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gerrit-public.fairphone.software / toolchain / llvm-project / 086d2694133f728cf70c0cb3af40145b0333cf9c / . / llvm / docs / ReleaseNotes.html
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Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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4<head>
Reid Spencere4190fa2004-11-18 18:38:58 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]6 <link rel="stylesheet" href="llvm.css" type="text/css">
Dan Gohman62af9d22010-05-03 23:51:05 +0000[diff] [blame]7 <title>LLVM 2.8 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
Dan Gohman62af9d22010-05-03 23:51:05 +0000[diff] [blame]11<div class="doc_title">LLVM 2.8 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"
Gabor Greif27b166352010-04-22 10:21:43 +0000[diff] [blame]14 width="136" height="136" alt="LLVM Dragon Logo">
Chris Lattnerc871bac2010-03-17 04:02:39 +0000[diff] [blame]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>
Dan Gohman62af9d22010-05-03 23:51:05 +0000[diff] [blame]19 <li><a href="#externalproj">External Projects Using LLVM 2.8</a></li>
20 <li><a href="#whatsnew">What's New in LLVM 2.8?</a></li>
Chris Lattner77a51732004-04-30 22:17:12 +0000[diff] [blame]21 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Dan Gohmanad888912008-10-14 16:23:02 +0000[diff] [blame]22 <li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]23 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]24</ol>
25
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]26<div class="doc_author">
Dan Gohmanad888912008-10-14 16:23:02 +0000[diff] [blame]27 <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]28</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]29
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]30<!--
Chris Lattner656db162010-04-22 05:41:35 +0000[diff] [blame]31<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]32release.<br>
33You may prefer the
Dan Gohman62af9d22010-05-03 23:51:05 +0000[diff] [blame]34<a href="http://llvm.org/releases/2.7/docs/ReleaseNotes.html">LLVM 2.7
35Release Notes</a>.</h1>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]36-->
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
Dan Gohman3b763f42010-05-03 23:52:21 +0000[diff] [blame]47Infrastructure, release 2.8. 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 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 Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]78 llvm.dbg.value: variable debug info for optimized code
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]79 loop dependence analysis
Chris Lattnerbd244042010-08-28 16:33:36 +0000[diff] [blame]80 TBAA
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]81 CorrelatedValuePropagation
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]82 -->
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]83
84 <!-- Announcement, lldb, libc++ -->
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
Daniel Dunbarc11b40f2008-10-14 23:25:09 +0000[diff] [blame]122<ul>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]123<li>Surely these guys have done something</li>
Bill Wendling87adbe42009-03-02 04:28:18 +0000[diff] [blame]124</ul>
Chris Lattner44c09cd2008-10-13 18:11:54 +0000[diff] [blame]125</div>
126
127<!--=========================================================================-->
128<div class="doc_subsection">
129<a name="clangsa">Clang Static Analyzer</a>
130</div>
131
132<div class="doc_text">
133
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]134<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a>
135 project is an effort to use static source code analysis techniques to
136 automatically find bugs in C and Objective-C programs (and hopefully <a
137 href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the
138 future</a>!). The tool is very good at finding bugs that occur on specific
139 paths through code, such as on error conditions.</p>
Chris Lattnerbcffa5a2008-10-14 00:52:49 +0000[diff] [blame]140
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]141<p>In the LLVM 2.8 time-frame,
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]142</p>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]143
144</div>
145
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]146<!--=========================================================================-->
147<div class="doc_subsection">
Nicolas Geoffraye5ec9322008-10-14 19:23:04 +0000[diff] [blame]148<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]149</div>
150
151<div class="doc_text">
152<p>
Nicolas Geoffraye5ec9322008-10-14 19:23:04 +0000[diff] [blame]153The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]154a JVM and a CLI Virtual Machine (Microsoft .NET is an
155implementation of the CLI) using LLVM for static and just-in-time
156compilation.</p>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]157
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]158<p>With the release of LLVM 2.8, ...</p>
Chris Lattnerf5cd9862008-10-13 18:01:01 +0000[diff] [blame]159
160</div>
161
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]162
163<!--=========================================================================-->
164<div class="doc_subsection">
165<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
166</div>
167
168<div class="doc_text">
169<p>
170The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
171is a simple library that provides an implementation of the low-level
172target-specific hooks required by code generation and other runtime components.
