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- <title>LLVM 2.1 Release Notes</title>
+ <title>LLVM 2.2 Release Notes</title>
</head>
<body>
-<div class="doc_title">LLVM 2.1 Release Notes</div>
+<div class="doc_title">LLVM 2.2 Release Notes</div>
<ol>
<li><a href="#intro">Introduction</a></li>
<p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
</div>
+<h1><font color="red">THIS IS A WORK IN PROGRESS FOR THE LLVM 2.2
+RELEASE</font</h1>
+
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="intro">Introduction</a>
<div class="doc_text">
<p>This document contains the release notes for the LLVM compiler
-infrastructure, release 2.1. Here we describe the status of LLVM, including
+infrastructure, release 2.2. Here we describe the status of LLVM, including
major improvements from the previous release and any known problems. All LLVM
releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
releases web site</a>.</p>
<div class="doc_text">
-<p>This is the twelfth public release of the LLVM Compiler Infrastructure.
-It includes many features and refinements from LLVM 2.0.</p>
+<p>This is the thirteenth public release of the LLVM Compiler Infrastructure.
+It includes many features and refinements from LLVM 2.1.</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="frontends">New Frontends</a>
+<a name="frontends">llvm-gcc 4.0, llvm-gcc 4.2, and clang</a>
</div>
<div class="doc_text">
-<p>LLVM 2.1 brings two new beta C front-ends. First, Duncan, Anton and Devang
-start syncing up llvm-gcc with GCC 4.2, yielding "llvm-gcc 4.2" (creative,
-huh?). llvm-gcc 4.2 has the promise to bring much better FORTRAN and Ada
-support to LLVM as well as features like atomic builtins, OpenMP, and many other
-things. Check it out!</p>
+<p>LLVM 2.2 fully supports both the llvm-gcc 4.0 and llvm-gcc 4.2 front-ends (in
+LLVM 2.1, llvm-gcc 4.2 was beta). Since LLVM 2.1, the llvm-gcc 4.2 front-end
+has made leaps and bounds and is now at least as good as 4.0 in virtually every
+area, and is better in several areas (for example, exception handling
+correctness). We strongly recommend that you migrate from llvm-gcc 4.0 to
+llvm-gcc 4.2 in this release cycle because <b>LLVM 2.2 is the last release
+that will support llvm-gcc 4.0</b>: LLVM 2.3 will only support the llvm-gcc
+4.2 front-end.</p>
-<p>Second, LLVM now includes its own native C and Objective-C front-end (C++ is
-in progress, but is not very far along) code named "<a
-href="http://clang.llvm.org/">clang</a>". This front-end has a number of great
-features, primarily aimed at source-level analysis and speeding up compile-time.
-At this point though, the LLVM Code Generator component is still very early in
-development, so it's mostly useful for people looking to build source-level
-analysis tools or source-to-source translators.</p>
+<p>The <a href="http://clang.llvm.org/">clang project</a> is an effort to build
+a set of new 'llvm native' front-end technologies for the LLVM optimizer
+and code generator. Currently, its C and Objective-C support is maturing
+nicely, and it has advanced source-to-source analysis and transformation
+capabilities. If you are interested in building source-level tools for C and
+Objective-C (and eventually C++), you should take a look. However, note that
+clang is not an official part of the LLVM 2.2 release. If you are interested in
+this project, please see the web site.</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="optimizer">Optimizer Improvements</a>
+<a name="majorfeatures">Major New Features</a>
</div>
<div class="doc_text">
-<p>Some of the most noticable improvements this release have been in the
-optimizer, speeding it up and making it more aggressive</p>
+<p>Dale contributed full support for long double on x86/x86-64 (where it is 80
+bits) and on Darwin PPC/PPC64 (where it is 128 bits).</p>
-<ul>
+<p>Ada, gfortran</p>
-<li>Owen DSE and MemDep analysis</li>
-<li>Owen GVN</li>
-<li>Owen GVN-PRE, not in llvm-gcc</li>
-<li>Devang merged ETForest and DomTree into a single easier to use data
-structure.</li>
-<li>Nick Lewycky improved loop trip count analysis to handle many more common
-cases.</li>
+<p>
+debug improvements -O0
+EH.
-</ul>
+Gordon: GC Revamp. docs/GarbageCollection.html
+
+Kaleidescope: docs/tutorial
+
+Gordon: C and Ocaml Bindings
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="codegen">Code Generator Improvements</a>
+<a name="optimizer">Optimizer Improvements</a>
</div>
<div class="doc_text">
-<p>foo</p>
+<p>Some of the most noticable feature improvements this release have been in the
+optimizer, speeding it up and making it more aggressive. For example:</p>
<ul>
-<li>Dale finished up the Tail Merging optimization in the code generator,
-enabling it by default. This produces smaller code that is also faster in some
-cases.</li>
+<li>Daniel Berlin and (Curtis?) rewrote Andersen's alias analysis (which is not
+enabled by default) to be several orders of magnitude faster, implmented Offline
+Variable Substitution.</li>
+
+
+Devang: LoopIndexSplit is enabled by default.
