<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link rel="stylesheet" href="llvm.css" type="text/css">
- <title>LLVM 2.3 Release Notes</title>
+ <title>LLVM 2.7 Release Notes</title>
</head>
<body>
-<div class="doc_title">LLVM 2.3 Release Notes</div>
-
+<div class="doc_title">LLVM 2.7 Release Notes</div>
+
<ol>
<li><a href="#intro">Introduction</a></li>
- <li><a href="#whatsnew">What's New?</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="GettingStarted.html">Installation Instructions</a></li>
<li><a href="#portability">Portability and Supported Platforms</a></li>
- <li><a href="#knownproblems">Known Problems</a>
+ <li><a href="#knownproblems">Known Problems</a></li>
<li><a href="#additionalinfo">Additional Information</a></li>
</ol>
<div class="doc_author">
- <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
+ <p>Written by the <a href="http://llvm.org">LLVM Team</a></p>
</div>
-<!-- Done through Week-of-Mon-20080324.txt -->
+<h1 style="color:red">These are in-progress notes for the upcoming LLVM 2.7
+release.<br>
+You may prefer the
+<a href="http://llvm.org/releases/2.6/docs/ReleaseNotes.html">LLVM 2.6
+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 2.3. Here we describe the status of LLVM, including
-major improvements from the previous release and any known problems. All LLVM
-releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
-releases web site</a>.</p>
+<p>This document contains the release notes for the LLVM Compiler
+Infrastructure, release 2.7. 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>
<p>For more information about LLVM, including information about the latest
release, please check out the <a href="http://llvm.org/">main LLVM
web site</a>. If you have questions or comments, the <a
-href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
-list</a> is a good place to send them.</p>
+href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM Developer's Mailing
+List</a> is a good place to send them.</p>
-<p>Note that if you are reading this file from a Subversion checkout or the
+<p>Note that if you are reading this file from a Subversion checkout or the
main LLVM web page, this document applies to the <i>next</i> release, not the
-current one. To see the release notes for a specific releases, please see the
+current one. To see the release notes for a specific release, please see the
<a href="http://llvm.org/releases/">releases page</a>.</p>
</div>
+
+
+<!--
+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.
+ ABCD, SCCVN, GEPSplitterPass
+ MSIL backend?
+ AndersAA -> Unsupported, zap after branch.
+-->
+
+
+<!-- Features that need text if they're finished for 2.7:
+ gcc plugin.
+ strong phi elim
+ variable debug info for optimized code
+ postalloc scheduler: anti dependence breaking, hazard recognizer?
+ 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.
+ 2.7 eliminates ADT/iterator.h
+ -->
+
+ <!-- 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_section">
- <a name="whatsnew">What's New?</a>
+ <a name="subproj">Sub-project Status Update</a>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
-
-<p>This is the fourteenth public release of the LLVM Compiler Infrastructure.
-It includes a large number of features and refinements from LLVM 2.2.</p>
+<p>
+The LLVM 2.7 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
+development. Here we include updates on these subprojects.
+</p>
</div>
-<!-- Unfinished features in 2.3:
- Machine LICM
- Machine Sinking
- LegalizeDAGTypes
- -->
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="changes">Major Changes in LLVM 2.3</a>
+<a name="clang">Clang: C/C++/Objective-C Frontend Toolkit</a>
</div>
<div class="doc_text">
-<p>LLVM 2.2 was the last LLVM release to support llvm-gcc 4.0 and llvm-upgrade.
