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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link rel="stylesheet" href="llvm.css" type="text/css">
<title>LLVM 2.4 Release Notes</title>
</head>
<body>
<div class="doc_title">LLVM 2.4 Release Notes</div>
<ol>
<li><a href="#intro">Introduction</a></li>
<li><a href="#changes">Major Changes and Sub-project Status</a></li>
<li><a href="#whatsnew">What's New?</a></li>
<li><a href="GettingStarted.html">Installation Instructions</a></li>
<li><a href="#portability">Portability and Supported Platforms</a></li>
<li><a href="#knownproblems">Known Problems</a>
<li><a href="#additionalinfo">Additional Information</a></li>
</ol>
<div class="doc_author">
<p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
</div>
<!-- Done through Week-of-Mon-20080324.txt -->
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="intro">Introduction</a>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<p>This document contains the release notes for the LLVM compiler
infrastructure, release 2.4. Here we describe the status of LLVM, including
major improvements from the previous release and any known problems. All LLVM
releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
releases web site</a>.</p>
<p>For more information about LLVM, including information about the latest
release, please check out the <a href="http://llvm.org/">main LLVM
web site</a>. If you have questions or comments, the <a
href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
list</a> is a good place to send them.</p>
<p>Note that if you are reading this file from a Subversion checkout or the
main LLVM web page, this document applies to the <i>next</i> release, not the
current one. To see the release notes for a specific releases, please see the
<a href="http://llvm.org/releases/">releases page</a>.</p>
</div>
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="changes">Major Changes and Sub-project Status</a>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<p>This is the fifteenth public release of the LLVM Compiler Infrastructure.
It includes a large number of features and refinements from LLVM 2.3.</p>
</div>
<!-- Unfinished features in 2.4:
Machine LICM
Machine Sinking
LegalizeDAGTypes
-->
<!--=========================================================================-->
<div class="doc_subsection">
<a name="changes">Major Changes in LLVM 2.4</a>
</div>
<div class="doc_text">
<p>....</p>
<p>LLVM API Changes:</p>
<ul>
<li>....</li>
<li>... Attributes changes ... </li>
<li>The <tt>DbgStopPointInst</tt> methods <tt>getDirectory</tt> and
<tt>getFileName</tt> now return <tt>Value*</tt> instead of strings. These can be
converted to strings using <tt>llvm::GetConstantStringInfo</tt> defined via
"llvm/Analysis/ValueTracking.h".</li>
<li>API change: BinaryOperator::create -> Create (CmpInst, CastInst too)</li>
</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="otherprojects">Other LLVM Sub-Projects</a>
</div>
<div class="doc_text">
<p>
The core LLVM 2.4 distribution currently consists of code from the core LLVM
repository (which roughly contains the LLVM optimizer, code generators and
supporting tools) and the llvm-gcc repository. In addition to this code, the
LLVM Project includes other sub-projects that are in development. The two which
are the most actively developed are the <a href="#clang">Clang Project</a> and
<a href="#vmkit">vmkit Project</a>.
</p>
</div>
<!--=========================================================================-->
<div class="doc_subsubsection">
<a name="vmkit">vmkit</a>
</div>
<div class="doc_text">
<p>
The <a href="http://vmkit.llvm.org/">"vmkit" project</a> is an implementation of
a JVM and a CLI Virtual Machines (Microsoft .NET is an
implementation of the CLI) using the Just-In-Time compiler of LLVM.</p>
<p>...</p>
</div>
<!--=========================================================================-->
<div class="doc_subsubsection">
<a name="clang">Clang</a>
</div>
<div class="doc_text">
<p>The <a href="http://clang.llvm.org/">Clang project</a> is an effort to build
a set of new 'LLVM native' front-end technologies for the LLVM optimizer
and code generator. Clang is continuing to make major strides forward in all
areas. Its C and Objective-C parsing support is very solid, and the code
generation support is far enough along to build many C applications. While not
yet production quality, it is progressing very nicely. In addition, C++
front-end work has started to make significant progress.</p>
<p>Codegen progress/state
</p>
<p>
<a href="http://clang.llvm.org/StaticAnalysis.html">static analysis tool</a>
</p>
</div>
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="whatsnew">What's New?</a>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<p>LLVM 2.4 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>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="majorfeatures">Major New Features</a>
</div>
<div class="doc_text">
<p>LLVM 2.4 includes several major new capabilities:</p>
<ul>
<li>
<p>MRVs got generalized to FCAs. getresult is gone, ret with multiple values
is gone.</p>
</li>
<li><p>fast isel, -O0 compile times</p></li>
<li><p>Attrs changes?</p></li>
<li><p>Initial PIC16 port</p></li>
<li><p> builtin sync_compare_and_swap builtins + intrinsics</p></li>
<li><p>...</p></li>
</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
</div>
<div class="doc_text">
<p>LLVM 2.4 fully supports the llvm-gcc 4.2 front-end, and includes support
for the C, C++, Objective-C, Ada, and Fortran front-ends.</p>
<p>
<ul>
<li>...</li>
</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="coreimprovements">LLVM Core Improvements</a>
</div>
<div class="doc_text">
<p>New features include:
</p>
<ul>
<li>use diet patch landed: saved 15% IR memory footprint</li>
<li>LLVM IR now directly represents "common" linkage, instead of
representing it as a form of weak linkage.</li>
<li>...</li>
</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="optimizer">Optimizer Improvements</a>
</div>
<div class="doc_text">
<p>In addition to a huge array of bug fixes and minor performance tweaks, the
LLVM 2.4 optimizers support a few major enhancements:</p>
<ul>
<li>Old-ADCE used control dependence and deleted output-free infinite loops.
Added a new Loop deletion pass (for deleting output free provably-finite loops)
and rewrote ADCE to be simpler faster, and not need control dependence.</li>
<li>SparsePropagation framework for lattice-based dataflow solvers.</li>
<li>LoadVN and GCSE finally bit the dust?</li>
<li>Tail duplication was is removed from the standard optimizer sequence.</li>
</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="codegen">Code Generator Improvements</a>
</div>
<div class="doc_text">
<p>We 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>Selection dag speedups</li>
<li>...</li>
</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="x86specific">X86/X86-64 Specific Improvements</a>
</div>
<div class="doc_text">
<p>New target-specific features include:
</p>
<ul>
<li>Exception handling is supported by default on x86-64 linux platform.</li>
<li>...</li>
</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="targetspecific">Other Targ
|