173For example, when compiling for a 32-bit target, converting a double to a 64-bit
174unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
175function. The compiler-rt library provides highly optimized implementations of
176this and other low-level routines (some are 3x faster than the equivalent
177libgcc routines).</p>
178
179<p>
180All of the code in the compiler-rt project is available under the standard LLVM
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]181License, a "BSD-style" license. New in LLVM 2.8:
182
183Soft float support
184</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]185
186</div>
187
188<!--=========================================================================-->
189<div class="doc_subsection">
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]190<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]191</div>
192
193<div class="doc_text">
194<p>
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]195<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
196gcc-4.5. Unlike llvm-gcc, which makes many intrusive changes to the underlying
197gcc-4.2 code, dragonegg in theory does not require any gcc-4.5 modifications
198whatsoever (currently one small patch is needed). This is thanks to the new
199<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>, which
200makes it possible to modify the behaviour of gcc at runtime by loading a plugin,
201which is nothing more than a dynamic library which conforms to the gcc plugin
202interface. DragonEgg is a gcc plugin that causes the LLVM optimizers to be run
203instead of the gcc optimizers, and the LLVM code generators instead of the gcc
204code generators, just like llvm-gcc. To use it, you add
205"-fplugin=path/dragonegg.so" to the gcc-4.5 command line, and gcc-4.5 magically
206becomes llvm-gcc-4.5!
207</p>
208
209<p>
210DragonEgg is still a work in progress. Currently C works very well, while C++,
211Ada and Fortran work fairly well. All other languages either don't work at all,
212or 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]213supported, and only on linux and darwin (darwin needs an additional gcc patch).
Duncan Sands92452b92010-04-02 09:23:15 +0000[diff] [blame]214</p>
215
216<p>
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]2172.8 status here.
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]218</p>
219
220</div>
221
222
223<!--=========================================================================-->
224<div class="doc_subsection">
225<a name="mc">llvm-mc: Machine Code Toolkit</a>
226</div>
227
228<div class="doc_text">
229<p>
Chris Lattner2284b6a2010-04-22 06:38:11 +0000[diff] [blame]230The LLVM Machine Code (aka MC) sub-project of LLVM was created to solve a number
231of problems in the realm of assembly, disassembly, object file format handling,
232and a number of other related areas that CPU instruction-set level tools work
233in. It is a sub-project of LLVM which provides it with a number of advantages
234over other compilers that do not have tightly integrated assembly-level tools.
235For a gentle introduction, please see the <a
236href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
237LLVM MC Project Blog Post</a>.
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]238</p>
239
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]240<p>2.8 status here</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]241</div>
242
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]243<!--=========================================================================-->
244<div class="doc_subsection">
245<a name="lldb">LLDB: Low Level Debugger</a>
246</div>
247
248<div class="doc_text">
249<p>
250<a href="http://lldb.llvm.org/">LLDB</a> is</p>
251
252<p>
253</p>
254
255<p>
2562.8 status here.
257</p>
258
259</div>
260
261<!--=========================================================================-->
262<div class="doc_subsection">
263<a name="libc++">libc++: C++ Standard Library</a>
264</div>
265
266<div class="doc_text">
267<p>
268<a href="http://libc++.llvm.org/">libc++</a> is</p>
269
270<p>
271</p>
272
273<p>
2742.8 status here.
275</p>
276
277</div>
278
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]279
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]280<!-- *********************************************************************** -->
281<div class="doc_section">
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]282 <a name="externalproj">External Open Source Projects Using LLVM 2.8</a>
Chris Lattner53e06f92009-02-26 22:33:38 +0000[diff] [blame]283</div>
284<!-- *********************************************************************** -->
285
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]286<div class="doc_text">
287
288<p>An exciting aspect of LLVM is that it is used as an enabling technology for
289 a lot of other language and tools projects. This section lists some of the
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]290 projects that have already been updated to work with LLVM 2.8.</p>
Chris Lattnerdf85c892010-04-26 17:38:10 +0000[diff] [blame]291</div>
292
Chris Lattner64694df2010-04-22 21:34:16 +0000[diff] [blame]293
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]294<!-- *********************************************************************** -->
295<div class="doc_section">
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]296 <a name="whatsnew">What's New in LLVM 2.8?</a>
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]297</div>
298<!-- *********************************************************************** -->
299
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]300<div class="doc_text">
301
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]302<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]303minor improvements. Some of the major improvements and new features are listed
304in this section.
