<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link rel="stylesheet" href="llvm.css" type="text/css">
- <title>LLVM 2.7 Release Notes</title>
+ <title>LLVM 2.8 Release Notes</title>
</head>
<body>
-<div class="doc_title">LLVM 2.7 Release Notes</div>
+<div class="doc_title">LLVM 2.8 Release Notes</div>
<img align=right src="http://llvm.org/img/DragonSmall.png"
- width="136" height="136">
+ 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>
- <li><a href="#externalproj">External Projects Using LLVM 2.7</a></li>
- <li><a href="#whatsnew">What's New in LLVM 2.7?</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="GettingStarted.html">Installation Instructions</a></li>
- <li><a href="#portability">Portability and Supported Platforms</a></li>
<li><a href="#knownproblems">Known Problems</a></li>
<li><a href="#additionalinfo">Additional Information</a></li>
</ol>
</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/2.7/docs/ReleaseNotes.html">LLVM 2.7
+Release Notes</a>.</h1>
+-->
<!-- *********************************************************************** -->
<div class="doc_section">
<div class="doc_text">
<p>This document contains the release notes for the LLVM Compiler
-Infrastructure, release 2.7. Here we describe the status of LLVM, including
+Infrastructure, release 2.8. 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>
current one. To see the release notes for a specific release, please see the
<a href="http://llvm.org/releases/">releases page</a>.</p>
-
-<p>FIXME: llvm.org moved to new server, mention new logo, Ted and Doug new code
- owners, web page in llvm-www repos.</p>
-
</div>
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, GEPSplitterPass
- MSIL backend?
- lib/Transforms/Utils/SSI.cpp -> ABCD depends on it.
+ GEPSplitterPass
-->
-<!-- Features that need text if they're finished for 2.7:
- gcc plugin.
+<!-- Features that need text if they're finished for 2.9:
+ 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>
+ TBAA
+ CorrelatedValuePropagation
-->
-
- <!-- 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.
- -->
+
+ <!-- Announcement, lldb, libc++ -->
<!-- *********************************************************************** -->
<div class="doc_section">
<div class="doc_text">
<p>
-The LLVM 2.7 distribution currently consists of code from the core LLVM
+The LLVM 2.8 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
<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, Objective-C, C++ and Objective-C++ on x86
+(32- and 64-bit), and for darwin-arm targets.</p>
-<p>In the LLVM 2.7 time-frame, the Clang team has made many improvements:</p>
+<p>In the LLVM 2.8 time-frame, the Clang team has made many improvements:</p>
<ul>
-<li>FIXME: C++! Include a link to cxx_compatibility.html</li>
-
-<li>FIXME: Static Analyzer improvements?</li>
-
-<li>CIndex API and Python bindings: Clang now includes a C API as part of the
-CIndex library. Although we make 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 includings an 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 a beta quality ARM compiler.</li>
+<li>Surely these guys have done something</li>
</ul>
</div>
<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>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 sprouted legs and...</p>
+<p>In the LLVM 2.8 time-frame,
+</p>
</div>
implementation of the CLI) using LLVM for static and just-in-time
compilation.</p>
-<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>
+<p>With the release of LLVM 2.8, ...</p>
-<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>
<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 2.8:
+
+Soft float support
+</p>
</div>
</p>
<p>
-The first dragonegg release will occur shortly after llvm-2.7 is released.
+2.8 status here.
</p>
</div>
<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>2.8 status here</p>
</div>
-
-<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="externalproj">External Open Source Projects Using LLVM 2.7</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 2.7.</p>
-</div>
-
-
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="Rubinius">Rubinius</a>
-</div>
-
-<div class="doc_text">
-Need update.
-<!--
-<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>
+<a name="lldb">LLDB: Low Level Debugger</a>
</div>
<div class="doc_text">
+<p>
+<a href="http://lldb.llvm.org/">LLDB</a> is</p>
<p>
-Need update.
-<!--
-<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>
+2.8 status here.
+</p>
</div>
-
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="pure">Pure</a>
+<a name="libc++">libc++: C++ Standard Library</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 0.43 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="ldc">LLVM D Compiler</a>
-</div>
+<a href="http://libc++.llvm.org/">libc++</a> is</p>
-<div class="doc_text">
<p>
-Need update.
