<a href="http://llvm.org/releases/">releases page</a>.</p>
</div>
-
-<!-- Unfinished features in 2.5:
- Machine LICM
- Machine Sinking
- target-specific intrinsics
- gold lto plugin
- pre-alloc splitter, strong phi elim
- <tt>llc -enable-value-prop</tt>, propagation of value info
- (sign/zero ext info) from one MBB to another
- debug info for optimized code
- interpreter + libffi
+
+
+<!--
+Almost dead code.
+ include/llvm/Analysis/LiveValues.h => Dan
+ lib/Transforms/IPO/MergeFunctions.cpp => consider for 2.8.
+ llvm/Analysis/PointerTracking.h => Edwin wants this, consider for 2.8.
+-->
+
+
+<!-- Unfinished features in 2.6:
+ gcc plugin.
+ strong phi elim
+ variable debug info for optimized code
postalloc scheduler: anti dependence breaking, hazard recognizer?
-
-initial support for debug line numbers when optimization enabled, not useful in
- 2.5 but will be for 2.6.
-
+ metadata
+ loop dependence analysis
+ ELF Writer? How stable?
+ <li>PostRA scheduler improvements, ARM adoption (David Goodwin).</li>
+ 2.7 supports the GDB 7.0 jit interfaces for debug info.
-->
<!-- 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.
+
-->
<!-- *********************************************************************** -->
<div class="doc_text">
<p>
The LLVM 2.6 distribution currently consists of code from the core LLVM
-repository —which roughly includes the LLVM optimizers, code generators
-and supporting tools — and the llvm-gcc repository. In addition to this
-code, the LLVM Project includes other sub-projects that are in development. The
-two which are the most actively developed are the <a href="#clang">Clang
-Project</a> and the <a href="#vmkit">VMKit Project</a>.
+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
+development. Here we include updates on these subprojects.
</p>
</div>
<div class="doc_text">
<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. While Clang is not included in the LLVM 2.6 release, it is
-continuing to make major strides forward in all areas. Its C and Objective-C
-parsing and code generation support is now very solid. For example, it is
-capable of successfully building many real-world applications for X86-32
-and X86-64,
-including the <a href="http://wiki.freebsd.org/BuildingFreeBSDWithClang">FreeBSD
-kernel</a> and <a href="http://gcc.gnu.org/gcc-4.2/">gcc 4.2</a>. C++ is also
-making <a href="http://clang.llvm.org/cxx_status.html">incredible progress</a>,
-and work on templates has recently started. If you are
-interested in fast compiles and good diagnostics, we encourage you to try it out
-by <a href="http://clang.llvm.org/get_started.html">building from mainline</a>
-and reporting any issues you hit to the <a
+a set of new 'LLVM native' front-end technologies for the C family of languages.
+LLVM 2.6 is the first release to officially include Clang, and it provides a
+production quality C and Objective-C compiler. If you are interested in <a
+href="http://clang.llvm.org/performance.html">fast compiles</a> and
+<a href="http://clang.llvm.org/diagnostics.html">good diagnostics</a>, we
+encourage you to try it out. Clang currently compiles typical Objective-C code
+3x faster than GCC and compiles C code about 30% faster than GCC at -O0 -g
+(which is when the most pressure is on the frontend).</p>
+
+<p>In addition to supporting these languages, C++ support is also <a
+href="http://clang.llvm.org/cxx_status.html">well under way</a>, and mainline
+Clang is able to parse the libstdc++ 4.2 headers and even codegen simple apps.
+If you are interested in Clang C++ support or any other Clang feature, we
+strongly encourage you to get involved on the <a
href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev">Clang front-end mailing
list</a>.</p>
<p>In the LLVM 2.6 time-frame, the Clang team has made many improvements:</p>
<ul>
-<li>Something wonderful!</li>
+<li>C and Objective-C support are now considered production quality.</li>
+<li>AuroraUX, FreeBSD, and OpenBSD are now supported.</li>
+<li>Most of Objective-C 2.0 is now supported with the GNU runtime.</li>
<li>Many many bugs are fixed and many features have been added.</li>
</ul>
</div>
<div class="doc_text">
-<p>Previously announced in the 2.4 LLVM release, the Clang project also
+<p><b>UPDATE!</b> Previously announced in the 2.4 and 2.5 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 a growing set of checks to find
-bugs that occur on a specific path within a program.</p>
-
-<p>In the LLVM 2.6 time-frame there have been many significant improvements to
-XYZ.</p>
-
-<p>The set of checks performed by the static analyzer continues to expand, and
+in C and Objective-C programs. The tool performs checks to find
+bugs that occur on a specific path within a program.
