++, and Objective-C languages. Clang aims to provide a better user experience
113through expressive diagnostics, a high level of conformance to language
114standards, fast compilation, and low memory use. Like LLVM, Clang provides a
115modular, library-based architecture that makes it suitable for creating or
116integrating with other development tools. Clang is considered a
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]117production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
118(32- and 64-bit), and for darwin-arm targets.</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]119
Chris Lattner922d00f2010-07-21 15:57:40 +0000[diff] [blame]120<p>In the LLVM 2.8 time-frame, the Clang team has made many improvements:</p>
Bill Wendling741748a2008-10-27 09:27:33 +0000[diff] [blame]121
Douglas Gregorf2409d52010-10-04 07:02:35 +0000[diff] [blame]122 <ul>
123 <li>Clang C++ is now feature-complete with respect to the ISO C++ 1998 and 2003 standards.</li>
124 <li>Added support for Objective-C++.</li>
125 <li>Clang now uses LLVM-MC to directly generate object code and to parse inline assembly (on Darwin).</li>
126 <li>Introduced many new warnings, including <code>-Wmissing-field-initializers</code>, <code>-Wshadow</code>, <code>-Wno-protocol</code>, <code>-Wtautological-compare</code>, <code>-Wstrict-selector-match</code>, <code>-Wcast-align</code>, <code>-Wunused</code> improvements, and greatly improved format-string checking.</li>
127 <li>Introduced the "libclang" library, a C interface to Clang intended to support IDE clients.</li>
128 <li>Added support for <code>#pragma GCC visibility</code>, <code>#pragma align</code>, and others.</li>
Bruno Cardoso Lopes48f95432010-10-04 22:07:22 +0000[diff] [blame]129 <li>Added support for SSE, AVX, ARM NEON, and AltiVec.</li>
Daniel Dunbar4a517fc2010-10-04 17:06:49 +0000[diff] [blame]130 <li>Improved support for many Microsoft extensions.</li>
Douglas Gregorf2409d52010-10-04 07:02:35 +0000[diff] [blame]131 <li>Implemented support for blocks in C++.</li>
132 <li>Implemented precompiled headers for C++.</li>
133 <li>Improved abstract syntax trees to retain more accurate source information.</li>
Daniel Dunbar4a517fc2010-10-04 17:06:49 +0000[diff] [blame]134 <li>Added driver support for handling LLVM IR and bitcode files directly.</li>
135 <li>Major improvements to compiler correctness for exception handling.</li>
136 <li>Improved generated code quality in some areas:
137 <ul>
138 <li>Good code generation for X86-32 and X86-64 ABI handling.</li>
139 <li>Improved code generation for bit-fields, although important work remains.</li>
140 </ul>
141 </li>
Douglas Gregorf2409d52010-10-04 07:02:35 +0000[diff] [blame]142 </ul>
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000[diff] [blame]143</div>
144
145<!--=========================================================================-->
146<div class="doc_subsection">
147<a name="clangsa">Clang Static Analyzer</a>
148</div>
149
150<div class="doc_text">
151
Chris Lattner8cdd7932010-04-22 06:38:11 +0000[diff] [blame]152<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a>
153 project is an effort to use static source code analysis techniques to
154 automatically find bugs in C and Objective-C programs (and hopefully <a
155 href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the
156 future</a>!). The tool is very good at finding bugs that occur on specific
157 paths through code, such as on error conditions.</p>
Chris Lattnercc042612008-10-14 00:52:49 +0000[diff] [blame]158
Chris Lattner2e38c7f2010-09-30 00:34:43 +0000[diff] [blame]159<p>The LLVM 2.8 release fixes a number of bugs and slightly improves precision
160 over 2.7, but there are no major new features in the release.
Chris Lattner8cdd7932010-04-22 06:38:11 +0000[diff] [blame]161</p>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]162
163</div>
164
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]165<!--=========================================================================-->
166<div class="doc_subsection">
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]167<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]168</div>
169
170<div class="doc_text">
171<p>
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]172<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000[diff] [blame]173gcc-4.5. Unlike llvm-gcc, dragonegg in theory does not require any gcc-4.5
174modifications whatsoever (currently one small patch is needed) thanks to the
175new <a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>.
176DragonEgg is a gcc plugin that makes gcc-4.5 use the LLVM optimizers and code
177generators instead of gcc's, just like with llvm-gcc.
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]178</p>
179
180<p>
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000[diff] [blame]181DragonEgg is still a work in progress, but it is able to compile a lot of code,
182for example all of gcc, LLVM and clang. Currently Ada, C, C++ and Fortran work
183well, while all other languages either don't work at all or only work poorly.
184For the moment only the x86-32 and x86-64 targets are supported, and only on
185linux and darwin (darwin may need additional gcc patches).
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]186</p>
187
188<p>
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000[diff] [blame]189The 2.8 release has the following notable changes:
190<ul>
191<li>The plugin loads faster due to exporting fewer symbols.</li>
192<li>Additional vector operations such as addps256 are now supported.</li>
193<li>Ada global variables with no initial value are no longer zero initialized,
194resulting in better optimization.</li>
195<li>The '-fplugin-arg-dragonegg-enable-gcc-optzns' flag now runs all gcc
196optimizers, rather than just a handful.</li>
197<li>Fortran programs using common variables now link correctly.</li>
198<li>GNU OMP constructs no longer crash the compiler.</li>
199</ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]200
201</div>
202
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]203<!--=========================================================================-->
204<div class="doc_subsection">
205<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
206</div>
207
208<div class="doc_text">
209<p>
210The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
211a Java Virtual Machine (Java VM or JVM) that uses LLVM for static and
212just-in-time compilation. As of LLVM 2.8, VMKit now supports copying garbage
213collectors, and can be configured to use MMTk's copy mark-sweep garbage
214collector. In LLVM 2.8, the VMKit .NET VM is no longer being maintained.
215</p>
216</div>
217
218<!--=========================================================================-->
219<div class="doc_subsection">
220<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
221</div>
222
223<div class="doc_text">
224<p>
225The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
226is a simple library that provides an implementation of the low-level
227target-specific hooks required by code generation and other runtime components.