-<!--
-<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.-->
</p>
-</div>
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="RoadsendPHP">Roadsend PHP</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.
+2.8 status here.
</p>
-</div>
-<!--=========================================================================-->
-<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="llvm-lua">llvm-lua</a>
+<!-- *********************************************************************** -->
+<div class="doc_section">
+ <a name="externalproj">External Open Source Projects Using LLVM 2.8</a>
</div>
+<!-- *********************************************************************** -->
<div class="doc_text">
-<p>
-Need update.
-<!--
-<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>
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="icedtea">IcedTea Java Virtual Machine Implementation</a>
-</div>
-
-<div class="doc_text">
-<p>
-Need update.
-<!--
-<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>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 class="doc_section">
+ <a name="whatsnew">What's New in LLVM 2.8?</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>
+<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="safecode">SAFECode Compiler</a>
-</div>
-
-<div class="doc_text">
-<p>
-<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>
+<a name="orgchanges">LLVM Community Changes</a>
</div>
-
-<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="whatsnew">What's New in LLVM 2.7?</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>In addition to changes to the code, between LLVM 2.7 and 2.8, a number of
+organization changes have happened:
</p>
+<ul>
+<li>libc++ and lldb are new</li>
+</ul>
</div>
<!--=========================================================================-->
<div class="doc_text">
-<p>LLVM 2.7 includes several major new capabilities:</p>
+<p>LLVM 2.8 includes several major new capabilities:</p>
<ul>
-<li>...</li>
+<li>atomic lowering pass.</li>
+<li>RegionInfo pass: opt -regions analyze" or "opt -view-regions".
+<!-- Tobias Grosser --></li>
+<li>ARMGlobalMerge: <!-- Anton --> </li>
+<li>llvm-diff</li>
</ul>
-Extensible metadata solid.
-
-Debug info improvements: using metadata instead of llvm.dbg global variables.
-This brings several enhancements including improved compile times.
-
-New instruction selector.
-GHC Haskell ABI/ calling conv support.
-Pre-Alpha support for unions in IR.
-New InlineHint and StackAlignment function attributes
-Code generator MC'ized except for debug info and EH.
-New SCEV AA pass: -scev-aa
-Inliner reuses arrays allocas when inlining multiple callers to reduce stack usage.
-MC encoding and disassembler apis.
-Optimal Edge Profiling?
-Instcombine is now a library, has its own IRBuilder to simplify itself.
-New llvm/Support/Regex.h API. FileCheck now does regex's
-Many subtle pointer invalidation bugs in Callgraph have been fixed and it now uses asserting value handles.
-MC Disassembler (with blog post), MCInstPrinter. Many X86 backend and AsmPrinter simplifications
-Various tools like llc and opt now read either .ll or .bc files as input.
-Malloc and free instructions got removed, along with LowerAllocations pass.
-compiler-rt support for ARM.
-completely llvm-gcc NEON support.
-Can transcode from GAS to intel syntax with "llvm-mc foo.s -output-asm-variant=1"
-JIT debug information with GDB 7.0
-New CodeGen Level CSE
-CMake can now run tests, what other improvements?
-ARM/Thumb using reg scavenging for stack object address materialization (PEI).
-New SSAUpdater and MachineSSAUpdater classes for unstructured ssa updating,
- changed jump threading, GVN, etc to use it which simplified them and speed
- them up.
-Combiner-AA improvements, why not on by default?
-Pre-regalloc tail duplication
-x86 sibcall / tailcall optimization in CCC mode.
-New LSR with "full strength reduction" mode. Description?
-Codegen level OptimizeExtsPass pass, takes advantage of x86 subregs.
-Better code size analysis in loop unswitch, inliner code split out to a new
- CodeMetrics class for reuse.
-The ARM backend now has good support for ARMv4 backend (tested on StrongARM
- hardware), previously only supported ARMv4T and newer.
-Half-float support in APFloat
-Indirect branch + address of label (blog post), particularly useful for interpreters.
-Many changes to the pass ordering for improved optimization effectiveness.
-BasicAA improved to be less dependent on "type safe" pointers, it can now look
- through bitcasts more aggressively.
