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gerrit-public.fairphone.software / toolchain / llvm-project / a11e9827b1c83d8193b0f72134add936cacafa13 / . / llvm / docs / ReleaseNotes.html
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4<head>
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Dan Gohman62af9d22010-05-03 23:51:05 +0000[diff] [blame]8 <title>LLVM 2.8 Release Notes</title>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]9</head>
10<body>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]11
Dan Gohman62af9d22010-05-03 23:51:05 +0000[diff] [blame]12<div class="doc_title">LLVM 2.8 Release Notes</div>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]13
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]14<img align=right src="http://llvm.org/img/DragonSmall.png"
Gabor Greif27b166352010-04-22 10:21:43 +0000[diff] [blame]15 width="136" height="136" alt="LLVM Dragon Logo">
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]16
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]17<ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]18 <li><a href="#intro">Introduction</a></li>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]19 <li><a href="#subproj">Sub-project Status Update</a></li>
Dan Gohman62af9d22010-05-03 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 Lattner77a51732004-04-30 22:17:12 +0000[diff] [blame]22 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Dan Gohmanad888912008-10-14 16:23:02 +0000[diff] [blame]23 <li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]24 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]25</ol>
26
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]27<div class="doc_author">
Dan Gohmanad888912008-10-14 16:23:02 +0000[diff] [blame]28 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]29</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]30
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]31<!--
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]32<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.8
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]33release.<br>
34You may prefer the
Dan Gohman62af9d22010-05-03 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 Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]37-->
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]38
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]39<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]40<div class="doc_section">
41 <a name="intro">Introduction</a>
42</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]43<!-- *********************************************************************** -->
44
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]45<div class="doc_text">
46
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]47<p>This document contains the release notes for the LLVM Compiler
Dan Gohman3b763f42010-05-03 23:52:21 +0000[diff] [blame]48Infrastructure, release 2.8. Here we describe the status of LLVM, including
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]49major improvements from the previous release and significant known problems.
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]50All LLVM releases may be downloaded from the <a
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]51href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]52
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]53<p>For more information about LLVM, including information about the latest
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]54release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattnere7525b52003-10-07 21:38:31 +0000[diff] [blame]55web site</a>. If you have questions or comments, the <a
Chris Lattner0b1c9a52010-03-17 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 Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]58
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]59<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]60main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greif355f81c2008-10-14 11:00:32 +0000[diff] [blame]61current one. To see the release notes for a specific release, please see the
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]62<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]63
64</div>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]65
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]66
Chris Lattneraa61f412009-10-13 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 Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]71 GEPSplitterPass
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]72-->
73
74
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]75<!-- Features that need text if they're finished for 2.9:
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]76 combiner-aa?
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]77 strong phi elim
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]78 loop dependence analysis
Chris Lattnerbd244042010-08-28 16:33:36 +0000[diff] [blame]79 TBAA
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]80 CorrelatedValuePropagation
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]81 -->
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]82
83 <!-- Announcement, lldb, libc++ -->
Chris Lattner16be34d2010-09-29 07:25:03 +0000[diff] [blame]84
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]85
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]86<!-- *********************************************************************** -->
87<div class="doc_section">
88 <a name="subproj">Sub-project Status Update</a>
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]89</div>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]90<!-- *********************************************************************** -->
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]91
92<div class="doc_text">
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]93<p>
Dan Gohman62af9d22010-05-03 23:51:05 +0000[diff] [blame]94The LLVM 2.8 distribution currently consists of code from the core LLVM
Chris Lattneraa61f412009-10-13 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 Wendlingf170d2e2009-03-02 04:28:57 +0000[diff] [blame]99</p>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]100
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]101</div>
102
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]103
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]104<!--=========================================================================-->
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]105<div class="doc_subsection">
Chris Lattner44c09cd2008-10-13 18:11:54 +0000[diff] [blame]106<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]107</div>
108
109<div class="doc_text">
110
