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Reid Spencer	6454ed3	2004-11-18 18:38:58 +0000	[diff] [blame]	5	<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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Dan Gohman	b44f6c6	2010-05-03 23:51:05 +0000	[diff] [blame]	8	<title>LLVM 2.8 Release Notes</title>
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	9	</head>
				10	<body>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	11
Dan Gohman	b44f6c6	2010-05-03 23:51:05 +0000	[diff] [blame]	12	<div class="doc_title">LLVM 2.8 Release Notes</div>
Mikhail Glushenkov	ea65d7d	2008-10-13 02:08:34 +0000	[diff] [blame]	13
Chris Lattner	0e464a9	2010-03-17 04:02:39 +0000	[diff] [blame]	14	<img align=right src="http://llvm.org/img/DragonSmall.png"
Gabor Greif	ee2187a	2010-04-22 10:21:43 +0000	[diff] [blame]	15	width="136" height="136" alt="LLVM Dragon Logo">
Chris Lattner	0e464a9	2010-03-17 04:02:39 +0000	[diff] [blame]	16
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	17	<ol>
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	18	<li><a href="#intro">Introduction</a></li>
Chris Lattner	96a445e	2008-10-13 18:01:01 +0000	[diff] [blame]	19	<li><a href="#subproj">Sub-project Status Update</a></li>
Dan Gohman	b44f6c6	2010-05-03 23:51:05 +0000	[diff] [blame]	20	<li><a href="#externalproj">External Projects Using LLVM 2.8</a></li>
				21	<li><a href="#whatsnew">What's New in LLVM 2.8?</a></li>
Chris Lattner	4b538b9	2004-04-30 22:17:12 +0000	[diff] [blame]	22	<li><a href="GettingStarted.html">Installation Instructions</a></li>
Dan Gohman	44aa921	2008-10-14 16:23:02 +0000	[diff] [blame]	23	<li><a href="#knownproblems">Known Problems</a></li>
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	24	<li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	25	</ol>
				26
Chris Lattner	7911ce2	2004-05-23 21:07:27 +0000	[diff] [blame]	27	<div class="doc_author">
Dan Gohman	44aa921	2008-10-14 16:23:02 +0000	[diff] [blame]	28	<p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	29	</div>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	30
Chris Lattner	e07043c	2010-09-29 05:30:03 +0000	[diff] [blame]	31	<!--
Chris Lattner	7b91eda	2010-04-22 05:41:35 +0000	[diff] [blame]	32	<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.8
Jeffrey Yasskin	bec4877	2010-01-28 01:14:43 +0000	[diff] [blame]	33	release.<br>
				34	You may prefer the
Dan Gohman	b44f6c6	2010-05-03 23:51:05 +0000	[diff] [blame]	35	<a href="http://llvm.org/releases/2.7/docs/ReleaseNotes.html">LLVM 2.7
				36	Release Notes</a>.</h1>
Chris Lattner	e07043c	2010-09-29 05:30:03 +0000	[diff] [blame]	37	-->
Jeffrey Yasskin	bec4877	2010-01-28 01:14:43 +0000	[diff] [blame]	38
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	39	<!-- *********************************************************************** -->
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	40	<div class="doc_section">
				41	<a name="intro">Introduction</a>
				42	</div>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	43	<!-- *********************************************************************** -->
				44
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	45	<div class="doc_text">
				46
Chris Lattner	f6662f9	2008-10-13 17:57:36 +0000	[diff] [blame]	47	<p>This document contains the release notes for the LLVM Compiler
Dan Gohman	7ae3ac8	2010-05-03 23:52:21 +0000	[diff] [blame]	48	Infrastructure, release 2.8. Here we describe the status of LLVM, including
Chris Lattner	f6662f9	2008-10-13 17:57:36 +0000	[diff] [blame]	49	major improvements from the previous release and significant known problems.
Mikhail Glushenkov	f795ef0	2009-03-01 18:09:47 +0000	[diff] [blame]	50	All LLVM releases may be downloaded from the <a
Chris Lattner	f6662f9	2008-10-13 17:57:36 +0000	[diff] [blame]	51	href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
Chris Lattner	1909261	2003-10-02 16:38:05 +0000	[diff] [blame]	52
Chris Lattner	7506b1d	2004-12-07 08:04:13 +0000	[diff] [blame]	53	<p>For more information about LLVM, including information about the latest
Chris Lattner	c463b27	2005-10-29 07:07:09 +0000	[diff] [blame]	54	release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner	47ad72c	2003-10-07 21:38:31 +0000	[diff] [blame]	55	web site</a>. If you have questions or comments, the <a
Chris Lattner	c66bfef	2010-03-17 04:41:49 +0000	[diff] [blame]	56	href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's
				57	Mailing List</a> is a good place to send them.</p>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	58
Mikhail Glushenkov	ea65d7d	2008-10-13 02:08:34 +0000	[diff] [blame]	59	<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner	8497764	2007-09-21 03:54:09 +0000	[diff] [blame]	60	main LLVM web page, this document applies to the <i>next</i> release, not the
Gabor Greif	fa933f8	2008-10-14 11:00:32 +0000	[diff] [blame]	61	current one. To see the release notes for a specific release, please see the
Chris Lattner	8497764	2007-09-21 03:54:09 +0000	[diff] [blame]	62	<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	63
				64	</div>
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	65
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	66
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	67	<!--
				68	Almost dead code.
				69	include/llvm/Analysis/LiveValues.h => Dan
				70	lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8.
Chris Lattner	61c70e9	2010-08-28 04:09:24 +0000	[diff] [blame]	71	GEPSplitterPass
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	72	-->
				73
				74
Chris Lattner	e07043c	2010-09-29 05:30:03 +0000	[diff] [blame]	75	<!-- Features that need text if they're finished for 2.9:
Chris Lattner	914ce46	2010-04-22 06:28:20 +0000	[diff] [blame]	76	combiner-aa?
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	77	strong phi elim
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	78	loop dependence analysis
Chris Lattner	885b661	2010-08-28 16:33:36 +0000	[diff] [blame]	79	TBAA
Chris Lattner	e07043c	2010-09-29 05:30:03 +0000	[diff] [blame]	80	CorrelatedValuePropagation
Chris Lattner	acce85d	2008-02-10 07:46:44 +0000	[diff] [blame]	81	-->
Chris Lattner	e07043c	2010-09-29 05:30:03 +0000	[diff] [blame]	82
				83	<!-- Announcement, lldb, libc++ -->
Chris Lattner	afa4163	2010-09-29 07:25:03 +0000	[diff] [blame]	84
Chris Lattner	acce85d	2008-02-10 07:46:44 +0000	[diff] [blame]	85
Chris Lattner	96a445e	2008-10-13 18:01:01 +0000	[diff] [blame]	86	<!-- *********************************************************************** -->
				87	<div class="doc_section">
				88	<a name="subproj">Sub-project Status Update</a>
Chris Lattner	ea34f64	2008-06-08 21:34:41 +0000	[diff] [blame]	89	</div>
Chris Lattner	96a445e	2008-10-13 18:01:01 +0000	[diff] [blame]	90	<!-- *********************************************************************** -->
Chris Lattner	ea34f64	2008-06-08 21:34:41 +0000	[diff] [blame]	91
				92	<div class="doc_text">
Chris Lattner	8348b47	2008-06-08 21:58:17 +0000	[diff] [blame]	93	<p>
Dan Gohman	b44f6c6	2010-05-03 23:51:05 +0000	[diff] [blame]	94	The LLVM 2.8 distribution currently consists of code from the core LLVM
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	95	repository (which roughly includes the LLVM optimizers, code generators
				96	and supporting tools), the Clang repository and the llvm-gcc repository. In
				97	addition to this code, the LLVM Project includes other sub-projects that are in
				98	development. Here we include updates on these subprojects.
Bill Wendling	63d8c55	2009-03-02 04:28:57 +0000	[diff] [blame]	99	</p>
Chris Lattner	96a445e	2008-10-13 18:01:01 +0000	[diff] [blame]	100
Chris Lattner	8348b47	2008-06-08 21:58:17 +0000	[diff] [blame]	101	</div>
				102
Chris Lattner	96a445e	2008-10-13 18:01:01 +0000	[diff] [blame]	103
Chris Lattner	8348b47	2008-06-08 21:58:17 +0000	[diff] [blame]	104	<!--=========================================================================-->
Chris Lattner	96a445e	2008-10-13 18:01:01 +0000	[diff] [blame]	105	<div class="doc_subsection">
Chris Lattner	fb97b2d	2008-10-13 18:11:54 +0000	[diff] [blame]	106	<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
Chris Lattner	8348b47	2008-06-08 21:58:17 +0000	[diff] [blame]	107	</div>
				108
				109	<div class="doc_text">
				110
Chris Lattner	095539f	2010-04-26 17:42:18 +0000	[diff] [blame]	111	<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
				112	C++, and Objective-C languages. Clang aims to provide a better user experience
				113	through expressive diagnostics, a high level of conformance to language
				114	standards, fast compilation, and low memory use. Like LLVM, Clang provides a
				115	modular, library-based architecture that makes it suitable for creating or
				116	integrating with other development tools. Clang is considered a
Chris Lattner	e07043c	2010-09-29 05:30:03 +0000	[diff] [blame]	117	production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
				118	(32- and 64-bit), and for darwin-arm targets.</p>
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	119
Chris Lattner	922d00f	2010-07-21 15:57:40 +0000	[diff] [blame]	120	<p>In the LLVM 2.8 time-frame, the Clang team has made many improvements:</p>
Bill Wendling	741748a	2008-10-27 09:27:33 +0000	[diff] [blame]	121
Douglas Gregor	f2409d5	2010-10-04 07:02:35 +0000	[diff] [blame]	122	<ul>
				123	<li>Clang C++ is now feature-complete with respect to the ISO C++ 1998 and 2003 standards.</li>
				124	<li>Added support for Objective-C++.</li>
				125	<li>Clang now uses LLVM-MC to directly generate object code and to parse inline assembly (on Darwin).</li>
				126	<li>Introduced many new warnings, including <code>-Wmissing-field-initializers</code>, <code>-Wshadow</code>, <code>-Wno-protocol</code>, <code>-Wtautological-compare</code>, <code>-Wstrict-selector-match</code>, <code>-Wcast-align</code>, <code>-Wunused</code> improvements, and greatly improved format-string checking.</li>
				127	<li>Introduced the "libclang" library, a C interface to Clang intended to support IDE clients.</li>
				128	<li>Added support for <code>#pragma GCC visibility</code>, <code>#pragma align</code>, and others.</li>
Duncan Sands	051f2ee	2010-10-04 09:11:50 +0000	[diff] [blame]	129	<li>Added support for SSE, ARM NEON, and Altivec.</li>
Douglas Gregor	f2409d5	2010-10-04 07:02:35 +0000	[diff] [blame]	130	<li>Implemented support for blocks in C++.</li>
				131	<li>Implemented precompiled headers for C++.</li>
				132	<li>Improved abstract syntax trees to retain more accurate source information.</li>
				133	</ul>
Chris Lattner	fb97b2d	2008-10-13 18:11:54 +0000	[diff] [blame]	134	</div>
				135
				136	<!--=========================================================================-->
				137	<div class="doc_subsection">
				138	<a name="clangsa">Clang Static Analyzer</a>
				139	</div>
				140
				141	<div class="doc_text">
				142
Chris Lattner	8cdd793	2010-04-22 06:38:11 +0000	[diff] [blame]	143	<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a>
				144	project is an effort to use static source code analysis techniques to
				145	automatically find bugs in C and Objective-C programs (and hopefully <a
				146	href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the
				147	future</a>!). The tool is very good at finding bugs that occur on specific
				148	paths through code, such as on error conditions.</p>
Chris Lattner	cc04261	2008-10-14 00:52:49 +0000	[diff] [blame]	149
Chris Lattner	2e38c7f	2010-09-30 00:34:43 +0000	[diff] [blame]	150	<p>The LLVM 2.8 release fixes a number of bugs and slightly improves precision
				151	over 2.7, but there are no major new features in the release.
