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| author | Bill Wendling <isanbard@gmail.com> | 2011-04-07 04:28:16 +0000 |
|---|---|---|
| committer | Bill Wendling <isanbard@gmail.com> | 2011-04-07 04:28:16 +0000 |
| commit | 762e194268e673272606344b39b483785b71004d (patch) | |
| tree | c3c5bd8ae8d14a11e88c946a6d9895c8b7c253fd | |
| parent | 2aba8f7f84766599496a6a542d72cc21d1d27a23 (diff) | |
| download | llvm-release_29.tar.gz | |
Update the release notes.release_29
git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_29@129054 91177308-0d34-0410-b5e6-96231b3b80d8
| -rw-r--r-- | docs/ReleaseNotes.html | 1247 |
1 files changed, 495 insertions, 752 deletions
diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html index 2f83b9447d1d..bc86bd445224 100644 --- a/docs/ReleaseNotes.html +++ b/docs/ReleaseNotes.html @@ -5,11 +5,11 @@ <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <meta encoding="utf8"> <link rel="stylesheet" href="llvm.css" type="text/css"> - <title>LLVM 2.8 Release Notes</title> + <title>LLVM 2.9 Release Notes</title> </head> <body> -<div class="doc_title">LLVM 2.8 Release Notes</div> +<h1 class="doc_title">LLVM 2.9 Release Notes</h1> <img align=right src="http://llvm.org/img/DragonSmall.png" width="136" height="136" alt="LLVM Dragon Logo"> @@ -17,8 +17,8 @@ <ol> <li><a href="#intro">Introduction</a></li> <li><a href="#subproj">Sub-project Status Update</a></li> - <li><a href="#externalproj">External Projects Using LLVM 2.8</a></li> - <li><a href="#whatsnew">What's New in LLVM 2.8?</a></li> + <li><a href="#externalproj">External Projects Using LLVM 2.9</a></li> + <li><a href="#whatsnew">What's New in LLVM 2.9?</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> @@ -29,23 +29,23 @@ </div> <!-- -<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.8 +<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.9 release.<br> You may prefer the -<a href="http://llvm.org/releases/2.7/docs/ReleaseNotes.html">LLVM 2.7 +<a href="http://llvm.org/releases/2.8/docs/ReleaseNotes.html">LLVM 2.8 Release Notes</a>.</h1> ---> + --> <!-- *********************************************************************** --> -<div class="doc_section"> +<h1> <a name="intro">Introduction</a> -</div> +</h1> <!-- *********************************************************************** --> <div class="doc_text"> <p>This document contains the release notes for the LLVM Compiler -Infrastructure, release 2.8. Here we describe the status of LLVM, including +Infrastructure, release 2.9. Here we describe the status of LLVM, including major improvements from the previous release and significant known problems. All LLVM releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM releases web site</a>.</p> @@ -62,36 +62,25 @@ current one. To see the release notes for a specific release, please see the <a href="http://llvm.org/releases/">releases page</a>.</p> </div> - - -<!-- -Almost dead code. - include/llvm/Analysis/LiveValues.h => Dan - lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8. - GEPSplitterPass ---> - -<!-- Features that need text if they're finished for 2.9: +<!-- Features that need text if they're finished for 3.1: + ARM EHABI combiner-aa? strong phi elim loop dependence analysis - TBAA CorrelatedValuePropagation + lib/Transforms/IPO/MergeFunctions.cpp => consider for 3.1. --> - <!-- Announcement, lldb, libc++ --> - - <!-- *********************************************************************** --> -<div class="doc_section"> +<h1> <a name="subproj">Sub-project Status Update</a> -</div> +</h1> <!-- *********************************************************************** --> <div class="doc_text"> <p> -The LLVM 2.8 distribution currently consists of code from the core LLVM +The LLVM 2.9 distribution currently consists of code from the core LLVM repository (which roughly includes the LLVM optimizers, code generators and supporting tools), the Clang repository and the llvm-gcc repository. In addition to this code, the LLVM Project includes other sub-projects that are in @@ -102,9 +91,9 @@ development. Here we include updates on these subprojects. <!--=========================================================================--> -<div class="doc_subsection"> +<h2> <a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a> -</div> +</h2> <div class="doc_text"> @@ -115,110 +104,61 @@ standards, fast compilation, and low memory use. Like LLVM, Clang provides a modular, library-based architecture that makes it suitable for creating or integrating with other development tools. Clang is considered a production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86 -(32- and 64-bit), and for darwin-arm targets.</p> - -<p>In the LLVM 2.8 time-frame, the Clang team has made many improvements:</p> - - <ul> - <li>Clang C++ is now feature-complete with respect to the ISO C++ 1998 and 2003 standards.</li> - <li>Added support for Objective-C++.</li> - <li>Clang now uses LLVM-MC to directly generate object code and to parse inline assembly (on Darwin).</li> - <li>Introduced many new warnings, including <code>-Wmissing-field-initializers</code>, <code>-Wshadow</code>, <code>-Wno-protocol</code>, <code>-Wtautological-compare</code>, <code>-Wstrict-selector-match</code>, <code>-Wcast-align</code>, <code>-Wunused</code> improvements, and greatly improved format-string checking.</li> - <li>Introduced the "libclang" library, a C interface to Clang intended to support IDE clients.</li> - <li>Added support for <code>#pragma GCC visibility</code>, <code>#pragma align</code>, and others.</li> - <li>Added support for SSE, AVX, ARM NEON, and AltiVec.</li> - <li>Improved support for many Microsoft extensions.</li> - <li>Implemented support for blocks in C++.</li> - <li>Implemented precompiled headers for C++.</li> - <li>Improved abstract syntax trees to retain more accurate source information.</li> - <li>Added driver support for handling LLVM IR and bitcode files directly.</li> - <li>Major improvements to compiler correctness for exception handling.</li> - <li>Improved generated code quality in some areas: - <ul> - <li>Good code generation for X86-32 and X86-64 ABI handling.</li> - <li>Improved code generation for bit-fields, although important work remains.</li> - </ul> - </li> - </ul> -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="clangsa">Clang Static Analyzer</a> -</div> - -<div class="doc_text"> - -<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a> - project is an effort to use static source code analysis techniques to - automatically find bugs in C and Objective-C programs (and hopefully <a - href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the - future</a>!). The tool is very good at finding bugs that occur on specific - paths through code, such as on error conditions.</p> - -<p>The LLVM 2.8 release fixes a number of bugs and slightly improves precision - over 2.7, but there are no major new features in the release. +(32- and 64-bit), and for darwin/arm targets.</p> + +<p>In the LLVM 2.9 time-frame, the Clang team has made many improvements in C, +C++ and Objective-C support. C++ support is now generally rock solid, has +been exercised on a broad variety of code, and has several new <a +href="http://clang.llvm.org/cxx_status.html#cxx0x">C++'0x features</a> +implemented (such as rvalue references and variadic templates). LLVM 2.9 has +also brought in a large range of bug fixes and minor features (e.g. __label__ +support), and is much more compatible with the Linux Kernel.</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 issue. </p> +<ul> +</ul> </div> <!