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authorBill Wendling <isanbard@gmail.com>2010-10-04 19:55:17 +0000
committerBill Wendling <isanbard@gmail.com>2010-10-04 19:55:17 +0000
commit43ab46e2aa101ded49faa552e8e3f6fce8aecd1c (patch)
tree7186eaaf9ce78a64f4e62342846e547e7874a8c7
parent7bcc388e1dd54a018cfee54215b970ee416d2254 (diff)
Update release notes for 2.8 release.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_28@115548 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat
-rw-r--r--docs/ReleaseNotes.html982
1 files changed, 706 insertions, 276 deletions
diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html
index e6249a6d0b..a8c20054c6 100644
--- a/docs/ReleaseNotes.html
+++ b/docs/ReleaseNotes.html
@@ -3,6 +3,7 @@
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+ <meta encoding="utf8">
<link rel="stylesheet" href="llvm.css" type="text/css">
<title>LLVM 2.8 Release Notes</title>
</head>
@@ -19,7 +20,6 @@
<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>
@@ -28,11 +28,13 @@
<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">
@@ -66,23 +68,20 @@ current one. To see the release notes for a specific release, please see the
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:
+<!-- Features that need text if they're finished for 2.9:
combiner-aa?
strong phi elim
- llvm.dbg.value: variable debug info for optimized code
loop dependence analysis
TBAA
+ CorrelatedValuePropagation
-->
-
- <!-- for announcement email:
- Logo web page.
- Many new papers added to /pubs/
- -->
+
+ <!-- Announcement, lldb, libc++ -->
+
<!-- *********************************************************************** -->
<div class="doc_section">
@@ -115,13 +114,32 @@ 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>
+production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
+(32- and 64-bit), and for darwin-arm targets.</p>
<p>In the LLVM 2.8 time-frame, the Clang team has made many improvements:</p>
-<ul>
-
-</ul>
+ <ul>
+ <li>Clang C++ is now feature-complete with respect to the ISO C++ 1998 and 2003 standards.</li>
+ <li>Added support for Objective-C++.</li>
+ <li>Clang now uses LLVM-MC to directly generate object code and to parse inline assembly (on Darwin).</li>
+ <li>Introduced many new warnings, including <code>-Wmissing-field-initializers</code>, <code>-Wshadow</code>, <code>-Wno-protocol</code>, <code>-Wtautological-compare</code>, <code>-Wstrict-selector-match</code>, <code>-Wcast-align</code>, <code>-Wunused</code> improvements, and greatly improved format-string checking.</li>
+ <li>Introduced the "libclang" library, a C interface to Clang intended to support IDE clients.</li>
+ <li>Added support for <code>#pragma GCC visibility</code>, <code>#pragma align</code>, and others.</li>
+ <li>Added support for SSE, ARM NEON, and Altivec.</li>
+ <li>Improved support for many Microsoft extensions.</li>
+ <li>Implemented support for blocks in C++.</li>
+ <li>Implemented precompiled headers for C++.</li>
+ <li>Improved abstract syntax trees to retain more accurate source information.</li>
+ <li>Added driver support for handling LLVM IR and bitcode files directly.</li>
+ <li>Major improvements to compiler correctness for exception handling.</li>
+ <li>Improved generated code quality in some areas:
+ <ul>
+ <li>Good code generation for X86-32 and X86-64 ABI handling.</li>
+ <li>Improved code generation for bit-fields, although important work remains.</li>
+ </ul>
+ </li>
+ </ul>
</div>
<!--=========================================================================-->
@@ -138,27 +156,64 @@ production-quality compiler for C and Objective-C on x86 (32- and 64-bit).</p>
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>The LLVM 2.8 release fixes a number of bugs and slightly improves precision
+ over 2.7, but there are no major new features in the release.
</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
+<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</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>
+<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to
+gcc-4.5. Unlike llvm-gcc, dragonegg in theory does not require any gcc-4.5
+modifications whatsoever (currently one small patch is needed) thanks to the
+new <a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>.
+DragonEgg is a gcc plugin that makes gcc-4.5 use the LLVM optimizers and code
+generators instead of gcc's, just like with llvm-gcc.
+</p>
+
+<p>
+DragonEgg is still a work in progress, but it is able to compile a lot of code,
+for example all of gcc, LLVM and clang. Currently Ada, C, C++ and Fortran work
+well, while 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 may need additional gcc patches).
