<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
- <link rel="stylesheet" href="llvm.css" type="text/css">
- <title>LLVM 3.0 Release Notes</title>
+ <link rel="stylesheet" href="_static/llvm.css" type="text/css">
+ <title>LLVM 3.1 Release Notes</title>
</head>
<body>
-<h1>LLVM 3.0 Release Notes</h1>
+<h1>LLVM 3.1 Release Notes</h1>
-<img align=right src="http://llvm.org/img/DragonSmall.png"
- width="136" height="136" alt="LLVM Dragon Logo">
+<div>
+<img style="float:right" src="http://llvm.org/img/DragonSmall.png"
+ width="136" height="136" alt="LLVM Dragon Logo">
+</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 3.0</a></li>
- <li><a href="#whatsnew">What's New in LLVM 3.0?</a></li>
+ <li><a href="#externalproj">External Projects Using LLVM 3.1</a></li>
+ <li><a href="#whatsnew">What's New in LLVM?</a></li>
<li><a href="GettingStarted.html">Installation Instructions</a></li>
<li><a href="#knownproblems">Known Problems</a></li>
<li><a href="#additionalinfo">Additional Information</a></li>
<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 3.0
+<h1 style="color:red">These are in-progress notes for the upcoming LLVM 3.1
release.<br>
You may prefer the
-<a href="http://llvm.org/releases/2.9/docs/ReleaseNotes.html">LLVM 2.9
+<a href="http://llvm.org/releases/3.0/docs/ReleaseNotes.html">LLVM 3.0
Release Notes</a>.</h1>
- -->
<!-- *********************************************************************** -->
<h2>
<div>
<p>This document contains the release notes for the LLVM Compiler
- Infrastructure, release 3.0. Here we describe the status of LLVM, including
+ Infrastructure, release 3.1. Here we describe the status of LLVM, including
major improvements from the previous release, improvements in various
subprojects of LLVM, and some of the current users of the code.
All LLVM releases may be downloaded from
<div>
-<p>The LLVM 3.0 distribution currently consists of code from the core LLVM
+<p>The LLVM 3.1 distribution currently consists of code from the core LLVM
repository (which roughly includes the LLVM optimizers, code generators and
- supporting tools), and the Clang 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>
+ supporting tools), and the Clang 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>
<!--=========================================================================-->
<h3>
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 3.0 time-frame, the Clang team has made many improvements:</p>
-
+<p>In the LLVM 3.1 time-frame, the Clang team has made many improvements.
+ Highlights include:</p>
<ul>
- <li>Greatly improved support for building C++ applications, with greater
- stability and better diagnostics.</li>
-
- <li><a href="http://clang.llvm.org/cxx_status.html">Improved support</a> for
- the <a href="http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=50372">C++
- 2011</a> standard (aka "C++'0x"), including implementations of non-static data member
- initializers, alias templates, delegating constructors, range-based
- for loops, and implicitly-generated move constructors and move assignment
- operators, among others.</li>
-
- <li>Implemented support for some features of the upcoming C1x standard,
- including static assertions and generic selections.</li>
-
- <li>Better detection of include and linking paths for system headers and
- libraries, especially for Linux distributions.</li>
-
- <li>Several improvements to Objective-C support, including:
-
- <ul>
- <li><a href="http://clang.llvm.org/docs/AutomaticReferenceCounting.html">
- Automatic Reference Counting</a> (ARC) and an improved memory model
- cleanly separating object and C memory.</li>
-
- <li>A migration tool for moving manual retain/release code to ARC</li>
-
- <li>Better support for data hiding, allowing instance variables to be
- declared in implementation contexts or class extensions</li>
- <li>Weak linking support for Objective-C classes</li>
- <li>Improved static type checking by inferring the return type of methods
- such as +alloc and -init.</li>
- </ul>
-
- Some new Objective-C features require either the Mac OS X 10.7 / iOS 5
- Objective-C runtime, or version 1.6 or later of the GNUstep Objective-C
- runtime version.</li>
-
- <li>Improved support for OpenCL C, including the <tt>vec_step</tt> operator,
- address space qualifiers, improved vector literal support and code
- generation support for the <a href="#PTX">PTX target</a>.</li>
-
- <li>Implemented a number of optimizations in <tt>libclang</tt>, the Clang C
- interface, to improve the performance of code completion and the mapping
- from source locations to abstract syntax tree nodes.</li>
+ <li>Greatly expanded <a href="http://clang.llvm.org/cxx_status.html">C++11
+ support</a> including lambdas, initializer lists, constexpr, user-defined
+ literals, and atomics.</li>
+ <li>A new <a href="http://clang.llvm.org/docs/Tooling.html">tooling</a>
+ library to ease building of clang-based standalone tools.</li>
+ <li>Extended support for
+ <a href="http://clang.llvm.org/docs/ObjectiveCLiterals.html">literals in
+ Objective C</a>.</li>
</ul>
+<p>For more details about the changes to Clang since the 3.0 release, see the
+ <a href="http://clang.llvm.org/docs/ReleaseNotes.html">Clang release
+ notes.</a></p>
<p>If Clang rejects your code but another compiler accepts it, please take a
look at the <a href="http://clang.llvm.org/compatibility.html">language
</h3>
<div>
+
<p><a href="http://dragonegg.llvm.org/">DragonEgg</a> is a
<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin</a> that replaces GCC's
- optimizers and code generators with LLVM's. It works with gcc-4.5 or gcc-4.6,
- targets the x86-32 and x86-64 processor families, and has been successfully
- used on the Darwin, FreeBSD, KFreeBSD, Linux and OpenBSD platforms. It fully
- supports Ada, C, C++ and Fortran. It has partial support for Go, Java, Obj-C
- and Obj-C++.</p>
+ optimizers and code generators with LLVM's. It works with gcc-4.5 and gcc-4.6
+ (and partially with gcc-4.7), can target the x86-32/x86-64 and ARM processor
+ families, and has been successfully used on the Darwin, FreeBSD, KFreeBSD,
+ Linux and OpenBSD platforms. It fully supports Ada, C, C++ and Fortran. It
+ has partial support for Go, Java, Obj-C and Obj-C++.</p>
-<p>The 3.0 release has the following notable changes:</p>
+<p>The 3.1 release has the following notable changes:</p>
- <ul>
- <li>GCC version 4.6 is now fully supported.</li>
+<ul>
+ <li>Partial support for gcc-4.7. Ada support is poor, but other languages work
+ fairly well.</li>
- <li>Patching and building GCC is no longer required: the plugin should work
- with your system GCC (version 4.5 or 4.6; on Debian/Ubuntu systems the
- gcc-4.5-plugin-dev or gcc-4.6-plugin-dev package is also needed).</li>
+ <li>Support for ARM processors. Some essential gcc headers that are needed to
+ build DragonEgg for ARM are not installed by gcc. To work around this,
+ copy the missing headers from the gcc source tree.</li>
- <li>The <tt>-fplugin-arg-dragonegg-enable-gcc-optzns</tt> option, which runs
- GCC's optimizers as well as LLVM's, now works much better. This is the
- option to use if you want ultimate performance! It is still experimental
- though: it may cause the plugin to crash.</li>
+ <li>Better optimization for Fortran by exploiting the fact that Fortran scalar
+ arguments have 'restrict' semantics.</li>
- <li>The type and constant conversion logic has been almost entirely rewritten,
- fixing a multitude of obscure bugs.</li>
+ <li>Better optimization for all languages by passing information about type
+ aliasing and type ranges to the LLVM optimizers.</li>
+ <li>A regression test-suite was added.</li>
</ul>
</div>
implementations of this and other low-level routines (some are 3x faster than
the equivalent libgcc routines).</p>
-<p>In the LLVM 3.0 timeframe, the target specific ARM code has converted to
- "unified" assembly syntax, and several new functions have been added to the
- library.</p>
-
</div>
<!--=========================================================================-->
<div>
-<p>LLDB is a ground-up implementation of a command line debugger, as well as a
- debugger API that can be used from other applications. LLDB makes use of the
- Clang parser to provide high-fidelity expression parsing (particularly for
- C++) and uses the LLVM JIT for target support.</p>
-
-<p>LLDB has advanced by leaps and bounds in the 3.0 timeframe. It is
- dramatically more stable and useful, and includes both a
- new <a href="http://lldb.llvm.org/tutorial.html">tutorial</a> and
- a <a href="http://lldb.llvm.org/lldb-gdb.html">side-by-side comparison with
- GDB</a>.</p>
+<p><a href="http://lldb.llvm.org">LLDB</a> is a ground-up implementation of a
+ command line debugger, as well as a debugger API that can be used from other
+ applications. LLDB makes use of the Clang parser to provide high-fidelity
+ expression parsing (particularly for C++) and uses the LLVM JIT for target
+ support.</p>
</div>
licensed</a> under the MIT and UIUC license, allowing it to be used more
permissively.</p>
-<p>Libc++ has been ported to FreeBSD and imported into the base system. It is
- planned to be the default STL implementation for FreeBSD 10.</p>
-
</div>
<!--=========================================================================-->
<div>
- <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.