Chris Lattner	8cdd793	2010-04-22 06:38:11 +0000	[diff] [blame]	152	</p>
Chris Lattner	8348b47	2008-06-08 21:58:17 +0000	[diff] [blame]	153
				154	</div>
				155
Chris Lattner	96a445e	2008-10-13 18:01:01 +0000	[diff] [blame]	156	<!--=========================================================================-->
				157	<div class="doc_subsection">
Duncan Sands	749fd83	2010-04-02 09:23:15 +0000	[diff] [blame]	158	<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	159	</div>
				160
				161	<div class="doc_text">
				162	<p>
Duncan Sands	749fd83	2010-04-02 09:23:15 +0000	[diff] [blame]	163	<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
Duncan Sands	4b1da2b	2010-09-30 17:37:34 +0000	[diff] [blame]	164	gcc-4.5. Unlike llvm-gcc, dragonegg in theory does not require any gcc-4.5
				165	modifications whatsoever (currently one small patch is needed) thanks to the
				166	new <a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>.
				167	DragonEgg is a gcc plugin that makes gcc-4.5 use the LLVM optimizers and code
				168	generators instead of gcc's, just like with llvm-gcc.
Duncan Sands	749fd83	2010-04-02 09:23:15 +0000	[diff] [blame]	169	</p>
				170
				171	<p>
Duncan Sands	4b1da2b	2010-09-30 17:37:34 +0000	[diff] [blame]	172	DragonEgg is still a work in progress, but it is able to compile a lot of code,
				173	for example all of gcc, LLVM and clang. Currently Ada, C, C++ and Fortran work
				174	well, while all other languages either don't work at all or only work poorly.
				175	For the moment only the x86-32 and x86-64 targets are supported, and only on
				176	linux and darwin (darwin may need additional gcc patches).
Duncan Sands	749fd83	2010-04-02 09:23:15 +0000	[diff] [blame]	177	</p>
				178
				179	<p>
Duncan Sands	4b1da2b	2010-09-30 17:37:34 +0000	[diff] [blame]	180	The 2.8 release has the following notable changes:
				181	<ul>
				182	<li>The plugin loads faster due to exporting fewer symbols.</li>
				183	<li>Additional vector operations such as addps256 are now supported.</li>
				184	<li>Ada global variables with no initial value are no longer zero initialized,
				185	resulting in better optimization.</li>
				186	<li>The '-fplugin-arg-dragonegg-enable-gcc-optzns' flag now runs all gcc
				187	optimizers, rather than just a handful.</li>
				188	<li>Fortran programs using common variables now link correctly.</li>
				189	<li>GNU OMP constructs no longer crash the compiler.</li>
				190	</ul>
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	191	</p>
				192
				193	</div>
				194
Chris Lattner	7554771	2010-10-03 23:49:06 +0000	[diff] [blame]	195	<!--=========================================================================-->
				196	<div class="doc_subsection">
				197	<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
				198	</div>
				199
				200	<div class="doc_text">
				201	<p>
				202	The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
				203	a Java Virtual Machine (Java VM or JVM) that uses LLVM for static and
				204	just-in-time compilation. As of LLVM 2.8, VMKit now supports copying garbage
				205	collectors, and can be configured to use MMTk's copy mark-sweep garbage
				206	collector. In LLVM 2.8, the VMKit .NET VM is no longer being maintained.
				207	</p>
				208	</div>
				209
				210	<!--=========================================================================-->
				211	<div class="doc_subsection">
				212	<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
				213	</div>
				214
				215	<div class="doc_text">
				216	<p>
				217	The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
				218	is a simple library that provides an implementation of the low-level
				219	target-specific hooks required by code generation and other runtime components.
				220	For example, when compiling for a 32-bit target, converting a double to a 64-bit
				221	unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
				222	function. The compiler-rt library provides highly optimized implementations of
				223	this and other low-level routines (some are 3x faster than the equivalent
				224	libgcc routines).</p>
				225
				226	<p>
				227	All of the code in the compiler-rt project is available under the standard LLVM
				228	License, a "BSD-style" license. New in LLVM 2.8, compiler_rt now supports
				229	soft floating point (for targets that don't have a real floating point unit),
				230	and includes an extensive testsuite for the "blocks" language feature and the
				231	blocks runtime included in compiler_rt.</p>
				232
				233	</div>
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	234
				235	<!--=========================================================================-->
				236	<div class="doc_subsection">
Chris Lattner	e07043c	2010-09-29 05:30:03 +0000	[diff] [blame]	237	<a name="lldb">LLDB: Low Level Debugger</a>
				238	</div>
				239
				240	<div class="doc_text">
				241	<p>
Chris Lattner	7554771	2010-10-03 23:49:06 +0000	[diff] [blame]	242	<a href="http://lldb.llvm.org/">LLDB</a> is a brand new member of the LLVM
				243	umbrella of projects. LLDB is a next generation, high-performance debugger. It
				244	is built as a set of reusable components which highly leverage existing
				245	libraries in the larger LLVM Project, such as the Clang expression parser, the
				246	LLVM disassembler and the LLVM JIT.</p>
Chris Lattner	e07043c	2010-09-29 05:30:03 +0000	[diff] [blame]	247
				248	<p>
Chris Lattner	7554771	2010-10-03 23:49:06 +0000	[diff] [blame]	249	LLDB is in early development and not included as part of the LLVM 2.8 release,
				250	but is mature enough to support basic debugging scenarios on Mac OS X in C,
				251	Objective-C and C++. We'd really like help extending and expanding LLDB to
				252	support new platforms, new languages, new architectures, and new features.
Chris Lattner	e07043c	2010-09-29 05:30:03 +0000	[diff] [blame]	253	</p>
				254
				255	</div>
				256
				257	<!--=========================================================================-->
				258	<div class="doc_subsection">
				259	<a name="libc++">libc++: C++ Standard Library</a>
				260	</div>
				261
				262	<div class="doc_text">
				263	<p>
Chris Lattner	7554771	2010-10-03 23:49:06 +0000	[diff] [blame]	264	<a href="http://libc++.llvm.org/">libc++</a> is another new member of the LLVM
				265	family. It is an implementation of the C++ standard library, written from the
				266	ground up to specifically target the forthcoming C++'0X standard and focus on
				267	delivering great performance.</p>
Chris Lattner	e07043c	2010-09-29 05:30:03 +0000	[diff] [blame]	268
				269	<p>
Chris Lattner	7554771	2010-10-03 23:49:06 +0000	[diff] [blame]	270	As of the LLVM 2.8 release, libc++ is virtually feature complete, but would
				271	benefit from more testing and better integration with Clang++. It is also
				272	looking forward to the C++ committee finalizing the C++'0x standard.
Chris Lattner	e07043c	2010-09-29 05:30:03 +0000	[diff] [blame]	273	</p>
				274
				275	</div>
				276
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	277
Chris Lattner	ab68e9e	2009-02-26 22:33:38 +0000	[diff] [blame]	278	<!-- *********************************************************************** -->
				279	<div class="doc_section">
Chris Lattner	922d00f	2010-07-21 15:57:40 +0000	[diff] [blame]	280	<a name="externalproj">External Open Source Projects Using LLVM 2.8</a>
Chris Lattner	ab68e9e	2009-02-26 22:33:38 +0000	[diff] [blame]	281	</div>
				282	<!-- *********************************************************************** -->
				283
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	284	<div class="doc_text">
				285
				286	<p>An exciting aspect of LLVM is that it is used as an enabling technology for
				287	a lot of other language and tools projects. This section lists some of the
Chris Lattner	922d00f	2010-07-21 15:57:40 +0000	[diff] [blame]	288	projects that have already been updated to work with LLVM 2.8.</p>
Chris Lattner	7c8e796	2010-04-26 17:38:10 +0000	[diff] [blame]	289	</div>
				290
Chris Lattner	2e38c7f	2010-09-30 00:34:43 +0000	[diff] [blame]	291	<!--=========================================================================-->
				292	<div class="doc_subsection">
				293	<a name="tce">TTA-based Codesign Environment (TCE)</a>
				294	</div>
				295
				296	<div class="doc_text">
				297	<p>
				298	<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing
				299	application-specific processors (ASP) based on the Transport triggered
				300	architecture (TTA). The toolset provides a complete co-design flow from C/C++
				301	programs down to synthesizable VHDL and parallel program binaries. Processor
				302	customization points include the register files, function units, supported
				303	operations, and the interconnection network.</p>
				304
				305	<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target
				306	independent optimizations and also for parts of code generation. It generates
				307	new LLVM-based code generators "on the fly" for the designed TTA processors and
				308	loads them in to the compiler backend as runtime libraries to avoid per-target
				309	recompilation of larger parts of the compiler chain.</p>
				310
				311	</div>
				312
				313	<!--=========================================================================-->
				314	<div class="doc_subsection">
				315	<a name="Horizon">Horizon Bytecode Compiler</a>
				316	</div>
				317
				318	<div class="doc_text">
				319	<p>
				320	<a href="http://www.quokforge.org/projects/horizon">Horizon</a> is a bytecode
				321	language and compiler written on top of LLVM, intended for producing
				322	single-address-space managed code operating systems that
				323	run faster than the equivalent multiple-address-space C systems.
