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| author | Tanya Lattner <tonic@nondot.org> | 2009-10-23 06:16:18 +0000 |
|---|---|---|
| committer | Tanya Lattner <tonic@nondot.org> | 2009-10-23 06:16:18 +0000 |
| commit | 1b769552afd55231dd0b5e5d2f614f801ccbe515 (patch) | |
| tree | 1fecc145c2dd1b613bc776f06589791019be5912 /docs/ReleaseNotes.html | |
| parent | 94ea8e3ce8cab765ed3b783d35c48b83af9ec3dc (diff) | |
Merge in release notes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_26@84933 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs/ReleaseNotes.html')
| -rw-r--r-- | docs/ReleaseNotes.html | 1045 |
1 files changed, 718 insertions, 327 deletions
diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html index bdaba71b74..95866dd625 100644 --- a/docs/ReleaseNotes.html +++ b/docs/ReleaseNotes.html @@ -4,17 +4,17 @@ <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <link rel="stylesheet" href="llvm.css" type="text/css"> - <title>LLVM 2.5 Release Notes</title> + <title>LLVM 2.6 Release Notes</title> </head> <body> -<div class="doc_title">LLVM 2.5 Release Notes</div> +<div class="doc_title">LLVM 2.6 Release Notes</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 2.5</a></li> - <li><a href="#whatsnew">What's New in LLVM 2.5?</a></li> + <li><a href="#externalproj">External Projects Using LLVM 2.6</a></li> + <li><a href="#whatsnew">What's New in LLVM 2.6?</a></li> <li><a href="GettingStarted.html">Installation Instructions</a></li> <li><a href="#portability">Portability and Supported Platforms</a></li> <li><a href="#knownproblems">Known Problems</a></li> @@ -34,7 +34,7 @@ <div class="doc_text"> <p>This document contains the release notes for the LLVM Compiler -Infrastructure, release 2.5. Here we describe the status of LLVM, including +Infrastructure, release 2.6. Here we describe the status of LLVM, including major improvements from the previous release and significant known problems. All LLVM releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM releases web site</a>.</p> @@ -51,25 +51,37 @@ 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> - -<!-- Unfinished features in 2.5: - Machine LICM - Machine Sinking - target-specific intrinsics - gold lto plugin - pre-alloc splitter, strong phi elim - <tt>llc -enable-value-prop</tt>, propagation of value info - (sign/zero ext info) from one MBB to another - debug info for optimized code - interpreter + libffi + + +<!-- +Almost dead code. + include/llvm/Analysis/LiveValues.h => Dan + lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8. + llvm/Analysis/PointerTracking.h => Edwin wants this, consider for 2.8. +--> + + +<!-- Unfinished features in 2.6: + gcc plugin. + strong phi elim + variable debug info for optimized code postalloc scheduler: anti dependence breaking, hazard recognizer? - -initial support for debug line numbers when optimization enabled, not useful in - 2.5 but will be for 2.6. - + metadata + loop dependence analysis + ELF Writer? How stable? + <li>PostRA scheduler improvements, ARM adoption (David Goodwin).</li> + 2.7 supports the GDB 7.0 jit interfaces for debug info. + 2.7 eliminates ADT/iterator.h --> <!-- for announcement email: + Logo web page. + llvm devmtg + compiler_rt + KLEE web page at klee.llvm.org + Many new papers added to /pubs/ + Mention gcc plugin. + --> <!-- *********************************************************************** --> @@ -80,12 +92,11 @@ initial support for debug line numbers when optimization enabled, not useful in <div class="doc_text"> <p> -The LLVM 2.5 distribution currently consists of code from the core LLVM -repository —which roughly includes the LLVM optimizers, code generators -and supporting tools — and the llvm-gcc repository. In addition to this -code, the LLVM Project includes other sub-projects that are in development. The -two which are the most actively developed are the <a href="#clang">Clang -Project</a> and the <a href="#vmkit">VMKit Project</a>. +The LLVM 2.6 distribution currently consists of code from the core LLVM +repository (which roughly includes the LLVM optimizers, code generators +and supporting tools), the Clang repository and the llvm-gcc repository. In +addition to this code, the LLVM Project includes other sub-projects that are in +development. Here we include updates on these subprojects. </p> </div> @@ -99,37 +110,30 @@ Project</a> and the <a href="#vmkit">VMKit Project</a>. <div class="doc_text"> <p>The <a href="http://clang.llvm.org/">Clang project</a> is an effort to build -a set of new 'LLVM native' front-end technologies for the LLVM optimizer and -code generator. While Clang is not included in the LLVM 2.5 release, it is -continuing to make major strides forward in all areas. Its C and Objective-C -parsing and code generation support is now very solid. For example, it is -capable of successfully building many real-world applications for X86-32 -and X86-64, -including the <a href="http://wiki.freebsd.org/BuildingFreeBSDWithClang">FreeBSD -kernel</a> and <a href="http://gcc.gnu.org/gcc-4.2/">gcc 4.2</a>. C++ is also -making <a href="http://clang.llvm.org/cxx_status.html">incredible progress</a>, -and work on templates has recently started. If you are -interested in fast compiles and good diagnostics, we encourage you to try it out -by <a href="http://clang.llvm.org/get_started.html">building from mainline</a> -and reporting any issues you hit to the <a +a set of new 'LLVM native' front-end technologies for the C family of languages. +LLVM 2.6 is the first release to officially include Clang, and it provides a +production quality C and Objective-C compiler. If you are interested in <a +href="http://clang.llvm.org/performance.html">fast compiles</a> and +<a href="http://clang.llvm.org/diagnostics.html">good diagnostics</a>, we +encourage you to try it out. Clang currently compiles typical Objective-C code +3x faster than GCC and compiles C code about 30% faster than GCC at -O0 -g +(which is when the most pressure is on the frontend).</p> + +<p>In addition to supporting these languages, C++ support is also <a +href="http://clang.llvm.org/cxx_status.html">well under way</a>, and mainline +Clang is able to parse the libstdc++ 4.2 headers and even codegen simple apps. +If you are interested in Clang C++ support or any other Clang feature, we +strongly encourage you to get involved on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">Clang front-end mailing list</a>.</p> -<p>In the LLVM 2.5 time-frame, the Clang team has made many improvements:</p> +<p>In the LLVM 2.6 time-frame, the Clang team has made many improvements:</p> <ul> -<li>Clang now has a new driver, which is focused on providing a GCC-compatible - interface.</li> -<li>The X86-64 ABI is now supported, including support for the Apple - 64-bit Objective-C runtime and zero cost exception handling.</li> -<li>Precompiled header support is now implemented.</li> -<li>Objective-C support is significantly improved beyond LLVM 2.4, supporting - many features, such as Objective-C Garbage Collection.</li> -<li>Variable length arrays are now fully supported.</li> -<li>C99 designated initializers are now fully supported.</li> -<li>Clang now includes all major compiler headers, including a - redesigned <i>tgmath.h</i> and several more intrinsic headers.</li> -<li>Many many bugs are fixed and many features have been added.</li> +<li>C and Objective-C support are now considered production quality.</li> +<li>AuroraUX, FreeBSD and OpenBSD are now supported.</li> +<li>Most of Objective-C 2.0 is now supported with the GNU runtime.</li> +<li>Many many bugs are fixed and lots of features have been added.</li> </ul> </div> @@ -140,19 +144,18 @@ list</a>.