<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link rel="stylesheet" href="llvm.css" type="text/css">
- <title>LLVM 2.7 Release Notes</title>
+ <title>LLVM 2.8 Release Notes</title>
</head>
<body>
-<div class="doc_title">LLVM 2.7 Release Notes</div>
+<div class="doc_title">LLVM 2.8 Release Notes</div>
<img align=right src="http://llvm.org/img/DragonSmall.png"
- width="136" height="136">
+ width="136" height="136" alt="LLVM Dragon Logo">
<ol>
<li><a href="#intro">Introduction</a></li>
<li><a href="#subproj">Sub-project Status Update</a></li>
- <li><a href="#externalproj">External Projects Using LLVM 2.7</a></li>
- <li><a href="#whatsnew">What's New in LLVM 2.7?</a></li>
+ <li><a href="#externalproj">External Projects Using LLVM 2.8</a></li>
+ <li><a href="#whatsnew">What's New in LLVM 2.8?</a></li>
<li><a href="GettingStarted.html">Installation Instructions</a></li>
<li><a href="#portability">Portability and Supported Platforms</a></li>
<li><a href="#knownproblems">Known Problems</a></li>
<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
release.<br>
You may prefer the
-<a href="http://llvm.org/releases/2.6/docs/ReleaseNotes.html">LLVM 2.7
-Release Notes</a>.</h1>-->
+<a href="http://llvm.org/releases/2.7/docs/ReleaseNotes.html">LLVM 2.7
+Release Notes</a>.</h1>
<!-- *********************************************************************** -->
<div class="doc_section">
<div class="doc_text">
<p>This document contains the release notes for the LLVM Compiler
-Infrastructure, release 2.7. Here we describe the status of LLVM, including
+Infrastructure, release 2.8. Here we describe the status of LLVM, including
major improvements from the previous release and significant known problems.
All LLVM releases may be downloaded from the <a
href="http://llvm.org/releases/">LLVM releases web site</a>.</p>
-->
-<!-- Features that need text if they're finished for 2.7:
+<!-- Features that need text if they're finished for 2.8:
+ combiner-aa?
strong phi elim
llvm.dbg.value: variable debug info for optimized code
loop dependence analysis
<!-- 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 2.7 distribution currently consists of code from the core LLVM
+The LLVM 2.8 distribution currently consists of code from the core LLVM
repository (which roughly includes the LLVM optimizers, code generators
and supporting tools), the Clang repository and the llvm-gcc repository. In
addition to this code, the LLVM Project includes other sub-projects that are in
<div class="doc_text">
-<p>The <a href="http://clang.llvm.org/">Clang project</a> is ...</p>
+<p><a href="http://clang.llvm.org/">Clang</a> is an LLVM front end for the C,
+C++, and Objective-C languages. Clang aims to provide a better user experience
+through expressive diagnostics, a high level of conformance to language
+standards, fast compilation, and low memory use. Like LLVM, Clang provides a
+modular, library-based architecture that makes it suitable for creating or
+integrating with other development tools. Clang is considered a
+production-quality compiler for C 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>FIXME: C++! Include a link to cxx_compatibility.html</li>
-
-<li>FIXME: Static Analyzer improvements?</li>
-
-<li>CIndex API and Python bindings: Clang now includes a C API as part of the
-CIndex library. Although we make make some changes to the API in the future, it
-is intended to be stable and has been designed for use by external projects. See
-the Clang
-doxygen <a href="http://clang.llvm.org/doxygen/group__CINDEX.html">CIndex</a>
-documentation for more details. The CIndex API also includings an preliminary
-set of Python bindings.</li>
-<li>ARM Support: Clang now has ABI support for both the Darwin and Linux ARM
-ABIs. Coupled with many improvements to the LLVM ARM backend, Clang is now
-suitable for use as a a beta quality ARM compiler.</li>
</ul>
</div>
<div class="doc_text">
-<p>Previously announced in the 2.4, 2.5, and 2.6 LLVM releases, the Clang project also
-includes an early stage static source code analysis tool for <a
-href="http://clang.llvm.org/StaticAnalysis.html">automatically finding bugs</a>
-in C and Objective-C programs. The tool performs checks to find
