<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link rel="stylesheet" href="llvm.css" type="text/css">
- <title>LLVM 2.0 Release Notes</title>
+ <title>LLVM 2.1 Release Notes</title>
</head>
<body>
-<div class="doc_title">LLVM 2.0 Release Notes</div>
+<div class="doc_title">LLVM 2.1 Release Notes</div>
<ol>
<li><a href="#intro">Introduction</a></li>
<div class="doc_text">
<p>This document contains the release notes for the LLVM compiler
-infrastructure, release 2.0. Here we describe the status of LLVM, including any
-known problems and major improvements from the previous release. All LLVM
+infrastructure, release 2.1. 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>.
+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
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 CVS 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 the current or previous releases, see the <a
-href="http://llvm.org/releases/">releases page</a>.</p>
+<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
+<a href="http://llvm.org/releases/">releases page</a>.</p>
</div>
<div class="doc_text">
-<p>This is the eleventh public release of the LLVM Compiler Infrastructure.
-Being the first major release since 1.0, this release is different in several
-ways from our previous releases:</p>
-
-<ol>
-<li>We took this as an opportunity to
-break backwards compatibility with the LLVM 1.x bytecode and .ll file format.
-If you have LLVM 1.9 .ll files that you would like to upgrade to LLVM 2.x, we
-recommend the use of the stand alone <a href="#llvm-upgrade">llvm-upgrade</a>
-tool (which is included with 2.0). We intend to keep compatibility with .ll
-and .bc formats within the 2.x release series, like we did within the 1.x
-series.</li>
-<li>There are several significant change to the LLVM IR and internal APIs, such
- as a major overhaul of the type system, the completely new bitcode file
- format, etc.</li>
-<li>We designed the release around a 6 month release cycle instead of the usual
- 3-month cycle. This gave us extra time to develop and test some of the
- more invasive features in this release.</li>
-<li>LLVM 2.0 no longer supports the llvm-gcc3 front-end.</li>
-</ol>
-
-<p>Note that while this is a major version bump, this release has been
- extensively tested on a wide range of software. It is easy to say that this
- is our best release yet, in terms of both features and correctness.</p>
+<p>This is the twelfth public release of the LLVM Compiler Infrastructure.
+It includes many features and refinements from LLVM 2.0.</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="newfeatures">New Features in LLVM 2.0</a>
+<a name="frontends">New Frontends</a>
</div>
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="majorchanges">Major Changes</a></div>
<div class="doc_text">
-<p>blah
-</p>
-
-<ul>
-
-<li>llvm-gcc3 is now officially unsupported. Users are required to
- upgrade to llvm-gcc4. llvm-gcc4 includes many features over
- llvm-gcc3, is faster, and is much easier to build.</li>
-<li>Integer types are now completely signless. This means that we
- have types like i8/i16/i32 instead of ubyte/sbyte/short/ushort/int
- etc. LLVM operations that depend on sign have been split up into
- separate instructions (<a href="http://llvm.org/PR950">PR950</a>).</li>
+<p>LLVM 2.1 brings two new beta C front-ends. First, a new version of llvm-gcc
+based on GCC 4.2, innovatively called "llvm-gcc-4.2". This promises to bring
+FORTRAN and Ada support to LLVM as well as features like atomic builtins and
+OpenMP. None of these actually work yet, but don't let that stop you checking
+it out!</p>
-<li>Arbitrary bitwidth integers (e.g. i13, i36, i42, etc) are now
- supported in the LLVM IR and optimizations. However, neither llvm-gcc nor
- the native code generators support non-standard width integers
- (<a href="http://llvm.org/PR1043">PR1043</a>).</li>
+<p>Second, LLVM now includes its own native C and Objective-C front-end (C++ is
+in progress, but is not very far along) code named "<a
+href="http://clang.llvm.org/">clang</a>". This front-end has a number of great
+features, primarily aimed at source-level analysis and speeding up compile-time.
+At this point though, the LLVM Code Generator component is still very early in
+development, so it's mostly useful for people looking to build source-level
+analysis tools or source-to-source translators.</p>
-<li>'type planes' have been removed (<a href="http://llvm.org/PR411">PR411</a>).
