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1495 lines
57 KiB
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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"http://www.w3.org/TR/html4/strict.dtd">
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<html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link rel="stylesheet" href="llvm.css" type="text/css">
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<title>LLVM 3.0 Release Notes</title>
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</head>
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<body>
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<h1>LLVM 3.0 Release Notes</h1>
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<img align=right src="http://llvm.org/img/DragonSmall.png"
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width="136" height="136" alt="LLVM Dragon Logo">
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<ol>
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<li><a href="#intro">Introduction</a></li>
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<li><a href="#subproj">Sub-project Status Update</a></li>
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<li><a href="#externalproj">External Projects Using LLVM 3.0</a></li>
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<li><a href="#whatsnew">What's New in LLVM 3.0?</a></li>
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<li><a href="GettingStarted.html">Installation Instructions</a></li>
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<li><a href="#knownproblems">Known Problems</a></li>
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<li><a href="#additionalinfo">Additional Information</a></li>
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</ol>
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<div class="doc_author">
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<p>Written by the <a href="http://llvm.org/">LLVM Team</a></p>
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</div>
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<!--
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<h1 style="color:red">These are in-progress notes for the upcoming LLVM 3.0
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release.<br>
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You may prefer the
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<a href="http://llvm.org/releases/2.9/docs/ReleaseNotes.html">LLVM 2.9
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Release Notes</a>.</h1>
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-->
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<!-- *********************************************************************** -->
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<h2>
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<a name="intro">Introduction</a>
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</h2>
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<!-- *********************************************************************** -->
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<div>
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<p>This document contains the release notes for the LLVM Compiler
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Infrastructure, release 3.0. Here we describe the status of LLVM, including
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major improvements from the previous release, improvements in various
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subprojects of LLVM, and some of the current users of the code.
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All LLVM releases may be downloaded from
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the <a href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
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<p>For more information about LLVM, including information about the latest
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release, please check out the <a href="http://llvm.org/">main LLVM web
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site</a>. If you have questions or comments,
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the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM
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Developer's Mailing List</a> is a good place to send them.</p>
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<p>Note that if you are reading this file from a Subversion checkout or the main
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LLVM web page, this document applies to the <i>next</i> release, not the
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current one. To see the release notes for a specific release, please see the
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<a href="http://llvm.org/releases/">releases page</a>.</p>
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</div>
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<!-- *********************************************************************** -->
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<h2>
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<a name="subproj">Sub-project Status Update</a>
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</h2>
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<!-- *********************************************************************** -->
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<div>
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<p>The LLVM 3.0 distribution currently consists of code from the core LLVM
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repository (which roughly includes the LLVM optimizers, code generators and
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supporting tools), and the Clang repository. In
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addition to this code, the LLVM Project includes other sub-projects that are
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in development. Here we include updates on these subprojects.</p>
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<!--=========================================================================-->
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<h3>
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<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
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</h3>
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<div>
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<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
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C++, and Objective-C languages. Clang aims to provide a better user
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experience through expressive diagnostics, a high level of conformance to
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language standards, fast compilation, and low memory use. Like LLVM, Clang
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provides a modular, library-based architecture that makes it suitable for
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creating or integrating with other development tools. Clang is considered a
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production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86
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(32- and 64-bit), and for Darwin/ARM targets.</p>
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<p>In the LLVM 3.0 time-frame, the Clang team has made many improvements:</p>
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<ul>
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<li>Greatly improved support for building C++ applications, with greater
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stability and better diagnostics.</li>
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<li><a href="http://clang.llvm.org/cxx_status.html">Improved support</a> for
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the <a href="http://www.iso.org/iso/iso_catalogue/catalogue_tc/catalogue_detail.htm?csnumber=50372">C++
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2011</a> standard (aka "C++'0x"), including implementations of non-static data member
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initializers, alias templates, delegating constructors, range-based
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for loops, and implicitly-generated move constructors and move assignment
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operators, among others.</li>
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<li>Implemented support for some features of the upcoming C1x standard,
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including static assertions and generic selections.</li>
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<li>Better detection of include and linking paths for system headers and
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libraries, especially for Linux distributions.</li>
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<li>Several improvements to Objective-C support, including:
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<ul>
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<li><a href="http://clang.llvm.org/docs/AutomaticReferenceCounting.html">
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Automatic Reference Counting</a> (ARC) and an improved memory model
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cleanly separating object and C memory.</li>
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<li>A migration tool for moving manual retain/release code to ARC</li>
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<li>Better support for data hiding, allowing instance variables to be
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declared in implementation contexts or class extensions</li>