-bugs that occur on a specific path within a program.</p>
+<p>The <a href="http://clang-analyzer.llvm.org/">Clang Static Analyzer</a>
+ project is an effort to use static source code analysis techniques to
+ automatically find bugs in C and Objective-C programs (and hopefully <a
+ href="http://clang-analyzer.llvm.org/dev_cxx.html">C++ in the
+ future</a>!). The tool is very good at finding bugs that occur on specific
+ paths through code, such as on error conditions.</p>
-<p>In the LLVM 2.7 time-frame, the analyzer core has sprouted legs and...</p>
+<p>In the LLVM 2.8 time-frame,
+</p>
</div>
implementation of the CLI) using LLVM for static and just-in-time
compilation.</p>
-<p>
-With the release of LLVM 2.7, VMKit has shifted to a great framework for writing
-virtual machines. VMKit now offers precise and efficient garbage collection with
-multi-threading support, thanks to the MMTk memory management toolkit, as well
-as just in time and ahead of time compilation with LLVM. The major changes in
-VMKit 0.27 are:</p>
+<p>With the release of LLVM 2.8, ...</p>
-<ul>
-
-<li>Garbage collection: VMKit now uses the MMTk toolkit for garbage collectors.
- The first collector to be ported is the MarkSweep collector, which is precise,
- and drastically improves the performance of VMKit.</li>
-<li>Line number information in the JVM: by using the debug metadata of LLVM, the
- JVM now supports precise line number information, useful when printing a stack
- trace.</li>
-<li>Interface calls in the JVM: we implemented a variant of the Interface Method
- Table technique for interface calls in the JVM.
-</li>
-
-</ul>
</div>
<p>
All of the code in the compiler-rt project is available under the standard LLVM
-License, a "BSD-style" license. 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>
</p>
<p>
-DragonEgg is a new project which is seeing its first release with llvm-2.7.
+2.8 status here.
</p>
</div>
<div class="doc_text">
<p>
-The LLVM Machine Code (MC) Toolkit project is ...
-</p>
-
-<p>
-MC Disassembler (with blog post), MCInstPrinter. Many X86 backend and AsmPrinter simplifications
-Can transcode from GAS to intel syntax with "llvm-mc foo.s -output-asm-variant=1"
+The LLVM Machine Code (aka MC) sub-project of LLVM was created to solve a number
+of problems in the realm of assembly, disassembly, object file format handling,
+and a number of other related areas that CPU instruction-set level tools work
+in. It is a sub-project of LLVM which provides it with a number of advantages
+over other compilers that do not have tightly integrated assembly-level tools.
+For a gentle introduction, please see the <a
+href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">Intro to the
+LLVM MC Project Blog Post</a>.
</p>
+<p>2.8 status here</p>
</div>
<!-- *********************************************************************** -->
<div class="doc_section">
- <a name="externalproj">External Open Source Projects Using LLVM 2.7</a>
+ <a name="externalproj">External Open Source Projects Using LLVM 2.8</a>
</div>
<!-- *********************************************************************** -->
<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>
+ projects that have already been updated to work with LLVM 2.8.</p>
</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 class="doc_section">
+ <a name="whatsnew">What's New in LLVM 2.8?</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>This release includes a huge number of bug fixes, performance tweaks and
+minor improvements. Some of the major improvements and new features are listed
+in this section.
</p>
-</div>
-
-<!--=========================================================================-->
-<div class="doc_subsection">
-<a name="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>
+<a name="orgchanges">LLVM Community Changes</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_section">
- <a name="whatsnew">What's New in LLVM 2.7?</a>
-</div>
-<!-- *********************************************************************** -->
-
-<div class="doc_text">
-
-<p>This release includes a huge number of bug fixes, performance tweaks and
-minor improvements. Some of the major improvements and new features are listed
-in this section.