228For example, when compiling for a 32-bit target, converting a double to a 64-bit
229unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
230function. The compiler-rt library provides highly optimized implementations of
231this and other low-level routines (some are 3x faster than the equivalent
232libgcc routines).</p>
233
234<p>
235All of the code in the compiler-rt project is available under the standard LLVM
236License, a "BSD-style" license. New in LLVM 2.8, compiler_rt now supports
237soft floating point (for targets that don't have a real floating point unit),
238and includes an extensive testsuite for the "blocks" language feature and the
239blocks runtime included in compiler_rt.</p>
240
241</div>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]242
243<!--=========================================================================-->
244<div class="doc_subsection">
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]245<a name="lldb">LLDB: Low Level Debugger</a>
246</div>
247
248<div class="doc_text">
249<p>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]250<a href="http://lldb.llvm.org/">LLDB</a> is a brand new member of the LLVM
251umbrella of projects. LLDB is a next generation, high-performance debugger. It
252is built as a set of reusable components which highly leverage existing
253libraries in the larger LLVM Project, such as the Clang expression parser, the
254LLVM disassembler and the LLVM JIT.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]255
256<p>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]257LLDB is in early development and not included as part of the LLVM 2.8 release,
258but is mature enough to support basic debugging scenarios on Mac OS X in C,
259Objective-C and C++. We'd really like help extending and expanding LLDB to
260support new platforms, new languages, new architectures, and new features.
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]261</p>
262
263</div>
264
265<!--=========================================================================-->
266<div class="doc_subsection">
267<a name="libc++">libc++: C++ Standard Library</a>
268</div>
269
270<div class="doc_text">
271<p>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]272<a href="http://libc++.llvm.org/">libc++</a> is another new member of the LLVM
273family. It is an implementation of the C++ standard library, written from the
274ground up to specifically target the forthcoming C++'0X standard and focus on
275delivering great performance.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]276
277<p>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]278As of the LLVM 2.8 release, libc++ is virtually feature complete, but would
279benefit from more testing and better integration with Clang++. It is also
280looking forward to the C++ committee finalizing the C++'0x standard.
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]281</p>
282
283</div>
284
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]285
Daniel Dunbar97b01a82010-10-04 17:39:47 +0000[diff] [blame]286
287<!--=========================================================================-->
288<div class="doc_subsection">
289<a name="klee">KLEE: A Symbolic Execution Virtual Machine</a>
290</div>
291
292<div class="doc_text">
293<p>
294<a href="http://klee.llvm.org/">KLEE</a> is a symbolic execution framework for
295programs in LLVM bitcode form. KLEE tries to symbolically evaluate "all" paths
296through the application and records state transitions that lead to fault
297states. This allows it to construct testcases that lead to faults and can even
298be used to verify some algorithms.
299</p>
300
301<p>Although KLEE does not have any major new features as of 2.8, we have made
302various minor improvements, particular to ease development:</p>
303<ul>
304 <li>Added support for LLVM 2.8. KLEE currently maintains compatibility with
305 LLVM 2.6, 2.7, and 2.8.</li>
306 <li>Added a buildbot for 2.6, 2.7, and trunk. A 2.8 buildbot will be coming
307 soon following release.</li>
308 <li>Fixed many C++ code issues to allow building with Clang++. Mostly
309 complete, except for the version of MiniSAT which is inside the KLEE STP
310 version.</li>
311 <li>Improved support for building with separate source and build
312 directories.</li>
313 <li>Added support for "long double" on x86.</li>
314 <li>Initial work on KLEE support for using 'lit' test runner instead of
315 DejaGNU.</li>
316 <li>Added <tt>configure</tt> support for using an external version of
317 STP.</li>
318</ul>
319
320</div>
321
322
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]323<!-- *********************************************************************** -->
324<div class="doc_section">
Chris Lattner922d00f2010-07-21 15:57:40 +0000[diff] [blame]325 <a name="externalproj">External Open Source Projects Using LLVM 2.8</a>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]326</div>
327<!-- *********************************************************************** -->
328
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]329<div class="doc_text">
330
331<p>An exciting aspect of LLVM is that it is used as an enabling technology for
332 a lot of other language and tools projects. This section lists some of the
Chris Lattner922d00f2010-07-21 15:57:40 +0000[diff] [blame]333 projects that have already been updated to work with LLVM 2.8.</p>
Chris Lattner7c8e7962010-04-26 17:38:10 +0000[diff] [blame]334</div>
335
Chris Lattner2e38c7f2010-09-30 00:34:43 +0000[diff] [blame]336<!--=========================================================================-->
337<div class="doc_subsection">
338<a name="tce">TTA-based Codesign Environment (TCE)</a>
339</div>
340
341<div class="doc_text">
342<p>
343<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing
344application-specific processors (ASP) based on the Transport triggered
345architecture (TTA). The toolset provides a complete co-design flow from C/C++
346programs down to synthesizable VHDL and parallel program binaries. Processor
347customization points include the register files, function units, supported
348operations, and the interconnection network.</p>
349
350<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target
351independent optimizations and also for parts of code generation. It generates
352new LLVM-based code generators "on the fly" for the designed TTA processors and
353loads them in to the compiler backend as runtime libraries to avoid per-target
354recompilation of larger parts of the compiler chain.</p>
355
356</div>
357
358<!--=========================================================================-->
359<div class="doc_subsection">
360<a name="Horizon">Horizon Bytecode Compiler</a>
361</div>
362
363<div class="doc_text">
364<p>
365<a href="http://www.quokforge.org/projects/horizon">Horizon</a> is a bytecode
366language and compiler written on top of LLVM, intended for producing
367single-address-space managed code operating systems that
368run faster than the equivalent multiple-address-space C systems.
Gabor Greif9f459132010-10-04 17:03:49 +0000[diff] [blame]369More in-depth blurb is available on the <a
370href="http://www.quokforge.org/projects/horizon/wiki/Wiki">wiki</a>.</p>
Chris Lattner2e38c7f2010-09-30 00:34:43 +0000[diff] [blame]371
372</div>
373
374<!--=========================================================================-->
375<div class="doc_subsection">
376<a name="clamav">Clam AntiVirus</a>
377</div>
378
379<div class="doc_text">
380<p>
Gabor Greif265bc892010-10-04 17:54:30 +0000[diff] [blame]381<a href="http://www.clamav.net">Clam AntiVirus</a> is an open source (GPL)
Chris Lattner2e38c7f2010-09-30 00:34:43 +0000[diff] [blame]382anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail
383gateways. Since version 0.96 it has <a
384href="http://vrt-sourcefire.blogspot.com/2010/09/introduction-to-clamavs-low-level.html">bytecode
385signatures</a> that allow writing detections for complex malware. It
386uses LLVM's JIT to speed up the execution of bytecode on
Gabor Greif9f459132010-10-04 17:03:49 +0000[diff] [blame]387X86, X86-64, PPC32/64, falling back to its own interpreter otherwise.
388The git version was updated to work with LLVM 2.8.