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]305</p>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]306
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]307</div>
308
309<!--=========================================================================-->
310<div class="doc_subsection">
311<a name="orgchanges">LLVM Community Changes</a>
312</div>
313
314<div class="doc_text">
315
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]316<p>In addition to changes to the code, between LLVM 2.7 and 2.8, a number of
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]317organization changes have happened:
318</p>
319
320<ul>
Chris Lattner342f9572010-09-29 05:30:03 +0000[diff] [blame]321<li>libc++ and lldb are new</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]322</ul>
Chris Lattnerb7bc2aa2008-06-08 22:59:35 +0000[diff] [blame]323</div>
324
Chris Lattnerc75fd522008-06-08 21:58:17 +0000[diff] [blame]325<!--=========================================================================-->
Chris Lattner625a3d82008-06-08 21:34:41 +0000[diff] [blame]326<div class="doc_subsection">
Chris Lattnercdc44ed2008-02-06 18:00:06 +0000[diff] [blame]327<a name="majorfeatures">Major New Features</a>
328</div>
329
330<div class="doc_text">
331
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]332<p>LLVM 2.8 includes several major new capabilities:</p>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]333
334<ul>
Chris Lattner8c26cee2010-09-05 20:49:45 +0000[diff] [blame]335<li>atomic lowering pass.</li>
336<li>RegionInfo pass: opt -regions analyze" or "opt -view-regions".
337<!-- Tobias Grosser --></li>
338<li>ARMGlobalMerge: <!-- Anton --> </li>
Chris Lattner8128ca12010-09-06 19:14:40 +0000[diff] [blame]339<li>llvm-diff</li>
Chris Lattner458e79f2008-02-10 08:18:42 +0000[diff] [blame]340</ul>
Chris Lattner10a3cc42010-03-17 06:41:58 +0000[diff] [blame]341
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]342</div>
343
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]344<!--=========================================================================-->
345<div class="doc_subsection">
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]346<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]347</div>
348
349<div class="doc_text">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]350<p>LLVM IR has several new features for better support of new targets and that
351expose new optimization opportunities:</p>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]352
Chris Lattnerb7112222008-06-05 06:25:56 +0000[diff] [blame]353<ul>
Gabor Greif4b17e652010-07-21 10:20:08 +0000[diff] [blame]354
355<li>LLVM 2.8 changes the internal order of operands in <a
356 href="http://llvm.org/doxygen/classllvm_1_1InvokeInst.html"><tt>InvokeInst</tt></a>
357 and <a href="http://llvm.org/doxygen/classllvm_1_1CallInst.html"><tt>CallInst</tt></a>.
358 To be portable across releases, resort to <tt>CallSite</tt> and the
Gabor Greif930894f2010-07-21 10:22:41 +0000[diff] [blame]359 high-level accessors, such as <tt>getCalledValue</tt> and <tt>setUnwindDest</tt>.
Gabor Greif4b17e652010-07-21 10:20:08 +0000[diff] [blame]360</li>
Gabor Greifed79dcb2010-07-26 18:48:07 +0000[diff] [blame]361<li>
362 You can no longer pass use_iterators directly to cast<> (and similar), because
363 these routines tend to perform costly dereference operations more than once. You
364 have to dereference the iterators yourself and pass them in.
365</li>
Torok Edwine6f478f2010-08-04 12:43:22 +0000[diff] [blame]366<li>
367 llvm.memcpy.*, llvm.memset.*, llvm.memmove.* (and possibly other?) intrinsics
368 take an extra parameter now (i1 isVolatile), totaling 5 parameters.
369 If you were creating these intrinsic calls and prototypes yourself (as opposed
370 to using Intrinsic::getDeclaration), you can use UpgradeIntrinsicFunction/UpgradeIntrinsicCall
371 to be portable accross releases.
372 Note that you cannot use Intrinsic::getDeclaration() in a backwards compatible
373 way (needs 2/3 types now, in 2.7 it needed just 1).