+</ul>
+
+</div>
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="codegen">Code Generator Improvements</a>
+</div>
-<li>Dan Gohman changed the way we represent vectors before legalization,
-significantly simplifying the SelectionDAG representation for these and making
-the code generator faster for vector code.</li>
+<div class="doc_text">
-<li>Evan remat rewrite (coalesced intervals + folding of remat'd loads) and
-live intervals improvements.</li>
+<p>foci of this release was performance tuning and bug
+ fixing. In addition to these, several new major changes occurred:</p>
-<li>Dan Gohman contributed support for better alignment and volatility handling
-in the code generator, and significantly enhanced alignment analysis for SSE
-load/store instructions.</li>
+<ul>
-<li>Christopher Lamb virtual register sub-register support, better truncates and
-extends on X86.</li>
+<li>Owen contributed Machine Loop info, domintors, etc. Merged dom and
+ postdom.</li>
-<li>Duraid Madina contributed a new "bigblock" register allocator, and Roman
-Levenstein contributed several big improvements. BigBlock is optimized for code
-that uses very large basic blocks. It is slightly slower than the "local"
-allocator, but produces much better code.</li>
+<li>Dan added support for emitting debug information with .file and .loc on
+targets that support it</li>
-<li>David Greene refactored the register allocator to split coalescing out from
-allocation, making coalescers pluggable.</li>
+<li>Evan physical register dependencies in the BURR scheduler</li>
+<li>Evan EXTRACT_SUBREG coalescing support</li>
</ul>
</div>
</p>
<ul>
-<li>Bruno Cardoso Lopes contributed initial MIPS support.</li>
-<li>Bill Wendling added SSSE3 support.</li>
-<li>New Target independent if converter, ARM uses it so far</li>
-<li>Nicholas Geoffray contributed improved linux/ppc ABI and JIT support.</li>
-<li>Dale Johannesen rewrote handling of 32-bit float values in the X86 backend
-when using the floating point stack, fixing several nasty bugs.</li>
-<li>Dan contributed rematerialization support for the X86 backend.</li>
+<li>Evan X86 now models EFLAGS in instructions.</li>
+<li>Evan: If conversion on by default for ARM.</li>
+<li>Bruno: MIPS PIC support.</li>
+<li>Arnold Schwaighofer: X86 tail call support.</li>
</ul>
</div>
</p>
<ul>
-<li>Duncan and Anton exception handling in llvm-gcc 4.0/4.2</li>
-
-<li>Devang and Duncan: Bitfields, pragma pack</li>
-
-<li>Tanya implemented support for __attribute__((noinline)) in llvm-gcc, and
-added support for generic variable annotations which are propagated into the
-LLVM IR, e.g. "<tt>int X __attribute__((annotate("myproperty")));</tt>".</li>
-
-<li>Sheng Zhou and Christopher Lamb implemented alias analysis support for
-'restrict' arguments to functions.</li>
-
-<li>Duncan contributed support for trampolines (pointers to nested functions),
-currently only supported on x86 target.</li>
-
+<li>.</li>
</ul>
</div>
</p>
<ul>
-<li>Neil Booth APFloat, foundation for long double support that will be wrapped
-up in 2.2. Dale contributed most of long double support, will be enabled in
-2.2.</li>
-
-<li>LLVM now provides an LLVMBuilder class which makes it significantly easier
-to create LLVM IR instructions.</li>
-
-<li>Reid contributed support for intrinsics that take arbitrary integer typed
-arguments, Dan Gohman and Chandler extended it to support FP and vectors.</li>
-</li>
-
+<li>Devang added LLVMFoldingBuilder.</li>
+<li>Dan added support for vector sin, cos, and pow intrinsics.</li>
</ul>
</div>
</p>
<ul>
-<li>BrainF frontend by Sterling Stein.</li>
-
-<li>David Green contributed a new --enable-expensive-checks configure option
-which enables STL checking, and fixed several bugs exposed by it.</li>
-
-</li>
-
+<li>.</li>
</ul>
</div>
<ul>
<li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
(and probably other unix-like systems).</li>
-<li>PowerPC and X86-based Mac OS X systems, running 10.2 and above in 32-bit and
+<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 using MinGW libraries (native).</li>
<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
support is available for native builds with Visual C++).</li>
<li>Sun UltraSPARC workstations running Solaris 8.</li>
components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
<ul>
-<li>The <tt>-cee</tt> pass is known to be buggy, and may be removed in in a
- future release.</li>
-<li>C++ EH support is disabled for this release.</li>
-<li>The MSIL backend is experimental.</li>
-<li>The IA64 code generator is experimental.</li>
-<li>The Alpha JIT is experimental.</li>
-<li>"<tt>-filetype=asm</tt>" (the default) is the only supported value for the
- <tt>-filetype</tt> llc option.</li>
+<li>The <tt>-cee</tt> pass is known to be buggy and will be removed in
+ LLVM 2.3.</li>
+<li>The MSIL, IA64, Alpha, and MIPS backends are experimental.</li>
+<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
+ value for this option.</li>
+<li>The llvmc tool is not supported.</li>
