diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/docs/GettingStarted.html | 1 | ||||
| -rw-r--r-- | llvm/docs/ReleaseNotes.html | 745 |
2 files changed, 512 insertions, 234 deletions
diff --git a/llvm/docs/GettingStarted.html b/llvm/docs/GettingStarted.html index 8bb1ac41e4fd..05169f82123c 100644 --- a/llvm/docs/GettingStarted.html +++ b/llvm/docs/GettingStarted.html @@ -726,6 +726,7 @@ revision), you can checkout it from the '<tt>tags</tt>' directory (instead of subdirectories of the '<tt>tags</tt>' directory:</p> <ul> +<li>Release 2.7: <b>RELEASE_27</b></li> <li>Release 2.6: <b>RELEASE_26</b></li> <li>Release 2.5: <b>RELEASE_25</b></li> <li>Release 2.4: <b>RELEASE_24</b></li> diff --git a/llvm/docs/ReleaseNotes.html b/llvm/docs/ReleaseNotes.html index 3c350c7c5231..19b92f1d0376 100644 --- a/llvm/docs/ReleaseNotes.html +++ b/llvm/docs/ReleaseNotes.html @@ -10,6 +10,9 @@ <div class="doc_title">LLVM 2.7 Release Notes</div> +<img align=right src="http://llvm.org/img/DragonSmall.png" + width="136" height="136" alt="LLVM Dragon Logo"> + <ol> <li><a href="#intro">Introduction</a></li> <li><a href="#subproj">Sub-project Status Update</a></li> @@ -25,11 +28,12 @@ <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 2.7 +<!-- +<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.8 release.<br> You may prefer the -<a href="http://llvm.org/releases/2.6/docs/ReleaseNotes.html">LLVM 2.6 -Release Notes</a>.</h1> +<a href="http://llvm.org/releases/2.6/docs/ReleaseNotes.html">LLVM 2.7 +Release Notes</a>.</h1>--> <!-- *********************************************************************** --> <div class="doc_section"> @@ -48,8 +52,8 @@ 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://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's Mailing -List</a> is a good place to send them.</p> +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 @@ -64,22 +68,17 @@ 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. - ABCD, SCCVN, GEPSplitterPass + ABCD, GEPSplitterPass MSIL backend? + lib/Transforms/Utils/SSI.cpp -> ABCD depends on it. --> <!-- Features that need text if they're finished for 2.7: - gcc plugin. + combiner-aa? strong phi elim - variable debug info for optimized code - postalloc scheduler: anti dependence breaking, hazard recognizer? - metadata + llvm.dbg.value: variable debug info for optimized code 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: @@ -88,8 +87,7 @@ Almost dead code. compiler_rt KLEE web page at klee.llvm.org Many new papers added to /pubs/ - Mention gcc plugin. - + Mention gcc plugin. --> <!-- *********************************************************************** --> @@ -117,12 +115,49 @@ development. Here we include updates on these subprojects. <div class="doc_text"> -<p>The <a href="http://clang.llvm.org/">Clang project</a> is ...</p> +<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 and Objective-C on x86 (32- and 64-bit).</p> <p>In the LLVM 2.7 time-frame, the Clang team has made many improvements:</p> <ul> -<li>...</li> + +<li>C++ Support: Clang is now capable of self-hosting! While still +alpha-quality, Clang's C++ support has matured enough to build LLVM and Clang, +and C++ is now enabled by default. See the <a +href="http://clang.llvm.org/cxx_compatibility.html">Clang C++ compatibility +page</a> for common C++ migration issues.</li> + +<li>Objective-C: Clang now includes experimental support for an updated +Objective-C ABI on non-Darwin platforms. This includes support for non-fragile +instance variables and accelerated proxies, as well as greater potential for +future optimisations. The new ABI is used when compiling with the +-fobjc-nonfragile-abi and -fgnu-runtime options. Code compiled with these +options may be mixed with code compiled with GCC or clang using the old GNU ABI, +but requires the libobjc2 runtime from the GNUstep project.</li> + +<li>New warnings: Clang contains a number of new warnings, including +control-flow warnings (unreachable code, missing return statements in a +non-<code>void</code> function, etc.), sign-comparison warnings, and improved +format-string warnings.</li> + +<li>CIndex API and Python bindings: Clang now includes a C API as part of the +CIndex library. Although we may make some changes to the API in the future, it +is intended to be stable and has been designed for use by external projects. See +the Clang +doxygen <a href="http://clang.llvm.org/doxygen/group__CINDEX.html">CIndex</a> +documentation for more details. The CIndex API also includes a preliminary +set of Python bindings.</li> + +<li>ARM Support: Clang now has ABI support for both the Darwin and Linux ARM +ABIs. Coupled with many improvements to the LLVM ARM backend, Clang is now +suitable for use as a beta quality ARM compiler.</li> + </ul> </div> @@ -133,13 +168,18 @@ development. Here we include updates on these subprojects. <div class="doc_text"> -<p>Previously announced in the 2.4, 2.5, and 2.6 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 checks to find -bugs that occur on a specific path within a program.</p> - -<p>In the LLVM 2.7 time-frame, the analyzer core has ...