<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 2.2 Release Notes</title>
</head>
<body>
-<div class="doc_title">LLVM 2.0 Release Notes</div>
+<div class="doc_title">LLVM 2.2 Release Notes</div>
<ol>
<li><a href="#intro">Introduction</a></li>
<p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
</div>
+<h1><font color="red">THIS IS A WORK IN PROGRESS FOR THE LLVM 2.2
+RELEASE</font</h1>
+
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="intro">Introduction</a>
<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 2.2. 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 (described below).</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. Users are required to
- upgrade to llvm-gcc4. llvm-gcc4 includes many features over
- llvm-gcc3, is faster, and is <a href="CFEBuildInstrs.html">much easier to
- build from source</a>.</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. This is
- the first LLVM release to correctly compile and optimize major software like
- LLVM itself, Mozilla/Seamonkey, Qt 4.3rc1, kOffice, etc out of the box on
- linux/x86.
- </p>
+<p>This is the thirteenth public release of the LLVM Compiler Infrastructure.
+It includes many features and refinements from LLVM 2.1.</p>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="newfeatures">New Features in LLVM 2.0</a>
+<a name="frontends">llvm-gcc 4.0, llvm-gcc 4.2, and clang</a>
</div>
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="majorchanges">Major Changes</a></div>
<div class="doc_text">
-<p>Changes to the LLVM IR itself:</p>
-
-<ul>
-
-<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>). This
- eliminates cast instructions that just change the sign of the operands (e.g.
- int -> uint), which reduces the size of the IR and makes optimizers
- simpler to write.</li>
-
-<li>Integer types with arbitrary bitwidths (e.g. i13, i36, i42, i1057, etc) are
- now supported in the LLVM IR and optimizations (<a
- href="http://llvm.org/PR1043">PR1043</a>). However, neither llvm-gcc
- (<a href="http://llvm.org/PR1284">PR1284</a>) nor the native code generators
- (<a href="http://llvm.org/PR1270">PR1270</a>) support non-standard width
- integers yet.</li>
-
-<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'. The <a
- href="BitCodeFormat.html">Bitcode Format</a> 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>Load and store instructions now track the alignment of their pointer
- (<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 '<tt>#pragma
- packed</tt>') or to capture extra alignment information.</li>
-</ul>
-
-<p>Major new features:</p>
-
-<ul>
+<p>LLVM 2.2 fully supports both the llvm-gcc 4.0 and llvm-gcc 4.2 front-ends (in
+LLVM 2.1, llvm-gcc 4.2 was beta). Since LLVM 2.1, the llvm-gcc 4.2 front-end
+has made leaps and bounds and is now at least as good as 4.0 in virtually every
+area, and is better in several areas (for example, exception handling
+correctness). We strongly recommend that you migrate from llvm-gcc 4.0 to
+llvm-gcc 4.2 in this release cycle because <b>LLVM 2.2 is the last release
+that will support llvm-gcc 4.0</b>: LLVM 2.3 will only support the llvm-gcc
+4.2 front-end.</p>
-<li>A number of ELF features are now supported by LLVM, including 'visibility',
- extern weak linkage, Thread Local Storage (TLS) with the <tt>__thread</tt>
- keyword, and symbol aliases.
- Among other things, this means that many of the special options needed to
- configure llvm-gcc on linux are no longer needed, and special hacks to build
- large C++ libraries like Qt are not needed.</li>
-
-<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>
-
-</ul>
+<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 2.2 release. If you are interested in
+this project, please see the web site.</p>
</div>
-
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="llvmgccfeatures">llvm-gcc
-Improvements</a></div>
-<div class="doc_text">
-<p>New features include:
-</p>
-
-<ul>
-<li>Precompiled Headers (PCH) are now supported.</li>
-
-<li>"<tt>#pragma packed</tt>" is now supported, as are the various features
- described above (visibility, extern weak linkage, __thread, aliases,
- etc).</li>
-
-<li>Tracking function parameter/result attributes is now possible.</li>
-
-<li>Many internal 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, nested functions, and many other
- things. This is primarily to supports non-C GCC front-ends, like Ada.</li>
-
-<li>It is simpler to configure llvm-gcc for linux.</li>
-
-</ul>
-
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="majorfeatures">Major New Features</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 <a href="WritingAnLLVMPass.html">pass manager</a> has been entirely
- rewritten, making it significantly smaller, simpler, and more extensible.
