diff options
| author | Chris Lattner <sabre@nondot.org> | 2011-03-10 07:43:44 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2011-03-10 07:43:44 +0000 |
| commit | be2e1b50c427278e45736388a3e7fea0dd825513 (patch) | |
| tree | e088ea73fa1bf339f3c2277b2857cea62718ef6f /docs | |
| parent | 6a951ac63fd6a9aa769c6d98b544b886e5b5d307 (diff) | |
| download | external_llvm-be2e1b50c427278e45736388a3e7fea0dd825513.zip external_llvm-be2e1b50c427278e45736388a3e7fea0dd825513.tar.gz external_llvm-be2e1b50c427278e45736388a3e7fea0dd825513.tar.bz2 | |
rip out llvm 2.8 release notes to make room for llvm 2.9 notes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127399 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/ReleaseNotes.html | 716 |
1 files changed, 50 insertions, 666 deletions
diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html index 2f83b94..efda3a4 100644 --- a/docs/ReleaseNotes.html +++ b/docs/ReleaseNotes.html @@ -5,11 +5,11 @@ <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <meta encoding="utf8"> <link rel="stylesheet" href="llvm.css" type="text/css"> - <title>LLVM 2.8 Release Notes</title> + <title>LLVM 2.9 Release Notes</title> </head> <body> -<div class="doc_title">LLVM 2.8 Release Notes</div> +<div class="doc_title">LLVM 2.9 Release Notes</div> <img align=right src="http://llvm.org/img/DragonSmall.png" width="136" height="136" alt="LLVM Dragon Logo"> @@ -17,8 +17,8 @@ <ol> <li><a href="#intro">Introduction</a></li> <li><a href="#subproj">Sub-project Status Update</a></li> - <li><a href="#externalproj">External Projects Using LLVM 2.8</a></li> - <li><a href="#whatsnew">What's New in LLVM 2.8?</a></li> + <li><a href="#externalproj">External Projects Using LLVM 2.9</a></li> + <li><a href="#whatsnew">What's New in LLVM 2.9?</a></li> <li><a href="GettingStarted.html">Installation Instructions</a></li> <li><a href="#knownproblems">Known Problems</a></li> <li><a href="#additionalinfo">Additional Information</a></li> @@ -28,13 +28,11 @@ <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 2.8 +<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.9 release.<br> You may prefer the -<a href="http://llvm.org/releases/2.7/docs/ReleaseNotes.html">LLVM 2.7 +<a href="http://llvm.org/releases/2.8/docs/ReleaseNotes.html">LLVM 2.8 Release Notes</a>.</h1> ---> <!-- *********************************************************************** --> <div class="doc_section"> @@ -45,7 +43,7 @@ Release Notes</a>.</h1> <div class="doc_text"> <p>This document contains the release notes for the LLVM Compiler -Infrastructure, release 2.8. Here we describe the status of LLVM, including +Infrastructure, release 2.9. Here we describe the status of LLVM, including major improvements from the previous release and significant known problems. All LLVM releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM releases web site</a>.</p> @@ -62,17 +60,16 @@ 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> - + +<!-- NOTE: last release for llvm-gcc --> <!-- Almost dead code. - include/llvm/Analysis/LiveValues.h => Dan - lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8. - GEPSplitterPass + lib/Transforms/IPO/MergeFunctions.cpp => consider for 3.0. --> -<!-- Features that need text if they're finished for 2.9: +<!-- Features that need text if they're finished for 3.0: combiner-aa? strong phi elim loop dependence analysis @@ -80,9 +77,6 @@ Almost dead code. CorrelatedValuePropagation --> - <!-- Announcement, lldb, libc++ --> - - <!-- *********************************************************************** --> <div class="doc_section"> <a name="subproj">Sub-project Status Update</a> @@ -91,7 +85,7 @@ Almost dead code. <div class="doc_text"> <p> -The LLVM 2.8 distribution currently consists of code from the core LLVM +The LLVM 2.9 distribution currently consists of code from the core LLVM repository (which roughly includes the LLVM optimizers, code generators and supporting tools), the Clang repository and the llvm-gcc repository. In addition to this code, the LLVM Project includes other sub-projects that are in @@ -117,29 +111,10 @@ integrating with other development tools. Clang is considered a production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86 (32- and 64-bit), and for darwin-arm targets.</p> -<p>In the LLVM 2.8 time-frame, the Clang team has made many improvements:</p> - - <ul> - <li>Clang C++ is now feature-complete with respect to the ISO C++ 1998 and 2003 standards.</li> - <li>Added support for Objective-C++.</li> - <li>Clang now uses LLVM-MC to directly generate object code and to parse inline assembly (on Darwin).</li> - <li>Introduced many new warnings, including <code>-Wmissing-field-initializers</code>, <code>-Wshadow</code>, <code>-Wno-protocol</code>, <code>-Wtautological-compare</code>, <code>-Wstrict-selector-match</code>, <code>-Wcast-align</code>, <code>-Wunused</code> improvements, and greatly improved format-string checking.</li> - <li>Introduced the "libclang" library, a C interface to Clang intended to support IDE clients.