<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>
+ <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
- major improvements from the previous release and significant known problems.
+ 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
the <a href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
<a href="http://llvm.org/releases/">releases page</a>.</p>
</div>
-
-<!-- Features that need text if they're finished for 3.1:
- ARM EHABI
- combiner-aa?
- strong phi elim
- loop dependence analysis
- CorrelatedValuePropagation
- lib/Transforms/IPO/MergeFunctions.cpp => consider for 3.1.
- -->
-
+
+
<!-- *********************************************************************** -->
<h2>
<a name="subproj">Sub-project Status Update</a>
<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
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, 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>
+ (32- and 64-bit), and for Darwin/ARM targets.</p>
+<p>In the LLVM 3.1 time-frame, the Clang team has made many improvements:</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, including implementations of non-static data member
- initializers, alias templates, delegating constructors, the range-based
- for loop, 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>Implemented support
- for <a href="http://clang.llvm.org/docs/AutomaticReferenceCounting.html">Automatic
- Reference Counting</a> for Objective-C.</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>...</li>
</ul>
-
+ <p>For more details about the changes to Clang since the 2.9 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
compatibility</a> guide to make sure this is not intentional or a known
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>
-
- <li>GCC version 4.6 is now fully supported.</li>
+<p>The 3.1 release has the following notable changes:</p>
- <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>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 not yet completely
- stable: it may cause the plugin to crash.</li>
+ <ul>
- <li>The type and constant conversion logic has been almost entirely rewritten,
- fixing a multitude of obscure bugs.</li>
+ <li>...</li>
-<ul>
-<!--
-<li></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,</p>
+<p>....</p>
</div>
<div>
-<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>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>...</p>
</div>
licensed</a> under the MIT and UIUC license, allowing it to be used more
permissively.</p>
-</div>
-
-
-<!--=========================================================================-->
-<h3>
-<a name="LLBrowse">LLBrowse: IR Browser</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>
+<p>...</p>
</div>
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
+ <p>In the LLVM 3.1 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>
-
- <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>
+ <li>...</li>
</ul>
</div>
-
-
-<!--=========================================================================-->
-<!--
-<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>
-
-<p>UPDATE!</p>
-</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.</p>
-
-<p>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 uses LLVM's JIT and clang; it currently supports
- C++ and C. 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>
-
-<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>
-
-<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>
-
-</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>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>
-
-</div>
-
-<!--=========================================================================-->
-<h3>ispc: The Intel SPMD Program Compiler</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="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>
-
-<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>
-
-</div>
-
-<!--=========================================================================-->
-<h3>LuaAV</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>
-
-</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 with some patches. See:
- https://github.com/mono/llvm</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>
-
-</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="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>
-
-</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>TCE uses 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>
-
-<!--=========================================================================-->
-<h3>Tart Programming Language</h3>
-
-<div>
+ projects that have already been updated to work with LLVM 3.1.</p>
-<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>
+ ... to be filled in right before the release ...
</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>
<!-- *********************************************************************** -->
<div>
-<p><b>llvm-gcc is gone</b></p>
+ <!-- Features that need text if they're finished for 3.1:
+ ARM EHABI
+ combiner-aa?
+ strong phi elim
+ loop dependence analysis
+ CorrelatedValuePropagation
+ lib/Transforms/IPO/MergeFunctions.cpp => consider for 3.1.
+ Integrated assembler on by default for arm/thumb?
-<p>LLVM 3.0 includes several major new capabilities:</p>
-
-<!-- Near dead:
+ -->
+
+ <!-- Near dead:
Analysis/RegionInfo.h + Dom Frontiers
SparseBitVector: used in LiveVar.
-
- -->
-
-<!--
- Type system rewrite.
- Better performance for Neon code in clang due to SRoA improvements.
- New regalloc on by default. Lin scan going away in 3.1
- PGO / builtin_expect improvements (summary needed)
- Big EH rewrite.
- AVX support, assembler, compiler and disassembler.
- IndVar improvements: andy
- PTX backend improvements: Justin
- llvm-rtdyld & MC JIT: JimG
- InstAliases now automatically used in the asmprinter where they are shorter.
- Integrated assembler on by default for arm/thumb?
- PostOrder Dominator frontiers were removed.
- Line Profiling / gcov support
- EH and debug information produced with CFI directives, yielding smaller executables: http://blog.mozilla.com/respindola/2011/05/12/cfi-directives/
- X86-64 generates smaller and faster code at -O0 (fast isel improvements)
- Better code generation for Cortex-A9
- Many APIs take ArrayRef's now.
- Pass manager extension API.