--=========================================================================--> -<div class="doc_subsection"> -<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</a> -</div> +<h2> +<a name="dragonegg">DragonEgg: GCC front-ends, LLVM back-end</a> +</h2> <div class="doc_text"> <p> -<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to -gcc-4.5. Unlike llvm-gcc, dragonegg in theory does not require any gcc-4.5 -modifications whatsoever (currently one small patch is needed) thanks to the -new <a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>. -DragonEgg is a gcc plugin that makes gcc-4.5 use the LLVM optimizers and code -generators instead of gcc's, just like with llvm-gcc. +<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. +Currently it requires a patched version of gcc-4.5. +The plugin can target the x86-32 and x86-64 processor families and has been +used successfully on the Darwin, FreeBSD and Linux platforms. +The Ada, C, C++ and Fortran languages work well. +The plugin is capable of compiling plenty of Obj-C, Obj-C++ and Java but it is +not known whether the compiled code actually works or not! </p> <p> -DragonEgg is still a work in progress, but it is able to compile a lot of code, -for example all of gcc, LLVM and clang. Currently Ada, C, C++ and Fortran work -well, while all other languages either don't work at all or only work poorly. -For the moment only the x86-32 and x86-64 targets are supported, and only on -linux and darwin (darwin may need additional gcc patches). -</p> - -<p> -The 2.8 release has the following notable changes: +The 2.9 release has the following notable changes: <ul> -<li>The plugin loads faster due to exporting fewer symbols.</li> -<li>Additional vector operations such as addps256 are now supported.</li> -<li>Ada global variables with no initial value are no longer zero initialized, -resulting in better optimization.</li> -<li>The '-fplugin-arg-dragonegg-enable-gcc-optzns' flag now runs all gcc -optimizers, rather than just a handful.</li> -<li>Fortran programs using common variables now link correctly.</li> -<li>GNU OMP constructs no longer crash the compiler.</li> +<li>The plugin is much more stable when compiling Fortran.</li> +<li>Inline assembly where an asm output is tied to an input of a different size +is now supported in many more cases.</li> +<li>Basic support for the __float128 type was added. It is now possible to +generate LLVM IR from programs using __float128 but code generation does not +work yet.</li> +<li>Compiling Java programs no longer systematically crashes the plugin.</li> </ul> </div> <!--=========================================================================--> -<div class="doc_subsection"> -<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a> -</div> - -<div class="doc_text"> -<p> -The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of -a Java Virtual Machine (Java VM or JVM) that uses LLVM for static and -just-in-time compilation. As of LLVM 2.8, VMKit now supports copying garbage -collectors, and can be configured to use MMTk's copy mark-sweep garbage -collector. In LLVM 2.8, the VMKit .NET VM is no longer being maintained. -</p> -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> +<h2> <a name="compiler-rt">compiler-rt: Compiler Runtime Library</a> -</div> +</h2> <div class="doc_text"> <p> @@ -231,19 +171,20 @@ function. The compiler-rt library provides highly optimized implementations of this and other low-level routines (some are 3x faster than the equivalent libgcc routines).</p> -<p> -All of the code in the compiler-rt project is available under the standard LLVM -License, a "BSD-style" license. New in LLVM 2.8, compiler_rt now supports -soft floating point (for targets that don't have a real floating point unit), -and includes an extensive testsuite for the "blocks" language feature and the -blocks runtime included in compiler_rt.</p> +<p>In the LLVM 2.9 timeframe, compiler_rt has had several minor changes for + better ARM support, and a fairly major license change. All of the code in the + compiler-rt project is now <a href="DeveloperPolicy.html#license">dual + licensed</a> under MIT and UIUC license, which allows you to use compiler-rt + in applications without the binary copyright reproduction clause. If you + prefer the LLVM/UIUC license, you are free to continue using it under that + license as well.</p> </div> <!--=========================================================================--> -<div class="doc_subsection"> +<h2> <a name="lldb">LLDB: Low Level Debugger</a> -</div> +</h2> <div class="doc_text"> <p> @@ -254,18 +195,18 @@ libraries in the larger LLVM Project, such as the Clang expression parser, the LLVM disassembler and the LLVM JIT.</p> <p> -LLDB is in early development and not included as part of the LLVM 2.8 release, -but is mature enough to support basic debugging scenarios on Mac OS X in C, -Objective-C and C++. We'd really like help extending and expanding LLDB to -support new platforms, new languages, new architectures, and new features. -</p> +LLDB is has advanced by leaps and bounds in the 2.9 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> </div> <!--=========================================================================--> -<div class="doc_subsection"> +<h2> <a name="libc++">libc++: C++ Standard Library</a> -</div> +</h2> <div class="doc_text"> <p> @@ -275,19 +216,54 @@ ground up to specifically target the forthcoming C++'0X standard and focus on delivering great performance.</p> <p> -As of the LLVM 2.8 release, libc++ is virtually feature complete, but would -benefit from more testing and better integration with Clang++. It is also -looking forward to the C++ committee finalizing the C++'0x standard. +In the LLVM 2.9 timeframe, libc++ has had numerous bugs fixed, and is now being +co-developed with Clang's C++'0x mode.</p> + +<p> +Like compiler_rt, libc++ is now <a href="DeveloperPolicy.html#license">dual + licensed</a> under the MIT and UIUC license, allowing it to be used more + permissively. </p> </div> +<!--=========================================================================--> +<h2> +<a name="LLBrowse">LLBrowse: IR Browser</a> +</h2> + +<div class="doc_text"> +<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> <!--=========================================================================--> -<div class="doc_subsection"> -<a name="klee">KLEE: A Symbolic Execution Virtual Machine</a> +<h2> +<a name="vmkit">VMKit</a> +</h2> + +<div class="doc_text"> +<p>The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation + of a Java Virtual Machine (Java VM or JVM) that uses LLVM for static and + just-in-time compilation. As of LLVM 2.9, VMKit now supports generational + garbage collectors. The garbage collectors are provided by the MMTk framework, + and VMKit can be configured to use one of the numerous implemented collectors + of MMTk. +</p> </div> + + +<!--=========================================================================--> +<!-- +<h2> +<a name="klee">KLEE: A Symbolic Execution Virtual Machine</a> +</h2> <div class="doc_text"> <p> @@ -298,171 +274,145 @@ states. This allows it to construct testcases that lead to faults and can even be used to verify some algorithms. </p> -<p>Although KLEE does not have any major new features as of 2.8, we have made -various minor improvements, particular to ease development:</p> -<ul> - <li>Added support for LLVM 2.8. KLEE currently maintains compatibility with - LLVM 2.6, 2.7, and 2.8.</li> - <li>Added a buildbot for 2.6, 2.7, and trunk. A 2.8 buildbot will be coming - soon following release.</li> - <li>Fixed many C++ code issues to allow building with Clang++. Mostly - complete, except for the version of MiniSAT which is inside the KLEE STP - version.</li> - <li>Improved support for building with separate source and build - directories.</li> - <li>Added support for "long double" on x86.</li> - <li>Initial work on KLEE support for using 'lit' test runner instead of - DejaGNU.</li> - <li>Added <tt>configure</tt> support for using an external version of - STP.</li> -</ul> - -</div> +<p>UPDATE!</p> +</div>--> <!-- *********************************************************************** --> -<div class="doc_section"> - <a name="externalproj">External Open Source Projects Using LLVM 2.8</a> -</div> +<h1> + <a name="externalproj">External Open Source Projects Using LLVM 2.9</a> +</h1> <!-- *********************************************************************** --> <div class="doc_text"> <p>An exciting aspect of LLVM is that it is used as an enabling technology for a lot of other language and tools projects. This section lists some of the - projects that have already been updated to work with LLVM 2.8.</p> + projects that have already been updated to work with LLVM 2.9.</p> </div> + <!