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1049 lines
38 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 2.6 Release Notes</title>
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</head>
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<body>
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<div class="doc_title">LLVM 2.6 Release Notes</div>
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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 2.6</a></li>
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<li><a href="#whatsnew">What's New in LLVM 2.6?</a></li>
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<li><a href="GettingStarted.html">Installation Instructions</a></li>
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<li><a href="#portability">Portability and Supported Platforms</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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<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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<div class="doc_section">
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<a name="intro">Introduction</a>
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</div>
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<!-- *********************************************************************** -->
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<div class="doc_text">
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<p>This document contains the release notes for the LLVM Compiler
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Infrastructure, release 2.6. 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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<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://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's Mailing
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List</a> is a good place to send them.</p>
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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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</div>
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<!--
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Almost dead code.
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include/llvm/Analysis/LiveValues.h => Dan
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lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8.
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llvm/Analysis/PointerTracking.h => Edwin wants this, consider for 2.8.
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-->
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|
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<!-- Unfinished features in 2.6:
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gcc plugin.
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strong phi elim
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variable debug info for optimized code
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postalloc scheduler: anti dependence breaking, hazard recognizer?
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metadata
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loop dependence analysis
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ELF Writer? How stable?
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<li>PostRA scheduler improvements, ARM adoption (David Goodwin).</li>
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-->
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<!-- for announcement email:
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Logo web page.
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llvm devmtg
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compiler_rt
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klee web page at klee.llvm.org
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Many new papers added to /pubs/
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Mention gcc plugin.
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-->
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<!-- *********************************************************************** -->
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<div class="doc_section">
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<a name="subproj">Sub-project Status Update</a>
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</div>
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<!-- *********************************************************************** -->
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<div class="doc_text">
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<p>
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The LLVM 2.6 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 — and the llvm-gcc repository. In addition to this
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code, the LLVM Project includes other sub-projects that are in development. The
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two which are the most actively developed are the <a href="#clang">Clang
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Project</a> and the <a href="#vmkit">VMKit Project</a>.
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</p>
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</div>
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<!--=========================================================================-->
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<div class="doc_subsection">
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<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
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</div>
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<div class="doc_text">
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<p><b>UPDATE!</b> The <a href="http://clang.llvm.org/">Clang project</a> is an effort to build
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a set of new 'LLVM native' front-end technologies for the LLVM optimizer and
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code generator. While Clang is not included in the LLVM 2.6 release, it is
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continuing to make major strides forward in all areas. Its C and Objective-C
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parsing and code generation support is now very solid. For example, it is
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capable of successfully building many real-world applications for X86-32
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and X86-64,
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including the <a href="http://wiki.freebsd.org/BuildingFreeBSDWithClang">FreeBSD
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kernel</a> and <a href="http://gcc.gnu.org/gcc-4.2/">gcc 4.2</a>. C++ is also
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making <a href="http://clang.llvm.org/cxx_status.html">incredible progress</a>,
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and work on templates has recently started. If you are
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interested in fast compiles and good diagnostics, we encourage you to try it out
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by <a href="http://clang.llvm.org/get_started.html">building from mainline</a>
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and reporting any issues you hit to the <a
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href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">Clang front-end mailing
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list</a>.</p>
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<p>In the LLVM 2.6 time-frame, the Clang team has made many improvements:</p>
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<ul>
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<li>Something wonderful!</li>
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<li>AuroraUX / FreeBSD & OpenBSD Toolchain support.</li>
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<li>Many many bugs are fixed and many features have been added.</li>
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</ul>
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</div>
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<!--=========================================================================-->
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<div class="doc_subsection">
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<a name="clangsa">Clang Static Analyzer</a>
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</div>
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<div class="doc_text">
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<p><b>UPDATE!</b> Previously announced in the 2.4 and 2.5 LLVM releases, the Clang project also
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includes an early stage static source code analysis tool for <a
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href="http://clang.llvm.org/StaticAnalysis.html">automatically finding bugs</a>
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in C and Objective-C programs. The tool performs a growing set of checks to find