Chris Lattner2e38c7f2010-09-30 00:34:43 +0000[diff] [blame]389</p>
390
391<p>The <a
392href="http://git.clamav.net/gitweb?p=clamav-bytecode-compiler.git;a=blob_plain;f=docs/user/clambc-user.pdf">
393ClamAV bytecode compiler</a> uses Clang and LLVM to compile a C-like
394language, insert runtime checks, and generate ClamAV bytecode.</p>
395
396</div>
397
398<!--=========================================================================-->
399<div class="doc_subsection">
400<a name="pure">Pure</a>
401</div>
402
403<div class="doc_text">
404<p>
405<a href="http://pure-lang.googlecode.com/">Pure</a>
406is an algebraic/functional
407programming language based on term rewriting. Programs are collections
408of equations which are used to evaluate expressions in a symbolic
409fashion. Pure offers dynamic typing, eager and lazy evaluation, lexical
410closures, a hygienic macro system (also based on term rewriting),
411built-in list and matrix support (including list and matrix
412comprehensions) and an easy-to-use C interface. The interpreter uses
413LLVM as a backend to JIT-compile Pure programs to fast native code.</p>
414
415<p>Pure versions 0.44 and later have been tested and are known to work with
416LLVM 2.8 (and continue to work with older LLVM releases >= 2.5).</p>
417
418</div>
419
420<!--=========================================================================-->
421<div class="doc_subsection">
422<a name="GHC">Glasgow Haskell Compiler (GHC)</a>
423</div>
424
425<div class="doc_text">
426<p>
427<a href="http://www.haskell.org/ghc/">GHC</a> is an open source,
428state-of-the-art programming suite for
429Haskell, a standard lazy functional programming language. It includes
430an optimizing static compiler generating good code for a variety of
431platforms, together with an interactive system for convenient, quick
432development.</p>
433
434<p>In addition to the existing C and native code generators, GHC 7.0 now
435supports an <a
436href="http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/Backends/LLVM">LLVM
437code generator</a>. GHC supports LLVM 2.7 and later.</p>
438
439</div>
440
441<!--=========================================================================-->
442<div class="doc_subsection">
443<a name="Clay">Clay Programming Language</a>
444</div>
445
446<div class="doc_text">
447<p>
Chris Lattner97fe6452010-09-30 01:12:09 +0000[diff] [blame]448<a href="http://tachyon.in/clay/">Clay</a> is a new systems programming
Chris Lattner2e38c7f2010-09-30 00:34:43 +0000[diff] [blame]449language that is specifically designed for generic programming. It makes
450generic programming very concise thanks to whole program type propagation. It
451uses LLVM as its backend.</p>
452
453</div>
Chris Lattner3a1d4cf2010-04-22 21:34:16 +0000[diff] [blame]454
Chris Lattnere0518442010-10-01 06:34:49 +0000[diff] [blame]455<!--=========================================================================-->
456<div class="doc_subsection">
457<a name="llvm-py">llvm-py Python Bindings for LLVM</a>
458</div>
459
460<div class="doc_text">
461<p>
462<a href="http://www.mdevan.org/llvm-py/">llvm-py</a> has been updated to work
463with LLVM 2.8. llvm-py provides Python bindings for LLVM, allowing you to write a
464compiler backend or a VM in Python.</p>
465
466</div>
467
468
Chris Lattner2fb6e5c2010-10-03 23:09:03 +0000[diff] [blame]469<!--=========================================================================-->
470<div class="doc_subsection">
471<a name="FAUST">FAUST Real-Time Audio Signal Processing Language</a>
472</div>
473
474<div class="doc_text">
475<p>
476<a href="http://faust.grame.fr">FAUST</a> is a compiled language for real-time
477audio signal processing. The name FAUST stands for Functional AUdio STream. Its
478programming model combines two approaches: functional programming and block
479diagram composition. In addition with the C, C++, JAVA output formats, the
480Faust compiler can now generate LLVM bitcode, and works with LLVM 2.7 and
4812.8.</p>
482
483</div>
484
485<!--=========================================================================-->
486<div class="doc_subsection">
487<a name="jade">Jade Just-in-time Adaptive Decoder Engine</a>
488</div>
489
490<div class="doc_text">
491<p><a
492href="http://sourceforge.net/apps/trac/orcc/wiki/JadeDocumentation">Jade</a>
493(Just-in-time Adaptive Decoder Engine) is a generic video decoder engine using
494LLVM for just-in-time compilation of video decoder configurations. Those
495configurations are designed by MPEG Reconfigurable Video Coding (RVC) committee.
496MPEG RVC standard is built on a stream-based dataflow representation of
497decoders. It is composed of a standard library of coding tools written in
Duncan Sands30be9e42010-10-04 10:04:14 +0000[diff] [blame]498RVC-CAL language and a dataflow configuration &#8212; block diagram &#8212;
Chris Lattner2fb6e5c2010-10-03 23:09:03 +0000[diff] [blame]499of a decoder.</p>
500
501<p>Jade project is hosted as part of the <a href="http://orcc.sf.net">Open
502RVC-CAL Compiler</a> and requires it to translate the RVC-CAL standard library
503of video coding tools into an LLVM assembly code.</p>
504
505</div>
506
507<!--=========================================================================-->
508<div class="doc_subsection">
509<a name="neko_llvm_jit">LLVM JIT for Neko VM</a>
510</div>
511
512<div class="doc_text">
513<p><a href="http://github.com/vava/neko_llvm_jit">Neko LLVM JIT</a>
514replaces the standard Neko JIT with an LLVM-based implementation. While not
515fully complete, it is already providing a 1.5x speedup on 64-bit systems.
516Neko LLVM JIT requires LLVM 2.8 or later.</p>
517
518</div>
519
520<!--=========================================================================-->
521<div class="doc_subsection">
522<a name="crack">Crack Scripting Language</a>
523</div>
524
525<div class="doc_text">
526<p>
527<a href="http://code.google.com/p/crack-language/">Crack</a> aims to provide
528the ease of development of a scripting language with the performance of a
529compiled language. The language derives concepts from C++, Java and Python,
530incorporating object-oriented programming, operator overloading and strong
531typing. Crack 0.2 works with LLVM 2.7, and the forthcoming Crack 0.2.1 release
532builds on LLVM 2.8.</p>
533
534</div>
535
536<!--=========================================================================-->
537<div class="doc_subsection">
538<a name="DresdenTM">Dresden TM Compiler (DTMC)</a>
539</div>
540
541<div class="doc_text">
542<p>
543<a href="http://tm.inf.tu-dresden.de">DTMC</a> provides support for
544Transactional Memory, which is an easy-to-use and efficient way to synchronize
545accesses to shared memory. Transactions can contain normal C/C++ code (e.g.,
Gabor Greif9f459132010-10-04 17:03:49 +0000[diff] [blame]546<code>__transaction { list.remove(x); x.refCount--; }</code>) and will be executed
Chris Lattner2fb6e5c2010-10-03 23:09:03 +0000[diff] [blame]547virtually atomically and isolated from other transactions.</p>
548
549</div>
550
551<!--=========================================================================-->
552<div class="doc_subsection">
Chris Lattnerc5fd1562010-10-04 16:06:37 +0000[diff] [blame]553<a name="Kai">Kai Programming Language</a>
Chris Lattner2fb6e5c2010-10-03 23:09:03 +0000[diff] [blame]554</div>
555
556<div class="doc_text">
557<p>
558<a href="http://www.oriontransfer.co.nz/research/kai">Kai</a> (Japanese 会 for
559meeting/gathering) is an experimental interpreter that provides a highly
560extensible runtime environment and explicit control over the compilation
561process. Programs are defined using nested symbolic expressions, which are all
562parsed into first-class values with minimal intrinsic semantics. Kai can
563generate optimised code at run-time (using LLVM) in order to exploit the nature
564of the underlying hardware and to integrate with external software libraries.
