<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link rel="stylesheet" href="llvm.css" type="text/css">
- <title>LLVM 1.5 Release Notes</title>
+ <title>LLVM 2.2 Release Notes</title>
</head>
<body>
-<div class="doc_title">LLVM 1.5 Release Notes</div>
+<div class="doc_title">LLVM 2.2 Release Notes</div>
<ol>
<li><a href="#intro">Introduction</a></li>
</ol>
<div class="doc_author">
- <p>Written by the <a href="http://llvm.
cs.uiuc.edu">LLVM Team</a><p>
+ <p>Written by the <a href="http://llvm.
org">LLVM Team</a><p>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<p>This document contains the release notes for the LLVM compiler
-infrastructure, release 1.5. Here we describe the status of LLVM, including any
-known problems and major improvements from the previous release. The most
-up-to-date version of this document can be found on the <a
-href="http://llvm.cs.uiuc.edu/releases/1.5/">LLVM 1.5 web site</a>. If you are
-not reading this on the LLVM web pages, you should probably go there because
-this document may be updated after the release.</p>
+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>.</p>
<p>For more information about LLVM, including information about the latest
-release, please check out the <a href="http://llvm.cs.uiuc.edu">main LLVM
+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>
-<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.cs.uiuc.edu/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 sixth public release of the LLVM Compiler Infrastructure.</p>
-
-<p>LLVM 1.5 is known to correctly compile a wide range of C and C++ programs,
-includes bug fixes for those problems found since the 1.4 release, and includes
-a large number of new features and enhancements, described below.</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 1.5</a>
+<a name="frontends">llvm-gcc 4.0, llvm-gcc 4.2, and clang</a>
</div>
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="newcg">New Native Code
-Generators</a></div>
-
<div class="doc_text">
-<p>
-This release includes new native code generators for <a
-href="#alpha-be">Alpha</a>, <a href="#ia64-be">IA-64</a>, and <a
-href="#sparcv8">SPARC-V8</a> (32-bit SPARC). These code generators are still
-beta quality, but are progressing rapidly. The Alpha backend is implemented
-with an eye towards being compatible with the widely used SimpleScalar
-simulator.
-</p>
-</div>
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="selectiondag">New Instruction
-Selector Framework</a></div>
+<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>
+
+<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 class="doc_text">
-<p>This release includes a <a href="CodeGenerator.html#instselect">new framework
-for building instruction selectors</a>, which has long been the hardest part of
-building a new LLVM target. This framework handles a lot of the mundane (but
-easy to get wrong) details of writing the instruction selector, such as
-generating efficient code for <a
-href="LangRef.html#i_getelementptr">getelementptr</a> instructions, promoting
-small integer types to larger types (e.g. for RISC targets with one size of
-integer registers), expanding 64-bit integer operations for 32-bit targets, etc.
-Currently, the X86, PowerPC, Alpha, and IA-64 backends use this framework. The
-SPARC backends will be migrated when time permits.
-</p>
</div>
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="customccs">New Support for Per-Function
-Calling Conventions</a></div>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="majorfeatures">Major New Features</a>
+</div>
<div class="doc_text">
-<p>LLVM 1.5 adds supports for <a href="LangRef.html#callingconv">per-function
-calling conventions</a>. Traditionally, the LLVM code generators match the
-native C calling conventions for a target. This is important for compatibility,
-but is not very flexible. This release allows custom calling conventions to be
-established for functions, and defines three target-independent conventions (<a
-href="LangRef.html#callingconv">C call, fast call, and cold call</a>) which may
-be supported by code generators. When possible, the LLVM optimizer promotes C
-functions to use the "fastcc" convention, allowing the use of more efficient
-calling sequences (e.g., parameters are passed in registers in the X86 target).
-</p>
-<p>Targets may now also define target-specific calling conventions, allowing
-LLVM to fully support calling convention altering options (e.g. GCC's
-<tt>-mregparm</tt> flag) and well-defined target conventions (e.g. stdcall and
-fastcall on X86).</p>
-</div>
+<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>
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection"><a name="tailcalls">New Support for
-Proper Tail Calls</a></div>
+<p>Ada, gfortran</p>
-<div class="doc_text">
-<p>The release now includes support for <a
-href="http://doi.acm.org/10.1145/277650.277719">proper tail calls</a>, as
-required to implement languages like Scheme. Tail calls make use of two
-features: custom calling conventions (described above), which allow the code
-generator to use a convention where the caller deallocates its stack before it
-returns. The second feature is a flag on the <a href="LangRef.html#i_call">call
-instruction</a>, which indicates that the callee does not access the caller's
-stack frame (indicating that it is acceptable to deallocate the caller stack
-before invoking the callee). LLVM proper tail calls run on the system stack (as
-do normal calls), supports indirect tail calls, tail calls with arbitrary
-numbers of arguments, tail calls where the callee requires more argument space
-than the caller, etc. The only case not supported are varargs calls, but that
-could be added if desired.