</p> <div class="doc_text"> -<p>Previously announced in the last LLVM release, the Clang project also +<p>Previously announced in the 2.4 and 2.5 LLVM releases, the Clang project also includes an early stage static source code analysis tool for <a href="http://clang.llvm.org/StaticAnalysis.html">automatically finding bugs</a> -in C and Objective-C programs. The tool performs a growing set of checks to find +in C and Objective-C programs. The tool performs checks to find bugs that occur on a specific path within a program.</p> -<p>In the LLVM 2.5 time-frame there have been many significant improvements to -the analyzer's core path simulation engine and machinery for generating -path-based bug reports to end-users. Particularly noteworthy improvements -include experimental support for full field-sensitivity and reasoning about heap -objects as well as an improved value-constraints subengine that does a much -better job of reasoning about inequality relationships (e.g., <tt>x > 2</tt>) -between variables and constants. +<p>In the LLVM 2.6 time-frame, the analyzer core has undergone several important +improvements and cleanups and now includes a new <em>Checker</em> interface that +is intended to eventually serve as a basis for domain-specific checks. Further, +in addition to generating HTML files for reporting analysis results, the +analyzer can now also emit bug reports in a structured XML format that is +intended to be easily readable by other programs.</p> <p>The set of checks performed by the static analyzer continues to expand, and future plans for the tool include full source-level inter-procedural analysis @@ -170,44 +173,191 @@ this project is encouraged to get involved!</p> <div class="doc_text"> <p> The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of -a JVM and a CLI Virtual Machines (Microsoft .NET is an -implementation of the CLI) using the Just-In-Time compiler of LLVM.</p> +a JVM and a CLI Virtual Machine (Microsoft .NET is an +implementation of the CLI) using LLVM for static and just-in-time +compilation.</p> -<p>Following LLVM 2.5, VMKit has its second release that you can find on its -<a href="http://vmkit.llvm.org/releases/">webpage</a>. The release includes +<p> +VMKit version 0.26 builds with LLVM 2.6 and you can find it on its +<a href="http://vmkit.llvm.org/releases/">web page</a>. The release includes bug fixes, cleanup and new features. The major changes are:</p> <ul> -<li>Ahead of Time compiler: compiles .class files to llvm .bc. VMKit uses this -functionality to native compile the standard classes (e.g. java.lang.String). -Users can compile AoT .class files into dynamic libraries and run them with the -help of VMKit.</li> +<li>A new llcj tool to generate shared libraries or executables of Java + files.</li> +<li>Cooperative garbage collection. </li> +<li>Fast subtype checking (paper from Click et al [JGI'02]). </li> +<li>Implementation of a two-word header for Java objects instead of the original + three-word header. </li> +<li>Better Java specification-compliance: division by zero checks, stack + overflow checks, finalization and references support. </li> -<li>New exception model: the dwarf exception model is very slow for -exception-intensive applications, so the JVM has had a new implementation of -exceptions which check at each function call if an exception happened. There is -a low performance penalty on applications without exceptions, but it is a big -gain for exception-intensive applications. For example the jack benchmark in -Spec JVM98 is 6x faster (performance gain of 83%).</li> +</ul> +</div> -<li>User-level management of thread stacks, so that thread local data access -at runtime is fast and portable. </li> -<li>Implementation of biased locking for faster object synchronizations at -runtime.</li> +<!--=========================================================================--> +<div class="doc_subsection"> +<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a> +</div> -<li>New support for OSX/X64, Linux/X64 (with the Boehm GC) and Linux/ppc32.</li> +<div class="doc_text"> +<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> -</ul> +<p> +All of the code in the compiler-rt project is available under the standard LLVM +License, a "BSD-style" license.</p> + +</div> + +<!--=========================================================================--> +<div class="doc_subsection"> +<a name="klee">KLEE: Symbolic Execution and Automatic Test Case Generator</a> </div> +<div class="doc_text"> +<p> +The new LLVM <a href="http://klee.llvm.org/">KLEE project</a> is a symbolic +execution framework for programs in LLVM bitcode form. KLEE tries to +symbolically evaluate "all" paths through the application and records state +transitions that lead to fault states. This allows it to construct testcases +that lead to faults and can even be used to verify algorithms. For more +details, please see the <a +href="http://llvm.org/pubs/2008-12-OSDI-KLEE.html">OSDI 2008 paper</a> about +KLEE.</p> + +</div> + +<!--=========================================================================--> +<div class="doc_subsection"> +<a name="dragonegg">DragonEgg: GCC-4.5 as an LLVM frontend</a> +</div> + +<div class="doc_text"> +<p> +The goal of <a href="http://dragonegg.llvm.org/">DragonEgg</a> is to make +gcc-4.5 act like llvm-gcc without requiring any gcc modifications whatsoever. +<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a shared library (dragonegg.so) +that is loaded by gcc at runtime. It uses the new gcc plugin architecture to +disable the GCC optimizers and code generators, and schedule the LLVM optimizers +and code generators (or direct output of LLVM IR) instead. Currently only Linux +and Darwin are supported, and only on x86-32 and x86-64. It should be easy to +add additional unix-like architectures and other processor families. In theory +it should be possible to use <a href="http://dragonegg.llvm.org/">DragonEgg</a> +with any language supported by gcc, however only C and Fortran work well for the +moment. Ada and C++ work to some extent, while Java, Obj-C and Obj-C++ are so +far entirely untested. Since gcc-4.5 has not yet been released, neither has +<a href="http://dragonegg.llvm.org/">DragonEgg</a>. To build +<a href="http://dragonegg.llvm.org/">DragonEgg</a> you will need to check out the +development versions of <a href="http://gcc.gnu.org/svn.html/"> gcc</a>, +<a href="http://llvm.org/docs/GettingStarted.html#checkout">llvm</a> and +<a href="http://dragonegg.llvm.org/">DragonEgg</a> from their respective +subversion repositories, and follow the instructions in the +<a href="http://dragonegg.llvm.org/">DragonEgg</a> README. +</p> + +</div> + + +<!--=========================================================================--> +<div class="doc_subsection"> +<a name="mc">llvm-mc: Machine Code Toolkit</a> +</div> + +<div class="doc_text"> +<p> +The LLVM Machine Code (MC) Toolkit project is a (very early) effort to build +better tools for dealing with machine code, object file formats, etc. The idea +is to be able to generate most of the target specific details of assemblers and +disassemblers from existing LLVM target .td files (with suitable enhancements), +and to build infrastructure for reading and writing common object file formats. +One of the first deliverables is to build a full assembler and integrate it into +the compiler, which is predicted to substantially reduce compile time in some +scenarios. +</p> + +<p>In the LLVM 2.6 timeframe, the MC framework has grown to the point where it +can reliably parse and pretty print (with some encoding information) a +darwin/x86 .s file successfully, and has the very early phases of a Mach-O +assembler in progress. Beyond the MC framework itself, major refactoring of the +LLVM code generator has started. The idea is to make the code generator reason +about the code it is producing in a much more semantic way, rather than a +textual way. For example, the code generator now uses MCSection objects to +represent section assignments, instead of text strings that print to .section +directives.