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gerrit-public.fairphone.software / toolchain / llvm-project / 862b35372f1c79b11f93b1aa5e5c97c7b86b5efd / . / 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"
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">
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]6 <link rel="stylesheet" href="llvm.css" type="text/css">
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]7 <title>LLVM 2.7 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
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]11<div class="doc_title">LLVM 2.7 Release Notes</div>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]12
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]13<img align=right src="http://llvm.org/img/DragonSmall.png"
14 width="136" height="136">
15
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]16<ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#intro">Introduction</a></li>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]18 <li><a href="#subproj">Sub-project Status Update</a></li>
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]19 <li><a href="#externalproj">External Projects Using LLVM 2.7</a></li>
20 <li><a href="#whatsnew">What's New in LLVM 2.7?</a></li>
Chris Lattner77a51732004-04-30 22:17:12 +0000[diff] [blame]21 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]22 <li><a href="#portability">Portability and Supported Platforms</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 Lattner06971182010-04-13 06:37:00 +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
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]35<a href="http://llvm.org/releases/2.6/docs/ReleaseNotes.html">LLVM 2.7
Chris Lattner06971182010-04-13 06:37:00 +0000[diff] [blame]36Release Notes</a>.</h1>-->
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]37
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]38<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]39<div class="doc_section">
40 <a name="intro">Introduction</a>
41</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]42<!-- *********************************************************************** -->
43
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]44<div class="doc_text">
45
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]46<p>This document contains the release notes for the LLVM Compiler
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]47Infrastructure, release 2.7. Here we describe the status of LLVM, including
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]48major improvements from the previous release and significant known problems.
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]49All LLVM releases may be downloaded from the <a
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]50href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]51
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]52<p>For more information about LLVM, including information about the latest
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]53release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattnere7525b52003-10-07 21:38:31 +0000[diff] [blame]54web site</a>. If you have questions or comments, the <a
Chris Lattner0b1c9a52010-03-17 04:41:49 +0000[diff] [blame]55href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's
56Mailing List</a> is a good place to send them.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]57
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]58<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]59main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greif355f81c2008-10-14 11:00:32 +0000[diff] [blame]60current one. To see the release notes for a specific release, please see the
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]61<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]62
63</div>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]64
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]65
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]66<!--
67Almost dead code.
68 include/llvm/Analysis/LiveValues.h => Dan
69 lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8.
70 llvm/Analysis/PointerTracking.h => Edwin wants this, consider for 2.8.
Chris Lattner06971182010-04-13 06:37:00 +0000[diff] [blame]71 ABCD, GEPSplitterPass
Chris Lattner89ea59d2010-01-16 21:25:13 +0000[diff] [blame]72 MSIL backend?
Chris Lattner10a3cc42010-03-17 06:41:58 +0000[diff] [blame]73 lib/Transforms/Utils/SSI.cpp -> ABCD depends on it.
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]74-->
75
76
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]77<!-- Features that need text if they're finished for 2.7:
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]78 combiner-aa?
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]79 strong phi elim
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]80 llvm.dbg.value: variable debug info for optimized code
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]81 loop dependence analysis
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]82 -->
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]83
Chris Lattnerc4d68542008-10-12 19:47:48 +0000[diff] [blame]84 <!-- for announcement email:
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]85 Logo web page.
86 llvm devmtg
87 compiler_rt
88 KLEE web page at klee.llvm.org
89 Many new papers added to /pubs/
Chris Lattner10a3cc42010-03-17 06:41:58 +0000[diff] [blame]90 Mention gcc plugin.
Chris Lattnerd02da042009-02-25 06:34:50 +0000[diff] [blame]91 -->
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]92
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]93<!-- *********************************************************************** -->
94<div class="doc_section">
95 <a name="subproj">Sub-project Status Update</a>
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]96</div>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]97<!-- *********************************************************************** -->
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]98
99<div class="doc_text">
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]100<p>
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]101The LLVM 2.7 distribution currently consists of code from the core LLVM
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]102repository (which roughly includes the LLVM optimizers, code generators
103and supporting tools), the Clang repository and the llvm-gcc repository. In
104addition to this code, the LLVM Project includes other sub-projects that are in
105development. Here we include updates on these subprojects.
Bill Wendlingf170d2e2009-03-02 04:28:57 +0000[diff] [blame]106</p>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]107
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]108</div>
109
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]110
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]111<!--=========================================================================-->
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]112<div class="doc_subsection">
Chris Lattner44c09cd2008-10-13 18:11:54 +0000[diff] [blame]113<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]114</div>
115
116<div class="doc_text">
117
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]118<p>The <a href="http://clang.llvm.org/">Clang project</a> is ...</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]119
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]120<p>In the LLVM 2.7 time-frame, the Clang team has made many improvements:</p>
Bill Wendlingef362462008-10-27 09:27:33 +0000[diff] [blame]121
Daniel Dunbarc11b40f2008-10-14 23:25:09 +0000[diff] [blame]122<ul>
Daniel Dunbareb4bc7f2010-03-25 16:09:18 +0000[diff] [blame]123<li>FIXME: C++! Include a link to cxx_compatibility.html</li>
124
Daniel Dunbareb4bc7f2010-03-25 16:09:18 +0000[diff] [blame]125<li>CIndex API and Python bindings: Clang now includes a C API as part of the
126CIndex library. Although we make make some changes to the API in the future, it
127is intended to be stable and has been designed for use by external projects. See
128the Clang
129doxygen <a href="http://clang.llvm.org/doxygen/group__CINDEX.html">CIndex</a>
130documentation for more details. The CIndex API also includings an preliminary
131set of Python bindings.</li>
132
133<li>ARM Support: Clang now has ABI support for both the Darwin and Linux ARM
134ABIs. Coupled with many improvements to the LLVM ARM backend, Clang is now
135suitable for use as a a beta quality ARM compiler.</li>
Bill Wendling87adbe42009-03-02 04:28:18 +0000[diff] [blame]136</ul>
Chris Lattner44c09cd2008-10-13 18:11:54 +0000[diff] [blame]137</div>
138
139<!--=========================================================================-->
140<div class="doc_subsection">
141<a name="clangsa">Clang Static Analyzer</a>
142</div>
143
144<div class="doc_text">
145
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]146<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a>
147 project is an effort to use static source code analysis techniques to
148 automatically find bugs in C and Objective-C programs (and hopefully <a
149 href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the
150 future</a>!). The tool is very good at finding bugs that occur on specific
151 paths through code, such as on error conditions.</p>
Chris Lattnerbcffa5a2008-10-14 00:52:49 +0000[diff] [blame]152
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]153<p>In the LLVM 2.7 time-frame, the analyzer core has made several major and
154 minor improvements, including better support for tracking the fields of
155 structures, initial support (not enabled by default yet) for doing
156 interprocedural (cross-function) analysis, and new checks have been added.
