Gitiles
Code Review Sign In
gerrit-public.fairphone.software / toolchain / llvm-project / d63e1c80baf7226df875927d11c2122f25d60308 / . / llvm / docs / ReleaseNotes.html
blob: 2e9ebd2bdff2f9fa7cd1a7c59b7a28d405c1474c [file] [log] [blame]
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
3<html>
4<head>
Reid Spencere4190fa2004-11-18 18:38:58 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Chris Lattnerd93b4af2010-10-03 23:09:03 +0000[diff] [blame]6 <meta encoding="utf8">
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]7 <link rel="stylesheet" href="llvm.css" type="text/css">
Dan Gohman62af9d22010-05-03 23:51:05 +0000[diff] [blame]8 <title>LLVM 2.8 Release Notes</title>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]9</head>
10<body>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]11
Dan Gohman62af9d22010-05-03 23:51:05 +0000[diff] [blame]12<div class="doc_title">LLVM 2.8 Release Notes</div>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]13
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]14<img align=right src="http://llvm.org/img/DragonSmall.png"
Gabor Greif27b166352010-04-22 10:21:43 +0000[diff] [blame]15 width="136" height="136" alt="LLVM Dragon Logo">
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]16
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]17<ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]18 <li><a href="#intro">Introduction</a></li>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]19 <li><a href="#subproj">Sub-project Status Update</a></li>
Dan Gohman62af9d22010-05-03 23:51:05 +0000[diff] [blame]20 <li><a href="#externalproj">External Projects Using LLVM 2.8</a></li>
21 <li><a href="#whatsnew">What's New in LLVM 2.8?</a></li>
Chris Lattner77a51732004-04-30 22:17:12 +0000[diff] [blame]22 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Dan Gohmanad888912008-10-14 16:23:02 +0000[diff] [blame]23 <li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]24 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]25</ol>
26
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]27<div class="doc_author">
Dan Gohmanad888912008-10-14 16:23:02 +0000[diff] [blame]28 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]29</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]30
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]31<!--
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]32<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.8
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]33release.<br>
34You may prefer the
Dan Gohman62af9d22010-05-03 23:51:05 +0000[diff] [blame]35<a href="http://llvm.org/releases/2.7/docs/ReleaseNotes.html">LLVM 2.7
36Release Notes</a>.</h1>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]37-->
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]38
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]39<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]40<div class="doc_section">
41 <a name="intro">Introduction</a>
42</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]43<!-- *********************************************************************** -->
44
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]45<div class="doc_text">
46
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]47<p>This document contains the release notes for the LLVM Compiler
Dan Gohman3b763f42010-05-03 23:52:21 +0000[diff] [blame]48Infrastructure, release 2.8. Here we describe the status of LLVM, including
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]49major improvements from the previous release and significant known problems.
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]50All LLVM releases may be downloaded from the <a
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]51href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]52
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]53<p>For more information about LLVM, including information about the latest
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]54release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattnere7525b52003-10-07 21:38:31 +0000[diff] [blame]55web site</a>. If you have questions or comments, the <a
Chris Lattner0b1c9a52010-03-17 04:41:49 +0000[diff] [blame]56href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's
57Mailing List</a> is a good place to send them.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]58
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]59<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]60main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greif355f81c2008-10-14 11:00:32 +0000[diff] [blame]61current one. To see the release notes for a specific release, please see the
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]62<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]63
64</div>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]65
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]66
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]67<!--
68Almost dead code.
69 include/llvm/Analysis/LiveValues.h => Dan
70 lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8.
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]71 GEPSplitterPass
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]72-->
73
74
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]75<!-- Features that need text if they're finished for 2.9:
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]76 combiner-aa?
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]77 strong phi elim
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]78 loop dependence analysis
Chris Lattnerbd244042010-08-28 16:33:36 +0000[diff] [blame]79 TBAA
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]80 CorrelatedValuePropagation
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]81 -->
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]82
83 <!-- Announcement, lldb, libc++ -->
Chris Lattner16be34d2010-09-29 07:25:03 +0000[diff] [blame]84
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]85
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]86<!-- *********************************************************************** -->
87<div class="doc_section">
88 <a name="subproj">Sub-project Status Update</a>
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]89</div>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]90<!-- *********************************************************************** -->
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]91
92<div class="doc_text">
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]93<p>
Dan Gohman62af9d22010-05-03 23:51:05 +0000[diff] [blame]94The LLVM 2.8 distribution currently consists of code from the core LLVM
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]95repository (which roughly includes the LLVM optimizers, code generators
96and supporting tools), the Clang repository and the llvm-gcc repository. In
97addition to this code, the LLVM Project includes other sub-projects that are in
98development. Here we include updates on these subprojects.
Bill Wendlingf170d2e2009-03-02 04:28:57 +0000[diff] [blame]99</p>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]100
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]101</div>
102
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]103
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]104<!--=========================================================================-->
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]105<div class="doc_subsection">
Chris Lattner44c09cd2008-10-13 18:11:54 +0000[diff] [blame]106<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]107</div>
108
109<div class="doc_text">
110
Chris Lattner5de7f6e2010-04-26 17:42:18 +0000[diff] [blame]111<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
112C++, and Objective-C languages. Clang aims to provide a better user experience
113through expressive diagnostics, a high level of conformance to language
114standards, fast compilation, and low memory use. Like LLVM, Clang provides a
115modular, library-based architecture that makes it suitable for creating or
116integrating with other development tools. Clang is considered a
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]117production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
118(32- and 64-bit), and for darwin-arm targets.</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]119
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]120<p>In the LLVM 2.8 time-frame, the Clang team has made many improvements:</p>
Bill Wendlingef362462008-10-27 09:27:33 +0000[diff] [blame]121
Douglas Gregor614ace62010-10-04 07:02:35 +0000[diff] [blame]122 <ul>
123 <li>Clang C++ is now feature-complete with respect to the ISO C++ 1998 and 2003 standards.</li>
124 <li>Added support for Objective-C++.</li>
125 <li>Clang now uses LLVM-MC to directly generate object code and to parse inline assembly (on Darwin).</li>
126 <li>Introduced many new warnings, including <code>-Wmissing-field-initializers</code>, <code>-Wshadow</code>, <code>-Wno-protocol</code>, <code>-Wtautological-compare</code>, <code>-Wstrict-selector-match</code>, <code>-Wcast-align</code>, <code>-Wunused</code> improvements, and greatly improved format-string checking.</li>
127 <li>Introduced the "libclang" library, a C interface to Clang intended to support IDE clients.</li>
128 <li>Added support for <code>#pragma GCC visibility</code>, <code>#pragma align</code>, and others.</li>
Duncan Sandsfb994d22010-10-04 09:11:50 +0000[diff] [blame]129 <li>Added support for SSE, ARM NEON, and Altivec.</li>
Douglas Gregor614ace62010-10-04 07:02:35 +0000[diff] [blame]130 <li>Implemented support for blocks in C++.</li>
131 <li>Implemented precompiled headers for C++.</li>
132 <li>Improved abstract syntax trees to retain more accurate source information.</li>
133 </ul>
Chris Lattner44c09cd2008-10-13 18:11:54 +0000[diff] [blame]134</div>
135
136<!--=========================================================================-->
137<div class="doc_subsection">
138<a name="clangsa">Clang Static Analyzer</a>
139</div>
140
141<div class="doc_text">
142
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]143<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a>
144 project is an effort to use static source code analysis techniques to
145 automatically find bugs in C and Objective-C programs (and hopefully <a
146 href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the
147 future</a>!). The tool is very good at finding bugs that occur on specific
148 paths through code, such as on error conditions.</p>
Chris Lattnerbcffa5a2008-10-14 00:52:49 +0000[diff] [blame]149
Chris Lattner3458ab62010-09-30 00:34:43 +0000[diff] [blame]150<p>The LLVM 2.8 release fixes a number of bugs and slightly improves precision
151 over 2.7, but there are no major new features in the release.