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bugs that occur on a specific path within a program.</p>
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<p>In the LLVM 2.6 time-frame there have been many significant improvements to
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XYZ.</p>
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<p>The set of checks performed by the static analyzer continues to expand, and
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future plans for the tool include full source-level inter-procedural analysis
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and deeper checks such as buffer overrun detection. There are many opportunities
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to extend and enhance the static analyzer, and anyone interested in working on
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this project is encouraged to get involved!</p>
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</div>
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|
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<!--=========================================================================-->
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<div class="doc_subsection">
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<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
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</div>
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<div class="doc_text">
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<p>
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<b>UPDATE!</b>
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The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
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a JVM and a CLI Virtual Machines (Microsoft .NET is an
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implementation of the CLI) using the Just-In-Time compiler of LLVM.</p>
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<p>Following LLVM 2.6, VMKit has its XYZ release that you can find on its
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<a href="http://vmkit.llvm.org/releases/">webpage</a>. The release includes
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bug fixes, cleanup and new features. The major changes are:</p>
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<ul>
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<li>Something wonderful!</li>
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</ul>
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</div>
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<!--=========================================================================-->
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<div class="doc_subsection">
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<a name="mc">llvm-mc: Machine Code Toolkit</a>
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</div>
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<div class="doc_text">
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<p>
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<b>UPDATE!</b>
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blah
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MC:
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MCSection, MCAsmInfo
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MCInstPrinter did it make it in?
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MCInst (X86 using it so far)
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Rewrite of X86 GV selection logic: TargetOperand flags on ExternalSymbol, GV, etc operands.
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Can parse and re-print out an darwin-x86 .s file.
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TargetLoweringObjectFile, MCSectionKind
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Verrrry early start of a macho writer.
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</p>
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</div>
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|
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<!-- *********************************************************************** -->
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<div class="doc_section">
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<a name="externalproj">External Projects Using LLVM 2.6</a>
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</div>
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<!-- *********************************************************************** -->
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<!--=========================================================================-->
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<div class="doc_subsection">
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<a name="Rubinius">Rubinius</a>
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</div>
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<div class="doc_text">
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<p><a href="http://github.com/evanphx/rubinius">Rubinius</a> is an environment
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for running Ruby code which strives to write as much of the core class
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implementation in Ruby as possible. Combined with a bytecode interpreting VM, it
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uses LLVM to optimize and compile ruby code down to machine code. Techniques
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such as type feedback, method inlining, and uncommon traps are all used to
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remove dynamism from ruby execution and increase performance.</p>
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<p>Since LLVM 2.5, Rubinius has made several major leaps forward, implementing
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a counter based JIT, type feedback, and speculative method inlining.
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</p>
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</div>
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<!--=========================================================================-->
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<div class="doc_subsection">
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<a name="macruby">MacRuby</a>
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</div>
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<div class="doc_text">
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<p>
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<a href="http://macruby.org">MacRuby</a> is an implementation of Ruby on top of
|
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core Mac OS X technologies, such as the Objective-C common runtime and garbage
|
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collector, and the CoreFoundation framework. It is principally developed by
|
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Apple and aims at enabling the creation of full-fledged Mac OS X applications.
|
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</p>
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<p>
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MacRuby uses LLVM for optimization passes, JIT and AOT compilation of Ruby
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expressions. It also uses zero-cost DWARF exceptions to implement Ruby exception
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handling.</p>
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</div>
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<!--=========================================================================-->
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<div class="doc_subsection">
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<a name="pure">Pure</a>
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</div>
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<div class="doc_text">
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<p>
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<a href="http://pure-lang.googlecode.com/">Pure</a>
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is an algebraic/functional programming language based on term rewriting.
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Programs are collections of equations which are used to evaluate expressions in
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a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation,
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lexical closures, a hygienic macro system (also based on term rewriting),
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built-in list and matrix support (including list and matrix comprehensions) and
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an easy-to-use C interface. The interpreter uses LLVM as a backend to
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JIT-compile Pure programs to fast native code.</p>
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<p>Pure versions 0.31 and later have been tested and are known to work with
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LLVM 2.6 (and continue to work with older LLVM releases >= 2.3 as well).