</li> - <li>Added support for <code>#pragma GCC visibility</code>, <code>#pragma align</code>, and others.</li> - <li>Added support for SSE, AVX, ARM NEON, and AltiVec.</li> - <li>Improved support for many Microsoft extensions.</li> - <li>Implemented support for blocks in C++.</li> - <li>Implemented precompiled headers for C++.</li> - <li>Improved abstract syntax trees to retain more accurate source information.</li> - <li>Added driver support for handling LLVM IR and bitcode files directly.</li> - <li>Major improvements to compiler correctness for exception handling.</li> - <li>Improved generated code quality in some areas: - <ul> - <li>Good code generation for X86-32 and X86-64 ABI handling.</li> - <li>Improved code generation for bit-fields, although important work remains.</li> - </ul> - </li> - </ul> +<p>In the LLVM 2.9 time-frame, the Clang team has made many improvements:</p> + +<ul> +</ul> </div> <!--=========================================================================--> @@ -156,8 +131,7 @@ production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86 future</a>!). The tool is very good at finding bugs that occur on specific paths through code, such as on error conditions.</p> -<p>The LLVM 2.8 release fixes a number of bugs and slightly improves precision - over 2.7, but there are no major new features in the release. +<p>The LLVM 2.9 release... </p> </div> @@ -168,6 +142,8 @@ production-quality compiler for C, Objective-C, C++ and Objective-C++ on x86 </div> <div class="doc_text"> +NOTE: This should be written to be self-contained without referencing llvm-gcc. + <p> <a href="http://dragonegg.llvm.org/">DragonEgg</a> is a port of llvm-gcc to gcc-4.5. Unlike llvm-gcc, dragonegg in theory does not require any gcc-4.5 @@ -186,32 +162,24 @@ linux and darwin (darwin may need additional gcc patches). </p> <p> -The 2.8 release has the following notable changes: +The 2.9 release has the following notable changes: <ul> -<li>The plugin loads faster due to exporting fewer symbols.</li> -<li>Additional vector operations such as addps256 are now supported.</li> -<li>Ada global variables with no initial value are no longer zero initialized, -resulting in better optimization.</li> -<li>The '-fplugin-arg-dragonegg-enable-gcc-optzns' flag now runs all gcc -optimizers, rather than just a handful.</li> -<li>Fortran programs using common variables now link correctly.</li> -<li>GNU OMP constructs no longer crash the compiler.</li> </ul> </div> <!--=========================================================================--> <div class="doc_subsection"> -<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a> +<a name="vmkit">VMKit: JVM Virtual Machine Implementation</a> </div> <div class="doc_text"> <p> The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of a Java Virtual Machine (Java VM or JVM) that uses LLVM for static and -just-in-time compilation. As of LLVM 2.8, VMKit now supports copying garbage -collectors, and can be configured to use MMTk's copy mark-sweep garbage -collector. In LLVM 2.8, the VMKit .NET VM is no longer being maintained. +just-in-time compilation. + +UPDATE. </p> </div> @@ -233,10 +201,11 @@ libgcc routines).</p> <p> All of the code in the compiler-rt project is available under the standard LLVM -License, a "BSD-style" license. New in LLVM 2.8, compiler_rt now supports -soft floating point (for targets that don't have a real floating point unit), -and includes an extensive testsuite for the "blocks" language feature and the -blocks runtime included in compiler_rt.</p> +License, a "BSD-style" license. + +NEW: MIT License as well. + +New in LLVM 2.9, UPDATE</p> </div> @@ -254,10 +223,13 @@ libraries in the larger LLVM Project, such as the Clang expression parser, the LLVM disassembler and the LLVM JIT.</p> <p> -LLDB is in early development and not included as part of the LLVM 2.8 release, +LLDB is in early development and not included as part of the LLVM 2.9 release, +UPDATE! + +<!-- but is mature enough to support basic debugging scenarios on Mac OS X in C, Objective-C and C++. We'd really like help extending and expanding LLDB to -support new platforms, new languages, new architectures, and new features. +support new platforms, new languages, new architectures, and new features.--> </p> </div> @@ -275,9 +247,11 @@ ground up to specifically target the forthcoming C++'0X standard and focus on delivering great performance.</p> <p> -As of the LLVM 2.8 release, libc++ is virtually feature complete, but would +As of the LLVM 2.9 release, UPDATE! + +<!--libc++ is virtually feature complete, but would benefit from more testing and better integration with Clang++. It is also -looking forward to the C++ committee finalizing the C++'0x standard. +looking forward to the C++ committee finalizing the C++'0x standard.--> </p> </div> @@ -298,31 +272,14 @@ states. This allows it to construct testcases that lead to faults and can even be used to verify some algorithms. </p> -<p>Although KLEE does not have any major new features as of 2.8, we have made -various minor improvements, particular to ease development:</p> -<ul> - <li>Added support for LLVM 2.8. KLEE currently maintains compatibility with - LLVM 2.6, 2.7, and 2.8.