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]152</p>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]153
154</div>
155
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]156<!--=========================================================================-->
157<div class="doc_subsection">
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]158<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]159</div>
160
161<div class="doc_text">
162<p>
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]163<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
Duncan Sands7f9a0dc2010-09-30 17:37:34 +0000[diff] [blame]164gcc-4.5. Unlike llvm-gcc, dragonegg in theory does not require any gcc-4.5
165modifications whatsoever (currently one small patch is needed) thanks to the
166new <a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>.
167DragonEgg is a gcc plugin that makes gcc-4.5 use the LLVM optimizers and code
168generators instead of gcc's, just like with llvm-gcc.
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]169</p>
170
171<p>
Duncan Sands7f9a0dc2010-09-30 17:37:34 +0000[diff] [blame]172DragonEgg is still a work in progress, but it is able to compile a lot of code,
173for example all of gcc, LLVM and clang. Currently Ada, C, C++ and Fortran work
174well, while all other languages either don't work at all or only work poorly.
175For the moment only the x86-32 and x86-64 targets are supported, and only on
176linux and darwin (darwin may need additional gcc patches).
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]177</p>
178
179<p>
Duncan Sands7f9a0dc2010-09-30 17:37:34 +0000[diff] [blame]180The 2.8 release has the following notable changes:
181<ul>
182<li>The plugin loads faster due to exporting fewer symbols.</li>
183<li>Additional vector operations such as addps256 are now supported.</li>
184<li>Ada global variables with no initial value are no longer zero initialized,
185resulting in better optimization.</li>
186<li>The '-fplugin-arg-dragonegg-enable-gcc-optzns' flag now runs all gcc
187optimizers, rather than just a handful.</li>
188<li>Fortran programs using common variables now link correctly.</li>
189<li>GNU OMP constructs no longer crash the compiler.</li>
190</ul>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]191</p>
192
193</div>
194
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]195<!--=========================================================================-->
196<div class="doc_subsection">
197<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
198</div>
199
200<div class="doc_text">
201<p>
202The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
203a Java Virtual Machine (Java VM or JVM) that uses LLVM for static and
204just-in-time compilation. As of LLVM 2.8, VMKit now supports copying garbage
205collectors, and can be configured to use MMTk's copy mark-sweep garbage
206collector. In LLVM 2.8, the VMKit .NET VM is no longer being maintained.
207</p>
208</div>
209
210<!--=========================================================================-->
211<div class="doc_subsection">
212<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
213</div>
214
215<div class="doc_text">
216<p>
217The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
218is a simple library that provides an implementation of the low-level
219target-specific hooks required by code generation and other runtime components.
220For example, when compiling for a 32-bit target, converting a double to a 64-bit
221unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
222function. The compiler-rt library provides highly optimized implementations of
223this and other low-level routines (some are 3x faster than the equivalent
224libgcc routines).</p>
225
226<p>
227All of the code in the compiler-rt project is available under the standard LLVM
228License, a "BSD-style" license. New in LLVM 2.8, compiler_rt now supports
229soft floating point (for targets that don't have a real floating point unit),
230and includes an extensive testsuite for the "blocks" language feature and the
231blocks runtime included in compiler_rt.</p>
232
233</div>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]234
235<!--=========================================================================-->
236<div class="doc_subsection">
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]237<a name="lldb">LLDB: Low Level Debugger</a>
238</div>
239
240<div class="doc_text">
241<p>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]242<a href="http://lldb.llvm.org/">LLDB</a> is a brand new member of the LLVM
243umbrella of projects. LLDB is a next generation, high-performance debugger. It
244is built as a set of reusable components which highly leverage existing
245libraries in the larger LLVM Project, such as the Clang expression parser, the
246LLVM disassembler and the LLVM JIT.</p>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]247
248<p>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]249LLDB is in early development and not included as part of the LLVM 2.8 release,
250but is mature enough to support basic debugging scenarios on Mac OS X in C,
251Objective-C and C++. We'd really like help extending and expanding LLDB to
252support new platforms, new languages, new architectures, and new features.
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]253</p>
254
255</div>
256
257<!--=========================================================================-->
258<div class="doc_subsection">
259<a name="libc++">libc++: C++ Standard Library</a>
260</div>
261
262<div class="doc_text">
263<p>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]264<a href="http://libc++.llvm.org/">libc++</a> is another new member of the LLVM
265family. It is an implementation of the C++ standard library, written from the
266ground up to specifically target the forthcoming C++'0X standard and focus on
267delivering great performance.</p>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]268
269<p>
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]270As of the LLVM 2.8 release, libc++ is virtually feature complete, but would
271benefit from more testing and better integration with Clang++. It is also
272looking forward to the C++ committee finalizing the C++'0x standard.