+The set of checks performed by the static analyzer continues to expand, and
future plans for the tool include full source-level inter-procedural analysis
and deeper checks such as buffer overrun detection. There are many opportunities
to extend and enhance the static analyzer, and anyone interested in working on
<div class="doc_text">
<p>
The <a href="http://vmkit.llvm.org/">VMKit project</a> is an implementation of
-a JVM and a CLI Virtual Machines (Microsoft .NET is an
-implementation of the CLI) using the Just-In-Time compiler of LLVM.</p>
+a JVM and a CLI Virtual Machine (Microsoft .NET is an
+implementation of the CLI) using LLVM for static and just-in-time
+compilation.</p>
-<p>Following LLVM 2.6, VMKit has its XYZ release that you can find on its
-<a href="http://vmkit.llvm.org/releases/">webpage</a>. The release includes
+<p>
+VMKit version 0.26 builds with LLVM 2.6 and you can find it on its
+<a href="http://vmkit.llvm.org/releases/">web page</a>. The release includes
bug fixes, cleanup and new features. The major changes are:</p>
<ul>
-<li>Something wonderful!</li>
+<li>A new llcj tool to generate shared libraries or executables of Java
+ files.</li>
+<li>Cooperative garbage collection. </li>
+<li>Fast subtype checking (paper from Click et al [JGI'02]). </li>
+<li>Implementation of a two-word header for Java objects instead of the original
+ three-word header. </li>
+<li>Better Java specification-compliance: division by zero checks, stack
+ overflow checks, finalization and references support. </li>
</ul>
</div>
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="compiler-rt">compiler-rt: Compiler Runtime Library</a>
+</div>
+
+<div class="doc_text">
+<p>
+The new LLVM <a href="http://compiler-rt.llvm.org/">compiler-rt project</a>
+is a simple library that provides an implementation of the low-level
+target-specific hooks required by code generation and other runtime components.
+For example, when compiling for a 32-bit target, converting a double to a 64-bit
+unsigned integer is compiled into a runtime call to the "__fixunsdfdi"
+function. The compiler-rt library provides highly optimized implementations of
+this and other low-level routines (some are 3x faster than the equivalent
+libgcc routines).</p>
+
+<p>
+All of the code in the compiler-rt project is available under the standard LLVM
+License, a "BSD-style" license.</p>
+
+</div>
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="klee">KLEE: Symbolic Execution and Automatic Test Case Generator</a>
+</div>
+
+<div class="doc_text">
+<p>
+The new LLVM <a href="http://klee.llvm.org/">KLEE project</a> is a symbolic
+execution framework for programs in LLVM bitcode form. KLEE tries to
+symbolically evaluate "all" paths through the application and records state
+transitions that lead to fault states. This allows it to construct testcases
+that lead to faults and can even be used to verify algorithms. For more
+details, please see the <a
+href="http://llvm.org/pubs/2008-12-OSDI-KLEE.html">OSDI 2008 paper</a> about
+KLEE.</p>
+
+</div>
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="dragonegg">Dragon Egg: An LLVM backend plugin for GCC</a>
+</div>
+
+<div class="doc_text">
+<p>
+<b>Duncan needs to write me</b>.
+</p>
+
+</div>
+
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="mc">llvm-mc: Machine Code Toolkit</a>
+</div>
+
+<div class="doc_text">
+<p>
+The LLVM Machine Code (MC) Toolkit project is a (very early) effort to build
+better tools for dealing with machine code, object file formats, etc. The idea
+is to be able to generate most of the target specific details of assemblers and
+disassemblers from existing LLVM target .td files (with suitable enhancements),
+and to build infrastructure for reading and writing common object file formats.
+One of the first deliverables is to build a full assembler and integrate it into
+the compiler, which is predicted to substantially reduce compile time in some
+scenarios.
