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gerrit-public.fairphone.software / toolchain / llvm-project / 87adbe4836112c3e5f20194e2c1478b5c15fd922 / . / llvm / docs / ReleaseNotes.html
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Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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4<head>
Reid Spencere4190fa2004-11-18 18:38:58 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]6 <link rel="stylesheet" href="llvm.css" type="text/css">
Chris Lattner7fad44b2009-02-25 04:41:31 +0000[diff] [blame]7 <title>LLVM 2.5 Release Notes</title>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]8</head>
9<body>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]10
Chris Lattner7fad44b2009-02-25 04:41:31 +0000[diff] [blame]11<div class="doc_title">LLVM 2.5 Release Notes</div>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]12
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]13<ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]14 <li><a href="#intro">Introduction</a></li>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]15 <li><a href="#subproj">Sub-project Status Update</a></li>
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]16 <li><a href="#externalproj">External Projects Using LLVM 2.5</a></li>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]17 <li><a href="#whatsnew">What's New in LLVM 2.5?</a></li>
Chris Lattner77a51732004-04-30 22:17:12 +0000[diff] [blame]18 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]19 <li><a href="#portability">Portability and Supported Platforms</a></li>
Dan Gohmanad888912008-10-14 16:23:02 +0000[diff] [blame]20 <li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]21 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]22</ol>
23
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]24<div class="doc_author">
Dan Gohmanad888912008-10-14 16:23:02 +0000[diff] [blame]25 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]26</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]27
28<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]29<div class="doc_section">
30 <a name="intro">Introduction</a>
31</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]32<!-- *********************************************************************** -->
33
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]34<div class="doc_text">
35
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]36<p>This document contains the release notes for the LLVM Compiler
Chris Lattner7fad44b2009-02-25 04:41:31 +0000[diff] [blame]37Infrastructure, release 2.5. Here we describe the status of LLVM, including
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]38major improvements from the previous release and significant known problems.
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]39All LLVM releases may be downloaded from the <a
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]40href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]41
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]42<p>For more information about LLVM, including information about the latest
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]43release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattnere7525b52003-10-07 21:38:31 +0000[diff] [blame]44web site</a>. If you have questions or comments, the <a
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]45href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's Mailing
46List</a> is a good place to send them.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]47
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]48<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]49main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greif355f81c2008-10-14 11:00:32 +0000[diff] [blame]50current one. To see the release notes for a specific release, please see the
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]51<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]52
53</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]54
Chris Lattner7fad44b2009-02-25 04:41:31 +0000[diff] [blame]55<!-- Unfinished features in 2.5:
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]56 Machine LICM
57 Machine Sinking
Chris Lattnerd02da042009-02-25 06:34:50 +0000[diff] [blame]58 target-specific intrinsics
59 gold lto plugin
Chris Lattner3ab27b72009-02-25 07:32:53 +0000[diff] [blame]60 pre-alloc splitter, strong phi elim
Chris Lattnerc4d68542008-10-12 19:47:48 +0000[diff] [blame]61 llc -enable-value-prop, propagation of value info (sign/zero ext info) from
62 one MBB to another
Chris Lattnerd02da042009-02-25 06:34:50 +0000[diff] [blame]63 debug info for optimized code
Chris Lattner07bf7e92009-02-26 07:29:17 +0000[diff] [blame]64 interpreter + libffi
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]65 postalloc scheduler: anti dependence breaking, hazard recognizer?
66
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]67initial support for debug line numbers when optimization enabled, not useful in
68 2.5 but will be for 2.6.
69
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]70 -->
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]71
Chris Lattnerc4d68542008-10-12 19:47:48 +0000[diff] [blame]72 <!-- for announcement email:
Chris Lattnerd02da042009-02-25 06:34:50 +0000[diff] [blame]73 -->
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]74
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]75<!-- *********************************************************************** -->
76<div class="doc_section">
77 <a name="subproj">Sub-project Status Update</a>
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]78</div>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]79<!-- *********************************************************************** -->
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]80
81<div class="doc_text">
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]82<p>
Chris Lattner7fad44b2009-02-25 04:41:31 +0000[diff] [blame]83The LLVM 2.5 distribution currently consists of code from the core LLVM
Bill Wendling87adbe42009-03-02 04:28:18 +0000[diff] [blame^]84repository &mdash;which roughly includes the LLVM optimizers, code generators
85and supporting tools &mdash; and the llvm-gcc repository. In addition to this
86code, the LLVM Project includes other sub-projects that are in development. The
87two which are the most actively developed are the <a href="#clang">Clang
88Project</a> and the <a href="#vmkit">VMKit Project</a>.