Chris Lattner5de7f6e2010-04-26 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 Lattner342f9572010-09-29 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 Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]119
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]120<p>In the LLVM 2.8 time-frame, the Clang team has made many improvements:</p>
Bill Wendlingef362462008-10-27 09:27:33 +0000[diff] [blame]121
Douglas Gregor614ace62010-10-04 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 Lopes3ae4d872010-10-04 22:07:22 +0000[diff] [blame]129 <li>Added support for SSE, AVX, ARM NEON, and AltiVec.</li>
Daniel Dunbar60ad0092010-10-04 17:06:49 +0000[diff] [blame]130 <li>Improved support for many Microsoft extensions.</li>
Douglas Gregor614ace62010-10-04 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 Dunbar60ad0092010-10-04 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 Gregor614ace62010-10-04 07:02:35 +0000[diff] [blame]142 </ul>
Chris Lattner44c09cd2008-10-13 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 Lattner2284b6a2010-04-22 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 Lattnerbcffa5a2008-10-14 00:52:49 +0000[diff] [blame]158
Chris Lattner3458ab62010-09-30 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 Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]161</p>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]162
163</div>
164
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]165<!--=========================================================================-->
166<div class="doc_subsection">
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]167<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]168</div>
169
170<div class="doc_text">
171<p>
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]172<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
Duncan Sands7f9a0dc2010-09-30 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 Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]178</p>
179
180<p>
Duncan Sands7f9a0dc2010-09-30 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 Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]186</p>
187
188<p>
Duncan Sands7f9a0dc2010-09-30 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 Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]200
201</div>
202
Chris Lattner120804a2010-10-03 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 Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]242
243<!--=========================================================================-->
244<div class="doc_subsection">
Chris Lattner342f9572010-09-29 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 Lattner120804a2010-10-03 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 Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]255
256<p>
Chris Lattner120804a2010-10-03 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 Lattner342f9572010-09-29 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>
Tobias Grosser436bc5f2010-10-06 21:07:30 +0000[diff] [blame]272<a href="http://libcxx.llvm.org/">libc++</a> is another new member of the LLVM
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]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 Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]276
277<p>
Chris Lattner120804a2010-10-03 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 Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]281</p>
282
283</div>
284
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]285
Daniel Dunbar8fbd8aa2010-10-04 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 Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]323<!-- *********************************************************************** -->
324<div class="doc_section">
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]325 <a name="externalproj">External Open Source Projects Using LLVM 2.8</a>
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]326</div>
327<!-- *********************************************************************** -->
328
Chris Lattneraa61f412009-10-13 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 Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]333 projects that have already been updated to work with LLVM 2.8.</p>
Chris Lattnerdf85c892010-04-26 17:38:10 +0000[diff] [blame]334</div>
335
Chris Lattner3458ab62010-09-30 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 Greifdcdbbea32010-10-04 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 Lattner3458ab62010-09-30 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 Greif0d4224e2010-10-04 17:54:30 +0000[diff] [blame]381<a href="http://www.clamav.net">Clam AntiVirus</a> is an open source (GPL)
Chris Lattner3458ab62010-09-30 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 Greifdcdbbea32010-10-04 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 Lattner3458ab62010-09-30 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 Lattner510a81a2010-09-30 01:12:09 +0000[diff] [blame]448<a href="http://tachyon.in/clay/">Clay</a> is a new systems programming
Chris Lattner3458ab62010-09-30 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 Lattner64694df2010-04-22 21:34:16 +0000[diff] [blame]454
Chris Lattnerca7c8962010-10-01 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 Lattnerd93b4af2010-10-03 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 Sands6ad8bf62010-10-04 10:04:14 +0000[diff] [blame]498RVC-CAL language and a dataflow configuration &#8212; block diagram &#8212;
Chris Lattnerd93b4af2010-10-03 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 Greifdcdbbea32010-10-04 17:03:49 +0000[diff] [blame]546<code>__transaction { list.remove(x); x.refCount--; }</code>) and will be executed
Chris Lattnerd93b4af2010-10-03 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 Lattnerc3e64b22010-10-04 16:06:37 +0000[diff] [blame]553<a name="Kai">Kai Programming Language</a>
Chris Lattnerd93b4af2010-10-03 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 Lattner120804a2010-10-03 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 Lattnerca7c8962010-10-01 06:34:49 +0000[diff] [blame]587
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]588<!-- *********************************************************************** -->
589<div class="doc_section">
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]590 <a name="whatsnew">What's New in LLVM 2.8?</a>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]591</div>
592<!-- *********************************************************************** -->
593
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]594<div class="doc_text">
595
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]596<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]597minor improvements. Some of the major improvements and new features are listed
598in this section.
