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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 7714c91533b5039216f7330555bd45febd7d8fd0 / . / docs / ReleaseNotes.html
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Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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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
Daniel Dunbar13739432008-10-14 23:25:09 +0000[diff] [blame]122<ul>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]123<li>Surely these guys have done something</li>
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]124<li>X86-64 abi improvements? Did they make it in?</li>
Bill Wendling6bc15282009-03-02 04:28:18 +0000[diff] [blame]125</ul>
Chris Lattnerfb97b2d2008-10-13 18:11:54 +0000[diff] [blame]126</div>
127
128<!--=========================================================================-->
129<div class="doc_subsection">
130<a name="clangsa">Clang Static Analyzer</a>
131</div>
132
133<div class="doc_text">
134
Chris Lattner8cdd7932010-04-22 06:38:11 +0000[diff] [blame]135<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a>
136 project is an effort to use static source code analysis techniques to
137 automatically find bugs in C and Objective-C programs (and hopefully <a
138 href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the
139 future</a>!). The tool is very good at finding bugs that occur on specific
140 paths through code, such as on error conditions.</p>
Chris Lattnercc042612008-10-14 00:52:49 +0000[diff] [blame]141
Chris Lattner2e38c7f2010-09-30 00:34:43 +0000[diff] [blame]142<p>The LLVM 2.8 release fixes a number of bugs and slightly improves precision
143 over 2.7, but there are no major new features in the release.
Chris Lattner8cdd7932010-04-22 06:38:11 +0000[diff] [blame]144</p>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]145
146</div>
147
Chris Lattner96a445e2008-10-13 18:01:01 +0000[diff] [blame]148<!--=========================================================================-->
149<div class="doc_subsection">
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]150<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]151</div>
152
153<div class="doc_text">
154<p>
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]155<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]156gcc-4.5. Unlike llvm-gcc, dragonegg in theory does not require any gcc-4.5
157modifications whatsoever (currently one small patch is needed) thanks to the
158new <a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>.
159DragonEgg is a gcc plugin that makes gcc-4.5 use the LLVM optimizers and code
160generators instead of gcc's, just like with llvm-gcc.
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]161</p>
162
163<p>
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000[diff] [blame]164DragonEgg is still a work in progress, but it is able to compile a lot of code,
165for example all of gcc, LLVM and clang. Currently Ada, C, C++ and Fortran work
166well, while all other languages either don't work at all or only work poorly.
167For the moment only the x86-32 and x86-64 targets are supported, and only on
168linux and darwin (darwin may need additional gcc patches).
Duncan Sands749fd832010-04-02 09:23:15 +0000[diff] [blame]169</p>
170
171<p>
Duncan Sands4b1da2b2010-09-30 17:37:34 +0000[diff] [blame]172The 2.8 release has the following notable changes:
173<ul>
174<li>The plugin loads faster due to exporting fewer symbols.</li>
175<li>Additional vector operations such as addps256 are now supported.</li>
176<li>Ada global variables with no initial value are no longer zero initialized,
177resulting in better optimization.</li>
178<li>The '-fplugin-arg-dragonegg-enable-gcc-optzns' flag now runs all gcc
179optimizers, rather than just a handful.</li>
180<li>Fortran programs using common variables now link correctly.</li>
181<li>GNU OMP constructs no longer crash the compiler.</li>
182</ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]183</p>
184
185</div>
186
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]187<!--=========================================================================-->
188<div class="doc_subsection">
189<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
190</div>
191
192<div class="doc_text">
193<p>
194The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
195a Java Virtual Machine (Java VM or JVM) that uses LLVM for static and
196just-in-time compilation. As of LLVM 2.8, VMKit now supports copying garbage
197collectors, and can be configured to use MMTk's copy mark-sweep garbage
198collector. In LLVM 2.8, the VMKit .NET VM is no longer being maintained.
199</p>
200</div>
201
202<!--=========================================================================-->
203<div class="doc_subsection">
204<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
205</div>
206
207<div class="doc_text">
208<p>
209The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
210is a simple library that provides an implementation of the low-level
211target-specific hooks required by code generation and other runtime components.
212For example, when compiling for a 32-bit target, converting a double to a 64-bit
213unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
214function. The compiler-rt library provides highly optimized implementations of
215this and other low-level routines (some are 3x faster than the equivalent
216libgcc routines).</p>
217
218<p>
219All of the code in the compiler-rt project is available under the standard LLVM
220License, a "BSD-style" license. New in LLVM 2.8, compiler_rt now supports
221soft floating point (for targets that don't have a real floating point unit),
222and includes an extensive testsuite for the "blocks" language feature and the
223blocks runtime included in compiler_rt.</p>
224
225</div>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]226
227<!--=========================================================================-->
228<div class="doc_subsection">
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]229<a name="lldb">LLDB: Low Level Debugger</a>
230</div>
231
232<div class="doc_text">
233<p>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]234<a href="http://lldb.llvm.org/">LLDB</a> is a brand new member of the LLVM
235umbrella of projects. LLDB is a next generation, high-performance debugger. It
236is built as a set of reusable components which highly leverage existing
237libraries in the larger LLVM Project, such as the Clang expression parser, the
238LLVM disassembler and the LLVM JIT.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]239
240<p>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]241LLDB is in early development and not included as part of the LLVM 2.8 release,
242but is mature enough to support basic debugging scenarios on Mac OS X in C,
243Objective-C and C++. We'd really like help extending and expanding LLDB to
244support new platforms, new languages, new architectures, and new features.
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]245</p>
246
247</div>
248
249<!--=========================================================================-->
250<div class="doc_subsection">
251<a name="libc++">libc++: C++ Standard Library</a>
252</div>
253
254<div class="doc_text">
255<p>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]256<a href="http://libc++.llvm.org/">libc++</a> is another new member of the LLVM
257family. It is an implementation of the C++ standard library, written from the
258ground up to specifically target the forthcoming C++'0X standard and focus on
259delivering great performance.</p>
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]260
261<p>
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]262As of the LLVM 2.8 release, libc++ is virtually feature complete, but would
263benefit from more testing and better integration with Clang++. It is also
264looking forward to the C++ committee finalizing the C++'0x standard.
