[llvm-commits] [llvm] r109013 - /llvm/trunk/docs/ReleaseNotes.html
Chris Lattner
sabre at nondot.org
Wed Jul 21 08:57:41 PDT 2010
Author: lattner
Date: Wed Jul 21 10:57:40 2010
New Revision: 109013
URL: http://llvm.org/viewvc/llvm-project?rev=109013&view=rev
Log:
strip out the 2.7 release notes, this really is the 2.8 release notes
now. Add a few items like the fpstackifier improvements.
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=109013&r1=109012&r2=109013&view=diff
==============================================================================
--- llvm/trunk/docs/ReleaseNotes.html (original)
+++ llvm/trunk/docs/ReleaseNotes.html Wed Jul 21 10:57:40 2010
@@ -118,40 +118,9 @@
integrating with other development tools. Clang is considered a
production-quality compiler for C and Objective-C on x86 (32- and 64-bit).</p>
-<p>In the LLVM 2.7 time-frame, the Clang team has made many improvements:</p>
+<p>In the LLVM 2.8 time-frame, the Clang team has made many improvements:</p>
<ul>
-
-<li>C++ Support: Clang is now capable of self-hosting! While still
-alpha-quality, Clang's C++ support has matured enough to build LLVM and Clang,
-and C++ is now enabled by default. See the <a
-href="http://clang.llvm.org/cxx_compatibility.html">Clang C++ compatibility
-page</a> for common C++ migration issues.</li>
-
-<li>Objective-C: Clang now includes experimental support for an updated
-Objective-C ABI on non-Darwin platforms. This includes support for non-fragile
-instance variables and accelerated proxies, as well as greater potential for
-future optimisations. The new ABI is used when compiling with the
--fobjc-nonfragile-abi and -fgnu-runtime options. Code compiled with these
-options may be mixed with code compiled with GCC or clang using the old GNU ABI,
-but requires the libobjc2 runtime from the GNUstep project.</li>
-
-<li>New warnings: Clang contains a number of new warnings, including
-control-flow warnings (unreachable code, missing return statements in a
-non-<code>void</code> function, etc.), sign-comparison warnings, and improved
-format-string warnings.</li>
-
-<li>CIndex API and Python bindings: Clang now includes a C API as part of the
-CIndex library. Although we may make some changes to the API in the future, it
-is intended to be stable and has been designed for use by external projects. See
-the Clang
-doxygen <a href="http://clang.llvm.org/doxygen/group__CINDEX.html">CIndex</a>
-documentation for more details. The CIndex API also includes a preliminary
-set of Python bindings.</li>
-
-<li>ARM Support: Clang now has ABI support for both the Darwin and Linux ARM
-ABIs. Coupled with many improvements to the LLVM ARM backend, Clang is now
-suitable for use as a beta quality ARM compiler.</li>
</ul>
</div>
@@ -170,10 +139,7 @@
future</a>!). The tool is very good at finding bugs that occur on specific
paths through code, such as on error conditions.</p>
-<p>In the LLVM 2.7 time-frame, the analyzer core has made several major and
- minor improvements, including better support for tracking the fields of
- structures, initial support (not enabled by default yet) for doing
- interprocedural (cross-function) analysis, and new checks have been added.
+<p>In the LLVM 2.8 time-frame,
</p>
</div>
@@ -190,26 +156,8 @@
implementation of the CLI) using LLVM for static and just-in-time
compilation.</p>
-<p>
-With the release of LLVM 2.7, VMKit has shifted to a great framework for writing
-virtual machines. VMKit now offers precise and efficient garbage collection with
-multi-threading support, thanks to the MMTk memory management toolkit, as well
-as just in time and ahead of time compilation with LLVM. The major changes in
-VMKit 0.27 are:</p>
-
-<ul>
+<p>With the release of LLVM 2.8, ...</p>
-<li>Garbage collection: VMKit now uses the MMTk toolkit for garbage collectors.