- It is no longer possible to have two values with the same name in the
- same symbol table. This simplifies LLVM internals, allowing significant
- speedups.</li>
-
-<li>Global variables and functions in .ll files are now prefixed with
- @ instead of % (<a href="http://llvm.org/PR645">PR645</a>).</li>
-
-<li>The LLVM 1.x "bytecode" format has been replaced with a
- completely new binary representation, named 'bitcode'. Because we
- plan to maintain binary compatibility between LLVM 2.x ".bc" files,
- this is an important change to get right. Bitcode brings a number of
- advantages to the LLVM over the old bytecode format. It is denser
- (files are smaller), more extensible, requires less memory to read,
- is easier to keep backwards compatible (so LLVM 2.5 will read 2.0 .bc
- files), and has many other nice features.</li>
-
-<li>Support was added for alignment values on load and store
- instructions (<a href="http://www.llvm.org/PR400">PR400</a>). This
- allows the IR to express loads that are not
- sufficiently aligned (e.g. due to pragma packed) or to capture extra
- alignment information. </li>
+</div>
-<li>LLVM now has a new MSIL backend. llc - march=msil will now turn LLVM
- into MSIL (".net") bytecode. This is still fairly early development
- with a number of limitations.</li>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="optimizer">Optimizer Improvements</a>
+</div>
-<li>Support has been added for 'protected visibility' in ELF.</li>
+<div class="doc_text">
-<li>Thread Local Storage with the __thread keyword was implemented along
- with added codegen support for Linux on X86 and ARM.</li>
+<p>Some of the most noticable feature improvements this release have been in the
+optimizer, speeding it up and making it more aggressive. For example:</p>
-<li>ELF symbol aliases supported has been added.</li>
+<ul>
-<li>Added support for 'polymorphic intrinsics', allowing things like
- llvm.ctpop to work on arbitrary width integers.</li>
+<li>Owen Anderson wrote the new MemoryDependenceAnalysis pass, which provides
+ a lazy, caching layer on top of <a
+ href="AliasAnalysis.html">AliasAnalysis</a>. He then used it to rewrite
+ DeadStoreElimination which resulted in significantly better compile time in
+ common cases, </li>
+<li>Owen implemented the new GVN pass, which is also based on
+ MemoryDependenceAnalysis. This pass replaces GCSE/LoadVN in the standard
+ set of passes, providing more aggressive optimization at a some-what
+ improved compile-time cost.</li>
+<li>Owen implemented GVN-PRE, a partial redundancy elimination algorithm that
+ shares some details with the new GVN pass. It is still in need of compile
+ time tuning, and is not turned on by default.</li>
+<li>Devang merged ETForest and DomTree into a single easier to use data
+ structure. This makes it more obvious which datastructure to choose
+ (because there is only one) and makes the compiler more memory and time
+ efficient (less stuff to keep up-to-date).</li>
+<li>Nick Lewycky improved loop trip count analysis to handle many more common
+ cases.</li>
</ul>
-
+
</div>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="codegen">Code Generator Improvements</a>
+</div>
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="llvmgccfeatures">llvm-gcc
-Improvements</a></div>
<div class="doc_text">
-<p>New features include:
-</p>
+
+<p>One of the main focuses of this release was performance tuning and bug
+ fixing. In addition to these, several new major changes occurred:</p>
<ul>
-<li>Precompiled Headers (PCH) support has been implemented.</li>
-<li>Support for external weak linkage and hidden visibility has been added.</li>
+<li>Dale finished up the Tail Merging optimization in the code generator, and
+ enabled it by default. This produces smaller code that is also faster in
+ some cases.</li>
-<li>Packed structure types are now supported , which allows LLVM to express
- unaligned data more naturally.</li>
+<li>Christopher Lamb implemented support for virtual register sub-registers,
+ which can be used to better model many forms of subregisters. As an example
+ use, he modified the X86 backend to use this to model truncates and
+ extends more accurately (leading to better code).</li>
-<li>Inline assembly support has been improved and many bugs were fixed.