-
- <p>In the LLVM 3.0 time-frame, VMKit has had significant improvements on both
- runtime and startup performance:</p>
-
- <ul>
- <li>Precompilation: by compiling ahead of time a small subset of Java's core
- library, the startup performance have been highly optimized to the point that
- running a 'Hello World' program takes less than 30 milliseconds.</li>
+<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.</p>
- <li>Customization: by customizing virtual methods for individual classes,
- the VM can statically determine the target of a virtual call, and decide to
- inline it.</li>
-
- <li>Inlining: the VM does more inlining than it did before, by allowing more
- bytecode instructions to be inlined, and thanks to customization. It also
- inlines GC barriers, and object allocations.</li>
-
- <li>New exception model: the generated code for a method that does not do
- any try/catch is not penalized anymore by the eventuality of calling a
- method that throws an exception. Instead, the method that throws the
- exception jumps directly to the method that could catch it.</li>
- </ul>
+<p>In the LLVM 3.1 time-frame, VMKit has had significant improvements on both
+ runtime and startup performance.</p>
</div>
<!--=========================================================================-->
<h3>
-<a name="LLBrowse">LLBrowse: IR Browser</a>
+<a name="Polly">Polly: Polyhedral Optimizer</a>
</h3>
<div>
-<p><a href="http://llvm.org/svn/llvm-project/llbrowse/trunk/doc/LLBrowse.html">
- LLBrowse</a> is an interactive viewer for LLVM modules. It can load any LLVM
- module and displays its contents as an expandable tree view, facilitating an
- easy way to inspect types, functions, global variables, or metadata nodes. It
- is fully cross-platform, being based on the popular wxWidgets GUI
- toolkit.</p>
-
-</div>
+<p><a href="http://polly.llvm.org/">Polly</a> is an <em>experimental</em>
+ optimizer for data locality and parallelism. It currently provides high-level
+ loop optimizations and automatic parallelisation (using the OpenMP run time).
+ Work in the area of automatic SIMD and accelerator code generation was
+ started.</p>
+<p>Within the LLVM 3.1 time-frame there were the following highlights:</p>
-<!--=========================================================================-->
-<!--
-<h3>
-<a name="klee">KLEE: A Symbolic Execution Virtual Machine</a>
-</h3>
-
-<div>
-<p>
-<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>
+<ul>
+ <li>Polly became an official LLVM project</li>
+ <li>Polly can be loaded directly into clang (enabled by '-O3 -mllvm -polly')</li>
+ <li>An automatic scheduling optimizer (derived
+ from <a href="http://pluto-compiler.sourceforge.net/">Pluto</a>) was
+ integrated. It performs loop transformations to optimize for data-locality
+ and parallelism. The transformations include, but are not limited to
+ interchange, fusion, fission, skewing and tiling.</li>
+</ul>
-<p>UPDATE!</p>
-</div>-->
+</div>
</div>
<!-- *********************************************************************** -->
<h2>
- <a name="externalproj">External Open Source Projects Using LLVM 3.0</a>
+ <a name="externalproj">External Open Source Projects Using LLVM 3.1</a>
</h2>
<!-- *********************************************************************** -->
<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 3.0.</p>
-
-<!--=========================================================================-->
-<h3>AddressSanitizer</h3>
-
-<div>
-
-<p><a href="http://code.google.com/p/address-sanitizer/">AddressSanitizer</a>
- uses compiler instrumentation and a specialized malloc library to find C/C++
- bugs such as use-after-free and out-of-bound accesses to heap, stack, and
- globals. The key feature of the tool is speed: the average slowdown
- introduced by AddressSanitizer is less than 2x.</p>
-
-</div>
-
-<!--=========================================================================-->
-<h3>ClamAV</h3>
-
-<div>
-
-<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.</p>
-
-<p>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 3.0.</p>
-
-</div>
-
-<!--=========================================================================-->
-<h3>clang_complete for VIM</h3>
-
-<div>
-
-<p><a href="https://github.com/Rip-Rip/clang_complete">clang_complete</a> is a
- VIM plugin, that provides accurate C/C++ autocompletion using the clang front
- end. The development version of clang complete, can directly use libclang
- which can maintain a cache to speed up auto completion.</p>
-
-</div>
-
-<!--=========================================================================-->
-<h3>clReflect</h3>
-
-<div>
-
-<p><a href="https://bitbucket.org/dwilliamson/clreflect">clReflect</a> is a C++
- parser that uses clang/LLVM to derive a light-weight reflection database
- suitable for use in game development. It comes with a very simple runtime
- library for loading and querying the database, requiring no external
- dependencies (including CRT), and an additional utility library for object
- management and serialisation.</p>
-
-</div>
-
-<!--=========================================================================-->
-<h3>Cling C++ Interpreter</h3>
-
-<div>
-
-<p><a href="http://cern.ch/cling">Cling</a> is an interactive compiler interface
- (aka C++ interpreter). It supports C++ and C, and uses LLVM's JIT and the
- Clang parser. It has a prompt interface, runs source files, calls into shared
- libraries, prints the value of expressions, even does runtime lookup of
- identifiers (dynamic scopes). And it just behaves like one would expect from
- an interpreter.</p>
-
-</div>
-
-<!--=========================================================================-->
-<h3>Crack Programming Language</h3>
+ projects that have already been updated to work with LLVM 3.1.</p>
-<div>
-
-<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.</p>
-
-</div>
-
-<!--=========================================================================-->
-<h3>Eero</h3>
-
-<div>
-
-<p><a href="http://eerolanguage.org/">Eero</a> is a fully
- header-and-binary-compatible dialect of Objective-C 2.0, implemented with a
- patched version of the Clang/LLVM compiler. It features a streamlined syntax,
- Python-like indentation, and new operators, for improved readability and
- reduced code clutter. It also has new features such as limited forms of
- operator overloading and namespaces, and strict (type-and-operator-safe)
- enumerations. It is inspired by languages such as Smalltalk, Python, and
- Ruby.</p>
-
-</div>
-
-<!--=========================================================================-->
-<h3>FAUST Real-Time Audio Signal Processing Language</h3>
+<h3>FAUST</h3>
<div>
<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 2.7-3.0.