- The first collector to be ported is the MarkSweep collector, which is precise,
- and drastically improves the performance of VMKit.</li>
-<li>Line number information in the JVM: by using the debug metadata of LLVM, the
- JVM now supports precise line number information, useful when printing a stack
- trace.</li>
-<li>Interface calls in the JVM: we implemented a variant of the Interface Method
- Table technique for interface calls in the JVM.
-</li>
-
-</ul>
</div>
@@ -231,8 +179,10 @@
<p>
All of the code in the compiler-rt project is available under the standard LLVM
-License, a "BSD-style" license. New in LLVM 2.7: compiler_rt now
-supports ARM targets.</p>
+License, a "BSD-style" license. New in LLVM 2.8:
+
+Soft float support
+</p>
</div>
@@ -265,7 +215,7 @@
</p>
<p>
-DragonEgg is a new project which is seeing its first release with llvm-2.7.
+2.8 status here.
</p>
</div>
@@ -288,23 +238,13 @@
LLVM MC Project Blog Post</a>.
</p>
-<p>2.7 includes major parts of the work required by the new MC Project. A few
- targets have been refactored to support it, and work is underway to support a
- native assembler in LLVM. This work is not complete in LLVM 2.7, but it has
- made substantially more progress on LLVM mainline.</p>
-
-<p>One minor example of what MC can do is to transcode an AT&T syntax
- X86 .s file into intel syntax. You can do this with something like:</p>
-<pre>
- llvm-mc foo.s -output-asm-variant=1 -o foo-intel.s
-</pre>
-
+<p>2.8 status here</p>
</div>
<!-- *********************************************************************** -->
<div class="doc_section">
- <a name="externalproj">External Open Source Projects Using LLVM 2.7</a>
+ <a name="externalproj">External Open Source Projects Using LLVM 2.8</a>
</div>
<!-- *********************************************************************** -->
@@ -312,171 +252,13 @@
<p>An exciting aspect of LLVM is that it is used as an enabling technology for
a lot of other language and tools projects. This section lists some of the
- projects that have already been updated to work with LLVM 2.7.</p>
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="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 0.43 and later have been tested and are known to work with
-LLVM 2.7 (and continue to work with older LLVM releases >= 2.5).</p>
-
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="RoadsendPHP">Roadsend PHP</a>
-</div>
-
-<div class="doc_text">
-<p>
-<a href="http://code.roadsend.com/rphp">Roadsend PHP</a> (rphp) is an open
-source implementation of the PHP programming
-language that uses LLVM for its optimizer, JIT and static compiler. This is a
-reimplementation of an earlier project that is now based on LLVM.
-</p>
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="UnladenSwallow">Unladen Swallow</a>
-</div>
-
-<div class="doc_text">
-<p>
-<a href="http://code.google.com/p/unladen-swallow/">Unladen Swallow</a> is a
-branch of <a href="http://python.org/">Python</a> intended to be fully
-compatible and significantly faster. It uses LLVM's optimization passes and JIT
-compiler.
-</p>
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="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="safecode">SAFECode Compiler</a>
-</div>
-
-<div class="doc_text">
-<p>
-<a href="http://safecode.cs.illinois.edu">SAFECode</a> is a memory safe C
-compiler built using LLVM. It takes standard, unannotated C code, analyzes the
-code to ensure that memory accesses and array indexing operations are safe, and
-instruments the code with run-time checks when safety cannot be proven
-statically.
-</p>
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="icedtea">IcedTea Java Virtual Machine Implementation</a>
-</div>
-
-<div class="doc_text">
-<p>
-<a href="http://icedtea.classpath.org/wiki/Main_Page">IcedTea</a> provides a
-harness to build OpenJDK using only free software build tools and to provide
-replacements for the not-yet free parts of OpenJDK. One of the extensions that
-IcedTea provides is a new JIT compiler named <a
-href="http://icedtea.classpath.org/wiki/ZeroSharkFaq">Shark</a> which uses LLVM
-to provide native code generation without introducing processor-dependent
-code.