374</li>
375<li>
376 SetCurrentDebugLocation takes a DebugLoc now instead of a MDNode.
377 Change your code to use
378 SetCurrentDebugLocation(DebugLoc::getFromDILocation(...)).
379</li>
380<li>
381 VISIBILITY_HIDDEN is gone.
382</li>
383<li>
Owen Andersonf16eb372010-08-04 18:27:08 +0000[diff] [blame]384 The <tt>RegisterPass</tt> and <tt>RegisterAnalysisGroup</tt> templates are
385 considered deprecated, but continue to function in LLVM 2.8. Clients are
386 strongly advised to use the upcoming <tt>INITIALIZE_PASS()</tt> and
387 <tt>INITIALIZE_AG_PASS()</tt> macros instead.
388<li>
Torok Edwine6f478f2010-08-04 12:43:22 +0000[diff] [blame]389 SMDiagnostic takes different parameters now. //FIXME: how to upgrade?
390</li>
391<li>
Duncan Sands1b6744a2010-08-30 10:57:54 +0000[diff] [blame]392 The constructor for the Triple class no longer tries to understand odd triple
393 specifications. Frontends should ensure that they only pass valid triples to
394 LLVM. The Triple::normalize utility method has been added to help front-ends
395 deal with funky triples.
396<li>
Torok Edwine6f478f2010-08-04 12:43:22 +0000[diff] [blame]397 Some APIs got renamed:
398 <ul>
399 <li>llvm_report_error -&gt; report_fatal_error</li>
400 <li>llvm_install_error_handler -&gt; install_fatal_error_handler</li>
401 <li>llvm::DwarfExceptionHandling -&gt; llvm::JITExceptionHandling</li>
402 </ul>
403</li>
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]404</ul>
Mikhail Glushenkov024f7cf2008-10-13 02:08:34 +0000[diff] [blame]405
Chris Lattnerdd6acc02008-02-10 08:17:19 +0000[diff] [blame]406</div>
407
408<!--=========================================================================-->
409<div class="doc_subsection">
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]410<a name="optimizer">Optimizer Improvements</a>
411</div>
412
413<div class="doc_text">
414
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]415<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]416release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner2b8a52e2008-02-10 07:46:44 +0000[diff] [blame]417
418<ul>
419
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]420<li></li>
Chris Lattnera668b452010-04-21 06:42:24 +0000[diff] [blame]421
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]422</ul>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]423
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]424</div>
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]425
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]426
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]427<!--=========================================================================-->
428<div class="doc_subsection">
429<a name="executionengine">Interpreter and JIT Improvements</a>
430</div>
Chris Lattner25879d72008-10-13 21:50:36 +0000[diff] [blame]431
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]432<div class="doc_text">
433
434<ul>
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]435<li></li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]436
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]437</ul>
438
439</div>
440
441<!--=========================================================================-->
442<div class="doc_subsection">
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]443<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]444</div>
445
446<div class="doc_text">
447
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]448<p>We have put a significant amount of work into the code generator
449infrastructure, which allows us to implement more aggressive algorithms and make
450it run faster:</p>
Chris Lattner7795ea92008-06-08 02:45:07 +0000[diff] [blame]451
452<ul>
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]453<li>MachO writer works.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]454</ul>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]455</div>
456
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]457<!--=========================================================================-->
458<div class="doc_subsection">
459<a name="x86">X86-32 and X86-64 Target Improvements</a>
460</div>
461
462<div class="doc_text">
463<p>New features of the X86 target include:
464</p>
465
466<ul>
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]467<li>The X86 backend now supports holding X87 floating point stack values
468 in registers across basic blocks, dramatically improving performance of code
469 that uses long double, and when targetting CPUs that don't support SSE.</li>
Chris Lattnerd434bfb2009-03-02 03:24:11 +0000[diff] [blame]470
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]471</ul>
472
Chris Lattnerd1094e02009-03-02 02:37:32 +0000[diff] [blame]473</div>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]474
475<!--=========================================================================-->
476<div class="doc_subsection">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]477<a name="ARM">ARM Target Improvements</a>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]478</div>
479
480<div class="doc_text">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]481<p>New features of the ARM target include:
482</p>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]483
484<ul>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]485
Bob Wilson46d65802010-09-13 17:37:55 +0000[diff] [blame]486<li>
487 All of the NEON load and store intrinsics (llvm.arm.neon.vld* and
488 llvm.arm.neon.vst*) take an extra parameter to specify the alignment in bytes
489 of the memory being accessed.
490</li>
491<li>
492 The llvm.arm.neon.vaba intrinsic (vector absolute difference and
493 accumulate) has been removed. This operation is now represented using
494 the llvm.arm.neon.vabd intrinsic (vector absolute difference) followed by a
495 vector add.