--=========================================================================--> -<div class="doc_subsection"> -<a name="tce">TTA-based Codesign Environment (TCE)</a> -</div> +<h2>Crack Programming Language</h2> <div class="doc_text"> <p> -<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing -application-specific processors (ASP) based on the Transport triggered -architecture (TTA). The toolset provides a complete co-design flow from C/C++ -programs down to synthesizable VHDL and parallel program binaries. Processor -customization points include the register files, function units, supported -operations, and the interconnection network.</p> - -<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target -independent optimizations and also for parts of code generation. It generates -new LLVM-based code generators "on the fly" for the designed TTA processors and -loads them in to the compiler backend as runtime libraries to avoid per-target -recompilation of larger parts of the compiler chain.</p> - +<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> - + + <!--=========================================================================--> -<div class="doc_subsection"> -<a name="Horizon">Horizon Bytecode Compiler</a> -</div> - +<h2>TTA-based Codesign Environment (TCE)</h2> + <div class="doc_text"> -<p> -<a href="http://www.quokforge.org/projects/horizon">Horizon</a> is a bytecode -language and compiler written on top of LLVM, intended for producing -single-address-space managed code operating systems that -run faster than the equivalent multiple-address-space C systems. -More in-depth blurb is available on the <a -href="http://www.quokforge.org/projects/horizon/wiki/Wiki">wiki</a>.</p> - +<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> + + <!--=========================================================================--> -<div class="doc_subsection"> -<a name="clamav">Clam AntiVirus</a> +<h2>PinaVM</h2> + +<div class="doc_text"> +<p><a href="http://gitorious.org/pinavm/pages/Home">PinaVM</a> is an open +source, <a href="http://www.systemc.org/">SystemC</a> front-end. Unlike many +other front-ends, PinaVM actually executes the elaboration of the +program analyzed using LLVM's JIT infrastructure. It later enriches the +bitcode with SystemC-specific information.</p> </div> +<!--=========================================================================--> +<h2>Pure</h2> + <div class="doc_text"> -<p> -<a href="http://www.clamav.net">Clam AntiVirus</a> is an open source (GPL) -anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail -gateways. Since version 0.96 it has <a -href="http://vrt-sourcefire.blogspot.com/2010/09/introduction-to-clamavs-low-level.html">bytecode -signatures</a> that allow writing detections for complex malware. It -uses LLVM's JIT to speed up the execution of bytecode on -X86, X86-64, PPC32/64, falling back to its own interpreter otherwise. -The git version was updated to work with LLVM 2.8. -</p> - -<p>The <a -href="http://git.clamav.net/gitweb?p=clamav-bytecode-compiler.git;a=blob_plain;f=docs/user/clambc-user.pdf"> -ClamAV bytecode compiler</a> uses Clang and LLVM to compile a C-like -language, insert runtime checks, and generate ClamAV bytecode.</p> - +<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 0.47 has been tested and is known to work with LLVM 2.9 + (and continues to work with older LLVM releases >= 2.5).</p> </div> <!--=========================================================================--> -<div class="doc_subsection"> -<a name="pure">Pure</a> -</div> +<h2 id="icedtea">IcedTea Java Virtual Machine Implementation</h2> <div class="doc_text"> <p> -<a href="http://pure-lang.googlecode.com/">Pure</a> -is an algebraic/functional -programming language based on term rewriting. Programs are collections -of equations which are used to evaluate expressions in a symbolic -fashion. Pure offers dynamic typing, eager and lazy evaluation, lexical -closures, a hygienic macro system (also based on term rewriting), -built-in list and matrix support (including list and matrix -comprehensions) and an easy-to-use C interface. The interpreter uses -LLVM as a backend to JIT-compile Pure programs to fast native code.</p> - -<p>Pure versions 0.44 and later have been tested and are known to work with -LLVM 2.8 (and continue to work with older LLVM releases >= 2.5).</p> +<a href="http://icedtea.classpath.org/wiki/Main_Page">IcedTea</a> provides a +harness to build OpenJDK using only free software build tools and to provide +replacements for the not-yet free parts of OpenJDK. One of the extensions that +IcedTea provides is a new JIT compiler named <a +href="http://icedtea.classpath.org/wiki/ZeroSharkFaq">Shark</a> which uses LLVM +to provide native code generation without introducing processor-dependent +code. +</p> +<p> OpenJDK 7 b112, IcedTea6 1.9 and IcedTea7 1.13 and later have been tested +and are known to work with LLVM 2.9 (and continue to work with older LLVM +releases >= 2.6 as well).</p> </div> <!--=========================================================================--> -<div class="doc_subsection"> -<a name="GHC">Glasgow Haskell Compiler (GHC)</a> -</div> - +<h2>Glasgow Haskell Compiler (GHC)</h2> + <div class="doc_text"> -<p> -<a href="http://www.haskell.org/ghc/">GHC</a> is an open source, -state-of-the-art programming suite for -Haskell, a standard lazy functional programming language. It includes -an optimizing static compiler generating good code for a variety of +<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>In addition to the existing C and native code generators, GHC 7.0 now -supports an <a -href="http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/Backends/LLVM">LLVM -code generator</a>. GHC supports LLVM 2.7 and later.</p> - +supports an LLVM code generator. GHC supports LLVM 2.7 and later.</p> </div> <!--=========================================================================--> -<div class="doc_subsection"> -<a name="Clay">Clay Programming Language</a> -</div> - +<h2>Polly - Polyhedral optimizations for LLVM</h2> + <div class="doc_text"> -<p> -<a href="http://tachyon.in/clay/">Clay</a> is a new systems programming -language that is specifically designed for generic programming. It makes -generic programming very concise thanks to whole program type propagation. It -uses LLVM as its backend.</p> - +<p>Polly is a project that aims to provide advanced memory access optimizations +to better take advantage of SIMD units, cache hierarchies, multiple cores or +even vector accelerators for LLVM. Built around an abstract mathematical +description based on Z-polyhedra, it provides the infrastructure to develop +advanced optimizations in LLVM and to connect complex external optimizers. In +its first year of existence Polly already provides an exact value-based +dependency analysis as well as basic SIMD and OpenMP code generation support. +Furthermore, Polly can use PoCC(Pluto) an advanced optimizer for data-locality +and parallelism.</p> </div> <!--=========================================================================--> -<div class="doc_subsection"> -<a name="llvm-py">llvm-py Python Bindings for LLVM</a> -</div> +<h2>Rubinius</h2> <div class="doc_text"> -<p> -<a href="http://www.mdevan.org/llvm-py/">llvm-py</a> has been updated to work -with LLVM 2.8. llvm-py provides Python bindings for LLVM, allowing you to write a -compiler backend or a VM in Python.</p> - + <p><a href="http://github.com/evanphx/rubinius">Rubinius</a> is an environment + for running Ruby code which strives to write as much of the implementation in + Ruby as possible. Combined with a bytecode interpreting VM, it uses LLVM to + optimize and compile ruby code down to machine code. Techniques such as type + feedback, method inlining, and deoptimization are all used to remove dynamism + from ruby execution and increase performance.</p> </div> @@ -477,118 +427,14 @@ compiler backend or a VM in Python.</p> audio signal processing. The name FAUST stands for Functional AUdio STream. Its programming model combines two approaches: functional programming and block diagram composition. In addition with the C, C++, JAVA output formats, the -Faust compiler can now generate LLVM bitcode, and works with LLVM 2.7 and -2.8.