Gabor Greif	9f45913	2010-10-04 17:03:49 +0000	[diff] [blame^]	324	More in-depth blurb is available on the <a
				325	href="http://www.quokforge.org/projects/horizon/wiki/Wiki">wiki</a>.</p>
Chris Lattner	2e38c7f	2010-09-30 00:34:43 +0000	[diff] [blame]	326
				327	</div>
				328
				329	<!--=========================================================================-->
				330	<div class="doc_subsection">
				331	<a name="clamav">Clam AntiVirus</a>
				332	</div>
				333
				334	<div class="doc_text">
				335	<p>
				336	<a href=http://www.clamav.net>Clam AntiVirus</a> is an open source (GPL)
				337	anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail
				338	gateways. Since version 0.96 it has <a
				339	href="http://vrt-sourcefire.blogspot.com/2010/09/introduction-to-clamavs-low-level.html">bytecode
				340	signatures</a> that allow writing detections for complex malware. It
				341	uses LLVM's JIT to speed up the execution of bytecode on
Gabor Greif	9f45913	2010-10-04 17:03:49 +0000	[diff] [blame^]	342	X86, X86-64, PPC32/64, falling back to its own interpreter otherwise.
				343	The git version was updated to work with LLVM 2.8.
Chris Lattner	2e38c7f	2010-09-30 00:34:43 +0000	[diff] [blame]	344	</p>
				345
				346	<p>The <a
				347	href="http://git.clamav.net/gitweb?p=clamav-bytecode-compiler.git;a=blob_plain;f=docs/user/clambc-user.pdf">
				348	ClamAV bytecode compiler</a> uses Clang and LLVM to compile a C-like
				349	language, insert runtime checks, and generate ClamAV bytecode.</p>
				350
				351	</div>
				352
				353	<!--=========================================================================-->
				354	<div class="doc_subsection">
				355	<a name="pure">Pure</a>
				356	</div>
				357
				358	<div class="doc_text">
				359	<p>
				360	<a href="http://pure-lang.googlecode.com/">Pure</a>
				361	is an algebraic/functional
				362	programming language based on term rewriting. Programs are collections
				363	of equations which are used to evaluate expressions in a symbolic
				364	fashion. Pure offers dynamic typing, eager and lazy evaluation, lexical
				365	closures, a hygienic macro system (also based on term rewriting),
				366	built-in list and matrix support (including list and matrix
				367	comprehensions) and an easy-to-use C interface. The interpreter uses
				368	LLVM as a backend to JIT-compile Pure programs to fast native code.</p>
				369
				370	<p>Pure versions 0.44 and later have been tested and are known to work with
				371	LLVM 2.8 (and continue to work with older LLVM releases >= 2.5).</p>
				372
				373	</div>
				374
				375	<!--=========================================================================-->
				376	<div class="doc_subsection">
				377	<a name="GHC">Glasgow Haskell Compiler (GHC)</a>
				378	</div>
				379
				380	<div class="doc_text">
				381	<p>
				382	<a href="http://www.haskell.org/ghc/">GHC</a> is an open source,
				383	state-of-the-art programming suite for
				384	Haskell, a standard lazy functional programming language. It includes
				385	an optimizing static compiler generating good code for a variety of
				386	platforms, together with an interactive system for convenient, quick
				387	development.</p>
				388
				389	<p>In addition to the existing C and native code generators, GHC 7.0 now
				390	supports an <a
				391	href="http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/Backends/LLVM">LLVM
				392	code generator</a>. GHC supports LLVM 2.7 and later.</p>
				393
				394	</div>
				395
				396	<!--=========================================================================-->
				397	<div class="doc_subsection">
				398	<a name="Clay">Clay Programming Language</a>
				399	</div>
				400
				401	<div class="doc_text">
				402	<p>
Chris Lattner	97fe645	2010-09-30 01:12:09 +0000	[diff] [blame]	403	<a href="http://tachyon.in/clay/">Clay</a> is a new systems programming
Chris Lattner	2e38c7f	2010-09-30 00:34:43 +0000	[diff] [blame]	404	language that is specifically designed for generic programming. It makes
				405	generic programming very concise thanks to whole program type propagation. It
				406	uses LLVM as its backend.</p>
				407
				408	</div>
Chris Lattner	3a1d4cf	2010-04-22 21:34:16 +0000	[diff] [blame]	409
Chris Lattner	e051844	2010-10-01 06:34:49 +0000	[diff] [blame]	410	<!--=========================================================================-->
				411	<div class="doc_subsection">
				412	<a name="llvm-py">llvm-py Python Bindings for LLVM</a>
				413	</div>
				414
				415	<div class="doc_text">
				416	<p>
				417	<a href="http://www.mdevan.org/llvm-py/">llvm-py</a> has been updated to work
				418	with LLVM 2.8. llvm-py provides Python bindings for LLVM, allowing you to write a
				419	compiler backend or a VM in Python.</p>
				420
				421	</div>
				422
				423
Chris Lattner	2fb6e5c	2010-10-03 23:09:03 +0000	[diff] [blame]	424	<!--=========================================================================-->
				425	<div class="doc_subsection">
				426	<a name="FAUST">FAUST Real-Time Audio Signal Processing Language</a>
				427	</div>
				428
				429	<div class="doc_text">
				430	<p>
				431	<a href="http://faust.grame.fr">FAUST</a> is a compiled language for real-time
				432	audio signal processing. The name FAUST stands for Functional AUdio STream. Its
				433	programming model combines two approaches: functional programming and block
				434	diagram composition. In addition with the C, C++, JAVA output formats, the
				435	Faust compiler can now generate LLVM bitcode, and works with LLVM 2.7 and
				436	2.8.</p>
				437
				438	</div>
				439
				440	<!--=========================================================================-->
				441	<div class="doc_subsection">
				442	<a name="jade">Jade Just-in-time Adaptive Decoder Engine</a>
				443	</div>
				444
				445	<div class="doc_text">
				446	<p><a
				447	href="http://sourceforge.net/apps/trac/orcc/wiki/JadeDocumentation">Jade</a>
				448	(Just-in-time Adaptive Decoder Engine) is a generic video decoder engine using
				449	LLVM for just-in-time compilation of video decoder configurations. Those
				450	configurations are designed by MPEG Reconfigurable Video Coding (RVC) committee.
				451	MPEG RVC standard is built on a stream-based dataflow representation of
				452	decoders. It is composed of a standard library of coding tools written in
Duncan Sands	30be9e4	2010-10-04 10:04:14 +0000	[diff] [blame]	453	RVC-CAL language and a dataflow configuration — block diagram —
Chris Lattner	2fb6e5c	2010-10-03 23:09:03 +0000	[diff] [blame]	454	of a decoder.</p>
				455
				456	<p>Jade project is hosted as part of the <a href="http://orcc.sf.net">Open
				457	RVC-CAL Compiler</a> and requires it to translate the RVC-CAL standard library
				458	of video coding tools into an LLVM assembly code.</p>
				459
				460	</div>
				461
				462	<!--=========================================================================-->
				463	<div class="doc_subsection">
				464	<a name="neko_llvm_jit">LLVM JIT for Neko VM</a>
				465	</div>
				466
				467	<div class="doc_text">
				468	<p><a href="http://github.com/vava/neko_llvm_jit">Neko LLVM JIT</a>
				469	replaces the standard Neko JIT with an LLVM-based implementation. While not
				470	fully complete, it is already providing a 1.5x speedup on 64-bit systems.
				471	Neko LLVM JIT requires LLVM 2.8 or later.</p>
				472
				473	</div>
				474
				475	<!--=========================================================================-->
				476	<div class="doc_subsection">
				477	<a name="crack">Crack Scripting Language</a>
				478	</div>
				479
				480	<div class="doc_text">
				481	<p>
				482	<a href="http://code.google.com/p/crack-language/">Crack</a> aims to provide
				483	the ease of development of a scripting language with the performance of a
				484	compiled language. The language derives concepts from C++, Java and Python,
				485	incorporating object-oriented programming, operator overloading and strong
				486	typing. Crack 0.2 works with LLVM 2.7, and the forthcoming Crack 0.2.1 release
				487	builds on LLVM 2.8.</p>
				488
				489	</div>
				490
				491	<!--=========================================================================-->
				492	<div class="doc_subsection">
				493	<a name="DresdenTM">Dresden TM Compiler (DTMC)</a>
				494	</div>
				495
				496	<div class="doc_text">
				497	<p>
				498	<a href="http://tm.inf.tu-dresden.de">DTMC</a> provides support for
				499	Transactional Memory, which is an easy-to-use and efficient way to synchronize
				500	accesses to shared memory. Transactions can contain normal C/C++ code (e.g.,
Gabor Greif	9f45913	2010-10-04 17:03:49 +0000	[diff] [blame^]	501	<code>__transaction { list.remove(x); x.refCount--; }</code>) and will be executed
Chris Lattner	2fb6e5c	2010-10-03 23:09:03 +0000	[diff] [blame]	502	virtually atomically and isolated from other transactions.</p>
				503
				504	</div>
				505
				506	<!--=========================================================================-->
				507	<div class="doc_subsection">
Chris Lattner	c5fd156	2010-10-04 16:06:37 +0000	[diff] [blame]	508	<a name="Kai">Kai Programming Language</a>
Chris Lattner	2fb6e5c	2010-10-03 23:09:03 +0000	[diff] [blame]	509	</div>
				510
				511	<div class="doc_text">
				512	<p>
				513	<a href="http://www.oriontransfer.co.nz/research/kai">Kai</a> (Japanese 会 for
				514	meeting/gathering) is an experimental interpreter that provides a highly
				515	extensible runtime environment and explicit control over the compilation
				516	process. Programs are defined using nested symbolic expressions, which are all
				517	parsed into first-class values with minimal intrinsic semantics. Kai can
				518	generate optimised code at run-time (using LLVM) in order to exploit the nature
				519	of the underlying hardware and to integrate with external software libraries.
