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			948 lines
		
	
	
		
			32 KiB
		
	
	
	
		
			HTML
		
	
	
	
	
	
| <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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|                       "http://www.w3.org/TR/html4/strict.dtd">
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| <html>
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| <head>
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|   <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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|   <link rel="stylesheet" href="llvm.css" type="text/css">
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|   <title>LLVM 3.0 Release Notes</title>
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| </head>
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| <body>
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| 
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| <h1>LLVM 3.0 Release Notes</h1>
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| 
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| <img align=right src="http://llvm.org/img/DragonSmall.png"
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|     width="136" height="136" alt="LLVM Dragon Logo">
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| 
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| <ol>
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|   <li><a href="#intro">Introduction</a></li>
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|   <li><a href="#subproj">Sub-project Status Update</a></li>
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|   <li><a href="#externalproj">External Projects Using LLVM 3.0</a></li>
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|   <li><a href="#whatsnew">What's New in LLVM 3.0?</a></li>
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|   <li><a href="GettingStarted.html">Installation Instructions</a></li>
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|   <li><a href="#knownproblems">Known Problems</a></li>
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|   <li><a href="#additionalinfo">Additional Information</a></li>
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| </ol>
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| 
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| <div class="doc_author">
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|   <p>Written by the <a href="http://llvm.org/">LLVM Team</a></p>
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| </div>
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| 
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| <!--
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| <h1 style="color:red">These are in-progress notes for the upcoming LLVM 3.0
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| release.<br>
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| You may prefer the
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| <a href="http://llvm.org/releases/2.9/docs/ReleaseNotes.html">LLVM 2.9
 | |
| Release Notes</a>.</h1>
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|  -->
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| 
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| <!-- *********************************************************************** -->
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| <h2>
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|   <a name="intro">Introduction</a>
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| </h2>
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| <!-- *********************************************************************** -->
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| 
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| <div>
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| 
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| <p>This document contains the release notes for the LLVM Compiler
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| Infrastructure, release 3.0.  Here we describe the status of LLVM, including
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| major improvements from the previous release and significant known problems.
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| All LLVM releases may be downloaded from the <a
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| href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
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| 
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| <p>For more information about LLVM, including information about the latest
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| release, please check out the <a href="http://llvm.org/">main LLVM
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| web site</a>.  If you have questions or comments, the <a
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| href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's
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| Mailing List</a> is a good place to send them.</p>
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| 
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| <p>Note that if you are reading this file from a Subversion checkout or the
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| main LLVM web page, this document applies to the <i>next</i> release, not the
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| current one.  To see the release notes for a specific release, please see the
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| <a href="http://llvm.org/releases/">releases page</a>.</p>
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| 
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| </div>
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|    
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| <!-- Features that need text if they're finished for 3.1:
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|   ARM EHABI
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|   combiner-aa?
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|   strong phi elim
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|   loop dependence analysis
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|   CorrelatedValuePropagation
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|   lib/Transforms/IPO/MergeFunctions.cpp => consider for 3.1.
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|  -->
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|  
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| <!-- *********************************************************************** -->
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| <h2>
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|   <a name="subproj">Sub-project Status Update</a>
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| </h2>
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| <!-- *********************************************************************** -->
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| 
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| <div>
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| <p>
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| The LLVM 3.0 distribution currently consists of code from the core LLVM
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| repository (which roughly includes the LLVM optimizers, code generators
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| and supporting tools), the Clang repository and the llvm-gcc repository.  In
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| addition to this code, the LLVM Project includes other sub-projects that are in
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| development.  Here we include updates on these subprojects.
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| </p>
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| 
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| <!--=========================================================================-->
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| <h3>
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| <a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
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| </h3>
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| 
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| <div>
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| 
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| <p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
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| C++, and Objective-C languages. Clang aims to provide a better user experience
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| through expressive diagnostics, a high level of conformance to language
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| standards, fast compilation, and low memory use. Like LLVM, Clang provides a
 | |
| modular, library-based architecture that makes it suitable for creating or
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| integrating with other development tools. Clang is considered a
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| production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
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| (32- and 64-bit), and for darwin/arm targets.</p>
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| 
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| <p>In the LLVM 3.0 time-frame, the Clang team has made many improvements:</p>
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|   
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| <p>If Clang rejects your code but another compiler accepts it, please take a
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| look at the <a href="http://clang.llvm.org/compatibility.html">language
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| compatibility</a> guide to make sure this is not intentional or a known issue.
 | |
| </p>
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| 
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| </div>
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| 
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| <!--=========================================================================-->
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| <h3>
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| <a name="dragonegg">DragonEgg: GCC front-ends, LLVM back-end</a>
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| </h3>
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| 
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| <div>
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| <p>
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| <a href="http://dragonegg.llvm.org/">DragonEgg</a> is a
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| <a href="http://gcc.gnu.org/wiki/plugins">gcc plugin</a> that replaces GCC's
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| optimizers and code generators with LLVM's.