565It is a unique exploration into world of dynamic code compilation, and the
566interaction between high level and low level semantics.</p>
567
568</div>
569
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]570<!--=========================================================================-->
571<div class="doc_subsection">
572<a name="OSL">OSL: Open Shading Language</a>
573</div>
574
575<div class="doc_text">
576<p>
577<a href="http://code.google.com/p/openshadinglanguage/">OSL</a> is a shading
578language designed for use in physically based renderers and in particular
579production rendering. By using LLVM instead of the interpreter, it was able to
580meet its performance goals (&gt;= C-code) while retaining the benefits of
581runtime specialization and a portable high-level language.
582</p>
583
584</div>
585
586
Chris Lattnere0518442010-10-01 06:34:49 +0000[diff] [blame]587
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]588<!-- *********************************************************************** -->
589<div class="doc_section">
Chris Lattner922d00f2010-07-21 15:57:40 +0000[diff] [blame]590 <a name="whatsnew">What's New in LLVM 2.8?</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]591</div>
592<!-- *********************************************************************** -->
593
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]594<div class="doc_text">
595
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]596<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]597minor improvements. Some of the major improvements and new features are listed
598in this section.
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]599</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]600
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]601</div>
602
603<!--=========================================================================-->
604<div class="doc_subsection">
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]605<a name="majorfeatures">Major New Features</a>
606</div>
607
608<div class="doc_text">
609
Chris Lattner922d00f2010-07-21 15:57:40 +0000[diff] [blame]610<p>LLVM 2.8 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]611
612<ul>
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]613<li>As mentioned above, <a href="#libc++">libc++</a> and <a
614 href="#lldb">LLDB</a> are major new additions to the LLVM collective.</li>
615<li>LLVM 2.8 now has pretty decent support for debugging optimized code. You
616 should be able to reliably get debug info for function arguments, assuming
617 that the value is actually available where you have stopped.</li>
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]618<li>A new 'llvm-diff' tool is available that does a semantic diff of .ll
619 files.</li>
620<li>The <a href="#mc">MC subproject</a> has made major progress in this release.
621 Direct .o file writing support for darwin/x86[-64] is now reliable and
622 support for other targets and object file formats are in progress.</li>
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]623</ul>
Chris Lattnerdc910082010-03-17 06:41:58 +0000[diff] [blame]624
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]625</div>
626
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]627<!--=========================================================================-->
628<div class="doc_subsection">
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]629<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]630</div>
631
632<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]633<p>LLVM IR has several new features for better support of new targets and that
634expose new optimization opportunities:</p>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]635
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]636<ul>
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]637<li>The <a href="LangRef.html#int_libc">memcpy, memmove, and memset</a>
638 intrinsics now take address space qualified pointers and a bit to indicate
639 whether the transfer is "<a href="LangRef.html#volatile">volatile</a>" or not.
640</li>
641<li>Per-instruction debug info metadata is much faster and uses less memory by
642 using the new DebugLoc class.</li>
643<li>LLVM IR now has a more formalized concept of "<a
644 href="LangRef.html#trapvalues">trap values</a>", which allow the optimizer
645 to optimize more aggressively in the presence of undefined behavior, while
646 still producing predictable results.</li>
647<li>LLVM IR now supports two new <a href="LangRef.html#linkage">linkage
648 types</a> (linker_private_weak and linker_private_weak_def_auto) which map
649 onto some obscure MachO concepts.</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]650</ul>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]651
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]652</div>
653
654<!--=========================================================================-->
655<div class="doc_subsection">
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]656<a name="optimizer">Optimizer Improvements</a>
657</div>
658
659<div class="doc_text">
660
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]661<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattnerf3013872008-10-13 21:50:36 +0000[diff] [blame]662release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]663
664<ul>
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]665<li>As mentioned above, the optimizer now has support for updating debug
666 information as it goes. A key aspect of this is the new <a
667 href="SourceLevelDebugging.html#format_common_value">llvm.dbg.value</a>
668 intrinsic. This intrinsic represents debug info for variables that are
669 promoted to SSA values (typically by mem2reg or the -scalarrepl passes).</li>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]670
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]671<li>The JumpThreading pass is now much more aggressive about implied value
672 relations, allowing it to thread conditions like "a == 4" when a is known to
673 be 13 in one of the predecessors of a block. It does this in conjunction
674 with the new LazyValueInfo analysis pass.</li>
675<li>The new RegionInfo analysis pass identifies single-entry single-exit regions
Tobias Grosserf61576a2010-10-06 11:43:06 +0000[diff] [blame]676 in the CFG. You can play with it with the "opt -regions -analyze" or
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]677 "opt -view-regions" commands.</li>
Duncan Sands30be9e42010-10-04 10:04:14 +0000[diff] [blame]678<li>The loop optimizer has significantly improved strength reduction and analysis
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]679 capabilities. Notably it is able to build on the trap value and signed
680 integer overflow information to optimize &lt;= and &gt;= loops.</li>
681<li>The CallGraphSCCPassManager now has some basic support for iterating within
682 an SCC when a optimizer devirtualizes a function call. This allows inlining
683 through indirect call sites that are devirtualized by store-load forwarding
684 and other optimizations.</li>
685<li>The new <A href="Passes.html#loweratomic">-loweratomic</a> pass is available
686 to lower atomic instructions into their non-atomic form. This can be useful
687 to optimize generic code that expects to run in a single-threaded
688 environment.</li>
689</ul>
690
691<!--
692<p>In addition to these features that are done in 2.8, there is preliminary
693 support in the release for Type Based Alias Analysis
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]694 Preliminary work on TBAA but not usable in 2.8.