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]599</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]600
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]601</div>
602
603<!--=========================================================================-->
604<div class="doc_subsection">
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]605<a name="majorfeatures">Major New Features</a>
606</div>
607
608<div class="doc_text">
609
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]610<p>LLVM 2.8 includes several major new capabilities:</p>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]611
612<ul>
Chris Lattnerfcc65a72010-10-04 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 Lattnerfcc65a72010-10-04 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 Lattner458e79f2008-02-10 08:18:42 +0000[diff] [blame]623</ul>
Chris Lattner10a3cc42010-03-17 06:41:58 +0000[diff] [blame]624
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]625</div>
626
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]627<!--=========================================================================-->
628<div class="doc_subsection">
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]629<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]630</div>
631
632<div class="doc_text">
Chris Lattneraa61f412009-10-13 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 Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]635
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]636<ul>
Chris Lattnerfcc65a72010-10-04 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 Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]650</ul>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]651
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]652</div>
653
654<!--=========================================================================-->
655<div class="doc_subsection">
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]656<a name="optimizer">Optimizer Improvements</a>
657</div>
658
659<div class="doc_text">
660
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]661<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattner25879d72008-10-13 21:50:36 +0000[diff] [blame]662release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]663
664<ul>
Chris Lattnerfcc65a72010-10-04 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 Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]670
Chris Lattnerfcc65a72010-10-04 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 Grosser5af766b2010-10-06 11:43:06 +0000[diff] [blame]676 in the CFG. You can play with it with the "opt -regions -analyze" or
Chris Lattnerfcc65a72010-10-04 02:42:39 +0000[diff] [blame]677 "opt -view-regions" commands.</li>
Duncan Sands6ad8bf62010-10-04 10:04:14 +0000[diff] [blame]678<li>The loop optimizer has significantly improved strength reduction and analysis
Chris Lattnerfcc65a72010-10-04 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 Lattnerbf1cf672010-10-02 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 Lattnerfcc65a72010-10-04 02:42:39 +0000[diff] [blame]696-->
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]697
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]698</div>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]699
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]700<!--=========================================================================-->
701<div class="doc_subsection">
Chris Lattnerf25bc192010-09-30 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 Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]707The LLVM Machine Code (aka MC) subsystem was created to solve a number
Chris Lattnerf25bc192010-09-30 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 Lattnerbf1cf672010-10-02 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 Lattner9fd1e922010-10-04 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 Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]732</ul>
733
734<p>For more information, please see the <a
Chris Lattnerf25bc192010-09-30 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 Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]739</div>
740
741
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]742<!--=========================================================================-->
743<div class="doc_subsection">
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]744<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]745</div>
746
747<div class="doc_text">
748
Mikhail Glushenkov25422542009-03-01 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 Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]752
753<ul>
Chris Lattner9fd1e922010-10-04 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 Sands6ad8bf62010-10-04 10:04:14 +0000[diff] [blame]780 natively supported, easing the implementation burden on targets.</li>
Chris Lattnerdc38ad42010-10-04 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 Lattner9fd1e922010-10-04 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 Lattnerd3f45c82010-10-04 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 Lattner9fd1e922010-10-04 03:58:12 +0000[diff] [blame]799<!-- SplitKit -->
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]800
Chris Lattner9fd1e922010-10-04 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 Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]805
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]806</ul>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]807</div>
808
Chris Lattnerd1094e02009-03-02 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 Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]815<p>New features and major changes in the X86 target include:
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]816</p>
817
818<ul>
Chris Lattnerb3fa6bf2010-07-21 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 Greifdcdbbea32010-10-04 17:03:49 +0000[diff] [blame]821 that uses long double, and when targeting CPUs that don't support SSE.</li>
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]822
Chris Lattnerd3f45c82010-10-04 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 Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]827
Duncan Sands6ad8bf62010-10-04 10:04:14 +0000[diff] [blame]828<li>The X86 backend now promotes 16-bit integer operations to 32-bits when
Chris Lattnerd3f45c82010-10-04 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 Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]831
Chris Lattnerd3f45c82010-10-04 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 Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]835
Chris Lattnerd3f45c82010-10-04 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 Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]838
Chris Lattnerd3f45c82010-10-04 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 Sands6ad8bf62010-10-04 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 Lattnerd3f45c82010-10-04 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 Greifdcdbbea32010-10-04 17:03:49 +0000[diff] [blame]846 readable comments after the most inscrutable of them, e.g.:
Chris Lattnerd3f45c82010-10-04 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 Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]854
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]855</ul>
856
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]857</div>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]858
859<!--=========================================================================-->
860<div class="doc_subsection">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]861<a name="ARM">ARM Target Improvements</a>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]862</div>
863
864<div class="doc_text">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]865<p>New features of the ARM target include:
866</p>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]867
868<ul>
Chris Lattnerd3f45c82010-10-04 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 Sands6ad8bf62010-10-04 10:04:14 +0000[diff] [blame]875 multiple consecutive registers more aggressively. This avoids lots of
Chris Lattnerd3f45c82010-10-04 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 Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]881
Jim Grosbach1e8b44e2010-10-05 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 Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]885
Chris Lattner743bc472010-10-02 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 Greifdcdbbea32010-10-04 17:03:49 +0000[diff] [blame]902 vector absolute difference with and without accumulation) have been removed.