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| Currently it requires a patched version of gcc-4.5.
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| The plugin can target the x86-32 and x86-64 processor families and has been
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| used successfully on the Darwin, FreeBSD and Linux platforms.
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| The Ada, C, C++ and Fortran languages work well.
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| The plugin is capable of compiling plenty of Obj-C, Obj-C++ and Java but it is
 | |
| not known whether the compiled code actually works or not!
 | |
| </p>
 | |
| 
 | |
| <p>
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| The 3.0 release has the following notable changes:
 | |
| <ul>
 | |
| <!--
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| <li></li>
 | |
| -->
 | |
| </ul>
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| 
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>
 | |
| <a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
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| </h3>
 | |
| 
 | |
| <div>
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| <p>
 | |
| The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
 | |
| is a simple library that provides an implementation of the low-level
 | |
| target-specific hooks required by code generation and other runtime components.
 | |
| For example, when compiling for a 32-bit target, converting a double to a 64-bit
 | |
| unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
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| function. The compiler-rt library provides highly optimized implementations of
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| this and other low-level routines (some are 3x faster than the equivalent
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| libgcc routines).</p>
 | |
| 
 | |
| <p>In the LLVM 3.0 timeframe,</p>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>
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| <a name="lldb">LLDB: Low Level Debugger</a>
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| </h3>
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| 
 | |
| <div>
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| <p>
 | |
| <a href="http://lldb.llvm.org/">LLDB</a> is a brand new member of the LLVM
 | |
| umbrella of projects. LLDB is a next generation, high-performance debugger. It
 | |
| is built as a set of reusable components which highly leverage existing
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| libraries in the larger LLVM Project, such as the Clang expression parser, the
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| LLVM disassembler and the LLVM JIT.</p>
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| 
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| <p>
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| LLDB is has advanced by leaps and bounds in the 3.0 timeframe.  It is
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| dramatically more stable and useful, and includes both a new <a 
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| href="http://lldb.llvm.org/tutorial.html">tutorial</a> and a <a
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| href="http://lldb.llvm.org/lldb-gdb.html">side-by-side comparison with 
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| GDB</a>.</p>
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| 
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| </div>
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| 
 | |
| <!--=========================================================================-->
 | |
| <h3>
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| <a name="libc++">libc++: C++ Standard Library</a>
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| </h3>
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| 
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| <div>
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| <p>
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| <a href="http://libcxx.llvm.org/">libc++</a> is another new member of the LLVM
 | |
| family.  It is an implementation of the C++ standard library, written from the
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| ground up to specifically target the forthcoming C++'0X standard and focus on
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| delivering great performance.</p>
 | |
| 
 | |
| <p>
 | |
| In the LLVM 3.0 timeframe,</p>
 | |
|   
 | |
| <p>
 | |
| Like compiler_rt, libc++ is now <a href="DeveloperPolicy.html#license">dual
 | |
|   licensed</a> under the MIT and UIUC license, allowing it to be used more
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|   permissively.
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| </p>
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| 
 | |
| </div>
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| 
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>
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| <a name="LLBrowse">LLBrowse: IR Browser</a>
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| </h3>
 | |
| 
 | |
| <div>
 | |
| <p>
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| <a href="http://llvm.org/svn/llvm-project/llbrowse/trunk/doc/LLBrowse.html">
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|   LLBrowse</a> is an interactive viewer for LLVM modules. It can load any LLVM
 | |
|   module and displays its contents as an expandable tree view, facilitating an
 | |
|   easy way to inspect types, functions, global variables, or metadata nodes. It
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|   is fully cross-platform, being based on the popular wxWidgets GUI toolkit.
 | |
| </p>
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>
 | |
| <a name="vmkit">VMKit</a>
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| </h3>
 | |
| 
 | |
| <div>
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| <p>The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation
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|   of a Java Virtual Machine (Java VM or JVM) that uses LLVM for static and
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|   just-in-time compilation. As of LLVM 3.0, VMKit now supports generational
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|   garbage collectors. The garbage collectors are provided by the MMTk framework,
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|   and VMKit can be configured to use one of the numerous implemented collectors
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|   of MMTk.