				520	It is a unique exploration into world of dynamic code compilation, and the
				521	interaction between high level and low level semantics.</p>
				522
				523	</div>
				524
Chris Lattner	7554771	2010-10-03 23:49:06 +0000	[diff] [blame]	525	<!--=========================================================================-->
				526	<div class="doc_subsection">
				527	<a name="OSL">OSL: Open Shading Language</a>
				528	</div>
				529
				530	<div class="doc_text">
				531	<p>
				532	<a href="http://code.google.com/p/openshadinglanguage/">OSL</a> is a shading
				533	language designed for use in physically based renderers and in particular
				534	production rendering. By using LLVM instead of the interpreter, it was able to
				535	meet its performance goals (>= C-code) while retaining the benefits of
				536	runtime specialization and a portable high-level language.
				537	</p>
				538
				539	</div>
				540
				541
Chris Lattner	e051844	2010-10-01 06:34:49 +0000	[diff] [blame]	542
Chris Lattner	8348b47	2008-06-08 21:58:17 +0000	[diff] [blame]	543	<!-- *********************************************************************** -->
				544	<div class="doc_section">
Chris Lattner	922d00f	2010-07-21 15:57:40 +0000	[diff] [blame]	545	<a name="whatsnew">What's New in LLVM 2.8?</a>
Chris Lattner	8348b47	2008-06-08 21:58:17 +0000	[diff] [blame]	546	</div>
				547	<!-- *********************************************************************** -->
				548
Chris Lattner	f8e0b4e	2008-06-08 22:59:35 +0000	[diff] [blame]	549	<div class="doc_text">
				550
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	551	<p>This release includes a huge number of bug fixes, performance tweaks and
Chris Lattner	f6662f9	2008-10-13 17:57:36 +0000	[diff] [blame]	552	minor improvements. Some of the major improvements and new features are listed
				553	in this section.
Chris Lattner	f8e0b4e	2008-06-08 22:59:35 +0000	[diff] [blame]	554	</p>
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	555
Chris Lattner	914ce46	2010-04-22 06:28:20 +0000	[diff] [blame]	556	</div>
				557
				558	<!--=========================================================================-->
				559	<div class="doc_subsection">
Chris Lattner	252b83d	2008-02-06 18:00:06 +0000	[diff] [blame]	560	<a name="majorfeatures">Major New Features</a>
				561	</div>
				562
				563	<div class="doc_text">
				564
Chris Lattner	922d00f	2010-07-21 15:57:40 +0000	[diff] [blame]	565	<p>LLVM 2.8 includes several major new capabilities:</p>
Chris Lattner	f3e5bc6	2007-05-14 06:56:09 +0000	[diff] [blame]	566
				567	<ul>
Chris Lattner	11b6611	2010-10-04 02:42:39 +0000	[diff] [blame]	568	<li>As mentioned above, <a href="#libc++">libc++</a> and <a
				569	href="#lldb">LLDB</a> are major new additions to the LLVM collective.</li>
				570	<li>LLVM 2.8 now has pretty decent support for debugging optimized code. You
				571	should be able to reliably get debug info for function arguments, assuming
				572	that the value is actually available where you have stopped.</li>
				573	</ul>
				574	<li>A new 'llvm-diff' tool is available that does a semantic diff of .ll
				575	files.</li>
				576	<li>The <a href="#mc">MC subproject</a> has made major progress in this release.
				577	Direct .o file writing support for darwin/x86[-64] is now reliable and
				578	support for other targets and object file formats are in progress.</li>
Chris Lattner	8170c10	2008-02-10 08:18:42 +0000	[diff] [blame]	579	</ul>
Chris Lattner	dc91008	2010-03-17 06:41:58 +0000	[diff] [blame]	580
Chris Lattner	f3e5bc6	2007-05-14 06:56:09 +0000	[diff] [blame]	581	</div>
				582
Chris Lattner	8497764	2007-09-21 03:54:09 +0000	[diff] [blame]	583	<!--=========================================================================-->
				584	<div class="doc_subsection">
Chris Lattner	917cc71	2009-03-02 02:37:32 +0000	[diff] [blame]	585	<a name="coreimprovements">LLVM IR and Core Improvements</a>
Chris Lattner	f304ffc	2008-02-10 08:17:19 +0000	[diff] [blame]	586	</div>
				587
				588	<div class="doc_text">
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	589	<p>LLVM IR has several new features for better support of new targets and that
				590	expose new optimization opportunities:</p>
Chris Lattner	f304ffc	2008-02-10 08:17:19 +0000	[diff] [blame]	591
Chris Lattner	791f77b	2008-06-05 06:25:56 +0000	[diff] [blame]	592	<ul>
Chris Lattner	11b6611	2010-10-04 02:42:39 +0000	[diff] [blame]	593	<li>The <a href="LangRef.html#int_libc">memcpy, memmove, and memset</a>
				594	intrinsics now take address space qualified pointers and a bit to indicate
				595	whether the transfer is "<a href="LangRef.html#volatile">volatile</a>" or not.
				596	</li>
				597	<li>Per-instruction debug info metadata is much faster and uses less memory by
				598	using the new DebugLoc class.</li>
				599	<li>LLVM IR now has a more formalized concept of "<a
				600	href="LangRef.html#trapvalues">trap values</a>", which allow the optimizer
				601	to optimize more aggressively in the presence of undefined behavior, while
				602	still producing predictable results.</li>
				603	<li>LLVM IR now supports two new <a href="LangRef.html#linkage">linkage
				604	types</a> (linker_private_weak and linker_private_weak_def_auto) which map
				605	onto some obscure MachO concepts.</li>
Chris Lattner	f304ffc	2008-02-10 08:17:19 +0000	[diff] [blame]	606	</ul>
Mikhail Glushenkov	ea65d7d	2008-10-13 02:08:34 +0000	[diff] [blame]	607
Chris Lattner	f304ffc	2008-02-10 08:17:19 +0000	[diff] [blame]	608	</div>
				609
				610	<!--=========================================================================-->
				611	<div class="doc_subsection">
Chris Lattner	acce85d	2008-02-10 07:46:44 +0000	[diff] [blame]	612	<a name="optimizer">Optimizer Improvements</a>
				613	</div>
				614
				615	<div class="doc_text">
				616
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	617	<p>In addition to a large array of minor performance tweaks and bug fixes, this
Chris Lattner	f301387	2008-10-13 21:50:36 +0000	[diff] [blame]	618	release includes a few major enhancements and additions to the optimizers:</p>
Chris Lattner	acce85d	2008-02-10 07:46:44 +0000	[diff] [blame]	619
				620	<ul>
Chris Lattner	11b6611	2010-10-04 02:42:39 +0000	[diff] [blame]	621	<li>As mentioned above, the optimizer now has support for updating debug
				622	information as it goes. A key aspect of this is the new <a
				623	href="SourceLevelDebugging.html#format_common_value">llvm.dbg.value</a>
				624	intrinsic. This intrinsic represents debug info for variables that are
				625	promoted to SSA values (typically by mem2reg or the -scalarrepl passes).</li>
Chris Lattner	acce85d	2008-02-10 07:46:44 +0000	[diff] [blame]	626
Chris Lattner	11b6611	2010-10-04 02:42:39 +0000	[diff] [blame]	627	<li>The JumpThreading pass is now much more aggressive about implied value
				628	relations, allowing it to thread conditions like "a == 4" when a is known to
				629	be 13 in one of the predecessors of a block. It does this in conjunction
				630	with the new LazyValueInfo analysis pass.</li>
				631	<li>The new RegionInfo analysis pass identifies single-entry single-exit regions
				632	in the CFG. You can play with it with the "opt -regions analyze" or
				633	"opt -view-regions" commands.</li>
Duncan Sands	30be9e4	2010-10-04 10:04:14 +0000	[diff] [blame]	634	<li>The loop optimizer has significantly improved strength reduction and analysis
Chris Lattner	11b6611	2010-10-04 02:42:39 +0000	[diff] [blame]	635	capabilities. Notably it is able to build on the trap value and signed
				636	integer overflow information to optimize <= and >= loops.</li>
				637	<li>The CallGraphSCCPassManager now has some basic support for iterating within
				638	an SCC when a optimizer devirtualizes a function call. This allows inlining
				639	through indirect call sites that are devirtualized by store-load forwarding
				640	and other optimizations.</li>
				641	<li>The new <A href="Passes.html#loweratomic">-loweratomic</a> pass is available
				642	to lower atomic instructions into their non-atomic form. This can be useful
				643	to optimize generic code that expects to run in a single-threaded
				644	environment.</li>
				645	</ul>
				646
				647	<!--
				648	<p>In addition to these features that are done in 2.8, there is preliminary
				649	support in the release for Type Based Alias Analysis
Chris Lattner	7d9b6b4	2010-10-02 21:59:30 +0000	[diff] [blame]	650	Preliminary work on TBAA but not usable in 2.8.