-</p>
+<p>
+debug improvements -O0
+EH.
-<p>In order for a front-end to get a guaranteed tail call, it must mark
-functions as "fastcc", mark calls with the 'tail' marker, and follow the call
-with a return of the called value (or void). The optimizer and code generator
-attempt to handle more general cases, but the simple case will always work if
-the code generator supports tail calls. Here is an example:</p>
-
-<pre>
- fastcc int %bar(int %X, int(double, int)* %FP) { ;<i> fastcc</i>
- %Y = tail call fastcc int %FP(double 0.0, int %X) ;<i> tail, fastcc</i>
- ret int %Y
- }
-</pre>
-
-<p>In LLVM 1.5, the X86 code generator is the only target that has been enhanced
-to support proper tail calls (other targets will be enhanced in future).
-Further, because this support was added very close to the release, it is
-disabled by default. Pass <tt>-enable-x86-fastcc</tt> to llc to enable it (this
-will be enabled by default in the next release). The example above compiles to:
-</p>
+Gordon: GC Revamp. docs/GarbageCollection.html
-<pre>
- bar:
- sub ESP, 8 # Callee uses more space than the caller
- mov ECX, DWORD PTR [ESP + 8] # Get the old return address
- mov DWORD PTR [ESP + 4], 0 # First half of 0.0
- mov DWORD PTR [ESP + 8], 0 # Second half of 0.0
- mov DWORD PTR [ESP], ECX # Put the return address where it belongs
- jmp EDX # Tail call "FP"
-</pre>
+Kaleidescope: docs/tutorial
-<p>
-With fastcc on X86, the first two integer arguments are passed in EAX/EDX, the
-callee pops its arguments off the stack, and the argument area is always a
-multiple of 8 bytes in size.
-</p>
+Gordon: C and Ocaml Bindings
</div>
-<!--_________________________________________________________________________-->
-<div class="doc_subsubsection">Other New Features</div>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="optimizer">Optimizer Improvements</a>
+</div>
<div class="doc_text">
-<ol>
- <li>LLVM now includes an <a href="http://llvm.cs.uiuc.edu/PR415">
- Interprocedural Sparse Conditional Constant Propagation</a> pass, named
- -ipsccp, which is run by default at link-time.</li>
- <li>LLVM 1.5 is now about 15% faster than LLVM 1.4 and its core data
- structures use about 30% less memory.</li>
- <li>Support for Microsoft Visual Studio is improved, and <a
- href="GettingStartedVS.html">now documented</a>. Most LLVM tools build
- natively with Visual C++ now.</li>
- <li><a href="GettingStarted.html#config">Configuring LLVM to build a subset
- of the available targets</a> is now implemented, via the
- <tt>--enable-targets=</tt> option.</li>
- <li>LLVM can now create native shared libraries with '<tt>llvm-gcc ...
- -shared -Wl,-native</tt>' (or with <tt>-Wl,-native-cbe</tt>).</li>
- <li>LLVM now supports a new "<a href="LangRef.html#i_prefetch">llvm.prefetch
- </a>" intrinsic, and llvm-gcc now supports __builtin_prefetch.
- <li>LLVM now supports intrinsics for <a href="LangRef.html#int_count">bit
- counting</a> and llvm-gcc now implements the GCC
- <tt>__builtin_popcount</tt>, <tt>__builtin_ctz</tt>, and
- <tt>__builtin_clz</tt> builtins.</li>
- <li>LLVM now mostly builds on HP-UX with the HP aCC Compiler.</li>
- <li>The LLVM X86 backend can now emit Cygwin-compatible .s files.</li>
- <li>LLVM now includes workarounds in the code generator generator which
- reduces the likelyhood of <a href="http://llvm.cs.uiuc.edu/PR448">GCC
- hitting swap during optimized builds</a>.</li>
- <li>The <a href="http://llvm.cs.uiuc.edu/ProjectsWithLLVM/#llvmtv">LLVM
- Transformation Visualizer</a> (llvm-tv) project has been updated to
- work with LLVM CVS.</li>
- <li>Nightly tester output is now archived on the <a
- href="http://mail.cs.uiuc.edu/pipermail/llvm-testresults/">
- llvm-testresults</a> mailing list.</li>
-</ol>
+<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>
+
+<ul>
+
+<li>Daniel Berlin and (?) rewrote Andersen's alias analysis (which is not
+enabled by default) to be several orders of magnitude faster, implmented Offline
+Variable Substitution.</li>
+
+
+Devang: LoopIndexSplit is enabled by default.