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]273</p>
274
275</div>
276
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]277
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]278<!-- *********************************************************************** -->
279<div class="doc_section">
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]280 <a name="externalproj">External Open Source Projects Using LLVM 2.8</a>
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]281</div>
282<!-- *********************************************************************** -->
283
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]284<div class="doc_text">
285
286<p>An exciting aspect of LLVM is that it is used as an enabling technology for
287 a lot of other language and tools projects. This section lists some of the
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]288 projects that have already been updated to work with LLVM 2.8.</p>
Chris Lattnerdf85c892010-04-26 17:38:10 +0000[diff] [blame]289</div>
290
Chris Lattner3458ab62010-09-30 00:34:43 +0000[diff] [blame]291<!--=========================================================================-->
292<div class="doc_subsection">
293<a name="tce">TTA-based Codesign Environment (TCE)</a>
294</div>
295
296<div class="doc_text">
297<p>
298<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing
299application-specific processors (ASP) based on the Transport triggered
300architecture (TTA). The toolset provides a complete co-design flow from C/C++
301programs down to synthesizable VHDL and parallel program binaries. Processor
302customization points include the register files, function units, supported
303operations, and the interconnection network.</p>
304
305<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target
306independent optimizations and also for parts of code generation. It generates
307new LLVM-based code generators "on the fly" for the designed TTA processors and
308loads them in to the compiler backend as runtime libraries to avoid per-target
309recompilation of larger parts of the compiler chain.</p>
310
311</div>
312
313<!--=========================================================================-->
314<div class="doc_subsection">
315<a name="Horizon">Horizon Bytecode Compiler</a>
316</div>
317
318<div class="doc_text">
319<p>
320<a href="http://www.quokforge.org/projects/horizon">Horizon</a> is a bytecode
321language and compiler written on top of LLVM, intended for producing
322single-address-space managed code operating systems that
323run faster than the equivalent multiple-address-space C systems.
324More in-depth blurb is available on <a
325href="http://www.quokforge.org/projects/horizon/wiki/Wiki">the wiki</a>.</p>
326
327</div>
328
329<!--=========================================================================-->
330<div class="doc_subsection">
331<a name="clamav">Clam AntiVirus</a>
332</div>
333
334<div class="doc_text">
335<p>
336<a href=http://www.clamav.net>Clam AntiVirus</a> is an open source (GPL)
337anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail
338gateways. Since version 0.96 it has <a
339href="http://vrt-sourcefire.blogspot.com/2010/09/introduction-to-clamavs-low-level.html">bytecode
340signatures</a> that allow writing detections for complex malware. It
341uses LLVM's JIT to speed up the execution of bytecode on
342X86,X86-64,PPC32/64, falling back to its own interpreter otherwise.
343The git version was updated to work with LLVM 2.8
344</p>
345
346<p>The <a
347href="http://git.clamav.net/gitweb?p=clamav-bytecode-compiler.git;a=blob_plain;f=docs/user/clambc-user.pdf">
348ClamAV bytecode compiler</a> uses Clang and LLVM to compile a C-like
349language, insert runtime checks, and generate ClamAV bytecode.</p>
350
351</div>
352
353<!--=========================================================================-->
354<div class="doc_subsection">
355<a name="pure">Pure</a>
356</div>
357
358<div class="doc_text">
359<p>
360<a href="http://pure-lang.googlecode.com/">Pure</a>
361is an algebraic/functional
362programming language based on term rewriting. Programs are collections
363of equations which are used to evaluate expressions in a symbolic
364fashion. Pure offers dynamic typing, eager and lazy evaluation, lexical
365closures, a hygienic macro system (also based on term rewriting),
366built-in list and matrix support (including list and matrix
367comprehensions) and an easy-to-use C interface. The interpreter uses
368LLVM as a backend to JIT-compile Pure programs to fast native code.</p>
369
370<p>Pure versions 0.44 and later have been tested and are known to work with
371LLVM 2.8 (and continue to work with older LLVM releases >= 2.5).</p>
372
373</div>
374
375<!--=========================================================================-->
376<div class="doc_subsection">
377<a name="GHC">Glasgow Haskell Compiler (GHC)</a>
378</div>
379
380<div class="doc_text">
381<p>
382<a href="http://www.haskell.org/ghc/">GHC</a> is an open source,
383state-of-the-art programming suite for
384Haskell, a standard lazy functional programming language. It includes
385an optimizing static compiler generating good code for a variety of
386platforms, together with an interactive system for convenient, quick
387development.</p>
388
389<p>In addition to the existing C and native code generators, GHC 7.0 now
390supports an <a
391href="http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/Backends/LLVM">LLVM
392code generator</a>. GHC supports LLVM 2.7 and later.</p>
393
394</div>
395
396<!--=========================================================================-->
397<div class="doc_subsection">
398<a name="Clay">Clay Programming Language</a>
399</div>
400
401<div class="doc_text">
402<p>
Chris Lattner510a81a2010-09-30 01:12:09 +0000[diff] [blame]403<a href="http://tachyon.in/clay/">Clay</a> is a new systems programming
Chris Lattner3458ab62010-09-30 00:34:43 +0000[diff] [blame]404language that is specifically designed for generic programming. It makes
405generic programming very concise thanks to whole program type propagation. It
406uses LLVM as its backend.</p>
407
408</div>
Chris Lattner64694df2010-04-22 21:34:16 +0000[diff] [blame]409
Chris Lattnerca7c8962010-10-01 06:34:49 +0000[diff] [blame]410<!--=========================================================================-->
411<div class="doc_subsection">
412<a name="llvm-py">llvm-py Python Bindings for LLVM</a>
413</div>
414
415<div class="doc_text">
416<p>
417<a href="http://www.mdevan.org/llvm-py/">llvm-py</a> has been updated to work
418with LLVM 2.8. llvm-py provides Python bindings for LLVM, allowing you to write a
419compiler backend or a VM in Python.</p>
420
421</div>
422
423
Chris Lattnerd93b4af2010-10-03 23:09:03 +0000[diff] [blame]424<!--=========================================================================-->
425<div class="doc_subsection">
426<a name="FAUST">FAUST Real-Time Audio Signal Processing Language</a>
427</div>
428
429<div class="doc_text">
430<p>
431<a href="http://faust.grame.fr">FAUST</a> is a compiled language for real-time
432audio signal processing. The name FAUST stands for Functional AUdio STream. Its
433programming model combines two approaches: functional programming and block
434diagram composition. In addition with the C, C++, JAVA output formats, the
435Faust compiler can now generate LLVM bitcode, and works with LLVM 2.7 and
4362.8.</p>
437
438</div>
439
440<!--=========================================================================-->
441<div class="doc_subsection">
442<a name="jade">Jade Just-in-time Adaptive Decoder Engine</a>
443</div>
444
445<div class="doc_text">
446<p><a
447href="http://sourceforge.net/apps/trac/orcc/wiki/JadeDocumentation">Jade</a>
448(Just-in-time Adaptive Decoder Engine) is a generic video decoder engine using
449LLVM for just-in-time compilation of video decoder configurations. Those
450configurations are designed by MPEG Reconfigurable Video Coding (RVC) committee.