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="jade">Jade Just-in-time Adaptive Decoder Engine</a> -</div> - -<div class="doc_text"> -<p><a -href="http://sourceforge.net/apps/trac/orcc/wiki/JadeDocumentation">Jade</a> -(Just-in-time Adaptive Decoder Engine) is a generic video decoder engine using -LLVM for just-in-time compilation of video decoder configurations. Those -configurations are designed by MPEG Reconfigurable Video Coding (RVC) committee. -MPEG RVC standard is built on a stream-based dataflow representation of -decoders. It is composed of a standard library of coding tools written in -RVC-CAL language and a dataflow configuration — block diagram — -of a decoder.</p> - -<p>Jade project is hosted as part of the <a href="http://orcc.sf.net">Open -RVC-CAL Compiler</a> and requires it to translate the RVC-CAL standard library -of video coding tools into an LLVM assembly code.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="neko_llvm_jit">LLVM JIT for Neko VM</a> -</div> - -<div class="doc_text"> -<p><a href="http://github.com/vava/neko_llvm_jit">Neko LLVM JIT</a> -replaces the standard Neko JIT with an LLVM-based implementation. While not -fully complete, it is already providing a 1.5x speedup on 64-bit systems. -Neko LLVM JIT requires LLVM 2.8 or later.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="crack">Crack Scripting Language</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://code.google.com/p/crack-language/">Crack</a> aims to provide -the ease of development of a scripting language with the performance of a -compiled language. The language derives concepts from C++, Java and Python, -incorporating object-oriented programming, operator overloading and strong -typing. Crack 0.2 works with LLVM 2.7, and the forthcoming Crack 0.2.1 release -builds on LLVM 2.8.</p> +Faust compiler can now generate LLVM bitcode, and works with LLVM 2.7-2.9.</p> </div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="DresdenTM">Dresden TM Compiler (DTMC)</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://tm.inf.tu-dresden.de">DTMC</a> provides support for -Transactional Memory, which is an easy-to-use and efficient way to synchronize -accesses to shared memory. Transactions can contain normal C/C++ code (e.g., -<code>__transaction { list.remove(x); x.refCount--; }</code>) and will be executed -virtually atomically and isolated from other transactions.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="Kai">Kai Programming Language</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://www.oriontransfer.co.nz/research/kai">Kai</a> (Japanese 会 for -meeting/gathering) is an experimental interpreter that provides a highly -extensible runtime environment and explicit control over the compilation -process. Programs are defined using nested symbolic expressions, which are all -parsed into first-class values with minimal intrinsic semantics. Kai can -generate optimised code at run-time (using LLVM) in order to exploit the nature -of the underlying hardware and to integrate with external software libraries. -It is a unique exploration into world of dynamic code compilation, and the -interaction between high level and low level semantics.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="OSL">OSL: Open Shading Language</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://code.google.com/p/openshadinglanguage/">OSL</a> is a shading -language designed for use in physically based renderers and in particular -production rendering. By using LLVM instead of the interpreter, it was able to -meet its performance goals (>= C-code) while retaining the benefits of -runtime specialization and a portable high-level language. -</p> - -</div> - - - + <!-- *********************************************************************** --> -<div class="doc_section"> - <a name="whatsnew">What's New in LLVM 2.8?</a> -</div> +<h1> + <a name="whatsnew">What's New in LLVM 2.9?</a> +</h1> <!-- *********************************************************************** --> <div class="doc_text"> @@ -601,60 +447,66 @@ in this section. </div> <!--=========================================================================--> -<div class="doc_subsection"> +<h2> <a name="majorfeatures">Major New Features</a> -</div> +</h2> <div class="doc_text"> -<p>LLVM 2.8 includes several major new capabilities:</p> +<p>LLVM 2.9 includes several major new capabilities:</p> <ul> -<li>As mentioned above, <a href="#libc++">libc++</a> and <a - href="#lldb">LLDB</a> are major new additions to the LLVM collective.</li> -<li>LLVM 2.8 now has pretty decent support for debugging optimized code. You - should be able to reliably get debug info for function arguments, assuming - that the value is actually available where you have stopped.</li> -<li>A new 'llvm-diff' tool is available that does a semantic diff of .ll - files.</li> -<li>The <a href="#mc">MC subproject</a> has made major progress in this release. - Direct .o file writing support for darwin/x86[-64] is now reliable and - support for other targets and object file formats are in progress.</li> -</ul> + +<li>Type Based Alias Analysis (TBAA) is now implemented and turned on by default + in Clang. This allows substantially better load/store optimization in some + cases. TBAA can be disabled by passing -fno-strict-aliasing. +</li> + +<li>This release has seen a continued focus on quality of debug information. + LLVM now generates much higher fidelity debug information, particularly when + debugging optimized code.</li> + +<li>Inline assembly now supports multiple alternative constraints.</li> +<li>A new backend for the NVIDIA PTX virtual ISA (used to target its GPUs) is + under rapid development. It is not generally useful in 2.9, but is making + rapid progress.</li> + +</ul> + </div> <!--=========================================================================--> -<div class="doc_subsection"> +<h2> <a name="coreimprovements">LLVM IR and Core Improvements</a> -</div> +</h2> <div class="doc_text"> <p>LLVM IR has several new features for better support of new targets and that expose new optimization opportunities:</p> <ul> -<li>The <a href="LangRef.html#int_libc">memcpy, memmove, and memset</a> - intrinsics now take address space qualified pointers and a bit to indicate - whether the transfer is "<a href="LangRef.html#volatile">volatile</a>" or not. -</li> -<li>Per-instruction debug info metadata is much faster and uses less memory by - using the new DebugLoc class.</li> -<li>LLVM IR now has a more formalized concept of "<a - href="LangRef.html#trapvalues">trap values</a>", which allow the optimizer - to optimize more aggressively in the presence of undefined behavior, while - still producing predictable results.</li> -<li>LLVM IR now supports two new <a href="LangRef.html#linkage">linkage - types</a> (linker_private_weak and linker_private_weak_def_auto) which map - onto some obscure MachO concepts.</li> +<li>The <a href="LangRef.html#bitwiseops">udiv, ashr, lshr, and shl</a> + instructions now have support exact and nuw/nsw bits to indicate that they + don't overflow or shift out bits. This is useful for optimization of <a + href="http://llvm.org/PR8862">pointer differences</a> and other cases.</li> + +<li>LLVM IR now supports the <a href="LangRef.html#globalvars">unnamed_addr</a> + attribute to indicate that constant global variables with identical + initializers can be merged. This fixed <a href="http://llvm.org/PR8927">an + issue</a> where LLVM would incorrectly merge two globals which were supposed + to have distinct addresses.</li> + +<li>The new <a href="LangRef.html#fnattrs">hotpatch attribute</a> has been added + to allow runtime patching of functions.</li> </ul> </div> <!--=========================================================================--> -<div class="doc_subsection"> +<h2> <a name="optimizer">Optimizer Improvements</a> -</div> +</h2> <div class="doc_text"> @@ -662,45 +514,67 @@ expose new optimization opportunities:</p> release includes a few major enhancements and additions to the optimizers:</p> <ul> -<li>As mentioned above, the optimizer now has support for updating debug - information as it goes. A key aspect of this is the new <a - href="SourceLevelDebugging.html#format_common_value">llvm.dbg.value</a> - intrinsic. This intrinsic represents debug info for variables that are - promoted to SSA values (typically by mem2reg or the -scalarrepl passes).