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</p>
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</div>
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<!--=========================================================================-->
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<div class="doc_subsection">
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<a name="ldc">LLVM D Compiler</a>
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</div>
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<div class="doc_text">
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<p>
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<b>UPDATE!</b>
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<a href="http://www.dsource.org/projects/ldc">LDC</a> is an implementation of
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the D Programming Language using the LLVM optimizer and code generator.
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The LDC project works great with the LLVM 2.6 release. General improvements in
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this
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cycle have included new inline asm constraint handling, better debug info
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support, general bugfixes, and better x86-64 support. This has allowed
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some major improvements in LDC, getting us much closer to being as
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fully featured as the original DMD compiler from DigitalMars.
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</p>
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</div>
|
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|
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<!--=========================================================================-->
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<div class="doc_subsection">
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<a name="RoadsendPHP">Roadsend PHP</a>
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</div>
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<div class="doc_text">
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<p>
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<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
|
|
source implementation of the PHP programming
|
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language that uses LLVM for its optimizer, JIT, and static compiler. This is a
|
|
reimplementation of an earlier project that is now based on LLVM.</p>
|
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</div>
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<!--=========================================================================-->
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<div class="doc_subsection">
|
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<a name="Unladen Swallow">Unladen Swallow</a>
|
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</div>
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|
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<div class="doc_text">
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<p>
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<b>UPDATE!</b>
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<a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
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branch of <a href="http://python.org/">Python</a> intended to be fully
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compatible and significantly faster. It uses LLVM's optimization passes and JIT
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compiler.</p>
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</div>
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|
|
|
|
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<!-- *********************************************************************** -->
|
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<div class="doc_section">
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<a name="whatsnew">What's New in LLVM 2.6?</a>
|
|
</div>
|
|
<!-- *********************************************************************** -->
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<div class="doc_text">
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<p>This release includes a huge number of bug fixes, performance tweaks, and
|
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minor improvements. Some of the major improvements and new features are listed
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in this section.
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</p>
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</div>
|
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|
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<!--=========================================================================-->
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<div class="doc_subsection">
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<a name="majorfeatures">Major New Features</a>
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</div>
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<div class="doc_text">
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<p>LLVM 2.6 includes several major new capabilities:</p>
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<ul>
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<li>Support for debug line numbers when optimization enabled</li>
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<li>gold lto plugin</li>
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<li>New MSP430 and SystemZ backends.</li>
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<li>New BlackFin backend.</li>
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<li>LLVMContext, llvm_start_multithreaded: ProgrammersManual.html#threading</li>
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<li>klee web page at klee.llvm.org</li>
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<li>FileCheck</li>
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<li>New compiler-rt project.</li>
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<li>LLVM 2.6 includes a brand new experimental LLVM bindings to the Ada2005 programming language.</li>
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</ul>
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</div>
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<!--=========================================================================-->
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<div class="doc_subsection">
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<a name="coreimprovements">LLVM IR and Core Improvements</a>
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</div>
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<div class="doc_text">
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<p>LLVM IR has several new features that are used by our existing front-ends and
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can be useful if you are writing a front-end for LLVM:</p>
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<ul>
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<li>Getelementpr instruction now allows any integer type for array/pointer indexes.</li>
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<li>Inbounds for GEP</li>
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<li>NSW/NUW/exact div</li>
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<li>LSR promotes int induction variables to 64-bit on 64-bit targets, major perf boost for numerical code.</li>
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<li>LSR now analyzes pointer expressions (e.g. getelementptrs), not just integers.</li>
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<li>new linkage types linkonce_odr, weak_odr, linker_private, and available_externally.</li>
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<li>New fadd, fsub, fmul instructions and classes. </li>
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<li>Target intrinsics can now return multiple results.</li>
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</ul>
|
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</div>
|
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<!--=========================================================================-->
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<div class="doc_subsection">
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<a name="optimizer">Optimizer Improvements</a>
|
|
</div>
|
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<div class="doc_text">
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<p>In addition to a large array of bug fixes and minor performance tweaks, this
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release includes a few major enhancements and additions to the optimizers:</p>
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<ul>
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<li>SRoA improvements for vector unions, memset, arbitrary weird bitfield accesses etc. It now produces "strange" sized integers.</li>
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<li>Inliner reuse stack space when inlining arrays?</li>
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|
<li>Enabled GVN Load PRE.</li>
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<li>New Static Single Information (SSI) construction pass (not used by anything yet, experimental).</li>
|
|
</li>
|
|
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="codegen">Target Independent Code Generator Improvements</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>We have put a significant amount of work into the code generator
|
|
infrastructure, which allows us to implement more aggressive algorithms and make
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|
it run faster:</p>
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|
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<ul>
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|
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<li> -asm-verbose now prints location info (with -g) and loop nest info.</li>
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|
<li>Tblgen now supports multiclass inheritance and a number of new string and
|
|
list operations like !(subst), !(foreach), !car, !cdr, !null, !if, !cast.