</li> - <li>Added a buildbot for 2.6, 2.7, and trunk. A 2.8 buildbot will be coming - soon following release.</li> - <li>Fixed many C++ code issues to allow building with Clang++. Mostly - complete, except for the version of MiniSAT which is inside the KLEE STP - version.</li> - <li>Improved support for building with separate source and build - directories.</li> - <li>Added support for "long double" on x86.</li> - <li>Initial work on KLEE support for using 'lit' test runner instead of - DejaGNU.</li> - <li>Added <tt>configure</tt> support for using an external version of - STP.</li> -</ul> +<p>UPDATE!</p> </div> <!-- *********************************************************************** --> <div class="doc_section"> - <a name="externalproj">External Open Source Projects Using LLVM 2.8</a> + <a name="externalproj">External Open Source Projects Using LLVM 2.9</a> </div> <!-- *********************************************************************** --> @@ -330,264 +287,15 @@ various minor improvements, particular to ease development:</p> <p>An exciting aspect of LLVM is that it is used as an enabling technology for a lot of other language and tools projects. This section lists some of the - projects that have already been updated to work with LLVM 2.8.</p> -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="tce">TTA-based Codesign Environment (TCE)</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://tce.cs.tut.fi/">TCE</a> is a toolset for designing -application-specific processors (ASP) based on the Transport triggered -architecture (TTA). The toolset provides a complete co-design flow from C/C++ -programs down to synthesizable VHDL and parallel program binaries. Processor -customization points include the register files, function units, supported -operations, and the interconnection network.</p> - -<p>TCE uses llvm-gcc/Clang and LLVM for C/C++ language support, target -independent optimizations and also for parts of code generation. It generates -new LLVM-based code generators "on the fly" for the designed TTA processors and -loads them in to the compiler backend as runtime libraries to avoid per-target -recompilation of larger parts of the compiler chain.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="Horizon">Horizon Bytecode Compiler</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://www.quokforge.org/projects/horizon">Horizon</a> is a bytecode -language and compiler written on top of LLVM, intended for producing -single-address-space managed code operating systems that -run faster than the equivalent multiple-address-space C systems. -More in-depth blurb is available on the <a -href="http://www.quokforge.org/projects/horizon/wiki/Wiki">wiki</a>.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="clamav">Clam AntiVirus</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://www.clamav.net">Clam AntiVirus</a> is an open source (GPL) -anti-virus toolkit for UNIX, designed especially for e-mail scanning on mail -gateways. Since version 0.96 it has <a -href="http://vrt-sourcefire.blogspot.com/2010/09/introduction-to-clamavs-low-level.html">bytecode -signatures</a> that allow writing detections for complex malware. It -uses LLVM's JIT to speed up the execution of bytecode on -X86, X86-64, PPC32/64, falling back to its own interpreter otherwise. -The git version was updated to work with LLVM 2.8. -</p> - -<p>The <a -href="http://git.clamav.net/gitweb?p=clamav-bytecode-compiler.git;a=blob_plain;f=docs/user/clambc-user.pdf"> -ClamAV bytecode compiler</a> uses Clang and LLVM to compile a C-like -language, insert runtime checks, and generate ClamAV bytecode.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="pure">Pure</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> - -<p>Pure versions 0.44 and later have been tested and are known to work with -LLVM 2.8 (and continue to work with older LLVM releases >= 2.5).</p> - + projects that have already been updated to work with LLVM 2.9.</p> </div> -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="GHC">Glasgow Haskell Compiler (GHC)</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://www.haskell.org/ghc/">GHC</a> is an open source, -state-of-the-art programming suite for -Haskell, a standard lazy functional programming language. It includes -an optimizing static compiler generating good code for a variety of -platforms, together with an interactive system for convenient, quick -development.</p> - -<p>In addition to the existing C and native code generators, GHC 7.0 now -supports an <a -href="http://hackage.haskell.org/trac/ghc/wiki/Commentary/Compiler/Backends/LLVM">LLVM -code generator</a>. GHC supports LLVM 2.7 and later.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="Clay">Clay Programming Language</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://tachyon.in/clay/">Clay</a> is a new systems programming -language that is specifically designed for generic programming. It makes -generic programming very concise thanks to whole program type propagation. It -uses LLVM as its backend.