aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorChris Lattner <sabre@nondot.org>2009-10-13 17:48:04 +0000
committerChris Lattner <sabre@nondot.org>2009-10-13 17:48:04 +0000
commit61358ab84304c641f5a071288d7cfbe3ddd10aa0 (patch)
treefa76caecc7806ccbde7dbf96813b45e554964517
parentf21e69695b0a04aaf3dd8edb7489d7f65bb317e3 (diff)
rename ReleaseNotes-2.6.html -> ReleaseNotes.html
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83990 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat
-rw-r--r--docs/ReleaseNotes-2.6.html1355
-rw-r--r--docs/ReleaseNotes.html1043
2 files changed, 717 insertions, 1681 deletions
diff --git a/docs/ReleaseNotes-2.6.html b/docs/ReleaseNotes-2.6.html
deleted file mode 100644
index 4a1a5f027a..0000000000
--- a/docs/ReleaseNotes-2.6.html
+++ /dev/null
@@ -1,1355 +0,0 @@
-<!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 2.6 Release Notes</title>
-</head>
-<body>
-
-<div class="doc_title">LLVM 2.6 Release Notes</div>
-
-<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 2.6</a></li>
- <li><a href="#whatsnew">What's New in LLVM 2.6?</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>
-
-<!-- *********************************************************************** -->
-<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 2.6. 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://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 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.
--->
-
-
-<!-- Unfinished features in 2.6:
- gcc plugin.
- strong phi elim
- variable debug info for optimized code
- postalloc scheduler: anti dependence breaking, hazard recognizer?
- metadata
- loop dependence analysis
- ELF Writer? How stable?
- <li>PostRA scheduler improvements, ARM adoption (David Goodwin).</li>
- 2.7 supports the GDB 7.0 jit interfaces for debug info.
- 2.7 eliminates ADT/iterator.h
- -->
-
- <!-- for announcement email:
- Logo web page.
- llvm devmtg
- compiler_rt
- KLEE web page at klee.llvm.org
- Many new papers added to /pubs/
- Mention gcc plugin.
-
- -->
-
-<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="subproj">Sub-project Status Update</a>
-</div>
-<!-- *********************************************************************** -->
-
-<div class="doc_text">
-<p>
-The LLVM 2.6 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>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 C family of languages.
-LLVM 2.6 is the first release to officially include Clang, and it provides a
-production quality C and Objective-C compiler. If you are interested in <a
-href="http://clang.llvm.org/performance.html">fast compiles</a> and
-<a href="http://clang.llvm.org/diagnostics.html">good diagnostics</a>, we
-encourage you to try it out. Clang currently compiles typical Objective-C code
-3x faster than GCC and compiles C code about 30% faster than GCC at -O0 -g
-(which is when the most pressure is on the frontend).</p>
-
-<p>In addition to supporting these languages, C++ support is also <a
-href="http://clang.llvm.org/cxx_status.html">well under way</a>, and mainline
-Clang is able to parse the libstdc++ 4.2 headers and even codegen simple apps.