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<li>Weak linking support for Objective-C classes</li>
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<li>Improved static type checking by inferring the return type of methods
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such as +alloc and -init.</li>
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</ul>
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Some new Objective-C features require either the Mac OS X 10.7 / iOS 5
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Objective-C runtime, or version 1.6 or later of the GNUstep Objective-C
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runtime version.</li>
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<li>Implemented a number of optimizations in <tt>libclang</tt>, the Clang C
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interface, to improve the performance of code completion and the mapping
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from source locations to abstract syntax tree nodes.</li>
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</ul>
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<p>If Clang rejects your code but another compiler accepts it, please take a
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look at the <a href="http://clang.llvm.org/compatibility.html">language
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compatibility</a> guide to make sure this is not intentional or a known
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issue.</p>
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</div>
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<!--=========================================================================-->
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<h3>
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<a name="dragonegg">DragonEgg: GCC front-ends, LLVM back-end</a>
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</h3>
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<div>
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<p><a href="http://dragonegg.llvm.org/">DragonEgg</a> is a
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<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin</a> that replaces GCC's
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optimizers and code generators with LLVM's. It works with gcc-4.5 or gcc-4.6,
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targets the x86-32 and x86-64 processor families, and has been successfully
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used on the Darwin, FreeBSD, KFreeBSD, Linux and OpenBSD platforms. It fully
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supports Ada, C, C++ and Fortran. It has partial support for Go, Java, Obj-C
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and Obj-C++.</p>
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<p>The 3.0 release has the following notable changes:</p>
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<ul>
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<li>GCC version 4.6 is now fully supported.</li>
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<li>Patching and building GCC is no longer required: the plugin should work
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with your system GCC (version 4.5 or 4.6; on Debian/Ubuntu systems the
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gcc-4.5-plugin-dev or gcc-4.6-plugin-dev package is also needed).</li>
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<li>The <tt>-fplugin-arg-dragonegg-enable-gcc-optzns</tt> option, which runs
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GCC's optimizers as well as LLVM's, now works much better. This is the
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option to use if you want ultimate performance! It is still experimental
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though: it may cause the plugin to crash.</li>
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<li>The type and constant conversion logic has been almost entirely rewritten,
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fixing a multitude of obscure bugs.</li>
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</ul>
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</div>
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<!--=========================================================================-->
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<h3>
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<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
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</h3>
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<div>
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<p>The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
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is a simple library that provides an implementation of the low-level
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target-specific hooks required by code generation and other runtime
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components. For example, when compiling for a 32-bit target, converting a
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double to a 64-bit unsigned integer is compiled into a runtime call to the
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"__fixunsdfdi" function. The compiler-rt library provides highly optimized
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implementations of this and other low-level routines (some are 3x faster than
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the equivalent libgcc routines).</p>
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<p>In the LLVM 3.0 timeframe, the target specific ARM code has converted to
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"unified" assembly syntax, and several new functions have been added to the
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library.</p>
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</div>
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<!--=========================================================================-->
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<h3>
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<a name="lldb">LLDB: Low Level Debugger</a>
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</h3>
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<div>
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<p>LLDB has advanced by leaps and bounds in the 3.0 timeframe. It is
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dramatically more stable and useful, and includes both a
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new <a href="http://lldb.llvm.org/tutorial.html">tutorial</a> and
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a <a href="http://lldb.llvm.org/lldb-gdb.html">side-by-side comparison with
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GDB</a>.</p>
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</div>
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<!--=========================================================================-->
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<h3>
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<a name="libc++">libc++: C++ Standard Library</a>
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</h3>
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<div>
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<p>Like compiler_rt, libc++ is now <a href="DeveloperPolicy.html#license">dual
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licensed</a> under the MIT and UIUC license, allowing it to be used more
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permissively.</p>
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<p>Libc++ has been ported to FreeBSD and imported into the base system. It is
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planned to be the default STL implementation for FreeBSD 10.</p>
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</div>
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<!--=========================================================================-->
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<h3>
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<a name="LLBrowse">LLBrowse: IR Browser</a>
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</h3>
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<div>
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<p><a href="http://llvm.org/svn/llvm-project/llbrowse/trunk/doc/LLBrowse.html">
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LLBrowse</a> is an interactive viewer for LLVM modules. It can load any LLVM
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module and displays its contents as an expandable tree view, facilitating an
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easy way to inspect types, functions, global variables, or metadata nodes. It
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is fully cross-platform, being based on the popular wxWidgets GUI
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toolkit.</p>
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</div>
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<!--=========================================================================-->
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<h3>
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<a name="vmkit">VMKit</a>
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</h3>
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<div>
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<p>The <a href="http://vmkit.llvm.org/">VMKit project</a> is an
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implementation of a Java Virtual Machine (Java VM or JVM) that uses LLVM for
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static and just-in-time compilation.