-</p>
-
-<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>
<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,
- which aims to rework our handling of low-level machine code. 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 you has made
- substantially more progress on LLVM mainline. You can read more about this
- in the <a href="http://blog.llvm.org/2010/04/intro-to-llvm-mc-project.html">
- Intro to the LLVM MC Project Blog Post</a>.
-</li>
-
+<li>.</li>
</ul>
</div>
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 2.7 has pre-alpha support for <a
- href="http://llvm.org/docs/LangRef.html#t_union">unions in LLVM IR</a>.
- Unfortuantely, 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>
+
+<li>LLVM 2.8 changes the internal order of operands in <a
+ href="http://llvm.org/doxygen/classllvm_1_1InvokeInst.html"><tt>InvokeInst</tt></a>
+ and <a href="http://llvm.org/doxygen/classllvm_1_1CallInst.html"><tt>CallInst</tt></a>.
+ To be portable across releases, resort to <tt>CallSite</tt> and the
+ high-level accessors, such as <tt>getCalledValue</tt> and <tt>setUnwindDest</tt>.
</li>
+
</ul>
</div>
<ul>
-<li>The inliner reuses 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 what the 'native' integer data types a for the target,
- which allows various optimizations to use. 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
- a 32-bit chip).</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>As usual, there are countless minor optimization improvements and bug fixes,
- and the default pass ordering has been tweaked for improved optimization
- effectiveness.</li>
+<li></li>
</ul>
<div class="doc_text">
<ul>
-<li>The JIT now supports generating debug information, which is compatible with
-the new GDB 7.0 (and later) interfaces for registering debug info for
-dynamically generated code.</li>
-
-<li>The JIT now <a
-href="http://llvm.org/viewvc/llvm-project?view=rev&revision=85295">defaults
-to compiling eagerly</a> to avoid a race condition in the lazy JIT.
-Clients that still want the lazy JIT can switch it on by calling
-<tt>ExecutionEngine::DisableLazyCompilation(false)</tt>.</li>
-
-<li>It is now possible to create more than one JIT instance in the same process.
-These JITs can generate machine code in parallel,
-although <a href="http://llvm.org/docs/ProgrammersManual.html#jitthreading">you
-still have to obey the other threading restrictions</a>.</li>
+<li></li>
</ul>
it run faster:</p>
<ul>
-<li>New instruction selector [blog post?].</li>
-<li>New LSR with "full strength reduction" mode. Description?</li>
-<li>Code generator MC'ized except for debug info and EH.</li>
-<li>New CodeGen Level CSE</li>
-<li>Combiner-AA improvements, why not on by default?</li>
-<li>Pre-regalloc tail duplication</li>
-<li>Codegen level OptimizeExtsPass pass, takes advantage of x86 subregs. </li>
-<li>Support for the GCC option -fno-schedule-insns</li>
-<li>Non-temporal load/store, only implemented on X86, see LangRef.html#i_load.</li>
-<li>MachineSSAUpdater.h</li>
-<li>X86 and XCore supports returning arbitrary return values, returning too many values is
- supported by returning through a hidden pointer.</li>
-<li>verbose-asm now produces information about spill slots and loop nests</li>
-<li>GHC Haskell ABI / calling conv support.</li>
-<li>Many improvements to debug info</li>
+<li>MachO writer works.</li>
</ul>
</div>
</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>PostRA scheduler for X86? FIXME: is this on by default in 2.7?</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>
<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 using register scavenging for stack
- object address materialization.(FIXME: WHAT BENEFIT DOES THIS PROVIDE?)</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></li>
+
</ul>
</p>
<ul>
-<li>The optimizer uses the new CodeMetrics class to measure the size of code.