</p> + +<p>MC is an early and ongoing project that will hopefully continue to lead to +many improvements in the code generator and build infrastructure useful for many +other situations. +</p> + +</div> + + <!-- *********************************************************************** --> <div class="doc_section"> - <a name="externalproj">External Projects Using LLVM 2.5</a> + <a name="externalproj">External Open Source Projects Using LLVM 2.6</a> </div> <!-- *********************************************************************** --> +<div class="doc_text"> + +<p>An exciting aspect of LLVM is that it is used as an enabling technology for + a lot of other language and tools projects. This section lists some of the + projects that have already been updated to work with LLVM 2.6.</p> +</div> + + +<!--=========================================================================--> +<div class="doc_subsection"> +<a name="Rubinius">Rubinius</a> +</div> + +<div class="doc_text"> +<p><a href="http://github.com/evanphx/rubinius">Rubinius</a> is an environment +for running Ruby code which strives to write as much of the core class +implementation in Ruby as possible. Combined with a bytecode interpreting VM, it +uses LLVM to optimize and compile ruby code down to machine code. Techniques +such as type feedback, method inlining, and uncommon traps are all used to +remove dynamism from ruby execution and increase performance.</p> + +<p>Since LLVM 2.5, Rubinius has made several major leaps forward, implementing +a counter based JIT, type feedback and speculative method inlining. +</p> + +</div> + +<!--=========================================================================--> +<div class="doc_subsection"> +<a name="macruby">MacRuby</a> +</div> + +<div class="doc_text"> + +<p> +<a href="http://macruby.org">MacRuby</a> is an implementation of Ruby on top of +core Mac OS X technologies, such as the Objective-C common runtime and garbage +collector and the CoreFoundation framework. It is principally developed by +Apple and aims at enabling the creation of full-fledged Mac OS X applications. +</p> + +<p> +MacRuby uses LLVM for optimization passes, JIT and AOT compilation of Ruby +expressions. It also uses zero-cost DWARF exceptions to implement Ruby exception +handling.</p> + +</div> + + <!--=========================================================================--> <div class="doc_subsection"> <a name="pure">Pure</a> @@ -224,12 +374,8 @@ built-in list and matrix support (including list and matrix comprehensions) and an easy-to-use C interface. The interpreter uses LLVM as a backend to JIT-compile Pure programs to fast native code.</p> -<p>In addition to the usual algebraic data structures, Pure also has -MATLAB-style matrices in order to support numeric computations and signal -processing in an efficient way. Pure is mainly aimed at mathematical -applications right now, but it has been designed as a general purpose language. -The dynamic interpreter environment and the C interface make it possible to use -it as a kind of functional scripting language for many application areas. +<p>Pure versions 0.31 and later have been tested and are known to work with +LLVM 2.6 (and continue to work with older LLVM releases >= 2.3 as well). </p> </div> @@ -243,11 +389,11 @@ it as a kind of functional scripting language for many application areas. <p> <a href="http://www.dsource.org/projects/ldc">LDC</a> is an implementation of the D Programming Language using the LLVM optimizer and code generator. -The LDC project works great with the LLVM 2.5 release. General improvements in +The LDC project works great with the LLVM 2.6 release. General improvements in this cycle have included new inline asm constraint handling, better debug info -support, general bugfixes, and better x86-64 support. This has allowed -some major improvements in LDC, getting us much closer to being as +support, general bug fixes and better x86-64 support. This has allowed +some major improvements in LDC, getting it much closer to being as fully featured as the original DMD compiler from DigitalMars. </p> </div> @@ -258,142 +404,160 @@ fully featured as the original DMD compiler from DigitalMars. </div> <div class="doc_text"> -<p><a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open +<p> +<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open source implementation of the PHP programming -language that uses LLVM for its optimizer, JIT, and static compiler. This is a +language that uses LLVM for its optimizer, JIT and static compiler. This is a reimplementation of an earlier project that is now based on LLVM.</p> </div> - -<!-- *********************************************************************** --> -<div class="doc_section"> - <a name="whatsnew">What's New in LLVM 2.5?</a> +<!--=========================================================================--> +<div class="doc_subsection"> +<a name="UnladenSwallow">Unladen Swallow</a> </div> -<!-- *********************************************************************** --> <div class="doc_text"> - -<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> +<p> +<a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a +branch of <a href="http://python.org/">Python</a> intended to be fully +compatible and significantly faster. It uses LLVM's optimization passes and JIT +compiler.</p> </div> <!--=========================================================================--> <div class="doc_subsection"> -<a name="majorfeatures">Major New Features</a> +<a name="llvm-lua">llvm-lua</a> </div> <div class="doc_text"> +<p> +<a href="http://code.google.com/p/llvm-lua/">LLVM-Lua</a> uses LLVM to add JIT +and static compiling support to the Lua VM. Lua bytecode is analyzed to +remove type checks, then LLVM is used to compile the bytecode down to machine +code.</p> +</div> -<p>LLVM 2.5 includes several major new capabilities:</p> +<!--=========================================================================--> +<div class="doc_subsection"> +<a name="icedtea">IcedTea Java Virtual Machine Implementation</a> +</div> -<ul> -<li>LLVM 2.5 includes a brand new <a -href="http://en.wikipedia.org/wiki/XCore">XCore</a> backend.</li> +<div class="doc_text"> +<p> +<a href="http://icedtea.classpath.org/wiki/Main_Page">IcedTea</a> provides a +harness to build OpenJDK using only free software build tools and to provide +replacements for the not-yet free parts of OpenJDK. One of the extensions that +IcedTea provides is a new JIT compiler named <a +href="http://icedtea.classpath.org/wiki/ZeroSharkFaq">Shark</a> which uses LLVM +to provide native code generation without introducing processor-dependent +code. +</p> +</div> -<li>llvm-gcc now generally supports the GFortran front-end, and the precompiled -release binaries now support Fortran, even on Mac OS/X.</li> -<li>CMake is now used by the <a href="GettingStartedVS.html">LLVM build process -on Windows</a>. It automatically generates Visual Studio project files (and -more) from a set of simple text files. This makes it much easier to -maintain. In time, we'd like to standardize on CMake for everything.</li> -<li>LLVM 2.5 now uses (and includes) Google Test for unit testing.</li> +<!-- *********************************************************************** --> +<div class="doc_section"> + <a name="whatsnew">What's New in LLVM 2.6?</a> +</div> +<!-- *********************************************************************** --> -<li>The LLVM native code generator now supports arbitrary precision integers. -Types like <tt>i33</tt> have long been valid in the LLVM IR, but were previously -only supported by the interpreter. Note that the C backend still does not -support these.</li> +<div class="doc_text"> -<li>LLVM 2.5 no longer uses 'bison,' so it is easier to build on Windows.</li> -</ul> +<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> </div> - <!