-</p>
-<p>Icedtea6 1.8 and later have been tested and are known to work with
-LLVM 2.7 (and continue to work with older LLVM releases >= 2.6 as well).
-</p>
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="llvm-lua">LLVM-Lua</a>
-</div>
-
-<div class="doc_text">
-<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>
-<p>LLVM-Lua 1.2.0 have been tested and is known to work with LLVM 2.7.
-</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 based on
-core Mac OS technologies, sponsored by Apple Inc. It uses LLVM at runtime for
-optimization passes, JIT compilation and exception handling. It also allows
-static (ahead-of-time) compilation of Ruby code straight to machine code.
-</p>
-<p>The upcoming MacRuby 0.6 release works with LLVM 2.7.
-</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 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.</p>
-
+ projects that have already been updated to work with LLVM 2.8.</p>
</div>
<!-- *********************************************************************** -->
<div class="doc_section">
- <a name="whatsnew">What's New in LLVM 2.7?</a>
+ <a name="whatsnew">What's New in LLVM 2.8?</a>
</div>
<!-- *********************************************************************** -->
@@ -496,29 +278,11 @@
<div class="doc_text">
-<p>In addition to changes to the code, between LLVM 2.6 and 2.7, a number of
+<p>In addition to changes to the code, between LLVM 2.7 and 2.8, a number of
organization changes have happened:
</p>
<ul>
-<li>LLVM has a new <a href="http://llvm.org/Logo.html">official logo</a>!</li>
-
-<li>Ted Kremenek and Doug Gregor have stepped forward as <a
- href="http://llvm.org/docs/DeveloperPolicy.html#owners">Code Owners</a> of the
- Clang static analyzer and the Clang frontend, respectively.</li>
-
-<li>LLVM now has an <a href="http://blog.llvm.org">official Blog</a> at
- <a href="http://blog.llvm.org">http://blog.llvm.org</a>. This is a great way
- to learn about new LLVM-related features as they are implemented. Several
- features in this release are already explained on the blog.</li>
-
-<li>The LLVM web pages are now checked into the SVN server, in the "www",
- "www-pubs" and "www-releases" SVN modules. Previously they were hidden in a
- largely inaccessible old CVS server.</li>
-
-<li><a href="http://llvm.org">llvm.org</a> is now hosted on a new (and much
- faster) server. It is still graciously hosted at the University of Illinois
- of Urbana Champaign.</li>
</ul>
</div>
@@ -529,43 +293,10 @@
<div class="doc_text">
-<p>LLVM 2.7 includes several major new capabilities:</p>
+<p>LLVM 2.8 includes several major new capabilities:</p>
<ul>
-<li>2.7 includes initial support for the <a
- href="http://en.wikipedia.org/wiki/MicroBlaze">MicroBlaze</a> target.
- MicroBlaze is a soft processor core designed for Xilinx FPGAs.</li>
-
-<li>2.7 includes a new LLVM IR "extensible metadata" feature. This feature
- supports many different use cases, including allowing front-end authors to
- encode source level information into LLVM IR, which is consumed by later
- language-specific passes. This is a great way to do high-level optimizations
- like devirtualization, type-based alias analysis, etc. See the <a
- href="http://blog.llvm.org/2010/04/extensible-metadata-in-llvm-ir.html">
- Extensible Metadata Blog Post</a> for more information.</li>
-
-<li>2.7 encodes <a href="SourceLevelDebugging.html">debug information</a>
-in a completely new way, built on extensible metadata. The new implementation
-is much more memory efficient and paves the way for improvements to optimized
-code debugging experience.</li>
-
-<li>2.7 now directly supports taking the address of a label and doing an
- indirect branch through a pointer. This is particularly useful for
- interpreter loops, and is used to implement the GCC "address of label"
- extension. For more information, see the <a
-href="http://blog.llvm.org/2010/01/address-of-label-and-indirect-branches.html">
-Address of Label and Indirect Branches in LLVM IR Blog Post</a>.