-llvm-gcc 4.0 has been replaced with llvm-gcc 4.2. llvm-upgrade was useful for
-upgrading LLVM 1.9 files to LLVM 2.x syntax, but you can always use a previous
-LLVM release to do this. One nice impact of this is that the LLVM regressionn
-test suite no longer depends on llvm-upgrade, which makes it run faster.</p>
+<p>The <a href="http://clang.llvm.org/">Clang project</a> is ...</p>
-<p>LLVM 2.3 renames the LLVMBuilder and LLVMFoldingBuilder classes to
- IRBuilder.</p>
+<p>In the LLVM 2.7 time-frame, the Clang team has made many improvements:</p>
+<ul>
+<li>...</li>
+</ul>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="majorfeatures">Major New Features</a>
+<a name="clangsa">Clang Static Analyzer</a>
</div>
<div class="doc_text">
-<p>LLVM 2.3 includes several major new capabilities:</p>
+<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>
-<ul>
-<li>Multiple Return Value Support</li>
+<p>In the LLVM 2.7 time-frame, the analyzer core has ...</p>
+
+</div>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="vmkit">VMKit: JVM/CLI Virtual Machine Implementation</a>
+</div>
-<li><p>LLVM 2.3 includes a complete reimplementation of the "llvmc" tool. It is
-designed to overcome several problems of the original llvmc and to provide a
-superset of the features as the 'gcc' driver.</p>
+<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 Machine (Microsoft .NET is an
+implementation of the CLI) using LLVM for static and just-in-time
+compilation.</p>
-<p>The main features of llvmc2 is:</p>
+<p>
+VMKit version ?? builds with LLVM 2.7 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>Extended handling of command line options and smart rules for
-dispatching them to different tools.</li>
-<li>Flexible (and extensible) rules for defining different tools.</li>
-<li>The different intermediate steps performed by tools are represented
-as edged in the abstract graph.</li>
-</l>The 'language' for driver behaviour definition is tablegen and thus
-it's relatively easy to add new features.</li>
-<li>The definition of driver is transformed into set of C++ classes, thus
-no runtime interpretation is needed.</li>
+
+<li>...</li>
+
</ul>
+</div>
-</li>
-<li>Reimplemented <a href="LinkTimeOptimization.html">LTO interface</a> in
- C.</li>
+<!--=========================================================================-->
+<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>
-<li>kaleidoscope tutorial in ocaml.</li>
+</div>
-</ul>
+<!--=========================================================================-->
+<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">DragonEgg: GCC-4.5 as an LLVM frontend</a>
+</div>
+
+<div class="doc_text">
+<p>
+The goal of <a href="http://dragonegg.llvm.org/">DragonEgg</a> is to make
+gcc-4.5 act like llvm-gcc without requiring any gcc modifications whatsoever.
+<a href="http://dragonegg.llvm.org/">DragonEgg</a> is a shared library (dragonegg.so)
+that is loaded by gcc at runtime. It ...
+</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 ...
+</p>
+
+</div>
+
+
+<!-- *********************************************************************** -->
+<div class="doc_section">
+ <a name="externalproj">External Open Source Projects Using LLVM 2.7</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 2.7.</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>
+</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 ??? and later have been tested and are known to work with
+LLVM 2.7 (and continue to work with older LLVM releases >= 2.3 as well).
+</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="frontends">llvm-gcc 4.2 Improvements and Clang</a>
+<a name="ldc">LLVM D Compiler</a>
</div>
<div class="doc_text">
+<p>
+<a href="http://www.dsource.org/projects/ldc">LDC</a> is an implementation of
+the D Programming Language using the LLVM optimizer and code generator.
+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 bug fixes and better x86-64 support. This has allowed
+some major improvements in LDC, getting it much closer to being as
+fully featured as the original DMD compiler from DigitalMars.
+</p>
+</div>
-<p>LLVM 2.3 fully supports llvm-gcc 4.2 front-end.</p>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="RoadsendPHP">Roadsend PHP</a>
+</div>
-<p>llvm-gcc 4.2 includes numerous fixes to better support the Objective-C
-front-end. Objective-C now works very well on Mac OS/X.</p>
+<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>
-<p>llvm-gcc 4.2 includes many other fixes which improve conformance with the
-relevant parts of the GCC testsuite.</p>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="UnladenSwallow">Unladen Swallow</a>
+</div>
-<p>The <a href="http://clang.llvm.org/">clang project</a> is an effort to build
-a set of new 'llvm native' front-end technologies for the LLVM optimizer
-and code generator. Currently, its C and Objective-C support is maturing
-nicely, and it has advanced source-to-source analysis and transformation
-capabilities. If you are interested in building source-level tools for C and
-Objective-C (and eventually C++), you should take a look. However, note that
-clang is not an official part of the LLVM 2.3 release. If you are interested in
-this project, please see its <a href="http://clang.llvm.org/">web site</a>.</p>
+<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="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>
+</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="coreimprovements">LLVM Core Improvements</a>
+<a name="icedtea">IcedTea Java Virtual Machine Implementation</a>
</div>
<div class="doc_text">
-<p>New features include:
+<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>
+</div>
-Common linkage?