157</p>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]158
159</div>
160
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]161<!--=========================================================================-->
162<div class="doc_subsection">
Nicolas Geoffraye5ec9322008-10-14 19:23:04 +0000[diff] [blame]163<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]164</div>
165
166<div class="doc_text">
167<p>
Nicolas Geoffraye5ec9322008-10-14 19:23:04 +0000[diff] [blame]168The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]169a JVM and a CLI Virtual Machine (Microsoft .NET is an
170implementation of the CLI) using LLVM for static and just-in-time
171compilation.</p>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]172
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]173<p>
Chris Lattneref2e5732010-03-29 18:34:13 +0000[diff] [blame]174With the release of LLVM 2.7, VMKit has shifted to a great framework for writing
175virtual machines. VMKit now offers precise and efficient garbage collection with
176multi-threading support, thanks to the MMTk memory management toolkit, as well
177as just in time and ahead of time compilation with LLVM. The major changes in
178VMKit 0.27 are:</p>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]179
Nicolas Geoffraye5ec9322008-10-14 19:23:04 +0000[diff] [blame]180<ul>
181
Chris Lattneref2e5732010-03-29 18:34:13 +0000[diff] [blame]182<li>Garbage collection: VMKit now uses the MMTk toolkit for garbage collectors.
183 The first collector to be ported is the MarkSweep collector, which is precise,
184 and drastically improves the performance of VMKit.</li>
185<li>Line number information in the JVM: by using the debug metadata of LLVM, the
186 JVM now supports precise line number information, useful when printing a stack
187 trace.</li>
188<li>Interface calls in the JVM: we implemented a variant of the Interface Method
189 Table technique for interface calls in the JVM.
190</li>
Nicolas Geoffraye5ec9322008-10-14 19:23:04 +0000[diff] [blame]191
192</ul>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]193</div>
194
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]195
196<!--=========================================================================-->
197<div class="doc_subsection">
198<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
199</div>
200
201<div class="doc_text">
202<p>
203The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
204is a simple library that provides an implementation of the low-level
205target-specific hooks required by code generation and other runtime components.
206For example, when compiling for a 32-bit target, converting a double to a 64-bit
207unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
208function. The compiler-rt library provides highly optimized implementations of
209this and other low-level routines (some are 3x faster than the equivalent
210libgcc routines).</p>
211
212<p>
213All of the code in the compiler-rt project is available under the standard LLVM
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]214License, a "BSD-style" license. New in LLVM 2.7: compiler_rt now
215supports ARM targets.</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]216
217</div>
218
219<!--=========================================================================-->
220<div class="doc_subsection">
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]221<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]222</div>
223
224<div class="doc_text">
225<p>
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]226<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
227gcc-4.5. Unlike llvm-gcc, which makes many intrusive changes to the underlying
228gcc-4.2 code, dragonegg in theory does not require any gcc-4.5 modifications
229whatsoever (currently one small patch is needed). This is thanks to the new
230<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>, which
231makes it possible to modify the behaviour of gcc at runtime by loading a plugin,
232which is nothing more than a dynamic library which conforms to the gcc plugin
233interface. DragonEgg is a gcc plugin that causes the LLVM optimizers to be run
234instead of the gcc optimizers, and the LLVM code generators instead of the gcc
235code generators, just like llvm-gcc. To use it, you add
236"-fplugin=path/dragonegg.so" to the gcc-4.5 command line, and gcc-4.5 magically
237becomes llvm-gcc-4.5!
238</p>
239
240<p>
241DragonEgg is still a work in progress. Currently C works very well, while C++,
242Ada and Fortran work fairly well. All other languages either don't work at all,
243or only work poorly. For the moment only the x86-32 and x86-64 targets are
Duncan Sands4dd125e2010-04-20 19:40:58 +0000[diff] [blame]244supported, and only on linux and darwin (darwin needs an additional gcc patch).
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]245</p>
246
247<p>
Duncan Sandsfe291172010-04-21 13:51:48 +0000[diff] [blame]248DragonEgg is a new project which is seeing its first release with llvm-2.7.
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]249</p>
250
251</div>
252
253
254<!--=========================================================================-->
255<div class="doc_subsection">
256<a name="mc">llvm-mc: Machine Code Toolkit</a>
257</div>
258
259<div class="doc_text">
260<p>
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]261The LLVM Machine Code (aka MC) sub-project of LLVM was created to solve a number
262of problems in the realm of assembly, disassembly, object file format handling,
263and a number of other related areas that CPU instruction-set level tools work
264in. It is a sub-project of LLVM which provides it with a number of advantages
265over other compilers that do not have tightly integrated assembly-level tools.
266For a gentle introduction, please see the <a
267href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
268LLVM MC Project Blog Post</a>.
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]269</p>
270
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]271<p>2.7 includes major parts of the work required by the new MC Project. A few
272 targets have been refactored to support it, and work is underway to support a
273 native assembler in LLVM. This work is not complete in LLVM 2.7, but you has
274 made substantially more progress on LLVM mainline.</p>
275
276<p>One minor example of what MC can do is to transcode an AT&amp;T syntax
277 X86 .s file into intel syntax. You can do this with something like:</p>
278
279<pre>
280 llvm-mc foo.s -output-asm-variant=1 -o foo-intel.s
281</pre>
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]282</p>
283
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]284</div>
285
286
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]287<!-- *********************************************************************** -->
288<div class="doc_section">
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]289 <a name="externalproj">External Open Source Projects Using LLVM 2.7</a>
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]290</div>
291<!-- *********************************************************************** -->
292
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]293<div class="doc_text">
294
295<p>An exciting aspect of LLVM is that it is used as an enabling technology for
296 a lot of other language and tools projects. This section lists some of the
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]297 projects that have already been updated to work with LLVM 2.7.</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]298</div>
299
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]300<!--=========================================================================-->
301<div class="doc_subsection">
302<a name="pure">Pure</a>
303</div>
304
305<div class="doc_text">
306<p>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]307<a href="http://pure-lang.googlecode.com/">Pure</a>
308is an algebraic/functional programming language based on term rewriting.