+</p>
+
+<p>
+The 2.8 release has the following notable changes:
+<ul>
+<li>The plugin loads faster due to exporting fewer symbols.</li>
+<li>Additional vector operations such as addps256 are now supported.</li>
+<li>Ada global variables with no initial value are no longer zero initialized,
+resulting in better optimization.</li>
+<li>The '-fplugin-arg-dragonegg-enable-gcc-optzns' flag now runs all gcc
+optimizers, rather than just a handful.</li>
+<li>Fortran programs using common variables now link correctly.</li>
+<li>GNU OMP constructs no longer crash the compiler.</li>
+</ul>
-<p>With the release of LLVM 2.8, ...</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 Java Virtual Machine (Java VM or JVM) that uses LLVM for static and
+just-in-time compilation. As of LLVM 2.8, VMKit now supports copying garbage
+collectors, and can be configured to use MMTk's copy mark-sweep garbage
+collector. In LLVM 2.8, the VMKit .NET VM is no longer being maintained.
+</p>
+</div>
<!--=========================================================================-->
<div class="doc_subsection">
@@ -178,67 +233,91 @@ 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>
+License, a "BSD-style" license. New in LLVM 2.8, compiler_rt now supports
+soft floating point (for targets that don't have a real floating point unit),
+and includes an extensive testsuite for the "blocks" language feature and the
+blocks runtime included in compiler_rt.</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a>
+<a name="lldb">LLDB: Low Level Debugger</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>
+<a href="http://lldb.llvm.org/">LLDB</a> is a brand new member of the LLVM
+umbrella of projects. LLDB is a next generation, high-performance debugger. It
+is built as a set of reusable components which highly leverage existing
+libraries in the larger LLVM Project, such as the Clang expression parser, the
+LLVM disassembler and the LLVM JIT.</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).
+LLDB is in early development and not included as part of the LLVM 2.8 release,
+but is mature enough to support basic debugging scenarios on Mac OS X in C,
+Objective-C and C++. We'd really like help extending and expanding LLDB to
+support new platforms, new languages, new architectures, and new features.
</p>
+</div>
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="libc++">libc++: C++ Standard Library</a>
+</div>
+
+<div class="doc_text">
+<p>
+<a href="http://libc++.llvm.org/">libc++</a> is another new member of the LLVM
+family. It is an implementation of the C++ standard library, written from the
+ground up to specifically target the forthcoming C++'0X standard and focus on
+delivering great performance.</p>
+
<p>
-2.8 status here.
+As of the LLVM 2.8 release, libc++ is virtually feature complete, but would
+benefit from more testing and better integration with Clang++. It is also
+looking forward to the C++ committee finalizing the C++'0x standard.
</p>
</div>
+
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="mc">llvm-mc: Machine Code Toolkit</a>
+<a name="klee">KLEE: A Symbolic Execution Virtual Machine</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>.
+<a href="http://klee.llvm.org/">KLEE</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 some algorithms.
</p>
-<p>2.8 status here</p>
-</div>
+<p>Although KLEE does not have any major new features as of 2.8, we have made
+various minor improvements, particular to ease development:</p>
+<ul>
+ <li>Added support for LLVM 2.8. KLEE currently maintains compatibility with
+ LLVM 2.6, 2.7, and 2.8.</li>
+ <li>Added a buildbot for 2.6, 2.7, and trunk. A 2.8 buildbot will be coming
+ soon following release.</li>
+ <li>Fixed many C++ code issues to allow building with Clang++. Mostly
+ complete, except for the version of MiniSAT which is inside the KLEE STP
+ version.</li>
+ <li>Improved support for building with separate source and build
+ directories.</li>
+ <li>Added support for "long double" on x86.</li>
+ <li>Initial work on KLEE support for using 'lit' test runner instead of
+ DejaGNU.</li>
+ <li>Added <tt>configure</tt> support for using an external version of
+ STP.</li>
+</ul>
+
+</div>
<!-- *********************************************************************** -->
@@ -254,298 +333,699 @@ LLVM MC Project Blog Post</a>.