-If you are interested in Clang C++ support or any other Clang feature, we
-strongly encourage you to get involved on the <a
-href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">Clang front-end mailing
-list</a>.</p>
-
-<p>In the LLVM 2.6 time-frame, the Clang team has made many improvements:</p>
-
-<ul>
-<li>C and Objective-C support are now considered production quality.</li>
-<li>AuroraUX, FreeBSD and OpenBSD are now supported.</li>
-<li>Most of Objective-C 2.0 is now supported with the GNU runtime.</li>
-<li>Many many bugs are fixed and lots of features have been added.</li>
-</ul>
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="clangsa">Clang Static Analyzer</a>
-</div>
-
-<div class="doc_text">
-
-<p>Previously announced in the 2.4 and 2.5 LLVM releases, the Clang project also
-includes an early stage static source code analysis tool for <a
-href="http://clang.llvm.org/StaticAnalysis.html">automatically finding bugs</a>
-in C and Objective-C programs. The tool performs checks to find
-bugs that occur on a specific path within a program.</p>
-
-<p>In the LLVM 2.6 time-frame, the analyzer core has undergone several important
-improvements and cleanups and now includes a new <em>Checker</em> interface that
-is intended to eventually serve as a basis for domain-specific checks. Further,
-in addition to generating HTML files for reporting analysis results, the
-analyzer can now also emit bug reports in a structured XML format that is
-intended to be easily readable by other programs.</p>
-
-<p>The set of checks performed by the static analyzer continues to expand, and
-future plans for the tool include full source-level inter-procedural analysis
-and deeper checks such as buffer overrun detection. There are many opportunities
-to extend and enhance the static analyzer, and anyone interested in working on
-this project is encouraged to get involved!</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>
-VMKit version 0.26 builds with LLVM 2.6 and you can find it on its
-<a href="http://vmkit.llvm.org/releases/">web page</a>. The release includes
-bug fixes, cleanup and new features. The major changes are:</p>
-
-<ul>
-
-<li>A new llcj tool to generate shared libraries or executables of Java
- files.</li>
-<li>Cooperative garbage collection. </li>
-<li>Fast subtype checking (paper from Click et al [JGI'02]). </li>
-<li>Implementation of a two-word header for Java objects instead of the original
- three-word header. </li>
-<li>Better Java specification-compliance: division by zero checks, stack
- overflow checks, finalization and references support. </li>
-
-</ul>
-</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.</p>
-
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="klee">KLEE: Symbolic Execution and Automatic Test Case Generator</a>
-</div>
-
-<div class="doc_text">
-<p>
-The new LLVM <a href="http://klee.llvm.org/">KLEE project</a> is a symbolic
-execution framework for programs in LLVM bitcode form. KLEE tries to
-symbolically evaluate "all" paths through the application and records state
-transitions that lead to fault states. This allows it to construct testcases
-that lead to faults and can even be used to verify algorithms. For more
-details, please see the <a
-href="http://llvm.org/pubs/2008-12-OSDI-KLEE.html">OSDI 2008 paper</a> about
-KLEE.</p>
-
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="dragonegg">DragonEgg: GCC-4.5 as an LLVM frontend</a>
-</div>
-
-<div class="doc_text">
-<p>
-The goal of <a href="http://dragonegg.llvm.org/">DragonEgg</a> is to make
-gcc-4.5 act like llvm-gcc without requiring any gcc modifications whatsoever.
-<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a shared library (llvm.so)
-that is loaded by gcc at runtime. It uses the new gcc plugin architecture to
-disable the GCC optimizers and code generators, and schedule the LLVM optimizers
-and code generators (or direct output of LLVM IR) instead. Currently only Linux
-and Darwin are supported, and only on x86-32 and x86-64. It should be easy to
-add additional unix-like architectures and other processor families. In theory
-it should be possible to use <a href="http://dragonegg.llvm.org/">DragonEgg</a>
-with any language supported by gcc, however only C and Fortran work well for the
-moment. Ada and C++ work to some extent, while Java, Obj-C and Obj-C++ are so
-far entirely untested. Since gcc-4.5 has not yet been released, neither has
-<a href="http://dragonegg.llvm.org/">DragonEgg</a>. To build
-<a href="http://dragonegg.llvm.org/">DragonEgg</a> you will need to check out the
-development versions of <a href="http://gcc.gnu.org/svn.html/"> gcc</a>,
-<a href="http://llvm.org/docs/GettingStarted.html#checkout">llvm</a> and
-<a href="http://dragonegg.llvm.org/">DragonEgg</a> from their respective
-subversion repositories, and follow the instructions in the
-<a href="http://dragonegg.llvm.org/">DragonEgg</a> README.
-</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 (MC) Toolkit project is a (very early) effort to build
-better tools for dealing with machine code, object file formats, etc. The idea
-is to be able to generate most of the target specific details of assemblers and
-disassemblers from existing LLVM target .td files (with suitable enhancements),
-and to build infrastructure for reading and writing common object file formats.
-One of the first deliverables is to build a full assembler and integrate it into
-the compiler, which is predicted to substantially reduce compile time in some
-scenarios.