</p> +<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a> + project is an effort to use static source code analysis techniques to + automatically find bugs in C and Objective-C programs (and hopefully <a + href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the + future</a>!). The tool is very good at finding bugs that occur on specific + paths through code, such as on error conditions.</p> + +<p>In the LLVM 2.7 time-frame, the analyzer core has made several major and + minor improvements, including better support for tracking the fields of + structures, initial support (not enabled by default yet) for doing + interprocedural (cross-function) analysis, and new checks have been added. +</p> </div> @@ -156,13 +196,23 @@ implementation of the CLI) using LLVM for static and just-in-time compilation.</p> <p> -VMKit version ?? builds with LLVM 2.7 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> +With the release of LLVM 2.7, VMKit has shifted to a great framework for writing +virtual machines. VMKit now offers precise and efficient garbage collection with +multi-threading support, thanks to the MMTk memory management toolkit, as well +as just in time and ahead of time compilation with LLVM. The major changes in +VMKit 0.27 are:</p> <ul> -<li>...</li> +<li>Garbage collection: VMKit now uses the MMTk toolkit for garbage collectors. + The first collector to be ported is the MarkSweep collector, which is precise, + and drastically improves the performance of VMKit.</li> +<li>Line number information in the JVM: by using the debug metadata of LLVM, the + JVM now supports precise line number information, useful when printing a stack + trace.</li> +<li>Interface calls in the JVM: we implemented a variant of the Interface Method + Table technique for interface calls in the JVM. +</li> </ul> </div> @@ -186,39 +236,41 @@ libgcc routines).</p> <p> All of the code in the compiler-rt project is available under the standard LLVM -License, a "BSD-style" license.</p> +License, a "BSD-style" license. New in LLVM 2.7: compiler_rt now +supports ARM targets.</p> </div> <!--=========================================================================--> <div class="doc_subsection"> -<a name="klee">KLEE: Symbolic Execution and Automatic Test Case Generator</a> +<a name="dragonegg">DragonEgg: llvm-gcc ported to gcc-4.5</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> +<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to +gcc-4.5. Unlike llvm-gcc, which makes many intrusive changes to the underlying +gcc-4.2 code, dragonegg in theory does not require any gcc-4.5 modifications +whatsoever (currently one small patch is needed). This is thanks to the new +<a href="http://gcc.gnu.org/wiki/plugins">gcc plugin architecture</a>, which +makes it possible to modify the behaviour of gcc at runtime by loading a plugin, +which is nothing more than a dynamic library which conforms to the gcc plugin +interface. DragonEgg is a gcc plugin that causes the LLVM optimizers to be run +instead of the gcc optimizers, and the LLVM code generators instead of the gcc +code generators, just like llvm-gcc. To use it, you add +"-fplugin=path/dragonegg.so" to the gcc-4.5 command line, and gcc-4.5 magically +becomes llvm-gcc-4.5! +</p> -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="dragonegg">DragonEgg: GCC-4.5 as an LLVM frontend</a> -</div> +<p> +DragonEgg is still a work in progress. Currently C works very well, while C++, +Ada and Fortran work fairly well. All other languages either don't work at all, +or only work poorly. For the moment only the x86-32 and x86-64 targets are +supported, and only on linux and darwin (darwin needs an additional gcc patch). +</p> -<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 ... +DragonEgg is a new project which is seeing its first release with llvm-2.7. </p> </div> @@ -231,9 +283,27 @@ that is loaded by gcc at runtime. It ... <div class="doc_text"> <p> -The LLVM Machine Code (MC) Toolkit project is ... +The LLVM Machine Code (aka MC) sub-project of LLVM 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. It is a sub-project of LLVM which provides it with a number of advantages +over other compilers that do not have tightly integrated assembly-level tools. +For a gentle introduction, 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> +<p>2.7 includes major parts of the work required by the new MC Project. A few + targets have been refactored to support it, and work is underway to support a + native assembler in LLVM. This work is not complete in LLVM 2.7, but it has + made substantially more progress on LLVM mainline.</p> + +<p>One minor example of what MC can do is to transcode an AT&T syntax + X86 .s file into intel syntax. You can do this with something like:</p> +<pre> + llvm-mc foo.s -output-asm-variant=1 -o foo-intel.s +</pre> + </div> @@ -250,144 +320,163 @@ The LLVM Machine Code (MC) Toolkit project is ... projects that have already been updated to work with LLVM 2.7.</p> </div> - <!