- </p>
+ 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,
+ JavaScript output formats, the Faust compiler can generate LLVM bitcode, and
+ works with LLVM 2.7-3.1.</p>
</div>
-<!--=========================================================================-->
<h3>Glasgow Haskell Compiler (GHC)</h3>
<div>
-<p>GHC 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>
+<p><a href="http://www.haskell.org/ghc/">GHC</a> is an open source compiler and
+ programming suite for Haskell, a 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>
<p>GHC 7.0 and onwards include an LLVM code generator, supporting LLVM 2.8 and
- later. Since LLVM 2.9, GHC now includes experimental support for the ARM
- platform with LLVM 3.0.</p>
-
-</div>
-
-<!--=========================================================================-->
-<h3>gwXscript</h3>
-
-<div>
-
-<p><a href="http://botwars.tk/gwscript/">gwXscript</a> is an object oriented,
- aspect oriented programming language which can create both executables (ELF,
- EXE) and shared libraries (DLL, SO, DYNLIB). The compiler is implemented in
- its own language and translates scripts into LLVM-IR which can be optimized
- and translated into native code by the LLVM framework. Source code in
- gwScript contains definitions that expand the namespaces. So you can build
- your project and simply 'plug out' features by removing a file. The remaining
- project does not leave scars since you directly separate concerns by the
- 'template' feature of gwX. It is also possible to add new features to a
- project by just adding files and without editing the original project. This
- language is used for example to create games or content management systems
- that should be extendable.</p>
-
-<p>gwXscript is strongly typed and offers comfort with its native types string,
- hash and array. You can easily write new libraries in gwXscript or native
- code. gwXscript is type safe and users should not be able to crash your
- program or execute malicious code except code that is eating CPU time.</p>
-
-</div>
-
-<!--=========================================================================-->
-<h3>include-what-you-use</h3>
-
-<div>
-
-<p><a href="http://code.google.com/p/include-what-you-use">include-what-you-use</a>
- is a tool to ensure that a file directly <code>#include</code>s
- all <code>.h</code> files that provide a symbol that the file uses. It also
- removes superfluous <code>#include</code>s from source files.</p>
+ later.</p>
</div>
-<!--=========================================================================-->
-<h3>ispc: The Intel SPMD Program Compiler</h3>
+<h3>Julia</h3>
<div>
-<p><a href="http://ispc.github.com">ispc</a> is a compiler for "single program,
- multiple data" (SPMD) programs. It compiles a C-based SPMD programming
- language to run on the SIMD units of CPUs; it often delivers 5-6x speedups on
- a single core of a CPU with an 8-wide SIMD unit compared to serial code,
- while still providing a clean and easy-to-understand programming model. For
- an introduction to the language and its performance,
- see <a href="http://ispc.github.com/example.html">the walkthrough</a> of a short
- example program. ispc is licensed under the BSD license.</p>
-
-</div>
-
-<!--=========================================================================-->
-<h3>The Julia Programming Language</h3>
-
-<div>
+<p><a href="https://github.com/JuliaLang/julia">Julia</a> is a high-level,
+ high-performance dynamic language for technical computing. It provides a
+ sophisticated compiler, distributed parallel execution, numerical accuracy,
+ and an extensive mathematical function library. The compiler uses type
+ inference to generate fast code without any type declarations, and uses
+ LLVM's optimization passes and JIT compiler. The
+ <a href="http://julialang.org/"> Julia Language</a> is designed
+ around multiple dispatch, giving programs a large degree of flexibility. It
+ is ready for use on many kinds of problems.</p>
-<p><a href="http://github.com/JuliaLang/julia">Julia</a> is a high-level,
- high-performance dynamic language for technical
- computing. It provides a sophisticated compiler, distributed parallel
- execution, numerical accuracy, and an extensive mathematical function
- library. The compiler uses type inference to generate fast code
- without any type declarations, and uses LLVM's optimization passes and
- JIT compiler. The language is designed around multiple dispatch,
- giving programs a large degree of flexibility. It is ready for use on many
- kinds of problems.</p>
</div>
-<!--=========================================================================-->
-<h3>LanguageKit and Pragmatic Smalltalk</h3>
+<h3>LLVM D Compiler</h3>
<div>
-<p><a href="http://etoileos.com/etoile/features/languagekit/">LanguageKit</a> is
- a framework for implementing dynamic languages sharing an object model with
- Objective-C. It provides static and JIT compilation using LLVM along with
- its own interpreter. Pragmatic Smalltalk is a dialect of Smalltalk, built on
- top of LanguageKit, that interfaces directly with Objective-C, sharing the
- same object representation and message sending behaviour. These projects are
- developed as part of the Étoilé desktop environment.</p>
+<p><a href="https://github.com/ldc-developers/ldc">LLVM D Compiler</a> (LDC) is
+ a compiler for the D programming Language. It is based on the DMD frontend
+ and uses LLVM as backend.</p>
</div>
-<!--=========================================================================-->
-<h3>LuaAV</h3>
+<h3>Open Shading Language</h3>
<div>
-<p><a href="http://lua-av.mat.ucsb.edu/blog/">LuaAV</a> is a real-time
- audiovisual scripting environment based around the Lua language and a
- collection of libraries for sound, graphics, and other media protocols. LuaAV
- uses LLVM and Clang to JIT compile efficient user-defined audio synthesis
- routines specified in a declarative syntax.</p>
+<p><a href="https://github.com/imageworks/OpenShadingLanguage/">Open Shading
+ Language (OSL)</a> is a small but rich language for programmable shading in
+ advanced global illumination renderers and other applications, ideal for
+ describing materials, lights, displacement, and pattern generation. It uses
+ LLVM to JIT complex shader networks to x86 code at runtime.</p>
-</div>
-
-<!--=========================================================================-->
-<h3>Mono</h3>
-
-<div>
-
-<p>An open source, cross-platform implementation of C# and the CLR that is
- binary compatible with Microsoft.NET. Has an optional, dynamically-loaded
- LLVM code generation backend in Mini, the JIT compiler.</p>
-
-<p>Note that we use a Git mirror of LLVM <a
- href="https://github.com/mono/llvm">with some patches</a>.</p>
+<p>OSL was developed by Sony Pictures Imageworks for use in its in-house
+ renderer used for feature film animation and visual effects, and is
+ distributed as open source software with the "New BSD" license.</p>
</div>
-<!--=========================================================================-->
-<h3>Polly</h3>
-
-<div>
-
-<p><a href="http://polly.grosser.es">Polly</a> is an advanced data-locality
- optimizer and automatic parallelizer. It uses an advanced, mathematical
- model to calculate detailed data dependency information which it uses to
- optimize the loop structure of a program. Polly can speed up sequential code
- by improving memory locality and consequently the cache use. Furthermore,
- Polly is able to expose different kind of parallelism which it exploits by
- introducing (basic) OpenMP and SIMD code. A mid-term goal of Polly is to
- automatically create optimized GPU code.</p>
-
-</div>
-
-<!--=========================================================================-->
<h3>Portable OpenCL (pocl)</h3>
<div>
-<p>Portable OpenCL is an open source implementation of the OpenCL standard which
- can be easily adapted for new targets. One of the goals of the project is
- improving performance portability of OpenCL programs, avoiding the need for
- target-dependent manual optimizations. A "native" target is included, which
- allows running OpenCL kernels on the host (CPU).</p>
+<p>In addition to producing an easily portable open source OpenCL
+ implementation, another major goal of <a href="http://pocl.sourceforge.net/">
+ pocl</a> is improving performance portability of OpenCL programs with
+ compiler optimizations, reducing the need for target-dependent manual
+ optimizations. An important part of pocl is a set of LLVM passes used to
+ statically parallelize multiple work-items with the kernel compiler, even in
+ the presence of work-group barriers. This enables static parallelization of
+ the fine-grained static concurrency in the work groups in multiple ways
+ (SIMD, VLIW, superscalar,...).</p>
</div>
-<!--=========================================================================-->
<h3>Pure</h3>
<div>
-<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. The interpreter uses LLVM as a backend to JIT-compile Pure
- programs to fast native code. 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 interface to C and other programming
- languages (including the ability to load LLVM bitcode modules, and inline C,
- C++, Fortran and Faust code in Pure programs if the corresponding LLVM-enabled
- compilers are installed).</p>
-
-<p>Pure version 0.48 has been tested and is known to work with LLVM 3.0
- (and continues to work with older LLVM releases >= 2.5).</p>
-
-</div>
-
-<!--=========================================================================-->
-<h3>Renderscript</h3>
-
-<div>
-
-<p><a href="http://developer.android.com/guide/topics/renderscript/index.html">Renderscript</a>
- is Android's advanced 3D graphics rendering and compute API. It provides a
- portable C99-based language with extensions to facilitate common use cases
- for enhancing graphics and thread level parallelism. The Renderscript
- compiler frontend is based on Clang/LLVM. It emits a portable bitcode format
- for the actual compiled script code, as well as reflects a Java interface for
- developers to control the execution of the compiled bitcode. Executable
- machine code is then generated from this bitcode by an LLVM backend on the
- device. Renderscript is thus able to provide a mechanism by which Android
- developers can improve performance of their applications while retaining
- portability.</p>
-
-</div>
-
-<!--=========================================================================-->
-<h3>SAFECode</h3>
-
-<div>
-
-<p><a href="http://safecode.cs.illinois.edu">SAFECode</a> is a memory safe C/C++
- compiler built using LLVM. It takes standard, unannotated C/C++ code,
- analyzes the code to ensure that memory accesses and array indexing
- operations are safe, and instruments the code with run-time checks when
- safety cannot be proven statically. SAFECode can be used as a debugging aid
- (like Valgrind) to find and repair memory safety bugs. It can also be used
- to protect code from security attacks at run-time.</p>
-
-</div>
-<!--=========================================================================-->
-<h3>The Stupid D Compiler (SDC)</h3>
-
-<div>
+<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. The interpreter uses LLVM as a backend to JIT-compile Pure
+ programs to fast native code. 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 interface to C and other programming
+ languages (including the ability to load LLVM bitcode modules, and inline C,
+ C++, Fortran and Faust code in Pure programs if the corresponding
+ LLVM-enabled compilers are installed).</p>
-<p><a href="https://github.com/bhelyer/SDC">The Stupid D Compiler</a> is a
- project seeking to write a self-hosting compiler for the D programming
- language without using the frontend of the reference compiler (DMD).</p>
+<p>Pure version 0.54 has been tested and is known to work with LLVM 3.1 (and
+ continues to work with older LLVM releases >= 2.5).</p>
</div>
-<!--=========================================================================-->
<h3>TTA-based Co-design Environment (TCE)</h3>
<div>
-<p>TCE 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><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/Verilog and parallel program binaries.