-
-<li>2.7 is the first release to start supporting APIs for assembling and
- disassembling target machine code. These APIs are useful for a variety of
- low level clients, and are surfaced in the new "enhanced disassembly" API.
- For more information see the <a
- href="http://blog.llvm.org/2010/01/x86-disassembler.html">The X86
- Disassembler Blog Post</a> for more information.</li>
-
-<li>2.7 includes major parts of the work required by the new MC Project,
- see the <a href="#mc">MC update above</a> for more information.</li>
-
+<li>.</li>
</ul>
</div>
@@ -580,31 +311,6 @@
expose new optimization opportunities:</p>
<ul>
-<li>LLVM IR now supports a 16-bit "half float" data type through <a
- href="LangRef.html#int_fp16">two new intrinsics</a> and APFloat support.</li>
-<li>LLVM IR supports two new <a href="LangRef.html#fnattrs">function
- attributes</a>: inlinehint and alignstack(n). The former is a hint to the
- optimizer that a function was declared 'inline' and thus the inliner should
- weight it higher when considering inlining it. The later
- indicates to the code generator that the function diverges from the platform
- ABI on stack alignment.</li>
-<li>The new <a href="LangRef.html#int_objectsize">llvm.objectsize</a> intrinsic
- allows the optimizer to infer the sizes of memory objects in some cases.
- This intrinsic is used to implement the GCC <tt>__builtin_object_size</tt>
- extension.</li>
-<li>LLVM IR now supports marking load and store instructions with <a
- href="LangRef.html#i_load">"non-temporal" hints</a> (building on the new
- metadata feature). This hint encourages the code
- generator to generate non-temporal accesses when possible, which are useful
- for code that is carefully managing cache behavior. Currently, only the
- X86 backend provides target support for this feature.</li>
-
-<li>LLVM 2.7 has pre-alpha support for <a
- href="LangRef.html#t_union">unions in LLVM IR</a>.
- Unfortunately, this support is not really usable in 2.7, so if you're
- interested in pushing it forward, please help contribute to LLVM mainline.</li>
-
-<!-- BELOW COME ACTUAL 2.8 CHANGES -->
<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>
@@ -629,48 +335,7 @@
<ul>
-<li>The inliner now merges arrays stack objects in different callees when
- inlining multiple call sites into one function. This reduces the stack size
- of the resultant function.</li>
-<li>The -basicaa alias analysis pass (which is the default) has been improved to
- be less dependent on "type safe" pointers. It can now look through bitcasts
- and other constructs more aggressively, allowing better load/store
- optimization.</li>
-<li>The load elimination optimization in the GVN Pass [<a
-href="http://blog.llvm.org/2009/12/introduction-to-load-elimination-in-gvn.html">intro
- blog post</a>] has been substantially improved to be more aggressive about
- partial redundancy elimination and do more aggressive phi translation. Please
- see the <a
- href="http://blog.llvm.org/2009/12/advanced-topics-in-redundant-load.html">
- Advanced Topics in Redundant Load Elimination with a Focus on PHI Translation
- Blog Post</a> for more details.</li>
-<li>The module <a href="LangRef.html#datalayout">target data string</a> now
- includes a notion of 'native' integer data types for the target. This
- helps mid-level optimizations avoid promoting complex sequences of
- operations to data types that are not natively supported (e.g. converting
- i32 operations to i64 on 32-bit chips).</li>
-<li>The mid-level optimizer is now conservative when operating on a module with
- no target data. Previously, it would default to SparcV9 settings, which is
- not what most people expected.</li>
-<li>Jump threading is now much more aggressive at simplifying correlated
- conditionals and threading blocks with otherwise complex logic. It has
- subsumed the old "Conditional Propagation" pass, and -condprop has been
- removed from LLVM 2.7.</li>
-<li>The -instcombine pass has been refactored from being one huge file to being
- a library of its own. Internally, it uses a customized IRBuilder to clean
- it up and simplify it.</li>
-
-<li>The optimal edge profiling pass is reliable and much more complete than in
- 2.6. It can be used with the llvm-prof tool but isn't wired up to the
- llvm-gcc and clang command line options yet.</li>
-
-<li>A new experimental alias analysis implementation, -scev-aa, has been added.