Chris Lattnere07043c2010-09-29 05:30:03 +0000[diff] [blame]265</p>
266
267</div>
268
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]269
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]270<!-- *********************************************************************** -->
271<div class="doc_section">
Chris Lattner922d00f2010-07-21 15:57:40 +0000[diff] [blame]272 <a name="externalproj">External Open Source Projects Using LLVM 2.8</a>
Chris Lattnerab68e9e2009-02-26 22:33:38 +0000[diff] [blame]273</div>
274<!-- *********************************************************************** -->
275
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]276<div class="doc_text">
277
278<p>An exciting aspect of LLVM is that it is used as an enabling technology for
279 a lot of other language and tools projects. This section lists some of the
Chris Lattner922d00f2010-07-21 15:57:40 +0000[diff] [blame]280 projects that have already been updated to work with LLVM 2.8.</p>
Chris Lattner7c8e7962010-04-26 17:38:10 +0000[diff] [blame]281</div>
282
Chris Lattner2e38c7f2010-09-30 00:34:43 +0000[diff] [blame]283<!--=========================================================================-->
284<div class="doc_subsection">
285<a name="tce">TTA-based Codesign Environment (TCE)</a>
286</div>
287
288<div class="doc_text">
289<p>
290<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing
291application-specific processors (ASP) based on the Transport triggered
292architecture (TTA). The toolset provides a complete co-design flow from C/C++
293programs down to synthesizable VHDL and parallel program binaries. Processor
294customization points include the register files, function units, supported
295operations, and the interconnection network.</p>
296
297<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target
298independent optimizations and also for parts of code generation. It generates
299new LLVM-based code generators "on the fly" for the designed TTA processors and
300loads them in to the compiler backend as runtime libraries to avoid per-target
301recompilation of larger parts of the compiler chain.</p>
302
303</div>
304
305<!--=========================================================================-->
306<div class="doc_subsection">
307<a name="Horizon">Horizon Bytecode Compiler</a>
308</div>
309
310<div class="doc_text">
311<p>
312<a href="http://www.quokforge.org/projects/horizon">Horizon</a> is a bytecode
313language and compiler written on top of LLVM, intended for producing
314single-address-space managed code operating systems that
315run faster than the equivalent multiple-address-space C systems.
316More in-depth blurb is available on <a
317href="http://www.quokforge.org/projects/horizon/wiki/Wiki">the wiki</a>.</p>
318
319</div>
320
321<!--=========================================================================-->
322<div class="doc_subsection">
323<a name="clamav">Clam AntiVirus</a>
324</div>
325
326<div class="doc_text">
327<p>
328<a href=http://www.clamav.net>Clam AntiVirus</a> is an open source (GPL)
329anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail
330gateways. Since version 0.96 it has <a
331href="http://vrt-sourcefire.blogspot.com/2010/09/introduction-to-clamavs-low-level.html">bytecode
332signatures</a> that allow writing detections for complex malware. It
333uses LLVM's JIT to speed up the execution of bytecode on
334X86,X86-64,PPC32/64, falling back to its own interpreter otherwise.
335The git version was updated to work with LLVM 2.8
336</p>
337
338<p>The <a
339href="http://git.clamav.net/gitweb?p=clamav-bytecode-compiler.git;a=blob_plain;f=docs/user/clambc-user.pdf">
340ClamAV bytecode compiler</a> uses Clang and LLVM to compile a C-like
341language, insert runtime checks, and generate ClamAV bytecode.</p>
342
343</div>
344
345<!--=========================================================================-->
346<div class="doc_subsection">
347<a name="pure">Pure</a>
348</div>
349
350<div class="doc_text">
351<p>
352<a href="http://pure-lang.googlecode.com/">Pure</a>
353is an algebraic/functional
354programming language based on term rewriting. Programs are collections
355of equations which are used to evaluate expressions in a symbolic
356fashion. Pure offers dynamic typing, eager and lazy evaluation, lexical
357closures, a hygienic macro system (also based on term rewriting),
358built-in list and matrix support (including list and matrix
359comprehensions) and an easy-to-use C interface. The interpreter uses
360LLVM as a backend to JIT-compile Pure programs to fast native code.</p>
361
362<p>Pure versions 0.44 and later have been tested and are known to work with
363LLVM 2.8 (and continue to work with older LLVM releases >= 2.5).</p>
364
365</div>
366
367<!--=========================================================================-->
368<div class="doc_subsection">
369<a name="GHC">Glasgow Haskell Compiler (GHC)</a>
370</div>
371
372<div class="doc_text">
373<p>
374<a href="http://www.haskell.org/ghc/">GHC</a> is an open source,
375state-of-the-art programming suite for
376Haskell, a standard lazy functional programming language. It includes
377an optimizing static compiler generating good code for a variety of
378platforms, together with an interactive system for convenient, quick
379development.</p>
380
381<p>In addition to the existing C and native code generators, GHC 7.0 now
382supports an <a
383href="http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/Backends/LLVM">LLVM
384code generator</a>. GHC supports LLVM 2.7 and later.</p>
385
386</div>
387
388<!--=========================================================================-->
389<div class="doc_subsection">
390<a name="Clay">Clay Programming Language</a>
391</div>
392
393<div class="doc_text">
394<p>
Chris Lattner97fe6452010-09-30 01:12:09 +0000[diff] [blame]395<a href="http://tachyon.in/clay/">Clay</a> is a new systems programming
Chris Lattner2e38c7f2010-09-30 00:34:43 +0000[diff] [blame]396language that is specifically designed for generic programming. It makes
397generic programming very concise thanks to whole program type propagation. It
398uses LLVM as its backend.</p>
399
400</div>
Chris Lattner3a1d4cf2010-04-22 21:34:16 +0000[diff] [blame]401
Chris Lattnere0518442010-10-01 06:34:49 +0000[diff] [blame]402<!--=========================================================================-->
403<div class="doc_subsection">
404<a name="llvm-py">llvm-py Python Bindings for LLVM</a>
405</div>
406
407<div class="doc_text">
408<p>
409<a href="http://www.mdevan.org/llvm-py/">llvm-py</a> has been updated to work
410with LLVM 2.8. llvm-py provides Python bindings for LLVM, allowing you to write a
411compiler backend or a VM in Python.</p>
412
413</div>
414
415
Chris Lattner2fb6e5c2010-10-03 23:09:03 +0000[diff] [blame]416<!--=========================================================================-->
417<div class="doc_subsection">
418<a name="FAUST">FAUST Real-Time Audio Signal Processing Language</a>
419</div>
420
421<div class="doc_text">
422<p>
423<a href="http://faust.grame.fr">FAUST</a> is a compiled language for real-time
424audio signal processing. The name FAUST stands for Functional AUdio STream. Its
425programming model combines two approaches: functional programming and block
426diagram composition. In addition with the C, C++, JAVA output formats, the
427Faust compiler can now generate LLVM bitcode, and works with LLVM 2.7 and
4282.8.</p>
429
430</div>
431
432<!--=========================================================================-->
433<div class="doc_subsection">
434<a name="jade">Jade Just-in-time Adaptive Decoder Engine</a>
435</div>
436
437<div class="doc_text">
438<p><a
439href="http://sourceforge.net/apps/trac/orcc/wiki/JadeDocumentation">Jade</a>
440(Just-in-time Adaptive Decoder Engine) is a generic video decoder engine using
441LLVM for just-in-time compilation of video decoder configurations. Those
442configurations are designed by MPEG Reconfigurable Video Coding (RVC) committee.