</li> - -<li>The JumpThreading pass is now much more aggressive about implied value - relations, allowing it to thread conditions like "a == 4" when a is known to - be 13 in one of the predecessors of a block. It does this in conjunction - with the new LazyValueInfo analysis pass.</li> -<li>The new RegionInfo analysis pass identifies single-entry single-exit regions - in the CFG. You can play with it with the "opt -regions -analyze" or - "opt -view-regions" commands.</li> -<li>The loop optimizer has significantly improved strength reduction and analysis - capabilities. Notably it is able to build on the trap value and signed - integer overflow information to optimize <= and >= loops.</li> -<li>The CallGraphSCCPassManager now has some basic support for iterating within - an SCC when a optimizer devirtualizes a function call. This allows inlining - through indirect call sites that are devirtualized by store-load forwarding - and other optimizations.</li> -<li>The new <A href="Passes.html#loweratomic">-loweratomic</a> pass is available - to lower atomic instructions into their non-atomic form. This can be useful - to optimize generic code that expects to run in a single-threaded - environment.</li> -</ul> +<li>Link Time Optimization (LTO) has been improved to use MC for parsing inline + assembly and now can build large programs like Firefox 4 on both Mac OS X and + Linux.</li> + +<li>The new -loop-idiom pass recognizes memset/memcpy loops (and memset_pattern + on darwin), turning them into library calls, which are typically better + optimized than inline code. If you are building a libc and notice that your + memcpy and memset functions are compiled into infinite recursion, please build + with -ffreestanding or -fno-builtin to disable this pass.</li> + +<li>A new -early-cse pass does a fast pass over functions to fold constants, + simplify expressions, perform simple dead store elimination, and perform + common subexpression elimination. It does a good job at catching some of the + trivial redundancies that exist in unoptimized code, making later passes more + effective.</li> + +<li>A new -loop-instsimplify pass is used to clean up loop bodies in the loop + optimizer.</li> + +<li>The new TargetLibraryInfo interface allows mid-level optimizations to know + whether the current target's runtime library has certain functions. For + example, the optimizer can now transform integer-only printf calls to call + iprintf, allowing reduced code size for embedded C libraries (e.g. newlib). +</li> + +<li>LLVM has a new <a href="WritingAnLLVMPass.html#RegionPass">RegionPass</a> + infrastructure for region-based optimizations.</li> + +<li>Several optimizer passes have been substantially sped up: + GVN is much faster on functions with deep dominator trees and lots of basic + blocks. The dominator tree and dominance frontier passes are much faster to + compute, and preserved by more passes (so they are computed less often). The + -scalar-repl pass is also much faster and doesn't use DominanceFrontier. +</li> -<!-- -<p>In addition to these features that are done in 2.8, there is preliminary - support in the release for Type Based Alias Analysis - Preliminary work on TBAA but not usable in 2.8. - New CorrelatedValuePropagation pass, not on by default in 2.8 yet. ---> +<li>The Dead Store Elimination pass is more aggressive optimizing stores of + different types: e.g. a large store following a small one to the same address. + The MemCpyOptimizer pass handles several new forms of memcpy elimination.</li> + +<li>LLVM now optimizes various idioms for overflow detection into check of the + flag register on various CPUs. For example, we now compile: + + <pre> + unsigned long t = a+b; + if (t < a) ... + </pre> + into: + <pre> + addq %rdi, %rbx + jno LBB0_2 + </pre> +</li> + +</ul> </div> <!--=========================================================================--> -<div class="doc_subsection"> +<h2> <a name="mc">MC Level Improvements</a> -</div> +</h2> <div class="doc_text"> <p> @@ -709,26 +583,39 @@ of problems in the realm of assembly, disassembly, object file format handling, and a number of other related areas that CPU instruction-set level tools work in.</p> -<p>The MC subproject has made great leaps in LLVM 2.8. For example, support for - directly writing .o files from LLC (and clang) now works reliably for - darwin/x86[-64] (including inline assembly support) and the integrated - assembler is turned on by default in Clang for these targets. This provides - improved compile times among other things.</p> - <ul> -<li>The entire compiler has converted over to using the MCStreamer assembler API - instead of writing out a .s file textually.</li> -<li>The "assembler parser" is far more mature than in 2.7, supporting a full - complement of directives, now supports assembler macros, etc.</li> -<li>The "assembler backend" has been completed, including support for relaxation - relocation processing and all the other things that an assembler does.</li> -<li>The MachO file format support is now fully functional and works.</li> -<li>The MC disassembler now fully supports ARM and Thumb. ARM assembler support - is still in early development though.</li> -<li>The X86 MC assembler now supports the X86 AES and AVX instruction set.</li> -<li>Work on ELF and COFF object files and ARM target support is well underway, - but isn't useful yet in LLVM 2.8. Please contact the llvmdev mailing list - if you're interested in this.</li> +<li>ELF MC support has matured enough for the integrated assembler to be turned + on by default in Clang on X86-32 and X86-64 ELF systems.</li> + +<li>MC supports and CodeGen uses the <tt>.file</tt> and <tt>.loc</tt> directives + for producing line number debug info. This produces more compact line + tables and easier to read .s files.</li> + +<li>MC supports the <tt>.cfi_*</tt> directives for producing DWARF + frame information, but it is still not used by CodeGen by default.</li> + + +<li>The MC assembler now generates much better diagnostics for common errors, + is much faster at matching instructions, is much more bug-compatible with + the GAS assembler, and is now generally useful for a broad range of X86 + assembly.</li> + +<li>We now have some basic <a href="CodeGenerator.html#mc">internals + documentation</a> for MC.</li> + +<li>.td files can now specify assembler aliases directly with the <a + href="CodeGenerator.html#na_instparsing">MnemonicAlias and InstAlias</a> + tblgen classes.</li> + +<li>LLVM now has an experimental format-independent object file manipulation + library (lib/Object). It supports both PE/COFF and ELF. The llvm-nm tool has + been extended to work with native object files, and the new llvm-objdump tool + supports disassembly of object files (but no relocations are displayed yet). +</li> + +<li>Win32 PE-COFF support in the MC assembler has made a lot of progress in the + 2.9 timeframe, but is still not generally useful.</li> + </ul> <p>For more information, please see the <a @@ -736,13 +623,12 @@ 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> <!--=========================================================================--> -<div class="doc_subsection"> +<h2> <a name="codegen">Target Independent Code Generator Improvements</a> -</div> +</h2> <div class="doc_text"> @@ -751,343 +637,187 @@ infrastructure, which allows us to implement more aggressive algorithms and make it run faster:</p> <ul> -<li>The clang/gcc -momit-leaf-frame-pointer argument is now supported.</li> -<li>The clang/gcc -ffunction-sections and -fdata-sections arguments are now - supported on ELF targets (like GCC).</li> -<li>The MachineCSE pass is now tuned and on by default. It eliminates common - subexpressions that are exposed when lowering to machine instructions.</li> -<li>The "local" register allocator was replaced by a new "fast" register - allocator. This new allocator (which is often used at -O0) is substantially - faster and produces better code than the old local register allocator.</li> -<li>A new LLC "-regalloc=default" option is available, which automatically - chooses a register allocator based on the -O optimization level.