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| </p>
 | |
| </div>
 | |
|   
 | |
|   
 | |
| <!--=========================================================================-->
 | |
| <!--
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| <h3>
 | |
| <a name="klee">KLEE: A Symbolic Execution Virtual Machine</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
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| <p>
 | |
| <a href="http://klee.llvm.org/">KLEE</a> is a symbolic execution framework for
 | |
| programs in LLVM bitcode form. KLEE tries to symbolically evaluate "all" paths
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| through the application and records state transitions that lead to fault
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| states. This allows it to construct testcases that lead to faults and can even
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| be used to verify some algorithms.
 | |
| </p>
 | |
| 
 | |
| <p>UPDATE!</p>
 | |
| </div>-->
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!-- *********************************************************************** -->
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| <h2>
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|   <a name="externalproj">External Open Source Projects Using LLVM 3.0</a>
 | |
| </h2>
 | |
| <!-- *********************************************************************** -->
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| 
 | |
| <div>
 | |
| 
 | |
| <p>An exciting aspect of LLVM is that it is used as an enabling technology for
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|    a lot of other language and tools projects.  This section lists some of the
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|    projects that have already been updated to work with LLVM 3.0.</p>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>Crack Programming Language</h3>
 | |
| 
 | |
| <div>
 | |
| <p>
 | |
| <a href="http://code.google.com/p/crack-language/">Crack</a> aims to provide the
 | |
| ease of development of a scripting language with the performance of a compiled
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| language. The language derives concepts from C++, Java and Python, incorporating
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| object-oriented programming, operator overloading and strong typing.</p>
 | |
| </div>
 | |
|   
 | |
|   
 | |
| <!--=========================================================================-->
 | |
| <h3>TTA-based Codesign Environment (TCE)</h3>
 | |
|   
 | |
| <div>
 | |
| <p>TCE is a toolset for designing application-specific processors (ASP) based on
 | |
| the Transport triggered architecture (TTA). The toolset provides a complete
 | |
| co-design flow from C/C++ programs down to synthesizable VHDL and parallel
 | |
| program binaries. Processor customization points include the register files,
 | |
| function units, supported operations, and the interconnection network.</p>
 | |
|   
 | |
| <p>TCE uses Clang and LLVM for C/C++ language support, target independent
 | |
| optimizations and also for parts of code generation. It generates new LLVM-based
 | |
| code generators "on the fly" for the designed TTA processors and loads them in
 | |
| to the compiler backend as runtime libraries to avoid per-target recompilation
 | |
| of larger parts of the compiler chain.</p>
 | |
| </div>
 | |
| 
 | |
| 
 | |
|   
 | |
| <!--=========================================================================-->
 | |
| <h3>PinaVM</h3>
 | |
|   
 | |
| <div>
 | |
| <p><a href="http://gitorious.org/pinavm/pages/Home">PinaVM</a> is an open
 | |
| source, <a href="http://www.systemc.org/">SystemC</a> front-end. Unlike many
 | |
| other front-ends, PinaVM actually executes the elaboration of the
 | |
| program analyzed using LLVM's JIT infrastructure. It later enriches the
 | |
| bitcode with SystemC-specific information.</p>
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>Pure</h3>
 | |
|   
 | |
| <div>
 | |
| <p><a href="http://pure-lang.googlecode.com/">Pure</a> is an
 | |
|   algebraic/functional
 | |
|   programming language based on term rewriting. Programs are collections
 | |
|   of equations which are used to evaluate expressions in a symbolic
 | |
|   fashion. The interpreter uses LLVM as a backend to JIT-compile Pure
 | |
|   programs to fast native code. Pure offers dynamic typing, eager and lazy
 | |
|   evaluation, lexical closures, a hygienic macro system (also based on
 | |
|   term rewriting), built-in list and matrix support (including list and
 | |
|   matrix comprehensions) and an easy-to-use interface to C and other
 | |
|   programming languages (including the ability to load LLVM bitcode
 | |
|   modules, and inline C, C++, Fortran and Faust code in Pure programs if
 | |
|   the corresponding LLVM-enabled compilers are installed).</p>
 | |
|   
 | |
| <p>Pure version 0.47 has been tested and is known to work with LLVM 3.0
 | |
|   (and continues to work with older LLVM releases >= 2.5).</p>
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3 id="icedtea">IcedTea Java Virtual Machine Implementation</h3>
 | |
| 
 | |
| <div>
 | |
| <p>
 | |
| <a href="http://icedtea.classpath.org/wiki/Main_Page">IcedTea</a> provides a
 | |
| harness to build OpenJDK using only free software build tools and to provide
 | |
| replacements for the not-yet free parts of OpenJDK.  One of the extensions that
 | |
| IcedTea provides is a new JIT compiler named <a
 | |
| href="http://icedtea.classpath.org/wiki/ZeroSharkFaq">Shark</a> which uses LLVM
 | |
| to provide native code generation without introducing processor-dependent
 | |
| code.