				651	New CorrelatedValuePropagation pass, not on by default in 2.8 yet.
Chris Lattner	11b6611	2010-10-04 02:42:39 +0000	[diff] [blame]	652	-->
Chris Lattner	917cc71	2009-03-02 02:37:32 +0000	[diff] [blame]	653
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	654	</div>
Chris Lattner	917cc71	2009-03-02 02:37:32 +0000	[diff] [blame]	655
Chris Lattner	0b83220	2008-06-08 02:45:07 +0000	[diff] [blame]	656	<!--=========================================================================-->
				657	<div class="doc_subsection">
Chris Lattner	4ba2b65	2010-09-30 16:31:33 +0000	[diff] [blame]	658	<a name="mc">MC Level Improvements</a>
				659	</div>
				660
				661	<div class="doc_text">
				662	<p>
Chris Lattner	7d9b6b4	2010-10-02 21:59:30 +0000	[diff] [blame]	663	The LLVM Machine Code (aka MC) subsystem was created to solve a number
Chris Lattner	4ba2b65	2010-09-30 16:31:33 +0000	[diff] [blame]	664	of problems in the realm of assembly, disassembly, object file format handling,
				665	and a number of other related areas that CPU instruction-set level tools work
Chris Lattner	7d9b6b4	2010-10-02 21:59:30 +0000	[diff] [blame]	666	in.</p>
				667
				668	<p>The MC subproject has made great leaps in LLVM 2.8. For example, support for
				669	directly writing .o files from LLC (and clang) now works reliably for
				670	darwin/x86[-64] (including inline assembly support) and the integrated
				671	assembler is turned on by default in Clang for these targets. This provides
				672	improved compile times among other things.</p>
				673
				674	<ul>
				675	<li>The entire compiler has converted over to using the MCStreamer assembler API
				676	instead of writing out a .s file textually.</li>
				677	<li>The "assembler parser" is far more mature than in 2.7, supporting a full
				678	complement of directives, now supports assembler macros, etc.</li>
				679	<li>The "assembler backend" has been completed, including support for relaxation
				680	relocation processing and all the other things that an assembler does.</li>
				681	<li>The MachO file format support is now fully functional and works.</li>
				682	<li>The MC disassembler now fully supports ARM and Thumb. ARM assembler support
				683	is still in early development though.</li>
				684	<li>The X86 MC assembler now supports the X86 AES and AVX instruction set.</li>
Chris Lattner	3bdcda1	2010-10-04 03:58:12 +0000	[diff] [blame]	685	<li>Work on ELF and COFF object files and ARM target support is well underway,
				686	but isn't useful yet in LLVM 2.8. Please contact the llvmdev mailing list
				687	if you're interested in this.</li>
Chris Lattner	7d9b6b4	2010-10-02 21:59:30 +0000	[diff] [blame]	688	</ul>
				689
				690	<p>For more information, please see the <a
Chris Lattner	4ba2b65	2010-09-30 16:31:33 +0000	[diff] [blame]	691	href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
				692	LLVM MC Project Blog Post</a>.
				693	</p>
				694
Chris Lattner	4ba2b65	2010-09-30 16:31:33 +0000	[diff] [blame]	695	</div>
				696
				697
Chris Lattner	4ba2b65	2010-09-30 16:31:33 +0000	[diff] [blame]	698	<!--=========================================================================-->
				699	<div class="doc_subsection">
Chris Lattner	511433e	2009-03-02 03:24:11 +0000	[diff] [blame]	700	<a name="codegen">Target Independent Code Generator Improvements</a>
Chris Lattner	0b83220	2008-06-08 02:45:07 +0000	[diff] [blame]	701	</div>
				702
				703	<div class="doc_text">
				704
Mikhail Glushenkov	f795ef0	2009-03-01 18:09:47 +0000	[diff] [blame]	705	<p>We have put a significant amount of work into the code generator
				706	infrastructure, which allows us to implement more aggressive algorithms and make
				707	it run faster:</p>
Chris Lattner	0b83220	2008-06-08 02:45:07 +0000	[diff] [blame]	708
				709	<ul>
Chris Lattner	3bdcda1	2010-10-04 03:58:12 +0000	[diff] [blame]	710	<li>The clang/gcc -momit-leaf-frame-pointer argument is now supported.</li>
				711	<li>The clang/gcc -ffunction-sections and -fdata-sections arguments are now
				712	supported on ELF targets (like GCC).</li>
				713	<li>The MachineCSE pass is now tuned and on by default. It eliminates common
				714	subexpressions that are exposed when lowering to machine instructions.</li>
				715	<li>The "local" register allocator was replaced by a new "fast" register
				716	allocator. This new allocator (which is often used at -O0) is substantially
				717	faster and produces better code than the old local register allocator.</li>
				718	<li>A new LLC "-regalloc=default" option is available, which automatically
				719	chooses a register allocator based on the -O optimization level.</li>
				720	<li>The common code generator code was modified to promote illegal argument and
				721	return value vectors to wider ones when possible instead of scalarizing
				722	them. For example, <3 x float> will now pass in one SSE register
				723	instead of 3 on X86. This generates substantially better code since the
				724	rest of the code generator was already expecting this.</li>
				725	<li>The code generator uses a new "COPY" machine instruction. This speeds up
				726	the code generator and eliminates the need for targets to implement the
				727	isMoveInstr hook. Also, the copyRegToReg hook was renamed to copyPhysReg
				728	and simplified.</li>
				729	<li>The code generator now has a "LocalStackSlotPass", which optimizes stack
				730	slot access for targets (like ARM) that have limited stack displacement
				731	addressing.</li>
				732	<li>A new "PeepholeOptimizer" is available, which eliminates sign and zero
				733	extends, and optimizes away compare instructions when the condition result
				734	is available from a previous instruction.</li>
				735	<li>Atomic operations now get legalized into simpler atomic operations if not
Duncan Sands	30be9e4	2010-10-04 10:04:14 +0000	[diff] [blame]	736	natively supported, easing the implementation burden on targets.</li>
Chris Lattner	b822f65	2010-10-04 16:46:07 +0000	[diff] [blame]	737	<li>We have added two new bottom-up pre-allocation register pressure aware schedulers:
				738	<ol>
				739	<li>The hybrid scheduler schedules aggressively to minimize schedule length when registers are available and avoid overscheduling in high pressure situations.</li>
				740	<li>The instruction-level-parallelism scheduler schedules for maximum ILP when registers are available and avoid overscheduling in high pressure situations.</li>
				741	</ol></li>
Chris Lattner	3bdcda1	2010-10-04 03:58:12 +0000	[diff] [blame]	742	<li>The tblgen type inference algorithm was rewritten to be more consistent and
				743	diagnose more target bugs. If you have an out-of-tree backend, you may
				744	find that it finds bugs in your target description. This support also
				745	allows limited support for writing patterns for instructions that return
				746	multiple results (e.g. a virtual register and a flag result). The
				747	'parallel' modifier in tblgen was removed, you should use the new support
				748	for multiple results instead.</li>
				749	<li>A new (experimental) "-rendermf" pass is available which renders a
				750	MachineFunction into HTML, showing live ranges and other useful
				751	details.</li>
Chris Lattner	7714c91	2010-10-04 04:39:25 +0000	[diff] [blame]	752	<li>The new SubRegIndex tablegen class allows subregisters to be indexed
				753	symbolically instead of numerically. If your target uses subregisters you
				754	will need to adapt to use SubRegIndex when you upgrade to 2.8.</li>
Chris Lattner	3bdcda1	2010-10-04 03:58:12 +0000	[diff] [blame]	755	<!-- SplitKit -->
Chris Lattner	7d9b6b4	2010-10-02 21:59:30 +0000	[diff] [blame]	756
Chris Lattner	3bdcda1	2010-10-04 03:58:12 +0000	[diff] [blame]	757	<li>The -fast-isel instruction selection path (used at -O0 on X86) was rewritten
				758	to work bottom-up on basic blocks instead of top down. This makes it
				759	slightly faster (because the MachineDCE pass is not needed any longer) and
				760	allows it to generate better code in some cases.</li>
Chris Lattner	7d9b6b4	2010-10-02 21:59:30 +0000	[diff] [blame]	761
Chris Lattner	8497764	2007-09-21 03:54:09 +0000	[diff] [blame]	762	</ul>
Chris Lattner	8497764	2007-09-21 03:54:09 +0000	[diff] [blame]	763	</div>
				764
Chris Lattner	917cc71	2009-03-02 02:37:32 +0000	[diff] [blame]	765	<!--=========================================================================-->
				766	<div class="doc_subsection">
				767	<a name="x86">X86-32 and X86-64 Target Improvements</a>
				768	</div>
				769
				770	<div class="doc_text">
Chris Lattner	7714c91	2010-10-04 04:39:25 +0000	[diff] [blame]	771	<p>New features and major changes in the X86 target include:
Chris Lattner	917cc71	2009-03-02 02:37:32 +0000	[diff] [blame]	772	</p>
				773
				774	<ul>
Chris Lattner	922d00f	2010-07-21 15:57:40 +0000	[diff] [blame]	775	<li>The X86 backend now supports holding X87 floating point stack values
				776	in registers across basic blocks, dramatically improving performance of code
Gabor Greif	9f45913	2010-10-04 17:03:49 +0000	[diff] [blame^]	777	that uses long double, and when targeting CPUs that don't support SSE.</li>
Chris Lattner	511433e	2009-03-02 03:24:11 +0000	[diff] [blame]	778
Chris Lattner	7714c91	2010-10-04 04:39:25 +0000	[diff] [blame]	779	<li>The X86 backend now uses a SSEDomainFix pass to optimize SSE operations. On
				780	Nehalem ("Core i7") and newer CPUs there is a 2 cycle latency penalty on
				781	using a register in a different domain than where it was defined. This pass
				782	optimizes away these stalls.</li>
Chris Lattner	7d9b6b4	2010-10-02 21:59:30 +0000	[diff] [blame]	783
Duncan Sands	30be9e4	2010-10-04 10:04:14 +0000	[diff] [blame]	784	<li>The X86 backend now promotes 16-bit integer operations to 32-bits when
Chris Lattner	7714c91	2010-10-04 04:39:25 +0000	[diff] [blame]	785	possible. This avoids 0x66 prefixes, which are slow on some
				786	microarchitectures and bloat the code on all of them.</li>
Chris Lattner	7d9b6b4	2010-10-02 21:59:30 +0000	[diff] [blame]	787