443MPEG RVC standard is built on a stream-based dataflow representation of
444decoders. It is composed of a standard library of coding tools written in
445RVC-CAL language and a dataflow configuration &emdash; block diagram &emdash;
446of a decoder.</p>
447
448<p>Jade project is hosted as part of the <a href="http://orcc.sf.net">Open
449RVC-CAL Compiler</a> and requires it to translate the RVC-CAL standard library
450of video coding tools into an LLVM assembly code.</p>
451
452</div>
453
454<!--=========================================================================-->
455<div class="doc_subsection">
456<a name="neko_llvm_jit">LLVM JIT for Neko VM</a>
457</div>
458
459<div class="doc_text">
460<p><a href="http://github.com/vava/neko_llvm_jit">Neko LLVM JIT</a>
461replaces the standard Neko JIT with an LLVM-based implementation. While not
462fully complete, it is already providing a 1.5x speedup on 64-bit systems.
463Neko LLVM JIT requires LLVM 2.8 or later.</p>
464
465</div>
466
467<!--=========================================================================-->
468<div class="doc_subsection">
469<a name="crack">Crack Scripting Language</a>
470</div>
471
472<div class="doc_text">
473<p>
474<a href="http://code.google.com/p/crack-language/">Crack</a> aims to provide
475the ease of development of a scripting language with the performance of a
476compiled language. The language derives concepts from C++, Java and Python,
477incorporating object-oriented programming, operator overloading and strong
478typing. Crack 0.2 works with LLVM 2.7, and the forthcoming Crack 0.2.1 release
479builds on LLVM 2.8.</p>
480
481</div>
482
483<!--=========================================================================-->
484<div class="doc_subsection">
485<a name="DresdenTM">Dresden TM Compiler (DTMC)</a>
486</div>
487
488<div class="doc_text">
489<p>
490<a href="http://tm.inf.tu-dresden.de">DTMC</a> provides support for
491Transactional Memory, which is an easy-to-use and efficient way to synchronize
492accesses to shared memory. Transactions can contain normal C/C++ code (e.g.,
493__transaction { list.remove(x); x.refCount--; }) and will be executed
494virtually atomically and isolated from other transactions.</p>
495
496</div>
497
498<!--=========================================================================-->
499<div class="doc_subsection">
500<a name="Kai">Kai Interpreter</a>
501</div>
502
503<div class="doc_text">
504<p>
505<a href="http://www.oriontransfer.co.nz/research/kai">Kai</a> (Japanese 会 for
506meeting/gathering) is an experimental interpreter that provides a highly
507extensible runtime environment and explicit control over the compilation
508process. Programs are defined using nested symbolic expressions, which are all
509parsed into first-class values with minimal intrinsic semantics. Kai can
510generate optimised code at run-time (using LLVM) in order to exploit the nature
511of the underlying hardware and to integrate with external software libraries.
512It is a unique exploration into world of dynamic code compilation, and the
513interaction between high level and low level semantics.</p>
514
515</div>
516
Chris Lattner75547712010-10-03 23:49:06 +0000[diff] [blame]517<!--=========================================================================-->
518<div class="doc_subsection">
519<a name="OSL">OSL: Open Shading Language</a>
520</div>
521
522<div class="doc_text">
523<p>
524<a href="http://code.google.com/p/openshadinglanguage/">OSL</a> is a shading
525language designed for use in physically based renderers and in particular
526production rendering. By using LLVM instead of the interpreter, it was able to
527meet its performance goals (&gt;= C-code) while retaining the benefits of
528runtime specialization and a portable high-level language.
529</p>
530
531</div>
532
533
Chris Lattnere0518442010-10-01 06:34:49 +0000[diff] [blame]534
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]535<!-- *********************************************************************** -->
536<div class="doc_section">
Chris Lattner922d00f2010-07-21 15:57:40 +0000[diff] [blame]537 <a name="whatsnew">What's New in LLVM 2.8?</a>
Chris Lattner8348b472008-06-08 21:58:17 +0000[diff] [blame]538</div>
539<!-- *********************************************************************** -->
540
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]541<div class="doc_text">
542
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]543<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]544minor improvements. Some of the major improvements and new features are listed
545in this section.
Chris Lattnerf8e0b4e2008-06-08 22:59:35 +0000[diff] [blame]546</p>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]547
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]548</div>
549
550<!--=========================================================================-->
551<div class="doc_subsection">
Chris Lattner252b83d2008-02-06 18:00:06 +0000[diff] [blame]552<a name="majorfeatures">Major New Features</a>
553</div>
554
555<div class="doc_text">
556
Chris Lattner922d00f2010-07-21 15:57:40 +0000[diff] [blame]557<p>LLVM 2.8 includes several major new capabilities:</p>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]558
559<ul>
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]560<li>As mentioned above, <a href="#libc++">libc++</a> and <a
561 href="#lldb">LLDB</a> are major new additions to the LLVM collective.</li>
562<li>LLVM 2.8 now has pretty decent support for debugging optimized code. You
563 should be able to reliably get debug info for function arguments, assuming
564 that the value is actually available where you have stopped.</li>
565</ul>
566<li>A new 'llvm-diff' tool is available that does a semantic diff of .ll
567 files.</li>
568<li>The <a href="#mc">MC subproject</a> has made major progress in this release.