89</pp>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]90
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]91</div>
92
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]93
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]94<!--=========================================================================-->
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]95<div class="doc_subsection">
Chris Lattner44c09cd2008-10-13 18:11:54 +0000[diff] [blame]96<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]97</div>
98
99<div class="doc_text">
100
101<p>The <a href="http://clang.llvm.org/">Clang project</a> is an effort to build
Bill Wendling87adbe42009-03-02 04:28:18 +0000[diff] [blame^]102a set of new 'LLVM native' front-end technologies for the LLVM optimizer and
103code generator. While Clang is not included in the LLVM 2.5 release, it is
104continuing to make major strides forward in all areas. Its C and Objective-C
Chris Lattnerf70a0242009-02-25 05:09:54 +0000[diff] [blame]105parsing and code generation support is now very solid. For example, it is
Bill Wendling87adbe42009-03-02 04:28:18 +0000[diff] [blame^]106capable of successfully building many real-world applications for X86-32
107andX86-64,
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]108including <a href="http://wiki.freebsd.org/BuildingFreeBSDWithClang">the FreeBSD
Bill Wendling87adbe42009-03-02 04:28:18 +0000[diff] [blame^]109kernel</a>. C++ is also
110making <a href="http://clang.llvm.org/cxx_status.html">incredible progress</a>,
111and work on templates has recently started.</p>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]112
Chris Lattnerf70a0242009-02-25 05:09:54 +0000[diff] [blame]113<p>While Clang is not yet production quality, it is progressing very nicely and
114is quite usable for building many C and Objective-C applications. If you are
115interested in fast compiles and good diagnostics, we encourage you to try it out
Chris Lattnerd02da042009-02-25 06:34:50 +0000[diff] [blame]116by <a href="http://clang.llvm.org/get_started.html">building from mainline</a>
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]117and reporting any issues you hit to the <a
Chris Lattnerf70a0242009-02-25 05:09:54 +0000[diff] [blame]118href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">Clang front-end mailing
119list</a>.</p>
120
121<p>In the LLVM 2.5 time-frame, the Clang team has made many improvements:</p>
Bill Wendlingef362462008-10-27 09:27:33 +0000[diff] [blame]122
Daniel Dunbarc11b40f2008-10-14 23:25:09 +0000[diff] [blame]123<ul>
Chris Lattnerf70a0242009-02-25 05:09:54 +0000[diff] [blame]124<li>Clang now has a new driver, which is focused on providing a GCC-compatible
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]125 interface.</li>
126<li>The X86-64 ABI is now supported.</li>
127<li>Precompiled header support is now implemented.</li>
Chris Lattnerf70a0242009-02-25 05:09:54 +0000[diff] [blame]128<li>Objective-C support is significantly improved beyond LLVM 2.4, supporting
129 many features, such as Objective-C Garbage Collection.</li>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]130<li>Many many bugs are fixed and many features have been added.</li>
Bill Wendling87adbe42009-03-02 04:28:18 +0000[diff] [blame^]131</ul>
Chris Lattner44c09cd2008-10-13 18:11:54 +0000[diff] [blame]132</div>
133
134<!--=========================================================================-->
135<div class="doc_subsection">
136<a name="clangsa">Clang Static Analyzer</a>
137</div>
138
139<div class="doc_text">
140
Ted Kremenekc11fae82009-02-27 07:01:32 +0000[diff] [blame]141<p>Previously announced in the last LLVM release, the Clang project also
142includes an early stage static source code analysis tool for <a
143href="http://clang.llvm.org/StaticAnalysis.html">automatically finding bugs</a>
144in C and Objective-C programs. The tool performs a growing set of checks to find
145bugs that occur on a specific path within a program.</p>
Chris Lattnerbcffa5a2008-10-14 00:52:49 +0000[diff] [blame]146
Ted Kremenekc11fae82009-02-27 07:01:32 +0000[diff] [blame]147<p>In the LLVM 2.5 time-frame there have been many significant improvements to
148the analyzer's core path simulation engine and machinery for generating
149path-based bug reports to end-users. Particularly noteworthy improvements
150include experimental support for full field-sensitivity and reasoning about heap
151objects as well as an improved value-constraints subengine that does a much
152better job of reasoning about inequality relationships (e.g., <tt>x &gt; 2</tt>)
153between variables and constants.
Ted Kremenek3db01842008-10-14 05:14:21 +0000[diff] [blame]154
Ted Kremenekc11fae82009-02-27 07:01:32 +0000[diff] [blame]155<p>The set of checks performed by the static analyzer continue to expand, and
156future plans for the tool include full source-level inter-procedural analysis
157and deeper checks such as buffer overrun detection. There are many opportunities
158to extend and enhance the static analyzer, and anyone interested in working on
159this project is encouraged to get involved!</p>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]160
161</div>
162
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]163<!--=========================================================================-->
164<div class="doc_subsection">
Nicolas Geoffraye5ec9322008-10-14 19:23:04 +0000[diff] [blame]165<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]166</div>
167
168<div class="doc_text">
169<p>
Nicolas Geoffraye5ec9322008-10-14 19:23:04 +0000[diff] [blame]170The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]171a JVM and a CLI Virtual Machines (Microsoft .NET is an
172implementation of the CLI) using the Just-In-Time compiler of LLVM.</p>
173
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]174<p>Following LLVM 2.5, VMKit has its first release that you can find on its
Nicolas Geoffray54efd492008-10-15 20:25:04 +0000[diff] [blame]175<a href="http://vmkit.llvm.org/releases/">webpage</a>. The release includes
176bug fixes, cleanup and new features. The major changes are:</p>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]177
Nicolas Geoffraye5ec9322008-10-14 19:23:04 +0000[diff] [blame]178<ul>
179
Chris Lattnerd38d5e82009-02-26 05:20:36 +0000[diff] [blame]180<li>Ahead of Time compiler: compiles .class files to llvm .bc. VMKit uses this
181functionality to native compile the standard classes (eg java.lang.String).