</li> -<li>The common code generator code was modified to promote illegal argument and - return value vectors to wider ones when possible instead of scalarizing - them. For example, <3 x float> will now pass in one SSE register - instead of 3 on X86. This generates substantially better code since the - rest of the code generator was already expecting this.</li> -<li>The code generator uses a new "COPY" machine instruction. This speeds up - the code generator and eliminates the need for targets to implement the - isMoveInstr hook. Also, the copyRegToReg hook was renamed to copyPhysReg - and simplified.</li> -<li>The code generator now has a "LocalStackSlotPass", which optimizes stack - slot access for targets (like ARM) that have limited stack displacement - addressing.</li> -<li>A new "PeepholeOptimizer" is available, which eliminates sign and zero - extends, and optimizes away compare instructions when the condition result - is available from a previous instruction.</li> -<li>Atomic operations now get legalized into simpler atomic operations if not - natively supported, easing the implementation burden on targets.</li> -<li>We have added two new bottom-up pre-allocation register pressure aware schedulers: -<ol> -<li>The hybrid scheduler schedules aggressively to minimize schedule length when registers are available and avoid overscheduling in high pressure situations.</li> -<li>The instruction-level-parallelism scheduler schedules for maximum ILP when registers are available and avoid overscheduling in high pressure situations.</li> -</ol></li> -<li>The tblgen type inference algorithm was rewritten to be more consistent and - diagnose more target bugs. If you have an out-of-tree backend, you may - find that it finds bugs in your target description. This support also - allows limited support for writing patterns for instructions that return - multiple results (e.g. a virtual register and a flag result). The - 'parallel' modifier in tblgen was removed, you should use the new support - for multiple results instead.</li> -<li>A new (experimental) "-rendermf" pass is available which renders a - MachineFunction into HTML, showing live ranges and other useful - details.</li> -<li>The new SubRegIndex tablegen class allows subregisters to be indexed - symbolically instead of numerically. If your target uses subregisters you - will need to adapt to use SubRegIndex when you upgrade to 2.8.</li> -<!-- SplitKit --> - -<li>The -fast-isel instruction selection path (used at -O0 on X86) was rewritten - to work bottom-up on basic blocks instead of top down. This makes it - slightly faster (because the MachineDCE pass is not needed any longer) and - allows it to generate better code in some cases.</li> +<li>The pre-register-allocation (preRA) instruction scheduler models register + pressure much more accurately in some cases. This allows the adoption of more + aggressive scheduling heuristics without causing spills to be generated. +</li> + +<li>LiveDebugVariables is a new pass that keeps track of debugging information + for user variables that are promoted to registers in optimized builds.</li> +<li>The scheduler now models operand latency and pipeline forwarding.</li> + +<li>A major register allocator infrastructure rewrite is underway. It is not on + by default for 2.9 and you are not advised to use it, but it has made + substantial progress in the 2.9 timeframe: + <ul> + <li>A new -regalloc=basic "basic" register allocator can be used as a simple + fallback when debugging. It uses the new infrastructure.</li> + <li>New infrastructure is in place for live range splitting. "SplitKit" can + break a live interval into smaller pieces while preserving SSA form, and + SpillPlacement can help find the best split points. This is a work in + progress so the API is changing quickly.</li> + <li>The inline spiller has learned to clean up after live range splitting. It + can hoist spills out of loops, and it can eliminate redundant spills.</li> + <li>Rematerialization works with live range splitting.</li> + <li>The new "greedy" register allocator using live range splitting. This will + be the default register allocator in the next LLVM release, but it is not + turned on by default in 2.9.</li> + </ul> +</li> </ul> </div> <!--=========================================================================--> -<div class="doc_subsection"> +<h2> <a name="x86">X86-32 and X86-64 Target Improvements</a> -</div> +</h2> <div class="doc_text"> <p>New features and major changes in the X86 target include: </p> <ul> -<li>The X86 backend now supports holding X87 floating point stack values - in registers across basic blocks, dramatically improving performance of code - that uses long double, and when targeting CPUs that don't support SSE.</li> - -<li>The X86 backend now uses a SSEDomainFix pass to optimize SSE operations. On - Nehalem ("Core i7") and newer CPUs there is a 2 cycle latency penalty on - using a register in a different domain than where it was defined. This pass - optimizes away these stalls.</li> - -<li>The X86 backend now promotes 16-bit integer operations to 32-bits when - possible. This avoids 0x66 prefixes, which are slow on some - microarchitectures and bloat the code on all of them.</li> - -<li>The X86 backend now supports the Microsoft "thiscall" calling convention, - and a <a href="LangRef.html#callingconv">calling convention</a> to support - <a href="#GHC">ghc</a>.</li> - -<li>The X86 backend supports a new "llvm.x86.int" intrinsic, which maps onto - the X86 "int $42" and "int3" instructions.</li> - -<li>At the IR level, the <2 x float> datatype is now promoted and passed - around as a <4 x float> instead of being passed and returned as an MMX - vector. If you have a frontend that uses this, please pass and return a - <2 x i32> instead (using bitcasts).</li> - -<li>When printing .s files in verbose assembly mode (the default for clang -S), - the X86 backend now decodes X86 shuffle instructions and prints human - readable comments after the most inscrutable of them, e.g.: - -<pre> - insertps $113, %xmm3, %xmm0 <i># xmm0 = zero,xmm0[1,2],xmm3[1]</i> - unpcklps %xmm1, %xmm0 <i># xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1]</i> - pshufd $1, %xmm1, %xmm1 <i># xmm1 = xmm1[1,0,0,0]</i> -</pre> +<li>LLVM 2.9 includes a complete reimplementation of the MMX instruction set. + The reimplementation uses a new LLVM IR <a + href="LangRef.html#t_x86mmx">x86_mmx</a> type to ensure that MMX operations + are <em>only</em> generated from source that uses MMX builtin operations. With + this, random types like <2 x i32> are not turned into MMX operations + (which can be catastrophic without proper "emms" insertion). Because the X86 + code generator always generates reliable code, the -disable-mmx flag is now + removed. +</li> + +<li>X86 support for FS/GS relative loads and stores using <a + href="CodeGenerator.html#x86_memory">address space 256/257</a> works reliably + now.</li> + +<li>LLVM 2.9 generates much better code in several cases by using adc/sbb to + avoid generation of conditional move instructions for conditional increment + and other idioms.</li> + +<li>The X86 backend has adopted a new preRA scheduling mode, "list-ilp", to + shorten the height of instruction schedules without inducing register spills. </li> - + +<li>The MC assembler supports 3dNow! and 3DNowA instructions.</li> + +<li>Several bugs have been fixed for Windows x64 code generator.</li> </ul> </div> <!--=========================================================================--> -<div class="doc_subsection"> +<h2> <a name="ARM">ARM Target Improvements</a> -</div> +</h2> <div class="doc_text"> <p>New features of the ARM target include: </p> <ul> -<li>The ARM backend now optimizes tail calls into jumps.</li> -<li>Scheduling is improved through the new list-hybrid scheduler as well - as through better modeling of structural hazards.</li> -<li><a href="LangRef.html#int_fp16">Half float</a> instructions are now - supported.</li> -<li>NEON support has been improved to model instructions which operate onto - multiple consecutive registers more aggressively. This avoids lots of - extraneous register copies.</li> -<li>The ARM backend now uses a new "ARMGlobalMerge" pass, which merges several - global variables into one, saving extra address computation (all the global - variables can be accessed via same base address) and potentially reducing - register pressure.