+ Processor customization points include the register files, function units,
+ supported operations, and the interconnection network.</p>
<p>TCE uses Clang and LLVM for C/C++ language support, target independent
optimizations and also for parts of code generation. It generates new
</div>
-<!--=========================================================================-->
-<h3>Tart Programming Language</h3>
-
-<div>
-
-<p><a href="http://code.google.com/p/tart/">Tart</a> is a general-purpose,
- strongly typed programming language designed for application
- developers. Strongly inspired by Python and C#, Tart focuses on practical
- solutions for the professional software developer, while avoiding the clutter
- and boilerplate of legacy languages like Java and C++. Although Tart is still
- in development, the current implementation supports many features expected of
- a modern programming language, such as garbage collection, powerful
- bidirectional type inference, a greatly simplified syntax for template
- metaprogramming, closures and function literals, reflection, operator
- overloading, explicit mutability and immutability, and much more. Tart is
- flexible enough to accommodate a broad range of programming styles and
- philosophies, while maintaining a strong commitment to simplicity, minimalism
- and elegance in design.</p>
-
-</div>
-
-<!--=========================================================================-->
-<h3>ThreadSanitizer</h3>
-
-<div>
-
-<p><a href="http://code.google.com/p/data-race-test/">ThreadSanitizer</a> is a
- data race detector for (mostly) C and C++ code, available for Linux, Mac OS
- and Windows. On different systems, we use binary instrumentation frameworks
- (Valgrind and Pin) as frontends that generate the program events for the race
- detection algorithm. On Linux, there's an option of using LLVM-based
- compile-time instrumentation.</p>
-
-</div>
-
</div>
<!-- *********************************************************************** -->
<h2>
- <a name="whatsnew">What's New in LLVM 3.0?</a>
+ <a name="whatsnew">What's New in LLVM 3.1?</a>
</h2>
<!-- *********************************************************************** -->
llvm/lib/Archive - replace with lib object?
-->
-<p>LLVM 3.0 includes several major changes and big features:</p>
+<p>LLVM 3.1 includes several major changes and big features:</p>
<ul>
-<li>llvm-gcc is no longer supported, and not included in the release. We
- recommend switching to <a
- href="http://clang.llvm.org/">Clang</a> or <a
- href="http://dragonegg.llvm.org/">DragonEgg</a>.</li>
-
-<li>The linear scan register allocator has been replaced with a new "greedy"
- register allocator, enabling live range splitting and many other
- optimizations that lead to better code quality. Please see its <a
- href="http://blog.llvm.org/2011/09/greedy-register-allocation-in-llvm-30.html">blog post</a> or its talk at the <a
- href="http://llvm.org/devmtg/2011-11/">Developer Meeting</a>
- for more information.</li>
-<li>LLVM IR now includes full support for <a href="Atomics.html">atomics
- memory operations</a> intended to support the C++'11 and C'1x memory models.
- This includes <a href="LangRef.html#memoryops">atomic load and store,
- compare and exchange, and read/modify/write instructions</a> as well as a
- full set of <a href="LangRef.html#ordering">memory ordering constraints</a>.
- Please see the <a href="Atomics.html">Atomics Guide</a> for more
- information.
-</li>
-<li>The LLVM IR exception handling representation has been redesigned and
- reimplemented, making it more elegant, fixing a huge number of bugs, and
- enabling inlining and other optimizations. Please see its blog post (XXX
- not yet) and the <a href="ExceptionHandling.html">Exception Handling
- documentation</a> for more information.</li>
-<li>The LLVM IR Type system has been redesigned and reimplemented, making it
- faster and solving some long-standing problems.
- Please see its <a
- href="http://blog.llvm.org/2011/11/llvm-30-type-system-rewrite.html">blog
- post</a> for more information.</li>
-
-<li>The MIPS backend has made major leaps in this release, going from an
- experimental target to being virtually production quality and supporting a
- wide variety of MIPS subtargets. See the <a href="#MIPS">MIPS section</a>
- below for more information.</li>
-
-<li>The optimizer and code generator now supports gprof and gcov-style coverage
- and profiling information, and includes a new llvm-cov tool (but also works
- with gcov). Clang exposes coverage and profiling through GCC-compatible
- command line options.</li>
+ <li><a href="../tools/clang/docs/AddressSanitizer.html">AddressSanitizer</a>,
+ a fast memory error detector.</li>
+ <li><a href="CodeGenerator.html#machineinstrbundle">MachineInstr Bundles</a>,
+ Support to model instruction bundling / packing.</li>
+ <li><a href="#armintegratedassembler">ARM Integrated Assembler</a>,
+ A full featured assembler and direct-to-object support for ARM.</li>
+ <li><a href="#blockplacement">Basic Block Placement</a>
+ Probability driven basic block placement.</li>
</ul>
</div>
<p>LLVM IR has several new features for better support of new targets and that
expose new optimization opportunities:</p>
- <ul>
- <li><a href="Atomics.html">Atomic memory accesses and memory ordering</a> are
- now directly expressible in the IR.</li>
- <li>A new <a href="LangRef.html#int_fma">llvm.fma intrinsic</a> directly
- represents floating point multiply accumulate operations without an
- intermediate rounding stage.</li>
- <li>A new llvm.expect intrinsic (XXX not documented in langref) allows a
- frontend to express expected control flow (and the __builtin_expect builtin
- from GNU C).</li>
- <li>The <a href="LangRef.html#int_prefetch">llvm.prefetch intrinsic</a> now
- takes a 4th argument that specifies whether the prefetch happens from the
- icache or dcache.</li>
- <li>The new <a href="LangRef.html#uwtable">uwtable function attribute</a>
- allows a frontend to control emission of unwind tables.</li>
- <li>The new <a href="LangRef.html#fnattrs">nonlazybind function
- attribute</a> allow optimization of Global Offset Table (GOT) accesses.</li>
- <li>The new <a href="LangRef.html#returns_twice">returns_twice attribute</a>
- allows better modeling of functions like setjmp.</li>
- <li>The <a href="LangRef.html#datalayout">target datalayout</a> string can now
- encode the natural alignment of the target's stack for better optimization.
