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| <body> |
| |
| <h1>LLVM 3.1 Release Notes</h1> |
| |
| <div> |
| <img style="float:right" src="http://llvm.org/img/DragonSmall.png" |
| width="136" height="136" alt="LLVM Dragon Logo"> |
| </div> |
| |
| <ol> |
| <li><a href="#intro">Introduction</a></li> |
| <li><a href="#subproj">Sub-project Status Update</a></li> |
| <li><a href="#externalproj">External Projects Using LLVM 3.1</a></li> |
| <li><a href="#whatsnew">What's New in LLVM?</a></li> |
| <li><a href="GettingStarted.html">Installation Instructions</a></li> |
| <li><a href="#knownproblems">Known Problems</a></li> |
| <li><a href="#additionalinfo">Additional Information</a></li> |
| </ol> |
| |
| <div class="doc_author"> |
| <p>Written by the <a href="http://llvm.org/">LLVM Team</a></p> |
| </div> |
| |
| <h1 style="color:red">These are in-progress notes for the upcoming LLVM 3.1 |
| release.<br> |
| You may prefer the |
| <a href="http://llvm.org/releases/3.0/docs/ReleaseNotes.html">LLVM 3.0 |
| Release Notes</a>.</h1> |
| |
| <!-- *********************************************************************** --> |
| <h2> |
| <a name="intro">Introduction</a> |
| </h2> |
| <!-- *********************************************************************** --> |
| |
| <div> |
| |
| <p>This document contains the release notes for the LLVM Compiler |
| Infrastructure, release 3.1. Here we describe the status of LLVM, including |
| major improvements from the previous release, improvements in various |
| subprojects of LLVM, and some of the current users of the code. |
| All LLVM releases may be downloaded from |
| the <a href="http://llvm.org/releases/">LLVM releases web site</a>.</p> |
| |
| <p>For more information about LLVM, including information about the latest |
| release, please check out the <a href="http://llvm.org/">main LLVM web |
| site</a>. If you have questions or comments, |
| the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM |
| Developer's Mailing List</a> is a good place to send them.</p> |
| |
| <p>Note that if you are reading this file from a Subversion checkout or the main |
| LLVM web page, this document applies to the <i>next</i> release, not the |
| 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> |
| |
| |
| <!-- *********************************************************************** --> |
| <h2> |
| <a name="subproj">Sub-project Status Update</a> |
| </h2> |
| <!-- *********************************************************************** --> |
| |
| <div> |
| |
| <p>The LLVM 3.1 distribution currently consists of code from the core LLVM |
| repository (which roughly includes the LLVM optimizers, code generators and |
| supporting tools), and the Clang repository. In |
| addition to this code, the LLVM Project includes other sub-projects that are |
| in development. Here we include updates on these subprojects.</p> |
| |
| <!--=========================================================================--> |
| <h3> |
| <a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a> |
| </h3> |
| |
| <div> |
| |
| <p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C, |
| C++, and Objective-C languages. Clang aims to provide a better user |
| experience through expressive diagnostics, a high level of conformance to |
| language standards, fast compilation, and low memory use. Like LLVM, Clang |
| provides a modular, library-based architecture that makes it suitable for |
| creating or integrating with other development tools. Clang is considered a |
| production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86 |
| (32- and 64-bit), and for Darwin/ARM targets.</p> |
| |
| <p>In the LLVM 3.1 time-frame, the Clang team has made many improvements:</p> |
| <ul> |
| <li>C++11 support is greatly expanded including lambdas, initializer lists, constexpr, user-defined literals, and atomics.</li> |
| <li>...</li> |
| </ul> |
| |
| <p>For more details about the changes to Clang since the 2.9 release, see the |
| <a href="http://clang.llvm.org/docs/ReleaseNotes.html">Clang release notes</a> |
| </p> |
| |
| |
| <p>If Clang rejects your code but another compiler accepts it, please take a |
| look at the <a href="http://clang.llvm.org/compatibility.html">language |
| compatibility</a> guide to make sure this is not intentional or a known |
| issue.</p> |
| |
| </div> |
| |
| <!--=========================================================================--> |
| <h3> |
| <a name="dragonegg">DragonEgg: GCC front-ends, LLVM back-end</a> |