--=========================================================================--> <div class="doc_subsection"> -<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a> +<a name="majorfeatures">Major New Features</a> </div> <div class="doc_text"> -<p>LLVM fully supports the llvm-gcc 4.2 front-end, which marries the GCC -front-ends and driver with the LLVM optimizer and code generator. It currently -includes support for the C, C++, Objective-C, Ada, and Fortran front-ends.</p> +<p>LLVM 2.6 includes several major new capabilities:</p> <ul> -<li>In this release, the GCC inliner is completely disabled. Previously the GCC -inliner was used to handle always-inline functions and other cases. This caused -problems with code size growth, and it is completely disabled in this -release.</li> - -<li>llvm-gcc (and LLVM in general) now support code generation for stack -canaries, which is an effective form of <a -href="http://en.wikipedia.org/wiki/Stack-smashing_protection">buffer overflow -protection</a>. llvm-gcc supports this with the <tt>-fstack-protector</tt> -command line option (just like GCC). In LLVM IR, you can request code -generation for stack canaries with function attributes. -</li> +<li>New <a href="#compiler-rt">compiler-rt</a>, <A href="#klee">KLEE</a> + and <a href="#mc">machine code toolkit</a> sub-projects.</li> +<li>Debug information now includes line numbers when optimizations are enabled. + This allows statistical sampling tools like OProfile and Shark to map + samples back to source lines.</li> +<li>LLVM now includes new experimental backends to support the MSP430, SystemZ + and BlackFin architectures.</li> +<li>LLVM supports a new <a href="GoldPlugin.html">Gold Linker Plugin</a> which + enables support for <a href="LinkTimeOptimization.html">transparent + link-time optimization</a> on ELF targets when used with the Gold binutils + linker.</li> +<li>LLVM now supports doing optimization and code generation on multiple + threads. Please see the <a href="ProgrammersManual.html#threading">LLVM + Programmer's Manual</a> for more information.</li> +<li>LLVM now has experimental support for <a + href="http://nondot.org/~sabre/LLVMNotes/EmbeddedMetadata.txt">embedded + metadata</a> in LLVM IR, though the implementation is not guaranteed to be + final and the .bc file format may change in future releases. Debug info + does not yet use this format in LLVM 2.6.</li> </ul> </div> - <!--=========================================================================--> <div class="doc_subsection"> <a name="coreimprovements">LLVM IR and Core Improvements</a> </div> <div class="doc_text"> -<p>LLVM IR has several new features that are used by our existing front-ends and -can be useful if you are writing a front-end for LLVM:</p> +<p>LLVM IR has several new features for better support of new targets and that +expose new optimization opportunities:</p> <ul> -<li>The <a href="LangRef.html#i_shufflevector">shufflevector</a> instruction -has been generalized to allow different shuffle mask width than its input -vectors. This allows you to use shufflevector to combine two -"<4 x float>" vectors into a "<8 x float>" for example.</li> - -<li>LLVM IR now supports new intrinsics for computing and acting on <a -href="LangRef.html#int_overflow">overflow of integer operations</a>. This allows -efficient code generation for languages that must trap or throw an exception on -overflow. While these intrinsics work on all targets, they only generate -efficient code on X86 so far.</li> - -<li>LLVM IR now supports a new <a href="LangRef.html#linkage">private -linkage</a> type to produce labels that are stripped by the assembler before it -produces a .o file (thus they are invisible to the linker).</li> - -<li>LLVM IR supports two new attributes for better alias analysis. The <a -href="LangRef.html#paramattrs">noalias</a> attribute can now be used on the -return value of a function to indicate that it returns new memory (e.g. -'malloc', 'calloc', etc). -The new <a href="LangRef.html#paramattrs">nocapture</a> attribute can be used -on pointer arguments to indicate that the function does not return the pointer, -store it in an object that outlives the call, or let the value of the pointer -escape from the function in any other way. -Note that it is the pointer itself that must not escape, not the value it -points to: loading a value out of the pointer is perfectly fine. -Many standard library functions (e.g. 'strlen', 'memcpy') have this property. -<!-- The simplifylibcalls pass applies these attributes to standard libc functions. --> -</li> - -<li>The parser for ".ll" files in lib/AsmParser is now completely rewritten as a -recursive descent parser. This parser produces better error messages (including -caret diagnostics), is less fragile (less likely to crash on strange things), -does not leak memory, is more efficient, and eliminates LLVM's last use of the -'bison' tool.</li> - -<li>Debug information representation and manipulation internals have been - consolidated to use a new set of classes in - <tt>llvm/Analysis/DebugInfo.h</tt>. These routines are more - efficient, robust, and extensible and replace the older mechanisms. - llvm-gcc, clang, and the code generator now use them to create and process - debug information.</li> - +<li>The <a href="LangRef.html#i_add">add</a>, <a + href="LangRef.html#i_sub">sub</a> and <a href="LangRef.html#i_mul">mul</a> + instructions have been split into integer and floating point versions (like + divide and remainder), introducing new <a + href="LangRef.html#i_fadd">fadd</a>, <a href="LangRef.html#i_fsub">fsub</a>, + and <a href="LangRef.html#i_fmul">fmul</a> instructions.</li> +<li>The <a href="LangRef.html#i_add">add</a>, <a + href="LangRef.html#i_sub">sub</a> and <a href="LangRef.html#i_mul">mul</a> + instructions now support optional "nsw" and "nuw" bits which indicate that + the operation is guaranteed to not overflow (in the signed or + unsigned case, respectively). This gives the optimizer more information and + can be used for things like C signed integer values, which are undefined on + overflow.</li> +<li>The <a href="LangRef.html#i_sdiv">sdiv</a> instruction now supports an + optional "exact" flag which indicates that the result of the division is + guaranteed to have a remainder of zero. This is useful for optimizing pointer + subtraction in C.</li> +<li>The <a href="LangRef.html#i_getelementptr">getelementptr</a> instruction now + supports arbitrary integer index values for array/pointer indices. This + allows for better code generation on 16-bit pointer targets like PIC16.</li> +<li>The <a href="LangRef.html#i_getelementptr">getelementptr</a> instruction now + supports an "inbounds" optimization hint that tells the optimizer that the + pointer is guaranteed to be within its allocated object.</li> +<li>LLVM now support a series of new linkage types for global values which allow + for better optimization and new capabilities: + <ul> + <li><a href="LangRef.html#linkage_linkonce">linkonce_odr</a> and + <a href="LangRef.html#linkage_weak">weak_odr</a> have the same linkage + semantics as the non-"odr" linkage types. The difference is that these + linkage types indicate that all definitions of the specified function + are guaranteed to have the same semantics. This allows inlining + templates functions in C++ but not inlining weak functions in C, + which previously both got the same linkage type.</li> + <li><a href="LangRef.html#linkage_available_externally">available_externally + </a> is a new linkage type that gives the optimizer visibility into the + definition of a function (allowing inlining and side effect analysis) + but that does not cause code to be generated. This allows better + optimization of "GNU inline" functions, extern templates, etc.</li> + <li><a href="LangRef.html#linkage_linker_private">linker_private</a> is a + new linkage type (which is only useful on Mac OS X) that is used for + some metadata generation and other obscure things.