- It uses LLVM's Scalar Evolution implementation to do symbolic analysis of
- pointer offset expressions to disambiguate pointers. It can catch a few
- cases that basicaa cannot, particularly in complex loop nests.</li>
-
-<li>The default pass ordering has been tweaked for improved optimization
- effectiveness.</li>
+<li></li>
</ul>
@@ -685,19 +350,7 @@
<div class="doc_text">
<ul>
-<li>The JIT now supports generating debug information and is compatible with
-the new GDB 7.0 (and later) interfaces for registering dynamically generated
-debug info.</li>
-
-<li>The JIT now <a href="http://llvm.org/PR5184">defaults
-to compiling eagerly</a> to avoid a race condition in the lazy JIT.
-Clients that still want the lazy JIT can switch it on by calling
-<tt>ExecutionEngine::DisableLazyCompilation(false)</tt>.</li>
-
-<li>It is now possible to create more than one JIT instance in the same process.
-These JITs can generate machine code in parallel,
-although <a href="http://llvm.org/docs/ProgrammersManual.html#jitthreading">you
-still have to obey the other threading restrictions</a>.</li>
+<li></li>
</ul>
@@ -715,49 +368,7 @@
it run faster:</p>
<ul>
-<li>The 'llc -asm-verbose' option (which is now the default) has been enhanced
- to emit many useful comments to .s files indicating information about spill
- slots and loop nest structure. This should make it much easier to read and
- understand assembly files. This is wired up in llvm-gcc and clang to
- the <tt>-fverbose-asm</tt> option.</li>
-
-<li>New LSR with "full strength reduction" mode, which can reduce address
- register pressure in loops where address generation is important.</li>
-
-<li>A new codegen level Common Subexpression Elimination pass (MachineCSE)
- is available and enabled by default. It catches redundancies exposed by
- lowering.</li>
-<li>A new pre-register-allocation tail duplication pass is available and enabled
- by default, it can substantially improve branch prediction quality in some
- cases.</li>
-<li>A new sign and zero extension optimization pass (OptimizeExtsPass)
- is available and enabled by default. This pass can takes advantage
- architecture features like x86-64 implicit zero extension behavior and
- sub-registers.</li>
-<li>The code generator now supports a mode where it attempts to preserve the
- order of instructions in the input code. This is important for source that
- is hand scheduled and extremely sensitive to scheduling. It is compatible
- with the GCC <tt>-fno-schedule-insns</tt> option.</li>
-<li>The target-independent code generator now supports generating code with
- arbitrary numbers of result values. Returning more values than was
- previously supported is handled by returning through a hidden pointer. In
- 2.7, only the X86 and XCore targets have adopted support for this
- though.</li>
-<li>The code generator now supports generating code that follows the
- <a href="LangRef.html#callingconv">Glasgow Haskell Compiler Calling
- Convention</a> and ABI.</li>
-<li>The "<a href="CodeGenerator.html#selectiondag_select">DAG instruction
- selection</a>" phase of the code generator has been largely rewritten for
- 2.7. Previously, tblgen spit out tons of C++ code which was compiled and
- linked into the target to do the pattern matching, now it emits a much
- smaller table which is read by the target-independent code. The primary
- advantages of this approach is that the size and compile time of various
- targets is much improved. The X86 code generator shrunk by 1.5MB of code,
- for example.</li>