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]309Programs are collections of equations which are used to evaluate expressions in
310a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]311lexical closures, a hygienic macro system (also based on term rewriting),
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]312built-in list and matrix support (including list and matrix comprehensions) and
313an easy-to-use C interface. The interpreter uses LLVM as a backend to
314 JIT-compile Pure programs to fast native code.</p>
315
Chris Lattner6aba4862010-03-17 17:25:49 +0000[diff] [blame]316<p>Pure versions 0.43 and later have been tested and are known to work with
317LLVM 2.7 (and continue to work with older LLVM releases >= 2.5).</p>
318
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]319</div>
320
Chris Lattnerfb23a962009-02-28 18:58:01 +0000[diff] [blame]321<!--=========================================================================-->
322<div class="doc_subsection">
323<a name="RoadsendPHP">Roadsend PHP</a>
324</div>
325
326<div class="doc_text">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]327<p>
328<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
Chris Lattner0c72d8f2009-03-02 19:07:24 +0000[diff] [blame]329source implementation of the PHP programming
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]330language that uses LLVM for its optimizer, JIT and static compiler. This is a
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]331reimplementation of an earlier project that is now based on LLVM.
Chris Lattner6aba4862010-03-17 17:25:49 +0000[diff] [blame]332</p>
Chris Lattnerfb23a962009-02-28 18:58:01 +0000[diff] [blame]333</div>
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]334
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]335<!--=========================================================================-->
336<div class="doc_subsection">
337<a name="UnladenSwallow">Unladen Swallow</a>
338</div>
339
340<div class="doc_text">
341<p>
342<a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
343branch of <a href="http://python.org/">Python</a> intended to be fully
344compatible and significantly faster. It uses LLVM's optimization passes and JIT
Chris Lattner5b59a732010-03-18 06:52:15 +0000[diff] [blame]345compiler.
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]346</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]347</div>
348
349<!--=========================================================================-->
350<div class="doc_subsection">
Chris Lattnerb4a02792010-03-29 17:50:39 +0000[diff] [blame]351<a name="tce">TTA-based Codesign Environment (TCE)</a>
352</div>
353
354<div class="doc_text">
355<p>
356<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing
357application-specific processors (ASP) based on the Transport triggered
358architecture (TTA). The toolset provides a complete co-design flow from C/C++
359programs down to synthesizable VHDL and parallel program binaries. Processor
360customization points include the register files, function units, supported
361operations, and the interconnection network.</p>
362
363<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target
364independent optimizations and also for parts of code generation. It generates
365new LLVM-based code generators "on the fly" for the designed TTA processors and
366loads them in to the compiler backend as runtime libraries to avoid per-target
367recompilation of larger parts of the compiler chain.</p>
368
369</div>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]370
John Criswell9003e0f2010-04-06 14:52:14 +0000[diff] [blame]371<!--=========================================================================-->
372<div class="doc_subsection">
373<a name="safecode">SAFECode Compiler</a>
374</div>
375
376<div class="doc_text">
377<p>
378<a href="http://safecode.cs.illinois.edu">SAFECode</a> is a memory safe C
379compiler built using LLVM. It takes standard, unannotated C code, analyzes the
380code to ensure that memory accesses and array indexing operations are safe, and
381instruments the code with run-time checks when safety cannot be proven
382statically.
383</p>
384</div>
385
386
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]387<!-- *********************************************************************** -->
388<div class="doc_section">
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]389 <a name="whatsnew">What's New in LLVM 2.7?</a>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]390</div>
391<!-- *********************************************************************** -->
392
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]393<div class="doc_text">
394
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]395<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]396minor improvements. Some of the major improvements and new features are listed
397in this section.
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]398</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]399
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]400</div>
401
402<!--=========================================================================-->
403<div class="doc_subsection">
404<a name="orgchanges">LLVM Community Changes</a>
405</div>
406
407<div class="doc_text">
408
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]409<p>In addition to changes to the code, between LLVM 2.6 and 2.7, a number of
410organization changes have happened:
411</p>
412
413<ul>
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]414<li>LLVM has a new <a href="http://llvm.org/Logo.html">official logo</a>!</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]415
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]416<li>Ted Kremenek and Doug Gregor have stepped forward as <a
417 href="http://llvm.org/docs/DeveloperPolicy.html#owners">Code Owners</a> of the
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]418 Clang static analyzer and the Clang frontend, respectively.</li>
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]419
420<li>LLVM now has an <a href="http://blog.llvm.org">official Blog</a> at
421 <a href="http://blog.llvm.org">http://blog.llvm.org</a>. This is a great way
422 to learn about new LLVM-related features as they are implemented. Several
423 features in this release are already explained on the blog.</li>
424
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]425<li>The LLVM web pages are now checked into the SVN server, in the "www",
426 "www-pubs" and "www-releases" SVN modules. Previously they were hidden in a
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]427 largely inaccessible old CVS server.</li>
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]428
429<li><a href="http://llvm.org">llvm.org</a> is now hosted on a new (and much
430 faster) server. It is still graciously hosted at the University of Illinois
431 of Urbana Champaign.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]432</ul>
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]433</div>
434
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]435<!--=========================================================================-->
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]436<div class="doc_subsection">
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]437<a name="majorfeatures">Major New Features</a>
438</div>
439
440<div class="doc_text">
441
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]442<p>LLVM 2.7 includes several major new capabilities:</p>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]443
444<ul>
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]445<li>2.7 includes initial support for the <a
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]446 href="http://en.wikipedia.org/wiki/MicroBlaze">MicroBlaze</a> target.