695 New CorrelatedValuePropagation pass, not on by default in 2.8 yet.
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]696-->
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]697
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]698</div>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]699
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]700<!--=========================================================================-->
701<div class="doc_subsection">
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]702<a name="mc">MC Level Improvements</a>
703</div>
704
705<div class="doc_text">
706<p>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]707The LLVM Machine Code (aka MC) subsystem was created to solve a number
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]708of problems in the realm of assembly, disassembly, object file format handling,
709and a number of other related areas that CPU instruction-set level tools work
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]710in.</p>
711
712<p>The MC subproject has made great leaps in LLVM 2.8. For example, support for
713 directly writing .o files from LLC (and clang) now works reliably for
714 darwin/x86[-64] (including inline assembly support) and the integrated
715 assembler is turned on by default in Clang for these targets. This provides
716 improved compile times among other things.</p>
717
718<ul>
719<li>The entire compiler has converted over to using the MCStreamer assembler API
720 instead of writing out a .s file textually.</li>
721<li>The "assembler parser" is far more mature than in 2.7, supporting a full
722 complement of directives, now supports assembler macros, etc.</li>
723<li>The "assembler backend" has been completed, including support for relaxation
724 relocation processing and all the other things that an assembler does.</li>
725<li>The MachO file format support is now fully functional and works.</li>
726<li>The MC disassembler now fully supports ARM and Thumb. ARM assembler support
727 is still in early development though.</li>
728<li>The X86 MC assembler now supports the X86 AES and AVX instruction set.</li>
Chris Lattner3bdcda12010-10-04 03:58:12 +0000[diff] [blame]729<li>Work on ELF and COFF object files and ARM target support is well underway,
730 but isn't useful yet in LLVM 2.8. Please contact the llvmdev mailing list
731 if you're interested in this.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]732</ul>
733
734<p>For more information, please see the <a
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]735href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
736LLVM MC Project Blog Post</a>.
737</p>
738
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]739</div>
740
741
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]742<!--=========================================================================-->
743<div class="doc_subsection">
Chris Lattner511433e2009-03-02 03:24:11 +0000[diff] [blame]744<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]745</div>
746
747<div class="doc_text">
748
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]749<p>We have put a significant amount of work into the code generator
750infrastructure, which allows us to implement more aggressive algorithms and make
751it run faster:</p>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]752
753<ul>
Chris Lattner3bdcda12010-10-04 03:58:12 +0000[diff] [blame]754<li>The clang/gcc -momit-leaf-frame-pointer argument is now supported.</li>
755<li>The clang/gcc -ffunction-sections and -fdata-sections arguments are now
756 supported on ELF targets (like GCC).</li>
757<li>The MachineCSE pass is now tuned and on by default. It eliminates common
758 subexpressions that are exposed when lowering to machine instructions.</li>
759<li>The "local" register allocator was replaced by a new "fast" register
760 allocator. This new allocator (which is often used at -O0) is substantially
761 faster and produces better code than the old local register allocator.</li>
762<li>A new LLC "-regalloc=default" option is available, which automatically
763 chooses a register allocator based on the -O optimization level.</li>
764<li>The common code generator code was modified to promote illegal argument and
765 return value vectors to wider ones when possible instead of scalarizing
766 them. For example, &lt;3 x float&gt; will now pass in one SSE register
767 instead of 3 on X86. This generates substantially better code since the
768 rest of the code generator was already expecting this.</li>
769<li>The code generator uses a new "COPY" machine instruction. This speeds up
770 the code generator and eliminates the need for targets to implement the
771 isMoveInstr hook. Also, the copyRegToReg hook was renamed to copyPhysReg
772 and simplified.</li>
773<li>The code generator now has a "LocalStackSlotPass", which optimizes stack
774 slot access for targets (like ARM) that have limited stack displacement
775 addressing.</li>
776<li>A new "PeepholeOptimizer" is available, which eliminates sign and zero
777 extends, and optimizes away compare instructions when the condition result
778 is available from a previous instruction.</li>
779<li>Atomic operations now get legalized into simpler atomic operations if not
Duncan Sands30be9e42010-10-04 10:04:14 +0000[diff] [blame]780 natively supported, easing the implementation burden on targets.</li>
Chris Lattnerb822f652010-10-04 16:46:07 +0000[diff] [blame]781<li>We have added two new bottom-up pre-allocation register pressure aware schedulers:
782<ol>
783<li>The hybrid scheduler schedules aggressively to minimize schedule length when registers are available and avoid overscheduling in high pressure situations.</li>
784<li>The instruction-level-parallelism scheduler schedules for maximum ILP when registers are available and avoid overscheduling in high pressure situations.</li>
785</ol></li>
Chris Lattner3bdcda12010-10-04 03:58:12 +0000[diff] [blame]786<li>The tblgen type inference algorithm was rewritten to be more consistent and
787 diagnose more target bugs. If you have an out-of-tree backend, you may
788 find that it finds bugs in your target description. This support also
789 allows limited support for writing patterns for instructions that return
790 multiple results (e.g. a virtual register and a flag result). The
791 'parallel' modifier in tblgen was removed, you should use the new support
792 for multiple results instead.</li>
793<li>A new (experimental) "-rendermf" pass is available which renders a
794 MachineFunction into HTML, showing live ranges and other useful
795 details.</li>
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame]796<li>The new SubRegIndex tablegen class allows subregisters to be indexed
797 symbolically instead of numerically. If your target uses subregisters you
798 will need to adapt to use SubRegIndex when you upgrade to 2.8.</li>
Chris Lattner3bdcda12010-10-04 03:58:12 +0000[diff] [blame]799<!-- SplitKit -->
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]800
Chris Lattner3bdcda12010-10-04 03:58:12 +0000[diff] [blame]801<li>The -fast-isel instruction selection path (used at -O0 on X86) was rewritten
802 to work bottom-up on basic blocks instead of top down. This makes it
803 slightly faster (because the MachineDCE pass is not needed any longer) and
804 allows it to generate better code in some cases.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]805
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]806</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]807</div>