-</p>
-
-<p>In the LLVM 2.6 timeframe, the MC framework has grown to the point where it
-can reliably parse and pretty print (with some encoding information) a
-darwin/x86 .s file successfully, and has the very early phases of a Mach-O
-assembler in progress. Beyond the MC framework itself, major refactoring of the
-LLVM code generator has started. The idea is to make the code generator reason
-about the code it is producing in a much more semantic way, rather than a
-textual way. For example, the code generator now uses MCSection objects to
-represent section assignments, instead of text strings that print to .section
-directives.</p>
-
-<p>MC is an early and ongoing project that will hopefully continue to lead to
-many improvements in the code generator and build infrastructure useful for many
-other situations.
-</p>
-
-</div>
-
-
-<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="externalproj">External Open Source Projects Using LLVM 2.6</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 2.6.</p>
-</div>
-
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="Rubinius">Rubinius</a>
-</div>
-
-<div class="doc_text">
-<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 core class
-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 uncommon traps are all used to
-remove dynamism from ruby execution and increase performance.</p>
-
-<p>Since LLVM 2.5, Rubinius has made several major leaps forward, implementing
-a counter based JIT, type feedback and speculative method inlining.
-</p>
-
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="macruby">MacRuby</a>
-</div>
-
-<div class="doc_text">
-
-<p>
-<a href="http://macruby.org">MacRuby</a> is an implementation of Ruby on top of
-core Mac OS X technologies, such as the Objective-C common runtime and garbage
-collector and the CoreFoundation framework. It is principally developed by
-Apple and aims at enabling the creation of full-fledged Mac OS X applications.
-</p>
-
-<p>
-MacRuby uses LLVM for optimization passes, JIT and AOT compilation of Ruby
-expressions. It also uses zero-cost DWARF exceptions to implement Ruby exception
-handling.</p>
-
-</div>
-
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="pure">Pure</a>
-</div>
-
-<div class="doc_text">
-<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. 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 C interface. The interpreter uses LLVM as a backend to
- JIT-compile Pure programs to fast native code.</p>
-
-<p>Pure versions 0.31 and later have been tested and are known to work with
-LLVM 2.6 (and continue to work with older LLVM releases >= 2.3 as well).
-</p>
-</div>
-
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="ldc">LLVM D Compiler</a>
-</div>
-
-<div class="doc_text">
-<p>
-<a href="http://www.dsource.org/projects/ldc">LDC</a> is an implementation of
-the D Programming Language using the LLVM optimizer and code generator.
-The LDC project works great with the LLVM 2.6 release. General improvements in
-this
-cycle have included new inline asm constraint handling, better debug info
-support, general bug fixes and better x86-64 support. This has allowed
-some major improvements in LDC, getting it much closer to being as
-fully featured as the original DMD compiler from DigitalMars.
-</p>
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="RoadsendPHP">Roadsend PHP</a>
-</div>
-
-<div class="doc_text">
-<p>
-<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
-source implementation of the PHP programming
-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>
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="UnladenSwallow">Unladen Swallow</a>
-</div>
-
-<div class="doc_text">
-<p>
-<a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
-branch of <a href="http://python.org/">Python</a> intended to be fully
-compatible and significantly faster. It uses LLVM's optimization passes and JIT
-compiler.</p>
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="llvm-lua">llvm-lua</a>
-</div>
-
-<div class="doc_text">
-<p>
-<a href="http://code.google.com/p/llvm-lua/">LLVM-Lua</a> uses LLVM to add JIT
-and static compiling support to the Lua VM. Lua bytecode is analyzed to
-remove type checks, then LLVM is used to compile the bytecode down to machine
-code.</p>
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="icedtea">IcedTea Java Virtual Machine Implementation</a>
-</div>
-
-<div class="doc_text">
-<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>
-</div>
-
-
-
-<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="whatsnew">What's New in LLVM 2.6?</a>
-</div>
-<!-- *********************************************************************** -->
-
-<div class="doc_text">
-
-<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>
-
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="majorfeatures">Major New Features</a>
-</div>
-
-<div class="doc_text">
-
-<p>LLVM 2.6 includes several major new capabilities:</p>
-
-<ul>
-<li>New <a href="#compiler-rt">compiler-rt</a>, <A href="#klee">KLEE</a>
- and <a href="#mc">machine code toolkit</a> sub-projects.</li>
-<li>Debug information now includes line numbers when optimizations are enabled.