-GVN PHI Translation improvements. blog post: http://blog.llvm.org/2009/12/advanced-topics-in-redundant-load.html
-llvm.objectsize.
-MachineSSAUpdater.h
-PostRA scheduler for X86?
-llvm.dbg.value, not being used by default though, more in 2.8. Many improvements to debug info
-Support for the GCC option -fno-schedule-insns
-non-temporal load/store
-libllvm2.7.so?? configure with --enable-shared
-dbgs() and -debug-buffer-size=N
-New MicroBlaze backend. http://en.wikipedia.org/wiki/MicroBlaze
-XMM subreg modeling for extraction of the low element.
-
-
-Opt now works conservatively if no target data is set (is this fully working?)
-Target data now has notion of 'native' integer data types which optimizations can use.
-ARM backend generates instructions in unified assembly syntax.
-New Analysis/InstructionSimplify.h interface for simplifying instructions that don't exist.
-Jump threading is now much more aggressive at simplifying correlated
- conditionals and threading blocks with otherwise complex logic. CondProp pass
- removed (functionality merged into jump threading).
-X86 and XCore supports returning arbitrary return values, returning too many values is
- supported by returning through a hidden pointer.
-verbose-asm now produces information about spill slots and loop nests
-
-
-Defaults to RTTI off (smaller code size!), packagers should build with make REQUIRE_RTTI=1.
-AndersAA got removed
-PredSimplify, LoopVR, GVNPRE, RSProfiling (random sampling profiling) got removed.
-LLVM command line tools now overwrite their output, before they would only do this with -f.
-DOUT removed, use DEBUG(errs() instead.
-Much stuff converted to use raw_ostream instead of std::ostream.
-TargetAsmInfo renamed to MCAsmInfo
-llvm/ADT/iterator.h gone.
-
-
</div>
<!--=========================================================================-->
expose new optimization opportunities:</p>
<ul>
-<li>...</li>
+
+<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, resort to <tt>CallSite</tt> 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.* (and possibly other?) intrinsics
+ take an extra parameter now (i1 isVolatile), totaling 5 parameters.
+ If you were creating these intrinsic calls and prototypes yourself (as opposed
+ to using Intrinsic::getDeclaration), you can use UpgradeIntrinsicFunction/UpgradeIntrinsicCall
+ to be portable accross releases.
+ Note that you cannot use Intrinsic::getDeclaration() in a backwards compatible
+ way (needs 2/3 types now, in 2.7 it needed just 1).
+</li>
+<li>
+ SetCurrentDebugLocation takes a DebugLoc now instead of a MDNode.
+ Change your code to use
+ SetCurrentDebugLocation(DebugLoc::getFromDILocation(...)).
+</li>
+<li>
+ VISIBILITY_HIDDEN is gone.
+</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>
+ SMDiagnostic takes different parameters now. //FIXME: how to upgrade?
+</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>
+ Some APIs got 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>
+ </ul>
+</li>
</ul>
</div>
<ul>
-<li>...</li>
+<li></li>
</ul>
-<p>Also, -anders-aa was removed</p>
-
</div>
<div class="doc_text">
<ul>
-<li>The JIT now <a
-href="http://llvm.org/viewvc/llvm-project?view=rev&revision=85295">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>
+<li></li>
+
</ul>
</div>
it run faster:</p>
<ul>
-
-<li>...</li>
+<li>MachO writer works.</li>
</ul>
</div>
</p>
<ul>
-
-<li>...</li>
+<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 targetting CPUs that don't support SSE.</li>
</ul>
</div>
-<!--=========================================================================-->
-<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>
<ul>
-<li>...</li>
-</ul>
-
-
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="OtherTarget">Other Target Specific Improvements</a>
-</div>
-
-<div class="doc_text">
-<p>New features of other targets include:
-</p>
+<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 accumlation) 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>
-<ul>
-<li>...</li>
</ul>
-
</div>
<!--=========================================================================-->
</p>
<ul>
-<li>...</li>
+<li></li>
</ul>
<p>Other miscellaneous features include:</p>
<ul>
-<li>...</li>
+<li></li>
</ul>
</div>
<div class="doc_text">
<p>If you're already an LLVM user or developer with out-of-tree changes based
-on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading
+on LLVM 2.7, this section lists some "gotchas" that you may run into upgrading
from the previous release.</p>
<ul>
-<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>
+<li>.ll file doesn't produce #uses comments anymore, to get them, run a .bc file
+ through "llvm-dis --show-annotations".</li>
+<li>MSIL Backend removed.</li>
+<li>ABCD and SSI passes removed.</li>
+<li>'Union' LLVM IR feature removed.</li>
</ul>
-
<p>In addition, many APIs have changed in this release. Some of the major LLVM
API changes are:</p>
<ul>
-<li><tt>ModuleProvider</tt> has been <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
-<tt>getLazyBitcodeModule</tt>, and pass their <tt>Module</tt> to
-functions that used to accept <tt>ModuleProvider</tt>. Clients who
-wrote their own <tt>ModuleProvider</tt>s will need to derive from
-<tt>GVMaterializer</tt> instead and use
-<tt>Module::setMaterializer</tt> to attach it to a
-<tt>Module</tt>.</li>
-
-<li><tt>GhostLinkage</tt> has given up the ghost.