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="llvm-py">llvm-py Python Bindings for LLVM</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://www.mdevan.org/llvm-py/">llvm-py</a> has been updated to work -with LLVM 2.8. llvm-py provides Python bindings for LLVM, allowing you to write a -compiler backend or a VM in Python.</p> - -</div> - - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="FAUST">FAUST Real-Time Audio Signal Processing Language</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://faust.grame.fr">FAUST</a> is a compiled language for real-time -audio signal processing. The name FAUST stands for Functional AUdio STream. Its -programming model combines two approaches: functional programming and block -diagram composition. In addition with the C, C++, JAVA output formats, the -Faust compiler can now generate LLVM bitcode, and works with LLVM 2.7 and -2.8.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="jade">Jade Just-in-time Adaptive Decoder Engine</a> -</div> - -<div class="doc_text"> -<p><a -href="http://sourceforge.net/apps/trac/orcc/wiki/JadeDocumentation">Jade</a> -(Just-in-time Adaptive Decoder Engine) is a generic video decoder engine using -LLVM for just-in-time compilation of video decoder configurations. Those -configurations are designed by MPEG Reconfigurable Video Coding (RVC) committee. -MPEG RVC standard is built on a stream-based dataflow representation of -decoders. It is composed of a standard library of coding tools written in -RVC-CAL language and a dataflow configuration — block diagram — -of a decoder.</p> - -<p>Jade project is hosted as part of the <a href="http://orcc.sf.net">Open -RVC-CAL Compiler</a> and requires it to translate the RVC-CAL standard library -of video coding tools into an LLVM assembly code.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="neko_llvm_jit">LLVM JIT for Neko VM</a> -</div> - -<div class="doc_text"> -<p><a href="http://github.com/vava/neko_llvm_jit">Neko LLVM JIT</a> -replaces the standard Neko JIT with an LLVM-based implementation. While not -fully complete, it is already providing a 1.5x speedup on 64-bit systems. -Neko LLVM JIT requires LLVM 2.8 or later.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="crack">Crack Scripting Language</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://code.google.com/p/crack-language/">Crack</a> aims to provide -the ease of development of a scripting language with the performance of a -compiled language. The language derives concepts from C++, Java and Python, -incorporating object-oriented programming, operator overloading and strong -typing. Crack 0.2 works with LLVM 2.7, and the forthcoming Crack 0.2.1 release -builds on LLVM 2.8.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="DresdenTM">Dresden TM Compiler (DTMC)</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://tm.inf.tu-dresden.de">DTMC</a> provides support for -Transactional Memory, which is an easy-to-use and efficient way to synchronize -accesses to shared memory. Transactions can contain normal C/C++ code (e.g., -<code>__transaction { list.remove(x); x.refCount--; }</code>) and will be executed -virtually atomically and isolated from other transactions.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="Kai">Kai Programming Language</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://www.oriontransfer.co.nz/research/kai">Kai</a> (Japanese 会 for -meeting/gathering) is an experimental interpreter that provides a highly -extensible runtime environment and explicit control over the compilation -process. Programs are defined using nested symbolic expressions, which are all -parsed into first-class values with minimal intrinsic semantics. Kai can -generate optimised code at run-time (using LLVM) in order to exploit the nature -of the underlying hardware and to integrate with external software libraries. -It is a unique exploration into world of dynamic code compilation, and the -interaction between high level and low level semantics.</p> - -</div> - -<!--=========================================================================--> -<div class="doc_subsection"> -<a name="OSL">OSL: Open Shading Language</a> -</div> - -<div class="doc_text"> -<p> -<a href="http://code.google.com/p/openshadinglanguage/">OSL</a> is a shading -language designed for use in physically based renderers and in particular -production rendering. By using LLVM instead of the interpreter, it was able to -meet its performance goals (>= C-code) while retaining the benefits of -runtime specialization and a portable high-level language. -</p> - -</div> <!-- *********************************************************************** --> <div class="doc_section"> - <a name="whatsnew">What's New in LLVM 2.8?</a> + <a name="whatsnew">What's New in LLVM 2.9?</a> </div> <!