 | |
| </p>
 | |
| 
 | |
| <p> OpenJDK 7 b112, IcedTea6 1.9 and IcedTea7 1.13 and later have been tested
 | |
| and are known to work with LLVM 3.0 (and continue to work with older LLVM
 | |
| releases >= 2.6 as well).</p>
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>Glasgow Haskell Compiler (GHC)</h3>
 | |
|   
 | |
| <div>
 | |
| <p>GHC is an open source, state-of-the-art programming suite for Haskell,
 | |
| a standard lazy functional programming language. It includes an
 | |
| optimizing static compiler generating good code for a variety of
 | |
| platforms, together with an interactive system for convenient, quick
 | |
| development.</p>
 | |
| 
 | |
| <p>In addition to the existing C and native code generators, GHC 7.0 now
 | |
| supports an LLVM code generator. GHC supports LLVM 2.7 and later.</p>
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>Polly - Polyhedral optimizations for LLVM</h3>
 | |
|   
 | |
| <div>
 | |
| <p>Polly is a project that aims to provide advanced memory access optimizations
 | |
| to better take advantage of SIMD units, cache hierarchies, multiple cores or
 | |
| even vector accelerators for LLVM. Built around an abstract mathematical
 | |
| description based on Z-polyhedra, it provides the infrastructure to develop
 | |
| advanced optimizations in LLVM and to connect complex external optimizers. In
 | |
| its first year of existence Polly already provides an exact value-based
 | |
| dependency analysis as well as basic SIMD and OpenMP code generation support.
 | |
| Furthermore, Polly can use PoCC(Pluto) an advanced optimizer for data-locality
 | |
| and parallelism.</p>
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>Rubinius</h3>
 | |
| 
 | |
| <div>
 | |
|   <p><a href="http://github.com/evanphx/rubinius">Rubinius</a> is an environment
 | |
|   for running Ruby code which strives to write as much of the implementation in
 | |
|   Ruby as possible. Combined with a bytecode interpreting VM, it uses LLVM to
 | |
|   optimize and compile ruby code down to machine code. Techniques such as type
 | |
|   feedback, method inlining, and deoptimization are all used to remove dynamism
 | |
|   from ruby execution and increase performance.</p>
 | |
| </div>
 | |
| 
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>
 | |
| <a name="FAUST">FAUST Real-Time Audio Signal Processing Language</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| <p>
 | |
| <a href="http://faust.grame.fr">FAUST</a> is a compiled language for real-time
 | |
| audio signal processing. The name FAUST stands for Functional AUdio STream. Its
 | |
| programming model combines two approaches: functional programming and block
 | |
| diagram composition. In addition with the C, C++, JAVA output formats, the
 | |
| Faust compiler can now generate LLVM bitcode, and works with LLVM 2.7-3.0.</p>
 | |
| 
 | |
| </div>
 | |
|   
 | |
| </div>
 | |
| 
 | |
| <!-- *********************************************************************** -->
 | |
| <h2>
 | |
|   <a name="whatsnew">What's New in LLVM 3.0?</a>
 | |
| </h2>
 | |
| <!-- *********************************************************************** -->
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <p>This release includes a huge number of bug fixes, performance tweaks and
 | |
| minor improvements.  Some of the major improvements and new features are listed
 | |
| in this section.
 | |
| </p>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>
 | |
| <a name="majorfeatures">Major New Features</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <p>LLVM 3.0 includes several major new capabilities:</p>
 | |
| 
 | |
| <ul>
 | |
| 
 | |
| <!--
 | |
| <li></li>
 | |
| -->
 | |
|   
 | |
| </ul>
 | |
|   
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>
 | |
| <a name="coreimprovements">LLVM IR and Core Improvements</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| <p>LLVM IR has several new features for better support of new targets and that
 | |
| expose new optimization opportunities:</p>
 | |
| 
 | |
| <ul>
 | |
| <!--
 | |
| <li></li>
 | |
| -->
 | |
| </ul>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>
 | |
| <a name="optimizer">Optimizer Improvements</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <p>In addition to a large array of minor performance tweaks and bug fixes, this
 | |
| release includes a few major enhancements and additions to the optimizers:</p>
 | |
| 
 | |
| <ul>
 | |
| <!--
 | |
| <li></li>
 | |
| -->
 | |
| </li>
 | |
|   
 | |
| </ul>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>
 | |
| <a name="mc">MC Level Improvements</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| <p>
 | |
| The LLVM Machine Code (aka MC) subsystem was created to solve a number
 | |
| of problems in the realm of assembly, disassembly, object file format handling,
 | |
| and a number of other related areas that CPU instruction-set level tools work
 | |
| in.</p>
 | |
| 
 | |
| <ul>
 | |
| <!--
 | |
| <li></li>
 | |
| -->
 | |
| </ul>
 | |
| 
 | |
| <p>For more information, please see the <a
 | |
| href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
 | |
| LLVM MC Project Blog Post</a>.