- Support has been added to run FunctionPasses interlaced with
- CallGraphSCCPasses, and we now support loop transformations explicitly with
- LoopPass.</li>
-<li>The <tt>-scalarrepl</tt> pass can now promote unions containing FP values
- into a register, it can also handle unions of vectors of the same
- size.</li>
+<p>Dale contributed full support for long double on x86/x86-64 (where it is 80
+bits) and on Darwin PPC/PPC64 (where it is 128 bits).</p>
-<li>LLVM 2.0 includes a new loop rotation pass, which converts "for loops" into
- "do/while loops", where the condition is at the bottom of the loop.</li>
+<p>Ada, gfortran</p>
-<li>The Loop Strength Reduction pass has been improved, and support added
- for sinking expressions across blocks to reduce register pressure.</li>
-
-<li>ModulePasses may now use the result of FunctionPasses.</li>
+<p>
+debug improvements -O0
+EH.
-<li>The [Post]DominatorSet classes have been removed from LLVM and clients
- switched to use the far-more-efficient ETForest class instead.</li>
+Gordon: GC Revamp. docs/GarbageCollection.html
-<li>The ImmediateDominator class has also been removed, and clients have been
- switched to use DominatorTree instead.</li>
+Kaleidescope: docs/tutorial
-<li>The predicate simplifier pass has been improved, making it able to do
- simple value range propagation and eliminate more conditionals.</li>
+Gordon: C and Ocaml Bindings
-</ul>
-
</div>
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="codegen">Code
-Generator Enhancements</a></div>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="optimizer">Optimizer Improvements</a>
+</div>
<div class="doc_text">
-<p>
-New features include:
-</p>
-
-<ul>
-<li>Support was added for software floating point, which allows LLVM to target
- chips that don't have hardware FPUs (e.g. ARM thumb mode).</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>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>
+<ul>
-<li>Heuristics have been added to avoid coalescing vregs with very large live
- ranges to physregs. This was bad because it effectively pinned the physical
- register for the entire lifetime of the virtual register (<a
- href="http://llvm.org/PR711">PR711</a>).</li>
+<li>Daniel Berlin and (Curtis?) rewrote Andersen's alias analysis (which is not
+enabled by default) to be several orders of magnitude faster, implmented Offline
+Variable Substitution.</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>Switch statement lowering is significantly better, improving codegen for
- sparse switches that have dense subregions, and implemented support
- for the shift/and trick.</li>
+Devang: LoopIndexSplit is enabled by default.
+</ul>
-<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>
+</div>
-<li>There is initial support for virtreg sub-registers
- (<a href="http://llvm.org/PR1350">PR1350</a>).</li>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="codegen">Code Generator Improvements</a>
+</div>
-</ul>
+<div class="doc_text">
-<p>
-Other improvements include:
-</p>
+<p>foci of this release was performance tuning and bug
+ fixing. In addition to these, several new major changes occurred:</p>
<ul>
-<li>Inline assembly support is much more solid that before.