-Atomic operation support, Alpha, X86, X86-64, PowerPC. "__sync_synchronize"
+<!-- *********************************************************************** -->
+<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>
+
+</div>
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="majorfeatures">Major New Features</a>
+</div>
+
+<div class="doc_text">
+
+<p>LLVM 2.7 includes several major new capabilities:</p>
<ul>
-<li>The C and Ocaml bindings have received additional improvements. The
-bindings now cover pass managers, several transformation passes, iteration
-over the LLVM IR, target data, and parameter attribute lists.</li>
+<li>...</li>
</ul>
-
+
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="codegen">Code Generator Improvements</a>
+<a name="coreimprovements">LLVM IR and Core Improvements</a>
</div>
<div class="doc_text">
-
-<p>We put a significant amount of work into the code generator infrastructure,
-which allows us to implement more aggressive algorithms and make it run
-faster:</p>
+<p>LLVM IR has several new features for better support of new targets and that
+expose new optimization opportunities:</p>
<ul>
-<li>MemOperand in the code generator: describe me!.</li>
-<li>i128 support and APInt through most of codegen.</li>
-<li>Several compile time speedups for code with large basic blocks.</li>
+<li>...</li>
</ul>
</div>
<div class="doc_text">
-<p>In addition to a huge array of bug fixes and minor performance tweaks, the
-LLVM 2.3 optimizers support a few major enhancements:</p>
+<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>Loop index set splitting on by default: describe me.</li>
-<li>LLVM includes a new memcpy optimization pass which optimizes out dead
-memcpy calls, unneeded copies of aggregates, and handles the return slot
-optimization. The LLVM optimizer now notices long sequences of consequtive
-stores and merges them into memcpy's where profitable.</li>
+<li>...</li>
+
+</ul>
+
+</div>
+
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="executionengine">Interpreter and JIT Improvements</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+<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>
</ul>
</div>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="codegen">Target Independent Code Generator Improvements</a>
+</div>
+
+<div class="doc_text">
+
+<p>We have put a significant amount of work into the code generator
+infrastructure, which allows us to implement more aggressive algorithms and make
+it run faster:</p>
+
+<ul>
+
+<li>...</li>
+</ul>
+</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="x86specific">X86/X86-64 Specific Improvements</a>
+<a name="x86">X86-32 and X86-64 Target Improvements</a>
</div>
<div class="doc_text">
-<p>New target-specific features include:
+<p>New features of the X86 target include:
</p>
<ul>
-<li>llvm-gcc's X86-64 ABI conformance is far improved, particularly in the
- area of passing and returning structures by value. llvm-gcc Compiled code
- now interoperates very well on X86-64 systems with other compilers.</li>
-
-<li>The LLVM X86 backend now supports the support SSE 4.1 instruction set, and
- the llvm-gcc 4.2 front-end supports the SSE 4.1 compiler builtins.</li>
-
-<li>The X86 backend now does a number of optimizations that aim to avoid
- converting numbers back and forth from SSE registers to the X87 floating
- point stack.</li>
-
-<li>The X86 backend supports stack realignment, which is particularly useful for
- vector code on OS's without 16-byte aligned stacks.</li>
-<li>The X86 backend now supports the "sseregparm" options in GCC, which allow
- functions to be tagged as passing floating point values in SSE
- registers.</li>
+<li>...</li>
-<li>Trampolines (taking the address of a nested function) now work on
- Linux/x86-64.</li>
-
-<li><tt>__builtin_prefetch</tt> is now compiled into the appropriate prefetch
- instructions instead of being ignored.</li>
+</ul>
+
+</div>