-
-
-Information about branch probability and basic block frequency is now available within LLVM based on a combination of static branch prediction heuristics and __builtin_expect calls. That information is currently used for register spill placement and if-conversion, with additional optimizations planned for future releases. The same frameworks are intended for eventual use with profile-guided optimization, but that is not yet implemented.
-
- -->
-
-<ul>
+ llvm/lib/Archive - replace with lib object?
+ -->
+
+<p>LLVM 3.1 includes several major changes and big features:</p>
-<!--
-<li></li>
--->
-
+<ul>
+ <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>....</li>
</ul>
-
+
</div>
+
<!--=========================================================================-->
<h3>
<a name="coreimprovements">LLVM IR and Core Improvements</a>
<p>LLVM IR has several new features for better support of new targets and that
expose new optimization opportunities:</p>
-<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>
-
-</div>
-
-<!--=========================================================================-->
-<h3>
-<a name="loopoptimization">Loop Optimization Improvements</a>
-</h3>
-
-<div>
-<p>The induction variable simplification pass in 3.0 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 in a
- typically suboptimal form prior to optimization. This new design
- preserves more IR level information, avoids undoing earlier loop
- optimizations (particularly hand-optimized loops), and no longer
- strongly depends on the code generator rewriting loops a second time
- in a now optimal form--an intractable problem.</p>
-
-<p>The original behavior can be restored with -mllvm -enable-iv-rewrite;
- however, support for this mode will be short lived. As such, bug
- reports should be filed for any significant performance regressions
- when moving from -mllvm -enable-iv-rewrite to the 3.0 default mode.</p>
+ <ul>
+ <li>IR support for half float</li>
+ <li>IR support for 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.</li>
+ <li>Loads can now have range metadata attached to them to describe the
+ possible values being loaded.</li>
+ <li>....</li>
+ </ul>
</div>
<!--=========================================================================-->
<div>
-<p>In addition to a large array of minor performance tweaks and bug fixes, this
+<p>In addition to many minor performance tweaks and bug fixes, this
release includes a few major enhancements and additions to the
optimizers:</p>
<ul>
-<!--
-<li></li>
--->
-</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>....</li>
</ul>
</div>
<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>
+ in. 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>
<ul>
- <li>The ELF object streamers are much more full featured.</li>
- <li>Target dependent relocation handling has been refactored into the Targets.</li>
- <li>Early stage MC-JIT infrastructure has been implemented.</li>
+ <li>....</li>
</ul>
-<p>The MC-JIT is a major new feature for MC, and will eventually grow to replace
-the current JIT implementation. 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.</p>
-
-<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>
+<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></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>
</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>
<!--=========================================================================-->
<p>New features and major changes in the X86 target include:</p>
<ul>
-
- <li>The X86 backend now supports
- all <a href="http://llvm.org/PR879">inline assembly that uses the X86
- floating point stack</a>.</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>Bug fixes and improved support for AVX1</li>
+ <li>Support for AVX2 (still incomplete at this point)</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>
</ul>
</div>
<p>New features of the ARM target include:</p>
<ul>
- <li>Reworked Set Jump Long Jump EH Lowering,</li>
- <li>improved support for Cortex-M series processors, and</li>
- <li>beta quality integrated assembler support.</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>
+
+<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>
<div>
-<p>New features and major changes in the MIPS target include:</p>
+<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>
<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>....</li>
</ul>
</div>
-<!--=========================================================================-->
-<h3>
- <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>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>
-
-</div>
-
<!--=========================================================================-->
<h3>
<a name="OtherTS">Other Target Specific Improvements</a>
<div>
- <p>PPC32/ELF va_arg was implemented.</p>
- <p>PPC32 initial support for .o file writing was implemented.</p>
- <p>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>.</p>
-
+<p>Support for Qualcomm's Hexagon VLIW processor has been added.</p>
+
<ul>
-<!--
-<li></li>
--->
+ <li>....</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>The <code>LLVMC</code> front end code was removed while separating
- out language independence.</li>
- <li>The <code>LowerSetJmp</code> pass wasn't used effectively by any
- target and has been 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.</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 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>....</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>
-</ul>
-
-</div>
-
</div>
<!--=========================================================================-->
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>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>
-