182Users can compile AOT .class files into dynamic libraries and run them with the
183help of VMKit.</li>
184
185<li>New exception model: the dwarf exception model is very slow for
186exception-intensive applications, so the JVM has had a new implementation of
187exceptions which check at each function call if an exception happened. There is
188a low performance penalty on applications without exceptions, but it is a big
189gain for exception-intensive applications. For example the jack benchmark in
190Spec JVM98 is 6x faster (performance gain of 83%).</li>
191
192<li>New support for OSX/X64, Linux/X64 (with the Boehm GC), Linux/ppc32.</li>
Nicolas Geoffraye5ec9322008-10-14 19:23:04 +0000[diff] [blame]193
194</ul>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]195</div>
196
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]197<!-- *********************************************************************** -->
198<div class="doc_section">
199 <a name="externalproj">External Projects Using LLVM 2.5</a>
200</div>
201<!-- *********************************************************************** -->
202
203<!--=========================================================================-->
204<div class="doc_subsection">
205<a name="pure">Pure</a>
206</div>
207
208<div class="doc_text">
209<p>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]210<a href="http://pure-lang.googlecode.com/">Pure</a>
211is an algebraic/functional programming language based on term rewriting.
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]212Programs are collections of equations which are used to evaluate expressions in
213a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]214lexical closures, a hygienic macro system (also based on term rewriting),
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]215built-in list and matrix support (including list and matrix comprehensions) and
216an easy-to-use C interface. The interpreter uses LLVM as a backend to
217 JIT-compile Pure programs to fast native code.</p>
218
219<p>In addition to the usual algebraic data structures, Pure also has
220MATLAB-style matrices in order to support numeric computations and signal
221processing in an efficient way. Pure is mainly aimed at mathematical
222applications right now, but it has been designed as a general purpose language.
223The dynamic interpreter environment and the C interface make it possible to use
224it as a kind of functional scripting language for many application areas.
225</p>
226</div>
227
228
229<!--=========================================================================-->
230<div class="doc_subsection">
231<a name="ldc">LLVM D Compiler</a>
232</div>
233
234<div class="doc_text">
235<p>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]236<a href="http://www.dsource.org/projects/ldc">LDC</a> is an implementation of
237the D Programming Language using the LLVM optimizer and code generator.
238LDC project works great with the LLVM 2.5 release. General improvmenets in this
239cycle have included new inline asm constraint handling, better debug info
240support, general bugfixes, and better x86-64 support. This has allowed
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]241some major improvements in LDC, getting us much closer to being as
242fully featured as the original DMD compiler from DigitalMars.
243</p>
244</div>
245
Chris Lattnerfb23a962009-02-28 18:58:01 +0000[diff] [blame]246<!--=========================================================================-->
247<div class="doc_subsection">
248<a name="RoadsendPHP">Roadsend PHP</a>
249</div>
250
251<div class="doc_text">
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]252<p><a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
253source compiler for the PHP programming language that uses LLVM for its
254optimizer, JIT, and static compiler. This is a reimplementation of an earlier
255project that is now based on the LLVM.</p>
Chris Lattnerfb23a962009-02-28 18:58:01 +0000[diff] [blame]256</div>
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]257
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]258
259<!-- *********************************************************************** -->
260<div class="doc_section">
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]261 <a name="whatsnew">What's New in LLVM 2.5?</a>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]262</div>
263<!-- *********************************************************************** -->
264
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]265<div class="doc_text">
266
Bill Wendlingef362462008-10-27 09:27:33 +0000[diff] [blame]267<p>This release includes a huge number of bug fixes, performance tweaks, and
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]268minor improvements. Some of the major improvements and new features are listed
269in this section.
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]270</p>
271</div>
272
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]273<!--=========================================================================-->
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]274<div class="doc_subsection">
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]275<a name="majorfeatures">Major New Features</a>
276</div>
277
278<div class="doc_text">
279
Chris Lattner7fad44b2009-02-25 04:41:31 +0000[diff] [blame]280<p>LLVM 2.5 includes several major new capabilities:</p>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]281
282<ul>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]283<li>LLVM 2.5 includes a brand new <a
284href="http://en.wikipedia.org/wiki/XCore">XCore</a> backend.</li>
Chris Lattnerd02da042009-02-25 06:34:50 +0000[diff] [blame]285
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]286<li>llvm-gcc now generally supports the GFortan front-end, and the precompiled
287release binaries now support Fortran, even on Mac OS/X.</li>
Chris Lattnerd02da042009-02-25 06:34:50 +0000[diff] [blame]288
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]289<li>CMake is now used by the <a href="GettingStartedVS.html">LLVM build process
290on Windows</a>. It automatically generates Visual Studio project files (and
291more) from a set of simple text files. This makes it much easier to
292maintain. In time, we'd like to standardize on CMake for everything.</li>
Chris Lattner07bf7e92009-02-26 07:29:17 +0000[diff] [blame]293
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]294<li>LLVM 2.5 now uses (and includes) Google Test for unit testing.</li>
Chris Lattner07bf7e92009-02-26 07:29:17 +0000[diff] [blame]295
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]296<li>The LLVM native code generator now supports arbitrary precision integers.