</li> + </ul></li> +<li>Finally, target-specific intrinsics can now return multiple values, which + is useful for modeling target operations with multiple results.</li> </ul> </div> @@ -405,27 +569,53 @@ does not leak memory, is more efficient, and eliminates LLVM's last use of the <div class="doc_text"> -<p>In addition to a large array of bug fixes and minor performance tweaks, this +<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>The loop optimizer now improves floating point induction variables in -several ways, including adding shadow induction variables to avoid -"integer <-> floating point" conversions in loops when safe.</li> +<li>The <a href="Passes.html#scalarrepl">Scalar Replacement of Aggregates</a> + pass has many improvements that allow it to better promote vector unions, + variables which are memset, and much more strange code that can happen to + do bitfield accesses to register operations. An interesting change is that + it now produces "unusual" integer sizes (like i1704) in some cases and lets + other optimizers clean things up.</li> +<li>The <a href="Passes.html#loop-reduce">Loop Strength Reduction</a> pass now + promotes small integer induction variables to 64-bit on 64-bit targets, + which provides a major performance boost for much numerical code. It also + promotes shorts to int on 32-bit hosts, etc. LSR now also analyzes pointer + expressions (e.g. getelementptrs), as well as integers.</li> +<li>The <a href="Passes.html#gvn">GVN</a> pass now eliminates partial + redundancies of loads in simple cases.</li> +<li>The <a href="Passes.html#inline">Inliner</a> now reuses stack space when + inlining similar arrays from multiple callees into one caller.</li> +<li>LLVM includes a new experimental Static Single Information (SSI) + construction pass.</li> -<li>The "-mem2reg" pass is now much faster on code with large basic blocks.</li> +</ul> + +</div> -<li>The "-jump-threading" pass is more powerful: it is iterative - and handles threading based on values with fully and partially redundant - loads.</li> -<li>The "-memdep" memory dependence analysis pass (used by GVN and memcpyopt) is - both faster and more aggressive.</li> +<!--=========================================================================--> +<div class="doc_subsection"> +<a name="executionengine">Interpreter and JIT Improvements</a> +</div> -<li>The "-scalarrepl" scalar replacement of aggregates pass is more aggressive - about promoting unions to registers.</li> +<div class="doc_text"> +<ul> +<li>LLVM has a new "EngineBuilder" class which makes it more obvious how to + set up and configure an ExecutionEngine (a JIT or interpreter).</li> +<li>The JIT now supports generating more than 16M of code.</li> +<li>When configured with <tt>--with-oprofile</tt>, the JIT can now inform + OProfile about JIT'd code, allowing OProfile to get line number and function + name information for JIT'd functions.</li> +<li>When "libffi" is available, the LLVM interpreter now uses it, which supports + calling almost arbitrary external (natively compiled) functions.</li> +<li>Clients of the JIT can now register a 'JITEventListener' object to receive + callbacks when the JIT emits or frees machine code. The OProfile support + uses this mechanism.</li> </ul> </div> @@ -442,33 +632,55 @@ infrastructure, which allows us to implement more aggressive algorithms and make it run faster:</p> <ul> -<li>The <a href="WritingAnLLVMBackend.html">Writing an LLVM Compiler -Backend</a> document has been greatly expanded and is substantially more -complete.</li> - -<li>The SelectionDAG type legalization logic has been completely rewritten, is -now more powerful (it supports arbitrary precision integer types for example), -and is more correct in several corner cases. The type legalizer converts -operations on types that are not natively supported by the target machine into -equivalent code sequences that only use natively supported types. The old type -legalizer is still available (for now) and will be used if -<tt>-disable-legalize-types</tt> is passed to the code generator. -</li> -<li>The code generator now supports widening illegal vectors to larger legal -ones (for example, converting operations on <3 x float> to work on -<4 x float>) which is very important for common graphics -applications.</li> - -<li>The assembly printers for each target are now split out into their own -libraries that are separate from the main code generation logic. This reduces -the code size of JIT compilers by not requiring them to be linked in.</li> - -<li>The 'fast' instruction selection path (used at -O0 and for fast JIT - compilers) now supports accelerating codegen for code that uses exception - handling constructs.</li> - -<li>The optional PBQP register allocator now supports register coalescing.</li> +<li>The <tt>llc -asm-verbose</tt> option (exposed from llvm-gcc as <tt>-dA</tt> + and clang as <tt>-fverbose-asm</tt> or <tt>-dA</tt>) now adds a lot of + useful information in comments to + the generated .s file. This information includes location information (if + built with <tt>-g</tt>) and loop nest information.</li> +<li>The code generator now supports a new MachineVerifier pass which is useful + for finding bugs in targets and codegen passes.</li> +<li>The Machine LICM is now enabled by default. It hoists instructions out of + loops (such as constant pool loads, loads from read-only stubs, vector + constant synthesization code, etc.) and is currently configured to only do + so when the hoisted operation can be rematerialized.</li> +<li>The Machine Sinking pass is now enabled by default. This pass moves + side-effect free operations down the CFG so that they are executed on fewer + paths through a function.</li> +<li>The code generator now performs "stack slot coloring" of register spills, + which allows spill slots to be reused. This leads to smaller stack frames + in cases where there are lots of register spills.</li> +<li>The register allocator has many improvements to take better advantage of + commutable operations, various spiller peephole optimizations, and can now + coalesce cross-register-class copies.</li> +<li>Tblgen now supports multiclass inheritance and a number of new string and + list operations like <tt>!(subst)</tt>, <tt>!(foreach)</tt>, <tt>!car</tt>, + <tt>!cdr</tt>, <tt>!null</tt>, <tt>!if</tt>, <tt>!cast</tt>. + These make the .td files more expressive and allow more aggressive factoring + of duplication across instruction patterns.</li> +<li>Target-specific intrinsics can now be added without having to hack VMCore to + add them. This makes it easier to maintain out-of-tree targets.</li> +<li>The instruction selector is better at propagating information about values + (such as whether they are sign/zero extended etc.) across basic block + boundaries.</li> +<li>The SelectionDAG datastructure has new nodes for representing buildvector + and <a href="http://llvm.org/PR2957">vector shuffle</a> operations. This + makes operations and pattern matching more efficient and easier to get + right.</li> +<li>The Prolog/Epilog Insertion Pass now has experimental support for performing + the "shrink wrapping" optimization, which moves spills and reloads around in + the CFG to avoid doing saves on paths that don't need them.</li> +<li>LLVM includes new experimental support for writing ELF .o files directly + from the compiler. It works well for many simple C testcases, but doesn't + support exception handling, debug info, inline assembly, etc.</li> +<li>Targets can now specify register allocation hints through + <tt>MachineRegisterInfo::setRegAllocationHint</tt>. A regalloc hint consists + of hint type and physical register number. A hint type of zero specifies a + register allocation preference. Other hint type values are target specific + which are resolved by <tt>TargetRegisterInfo::ResolveRegAllocHint</tt>. An + example is the ARM target which uses register hints to request that the + register allocator provide an even / odd register pair to two virtual + registers.