447 MicroBlaze is a soft processor core designed for Xilinx FPGAs.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]448
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]449<li>2.7 includes a new LLVM IR "extensible metadata" feature. This feature
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]450 supports many different use cases, including allowing front-end authors to
451 encode source level information into LLVM IR, which is consumed by later
452 language-specific passes. This is a great way to do high-level optimizations
453 like devirtualization, type-based alias analysis, etc. See the <a
454 href="http://blog.llvm.org/2010/04/extensible-metadata-in-llvm-ir.html">
455 Extensible Metadata Blog Post</a> for more information.</li>
456
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]457<li>2.7 encodes <a href="SourceLevelDebugging.html">debug information</a>
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]458in a completely new way, built on extensible metadata. The new implementation
459is much more memory efficient and paves the way for improvements to optimized
460code debugging experience.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]461
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]462<li>2.7 now directly supports taking the address of a label and doing an
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]463 indirect branch through a pointer. This is particularly useful for
464 interpreter loops, and is used to implement the GCC "address of label"
465 extension. For more information, see the <a
466href="http://blog.llvm.org/2010/01/address-of-label-and-indirect-branches.html">
467Address of Label and Indirect Branches in LLVM IR Blog Post</a>.
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]468
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]469<li>2.7 is the first release to start supporting APIs for assembling and
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]470 disassembling target machine code. These APIs are useful for a variety of
471 low level clients, and are surfaced in the new "enhanced disassembly" API.
472 For more information see the <a
473 href="http://blog.llvm.org/2010/01/x86-disassembler.html">The X86
474 Disassembler Blog Post</a> for more information.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]475
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]476<li>2.7 includes major parts of the work required by the new MC Project,
477 see the <a href="#mc">MC update above</a> for more information.</li>
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]478</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]479
Chris Lattner458e79f2008-02-10 08:18:42 +0000[diff] [blame]480</ul>
Chris Lattner10a3cc42010-03-17 06:41:58 +0000[diff] [blame]481
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]482</div>
483
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]484<!--=========================================================================-->
485<div class="doc_subsection">
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]486<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]487</div>
488
489<div class="doc_text">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]490<p>LLVM IR has several new features for better support of new targets and that
491expose new optimization opportunities:</p>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]492
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]493<ul>
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]494<li>LLVM IR now supports a 16-bit "half float" data type through <a
495 href="LangRef.html#int_fp16">two new intrinsics</a> and APFloat support.</li>
496<li>LLVM IR supports two new <a href="LangRef.html#fnattrs">function
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]497 attributes</a>: inlinehint and alignstack(n). The former is a hint to the
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]498 optimizer that a function was declared 'inline' and thus the inliner should
499 weight it higher when considering inlining it. The later
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]500 indicates to the code generator that the function diverges from the platform
501 ABI on stack alignment.</li>
502<li>The new <a href="LangRef.html#int_objectsize">llvm.objectsize</a> intrinsic
503 allows the optimizer to infer the sizes of memory objects in some cases.
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]504 This intrinsic is used to implement the GCC <tt>__builtin_object_size</tt>
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]505 extension.</li>
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]506<li>LLVM IR now supports marking load and store instructions with <a
507 href="LangRef.html#i_load">"non-temporal" hints</a> (building on the new
508 metadata feature). This hint encourages the code
509 generator to generate non-temporal accesses when possible, which are useful
510 for code that is carefully managing cache behavior. Currently, only the
511 X86 backend provides target support for this feature.</li>
512
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]513<li>LLVM 2.7 has pre-alpha support for <a
Gabor Greif862b3532010-04-22 10:11:24 +0000[diff] [blame^]514 href="LangRef.html#t_union">unions in LLVM IR</a>.
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]515 Unfortunately, this support is not really usable in 2.7, so if you're
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]516 interested in pushing it forward, please help contribute to LLVM mainline.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]517</li>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]518</ul>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]519
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]520</div>
521
522<!--=========================================================================-->
523<div class="doc_subsection">
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]524<a name="optimizer">Optimizer Improvements</a>
525</div>
526
527<div class="doc_text">
528
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]529<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]530release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]531
532<ul>
533
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]534<li>The inliner reuses now merges arrays stack objects in different callees when
535 inlining multiple call sites into one function. This reduces the stack size
536 of the resultant function.</li>
537<li>The -basicaa alias analysis pass (which is the default) has been improved to
538 be less dependent on "type safe" pointers. It can now look through bitcasts
539 and other constructs more aggressively, allowing better load/store
540 optimization.</li>
541<li>The load elimination optimization in the GVN Pass [<a
542href="http://blog.llvm.org/2009/12/introduction-to-load-elimination-in-gvn.html">intro
543 blog post</a>] has been substantially improved to be more aggressive about
544 partial redundancy elimination and do more aggressive phi translation. Please
545 see the <a
546 href="http://blog.llvm.org/2009/12/advanced-topics-in-redundant-load.html">
547 Advanced Topics in Redundant Load Elimination with a Focus on PHI Translation
548 Blog Post</a> for more details.</li>
549<li>The module <a href="LangRef.html#datalayout">target data string</a> now
550 includes a notion of what the 'native' integer data types a for the target,
551 which allows various optimizations to use. This helps mid-level
552 optimizations avoid promoting complex sequences of operations to data types
553 that are not natively supported (e.g. converting i32 operations to i64 on
554 a 32-bit chip).</li>
555<li>The mid-level optimizer is now conservative when operating on a module with
556 no target data. Previously, it would default to SparcV9 settings, which is
557 not what most people expected.</li>
Chris Lattnera668b452010-04-21 06:42:24 +0000[diff] [blame]558<li>Jump threading is now much more aggressive at simplifying correlated
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]559 conditionals and threading blocks with otherwise complex logic. It has
560 subsumed the old "Conditional Propagation" pass, and -condprop has been
561 removed from LLVM 2.7.</li>
562<li>The -instcombine pass has been refactored from being one huge file to being
563 a library of its own. Internally, it uses a customized IRBuilder to clean
564 it up and simplify it.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]565
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]566<li>The optimal edge profiling pass is reliable and much more complete than in
567 2.6. It can be used with the llvm-prof tool but isn't wired up to the
568 llvm-gcc and clang command line options yet.</li>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]569
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]570<li>A new experimental alias analysis implementation, -scev-aa, has been added.