- This allows statistical sampling tools like OProfile and Shark to map
- samples back to source lines.</li>
-<li>LLVM now includes new experimental backends to support the MSP430, SystemZ
- and BlackFin architectures.</li>
-<li>LLVM supports a new <a href="GoldPlugin.html">Gold Linker Plugin</a> which
- enables support for <a href="LinkTimeOptimization.html">transparent
- link-time optimization</a> on ELF targets when used with the Gold binutils
- linker.</li>
-<li>LLVM now supports doing optimization and code generation on multiple
- threads. Please see the <a href="ProgrammersManual.html#threading">LLVM
- Programmer's Manual</a> for more information.</li>
-<li>LLVM now has experimental support for <a
- href="http://nondot.org/~sabre/LLVMNotes/EmbeddedMetadata.txt">embedded
- metadata</a> in LLVM IR, though the implementation is not guaranteed to be
- final and the .bc file format may change in future releases. Debug info
- does not yet use this format in LLVM 2.6.</li>
-</ul>
-
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="coreimprovements">LLVM IR and Core Improvements</a>
-</div>
-
-<div class="doc_text">
-<p>LLVM IR has several new features for better support of new targets and that
-expose new optimization opportunities:</p>
-
-<ul>
-<li>The <a href="LangRef.html#i_add">add</a>, <a
- href="LangRef.html#i_sub">sub</a> and <a href="LangRef.html#i_mul">mul</a>
- instructions have been split into integer and floating point versions (like
- divide and remainder), introducing new <a
- href="LangRef.html#i_fadd">fadd</a>, <a href="LangRef.html#i_fsub">fsub</a>,
- and <a href="LangRef.html#i_fmul">fmul</a> instructions.</li>
-<li>The <a href="LangRef.html#i_add">add</a>, <a
- href="LangRef.html#i_sub">sub</a> and <a href="LangRef.html#i_mul">mul</a>
- instructions now support optional "nsw" and "nuw" bits which indicate that
- the operation is guaranteed to not overflow (in the signed or
- unsigned case, respectively). This gives the optimizer more information and
- can be used for things like C signed integer values, which are undefined on
- overflow.</li>
-<li>The <a href="LangRef.html#i_sdiv">sdiv</a> instruction now supports an
- optional "exact" flag which indicates that the result of the division is
- guaranteed to have a remainder of zero. This is useful for optimizing pointer
- subtraction in C.</li>
-<li>The <a href="LangRef.html#i_getelementptr">getelementptr</a> instruction now
- supports arbitrary integer index values for array/pointer indices. This
- allows for better code generation on 16-bit pointer targets like PIC16.</li>
-<li>The <a href="LangRef.html#i_getelementptr">getelementptr</a> instruction now
- supports an "inbounds" optimization hint that tells the optimizer that the
- pointer is guaranteed to be within its allocated object.</li>
-<li>LLVM now support a series of new linkage types for global values which allow
- for better optimization and new capabilities:
- <ul>
- <li><a href="LangRef.html#linkage_linkonce">linkonce_odr</a> and
- <a href="LangRef.html#linkage_weak">weak_odr</a> have the same linkage
- semantics as the non-"odr" linkage types. The difference is that these
- linkage types indicate that all definitions of the specified function
- are guaranteed to have the same semantics. This allows inlining
- templates functions in C++ but not inlining weak functions in C,
- which previously both got the same linkage type.</li>
- <li><a href="LangRef.html#linkage_available_externally">available_externally
- </a> is a new linkage type that gives the optimizer visibility into the
- definition of a function (allowing inlining and side effect analysis)
- but that does not cause code to be generated. This allows better
- optimization of "GNU inline" functions, extern templates, etc.</li>
- <li><a href="LangRef.html#linkage_linker_private">linker_private</a> is a
- new linkage type (which is only useful on Mac OS X) that is used for
- some metadata generation and other obscure things.</li>
- </ul></li>