451MPEG RVC standard is built on a stream-based dataflow representation of
452decoders. It is composed of a standard library of coding tools written in
Duncan Sands6ad8bf62010-10-04 10:04:14 +0000[diff] [blame]453RVC-CAL language and a dataflow configuration &#8212; block diagram &#8212;
Chris Lattnerd93b4af2010-10-03 23:09:03 +0000[diff] [blame]454of a decoder.</p>
455
456<p>Jade project is hosted as part of the <a href="http://orcc.sf.net">Open
457RVC-CAL Compiler</a> and requires it to translate the RVC-CAL standard library
458of video coding tools into an LLVM assembly code.</p>
459
460</div>
461
462<!--=========================================================================-->
463<div class="doc_subsection">
464<a name="neko_llvm_jit">LLVM JIT for Neko VM</a>
465</div>
466
467<div class="doc_text">
468<p><a href="http://github.com/vava/neko_llvm_jit">Neko LLVM JIT</a>
469replaces the standard Neko JIT with an LLVM-based implementation. While not
470fully complete, it is already providing a 1.5x speedup on 64-bit systems.
471Neko LLVM JIT requires LLVM 2.8 or later.</p>
472
473</div>
474
475<!--=========================================================================-->
476<div class="doc_subsection">
477<a name="crack">Crack Scripting Language</a>
478</div>
479
480<div class="doc_text">
481<p>
482<a href="http://code.google.com/p/crack-language/">Crack</a> aims to provide
483the ease of development of a scripting language with the performance of a
484compiled language. The language derives concepts from C++, Java and Python,
485incorporating object-oriented programming, operator overloading and strong
486typing. Crack 0.2 works with LLVM 2.7, and the forthcoming Crack 0.2.1 release
487builds on LLVM 2.8.</p>
488
489</div>
490
491<!--=========================================================================-->
492<div class="doc_subsection">
493<a name="DresdenTM">Dresden TM Compiler (DTMC)</a>
494</div>
495
496<div class="doc_text">
497<p>
498<a href="http://tm.inf.tu-dresden.de">DTMC</a> provides support for
499Transactional Memory, which is an easy-to-use and efficient way to synchronize
500accesses to shared memory. Transactions can contain normal C/C++ code (e.g.,
501__transaction { list.remove(x); x.refCount--; }) and will be executed
502virtually atomically and isolated from other transactions.</p>
503
504</div>
505
506<!--=========================================================================-->
507<div class="doc_subsection">
508<a name="Kai">Kai Interpreter</a>
509</div>
510
511<div class="doc_text">
512<p>
513<a href="http://www.oriontransfer.co.nz/research/kai">Kai</a> (Japanese 会 for
514meeting/gathering) is an experimental interpreter that provides a highly
515extensible runtime environment and explicit control over the compilation
516process. Programs are defined using nested symbolic expressions, which are all
517parsed into first-class values with minimal intrinsic semantics. Kai can
518generate optimised code at run-time (using LLVM) in order to exploit the nature
519of the underlying hardware and to integrate with external software libraries.
520It is a unique exploration into world of dynamic code compilation, and the
521interaction between high level and low level semantics.</p>
522
523</div>
524
Chris Lattner120804a2010-10-03 23:49:06 +0000[diff] [blame]525<!--=========================================================================-->
526<div class="doc_subsection">
527<a name="OSL">OSL: Open Shading Language</a>
528</div>
529
530<div class="doc_text">
531<p>
532<a href="http://code.google.com/p/openshadinglanguage/">OSL</a> is a shading
533language designed for use in physically based renderers and in particular
534production rendering. By using LLVM instead of the interpreter, it was able to
535meet its performance goals (&gt;= C-code) while retaining the benefits of
536runtime specialization and a portable high-level language.
537</p>
538
539</div>
540
541
Chris Lattnerca7c8962010-10-01 06:34:49 +0000[diff] [blame]542
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]543<!-- *********************************************************************** -->
544<div class="doc_section">
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]545 <a name="whatsnew">What's New in LLVM 2.8?</a>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]546</div>
547<!-- *********************************************************************** -->
548
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]549<div class="doc_text">
550
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]551<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]552minor improvements. Some of the major improvements and new features are listed
553in this section.
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]554</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]555
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]556</div>
557
558<!--=========================================================================-->
559<div class="doc_subsection">
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]560<a name="majorfeatures">Major New Features</a>
561</div>
562
563<div class="doc_text">
564
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]565<p>LLVM 2.8 includes several major new capabilities:</p>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]566
567<ul>
Chris Lattnerfcc65a72010-10-04 02:42:39 +0000[diff] [blame]568<li>As mentioned above, <a href="#libc++">libc++</a> and <a
569 href="#lldb">LLDB</a> are major new additions to the LLVM collective.</li>
570<li>LLVM 2.8 now has pretty decent support for debugging optimized code. You
571 should be able to reliably get debug info for function arguments, assuming
572 that the value is actually available where you have stopped.</li>
573</ul>
574<li>A new 'llvm-diff' tool is available that does a semantic diff of .ll
575 files.</li>
576<li>The <a href="#mc">MC subproject</a> has made major progress in this release.
577 Direct .o file writing support for darwin/x86[-64] is now reliable and
578 support for other targets and object file formats are in progress.</li>
Chris Lattner458e79f2008-02-10 08:18:42 +0000[diff] [blame]579</ul>
Chris Lattner10a3cc42010-03-17 06:41:58 +0000[diff] [blame]580
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]581</div>
582
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]583<!--=========================================================================-->
584<div class="doc_subsection">
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]585<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]586</div>
587
588<div class="doc_text">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]589<p>LLVM IR has several new features for better support of new targets and that
590expose new optimization opportunities:</p>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]591
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]592<ul>
Chris Lattnerfcc65a72010-10-04 02:42:39 +0000[diff] [blame]593<li>The <a href="LangRef.html#int_libc">memcpy, memmove, and memset</a>
594 intrinsics now take address space qualified pointers and a bit to indicate
595 whether the transfer is "<a href="LangRef.html#volatile">volatile</a>" or not.