</ul>
</div>
<ul>
<li>The X86 backend does not yet support <a href="http://llvm.org/PR879">inline
assembly that uses the X86 floating point stack</a>.</li>
+<li>The X86 backend occasionally has <a href="http://llvm.org/PR1649">alignment
+ problems</a> on operating systems that don't require 16-byte stack alignment
+ (including most non-darwin OS's like linux).</li>
</ul>
</div>
<div class="doc_text">
<ul>
-<li><a href="http://llvm.org/PR642">PowerPC backend does not correctly
-implement ordered FP comparisons</a>.</li>
<li>The Linux PPC32/ABI support needs testing for the interpreter and static
compilation, and lacks support for debug information.</li>
</ul>
<ul>
<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
-processors, thumb program can crash or produces wrong
+processors, thumb programs can crash or produce wrong
results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
</li>
<ul>
<li><a href="http://llvm.org/PR802">The C backend does not support inline
assembly code</a>.</li>
+<li><a href="http://llvm.org/PR1126">The C backend does not support vectors
+ yet</a>.</li>
+<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
+ C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
+ C++ code compiled with LLC or native compilers.</li>
</ul>
</div>
<div class="doc_text">
-<p>llvm-gcc4 does not currently support <a href="http://llvm.org/PR869">Link-Time
-Optimization</a> on most platforms "out-of-the-box". Please inquire on the
+<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
+Optimization</a> on most platforms "out-of-the-box". Please inquire on the
llvmdev mailing list if you are interested.</p>
</div>
<div class="doc_text">
<ul>
-<li><p>"long double" is silently transformed by the front-end into "double". There
-is no support for floating point data types of any size other than 32 and 64
-bits.</p></li>
-
<li><p>llvm-gcc does <b>not</b> support <tt>__builtin_apply</tt> yet.
See <a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</p>
</li>
<li><p>llvm-gcc <b>partially</b> supports these GCC extensions:</p>
<ol>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html#Nested%20Functions">Nested Functions</a>: As in Algol and Pascal, lexical scoping of functions.<br>
- Nested functions are supported, but llvm-gcc does not support non-local
- gotos or taking the address of a nested function.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html#Nested%20Functions">Nested Functions</a>:
+
+ As in Algol and Pascal, lexical scoping of functions.
+ Nested functions are supported, but llvm-gcc does not support
+ taking the address of a nested function (except on the X86-32 target)
+ or non-local gotos.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Declaring that functions have no side effects or that they can never
return.<br>
- <b>Supported:</b> <tt>alias</tt>, <tt>always_inline</tt>, <tt>cdecl</tt>,
- <tt>constructor</tt>, <tt>destructor</tt>,
+ <b>Supported:</b> <tt>alias</tt>, <tt>always_inline</tt>, <tt>cdecl</tt>,
+ <tt>const</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
<tt>deprecated</tt>, <tt>fastcall</tt>, <tt>format</tt>,
- <tt>format_arg</tt>, <tt>non_null</tt>, <tt>noreturn</tt>, <tt>regparm</tt>
+ <tt>format_arg</tt>, <tt>non_null</tt>, <tt>noinline</tt>,
+ <tt>noreturn</tt>, <tt>pure</tt>, <tt>regparm</tt>
<tt>section</tt>, <tt>stdcall</tt>, <tt>unused</tt>, <tt>used</tt>,
<tt>visibility</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
- <b>Ignored:</b> <tt>noinline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
- <tt>malloc</tt>, <tt>no_instrument_function</tt></li>
+ <b>Ignored:</b> <tt>nothrow</tt>, <tt>malloc</tt>,
+ <tt>no_instrument_function</tt></li>
</ol>
</li>
itself, Qt, Mozilla, etc.</p>
<ul>
-<li>llvm-gcc4 only has partial support for <a href="http://llvm.org/PR870">C++
-Exception Handling</a>, and it is not enabled by default.</li>
-
-<!-- NO EH Support!
-
-<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
- performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
- function and in the <tt>setjmp</tt> receiver function may not be run.
- Objects in intervening stack frames will be destroyed, however (which is
- better than most compilers).</li>
-
-<li>The LLVM C++ front-end follows the <a
- href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
- This document, which is not Itanium specific, specifies a standard for name
- mangling, class layout, v-table layout, RTTI formats, and other C++
- representation issues. Because we use this API, code generated by the LLVM
- compilers should be binary compatible with machine code generated by other
- Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
- <i>However</i>, the exception handling mechanism used by llvm-gcc3 is very
- different from the model used in the Itanium ABI, so <b>exceptions will not
- interact correctly</b>. </li>
--->
+<li>Exception handling only works well on the X86 and PowerPC targets.</li>
</ul>
</div>
projects / oota-llvm.git / blobdiff