| </h3> |
| |
| <div> |
| <p><a href="http://dragonegg.llvm.org/">DragonEgg</a> is a |
| <a href="http://gcc.gnu.org/wiki/plugins">gcc plugin</a> that replaces GCC's |
| optimizers and code generators with LLVM's. It works with gcc-4.5 and gcc-4.6 |
| (and partially with gcc-4.7), can target the x86-32/x86-64 and ARM processor |
| families, and has been successfully used on the Darwin, FreeBSD, KFreeBSD, |
| Linux and OpenBSD platforms. It fully supports Ada, C, C++ and Fortran. It |
| has partial support for Go, Java, Obj-C and Obj-C++.</p> |
| |
| <p>The 3.1 release has the following notable changes:</p> |
| |
| <ul> |
| |
| <li>Partial support for gcc-4.7. Ada support is poor, but other languages work |
| fairly well.</li> |
| |
| <li>Support for ARM processors. Some essential gcc headers that are needed to |
| build DragonEgg for ARM are not installed by gcc. To work around this, |
| copy the missing headers from the gcc source tree.</li> |
| |
| <li>Better optimization for Fortran by exploiting the fact that Fortran scalar |
| arguments have 'restrict' semantics.</li> |
| |
| <li>Better optimization for all languages by passing information about type |
| aliasing and type ranges to the LLVM optimizers.</li> |
| |
| <li>A regression test-suite was added.</li> |
| |
| </ul> |
| |
| </div> |
| |
| <!--=========================================================================--> |
| <h3> |
| <a name="compiler-rt">compiler-rt: Compiler Runtime Library</a> |
| </h3> |
| |
| <div> |
| |
| <p>The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a> |
| is a simple library that provides an implementation of the low-level |
| target-specific hooks required by code generation and other runtime |
| components. For example, when compiling for a 32-bit target, converting a |
| double to a 64-bit unsigned integer is compiled into a runtime call to the |
| "__fixunsdfdi" 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>....</p> |
| |
| </div> |
| |
| <!--=========================================================================--> |
| <h3> |
| <a name="lldb">LLDB: Low Level Debugger</a> |
| </h3> |
| |
| <div> |
| |
| <p>LLDB is a ground-up implementation of a command line debugger, as well as a |
| debugger API that can be used from other applications. LLDB makes use of the |
| Clang parser to provide high-fidelity expression parsing (particularly for |
| C++) and uses the LLVM JIT for target support.</p> |
| |
| <p>...</p> |
| |
| </div> |
| |
| <!--=========================================================================--> |
| <h3> |
| <a name="libc++">libc++: C++ Standard Library</a> |
| </h3> |
| |
| <div> |
| |
| <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> |
| |
| <p>...</p> |
| |
| </div> |
| |
| <!--=========================================================================--> |
| <h3> |
| <a name="vmkit">VMKit</a> |
| </h3> |
| |
| <div> |
| |
| <p>The <a href="http://vmkit.llvm.org/">VMKit project</a> is an |
| implementation of a Java Virtual Machine (Java VM or JVM) that uses LLVM for |
| static and just-in-time compilation. |
| |
| <p>In the LLVM 3.1 time-frame, VMKit has had significant improvements on both |
| runtime and startup performance:</p> |
| |
| <ul> |
| <li>...</li> |
| </ul> |
| |
| </div> |
| |
| |
| <!--=========================================================================--> |
| <h3> |
| <a name="Polly">Polly: Polyhedral Optimizer</a> |
| </h3> |
| |
| <div> |
| |
| <p><a href="http://polly.llvm.org/">Polly</a> is an <em>experimental</em> |
| optimizer for data locality and parallelism. It currently provides high-level |
| loop optimizations and automatic parallelisation (using the OpenMP run time). |
| Work in the area of automatic SIMD and accelerator code generation was |
| started. |
| |
| <p>Within the LLVM 3.1 time-frame there were the following highlights:</p> |
| |
| <ul> |
| <li>Polly became an official LLVM project</li> |
| <li>Polly can be loaded directly into clang (Enabled by '-O3 -mllvm -polly' |
| )</li> |
| <li>An automatic scheduling optimizer (derived from <a |
| href="http://pluto-compiler.sourceforge.net/">Pluto</a>) was integrated. It |
| performs loop transformations to optimize for data-locality and parallelism. |
| The transformations include, but are not limited to interchange, fusion, |
| fission, skewing and tiling. |
| </li> |
| </ul> |
| |
| </div> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
| <h2> |