Bob Wilsone44f2982010-09-13 17:39:35 +0000[diff] [blame]496</li>
Bob Wilson46d65802010-09-13 17:37:55 +0000[diff] [blame]497<li>
498 The llvm.arm.neon.vabdl and llvm.arm.neon.vabal intrinsics (lengthening
499 vector absolute difference with and without accumlation) have been removed.
500 They are represented using the llvm.arm.neon.vabd intrinsic (vector absolute
501 difference) followed by a vector zero-extend operation, and for vabal,
502 a vector add.
503</li>
504<li>
505 The llvm.arm.neon.vmovn intrinsic has been removed. Calls of this intrinsic
506 are now replaced by vector truncate operations.
507</li>
508<li>
509 The llvm.arm.neon.vmovls and llvm.arm.neon.vmovlu intrinsics have been
510 removed. They are now represented as vector sign-extend (vmovls) and
511 zero-extend (vmovlu) operations.
512</li>
513<li>
514 The llvm.arm.neon.vaddl*, llvm.arm.neon.vaddw*, llvm.arm.neon.vsubl*, and
515 llvm.arm.neon.vsubw* intrinsics (lengthening vector add and subtract) have
516 been removed. They are replaced by vector add and vector subtract operations
517 where one (vaddw, vsubw) or both (vaddl, vsubl) of the operands are either
518 sign-extended or zero-extended.
519</li>
520<li>
521 The llvm.arm.neon.vmulls, llvm.arm.neon.vmullu, llvm.arm.neon.vmlal*, and
522 llvm.arm.neon.vmlsl* intrinsics (lengthening vector multiply with and without
523 accumulation and subtraction) have been removed. These operations are now
524 represented as vector multiplications where the operands are either
525 sign-extended or zero-extended, followed by a vector add for vmlal or a
526 vector subtract for vmlsl. Note that the polynomial vector multiply
527 intrinsic, llvm.arm.neon.vmullp, remains unchanged.
528</li>
Bob Wilsone44f2982010-09-13 17:39:35 +0000[diff] [blame]529
530</ul>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]531</div>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]532
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]533<!--=========================================================================-->
534<div class="doc_subsection">
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]535<a name="newapis">New Useful APIs</a>
536</div>
537
538<div class="doc_text">
539
540<p>This release includes a number of new APIs that are used internally, which
541 may also be useful for external clients.
542</p>
543
544<ul>
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]545<li></li>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]546</ul>
547
548
549</div>
550
551<!--=========================================================================-->
552<div class="doc_subsection">
553<a name="otherimprovements">Other Improvements and New Features</a>
554</div>
555
556<div class="doc_text">
557<p>Other miscellaneous features include:</p>
558
559<ul>
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]560<li></li>
Chris Lattnerc92d7692009-03-01 02:30:21 +0000[diff] [blame]561</ul>
562
563</div>
564
Chris Lattner6cb64032008-06-05 08:02:49 +0000[diff] [blame]565
566<!--=========================================================================-->
567<div class="doc_subsection">
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]568<a name="changes">Major Changes and Removed Features</a>
569</div>
570
571<div class="doc_text">
572
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]573<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]574on LLVM 2.7, this section lists some "gotchas" that you may run into upgrading
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]575from the previous release.</p>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]576
577<ul>
Chris Lattnerfc561ba2010-09-02 23:22:50 +0000[diff] [blame]578<li>.ll file doesn't produce #uses comments anymore, to get them, run a .bc file
579 through "llvm-dis --show-annotations".</li>
Chris Lattnerbd244042010-08-28 16:33:36 +0000[diff] [blame]580<li>MSIL Backend removed.</li>
581<li>ABCD and SSI passes removed.</li>
582<li>'Union' LLVM IR feature removed.</li>
Chris Lattner87e04952010-04-21 05:17:40 +0000[diff] [blame]583</ul>
Chris Lattner934e2d42008-10-13 22:06:31 +0000[diff] [blame]584
585<p>In addition, many APIs have changed in this release. Some of the major LLVM
586API changes are:</p>
587
588<ul>
Devang Pateldbf83832008-10-14 20:03:43 +0000[diff] [blame]589</ul>
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]590
Chris Lattner1e4d5bc2008-10-13 17:57:36 +0000[diff] [blame]591</div>
592
593
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]594<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]595<div class="doc_section">
596 <a name="knownproblems">Known Problems</a>
597</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]598<!-- *********************************************************************** -->
599
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]600<div class="doc_text">
601
Mikhail Glushenkov25422542009-03-01 18:09:47 +0000[diff] [blame]602<p>This section contains significant known problems with the LLVM system,
Chris Lattner2a092392008-11-10 05:40:34 +0000[diff] [blame]603listed by component. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]604href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]605there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]606
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]607</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]608
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]609<!-- ======================================================================= -->
610<div class="doc_subsection">
611 <a name="experimental">Experimental features included with this release</a>