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="pic16">PIC16 Target Improvements</a>
+</div>
+
+<div class="doc_text">
+<p>New features of the PIC16 target include:
+</p>
+<ul>
+<li>...</li>
+</ul>
+
+<p>Things not yet supported:</p>
+
+<ul>
+<li>Variable arguments.</li>
+<li>Interrupts/programs.</li>
</ul>
-
+
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="targetspecific">Other Target Specific Improvements</a>
+<a name="ARM">ARM Target Improvements</a>
</div>
<div class="doc_text">
-<p>New target-specific features include:
+<p>New features of the ARM target include:
</p>
<ul>
-<li>The LLVM C backend now supports vectors code.</li>
-
+<li>...</li>
</ul>
-
+
+
+</div>
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="OtherTarget">Other Target Specific Improvements</a>
</div>
+<div class="doc_text">
+<p>New features of other targets include:
+</p>
+
+<ul>
+<li>...</li>
+</ul>
+</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="otherimprovements">Other Improvements</a>
+<a name="newapis">New Useful APIs</a>
</div>
<div class="doc_text">
-<p>New features include:
+
+<p>This release includes a number of new APIs that are used internally, which
+ may also be useful for external clients.
</p>
<ul>
-<li>LLVM now builds with GCC 4.3.</li>
-<li>llvm2cpp tool was moved into llc, use llc -march=cpp</li>
+<li>...</li>
</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>...</li>
+</ul>
+
+</div>
+
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="changes">Major Changes and Removed Features</a>
+</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
+from the previous release.</p>
+
+<ul>
+<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>
+</ul>
+
+
+<p>In addition, many APIs have changed in this release. Some of the major LLVM
+API changes are:</p>
+
+<ul>
+<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>FIXME: Debug info has been totally redone. Add pointers to new APIs. Substantial caveats about compatibility of .ll and .bc files.</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>
+
+
+
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="portability">Portability and Supported Platforms</a>
<p>LLVM is known to work on the following platforms:</p>
<ul>
-<li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
- (and probably other unix-like systems).</li>
-<li>PowerPC and X86-based Mac OS X systems, running 10.3 and above in 32-bit and
- 64-bit modes.</li>
+<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
+ 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
support is available for native builds with Visual C++).</li>
-<li>Sun UltraSPARC workstations running Solaris 8.</li>
+<li>Sun x86 and AMD64 machines running Solaris 10, OpenSolaris 0906.</li>
<li>Alpha-based machines running Debian GNU/Linux.</li>
-<li>Itanium-based machines running Linux and HP-UX.</li>
</ul>
<p>The core LLVM infrastructure uses GNU autoconf to adapt itself
<div class="doc_text">
-<p>This section contains all known problems with the LLVM system, listed by
-component. As new problems are discovered, they will be added to these
-sections. If you run into a problem, please check the <a
+<p>This section contains significant known problems with the LLVM system,
+listed by component. If you run into a problem, please check the <a
href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
there isn't already one.</p>
+<ul>
+<li>The llvm-gcc bootstrap will fail with some versions of binutils (e.g. 2.15)
+ with a message of "<tt><a href="http://llvm.org/PR5004">Error: can not do 8
+ byte pc-relative relocation</a></tt>" when building C++ code. We intend to
+ fix this on mainline, but a workaround is to upgrade to binutils 2.17 or
+ later.</li>
+
+<li>LLVM will not correctly compile on Solaris and/or OpenSolaris
+using the stock GCC 3.x.x series 'out the box',
+See: <a href="GettingStarted.html#brokengcc">Broken versions of GCC and other tools</a>.
