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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 2.8 Release Notes</title>
</head>
<body>
<div class="doc_title">LLVM 2.8 Release Notes</div>
<img align=right src="http://llvm.org/img/DragonSmall.png"
width="136" height="136" alt="LLVM Dragon Logo">
<ol>
<li><a href="#intro">Introduction</a></li>
<li><a href="#subproj">Sub-project Status Update</a></li>
<li><a href="#externalproj">External Projects Using LLVM 2.8</a></li>
<li><a href="#whatsnew">What's New in LLVM 2.8?</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>
<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>
<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.8
release.<br>
You may prefer the
<a href="http://llvm.org/releases/2.7/docs/ReleaseNotes.html">LLVM 2.7
Release Notes</a>.</h1>
<!-- *********************************************************************** -->
<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 2.8. Here we describe the status of LLVM, including
major improvements from the previous release and significant 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://lists.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 release, please see the
<a href="http://llvm.org/releases/">releases page</a>.</p>
</div>
<!--
Almost dead code.
include/llvm/Analysis/LiveValues.h => Dan
lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8.
llvm/Analysis/PointerTracking.h => Edwin wants this, consider for 2.8.
GEPSplitterPass
-->
<!-- Features that need text if they're finished for 2.8:
combiner-aa?
strong phi elim
llvm.dbg.value: variable debug info for optimized code
loop dependence analysis
TBAA
-->
<!-- for announcement email:
Logo web page.
Many new papers added to /pubs/
-->
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="subproj">Sub-project Status Update</a>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<p>
The LLVM 2.8 distribution currently consists of code from the core LLVM
repository (which roughly includes the LLVM optimizers, code generators
and supporting tools), the Clang repository and the llvm-gcc repository. In
addition to this code, the LLVM Project includes other sub-projects that are in
development. Here we include updates on these subprojects.
</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
</div>
<div class="doc_text">
<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
C++, and Objective-C languages. Clang aims to provide a better user experience
through expressive diagnostics, a high level of conformance to language
standards, fast compilation, and low memory use. Like LLVM, Clang provides a
modular, library-based architecture that makes it suitable for creating or
integrating with other development tools. Clang is considered a
production-quality compiler for C and Objective-C on x86 (32- and 64-bit).</p>
<p>In the LLVM 2.8 time-frame, the Clang team has made many improvements:</p>
<ul>
</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="clangsa">Clang Static Analyzer</a>
</div>
<div class="doc_text">
<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a>
project is an effort to use static source code analysis techniques to
automatically find bugs in C and Objective-C programs (and hopefully <a
href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the
future</a>!). The tool is very good at finding bugs that occur on specific
paths through code, such as on error conditions.</p>
<p>In the LLVM 2.8 time-frame,
</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</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 Machine (Microsoft .NET is an
implementation of the CLI) using LLVM for static and just-in-time
compilation.</p>
<p>With the release of LLVM 2.8, ...</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
</div>
<div class="doc_text">
<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"
function. The compiler-rt library provides highly optimized implementations of
this and other low-level routines (some are 3x faster than the equivalent
libgcc routines).</p>
<p>
All of the code in the compiler-rt project is available under the standard LLVM
License, a "BSD-style" license. New in LLVM 2.8:
Soft float support
</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
</div>
<div class="doc_text">
<p>
<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
gcc-4.5. Unlike llvm-gcc, which makes many intrusive changes to the underlying
gcc-4.2 code, dragonegg in theory does not require any gcc-4.5 modifications
whatsoever (currently one small patch is needed). This is thanks to the new
<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>, which
makes it possible to modify the behaviour of gcc at runtime by loading a plugin,
which is nothing more than a dynamic library which conforms to the gcc plugin
interface. DragonEgg is a gcc plugin that causes the LLVM optimizers to be run
instead of the gcc optimizers, and the LLVM code generators instead of the gcc
code generators, just like llvm-gcc. To use it, you add
"-fplugin=path/dragonegg.so" to the gcc-4.5 command line, and gcc-4.5 magically
becomes llvm-gcc-4.5!
</p>
<p>
DragonEgg is still a work in progress. Currently C works very well, while C++,
Ada and Fortran work fairly well. All other languages either don't work at all,
or only work poorly. For the moment only the x86-32 and x86-64 targets are
supported, and only on linux and darwin (darwin needs an additional gcc patch).
</p>
<p>
2.8 status here.
</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
<a name="mc">llvm-mc: Machine Code Toolkit</a>
</div>
<div class="doc_text">
<p>
The LLVM Machine Code (aka MC) sub-project of LLVM 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. It is a sub-project of LLVM which provides it with a number of advantages
over other compilers that do not have tightly integrated assembly-level tools.
For a gentle introduction, 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>
<p>2.8 status here</p>
</div>
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="externalproj">External Open Source Projects Using LLVM 2.8</a>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<p>An exciting aspect of LLVM is that it is used as an enabling technology for
a lot of other language and tools projects. This section lists some of the
projects that have already been updated to work with LLVM 2.8.</p>
</div
|