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|
These make the .td files more expressive and allow more aggressive factoring
|
|
of duplication across instruction patterns.</li>
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|
<li>New MachineVerifier pass.</li>
|
|
<li>Machine LICM, hoists things like constant pool loads, loads from readonly stubs, vector constant synthesization code, etc.</li>
|
|
<li>Machine Sinking</li>
|
|
<li>target-specific intrinsics (r63765)</li>
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|
<li>Regalloc improvements for commuting, various spiller peephole optimizations, cross-class coalescing.</li>
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|
<li><tt>llc -enable-value-prop</tt>, propagation of value info (sign/zero ext info) from one MBB to another</li>
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|
<li>Regalloc hints for allocation stuff: Evan r73381/r73671. Finished/enabled?</li>
|
|
<li>Stack slot coloring for register spills (denser stack frames)</li>
|
|
<li>SelectionDAGS: New BuildVectorSDNode (r65296), and ISD::VECTOR_SHUFFLE (r69952 / PR2957)</li>
|
|
<li>Experimental support for shrink wrapping support in PEI.</li>
|
|
</ul>
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="x86">X86-32 and X86-64 Target Improvements</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>New features of the X86 target include:
|
|
</p>
|
|
|
|
<ul>
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|
|
|
<li>Preliminary support for addrspace 256 -> GS, 257 -> FS, known problems: CodeGenerator.html#x86_memory</li>
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|
<li>Support for softfloat modes, typically used by OS kernels.</li>
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|
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|
<li>X86-64: better modeling of implicit zero extensions, eliminates a lot of redundant zexts</li>
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|
<li>X86-64 TLS support for local exec and initial exec.</li>
|
|
<li>Better modeling of H registerts as subregs.</li>
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|
<li>Vector icmp/fcmp now work with SSE codegen.</li>
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|
<li>SSE 4.2 support.</li>
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|
<li>all global variable reference logic is now in ClassifyGlobalReference.</li>
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|
</li>
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|
</ul>
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|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="pic16">PIC16 Target Improvements</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>New features of the PIC16 target include:
|
|
</p>
|
|
|
|
<ul>
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|
<li>Support for floating-point, indirect function calls, and
|
|
passing/returning aggregate types to functions.
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|
<li>The code generator is able to generate debug info into output COFF files.
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|
<li>Support for placing an object into a specific section or at a specific
|
|
address in memory.</li>
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|
</ul>
|
|
|
|
<p>Things not yet supported:</p>
|
|
|
|
<ul>
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|
<li>Variable arguments.</li>
|
|
<li>Interrupts/programs.</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="ARM">ARM Target Improvements</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>New features of the ARM target include:
|
|
</p>
|
|
|
|
<ul>
|
|
|
|
<li>Preliminary support for processors, such as the Cortex-A8 and Cortex-A9,
|
|
that implement version v7-A of the ARM architecture. The ARM backend now
|
|
supports both the Thumb2 and Advanced SIMD (Neon) instruction sets. The
|
|
AAPCS-VFP "hard float" calling conventions are also supported with the
|
|
<tt>-float-abi=hard</tt> flag. These features are still somewhat experimental
|
|
and subject to change. The Neon intrinsics, in particular, may change in future
|
|
releases of LLVM.