- The two large missing features are support for 80-bit floating point stack
- registers on X86 (<a href="http://llvm.org/PR879">PR879</a>), and support for inline asm in the C backend (<a href="http://llvm.org/PR802">PR802</a>).</li>
+<li>Dan Gohman changed the way we represent vectors before legalization,
+ significantly simplifying the SelectionDAG representation for these and
+ making the code generator faster for vector code.</li>
-<li>Ada support, such as nested functions, has been improved.</li>
+<li>Evan contributed a new target independent if-converter. While it is
+ target independent, so far only the ARM backend uses it.</li>
-<li>Tracking function parameter/result attributes is now possible.</li>
+<li>Evan rewrote the way the register allocator handles rematerialization,
+ allowing it to be much more effective on two-address targets like X86,
+ and taught it to fold loads away when possible (also a big win on X86).</li>
-<li>Its is now easier to configure llvm-gcc for linux.</li>
+<li>Dan Gohman contributed support for better alignment and volatility handling
+ in the code generator, and significantly enhanced alignment analysis for SSE
+ load/store instructions. With his changes, an insufficiently-aligned SSE
+ load instruction turns into <tt>movups</tt>, for example.</li>
-<li>Many enhancements have been added, such as improvements to NON_LVALUE_EXPR,
- arrays with non-zero base, structs with variable sized fields,
- VIEW_CONVERT_EXPR, CEIL_DIV_EXPR, and many other things.</li>
+<li>Duraid Madina contributed a new "bigblock" register allocator, and Roman
+ Levenstein contributed several big improvements. BigBlock is optimized for
+ code that uses very large basic blocks. It is slightly slower than the
+ "local" allocator, but produces much better code.</li>
-<li>Improved "attribute packed" support in the CFE, and handle many
- other obscure struct layout cases correctly.</li>
+<li>David Greene refactored the register allocator to split coalescing out from
+ allocation, making coalescers pluggable.</li>
</ul>
-
+
+</div>
+
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="targetspecific">Target Specific Improvements</a>
</div>
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="optimizer">Optimizer
-Improvements</a></div>
<div class="doc_text">
<p>New features include:
</p>
<ul>
-<li>The pass manager has been entirely rewritten, making it significantly
- smaller, simpler, and more extensible. Support has been added to run
- FunctionPasses interlaced with CallGraphSCCPasses.</li>
-
-<li>The -scalarrepl pass can now promote unions containing FP values into
- a register, it can also handle unions of vectors of the same size.</li>
-
-<li>The predicate simplifier pass has been improved, making it able to do
- simple value range propagation and eliminate more conditionals.</li>
-
-<li>There is a new new LoopPass class. The passmanager has been
- modified to support it, and all existing loop xforms have been
- converted to use it. </li>
-
-<li>There is a new loop rotation pass, which converts "for loops" into
- "do/while loops", where the condition is at the bottom of the loop.</li>
-
-<li>ModulePasses may now use the result of FunctionPasses.</li>
+<li>Bruno Cardoso Lopes contributed initial MIPS support. It is sufficient to
+ run many small programs, but is still incomplete and is not yet
+ fully performant.</li>
+
+<li>Bill Wendling added SSSE3 support to the X86 backend.</li>
-<li>The [Post]DominatorSet classes have been removed from LLVM and clients switched to use the far-more-efficient ETForest class instead. </li>
+<li>Nicholas Geoffray contributed improved linux/ppc ABI and JIT support.</li>
-<li>The ImmediateDominator class has also been removed, and clients have been switched to use DominatorTree instead.</li>
+<li>Dale Johannesen rewrote handling of 32-bit float values in the X86 backend
+ when using the floating point stack, fixing several nasty bugs.</li>
+<li>Dan contributed rematerialization support for the X86 backend, in addition
+ to several X86-specific micro optimizations.</li>
</ul>
</div>
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="codegen">Code
-Generator Enhancements</a></div>
+
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="llvmgccimprovements">llvm-gcc Improvements</a>
+</div>
<div class="doc_text">
-<p>
-New features include:
+<p>New features include:
</p>
<ul>
-<li>Support for Zero-cost DWARF exception handling has been added. It is mostly
- complete and just in need of continued bug fixes and optimizations at
- this point.</li>
-
-<li>Progress has been made on a direct Mach-o .o file writer. Many small
- apps work, but it is not quite complete yet.</li>
-
-<li>Support was added for software floating point routines.</li>
+<li>Duncan and Anton made significant progress chasing down a number of problems
+ with C++ Zero-Cost exception handling in llvm-gcc 4.0 and 4.2. It is now at
+ the point where it "just works" on linux/X86-32 and has partial support on
+ other targets.</li>
-<li>DWARF debug information generation has been improved. LLVM now passes
- most of the GDB testsuite on MacOS and debug info is more dense.</li>
+<li>Devang and Duncan fixed a huge number of bugs relating to bitfields, pragma
+ pack, and variable sized fields in structures.</li>
-<li>A new register scavenger has been implemented, which is useful for
- finding free registers after register allocation. This is useful when
- rewriting frame references on RISC targets, for example.</li>
+<li>Tanya implemented support for <tt>__attribute__((noinline))</tt> in
+ llvm-gcc, and added support for generic variable annotations which are
+ propagated into the LLVM IR, e.g.