297Types like <tt>i33</tt> have long been valid in the LLVM IR, but were previously
298only supported by the interpreter. Note that the C backend still does not
299support these.</li>
Chris Lattner3ab27b72009-02-25 07:32:53 +0000[diff] [blame]300
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]301<li>LLVM 2.5 no longer uses 'bison', so it is easier to build on Windows.</li>
Chris Lattner458e79f2008-02-10 08:18:42 +0000[diff] [blame]302</ul>
303
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]304</div>
305
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]306
307<!--=========================================================================-->
308<div class="doc_subsection">
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]309<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]310</div>
311
312<div class="doc_text">
313
Chris Lattner591ef272008-10-13 20:47:20 +0000[diff] [blame]314<p>LLVM fully supports the llvm-gcc 4.2 front-end, which marries the GCC
315front-ends and driver with the LLVM optimizer and code generator. It currently
316includes support for the C, C++, Objective-C, Ada, and Fortran front-ends.</p>
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]317
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]318<ul>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]319<li>In this release, the GCC inliner is completely disabled. Previously the GCC
320inliner was used to handle always-inline functions and other cases. This caused
321problems with code size growth, and it is completely disabled in this
322release.</li>
323
324<li>llvm-gcc (and LLVM in general) now support code generation for stack
325canaries, which is an effective form of <a
326href="http://en.wikipedia.org/wiki/Stack-smashing_protection">buffer overflow
327protection</a>. llvm-gcc supports this with the <tt>-fstack-protector</tt>
328command line option (just like GCC). In LLVM IR, you can request code
329generation for stack canaries with function attributes.
330</li>
Gabor Greif7f39fb52008-06-09 06:06:18 +0000[diff] [blame]331</ul>
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]332
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]333</div>
334
335
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]336<!--=========================================================================-->
337<div class="doc_subsection">
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]338<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]339</div>
340
341<div class="doc_text">
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]342<p>LLVM IR has several new features that are used by our existing front-ends and
343can be useful if you are writing a front-end for LLVM:</p>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]344
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]345<ul>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]346<li>The <a href="LangRef.html#i_shufflevector">shufflevector</a> instruction
347has been generalized to allow different shuffle mask width than its input
348vectors. This allows you to use shufflevector to combine two
349"&lt;4 x float&gt;" vectors into a "&lt;8 x float&gt;" for example.</li>
350
351<li>LLVM IR now supports new intrinsics for computing and acting on <a
352href="LangRef.html#int_overflow">overflow of integer operations</a>. This allows
353efficient code generation for languages that must trap or throw an exception on
354overflow. While these intrinsics work on all targets, they only generate
355efficient code on X86 so far.</li>
356
357<li>LLVM IR now supports a new <a href="LangRef.html#linkage">private
358linkage</a> type to produce labels that are stripped by the assembler before it
359produces a .o file (thus they are invisible to the linker).</li>
360
361<li>LLVM IR supports two new attributes for better alias analysis. The <a
362href="LangRef.html#paramattrs">noalias</a> attribute can now be used on the
363return value of a function to indicate that it returns new memory (e.g.
364'malloc', 'calloc', etc).</li>
365
366<li>The new <a href="LangRef.html#paramattrs">nocapture</a> attribute can be
367used on pointer arguments to functions that access through but do not return the
368pointer in a data structure that out lives the call (e.g. 'strlen', 'memcpy',
369and many others). The simplifylibcalls pass applies these attributes to
370standard libc functions.</li>
371
372<li>The parser for ".ll" files in lib/AsmParser is now completely rewritten as a
373recursive descent parser. This parser produces better error messages (including
374caret diagnostics) is less fragile (less likely to crash on strange things) does
375not leak memory, is more efficient, and eliminates LLVM's last use of the
376'bison' tool.</li>
377
378<li>Debug information representation and manipulation internals have been
379 consolidated to use a new set of classes in
380 <tt>llvm/Analysis/DebugInfo.h</tt> classes. These routines are more
381 efficient, robust, and extensible and replace the older mechanisms.
382 llvm-gcc, clang, and the code generator now use them to create and process
383 debug information.</li>
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]384
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]385</ul>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]386
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]387</div>
388
389<!--=========================================================================-->
390<div class="doc_subsection">
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]391<a name="optimizer">Optimizer Improvements</a>
392</div>
393
394<div class="doc_text">
395
Chris Lattner25879d72008-10-13 21:50:36 +0000[diff] [blame]396<p>In addition to a huge array of bug fixes and minor performance tweaks, this
397release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]398
399<ul>
400
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]401<li>The loop optimizer now improves floating point induction variables in
402several ways, including adding shadow induction variables to avoid
403"integer &lt;-&gt; floating point" conversions in loops when safe.</li>
404
405<li>The "-mem2reg" pass is now much faster on code with huge basic blocks.</li>
406
407<li>The "-jump-threading" pass is more powerful: it is iterative
408 and handles threading based on values with fully and partially redundant
409 loads.</li>
410
411<li>The "-memdep" memory dependence analysis pass (used by GVN and memcpyopt) is
412 both faster and more aggressive.</li>
413
414<li>The "-scalarrepl" scalar replacement of aggregates pass is more aggressive
415 about promoting unions to registers.</li>
Chris Lattner25879d72008-10-13 21:50:36 +0000[diff] [blame]416
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]417</ul>
418
419</div>
420
421<!--=========================================================================-->
422<div class="doc_subsection">
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]423<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]424</div>
425
426<div class="doc_text">
427
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]428<p>We have put a significant amount of work into the code generator
429infrastructure, which allows us to implement more aggressive algorithms and make
430it run faster:</p>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]431
432<ul>
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]433<li>The <a href="WritingAnLLVMBackend.html">Writing an LLVM Compiler
434Backend</a> document has been greatly expanded and is substantially more
435complete.</li>
436
437<li>The SelectionDAG type legalization logic has been completely rewritten, is
438now more powerful (it supports arbitrary precision integer types for example),
439and more correct in several corner cases. The type legalizer converts
440operations on types that are not natively supported by the target machine into
441equivalent code sequences that only use natively supported types. The old type
442legalizer is still available (for now) and will be used if
443<tt>-disable-legalize-types</tt> is passed to the code generator.