+</p>
+
+<p>In the LLVM 2.6 timeframe, the MC framework has grown to the point where it
+can reliably parse and pretty print (with some encoding information) a
+darwin/x86 .s file successfully, and has the very early phases of a Mach-O
+assembler in progress. Beyond the MC framework itself, major refactoring of the
+LLVM code generator has started. The idea is to make the code generator reason
+about the code it is producing in a much more semantic way, rather than a
+textual way. For example, the code generator now uses MCSection objects to
+represent section assignments, instead of text strings that print to .section
+directives.</p>
+
+<p>MC is an early and ongoing project that will hopefully continue to lead to
+many improvements in the code generator and build infrastructure useful for many
+other situations.
+</p>
+
+</div>
+
+
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="externalproj">External Projects Using LLVM 2.6</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 2.6.</p>
+</div>
+
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="Rubinius">Rubinius</a>
+</div>
+
+<div class="doc_text">
+<p><a href="http://github.com/evanphx/rubinius">Rubinius</a> is an environment
+for running Ruby code which strives to write as much of the core class
+implementation in Ruby as possible. Combined with a bytecode interpreting VM, it
+uses LLVM to optimize and compile ruby code down to machine code. Techniques
+such as type feedback, method inlining, and uncommon traps are all used to
+remove dynamism from ruby execution and increase performance.</p>
+
+<p>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>
+</div>
+
+<div class="doc_text">
+
+<p>
+<a href="http://macruby.org">MacRuby</a> is an implementation of Ruby on top of
+core Mac OS X technologies, such as the Objective-C common runtime and garbage
+collector, and the CoreFoundation framework. It is principally developed by
+Apple and aims at enabling the creation of full-fledged Mac OS X applications.
+</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>
+
+</div>
+
+
<!--=========================================================================-->
<div class="doc_subsection">
<a name="pure">Pure</a>
an easy-to-use C interface. The interpreter uses LLVM as a backend to
JIT-compile Pure programs to fast native code.</p>
-<p>In addition to the usual algebraic data structures, Pure also has
-MATLAB-style matrices in order to support numeric computations and signal
-processing in an efficient way. Pure is mainly aimed at mathematical
-applications right now, but it has been designed as a general purpose language.
-The dynamic interpreter environment and the C interface make it possible to use
-it as a kind of functional scripting language for many application areas.
+<p>Pure versions 0.31 and later have been tested and are known to work with
+LLVM 2.6 (and continue to work with older LLVM releases >= 2.3 as well).
</p>
</div>
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 bugfixes, and better x86-64 support. This has allowed
+support, general bug fixes, and better x86-64 support. This has allowed
some major improvements in LDC, getting us much closer to being as
fully featured as the original DMD compiler from DigitalMars.
</p>
</div>
<div class="doc_text">
-<p><a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
+<p>
+<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
source implementation of the PHP programming
language that uses LLVM for its optimizer, JIT, and static compiler. This is a
reimplementation of an earlier project that is now based on LLVM.</p>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="Unladen Swallow">Unladen Swallow</a>
+<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
+<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 class="doc_subsection">
-<a name="Rubinius">Rubinius</a>
+<a name="llvm-lua">llvm-lua</a>
</div>
<div class="doc_text">
-<p><a href="http://github.com/evanphx/rubinius">Rubinius</a> is a new virtual
-machine for Ruby. It leverages LLVM to dynamically compile Ruby code down to
-machine code using LLVM's JIT.</p>
+<p>
+<a href="http://code.google.com/p/llvm-lua/">LLVM-Lua</a> uses LLVM to add JIT
+and static compiling support to the Lua VM. Lua bytecode is analyzed to
+remove type checks, then LLVM is used to compile the bytecode down to machine
+code.</p>
</div>
+
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="whatsnew">What's New in LLVM 2.6?</a>
minor improvements. Some of the major improvements and new features are listed
in this section.
</p>
+
</div>
<!--=========================================================================-->
<p>LLVM 2.6 includes several major new capabilities:</p>
<ul>
-<li>Something wonderful!</li>
+<li>New <a href="#compiler-rt">compiler-rt</a>, <A href="#klee">KLEE</a>,
+ and <a href="#mc">machine code toolkit</a> sub-projects.</li>
+<li>Debug information now includes line numbers when optimizations are enabled.