569 Direct .o file writing support for darwin/x86[-64] is now reliable and
570 support for other targets and object file formats are in progress.</li>
Chris Lattner8170c102008-02-10 08:18:42 +0000[diff] [blame]571</ul>
Chris Lattnerdc910082010-03-17 06:41:58 +0000[diff] [blame]572
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]573</div>
574
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]575<!--=========================================================================-->
576<div class="doc_subsection">
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]577<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]578</div>
579
580<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]581<p>LLVM IR has several new features for better support of new targets and that
582expose new optimization opportunities:</p>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]583
Chris Lattner791f77b2008-06-05 06:25:56 +0000[diff] [blame]584<ul>
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]585<li>The <a href="LangRef.html#int_libc">memcpy, memmove, and memset</a>
586 intrinsics now take address space qualified pointers and a bit to indicate
587 whether the transfer is "<a href="LangRef.html#volatile">volatile</a>" or not.
588</li>
589<li>Per-instruction debug info metadata is much faster and uses less memory by
590 using the new DebugLoc class.</li>
591<li>LLVM IR now has a more formalized concept of "<a
592 href="LangRef.html#trapvalues">trap values</a>", which allow the optimizer
593 to optimize more aggressively in the presence of undefined behavior, while
594 still producing predictable results.</li>
595<li>LLVM IR now supports two new <a href="LangRef.html#linkage">linkage
596 types</a> (linker_private_weak and linker_private_weak_def_auto) which map
597 onto some obscure MachO concepts.</li>
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]598</ul>
Mikhail Glushenkovea65d7d2008-10-13 02:08:34 +0000[diff] [blame]599
Chris Lattnerf304ffc2008-02-10 08:17:19 +0000[diff] [blame]600</div>
601
602<!--=========================================================================-->
603<div class="doc_subsection">
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]604<a name="optimizer">Optimizer Improvements</a>
605</div>
606
607<div class="doc_text">
608
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]609<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]610release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]611
612<ul>
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]613<li>As mentioned above, the optimizer now has support for updating debug
614 information as it goes. A key aspect of this is the new <a
615 href="SourceLevelDebugging.html#format_common_value">llvm.dbg.value</a>
616 intrinsic. This intrinsic represents debug info for variables that are
617 promoted to SSA values (typically by mem2reg or the -scalarrepl passes).</li>
Chris Lattneracce85d2008-02-10 07:46:44 +0000[diff] [blame]618
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]619<li>The JumpThreading pass is now much more aggressive about implied value
620 relations, allowing it to thread conditions like "a == 4" when a is known to
621 be 13 in one of the predecessors of a block. It does this in conjunction
622 with the new LazyValueInfo analysis pass.</li>
623<li>The new RegionInfo analysis pass identifies single-entry single-exit regions
624 in the CFG. You can play with it with the "opt -regions analyze" or
625 "opt -view-regions" commands.</li>
626<li>The loop optimizer has significantly improve strength reduction and analysis
627 capabilities. Notably it is able to build on the trap value and signed
628 integer overflow information to optimize &lt;= and &gt;= loops.</li>
629<li>The CallGraphSCCPassManager now has some basic support for iterating within
630 an SCC when a optimizer devirtualizes a function call. This allows inlining
631 through indirect call sites that are devirtualized by store-load forwarding
632 and other optimizations.</li>
633<li>The new <A href="Passes.html#loweratomic">-loweratomic</a> pass is available
634 to lower atomic instructions into their non-atomic form. This can be useful
635 to optimize generic code that expects to run in a single-threaded
636 environment.</li>
637</ul>
638
639<!--
640<p>In addition to these features that are done in 2.8, there is preliminary
641 support in the release for Type Based Alias Analysis
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]642 Preliminary work on TBAA but not usable in 2.8.
643 New CorrelatedValuePropagation pass, not on by default in 2.8 yet.
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]644-->
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]645
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]646</div>
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]647
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]648<!--=========================================================================-->
649<div class="doc_subsection">
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]650<a name="mc">MC Level Improvements</a>
651</div>
652
653<div class="doc_text">
654<p>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]655The LLVM Machine Code (aka MC) subsystem was created to solve a number
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]656of problems in the realm of assembly, disassembly, object file format handling,
657and a number of other related areas that CPU instruction-set level tools work
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]658in.</p>
659
660<p>The MC subproject has made great leaps in LLVM 2.8. For example, support for
661 directly writing .o files from LLC (and clang) now works reliably for
662 darwin/x86[-64] (including inline assembly support) and the integrated
663 assembler is turned on by default in Clang for these targets. This provides
664 improved compile times among other things.</p>
665
666<ul>
667<li>The entire compiler has converted over to using the MCStreamer assembler API
668 instead of writing out a .s file textually.</li>
669<li>The "assembler parser" is far more mature than in 2.7, supporting a full
670 complement of directives, now supports assembler macros, etc.</li>
671<li>The "assembler backend" has been completed, including support for relaxation
672 relocation processing and all the other things that an assembler does.</li>
673<li>The MachO file format support is now fully functional and works.</li>
674<li>The MC disassembler now fully supports ARM and Thumb. ARM assembler support
675 is still in early development though.</li>
676<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]677<li>Work on ELF and COFF object files and ARM target support is well underway,
678 but isn't useful yet in LLVM 2.8. Please contact the llvmdev mailing list
679 if you're interested in this.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]680</ul>
681
682<p>For more information, please see the <a
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]683href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
684LLVM MC Project Blog Post</a>.