| <a name="externalproj">External Open Source Projects Using LLVM 3.1</a> |
| </h2> |
| <!-- *********************************************************************** --> |
| |
| <div> |
| |
| <p>An exciting aspect of LLVM is that it is used as an enabling technology for |
| a lot of other language and tools projects. This section lists some of the |
| projects that have already been updated to work with LLVM 3.1.</p> |
| |
| <h3>Pure</h3> |
| |
| <p>Pure (http://pure-lang.googlecode.com/) 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 0.54 has been tested and is known to work with LLVM 3.1 (and |
| continues to work with older LLVM releases >= 2.5).</p> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
| <h2> |
| <a name="whatsnew">What's New in LLVM 3.1?</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. |
| Integrated assembler on by default for arm/thumb? |
| |
| --> |
| |
| <!-- Near dead: |
| Analysis/RegionInfo.h + Dom Frontiers |
| SparseBitVector: used in LiveVar. |
| llvm/lib/Archive - replace with lib object? |
| --> |
| |
| <p>LLVM 3.1 includes several major changes and big features:</p> |
| |
| <ul> |
| <li><a href="../tools/clang/docs/AddressSanitizer.html">AddressSanitizer</a>, |
| a fast memory error detector.</li> |
| <li><a href="CodeGenerator.html#machineinstrbundle">MachineInstr Bundles</a>, |
| Support to model instruction bundling / packing.</li> |
| <li><a href="#armintegratedassembler">ARM Integrated Assembler</a>, |
| A full featured assembler and direct-to-object support for ARM.</li> |
| <li><a href="#blockplacement">Basic Block Placement</a> |
| Probability driven basic block placement.</li> |
| <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> |
| |
| <ul> |
| <li>IR support for half float</li> |
| <li>IR support for vectors of pointers, including vector GEPs.</li> |
| <li>Module flags have been introduced. They convey information about the |
| module as a whole to LLVM subsystems.</li> |
| <li>Loads can now have range metadata attached to them to describe the |
| possible values being loaded.</li> |
| <li>Inline cost heuristics have been completely overhauled and now closely |
| model constant propagation through call sites, disregard trivially dead |
| code costs, and can model C++ STL iterator patterns.</li> |
| <li>....</li> |
| </ul> |
| </div> |
| |
| <!--=========================================================================--> |
| <h3> |
| <a name="optimizer">Optimizer Improvements</a> |
| </h3> |
| |
| <div> |
| |
| <p>In addition to many minor performance tweaks and bug fixes, this |
| release includes a few major enhancements and additions to the |
| optimizers:</p> |
| |
| <ul> |
| <li>The loop unroll pass now is able to unroll loops with run-time trip counts. |
| This feature is turned off by default, and is enabled with the |
| <code>-unroll-runtime</code> flag.</li> |
| <li>A new basic-block autovectorization pass is available. Pass |
| <code>-vectorize</code> to run this pass along with some associated |
| post-vectorization cleanup passes. For more information, see the EuroLLVM |
| 2012 slides: <a href="http://llvm.org/devmtg/2012-04-12/Slides/Hal_Finkel.pdf"> |
| Autovectorization with LLVM</a>.</li> |
| <li>....</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. For more information, please see |
| the <a href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro |
| to the LLVM MC Project Blog Post</a>.</p> |
| |
| <ul> |
| <li>....</li> |
| </ul> |
| |
| </div> |
| |
| <!--=========================================================================--> |
| <h3> |
| <a name="codegen">Target Independent Code Generator Improvements</a> |
| </h3> |
| |
| <div> |
| |
| <p>We have changed the way that the Type Legalizer legalizes vectors. The type |
| legalizer now attempts to promote integer elements. This enabled the |
| implementation of vector-select. Additionally, we see a performance boost on |
| workloads which use vectors of chars and shorts, since they are now promoted |
| to 32-bit types, which are better supported by the SIMD instruction set. |
| Floating point types are still widened as before.</p> |
| |
| |
| <p>We have put a significant amount of work into the code generator |
| infrastructure, which allows us to implement more aggressive algorithms and |
| make it run faster:</p> |
| |
| <ul> |
| <li>TableGen can now synthesize register classes that are only needed to |
| represent combinations of constraints from instructions and sub-registers. |