--=========================================================================--> <div class="doc_subsection"> -<a name="Rubinius">Rubinius</a> +<a name="pure">Pure</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> +<a href="http://pure-lang.googlecode.com/">Pure</a> +is an algebraic/functional programming language based on term rewriting. +Programs are collections of equations which are used to evaluate expressions in +a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation, +lexical closures, a hygienic macro system (also based on term rewriting), +built-in list and matrix support (including list and matrix comprehensions) and +an easy-to-use C interface. The interpreter uses LLVM as a backend to + JIT-compile Pure programs to fast native code.</p> -<p>Since LLVM 2.5, Rubinius has made several major leaps forward, implementing -a counter based JIT, type feedback and speculative method inlining. -</p> +<p>Pure versions 0.43 and later have been tested and are known to work with +LLVM 2.7 (and continue to work with older LLVM releases >= 2.5).</p> </div> <!--=========================================================================--> <div class="doc_subsection"> -<a name="macruby">MacRuby</a> +<a name="RoadsendPHP">Roadsend PHP</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. +<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 +reimplementation of an earlier project that is now based on LLVM. </p> +</div> -<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 class="doc_subsection"> +<a name="UnladenSwallow">Unladen Swallow</a> </div> +<div class="doc_text"> +<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="pure">Pure</a> +<a name="tce">TTA-based Codesign Environment (TCE)</a> </div> <div class="doc_text"> <p> -<a href="http://pure-lang.googlecode.com/">Pure</a> -is an algebraic/functional programming language based on term rewriting. -Programs are collections of equations which are used to evaluate expressions in -a symbolic fashion. Pure offers dynamic typing, eager and lazy evaluation, -lexical closures, a hygienic macro system (also based on term rewriting), -built-in list and matrix support (including list and matrix comprehensions) and -an easy-to-use C interface. The interpreter uses LLVM as a backend to - JIT-compile Pure programs to fast native code.</p> +<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing +application-specific processors (ASP) based on the Transport triggered +architecture (TTA). The toolset provides a complete co-design flow from C/C++ +programs down to synthesizable VHDL and parallel program binaries. Processor +customization points include the register files, function units, supported +operations, and the interconnection network.</p> -<p>Pure versions ??? and later have been tested and are known to work with -LLVM 2.7 (and continue to work with older LLVM releases >= 2.3 as well). -</p> -</div> +<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target +independent optimizations and also for parts of code generation. It generates +new LLVM-based code generators "on the fly" for the designed TTA processors and +loads them in to the compiler backend as runtime libraries to avoid per-target +recompilation of larger parts of the compiler chain.</p> +</div> <!--=========================================================================--> <div class="doc_subsection"> -<a name="ldc">LLVM D Compiler</a> +<a name="safecode">SAFECode Compiler</a> </div> <div class="doc_text"> <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 2.6 release. General improvements in -this -cycle have included new inline asm constraint handling, better debug info -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. +<a href="http://safecode.cs.illinois.edu">SAFECode</a> is a memory safe C +compiler built using LLVM. It takes standard, unannotated 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. </p> </div> <!--=========================================================================--> <div class="doc_subsection"> -<a name="RoadsendPHP">Roadsend PHP</a> +<a name="icedtea">IcedTea Java Virtual Machine Implementation</a> </div> <div class="doc_text"> <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 -reimplementation of an earlier project that is now based on LLVM.</p> +<a href="http://icedtea.classpath.org/wiki/Main_Page">IcedTea</a> provides a +harness to build OpenJDK using only free software build tools and to provide +replacements for the not-yet free parts of OpenJDK. One of the extensions that +IcedTea provides is a new JIT compiler named <a +href="http://icedtea.classpath.org/wiki/ZeroSharkFaq">Shark</a> which uses LLVM +to provide native code generation without introducing processor-dependent +code. +</p> +<p>Icedtea6 1.8 and later have been tested and are known to work with +LLVM 2.7 (and continue to work with older LLVM releases >= 2.6 as well). +</p> </div> <!--=========================================================================--> <div class="doc_subsection"> -<a name="UnladenSwallow">Unladen Swallow</a> +<a name="llvm-lua">LLVM-Lua</a> </div> <div class="doc_text"> <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> +<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> +<p>LLVM-Lua 1.2.0 have been tested and is known to work with LLVM 2.7. +</p> </div> <!