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<p>In the LLVM 3.0 time-frame, VMKit has had significant improvements on both
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runtime and startup performance:</p>
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<ul>
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<li>Precompilation: by compiling ahead of time a small subset of Java's core
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library, the startup performance have been highly optimized to the point that
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running a 'Hello World' program takes less than 30 milliseconds.</li>
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<li>Customization: by customizing virtual methods for individual classes,
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the VM can statically determine the target of a virtual call, and decide to
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inline it.</li>
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<li>Inlining: the VM does more inlining than it did before, by allowing more
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bytecode instructions to be inlined, and thanks to customization. It also
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inlines GC barriers, and object allocations.</li>
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<li>New exception model: the generated code for a method that does not do
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any try/catch is not penalized anymore by the eventuality of calling a
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method that throws an exception. Instead, the method that throws the
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exception jumps directly to the method that could catch it.</li>
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</ul>
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</div>
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<!--=========================================================================-->
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<!--
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<h3>
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<a name="klee">KLEE: A Symbolic Execution Virtual Machine</a>
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</h3>
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<div>
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<p>
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<a href="http://klee.llvm.org/">KLEE</a> is a symbolic execution framework for
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programs in LLVM bitcode form. KLEE tries to symbolically evaluate "all" paths
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through the application and records state transitions that lead to fault
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states. This allows it to construct testcases that lead to faults and can even
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be used to verify some algorithms.
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</p>
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<p>UPDATE!</p>
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</div>-->
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</div>
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<!-- *********************************************************************** -->
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<h2>
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<a name="externalproj">External Open Source Projects Using LLVM 3.0</a>
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</h2>
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<!-- *********************************************************************** -->
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<div>
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<p>An exciting aspect of LLVM is that it is used as an enabling technology for
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a lot of other language and tools projects. This section lists some of the
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projects that have already been updated to work with LLVM 3.0.</p>
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<!--=========================================================================-->
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<h3>AddressSanitizer</h3>
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<div>
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<p><a href="http://code.google.com/p/address-sanitizer/">AddressSanitizer</a>
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uses compiler instrumentation and a specialized malloc library to find C/C++
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bugs such as use-after-free and out-of-bound accesses to heap, stack, and
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globals. The key feature of the tool is speed: the average slowdown
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introduced by AddressSanitizer is less than 2x.</p>
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</div>
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<!--=========================================================================-->
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<h3>ClamAV</h3>
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<div>
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<p><a href="http://www.clamav.net">Clam AntiVirus</a> is an open source (GPL)
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anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail
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gateways.</p>
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<p>Since version 0.96 it
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has <a href="http://vrt-sourcefire.blogspot.com/2010/09/introduction-to-clamavs-low-level.html">bytecode
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signatures</a> that allow writing detections for complex malware.</p>
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<p>It uses LLVM's JIT to speed up the execution of bytecode on X86, X86-64,
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PPC32/64, falling back to its own interpreter otherwise. The git version was
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updated to work with LLVM 3.0.</p>
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</div>
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<!--=========================================================================-->
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<h3>clang_complete for VIM</h3>
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<div>
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<p><a href="https://github.com/Rip-Rip/clang_complete">clang_complete</a> is a
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VIM plugin, that provides accurate C/C++ autocompletion using the clang front
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end. The development version of clang complete, can directly use libclang
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which can maintain a cache to speed up auto completion.</p>
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</div>
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<!--=========================================================================-->
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<h3>clReflect</h3>
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<div>
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<p><a href="https://bitbucket.org/dwilliamson/clreflect">clReflect</a> is a C++
|
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parser that uses clang/LLVM to derive a light-weight reflection database
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suitable for use in game development. It comes with a very simple runtime