|
|
</li>
|
|
|
|
ARM AAPCS-VFP hard float ABI is supported.
|
|
ARM calling convention code is now tblgen generated instead of manual.
|
|
ARM: NEON support. neonfp for doing single precision fp with neon instead of VFP.
|
|
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="OtherTarget">Other Target Specific Improvements</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>New features of other targets include:
|
|
</p>
|
|
|
|
<ul>
|
|
<li>Add support for the PowerPC 64-bit SVR4 ABI.</li>
|
|
<li>Mips now supports O32 Calling Convention.</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="newapis">New Useful APIs</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<ul>
|
|
<li>New EngineBuilder class for creating JITs: r76276</li>
|
|
New PrettyStackTrace, crashes of llvm tools should give some indication of what the compiler was doing at the time of the crash (e.g. running a pass), and print out command line arguments.
|
|
StringRef class, Twine class.
|
|
New WeakVH and AssertingVH and CallbackVH classes.
|
|
New llvm/ADT/Triple class.
|
|
llvm_report_error() error handling API (llvm/Support/ErrorHandling.h)
|
|
New llvm/System/Atomic.h, llvm/System/RWMutex.h for portable atomic ops, rw locks.
|
|
New SourceMgr, SMLoc classes for simple parsers with caret diagnostics and #include support, (used by
|
|
tablegen, llvm-mc, the .ll parser, FileCheck, etc)
|
|
|
|
<ul>
|
|
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="otherimprovements">Other Improvements and New Features</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<p>Other miscellaneous features include:</p>
|
|
|
|
<ul>
|
|
<li>interpreter + libffi</li>
|
|
<li> JIT now supports generating more than 16M of code.</li>
|
|
<li>Users can now <a
|
|
href="http://llvm.org/doxygen/classllvm_1_1ExecutionEngine.html#fcd2b4b92ca38812ca31640b0da14927">register</a>
|
|
a <a href="http://llvm.org/doxygen/classllvm_1_1JITEventListener.html">JITEventListener</a>
|
|
to receive callbacks when the JIT emits or frees machine code. The
|
|
OProfile support uses this mechanism.</li>
|
|
JIT support for oprofile (r75279), configure with --with-oprofile. Now we get line # and function info for JIT'd functions.
|
|
|
|
<li>Profile info improvements by Andreas Neustifter.</li>
|
|
<li>Many extensions to the C APIs.</li>
|
|
|
|
<li>LLVMC:
|
|
|
|
* Dynamic plugins now work on Windows.
|
|
* New option property: init. Makes possible to provide default values for
|
|
options defined in plugins (interface to cl::init).
|
|
* New example: Skeleton, shows how to create a standalone LLVMC-based driver.
|
|
* New example: mcc16, a driver for the PIC16 toolchain.</li>
|
|
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
|
|
<!--=========================================================================-->
|
|
<div class="doc_subsection">
|
|
<a name="changes">Major Changes and Removed Features</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>If you're already an LLVM user or developer with out-of-tree changes based
|
|
on LLVM 2.5, this section lists some "gotchas" that you may run into upgrading
|
|
from the previous release.</p>
|
|
|
|
<ul>
|
|
|
|
<li>The Itanium (IA64) backend has been removed. It was not supported and
|
|
bitrotted.</li>
|
|
<li>The BigBlock register allocator has been removed, it also bitrotted.</li>
|
|
<li>The C Backend (-march=c) is no longer considered part of the LLVM release
|
|
criteria. We still want it to work, but no one is maintaining it and it lacks
|
|
support for arbitrary precision integers and other important IR features.</li>
|
|
</ul>
|
|
|
|
LLVM build now builds all libraries as .a files instead of some
|
|
libraries as relinked .o files. This requires some APIs like
|
|
InitializeAllTargets.h. TargetRegistry!