612</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]613
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]614<div class="doc_text">
615
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]616<p>The following components of this LLVM release are either untested, known to
617be broken or unreliable, or are in early development. These components should
618not be relied on, and bugs should not be filed against them, but they may be
619useful 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]620components, please contact us on the <a
621href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]622
623<ul>
Chris Lattnerbd244042010-08-28 16:33:36 +0000[diff] [blame]624<li>The Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
Wesley Peck3aa84e52010-03-18 14:31:30 +0000[diff] [blame]625 backends are experimental.</li>
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]626<li><tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
Chris Lattnerb3fa6bf2010-07-21 15:57:40 +0000[diff] [blame]627 supported value for this option. XXX Update me</li>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]628</ul>
629
630</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]631
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]632<!-- ======================================================================= -->
633<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]634 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]635</div>
636
637<div class="doc_text">
638
639<ul>
Anton Korobeynikov486c7d32008-06-08 10:24:13 +0000[diff] [blame]640 <li>The X86 backend does not yet support
641 all <a href="http://llvm.org/PR879">inline assembly that uses the X86
642 floating point stack</a>. It supports the 'f' and 't' constraints, but not
643 'u'.</li>
Duncan Sands0bc15262008-06-08 19:38:43 +0000[diff] [blame]644 <li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]645 expect small issues to happen. Also, llvm-gcc cannot build the mingw64
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]646 runtime currently due to lack of support for the 'u' inline assembly
647 constraint and for X87 floating point inline assembly.</li>
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]648 <li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattnera67df2d2010-04-22 06:28:20 +0000[diff] [blame]649 <tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman721b3722008-06-08 23:05:11 +0000[diff] [blame]650 argument constructs on X86-64 by lowering them manually.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]651</ul>
652
653</div>
654
655<!-- ======================================================================= -->
656<div class="doc_subsection">
657 <a name="ppc-be">Known problems with the PowerPC back-end</a>
658</div>
659
660<div class="doc_text">
661
662<ul>
Nicolas Geoffray77d99502007-05-15 09:21:28 +0000[diff] [blame]663<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]664compilation, and lacks support for debug information.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]665</ul>
666
667</div>
668
669<!-- ======================================================================= -->
670<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]671 <a name="arm-be">Known problems with the ARM back-end</a>
672</div>
673
674<div class="doc_text">
675
676<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]677<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands47fc0a22007-09-26 15:59:54 +0000[diff] [blame]678processors, thumb programs can crash or produce wrong
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]679results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]680<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]681</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]682</ul>
683
684</div>
685
686<!-- ======================================================================= -->
687<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]688 <a name="sparc-be">Known problems with the SPARC back-end</a>
689</div>
690
691<div class="doc_text">
692
693<ul>
John Criswellea03c9d2009-03-02 15:28:15 +0000[diff] [blame]694<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]695 support the 64-bit SPARC ABI (-m64).</li>
696</ul>
697
698</div>
699
700<!-- ======================================================================= -->
701<div class="doc_subsection">
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]702 <a name="mips-be">Known problems with the MIPS back-end</a>
703</div>
704
705<div class="doc_text">
706
707<ul>
Bruno Cardoso Lopes24eb3de2008-10-25 14:56:26 +0000[diff] [blame]708<li>64-bit MIPS targets are not supported yet.</li>
709</ul>
710
711</div>
712
713<!-- ======================================================================= -->
714<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]715 <a name="alpha-be">Known problems with the Alpha back-end</a>
716</div>
717
718<div class="doc_text">
719
720<ul>
721
722<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
723appropriate nops inserted to ensure restartability.</li>
724
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]725</ul>
726</div>
727
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]728<!-- ======================================================================= -->
729<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]730 <a name="c-be">Known problems with the C back-end</a>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]731</div>
732
733<div class="doc_text">
734
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame^]735<p>The C backend has numerous problems and is not being actively maintained.