596</li>
597<li>Per-instruction debug info metadata is much faster and uses less memory by
598 using the new DebugLoc class.</li>
599<li>LLVM IR now has a more formalized concept of "<a
600 href="LangRef.html#trapvalues">trap values</a>", which allow the optimizer
601 to optimize more aggressively in the presence of undefined behavior, while
602 still producing predictable results.</li>
603<li>LLVM IR now supports two new <a href="LangRef.html#linkage">linkage
604 types</a> (linker_private_weak and linker_private_weak_def_auto) which map
605 onto some obscure MachO concepts.</li>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]606</ul>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]607
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]608</div>
609
610<!--=========================================================================-->
611<div class="doc_subsection">
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]612<a name="optimizer">Optimizer Improvements</a>
613</div>
614
615<div class="doc_text">
616
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]617<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattner25879d72008-10-13 21:50:36 +0000[diff] [blame]618release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]619
620<ul>
Chris Lattnerfcc65a72010-10-04 02:42:39 +0000[diff] [blame]621<li>As mentioned above, the optimizer now has support for updating debug
622 information as it goes. A key aspect of this is the new <a
623 href="SourceLevelDebugging.html#format_common_value">llvm.dbg.value</a>
624 intrinsic. This intrinsic represents debug info for variables that are
625 promoted to SSA values (typically by mem2reg or the -scalarrepl passes).</li>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]626
Chris Lattnerfcc65a72010-10-04 02:42:39 +0000[diff] [blame]627<li>The JumpThreading pass is now much more aggressive about implied value
628 relations, allowing it to thread conditions like "a == 4" when a is known to
629 be 13 in one of the predecessors of a block. It does this in conjunction
630 with the new LazyValueInfo analysis pass.</li>
631<li>The new RegionInfo analysis pass identifies single-entry single-exit regions
632 in the CFG. You can play with it with the "opt -regions analyze" or
633 "opt -view-regions" commands.</li>
Duncan Sands6ad8bf62010-10-04 10:04:14 +0000[diff] [blame]634<li>The loop optimizer has significantly improved strength reduction and analysis
Chris Lattnerfcc65a72010-10-04 02:42:39 +0000[diff] [blame]635 capabilities. Notably it is able to build on the trap value and signed
636 integer overflow information to optimize &lt;= and &gt;= loops.</li>
637<li>The CallGraphSCCPassManager now has some basic support for iterating within
638 an SCC when a optimizer devirtualizes a function call. This allows inlining
639 through indirect call sites that are devirtualized by store-load forwarding
640 and other optimizations.</li>
641<li>The new <A href="Passes.html#loweratomic">-loweratomic</a> pass is available
642 to lower atomic instructions into their non-atomic form. This can be useful
643 to optimize generic code that expects to run in a single-threaded
644 environment.</li>
645</ul>
646
647<!--
648<p>In addition to these features that are done in 2.8, there is preliminary
649 support in the release for Type Based Alias Analysis
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]650 Preliminary work on TBAA but not usable in 2.8.
651 New CorrelatedValuePropagation pass, not on by default in 2.8 yet.
Chris Lattnerfcc65a72010-10-04 02:42:39 +0000[diff] [blame]652-->
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]653
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]654</div>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]655
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]656<!--=========================================================================-->
657<div class="doc_subsection">
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]658<a name="mc">MC Level Improvements</a>
659</div>
660
661<div class="doc_text">
662<p>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]663The LLVM Machine Code (aka MC) subsystem was created to solve a number
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]664of problems in the realm of assembly, disassembly, object file format handling,
665and a number of other related areas that CPU instruction-set level tools work
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]666in.</p>
667
668<p>The MC subproject has made great leaps in LLVM 2.8. For example, support for
669 directly writing .o files from LLC (and clang) now works reliably for
670 darwin/x86[-64] (including inline assembly support) and the integrated
671 assembler is turned on by default in Clang for these targets. This provides
672 improved compile times among other things.</p>
673
674<ul>
675<li>The entire compiler has converted over to using the MCStreamer assembler API
676 instead of writing out a .s file textually.</li>
677<li>The "assembler parser" is far more mature than in 2.7, supporting a full
678 complement of directives, now supports assembler macros, etc.</li>
679<li>The "assembler backend" has been completed, including support for relaxation
680 relocation processing and all the other things that an assembler does.</li>
681<li>The MachO file format support is now fully functional and works.</li>
682<li>The MC disassembler now fully supports ARM and Thumb. ARM assembler support
683 is still in early development though.</li>
684<li>The X86 MC assembler now supports the X86 AES and AVX instruction set.</li>
Chris Lattner9fd1e922010-10-04 03:58:12 +0000[diff] [blame]685<li>Work on ELF and COFF object files and ARM target support is well underway,
686 but isn't useful yet in LLVM 2.8. Please contact the llvmdev mailing list
687 if you're interested in this.</li>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]688</ul>
689
690<p>For more information, please see the <a
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]691href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
692LLVM MC Project Blog Post</a>.
693</p>
694
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]695</div>
696
697
Chris Lattnerf25bc192010-09-30 16:31:33 +0000[diff] [blame]698<!--=========================================================================-->
699<div class="doc_subsection">
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]700<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]701</div>
702
703<div class="doc_text">
704
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]705<p>We have put a significant amount of work into the code generator
706infrastructure, which allows us to implement more aggressive algorithms and make
707it run faster:</p>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]708
709<ul>
Chris Lattner9fd1e922010-10-04 03:58:12 +0000[diff] [blame]710<li>The clang/gcc -momit-leaf-frame-pointer argument is now supported.</li>
711<li>The clang/gcc -ffunction-sections and -fdata-sections arguments are now
712 supported on ELF targets (like GCC).</li>
713<li>The MachineCSE pass is now tuned and on by default. It eliminates common
714 subexpressions that are exposed when lowering to machine instructions.</li>
715<li>The "local" register allocator was replaced by a new "fast" register
716 allocator. This new allocator (which is often used at -O0) is substantially
717 faster and produces better code than the old local register allocator.</li>
718<li>A new LLC "-regalloc=default" option is available, which automatically
719 chooses a register allocator based on the -O optimization level.</li>
720<li>The common code generator code was modified to promote illegal argument and
721 return value vectors to wider ones when possible instead of scalarizing
722 them. For example, &lt;3 x float&gt; will now pass in one SSE register
723 instead of 3 on X86. This generates substantially better code since the
724 rest of the code generator was already expecting this.</li>
725<li>The code generator uses a new "COPY" machine instruction. This speeds up
726 the code generator and eliminates the need for targets to implement the
727 isMoveInstr hook. Also, the copyRegToReg hook was renamed to copyPhysReg
728 and simplified.</li>
729<li>The code generator now has a "LocalStackSlotPass", which optimizes stack
730 slot access for targets (like ARM) that have limited stack displacement
731 addressing.</li>
732<li>A new "PeepholeOptimizer" is available, which eliminates sign and zero