--=========================================================================--> <div class="doc_subsection"> -<a name="llvm-lua">llvm-lua</a> +<a name="MacRuby">MacRuby</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> +<a href="http://macruby.org">MacRuby</a> is an implementation of Ruby based on +core Mac OS technologies, sponsored by Apple Inc. It uses LLVM at runtime for +optimization passes, JIT compilation and exception handling. It also allows +static (ahead-of-time) compilation of Ruby code straight to machine code. +</p> +<p>The upcoming MacRuby 0.6 release works with LLVM 2.7. +</p> </div> <!--=========================================================================--> <div class="doc_subsection"> -<a name="icedtea">IcedTea Java Virtual Machine Implementation</a> +<a name="GHC">Glasgow Haskell Compiler (GHC)</a> </div> <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> +<a href="http://www.haskell.org/ghc/">GHC</a> is an open source, +state-of-the-art programming suite for Haskell, a standard lazy +functional programming language. It includes an optimizing static +compiler generating good code for a variety of platforms, together +with an interactive system for convenient, quick development.</p> + +<p>In addition to the existing C and native code generators, GHC now +supports an <a +href="http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/Backends/LLVM">LLVM +code generator</a>. GHC supports LLVM 2.7.</p> +</div> <!-- *********************************************************************** --> @@ -407,6 +496,39 @@ in this section. <!--=========================================================================--> <div class="doc_subsection"> +<a name="orgchanges">LLVM Community Changes</a> +</div> + +<div class="doc_text"> + +<p>In addition to changes to the code, between LLVM 2.6 and 2.7, a number of +organization changes have happened: +</p> + +<ul> +<li>LLVM has a new <a href="http://llvm.org/Logo.html">official logo</a>!</li> + +<li>Ted Kremenek and Doug Gregor have stepped forward as <a + href="http://llvm.org/docs/DeveloperPolicy.html#owners">Code Owners</a> of the + Clang static analyzer and the Clang frontend, respectively.</li> + +<li>LLVM now has an <a href="http://blog.llvm.org">official Blog</a> at + <a href="http://blog.llvm.org">http://blog.llvm.org</a>. This is a great way + to learn about new LLVM-related features as they are implemented. Several + features in this release are already explained on the blog.</li> + +<li>The LLVM web pages are now checked into the SVN server, in the "www", + "www-pubs" and "www-releases" SVN modules. Previously they were hidden in a + largely inaccessible old CVS server.</li> + +<li><a href="http://llvm.org">llvm.org</a> is now hosted on a new (and much + faster) server. It is still graciously hosted at the University of Illinois + of Urbana Champaign.</li> +</ul> +</div> + +<!--=========================================================================--> +<div class="doc_subsection"> <a name="majorfeatures">Major New Features</a> </div> @@ -415,7 +537,40 @@ in this section. <p>LLVM 2.7 includes several major new capabilities:</p> <ul> -<li>...</li> +<li>2.7 includes initial support for the <a + href="http://en.wikipedia.org/wiki/MicroBlaze">MicroBlaze</a> target. + MicroBlaze is a soft processor core designed for Xilinx FPGAs.</li> + +<li>2.7 includes a new LLVM IR "extensible metadata" feature. This feature + supports many different use cases, including allowing front-end authors to + encode source level information into LLVM IR, which is consumed by later + language-specific passes. This is a great way to do high-level optimizations + like devirtualization, type-based alias analysis, etc. See the <a + href="http://blog.llvm.org/2010/04/extensible-metadata-in-llvm-ir.html"> + Extensible Metadata Blog Post</a> for more information.</li> + +<li>2.7 encodes <a href="SourceLevelDebugging.html">debug information</a> +in a completely new way, built on extensible metadata. The new implementation +is much more memory efficient and paves the way for improvements to optimized +code debugging experience.</li> + +<li>2.7 now directly supports taking the address of a label and doing an + indirect branch through a pointer. This is particularly useful for + interpreter loops, and is used to implement the GCC "address of label" + extension. For more information, see the <a +href="http://blog.llvm.org/2010/01/address-of-label-and-indirect-branches.html"> +Address of Label and Indirect Branches in LLVM IR Blog Post</a>. + +<li>2.7 is the first release to start supporting APIs for assembling and + disassembling target machine code. These APIs are useful for a variety of + low level clients, and are surfaced in the new "enhanced disassembly" API. + For more information see the <a + href="http://blog.llvm.org/2010/01/x86-disassembler.html">The X86 + Disassembler Blog Post</a> for more information.</li> + +<li>2.7 includes major parts of the work required by the new MC Project, + see the <a href="#mc">MC update above</a> for more information.