-- *********************************************************************** --> @@ -607,19 +315,9 @@ in this section. <div class="doc_text"> -<p>LLVM 2.8 includes several major new capabilities:</p> +<p>LLVM 2.9 includes several major new capabilities:</p> <ul> -<li>As mentioned above, <a href="#libc++">libc++</a> and <a - href="#lldb">LLDB</a> are major new additions to the LLVM collective.</li> -<li>LLVM 2.8 now has pretty decent support for debugging optimized code. You - should be able to reliably get debug info for function arguments, assuming - that the value is actually available where you have stopped.</li> -<li>A new 'llvm-diff' tool is available that does a semantic diff of .ll - files.</li> -<li>The <a href="#mc">MC subproject</a> has made major progress in this release. - Direct .o file writing support for darwin/x86[-64] is now reliable and - support for other targets and object file formats are in progress.</li> </ul> </div> @@ -634,19 +332,6 @@ in this section. expose new optimization opportunities:</p> <ul> -<li>The <a href="LangRef.html#int_libc">memcpy, memmove, and memset</a> - intrinsics now take address space qualified pointers and a bit to indicate - whether the transfer is "<a href="LangRef.html#volatile">volatile</a>" or not. -</li> -<li>Per-instruction debug info metadata is much faster and uses less memory by - using the new DebugLoc class.</li> -<li>LLVM IR now has a more formalized concept of "<a - href="LangRef.html#trapvalues">trap values</a>", which allow the optimizer - to optimize more aggressively in the presence of undefined behavior, while - still producing predictable results.</li> -<li>LLVM IR now supports two new <a href="LangRef.html#linkage">linkage - types</a> (linker_private_weak and linker_private_weak_def_auto) which map - onto some obscure MachO concepts.</li> </ul> </div> @@ -662,30 +347,7 @@ expose new optimization opportunities:</p> release includes a few major enhancements and additions to the optimizers:</p> <ul> -<li>As mentioned above, the optimizer now has support for updating debug - information as it goes. A key aspect of this is the new <a - href="SourceLevelDebugging.html#format_common_value">llvm.dbg.value</a> - intrinsic. This intrinsic represents debug info for variables that are - promoted to SSA values (typically by mem2reg or the -scalarrepl passes).</li> - -<li>The JumpThreading pass is now much more aggressive about implied value - relations, allowing it to thread conditions like "a == 4" when a is known to - be 13 in one of the predecessors of a block. It does this in conjunction - with the new LazyValueInfo analysis pass.</li> -<li>The new RegionInfo analysis pass identifies single-entry single-exit regions - in the CFG. You can play with it with the "opt -regions -analyze" or - "opt -view-regions" commands.</li> -<li>The loop optimizer has significantly improved strength reduction and analysis - capabilities. Notably it is able to build on the trap value and signed - integer overflow information to optimize <= and >= loops.</li> -<li>The CallGraphSCCPassManager now has some basic support for iterating within - an SCC when a optimizer devirtualizes a function call. This allows inlining - through indirect call sites that are devirtualized by store-load forwarding - and other optimizations.</li> -<li>The new <A href="Passes.html#loweratomic">-loweratomic</a> pass is available - to lower atomic instructions into their non-atomic form. This can be useful - to optimize generic code that expects to run in a single-threaded - environment.</li> +TBAA. </ul> <!-- @@ -709,26 +371,8 @@ of problems in the realm of assembly, disassembly, object file format handling, and a number of other related areas that CPU instruction-set level tools work in.</p> -<p>The MC subproject has made great leaps in LLVM 2.8. For example, support for - directly writing .o files from LLC (and clang) now works reliably for - darwin/x86[-64] (including inline assembly support) and the integrated - assembler is turned on by default in Clang for these targets. This provides - improved compile times among other things.</p> - <ul> -<li>The entire compiler has converted over to using the MCStreamer assembler API - instead of writing out a .s file textually.</li> -<li>The "assembler parser" is far more mature than in 2.7, supporting a full - complement of directives, now supports assembler macros, etc.</li> -<li>The "assembler backend" has been completed, including support for relaxation - relocation processing and all the other things that an assembler does.</li> -<li>The MachO file format support is now fully functional and works.</li> -<li>The MC disassembler now fully supports ARM and Thumb. ARM assembler support - is still in early development though.</li> -<li>The X86 MC assembler now supports the X86 AES and AVX instruction set.</li> -<li>Work on ELF and COFF object files and ARM target support is well underway, - but isn't useful yet in LLVM 2.8. Please contact the llvmdev mailing list - if you're interested in this.</li> +ELF/COFF support? </ul> <p>For more information, please see the <a @@ -751,58 +395,8 @@ infrastructure, which allows us to implement more aggressive algorithms and make it run faster:</p> <ul> -<li>The clang/gcc -momit-leaf-frame-pointer argument is now supported.