Chris Lattner743bc472010-10-02 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 Wilson46d65802010-09-13 17:37:55 +0000[diff] [blame]933</li>
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]934
Bob Wilsone44f2982010-09-13 17:39:35 +0000[diff] [blame]935</ul>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]936</div>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]937
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]938
939<!--=========================================================================-->
940<div class="doc_subsection">
Chris Lattner1e4d5bc2008-10-13 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 Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]946<p>If you're already an LLVM user or developer with out-of-tree changes based
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]947on LLVM 2.7, this section lists some "gotchas" that you may run into upgrading
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]948from the previous release.</p>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]949
950<ul>
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]951<li>The build configuration machinery changed the output directory names. It
Duncan Sands6ad8bf62010-10-04 10:04:14 +0000[diff] [blame]952 wasn't clear to many people that a "Release-Asserts" build was a release build
Chris Lattnera7f45cf2010-10-04 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 Lattnerfcc65a72010-10-04 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 Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]970</ul>
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]971
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]972
973
Chris Lattner934e2d42008-10-13 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 Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]976<ul>
Chris Lattner743bc472010-10-02 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 Lattnera7f45cf2010-10-04 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 Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]983</li>
984<li>
Chris Lattnera7f45cf2010-10-04 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 Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]988</li>
989<li>
Chris Lattnera7f45cf2010-10-04 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 Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]993 If you were creating these intrinsic calls and prototypes yourself (as opposed
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]994 to using Intrinsic::getDeclaration), you can use
Gabor Greifdcdbbea32010-10-04 17:03:49 +0000[diff] [blame]995 UpgradeIntrinsicFunction/UpgradeIntrinsicCall to be portable across releases.
Chris Lattner743bc472010-10-02 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 Lattner743bc472010-10-02 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 Lattner743bc472010-10-02 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 Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]1013</li>
Duncan Sandsa11e9822010-10-21 14:40:02 +0000[diff] [blame^]1014<li>
1015 The signature of the <tt>GCMetadataPrinter::finishAssembly</tt> virtual
1016 function changed: the <tt>raw_ostream</tt> and <tt>MCAsmInfo</tt> arguments
1017 were dropped. GC plugins which compute stack maps must be updated to avoid
1018 having the old definition overload the new signature.
1019</li>
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]1020
Chris Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]1021<li>
Daniel Dunbarefefb202010-10-04 20:11:39 +0000[diff] [blame]1022 Some APIs were renamed:
Chris Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]1023 <ul>
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]1024 <li>llvm_report_error -&gt; report_fatal_error</li>
1025 <li>llvm_install_error_handler -&gt; install_fatal_error_handler</li>
1026 <li>llvm::DwarfExceptionHandling -&gt; llvm::JITExceptionHandling</li>
1027 <li>VISIBILITY_HIDDEN -&gt; LLVM_LIBRARY_VISIBILITY</li>
Chris Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]1028 </ul>
1029</li>
1030
Daniel Dunbarefefb202010-10-04 20:11:39 +0000[diff] [blame]1031<li>
1032 Some public headers were renamed:
1033 <ul>
1034 <li><tt>llvm/Assembly/AsmAnnotationWriter.h</tt> was renamed
1035 to <tt>llvm/Assembly/AssemblyAnnotationWriter.h</tt>
1036 </li>
1037 </ul>
Devang Pateldbf83832008-10-14 20:03:43 +0000[diff] [blame]1038</ul>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]1039
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]1040</div>
1041
Daniel Dunbarf70898a2010-10-04 20:11:41 +0000[diff] [blame]1042<!--=========================================================================-->
1043<div class="doc_subsection">
1044<a name="devtree_changes">Development Infrastructure Changes</a>
1045</div>
1046
1047<div class="doc_text">
1048
1049<p>This section lists changes to the LLVM development infrastructure. This
1050mostly impacts users who actively work on LLVM or follow development on
1051mainline, but may also impact users who leverage the LLVM build infrastructure
1052or are interested in LLVM qualification.</p>
1053
1054<ul>
1055 <li>The default for <tt>make check</tt> is now to use
1056 the <a href="http://llvm.org/cmds/lit.html">lit</a> testing tool, which is
1057 part of LLVM itself. You can use <tt>lit</tt> directly as well, or use
1058 the <tt>llvm-lit</tt> tool which is created as part of a Makefile or CMake
1059 build (and knows how to find the appropriate tools). See the <tt>lit</tt>
1060 documentation and the <a href="http://blog.llvm.org/2009/12/lit-it.html">blog
1061 post</a>, and <a href="http://llvm.org/bugs/show_bug.cgi?id=5217">PR5217</a>
1062 for more information.</li>
1063
1064 <li>The LLVM <tt>test-suite</tt> infrastructure has a new "simple" test format
1065 (<tt>make TEST=simple</tt>). The new format is intended to require only a
1066 compiler and not a full set of LLVM tools. This makes it useful for testing
1067 released compilers, for running the test suite with other compilers (for
1068 performance comparisons), and makes sure that we are testing the compiler as
1069 users would see it. The new format is also designed to work using reference