</li> - -<li>The ARM backend has received many minor improvements and tweaks which lead - to substantially better performance in a wide range of different scenarios. -</li> +<li>The ARM backend now has a fast instruction selector, which dramatically + improves -O0 compile times.</li> +<li>The ARM backend has new tuning for Cortex-A8 and Cortex-A9 CPUs.</li> +<li>The __builtin_prefetch builtin (and llvm.prefetch intrinsic) is compiled + into prefetch instructions instead of being discarded.</li> -<li>The ARM NEON intrinsics have been substantially reworked to reduce - redundancy and improve code generation. Some of the major changes are: - <ol> - <li> - All of the NEON load and store intrinsics (llvm.arm.neon.vld* and - llvm.arm.neon.vst*) take an extra parameter to specify the alignment in bytes - of the memory being accessed. - </li> - <li> - The llvm.arm.neon.vaba intrinsic (vector absolute difference and - accumulate) has been removed. This operation is now represented using - the llvm.arm.neon.vabd intrinsic (vector absolute difference) followed by a - vector add. - </li> - <li> - The llvm.arm.neon.vabdl and llvm.arm.neon.vabal intrinsics (lengthening - vector absolute difference with and without accumulation) have been removed. - They are represented using the llvm.arm.neon.vabd intrinsic (vector absolute - difference) followed by a vector zero-extend operation, and for vabal, - a vector add. - </li> - <li> - The llvm.arm.neon.vmovn intrinsic has been removed. Calls of this intrinsic - are now replaced by vector truncate operations. - </li> - <li> - The llvm.arm.neon.vmovls and llvm.arm.neon.vmovlu intrinsics have been - removed. They are now represented as vector sign-extend (vmovls) and - zero-extend (vmovlu) operations. - </li> - <li> - The llvm.arm.neon.vaddl*, llvm.arm.neon.vaddw*, llvm.arm.neon.vsubl*, and - llvm.arm.neon.vsubw* intrinsics (lengthening vector add and subtract) have - been removed. They are replaced by vector add and vector subtract operations - where one (vaddw, vsubw) or both (vaddl, vsubl) of the operands are either - sign-extended or zero-extended. - </li> - <li> - The llvm.arm.neon.vmulls, llvm.arm.neon.vmullu, llvm.arm.neon.vmlal*, and - llvm.arm.neon.vmlsl* intrinsics (lengthening vector multiply with and without - accumulation and subtraction) have been removed. These operations are now - represented as vector multiplications where the operands are either - sign-extended or zero-extended, followed by a vector add for vmlal or a - vector subtract for vmlsl. Note that the polynomial vector multiply - intrinsic, llvm.arm.neon.vmullp, remains unchanged. - </li> - </ol> -</li> +<li> The ARM backend preRA scheduler now models machine resources at cycle + granularity. This allows the scheduler to both accurately model + instruction latency and avoid overcommitting functional units.</li> +<li>Countless ARM microoptimizations have landed in LLVM 2.9.</li> </ul> </div> + +<!--=========================================================================--> +<h2> +<a name="OtherTS">Other Target Specific Improvements</a> +</h2> + +<div class="doc_text"> +<ul> +<li>MicroBlaze: major updates for aggressive delay slot filler, MC-based + assembly printing, assembly instruction parsing, ELF .o file emission, and MC + instruction disassembler have landed.</li> +<li>SPARC: Many improvements, including using the Y registers for + multiplications and addition of a simple delay slot filler.</li> + +<li>PowerPC: The backend has been largely MC'ized and is ready to support + directly writing out mach-o object files. No one seems interested in finishing + this final step though.</li> + +</ul> +</div> <!--=========================================================================--> -<div class="doc_subsection"> +<h2> <a name="changes">Major Changes and Removed Features</a> -</div> +</h2> <div class="doc_text"> <p>If you're already an LLVM user or developer with out-of-tree changes based -on LLVM 2.7, this section lists some "gotchas" that you may run into upgrading +on LLVM 2.8, this section lists some "gotchas" that you may run into upgrading from the previous release.</p> <ul> -<li>The build configuration machinery changed the output directory names. It - wasn't clear to many people that a "Release-Asserts" build was a release build - without asserts. To make this more clear, "Release" does not include - assertions and "Release+Asserts" does (likewise, "Debug" and - "Debug+Asserts").</li> -<li>The MSIL Backend was removed, it was unsupported and broken.</li> -<li>The ABCD, SSI, and SCCVN passes were removed. These were not fully - functional and their behavior has been or will be subsumed by the - LazyValueInfo pass.</li> -<li>The LLVM IR 'Union' feature was removed. While this is a desirable feature - for LLVM IR to support, the existing implementation was half baked and - barely useful. We'd really like anyone interested to resurrect the work and - finish it for a future release.</li> -<li>If you're used to reading .ll files, you'll probably notice that .ll file - dumps don't produce #uses comments anymore. To get them, run a .bc file - through "llvm-dis --show-annotations".</li> -<li>Target triples are now stored in a normalized form, and all inputs from - humans are expected to be normalized by Triple::normalize before being - stored in a module triple or passed to another library.</li> -</ul> +<li><b>This is the last release to support the llvm-gcc frontend.</b></li> +<li>LLVM has a new <a href="CodingStandards.html#ll_naming">naming + convention standard</a>, though the codebase hasn't fully adopted it yet.</li> + +<li>The new DIBuilder class provides a simpler interface for front ends to + encode debug info in LLVM IR, and has replaced DIFactory.</li> +<li>LLVM IR and other tools always work on normalized target triples (which have + been run through <tt>Triple::normalize</tt>).</li> -<p>In addition, many APIs have changed in this release. Some of the major LLVM -API changes are:</p> -<ul> -<li>LLVM 2.8 changes the internal order of operands in <a - href="http://llvm.org/doxygen/classllvm_1_1InvokeInst.html"><tt>InvokeInst</tt></a> - and <a href="http://llvm.org/doxygen/classllvm_1_1CallInst.html"><tt>CallInst</tt></a>. - To be portable across releases, please use the <tt>CallSite</tt> class and the - high-level accessors, such as <tt>getCalledValue</tt> and - <tt>setUnwindDest</tt>. -</li> -<li> - You can no longer pass use_iterators directly to cast<> (and similar), - because these routines tend to perform costly dereference operations more - than once. You have to dereference the iterators yourself and pass them in. -</li> -<li> - llvm.memcpy.*, llvm.memset.*, llvm.memmove.* intrinsics take an extra - parameter now ("i1 isVolatile"), totaling 5 parameters, and the pointer - operands are now address-space qualified. - If you were creating these intrinsic calls and prototypes yourself (as opposed - to using Intrinsic::getDeclaration), you can use - UpgradeIntrinsicFunction/UpgradeIntrinsicCall to be portable across releases. -</li> -<li> - SetCurrentDebugLocation takes a DebugLoc now instead of a MDNode. - Change your code to use - SetCurrentDebugLocation(DebugLoc::getFromDILocation(...)). -</li> -<li> - The <tt>RegisterPass</tt> and <tt>RegisterAnalysisGroup</tt> templates are - considered deprecated, but continue to function in LLVM 2.8. Clients are - strongly advised to use the upcoming <tt>INITIALIZE_PASS()</tt> and - <tt>INITIALIZE_AG_PASS()</tt> macros instead. -</li> -<li> - The constructor for the Triple class no longer tries to understand odd triple - specifications. Frontends should ensure that they only pass valid triples to - LLVM. The Triple::normalize utility method has been added to help front-ends - deal with funky triples. -</li> -<li> - The signature of the <tt>GCMetadataPrinter::finishAssembly</tt> virtual - function changed: the <tt>raw_ostream</tt> and <tt>MCAsmInfo</tt> arguments - were dropped. GC plugins which compute stack maps must be updated to avoid - having the old definition overload the new signature. -</li> -<li> - The signature of <tt>MemoryBuffer::getMemBuffer</tt> changed. Unfortunately - calls intended for the old version still compile, but will not work correctly, - leading to a confusing error about an invalid header in the bitcode. -</li> - -<li> - Some APIs were renamed: - <ul> - <li>llvm_report_error -> report_fatal_error</li> - <li>llvm_install_error_handler -> install_fatal_error_handler</li> - <li>llvm::DwarfExceptionHandling -> llvm::JITExceptionHandling</li> - <li>VISIBILITY_HIDDEN -> LLVM_LIBRARY_VISIBILITY</li> - </ul> -</li> +<li>The target triple x86_64--mingw64 is obsoleted. Use x86_64--mingw32 + instead.