685</p>
686
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]687</div>
688
689
Chris Lattner4ba2b652010-09-30 16:31:33 +0000[diff] [blame]690<!--=========================================================================-->
691<div class="doc_subsection">
Chris Lattner511433e2009-03-02 03:24:11 +0000[diff] [blame]692<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]693</div>
694
695<div class="doc_text">
696
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]697<p>We have put a significant amount of work into the code generator
698infrastructure, which allows us to implement more aggressive algorithms and make
699it run faster:</p>
Chris Lattner0b832202008-06-08 02:45:07 +0000[diff] [blame]700
701<ul>
Chris Lattner3bdcda12010-10-04 03:58:12 +0000[diff] [blame]702<li>The clang/gcc -momit-leaf-frame-pointer argument is now supported.</li>
703<li>The clang/gcc -ffunction-sections and -fdata-sections arguments are now
704 supported on ELF targets (like GCC).</li>
705<li>The MachineCSE pass is now tuned and on by default. It eliminates common
706 subexpressions that are exposed when lowering to machine instructions.</li>
707<li>The "local" register allocator was replaced by a new "fast" register
708 allocator. This new allocator (which is often used at -O0) is substantially
709 faster and produces better code than the old local register allocator.</li>
710<li>A new LLC "-regalloc=default" option is available, which automatically
711 chooses a register allocator based on the -O optimization level.</li>
712<li>The common code generator code was modified to promote illegal argument and
713 return value vectors to wider ones when possible instead of scalarizing
714 them. For example, &lt;3 x float&gt; will now pass in one SSE register
715 instead of 3 on X86. This generates substantially better code since the
716 rest of the code generator was already expecting this.</li>
717<li>The code generator uses a new "COPY" machine instruction. This speeds up
718 the code generator and eliminates the need for targets to implement the
719 isMoveInstr hook. Also, the copyRegToReg hook was renamed to copyPhysReg
720 and simplified.</li>
721<li>The code generator now has a "LocalStackSlotPass", which optimizes stack
722 slot access for targets (like ARM) that have limited stack displacement
723 addressing.</li>
724<li>A new "PeepholeOptimizer" is available, which eliminates sign and zero
725 extends, and optimizes away compare instructions when the condition result
726 is available from a previous instruction.</li>
727<li>Atomic operations now get legalized into simpler atomic operations if not
728 natively supported, easy the implementation burden on targets.</li>
729<li>The bottom-up pre-allocation scheduler is now register pressure aware,
730 allowing it to avoid overscheduling in high pressure situations while still
731 aggressively scheduling when registers are available.</li>
732<li>A new instruction-level-parallelism pre-allocation scheduler is available,
733 which is also register pressure aware. This scheduler has shown substantial
734 wins on X86-64 and is on by default.</li>
735<li>The tblgen type inference algorithm was rewritten to be more consistent and
736 diagnose more target bugs. If you have an out-of-tree backend, you may
737 find that it finds bugs in your target description. This support also
738 allows limited support for writing patterns for instructions that return
739 multiple results (e.g. a virtual register and a flag result). The
740 'parallel' modifier in tblgen was removed, you should use the new support
741 for multiple results instead.</li>
742<li>A new (experimental) "-rendermf" pass is available which renders a
743 MachineFunction into HTML, showing live ranges and other useful
744 details.</li>
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame^]745<li>The new SubRegIndex tablegen class allows subregisters to be indexed
746 symbolically instead of numerically. If your target uses subregisters you
747 will need to adapt to use SubRegIndex when you upgrade to 2.8.</li>
Chris Lattner3bdcda12010-10-04 03:58:12 +0000[diff] [blame]748<!-- SplitKit -->
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]749
Chris Lattner3bdcda12010-10-04 03:58:12 +0000[diff] [blame]750<li>The -fast-isel instruction selection path (used at -O0 on X86) was rewritten
751 to work bottom-up on basic blocks instead of top down. This makes it
752 slightly faster (because the MachineDCE pass is not needed any longer) and
753 allows it to generate better code in some cases.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]754
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]755</ul>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]756</div>
757
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]758<!--=========================================================================-->
759<div class="doc_subsection">
760<a name="x86">X86-32 and X86-64 Target Improvements</a>
761</div>
762
763<div class="doc_text">
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame^]764<p>New features and major changes in the X86 target include:
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]765</p>
766
767<ul>
Chris Lattner922d00f2010-07-21 15:57:40 +0000[diff] [blame]768<li>The X86 backend now supports holding X87 floating point stack values
769 in registers across basic blocks, dramatically improving performance of code
770 that uses long double, and when targetting CPUs that don't support SSE.</li>
Chris Lattner511433e2009-03-02 03:24:11 +0000[diff] [blame]771
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame^]772<li>The X86 backend now uses a SSEDomainFix pass to optimize SSE operations. On
773 Nehalem ("Core i7") and newer CPUs there is a 2 cycle latency penalty on
774 using a register in a different domain than where it was defined. This pass
775 optimizes away these stalls.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]776
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame^]777<li>The X86 backend now promote 16-bit integer operations to 32-bits when
778 possible. This avoids 0x66 prefixes, which are slow on some
779 microarchitectures and bloat the code on all of them.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]780
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame^]781<li>The X86 backend now supports the Microsoft "thiscall" calling convention,
782 and a <a href="LangRef.html#callingconv">calling convention</a> to support
783 <a href="#GHC">ghc</a>.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]784
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame^]785<li>The X86 backend supports a new "llvm.x86.int" intrinsic, which maps onto
786 the X86 "int $42" and "int3" instructions.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]787
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame^]788<li>At the IR level, the &lt;2 x float&gt; datatype is now promoted and passed
789 around as a &lt;4 x float&gt; instead of being passed and returns as an MMX
790 vector. If you have a frontend that uses this, please pass and return a
791 &lt;2 x i32&gt; instead (using bitcasts).</li>
792
793<li>When printing .s files in verbose assembly mode (the default for clang -S),
794 the X86 backend now decodes X86 shuffle instructions and prints human
795 readable comments after the most inscrutible of them, e.g.:
796
797<pre>
798 insertps $113, %xmm3, %xmm0 <i># xmm0 = zero,xmm0[1,2],xmm3[1]</i>
799 unpcklps %xmm1, %xmm0 <i># xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1]</i>
800 pshufd $1, %xmm1, %xmm1 <i># xmm1 = xmm1[1,0,0,0]</i>
801</pre>
802</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]803
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]804</ul>
805
Chris Lattner917cc712009-03-02 02:37:32 +0000[diff] [blame]806</div>
Chris Lattner84977642007-09-21 03:54:09 +0000[diff] [blame]807
808<!--=========================================================================-->
809<div class="doc_subsection">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]810<a name="ARM">ARM Target Improvements</a>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]811</div>
812
813<div class="doc_text">
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]814<p>New features of the ARM target include:
815</p>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]816
817<ul>
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame^]818<li>The ARM backend now optimizes tail calls into jumps.</li>
819<li>Scheduling is improved through the new list-hybrid scheduler as well
820 as through better modeling of structural hazards.</li>
821<li><a href="LangRef.html#int_fp16">Half float</a> instructions are now
822 supported.</li>
823<li>NEON support has been improved to model instructions which operate onto
824 multiple consequtive registers more aggressively. This avoids lots of
825 extraneous register copies.</li>
826<li>The ARM backend now uses a new "ARMGlobalMerge" pass, which merges several
827 global variables into one, saving extra address computation (all the global
828 variables can be accessed via same base address) and potentially reducing
829 register pressure.</li>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]830
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame^]831<li>The ARM has received many minor improvements and tweaks which lead to
832substantially better performance in a wide range of different scenarios.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]833
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]834<li>The ARM NEON intrinsics have been substantially reworked to reduce
835 redundancy and improve code generation. Some of the major changes are:
836 <ol>
837 <li>
838 All of the NEON load and store intrinsics (llvm.arm.neon.vld* and
839 llvm.arm.neon.vst*) take an extra parameter to specify the alignment in bytes
840 of the memory being accessed.