- </li>
- </ul>
+<ul>
+ <li>A new type representing 16 bit <i>half</i> floating point values has
+ been added.</li>
+ <li>IR now supports vectors of pointers, including vector GEPs.</li>
+ <li>Module flags have been introduced. They convey information about the
+ module as a whole to LLVM subsystems. This is currently used to encode
+ Objective C ABI information.</li>
+ <li>Loads can now have range metadata attached to them to describe the
+ possible values being loaded.</li>
+ <li>The <tt>llvm.ctlz</tt> and <tt>llvm.cttz</tt> intrinsics now have an
+ additional argument which indicates whether the behavior of the intrinsic
+ is undefined on a zero input. This can be used to generate more efficient
+ code on platforms that only have instructions which don't return the type
+ size when counting bits in 0.</li>
+</ul>
+
</div>
<!--=========================================================================-->
optimizers:</p>
<ul>
-<li>The pass manager now has an extension API that allows front-ends and plugins
- to insert their own optimizations in the well-known places in the standard
- pass optimization pipeline.</li>
-
-<li>Information about <a href="BranchWeightMetadata.html">branch probability</a>
- and basic block frequency is now available within LLVM, based on a
- combination of static branch prediction heuristics and
- <code>__builtin_expect</code> calls. That information is currently used for
- register spill placement and if-conversion, with additional optimizations
- planned for future releases. The same framework is intended for eventual
- use with profile-guided optimization.</li>
-
-<li>The "-indvars" induction variable simplification pass only modifies
- induction variables when profitable. Sign and zero extension
- elimination, linear function test replacement, loop unrolling, and
- other simplifications that require induction variable analysis have
- been generalized so they no longer require loops to be rewritten into
- canonical form prior to optimization. This new design
- preserves more IR level information, avoids undoing earlier loop
- optimizations (particularly hand-optimized loops), and no longer
- requires the code generator to reconstruct loops into an optimal form -
- an intractable problem.</li>
-
-<li>LLVM now includes a pass to optimize retain/release calls for the
- <a href="http://clang.llvm.org/docs/AutomaticReferenceCounting.html">Automatic
- Reference Counting</a> (ARC) Objective-C language feature (in
- lib/Transforms/Scalar/ObjCARC.cpp). It is a decent example of implementing
- a source-language-specific optimization in LLVM.</li>
-
+ <li>The loop unroll pass now is able to unroll loops with run-time trip counts.
+ This feature is turned off by default, and is enabled with the
+ <code>-unroll-runtime</code> flag.</li>
+ <li>A new basic-block autovectorization pass is available. Pass
+ <code>-vectorize</code> to run this pass along with some associated
+ post-vectorization cleanup passes. For more information, see the EuroLLVM
+ 2012 slides: <a href="http://llvm.org/devmtg/2012-04-12/Slides/Hal_Finkel.pdf">
+ Autovectorization with LLVM</a>.</li>
+ <li>Inline cost heuristics have been completely overhauled and now closely
+ model constant propagation through call sites, disregard trivially dead
+ code costs, and can model C++ STL iterator patterns.</li>
</ul>
</div>
to the LLVM MC Project Blog Post</a>.</p>
<ul>
- <li>The MC layer has undergone significant refactoring to eliminate layering
- violations that caused it to pull in the LLVM compiler backend code.</li>
- <li>The ELF object file writers are much more full featured.</li>
- <li>The integrated assembler now supports #line directives.</li>
- <li>An early implementation of a JIT built on top of the MC framework (known
- as MC-JIT) has been implemented and will eventually replace the old JIT.
- It emits object files direct to memory and uses a runtime dynamic linker to
- resolve references and drive lazy compilation. The MC-JIT enables much
- greater code reuse between the JIT and the static compiler and provides
- better integration with the platform ABI as a result.
- </li>
- <li>The assembly printer now makes uses of assemblers instruction aliases
- (InstAliases) to print simplified mneumonics when possible.</li>
- <li>TableGen can now autogenerate MC expansion logic for pseudo
- instructions that expand to multiple MC instructions (through the
- PseudoInstExpansion class).</li>
- <li>A new llvm-dwarfdump tool provides a start of a drop-in
- replacement for the corresponding tool that use LLVM libraries. As part of
- this, LLVM has the beginnings of a dwarf parsing library.</li>
- <li>llvm-objdump has more output including, symbol by symbol disassembly,
- inline relocations, section headers, symbol tables, and section contents.
- Support for archive files has also been added.</li>
- <li>llvm-nm has gained support for archives of binary files.</li>
- <li>llvm-size has been added. This tool prints out section sizes.</li>
+ <li>The integrated assembler can optionally emit debug information when
+ assembling a </tt>.s</tt> file. It can be enabled by passing the
+ <tt>-g</tt> option to <tt>llvm-mc</tt>.</li>
</ul>
</div>
<div>
+<p>We have changed the way that the Type Legalizer legalizes vectors. The type
+ legalizer now attempts to promote integer elements. This enabled the
+ implementation of vector-select. Additionally, we see a performance boost on
+ workloads which use vectors of chars and shorts, since they are now promoted
+ to 32-bit types, which are better supported by the SIMD instruction set.
+ Floating point types are still widened as before.</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>
-<li>XXX: Segmented stacks.</li>
-<li>LLVM generates substantially better code for indirect gotos due to a new
- tail duplication pass, which can be a substantial performance win for
- interpreter loops that use them.</li>
-<li>Exception handling and debug information is now emitted with CFI directives,
- yielding <a href="http://blog.mozilla.com/respindola/2011/05/12/cfi-directives/">much smaller executables</a> for some C++ applications.
-</li>
-
-<li>The code generator now supports vector "select" operations on vector
- comparisons, turning them into various optimized code sequences (e.g.
- using the SSE4/AVX "blend" instructions).</li>
-<li>The SSE execution domain fix pass and the ARM NEON move fix pass have been
- merged to a target independent execution dependency fix pass. This pass is
- used to select alternative equivalent opcodes in a way that minimizes
- execution domain crossings. Closely connected instructions are moved to
- the same execution domain when possible. Targets can override the
- <code>getExecutionDomain</code> and <code>setExecutionDomain</code> hooks
- to use the pass.</li>
+ <li>TableGen can now synthesize register classes that are only needed to
+ represent combinations of constraints from instructions and sub-registers.
+ The synthetic register classes inherit most of their properties form their
+ closest user-defined super-class.</li>
+ <li><code>MachineRegisterInfo</code> now allows the reserved registers to be
+ frozen when register allocation starts. Target hooks should use the
+ <code>MRI->canReserveReg(FramePtr)</code> method to avoid accidentally
+ disabling frame pointer elimination during register allocation.</li>
+ <li>A new kind of <code>MachineOperand</code> provides a compact
+ representation of large clobber lists on call instructions. The register
+ mask operand references a bit mask of preserved registers. Everything else
+ is clobbered.</li>
+ <li>The DWARF debug info writer gained support for emitting data for the
+ <a href="SourceLevelDebugging.html#acceltable">name accelerator tables
+ DWARF extension</a>. It is used by LLDB to speed up name lookup.</li>
</ul>
+
+<p> We added new TableGen infrastructure to support bundling for
+ Very Long Instruction Word (VLIW) architectures. TableGen can now
+ automatically generate a deterministic finite automaton from a VLIW
+ target's schedule description which can be queried to determine
+ legal groupings of instructions in a bundle.</p>
+
+<p> We have added a new target independent VLIW packetizer based on the
+ DFA infrastructure to group machine instructions into bundles.</p>
+
+</div>
+
+<h4>
+<a name="blockplacement">Basic Block Placement</a>
+</h4>
+<div>
+<p>A probability based block placement and code layout algorithm was added to
+LLVM's code generator. This layout pass supports probabilities derived from
+static heuristics as well as source code annotations such as
+<code>__builtin_expect</code>.</p>
</div>
<!--=========================================================================-->
<p>New features and major changes in the X86 target include:</p>
<ul>
-<li>The X86 backend, assembler and disassembler now have full support for AVX 1.