Duncan Sands966fd262009-02-25 11:50:08 +0000[diff] [blame]444</li>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]445
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]446<li>The code generator now supports widening illegal vectors to larger legal
447ones (for example, converting operations on &lt;3 x float&gt; to work on
448&lt;4 x float&gt;) which is very important for common graphics
449applications.</li>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]450
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]451<li>The assembly printers for each target are now split out into their own
452libraries that are separate from the main code generation logic. This reduces
453code size of JIT compilers by not requiring them to be linked in.</li>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]454
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]455<li>The 'fast' instruction selection path (used at -O0 and for fast JIT
456 compilers) now supports accelerating codegen for code that uses exception
457 handling constructs.</li>
458
459<li>The optional PBQP register allocator now supports register coalescing.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]460</ul>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]461</div>
462
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]463<!--=========================================================================-->
464<div class="doc_subsection">
465<a name="x86">X86-32 and X86-64 Target Improvements</a>
466</div>
467
468<div class="doc_text">
469<p>New features of the X86 target include:
470</p>
471
472<ul>
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]473<li>The "<a href="LangRef.html#int_returnaddress">llvm.returnaddress</a>"
474intrinsic (which is used to implement "__builtin_return_address") now supports
475non-zero stack depths on X86.</li>
476
477<li>The X86 backend now supports code generation of vector shift operations
478using SSE instructions.</li>
479
480<li>X86-64 code generation now takes advantage of red zone (unless
481-mno-red-zone option is specified).</li>
482
483<li>The X86 backend now supports using address space #256 in LLVM IR as a way of
484performing memory references off the GS segment register. This allows a
485front-end to take advantage of very low-level programming techniques when
486targetting X86 CPUs. See test/CodeGen/X86/movgs.ll for a simple example.</li>
487
488<li>The X86 backend now supports a <tt>-disable-mmx</tt> command line option to
489 prevent use of MMX even on chips that support it. This is important for cases
490 where code does not contain the proper "llvm.x86.mmx.emms" intrinsics.</li>
491
492<li>The X86 JIT now detects the new Intel "<a
493 href="http://en.wikipedia.org/wiki/Intel_Core_i7">Core i7</a>" and <a
494 href="http://en.wikipedia.org/wiki/Intel_Atom">Atom</a>" chips,
495 auto-configuring itself appropriately for the features of these chips.</li>
496
497<li>The JIT now supports exception handling constructs on Linux/X86-64 and
498 Darwin/x86-64.</li>
499<li>The JIT supports Thread Local Storage (TLS) on Linux/X86-32 but not yet on
500 X86-64.</li>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]501</ul>
502
503
504</div>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]505
506<!--=========================================================================-->
507<div class="doc_subsection">
Chris Lattner6b8bf782009-02-26 07:32:11 +0000[diff] [blame]508<a name="pic16">PIC16 Target Improvements</a>
509</div>
510
511<div class="doc_text">
512<p>New features of the PIC16 target include:
513</p>
514
515<ul>
516<li>Both direct and indirect load/stores work now.</li>
517<li>Logical, bitwise and conditional operations now work for integer data
518types.</li>
519<li>Function calls involving basic types work now.</li>
520<li>Support for integer arrays.</li>
521<li>Compiler can now emit libcalls for operations not support by m/c insns.</li>
522<li>Support for both data and rom address spaces.</li>
Chris Lattner6b8bf782009-02-26 07:32:11 +0000[diff] [blame]523</ul>
524
525<p>Things not yet supported:</p>
526
527<ul>
528<li>Floating point.</li>
529<li>Passing/returning aggregate types to/from functions.</li>
530<li>Variable arguments.</li>
531<li>Indirect function calls.</li>
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]532<li>Interrupts/programs.</li>
Chris Lattner6b8bf782009-02-26 07:32:11 +0000[diff] [blame]533<li>Debug info.</li>
Chris Lattner6b8bf782009-02-26 07:32:11 +0000[diff] [blame]534</ul>
535
536</div>
537
538
539<!--=========================================================================-->
540<div class="doc_subsection">
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]541<a name="llvmc">Improvements in LLVMC</a>
542</div>
543
544<div class="doc_text">
545<p>New features include:</p>
546
547<ul>
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]548<li>Beginning with LLVM 2.5, <tt>llvmc2</tt> is known as
549 just <tt>llvmc</tt>. The old <tt>llvmc</tt> driver was removed.</li>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]550
551<li>The Clang plugin was substantially improved and is now enabled
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]552 by default. The command <tt>llvmc --clang</tt> can be now used as a
553 synonym to <tt>ccc</tt>.</li>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]554
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]555<li>There is now a <tt>--check-graph</tt> option which is supposed to catch
556 common errors like multiple default edges, mismatched output/input language
557 names and cycles. In general, these checks can't be done at compile-time
558 because of the need to support plugins.</li>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]559
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]560<li>Plugins are now more flexible and can refer to compilation graph nodes and
561 options defined in other plugins. To manage dependencies, a priority-sorting
562 mechanism was introduced. This change affects the TableGen file syntax; see the
563 documentation for details.</li>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]564
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]565<li>Hooks can now be provided with arguments. The syntax is "<tt>$CALL(MyHook,
566 'Arg1', 'Arg2', 'Arg #3')</tt>".</li>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]567
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]568<li>A new option type: multi-valued option, for options that take more than one
569 argument (for example, "<tt>-foo a b c</tt>").</li>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]570
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]571<li>New option properties: '<tt>one_or_more</tt>', '<tt>zero_or_more</tt>',
572'<tt>hidden</tt>' and '<tt>really_hidden</tt>'.</li>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]573
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]574<li>The '<tt>case</tt>' expression gained an '<tt>error</tt>' action and