projects that have already been updated to work with LLVM 2.8.</p>
</div>
-
-<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="whatsnew">What's New in LLVM 2.8?</a>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="tce">TTA-based Codesign Environment (TCE)</a>
</div>
-<!-- *********************************************************************** -->
<div class="doc_text">
+<p>
+<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing
+application-specific processors (ASP) based on the Transport triggered
+architecture (TTA). The toolset provides a complete co-design flow from C/C++
+programs down to synthesizable VHDL and parallel program binaries. Processor
+customization points include the register files, function units, supported
+operations, and the interconnection network.</p>
-<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>
+<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target
+independent optimizations and also for parts of code generation. It generates
+new LLVM-based code generators "on the fly" for the designed TTA processors and
+loads them in to the compiler backend as runtime libraries to avoid per-target
+recompilation of larger parts of the compiler chain.</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="orgchanges">LLVM Community Changes</a>
+<a name="Horizon">Horizon Bytecode Compiler</a>
</div>
<div class="doc_text">
+<p>
+<a href="http://www.quokforge.org/projects/horizon">Horizon</a> is a bytecode
+language and compiler written on top of LLVM, intended for producing
+single-address-space managed code operating systems that
+run faster than the equivalent multiple-address-space C systems.
+More in-depth blurb is available on the <a
+href="http://www.quokforge.org/projects/horizon/wiki/Wiki">wiki</a>.</p>
+
+</div>
-<p>In addition to changes to the code, between LLVM 2.7 and 2.8, a number of
-organization changes have happened:
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="clamav">Clam AntiVirus</a>
+</div>
+
+<div class="doc_text">
+<p>
+<a href="http://www.clamav.net">Clam AntiVirus</a> is an open source (GPL)
+anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail
+gateways. Since version 0.96 it has <a
+href="http://vrt-sourcefire.blogspot.com/2010/09/introduction-to-clamavs-low-level.html">bytecode
+signatures</a> that allow writing detections for complex malware. It
+uses LLVM's JIT to speed up the execution of bytecode on
+X86, X86-64, PPC32/64, falling back to its own interpreter otherwise.
+The git version was updated to work with LLVM 2.8.
</p>
-<ul>
-</ul>
+<p>The <a
+href="http://git.clamav.net/gitweb?p=clamav-bytecode-compiler.git;a=blob_plain;f=docs/user/clambc-user.pdf">
+ClamAV bytecode compiler</a> uses Clang and LLVM to compile a C-like
+language, insert runtime checks, and generate ClamAV bytecode.</p>
+
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="majorfeatures">Major New Features</a>
+<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>LLVM 2.8 includes several major new capabilities:</p>
-
-<ul>
-<li>.</li>
-</ul>
+<p>Pure versions 0.44 and later have been tested and are known to work with
+LLVM 2.8 (and continue to work with older LLVM releases >= 2.5).</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="coreimprovements">LLVM IR and Core Improvements</a>
+<a name="GHC">Glasgow Haskell Compiler (GHC)</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>
+<p>
+<a href="http://www.haskell.org/ghc/">GHC</a> is an open source,
+state-of-the-art programming suite for
+Haskell, a standard lazy functional programming language. It includes
+an optimizing static compiler generating good code for a variety of
+platforms, together with an interactive system for convenient, quick
+development.</p>
-<ul>
+<p>In addition to the existing C and native code generators, GHC 7.0 now
+supports an <a
+href="http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/Backends/LLVM">LLVM
+code generator</a>. GHC supports LLVM 2.7 and later.</p>
-<li>LLVM 2.8 changes the internal order of operands in <a
- href="http://llvm.org/doxygen/classllvm_1_1InvokeInst.html"><tt>InvokeInst</tt></a>
- and <a href="http://llvm.org/doxygen/classllvm_1_1CallInst.html"><tt>CallInst</tt></a>.
- To be portable across releases, resort to <tt>CallSite</tt> and the
- high-level accessors, such as <tt>getCalledValue</tt> and <tt>setUnwindDest</tt>.
-</li>
-<li>
- You can no longer pass use_iterators directly to cast<> (and similar), because
- these routines tend to perform costly dereference operations more than once. You
- have to dereference the iterators yourself and pass them in.
-</li>
-<li>
-The <tt>Pass(intptr_t)</tt> and <tt>Pass(const void*)</tt> got replaced with a
-<tt>Pass(char&amp;)</tt> constructor. This means you have to use ifdefs if you
-want your pass to work with both LLVM 2.7 and 2.8
-</li>
-<li>
- llvm.memcpy.*, llvm.memset.*, llvm.memmove.* (and possibly other?) intrinsics
- take an extra parameter now (i1 isVolatile), totaling 5 parameters.