- To enable it pass <code>-mavx</code> to the compiler. AVX2 implementation is
- underway on mainline.</li>
-<li>The integrated assembler and disassembler now support a broad range of new
- instructions including Atom, Ivy Bridge, <a
- href="http://en.wikipedia.org/wiki/SSE4a">SSE4a/BMI</a> instructions, <a
- href="http://en.wikipedia.org/wiki/RdRand">rdrand</a> and many others.</li>
-<li>The X86 backend now fully supports the <a href="http://llvm.org/PR879">X87
- floating point stack inline assembly constraints</a>.</li>
-<li>The integrated assembler now supports the <tt>.code32</tt> and
- <tt>.code64</tt> directives to switch between 32-bit and 64-bit
- instructions.</li>
-<li>The X86 backend now synthesizes horizontal add/sub instructions from generic
- vector code when the appropriate instructions are enabled.</li>
-<li>The X86-64 backend generates smaller and faster code at -O0 due to
- improvements in fast instruction selection.</li>
-<li><a href="http://code.google.com/p/nativeclient/">Native Client</a>
- subtarget support has been added.</li>
-
-<li>The CRC32 intrinsics have been renamed. The intrinsics were previously
- <code>@llvm.x86.sse42.crc32.[8|16|32]</code>
- and <code>@llvm.x86.sse42.crc64.[8|64]</code>. They have been renamed to
- <code>@llvm.x86.sse42.crc32.32.[8|16|32]</code> and
- <code>@llvm.x86.sse42.crc32.64.[8|64]</code>.</li>
+ <li>Greatly improved support for AVX2.</li>
+ <li>Lots of bug fixes and improvements for AVX1.</li>
+ <li>Support for the FMA4 and XOP instruction set extensions.</li>
+ <li>Call instructions use the new register mask operands for faster compile
+ times and better support for different calling conventions. The old WINCALL
+ instructions are no longer needed.</li>
+ <li>DW2 Exception Handling is enabled on Cygwin and MinGW.</li>
+ <li>Support for implicit TLS model used with MSVC runtime.</li>
</ul>
</div>
<p>New features of the ARM target include:</p>
<ul>
-<li>The ARM backend generates much faster code for Cortex-A9 chips.</li>
-<li>The ARM backend has improved support for Cortex-M series processors.</li>
-<li>The ARM inline assembly constraints have been implemented and are now fully
- supported.</li>
-<li>NEON code produced by Clang often runs much faster due to improvements in
- the Scalar Replacement of Aggregates pass.</li>
-<li>The old ARM disassembler is replaced with a new one based on autogenerated
- encoding information from ARM .td files.</li>
-<li>The integrated assembler has made major leaps forward, but is still beta quality in LLVM 3.0.</li>
+ <li>The constant island pass now supports basic block and constant pool entry
+ alignments greater than 4 bytes.</li>
+ <li>On Darwin, the ARM target now has a full-featured integrated assembler.
+ </li>
</ul>
-</div>
+<h4>
+<a name="armintegratedassembler">ARM Integrated Assembler</a>
+</h4>
+<div>
+<p>The ARM target now includes a full featured macro assembler, including
+direct-to-object module support for clang. The assembler is currently enabled
+by default for Darwin only pending testing and any additional necessary
+platform specific support for Linux.</p>
+
+<p>Full support is included for Thumb1, Thumb2 and ARM modes, along with
+subtarget and CPU specific extensions for VFP2, VFP3 and NEON.</p>
+
+<p>The assembler is Unified Syntax only (see ARM Architecural Reference Manual
+for details). While there is some, and growing, support for pre-unfied (divided)
+syntax, there are still significant gaps in that support.</p>
+</div>
+</div>
<!--=========================================================================-->
<h3>
<a name="MIPS">MIPS Target Improvements</a>
</h3>
<div>
-
-<p>This release has seen major new work on just about every aspect of the MIPS
- backend. Some of the major new features include:</p>
+New features and major changes in the MIPS target include:</p>
<ul>
- <li>Most MIPS32r1 and r2 instructions are now supported.</li>
- <li>LE/BE MIPS32r1/r2 has been tested extensively.</li>
- <li>O32 ABI has been fully tested.</li>
- <li>MIPS backend has migrated to using the MC infrastructure for assembly printing. Initial support for direct object code emission has been implemented too.</li>
- <li>Delay slot filler has been updated. Now it tries to fill delay slots with useful instructions instead of always filling them with NOPs.</li>
- <li>Support for old-style JIT is complete.</li>
- <li>Support for old architectures (MIPS1 and MIPS2) has been removed.</li>
- <li>Initial support for MIPS64 has been added.</li>
+ <li>MIPS32 little-endian direct object code emission is functional.</li>
+ <li>MIPS64 little-endian code generation is largely functional for N64 ABI in assembly printing mode with the exception of handling of long double (f128) type.</li>
+ <li>Support for new instructions has been added, which includes swap-bytes
+ instructions (WSBH and DSBH), floating point multiply-add/subtract and
+ negative multiply-add/subtract instructions, and floating
+ point load/store instructions with reg+reg addressing (LWXC1, etc.)</li>
+ <li>Various fixes to improve performance have been implemented.</li>
+ <li>Post-RA scheduling is now enabled at -O3.</li>
+ <li>Support for soft-float code generation has been added.</li>
</ul>
</div>
<!--=========================================================================-->
<h3>
-
<a name="PTX">PTX Target Improvements</a>
+<a name="PTX">PTX Target Improvements</a>
</h3>
<div>
- <p>
- The PTX back-end is still experimental, but is fairly usable for compute kernels
- in LLVM 3.0. Most scalar arithmetic is implemented, as well as intrinsics to
- access the special PTX registers and sync instructions. The major missing
- pieces are texture/sampler support and some vector operations.</p>
+<p>An outstanding conditional inversion bug was fixed in this release.</p>
- <p>That said, the backend is already being used for domain-specific languages
- and works well with the <a href="http://www.pcc.me.uk/~peter/libclc/">libclc
- library</a> to supply OpenCL built-ins. With it, you can use Clang to compile
- OpenCL code into PTX and execute it by loading the resulting PTX as a binary
- blob using the nVidia OpenCL library. It has been tested with several OpenCL
- programs, including some from the nVidia GPU Computing SDK, and the performance
- is on par with the nVidia compiler.</p>
+<p><b>NOTE</b>: LLVM 3.1 marks the last release of the PTX back-end, in its
+ current form. The back-end is currently being replaced by the NVPTX
+ back-end, currently in SVN ToT.</p>
</div>
<div>
<ul>
-<li>Many PowerPC improvements have been implemented for ELF targets, including
- support for varargs and initial support for direct .o file emission.</li>
-
-<li>MicroBlaze scheduling itineraries were added that model the
- 3-stage and the 5-stage pipeline architectures. The 3-stage
- pipeline model can be selected with <code>-mcpu=mblaze3</code>
- and the 5-stage pipeline model can be selected with
- <code>-mcpu=mblaze5</code>.</li>
-
+ <li>Support for Qualcomm's Hexagon VLIW processor has been added.</li>
</ul>
</div>
<div>
<p>If you're already an LLVM user or developer with out-of-tree changes based on
- LLVM 2.9, this section lists some "gotchas" that you may run into upgrading
+ LLVM 3.1, this section lists some "gotchas" that you may run into upgrading
from the previous release.</p>
<ul>
-<li>LLVM 3.0 removes support for reading LLVM 2.8 and earlier files, and LLVM
- 3.1 will eliminate support for reading LLVM 2.9 files. Going forward, we
- aim for all future versions of LLVM to read bitcode files and .ll files
- produced by LLVM 3.0.</li>
-<li>Tablegen has been split into a library, allowing the clang tblgen pieces
- now live in the clang tree. The llvm version has been renamed to
- llvm-tblgen instead of tblgen.</li>
- <li>The <code>LLVMC</code> meta compiler driver was removed.</li>
- <li>The unused PostOrder Dominator Frontiers and LowerSetJmp passes were removed.</li>
-
-
- <li>The old <code>TailDup</code> pass was not used in the standard pipeline
- and was unable to update ssa form, so it has been removed.
- <li>The syntax of volatile loads and stores in IR has been changed to
- "<code>load volatile</code>"/"<code>store volatile</code>". The old
- syntax ("<code>volatile load</code>"/"<code>volatile store</code>")
- is still accepted, but is now considered deprecated and will be removed in
- 3.1.</li>
- <li>llvm-gcc's frontend tests have been removed from llvm/test/Frontend*, sunk
- into the clang and dragonegg testsuites.</li>
- <li>The old atomic intrinsics (<code>llvm.memory.barrier</code> and
- <code>llvm.atomic.*</code>) are now gone. Please use the new atomic
- instructions, described in the <a href="Atomics.html">atomics guide</a>.