+ "<tt>int X __attribute__((annotate("myproperty")));</tt>".</li>
-<li>Heuristics have been added to avoid coalescing vregs with very large live
- ranges to physregs.</li>
+<li>Sheng Zhou and Christopher Lamb implemented alias analysis support for
+"restrict" pointer arguments to functions.</li>
-<li>Support now exists for very simple (but still very useful)
- rematerialization the register allocator, enough to move
- instructions like "load immediate" and constant pool loads.</li>
-
-<li>Significantly improved 'switch' lowering, improving codegen for
- sparse switches that have dense subregions, and implemented support
- for the shift/and trick.</li>
-
-<li>The code generator now has more accurate and general hooks for
- describing addressing modes ("isLegalAddressingMode") to
- optimizations like loop strength reduction and code sinking.</li>
-
-<li>The Loop Strength Reduction pass has been improved, and support added
- for sinking expressions across blocks to reduce register pressure.</li>
-
-<li>Added support for tracking physreg sub-registers and super-registers
- in the code generator, as well as extensive register
- allocator changes to track them.</li>
-
-<li>There is initial support for virtreg sub-registers
- (<a href="http://llvm.org/PR1350">PR1350</a>).</li>
+<li>Duncan contributed support for trampolines (taking the address of a nested
+ function). Currently this is only supported on the X86-32 target.</li>
+<li>Lauro Ramos Venancio contributed support to encode alignment info in
+ load and store instructions, the foundation for other alignment-related
+ work.</li>
</ul>
+
+</div>
-<p>In addition, the LLVM target description format has itself been extended in
- several ways:</p>
-
-<ul>
-<li>Extended TargetData to support better target parameterization in
- the .ll/.bc files, eliminating the 'pointersize/endianness' attributes
- in the files (<a href="http://llvm.org/PR761">PR761</a>).</li>
-
-<li>TargetData was generalized for finer grained alignment handling,
- handling of vector alignment, and handling of preferred alignment</li>
-
-<li>LLVM now supports describing target calling conventions
- explicitly in .td files, reducing the amount of C++ code that needs
- to be written for a port.</li>
-
-</ul>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="coreimprovements">LLVM Core Improvements</a>
</div>
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="specifictargets">Target-Specific
-Improvements</a></div>
-
<div class="doc_text">
-
-<p>X86-Specific Code Generator Enhancements:
-</p>
-
-<ul>
-<li>The scheduler was improved to better reduce register pressure on
- X86 and other targets that are register pressure sensitive</li>
-<li>Linux/x86-64 support has been improved.</li>
-<li>PIC support for linux/x86 has been added.</li>
-<li>Support now exists for the GCC regparm attribute, and code in the X86
- backend to respect it.</li>
-<li>Various improvements have been made for the X86-64 JIT, allowing it to
- generate code in the large code model</li>
-<li>LLVM now supports inline asm with multiple constraint letters per operand
- (like "ri") which is common in X86 inline asms.</li>
-<li>Early support has been added for X86 inline asm in the C backend.</li>
-<li>Added support for the X86 MMX instruction set.</li>
-
-</ul>
-
-<p>ARM-Specific Code Generator Enhancements:
-</p>
-
-<ul>
-<li>Several improvements have been made to the ARM backend, including basic
- inline asm support, weak linkage support, static ctor/dtor support and
- many bug fixes.</li>
-<li>There are major enhancements to the ARM backend, including support for ARM
- v4-v6, vfp support, soft float, pre/postinc support, load/store multiple
- generation, constant pool entry motion (to support large functions),
- and enhancements to ARM constant island pass.