575 an '<tt>empty</tt>' test (equivalent to "<tt>(not (not_empty ...))</tt>").</li>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]576
577<li>Documentation now looks more consistent to the rest of the LLVM
578 docs. There is also a man page now.</li>
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]579
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]580</ul>
581
582</div>
583
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]584
585<!--=========================================================================-->
586<div class="doc_subsection">
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]587<a name="changes">Major Changes and Removed Features</a>
588</div>
589
590<div class="doc_text">
591
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]592<p>If you're already an LLVM user or developer with out-of-tree changes based
Chris Lattner7fad44b2009-02-25 04:41:31 +0000[diff] [blame]593on LLVM 2.4, this section lists some "gotchas" that you may run into upgrading
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]594from the previous release.</p>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]595
596<ul>
597
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]598<li>llvm-gcc defaults to -fno-math-errno on all X86 targets.</li>
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]599</ul>
600
601
602<p>In addition, many APIs have changed in this release. Some of the major LLVM
603API changes are:</p>
604
605<ul>
Chris Lattner7fad44b2009-02-25 04:41:31 +0000[diff] [blame]606<li>?</li>
Devang Pateldbf83832008-10-14 20:03:43 +0000[diff] [blame]607</ul>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]608
Bill Wendling87adbe42009-03-02 04:28:18 +0000[diff] [blame^]609<ul>
Chris Lattner7fad44b2009-02-25 04:41:31 +0000[diff] [blame]610<li>?</li>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]611</ul>
612
613</div>
614
615
616
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]617<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]618<div class="doc_section">
619 <a name="portability">Portability and Supported Platforms</a>
620</div>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]621<!-- *********************************************************************** -->
622
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]623<div class="doc_text">
624
John Criswell64307722004-12-08 20:35:47 +0000[diff] [blame]625<p>LLVM is known to work on the following platforms:</p>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]626
627<ul>
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]628<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattner2a092392008-11-10 05:40:34 +0000[diff] [blame]629Linux, Fedora Core and FreeBSD (and probably other unix-like systems).</li>
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]630<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit
Chris Lattner2a092392008-11-10 05:40:34 +0000[diff] [blame]631and 64-bit modes.</li>
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]632<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]633<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
634 support is available for native builds with Visual C++).</li>
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame]635<li>Sun UltraSPARC workstations running Solaris 10.</li>
John Criswelld5234922005-05-13 20:28:15 +0000[diff] [blame]636<li>Alpha-based machines running Debian GNU/Linux.</li>
Gabor Greif80ae8a72008-06-05 18:39:01 +0000[diff] [blame]637<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]638</ul>
639
Chris Lattner618a99f2008-06-05 06:57:39 +0000[diff] [blame]640<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekee3e557e2004-05-09 05:28:35 +0000[diff] [blame]641to the machine and operating system on which it is built. However, minor
642porting may be required to get LLVM to work on new platforms. We welcome your
643portability patches and reports of successful builds or error messages.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]644
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]645</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]646
647<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]648<div class="doc_section">
649 <a name="knownproblems">Known Problems</a>
650</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]651<!-- *********************************************************************** -->
652
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]653<div class="doc_text">
654
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]655<p>This section contains significant known problems with the LLVM system,
Chris Lattner2a092392008-11-10 05:40:34 +0000[diff] [blame]656listed by component. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]657href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]658there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]659
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]660</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]661
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]662<!-- ======================================================================= -->
663<div class="doc_subsection">
664 <a name="experimental">Experimental features included with this release</a>
665</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]666
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]667<div class="doc_text">
668
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]669<p>The following components of this LLVM release are either untested, known to
670be broken or unreliable, or are in early development. These components should
671not be relied on, and bugs should not be filed against them, but they may be
672useful 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]673components, please contact us on the <a
674href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]675
676<ul>
Gabor Greif20564a02008-10-14 11:31:14 +0000[diff] [blame]677<li>The MSIL, IA64, Alpha, SPU, MIPS, and PIC16 backends are experimental.</li>
Duncan Sands56448462008-06-08 20:18:35 +0000[diff] [blame]678<li>The llc "<tt>-filetype=asm</tt>" (the default) is the only supported
Chris Lattner7422bce2008-02-06 06:30:34 +0000[diff] [blame]679 value for this option.</li>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]680</ul>
681
682</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]683
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]684<!-- ======================================================================= -->
685<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]686 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]687</div>
688
689<div class="doc_text">
690
691<ul>
Anton Korobeynikov486c7d32008-06-08 10:24:13 +0000[diff] [blame]692 <li>The X86 backend does not yet support
693 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
694 floating point stack</a>. It supports the 'f' and 't' constraints, but not
695 'u'.</li>
Chris Lattnerb076b002008-06-08 21:19:07 +0000[diff] [blame]696 <li>The X86 backend generates inefficient floating point code when configured