571 It uses LLVM's Scalar Evolution implementation to do symbolic analysis of
572 pointer offset expressions to disambiguate pointers. It can catch a few
573 cases that basicaa cannot, particularly in complex loop nests.</li>
Chris Lattnera668b452010-04-21 06:42:24 +0000[diff] [blame]574
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]575<li>The default pass ordering has been tweaked for improved optimization
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]576 effectiveness.</li>
Chris Lattnera668b452010-04-21 06:42:24 +0000[diff] [blame]577
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]578</ul>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]579
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]580</div>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]581
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]582
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]583<!--=========================================================================-->
584<div class="doc_subsection">
585<a name="executionengine">Interpreter and JIT Improvements</a>
586</div>
Chris Lattner25879d72008-10-13 21:50:36 +0000[diff] [blame]587
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]588<div class="doc_text">
589
590<ul>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]591<li>The JIT now supports generating debug information, which is compatible with
592the new GDB 7.0 (and later) interfaces for registering debug info for
593dynamically generated code.</li>
594
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]595<li>The JIT now <a href="http://llvm.org/PR5184">defaults
Jeffrey Yasskin9fb8ce82010-01-29 19:10:38 +0000[diff] [blame]596to compiling eagerly</a> to avoid a race condition in the lazy JIT.
597Clients that still want the lazy JIT can switch it on by calling
598<tt>ExecutionEngine::DisableLazyCompilation(false)</tt>.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]599
Jeffrey Yasskine0913882010-02-11 01:07:39 +0000[diff] [blame]600<li>It is now possible to create more than one JIT instance in the same process.
601These JITs can generate machine code in parallel,
602although <a href="http://llvm.org/docs/ProgrammersManual.html#jitthreading">you
603still have to obey the other threading restrictions</a>.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]604
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]605</ul>
606
607</div>
608
609<!--=========================================================================-->
610<div class="doc_subsection">
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]611<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]612</div>
613
614<div class="doc_text">
615
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]616<p>We have put a significant amount of work into the code generator
617infrastructure, which allows us to implement more aggressive algorithms and make
618it run faster:</p>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]619
620<ul>
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]621<li>The 'llc -asm-verbose' option (which is now the default) has been enhanced
622 to emit many useful comments to .s files indicating information about spill
623 slots and loop nest structure. This should make it much easier to read and
624 understand assembly files. This is wired up in llvm-gcc and clang to
625 the <tt>-fverbose-asm</tt> option.</li>
626
627<li>New LSR with "full strength reduction" mode. FIXME: Description?</li>
628
629<li>A new codegen level Common Subexpression Elimination pass (MachineCSE)
630 is available and enabled by default. It catches redundancies exposed by
631 lowering.</li>
632<li>A new pre-register-allocation tail duplication pass is available and enabled
633 by default, it can substantially improve branch prediction quality in some
634 cases.</li>
635<li>A new sign and zero extension optimization pass (OptimizeExtsPass)
636 is available and enabled by default. This pass can takes advantage
637 architecture features like x86-64 implicit zero extension behavior and
638 sub-registers.</li>
639<li>The code generator now supports a mode where it attempts to preserve the
640 order of instructions in the input code. This is important for source that
641 is hand scheduled and extremely sensitive to scheduling. It is compatible
642 with the GCC <tt>-fno-schedule-insns</tt> option.</li>
643<li>The target-independent code generator now supports generating code with
644 arbitrary numbers of result values. Returning more values than was
645 previously supported is handled by returning through a hidden pointer. In
646 2.7, only the X86 and XCore targets have adopted support for this
647 though.</li>
648<li>The code generator now supports generating code that follows the
649 <a href="LangRef.html#callingconv">Glasgow Haskell Compiler Calling
650 Convention</a> and ABI.</li>
651<li>The "<a href="CodeGenerator.html#selectiondag_select">DAG instruction
652 selection</a>" phase of the code generator has been largely rewritten for
653 2.7. Previously, tblgen spit out tons of C++ code which was compiled and
654 linked into the target to do the pattern matching, now it emits a much
655 smaller table which is read by the target-independent code. The primary
656 advantages of this approach is that the size and compile time of various
657 targets is much improved. The X86 code generator shrunk by 1.5MB of code,
658 for example.</li>
659<li>Almost the entire code generator has switched to emitting code through the
660 MC interfaces instead of printing textually to the .s file. This led to a
661 number of cleanups and speedups. In 2.7, debug an exception handling
662 information does not go through MC yet.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]663</ul>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]664</div>
665
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]666<!--=========================================================================-->
667<div class="doc_subsection">
668<a name="x86">X86-32 and X86-64 Target Improvements</a>
669</div>
670
671<div class="doc_text">
672<p>New features of the X86 target include:
673</p>
674
675<ul>
Chris Lattnera668b452010-04-21 06:42:24 +0000[diff] [blame]676<li>The X86 backend now optimizes tails calls much more aggressively for
677 functions that use the standard C calling convention.</li>
678<li>The X86 backend now models scalar SSE registers as subregs of the SSE vector
679 registers, making the code generator more aggressive in cases where scalars
680 and vector types are mixed.</li>
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]681
Chris Lattnera668b452010-04-21 06:42:24 +0000[diff] [blame]682<li>PostRA scheduler for X86? FIXME: is this on by default in 2.7?</li>
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]683
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]684</ul>
685
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]686</div>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]687
688<!--=========================================================================-->
689<div class="doc_subsection">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]690<a name="ARM">ARM Target Improvements</a>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]691</div>
692
693<div class="doc_text">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]694<p>New features of the ARM target include:
695</p>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]696
697<ul>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]698
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]699<li>The ARM backend now generates instructions in unified assembly syntax.</li>
700
701<li>llvm-gcc now has complete support for the ARM v7 NEON instruction set. This
702 support differs slightly from the GCC implementation. Please see the
703 <a
704href="http://blog.llvm.org/2010/04/arm-advanced-simd-neon-intrinsics-and.html">
705 ARM Advanced SIMD (NEON) Intrinsics and Types in LLVM Blog Post</a> for
706 helpful information if migrating code from GCC to LLVM-GCC.</li>
707
708<li>The ARM and Thumb code generators now using register scavenging for stack
709 object address materialization.(FIXME: WHAT BENEFIT DOES THIS PROVIDE?)</li>
710
711<li>The ARM backend now has good support for ARMv4 targets, and has been tested
712 on StrongARM hardware. Previously, LLVM only supported ARMv4T and
713 newer chips.</li>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]714</ul>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]715
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]716
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]717</div>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]718
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]719<!--=========================================================================-->
720<div class="doc_subsection">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]721<a name="newapis">New Useful APIs</a>
722</div>
723
724<div class="doc_text">
725
726<p>This release includes a number of new APIs that are used internally, which
727 may also be useful for external clients.
