[llvm-commits] [llvm] r127399 - /llvm/trunk/docs/ReleaseNotes.html
Chris Lattner
sabre at nondot.org
Wed Mar 9 23:43:44 PST 2011
Author: lattner
Date: Thu Mar 10 01:43:44 2011
New Revision: 127399
URL: http://llvm.org/viewvc/llvm-project?rev=127399&view=rev
Log:
rip out llvm 2.8 release notes to make room for llvm 2.9 notes.
Modified:
llvm/trunk/docs/ReleaseNotes.html
Modified: llvm/trunk/docs/ReleaseNotes.html
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/ReleaseNotes.html?rev=127399&r1=127398&r2=127399&view=diff
==============================================================================
--- llvm/trunk/docs/ReleaseNotes.html (original)
+++ llvm/trunk/docs/ReleaseNotes.html Thu Mar 10 01:43:44 2011
@@ -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 @@
<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 @@
<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 @@
CorrelatedValuePropagation
-->
- <!-- Announcement, lldb, libc++ -->
-
-
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="subproj">Sub-project Status Update</a>
@@ -91,7 +85,7 @@
<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 @@
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>
+<p>In the LLVM 2.9 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>
+<ul>
+</ul>
</div>
<!--=========================================================================-->
@@ -156,8 +131,7 @@
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 @@
</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 @@
</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 @@
<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 @@
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 @@
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 @@
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 @@
<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>
-
-</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>
-
+ projects that have already been updated to work with LLVM 2.9.</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 ä¼ 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 @@
<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 @@
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 @@
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 @@
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 @@
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 @@
</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 @@
</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 @@
<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 @@
<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 @@
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 @@
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>
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