- </li>
-<li>Added support for Thumb code generation (an ARM subtarget).</li>
-<li>More aggressive size analysis for ARM inline asm strings was
- implemented.</li>
-</ul>
-
-<p>Other Target-Specific Code Generator Enhancements:
+<p>New features include:
</p>
<ul>
-<li>The PowerPC 64 JIT now supports addressing code loaded above the 2G
- boundary.</li>
-
-<li>Improved support for the Linux/ppc ABI and the linux/ppc JIT is fully
- functional now. llvm-gcc and static compilation are not fully supported
- yet though.</li>
-
-<li>Many bugs fixed for PowerPC 64.</li>
-
-<li>Support was added for the ARM AAPCS and EABI ABIs and PIC codegen on
- arm/linux.</li>
-
-<li>Several bugs in DWARF debug emission on linux and cygwin/mingw were fixed.
- Debugging basically works on these targets now.</li>
-
-<li>Support has been added for the X86-64 large code model to the JIT,
- which is useful if JIT'd function bodies are more than 2G away from
- library functions.</li>
+<li>Neil Booth contributed a new "APFloat" class, which ensures that floating
+ point representation and constant folding is not dependent on the host
+ architecture that builds the application. This support is the foundation
+ for "long double" support that will be wrapped up in LLVM 2.2.</li>
+
+<li>Based on the APFloat class, Dale redesigned the internals of the ConstantFP
+ class and has been working on extending the core and optimizer components to
+ support various target-specific 'long double's. We expect this work to be
+ completed in LLVM 2.2.</li>
-<li>Several bugs were fixed for DWARF debug info generation on arm/linux.</li>
+<li>LLVM now provides an LLVMBuilder class, which makes it significantly easier
+ to create LLVM IR instructions.</li>
+<li>Reid contributed support for intrinsics that take arbitrary integer typed
+ arguments. Dan Gohman and Chandler extended it to support arbitrary
+ floating point arguments and vectors.</li>
</ul>
-
+
</div>
-
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="other">Other Improvements</a></div>
-<div class="doc_text">
-
-<p>This release includes many other improvements, including
-performance work, specifically designed to tune datastructure
-usage. This makes several critical components faster.</p>
-
-<p>More specific changes include:</p>
-
-<ul>
-<li>LLVM no longer relies on static destructors to shut itself down. Instead,
- it lazily initializes itself and shuts down when llvm_shutdown() is
- explicitly called.</li>
-
-<li>LLVM now has significantly fewer static constructors, reducing startup time.
- </li>
-
-<li>Several classes have been refactored to reduce the amount of code that
- gets linked into apps that use the JIT.</li>
-
-<li>Construction of intrinsic function declarations has been simplified.</li>
-
-<li>The llvm-upgrade tool now exists. This migrates LLVM 1.9 .ll files to
- LLVM 2.0 syntax.</li>
-
-<li>The gccas/gccld tools have been removed.</li>
-
-<li>Support has been added to llvm-test for running on low-memory
- or slow machines (make SMALL_PROBLEM_SIZE=1).</li>
-
-<li>llvm-test is now more portable and should build with MS Visual Studio.</li>
-
-</ul>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="otherimprovements">Other Improvements</a>
</div>
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="apichanges">API Changes</a></div>
<div class="doc_text">
-
-<p>LLVM 2.0 contains a revamp of the type system and several other significant
-internal changes. If you are programming to the C++ API, be aware of the
-following major changes:</p>
+<p>New features include:
+</p>
<ul>
-<li>Pass registration is slightly different in LLVM 2.0 (you now needs an
- intptr_t in your constructor), as explained in the <a
- href="WritingAnLLVMPass.html#basiccode">Writing an LLVM Pass</a>
- document.</li>
-
-<li><tt>ConstantBool</tt>, <tt>ConstantIntegral</tt> and <tt>ConstantInt</tt>