- If you were creating these intrinsic calls and prototypes yourself (as opposed
- to using Intrinsic::getDeclaration), you can use UpgradeIntrinsicFunction/UpgradeIntrinsicCall
- to be portable accross releases.
- Note that you cannot use Intrinsic::getDeclaration() in a backwards compatible
- way (needs 2/3 types now, in 2.7 it needed just 1).
-</li>
-<li>
- SetCurrentDebugLocation takes a DebugLoc now instead of a MDNode.
- Change your code to use
- SetCurrentDebugLocation(DebugLoc::getFromDILocation(...)).
-</li>
-<li>
- VISIBILITY_HIDDEN is gone.
-</li>
-<li>
- The <tt>RegisterPass</tt> and <tt>RegisterAnalysisGroup</tt> templates are
- considered deprecated, but continue to function in LLVM 2.8. Clients are
- strongly advised to use the upcoming <tt>INITIALIZE_PASS()</tt> and
- <tt>INITIALIZE_AG_PASS()</tt> macros instead.
-<li>
- SMDiagnostic takes different parameters now. //FIXME: how to upgrade?
-</li>
-<li>
- The constructor for the Triple class no longer tries to understand odd triple
- specifications. Frontends should ensure that they only pass valid triples to
- LLVM. The Triple::normalize utility method has been added to help front-ends
- deal with funky triples.
-<li>
- Some APIs got renamed:
- <ul>
- <li>llvm_report_error -&gt; report_fatal_error</li>
- <li>llvm_install_error_handler -&gt; install_fatal_error_handler</li>
- <li>llvm::DwarfExceptionHandling -&gt; llvm::JITExceptionHandling</li>
- </ul>
- </li>
-</ul>
+</div>
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="Clay">Clay Programming Language</a>
+</div>
+
+<div class="doc_text">
+<p>
+<a href="http://tachyon.in/clay/">Clay</a> is a new systems programming
+language that is specifically designed for generic programming. It makes
+generic programming very concise thanks to whole program type propagation. It
+uses LLVM as its backend.</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="optimizer">Optimizer Improvements</a>
+<a name="llvm-py">llvm-py Python Bindings for LLVM</a>
</div>
<div class="doc_text">
+<p>
+<a href="http://www.mdevan.org/llvm-py/">llvm-py</a> has been updated to work
+with LLVM 2.8. llvm-py provides Python bindings for LLVM, allowing you to write a
+compiler backend or a VM in Python.</p>
-<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>
+</div>
-<ul>
-<li></li>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="FAUST">FAUST Real-Time Audio Signal Processing Language</a>
+</div>
+
+<div class="doc_text">
+<p>
+<a href="http://faust.grame.fr">FAUST</a> is a compiled language for real-time
+audio signal processing. The name FAUST stands for Functional AUdio STream. Its
+programming model combines two approaches: functional programming and block
+diagram composition. In addition with the C, C++, JAVA output formats, the
+Faust compiler can now generate LLVM bitcode, and works with LLVM 2.7 and
+2.8.</p>
-</ul>
+</div>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="jade">Jade Just-in-time Adaptive Decoder Engine</a>
</div>
+<div class="doc_text">
+<p><a
+href="http://sourceforge.net/apps/trac/orcc/wiki/JadeDocumentation">Jade</a>
+(Just-in-time Adaptive Decoder Engine) is a generic video decoder engine using
+LLVM for just-in-time compilation of video decoder configurations. Those
+configurations are designed by MPEG Reconfigurable Video Coding (RVC) committee.
+MPEG RVC standard is built on a stream-based dataflow representation of
+decoders. It is composed of a standard library of coding tools written in
+RVC-CAL language and a dataflow configuration &#8212; block diagram &#8212;
+of a decoder.</p>
+
+<p>Jade project is hosted as part of the <a href="http://orcc.sf.net">Open
+RVC-CAL Compiler</a> and requires it to translate the RVC-CAL standard library
+of video coding tools into an LLVM assembly code.</p>
+
+</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="executionengine">Interpreter and JIT Improvements</a>
+<a name="neko_llvm_jit">LLVM JIT for Neko VM</a>
</div>
<div class="doc_text">
+<p><a href="http://github.com/vava/neko_llvm_jit">Neko LLVM JIT</a>
+replaces the standard Neko JIT with an LLVM-based implementation. While not
+fully complete, it is already providing a 1.5x speedup on 64-bit systems.