733 extends, and optimizes away compare instructions when the condition result
734 is available from a previous instruction.</li>
735<li>Atomic operations now get legalized into simpler atomic operations if not
Duncan Sands6ad8bf62010-10-04 10:04:14 +0000[diff] [blame]736 natively supported, easing the implementation burden on targets.</li>
Chris Lattner9fd1e922010-10-04 03:58:12 +0000[diff] [blame]737<li>The bottom-up pre-allocation scheduler is now register pressure aware,
738 allowing it to avoid overscheduling in high pressure situations while still
739 aggressively scheduling when registers are available.</li>
740<li>A new instruction-level-parallelism pre-allocation scheduler is available,
741 which is also register pressure aware. This scheduler has shown substantial
742 wins on X86-64 and is on by default.</li>
743<li>The tblgen type inference algorithm was rewritten to be more consistent and
744 diagnose more target bugs. If you have an out-of-tree backend, you may
745 find that it finds bugs in your target description. This support also
746 allows limited support for writing patterns for instructions that return
747 multiple results (e.g. a virtual register and a flag result). The
748 'parallel' modifier in tblgen was removed, you should use the new support
749 for multiple results instead.</li>
750<li>A new (experimental) "-rendermf" pass is available which renders a
751 MachineFunction into HTML, showing live ranges and other useful
752 details.</li>
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]753<li>The new SubRegIndex tablegen class allows subregisters to be indexed
754 symbolically instead of numerically. If your target uses subregisters you
755 will need to adapt to use SubRegIndex when you upgrade to 2.8.</li>
Chris Lattner9fd1e922010-10-04 03:58:12 +0000[diff] [blame]756<!-- SplitKit -->
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]757
Chris Lattner9fd1e922010-10-04 03:58:12 +0000[diff] [blame]758<li>The -fast-isel instruction selection path (used at -O0 on X86) was rewritten
759 to work bottom-up on basic blocks instead of top down. This makes it
760 slightly faster (because the MachineDCE pass is not needed any longer) and
761 allows it to generate better code in some cases.</li>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]762
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]763</ul>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]764</div>
765
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]766<!--=========================================================================-->
767<div class="doc_subsection">
768<a name="x86">X86-32 and X86-64 Target Improvements</a>
769</div>
770
771<div class="doc_text">
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]772<p>New features and major changes in the X86 target include:
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]773</p>
774
775<ul>
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]776<li>The X86 backend now supports holding X87 floating point stack values
777 in registers across basic blocks, dramatically improving performance of code
778 that uses long double, and when targetting CPUs that don't support SSE.</li>
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]779
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]780<li>The X86 backend now uses a SSEDomainFix pass to optimize SSE operations. On
781 Nehalem ("Core i7") and newer CPUs there is a 2 cycle latency penalty on
782 using a register in a different domain than where it was defined. This pass
783 optimizes away these stalls.</li>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]784
Duncan Sands6ad8bf62010-10-04 10:04:14 +0000[diff] [blame]785<li>The X86 backend now promotes 16-bit integer operations to 32-bits when
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]786 possible. This avoids 0x66 prefixes, which are slow on some
787 microarchitectures and bloat the code on all of them.</li>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]788
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]789<li>The X86 backend now supports the Microsoft "thiscall" calling convention,
790 and a <a href="LangRef.html#callingconv">calling convention</a> to support
791 <a href="#GHC">ghc</a>.</li>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]792
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]793<li>The X86 backend supports a new "llvm.x86.int" intrinsic, which maps onto
794 the X86 "int $42" and "int3" instructions.</li>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]795
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]796<li>At the IR level, the &lt;2 x float&gt; datatype is now promoted and passed
Duncan Sands6ad8bf62010-10-04 10:04:14 +0000[diff] [blame]797 around as a &lt;4 x float&gt; instead of being passed and returned as an MMX
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]798 vector. If you have a frontend that uses this, please pass and return a
799 &lt;2 x i32&gt; instead (using bitcasts).</li>
800
801<li>When printing .s files in verbose assembly mode (the default for clang -S),
802 the X86 backend now decodes X86 shuffle instructions and prints human
803 readable comments after the most inscrutible of them, e.g.:
804
805<pre>
806 insertps $113, %xmm3, %xmm0 <i># xmm0 = zero,xmm0[1,2],xmm3[1]</i>
807 unpcklps %xmm1, %xmm0 <i># xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1]</i>
808 pshufd $1, %xmm1, %xmm1 <i># xmm1 = xmm1[1,0,0,0]</i>
809</pre>
810</li>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]811
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]812</ul>
813
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]814</div>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]815
816<!--=========================================================================-->
817<div class="doc_subsection">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]818<a name="ARM">ARM Target Improvements</a>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]819</div>
820
821<div class="doc_text">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]822<p>New features of the ARM target include:
823</p>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]824
825<ul>
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]826<li>The ARM backend now optimizes tail calls into jumps.</li>
827<li>Scheduling is improved through the new list-hybrid scheduler as well
828 as through better modeling of structural hazards.</li>
829<li><a href="LangRef.html#int_fp16">Half float</a> instructions are now
830 supported.</li>
831<li>NEON support has been improved to model instructions which operate onto
Duncan Sands6ad8bf62010-10-04 10:04:14 +0000[diff] [blame]832 multiple consecutive registers more aggressively. This avoids lots of
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]833 extraneous register copies.</li>
834<li>The ARM backend now uses a new "ARMGlobalMerge" pass, which merges several
835 global variables into one, saving extra address computation (all the global
836 variables can be accessed via same base address) and potentially reducing
837 register pressure.</li>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]838
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]839<li>The ARM has received many minor improvements and tweaks which lead to
840substantially better performance in a wide range of different scenarios.</li>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]841
Chris Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]842<li>The ARM NEON intrinsics have been substantially reworked to reduce
843 redundancy and improve code generation. Some of the major changes are:
844 <ol>
845 <li>
846 All of the NEON load and store intrinsics (llvm.arm.neon.vld* and
847 llvm.arm.neon.vst*) take an extra parameter to specify the alignment in bytes
848 of the memory being accessed.
849 </li>
850 <li>
851 The llvm.arm.neon.vaba intrinsic (vector absolute difference and
852 accumulate) has been removed. This operation is now represented using
853 the llvm.arm.neon.vabd intrinsic (vector absolute difference) followed by a
854 vector add.
855 </li>
856 <li>
857 The llvm.arm.neon.vabdl and llvm.arm.neon.vabal intrinsics (lengthening
858 vector absolute difference with and without accumlation) have been removed.
859 They are represented using the llvm.arm.neon.vabd intrinsic (vector absolute
860 difference) followed by a vector zero-extend operation, and for vabal,
861 a vector add.