736Depending on it for anything serious is not advised.</p>
737
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]738<ul>
Chris Lattnera1a4c9a2008-06-05 06:35:40 +0000[diff] [blame]739<li><a href="http://llvm.org/PR802">The C backend has only basic support for
740 inline assembly code</a>.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000[diff] [blame]741<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
742 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif75b2f762009-03-02 12:02:51 +0000[diff] [blame]743 C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sandse09506a2008-02-10 13:40:55 +0000[diff] [blame]744<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands3aa36732009-02-25 11:51:54 +0000[diff] [blame]745<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]746</ul>
747
748</div>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]749
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]750
751<!-- ======================================================================= -->
752<div class="doc_subsection">
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame^]753 <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]754</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000[diff] [blame]755
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]756<div class="doc_text">
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]757
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame^]758<p>llvm-gcc is generally very stable for the C family of languages. The only
759 major language feature of GCC not supported by llvm-gcc is the
760 <tt>__builtin_apply</tt> family of builtins. However, some extensions
761 are only supported on some targets. For example, trampolines are only
762 supported on some targets (these are used when you take the address of a
763 nested function).</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]764
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame^]765<p>Fortran support generally works, but there are still several unresolved bugs
766 in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
767 tools/gfortran component for details. Note that llvm-gcc is missing major
768 Fortran performance work in the frontend and library that went into GCC after
769 4.2. If you are interested in Fortran, we recommend that you consider using
770 <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]771
Chris Lattner086d2692010-09-29 05:34:42 +0000[diff] [blame^]772<p>The llvm-gcc 4.2 Ada compiler has basic functionality. However, this is not a
773mature technology, and problems should be expected. For example:</p>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]774<ul>
Duncan Sands56448462008-06-08 20:18:35 +0000[diff] [blame]775<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]776to lack of trampoline support (pointers to nested functions) on other platforms.
777However, 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]778which does support trampolines.</li>
779<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]780This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
781exception handling, which is used internally by the compiler.
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]782Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
Duncan Sandsaef747f2008-10-13 17:27:23 +0000[diff] [blame]783<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
784and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
Duncan Sandsd34bf762009-02-25 11:59:06 +0000[diff] [blame]785(c380004 also fails with gcc-4.2 mainline).
786If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
787causes the compiler to go into an infinite loop, using up all system memory.</li>
Duncan Sands2dbb00e2009-03-02 16:35:57 +0000[diff] [blame]788<li>Some GCC specific Ada tests continue to crash the compiler.</li>
Chris Lattneraa61f412009-10-13 17:48:04 +0000[diff] [blame]789<li>The <tt>-E</tt> binder option (exception backtraces)
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]790<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]791crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]792<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
793or finish at a non-byte offset</a> in a record. Workaround: do not pack records
794or use representation clauses that result in a field of a non-discrete type
795starting or finishing in the middle of a byte.</li>
Chris Lattnerb076b002008-06-08 21:19:07 +0000[diff] [blame]796<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
797'main' as generated by the Ada binder to be invalid</a>.
798Workaround: hand edit the file to use pointers for <tt>argv</tt> and
799<tt>envp</tt> rather than integers.</li>
800<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
801ignored</a>.</li>
Chris Lattnere38ac152008-02-12 06:29:45 +0000[diff] [blame]802</ul>
803</div>
804
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]805<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]806<div class="doc_section">
807 <a name="additionalinfo">Additional Information</a>
808</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]809<!-- *********************************************************************** -->
810
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]811<div class="doc_text">
812
Chris Lattnercb5596d2005-05-16 17:13:10 +0000[diff] [blame]813<p>A wide variety of additional information is available on the <a
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]814href="http://llvm.org">LLVM web page</a>, in particular in the <a
815href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]816contains versions of the API documentation which is up-to-date with the
817Subversion version of the source code.
Misha Brukman96158092005-03-30 19:14:24 +0000[diff] [blame]818You can access versions of these documents specific to this release by going
819into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]820
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]821<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]822us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]823lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]824
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]825</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]826
827<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]828
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]829<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]830<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000[diff] [blame]831 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]832 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]833 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]834 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]835
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]836 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]837 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]838</address>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]839
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]840</body>
841</html>