+However, A <a href="http://pkg.auroraux.org/GCC">Modern GCC Build</a>
+for x86/x86-64 has been made available from the third party AuroraUX Project
+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, and MIPS backends are experimental.</li>
-<li>The LLC "<tt>-filetype=asm</tt>" (the default) is the only supported
- value for this option.</li>
+<li>The MSIL, Alpha, SPU, MIPS, PIC16, Blackfin, MSP430 and SystemZ backends are
+ experimental.</li>
+<li>The <tt>llc</tt> "<tt>-filetype=asm</tt>" (the default) is the only
+ supported value for this option. The ELF writer is experimental.</li>
+<li>The implementation of Andersen's Alias Analysis has many known bugs.</li>
</ul>
</div>
<div class="doc_text">
<ul>
-<li>The X86 backend does not yet support 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>The X86 backend does not yet support
+ 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>
+ <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
+ argument constructs on X86-64 by lowering them manually.</li>
</ul>
</div>
<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>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>
<div class="doc_text">
<ul>
-<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
+<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32); it does not
support the 64-bit SPARC ABI (-m64).</li>
</ul>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="alpha-be">Known problems with the Alpha back-end</a>
+ <a name="mips-be">Known problems with the MIPS back-end</a>
</div>
<div class="doc_text">
<ul>
-
-<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
-appropriate nops inserted to ensure restartability.</li>
-
+<li>64-bit MIPS targets are not supported yet.</li>
</ul>
+
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="ia64-be">Known problems with the IA64 back-end</a>
+ <a name="alpha-be">Known problems with the Alpha back-end</a>
</div>
<div class="doc_text">
<ul>
-<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
-made where the argument is not 16-byte aligned, as required on IA64. (Strictly
-speaking this is not a bug in the IA64 back-end; it will also be encountered
-when building C++ programs using the C back-end.)</li>
-
-<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
-ABI compliant layout of v-tables</a>. In particular, it just stores function
-pointers instead of function descriptors in the vtable. This bug prevents
-mixing C++ code compiled with LLVM with C++ objects compiled by other C++
-compilers.</li>
-
-<li>There are a few ABI violations which will lead to problems when mixing LLVM
-output with code built with other compilers, particularly for floating-point
-programs.</li>
-
-<li>Defining vararg functions is not supported (but calling them is ok).</li>
+<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
+appropriate nops inserted to ensure restartability.</li>
-<li>The Itanium backend has bitrotted somewhat.</li>
</ul>
-
</div>
<!-- ======================================================================= -->
inline assembly code</a>.</li>
<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
- C++ code compiled with LLC or native compilers.</li>
+ C++ code compiled with <tt>llc</tt> or native compilers.</li>
<li>The C backend does not support all exception handling constructs.</li>
+<li>The C backend does not support arbitrary precision integers.</li>
</ul>
</div>
<a name="c-fe">Known problems with the llvm-gcc C front-end</a>
</div>
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">Bugs</div>
-
<div class="doc_text">
-<p>llvm-gcc does not currently support <a href="http://llvm.org/PR869">Link-Time
-Optimization</a> on most platforms "out-of-the-box". Please inquire on the
-llvmdev mailing list if you are interested.</p>
-
<p>The only major language feature of GCC not supported by llvm-gcc is
the <tt>__builtin_apply</tt> family of builtins. However, some extensions
are only supported on some targets. For example, trampolines are only
- supported on some targets, which are used when you take the address of a
- nested function.</p>
+ 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>
itself, Qt, Mozilla, etc.</p>
<ul>
-<li>Exception handling works well on the X86 and PowerPC targets, including
-x86-64 darwin. This works when linking to a libstdc++ compiled by GCC. It is
-supported on x86-64 linux, but that is disabled by default in this release.</li>
+<li>Exception handling works well on the X86 and PowerPC targets. Currently
+ only Linux and Darwin targets are supported (both 32 and 64 bit).</li>
</ul>
</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
+</div>
+
+<div class="doc_text">
+<ul>
+<li>Fortran support generally works, but there are still several unresolved bugs
+ in <a href="http://llvm.org/bugs/">Bugzilla</a>. Please see the
+ tools/gfortran component for details.</li>
+</ul>
+</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
</div>
<div class="doc_text">
-The llvm-gcc 4.2 Ada compiler works fairly well, however this is not a mature
-technology and problems should be expected.