808
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]809<!--=========================================================================-->
810<div class="doc_subsection">
811<a name="x86">X86-32 and X86-64 Target Improvements</a>
812</div>
813
814<div class="doc_text">
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame]815<p>New features and major changes in the X86 target include:
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]816</p>
817
818<ul>
Chris Lattner922d00f2010-07-21 15:57:40 +0000[diff] [blame]819<li>The X86 backend now supports holding X87 floating point stack values
820 in registers across basic blocks, dramatically improving performance of code
Gabor Greif9f459132010-10-04 17:03:49 +0000[diff] [blame]821 that uses long double, and when targeting CPUs that don't support SSE.</li>
Chris Lattner511433e2009-03-02 03:24:11 +0000[diff] [blame]822
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame]823<li>The X86 backend now uses a SSEDomainFix pass to optimize SSE operations. On
824 Nehalem ("Core i7") and newer CPUs there is a 2 cycle latency penalty on
825 using a register in a different domain than where it was defined. This pass
826 optimizes away these stalls.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]827
Duncan Sands30be9e42010-10-04 10:04:14 +0000[diff] [blame]828<li>The X86 backend now promotes 16-bit integer operations to 32-bits when
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame]829 possible. This avoids 0x66 prefixes, which are slow on some
830 microarchitectures and bloat the code on all of them.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]831
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame]832<li>The X86 backend now supports the Microsoft "thiscall" calling convention,
833 and a <a href="LangRef.html#callingconv">calling convention</a> to support
834 <a href="#GHC">ghc</a>.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]835
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame]836<li>The X86 backend supports a new "llvm.x86.int" intrinsic, which maps onto
837 the X86 "int $42" and "int3" instructions.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]838
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame]839<li>At the IR level, the &lt;2 x float&gt; datatype is now promoted and passed
Duncan Sands30be9e42010-10-04 10:04:14 +0000[diff] [blame]840 around as a &lt;4 x float&gt; instead of being passed and returned as an MMX
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame]841 vector. If you have a frontend that uses this, please pass and return a
842 &lt;2 x i32&gt; instead (using bitcasts).</li>
843
844<li>When printing .s files in verbose assembly mode (the default for clang -S),
845 the X86 backend now decodes X86 shuffle instructions and prints human
Gabor Greif9f459132010-10-04 17:03:49 +0000[diff] [blame]846 readable comments after the most inscrutable of them, e.g.:
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame]847
848<pre>
849 insertps $113, %xmm3, %xmm0 <i># xmm0 = zero,xmm0[1,2],xmm3[1]</i>
850 unpcklps %xmm1, %xmm0 <i># xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1]</i>
851 pshufd $1, %xmm1, %xmm1 <i># xmm1 = xmm1[1,0,0,0]</i>
852</pre>
853</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]854
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]855</ul>
856
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]857</div>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]858
859<!--=========================================================================-->
860<div class="doc_subsection">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]861<a name="ARM">ARM Target Improvements</a>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]862</div>
863
864<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]865<p>New features of the ARM target include:
866</p>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]867
868<ul>
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame]869<li>The ARM backend now optimizes tail calls into jumps.</li>
870<li>Scheduling is improved through the new list-hybrid scheduler as well
871 as through better modeling of structural hazards.</li>
872<li><a href="LangRef.html#int_fp16">Half float</a> instructions are now
873 supported.</li>
874<li>NEON support has been improved to model instructions which operate onto
Duncan Sands30be9e42010-10-04 10:04:14 +0000[diff] [blame]875 multiple consecutive registers more aggressively. This avoids lots of
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame]876 extraneous register copies.</li>
877<li>The ARM backend now uses a new "ARMGlobalMerge" pass, which merges several
878 global variables into one, saving extra address computation (all the global
879 variables can be accessed via same base address) and potentially reducing
880 register pressure.</li>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]881
Jim Grosbach894a1b12010-10-05 01:00:42 +0000[diff] [blame]882<li>The ARM backend has received many minor improvements and tweaks which lead
883 to substantially better performance in a wide range of different scenarios.
884</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]885
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]886<li>The ARM NEON intrinsics have been substantially reworked to reduce
887 redundancy and improve code generation. Some of the major changes are:
888 <ol>
889 <li>
890 All of the NEON load and store intrinsics (llvm.arm.neon.vld* and
891 llvm.arm.neon.vst*) take an extra parameter to specify the alignment in bytes
892 of the memory being accessed.
893 </li>
894 <li>
895 The llvm.arm.neon.vaba intrinsic (vector absolute difference and
896 accumulate) has been removed. This operation is now represented using
897 the llvm.arm.neon.vabd intrinsic (vector absolute difference) followed by a
898 vector add.
899 </li>
900 <li>
901 The llvm.arm.neon.vabdl and llvm.arm.neon.vabal intrinsics (lengthening
Gabor Greif9f459132010-10-04 17:03:49 +0000[diff] [blame]902 vector absolute difference with and without accumulation) have been removed.
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]903 They are represented using the llvm.arm.neon.vabd intrinsic (vector absolute
904 difference) followed by a vector zero-extend operation, and for vabal,
905 a vector add.
906 </li>
907 <li>
908 The llvm.arm.neon.vmovn intrinsic has been removed. Calls of this intrinsic
909 are now replaced by vector truncate operations.
910 </li>
911 <li>
912 The llvm.arm.neon.vmovls and llvm.arm.neon.vmovlu intrinsics have been
913 removed. They are now represented as vector sign-extend (vmovls) and
914 zero-extend (vmovlu) operations.
915 </li>
916 <li>
917 The llvm.arm.neon.vaddl*, llvm.arm.neon.vaddw*, llvm.arm.neon.vsubl*, and
918 llvm.arm.neon.vsubw* intrinsics (lengthening vector add and subtract) have
919 been removed. They are replaced by vector add and vector subtract operations
920 where one (vaddw, vsubw) or both (vaddl, vsubl) of the operands are either
921 sign-extended or zero-extended.
922 </li>
923 <li>
924 The llvm.arm.neon.vmulls, llvm.arm.neon.vmullu, llvm.arm.neon.vmlal*, and
925 llvm.arm.neon.vmlsl* intrinsics (lengthening vector multiply with and without
926 accumulation and subtraction) have been removed. These operations are now
927 represented as vector multiplications where the operands are either
928 sign-extended or zero-extended, followed by a vector add for vmlal or a
929 vector subtract for vmlsl. Note that the polynomial vector multiply
930 intrinsic, llvm.arm.neon.vmullp, remains unchanged.