|
|
|
|
|
|
|
|
|
|
<p>In addition, many APIs have changed in this release. Some of the major LLVM
|
|
API changes are:</p>
|
|
|
|
|
|
API Cleanup:
|
|
no use of hash_set/hash_map, no more llvm::OStream
|
|
Use raw_ostream for everything, killed off llvm/Streams.h and DOUT
|
|
|
|
<ul>
|
|
<li>LLVM's global uniquing tables for <tt>Type</tt>s and <tt>Constant</tt>s have
|
|
been privatized into members of an <tt>LLVMContext</tt>. A number of APIs
|
|
now take an <tt>LLVMContext</tt> as a parameter. To smooth the transition
|
|
for clients that will only ever use a single context, the new
|
|
<tt>getGlobalContext()</tt> API can be used to access a default global
|
|
context which can be passed in any and all cases where a context is
|
|
required.
|
|
<li>The <tt>getABITypeSize</tt> methods are now called <tt>getAllocSize</tt>.</li>
|
|
<li>The <tt>Add</tt>, <tt>Sub</tt>, and <tt>Mul</tt> operators are no longer
|
|
overloaded for floating-point types. Floating-point addition, subtraction,
|
|
and multiplication are now represented with new operators <tt>FAdd</tt>,
|
|
<tt>FSub</tt>, and <tt>FMul</tt>. In the <tt>IRBuilder</tt> API,
|
|
<tt>CreateAdd</tt>, <tt>CreateSub</tt>, <tt>CreateMul</tt>, and
|
|
<tt>CreateNeg</tt> should only be used for integer arithmetic now;
|
|
<tt>CreateFAdd</tt>, <tt>CreateFSub</tt>, <tt>CreateFMul</tt>, and
|
|
<tt>CreateFNeg</tt> should now be used for floating-point arithmetic.</li>
|
|
<li>The DynamicLibrary class can no longer be constructed, its functionality has
|
|
moved to static member functions.</li>
|
|
<li><tt>raw_fd_ostream</tt>'s constructor for opening a given filename now
|
|
takes an extra <tt>Force</tt> argument. If <tt>Force</tt> is set to
|
|
<tt>false</tt>, an error will be reported if a file with the given name
|
|
already exists. If <tt>Force</tt> is set to <tt>true</tt>, the file will
|
|
be silently truncated (which is the behavior before this flag was
|
|
added).</li>
|
|
<li><tt>SCEVHandle</tt> no longer exists, because reference counting is no
|
|
longer done for <tt>SCEV*</tt> objects, instead <tt>const SCEV*</tt> should be
|
|
used.</li>
|
|
|
|
<li>Many APIs, notably <tt>llvm::Value</tt>, now use the <tt>StringRef</tt>
|
|
and <tt>Twine</tt> classes instead of passing <tt>const char*</tt>
|
|
or <tt>std::string</tt>, as described in
|
|
the <a href="ProgrammersManual.html#string_apis">Programmer's Manual</a>. Most
|
|
clients should be unaffected by this transition, unless they are used to <tt>Value::getName()</tt> returning a string. Here are some tips on updating to 2.6:
|
|
<ul>
|
|
<li><tt>getNameStr()</tt> is still available, and matches the old
|
|
behavior. Replacing <tt>getName()</tt> calls with this is an safe option,
|
|
although more efficient alternatives are now possible.</li>
|
|
|
|
<li>If you were just relying on <tt>getName()</tt> being able to be sent to
|
|
a <tt>std::ostream</tt>, consider migrating
|
|
to <tt>llvm::raw_ostream</tt>.</li>
|
|
|
|
<li>If you were using <tt>getName().c_str()</tt> to get a <tt>const
|
|
char*</tt> pointer to the name, you can use <tt>getName().data()</tt>.
|
|
Note that this string (as before), may not be the entire name if the
|
|
name containts embedded null characters.</li>
|
|
|
|
<li>If you were using operator plus on the result of <tt>getName()</tt> and
|
|
treating the result as an <tt>std::string</tt>, you can either
|
|
uses <tt>Twine::str</tt> to get the result as an <tt>std::string</tt>, or
|
|
could move to a <tt>Twine</tt> based design.</li>
|
|
|
|
<li><tt>isName()</tt> should be replaced with comparison
|
|
against <tt>getName()</tt> (this is now efficient).