1070 outputs instead of comparison to a baseline compiler, which makes it run much
1071 faster and makes it less system dependent.</li>
1072
1073 <li>Significant progress has been made on a new interface to running the
1074 LLVM <tt>test-suite</tt> (aka the LLVM "nightly tests") using
1075 the <a href="http://llvm.org/docs/lnt">LNT</a> infrastructure. The LNT
1076 interface to the <tt>test-suite</tt> brings significantly improved reporting
1077 capabilities for monitoring the correctness and generated code quality
1078 produced by LLVM over time.</li>
1079</ul>
1080</div>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]1081
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1082<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1083<div class="doc_section">
1084 <a name="knownproblems">Known Problems</a>
1085</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1086<!-- *********************************************************************** -->
1087
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1088<div class="doc_text">
1089
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]1090<p>This section contains significant known problems with the LLVM system,
Chris Lattner2a092392008-11-10 05:40:34 +0000[diff] [blame]1091listed by component. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]1092href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]1093there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1094
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1095</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1096
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]1097<!-- ======================================================================= -->
1098<div class="doc_subsection">
1099 <a name="experimental">Experimental features included with this release</a>
1100</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1101
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]1102<div class="doc_text">
1103
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]1104<p>The following components of this LLVM release are either untested, known to
1105be broken or unreliable, or are in early development. These components should
1106not be relied on, and bugs should not be filed against them, but they may be
1107useful to some people. In particular, if you would like to work on one of these
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1108components, please contact us on the <a
1109href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]1110
1111<ul>
Chris Lattner1ef5e842010-10-11 05:44:40 +0000[diff] [blame]1112<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, SystemZ
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]1113 and XCore backends are experimental.</li>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]1114<li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets
1115 other than darwin-i386 and darwin-x86_64.</li>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]1116</ul>
1117
1118</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1119
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1120<!-- ======================================================================= -->
1121<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1122 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]1123</div>
1124
1125<div class="doc_text">
1126
1127<ul>
Anton Korobeynikov486c7d32008-06-08 10:24:13 +0000[diff] [blame]1128 <li>The X86 backend does not yet support
1129 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
1130 floating point stack</a>. It supports the 'f' and 't' constraints, but not
1131 'u'.</li>
Duncan Sands0bc15262008-06-08 19:38:43 +0000[diff] [blame]1132 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]1133 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]1134 runtime currently due to lack of support for the 'u' inline assembly
1135 constraint and for X87 floating point inline assembly.</li>
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]1136 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]1137 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]1138 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1139</ul>
1140
1141</div>
1142
1143<!-- ======================================================================= -->
1144<div class="doc_subsection">
1145 <a name="ppc-be">Known problems with the PowerPC back-end</a>
1146</div>
1147
1148<div class="doc_text">
1149
1150<ul>
Nicolas Geoffray77d99502007-05-15 09:21:28 +0000[diff] [blame]1151<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]1152compilation, and lacks support for debug information.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1153</ul>
1154
1155</div>
1156
1157<!-- ======================================================================= -->
1158<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]1159 <a name="arm-be">Known problems with the ARM back-end</a>
1160</div>
1161
1162<div class="doc_text">
1163
1164<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]1165<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands47fc0a22007-09-26 15:59:54 +0000[diff] [blame]1166processors, thumb programs can crash or produce wrong
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]1167results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]1168<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]1169</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]1170</ul>
1171
1172</div>
1173
1174<!-- ======================================================================= -->
1175<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1176 <a name="sparc-be">Known problems with the SPARC back-end</a>
1177</div>
1178
1179<div class="doc_text">
1180
1181<ul>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]1182<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1183 support the 64-bit SPARC ABI (-m64).</li>
1184</ul>
1185
1186</div>
1187
1188<!-- ======================================================================= -->
1189<div class="doc_subsection">
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]1190 <a name="mips-be">Known problems with the MIPS back-end</a>