 | |
| </p>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>
 | |
| <a name="codegen">Target Independent Code Generator Improvements</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <p>We have put a significant amount of work into the code generator
 | |
| infrastructure, which allows us to implement more aggressive algorithms and make
 | |
| it run faster:</p>
 | |
| 
 | |
| <ul>
 | |
| <!--
 | |
| <li></li>
 | |
| -->
 | |
| </ul>
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>
 | |
| <a name="x86">X86-32 and X86-64 Target Improvements</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| <p>New features and major changes in the X86 target include:
 | |
| </p>
 | |
| 
 | |
| <ul>
 | |
| <li>The CRC32 intrinsics have been renamed.  The intrinsics were previously
 | |
|   @llvm.x86.sse42.crc32.[8|16|32] and @llvm.x86.sse42.crc64.[8|64].  They have
 | |
|   been renamed to @llvm.x86.sse42.crc32.32.[8|16|32] and 
 | |
|   @llvm.x86.sse42.crc32.64.[8|64].</li>
 | |
| 
 | |
| </ul>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>
 | |
| <a name="ARM">ARM Target Improvements</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| <p>New features of the ARM target include:
 | |
| </p>
 | |
| 
 | |
| <ul>
 | |
| <!--
 | |
| <li></li>
 | |
| -->
 | |
| </ul>
 | |
| </div>
 | |
|   
 | |
| <!--=========================================================================-->
 | |
| <h3>
 | |
| <a name="OtherTS">Other Target Specific Improvements</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| <ul>
 | |
| <!--
 | |
| <li></li>
 | |
| -->
 | |
| </ul>
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>
 | |
| <a name="changes">Major Changes and Removed Features</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <p>If you're already an LLVM user or developer with out-of-tree changes based on
 | |
|    LLVM 2.9, this section lists some "gotchas" that you may run into upgrading
 | |
|    from the previous release.</p>
 | |
| 
 | |
| <ul>
 | |
|   <li>The <code>LLVMC</code> front end code was removed while separating
 | |
|       out language independence.</li>
 | |
|   <li>The <code>LowerSetJmp</code> pass wasn't used effectively by any
 | |
|       target and has been removed.</li>
 | |
|   <li>The old <code>TailDup</code> pass was not used in the standard pipeline
 | |
|       and was unable to update ssa form, so it has been removed.
 | |
|   <li>The syntax of volatile loads and stores in IR has been changed to
 | |
|       "<code>load volatile</code>"/"<code>store volatile</code>".  The old
 | |
|       syntax ("<code>volatile load</code>"/"<code>volatile store</code>")
 | |
|       is still accepted, but is now considered deprecated.</li>
 | |
| </ul>
 | |
| 
 | |
| <h4>Windows (32-bit)</h4>
 | |
| <div>
 | |
| <ul>
 | |
|   <li>On Win32(MinGW32 and MSVC), Windows 2000 will not be supported.