+Neko LLVM JIT requires LLVM 2.8 or later.</p>
-<ul>
-<li></li>
+</div>
-</ul>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="crack">Crack Scripting Language</a>
+</div>
+
+<div class="doc_text">
+<p>
+<a href="http://code.google.com/p/crack-language/">Crack</a> aims to provide
+the ease of development of a scripting language with the performance of a
+compiled language. The language derives concepts from C++, Java and Python,
+incorporating object-oriented programming, operator overloading and strong
+typing. Crack 0.2 works with LLVM 2.7, and the forthcoming Crack 0.2.1 release
+builds on LLVM 2.8.</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="codegen">Target Independent Code Generator Improvements</a>
+<a name="DresdenTM">Dresden TM Compiler (DTMC)</a>
</div>
<div class="doc_text">
+<p>
+<a href="http://tm.inf.tu-dresden.de">DTMC</a> provides support for
+Transactional Memory, which is an easy-to-use and efficient way to synchronize
+accesses to shared memory. Transactions can contain normal C/C++ code (e.g.,
+<code>__transaction { list.remove(x); x.refCount--; }</code>) and will be executed
+virtually atomically and isolated from other transactions.</p>
-<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>
+</div>
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="Kai">Kai Programming Language</a>
+</div>
+
+<div class="doc_text">
+<p>
+<a href="http://www.oriontransfer.co.nz/research/kai">Kai</a> (Japanese 会 for
+meeting/gathering) is an experimental interpreter that provides a highly
+extensible runtime environment and explicit control over the compilation
+process. Programs are defined using nested symbolic expressions, which are all
+parsed into first-class values with minimal intrinsic semantics. Kai can
+generate optimised code at run-time (using LLVM) in order to exploit the nature
+of the underlying hardware and to integrate with external software libraries.
+It is a unique exploration into world of dynamic code compilation, and the
+interaction between high level and low level semantics.</p>
-<ul>
-<li>MachO writer works.</li>
-</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="x86">X86-32 and X86-64 Target Improvements</a>
+<a name="OSL">OSL: Open Shading Language</a>
</div>
<div class="doc_text">
-<p>New features of the X86 target include:
+<p>
+<a href="http://code.google.com/p/openshadinglanguage/">OSL</a> is a shading
+language designed for use in physically based renderers and in particular
+production rendering. By using LLVM instead of the interpreter, it was able to
+meet its performance goals (&gt;= C-code) while retaining the benefits of
+runtime specialization and a portable high-level language.
</p>
-<ul>
-<li>The X86 backend now supports holding X87 floating point stack values
- in registers across basic blocks, dramatically improving performance of code
- that uses long double, and when targetting CPUs that don't support SSE.</li>
+</div>
-</ul>
+
+
+<!-- *********************************************************************** -->
+<div class="doc_section">
+ <a name="whatsnew">What's New in LLVM 2.8?</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="ARM">ARM Target Improvements</a>
+<a name="majorfeatures">Major New Features</a>
</div>
<div class="doc_text">
-<p>New features of the ARM target include:
-</p>
+
+<p>LLVM 2.8 includes several major new capabilities:</p>
<ul>
+<li>As mentioned above, <a href="#libc++">libc++</a> and <a
+ href="#lldb">LLDB</a> are major new additions to the LLVM collective.</li>
+<li>LLVM 2.8 now has pretty decent support for debugging optimized code. You
+ should be able to reliably get debug info for function arguments, assuming
+ that the value is actually available where you have stopped.</li>
+<li>A new 'llvm-diff' tool is available that does a semantic diff of .ll
+ files.</li>
+<li>The <a href="#mc">MC subproject</a> has made major progress in this release.
+ Direct .o file writing support for darwin/x86[-64] is now reliable and
+ support for other targets and object file formats are in progress.</li>
+</ul>
-<li></li>
+</div>
-</ul>
+<!--=========================================================================-->
+<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#int_libc">memcpy, memmove, and memset</a>
+ intrinsics now take address space qualified pointers and a bit to indicate
+ whether the transfer is "<a href="LangRef.html#volatile">volatile</a>" or not.