1191</div>
1192
1193<div class="doc_text">
1194
1195<ul>
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]1196<li>64-bit MIPS targets are not supported yet.</li>
1197</ul>
1198
1199</div>
1200
1201<!-- ======================================================================= -->
1202<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1203 <a name="alpha-be">Known problems with the Alpha back-end</a>
1204</div>
1205
1206<div class="doc_text">
1207
1208<ul>
1209
1210<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
1211appropriate nops inserted to ensure restartability.</li>
1212
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]1213</ul>
1214</div>
1215
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1216<!-- ======================================================================= -->
1217<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]1218 <a name="c-be">Known problems with the C back-end</a>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1219</div>
1220
1221<div class="doc_text">
1222
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]1223<p>The C backend has numerous problems and is not being actively maintained.
1224Depending on it for anything serious is not advised.</p>
1225
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1226<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]1227<li><a href="http://llvm.org/PR802">The C backend has only basic support for
1228 inline assembly code</a>.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000[diff] [blame]1229<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
1230 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif75b2f762009-03-02 12:02:51 +0000[diff] [blame]1231 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandse09506a2008-02-10 13:40:55 +0000[diff] [blame]1232<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands3aa36732009-02-25 11:51:54 +0000[diff] [blame]1233<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1234</ul>
1235
1236</div>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]1237
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1238
1239<!-- ======================================================================= -->
1240<div class="doc_subsection">
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]1241 <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1242</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000[diff] [blame]1243
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1244<div class="doc_text">
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]1245
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]1246<p>llvm-gcc is generally very stable for the C family of languages. The only
1247 major language feature of GCC not supported by llvm-gcc is the
1248 <tt>__builtin_apply</tt> family of builtins. However, some extensions
1249 are only supported on some targets. For example, trampolines are only
1250 supported on some targets (these are used when you take the address of a
1251 nested function).</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1252
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]1253<p>Fortran support generally works, but there are still several unresolved bugs
1254 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
1255 tools/gfortran component for details. Note that llvm-gcc is missing major
1256 Fortran performance work in the frontend and library that went into GCC after
1257 4.2. If you are interested in Fortran, we recommend that you consider using
1258 <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1259
Duncan Sandsd63e1c82010-10-04 10:06:56 +0000[diff] [blame]1260<p>The llvm-gcc 4.2 Ada compiler has basic functionality, but is no longer being
1261actively maintained. If you are interested in Ada, we recommend that you
1262consider using <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1263</div>
1264
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1265<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1266<div class="doc_section">
1267 <a name="additionalinfo">Additional Information</a>
1268</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1269<!-- *********************************************************************** -->
1270
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1271<div class="doc_text">
1272
Chris Lattnercb5596d2005-05-16 17:13:10 +0000[diff] [blame]1273<p>A wide variety of additional information is available on the <a
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]1274href="http://llvm.org">LLVM web page</a>, in particular in the <a
1275href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]1276contains versions of the API documentation which is up-to-date with the
1277Subversion version of the source code.
Misha Brukman96158092005-03-30 19:14:24 +0000[diff] [blame]1278You can access versions of these documents specific to this release by going
1279into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1280
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1281<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]1282us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]1283lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1284
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1285</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1286
1287<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1288
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1289<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1290<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000[diff] [blame]1291 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]1292 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1293 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]1294 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1295
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]1296 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1297 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1298</address>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1299
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1300</body>
1301</html>