</li> -<li>The clang/gcc -ffunction-sections and -fdata-sections arguments are now - supported on ELF targets (like GCC).</li> -<li>The MachineCSE pass is now tuned and on by default. It eliminates common - subexpressions that are exposed when lowering to machine instructions.</li> -<li>The "local" register allocator was replaced by a new "fast" register - allocator. This new allocator (which is often used at -O0) is substantially - faster and produces better code than the old local register allocator.</li> -<li>A new LLC "-regalloc=default" option is available, which automatically - chooses a register allocator based on the -O optimization level.</li> -<li>The common code generator code was modified to promote illegal argument and - return value vectors to wider ones when possible instead of scalarizing - them. For example, <3 x float> will now pass in one SSE register - instead of 3 on X86. This generates substantially better code since the - rest of the code generator was already expecting this.</li> -<li>The code generator uses a new "COPY" machine instruction. This speeds up - the code generator and eliminates the need for targets to implement the - isMoveInstr hook. Also, the copyRegToReg hook was renamed to copyPhysReg - and simplified.</li> -<li>The code generator now has a "LocalStackSlotPass", which optimizes stack - slot access for targets (like ARM) that have limited stack displacement - addressing.</li> -<li>A new "PeepholeOptimizer" is available, which eliminates sign and zero - extends, and optimizes away compare instructions when the condition result - is available from a previous instruction.</li> -<li>Atomic operations now get legalized into simpler atomic operations if not - natively supported, easing the implementation burden on targets.</li> -<li>We have added two new bottom-up pre-allocation register pressure aware schedulers: -<ol> -<li>The hybrid scheduler schedules aggressively to minimize schedule length when registers are available and avoid overscheduling in high pressure situations.</li> -<li>The instruction-level-parallelism scheduler schedules for maximum ILP when registers are available and avoid overscheduling in high pressure situations.</li> -</ol></li> -<li>The tblgen type inference algorithm was rewritten to be more consistent and - diagnose more target bugs. If you have an out-of-tree backend, you may - find that it finds bugs in your target description. This support also - allows limited support for writing patterns for instructions that return - multiple results (e.g. a virtual register and a flag result). The - 'parallel' modifier in tblgen was removed, you should use the new support - for multiple results instead.</li> -<li>A new (experimental) "-rendermf" pass is available which renders a - MachineFunction into HTML, showing live ranges and other useful - details.</li> -<li>The new SubRegIndex tablegen class allows subregisters to be indexed - symbolically instead of numerically. If your target uses subregisters you - will need to adapt to use SubRegIndex when you upgrade to 2.8.</li> <!-- SplitKit --> - -<li>The -fast-isel instruction selection path (used at -O0 on X86) was rewritten - to work bottom-up on basic blocks instead of top down. This makes it - slightly faster (because the MachineDCE pass is not needed any longer) and - allows it to generate better code in some cases.</li> - +FastISel for ARM. </ul> </div> @@ -816,42 +410,6 @@ it run faster:</p> </p> <ul> -<li>The X86 backend now supports holding X87 floating point stack values - in registers across basic blocks, dramatically improving performance of code - that uses long double, and when targeting CPUs that don't support SSE.</li> - -<li>The X86 backend now uses a SSEDomainFix pass to optimize SSE operations. On - Nehalem ("Core i7") and newer CPUs there is a 2 cycle latency penalty on - using a register in a different domain than where it was defined. This pass - optimizes away these stalls.</li> - -<li>The X86 backend now promotes 16-bit integer operations to 32-bits when - possible. This avoids 0x66 prefixes, which are slow on some - microarchitectures and bloat the code on all of them.</li> - -<li>The X86 backend now supports the Microsoft "thiscall" calling convention, - and a <a href="LangRef.html#callingconv">calling convention</a> to support - <a href="#GHC">ghc</a>.</li> - -<li>The X86 backend supports a new "llvm.x86.int" intrinsic, which maps onto - the X86 "int $42" and "int3" instructions.</li> - -<li>At the IR level, the <2 x float> datatype is now promoted and passed - around as a <4 x float> instead of being passed and returned as an MMX - vector. If you have a frontend that uses this, please pass and return a - <2 x i32> instead (using bitcasts).