</li> + </ul> </div> @@ -430,7 +585,30 @@ in this section. expose new optimization opportunities:</p> <ul> -<li>...</li> +<li>LLVM IR now supports a 16-bit "half float" data type through <a + href="LangRef.html#int_fp16">two new intrinsics</a> and APFloat support.</li> +<li>LLVM IR supports two new <a href="LangRef.html#fnattrs">function + attributes</a>: inlinehint and alignstack(n). The former is a hint to the + optimizer that a function was declared 'inline' and thus the inliner should + weight it higher when considering inlining it. The later + indicates to the code generator that the function diverges from the platform + ABI on stack alignment.</li> +<li>The new <a href="LangRef.html#int_objectsize">llvm.objectsize</a> intrinsic + allows the optimizer to infer the sizes of memory objects in some cases. + This intrinsic is used to implement the GCC <tt>__builtin_object_size</tt> + extension.</li> +<li>LLVM IR now supports marking load and store instructions with <a + href="LangRef.html#i_load">"non-temporal" hints</a> (building on the new + metadata feature). This hint encourages the code + generator to generate non-temporal accesses when possible, which are useful + for code that is carefully managing cache behavior. Currently, only the + X86 backend provides target support for this feature.</li> + +<li>LLVM 2.7 has pre-alpha support for <a + href="LangRef.html#t_union">unions in LLVM IR</a>. + Unfortunately, this support is not really usable in 2.7, so if you're + interested in pushing it forward, please help contribute to LLVM mainline.</li> + </ul> </div> @@ -447,12 +625,51 @@ release includes a few major enhancements and additions to the optimizers:</p> <ul> -<li>...</li> +<li>The inliner reuses now merges arrays stack objects in different callees when + inlining multiple call sites into one function. This reduces the stack size + of the resultant function.</li> +<li>The -basicaa alias analysis pass (which is the default) has been improved to + be less dependent on "type safe" pointers. It can now look through bitcasts + and other constructs more aggressively, allowing better load/store + optimization.</li> +<li>The load elimination optimization in the GVN Pass [<a +href="http://blog.llvm.org/2009/12/introduction-to-load-elimination-in-gvn.html">intro + blog post</a>] has been substantially improved to be more aggressive about + partial redundancy elimination and do more aggressive phi translation. Please + see the <a + href="http://blog.llvm.org/2009/12/advanced-topics-in-redundant-load.html"> + Advanced Topics in Redundant Load Elimination with a Focus on PHI Translation + Blog Post</a> for more details.</li> +<li>The module <a href="LangRef.html#datalayout">target data string</a> now + includes a notion of 'native' integer data types for the target. This + helps mid-level optimizations avoid promoting complex sequences of + operations to data types that are not natively supported (e.g. converting + i32 operations to i64 on 32-bit chips).</li> +<li>The mid-level optimizer is now conservative when operating on a module with + no target data. Previously, it would default to SparcV9 settings, which is + not what most people expected.</li> +<li>Jump threading is now much more aggressive at simplifying correlated + conditionals and threading blocks with otherwise complex logic. It has + subsumed the old "Conditional Propagation" pass, and -condprop has been + removed from LLVM 2.7.</li> +<li>The -instcombine pass has been refactored from being one huge file to being + a library of its own. Internally, it uses a customized IRBuilder to clean + it up and simplify it.</li> + +<li>The optimal edge profiling pass is reliable and much more complete than in + 2.6. It can be used with the llvm-prof tool but isn't wired up to the + llvm-gcc and clang command line options yet.</li> + +<li>A new experimental alias analysis implementation, -scev-aa, has been added. + It uses LLVM's Scalar Evolution implementation to do symbolic analysis of + pointer offset expressions to disambiguate pointers. It can catch a few + cases that basicaa cannot, particularly in complex loop nests.</li> + +<li>The default pass ordering has been tweaked for improved optimization + effectiveness.</li> </ul> -<p>Also, -anders-aa was removed</p> - </div> @@ -464,15 +681,20 @@ release includes a few major enhancements and additions to the optimizers:</p> <div class="doc_text"> <ul> -<li>The JIT now <a -href="http://llvm.org/viewvc/llvm-project?view=rev&revision=85295">defaults +<li>The JIT now supports generating debug information and is compatible with +the new GDB 7.0 (and later) interfaces for registering dynamically generated +debug info.</li> + +<li>The JIT now <a href="http://llvm.org/PR5184">defaults to compiling eagerly</a> to avoid a race condition in the lazy JIT. Clients that still want the lazy JIT can switch it on by calling <tt>ExecutionEngine::DisableLazyCompilation(false)</tt>.