931 </li>
932 </ol>
Bob Wilson5b2fb952010-09-13 17:37:55 +0000[diff] [blame]933</li>
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame]934
Bob Wilsone8472772010-09-13 17:39:35 +0000[diff] [blame]935</ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]936</div>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]937
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]938
939<!--=========================================================================-->
940<div class="doc_subsection">
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]941<a name="changes">Major Changes and Removed Features</a>
942</div>
943
944<div class="doc_text">
945
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]946<p>If you're already an LLVM user or developer with out-of-tree changes based
Chris Lattner922d00f2010-07-21 15:57:40 +0000[diff] [blame]947on LLVM 2.7, this section lists some "gotchas" that you may run into upgrading
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]948from the previous release.</p>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]949
950<ul>
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]951<li>The build configuration machinery changed the output directory names. It
Duncan Sands30be9e42010-10-04 10:04:14 +0000[diff] [blame]952 wasn't clear to many people that a "Release-Asserts" build was a release build
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]953 without asserts. To make this more clear, "Release" does not include
954 assertions and "Release+Asserts" does (likewise, "Debug" and
955 "Debug+Asserts").</li>
956<li>The MSIL Backend was removed, it was unsupported and broken.</li>
957<li>The ABCD, SSI, and SCCVN passes were removed. These were not fully
958 functional and their behavior has been or will be subsumed by the
959 LazyValueInfo pass.</li>
960<li>The LLVM IR 'Union' feature was removed. While this is a desirable feature
961 for LLVM IR to support, the existing implementation was half baked and
962 barely useful. We'd really like anyone interested to resurrect the work and
963 finish it for a future release.</li>
964<li>If you're used to reading .ll files, you'll probably notice that .ll file
965 dumps don't produce #uses comments anymore. To get them, run a .bc file
966 through "llvm-dis --show-annotations".</li>
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]967<li>Target triples are now stored in a normalized form, and all inputs from
968 humans are expected to be normalized by Triple::normalize before being
969 stored in a module triple or passed to another library.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]970</ul>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]971
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]972
973
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]974<p>In addition, many APIs have changed in this release. Some of the major LLVM
975API changes are:</p>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]976<ul>
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]977<li>LLVM 2.8 changes the internal order of operands in <a
978 href="http://llvm.org/doxygen/classllvm_1_1InvokeInst.html"><tt>InvokeInst</tt></a>
979 and <a href="http://llvm.org/doxygen/classllvm_1_1CallInst.html"><tt>CallInst</tt></a>.
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]980 To be portable across releases, please use the <tt>CallSite</tt> class and the
981 high-level accessors, such as <tt>getCalledValue</tt> and
982 <tt>setUnwindDest</tt>.
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]983</li>
984<li>
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]985 You can no longer pass use_iterators directly to cast&lt;&gt; (and similar),
986 because these routines tend to perform costly dereference operations more
987 than once. You have to dereference the iterators yourself and pass them in.
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]988</li>
989<li>
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]990 llvm.memcpy.*, llvm.memset.*, llvm.memmove.* intrinsics take an extra
991 parameter now ("i1 isVolatile"), totaling 5 parameters, and the pointer
992 operands are now address-space qualified.
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]993 If you were creating these intrinsic calls and prototypes yourself (as opposed
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]994 to using Intrinsic::getDeclaration), you can use
Gabor Greif9f459132010-10-04 17:03:49 +0000[diff] [blame]995 UpgradeIntrinsicFunction/UpgradeIntrinsicCall to be portable across releases.
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]996</li>
997<li>
998 SetCurrentDebugLocation takes a DebugLoc now instead of a MDNode.
999 Change your code to use
1000 SetCurrentDebugLocation(DebugLoc::getFromDILocation(...)).
1001</li>
1002<li>
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]1003 The <tt>RegisterPass</tt> and <tt>RegisterAnalysisGroup</tt> templates are
1004 considered deprecated, but continue to function in LLVM 2.8. Clients are
1005 strongly advised to use the upcoming <tt>INITIALIZE_PASS()</tt> and
1006 <tt>INITIALIZE_AG_PASS()</tt> macros instead.
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]1007</li>
1008<li>
1009 The constructor for the Triple class no longer tries to understand odd triple
1010 specifications. Frontends should ensure that they only pass valid triples to
1011 LLVM. The Triple::normalize utility method has been added to help front-ends
1012 deal with funky triples.
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]1013</li>
1014
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]1015<li>
Daniel Dunbarf2c13ef2010-10-04 20:11:39 +0000[diff] [blame]1016 Some APIs were renamed:
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]1017 <ul>
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]1018 <li>llvm_report_error -&gt; report_fatal_error</li>
1019 <li>llvm_install_error_handler -&gt; install_fatal_error_handler</li>
1020 <li>llvm::DwarfExceptionHandling -&gt; llvm::JITExceptionHandling</li>
1021 <li>VISIBILITY_HIDDEN -&gt; LLVM_LIBRARY_VISIBILITY</li>
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]1022 </ul>
1023</li>
1024
Daniel Dunbarf2c13ef2010-10-04 20:11:39 +0000[diff] [blame]1025<li>
1026 Some public headers were renamed:
1027 <ul>
1028 <li><tt>llvm/Assembly/AsmAnnotationWriter.h</tt> was renamed
1029 to <tt>llvm/Assembly/AssemblyAnnotationWriter.h</tt>
1030 </li>
1031 </ul>
Devang Patelb34dd132008-10-14 20:03:43 +0000[diff] [blame]1032</ul>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]1033
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]1034</div>
1035
Daniel Dunbarf0233c62010-10-04 20:11:41 +0000[diff] [blame]1036<!--=========================================================================-->
1037<div class="doc_subsection">
1038<a name="devtree_changes">Development Infrastructure Changes</a>
1039</div>
1040
1041<div class="doc_text">
1042
1043<p>This section lists changes to the LLVM development infrastructure. This
1044mostly impacts users who actively work on LLVM or follow development on
1045mainline, but may also impact users who leverage the LLVM build infrastructure
1046or are interested in LLVM qualification.</p>
1047
1048<ul>
1049 <li>The default for <tt>make check</tt> is now to use
1050 the <a href="http://llvm.org/cmds/lit.html">lit</a> testing tool, which is
1051 part of LLVM itself. You can use <tt>lit</tt> directly as well, or use
1052 the <tt>llvm-lit</tt> tool which is created as part of a Makefile or CMake
1053 build (and knows how to find the appropriate tools). See the <tt>lit</tt>
1054 documentation and the <a href="http://blog.llvm.org/2009/12/lit-it.html">blog
1055 post</a>, and <a href="http://llvm.org/bugs/show_bug.cgi?id=5217">PR5217</a>
1056 for more information.</li>
1057
1058 <li>The LLVM <tt>test-suite</tt> infrastructure has a new "simple" test format
1059 (<tt>make TEST=simple</tt>). The new format is intended to require only a
1060 compiler and not a full set of LLVM tools. This makes it useful for testing
1061 released compilers, for running the test suite with other compilers (for
1062 performance comparisons), and makes sure that we are testing the compiler as
1063 users would see it. The new format is also designed to work using reference
1064 outputs instead of comparison to a baseline compiler, which makes it run much
1065 faster and makes it less system dependent.</li>
1066
1067 <li>Significant progress has been made on a new interface to running the
1068 LLVM <tt>test-suite</tt> (aka the LLVM "nightly tests") using
1069 the <a href="http://llvm.org/docs/lnt">LNT</a> infrastructure. The LNT
1070 interface to the <tt>test-suite</tt> brings significantly improved reporting
1071 capabilities for monitoring the correctness and generated code quality
1072 produced by LLVM over time.</li>
1073</ul>
1074</div>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]1075
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1076<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1077<div class="doc_section">
1078 <a name="knownproblems">Known Problems</a>
1079</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1080<!-- *********************************************************************** -->
1081
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1082<div class="doc_text">
1083
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]1084<p>This section contains significant known problems with the LLVM system,
Chris Lattnere18b32e2008-11-10 05:40:34 +0000[diff] [blame]1085listed by component. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]1086href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]1087there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1088
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1089</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1090
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]1091<!-- ======================================================================= -->
1092<div class="doc_subsection">