-<li>Almost the entire code generator has switched to emitting code through the
- MC interfaces instead of printing textually to the .s file. This led to a
- number of cleanups and speedups. In 2.7, debug an exception handling
- information does not go through MC yet.</li>
+<li>MachO writer works.</li>
</ul>
</div>
@@ -771,11 +382,9 @@
</p>
<ul>
-<li>The X86 backend now optimizes tails calls much more aggressively for
- functions that use the standard C calling convention.</li>
-<li>The X86 backend now models scalar SSE registers as subregs of the SSE vector
- registers, making the code generator more aggressive in cases where scalars
- and vector types are mixed.</li>
+<li>The X86 backend now supports holding X87 floating point stack values
+ in registers across basic blocks, dramatically improving performance of code
+ that uses long double, and when targetting CPUs that don't support SSE.</li>
</ul>
@@ -792,27 +401,7 @@
<ul>
-<li>The ARM backend now generates instructions in unified assembly syntax.</li>
-
-<li>llvm-gcc now has complete support for the ARM v7 NEON instruction set. This
- support differs slightly from the GCC implementation. Please see the
- <a
-href="http://blog.llvm.org/2010/04/arm-advanced-simd-neon-intrinsics-and.html">
- ARM Advanced SIMD (NEON) Intrinsics and Types in LLVM Blog Post</a> for
- helpful information if migrating code from GCC to LLVM-GCC.</li>
-
-<li>The ARM and Thumb code generators now use register scavenging for stack
- object address materialization. This allows the use of R3 as a general
- purpose register in Thumb1 code, as it was previous reserved for use in
- stack address materialization. Secondly, sequential uses of the same
- value will now re-use the materialized constant.</li>
-
-<li>The ARM backend now has good support for ARMv4 targets and has been tested
- on StrongARM hardware. Previously, LLVM only supported ARMv4T and
- newer chips.</li>
-
-<li>Atomic builtins are now supported for ARMv6 and ARMv7 (__sync_synchronize,
- __sync_fetch_and_add, etc.).</li>
+<li></li>
</ul>
@@ -831,34 +420,7 @@
</p>
<ul>
-<li>The optimizer uses the new CodeMetrics class to measure the size of code.
- Various passes (like the inliner, loop unswitcher, etc) all use this to make
- more accurate estimates of the code size impact of various
- optimizations.</li>
-<li>A new <a href="http://llvm.org/doxygen/InstructionSimplify_8h-source.html">
- llvm/Analysis/InstructionSimplify.h</a> interface is available for doing
- symbolic simplification of instructions (e.g. <tt>a+0</tt> -> <tt>a</tt>)
- without requiring the instruction to exist. This centralizes a lot of
- ad-hoc symbolic manipulation code scattered in various passes.</li>
-<li>The optimizer now uses a new <a
- href="http://llvm.org/doxygen/SSAUpdater_8h-source.html">SSAUpdater</a>
- class which efficiently supports
- doing unstructured SSA update operations. This centralized a bunch of code
- scattered throughout various passes (e.g. jump threading, lcssa,
- loop rotate, etc) for doing this sort of thing. The code generator has a
- similar <a href="http://llvm.org/doxygen/MachineSSAUpdater_8h-source.html">
- MachineSSAUpdater</a> class.</li>
-<li>The <a href="http://llvm.org/doxygen/Regex_8h-source.html">
- llvm/Support/Regex.h</a> header exposes a platform independent regular
- expression API. Building on this, the <a
- href="TestingGuide.html#FileCheck">FileCheck</a> utility now supports
- regular exressions.</li>
-<li>raw_ostream now supports a circular "debug stream" accessed with "dbgs()".