</li> + <li>It is now possible to create more than one JIT instance in the same process. These JITs can generate machine code in parallel, although <a href="http://llvm.org/docs/ProgrammersManual.html#jitthreading">you still have to obey the other threading restrictions</a>.</li> + </ul> </div> @@ -489,8 +711,49 @@ infrastructure, which allows us to implement more aggressive algorithms and make it run faster:</p> <ul> - -<li>...</li> +<li>The 'llc -asm-verbose' option (which is now the default) has been enhanced + to emit many useful comments to .s files indicating information about spill + slots and loop nest structure. This should make it much easier to read and + understand assembly files. This is wired up in llvm-gcc and clang to + the <tt>-fverbose-asm</tt> option.</li> + +<li>New LSR with "full strength reduction" mode, which can reduce address + register pressure in loops where address generation is important.</li> + +<li>A new codegen level Common Subexpression Elimination pass (MachineCSE) + is available and enabled by default. It catches redundancies exposed by + lowering.</li> +<li>A new pre-register-allocation tail duplication pass is available and enabled + by default, it can substantially improve branch prediction quality in some + cases.</li> +<li>A new sign and zero extension optimization pass (OptimizeExtsPass) + is available and enabled by default. This pass can takes advantage + architecture features like x86-64 implicit zero extension behavior and + sub-registers.</li> +<li>The code generator now supports a mode where it attempts to preserve the + order of instructions in the input code. This is important for source that + is hand scheduled and extremely sensitive to scheduling. It is compatible + with the GCC <tt>-fno-schedule-insns</tt> option.</li> +<li>The target-independent code generator now supports generating code with + arbitrary numbers of result values. Returning more values than was + previously supported is handled by returning through a hidden pointer. In + 2.7, only the X86 and XCore targets have adopted support for this + though.</li> +<li>The code generator now supports generating code that follows the + <a href="LangRef.html#callingconv">Glasgow Haskell Compiler Calling + Convention</a> and ABI.</li> +<li>The "<a href="CodeGenerator.html#selectiondag_select">DAG instruction + selection</a>" phase of the code generator has been largely rewritten for + 2.7. Previously, tblgen spit out tons of C++ code which was compiled and + linked into the target to do the pattern matching, now it emits a much + smaller table which is read by the target-independent code. The primary + advantages of this approach is that the size and compile time of various + targets is much improved. The X86 code generator shrunk by 1.5MB of code, + for example.</li> +<li>Almost the entire code generator has switched to emitting code through the + MC interfaces instead of printing textually to the .s file. This led to a + number of cleanups and speedups. In 2.7, debug an exception handling + information does not go through MC yet.</li> </ul> </div> @@ -504,8 +767,11 @@ it run faster:</p> </p> <ul> - -<li>...</li> +<li>The X86 backend now optimizes tails calls much more aggressively for + functions that use the standard C calling convention.</li> +<li>The X86 backend now models scalar SSE registers as subregs of the SSE vector + registers, making the code generator more aggressive in cases where scalars + and vector types are mixed.</li> </ul> @@ -513,28 +779,6 @@ it run faster:</p> <!--=========================================================================--> <div class="doc_subsection"> -<a name="pic16">PIC16 Target Improvements</a> -</div> - -<div class="doc_text"> -<p>New features of the PIC16 target include: -</p> - -<ul> -<li>...</li> -</ul> - -<p>Things not yet supported:</p> - -<ul> -<li>Variable arguments.</li> -<li>Interrupts/programs.</li> -</ul> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> <a name="ARM">ARM Target Improvements</a> </div> @@ -544,25 +788,31 @@ it run faster:</p> <ul> -<li>...</li> -</ul> +<li>The ARM backend now generates instructions in unified assembly syntax.</li> +<li>llvm-gcc now has complete support for the ARM v7 NEON instruction set. This + support differs slightly from the GCC implementation. Please see the + <a +href="http://blog.llvm.org/2010/04/arm-advanced-simd-neon-intrinsics-and.html"> + ARM Advanced SIMD (NEON) Intrinsics and Types in LLVM Blog Post</a> for + helpful information if migrating code from GCC to LLVM-GCC.</li> + +<li>The ARM and Thumb code generators now use register scavenging for stack + object address materialization. This allows the use of R3 as a general + purpose register in Thumb1 code, as it was previous reserved for use in + stack address materialization. Secondly, sequential uses of the same + value will now re-use the materialized constant.</li> -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="OtherTarget">Other Target Specific Improvements</a> -</div> +<li>The ARM backend now has good support for ARMv4 targets and has been tested + on StrongARM hardware. Previously, LLVM only supported ARMv4T and + newer chips.