|
|
</ul>
|
|
</li>
|
|
|
|
<li>The registration interfaces for backend Targets has changed (what was
|
|
previously TargetMachineRegistry). For backend authors, see the <a href="WritingAnLLVMBackend.html#TargetRegistration">Writing An LLVM Backend</a> guide. For clients, the notable API changes are:
|
|
<ul>
|
|
<li><tt>TargetMachineRegistry</tt> has been renamed
|
|
to <tt>TargetRegistry</tt>.</li>
|
|
|
|
<li>Clients should move to using the <tt>TargetRegistry::lookupTarget()</tt>
|
|
function to find targets.</li>
|
|
</ul>
|
|
</li>
|
|
|
|
<li>llvm-dis now fails if output file exists, instead of dumping to stdout.
|
|
FIXME: describe any other tool changes due to the raw_fd_ostream change. FIXME:
|
|
This is not an API change, maybe there should be a tool changes section?</li>
|
|
<li>temporarely due to Context API change passes should call doInitialization()
|
|
method of the pass they inherit from, otherwise Context is NULL.
|
|
FIXME: remove this entry when this is no longer needed.<li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
|
|
|
|
<!-- *********************************************************************** -->
|
|
<div class="doc_section">
|
|
<a name="portability">Portability and Supported Platforms</a>
|
|
</div>
|
|
<!-- *********************************************************************** -->
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>LLVM is known to work on the following platforms:</p>
|
|
|
|
<ul>
|
|
<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
|
|
Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like systems).</li>
|
|
<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit
|
|
and 64-bit modes.</li>
|
|
<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
|
|
<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
|
|
support is available for native builds with Visual C++).</li>
|
|
<li>Sun UltraSPARC workstations running Solaris 10.</li>
|
|
<li>Alpha-based machines running Debian GNU/Linux.</li>
|
|
</ul>
|
|
|
|
<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
|
|
to the machine and operating system on which it is built. However, minor
|
|
porting may be required to get LLVM to work on new platforms. We welcome your
|
|
portability patches and reports of successful builds or error messages.</p>
|
|
|
|
</div>
|
|
|
|
<!-- *********************************************************************** -->
|
|
<div class="doc_section">
|
|
<a name="knownproblems">Known Problems</a>
|
|
</div>
|
|
<!-- *********************************************************************** -->
|
|
|
|
<div class="doc_text">
|
|
|
|
<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>
|
|
|
|
<ul>
|
|
<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
|
|
using the stock GCC 3.x.x series 'out the box',
|
|
See: <a href="#brokengcc">Broken versions of GCC and other tools</a>.
|
|
However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
|
|
for x86/x64 has been made available from the third party AuroraUX Project
|
|
that has been meticulously tested for bootstrapping LLVM & Clang.</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="experimental">Experimental features included with this release</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<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 MSIL, Alpha, SPU, MIPS, and PIC16 backends are experimental.</li>
|
|
<li>The <tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
|
|
supported value for this option.</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="x86-be">Known problems with the X86 back-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<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 backend generates inefficient floating point code when configured
|
|
to generate code for systems that don't have SSE2.</li>
|
|
<li>Win64 code generation wasn't widely tested. Everything should work, but we
|
|
expect small issues to happen. Also, llvm-gcc cannot build the mingw64
|
|
runtime currently due
|
|
to <a href="http://llvm.org/PR2255">several</a>
|
|
<a href="http://llvm.org/PR2257">bugs</a> and due to lack of support for
|
|
the
|
|
'u' inline assembly constraint and for X87 floating point inline assembly.</li>
|
|
<li>The X86-64 backend does not yet support the LLVM IR instruction
|
|
<tt>va_arg</tt>. Currently, the llvm-gcc and front-ends support variadic
|
|
argument constructs on X86-64 by lowering them manually.</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="ppc-be">Known problems with the PowerPC back-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<ul>
|
|
<li>The Linux PPC32/ABI support needs testing for the interpreter and static
|
|
compilation, and lacks support for debug information.</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="arm-be">Known problems with the ARM back-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<ul>
|
|
<li>Support for the Advanced SIMD (Neon) instruction set is still incomplete
|
|
and not well tested. Some features may not work at all, and the code quality
|
|
may be poor in some cases.</li>
|
|
<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>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="sparc-be">Known problems with the SPARC back-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<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>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="mips-be">Known problems with the MIPS back-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<ul>
|
|
<li>The O32 ABI is not fully supported.</li>
|
|
<li>64-bit MIPS targets are not supported yet.</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="alpha-be">Known problems with the Alpha back-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<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>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="c-be">Known problems with the C back-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<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>
|
|
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="c-fe">Known problems with the llvm-gcc C front-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
|
|
Optimization</a> on most platforms "out-of-the-box". Please inquire on the
|
|
LLVMdev mailing list if you are interested.</p>
|
|
|
|
<p>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>If you run into GCC extensions which are not supported, please let us know.