- classes have been merged together, we now just have
- <tt>ConstantInt</tt>.</li>
-
-<li><tt>Type::IntTy</tt>, <tt>Type::UIntTy</tt>, <tt>Type::SByteTy</tt>, ... are
- replaced by <tt>Type::Int8Ty</tt>, <tt>Type::Int16Ty</tt>, etc. LLVM types
- have always corresponded to fixed size types
- (e.g. long was always 64-bits), but the type system no longer includes
- information about the sign of the type.</li>
-
-<li>Several classes (<tt>CallInst</tt>, <tt>GetElementPtrInst</tt>,
- <tt>ConstantArray</tt>, etc), that once took <tt>std::vector</tt> as
- arguments now take ranges instead. For example, you can create a
- <tt>GetElementPtrInst</tt> with code like:
-
- <pre>
- Value *Ops[] = { Op1, Op2, Op3 };
- GEP = new GetElementPtrInst(BasePtr, Ops, 3);
- </pre>
-
- This avoids creation of a temporary vector (and a call to malloc/free). If
- you have an std::vector, use code like this:
- <pre>
- std::vector<Value*> Ops = ...;
- GEP = new GetElementPtrInst(BasePtr, &Ops[0], Ops.size());
- </pre>
-
- </li>
-
-<li>CastInst is now abstract and its functionality is split into several parts,
- one for each of the <a href="LangRef.html#convertops">new cast
- instructions</a>.</li>
-
-<li><tt>Instruction::getNext()/getPrev()</tt> are now private (along with
- <tt>BasicBlock::getNext</tt>, etc), for efficiency reasons (they are now no
- longer just simple pointers). Please use BasicBlock::iterator, etc instead.
-</li>
+<li>Sterling Stein contributed a new BrainF frontend, located in llvm/examples.
+ This shows a some of the more modern APIs for building a front-end, and
+ demonstrates JIT compiler support.</li>
-<li><tt>Module::getNamedFunction()</tt> is now called
- <tt>Module::getFunction()</tt>.</li>
-
-<li><tt>SymbolTable.h</tt> has been split into <tt>ValueSymbolTable.h</tt> and
-<tt>TypeSymbolTable.h</tt>.</li>
+<li>David Green contributed a new <tt>--enable-expensive-checks</tt> configure
+ option which enables STL checking, and fixed several bugs exposed by
+ it.</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
+<li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
(and probably other unix-like systems).</li>
+<li>PowerPC and X86-based Mac OS X systems, running 10.2 and above in 32-bit and
+ 64-bit modes.</li>
<li>Intel and AMD machines running on Win32 using MinGW libraries (native)</li>
-<li>Sun UltraSPARC workstations running Solaris 8.</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>PowerPC and X86-based Mac OS X systems, running 10.2 and above in 32-bit and
- 64-bit modes.</li>
+<li>Sun UltraSPARC workstations running Solaris 8.</li>
<li>Alpha-based machines running Debian GNU/Linux.</li>
<li>Itanium-based machines running Linux and HP-UX.</li>
</ul>
components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
<ul>
-<li>The <tt>-cee</tt> pass is known to be buggy, and may be removed in in a
+<li>The <tt>-cee</tt> pass is known to be buggy, and may be removed in a
future release.</li>
-<li>C++ EH support</li>
+<li>The MSIL backend is experimental.</li>
<li>The IA64 code generator is experimental.</li>
-<li>The Alpha JIT is experimental.</li>
+<li>The Alpha backend is experimental.</li>
<li>"<tt>-filetype=asm</tt>" (the default) is the only supported value for the
<tt>-filetype</tt> llc option.</li>
</ul>
<ul>
<li>The X86 backend does not yet support <a href="http://llvm.org/PR879">inline
assembly that uses the X86 floating point stack</a>.</li>
+<li>The X86 backend occasionally has <a href="http://llvm.org/PR1649">alignment
+ problems</a> on operating systems that don't require 16-byte stack alignment
+ (including most non-darwin OS's like linux).</li>
</ul>
</div>
<li><a href="http://llvm.org/PR642">PowerPC backend does not correctly
implement ordered FP comparisons</a>.</li>
<li>The Linux PPC32/ABI support needs testing for the interpreter and static
-compilation, and lacks Dwarf debugging informations.