862 </li>
863 <li>
864 The llvm.arm.neon.vmovn intrinsic has been removed. Calls of this intrinsic
865 are now replaced by vector truncate operations.
866 </li>
867 <li>
868 The llvm.arm.neon.vmovls and llvm.arm.neon.vmovlu intrinsics have been
869 removed. They are now represented as vector sign-extend (vmovls) and
870 zero-extend (vmovlu) operations.
871 </li>
872 <li>
873 The llvm.arm.neon.vaddl*, llvm.arm.neon.vaddw*, llvm.arm.neon.vsubl*, and
874 llvm.arm.neon.vsubw* intrinsics (lengthening vector add and subtract) have
875 been removed. They are replaced by vector add and vector subtract operations
876 where one (vaddw, vsubw) or both (vaddl, vsubl) of the operands are either
877 sign-extended or zero-extended.
878 </li>
879 <li>
880 The llvm.arm.neon.vmulls, llvm.arm.neon.vmullu, llvm.arm.neon.vmlal*, and
881 llvm.arm.neon.vmlsl* intrinsics (lengthening vector multiply with and without
882 accumulation and subtraction) have been removed. These operations are now
883 represented as vector multiplications where the operands are either
884 sign-extended or zero-extended, followed by a vector add for vmlal or a
885 vector subtract for vmlsl. Note that the polynomial vector multiply
886 intrinsic, llvm.arm.neon.vmullp, remains unchanged.
887 </li>
888 </ol>
Bob Wilson46d65802010-09-13 17:37:55 +0000[diff] [blame]889</li>
Chris Lattnerd3f45c82010-10-04 04:39:25 +0000[diff] [blame]890
Bob Wilsone44f2982010-09-13 17:39:35 +0000[diff] [blame]891</ul>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]892</div>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]893
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]894
895<!--=========================================================================-->
896<div class="doc_subsection">
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]897<a name="changes">Major Changes and Removed Features</a>
898</div>
899
900<div class="doc_text">
901
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]902<p>If you're already an LLVM user or developer with out-of-tree changes based
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]903on LLVM 2.7, this section lists some "gotchas" that you may run into upgrading
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]904from the previous release.</p>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]905
906<ul>
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]907<li>The build configuration machinery changed the output directory names. It
Duncan Sands6ad8bf62010-10-04 10:04:14 +0000[diff] [blame]908 wasn't clear to many people that a "Release-Asserts" build was a release build
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]909 without asserts. To make this more clear, "Release" does not include
910 assertions and "Release+Asserts" does (likewise, "Debug" and
911 "Debug+Asserts").</li>
912<li>The MSIL Backend was removed, it was unsupported and broken.</li>
913<li>The ABCD, SSI, and SCCVN passes were removed. These were not fully
914 functional and their behavior has been or will be subsumed by the
915 LazyValueInfo pass.</li>
916<li>The LLVM IR 'Union' feature was removed. While this is a desirable feature
917 for LLVM IR to support, the existing implementation was half baked and
918 barely useful. We'd really like anyone interested to resurrect the work and
919 finish it for a future release.</li>
920<li>If you're used to reading .ll files, you'll probably notice that .ll file
921 dumps don't produce #uses comments anymore. To get them, run a .bc file
922 through "llvm-dis --show-annotations".</li>
Chris Lattnerfcc65a72010-10-04 02:42:39 +0000[diff] [blame]923<li>Target triples are now stored in a normalized form, and all inputs from
924 humans are expected to be normalized by Triple::normalize before being
925 stored in a module triple or passed to another library.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]926</ul>
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]927
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]928
929
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]930<p>In addition, many APIs have changed in this release. Some of the major LLVM
931API changes are:</p>
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]932<ul>
Chris Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]933<li>LLVM 2.8 changes the internal order of operands in <a
934 href="http://llvm.org/doxygen/classllvm_1_1InvokeInst.html"><tt>InvokeInst</tt></a>
935 and <a href="http://llvm.org/doxygen/classllvm_1_1CallInst.html"><tt>CallInst</tt></a>.
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]936 To be portable across releases, please use the <tt>CallSite</tt> class and the
937 high-level accessors, such as <tt>getCalledValue</tt> and
938 <tt>setUnwindDest</tt>.
Chris Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]939</li>
940<li>
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]941 You can no longer pass use_iterators directly to cast&lt;&gt; (and similar),
942 because these routines tend to perform costly dereference operations more
943 than once. You have to dereference the iterators yourself and pass them in.
Chris Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]944</li>
945<li>
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]946 llvm.memcpy.*, llvm.memset.*, llvm.memmove.* intrinsics take an extra
947 parameter now ("i1 isVolatile"), totaling 5 parameters, and the pointer
948 operands are now address-space qualified.
Chris Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]949 If you were creating these intrinsic calls and prototypes yourself (as opposed
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]950 to using Intrinsic::getDeclaration), you can use
951 UpgradeIntrinsicFunction/UpgradeIntrinsicCall to be portable accross releases.
Chris Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]952</li>
953<li>
954 SetCurrentDebugLocation takes a DebugLoc now instead of a MDNode.
955 Change your code to use
956 SetCurrentDebugLocation(DebugLoc::getFromDILocation(...)).
957</li>
958<li>
Chris Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]959 The <tt>RegisterPass</tt> and <tt>RegisterAnalysisGroup</tt> templates are
960 considered deprecated, but continue to function in LLVM 2.8. Clients are
961 strongly advised to use the upcoming <tt>INITIALIZE_PASS()</tt> and
962 <tt>INITIALIZE_AG_PASS()</tt> macros instead.
Chris Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]963</li>
964<li>
965 The constructor for the Triple class no longer tries to understand odd triple
966 specifications. Frontends should ensure that they only pass valid triples to
967 LLVM. The Triple::normalize utility method has been added to help front-ends
968 deal with funky triples.