-<tt>GlobalValue</tt>s that have not yet been read from their backing
-storage have the same linkage they will have after being read in.
-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>
</ul>
</div>
-
-<!-- *********************************************************************** -->
-<div class="doc_section">
- <a name="portability">Portability and Supported Platforms</a>
-</div>
-<!-- *********************************************************************** -->
-
-<div class="doc_text">
-
-<p>LLVM is known to work on the following platforms:</p>
-
-<ul>
-<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
- 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 x86 and AMD64 machines running Solaris 10, OpenSolaris 0906.</li>
-<li>Alpha-based machines running Debian GNU/Linux.</li>
-</ul>
-
-<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
-to the machine and operating system on which it is built. However, minor
-porting may be required to get LLVM to work on new platforms. We welcome your
-portability patches and reports of successful builds or error messages.</p>
-
-</div>
-
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="knownproblems">Known Problems</a>
href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
there isn't already one.</p>
-<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>.
-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>
<!-- ======================================================================= -->
href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
<ul>
-<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
+<li>The Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
backends are experimental.</li>
-<li>The <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>
+<li><tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
+ supported value for this option. XXX Update me</li>
</ul>
</div>
all <a href="http://llvm.org/PR879">inline assembly that uses the X86
floating point stack</a>. It supports the 'f' and 't' constraints, but not
'u'.</li>
- <li>The X86 backend generates inefficient floating point code when configured
- 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>
<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>
<div class="doc_text">
+<p>The C backend has numerous problems and is not being actively maintained.
+Depending on it for anything serious is not advised.</p>
+
<ul>
<li><a href="http://llvm.org/PR802">The C backend has only basic support for
inline assembly code</a>.</li>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="c-fe">Known problems with the llvm-gcc C and C++ front-end</a>
+ <a name="llvm-gcc">Known problems with the llvm-gcc front-end</a>
</div>
<div class="doc_text">
-<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
- 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>
+<p>llvm-gcc is generally very stable for the C family of languages. 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
+ supported on some targets (these are used when you take the address of a
+ nested function).</p>
-</div>
+<p>Fortran support generally works, but there are still several unresolved bugs
+ in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
+ tools/gfortran component for details. Note that llvm-gcc is missing major
+ Fortran performance work in the frontend and library that went into GCC after
+ 4.2. If you are interested in Fortran, we recommend that you consider using
+ <a href="#dragonegg">dragonegg</a> instead.</p>
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
-</div>
-
-<div class="doc_text">
-<ul>
-<li>Fortran support generally works, but there are still several unresolved bugs
- in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
- tools/gfortran component for details.</li>
-</ul>
-</div>
-
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="ada-fe">Known problems with the llvm-gcc Ada front-end</a>
-</div>
-
-<div class="doc_text">
-The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
-technology, and problems should be expected.
+<p>The llvm-gcc 4.2 Ada compiler has basic functionality. However, this is not a
+mature technology, and problems should be expected. For example:</p>
<ul>
<li>The Ada front-end currently only builds on X86-32. This is mainly due
to lack of trampoline support (pointers to nested functions) on other platforms.
projects / oota-llvm.git / blobdiff