|
|
</p>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>The C++ front-end is considered to be fully
|
|
tested and works for a number of non-trivial programs, including LLVM
|
|
itself, Qt, Mozilla, etc.</p>
|
|
|
|
<ul>
|
|
<li>Exception handling works well on the X86 and PowerPC targets. Currently
|
|
only Linux and Darwin targets are supported (both 32 and 64 bit).</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
<ul>
|
|
<li>Fortran support generally works, but there are still several unresolved bugs
|
|
in Bugzilla. Please see the tools/gfortran component for details.</li>
|
|
</ul>
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
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<a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
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</div>
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|
|
|
<div class="doc_text">
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The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
|
|
technology, and problems should be expected.
|
|
<ul>
|
|
<li>The Ada front-end currently only builds on X86-32. This is mainly due
|
|
to lack of trampoline support (pointers to nested functions) on other platforms.
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|
However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
|
|
which does support trampolines.</li>
|
|
<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
|
|
This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
|
|
exception handling, which is used internally by the compiler.
|
|
Workaround: configure with --disable-bootstrap.</li>
|
|
<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
|
|
and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
|
|
(c380004 also fails with gcc-4.2 mainline).
|
|
If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
|
|
causes the compiler to go into an infinite loop, using up all system memory.</li>
|
|
<li>Some GCC specific Ada tests continue to crash the compiler.</li>
|
|
<li>The -E binder option (exception backtraces)
|
|
<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
|
|
crashing if an exception is raised. Workaround: do not use -E.</li>
|
|
<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
|
|
or finish at a non-byte offset</a> in a record. Workaround: do not pack records
|
|
or use representation clauses that result in a field of a non-discrete type
|
|
starting or finishing in the middle of a byte.</li>
|
|
<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
|
|
'main' as generated by the Ada binder to be invalid</a>.
|
|
Workaround: hand edit the file to use pointers for <tt>argv</tt> and
|
|
<tt>envp</tt> rather than integers.</li>
|
|
<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
|
|
ignored</a>.</li>
|
|
</ul>
|
|
</div>
|
|
|
|
<!-- ======================================================================= -->
|
|
<div class="doc_subsection">
|
|
<a name="ocaml-bindingse">Known problems with the O'Caml bindings</a>
|
|
</div>
|
|
|
|
<div class="doc_text">
|
|
|
|
<p>The Llvm.Linkage module is broken, and has incorrect values. Only
|
|
Llvm.Linkage.External, Llvm.Linkage.Available_externally, and
|
|
Llvm.Linkage.Link_once will be correct. If you need any of the other linkage
|
|
modes, you'll have to write an external C library in order to expose the
|
|
functionality. This has been fixed in the trunk.</p>
|
|
</div>
|
|
|
|
<!-- *********************************************************************** -->
|
|
<div class="doc_section">
|
|
<a name="additionalinfo">Additional Information</a>
|
|
</div>
|
|
<!-- *********************************************************************** -->
|
|
|
|
<div class="doc_text">
|
|
|
|
<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>
|
|
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|
<!-- *********************************************************************** -->
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<a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
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