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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 2.3 Release Notes</title>
</head>
<body>
<div class="doc_title">LLVM 2.3 Release Notes</div>
<ol>
<li><a href="#intro">Introduction</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>
<!-- *********************************************************************** -->
<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 2.3. 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="whatsnew">What's New?</a>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<p>This is the fourteenth public release of the LLVM Compiler Infrastructure.
It includes a large number of features and refinements from LLVM 2.2.</p>
</div>
<!-- Unfinished features in 2.3:
Index Set Splitting not enabled by default
Machine LICM
Machine Sinking
LegalizeDAGTypes
-->
<!--=========================================================================-->
<div class="doc_subsection">
<a name="deprecation">Removed features in LLVM 2.3</a>
</div>
<div class="doc_text">
<p>LLVM 2.2 was the last LLVM release to support llvm-gcc 4.0 and llvm-upgrade.
llvm-gcc 4.0 has been replaced with llvm-gcc 4.2. llvm-upgrade was useful for
upgrading LLVM 1.9 files to LLVM 2.x syntax, but you can always use a previous
LLVM release to do this. One nice impact of this is that the LLVM regressionn
test suite no longer depends on llvm-upgrade, which makes it run faster.</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="majorfeatures">Major New Features</a>
</div>
<div class="doc_text">
<p>LLVM 2.3 includes several major new capabilities:</p>
<ul>
<li>Multiple Return Value Support</li>
<li><p>LLVM 2.3 includes a complete reimplementation of the "llvmc" tool. It is
designed to overcome several problems of the original llvmc and to provide a
superset of the features as the 'gcc' driver.</p>
<p>The main features of llvmc2 is:</p>
<ul>
<li>Extended handling of command line options and smart rules for
dispatching them to different tools.</li>
<li>Flexible (and extensible) rules for defining different tools.</li>
<li>The different intermediate steps performed by tools are represented
as edged in the abstract graph.</li>
</l>The 'language' for driver behaviour definition is tablegen and thus
it's relatively easy to add new features.</li>
<li>The definition of driver is transformed into set of C++ classes, thus
no runtime interpretation is needed.</li>
</ul>
</li>
</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="frontends">llvm-gcc 4.2 Improvements and Clang</a>
</div>
<div class="doc_text">
<p>LLVM 2.3 fully supports llvm-gcc 4.2 front-end.</p>
<p>llvm-gcc 4.2 includes numerous fixes to better support the Objective-C
front-end. Objective-C now works very well on Mac OS/X.</p>
<p>llvm-gcc 4.2 includes many other fixes which improve conformance with the
relevant parts of the GCC testsuite.</p>
<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. Currently, its C and Objective-C support is maturing
nicely, and it has advanced source-to-source analysis and transformation
capabilities. If you are interested in building source-level tools for C and
Objective-C (and eventually C++), you should take a look. However, note that
clang is not an official part of the LLVM 2.3 release. If you are interested in
this project, please see its <a href="http://clang.llvm.org/">web site</a>.</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="coreimprovements">LLVM Core Improvements</a>
</div>
<div class="doc_text">
<p>New features include:
</p>
Common linkage?
Atomic operation support, Alpha, X86, PowerPC. "__sync_syncronize"
<ul>
</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>MemOperand in the code generator: describe me!.</li>
<li>i128 support and APInt through most of codegen.</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 2.3 optimizers support a few major enhancements:</p>
<ul>
<li>Loop index set splitting on by default: describe me.</li>
<li>LLVM includes a new memcpy optimization pass which optimizes out dead
memcpy calls and unneeded copies of aggregates.</li>
</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="targetspecific">Target Specific Improvements</a>
</div>
<div class="doc_text">
<p>New target-specific features include:
</p>
<ul>
<li>llvm-gcc's X86-64 ABI conformance is far improved, particularly in the
area of passing and returning structures by value. llvm-gcc Compiled code
now interoperates very well on X86-64 systems with other compilers.</li>
<li>The LLVM X86 backend now supports the support SSE 4.1 instruction set, and
the llvm-gcc 4.2 front-end supports the SSE 4.1 compiler builtins.</li>
<li>The X86 backend now does a number of optimizations that aim to avoid
converting numbers back and forth from SSE registers to the X87 floating
point stack.</li>
<li>The X86 backend supports stack realignment, which is particularly useful for
vector code on OS's without 16-byte aligned stacks.</li>
<li>The X86 backend now supports the "sseregparm" options in GCC, which allow
functions to be tagged as passing floating point values in SSE
registers.</li>
<li>Trampolines (taking the address of a nested function) now work on
Linux/x86-64.</li>
</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="otherimprovements">Other Improvements</a>
</div>
<div class="doc_text">
<p>New features include:
</p>
<ul>
<li>LLVM now builds with GCC 4.3.</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 running Red Hat Linux, Fedora Core and FreeBSD
(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 8.</li>
<li>Alpha-based machines running Debian GNU/Linux.</li>
<li>Itanium-based machines running Linux and HP-UX.</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 all known problems with the LLVM system, listed by
component. As new problems are discovered, they will be added to these
sections. 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>
</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, IA64, Alpha, SPU, and MIPS backends are experimental.</li>
<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
value for this option.</li>
</ul>
</div>
<!-- ======================================================================= -->
<div class="doc_subsection"
|