841 </li>
842 <li>
843 The llvm.arm.neon.vaba intrinsic (vector absolute difference and
844 accumulate) has been removed. This operation is now represented using
845 the llvm.arm.neon.vabd intrinsic (vector absolute difference) followed by a
846 vector add.
847 </li>
848 <li>
849 The llvm.arm.neon.vabdl and llvm.arm.neon.vabal intrinsics (lengthening
850 vector absolute difference with and without accumlation) have been removed.
851 They are represented using the llvm.arm.neon.vabd intrinsic (vector absolute
852 difference) followed by a vector zero-extend operation, and for vabal,
853 a vector add.
854 </li>
855 <li>
856 The llvm.arm.neon.vmovn intrinsic has been removed. Calls of this intrinsic
857 are now replaced by vector truncate operations.
858 </li>
859 <li>
860 The llvm.arm.neon.vmovls and llvm.arm.neon.vmovlu intrinsics have been
861 removed. They are now represented as vector sign-extend (vmovls) and
862 zero-extend (vmovlu) operations.
863 </li>
864 <li>
865 The llvm.arm.neon.vaddl*, llvm.arm.neon.vaddw*, llvm.arm.neon.vsubl*, and
866 llvm.arm.neon.vsubw* intrinsics (lengthening vector add and subtract) have
867 been removed. They are replaced by vector add and vector subtract operations
868 where one (vaddw, vsubw) or both (vaddl, vsubl) of the operands are either
869 sign-extended or zero-extended.
870 </li>
871 <li>
872 The llvm.arm.neon.vmulls, llvm.arm.neon.vmullu, llvm.arm.neon.vmlal*, and
873 llvm.arm.neon.vmlsl* intrinsics (lengthening vector multiply with and without
874 accumulation and subtraction) have been removed. These operations are now
875 represented as vector multiplications where the operands are either
876 sign-extended or zero-extended, followed by a vector add for vmlal or a
877 vector subtract for vmlsl. Note that the polynomial vector multiply
878 intrinsic, llvm.arm.neon.vmullp, remains unchanged.
879 </li>
880 </ol>
Bob Wilson5b2fb952010-09-13 17:37:55 +0000[diff] [blame]881</li>
Chris Lattner7714c912010-10-04 04:39:25 +0000[diff] [blame^]882
Bob Wilsone8472772010-09-13 17:39:35 +0000[diff] [blame]883</ul>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]884</div>
Chris Lattnerc441fb82009-03-01 02:30:21 +0000[diff] [blame]885
Chris Lattner77d29b12008-06-05 08:02:49 +0000[diff] [blame]886
887<!--=========================================================================-->
888<div class="doc_subsection">
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]889<a name="changes">Major Changes and Removed Features</a>
890</div>
891
892<div class="doc_text">
893
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]894<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]895on LLVM 2.7, this section lists some "gotchas" that you may run into upgrading
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]896from the previous release.</p>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]897
898<ul>
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]899<li>The build configuration machinery changed the output directory names. It
900 wasn't clear to many people that "Release-Asserts" build was a release build
901 without asserts. To make this more clear, "Release" does not include
902 assertions and "Release+Asserts" does (likewise, "Debug" and
903 "Debug+Asserts").</li>
904<li>The MSIL Backend was removed, it was unsupported and broken.</li>
905<li>The ABCD, SSI, and SCCVN passes were removed. These were not fully
906 functional and their behavior has been or will be subsumed by the
907 LazyValueInfo pass.</li>
908<li>The LLVM IR 'Union' feature was removed. While this is a desirable feature
909 for LLVM IR to support, the existing implementation was half baked and
910 barely useful. We'd really like anyone interested to resurrect the work and
911 finish it for a future release.</li>
912<li>If you're used to reading .ll files, you'll probably notice that .ll file
913 dumps don't produce #uses comments anymore. To get them, run a .bc file
914 through "llvm-dis --show-annotations".</li>
Chris Lattner11b66112010-10-04 02:42:39 +0000[diff] [blame]915<li>Target triples are now stored in a normalized form, and all inputs from
916 humans are expected to be normalized by Triple::normalize before being
917 stored in a module triple or passed to another library.</li>
Chris Lattnerb7c85b42010-04-21 05:17:40 +0000[diff] [blame]918</ul>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]919
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]920
921
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]922<p>In addition, many APIs have changed in this release. Some of the major LLVM
923API changes are:</p>
Chris Lattnereeb4da02008-10-13 22:06:31 +0000[diff] [blame]924<ul>
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]925<li>LLVM 2.8 changes the internal order of operands in <a
926 href="http://llvm.org/doxygen/classllvm_1_1InvokeInst.html"><tt>InvokeInst</tt></a>
927 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]928 To be portable across releases, please use the <tt>CallSite</tt> class and the
929 high-level accessors, such as <tt>getCalledValue</tt> and
930 <tt>setUnwindDest</tt>.