+The llvm-gcc 4.2 Ada compiler works fairly well; however, this is not a mature
+technology, and problems should be expected.
<ul>
-<li>The Ada front-end currently only builds on x86-32. This is mainly due
-to lack of trampoline support (pointers to nested functions) on other platforms,
-however it <a href="http://llvm.org/PR2006">also fails to build on x86-64</a>
+<li>The Ada front-end currently only builds on X86-32. This is mainly due
+to lack of trampoline support (pointers to nested functions) on other platforms.
+However, it <a href="http://llvm.org/PR2006">also fails to build on X86-64</a>
which does support trampolines.</li>
<li>The Ada front-end <a href="http://llvm.org/PR2007">fails to bootstrap</a>.
-Workaround: configure with --disable-bootstrap.</li>
-<li>The c380004 and <a href="http://llvm.org/PR2010">c393010</a> ACATS tests
-fail (c380004 also fails with gcc-4.2 mainline).</li>
-<li>Many gcc specific Ada tests continue to crash the compiler.</li>
-<li>The -E binder option (exception backtraces)
+This is due to lack of LLVM support for <tt>setjmp</tt>/<tt>longjmp</tt> style
+exception handling, which is used internally by the compiler.
+Workaround: configure with <tt>--disable-bootstrap</tt>.</li>
+<li>The c380004, <a href="http://llvm.org/PR2010">c393010</a>
+and <a href="http://llvm.org/PR2421">cxg2021</a> ACATS tests fail
+(c380004 also fails with gcc-4.2 mainline).
+If the compiler is built with checks disabled then <a href="http://llvm.org/PR2010">c393010</a>
+causes the compiler to go into an infinite loop, using up all system memory.</li>
+<li>Some GCC specific Ada tests continue to crash the compiler.</li>
+<li>The <tt>-E</tt> binder option (exception backtraces)
<a href="http://llvm.org/PR1982">does not work</a> and will result in programs
-crashing if an exception is raised. Workaround: do not use -E.</li>
+crashing if an exception is raised. Workaround: do not use <tt>-E</tt>.</li>
<li>Only discrete types <a href="http://llvm.org/PR1981">are allowed to start
or finish at a non-byte offset</a> in a record. Workaround: do not pack records
or use representation clauses that result in a field of a non-discrete type
starting or finishing in the middle of a byte.</li>
-<li>The lli interpreter <a href="http://llvm.org/PR2009">considers 'main'
-as generated by the Ada binder to be invalid</a>.
-Workaround: hand edit the file to use pointers for argv and envp rather than
-integers.</li>
-<li>The -fstack-check option <a href="http://llvm.org/PR2008">is ignored</a>.</li>
+<li>The <tt>lli</tt> interpreter <a href="http://llvm.org/PR2009">considers
+'main' as generated by the Ada binder to be invalid</a>.
+Workaround: hand edit the file to use pointers for <tt>argv</tt> and
+<tt>envp</tt> rather than integers.</li>
+<li>The <tt>-fstack-check</tt> option <a href="http://llvm.org/PR2008">is
+ignored</a>.</li>
</ul>
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="fortran-fe">Known problems with the llvm-gcc Fortran front-end</a>
+ <a name="ocaml-bindings">Known problems with the O'Caml bindings</a>
</div>
<div class="doc_text">
-<ul>
-<li>The llvm-gcc 4.2 gfortran front-end supports a broad range of Fortran code, but does
-<a href="http://llvm.org/PR1971">not support EQUIVALENCE yet</a>.</li>
-</ul>
+<p>The <tt>Llvm.Linkage</tt> module is broken, and has incorrect values. Only
+<tt>Llvm.Linkage.External</tt>, <tt>Llvm.Linkage.Available_externally</tt>, and
+<tt>Llvm.Linkage.Link_once</tt> 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>
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