+</ul>
+
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="codequality">Code Quality Improvements in LLVM 1.5</a>
+<a name="codegen">Code Generator Improvements</a>
</div>
<div class="doc_text">
-<ol>
-<li>The new -simplify-libcalls pass improves code generated for well-known
-library calls. The pass optimizes calls to many of the string, memory, and
-standard I/O functions (e.g. replace the calls with simpler/faster calls) when
-possible, given information known statically about the arguments to the call.
-</li>
-<li>The -globalopt pass now promotes non-address-taken static globals that are
-only accessed in main to SSA registers.</li>
+<p>foci of this release was performance tuning and bug
+ fixing. In addition to these, several new major changes occurred:</p>
-<li>Loops with trip counts based on array pointer comparisons (e.g. "<tt>for (i
-= 0; &A[i] != &A[n]; ++i) ...</tt>") are optimized better than before,
-which primarily helps iterator-intensive C++ codes.</li>
+<ul>
-<li>The optimizer now eliminates simple cases where redundant conditions exist
- between neighboring blocks.</li>
+<li>Owen contributed Machine Loop info, domintors, etc.</li>
-<li>The reassociation pass (which turns (1+X+3) into (X+1+3) among other
-things), is more aggressive and intelligent.</li>
+<li>Dan added support for emitting debug information with .file and .loc on
+targets that support it</li>
-<li>The -prune-eh pass now detects no-return functions in addition to the
- no-unwind functions it did before.</li>
+<li>Evan physical register dependencies in the BURR scheduler</li>
+</ul>
-<li>The -globalsmodref alias analysis generates more precise results in some
- cases.</li>
-</ol>
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="codequality">Code Generator Improvements in LLVM 1.5</a>
+<a name="targetspecific">Target Specific Improvements</a>
</div>
<div class="doc_text">
-<ol>
-<li>The code generator now can provide and use information about commutative
- two-address instructions when performing register allocation.</li>
+<p>New features include:
+</p>
+
+<ul>
+<li>Evan X86 now models EFLAGS in instructions.</li>
+<li>Evan: If conversion on by default for ARM.</li>
+</ul>
+
+</div>
-<li>The code generator now tracks function live-in registers explicitly,
- instead of requiring the target to generate 'implicit defs' at the
- entry to a function.</li>
-<li>The code generator can lower integer division by a constant to
- multiplication by a magic constant and multiplication by a constant into
- shift/add sequences.</li>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="llvmgccimprovements">llvm-gcc Improvements</a>
+</div>
-<li>The code generator compiles fabs/fneg/sin/cos/sqrt to assembly instructions
- when possible.</li>
+<div class="doc_text">
+<p>New features include:
+</p>
-<li>The PowerPC backend generates better code in many cases, making use of
- FMA instructions and the recording ("dot") forms of various PowerPC
- instructions.</li>
-</ol>
+<ul>
+<li>.</li>
+</ul>
+
</div>
<!--=========================================================================-->
<div class="doc_subsection">
-<a name="bugfix">Significant Bugs Fixed in LLVM 1.5</a>
+<a name="coreimprovements">LLVM Core Improvements</a>
</div>
<div class="doc_text">
+<p>New features include:
+</p>
+<ul>
+<li>.</li>
+</ul>
+
+</div>
-<p>Bugs fixed in the LLVM Core:</p>
-<ol>
- <li><a href="http://llvm.cs.uiuc.edu/PR491">[dse] DSE deletes stores that
- are partially overwritten by smaller stores</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR548">[instcombine] miscompilation of
- setcc or setcc in one case</a></li>
- <li>Transition code for LLVM 1.0 style varargs was removed from the .ll file
- parser. LLVM 1.0 bytecode files are still supported. </li>
-</ol>
-
-<p>Code Generator Bugs:</p>
-<ol>
- <li><a href="http://llvm.cs.uiuc.edu/PR490">[cbackend] Logical constant
- expressions (and/or/xor) not implemented</a>.</li>
- <li><a href="http://llvm.cs.uiuc.edu/PR511">[cbackend] C backend does not
- respect 'volatile'</a>.</li>
- <li>The JIT sometimes miscompiled globals and constant pool entries for
- 64-bit integer constants on 32-bit hosts.</li>
- <li>The C backend should no longer produce code that crashes ICC 8.1.</li>
-</ol>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="otherimprovements">Other Improvements</a>
+</div>
-<p>Bugs in the C/C++ front-end:</p>
-<ol>
- <li><a href="http://llvm.cs.uiuc.edu/PR487">[llvmgcc] llvm-gcc incorrectly
- rejects some constant initializers involving the addresses of array
- elements</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR501">[llvm-g++] Crash compiling
- anonymous union</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR509">[llvm-g++] Do not use dynamic
- initialization where static init will do</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR510">[llvmgcc] Field offset
- miscalculated for some structure fields following bit fields</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR513">[llvm-g++] Temporary lifetimes
- incorrect for short circuit logical operations</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR517">[llvm-gcc] Crash compiling