-<li>Finally, target-specific intrinsics can now return multiple values, which
- is useful for modeling target operations with multiple results.</li>
-</ul>
-
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="optimizer">Optimizer Improvements</a>
-</div>
-
-<div class="doc_text">
-
-<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>The <a href="Passes.html#scalarrepl">Scalar Replacement of Aggregates</a>
- pass has many improvements that allow it to better promote vector unions,
- variables which are memset, and much more strange code that can happen to
- do bitfield accesses to register operations. An interesting change is that
- it now produces "unusual" integer sizes (like i1704) in some cases and lets
- other optimizers clean things up.</li>
-<li>The <a href="Passes.html#loop-reduce">Loop Strength Reduction</a> pass now
- promotes small integer induction variables to 64-bit on 64-bit targets,
- which provides a major performance boost for much numerical code. It also
- promotes shorts to int on 32-bit hosts, etc. LSR now also analyzes pointer
- expressions (e.g. getelementptrs), as well as integers.</li>
-<li>The <a href="Passes.html#gvn">GVN</a> pass now eliminates partial
- redundancies of loads in simple cases.</li>
-<li>The <a href="Passes.html#inline">Inliner</a> now reuses stack space when
- inlining similar arrays from multiple callees into one caller.</li>
-<li>LLVM includes a new experimental Static Single Information (SSI)
- construction pass.</li>
-
-</ul>
-
-</div>
-
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="executionengine">Interpreter and JIT Improvements</a>
-</div>
-
-<div class="doc_text">
-
-<ul>
-<li>LLVM has a new "EngineBuilder" class which makes it more obvious how to
- set up and configure an ExecutionEngine (a JIT or interpreter).</li>
-<li>The JIT now supports generating more than 16M of code.</li>
-<li>When configured with <tt>--with-oprofile</tt>, the JIT can now inform
- OProfile about JIT'd code, allowing OProfile to get line number and function
- name information for JIT'd functions.</li>
-<li>When "libffi" is available, the LLVM interpreter now uses it, which supports
- calling almost arbitrary external (natively compiled) functions.</li>
-<li>Clients of the JIT can now register a 'JITEventListener' object to receive
- callbacks when the JIT emits or frees machine code. The OProfile support
- uses this mechanism.</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
-it run faster:</p>
-
-<ul>
-
-<li>The <tt>llc -asm-verbose</tt> option (exposed from llvm-gcc as <tt>-dA</tt>
- and clang as <tt>-fverbose-asm</tt> or <tt>-dA</tt>) now adds a lot of
- useful information in comments to
- the generated .s file. This information includes location information (if
- built with <tt>-g</tt>) and loop nest information.</li>
-<li>The code generator now supports a new MachineVerifier pass which is useful
- for finding bugs in targets and codegen passes.</li>
-<li>The Machine LICM is now enabled by default. It hoists instructions out of
- loops (such as constant pool loads, loads from read-only stubs, vector
- constant synthesization code, etc.) and is currently configured to only do
- so when the hoisted operation can be rematerialized.</li>
-<li>The Machine Sinking pass is now enabled by default. This pass moves
- side-effect free operations down the CFG so that they are executed on fewer
- paths through a function.</li>
-<li>The code generator now performs "stack slot coloring" of register spills,
- which allows spill slots to be reused. This leads to smaller stack frames
- in cases where there are lots of register spills.</li>
-<li>The register allocator has many improvements to take better advantage of
- commutable operations, various spiller peephole optimizations, and can now
- coalesce cross-register-class copies.</li>
-<li>Tblgen now supports multiclass inheritance and a number of new string and
- list operations like <tt>!(subst)</tt>, <tt>!(foreach)</tt>, <tt>!car</tt>,
- <tt>!cdr</tt>, <tt>!null</tt>, <tt>!if</tt>, <tt>!cast</tt>.