- Various passes that use thing (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 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 through various passes (e.g. jump threading, lcssa, loop rotate,
- etc) for doing this sort of thing. The code generator has an 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>
<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, before 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>
<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>Just about everything has been converted to use raw_ostream instead of
- std::ostream.</li>
-<li>llvm/ADT/iterator.h has been removed, just use <iterator>
- instead.</li>
-<li>The Streams.h file and "DOUT" got removed, use "DEBUG(errs() << ...);"
- instead.</li>
-<li><tt>ModuleProvider</tt> has been <a
-href="http://llvm.org/viewvc/llvm-project?view=rev&revision=94686">removed</a>
-and its methods moved to <tt>Module</tt> and <tt>GlobalValue</tt>.
-Most clients can remove uses of <tt>ExistingModuleProvider</tt>,
-replace <tt>getBitcodeModuleProvider</tt> with
-<tt>getLazyBitcodeModule</tt>, and pass their <tt>Module</tt> to
-functions that used to accept <tt>ModuleProvider</tt>. Clients who
-wrote their own <tt>ModuleProvider</tt>s will need to derive from
-<tt>GVMaterializer</tt> instead and use
-<tt>Module::setMaterializer</tt> to attach it to a
-<tt>Module</tt>.</li>
-
-<li><tt>GhostLinkage</tt> has given up the ghost.
-<tt>GlobalValue</tt>s that have not yet been read from their backing
-storage have the same linkage they will have after being read in.
-Clients must replace calls to
-<tt>GlobalValue::hasNotBeenReadFromBitcode</tt> with
-<tt>GlobalValue::isMaterializable</tt>.</li>
-
-<li>The <tt>llvm/Support/DataTypes.h</tt> header has moved
-to <tt>llvm/System/DataTypes.h</tt>.</li>
-
-<li>The <tt>isInteger</tt>, <tt>isIntOrIntVector</tt>, <tt>isFloatingPoint</tt>,
-<tt>isFPOrFPVector</tt> and <tt>isFPOrFPVector</tt> methods have been renamed
-<tt>isIntegerTy</tt>, <tt>isIntOrIntVectorTy</tt>, <tt>isFloatingPointTy</tt>,
-<tt>isFPOrFPVectorTy</tt> and <tt>isFPOrFPVectorTy</tt> respectively.</li>
</ul>
</div>
<li>Intel and AMD machines (IA32, X86-64, AMD64, EMT-64) running Red Hat
Linux, Fedora Core, FreeBSD and AuroraUX (and probably other unix-like
systems).</li>
-<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit
+<li>PowerPC and X86-based Mac OS X systems, running 10.4 and above in 32-bit
and 64-bit modes.</li>
<li>Intel and AMD machines running on Win32 using MinGW libraries (native).</li>
<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
<ul>
<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430, SystemZ and MicroBlaze
backends are experimental.</li>
-<li>The <tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
- supported value for this option. The MachO writer is experimental, and
- works much better in mainline SVN.</li>
+<li><tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
+ supported value for this option. XXX Update me</li>
</ul>
</div>
all <a href="http://llvm.org/PR879">inline assembly that uses the X86
floating point stack</a>. It supports the 'f' and 't' constraints, but not
'u'.</li>
- <li>The X86 backend generates inefficient floating point code when configured
- to generate code for systems that don't have SSE2.</li>
<li>Win64 code generation wasn't widely tested. Everything should work, but we
expect small issues to happen. Also, llvm-gcc cannot build the mingw64
- runtime currently due
- to <a href="http://llvm.org/PR2255">several</a>
- <a href="http://llvm.org/PR2257">bugs</a> and due to lack of support for
- the
- 'u' inline assembly constraint and for X87 floating point inline assembly.</li>
+ runtime currently due to lack of support for the 'u' inline assembly
+ constraint and for X87 floating point inline assembly.</li>
<li>The X86-64 backend does not yet support the LLVM IR instruction
- <tt>va_arg</tt>. Currently, the llvm-gcc and front-ends support variadic
+ <tt>va_arg</tt>. Currently, front-ends support variadic
argument constructs on X86-64 by lowering them manually.</li>
</ul>
supported on some targets (these are used when you take the address of a
nested function).</p>
-<p>If you run into GCC extensions which are not supported, please let us know.
-</p>
-
</div>
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