Chris Lattner	7714c91	2010-10-04 04:39:25 +0000	[diff] [blame]	788	<li>The X86 backend now supports the Microsoft "thiscall" calling convention,
				789	and a <a href="LangRef.html#callingconv">calling convention</a> to support
				790	<a href="#GHC">ghc</a>.</li>
Chris Lattner	7d9b6b4	2010-10-02 21:59:30 +0000	[diff] [blame]	791
Chris Lattner	7714c91	2010-10-04 04:39:25 +0000	[diff] [blame]	792	<li>The X86 backend supports a new "llvm.x86.int" intrinsic, which maps onto
				793	the X86 "int $42" and "int3" instructions.</li>
Chris Lattner	7d9b6b4	2010-10-02 21:59:30 +0000	[diff] [blame]	794
Chris Lattner	7714c91	2010-10-04 04:39:25 +0000	[diff] [blame]	795	<li>At the IR level, the <2 x float> datatype is now promoted and passed
Duncan Sands	30be9e4	2010-10-04 10:04:14 +0000	[diff] [blame]	796	around as a <4 x float> instead of being passed and returned as an MMX
Chris Lattner	7714c91	2010-10-04 04:39:25 +0000	[diff] [blame]	797	vector. If you have a frontend that uses this, please pass and return a
				798	<2 x i32> instead (using bitcasts).</li>
				799
				800	<li>When printing .s files in verbose assembly mode (the default for clang -S),
				801	the X86 backend now decodes X86 shuffle instructions and prints human
Gabor Greif	9f45913	2010-10-04 17:03:49 +0000	[diff] [blame^]	802	readable comments after the most inscrutable of them, e.g.:
Chris Lattner	7714c91	2010-10-04 04:39:25 +0000	[diff] [blame]	803
				804	<pre>
				805	insertps $113, %xmm3, %xmm0 <i># xmm0 = zero,xmm0[1,2],xmm3[1]</i>
				806	unpcklps %xmm1, %xmm0 <i># xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1]</i>
				807	pshufd $1, %xmm1, %xmm1 <i># xmm1 = xmm1[1,0,0,0]</i>
				808	</pre>
				809	</li>
Chris Lattner	7d9b6b4	2010-10-02 21:59:30 +0000	[diff] [blame]	810
Chris Lattner	917cc71	2009-03-02 02:37:32 +0000	[diff] [blame]	811	</ul>
				812
Chris Lattner	917cc71	2009-03-02 02:37:32 +0000	[diff] [blame]	813	</div>
Chris Lattner	8497764	2007-09-21 03:54:09 +0000	[diff] [blame]	814
				815	<!--=========================================================================-->
				816	<div class="doc_subsection">
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	817	<a name="ARM">ARM Target Improvements</a>
Chris Lattner	c441fb8	2009-03-01 02:30:21 +0000	[diff] [blame]	818	</div>
				819
				820	<div class="doc_text">
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	821	<p>New features of the ARM target include:
				822	</p>
Chris Lattner	c441fb8	2009-03-01 02:30:21 +0000	[diff] [blame]	823
				824	<ul>
Chris Lattner	7714c91	2010-10-04 04:39:25 +0000	[diff] [blame]	825	<li>The ARM backend now optimizes tail calls into jumps.</li>
				826	<li>Scheduling is improved through the new list-hybrid scheduler as well
				827	as through better modeling of structural hazards.</li>
				828	<li><a href="LangRef.html#int_fp16">Half float</a> instructions are now
				829	supported.</li>
				830	<li>NEON support has been improved to model instructions which operate onto
Duncan Sands	30be9e4	2010-10-04 10:04:14 +0000	[diff] [blame]	831	multiple consecutive registers more aggressively. This avoids lots of
Chris Lattner	7714c91	2010-10-04 04:39:25 +0000	[diff] [blame]	832	extraneous register copies.</li>
				833	<li>The ARM backend now uses a new "ARMGlobalMerge" pass, which merges several
				834	global variables into one, saving extra address computation (all the global
				835	variables can be accessed via same base address) and potentially reducing
				836	register pressure.</li>
Chris Lattner	c441fb8	2009-03-01 02:30:21 +0000	[diff] [blame]	837
Chris Lattner	7714c91	2010-10-04 04:39:25 +0000	[diff] [blame]	838	<li>The ARM has received many minor improvements and tweaks which lead to
				839	substantially better performance in a wide range of different scenarios.</li>
Chris Lattner	7d9b6b4	2010-10-02 21:59:30 +0000	[diff] [blame]	840
Chris Lattner	4eac924	2010-10-02 22:44:15 +0000	[diff] [blame]	841	<li>The ARM NEON intrinsics have been substantially reworked to reduce
				842	redundancy and improve code generation. Some of the major changes are:
				843	<ol>
				844	<li>
				845	All of the NEON load and store intrinsics (llvm.arm.neon.vld* and
				846	llvm.arm.neon.vst*) take an extra parameter to specify the alignment in bytes
				847	of the memory being accessed.
				848	</li>
				849	<li>
				850	The llvm.arm.neon.vaba intrinsic (vector absolute difference and
				851	accumulate) has been removed. This operation is now represented using
				852	the llvm.arm.neon.vabd intrinsic (vector absolute difference) followed by a
				853	vector add.
				854	</li>
				855	<li>
				856	The llvm.arm.neon.vabdl and llvm.arm.neon.vabal intrinsics (lengthening
Gabor Greif	9f45913	2010-10-04 17:03:49 +0000	[diff] [blame^]	857	vector absolute difference with and without accumulation) have been removed.
Chris Lattner	4eac924	2010-10-02 22:44:15 +0000	[diff] [blame]	858	They are represented using the llvm.arm.neon.vabd intrinsic (vector absolute
				859	difference) followed by a vector zero-extend operation, and for vabal,
				860	a vector add.
				861	</li>
				862	<li>
				863	The llvm.arm.neon.vmovn intrinsic has been removed. Calls of this intrinsic
				864	are now replaced by vector truncate operations.
				865	</li>
				866	<li>
				867	The llvm.arm.neon.vmovls and llvm.arm.neon.vmovlu intrinsics have been
				868	removed. They are now represented as vector sign-extend (vmovls) and
				869	zero-extend (vmovlu) operations.
				870	</li>
				871	<li>
				872	The llvm.arm.neon.vaddl, llvm.arm.neon.vaddw, llvm.arm.neon.vsubl*, and
				873	llvm.arm.neon.vsubw* intrinsics (lengthening vector add and subtract) have
				874	been removed. They are replaced by vector add and vector subtract operations
				875	where one (vaddw, vsubw) or both (vaddl, vsubl) of the operands are either
				876	sign-extended or zero-extended.
				877	</li>
				878	<li>
				879	The llvm.arm.neon.vmulls, llvm.arm.neon.vmullu, llvm.arm.neon.vmlal*, and
				880	llvm.arm.neon.vmlsl* intrinsics (lengthening vector multiply with and without
				881	accumulation and subtraction) have been removed. These operations are now
				882	represented as vector multiplications where the operands are either
				883	sign-extended or zero-extended, followed by a vector add for vmlal or a
				884	vector subtract for vmlsl. Note that the polynomial vector multiply
				885	intrinsic, llvm.arm.neon.vmullp, remains unchanged.
				886	</li>
				887	</ol>
Bob Wilson	5b2fb95	2010-09-13 17:37:55 +0000	[diff] [blame]	888	</li>
Chris Lattner	7714c91	2010-10-04 04:39:25 +0000	[diff] [blame]	889
Bob Wilson	e847277	2010-09-13 17:39:35 +0000	[diff] [blame]	890	</ul>
Chris Lattner	61358ab	2009-10-13 17:48:04 +0000	[diff] [blame]	891	</div>
Chris Lattner	c441fb8	2009-03-01 02:30:21 +0000	[diff] [blame]	892
Chris Lattner	77d29b1	2008-06-05 08:02:49 +0000	[diff] [blame]	893
				894	<!--=========================================================================-->
				895	<div class="doc_subsection">
Chris Lattner	f6662f9	2008-10-13 17:57:36 +0000	[diff] [blame]	896	<a name="changes">Major Changes and Removed Features</a>
				897	</div>
				898
				899	<div class="doc_text">
				900
Chris Lattner	eeb4da0	2008-10-13 22:06:31 +0000	[diff] [blame]	901	<p>If you're already an LLVM user or developer with out-of-tree changes based
Chris Lattner	922d00f	2010-07-21 15:57:40 +0000	[diff] [blame]	902	on LLVM 2.7, this section lists some "gotchas" that you may run into upgrading
Chris Lattner	eeb4da0	2008-10-13 22:06:31 +0000	[diff] [blame]	903	from the previous release.</p>
Chris Lattner	f6662f9	2008-10-13 17:57:36 +0000	[diff] [blame]	904
				905	<ul>
Chris Lattner	bb11771	2010-10-04 01:29:06 +0000	[diff] [blame]	906	<li>The build configuration machinery changed the output directory names. It
Duncan Sands	30be9e4	2010-10-04 10:04:14 +0000	[diff] [blame]	907	wasn't clear to many people that a "Release-Asserts" build was a release build
Chris Lattner	bb11771	2010-10-04 01:29:06 +0000	[diff] [blame]	908	without asserts. To make this more clear, "Release" does not include
				909	assertions and "Release+Asserts" does (likewise, "Debug" and
				910	"Debug+Asserts").</li>
				911	<li>The MSIL Backend was removed, it was unsupported and broken.</li>
				912	<li>The ABCD, SSI, and SCCVN passes were removed. These were not fully
				913	functional and their behavior has been or will be subsumed by the
				914	LazyValueInfo pass.</li>
				915	<li>The LLVM IR 'Union' feature was removed. While this is a desirable feature
				916	for LLVM IR to support, the existing implementation was half baked and
				917	barely useful. We'd really like anyone interested to resurrect the work and
				918	finish it for a future release.</li>
				919	<li>If you're used to reading .ll files, you'll probably notice that .ll file
				920	dumps don't produce #uses comments anymore. To get them, run a .bc file
				921	through "llvm-dis --show-annotations".</li>
Chris Lattner	11b6611	2010-10-04 02:42:39 +0000	[diff] [blame]	922	<li>Target triples are now stored in a normalized form, and all inputs from
				923	humans are expected to be normalized by Triple::normalize before being
				924	stored in a module triple or passed to another library.</li>
Chris Lattner	b7c85b4	2010-04-21 05:17:40 +0000	[diff] [blame]	925	</ul>
Chris Lattner	eeb4da0	2008-10-13 22:06:31 +0000	[diff] [blame]	926
Chris Lattner	bb11771	2010-10-04 01:29:06 +0000	[diff] [blame]	927
				928
Chris Lattner	eeb4da0	2008-10-13 22:06:31 +0000	[diff] [blame]	929	<p>In addition, many APIs have changed in this release. Some of the major LLVM
				930	API changes are:</p>
Chris Lattner	eeb4da0	2008-10-13 22:06:31 +0000	[diff] [blame]	931	<ul>
Chris Lattner	4eac924	2010-10-02 22:44:15 +0000	[diff] [blame]	932	<li>LLVM 2.8 changes the internal order of operands in <a
				933	href="http://llvm.org/doxygen/classllvm_1_1InvokeInst.html"><tt>InvokeInst</tt></a>
				934	and <a href="http://llvm.org/doxygen/classllvm_1_1CallInst.html"><tt>CallInst</tt></a>.