+ This allows statistical sampling tools like oprofile and Shark to map
+ samples back to source lines.</li>
+<li>LLVM now includes new experimental backends to support the MSP430, SystemZ,
+ and BlackFin architectures.</li>
+<li>LLVM supports a new <a href="GoldPlugin.html">Gold Linker Plugin</a> which
+ enables support for <a href="LinkTimeOptimization.html">transparent
+ link-time optimization</a> on ELF targets when used with the Gold binutils
+ linker.</li>
+<li>LLVM now supports doing optimization and code generation on multiple
+ threads. Please see the <a href="ProgrammersManual.html#threading">LLVM
+ Programmer's Manual</a> for more information.</li>
+<li>LLVM now has experimental support for <a
+ href="http://nondot.org/~sabre/LLVMNotes/EmbeddedMetadata.txt">embedded
+ metadata</a> in LLVM IR, though the implementation is not guaranteed to be
+ final and the .bc file format may change in future releases. Debug info
+ does not yet use this format in LLVM 2.6.</li>
</ul>
</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="llvm-gcc">llvm-gcc 4.2 Improvements</a>
-</div>
-
-<div class="doc_text">
-
-<p>LLVM fully supports the llvm-gcc 4.2 front-end, which marries the GCC
-front-ends and driver with the LLVM optimizer and code generator. It currently
-includes support for the C, C++, Objective-C, Ada, and Fortran front-ends.</p>
-
-<ul>
-<li>Something wonderful!</li>
-</ul>
-
-</div>
-
-
<!--=========================================================================-->
<div class="doc_subsection">
<a name="coreimprovements">LLVM IR and Core Improvements</a>
</div>
<div class="doc_text">
-<p>LLVM IR has several new features that are used by our existing front-ends and
-can be useful if you are writing a front-end for LLVM:</p>
+<p>LLVM IR has several new features for better support of new targets and that
+expose new optimization opportunities:</p>
<ul>
-<li>Something wonderful!</li>
+<li>The <a href="LangRef.html#i_add">add</a>, <a
+ href="LangRef.html#i_sub">sub</a>, and <a href="LangRef.html#i_mul">mul</a>
+ instructions have been split into integer and floating point versions (like
+ divide and remainder), introducing new <a
+ href="LangRef.html#i_fadd">fadd</a>, <a href="LangRef.html#i_fsub">fsub</a>,
+ and <a href="LangRef.html#i_fmul">fmul</a> instructions.</li>
+<li>The <a href="LangRef.html#i_add">add</a>, <a
+ href="LangRef.html#i_sub">sub</a>, and <a href="LangRef.html#i_mul">mul</a>
+ instructions now support optional "nsw" and "nuw" bits which indicate that
+ the operation is guaranteed to not overflow (in the signed or
+ unsigned case, respectively). This gives the optimizer more information and
+ can be used for things like C signed integer values, which are undefined on
+ overflow.</li>
+<li>The <a href="LangRef.html#i_sdiv">sdiv</a> instruction now supports an
+ optional "exact" flag which indicates that the result of the division is
+ guaranteed to have a remainder of zero. This is useful for optimizing pointer
+ subtraction in C.</li>
+<li>The <a href="LangRef.html#i_getelementptr">getelementptr</a> instruction now
+ supports arbitrary integer index values for array/pointer indices. This
+ allows for better code generation on 16-bit targets like PIC16.</li>
+<li>The <a href="LangRef.html#i_getelementptr">getelementptr</a> instruction now
+ supports an "inbounds" optimization hint that tells the optimizer that the
+ pointer is guaranteed to be within its allocated object.</li>
+<li>LLVM now support a series of new linkage types for global values which allow
+ for better optimization and new capabilities:
+ <ul>
+ <li><a href="LangRef.html#linkage_linkonce">linkonce_odr</a> and
+ <a href="LangRef.html#linkage_weak">weak_odr</a> have the same linkage
+ semantics as the non-"odr" linkage types. The difference is that these
+ linkage types indicate that all definitions of the specified function