728</p>
729
730<ul>
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]731<li>The optimizer uses the new CodeMetrics class to measure the size of code.
732 Various passes that use thing (like the inliner, loop unswitcher, etc) all
733 use this to make more accurate estimates of the code size impact of various
734 optimizations.</li>
735<li>A new <a href="http://llvm.org/doxygen/InstructionSimplify_8h-source.html">
736 llvm/Analysis/InstructionSimplify.h</a> interface available for doing
737 symbolic simplification of instructions (e.g. <tt>a+0</tt> -&gt; <tt>a</tt>)
738 without requiring the instruction to exist. This centralizes a lot of
739 ad-hoc symbolic manipulation code scattered in various passes.</li>
740<li>The optimizer now uses a new <a
741 href="http://llvm.org/doxygen/SSAUpdater_8h-source.html">SSAUpdater</a>
742 class which efficiently supports
743 doing unstructured SSA update operations. This centralized a bunch of code
744 scattered through various passes (e.g. jump threading, lcssa, loop rotate,
745 etc) for doing this sort of thing. The code generator has an similar
746 <a href="http://llvm.org/doxygen/MachineSSAUpdater_8h-source.html">
747 MachineSSAUpdater</a> class.</li>
748<li>The <a href="http://llvm.org/doxygen/Regex_8h-source.html">
749 llvm/Support/Regex.h</a> header exposes a platform independent regular
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]750 expression API. Building on this, the <a
751 href="TestingGuide.html#FileCheck">FileCheck</a> utility now supports
752 regular exressions.</li>
753<li>raw_ostream now supports a circular "debug stream" accessed with "dbgs()".
754 By default, this stream works the same way as "errs()", but if you pass
755 <tt>-debug-buffer-size=1000</tt> to opt, the debug stream is capped to a
756 fixed sized circular buffer and the output is printed at the end of the
757 program's execution. This is helpful if you have a long lived compiler
758 process and you're interested in seeing snapshots in time.</li>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]759</ul>
760
761
762</div>
763
764<!--=========================================================================-->
765<div class="doc_subsection">
766<a name="otherimprovements">Other Improvements and New Features</a>
767</div>
768
769<div class="doc_text">
770<p>Other miscellaneous features include:</p>
771
772<ul>
Chris Lattner1dcca8b2010-04-21 06:23:40 +0000[diff] [blame]773<li>You can now build LLVM as a big dynamic library (e.g. "libllvm2.7.so"). To
774 get this, configure LLVM with the --enable-shared option.</li>
775
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]776<li>LLVM command line tools now overwrite their output by default, before they
777 would only do this with -f. This makes them more convenient to use, and
778 behave more like standard unix tools.</li>
779
780<li>The opt and llc tools now autodetect whether their input is a .ll or .bc
781 file, and automatically do the right thing. This means you don't need to
782 explicitly use the llvm-as tool for most things.</li>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]783</ul>
784
785</div>
786
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]787
788<!--=========================================================================-->
789<div class="doc_subsection">
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]790<a name="changes">Major Changes and Removed Features</a>
791</div>
792
793<div class="doc_text">
794
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]795<p>If you're already an LLVM user or developer with out-of-tree changes based
Jeffrey Yasskin0830b972010-01-28 01:14:43 +0000[diff] [blame]796on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]797from the previous release.</p>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]798
799<ul>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]800
801<li>
802The Andersen's alias analysis ("anders-aa") pass, the Predicate Simplifier
803("predsimplify") pass, the LoopVR pass, the GVNPRE pass, and the random sampling
804profiling ("rsprofiling") passes have all been removed. They were not being
805actively maintained and had substantial problems. If you are interested in
806these components, you are welcome to ressurect them from SVN, fix the
807correctness problems, and resubmit them to mainline.</li>
808
809<li>LLVM now defaults to building most libraries with RTTI turned off, providing
810a code size reduction. Packagers who are interested in building LLVM to support
811plugins that require RTTI information should build with "make REQUIRE_RTTI=1"
812and should read the new <a href="Packaging.html">Advice on Packaging LLVM</a>
813document.</li>
814
Jeffrey Yasskin914050b2010-02-09 23:03:44 +0000[diff] [blame]815<li>The LLVM interpreter now defaults to <em>not</em> using <tt>libffi</tt> even
816if you have it installed. This makes it more likely that an LLVM built on one
817system will work when copied to a similar system. To use <tt>libffi</tt>,
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]818configure with <tt>--enable-libffi</tt>.</li>
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]819
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]820<li>Debug information uses a completely different representation, an LLVM 2.6
821.bc file should work with LLVM 2.7, but debug info won't come forward.</li>
822
823<li>The LLVM 2.6 (and earlier) "malloc" and "free" instructions got removed,
824 along with LowerAllocations pass. Now you should just use a call to the
825 malloc and free functions in libc. These calls are optimized as well as
826 the old instructions were.</li>
827</ul>
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]828
829<p>In addition, many APIs have changed in this release. Some of the major LLVM
830API changes are:</p>
831
832<ul>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]833<li>Just about everything has been converted to use raw_ostream instead of
834 std::ostream.</li>
835<li>llvm/ADT/iterator.h has been removed, just use &lt;iterator&gt;
836 instead.</li>
837<li>The Streams.h file and "DOUT" got removed, use "DEBUG(errs() &lt;&lt; ...);"
838 instead.</li>
Jeffrey Yasskin4a8b1da2010-01-28 01:41:20 +0000[diff] [blame]839<li><tt>ModuleProvider</tt> has been <a
840href="http://llvm.org/viewvc/llvm-project?view=rev&revision=94686">removed</a>
841and its methods moved to <tt>Module</tt> and <tt>GlobalValue</tt>.