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library for loading and querying the database, requiring no external
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dependencies (including CRT), and an additional utility library for object
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management and serialisation.</p>
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</div>
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<!--=========================================================================-->
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<h3>Cling C++ Interpreter</h3>
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<div>
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<p><a href="http://cern.ch/cling">Cling</a> is an interactive compiler interface
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(aka C++ interpreter). It uses LLVM's JIT and clang; it currently supports
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C++ and C. It has a prompt interface, runs source files, calls into shared
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libraries, prints the value of expressions, even does runtime lookup of
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identifiers (dynamic scopes). And it just behaves like one would expect from
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an interpreter.</p>
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</div>
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<!--=========================================================================-->
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<h3>Crack Programming Language</h3>
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<div>
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<p><a href="http://code.google.com/p/crack-language/">Crack</a> aims to provide
|
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the ease of development of a scripting language with the performance of a
|
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compiled language. The language derives concepts from C++, Java and Python,
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incorporating object-oriented programming, operator overloading and strong
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typing.</p>
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</div>
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<!--=========================================================================-->
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<h3>Eero</h3>
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<div>
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<p><a href="http://eerolanguage.org/">Eero</a> is a fully
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header-and-binary-compatible dialect of Objective-C 2.0, implemented with a
|
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patched version of the Clang/LLVM compiler. It features a streamlined syntax,
|
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Python-like indentation, and new operators, for improved readability and
|
|
reduced code clutter. It also has new features such as limited forms of
|
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operator overloading and namespaces, and strict (type-and-operator-safe)
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enumerations. It is inspired by languages such as Smalltalk, Python, and
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Ruby.</p>
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</div>
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<!--=========================================================================-->
|
|
<h3>FAUST Real-Time Audio Signal Processing Language</h3>
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<div>
|
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<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
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AUdio STream. Its programming model combines two approaches: functional
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|
programming and block diagram composition. In addition with the C, C++, Java
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|
output formats, the Faust compiler can now generate LLVM bitcode, and works
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with LLVM 2.7-3.0.
|
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</p>
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</div>
|
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|
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<!--=========================================================================-->
|
|
<h3>Glasgow Haskell Compiler (GHC)</h3>
|
|
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<div>
|
|
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<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>
|
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|
|
<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
|
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platform with LLVM 3.0.</p>
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</div>
|
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<!--=========================================================================-->
|
|
<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
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|
that should be extendable.</p>
|
|
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|
<p>gwXscript is strongly typed and offers comfort with its native types string,
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|
hash and array. You can easily write new libraries in gwXscript or native
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|
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>
|
|
|
|
<p><a href="http://code.google.com/p/tart/">Tart</a> is a general-purpose,
|
|
strongly typed programming language designed for application
|
|
developers. Strongly inspired by Python and C#, Tart focuses on practical
|
|
solutions for the professional software developer, while avoiding the clutter
|
|
and boilerplate of legacy languages like Java and C++. Although Tart is still
|
|
in development, the current implementation supports many features expected of
|
|
a modern programming language, such as garbage collection, powerful
|
|
bidirectional type inference, a greatly simplified syntax for template
|
|
metaprogramming, closures and function literals, reflection, operator
|
|
overloading, explicit mutability and immutability, and much more. Tart is
|
|
flexible enough to accommodate a broad range of programming styles and
|
|
philosophies, while maintaining a strong commitment to simplicity, minimalism
|
|
and elegance in design.</p>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<h3>ThreadSanitizer</h3>
|
|
|
|
<div>
|
|
|
|
<p><a href="http://code.google.com/p/data-race-test/">ThreadSanitizer</a> is a
|
|
data race detector for (mostly) C and C++ code, available for Linux, Mac OS
|
|
and Windows. On different systems, we use binary instrumentation frameworks
|
|
(Valgrind and Pin) as frontends that generate the program events for the race
|
|
detection algorithm. On Linux, there's an option of using LLVM-based
|
|
compile-time instrumentation.</p>
|
|
|
|
</div>
|
|
|
|
</div>
|
|
|
|
<!-- *********************************************************************** -->
|
|
<h2>
|
|
<a name="whatsnew">What's New in LLVM 3.0?</a>
|
|
</h2>
|
|
<!-- *********************************************************************** -->
|
|
|
|
<div>
|
|
|
|
<p>This release includes a huge number of bug fixes, performance tweaks and
|
|
minor improvements. Some of the major improvements and new features are
|
|
listed in this section.</p>
|
|
|
|
<!--=========================================================================-->
|
|
<h3>
|
|
<a name="majorfeatures">Major New Features</a>
|
|
</h3>
|
|
|
|
<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.