</li> -<div class="doc_text"> -<p>New features of other targets include: -</p> +<li>Atomic builtins are now supported for ARMv6 and ARMv7 (__sync_synchronize, + __sync_fetch_and_add, etc.).</li> -<ul> -<li>...</li> </ul> + </div> <!--=========================================================================--> @@ -577,7 +827,34 @@ it run faster:</p> </p> <ul> -<li>...</li> +<li>The optimizer uses the new CodeMetrics class to measure the size of code. + Various passes (like the inliner, loop unswitcher, etc) all use this to make + more accurate estimates of the code size impact of various + optimizations.</li> +<li>A new <a href="http://llvm.org/doxygen/InstructionSimplify_8h-source.html"> + llvm/Analysis/InstructionSimplify.h</a> interface is available for doing + symbolic simplification of instructions (e.g. <tt>a+0</tt> -> <tt>a</tt>) + without requiring the instruction to exist. This centralizes a lot of + ad-hoc symbolic manipulation code scattered in various passes.</li> +<li>The optimizer now uses a new <a + href="http://llvm.org/doxygen/SSAUpdater_8h-source.html">SSAUpdater</a> + class which efficiently supports + doing unstructured SSA update operations. This centralized a bunch of code + scattered throughout various passes (e.g. jump threading, lcssa, + loop rotate, etc) for doing this sort of thing. The code generator has a + similar <a href="http://llvm.org/doxygen/MachineSSAUpdater_8h-source.html"> + MachineSSAUpdater</a> class.</li> +<li>The <a href="http://llvm.org/doxygen/Regex_8h-source.html"> + llvm/Support/Regex.h</a> header exposes a platform independent regular + expression API. Building on this, the <a + href="TestingGuide.html#FileCheck">FileCheck</a> utility now supports + regular exressions.</li> +<li>raw_ostream now supports a circular "debug stream" accessed with "dbgs()". + By default, this stream works the same way as "errs()", but if you pass + <tt>-debug-buffer-size=1000</tt> to opt, the debug stream is capped to a + fixed sized circular buffer and the output is printed at the end of the + program's execution. This is helpful if you have a long lived compiler + process and you're interested in seeing snapshots in time.</li> </ul> @@ -592,7 +869,16 @@ it run faster:</p> <p>Other miscellaneous features include:</p> <ul> -<li>...</li> +<li>You can now build LLVM as a big dynamic library (e.g. "libllvm2.7.so"). To + get this, configure LLVM with the --enable-shared option.</li> + +<li>LLVM command line tools now overwrite their output by default. Previously, + they would only do this with -f. This makes them more convenient to use, and + behave more like standard unix tools.</li> + +<li>The opt and llc tools now autodetect whether their input is a .ll or .bc + file, and automatically do the right thing. This means you don't need to + explicitly use the llvm-as tool for most things.</li> </ul> </div> @@ -610,20 +896,48 @@ on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading from the previous release.</p> <ul> + +<li> +The Andersen's alias analysis ("anders-aa") pass, the Predicate Simplifier +("predsimplify") pass, the LoopVR pass, the GVNPRE pass, and the random sampling +profiling ("rsprofiling") passes have all been removed. They were not being +actively maintained and had substantial problems. If you are interested in +these components, you are welcome to ressurect them from SVN, fix the +correctness problems, and resubmit them to mainline.</li> + +<li>LLVM now defaults to building most libraries with RTTI turned off, providing +a code size reduction. Packagers who are interested in building LLVM to support +plugins that require RTTI information should build with "make REQUIRE_RTTI=1" +and should read the new <a href="Packaging.html">Advice on Packaging LLVM</a> +document.</li> + <li>The LLVM interpreter now defaults to <em>not</em> using <tt>libffi</tt> even if you have it installed. This makes it more likely that an LLVM built on one system will work when copied to a similar system. To use <tt>libffi</tt>, -configure with <tt>--enable-libffi</tt>. -</li> -</ul> +configure with <tt>--enable-libffi</tt>.</li> + +<li>Debug information uses a completely different representation, an LLVM 2.6 +.bc file should work with LLVM 2.7, but debug info won't come forward.</li> +<li>The LLVM 2.6 (and earlier) "malloc" and "free" instructions got removed, + along with LowerAllocations pass. Now you should just use a call to the + malloc and free functions in libc. These calls are optimized as well as + the old instructions were.</li> +</ul> <p>In addition, many APIs have changed in this release. Some of the major LLVM API changes are:</p> <ul> +<li>Just about everything has been converted to use <tt>raw_ostream</tt> instead of + <tt>std::ostream</tt>.</li> +<li><tt>llvm/ADT/iterator.h</tt> has been removed, just use <tt><iterator></tt> + instead.</li> +<li>The <tt>Streams.h</tt> file and <tt>DOUT</tt> got removed, use <tt>DEBUG(errs() << ...);</tt> + instead.</li> +<li>The <tt>TargetAsmInfo</tt> interface was renamed to <tt>MCAsmInfo</tt>.