842Most clients can remove uses of <tt>ExistingModuleProvider</tt>,
843replace <tt>getBitcodeModuleProvider</tt> with
844<tt>getLazyBitcodeModule</tt>, and pass their <tt>Module</tt> to
845functions that used to accept <tt>ModuleProvider</tt>. Clients who
846wrote their own <tt>ModuleProvider</tt>s will need to derive from
847<tt>GVMaterializer</tt> instead and use
848<tt>Module::setMaterializer</tt> to attach it to a
849<tt>Module</tt>.</li>
850
851<li><tt>GhostLinkage</tt> has given up the ghost.
852<tt>GlobalValue</tt>s that have not yet been read from their backing
853storage have the same linkage they will have after being read in.
854Clients must replace calls to
855<tt>GlobalValue::hasNotBeenReadFromBitcode</tt> with
856<tt>GlobalValue::isMaterializable</tt>.</li>
Daniel Dunbar1e96fca2010-02-10 04:09:52 +0000[diff] [blame]857
Daniel Dunbar3e255da2010-02-14 01:47:19 +0000[diff] [blame]858<li>The <tt>llvm/Support/DataTypes.h</tt> header has moved
859to <tt>llvm/System/DataTypes.h</tt>.</li>
860
Duncan Sands80c430a2010-02-17 17:20:17 +0000[diff] [blame]861<li>The <tt>isInteger</tt>, <tt>isIntOrIntVector</tt>, <tt>isFloatingPoint</tt>,
862<tt>isFPOrFPVector</tt> and <tt>isFPOrFPVector</tt> methods have been renamed
863<tt>isIntegerTy</tt>, <tt>isIntOrIntVectorTy</tt>, <tt>isFloatingPointTy</tt>,
864<tt>isFPOrFPVectorTy</tt> and <tt>isFPOrFPVectorTy</tt> respectively.</li>
Devang Pateldbf83832008-10-14 20:03:43 +0000[diff] [blame]865</ul>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]866
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]867</div>
868
869
870
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]871<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]872<div class="doc_section">
873 <a name="portability">Portability and Supported Platforms</a>
874</div>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]875<!-- *********************************************************************** -->
876
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]877<div class="doc_text">
878
John Criswell64307722004-12-08 20:35:47 +0000[diff] [blame]879<p>LLVM is known to work on the following platforms:</p>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]880
881<ul>
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]882<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]883 Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like
884 systems).</li>
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]885<li>PowerPC and X86-based Mac OS X systems, running 10.4 and above in 32-bit
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]886 and 64-bit modes.</li>
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]887<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]888<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
889 support is available for native builds with Visual C++).</li>
Chris Lattner51948622009-10-16 16:30:58 +0000[diff] [blame]890<li>Sun x86 and AMD64 machines running Solaris 10, OpenSolaris 0906.</li>
John Criswelld5234922005-05-13 20:28:15 +0000[diff] [blame]891<li>Alpha-based machines running Debian GNU/Linux.</li>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]892</ul>
893
Chris Lattner618a99f2008-06-05 06:57:39 +0000[diff] [blame]894<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
Brian Gaekee3e557e2004-05-09 05:28:35 +0000[diff] [blame]895to the machine and operating system on which it is built. However, minor
896porting may be required to get LLVM to work on new platforms. We welcome your
897portability patches and reports of successful builds or error messages.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]898
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]899</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]900
901<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]902<div class="doc_section">
903 <a name="knownproblems">Known Problems</a>
904</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]905<!-- *********************************************************************** -->
906
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]907<div class="doc_text">
908
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]909<p>This section contains significant known problems with the LLVM system,
Chris Lattner2a092392008-11-10 05:40:34 +0000[diff] [blame]910listed by component. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]911href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]912there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]913
Chris Lattner6aba4862010-03-17 17:25:49 +0000[diff] [blame]914<ul>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]915<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
916using the stock GCC 3.x.x series 'out the box',
Chris Lattner6e41c792009-11-03 21:50:09 +0000[diff] [blame]917See: <a href="GettingStarted.html#brokengcc">Broken versions of GCC and other tools</a>.
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]918However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
919for x86/x86-64 has been made available from the third party AuroraUX Project
920that has been meticulously tested for bootstrapping LLVM &amp; Clang.</li>
921</ul>
922
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]923</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]924
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]925<!-- ======================================================================= -->
926<div class="doc_subsection">
927 <a name="experimental">Experimental features included with this release</a>
928</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]929
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]930<div class="doc_text">
931
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]932<p>The following components of this LLVM release are either untested, known to
933be broken or unreliable, or are in early development. These components should
934not be relied on, and bugs should not be filed against them, but they may be
935useful 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]936components, please contact us on the <a
937href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]938
939<ul>
Wesley Peck3aa84e52010-03-18 14:31:30 +0000[diff] [blame]940<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
941 backends are experimental.</li>
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]942<li><tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
Chris Lattner0b1c9a52010-03-17 04:41:49 +0000[diff] [blame]943 supported value for this option. The MachO writer is experimental, and
944 works much better in mainline SVN.</li>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]945</ul>
946
947</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]948
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]949<!-- ======================================================================= -->
950<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]951 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]952</div>
953
954<div class="doc_text">
955
956<ul>
Anton Korobeynikov486c7d32008-06-08 10:24:13 +0000[diff] [blame]957 <li>The X86 backend does not yet support
958 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
959 floating point stack</a>. It supports the 'f' and 't' constraints, but not
960 'u'.</li>
Chris Lattnerb076b002008-06-08 21:19:07 +0000[diff] [blame]961 <li>The X86 backend generates inefficient floating point code when configured
962 to generate code for systems that don't have SSE2.</li>
Duncan Sands0bc15262008-06-08 19:38:43 +0000[diff] [blame]963 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]964 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]965 runtime currently due to lack of support for the 'u' inline assembly
966 constraint and for X87 floating point inline assembly.</li>
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]967 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]968 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]969 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]970</ul>
971
972</div>
973
974<!-- ======================================================================= -->
975<div class="doc_subsection">
976 <a name="ppc-be">Known problems with the PowerPC back-end</a>
977</div>
978
979<div class="doc_text">
980
981<ul>
Nicolas Geoffray77d99502007-05-15 09:21:28 +0000[diff] [blame]982<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]983compilation, and lacks support for debug information.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]984</ul>
985
986</div>
987
988<!-- ======================================================================= -->
989<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]990 <a name="arm-be">Known problems with the ARM back-end</a>
991</div>
992
993<div class="doc_text">
994
995<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]996<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands47fc0a22007-09-26 15:59:54 +0000[diff] [blame]997processors, thumb programs can crash or produce wrong
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]998results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]999<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]1000</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]1001</ul>
1002
1003</div>
1004
1005<!-- ======================================================================= -->