| The synthetic register classes inherit most of their properties form their |
| closest user-defined super-class.</li> |
| <li><code>MachineRegisterInfo</code> now allows the reserved registers to be |
| frozen when register allocation starts. Target hooks should use the |
| <code>MRI->canReserveReg(FramePtr)</code> method to avoid accidentally |
| disabling frame pointer elimination during register allocation.</li> |
| <li>A new kind of <code>MachineOperand</code> provides a compact |
| representation of large clobber lists on call instructions. The register |
| mask operand references a bit mask of preserved registers. Everything else |
| is clobbered.</li> |
| </ul> |
| |
| <p> We added new TableGen infrastructure to support bundling for |
| Very Long Instruction Word (VLIW) architectures. TableGen can now |
| automatically generate a deterministic finite automaton from a VLIW |
| target's schedule description which can be queried to determine |
| legal groupings of instructions in a bundle.</p> |
| |
| <p> We have added a new target independent VLIW packetizer based on the |
| DFA infrastructure to group machine instructions into bundles.</p> |
| |
| </div> |
| |
| <h4> |
| <a name="blockplacement">Basic Block Placement</a> |
| </h4> |
| <div> |
| <p>A probability based block placement and code layout algorithm was added to |
| LLVM's code generator. This layout pass supports probabilities derived from |
| static heuristics as well as source code annotations such as |
| <code>__builtin_expect</code>.</p> |
| </div> |
| |
| <!--=========================================================================--> |
| <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>Bug fixes and improved support for AVX1</li> |
| <li>Support for AVX2 (still incomplete at this point)</li> |
| <li>Call instructions use the new register mask operands for faster compile |
| times and better support for different calling conventions. The old WINCALL |
| instructions are no longer needed.</li> |
| <li>DW2 Exception Handling is enabled on Cygwin and MinGW.</li> |
| <li>Support for implicit TLS model used with MS VC runtime</li> |
| </ul> |
| |
| </div> |
| |
| <!--=========================================================================--> |
| <h3> |
| <a name="ARM">ARM Target Improvements</a> |
| </h3> |
| |
| <div> |
| |
| <p>New features of the ARM target include:</p> |
| |
| <ul> |
| <li>The constant island pass now supports basic block and constant pool entry |
| alignments greater than 4 bytes.</li> |
| <li>On Darwin, the ARM target now has a full-featured integrated assembler. |
| </li> |
| </ul> |
| |
| <h4> |
| <a name="armintegratedassembler">ARM Integrated Assembler</a> |
| </h4> |
| <div> |
| <p>The ARM target now includes a full featured macro assembler, including |
| direct-to-object module support for clang. The assembler is currently enabled |
| by default for Darwin only pending testing and any additional necessary |
| platform specific support for Linux.</p> |
| |
| <p>Full support is included for Thumb1, Thumb2 and ARM modes, along with |
| subtarget and CPU specific extensions for VFP2, VFP3 and NEON.</p> |
| |
| <p>The assembler is Unified Syntax only (see ARM Architecural Reference Manual |
| for details). While there is some, and growing, support for pre-unfied (divided) |
| syntax, there are still significant gaps in that support.</p> |
| </div> |
| |
| </div> |
| <!--=========================================================================--> |
| <h3> |
| <a name="MIPS">MIPS Target Improvements</a> |
| </h3> |
| |
| <div> |
| |
| <p>This release has seen major new work on just about every aspect of the MIPS |
| backend. Some of the major new features include:</p> |
| |
| <ul> |
| <li>....</li> |
| </ul> |
| </div> |
| |
| <!--=========================================================================--> |
| <h3> |
| <a name="OtherTS">Other Target Specific Improvements</a> |
| </h3> |
| |
| <div> |
| |
| <p>Support for Qualcomm's Hexagon VLIW processor has been added.</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 3.1, this section lists some "gotchas" that you may run into upgrading |
| from the previous release.</p> |
| |
| <ul> |
| <li>LLVM 3.1 removes support for reading LLVM 2.9 bitcode files. Going |
| forward, we aim for all future versions of LLVM to read bitcode files and |
| <tt>.ll</tt> files produced by LLVM 3.0 and later.</li> |
| <li>The <tt>unwind</tt> instruction is now gone. With the introduction of the |