</li> - -<li>When printing .s files in verbose assembly mode (the default for clang -S), - the X86 backend now decodes X86 shuffle instructions and prints human - readable comments after the most inscrutable of them, e.g.: - -<pre> - insertps $113, %xmm3, %xmm0 <i># xmm0 = zero,xmm0[1,2],xmm3[1]</i> - unpcklps %xmm1, %xmm0 <i># xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1]</i> - pshufd $1, %xmm1, %xmm1 <i># xmm1 = xmm1[1,0,0,0]</i> -</pre> -</li> - </ul> </div> @@ -866,72 +424,6 @@ it run faster:</p> </p> <ul> -<li>The ARM backend now optimizes tail calls into jumps.</li> -<li>Scheduling is improved through the new list-hybrid scheduler as well - as through better modeling of structural hazards.</li> -<li><a href="LangRef.html#int_fp16">Half float</a> instructions are now - supported.</li> -<li>NEON support has been improved to model instructions which operate onto - multiple consecutive registers more aggressively. This avoids lots of - extraneous register copies.</li> -<li>The ARM backend now uses a new "ARMGlobalMerge" pass, which merges several - global variables into one, saving extra address computation (all the global - variables can be accessed via same base address) and potentially reducing - register pressure.</li> - -<li>The ARM backend has received many minor improvements and tweaks which lead - to substantially better performance in a wide range of different scenarios. -</li> - -<li>The ARM NEON intrinsics have been substantially reworked to reduce - redundancy and improve code generation. Some of the major changes are: - <ol> - <li> - All of the NEON load and store intrinsics (llvm.arm.neon.vld* and - llvm.arm.neon.vst*) take an extra parameter to specify the alignment in bytes - of the memory being accessed. - </li> - <li> - The llvm.arm.neon.vaba intrinsic (vector absolute difference and - accumulate) has been removed. This operation is now represented using - the llvm.arm.neon.vabd intrinsic (vector absolute difference) followed by a - vector add. - </li> - <li> - The llvm.arm.neon.vabdl and llvm.arm.neon.vabal intrinsics (lengthening - vector absolute difference with and without accumulation) have been removed. - They are represented using the llvm.arm.neon.vabd intrinsic (vector absolute - difference) followed by a vector zero-extend operation, and for vabal, - a vector add. - </li> - <li> - The llvm.arm.neon.vmovn intrinsic has been removed. Calls of this intrinsic - are now replaced by vector truncate operations. - </li> - <li> - The llvm.arm.neon.vmovls and llvm.arm.neon.vmovlu intrinsics have been - removed. They are now represented as vector sign-extend (vmovls) and - zero-extend (vmovlu) operations. - </li> - <li> - The llvm.arm.neon.vaddl*, llvm.arm.neon.vaddw*, llvm.arm.neon.vsubl*, and - llvm.arm.neon.vsubw* intrinsics (lengthening vector add and subtract) have - been removed. They are replaced by vector add and vector subtract operations - where one (vaddw, vsubw) or both (vaddl, vsubl) of the operands are either - sign-extended or zero-extended. - </li> - <li> - The llvm.arm.neon.vmulls, llvm.arm.neon.vmullu, llvm.arm.neon.vmlal*, and - llvm.arm.neon.vmlsl* intrinsics (lengthening vector multiply with and without - accumulation and subtraction) have been removed. These operations are now - represented as vector multiplications where the operands are either - sign-extended or zero-extended, followed by a vector add for vmlal or a - vector subtract for vmlsl. Note that the polynomial vector multiply - intrinsic, llvm.arm.neon.vmullp, remains unchanged. - </li> - </ol> -</li> - </ul> </div> @@ -944,29 +436,10 @@ it run faster:</p> <div class="doc_text"> <p>If you're already an LLVM user or developer with out-of-tree changes based -on LLVM 2.7, this section lists some "gotchas" that you may run into upgrading +on LLVM 2.8, this section lists some "gotchas" that you may run into upgrading from the previous release.</p> <ul> -<li>The build configuration machinery changed the output directory names. It - wasn't clear to many people that a "Release-Asserts" build was a release build - without asserts. To make this more clear, "Release" does not include - assertions and "Release+Asserts" does (likewise, "Debug" and - "Debug+Asserts").</li> -<li>The MSIL Backend was removed, it was unsupported and broken.</li> -<li>The ABCD, SSI, and SCCVN passes were removed. These were not fully - functional and their behavior has been or will be subsumed by the - LazyValueInfo pass.</li> -<li>The LLVM IR 'Union' feature was removed. While this is a desirable feature - for LLVM IR to support, the existing implementation was half baked and - barely useful. We'd really like anyone interested to resurrect the work and - finish it for a future release.</li> -<li>If you're used to reading .ll files, you'll probably notice that .ll file - dumps don't produce #uses comments anymore. To get them, run a .bc file - through "llvm-dis --show-annotations".</li> -<li>Target triples are now stored in a normalized form, and all inputs from - humans are expected to be normalized by Triple::normalize before being - stored in a module triple or passed to another library.</li> </ul> @@ -974,72 +447,6 @@ from the previous release.