</li> </ul> </div> @@ -482,37 +694,33 @@ the code size of JIT compilers by not requiring them to be linked in.</li> </p> <ul> -<li>The <tt><a href="LangRef.html#int_returnaddress">llvm.returnaddress</a></tt> -intrinsic (which is used to implement <tt>__builtin_return_address</tt>) now -supports non-zero stack depths on X86.</li> - -<li>The X86 backend now supports code generation of vector shift operations -using SSE instructions.</li> - -<li>X86-64 code generation now takes advantage of red zone, unless the -<tt>-mno-red-zone</tt> option is specified.</li> - -<li>The X86 backend now supports using address space #256 in LLVM IR as a way of -performing memory references off the GS segment register. This allows a -front-end to take advantage of very low-level programming techniques when -targeting X86 CPUs. See <tt>test/CodeGen/X86/movgs.ll</tt> for a simple -example.</li> - -<li>The X86 backend now supports a <tt>-disable-mmx</tt> command line option to - prevent use of MMX even on chips that support it. This is important for cases - where code does not contain the proper <tt>llvm.x86.mmx.emms</tt> - intrinsics.</li> - -<li>The X86 JIT now detects the new Intel <a - href="http://en.wikipedia.org/wiki/Intel_Core_i7">Core i7</a> and <a - href="http://en.wikipedia.org/wiki/Intel_Atom">Atom</a> chips and - auto-configures itself appropriately for the features of these chips.</li> - -<li>The JIT now supports exception handling constructs on Linux/X86-64 and - Darwin/x86-64.</li> -<li>The JIT supports Thread Local Storage (TLS) on Linux/X86-32 but not yet on - X86-64.</li> +<li>SSE 4.2 builtins are now supported.</li> +<li>GCC-compatible soft float modes are now supported, which are typically used + by OS kernels.</li> +<li>X86-64 now models implicit zero extensions better, which allows the code + generator to remove a lot of redundant zexts. It also models the 8-bit "H" + registers as subregs, which allows them to be used in some tricky + situations.</li> +<li>X86-64 now supports the "local exec" and "initial exec" thread local storage + model.</li> +<li>The vector forms of the <a href="LangRef.html#i_icmp">icmp</a> and <a + href="LangRef.html#i_fcmp">fcmp</a> instructions now select to efficient + SSE operations.</li> +<li>Support for the win64 calling conventions have improved. The primary + missing feature is support for varargs function definitions. It seems to + work well for many win64 JIT purposes.</li> +<li>The X86 backend has preliminary support for <a + href="CodeGenerator.html#x86_memory">mapping address spaces to segment + register references</a>. This allows you to write GS or FS relative memory + accesses directly in LLVM IR for cases where you know exactly what you're + doing (such as in an OS kernel). There are some known problems with this + support, but it works in simple cases.</li> +<li>The X86 code generator has been refactored to move all global variable + reference logic to one place + (<tt>X86Subtarget::ClassifyGlobalReference</tt>) which + makes it easier to reason about.</li> + </ul> </div> @@ -527,70 +735,156 @@ example.</li> </p> <ul> -<li>Both direct and indirect load/stores work now.</li> -<li>Logical, bitwise and conditional operations now work for integer data -types.</li> -<li>Function calls involving basic types work now.</li> -<li>Support for integer arrays.</li> -<li>The compiler can now emit libcalls for operations not supported by m/c -instructions.</li> -<li>Support for both data and ROM address spaces.</li> +<li>Support for floating-point, indirect function calls, and + passing/returning aggregate types to functions. +<li>The code generator is able to generate debug info into output COFF files. +<li>Support for placing an object into a specific section or at a specific + address in memory.</li> </ul> <p>Things not yet supported:</p> <ul> -<li>Floating point.</li> -<li>Passing/returning aggregate types to and from functions.</li> <li>Variable arguments.</li> -<li>Indirect function calls.</li> <li>Interrupts/programs.</li> -<li>Debug info.</li> </ul> </div> +<!--=========================================================================--> +<div class="doc_subsection"> +<a name="ARM">ARM Target Improvements</a> +</div> + +<div class="doc_text"> +<p>New features of the ARM target include: +</p> + +<ul> + +<li>Preliminary support for processors, such as the Cortex-A8 and Cortex-A9, +that implement version v7-A of the ARM architecture. The ARM backend now +supports both the Thumb2 and Advanced SIMD (Neon) instruction sets.</li> + +<li>The AAPCS-VFP "hard float" calling conventions are also supported with the +<tt>-float-abi=hard</tt> flag.</li> + +<li>The ARM calling convention code is now tblgen generated instead of resorting + to C++ code.</li> +</ul> + +<p>These features are still somewhat experimental +and subject to change. The Neon intrinsics, in particular, may change in future +releases of LLVM. ARMv7 support has progressed a lot on top of tree since 2.6 +branched.</p> + + +</div> <!--=========================================================================--> <div class="doc_subsection"> -<a name="llvmc">Improvements in LLVMC</a> +<a name="OtherTarget">Other Target Specific Improvements</a> </div> <div class="doc_text"> -<p>New features include:</p> +<p>New features of other targets include: +</p> <ul> -<li>Beginning with LLVM 2.5, <tt>llvmc2</tt> is known as - just <tt>llvmc</tt>. The old <tt>llvmc</tt> driver was removed.</li> +<li>Mips now supports O32 Calling Convention.</li> +<li>Many improvements to the 32-bit PowerPC SVR4 ABI (used on powerpc-linux) + support, lots of bugs fixed.</li> +<li>Added support for the 64-bit PowerPC SVR4 ABI (used on powerpc64-linux). + Needs more testing.</li> +</ul> + +</div> + +<!--=========================================================================--> +<div class="doc_subsection"> +<a name="newapis">New Useful APIs</a> +</div> -<li>The Clang plugin was substantially improved and is now enabled - by default. The command <tt>llvmc --clang</tt> can be now used as a - synonym to <tt>ccc</tt>.</li> +<div class="doc_text"> -<li>There is now a <tt>--check-graph</tt> option, which is supposed to catch - common errors like multiple default edges, mismatched output/input language - names and cycles. In general, these checks can't be done at compile-time - because of the need to support plugins.</li> +<p>This release includes a number of new APIs that are used internally, which + may also be useful for external clients. +</p> -<li>Plugins are now more flexible and can refer to compilation graph nodes and - options defined in other plugins. To manage dependencies, a priority-sorting - mechanism was introduced. This change affects the TableGen file syntax. See the - documentation for details.</li> +<ul> +<li>New <a href="http://llvm.org/doxygen/PrettyStackTrace_8h-source.html"> + <tt>PrettyStackTrace</tt> class</a> allows crashes of llvm tools (and applications + that integrate them) to provide more detailed indication of what the + compiler was doing at the time of the crash (e.g. running a pass). + At the top level for each LLVM tool, it includes the command line arguments. + </li> +<li>New <a href="http://llvm.org/doxygen/StringRef_8h-source.html">StringRef</a> + and <a href="http://llvm.org/doxygen/Twine_8h-source.html">Twine</a> classes + make operations on character ranges and + string concatenation to be more efficient. <tt>StringRef</tt> is just a <tt>const + char*</tt> with a length, <tt>Twine</tt> is a light-weight rope.