 | |
|       Windows XP or higher is required.</li>
 | |
| </ul>
 | |
| </div>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!--=========================================================================-->
 | |
| <h3>
 | |
| <a name="api_changes">Internal API Changes</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <p>In addition, many APIs have changed in this release.  Some of the major
 | |
|    LLVM API changes are:</p>
 | |
| 
 | |
| <ul>
 | |
| <li>The biggest and most pervasive change is that llvm::Type's are no longer
 | |
|     returned or accepted as 'const' values.  Instead, just pass around non-const
 | |
|     Type's.</li>
 | |
|   
 | |
| <li><code>PHINode::reserveOperandSpace</code> has been removed. Instead, you
 | |
|   must specify how many operands to reserve space for when you create the
 | |
|   PHINode, by passing an extra argument into <code>PHINode::Create</code>.</li>
 | |
| 
 | |
| <li>PHINodes no longer store their incoming BasicBlocks as operands. Instead,
 | |
|   the list of incoming BasicBlocks is stored separately, and can be accessed
 | |
|   with new functions <code>PHINode::block_begin</code>
 | |
|   and <code>PHINode::block_end</code>.</li>
 | |
| 
 | |
| <li>Various functions now take an <code>ArrayRef</code> instead of either a pair
 | |
|   of pointers (or iterators) to the beginning and end of a range, or a pointer
 | |
|   and a length. Others now return an <code>ArrayRef</code> instead of a
 | |
|   reference to a <code>SmallVector</code> or <code>std::vector</code>. These
 | |
|   include:
 | |
| <ul>
 | |
| <!-- Please keep this list sorted. -->
 | |
| <li><code>CallInst::Create</code></li>
 | |
| <li><code>ComputeLinearIndex</code> (in <code>llvm/CodeGen/Analysis.h</code>)</li>
 | |
| <li><code>ConstantArray::get</code></li>
 | |
| <li><code>ConstantExpr::getExtractElement</code></li>
 | |
| <li><code>ConstantExpr::getGetElementPtr</code></li>
 | |
| <li><code>ConstantExpr::getInBoundsGetElementPtr</code></li>
 | |
| <li><code>ConstantExpr::getIndices</code></li>
 | |
| <li><code>ConstantExpr::getInsertElement</code></li>
 | |
| <li><code>ConstantExpr::getWithOperands</code></li>
 | |
| <li><code>ConstantFoldCall</code> (in <code>llvm/Analysis/ConstantFolding.h</code>)</li>
 | |
| <li><code>ConstantFoldInstOperands</code> (in <code>llvm/Analysis/ConstantFolding.h</code>)</li>
 | |
| <li><code>ConstantVector::get</code></li>
 | |
| <li><code>DIBuilder::createComplexVariable</code></li>
 | |
| <li><code>DIBuilder::getOrCreateArray</code></li>
 | |
| <li><code>ExtractValueInst::Create</code></li>
 | |
| <li><code>ExtractValueInst::getIndexedType</code></li>
 | |
| <li><code>ExtractValueInst::getIndices</code></li>
 | |
| <li><code>FindInsertedValue</code> (in <code>llvm/Analysis/ValueTracking.h</code>)</li>
 | |
| <li><code>gep_type_begin</code> (in <code>llvm/Support/GetElementPtrTypeIterator.h</code>)</li>
 | |
| <li><code>gep_type_end</code> (in <code>llvm/Support/GetElementPtrTypeIterator.h</code>)</li>
 | |
| <li><code>GetElementPtrInst::Create</code></li>
 | |
| <li><code>GetElementPtrInst::CreateInBounds</code></li>
 | |
| <li><code>GetElementPtrInst::getIndexedType</code></li>
 | |
| <li><code>InsertValueInst::Create</code></li>
 | |
| <li><code>InsertValueInst::getIndices</code></li>
 | |
| <li><code>InvokeInst::Create</code></li>
 | |
| <li><code>IRBuilder::CreateCall</code></li>
 | |
| <li><code>IRBuilder::CreateExtractValue</code></li>
 | |
| <li><code>IRBuilder::CreateGEP</code></li>
 | |
| <li><code>IRBuilder::CreateInBoundsGEP</code></li>
 | |
| <li><code>IRBuilder::CreateInsertValue</code></li>
 | |
| <li><code>IRBuilder::CreateInvoke</code></li>
 | |
| <li><code>MDNode::get</code></li>
 | |
| <li><code>MDNode::getIfExists</code></li>
 | |
| <li><code>MDNode::getTemporary</code></li>
 | |
| <li><code>MDNode::getWhenValsUnresolved</code></li>
 | |
| <li><code>SimplifyGEPInst</code> (in <code>llvm/Analysis/InstructionSimplify.h</code>)</li>
 | |
| <li><code>TargetData::getIndexedOffset</code></li>
 | |
| </ul></li>
 | |
| 
 | |
| <li>All forms of <code>StringMap::getOrCreateValue</code> have been remove
 | |
|   except for the one which takes a <code>StringRef</code>.</li>
 | |
| 
 | |
| <li>The <code>LLVMBuildUnwind</code> function from the C API was removed. The
 | |
|     LLVM <code>unwind</code> instruction has been deprecated for a long time and
 | |
|     isn't used by the current front-ends. So this was removed during the
 | |
|     exception handling rewrite.</li>
 | |
| 
 | |
| <li>The <code>LLVMAddLowerSetJmpPass</code> function from the C API was removed
 | |
|     because the <code>LowerSetJmp</code> pass was removed.</li>
 | |
| 
 | |
| <li>The <code>DIBuilder</code> interface used by front ends to encode debugging 
 | |
|     information in the LLVM IR now expects clients to use <code>DIBuilder::finalize()</code>
 | |
|     at the end of translation unit to complete debugging information encoding.</li>
 | |
| 
 | |
| <li>The way the type system works has been rewritten: <code>PATypeHolder</code>
 | |
| and <code>OpaqueType</code> are gone, and all APIs deal with <code>Type*</code>
 | |
| instead of <code>const Type*</code>.