+ are guaranteed to have the same semantics. This allows inlining
+ templates functions in C++ but not inlining weak functions in C,
+ which previously both got the same linkage type.</li>
+ <li><a href="LangRef.html#linkage_available_externally">available_externally
+ </a> is a new linkage type that gives the optimizer visibility into the
+ definition of a function (allowing inlining and side effect analysis)
+ but that does not cause code to be generated. This allows better
+ optimization of "GNU inline" functions, extern templates, etc.</li>
+ <li><a href="LangRef.html#linkage_linker_private">linker_private</a> is a
+ new linkage type (which is only useful on Mac OS X) that is used for
+ some metadata generation and other obscure things.</li>
+ </ul></li>
+<li>Finally, target-specific intrinsics can now return multiple values, which
+ is useful for modeling target operations with multiple results.</li>
</ul>
</div>
<div class="doc_text">
-<p>In addition to a large array of bug fixes and minor performance tweaks, this
+<p>In addition to a large array of minor performance tweaks and bug fixes, this
release includes a few major enhancements and additions to the optimizers:</p>
<ul>
-<li>Something wonderful!</li>
+<li>The <a href="Passes.html#scalarrepl">Scalar Replacement of Aggregates</a>
+ pass has many improvements that allow it to better promote vector unions,
+ variables which are memset, and much more strange code that can happen to
+ do bitfield accesses to register operations. An interesting change is that
+ it now produces "unusual" integer sizes (like i1704) in some cases and lets
+ other optimizers clean things up.</li>
+<li>The <a href="Passes.html#loop-reduce">Loop Strength Reduction</a> pass now
+ promotes small integer induction variables to 64-bit on 64-bit targets,
+ which provides a major performance boost for much numerical code. It also
+ promotes shorts to int on 32-bit hosts, etc. LSR now also analyzes pointer
+ expressions (e.g. getelementptrs), as well as integers.</li>
+<li>The <a href="Passes.html#gvn">GVN</a> pass now eliminates partial
+ redundancies of loads in simple cases.</li>
+<li>The <a href="Passes.html#inline">Inliner</a> now reuses stack space when
+ inlining similar arrays from multiple callees into one caller.</li>
+<li>LLVM includes a new experimental Static Single Information (SSI)
+ construction pass.</li>
+</li>
</ul>
<ul>
-<li>Something wonderful!</li>
+<li>The <tt>llc -asm-verbose</tt> option (exposed from llvm-gcc and clang as
+ <tt>-fverbose-asm</tt>) now adds a lot of useful information in comments to
+ the generated .s file. This information includes location information (if
+ built with <tt>-g</tt>) and loop nest information.</li>
+<li>The code generator now supports a new MachineVerifier pass which is useful
+ for finding bugs in targets and codegen passes.</li>
+<li>The Machine LICM is now enabled by default. It hoists instructions out of
+ loops (such as constant pool loads, loads from read-only stubs, vector
+ constant synthesization code, etc) and is currently configured to only do so
+ when the hoisted operation can be rematerialized.</li>
+<li>The Machine Sinking pass is now enabled by default. This pass moves
+ side-effect free operations down the CFG so that they are executed on fewer
+ paths through a function.</li>
+<li>The code generator now performs "Stack slot coloring" of register spills,
+ which allows spill slots to be reused. This leads to smaller stack frames
+ in cases where there are lots of register spills.</li>
+<li>The register allocator has many improvements to take better advantage of
+ commutable operations, various spiller peephole optimizations, and can now
+ coalesce cross-register-class copies.</li>
+<li>Tblgen now supports multiclass inheritance and a number of new string and
+ list operations like !(subst), !(foreach), !car, !cdr, !null, !if, !cast.