</li> +<li>LLVM has new <tt>WeakVH</tt>, <tt>AssertingVH</tt> and <tt>CallbackVH</tt> + classes, which make it easier to write LLVM IR transformations. <tt>WeakVH</tt> + is automatically drops to null when the referenced <tt>Value</tt> is deleted, + and is updated across a <tt>replaceAllUsesWith</tt> operation. + <tt>AssertingVH</tt> aborts the program if the + referenced value is destroyed while it is being referenced. <tt>CallbackVH</tt> + is a customizable class for handling value references. See <a + href="http://llvm.org/doxygen/ValueHandle_8h-source.html">ValueHandle.h</a> + for more information.</li> +<li>The new '<a href="http://llvm.org/doxygen/Triple_8h-source.html">Triple + </a>' class centralizes a lot of logic that reasons about target + triples.</li> +<li>The new '<a href="http://llvm.org/doxygen/ErrorHandling_8h-source.html"> + llvm_report_error()</a>' set of APIs allows tools to embed the LLVM + optimizer and backend and recover from previously unrecoverable errors.</li> +<li>LLVM has new abstractions for <a + href="http://llvm.org/doxygen/Atomic_8h-source.html">atomic operations</a> + and <a href="http://llvm.org/doxygen/RWMutex_8h-source.html">reader/writer + locks</a>.</li> +<li>LLVM has new <a href="http://llvm.org/doxygen/SourceMgr_8h-source.html"> + <tt>SourceMgr</tt> and <tt>SMLoc</tt> classes</a> which implement caret + diagnostics and basic include stack processing for simple parsers. It is + used by tablegen, llvm-mc, the .ll parser and FileCheck.</li> +</ul> -<li>Hooks can now be provided with arguments. The syntax is "<tt>$CALL(MyHook, - 'Arg1', 'Arg2', 'Arg3')</tt>".</li> -<li>A new option type: multi-valued option, for options that take more than one - argument (for example, "<tt>-foo a b c</tt>").</li> +</div> -<li>New option properties: '<tt>one_or_more</tt>', '<tt>zero_or_more</tt>', -'<tt>hidden</tt>' and '<tt>really_hidden</tt>'.</li> +<!--=========================================================================--> +<div class="doc_subsection"> +<a name="otherimprovements">Other Improvements and New Features</a> +</div> -<li>The '<tt>case</tt>' expression gained an '<tt>error</tt>' action and - an '<tt>empty</tt>' test (equivalent to "<tt>(not (not_empty ...))</tt>").</li> +<div class="doc_text"> +<p>Other miscellaneous features include:</p> -<li>Documentation now looks more consistent to the rest of the LLVM - docs. There is also a man page now.</li> +<ul> +<li>LLVM now includes a new internal '<a + href="http://llvm.org/cmds/FileCheck.html">FileCheck</a>' tool which allows + writing much more accurate regression tests that run faster. Please see the + <a href="TestingGuide.html#FileCheck">FileCheck section of the Testing + Guide</a> for more information.</li> +<li>LLVM profile information support has been significantly improved to produce +correct use counts, and has support for edge profiling with reduced runtime +overhead. Combined, the generated profile information is both more correct and +imposes about half as much overhead (2.6. from 12% to 6% overhead on SPEC +CPU2000).</li> +<li>The C bindings (in the llvm/include/llvm-c directory) include many newly + supported APIs.</li> +<li>LLVM 2.6 includes a brand new experimental LLVM bindings to the Ada2005 + programming language.</li> + +<li>The LLVMC driver has several new features: + <ul> + <li>Dynamic plugins now work on Windows.</li> + <li>New option property: init. Makes possible to provide default values for + options defined in plugins (interface to <tt>cl::init</tt>).</li> + <li>New example: Skeleton, shows how to create a standalone LLVMC-based + driver.</li> + <li>New example: mcc16, a driver for the PIC16 toolchain.</li> + </ul> +</li> </ul> @@ -605,13 +899,24 @@ instructions.</li> <div class="doc_text"> <p>If you're already an LLVM user or developer with out-of-tree changes based -on LLVM 2.4, this section lists some "gotchas" that you may run into upgrading +on LLVM 2.5, this section lists some "gotchas" that you may run into upgrading from the previous release.</p> <ul> - -<li>llvm-gcc defaults to <tt>-fno-math-errno</tt> on all X86 targets.</li> - +<li>The Itanium (IA64) backend has been removed. It was not actively supported + and had bitrotted.</li> +<li>The BigBlock register allocator has been removed, it had also bitrotted.</li> +<li>The C Backend (<tt>-march=c</tt>) is no longer considered part of the LLVM release +criteria. We still want it to work, but no one is maintaining it and it lacks +support for arbitrary precision integers and other important IR features.</li> + +<li>All LLVM tools now default to overwriting their output file, behaving more + like standard unix tools. Previously, this only happened with the '<tt>-f</tt>' + option.</li> +<li>LLVM build now builds all libraries as .a files instead of some + libraries as relinked .o files. This requires some APIs like + InitializeAllTargets.h. + </li> </ul> @@ -619,8 +924,82 @@ from the previous release.</p> API changes are:</p> <ul> -<li>Some deprecated interfaces to create <tt>Instruction</tt> subclasses, that - were spelled with lower case "create," have been removed.</li> +<li>All uses of <tt>hash_set</tt> and <tt>hash_map</tt> have been removed from + the LLVM tree and the wrapper headers have been removed.</li> +<li>The llvm/Streams.h and <tt>DOUT</tt> member of Debug.h have been removed. The + <tt>llvm::Ostream</tt> class has been completely removed and replaced with + uses of <tt>raw_ostream</tt>.</li> +<li>LLVM's global uniquing tables for <tt>Type</tt>s and <tt>Constant</tt>s have + been privatized into members of an <tt>LLVMContext</tt>. A number of APIs + now take an <tt>LLVMContext</tt> as a parameter. To smooth the transition + for clients that will only ever use a single context, the new + <tt>getGlobalContext()</tt> API can be used to access a default global + context which can be passed in any and all cases where a context is + required. +<li>The <tt>getABITypeSize</tt> methods are now called <tt>getAllocSize</tt>.</li> +<li>The <tt>Add</tt>, <tt>Sub</tt> and <tt>Mul</tt> operators are no longer + overloaded for floating-point types. Floating-point addition, subtraction + and multiplication are now represented with new operators <tt>FAdd</tt>, + <tt>FSub</tt> and <tt>FMul</tt>. In the <tt>IRBuilder</tt> API, + <tt>CreateAdd</tt>, <tt>CreateSub</tt>, <tt>CreateMul</tt> and + <tt>CreateNeg</tt> should only be used for integer arithmetic now; + <tt>CreateFAdd</tt>, <tt>CreateFSub</tt>, <tt>CreateFMul</tt> and + <tt>CreateFNeg</tt> should now be used for floating-point arithmetic.</li> +<li>The <tt>DynamicLibrary</tt> class can no longer be constructed, its functionality has + moved to static member functions.</li> +<li><tt>raw_fd_ostream</tt>'s constructor for opening a given filename now + takes an extra <tt>Force</tt> argument. If <tt>Force</tt> is set to + <tt>false</tt>, an error will be reported if a file with the given name + already exists. If <tt>Force</tt> is set to <tt>true</tt>, the file will + be silently truncated (which is the behavior before this flag was + added).</li> +<li><tt>SCEVHandle</tt> no longer exists, because reference counting is no + longer done for <tt>SCEV*</tt> objects, instead <tt>const SCEV*</tt> + should be used.</li> + +<li>Many APIs, notably <tt>llvm::Value</tt>, now use the <tt>StringRef</tt> +and <tt>Twine</tt> classes instead of passing <tt>const char*</tt> +or <tt>std::string</tt>, as described in +the <a href="ProgrammersManual.html#string_apis">Programmer's Manual</a>. Most +clients should be unaffected by this transition, unless they are used to +<tt>Value::getName()</tt> returning a string. Here are some tips on updating to +2.6: + <ul> + <li><tt>getNameStr()</tt> is still available, and matches the old + behavior. Replacing <tt>getName()</tt> calls with this is an safe option, + although more efficient alternatives are now possible.</li> + + <li>If you were just relying on <tt>getName()</tt> being able to be sent to + a <tt>std::ostream</tt>, consider migrating + to <tt>llvm::raw_ostream</tt>.