- These make the .td files more expressive and allow more aggressive factoring
- of duplication across instruction patterns.</li>
-<li>Target-specific intrinsics can now be added without having to hack VMCore to
- add them. This makes it easier to maintain out-of-tree targets.</li>
-<li>The instruction selector is better at propagating information about values
- (such as whether they are sign/zero extended etc.) across basic block
- boundaries.</li>
-<li>The SelectionDAG datastructure has new nodes for representing buildvector
- and <a href="http://llvm.org/PR2957">vector shuffle</a> operations. This
- makes operations and pattern matching more efficient and easier to get
- right.</li>
-<li>The Prolog/Epilog Insertion Pass now has experimental support for performing
- the "shrink wrapping" optimization, which moves spills and reloads around in
- the CFG to avoid doing saves on paths that don't need them.</li>
-<li>LLVM includes new experimental support for writing ELF .o files directly
- from the compiler. It works well for many simple C testcases, but doesn't
- support exception handling, debug info, inline assembly, etc.</li>
-<li>Targets can now specify register allocation hints through
- <tt>MachineRegisterInfo::setRegAllocationHint</tt>. A regalloc hint consists
- of hint type and physical register number. A hint type of zero specifies a
- register allocation preference. Other hint type values are target specific
- which are resolved by <tt>TargetRegisterInfo::ResolveRegAllocHint</tt>. An
- example is the ARM target which uses register hints to request that the
- register allocator provide an even / odd register pair to two virtual
- registers.</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>
-
-<li>SSE 4.2 builtins are now supported.</li>
-<li>GCC-compatible soft float modes are now supported, which are typically used
- by OS kernels.</li>
-<li>X86-64 now models implicit zero extensions better, which allows the code
- generator to remove a lot of redundant zexts. It also models the 8-bit "H"
- registers as subregs, which allows them to be used in some tricky
- situations.</li>
-<li>X86-64 now supports the "local exec" and "initial exec" thread local storage
- model.</li>
-<li>The vector forms of the <a href="LangRef.html#i_icmp">icmp</a> and <a
- href="LangRef.html#i_fcmp">fcmp</a> instructions now select to efficient
- SSE operations.</li>
-<li>Support for the win64 calling conventions have improved. The primary
- missing feature is support for varargs function definitions. It seems to
- work well for many win64 JIT purposes.</li>
-<li>The X86 backend has preliminary support for <a
- href="CodeGenerator.html#x86_memory">mapping address spaces to segment
- register references</a>. This allows you to write GS or FS relative memory
- accesses directly in LLVM IR for cases where you know exactly what you're
- doing (such as in an OS kernel). There are some known problems with this
- support, but it works in simple cases.</li>
-<li>The X86 code generator has been refactored to move all global variable
- reference logic to one place
- (<tt>X86Subtarget::ClassifyGlobalReference</tt>) which
- makes it easier to reason about.</li>
-
-</ul>
-
-</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>
-<li>Support for floating-point, indirect function calls, and
- passing/returning aggregate types to functions.
-<li>The code generator is able to generate debug info into output COFF files.
-<li>Support for placing an object into a specific section or at a specific
- address in memory.</li>
-</ul>
-
-<p>Things not yet supported:</p>
-
-<ul>
-<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.</li>
-
-<li>The AAPCS-VFP "hard float" calling conventions are also supported with the
-<tt>-float-abi=hard</tt> flag.</li>
-
-<li>The ARM calling convention code is now tblgen generated instead of resorting
- to C++ code.</li>
-</ul>
-
-<p>These features are still somewhat experimental
-and subject to change. The Neon intrinsics, in particular, may change in future
-releases of LLVM. ARMv7 support has progressed a lot on top of tree since 2.6
-branched.</p>
-
-
-</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>Mips now supports O32 Calling Convention.</li>
-<li>Many improvements to the 32-bit PowerPC SVR4 ABI (used on powerpc-linux)
- support, lots of bugs fixed.</li>
-<li>Added support for the 64-bit PowerPC SVR4 ABI (used on powerpc64-linux).
- Needs more testing.</li>
-</ul>
-
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="newapis">New Useful APIs</a>
-</div>
-
-<div class="doc_text">
-
-<p>This release includes a number of new APIs that are used internally, which
- may also be useful for external clients.
-</p>
-
-<ul>
-<li>New <a href="http://llvm.org/doxygen/PrettyStackTrace_8h-source.html">
- <tt>PrettyStackTrace</tt> class</a> allows crashes of llvm tools (and applications
- that integrate them) to provide more detailed indication of what the
- compiler was doing at the time of the crash (e.g. running a pass).
- At the top level for each LLVM tool, it includes the command line argument