+ These make the .td files more expressive and allow more aggressive factoring
+ of duplication across instruction patterns.</li>
+<li>Target-specific intrinsics can now be added without having to hack VMCore to
+ add them. This makes it easier to maintain out-of-tree targets.</li>
+<li>The instruction selector is better at propagating information about values
+ (such as whether they are sign/zero extended etc) across basic block
+ boundaries.</li>
+<li>SelectionDAGS: New BuildVectorSDNode (r65296), and ISD::VECTOR_SHUFFLE (r69952 / PR2957)</li>
+<li>The Prolog/Epilog Insertion Pass now has experimental support for performing
+ the "shrink wrapping" optimization, which moves spills and reloads around in
+ the CFG to avoid doing saves on paths that don't need them.</li>
+<li>LLVM includes new experimental support for writing ELF .o files directly
+ from the compiler. It works well for many simple C testcases, but doesn't
+ support exception handling, debug info, inline assembly, etc.</li>
+<li>Targets can now specify register allocation hints through
+ MachineRegisterInfo:: setRegAllocationHint. A regalloc hint consists of hint
+ type and physical register number. A hint type of zero specifies a register
+ allocation preference. Other hint type values are target specific which are
+ resolved by TargetRegisterInfo::ResolveRegAllocHint. An example is the ARM
+ target which uses register hints to request that the register allocator
+ provide an even / odd register pair to two virtual registers.</li>
</ul>
</div>
<ul>
-<li>Something wonderful!</li>
+<li>Preliminary support for addrspace 256 -> GS, 257 -> FS, known problems: CodeGenerator.html#x86_memory</li>
+<li>Support for softfloat modes, typically used by OS kernels.</li>
+
+<li>X86-64: better modeling of implicit zero extensions, eliminates a lot of redundant zexts</li>
+<li>X86-64 TLS support for local exec and initial exec.</li>
+<li>Better modeling of H registers as subregs.</li>
+<li>Vector icmp/fcmp now work with SSE codegen.</li>
+<li>SSE 4.2 support.</li>
+<li>all global variable reference logic is now in ClassifyGlobalReference.</li>
+</li>
</ul>
</div>
</p>
<ul>
-<li>Something wonderful!</li>
+<li>Support for floating-point, indirect function calls, and
+ passing/returning aggregate types to functions.
+<li>The code generator is able to generate debug info into output COFF files.
+<li>Support for placing an object into a specific section or at a specific
+ address in memory.</li>
</ul>
<p>Things not yet supported:</p>
<ul>
-<li>Floating point.</li>
-<li>Passing/returning aggregate types to and from functions.</li>
<li>Variable arguments.</li>
-<li>Indirect function calls.</li>
<li>Interrupts/programs.</li>
-<li>Debug info.</li>
</ul>
</div>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="ARM">ARM Target Improvements</a>
+</div>
+
+<div class="doc_text">
+<p>New features of the ARM target include:
+</p>
+
+<ul>
+
+<li>Preliminary support for processors, such as the Cortex-A8 and Cortex-A9,
+that implement version v7-A of the ARM architecture. The ARM backend now
+supports both the Thumb2 and Advanced SIMD (Neon) instruction sets. The
+AAPCS-VFP "hard float" calling conventions are also supported with the
+<tt>-float-abi=hard</tt> flag. These features are still somewhat experimental
+and subject to change. The Neon intrinsics, in particular, may change in future
+releases of LLVM.
+</li>
+
+ ARM AAPCS-VFP hard float ABI is supported.
+ ARM calling convention code is now tblgen generated instead of manual.
+ ARM: NEON support. neonfp for doing single precision fp with neon instead of VFP.
+
+</ul>
+
+</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="llvmc">Improvements in LLVMC</a>
+<a name="OtherTarget">Other Target Specific Improvements</a>
+</div>
+
+<div class="doc_text">
+<p>New features of other targets include:
+</p>
+
+<ul>
+<li>Mips now supports O32 Calling Convention.</li>
+<li>Many improvements to the 32-bit PowerPC SVR4 ABI (used on powerpc-linux)
+ support, lots of bugs fixed.</li>
+<li>Added support for the 64-bit PowerPC SVR4 ABI (used on powerpc64-linux).
+ Needs more testing.</li>
+</ul>
+
+</div>
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="executionengine">Interpreter and JIT Improvements</a>
</div>
<div class="doc_text">
-<p>New features include:</p>
<ul>
-<li>Something wonderful!</li>
+<li>The JIT now supports generating more than 16M of code.</li>
+<li>When configured with --with-oprofile, the JIT can now inform oprofile about
+ JIT'd code, allowing oprofile to get line number and function name
+ information for JIT'd functions.</li>
+<li>When "libffi" is available, the LLVM interpreter now uses it, which supports
+ calling almost arbitrary external (natively compiled) functions.</li>
+<li>Clients of the JIT can now register a 'JITEventListener' object to receive
+ callbacks when the JIT emits or frees machine code. The OProfile support
+ uses this mechanism.</li>
+</ul>
+
+</div>
+
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="newapis">New Useful APIs</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+<li>New EngineBuilder class for creating JITs: r76276</li>
+ New PrettyStackTrace, crashes of llvm tools should give some indication of what the compiler was doing at the time of the crash (e.g. running a pass), and print out command line arguments.