697 to generate code for systems that don't have SSE2.</li>
Duncan Sands0bc15262008-06-08 19:38:43 +0000[diff] [blame]698 <li>Win64 code generation wasn't widely tested. Everything should work, but we
Anton Korobeynikov486c7d32008-06-08 10:24:13 +0000[diff] [blame]699 expect small issues to happen. Also, llvm-gcc cannot build mingw64 runtime
700 currently due
701 to <a href="http://llvm.org/PR2255">several</a>
Chris Lattner54d12102008-06-08 23:12:47 +0000[diff] [blame]702 <a href="http://llvm.org/PR2257">bugs</a> due to lack of support for the
703 'u' inline assembly constraint and X87 floating point inline assembly.</li>
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]704 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]705 <tt>va_arg</tt>. Currently, the llvm-gcc and front-ends support variadic
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]706 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]707</ul>
708
709</div>
710
711<!-- ======================================================================= -->
712<div class="doc_subsection">
713 <a name="ppc-be">Known problems with the PowerPC back-end</a>
714</div>
715
716<div class="doc_text">
717
718<ul>
Nicolas Geoffray77d99502007-05-15 09:21:28 +0000[diff] [blame]719<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]720compilation, and lacks support for debug information.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]721</ul>
722
723</div>
724
725<!-- ======================================================================= -->
726<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]727 <a name="arm-be">Known problems with the ARM back-end</a>
728</div>
729
730<div class="doc_text">
731
732<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]733<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands47fc0a22007-09-26 15:59:54 +0000[diff] [blame]734processors, thumb programs can crash or produce wrong
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]735results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]736<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
737</li>
Chris Lattnerb076b002008-06-08 21:19:07 +0000[diff] [blame]738<li>There is a bug in QEMU-ARM (&lt;= 0.9.0) which causes it to incorrectly
739 execute
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]740programs compiled with LLVM. Please use more recent versions of QEMU.</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]741</ul>
742
743</div>
744
745<!-- ======================================================================= -->
746<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]747 <a name="sparc-be">Known problems with the SPARC back-end</a>
748</div>
749
750<div class="doc_text">
751
752<ul>
753<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
754 support the 64-bit SPARC ABI (-m64).</li>
755</ul>
756
757</div>
758
759<!-- ======================================================================= -->
760<div class="doc_subsection">
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]761 <a name="mips-be">Known problems with the MIPS back-end</a>
762</div>
763
764<div class="doc_text">
765
766<ul>
767<li>The O32 ABI is not fully supported.</li>
768<li>64-bit MIPS targets are not supported yet.</li>
769</ul>
770
771</div>
772
773<!-- ======================================================================= -->
774<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]775 <a name="alpha-be">Known problems with the Alpha back-end</a>
776</div>
777
778<div class="doc_text">
779
780<ul>
781
782<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
783appropriate nops inserted to ensure restartability.</li>
784
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]785</ul>
786</div>
787
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]788<!-- ======================================================================= -->
789<div class="doc_subsection">
790 <a name="ia64-be">Known problems with the IA64 back-end</a>
791</div>
792
793<div class="doc_text">
794
795<ul>
Chris Lattner54d12102008-06-08 23:12:47 +0000[diff] [blame]796<li>The Itanium backend is highly experimental, and has a number of known
797 issues. We are looking for a maintainer for the Itanium backend. If you
Gabor Greife4544f72008-10-15 10:47:24 +0000[diff] [blame]798 are interested, please contact the LLVMdev mailing list.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]799</ul>
800
801</div>
802
803<!-- ======================================================================= -->
804<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]805 <a name="c-be">Known problems with the C back-end</a>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]806</div>
807
808<div class="doc_text">
809
810<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]811<li><a href="http://llvm.org/PR802">The C backend has only basic support for
812 inline assembly code</a>.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000[diff] [blame]813<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
814 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Duncan Sands56448462008-06-08 20:18:35 +0000[diff] [blame]815 C++ code compiled with llc or native compilers.</li>
Duncan Sandse09506a2008-02-10 13:40:55 +0000[diff] [blame]816<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands3aa36732009-02-25 11:51:54 +0000[diff] [blame]817<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]818</ul>
819
820</div>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]821
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]822
823<!-- ======================================================================= -->
824<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]825 <a name="c-fe">Known problems with the llvm-gcc C front-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]826</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000[diff] [blame]827
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]828<div class="doc_text">
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]829
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]830<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
831Optimization</a> on most platforms "out-of-the-box". Please inquire on the
Gabor Greife4544f72008-10-15 10:47:24 +0000[diff] [blame]832LLVMdev mailing list if you are interested.</p>
Chris Lattner44124232006-08-08 17:27:28 +0000[diff] [blame]833
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]834<p>The only major language feature of GCC not supported by llvm-gcc is
835 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
836 are only supported on some targets. For example, trampolines are only
Duncan Sands56448462008-06-08 20:18:35 +0000[diff] [blame]837 supported on some targets (these are used when you take the address of a
838 nested function).</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]839
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]840<p>If you run into GCC extensions which are not supported, please let us know.