</li> -<li> - Some public headers were renamed: - <ul> - <li><tt>llvm/Assembly/AsmAnnotationWriter.h</tt> was renamed - to <tt>llvm/Assembly/AssemblyAnnotationWriter.h</tt> - </li> - </ul> +<li>The PointerTracking pass has been removed from mainline, and moved to The + ClamAV project (its only client).</li> + +<li>The LoopIndexSplit, LiveValues, SimplifyHalfPowrLibCalls, GEPSplitter, and + PartialSpecialization passes were removed. They were unmaintained, + buggy, or deemed to be a bad idea.</li> </ul> </div> <!--=========================================================================--> -<div class="doc_subsection"> -<a name="devtree_changes">Development Infrastructure Changes</a> -</div> +<h2> +<a name="api_changes">Internal API Changes</a> +</h2> <div class="doc_text"> -<p>This section lists changes to the LLVM development infrastructure. This -mostly impacts users who actively work on LLVM or follow development on -mainline, but may also impact users who leverage the LLVM build infrastructure -or are interested in LLVM qualification.</p> +<p>In addition, many APIs have changed in this release. Some of the major + LLVM API changes are:</p> <ul> - <li>The default for <tt>make check</tt> is now to use - the <a href="http://llvm.org/cmds/lit.html">lit</a> testing tool, which is - part of LLVM itself. You can use <tt>lit</tt> directly as well, or use - the <tt>llvm-lit</tt> tool which is created as part of a Makefile or CMake - build (and knows how to find the appropriate tools). See the <tt>lit</tt> - documentation and the <a href="http://blog.llvm.org/2009/12/lit-it.html">blog - post</a>, and <a href="http://llvm.org/bugs/show_bug.cgi?id=5217">PR5217</a> - for more information.</li> - - <li>The LLVM <tt>test-suite</tt> infrastructure has a new "simple" test format - (<tt>make TEST=simple</tt>). The new format is intended to require only a - compiler and not a full set of LLVM tools. This makes it useful for testing - released compilers, for running the test suite with other compilers (for - performance comparisons), and makes sure that we are testing the compiler as - users would see it. The new format is also designed to work using reference - outputs instead of comparison to a baseline compiler, which makes it run much - faster and makes it less system dependent.</li> - - <li>Significant progress has been made on a new interface to running the - LLVM <tt>test-suite</tt> (aka the LLVM "nightly tests") using - the <a href="http://llvm.org/docs/lnt">LNT</a> infrastructure. The LNT - interface to the <tt>test-suite</tt> brings significantly improved reporting - capabilities for monitoring the correctness and generated code quality - produced by LLVM over time.</li> +<li>include/llvm/System merged into include/llvm/Support.</li> +<li>The <a href="http://llvm.org/PR5207">llvm::APInt API</a> was significantly + cleaned up.</li> + +<li>In the code generator, MVT::Flag was renamed to MVT::Glue to more accurately + describe its behavior.</li> + +<li>The system_error header from C++0x was added, and is now pervasively used to + capture and handle i/o and other errors in LLVM.</li> + +<li>The old sys::Path API has been deprecated in favor of the new PathV2 API, + which is more efficient and flexible.</li> </ul> </div> <!-- *********************************************************************** --> -<div class="doc_section"> +<h1> <a name="knownproblems">Known Problems</a> -</div> +</h1> <!-- *********************************************************************** --> <div class="doc_text"> @@ -1100,9 +830,9 @@ there isn't already one.</p> </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h2> <a name="experimental">Experimental features included with this release</a> -</div> +</h2> <div class="doc_text"> @@ -1114,18 +844,19 @@ components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p> <ul> -<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, SystemZ +<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-i386 and darwin-x86_64.</li> + other than darwin and ELF X86 systems.</li> + </ul> </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h2> <a name="x86-be">Known problems with the X86 back-end</a> -</div> +</h2> <div class="doc_text"> @@ -1134,21 +865,31 @@ href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p> all <a href="http://llvm.org/PR879">inline assembly that uses the X86 floating point stack</a>. It supports the 'f' and 't' constraints, but not 'u'.</li> - <li>Win64 code generation wasn't widely tested. Everything should work, but we - expect small issues to happen. Also, llvm-gcc cannot build the mingw64 - runtime currently due to lack of support for the 'u' inline assembly - constraint and for X87 floating point inline assembly.</li> <li>The X86-64 backend does not yet support the LLVM IR instruction <tt>va_arg</tt>. Currently, front-ends support variadic argument constructs on X86-64 by lowering them manually.</li> + <li>Windows x64 (aka Win64) code generator has a few issues. + <ul> + <li>llvm-gcc cannot build the mingw-w64 runtime currently + due to lack of support for the 'u' inline assembly + constraint and for X87 floating point inline assembly.</li> + <li>On mingw-w64, you will see unresolved symbol <tt>__chkstk</tt> + due to <a href="http://llvm.org/bugs/show_bug.cgi?id=8919">Bug 8919</a>. + It is fixed in <a href="http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20110321/118499.html">r128206</a>.</li> + <li>Miss-aligned MOVDQA might crash your program. It is due to + <a href="http://llvm.org/bugs/show_bug.cgi?id=9483">Bug 9483</a>, + lack of handling aligned internal globals.</li> + </ul> + </li> + </ul> </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h2> <a name="ppc-be">Known problems with the PowerPC back-end</a> -</div> +</h2> <div class="doc_text"> @@ -1160,9 +901,9 @@ compilation, and lacks support for debug information.</li> </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h2> <a name="arm-be">Known problems with the ARM back-end</a> -</div> +</h2> <div class="doc_text"> @@ -1177,9 +918,9 @@ results (<a href="http://llvm.org/PR1388">PR1388</a>).</li> </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h2> <a name="sparc-be">Known problems with the SPARC back-end</a> -</div> +</h2> <div class="doc_text"> @@ -1191,9 +932,9 @@ results (<a href="http://llvm.org/PR1388">PR1388</a>).</li> </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h2> <a name="mips-be">Known problems with the MIPS back-end</a> -</div> +</h2> <div class="doc_text"> @@ -1204,9 +945,9 @@ results (<a href="http://llvm.org/PR1388">PR1388</a>).</li> </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h2> <a name="alpha-be">Known problems with the Alpha back-end</a> -</div> +</h2> <div class="doc_text"> @@ -1219,9 +960,9 @@ appropriate nops inserted to ensure restartability.</li> </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h2> <a name="c-be">Known problems with the C back-end</a> -</div> +</h2> <div class="doc_text"> @@ -1242,12 +983,14 @@ Depending on it for anything serious is not advised.</p> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h2> <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a> -</div> +</h2> <div class="doc_text"> +<p><b>LLVM 2.9 will be the last release of llvm-gcc.</b></p> + <p>llvm-gcc is generally very stable for the C family of languages. The only major language feature of GCC not supported by llvm-gcc is the <tt>__builtin_apply</tt> family of builtins. However, some extensions @@ -1268,9 +1011,9 @@ consider using <a href="#dragonegg">dragonegg</a> instead.</p> </div> <!-- *********************************************************************** --> -<div class="doc_section"> +<h1> <a name="additionalinfo">Additional Information</a> -</div> +</h1> <!-- *********************************************************************** --> <div class="doc_text"> |