 | |
| If you need to create recursive structures, then create a named structure,
 | |
| and use <code>setBody()</code> when all its elements are built.
 | |
| Type merging and refining is gone too: named structures are not
 | |
| merged with other structures, even if their layout is identical.
 | |
| (of course anonymous structures are still uniqued by layout).
 | |
| </li>
 | |
| 
 | |
| <li>TargetSelect.h moved to Support/ from Target/</li>
 | |
| 
 | |
| <li>UpgradeIntrinsicCall no longer upgrades pre-2.9 intrinsic calls
 | |
| (for example <code>llvm.memset.i32</code>).</li>
 | |
| 
 | |
| <li>It is mandatory to initialize all out-of-tree passes too and their dependencies now with
 | |
| <code>INITIALIZE_PASS{BEGIN,END,}</code> and <code>INITIALIZE_{PASS,AG}_DEPENDENCY</code>.</li>
 | |
| 
 | |
| </ul>
 | |
| </div>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!-- *********************************************************************** -->
 | |
| <h2>
 | |
|   <a name="knownproblems">Known Problems</a>
 | |
| </h2>
 | |
| <!-- *********************************************************************** -->
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <p>This section contains significant known problems with the LLVM system,
 | |
| listed by component.  If you run into a problem, please check the <a
 | |
| href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
 | |
| there isn't already one.</p>
 | |
| 
 | |
| <!-- ======================================================================= -->
 | |
| <h3>
 | |
|   <a name="experimental">Experimental features included with this release</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <p>The following components of this LLVM release are either untested, known to
 | |
| be broken or unreliable, or are in early development.  These components should
 | |
| not be relied on, and bugs should not be filed against them, but they may be
 | |
| useful to some people.  In particular, if you would like to work on one of these
 | |
| components, please contact us on the <a
 | |
| href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
 | |
| 
 | |
| <ul>
 | |
| <li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, PTX, SystemZ
 | |
|     and XCore backends are experimental.</li>
 | |
| <li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets
 | |
|     other than darwin and ELF X86 systems.</li>
 | |
|     
 | |
| </ul>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!-- ======================================================================= -->
 | |
| <h3>
 | |
|   <a name="x86-be">Known problems with the X86 back-end</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <ul>
 | |
|   <li>The X86 backend does not yet support
 | |
|     all <a href="http://llvm.org/PR879">inline assembly that uses the X86
 | |
|     floating point stack</a>.  It supports the 'f' and 't' constraints, but not
 | |
|     'u'.</li>
 | |
|   <li>The X86-64 backend does not yet support the LLVM IR instruction
 | |
|       <tt>va_arg</tt>. Currently, front-ends support variadic
 | |
|       argument constructs on X86-64 by lowering them manually.</li>
 | |
|   <li>Windows x64 (aka Win64) code generator has a few issues.
 | |
|     <ul>
 | |
|       <li>llvm-gcc cannot build the mingw-w64 runtime currently
 | |
|        due to lack of support for the 'u' inline assembly
 | |
|        constraint and for X87 floating point inline assembly.</li>
 | |
|       <li>On mingw-w64, you will see unresolved symbol <tt>__chkstk</tt>
 | |
|        due to <a href="http://llvm.org/bugs/show_bug.cgi?id=8919">Bug 8919</a>.