Chris Lattner	bb11771	2010-10-04 01:29:06 +0000	[diff] [blame]	935	To be portable across releases, please use the <tt>CallSite</tt> class and the
				936	high-level accessors, such as <tt>getCalledValue</tt> and
				937	<tt>setUnwindDest</tt>.
Chris Lattner	4eac924	2010-10-02 22:44:15 +0000	[diff] [blame]	938	</li>
				939	<li>
Chris Lattner	bb11771	2010-10-04 01:29:06 +0000	[diff] [blame]	940	You can no longer pass use_iterators directly to cast<> (and similar),
				941	because these routines tend to perform costly dereference operations more
				942	than once. You have to dereference the iterators yourself and pass them in.
Chris Lattner	4eac924	2010-10-02 22:44:15 +0000	[diff] [blame]	943	</li>
				944	<li>
Chris Lattner	bb11771	2010-10-04 01:29:06 +0000	[diff] [blame]	945	llvm.memcpy., llvm.memset., llvm.memmove.* intrinsics take an extra
				946	parameter now ("i1 isVolatile"), totaling 5 parameters, and the pointer
				947	operands are now address-space qualified.
Chris Lattner	4eac924	2010-10-02 22:44:15 +0000	[diff] [blame]	948	If you were creating these intrinsic calls and prototypes yourself (as opposed
Chris Lattner	bb11771	2010-10-04 01:29:06 +0000	[diff] [blame]	949	to using Intrinsic::getDeclaration), you can use
Gabor Greif	9f45913	2010-10-04 17:03:49 +0000	[diff] [blame^]	950	UpgradeIntrinsicFunction/UpgradeIntrinsicCall to be portable across releases.
Chris Lattner	4eac924	2010-10-02 22:44:15 +0000	[diff] [blame]	951	</li>
				952	<li>
				953	SetCurrentDebugLocation takes a DebugLoc now instead of a MDNode.
				954	Change your code to use
				955	SetCurrentDebugLocation(DebugLoc::getFromDILocation(...)).
				956	</li>
				957	<li>
Chris Lattner	4eac924	2010-10-02 22:44:15 +0000	[diff] [blame]	958	The <tt>RegisterPass</tt> and <tt>RegisterAnalysisGroup</tt> templates are
				959	considered deprecated, but continue to function in LLVM 2.8. Clients are
				960	strongly advised to use the upcoming <tt>INITIALIZE_PASS()</tt> and
				961	<tt>INITIALIZE_AG_PASS()</tt> macros instead.
Chris Lattner	4eac924	2010-10-02 22:44:15 +0000	[diff] [blame]	962	</li>
				963	<li>
				964	The constructor for the Triple class no longer tries to understand odd triple
				965	specifications. Frontends should ensure that they only pass valid triples to
				966	LLVM. The Triple::normalize utility method has been added to help front-ends
				967	deal with funky triples.
Chris Lattner	bb11771	2010-10-04 01:29:06 +0000	[diff] [blame]	968	</li>
				969
Chris Lattner	4eac924	2010-10-02 22:44:15 +0000	[diff] [blame]	970	<li>
				971	Some APIs got renamed:
				972	<ul>
Chris Lattner	bb11771	2010-10-04 01:29:06 +0000	[diff] [blame]	973	<li>llvm_report_error -> report_fatal_error</li>
				974	<li>llvm_install_error_handler -> install_fatal_error_handler</li>
				975	<li>llvm::DwarfExceptionHandling -> llvm::JITExceptionHandling</li>
				976	<li>VISIBILITY_HIDDEN -> LLVM_LIBRARY_VISIBILITY</li>
Chris Lattner	4eac924	2010-10-02 22:44:15 +0000	[diff] [blame]	977	</ul>
				978	</li>
				979
Devang Patel	b34dd13	2008-10-14 20:03:43 +0000	[diff] [blame]	980	</ul>
Chris Lattner	f6662f9	2008-10-13 17:57:36 +0000	[diff] [blame]	981
Chris Lattner	f6662f9	2008-10-13 17:57:36 +0000	[diff] [blame]	982	</div>
				983
				984
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	985	<!-- *********************************************************************** -->
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	986	<div class="doc_section">
				987	<a name="knownproblems">Known Problems</a>
				988	</div>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	989	<!-- *********************************************************************** -->
				990
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	991	<div class="doc_text">
				992
Mikhail Glushenkov	f795ef0	2009-03-01 18:09:47 +0000	[diff] [blame]	993	<p>This section contains significant known problems with the LLVM system,
Chris Lattner	e18b32e	2008-11-10 05:40:34 +0000	[diff] [blame]	994	listed by component. If you run into a problem, please check the <a
Chris Lattner	c463b27	2005-10-29 07:07:09 +0000	[diff] [blame]	995	href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner	5eccca4	2003-12-12 21:22:16 +0000	[diff] [blame]	996	there isn't already one.</p>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	997
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	998	</div>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	999
Chris Lattner	f5ee170	2004-03-14 02:03:02 +0000	[diff] [blame]	1000	<!-- ======================================================================= -->
				1001	<div class="doc_subsection">
				1002	<a name="experimental">Experimental features included with this release</a>
				1003	</div>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	1004
Chris Lattner	f5ee170	2004-03-14 02:03:02 +0000	[diff] [blame]	1005	<div class="doc_text">
				1006
Misha Brukman	6df9e2c	2004-05-12 21:46:05 +0000	[diff] [blame]	1007	<p>The following components of this LLVM release are either untested, known to
				1008	be broken or unreliable, or are in early development. These components should
				1009	not be relied on, and bugs should not be filed against them, but they may be
				1010	useful to some people. In particular, if you would like to work on one of these
Chris Lattner	2b659ef	2008-02-12 06:29:45 +0000	[diff] [blame]	1011	components, please contact us on the <a
				1012	href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattner	f5ee170	2004-03-14 02:03:02 +0000	[diff] [blame]	1013
				1014	<ul>
Chris Lattner	bb11771	2010-10-04 01:29:06 +0000	[diff] [blame]	1015	<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, PIC16, SystemZ
				1016	and XCore backends are experimental.</li>
Chris Lattner	7d9b6b4	2010-10-02 21:59:30 +0000	[diff] [blame]	1017	<li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets
				1018	other than darwin-i386 and darwin-x86_64.</li>
Chris Lattner	f5ee170	2004-03-14 02:03:02 +0000	[diff] [blame]	1019	</ul>
				1020
				1021	</div>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	1022
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	1023	<!-- ======================================================================= -->
				1024	<div class="doc_subsection">
Chris Lattner	2629922	2006-11-18 07:51:14 +0000	[diff] [blame]	1025	<a name="x86-be">Known problems with the X86 back-end</a>
John Criswell	c0c186d	2005-11-08 21:11:33 +0000	[diff] [blame]	1026	</div>
				1027
				1028	<div class="doc_text">
				1029
				1030	<ul>
Anton Korobeynikov	a6094be	2008-06-08 10:24:13 +0000	[diff] [blame]	1031	<li>The X86 backend does not yet support
				1032	all <a href="http://llvm.org/PR879">inline assembly that uses the X86
				1033	floating point stack</a>. It supports the 'f' and 't' constraints, but not
				1034	'u'.</li>
Duncan Sands	47eff2b	2008-06-08 19:38:43 +0000	[diff] [blame]	1035	<li>Win64 code generation wasn't widely tested. Everything should work, but we
John Criswell	524a5dd	2009-03-02 15:28:15 +0000	[diff] [blame]	1036	expect small issues to happen. Also, llvm-gcc cannot build the mingw64
Chris Lattner	914ce46	2010-04-22 06:28:20 +0000	[diff] [blame]	1037	runtime currently due to lack of support for the 'u' inline assembly
				1038	constraint and for X87 floating point inline assembly.</li>
Dan Gohman	8207ba9	2008-06-08 23:05:11 +0000	[diff] [blame]	1039	<li>The X86-64 backend does not yet support the LLVM IR instruction
Chris Lattner	914ce46	2010-04-22 06:28:20 +0000	[diff] [blame]	1040	<tt>va_arg</tt>. Currently, front-ends support variadic
Dan Gohman	8207ba9	2008-06-08 23:05:11 +0000	[diff] [blame]	1041	argument constructs on X86-64 by lowering them manually.</li>
Chris Lattner	2629922	2006-11-18 07:51:14 +0000	[diff] [blame]	1042	</ul>
				1043
				1044	</div>
				1045
				1046	<!-- ======================================================================= -->
				1047	<div class="doc_subsection">
				1048	<a name="ppc-be">Known problems with the PowerPC back-end</a>
				1049	</div>
				1050
				1051	<div class="doc_text">
				1052
				1053	<ul>
Nicolas Geoffray	e4285dc	2007-05-15 09:21:28 +0000	[diff] [blame]	1054	<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattner	57a460e	2007-05-23 04:39:32 +0000	[diff] [blame]	1055	compilation, and lacks support for debug information.</li>
Chris Lattner	2629922	2006-11-18 07:51:14 +0000	[diff] [blame]	1056	</ul>
				1057
				1058	</div>
				1059
				1060	<!-- ======================================================================= -->
				1061	<div class="doc_subsection">
Chris Lattner	f3e5bc6	2007-05-14 06:56:09 +0000	[diff] [blame]	1062	<a name="arm-be">Known problems with the ARM back-end</a>
				1063	</div>
				1064
				1065	<div class="doc_text">
				1066
				1067	<ul>
Chris Lattner	57a460e	2007-05-23 04:39:32 +0000	[diff] [blame]	1068	<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