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]931</li>
932<li>
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]933 You can no longer pass use_iterators directly to cast&lt;&gt; (and similar),
934 because these routines tend to perform costly dereference operations more
935 than once. You have to dereference the iterators yourself and pass them in.
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]936</li>
937<li>
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]938 llvm.memcpy.*, llvm.memset.*, llvm.memmove.* intrinsics take an extra
939 parameter now ("i1 isVolatile"), totaling 5 parameters, and the pointer
940 operands are now address-space qualified.
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]941 If you were creating these intrinsic calls and prototypes yourself (as opposed
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]942 to using Intrinsic::getDeclaration), you can use
943 UpgradeIntrinsicFunction/UpgradeIntrinsicCall to be portable accross releases.
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]944</li>
945<li>
946 SetCurrentDebugLocation takes a DebugLoc now instead of a MDNode.
947 Change your code to use
948 SetCurrentDebugLocation(DebugLoc::getFromDILocation(...)).
949</li>
950<li>
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]951 The <tt>RegisterPass</tt> and <tt>RegisterAnalysisGroup</tt> templates are
952 considered deprecated, but continue to function in LLVM 2.8. Clients are
953 strongly advised to use the upcoming <tt>INITIALIZE_PASS()</tt> and
954 <tt>INITIALIZE_AG_PASS()</tt> macros instead.
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]955</li>
956<li>
957 The constructor for the Triple class no longer tries to understand odd triple
958 specifications. Frontends should ensure that they only pass valid triples to
959 LLVM. The Triple::normalize utility method has been added to help front-ends
960 deal with funky triples.
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]961</li>
962
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]963<li>
964 Some APIs got renamed:
965 <ul>
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]966 <li>llvm_report_error -&gt; report_fatal_error</li>
967 <li>llvm_install_error_handler -&gt; install_fatal_error_handler</li>
968 <li>llvm::DwarfExceptionHandling -&gt; llvm::JITExceptionHandling</li>
969 <li>VISIBILITY_HIDDEN -&gt; LLVM_LIBRARY_VISIBILITY</li>
Chris Lattner4eac9242010-10-02 22:44:15 +0000[diff] [blame]970 </ul>
971</li>
972
Devang Patelb34dd132008-10-14 20:03:43 +0000[diff] [blame]973</ul>
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]974
Chris Lattnerf6662f92008-10-13 17:57:36 +0000[diff] [blame]975</div>
976
977
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]978<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]979<div class="doc_section">
980 <a name="knownproblems">Known Problems</a>
981</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]982<!-- *********************************************************************** -->
983
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]984<div class="doc_text">
985
Mikhail Glushenkovf795ef02009-03-01 18:09:47 +0000[diff] [blame]986<p>This section contains significant known problems with the LLVM system,
Chris Lattnere18b32e2008-11-10 05:40:34 +0000[diff] [blame]987listed by component. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]988href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]989there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]990
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]991</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]992
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]993<!-- ======================================================================= -->
994<div class="doc_subsection">
995 <a name="experimental">Experimental features included with this release</a>
996</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]997
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]998<div class="doc_text">
999
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]1000<p>The following components of this LLVM release are either untested, known to
1001be broken or unreliable, or are in early development. These components should
1002not be relied on, and bugs should not be filed against them, but they may be
1003useful 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]1004components, please contact us on the <a
1005href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]1006
1007<ul>
Chris Lattnerbb117712010-10-04 01:29:06 +0000[diff] [blame]1008<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, PIC16, SystemZ
1009 and XCore backends are experimental.</li>
Chris Lattner7d9b6b42010-10-02 21:59:30 +0000[diff] [blame]1010<li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets
1011 other than darwin-i386 and darwin-x86_64.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]1012</ul>
1013
1014</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1015
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1016<!-- ======================================================================= -->
1017<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1018 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]1019</div>
1020
1021<div class="doc_text">
1022
1023<ul>
Anton Korobeynikova6094be2008-06-08 10:24:13 +0000[diff] [blame]1024 <li>The X86 backend does not yet support
1025 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
1026 floating point stack</a>. It supports the 'f' and 't' constraints, but not
1027 'u'.</li>
Duncan Sands47eff2b2008-06-08 19:38:43 +0000[diff] [blame]1028 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]1029 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]1030 runtime currently due to lack of support for the 'u' inline assembly
1031 constraint and for X87 floating point inline assembly.</li>
Dan Gohman8207ba92008-06-08 23:05:11 +0000[diff] [blame]1032 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner914ce462010-04-22 06:28:20 +0000[diff] [blame]1033 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman8207ba92008-06-08 23:05:11 +0000[diff] [blame]1034 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1035</ul>
1036
1037</div>
1038
1039<!-- ======================================================================= -->
1040<div class="doc_subsection">
1041 <a name="ppc-be">Known problems with the PowerPC back-end</a>
1042</div>
1043
1044<div class="doc_text">
1045
1046<ul>
Nicolas Geoffraye4285dc2007-05-15 09:21:28 +0000[diff] [blame]1047<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]1048compilation, and lacks support for debug information.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1049</ul>
1050
1051</div>
1052
1053<!-- ======================================================================= -->
1054<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]1055 <a name="arm-be">Known problems with the ARM back-end</a>
1056</div>
1057
1058<div class="doc_text">
1059
1060<ul>
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]1061<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sandsc90d68b2007-09-26 15:59:54 +0000[diff] [blame]1062processors, thumb programs can crash or produce wrong
Chris Lattner57a460e2007-05-23 04:39:32 +0000[diff] [blame]1063results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]1064<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]1065</li>
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]1066</ul>
1067
1068</div>
1069
1070<!-- ======================================================================= -->
1071<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1072 <a name="sparc-be">Known problems with the SPARC back-end</a>
1073</div>
1074
1075<div class="doc_text">
1076
1077<ul>
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]1078<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]1079 support the 64-bit SPARC ABI (-m64).</li>
1080</ul>
1081
1082</div>
1083
1084<!-- ======================================================================= -->
1085<div class="doc_subsection">
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000[diff] [blame]1086 <a name="mips-be">Known problems with the MIPS back-end</a>
1087</div>
1088
1089<div class="doc_text">
1090
1091<ul>
Bruno Cardoso Lopesb7e1a4f2008-10-25 14:56:26 +0000[diff] [blame]1092<li>64-bit MIPS targets are not supported yet.</li>
1093</ul>
1094
1095</div>
1096
1097<!-- ======================================================================= -->
1098<div class="doc_subsection">
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1099 <a name="alpha-be">Known problems with the Alpha back-end</a>
1100</div>
1101
1102<div class="doc_text">
1103
1104<ul>
1105
1106<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
1107appropriate nops inserted to ensure restartability.</li>
1108
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]1109</ul>
1110</div>
1111
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1112<!-- ======================================================================= -->
1113<div class="doc_subsection">
Chris Lattnerf3e5bc62007-05-14 06:56:09 +0000[diff] [blame]1114 <a name="c-be">Known problems with the C back-end</a>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1115</div>
1116
1117<div class="doc_text">
1118
Chris Lattner3016ee92010-09-29 05:34:42 +0000[diff] [blame]1119<p>The C backend has numerous problems and is not being actively maintained.