+</li>
+<li>Per-instruction debug info metadata is much faster and uses less memory by
+ using the new DebugLoc class.</li>
+<li>LLVM IR now has a more formalized concept of "<a
+ href="LangRef.html#trapvalues">trap values</a>", which allow the optimizer
+ to optimize more aggressively in the presence of undefined behavior, while
+ still producing predictable results.</li>
+<li>LLVM IR now supports two new <a href="LangRef.html#linkage">linkage
+ types</a> (linker_private_weak and linker_private_weak_def_auto) which map
+ onto some obscure MachO concepts.</li>
+</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="newapis">New Useful APIs</a>
+<a name="optimizer">Optimizer Improvements</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>
+<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></li>
+<li>As mentioned above, the optimizer now has support for updating debug
+ information as it goes. A key aspect of this is the new <a
+ href="SourceLevelDebugging.html#format_common_value">llvm.dbg.value</a>
+ intrinsic. This intrinsic represents debug info for variables that are
+ promoted to SSA values (typically by mem2reg or the -scalarrepl passes).</li>
+
+<li>The JumpThreading pass is now much more aggressive about implied value
+ relations, allowing it to thread conditions like "a == 4" when a is known to
+ be 13 in one of the predecessors of a block. It does this in conjunction
+ with the new LazyValueInfo analysis pass.</li>
+<li>The new RegionInfo analysis pass identifies single-entry single-exit regions
+ in the CFG. You can play with it with the "opt -regions analyze" or
+ "opt -view-regions" commands.</li>
+<li>The loop optimizer has significantly improved strength reduction and analysis
+ capabilities. Notably it is able to build on the trap value and signed
+ integer overflow information to optimize &lt;= and &gt;= loops.</li>
+<li>The CallGraphSCCPassManager now has some basic support for iterating within
+ an SCC when a optimizer devirtualizes a function call. This allows inlining
+ through indirect call sites that are devirtualized by store-load forwarding
+ and other optimizations.</li>
+<li>The new <A href="Passes.html#loweratomic">-loweratomic</a> pass is available
+ to lower atomic instructions into their non-atomic form. This can be useful
+ to optimize generic code that expects to run in a single-threaded
+ environment.</li>
</ul>
+<!--
+<p>In addition to these features that are done in 2.8, there is preliminary
+ support in the release for Type Based Alias Analysis
+ Preliminary work on TBAA but not usable in 2.8.
+ New CorrelatedValuePropagation pass, not on by default in 2.8 yet.
+-->
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="otherimprovements">Other Improvements and New Features</a>
+<a name="mc">MC Level Improvements</a>
</div>
<div class="doc_text">
-<p>Other miscellaneous features include:</p>
+<p>
+The LLVM Machine Code (aka MC) subsystem 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.</p>
+
+<p>The MC subproject has made great leaps in LLVM 2.8. For example, support for
+ directly writing .o files from LLC (and clang) now works reliably for
+ darwin/x86[-64] (including inline assembly support) and the integrated
+ assembler is turned on by default in Clang for these targets. This provides
+ improved compile times among other things.</p>
<ul>
-<li></li>
+<li>The entire compiler has converted over to using the MCStreamer assembler API
+ instead of writing out a .s file textually.</li>
+<li>The "assembler parser" is far more mature than in 2.7, supporting a full
+ complement of directives, now supports assembler macros, etc.</li>
+<li>The "assembler backend" has been completed, including support for relaxation
+ relocation processing and all the other things that an assembler does.</li>
+<li>The MachO file format support is now fully functional and works.</li>
+<li>The MC disassembler now fully supports ARM and Thumb. ARM assembler support
+ is still in early development though.</li>
+<li>The X86 MC assembler now supports the X86 AES and AVX instruction set.</li>
+<li>Work on ELF and COFF object files and ARM target support is well underway,
+ but isn't useful yet in LLVM 2.8. Please contact the llvmdev mailing list
+ if you're interested in this.</li>
</ul>
-</div>
+<p>For more information, 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>
+
+</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="changes">Major Changes and Removed Features</a>
+<a name="codegen">Target Independent Code Generator Improvements</a>
</div>
<div class="doc_text">
-<p>If you're already an LLVM user or developer with out-of-tree changes based
-on LLVM 2.7, this section lists some "gotchas" that you may run into upgrading
-from the previous release.</p>
+<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