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]969</li>
970
Chris Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]971<li>
972 Some APIs got renamed:
973 <ul>
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]974 <li>llvm_report_error -&gt; report_fatal_error</li>
975 <li>llvm_install_error_handler -&gt; install_fatal_error_handler</li>
976 <li>llvm::DwarfExceptionHandling -&gt; llvm::JITExceptionHandling</li>
977 <li>VISIBILITY_HIDDEN -&gt; LLVM_LIBRARY_VISIBILITY</li>
Chris Lattner743bc472010-10-02 22:44:15 +0000[diff] [blame]978 </ul>
979</li>
980
Devang Pateldbf83832008-10-14 20:03:43 +0000[diff] [blame]981</ul>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]982
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]983</div>
984
985
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]986<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]987<div class="doc_section">
988 <a name="knownproblems">Known Problems</a>
989</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]990<!-- *********************************************************************** -->
991
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]992<div class="doc_text">
993
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]994<p>This section contains significant known problems with the LLVM system,
Chris Lattner2a092392008-11-10 05:40:34 +0000[diff] [blame]995listed by component. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]996href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]997there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]998
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]999</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1000
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]1001<!-- ======================================================================= -->
1002<div class="doc_subsection">
1003 <a name="experimental">Experimental features included with this release</a>
1004</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1005
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]1006<div class="doc_text">
1007
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]1008<p>The following components of this LLVM release are either untested, known to
1009be broken or unreliable, or are in early development. These components should
1010not be relied on, and bugs should not be filed against them, but they may be
1011useful 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]1012components, please contact us on the <a
1013href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]1014
1015<ul>
Chris Lattnera7f45cf2010-10-04 01:29:06 +0000[diff] [blame]1016<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, PIC16, SystemZ
1017 and XCore backends are experimental.</li>
Chris Lattnerbf1cf672010-10-02 21:59:30 +0000[diff] [blame]1018<li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets
1019 other than darwin-i386 and darwin-x86_64.</li>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]1020</ul>
1021
1022</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1023
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1024<!-- ======================================================================= -->
1025<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1026 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]1027</div>
1028
1029<div class="doc_text">
1030
1031<ul>
Anton Korobeynikov486c7d32008-06-08 10:24:13 +0000[diff] [blame]1032 <li>The X86 backend does not yet support
1033 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
1034 floating point stack</a>. It supports the 'f' and 't' constraints, but not
1035 'u'.</li>
Duncan Sands0bc15262008-06-08 19:38:43 +0000[diff] [blame]1036 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]1037 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]1038 runtime currently due to lack of support for the 'u' inline assembly
1039 constraint and for X87 floating point inline assembly.</li>
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]1040 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]1041 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]1042 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1043</ul>
1044
1045</div>
1046
1047<!-- ======================================================================= -->
1048<div class="doc_subsection">
1049 <a name="ppc-be">Known problems with the PowerPC back-end</a>
1050</div>
1051
1052<div class="doc_text">
1053
1054<ul>
Nicolas Geoffray77d99502007-05-15 09:21:28 +0000[diff] [blame]1055<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]1056compilation, and lacks support for debug information.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1057</ul>
1058
1059</div>
1060
1061<!-- ======================================================================= -->
1062<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]1063 <a name="arm-be">Known problems with the ARM back-end</a>
1064</div>
1065
1066<div class="doc_text">
1067
1068<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]1069<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands47fc0a22007-09-26 15:59:54 +0000[diff] [blame]1070processors, thumb programs can crash or produce wrong
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]1071results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]1072<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]1073</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]1074</ul>
1075
1076</div>
1077
1078<!-- ======================================================================= -->
1079<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1080 <a name="sparc-be">Known problems with the SPARC back-end</a>
1081</div>
1082
1083<div class="doc_text">
1084
1085<ul>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]1086<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1087 support the 64-bit SPARC ABI (-m64).</li>
1088</ul>
1089
1090</div>
1091
1092<!-- ======================================================================= -->
1093<div class="doc_subsection">
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]1094 <a name="mips-be">Known problems with the MIPS back-end</a>
1095</div>
1096
1097<div class="doc_text">
1098
1099<ul>
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]1100<li>64-bit MIPS targets are not supported yet.</li>
1101</ul>
1102
1103</div>
1104
1105<!-- ======================================================================= -->
1106<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1107 <a name="alpha-be">Known problems with the Alpha back-end</a>
1108</div>
1109
1110<div class="doc_text">
1111
1112<ul>
1113
1114<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
1115appropriate nops inserted to ensure restartability.</li>
1116
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]1117</ul>
1118</div>
1119
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1120<!-- ======================================================================= -->
1121<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]1122 <a name="c-be">Known problems with the C back-end</a>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1123</div>
1124
1125<div class="doc_text">
1126
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]1127<p>The C backend has numerous problems and is not being actively maintained.
1128Depending on it for anything serious is not advised.</p>
1129
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1130<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]1131<li><a href="http://llvm.org/PR802">The C backend has only basic support for
1132 inline assembly code</a>.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000[diff] [blame]1133<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
1134 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif75b2f762009-03-02 12:02:51 +0000[diff] [blame]1135 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandse09506a2008-02-10 13:40:55 +0000[diff] [blame]1136<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands3aa36732009-02-25 11:51:54 +0000[diff] [blame]1137<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1138</ul>
1139
1140</div>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]1141
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1142
1143<!-- ======================================================================= -->
1144<div class="doc_subsection">
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]1145 <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1146</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000[diff] [blame]1147
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1148<div class="doc_text">
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]1149
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]1150<p>llvm-gcc is generally very stable for the C family of languages. The only
1151 major language feature of GCC not supported by llvm-gcc is the
1152 <tt>__builtin_apply</tt> family of builtins. However, some extensions
1153 are only supported on some targets. For example, trampolines are only
1154 supported on some targets (these are used when you take the address of a
1155 nested function).</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1156
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame]1157<p>Fortran support generally works, but there are still several unresolved bugs
1158 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
1159 tools/gfortran component for details. Note that llvm-gcc is missing major
1160 Fortran performance work in the frontend and library that went into GCC after
1161 4.2. If you are interested in Fortran, we recommend that you consider using
1162 <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1163
Duncan Sandsd63e1c82010-10-04 10:06:56 +0000[diff] [blame^]1164<p>The llvm-gcc 4.2 Ada compiler has basic functionality, but is no longer being
1165actively maintained. If you are interested in Ada, we recommend that you
1166consider using <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1167</div>
1168
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1169<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1170<div class="doc_section">
1171 <a name="additionalinfo">Additional Information</a>
1172</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1173<!-- *********************************************************************** -->
1174
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1175<div class="doc_text">
1176
Chris Lattnercb5596d2005-05-16 17:13:10 +0000[diff] [blame]1177<p>A wide variety of additional information is available on the <a
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]1178href="http://llvm.org">LLVM web page</a>, in particular in the <a
1179href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]1180contains versions of the API documentation which is up-to-date with the
1181Subversion version of the source code.
Misha Brukman96158092005-03-30 19:14:24 +0000[diff] [blame]1182You can access versions of these documents specific to this release by going
1183into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1184
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1185<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]1186us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]1187lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1188
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1189</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1190
1191<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1192
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1193<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1194<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000[diff] [blame]1195 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]1196 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1197 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]1198 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1199
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]1200 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1201 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1202</address>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1203
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1204</body>
1205</html>