+ StringRef class, Twine class.
+ New WeakVH and AssertingVH and CallbackVH classes.
+ New llvm/ADT/Triple class.
+ llvm_report_error() error handling API (llvm/Support/ErrorHandling.h)
+ New llvm/System/Atomic.h, llvm/System/RWMutex.h for portable atomic ops, rw locks.
+ New SourceMgr, SMLoc classes for simple parsers with caret diagnostics and #include support, (used by
+ tablegen, llvm-mc, the .ll parser, FileCheck, etc)
+
+</ul>
+
+
+</div>
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="otherimprovements">Other Improvements and New Features</a>
+</div>
+
+<div class="doc_text">
+<p>Other miscellaneous features include:</p>
+
+<ul>
+<li>LLVM now includes a new internal '<a
+ href="http://llvm.org/cmds/FileCheck.html">FileCheck</a>' tool which allows
+ writing much more accurate regression tests that run faster. Please see the
+ <a href="TestingGuide.html#FileCheck">FileCheck section of the Testing
+ Guide</a> for more information.</li>
+<li>LLVM profile information support has been significantly improved to produce
+correct use counts, and has support for edge profiling with reduced runtime
+overhead. Combined, the generated profile information is both more correct and
+imposes about half as much overhead (2.6. from 12% to 6% overhead on SPEC
+CPU2000).</li>
+<li>Many extensions to the C APIs.</li>
+<li>LLVM 2.6 includes a brand new experimental LLVM bindings to the Ada2005
+programming language.</li>
+
+<li>LLVMC:
+
+* Dynamic plugins now work on Windows.
+* New option property: init. Makes possible to provide default values for
+ options defined in plugins (interface to cl::init).
+* New example: Skeleton, shows how to create a standalone LLVMC-based driver.
+* New example: mcc16, a driver for the PIC16 toolchain.</li>
+
</ul>
</div>
<ul>
-<li>Something horrible!</li>
-
+<li>The Itanium (IA64) backend has been removed. It was not supported and
+ had bitrotted.</li>
+<li>The BigBlock register allocator has been removed, it had also bitrotted.</li>
+<li>The C Backend (-march=c) is no longer considered part of the LLVM release
+criteria. We still want it to work, but no one is maintaining it and it lacks
+support for arbitrary precision integers and other important IR features.</li>
</ul>
+ LLVM build now builds all libraries as .a files instead of some
+ libraries as relinked .o files. This requires some APIs like
+ InitializeAllTargets.h. TargetRegistry!
+
+
+
<p>In addition, many APIs have changed in this release. Some of the major LLVM
API changes are:</p>
+
+ API Cleanup:
+ no use of hash_set/hash_map, no more llvm::OStream
+ Use raw_ostream for everything, killed off llvm/Streams.h and DOUT
+
<ul>
<li>LLVM's global uniquing tables for <tt>Type</tt>s and <tt>Constant</tt>s have
been privatized into members of an <tt>LLVMContext</tt>. A number of APIs
<li><tt>SCEVHandle</tt> no longer exists, because reference counting is no
longer done for <tt>SCEV*</tt> objects, instead <tt>const SCEV*</tt> should be
used.</li>
-<li>llvm-dis now fails if output file exists, instead of dumping to stdout.
-FIXME: describe any other tool changes due to the raw_fd_ostream change</li>
-<li>temporarely due to Context API change passes should call doInitialization()
+
+<li>Many APIs, notably <tt>llvm::Value</tt>, now use the <tt>StringRef</tt>
+and <tt>Twine</tt> classes instead of passing <tt>const char*</tt>
+or <tt>std::string</tt>, as described in
+the <a href="ProgrammersManual.html#string_apis">Programmer's Manual</a>. Most
+clients should be unaffected by this transition, unless they are used to <tt>Value::getName()</tt> returning a string. Here are some tips on updating to 2.6:
+ <ul>
+ <li><tt>getNameStr()</tt> is still available, and matches the old
+ behavior. Replacing <tt>getName()</tt> calls with this is an safe option,
+ although more efficient alternatives are now possible.</li>
+
+ <li>If you were just relying on <tt>getName()</tt> being able to be sent to
+ a <tt>std::ostream</tt>, consider migrating
+ to <tt>llvm::raw_ostream</tt>.</li>
+
+ <li>If you were using <tt>getName().c_str()</tt> to get a <tt>const
+ char*</tt> pointer to the name, you can use <tt>getName().data()</tt>.