</p> <p>In addition, many APIs have changed in this release. Some of the major LLVM API changes are:</p> <ul> -<li>LLVM 2.8 changes the internal order of operands in <a - href="http://llvm.org/doxygen/classllvm_1_1InvokeInst.html"><tt>InvokeInst</tt></a> - and <a href="http://llvm.org/doxygen/classllvm_1_1CallInst.html"><tt>CallInst</tt></a>. - To be portable across releases, please use the <tt>CallSite</tt> class and the - high-level accessors, such as <tt>getCalledValue</tt> and - <tt>setUnwindDest</tt>. -</li> -<li> - You can no longer pass use_iterators directly to cast<> (and similar), - because these routines tend to perform costly dereference operations more - than once. You have to dereference the iterators yourself and pass them in. -</li> -<li> - llvm.memcpy.*, llvm.memset.*, llvm.memmove.* intrinsics take an extra - parameter now ("i1 isVolatile"), totaling 5 parameters, and the pointer - operands are now address-space qualified. - If you were creating these intrinsic calls and prototypes yourself (as opposed - to using Intrinsic::getDeclaration), you can use - UpgradeIntrinsicFunction/UpgradeIntrinsicCall to be portable across releases. -</li> -<li> - SetCurrentDebugLocation takes a DebugLoc now instead of a MDNode. - Change your code to use - SetCurrentDebugLocation(DebugLoc::getFromDILocation(...)). -</li> -<li> - The <tt>RegisterPass</tt> and <tt>RegisterAnalysisGroup</tt> templates are - considered deprecated, but continue to function in LLVM 2.8. Clients are - strongly advised to use the upcoming <tt>INITIALIZE_PASS()</tt> and - <tt>INITIALIZE_AG_PASS()</tt> macros instead. -</li> -<li> - The constructor for the Triple class no longer tries to understand odd triple - specifications. Frontends should ensure that they only pass valid triples to - LLVM. The Triple::normalize utility method has been added to help front-ends - deal with funky triples. -</li> -<li> - The signature of the <tt>GCMetadataPrinter::finishAssembly</tt> virtual - function changed: the <tt>raw_ostream</tt> and <tt>MCAsmInfo</tt> arguments - were dropped. GC plugins which compute stack maps must be updated to avoid - having the old definition overload the new signature. -</li> -<li> - The signature of <tt>MemoryBuffer::getMemBuffer</tt> changed. Unfortunately - calls intended for the old version still compile, but will not work correctly, - leading to a confusing error about an invalid header in the bitcode. -</li> - -<li> - Some APIs were renamed: - <ul> - <li>llvm_report_error -> report_fatal_error</li> - <li>llvm_install_error_handler -> install_fatal_error_handler</li> - <li>llvm::DwarfExceptionHandling -> llvm::JITExceptionHandling</li> - <li>VISIBILITY_HIDDEN -> LLVM_LIBRARY_VISIBILITY</li> - </ul> -</li> - -<li> - Some public headers were renamed: - <ul> - <li><tt>llvm/Assembly/AsmAnnotationWriter.h</tt> was renamed - to <tt>llvm/Assembly/AssemblyAnnotationWriter.h</tt> - </li> - </ul> </ul> </div> @@ -1057,30 +464,6 @@ mainline, but may also impact users who leverage the LLVM build infrastructure or are interested in LLVM qualification.</p> <ul> - <li>The default for <tt>make check</tt> is now to use - the <a href="http://llvm.org/cmds/lit.html">lit</a> testing tool, which is - part of LLVM itself. You can use <tt>lit</tt> directly as well, or use - the <tt>llvm-lit</tt> tool which is created as part of a Makefile or CMake - build (and knows how to find the appropriate tools). See the <tt>lit</tt> - documentation and the <a href="http://blog.llvm.org/2009/12/lit-it.html">blog - post</a>, and <a href="http://llvm.org/bugs/show_bug.cgi?id=5217">PR5217</a> - for more information.</li> - - <li>The LLVM <tt>test-suite</tt> infrastructure has a new "simple" test format - (<tt>make TEST=simple</tt>). The new format is intended to require only a - compiler and not a full set of LLVM tools. This makes it useful for testing - released compilers, for running the test suite with other compilers (for - performance comparisons), and makes sure that we are testing the compiler as - users would see it. The new format is also designed to work using reference - outputs instead of comparison to a baseline compiler, which makes it run much - faster and makes it less system dependent.</li> - - <li>Significant progress has been made on a new interface to running the - LLVM <tt>test-suite</tt> (aka the LLVM "nightly tests") using - the <a href="http://llvm.org/docs/lnt">LNT</a> infrastructure. The LNT - interface to the <tt>test-suite</tt> brings significantly improved reporting - capabilities for monitoring the correctness and generated code quality - produced by LLVM over time.</li> </ul> </div> @@ -1114,10 +497,11 @@ components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p> <ul> -<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, SystemZ +<li>The Alpha, Blackfin, CellSPU, MicroBlaze, MSP430, MIPS, PTX, SystemZ and XCore backends are experimental.</li> <li><tt>llc</tt> "<tt>-filetype=obj</tt>" is experimental on all targets - other than darwin-i386 and darwin-x86_64.</li> + other than darwin-i386 and darwin-x86_64. FIXME: Not true on ELF anymore?</li> + </ul> </div> |