- <li>LLVM's configure script doesn't depend on llvm-gcc anymore, eliminating a
- strange circular dependence between projects.</li>
-</ul>
-
-<h4>Windows (32-bit)</h4>
-<div>
-
-<ul>
- <li>On Win32(MinGW32 and MSVC), Windows 2000 will not be supported.
- Windows XP or higher is required.</li>
+ <li>LLVM's build system now requires a python 2 interpreter to be present at
+ build time. A perl interpreter is no longer required.</li>
+ <li>The C backend has been removed. It had numerous problems, to the point of
+ not being able to compile any nontrivial program.</li>
+ <li>The Alpha, Blackfin and SystemZ targets have been removed due to lack of
+ maintenance.</li>
+ <li>LLVM 3.1 removes support for reading LLVM 2.9 bitcode files. Going
+ forward, we aim for all future versions of LLVM to read bitcode files and
+ <tt>.ll</tt> files produced by LLVM 3.0 and later.</li>
+ <li>The <tt>unwind</tt> instruction is now gone. With the introduction of the
+ new exception handling system in LLVM 3.0, the <tt>unwind</tt> instruction
+ became obsolete.</li>
+ <li>LLVM 3.0 and earlier automatically added the returns_twice fo functions
+ like setjmp based on the name. This functionality was removed in 3.1.
+ This affects Clang users, if -ffreestanding is used.</li>
</ul>
</div>
-</div>
-
<!--=========================================================================-->
<h3>
<a name="api_changes">Internal API Changes</a>
LLVM API changes are:</p>
<ul>
- <li>The biggest and most pervasive change is that llvm::Types are no longer
- returned or accepted as 'const' values. Instead, just pass around
- non-const Types.</li>
-
- <li><code>PHINode::reserveOperandSpace</code> has been removed. Instead, you
- must specify how many operands to reserve space for when you create the
- PHINode, by passing an extra argument
- into <code>PHINode::Create</code>.</li>
-
- <li>PHINodes no longer store their incoming BasicBlocks as operands. Instead,
- the list of incoming BasicBlocks is stored separately, and can be accessed
- with new functions <code>PHINode::block_begin</code>
- and <code>PHINode::block_end</code>.</li>
-
- <li>Various functions now take an <code>ArrayRef</code> instead of either a
- pair of pointers (or iterators) to the beginning and end of a range, or a
- pointer and a length. Others now return an <code>ArrayRef</code> instead
- of a reference to a <code>SmallVector</code>
- or <code>std::vector</code>. These include:
+ <li>Target specific options have been moved from global variables to members
+ on the new <code>TargetOptions</code> class, which is local to each
+ <code>TargetMachine</code>. As a consequence, the associated flags will
+ no longer be accepted by <tt>clang -mllvm</tt>. This includes:
<ul>
-<!-- Please keep this list sorted. -->
-<li><code>CallInst::Create</code></li>
-<li><code>ComputeLinearIndex</code> (in <code>llvm/CodeGen/Analysis.h</code>)</li>
-<li><code>ConstantArray::get</code></li>
-<li><code>ConstantExpr::getExtractElement</code></li>
-<li><code>ConstantExpr::getGetElementPtr</code></li>
-<li><code>ConstantExpr::getInBoundsGetElementPtr</code></li>
-<li><code>ConstantExpr::getIndices</code></li>
-<li><code>ConstantExpr::getInsertElement</code></li>
-<li><code>ConstantExpr::getWithOperands</code></li>
-<li><code>ConstantFoldCall</code> (in <code>llvm/Analysis/ConstantFolding.h</code>)</li>
-<li><code>ConstantFoldInstOperands</code> (in <code>llvm/Analysis/ConstantFolding.h</code>)</li>
-<li><code>ConstantVector::get</code></li>
-<li><code>DIBuilder::createComplexVariable</code></li>
-<li><code>DIBuilder::getOrCreateArray</code></li>
-<li><code>ExtractValueInst::Create</code></li>
-<li><code>ExtractValueInst::getIndexedType</code></li>
-<li><code>ExtractValueInst::getIndices</code></li>
-<li><code>FindInsertedValue</code> (in <code>llvm/Analysis/ValueTracking.h</code>)</li>
-<li><code>gep_type_begin</code> (in <code>llvm/Support/GetElementPtrTypeIterator.h</code>)</li>
-<li><code>gep_type_end</code> (in <code>llvm/Support/GetElementPtrTypeIterator.h</code>)</li>
-<li><code>GetElementPtrInst::Create</code></li>
-<li><code>GetElementPtrInst::CreateInBounds</code></li>
-<li><code>GetElementPtrInst::getIndexedType</code></li>
-<li><code>InsertValueInst::Create</code></li>
-<li><code>InsertValueInst::getIndices</code></li>
-<li><code>InvokeInst::Create</code></li>
-<li><code>IRBuilder::CreateCall</code></li>
-<li><code>IRBuilder::CreateExtractValue</code></li>
-<li><code>IRBuilder::CreateGEP</code></li>
-<li><code>IRBuilder::CreateInBoundsGEP</code></li>
-<li><code>IRBuilder::CreateInsertValue</code></li>
-<li><code>IRBuilder::CreateInvoke</code></li>
-<li><code>MDNode::get</code></li>
-<li><code>MDNode::getIfExists</code></li>
-<li><code>MDNode::getTemporary</code></li>
-<li><code>MDNode::getWhenValsUnresolved</code></li>
-<li><code>SimplifyGEPInst</code> (in <code>llvm/Analysis/InstructionSimplify.h</code>)</li>
-<li><code>TargetData::getIndexedOffset</code></li>
+<li><code>llvm::PrintMachineCode</code></li>
+<li><code>llvm::NoFramePointerElim</code></li>
+<li><code>llvm::NoFramePointerElimNonLeaf</code></li>
+<li><code>llvm::DisableFramePointerElim(const MachineFunction &)</code></li>
+<li><code>llvm::LessPreciseFPMADOption</code></li>
+<li><code>llvm::LessPrecideFPMAD()</code></li>
+<li><code>llvm::NoExcessFPPrecision</code></li>
+<li><code>llvm::UnsafeFPMath</code></li>
+<li><code>llvm::NoInfsFPMath</code></li>
+<li><code>llvm::NoNaNsFPMath</code></li>
+<li><code>llvm::HonorSignDependentRoundingFPMathOption</code></li>
+<li><code>llvm::HonorSignDependentRoundingFPMath()</code></li>
+<li><code>llvm::UseSoftFloat</code></li>
+<li><code>llvm::FloatABIType</code></li>
+<li><code>llvm::NoZerosInBSS</code></li>
+<li><code>llvm::JITExceptionHandling</code></li>
+<li><code>llvm::JITEmitDebugInfo</code></li>
+<li><code>llvm::JITEmitDebugInfoToDisk</code></li>
+<li><code>llvm::GuaranteedTailCallOpt</code></li>
+<li><code>llvm::StackAlignmentOverride</code></li>
+<li><code>llvm::RealignStack</code></li>
+<li><code>llvm::DisableJumpTables</code></li>
+<li><code>llvm::EnableFastISel</code></li>
+<li><code>llvm::getTrapFunctionName()</code></li>
+<li><code>llvm::EnableSegmentedStacks</code></li>
</ul></li>
- <li>All forms of <code>StringMap::getOrCreateValue</code> have been remove
- except for the one which takes a <code>StringRef</code>.</li>
+ <li>The <code>MDBuilder</code> class has been added to simplify the creation
+ of metadata.</li>
+</ul>
+
+</div>
- <li>The <code>LLVMBuildUnwind</code> function from the C API was removed. The
- LLVM <code>unwind</code> instruction has been deprecated for a long time
- and isn't used by the current front-ends. So this was removed during the
- exception handling rewrite.</li>
+<!--=========================================================================-->
+<h3>
+<a name="tools_changes">Tools Changes</a>
+</h3>
- <li>The <code>LLVMAddLowerSetJmpPass</code> function from the C API was
- removed because the <code>LowerSetJmp</code> pass was removed.</li>
+<div>
- <li>The <code>DIBuilder</code> interface used by front ends to encode
- debugging information in the LLVM IR now expects clients to
- use <code>DIBuilder::finalize()</code> at the end of translation unit to
- complete debugging information encoding.</li>
+<p>In addition, some tools have changed in this release. Some of the changes
+ are:</p>
- <li>The way the type system works has been
- rewritten: <code>PATypeHolder</code> and <code>OpaqueType</code> are gone,
- and all APIs deal with <code>Type*</code> instead of <code>const
- Type*</code>. If you need to create recursive structures, then create a
- named structure, and use <code>setBody()</code> when all its elements are
- built. Type merging and refining is gone too: named structures are not
- merged with other structures, even if their layout is identical. (of
- course anonymous structures are still uniqued by layout).</li>
- <li>TargetSelect.h moved to Support/ from Target/</li>
+<ul>
+ <li><tt>llvm-stress</tt> is a command line tool for generating random
+ <tt>.ll</tt> files to fuzz different LLVM components. </li>
+ <li>The <tt>llvm-ld</tt> tool has been removed. The clang driver provides a
+ more reliable solution for turning a set of bitcode files into a binary.