- <li>The <code>LLVMAddLowerSetJmpPass</code> function from the C API was
- removed because the <code>LowerSetJmp</code> pass was removed.</li>
-
- <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>
-
- <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>
-
- <li>UpgradeIntrinsicCall no longer upgrades pre-2.9 intrinsic calls (for
- example <code>llvm.memset.i32</code>).</li>
-
- <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>
+ <li>....</li>
</ul>
</div>
-</div>
-
-<!-- *********************************************************************** -->
-<h2>
- <a name="knownproblems">Known Problems</a>
-</h2>
-<!-- *********************************************************************** -->
-
-<div>
-
-<p>This section contains significant known problems with the LLVM system, listed
- by component. If you run into a problem, please check
- the <a href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
- there isn't already one.</p>
-
-<!-- ======================================================================= -->
+<!--=========================================================================-->
<h3>
- <a name="experimental">Experimental features included with this release</a>
+<a name="tools_changes">Tools Changes</a>
</h3>
<div>
-<p>The following components of this LLVM release are either untested, known to
- be broken or unreliable, or are in early development. These components
- should not be relied on, and bugs should not be filed against them, but they
- may be useful to some people. In particular, if you would like to work on
- one of these components, please contact us on
- the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev
- list</a>.</p>
+<p>In addition, some tools have changed in this release. Some of the changes
+ are:</p>
-<ul>
- <li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, PTX, SystemZ and
- XCore backends are experimental.</li>
-
- <li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets other
- than darwin and ELF X86 systems.</li>
-</ul>
-
-</div>
-
-<!-- ======================================================================= -->
-<h3>
- <a name="x86-be">Known problems with the X86 back-end</a>
-</h3>
-
-<div>
<ul>
- <li>The X86-64 backend <a href="http://llvm.org/PR1740">does not yet support
- the <tt>va_arg</tt> LLVM IR instruction</a>. Currently, front-ends support
- variadic argument constructs on X86-64 by lowering them manually.</li>
+ <li>llvm-stress is a command line tool for generating random .ll files to fuzz
+ different LLVM components. </li>
+ <li>....</li>
</ul>
-</div>
-
-<!-- ======================================================================= -->
-<h3>
- <a name="ppc-be">Known problems with the PowerPC back-end</a>
-</h3>
-
-<div>
-
<ul>
- <li>The PPC32/ELF support lacks PIC support.</li>
+ <li>....</li>
</ul>
</div>
-<!-- ======================================================================= -->
-<h3>
- <a name="arm-be">Known problems with the ARM back-end</a>
-</h3>
-
-<div>
-
-<ul>
- <li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
- processors, thumb programs can crash or produce wrong results
- (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
-
- <li>Compilation for ARM Linux OABI (old ABI) is supported but not fully
- tested.</li>
-</ul>
-
-</div>
-
-<!-- ======================================================================= -->
-<h3>
- <a name="sparc-be">Known problems with the SPARC back-end</a>
-</h3>
-
-<div>
-
-<ul>
- <li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
- support the 64-bit SPARC ABI (-m64).</li>
-</ul>
-
-</div>
-
-<!-- ======================================================================= -->
-<h3>
- <a name="mips-be">Known problems with the MIPS back-end</a>
-</h3>
-
-<div>
-
-<ul>
- <li>64-bit MIPS targets are not supported yet.</li>
-</ul>
-
</div>
-<!-- ======================================================================= -->
-<h3>
- <a name="alpha-be">Known problems with the Alpha back-end</a>
-</h3>
+<!-- *********************************************************************** -->
+<h2>
+ <a name="knownproblems">Known Problems</a>
+</h2>
+<!-- *********************************************************************** -->
<div>
-<ul>
- <li>On 21164s, some rare FP arithmetic sequences which may trap do not have
- the appropriate nops inserted to ensure restartability.</li>
-</ul>
-
-</div>
-
-<!-- ======================================================================= -->
-<h3>
- <a name="c-be">Known problems with the C back-end</a>
-</h3>
-
-<div>
+<p>LLVM is generally a production quality compiler, and is used by a broad range
+ of applications and shipping in many products. That said, not every
+ subsystem is as mature as the aggregate, particularly the more obscure
+ targets. If you run into a problem, please check the <a
+ href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
+ there isn't already one or ask on the <a
+ href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev
+ list</a>.</p>
-<p>The C backend has numerous problems and is not being actively maintained.
- Depending on it for anything serious is not advised.</p>
+ <p>Known problem areas include:</p>
<ul>
- <li><a href="http://llvm.org/PR802">The C backend has only basic support for
- inline assembly code</a>.</li>
-
- <li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
- C++ programs</a>, preventing intermixing between C++ compiled by the CBE
- and C++ code compiled with <tt>llc</tt> or native compilers.</li>
-
- <li>The C backend does not support all exception handling constructs.</li>
-
- <li>The C backend does not support arbitrary precision integers.</li>
+ <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 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>
projects / oota-llvm.git / blobdiff