</li> <li><tt>ModuleProvider</tt> has been <a -href="http://llvm.org/viewvc/llvm-project?view=rev&revision=94686">removed</a> +href="http://llvm.org/viewvc/llvm-project?view=rev&revision=94686">removed</a> and its methods moved to <tt>Module</tt> and <tt>GlobalValue</tt>. Most clients can remove uses of <tt>ExistingModuleProvider</tt>, replace <tt>getBitcodeModuleProvider</tt> with @@ -641,15 +955,24 @@ Clients must replace calls to <tt>GlobalValue::hasNotBeenReadFromBitcode</tt> with <tt>GlobalValue::isMaterializable</tt>.</li> -<li>FIXME: Debug info has been totally redone. Add pointers to new APIs. Substantial caveats about compatibility of .ll and .bc files.</li> - -<li>The <tt>llvm/Support/DataTypes.h</tt> header has moved -to <tt>llvm/System/DataTypes.h</tt>.</li> - <li>The <tt>isInteger</tt>, <tt>isIntOrIntVector</tt>, <tt>isFloatingPoint</tt>, <tt>isFPOrFPVector</tt> and <tt>isFPOrFPVector</tt> methods have been renamed <tt>isIntegerTy</tt>, <tt>isIntOrIntVectorTy</tt>, <tt>isFloatingPointTy</tt>, <tt>isFPOrFPVectorTy</tt> and <tt>isFPOrFPVectorTy</tt> respectively.</li> + +<li><tt>llvm::Instruction::clone()</tt> no longer takes argument.</li> +<li><tt>raw_fd_ostream</tt>'s constructor now takes a flag argument, not individual + booleans (see <tt>include/llvm/Support/raw_ostream.h</tt> for details).</li> +<li>Some header files have been renamed: +<ul> + <li><tt>llvm/Support/AIXDataTypesFix.h</tt> to + <tt>llvm/System/AIXDataTypesFix.h</tt></li> + <li><tt>llvm/Support/DataTypes.h</tt> to <tt>llvm/System/DataTypes.h</tt></li> + <li><tt>llvm/Transforms/Utils/InlineCost.h</tt> to + <tt>llvm/Analysis/InlineCost.h</tt></li> + <li><tt>llvm/Support/Mangler.h</tt> to <tt>llvm/Target/Mangler.h</tt></li> + <li><tt>llvm/Analysis/Passes.h</tt> to <tt>llvm/CodeGen/Passes.h</tt></li> +</ul></li> </ul> </div> @@ -670,7 +993,7 @@ to <tt>llvm/System/DataTypes.h</tt>.</li> <li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat 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 +<li>PowerPC and X86-based Mac OS X systems, running 10.4 and above in 32-bit 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 @@ -699,13 +1022,7 @@ 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 is to upgrade to binutils 2.17 or - later.</li> - +<ul> <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="GettingStarted.html#brokengcc">Broken versions of GCC and other tools</a>. @@ -731,10 +1048,11 @@ components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p> <ul> -<li>The MSIL, 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. The ELF writer is experimental.</li> +<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze + backends are experimental.</li> +<li><tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only + supported value for this option. The MachO writer is experimental, and + works much better in mainline SVN.</li> </ul> </div> @@ -755,13 +1073,10 @@ href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p> to generate code for systems that don't have SSE2.</li> <li>Win64 code generation wasn't widely tested. Everything should work, but we expect small issues to happen. Also, llvm-gcc cannot build the mingw64 - runtime currently due - to <a href="http://llvm.org/PR2255">several</a> - <a href="http://llvm.org/PR2257">bugs</a> and due to lack of support for - the - 'u' inline assembly constraint and for X87 floating point inline assembly.</li> + runtime currently due to lack of support for the 'u' inline assembly + constraint and for X87 floating point inline assembly.</li> <li>The X86-64 backend does not yet support the LLVM IR instruction - <tt>va_arg</tt>. Currently, the llvm-gcc and front-ends support variadic + <tt>va_arg</tt>. Currently, front-ends support variadic argument constructs on X86-64 by lowering them manually.</li> </ul> @@ -789,9 +1104,6 @@ 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> @@ -865,7 +1177,7 @@ appropriate nops inserted to ensure restartability.</li> <!-- ======================================================================= --> <div class="doc_subsection"> - <a name="c-fe">Known problems with the llvm-gcc C front-end</a> + <a name="c-fe">Known problems with the llvm-gcc C and C++ front-end</a> </div> <div class="doc_text"> @@ -876,27 +1188,6 @@ appropriate nops inserted to ensure restartability.</li> supported on some targets (these are used when you take the address of a nested function).</p> -<p>If you run into GCC extensions which are not supported, please let us know. -</p> - -</div> - -<!-- ======================================================================= --> -<div class="doc_subsection"> - <a name="c++-fe">Known problems with the llvm-gcc C++ front-end</a> -</div> - -<div class="doc_text"> - -<p>The C++ front-end is considered to be fully -tested and works for a number of non-trivial programs, including LLVM -itself, Qt, Mozilla, etc.</p> - -<ul> -<li>Exception handling works well on the X86 and PowerPC targets. Currently - only Linux and Darwin targets are supported (both 32 and 64 bit).</li> -</ul> - </div> <!-- ======================================================================= --> @@ -951,20 +1242,6 @@ 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> |