</li> + + <li>If you were using <tt>getName().c_str()</tt> to get a <tt>const + char*</tt> pointer to the name, you can use <tt>getName().data()</tt>. + Note that this string (as before), may not be the entire name if the + name contains embedded null characters.</li> + + <li>If you were using <tt>operator +</tt> on the result of <tt>getName()</tt> and + treating the result as an <tt>std::string</tt>, you can either + use <tt>Twine::str</tt> to get the result as an <tt>std::string</tt>, or + could move to a <tt>Twine</tt> based design.</li> + + <li><tt>isName()</tt> should be replaced with comparison + against <tt>getName()</tt> (this is now efficient). + </ul> +</li> + +<li>The registration interfaces for backend Targets has changed (what was +previously <tt>TargetMachineRegistry</tt>). For backend authors, see the <a +href="WritingAnLLVMBackend.html#TargetRegistration">Writing An LLVM Backend</a> +guide. For clients, the notable API changes are: + <ul> + <li><tt>TargetMachineRegistry</tt> has been renamed + to <tt>TargetRegistry</tt>.</li> + + <li>Clients should move to using the <tt>TargetRegistry::lookupTarget()</tt> + function to find targets.</li> + </ul> +</li> </ul> </div> @@ -639,15 +1018,15 @@ API changes are:</p> <ul> <li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat -Linux, Fedora Core and FreeBSD (and probably other unix-like systems).</li> + Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like + systems).</li> <li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit -and 64-bit modes.</li> + and 64-bit modes.</li> <li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li> <li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited support is available for native builds with Visual C++).</li> -<li>Sun UltraSPARC workstations running Solaris 10.</li> +<li>Sun x86 and AMD64 machines running Solaris 10, OpenSolaris 0906.</li> <li>Alpha-based machines running Debian GNU/Linux.</li> -<li>Itanium-based (IA64) machines running Linux and HP-UX.</li> </ul> <p>The core LLVM infrastructure uses GNU autoconf to adapt itself @@ -670,6 +1049,21 @@ 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> +<ul> +<li>The llvm-gcc bootstrap will fail with some versions of binutils (e.g. 2.15) + with a message of "<tt><a href="http://llvm.org/PR5004">Error: can not do 8 + byte pc-relative relocation</a></tt>" when building C++ code. We intend to + fix this on mainline, but a workaround for 2.6 is to upgrade to binutils + 2.17 or later.</li> + +<li>LLVM will not correctly compile on Solaris and/or OpenSolaris +using the stock GCC 3.x.x series 'out the box', +See: <a href="#brokengcc">Broken versions of GCC and other tools</a>. +However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a> +for x86/x86-64 has been made available from the third party AuroraUX Project +that has been meticulously tested for bootstrapping LLVM & Clang.</li> +</ul> + </div> <!-- ======================================================================= --> @@ -687,9 +1081,11 @@ components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p> <ul> -<li>The MSIL, IA64, Alpha, SPU, MIPS, and PIC16 backends are experimental.</li> +<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430 and SystemZ backends are + experimental.</li> <li>The <tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only - supported value for this option.</li> + supported value for this option. The ELF writer is experimental.</li> +<li>The implementation of Andersen's Alias Analysis has many known bugs.</li> </ul> </div> @@ -744,14 +1140,14 @@ compilation, and lacks support for debug information.</li> <div class="doc_text"> <ul> +<li>Support for the Advanced SIMD (Neon) instruction set is still incomplete +and not well tested. Some features may not work at all, and the code quality +may be poor in some cases.</li> <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> -<li>There is a bug in QEMU-ARM (<= 0.9.0) which causes it to incorrectly - execute -programs compiled with LLVM. Please use more recent versions of QEMU.</li> </ul> </div> @@ -778,7 +1174,6 @@ programs compiled with LLVM. Please use more recent versions of QEMU.</li> <div class="doc_text"> <ul> -<li>The O32 ABI is not fully supported.</li> <li>64-bit MIPS targets are not supported yet.</li> </ul> @@ -801,21 +1196,6 @@ appropriate nops inserted to ensure restartability.</li> <!-- ======================================================================= --> <div class="doc_subsection"> - <a name="ia64-be">Known problems with the IA64 back-end</a> -</div> - -<div class="doc_text"> - -<ul> -<li>The Itanium backend is highly experimental and has a number of known - issues. We are looking for a maintainer for the Itanium backend. If you - are interested, please contact the LLVMdev mailing list.</li> -</ul> - -</div> - -<!-- ======================================================================= --> -<div class="doc_subsection"> <a name="c-be">Known problems with the C back-end</a> </div> @@ -841,10 +1221,6 @@ appropriate nops inserted to ensure restartability.</li> <div class="doc_text"> -<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time -Optimization</a> on most platforms "out-of-the-box". Please inquire on the -LLVMdev mailing list if you are interested.</p> - <p>The only major language feature of GCC not supported by llvm-gcc is the <tt>__builtin_apply</tt> family of builtins. However, some extensions are only supported on some targets. For example, trampolines are only @@ -882,7 +1258,8 @@ itself, Qt, Mozilla, etc.</p> <div class="doc_text"> <ul> <li>Fortran support generally works, but there are still several unresolved bugs - in Bugzilla. Please see the tools/gfortran component for details.</li> + in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the + tools/gfortran component for details.</li> </ul> </div> @@ -902,16 +1279,16 @@ which does support trampolines.</li> <li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>. This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style exception handling, which is used internally by the compiler. -Workaround: configure with --disable-bootstrap.</li> +Workaround: configure with <tt>--disable-bootstrap</tt>.</li> <li>The c380004, <a href="http://llvm.org/PR2010">c393010</a> and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail (c380004 also fails with gcc-4.2 mainline). If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a> causes the compiler to go into an infinite loop, using up all system memory.</li> <li>Some GCC specific Ada tests continue to crash the compiler.</li> -<li>The -E binder option (exception backtraces) +<li>The <tt>-E</tt> binder option (exception backtraces) <a href="http://llvm.org/PR1982">does not work</a> and will result in programs -crashing if an exception is raised. Workaround: do not use -E.</li> +crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li> <li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start or finish at a non-byte offset</a> in a record. Workaround: do not pack records or use representation clauses that result in a field of a non-discrete type @@ -925,6 +1302,20 @@ ignored</a>.</li> </ul> </div> +<!-- ======================================================================= --> +<div class="doc_subsection"> + <a name="ocaml-bindings">Known problems with the O'Caml bindings</a> +</div> + +<div class="doc_text"> + +<p>The <tt>Llvm.Linkage</tt> module is broken, and has incorrect values. Only +<tt>Llvm.Linkage.External</tt>, <tt>Llvm.Linkage.Available_externally</tt>, and +<tt>Llvm.Linkage.Link_once</tt> will be correct. If you need any of the other linkage +modes, you'll have to write an external C library in order to expose the +functionality. This has been fixed in the trunk.</p> +</div> + <!-- *********************************************************************** --> <div class="doc_section"> <a name="additionalinfo">Additional Information</a> |