|
|
-->
|
|
|
|
<p><b>llvm-gcc is gone</b>. LLVM's configure script doesn't depend on llvm-gcc anymore, clean layering.</p>
|
|
|
|
<p>LLVM 3.0 includes several major new capabilities:</p>
|
|
|
|
<!-- Near dead:
|
|
Analysis/RegionInfo.h + Dom Frontiers
|
|
SparseBitVector: used in LiveVar.
|
|
llvm/lib/Archive - replace with lib object?
|
|
-->
|
|
|
|
<!--
|
|
Type system rewrite: http://blog.llvm.org/2011/11/llvm-30-type-system-rewrite.html
|
|
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.
|
|
ARM inline asm constraints implemented.
|
|
LangRef.html#fnattrs uwtable attribute for asynch unwind tables.
|
|
better performance for indirect gotos.
|
|
llvm.prefetch now takes a 4th argument that specifies whether the prefetch happens to the icache or dcache.
|
|
New PackedVector, TinyPtrVector class (see Programmer's Manual)
|
|
New nonlazybind function attribute.
|
|
ARC language specific optimizer (Transforms/ObjCARC) a decent example of language-specific transformation.
|
|
LLVM 3.0 removes support for reading LLVM 2.8 and earlier files. Aim to maintain compatibility all the way back to 3.0 "forever".
|
|
|
|
New llvm.expect intrinsic.
|
|
Table generated MC expansion logic for pseudo instructions that expand to multiple MC instructions through the PseudoInstExpansion class. (JimG)
|
|
New llvm.fma intrinsic.
|
|
|
|
Euro dev meeting and main one too.
|
|
New atomics instructions, "#i_fence" instruction, cmpxchg, atomicrmw too. What target support (X86/ARM)? Also 'atomic load/store'. See Atomics.html
|
|
X86: inline assembler supports .code32 and .code64.
|
|
Exception handling rewrite: new landingpad and resume instruction. Unwind gone.
|
|
LowerSetJmp pass removed, unused.
|
|
llvm-objdump / dwarf parser library / llvm-dwarfdump (d0k)
|
|
object file parsing stuff and llvm-size (mspencer)
|
|
llvm-cov (devang)
|
|
Old arm disassembler replaced with a new one based on autogenerated encoding information from ARM .td files.
|
|
Frontend tests removed from llvm/test/Frontend* (was this completed for 3.0?)
|
|
Segmented stack support (X86 only?) Rafael and Sanjoy Das: docs/SegmentedStacks.html should be in CodeGen.html status table?
|
|
X86 backend support for NaCl (David Meyer / Nick L)
|
|
Codegen now supports vector "select" operations on vector comparisons, turning
|
|
them into various optimized code sequences (e.g. using the SSE4/AVX "blend"
|
|
instructions).
|
|
#line directives in integrated assembler
|
|
SSE domain fixing code enabled for AVX (Bruno/Jakob). Domain fixing pass is
|
|
now target independent (ExecutionDepsFix pass). (Jakob)
|
|
X86 backend synthesizes horizontal add/sub instructions from generic code.
|
|
returns_twice attribute (rafael)
|
|
Tablegen has been split into a library, clang tblgen pieces now live in clang.
|
|
The llvm version is now named llvm-tblgen instead of tblgen.
|
|
X86: Tons of encoding improvements and new instructions (e.g. Atom, Ivy Bridge,
|
|
and BMI instructions)
|
|
added to assembler and disassembler (Craig Topper)
|
|
data layout string can encode the natural alignment of the target's stack for better optimization (LangRef.html#datalayout)
|
|
-->
|
|
|
|
<ul>
|
|
|
|
<!--
|
|
<li></li>
|
|
-->
|
|
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<h3>
|
|
<a name="coreimprovements">LLVM IR and Core Improvements</a>
|
|
</h3>
|
|
|
|
<div>
|
|
|
|
<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>
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<h3>
|
|
<a name="optimizer">Optimizer Improvements</a>
|
|
</h3>
|
|
|
|
<div>
|
|
|
|
<p>In addition to a large array of minor performance tweaks and bug fixes, this
|
|
release includes a few major enhancements and additions to the
|
|
optimizers:</p>
|
|
|
|
<ul>
|
|
<li>Information about <a href="BranchWeightMetadata.html">branch probability</a>
|
|
and basic block frequency is now available within LLVM, based on a
|
|
combination of static branch prediction heuristics and
|
|
<code>__builtin_expect</code> calls. That information is currently used for
|
|
register spill placement and if-conversion, with additional optimizations
|
|
planned for future releases. The same framework is intended for eventual
|
|
use with profile-guided optimization.</li>
|
|
</li>
|
|
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<h3>
|
|
<a name="mc">MC Level Improvements</a>
|
|
</h3>
|
|
|
|
<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>
|
|
|
|
<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>
|
|
</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>
|
|
|
|
<!--=========================================================================-->
|
|
<h3>
|
|
<a name="codegen">Target Independent Code Generator Improvements</a>
|
|
</h3>
|
|
|
|
<div>
|
|
|
|
<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>
|
|
-->
|
|
</ul>
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<h3>
|
|
<a name="x86">X86-32 and X86-64 Target Improvements</a>
|
|
</h3>
|
|
|
|
<div>
|
|
|
|
<p>New features and major changes in the X86 target include:</p>
|
|
|
|
<ul>
|
|
<li>The X86 backend, assembler and disassembler now completely support AVX.