- The two primary features still missing 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>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>Codegen support for Zero-cost DWARF exception handling has been added (<a
- href="http://llvm.org/PR592">PR592</a>). It is mostly
- complete and just in need of continued bug fixes and optimizations at
- this point. However, support in llvm-g++ is disabled with an
- #ifdef for the 2.0 release (<a
- href="http://llvm.org/PR870">PR870</a>).</li>
+<li>Owen contributed Machine Loop info, domintors, etc. Merged dom and
+ postdom.</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>Dan added support for emitting debug information with .file and .loc on
+targets that support it</li>
-<li>Progress has been made on a direct Mach-o .o file writer. Many small
- apps work, but it is still not quite complete.</li>
+<li>Evan physical register dependencies in the BURR scheduler</li>
+<li>Evan EXTRACT_SUBREG coalescing support</li>
</ul>
-<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>
+</div>
-</ul>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="targetspecific">Target Specific 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>New features include:
</p>
<ul>
-<li>The MMX instruction set is now supported through intrinsics.</li>
-<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 is much better.</li>
-<li>PIC support for linux/x86 has been added.</li>
-<li>The X86 backend now supports the GCC regparm attribute.</li>
-<li>LLVM now supports inline asm with multiple constraint letters per operand
- (like "ri") which is common in X86 inline asms.</li>
+<li>Evan X86 now models EFLAGS in instructions.</li>
+<li>Evan: If conversion on by default for ARM.</li>
+<li>Bruno: MIPS PIC support.</li>
+<li>Arnold Schwaighofer: X86 tail call support.</li>
</ul>
+
+</div>
-<p>ARM-specific Code Generator Enhancements:</p>
-
-<ul>
-<li>The ARM code generator is now stable and fully supported.</li>
-
-<li>There are major new features, including support for ARM
- v4-v6 chips, vfp support, soft float point support, pre/postinc support,
- load/store multiple generation, constant pool entry motion (to support
- large functions), and inline asm support, weak linkage support, static
- ctor/dtor support and many bug fixes.</li>
-<li>Added support for Thumb code generation (<tt>llc -march=thumb</tt>).</li>
-
-<li>The ARM backend now supports the ARM AAPCS/EABI ABI and PIC codegen on
- arm/linux.</li>
-<li>Several bugs were fixed for DWARF debug info generation on arm/linux.</li>
-</ul>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="llvmgccimprovements">llvm-gcc Improvements</a>
+</div>
-<p>PowerPC-specific Code Generator Enhancements:</p>
+<div class="doc_text">
+<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 PowerPC 64 bug fixes.</li>
-
+<li>.</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>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="coreimprovements">LLVM Core Improvements</a>
+</div>
-<p>More specific changes include:</p>
+<div class="doc_text">
+<p>New features 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>
-
+<li>Devang added LLVMFoldingBuilder.</li>
+<li>Dan added support for vector sin, cos, and pow intrinsics.</li>
</ul>
+
</div>
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="apichanges">API Changes</a></div>
-<div class="doc_text">
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="otherimprovements">Other Improvements</a>
+</div>
-<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>
+<div class="doc_text">
+<p>New features include:
+</p>
<ul>
-<li>Pass registration is slightly different in LLVM 2.0 (you now need 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><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>.</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>Intel and AMD machines running on Win32 using MinGW libraries (native)</li>
-<li>Sun UltraSPARC workstations running Solaris 8.</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>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
- future release.</li>
-<li>C++ EH support</li>
-<li>The IA64 code generator is experimental.</li>
-<li>The Alpha JIT is experimental.</li>
-<li>"<tt>-filetype=asm</tt>" (the default) is the only supported value for the
- <tt>-filetype</tt> llc option.</li>
+<li>The <tt>-cee</tt> pass is known to be buggy and will be removed in
+ LLVM 2.3.</li>
+<li>The MSIL, IA64, Alpha, 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 llvmc tool is not supported.</li>
</ul>
</div>
<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>
<div class="doc_text">
<ul>
-<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>
<div class="doc_text">
-<p>llvm-gcc4 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
+<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>
</div>
<div class="doc_text">
<ul>
-<li><p>"long double" is silently transformed by the front-end into "double". There
-is no support for floating point data types of any size other than 32 and 64
-bits.</p></li>
-
<li><p>llvm-gcc does <b>not</b> support <tt>__builtin_apply</tt> yet.
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>
-
-<!-- NO EH Support!
-
-<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
- performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
- function and in the <tt>setjmp</tt> receiver function may not be run.
- Objects in intervening stack frames will be destroyed, however (which is
- better than most compilers).</li>
-
-<li>The LLVM C++ front-end follows the <a
- href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
- This document, which is not Itanium specific, specifies a standard for name
- mangling, class layout, v-table layout, RTTI formats, and other C++
- representation issues. Because we use this API, code generated by the LLVM
- compilers should be binary compatible with machine code generated by other
- Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
- <i>However</i>, the exception handling mechanism used by llvm-gcc3 is very
- different from the model used in the Itanium ABI, so <b>exceptions will not
- interact correctly</b>. </li>
--->
+<li>Exception handling only works well on the X86 and PowerPC targets.</li>
</ul>
</div>
<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