1006<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1007 <a name="sparc-be">Known problems with the SPARC back-end</a>
1008</div>
1009
1010<div class="doc_text">
1011
1012<ul>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]1013<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]1014 support the 64-bit SPARC ABI (-m64).</li>
1015</ul>
1016
1017</div>
1018
1019<!-- ======================================================================= -->
1020<div class="doc_subsection">
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]1021 <a name="mips-be">Known problems with the MIPS back-end</a>
1022</div>
1023
1024<div class="doc_text">
1025
1026<ul>
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]1027<li>64-bit MIPS targets are not supported yet.</li>
1028</ul>
1029
1030</div>
1031
1032<!-- ======================================================================= -->
1033<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1034 <a name="alpha-be">Known problems with the Alpha back-end</a>
1035</div>
1036
1037<div class="doc_text">
1038
1039<ul>
1040
1041<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
1042appropriate nops inserted to ensure restartability.</li>
1043
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]1044</ul>
1045</div>
1046
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1047<!-- ======================================================================= -->
1048<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]1049 <a name="c-be">Known problems with the C back-end</a>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1050</div>
1051
1052<div class="doc_text">
1053
1054<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]1055<li><a href="http://llvm.org/PR802">The C backend has only basic support for
1056 inline assembly code</a>.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000[diff] [blame]1057<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
1058 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif75b2f762009-03-02 12:02:51 +0000[diff] [blame]1059 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandse09506a2008-02-10 13:40:55 +0000[diff] [blame]1060<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands3aa36732009-02-25 11:51:54 +0000[diff] [blame]1061<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]1062</ul>
1063
1064</div>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]1065
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1066
1067<!-- ======================================================================= -->
1068<div class="doc_subsection">
Chris Lattner0b1c9a52010-03-17 04:41:49 +0000[diff] [blame]1069 <a name="c-fe">Known problems with the llvm-gcc C and C++ front-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1070</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000[diff] [blame]1071
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1072<div class="doc_text">
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]1073
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]1074<p>The only major language feature of GCC not supported by llvm-gcc is
1075 the <tt>__builtin_apply</tt> family of builtins. However, some extensions
1076 are only supported on some targets. For example, trampolines are only
Duncan Sands56448462008-06-08 20:18:35 +0000[diff] [blame]1077 supported on some targets (these are used when you take the address of a
1078 nested function).</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1079
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1080</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1081
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1082<!-- ======================================================================= -->
1083<div class="doc_subsection">
Chris Lattner7292fb12008-10-30 03:58:13 +0000[diff] [blame]1084 <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
1085</div>
1086
1087<div class="doc_text">
Gabor Greife5f9d672008-11-04 21:50:59 +0000[diff] [blame]1088<ul>
Chris Lattner7292fb12008-10-30 03:58:13 +0000[diff] [blame]1089<li>Fortran support generally works, but there are still several unresolved bugs
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]1090 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
1091 tools/gfortran component for details.</li>
Gabor Greife5f9d672008-11-04 21:50:59 +0000[diff] [blame]1092</ul>
Chris Lattner7292fb12008-10-30 03:58:13 +0000[diff] [blame]1093</div>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1094
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1095<!-- ======================================================================= -->
1096<div class="doc_subsection">
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]1097 <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1098</div>
1099
1100<div class="doc_text">
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]1101The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
1102technology, and problems should be expected.
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1103<ul>
Duncan Sands56448462008-06-08 20:18:35 +0000[diff] [blame]1104<li>The Ada front-end currently only builds on X86-32. This is mainly due
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]1105to lack of trampoline support (pointers to nested functions) on other platforms.
1106However, 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]1107which does support trampolines.</li>
1108<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]1109This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
1110exception handling, which is used internally by the compiler.
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]1111Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
Duncan Sandsaef747f2008-10-13 17:27:23 +0000[diff] [blame]1112<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
1113and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sandsd34bf762009-02-25 11:59:06 +0000[diff] [blame]1114(c380004 also fails with gcc-4.2 mainline).
1115If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
1116causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sands2dbb00e2009-03-02 16:35:57 +0000[diff] [blame]1117<li>Some GCC specific Ada tests continue to crash the compiler.</li>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]1118<li>The <tt>-E</tt> binder option (exception backtraces)
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1119<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]1120crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1121<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
1122or finish at a non-byte offset</a> in a record. Workaround: do not pack records
1123or use representation clauses that result in a field of a non-discrete type
1124starting or finishing in the middle of a byte.</li>
Chris Lattnerb076b002008-06-08 21:19:07 +0000[diff] [blame]1125<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
1126'main' as generated by the Ada binder to be invalid</a>.
1127Workaround: hand edit the file to use pointers for <tt>argv</tt> and
1128<tt>envp</tt> rather than integers.</li>
1129<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
1130ignored</a>.</li>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]1131</ul>
1132</div>
1133
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1134<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1135<div class="doc_section">
1136 <a name="additionalinfo">Additional Information</a>
1137</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1138<!-- *********************************************************************** -->
1139
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1140<div class="doc_text">
1141
Chris Lattnercb5596d2005-05-16 17:13:10 +0000[diff] [blame]1142<p>A wide variety of additional information is available on the <a
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]1143href="http://llvm.org">LLVM web page</a>, in particular in the <a
1144href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]1145contains versions of the API documentation which is up-to-date with the
1146Subversion version of the source code.
Misha Brukman96158092005-03-30 19:14:24 +0000[diff] [blame]1147You can access versions of these documents specific to this release by going
1148into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1149
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1150<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]1151us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]1152lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1153
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1154</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1155
1156<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1157
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1158<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1159<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000[diff] [blame]1160 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]1161 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1162 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]1163 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]1164
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]1165 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1166 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]1167</address>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]1168
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1169</body>
1170</html>