841</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]842
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]843</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]844
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]845<!-- ======================================================================= -->
846<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]847 <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]848</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]849
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]850<div class="doc_text">
851
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]852<p>The C++ front-end is considered to be fully
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]853tested and works for a number of non-trivial programs, including LLVM
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]854itself, Qt, Mozilla, etc.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]855
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]856<ul>
Anton Korobeynikov28f08aa2008-10-11 18:27:16 +0000[diff] [blame]857<li>Exception handling works well on the X86 and PowerPC targets. Currently
Chris Lattner2a092392008-11-10 05:40:34 +0000[diff] [blame]858 only Linux and Darwin targets are supported (both 32 and 64 bit).</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]859</ul>
Chris Lattner46ecf612003-10-07 22:14:37 +0000[diff] [blame]860
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]861</div>
862
Chris Lattner7292fb12008-10-30 03:58:13 +0000[diff] [blame]863<!-- ======================================================================= -->
864<div class="doc_subsection">
865 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
866</div>
867
868<div class="doc_text">
Gabor Greife5f9d672008-11-04 21:50:59 +0000[diff] [blame]869<ul>
Chris Lattner7292fb12008-10-30 03:58:13 +0000[diff] [blame]870<li>Fortran support generally works, but there are still several unresolved bugs
871 in Bugzilla. Please see the tools/gfortran component for details.</li>
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]872
Chris Lattner7292fb12008-10-30 03:58:13 +0000[diff] [blame]873<li>The Fortran front-end currently does not build on Darwin (without tweaks)
874 due to unresolved dependencies on the C front-end.</li>
Gabor Greife5f9d672008-11-04 21:50:59 +0000[diff] [blame]875</ul>
Chris Lattner7292fb12008-10-30 03:58:13 +0000[diff] [blame]876</div>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]877
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]878<!-- ======================================================================= -->
879<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]880 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]881</div>
882
883<div class="doc_text">
884The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
885technology and problems should be expected.
886<ul>
Duncan Sands56448462008-06-08 20:18:35 +0000[diff] [blame]887<li>The Ada front-end currently only builds on X86-32. This is mainly due
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]888to lack of trampoline support (pointers to nested functions) on other platforms,
Duncan Sands56448462008-06-08 20:18:35 +0000[diff] [blame]889however it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]890which does support trampolines.</li>
891<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
Duncan Sandsd34bf762009-02-25 11:59:06 +0000[diff] [blame]892This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
893exception handling, which is used internally by the compiler.
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]894Workaround: configure with --disable-bootstrap.</li>
Duncan Sandsaef747f2008-10-13 17:27:23 +0000[diff] [blame]895<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
896and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sandsd34bf762009-02-25 11:59:06 +0000[diff] [blame]897(c380004 also fails with gcc-4.2 mainline).
898If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
899causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sandsaef747f2008-10-13 17:27:23 +0000[diff] [blame]900<li>Some gcc specific Ada tests continue to crash the compiler.</li>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]901<li>The -E binder option (exception backtraces)
902<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
903crashing if an exception is raised. Workaround: do not use -E.</li>
904<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
905or finish at a non-byte offset</a> in a record. Workaround: do not pack records
906or use representation clauses that result in a field of a non-discrete type
907starting or finishing in the middle of a byte.</li>
Chris Lattnerb076b002008-06-08 21:19:07 +0000[diff] [blame]908<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
909'main' as generated by the Ada binder to be invalid</a>.
910Workaround: hand edit the file to use pointers for <tt>argv</tt> and
911<tt>envp</tt> rather than integers.</li>
912<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
913ignored</a>.</li>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]914</ul>
915</div>
916
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]917<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]918<div class="doc_section">
919 <a name="additionalinfo">Additional Information</a>
920</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]921<!-- *********************************************************************** -->
922
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]923<div class="doc_text">
924
Chris Lattnercb5596d2005-05-16 17:13:10 +0000[diff] [blame]925<p>A wide variety of additional information is available on the <a
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]926href="http://llvm.org">LLVM web page</a>, in particular in the <a
927href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]928contains versions of the API documentation which is up-to-date with the
929Subversion version of the source code.
Misha Brukman96158092005-03-30 19:14:24 +0000[diff] [blame]930You can access versions of these documents specific to this release by going
931into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]932
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]933<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]934us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]935lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]936
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]937</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]938
939<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]940
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]941<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]942<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000[diff] [blame]943 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]945 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]947
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]948 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]949 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]950</address>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]951
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]952</body>
953</html>