+compilation, and lacks support for debug information.</li>
</ul>
</div>
<div class="doc_text">
<ul>
-<li>The Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
-processors, any thumb program compiled with LLVM crashes or produces wrong
-results. (<a href="http://llvm.org/PR1388">PR1388</a>)</li>
+<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
+processors, thumb programs can crash or produce wrong
+results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
</li>
-<li>QEMU-ARM (<= 0.9.0) wrongly executes programs compiled with LLVM. A non-affected QEMU version must be used or this
-<a href="http://cvs.savannah.nongnu.org/viewcvs/qemu/target-arm/translate.c?root=qemu&r1=1.46&r2=1.47&makepatch=1&diff_format=h">
-patch</a> must be applied on QEMU.</li>
+<li>There is a bug in QEMU-ARM (<= 0.9.0) which causes it to incorrectly execute
+programs compiled with LLVM. Please use more recent versions of QEMU.</li>
</ul>
</div>
<ul>
<li><a href="http://llvm.org/PR802">The C backend does not support inline
assembly code</a>.</li>
+<li><a href="http://llvm.org/PR1126">The C backend does not support vectors
+ yet</a>.</li>
+<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
+ C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
+ C++ code compiled with LLC or native compilers.</li>
</ul>
</div>
See <a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</p>
</li>
-<li><p>llvm-gcc <b>partially</b> supports tthese GCC extensions:</p>
+<li><p>llvm-gcc <b>partially</b> supports these GCC extensions:</p>
<ol>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html#Nested%20Functions">Nested Functions</a>: As in Algol and Pascal, lexical scoping of functions.<br>
- Nested functions are supported, but llvm-gcc does not support non-local
- gotos or taking the address of a nested function.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html#Nested%20Functions">Nested Functions</a>:
+
+ As in Algol and Pascal, lexical scoping of functions.
+ Nested functions are supported, but llvm-gcc does not support
+ taking the address of a nested function (except on the X86-32 target)
+ or non-local gotos.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Declaring that functions have no side effects or that they can never
return.<br>
- <b>Supported:</b> <tt>alias</tt>, <tt>always_inline</tt>, <tt>cdecl</tt>,
- <tt>constructor</tt>, <tt>destructor</tt>,
+ <b>Supported:</b> <tt>alias</tt>, <tt>always_inline</tt>, <tt>cdecl</tt>,
+ <tt>const</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
<tt>deprecated</tt>, <tt>fastcall</tt>, <tt>format</tt>,
- <tt>format_arg</tt>, <tt>non_null</tt>, <tt>noreturn</tt>, <tt>regparm</tt>
+ <tt>format_arg</tt>, <tt>non_null</tt>, <tt>noinline</tt>,
+ <tt>noreturn</tt>, <tt>pure</tt>, <tt>regparm</tt>
<tt>section</tt>, <tt>stdcall</tt>, <tt>unused</tt>, <tt>used</tt>,
<tt>visibility</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
- <b>Ignored:</b> <tt>noinline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
- <tt>malloc</tt>, <tt>no_instrument_function</tt></li>
+ <b>Ignored:</b> <tt>nothrow</tt>, <tt>malloc</tt>,
+ <tt>no_instrument_function</tt></li>
</ol>
</li>
itself, Qt, Mozilla, etc.</p>
<ul>
-<li>llvm-gcc4 only has partial support for <a href="http://llvm.org/PR870">C++
-Exception Handling</a>, and it is not enabled by default.</li>
+<li>Exception handling only works well on the linux/X86-32 target.
+In some cases, illegally throwing an exception does not result
+in a call to terminate.</li>
<!-- NO EH Support!
<p>A wide variety of additional information is available on the <a
href="http://llvm.org">LLVM web page</a>, in particular in the <a
href="http://llvm.org/docs/">documentation</a> section. The web page also
-contains versions of the API documentation which is up-to-date with the CVS
-version of the source code.
+contains versions of the API documentation which is up-to-date with the
+Subversion version of the source code.
You can access versions of these documents specific to this release by going
into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
projects / oota-llvm.git / blobdiff