 | |
|        It is fixed in <a href="http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20110321/118499.html">r128206</a>.</li>
 | |
|       <li>Miss-aligned MOVDQA might crash your program. It is due to
 | |
|        <a href="http://llvm.org/bugs/show_bug.cgi?id=9483">Bug 9483</a>,
 | |
|        lack of handling aligned internal globals.</li>
 | |
|       </ul>
 | |
|   </li>
 | |
| 
 | |
| </ul>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!-- ======================================================================= -->
 | |
| <h3>
 | |
|   <a name="ppc-be">Known problems with the PowerPC back-end</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <ul>
 | |
| <li>The Linux PPC32/ABI support needs testing for the interpreter and static
 | |
| compilation, and lacks support for debug information.</li>
 | |
| </ul>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!-- ======================================================================= -->
 | |
| <h3>
 | |
|   <a name="arm-be">Known problems with the ARM back-end</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <ul>
 | |
| <li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
 | |
| processors, thumb programs can crash or produce wrong
 | |
| results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
 | |
| <li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
 | |
| </li>
 | |
| </ul>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!-- ======================================================================= -->
 | |
| <h3>
 | |
|   <a name="sparc-be">Known problems with the SPARC back-end</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <ul>
 | |
| <li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
 | |
|     support the 64-bit SPARC ABI (-m64).</li>
 | |
| </ul>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!-- ======================================================================= -->
 | |
| <h3>
 | |
|   <a name="mips-be">Known problems with the MIPS back-end</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <ul>
 | |
| <li>64-bit MIPS targets are not supported yet.</li>
 | |
| </ul>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!-- ======================================================================= -->
 | |
| <h3>
 | |
|   <a name="alpha-be">Known problems with the Alpha back-end</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <ul>
 | |
| 
 | |
| <li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
 | |
| appropriate nops inserted to ensure restartability.</li>
 | |
| 
 | |
| </ul>
 | |
| </div>
 | |
| 
 | |
| <!-- ======================================================================= -->
 | |
| <h3>
 | |
|   <a name="c-be">Known problems with the C back-end</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <p>The C backend has numerous problems and is not being actively maintained.
 | |
| Depending on it for anything serious is not advised.</p>
 | |
| 
 | |
| <ul>
 | |
| <li><a href="http://llvm.org/PR802">The C backend has only basic support for
 | |
|     inline assembly code</a>.</li>
 | |
| <li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
 | |
|     C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
 | |
|     C++ code compiled with <tt>llc</tt> or native compilers.</li>
 | |
| <li>The C backend does not support all exception handling constructs.</li>
 | |
| <li>The C backend does not support arbitrary precision integers.</li>
 | |
| </ul>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| 
 | |
| <!-- ======================================================================= -->
 | |
| <h3>
 | |
|   <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
 | |
| </h3>
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <p><b>LLVM 3.0 will be the last release of llvm-gcc.</b></p>
 | |
| 
 | |
| <p>llvm-gcc is generally very stable for the C family of languages.  The only
 | |
|    major language feature of GCC not supported by llvm-gcc is the
 | |
|    <tt>__builtin_apply</tt> family of builtins.   However, some extensions
 | |
|    are only supported on some targets.  For example, trampolines are only
 | |
|    supported on some targets (these are used when you take the address of a
 | |
|    nested function).</p>
 | |
| 
 | |
| <p>Fortran support generally works, but there are still several unresolved bugs
 | |
|    in <a href="http://llvm.org/bugs/">Bugzilla</a>.  Please see the
 | |
|    tools/gfortran component for details.  Note that llvm-gcc is missing major
 | |
|    Fortran performance work in the frontend and library that went into GCC after
 | |
|    4.2.  If you are interested in Fortran, we recommend that you consider using
 | |
|    <a href="#dragonegg">dragonegg</a> instead.</p>
 | |
| 
 | |
| <p>The llvm-gcc 4.2 Ada compiler has basic functionality, but is no longer being
 | |
| actively maintained.  If you are interested in Ada, we recommend that you
 | |
| consider using <a href="#dragonegg">dragonegg</a> instead.</p>
 | |
| </div>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!-- *********************************************************************** -->
 | |
| <h2>
 | |
|   <a name="additionalinfo">Additional Information</a>
 | |
| </h2>
 | |
| <!-- *********************************************************************** -->
 | |
| 
 | |
| <div>
 | |
| 
 | |
| <p>A wide variety of additional information is available on the <a
 | |
| href="http://llvm.org/">LLVM web page</a>, in particular in the <a
 | |
| href="http://llvm.org/docs/">documentation</a> section.  The web page also
 | |
| contains versions of the API documentation which is up-to-date with the
 | |
| Subversion version of the source code.
 | |
| You can access versions of these documents specific to this release by going
 | |
| into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
 | |
| 
 | |
| <p>If you have any questions or comments about LLVM, please feel free to contact
 | |
| us via the <a href="http://llvm.org/docs/#maillist"> mailing
 | |
| lists</a>.</p>
 | |
| 
 | |
| </div>
 | |
| 
 | |
| <!-- *********************************************************************** -->
 | |
| 
 | |
| <hr>
 | |
| <address>
 | |
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|   src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
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|   src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
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| 
 | |
|   <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
 | |
|   Last modified: $Date$
 | |
| </address>
 | |
| 
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| </body>
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| </html>
 |