|
|
To enable it pass <code>-mavx</code> to the compiler.</li>
|
|
|
|
<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>
|
|
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<h3>
|
|
<a name="ARM">ARM Target Improvements</a>
|
|
</h3>
|
|
|
|
<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>
|
|
</ul>
|
|
</div>
|
|
|
|
|
|
<!--=========================================================================-->
|
|
<h3>
|
|
<a name="MIPS">MIPS Target Improvements</a>
|
|
</h3>
|
|
|
|
<div>
|
|
|
|
<p>New features and major changes in the MIPS target include:</p>
|
|
|
|
<ul>
|
|
<li>Most MIPS32r1 and r2 instructions are now supported.</li>
|
|
<li>LE/BE MIPS32r1/r2 has been tested extensively.</li>
|
|
<li>O32 ABI has been fully tested.</li>
|
|
<li>MIPS backend has migrated to using the MC infrastructure for assembly printing. Initial support for direct object code emission has been implemented too.</li>
|
|
<li>Delay slot filler has been updated. Now it tries to fill delay slots with useful instructions instead of always filling them with NOPs.</li>
|
|
<li>Support for old-style JIT is complete.</li>
|
|
<li>Support for old architectures (MIPS1 and MIPS2) has been removed.</li>
|
|
<li>Initial support for MIPS64 has been added.</li>
|
|
</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>
|
|
</h3>
|
|
|
|
<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>
|
|
|
|
<ul>
|
|
<!--
|
|
<li></li>
|
|
-->
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<!--=========================================================================-->
|
|
<h3>
|
|
<a name="changes">Major Changes and Removed Features</a>
|
|
</h3>
|
|
|
|
<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
|
|
from the previous release.</p>
|
|
|
|
<ul>
|
|
<li>The <code>LLVMC</code> meta compiler driver was removed.</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>.
|
|
</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>
|
|
|
|
<!--=========================================================================-->
|
|
<h3>
|
|
<a name="api_changes">Internal API Changes</a>
|
|
</h3>
|
|
|
|
<div>
|
|
|
|
<p>In addition, many APIs have changed in this release. Some of the major
|
|
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:
|
|
<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>
|
|
</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>
|
|
</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>
|
|
</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>
|
|
|
|
<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>
|
|
</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>
|
|
</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>
|
|
|
|
<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>
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<p>The C backend has numerous problems and is not being actively maintained.
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|
Depending on it for anything serious is not advised.</p>
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|
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<ul>
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<li><a href="http://llvm.org/PR802">The C backend has only basic support for
|
|
inline assembly code</a>.</li>
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|
<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>
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|
|
|
<li>The C backend does not support all exception handling constructs.</li>
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|
<li>The C backend does not support arbitrary precision integers.</li>
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|
</ul>
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</div>
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</div>
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<!-- *********************************************************************** -->
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<h2>
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<a name="additionalinfo">Additional Information</a>
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</h2>
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<!-- *********************************************************************** -->
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<div>
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<p>A wide variety of additional information is available on
|
|
the <a href="http://llvm.org/">LLVM web page</a>, in particular in
|
|
the <a href="http://llvm.org/docs/">documentation</a> section. The web page
|
|
also contains versions of the API documentation which is up-to-date with the
|
|
Subversion version of the source code. You can access versions of these
|
|
documents specific to this release by going into the "<tt>llvm/doc/</tt>"
|
|
directory in the LLVM tree.</p>
|
|
|
|
<p>If you have any questions or comments about LLVM, please feel free to contact
|
|
us via the <a href="http://llvm.org/docs/#maillist"> mailing lists</a>.</p>
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|
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</div>
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<a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
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