- By default, this stream works the same way as "errs()", but if you pass
- <tt>-debug-buffer-size=1000</tt> to opt, the debug stream is capped to a
- fixed sized circular buffer and the output is printed at the end of the
- program's execution. This is helpful if you have a long lived compiler
- process and you're interested in seeing snapshots in time.</li>
+<li></li>
</ul>
@@ -873,16 +435,7 @@
<p>Other miscellaneous features include:</p>
<ul>
-<li>You can now build LLVM as a big dynamic library (e.g. "libllvm2.7.so"). To
- get this, configure LLVM with the --enable-shared option.</li>
-
-<li>LLVM command line tools now overwrite their output by default. Previously,
- they would only do this with -f. This makes them more convenient to use, and
- behave more like standard unix tools.</li>
-
-<li>The opt and llc tools now autodetect whether their input is a .ll or .bc
- file, and automatically do the right thing. This means you don't need to
- explicitly use the llvm-as tool for most things.</li>
+<li></li>
</ul>
</div>
@@ -896,48 +449,18 @@
<div class="doc_text">
<p>If you're already an LLVM user or developer with out-of-tree changes based
-on LLVM 2.6, this section lists some "gotchas" that you may run into upgrading
+on LLVM 2.7, this section lists some "gotchas" that you may run into upgrading
from the previous release.</p>
<ul>
-<li>
-The Andersen's alias analysis ("anders-aa") pass, the Predicate Simplifier
-("predsimplify") pass, the LoopVR pass, the GVNPRE pass, and the random sampling
-profiling ("rsprofiling") passes have all been removed. They were not being
-actively maintained and had substantial problems. If you are interested in
-these components, you are welcome to ressurect them from SVN, fix the
-correctness problems, and resubmit them to mainline.</li>
-
-<li>LLVM now defaults to building most libraries with RTTI turned off, providing
-a code size reduction. Packagers who are interested in building LLVM to support
-plugins that require RTTI information should build with "make REQUIRE_RTTI=1"
-and should read the new <a href="Packaging.html">Advice on Packaging LLVM</a>
-document.</li>
-
-<li>The LLVM interpreter now defaults to <em>not</em> using <tt>libffi</tt> even
-if you have it installed. This makes it more likely that an LLVM built on one
-system will work when copied to a similar system. To use <tt>libffi</tt>,
-configure with <tt>--enable-libffi</tt>.</li>
-
-<li>Debug information uses a completely different representation, an LLVM 2.6
-.bc file should work with LLVM 2.7, but debug info won't come forward.</li>
-
-<li>The LLVM 2.6 (and earlier) "malloc" and "free" instructions got removed,
- along with LowerAllocations pass. Now you should just use a call to the
- malloc and free functions in libc. These calls are optimized as well as
- the old instructions were.</li>
+<li>.</li>
</ul>
<p>In addition, many APIs have changed in this release. Some of the major LLVM
API changes are:</p>
<ul>
-
-<li>The <tt>add</tt>, <tt>sub</tt>, and <tt>mul</tt> instructions no longer
-support floating-point operands. The <tt>fadd</tt>, <tt>fsub</tt>, and
-<tt>fmul</tt> instructions should be used for this purpose instead.</li>
-
</ul>
</div>
@@ -1016,8 +539,7 @@
<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
backends are experimental.</li>
<li><tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
- supported value for this option. The MachO writer is experimental, and
- works much better in mainline SVN.</li>
+ supported value for this option. XXX Update me</li>
</ul>
</div>
@@ -1034,8 +556,6 @@
all <a href="http://llvm.org/PR879">inline assembly that uses the X86
floating point stack</a>. It supports the 'f' and 't' constraints, but not
'u'.</li>
- <li>The X86 backend generates inefficient floating point code when configured
- to generate code for systems that don't have SSE2.</li>
<li>Win64 code generation wasn't widely tested. Everything should work, but we
expect small issues to happen. Also, llvm-gcc cannot build the mingw64
runtime currently due to lack of support for the 'u' inline assembly
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