+ To merge bitcode files <tt>llvm-link</tt> can be used instead.</li>
+</ul>
- <li>UpgradeIntrinsicCall no longer upgrades pre-2.9 intrinsic calls (for
- example <code>llvm.memset.i32</code>).</li>
+</div>
- <li>It is mandatory to initialize all out-of-tree passes too and their dependencies now with
- <code>INITIALIZE_PASS{BEGIN,END,}</code>
- and <code>INITIALIZE_{PASS,AG}_DEPENDENCY</code>.</li>
- <li>The interface for MemDepResult in MemoryDependenceAnalysis has been
- enhanced with new return types Unknown and NonFuncLocal, in addition to
- the existing types Clobber, Def, and NonLocal.</li>
+<!--=========================================================================-->
+<h3>
+<a name="python">Python Bindings</a>
+</h3>
+
+<div>
+
+<p>Officially supported Python bindings have been added! Feature support is far
+from complete. The current bindings support interfaces to:</p>
+<ul>
+ <li>Object File Interface</li>
+ <li>Disassembler</li>
</ul>
+<p>Using the Object File Interface, it is possible to inspect binary object files.
+Think of it as a Python version of readelf or llvm-objdump.</p>
+
+<p>Support for additional features is currently being developed by community
+contributors. If you are interested in shaping the direction of the Python
+bindings, please express your intent on IRC or the developers list.</p>
+
</div>
</div>
<p>Known problem areas include:</p>
<ul>
- <li>The Alpha, Blackfin, CellSPU, MSP430, PTX, SystemZ and
- XCore backends are experimental, and the Alpha, Blackfin and SystemZ
- targets have already been removed from mainline.</li>
+ <li>The CellSPU, MSP430, PTX and XCore backends are experimental.</li>
<li>The integrated assembler, disassembler, and JIT is not supported by
several targets. If an integrated assembler is not supported, then a
system assembler is required. For more details, see the <a
href="CodeGenerator.html#targetfeatures">Target Features Matrix</a>.
</li>
-
- <li>The C backend has numerous problems and is not being actively maintained.
- Depending on it for anything serious is not advised.</li>
</ul>
</div>
-</div>
-
<!-- *********************************************************************** -->
<h2>
<a name="additionalinfo">Additional Information</a>
</div>
-<!--=========================================================================-->
-
-<!-- EH details: to be moved to a blog post:
-
-
-
-
-<p>One of the biggest changes is that 3.0 has a new exception handling
- system. The old system used LLVM intrinsics to convey the exception handling
- information to the code generator. It worked in most cases, but not
- all. Inlining was especially difficult to get right. Also, the intrinsics
- could be moved away from the <code>invoke</code> instruction, making it hard
- to recover that information.</p>
-
-<p>The new EH system makes exception handling a first-class member of the IR. It
- adds two new instructions:</p>
-
-<ul>
- <li><a href="LangRef.html#i_landingpad"><code>landingpad</code></a> —
- this instruction defines a landing pad basic block. It contains all of the
- information that's needed by the code generator. It's also required to be
- the first non-PHI instruction in the landing pad. In addition, a landing
- pad may be jumped to only by the unwind edge of an <code>invoke</code>
- instruction.</li>
-
- <li><a href="LangRef.html#i_resume"><code>resume</code></a> — this
- instruction causes the current exception to resume traveling up the
- stack. It replaces the <code>@llvm.eh.resume</code> intrinsic.</li>
-</ul>
-
-<p>Converting from the old EH API to the new EH API is rather simple, because a
- lot of complexity has been removed. The two intrinsics,
- <code>@llvm.eh.exception</code> and <code>@llvm.eh.selector</code> have been
- superseded by the <code>landingpad</code> instruction. Instead of generating
- a call to <code>@llvm.eh.exception</code> and <code>@llvm.eh.selector</code>:
-
-<div class="doc_code">
-<pre>
-Function *ExcIntr = Intrinsic::getDeclaration(TheModule,
- Intrinsic::eh_exception);
-Function *SlctrIntr = Intrinsic::getDeclaration(TheModule,
- Intrinsic::eh_selector);
-
-// The exception pointer.
-Value *ExnPtr = Builder.CreateCall(ExcIntr, "exc_ptr");
-
-std::vector<Value*> Args;
-Args.push_back(ExnPtr);
-Args.push_back(Builder.CreateBitCast(Personality,
- Type::getInt8PtrTy(Context)));
-
-<i>// Add selector clauses to Args.</i>
-
-// The selector call.
-Builder.CreateCall(SlctrIntr, Args, "exc_sel");
-</pre>
-</div>
-
-<p>You should instead generate a <code>landingpad</code> instruction, that
- returns an exception object and selector value:</p>
-
-<div class="doc_code">
-<pre>
-LandingPadInst *LPadInst =
- Builder.CreateLandingPad(StructType::get(Int8PtrTy, Int32Ty, NULL),
- Personality, 0);
-
-Value *LPadExn = Builder.CreateExtractValue(LPadInst, 0);
-Builder.CreateStore(LPadExn, getExceptionSlot());
-
-Value *LPadSel = Builder.CreateExtractValue(LPadInst, 1);
-Builder.CreateStore(LPadSel, getEHSelectorSlot());
-</pre>
-</div>
-
-<p>It's now trivial to add the individual clauses to the <code>landingpad</code>
- instruction.</p>
-
-<div class="doc_code">
-<pre>
-<i><b>// Adding a catch clause</b></i>
-Constant *TypeInfo = getTypeInfo();
-LPadInst->addClause(TypeInfo);
-
-<i><b>// Adding a C++ catch-all</b></i>
-LPadInst->addClause(Constant::getNullValue(Builder.getInt8PtrTy()));
-
-<i><b>// Adding a cleanup</b></i>
-LPadInst->setCleanup(true);
-
-<i><b>// Adding a filter clause</b></i>
-std::vector<Constant*> TypeInfos;
-Constant *TypeInfo = getFilterTypeInfo();
-TypeInfos.push_back(Builder.CreateBitCast(TypeInfo, Builder.getInt8PtrTy()));
-
-ArrayType *FilterTy = ArrayType::get(Int8PtrTy, TypeInfos.size());
-LPadInst->addClause(ConstantArray::get(FilterTy, TypeInfos));
-</pre>
-</div>
-
-<p>Converting from using the <code>@llvm.eh.resume</code> intrinsic to
- the <code>resume</code> instruction is trivial. It takes the exception
- pointer and exception selector values returned by
- the <code>landingpad</code> instruction:</p>
-
-<div class="doc_code">
-<pre>
-Type *UnwindDataTy = StructType::get(Builder.getInt8PtrTy(),
- Builder.getInt32Ty(), NULL);
-Value *UnwindData = UndefValue::get(UnwindDataTy);
-Value *ExcPtr = Builder.CreateLoad(getExceptionObjSlot());
-Value *ExcSel = Builder.CreateLoad(getExceptionSelSlot());
-UnwindData = Builder.CreateInsertValue(UnwindData, ExcPtr, 0, "exc_ptr");
-UnwindData = Builder.CreateInsertValue(UnwindData, ExcSel, 1, "exc_sel");
-Builder.CreateResume(UnwindData);
-</pre>
-</div>
-
-
-
-
- -->
-
-
<!-- *********************************************************************** -->
<hr>
projects / oota-llvm.git / blobdiff