1120Depending on it for anything serious is not advised.</p>
1121
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1122<ul>
Chris Lattner5733b272008-06-05 06:35:40 +0000[diff] [blame]1123<li><a href="http://llvm.org/PR802">The C backend has only basic support for
1124 inline assembly code</a>.</li>
Chris Lattner725a0d82007-09-26 06:01:35 +0000[diff] [blame]1125<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
1126 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif4906abe2009-03-02 12:02:51 +0000[diff] [blame]1127 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandsf74c0cc2008-02-10 13:40:55 +0000[diff] [blame]1128<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands50723a92009-02-25 11:51:54 +0000[diff] [blame]1129<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattner26299222006-11-18 07:51:14 +0000[diff] [blame]1130</ul>
1131
1132</div>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]1133
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1134
1135<!-- ======================================================================= -->
1136<div class="doc_subsection">
Chris Lattner3016ee92010-09-29 05:34:42 +0000[diff] [blame]1137 <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1138</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]1139
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1140<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]1141
Chris Lattner3016ee92010-09-29 05:34:42 +0000[diff] [blame]1142<p>llvm-gcc is generally very stable for the C family of languages. The only
1143 major language feature of GCC not supported by llvm-gcc is the
1144 <tt>__builtin_apply</tt> family of builtins. However, some extensions
1145 are only supported on some targets. For example, trampolines are only
1146 supported on some targets (these are used when you take the address of a
1147 nested function).</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1148
Chris Lattner3016ee92010-09-29 05:34:42 +0000[diff] [blame]1149<p>Fortran support generally works, but there are still several unresolved bugs
1150 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
1151 tools/gfortran component for details. Note that llvm-gcc is missing major
1152 Fortran performance work in the frontend and library that went into GCC after
1153 4.2. If you are interested in Fortran, we recommend that you consider using
1154 <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1155
Chris Lattner3016ee92010-09-29 05:34:42 +0000[diff] [blame]1156<p>The llvm-gcc 4.2 Ada compiler has basic functionality. However, this is not a
1157mature technology, and problems should be expected. For example:</p>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1158<ul>
Duncan Sands27aff872008-06-08 20:18:35 +0000[diff] [blame]1159<li>The Ada front-end currently only builds on X86-32. This is mainly due
John Criswell524a5dd2009-03-02 15:28:15 +0000[diff] [blame]1160to lack of trampoline support (pointers to nested functions) on other platforms.
1161However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1162which does support trampolines.</li>
1163<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
Duncan Sands326a4982009-02-25 11:59:06 +0000[diff] [blame]1164This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
1165exception handling, which is used internally by the compiler.
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]1166Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
Duncan Sands978bcee2008-10-13 17:27:23 +0000[diff] [blame]1167<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
1168and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sands326a4982009-02-25 11:59:06 +0000[diff] [blame]1169(c380004 also fails with gcc-4.2 mainline).
1170If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
1171causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sandsdd3e6722009-03-02 16:35:57 +0000[diff] [blame]1172<li>Some GCC specific Ada tests continue to crash the compiler.</li>
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]1173<li>The <tt>-E</tt> binder option (exception backtraces)
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1174<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
Chris Lattner61358ab2009-10-13 17:48:04 +0000[diff] [blame]1175crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1176<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
1177or finish at a non-byte offset</a> in a record. Workaround: do not pack records
1178or use representation clauses that result in a field of a non-discrete type
1179starting or finishing in the middle of a byte.</li>
Chris Lattnere6e1b352008-06-08 21:19:07 +0000[diff] [blame]1180<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
1181'main' as generated by the Ada binder to be invalid</a>.
1182Workaround: hand edit the file to use pointers for <tt>argv</tt> and
1183<tt>envp</tt> rather than integers.</li>
1184<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
1185ignored</a>.</li>
Chris Lattner2b659ef2008-02-12 06:29:45 +0000[diff] [blame]1186</ul>
1187</div>
1188
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1189<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1190<div class="doc_section">
1191 <a name="additionalinfo">Additional Information</a>
1192</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1193<!-- *********************************************************************** -->
1194
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1195<div class="doc_text">
1196
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]1197<p>A wide variety of additional information is available on the <a
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]1198href="http://llvm.org">LLVM web page</a>, in particular in the <a
1199href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer669ed452007-07-09 08:04:31 +0000[diff] [blame]1200contains versions of the API documentation which is up-to-date with the
1201Subversion version of the source code.
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]1202You can access versions of these documents specific to this release by going
1203into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1204
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1205<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]1206us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]1207lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1208
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1209</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1210
1211<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]1212
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1213<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]1214<address>
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Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]1219
Chris Lattnerb4b0ce72007-05-18 00:44:29 +0000[diff] [blame]1220 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
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Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]1222</address>
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