+ Note that this string (as before), may not be the entire name if the
+ name contains embedded null characters.</li>
+
+ <li>If you were using operator plus on the result of <tt>getName()</tt> and
+ treating the result as an <tt>std::string</tt>, you can either
+ use <tt>Twine::str</tt> to get the result as an <tt>std::string</tt>, or
+ could move to a <tt>Twine</tt> based design.</li>
+
+ <li><tt>isName()</tt> should be replaced with comparison
+ against <tt>getName()</tt> (this is now efficient).
+ </ul>
+</li>
+
+<li>The registration interfaces for backend Targets has changed (what was
+previously TargetMachineRegistry). For backend authors, see the <a href="WritingAnLLVMBackend.html#TargetRegistration">Writing An LLVM Backend</a> guide. For clients, the notable API changes are:
+ <ul>
+ <li><tt>TargetMachineRegistry</tt> has been renamed
+ to <tt>TargetRegistry</tt>.</li>
+
+ <li>Clients should move to using the <tt>TargetRegistry::lookupTarget()</tt>
+ function to find targets.</li>
+ </ul>
+</li>
+
+<li>llvm-dis now fails if the output file exists, instead of dumping to stdout.
+FIXME: describe any other tool changes due to the raw_fd_ostream change. FIXME:
+This is not an API change, maybe there should be a tool changes section?</li>
+<li>temporarily due to Context API change passes should call doInitialization()
method of the pass they inherit from, otherwise Context is NULL.
FIXME: remove this entry when this is no longer needed.<li>
</ul>
support is available for native builds with Visual C++).</li>
<li>Sun UltraSPARC workstations running Solaris 10.</li>
<li>Alpha-based machines running Debian GNU/Linux.</li>
-<li>Itanium-based (IA64) machines running Linux and HP-UX.</li>
</ul>
<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
See: <a href="#brokengcc">Broken versions of GCC and other tools</a>.
However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
for x86/x64 has been made available from the third party AuroraUX Project
-that has been meticulously tested for bootstrapping LLVM & Clang.</li>
+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, IA64, Alpha, SPU, MIPS, and PIC16 backends are experimental.</li>
+<li>The MSIL, Alpha, SPU, MIPS, and PIC16 backends are experimental.</li>
<li>The <tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
supported value for this option.</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>
<li>Compilation for ARM Linux OABI (old ABI) is supported but not fully tested.
</li>
-<li>There is a bug in QEMU-ARM (<= 0.9.0) which causes it to incorrectly
- execute
-programs compiled with LLVM. Please use more recent versions of QEMU.</li>
</ul>
</div>
</ul>
</div>
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="ia64-be">Known problems with the IA64 back-end</a>
-</div>
-
-<div class="doc_text">
-
-<ul>
-<li>The Itanium backend is highly experimental and has a number of known
- issues. We are looking for a maintainer for the Itanium backend. If you
- are interested, please contact the LLVMdev mailing list.</li>
-</ul>
-
-</div>
-
<!-- ======================================================================= -->
<div class="doc_subsection">
<a name="c-be">Known problems with the C back-end</a>
</ul>
</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="ocaml-bindingse">Known problems with the O'Caml bindings</a>
+</div>
+
+<div class="doc_text">
+
+<p>The Llvm.Linkage module is broken, and has incorrect values. Only
+Llvm.Linkage.External, Llvm.Linkage.Available_externally, and
+Llvm.Linkage.Link_once will be correct. If you need any of the other linkage
+modes, you'll have to write an external C library in order to expose the
+functionality. This has been fixed in the trunk.</p>
+</div>
+
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="additionalinfo">Additional Information</a>
projects / oota-llvm.git / blobdiff