Duncan Sands	c90d68b	2007-09-26 15:59:54 +0000	[diff] [blame]	1069	processors, thumb programs can crash or produce wrong
Chris Lattner	57a460e	2007-05-23 04:39:32 +0000	[diff] [blame]	1070	results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
John Criswell	524a5dd	2009-03-02 15:28:15 +0000	[diff] [blame]	1071	<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
Chris Lattner	f3e5bc6	2007-05-14 06:56:09 +0000	[diff] [blame]	1072	</li>
Chris Lattner	f3e5bc6	2007-05-14 06:56:09 +0000	[diff] [blame]	1073	</ul>
				1074
				1075	</div>
				1076
				1077	<!-- ======================================================================= -->
				1078	<div class="doc_subsection">
Chris Lattner	2629922	2006-11-18 07:51:14 +0000	[diff] [blame]	1079	<a name="sparc-be">Known problems with the SPARC back-end</a>
				1080	</div>
				1081
				1082	<div class="doc_text">
				1083
				1084	<ul>
John Criswell	524a5dd	2009-03-02 15:28:15 +0000	[diff] [blame]	1085	<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
Chris Lattner	2629922	2006-11-18 07:51:14 +0000	[diff] [blame]	1086	support the 64-bit SPARC ABI (-m64).</li>
				1087	</ul>
				1088
				1089	</div>
				1090
				1091	<!-- ======================================================================= -->
				1092	<div class="doc_subsection">
Bruno Cardoso Lopes	b7e1a4f	2008-10-25 14:56:26 +0000	[diff] [blame]	1093	<a name="mips-be">Known problems with the MIPS back-end</a>
				1094	</div>
				1095
				1096	<div class="doc_text">
				1097
				1098	<ul>
Bruno Cardoso Lopes	b7e1a4f	2008-10-25 14:56:26 +0000	[diff] [blame]	1099	<li>64-bit MIPS targets are not supported yet.</li>
				1100	</ul>
				1101
				1102	</div>
				1103
				1104	<!-- ======================================================================= -->
				1105	<div class="doc_subsection">
Chris Lattner	2629922	2006-11-18 07:51:14 +0000	[diff] [blame]	1106	<a name="alpha-be">Known problems with the Alpha back-end</a>
				1107	</div>
				1108
				1109	<div class="doc_text">
				1110
				1111	<ul>
				1112
				1113	<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
				1114	appropriate nops inserted to ensure restartability.</li>
				1115
John Criswell	c0c186d	2005-11-08 21:11:33 +0000	[diff] [blame]	1116	</ul>
				1117	</div>
				1118
Chris Lattner	2629922	2006-11-18 07:51:14 +0000	[diff] [blame]	1119	<!-- ======================================================================= -->
				1120	<div class="doc_subsection">
Chris Lattner	f3e5bc6	2007-05-14 06:56:09 +0000	[diff] [blame]	1121	<a name="c-be">Known problems with the C back-end</a>
Chris Lattner	2629922	2006-11-18 07:51:14 +0000	[diff] [blame]	1122	</div>
				1123
				1124	<div class="doc_text">
				1125
Chris Lattner	3016ee9	2010-09-29 05:34:42 +0000	[diff] [blame]	1126	<p>The C backend has numerous problems and is not being actively maintained.
				1127	Depending on it for anything serious is not advised.</p>
				1128
Chris Lattner	2629922	2006-11-18 07:51:14 +0000	[diff] [blame]	1129	<ul>
Chris Lattner	5733b27	2008-06-05 06:35:40 +0000	[diff] [blame]	1130	<li><a href="http://llvm.org/PR802">The C backend has only basic support for
				1131	inline assembly code</a>.</li>
Chris Lattner	725a0d8	2007-09-26 06:01:35 +0000	[diff] [blame]	1132	<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
				1133	C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
Gabor Greif	4906abe	2009-03-02 12:02:51 +0000	[diff] [blame]	1134	C++ code compiled with <tt>llc</tt> or native compilers.</li>
Duncan Sands	f74c0cc	2008-02-10 13:40:55 +0000	[diff] [blame]	1135	<li>The C backend does not support all exception handling constructs.</li>
Duncan Sands	50723a9	2009-02-25 11:51:54 +0000	[diff] [blame]	1136	<li>The C backend does not support arbitrary precision integers.</li>
Chris Lattner	2629922	2006-11-18 07:51:14 +0000	[diff] [blame]	1137	</ul>
				1138
				1139	</div>
John Criswell	c0c186d	2005-11-08 21:11:33 +0000	[diff] [blame]	1140
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	1141
				1142	<!-- ======================================================================= -->
				1143	<div class="doc_subsection">
Chris Lattner	3016ee9	2010-09-29 05:34:42 +0000	[diff] [blame]	1144	<a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	1145	</div>
Chris Lattner	47588f9	2003-10-02 05:07:23 +0000	[diff] [blame]	1146
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	1147	<div class="doc_text">
Chris Lattner	c5d658a	2006-03-03 00:34:26 +0000	[diff] [blame]	1148
Chris Lattner	3016ee9	2010-09-29 05:34:42 +0000	[diff] [blame]	1149	<p>llvm-gcc is generally very stable for the C family of languages. The only
				1150	major language feature of GCC not supported by llvm-gcc is the
				1151	<tt>__builtin_apply</tt> family of builtins. However, some extensions
				1152	are only supported on some targets. For example, trampolines are only
				1153	supported on some targets (these are used when you take the address of a
				1154	nested function).</p>
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	1155
Chris Lattner	3016ee9	2010-09-29 05:34:42 +0000	[diff] [blame]	1156	<p>Fortran support generally works, but there are still several unresolved bugs
				1157	in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
				1158	tools/gfortran component for details. Note that llvm-gcc is missing major
				1159	Fortran performance work in the frontend and library that went into GCC after
				1160	4.2. If you are interested in Fortran, we recommend that you consider using
				1161	<a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	1162
Duncan Sands	3af9633	2010-10-04 10:06:56 +0000	[diff] [blame]	1163	<p>The llvm-gcc 4.2 Ada compiler has basic functionality, but is no longer being
				1164	actively maintained. If you are interested in Ada, we recommend that you
				1165	consider using <a href="#dragonegg">dragonegg</a> instead.</p>
Chris Lattner	2b659ef	2008-02-12 06:29:45 +0000	[diff] [blame]	1166	</div>
				1167
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	1168	<!-- *********************************************************************** -->
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	1169	<div class="doc_section">
				1170	<a name="additionalinfo">Additional Information</a>
				1171	</div>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	1172	<!-- *********************************************************************** -->
				1173
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	1174	<div class="doc_text">
				1175
Chris Lattner	416db10	2005-05-16 17:13:10 +0000	[diff] [blame]	1176	<p>A wide variety of additional information is available on the <a
Chris Lattner	b4b0ce7	2007-05-18 00:44:29 +0000	[diff] [blame]	1177	href="http://llvm.org">LLVM web page</a>, in particular in the <a
				1178	href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencer	669ed45	2007-07-09 08:04:31 +0000	[diff] [blame]	1179	contains versions of the API documentation which is up-to-date with the
				1180	Subversion version of the source code.
Misha Brukman	109d9e8	2005-03-30 19:14:24 +0000	[diff] [blame]	1181	You can access versions of these documents specific to this release by going
				1182	into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	1183
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	1184	<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattner	c463b27	2005-10-29 07:07:09 +0000	[diff] [blame]	1185	us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner	5eccca4	2003-12-12 21:22:16 +0000	[diff] [blame]	1186	lists</a>.</p>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	1187
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	1188	</div>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	1189
				1190	<!-- *********************************************************************** -->
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	1191
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	1192	<hr>
Misha Brukman	2061e89	2003-11-22 01:23:39 +0000	[diff] [blame]	1193	<address>
Misha Brukman	38847d5	2003-12-21 22:53:21 +0000	[diff] [blame]	1194	<a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman	4440870	2008-12-11 17:34:48 +0000	[diff] [blame]	1195	src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman	2061e89	2003-11-22 01:23:39 +0000	[diff] [blame]	1196	<a href="http://validator.w3.org/check/referer"><img
Misha Brukman	4440870	2008-12-11 17:34:48 +0000	[diff] [blame]	1197	src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukman	2061e89	2003-11-22 01:23:39 +0000	[diff] [blame]	1198
Chris Lattner	b4b0ce7	2007-05-18 00:44:29 +0000	[diff] [blame]	1199	<a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	1200	Last modified: $Date$
Misha Brukman	2061e89	2003-11-22 01:23:39 +0000	[diff] [blame]	1201	</address>
Chris Lattner	79c3fe1	2003-10-02 04:57:28 +0000	[diff] [blame]	1202
Misha Brukman	500bc30	2003-11-22 00:38:41 +0000	[diff] [blame]	1203	</body>
				1204	</html>