| new exception handling system in LLVM 3.0, the <tt>unwind</tt> instruction |
| became obsolete.</li> |
| <li>LLVM 3.0 and earlier automatically added the returns_twice fo functions |
| like setjmp based on the name. This functionality was removed in 3.1. |
| This affects Clang users, if -ffreestanding is used.</li> |
| <li>....</li> |
| </ul> |
| |
| </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>Target specific options have been moved from global variables to members |
| on the new <code>TargetOptions</code> class, which is local to each |
| <code>TargetMachine</code>. As a consequence, the associated flags will |
| no longer be accepted by <tt>clang -mllvm</tt>. This includes: |
| <ul> |
| <li><code>llvm::PrintMachineCode</code></li> |
| <li><code>llvm::NoFramePointerElim</code></li> |
| <li><code>llvm::NoFramePointerElimNonLeaf</code></li> |
| <li><code>llvm::DisableFramePointerElim(const MachineFunction &)</code></li> |
| <li><code>llvm::LessPreciseFPMADOption</code></li> |
| <li><code>llvm::LessPrecideFPMAD()</code></li> |
| <li><code>llvm::NoExcessFPPrecision</code></li> |
| <li><code>llvm::UnsafeFPMath</code></li> |
| <li><code>llvm::NoInfsFPMath</code></li> |
| <li><code>llvm::NoNaNsFPMath</code></li> |
| <li><code>llvm::HonorSignDependentRoundingFPMathOption</code></li> |
| <li><code>llvm::HonorSignDependentRoundingFPMath()</code></li> |
| <li><code>llvm::UseSoftFloat</code></li> |
| <li><code>llvm::FloatABIType</code></li> |
| <li><code>llvm::NoZerosInBSS</code></li> |
| <li><code>llvm::JITExceptionHandling</code></li> |
| <li><code>llvm::JITEmitDebugInfo</code></li> |
| <li><code>llvm::JITEmitDebugInfoToDisk</code></li> |
| <li><code>llvm::GuaranteedTailCallOpt</code></li> |
| <li><code>llvm::StackAlignmentOverride</code></li> |
| <li><code>llvm::RealignStack</code></li> |
| <li><code>llvm::DisableJumpTables</code></li> |
| <li><code>llvm::EnableFastISel</code></li> |
| <li><code>llvm::getTrapFunctionName()</code></li> |
| <li><code>llvm::EnableSegmentedStacks</code></li> |
| </ul></li> |
| <li>The MDBuilder class has been added to simplify the creation of |
| metadata.</li> |
| <li>....</li> |
| </ul> |
| |
| </div> |
| |
| <!--=========================================================================--> |
| <h3> |
| <a name="tools_changes">Tools Changes</a> |
| </h3> |
| |
| <div> |
| |
| <p>In addition, some tools have changed in this release. Some of the changes |
| are:</p> |
| |
| |
| <ul> |
| <li>llvm-stress is a command line tool for generating random .ll files to fuzz |
| different LLVM components. </li> |
| <li>llvm-ld has been removed. Use llvm-link or Clang instead.</li> |
| <li>....</li> |
| </ul> |
| |
| <ul> |
| <li>....</li> |
| </ul> |
| |
| </div> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
| <h2> |
| <a name="knownproblems">Known Problems</a> |
| </h2> |
| <!-- *********************************************************************** --> |
| |
| <div> |
| |
| <p>LLVM is generally a production quality compiler, and is used by a broad range |
| of applications and shipping in many products. That said, not every |
| subsystem is as mature as the aggregate, particularly the more obscure |
| targets. If you run into a problem, please check the <a |
| href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if |
| there isn't already one or ask on the <a |
| href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev |
| list</a>.</p> |
| |
| <p>Known problem areas include:</p> |
| |
| <ul> |
| <li>The Alpha, Blackfin, CellSPU, MSP430, PTX, SystemZ and |
| XCore backends are experimental, and the Alpha, Blackfin and SystemZ |
| targets have already been removed from mainline.</li> |
| |
| <li>The integrated assembler, disassembler, and JIT is not supported by |
| several targets. If an integrated assembler is not supported, then a |
| system assembler is required. For more details, see the <a |
| href="CodeGenerator.html#targetfeatures">Target Features Matrix</a>. |
| </li> |
| |
| <li>The C backend has numerous problems and is not being actively maintained. |
| Depending on it for anything serious is not advised.</li> |
| </ul> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
| <h2> |
| <a name="additionalinfo">Additional Information</a> |
| </h2> |
| <!-- *********************************************************************** --> |
| |
| <div> |
| |
| <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> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
| |
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