1093 <a name="experimental">Experimental features included with this release</a>
1094</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1095
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]1096<div class="doc_text">
1097
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]1098<p>The following components of this LLVM release are either untested, known to
1099be broken or unreliable, or are in early development. These components should
1100not be relied on, and bugs should not be filed against them, but they may be
1101useful to some people. In particular, if you would like to work on one of these
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1102components, please contact us on the <a
1103href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]1104
1105<ul>
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]1106<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, PIC16, SystemZ
1107 and XCore backends are experimental.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]1108<li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets
1109 other than darwin-i386 and darwin-x86_64.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]1110</ul>
1111
1112</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1113
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1114<!-- ======================================================================= -->
1115<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1116 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]1117</div>
1118
1119<div class="doc_text">
1120
1121<ul>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]1122 <li>The X86 backend does not yet support
1123 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
1124 floating point stack</a>. It supports the 'f' and 't' constraints, but not
1125 'u'.</li>
Duncan Sands47eff2b2008-06-08 19:38:43 +0000[diff] [blame]1126 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]1127 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]1128 runtime currently due to lack of support for the 'u' inline assembly
1129 constraint and for X87 floating point inline assembly.</li>
Dan Gohman8207ba92008-06-08 23:05:11 +0000[diff] [blame]1130 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]1131 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman8207ba92008-06-08 23:05:11 +0000[diff] [blame]1132 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1133</ul>
1134
1135</div>
1136
1137<!-- ======================================================================= -->
1138<div class="doc_subsection">
1139 <a name="ppc-be">Known problems with the PowerPC back-end</a>
1140</div>
1141
1142<div class="doc_text">
1143
1144<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000[diff] [blame]1145<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]1146compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1147</ul>
1148
1149</div>
1150
1151<!-- ======================================================================= -->
1152<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]1153 <a name="arm-be">Known problems with the ARM back-end</a>
1154</div>
1155
1156<div class="doc_text">
1157
1158<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]1159<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000[diff] [blame]1160processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]1161results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]1162<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]1163</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]1164</ul>
1165
1166</div>
1167
1168<!-- ======================================================================= -->
1169<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1170 <a name="sparc-be">Known problems with the SPARC back-end</a>
1171</div>
1172
1173<div class="doc_text">
1174
1175<ul>
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]1176<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1177 support the 64-bit SPARC ABI (-m64).</li>
1178</ul>
1179
1180</div>
1181
1182<!-- ======================================================================= -->
1183<div class="doc_subsection">
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000[diff] [blame]1184 <a name="mips-be">Known problems with the MIPS back-end</a>
1185</div>
1186
1187<div class="doc_text">
1188
1189<ul>
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000[diff] [blame]1190<li>64-bit MIPS targets are not supported yet.</li>
1191</ul>
1192
1193</div>
1194
1195<!-- ======================================================================= -->
1196<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1197 <a name="alpha-be">Known problems with the Alpha back-end</a>
1198</div>
1199
1200<div class="doc_text">
1201
1202<ul>
1203
1204<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
1205appropriate nops inserted to ensure restartability.</li>
1206
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]1207</ul>
1208</div>
1209
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1210<!-- ======================================================================= -->
1211<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]1212 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1213</div>
1214
1215<div class="doc_text">
1216
Chris Lattner3016ee92010-09-29 05:34:42 +0000[diff] [blame]1217<p>The C backend has numerous problems and is not being actively maintained.
1218Depending on it for anything serious is not advised.</p>
1219
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1220<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]1221<li><a href="http://llvm.org/PR802">The C backend has only basic support for
1222 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000[diff] [blame]1223<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
1224 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif4906abe2009-03-02 12:02:51 +0000[diff] [blame]1225 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]1226<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands50723a92009-02-25 11:51:54 +0000[diff] [blame]1227<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1228</ul>
1229
1230</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]1231
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1232
1233<!-- ======================================================================= -->
1234<div class="doc_subsection">
Chris Lattner3016ee92010-09-29 05:34:42 +0000[diff] [blame]1235 <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1236</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]1237
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1238<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]1239
Chris Lattner3016ee92010-09-29 05:34:42 +0000[diff] [blame]1240<p>llvm-gcc is generally very stable for the C family of languages. The only
1241 major language feature of GCC not supported by llvm-gcc is the
1242 <tt>__builtin_apply</tt> family of builtins. However, some extensions
1243 are only supported on some targets. For example, trampolines are only
1244 supported on some targets (these are used when you take the address of a
1245 nested function).</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1246
Chris Lattner3016ee92010-09-29 05:34:42 +0000[diff] [blame]1247<p>Fortran support generally works, but there are still several unresolved bugs
1248 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
1249 tools/gfortran component for details. Note that llvm-gcc is missing major
1250 Fortran performance work in the frontend and library that went into GCC after
1251 4.2. If you are interested in Fortran, we recommend that you consider using
1252 <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1253
Duncan Sands3af96332010-10-04 10:06:56 +0000[diff] [blame]1254<p>The llvm-gcc 4.2 Ada compiler has basic functionality, but is no longer being
1255actively maintained. If you are interested in Ada, we recommend that you
1256consider using <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1257</div>
1258
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1259<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1260<div class="doc_section">
1261 <a name="additionalinfo">Additional Information</a>
1262</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1263<!-- *********************************************************************** -->
1264
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1265<div class="doc_text">
1266
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]1267<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]1268href="http://llvm.org">LLVM web page</a>, in particular in the <a
1269href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]1270contains versions of the API documentation which is up-to-date with the
1271Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]1272You can access versions of these documents specific to this release by going
1273into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1274
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1275<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]1276us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]1277lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1278
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1279</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1280
1281<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1282
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1283<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]1284<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]1285 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]1286 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]1287 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]1288 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]1289
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]1290 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1291 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]1292</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1293
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1294</body>
1295</html>