- bitfield <-> aggregate assignment</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR520">[llvm-g++] Error compiling
- virtual function thunk with an unnamed argument</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR522">[llvm-gcc] Crash on certain
- C99 complex number routines</a></li>
- <li><a href="http://llvm.cs.uiuc.edu/PR529">[llvm-g++] Crash using placement
- new on an array type</a></li>
-</ol>
+<div class="doc_text">
+<p>New features include:
+</p>
+<ul>
+<li>.</li>
+</ul>
+
</div>
<!-- *********************************************************************** -->
<p>LLVM is known to work on the following platforms:</p>
<ul>
-<li>Intel and AMD machines running Red Hat Linux and FreeBSD (and probably
- other unix-like systems).</li>
-<li>Sun UltraSPARC workstations running Solaris 8.</li>
+<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 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-based Mac OS X systems, running 10.2 and above.</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>
<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
-href="http://llvm.cs.uiuc.edu/bugs/">LLVM bug database</a> and submit a bug if
+href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
there isn't already one.</p>
</div>
be broken or unreliable, or are in early development. These components should
not be relied on, and bugs should not be filed against them, but they may be
useful to some people. In particular, if you would like to work on one of these
-components, please contact us on the llvmdev list.</p>
+components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
<ul>
-<li>The following passes are incomplete or buggy, and may be removed in future
- releases: <tt>-cee, -branch-combine, -instloops, -paths, -pre</tt></li>
-<li>The <tt>llvm-db</tt> tool is in a very early stage of development, but can
- be used to step through programs and inspect the stack.</li>
-<li>The "iterative scan" register allocator (enabled with
- <tt>-regalloc=iterativescan</tt>) is not stable.</li>
-<li>The SparcV8, Alpha, and IA64 code generators are experimental.</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>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="core">Known problems with the LLVM Core</a>
+ <a name="x86-be">Known problems with the X86 back-end</a>
</div>
<div class="doc_text">
<ul>
- <li>In the JIT, <tt>dlsym()</tt> on a symbol compiled by the JIT will not
- work.</li>
- <li>The JIT does not use mutexes to protect its internal data structures. As
- such, execution of a threaded program could cause these data structures to be
- corrupted.
- </li>
- <li><a href="http://llvm.cs.uiuc.edu/PR240">The lower-invoke pass does not
- mark values live across a setjmp as volatile</a>. This missing feature
- only affects targets whose setjmp/longjmp libraries do not save and restore
- the entire register file.</li>
+<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_subsection">
- <a name="c-fe">Known problems with the C front-end</a>
+ <a name="ppc-be">Known problems with the PowerPC back-end</a>
</div>
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">Bugs</div>
-
<div class="doc_text">
-<ul>
-<li>C99 Variable sized arrays do not release stack memory when they go out of
- scope. Thus, the following program may run out of stack space:
-<pre>
- for (i = 0; i != 1000000; ++i) {
- int X[n];
- foo(X);
- }
-</pre></li>
-
-<li>Initialization of global union variables can only be done <a
-href="http://llvm.cs.uiuc.edu/PR162">with the largest union member</a>.</li>
+<ul>
+<li>The Linux PPC32/ABI support needs testing for the interpreter and static
+compilation, and lacks support for debug information.</li>
</ul>
+
</div>
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- Notes
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="arm-be">Known problems with the ARM back-end</a>
</div>
<div class="doc_text">
<ul>
-
-<li>Inline assembly is not yet supported.</li>
-
-<li>"long double" is 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.</li>
-
-<li>The following Unix system functionality has not been tested and may not
-work:
- <ol>
- <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
- appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
- <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
- <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
- - These functions have not been tested.
- </ol></li>
-
-<li>Although many GCC extensions are supported, some are not. In particular,
- the following extensions are known to <b>not be</b> supported:
- <ol>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</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.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Extended%20Asm">Extended Asm</a>: Assembler instructions with C expressions as operands.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Asm-Labels.html#Asm%20Labels">Asm Labels</a>: Specifying the assembler name to use for a C symbol.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Explicit-Reg-Vars.html#Explicit%20Reg%20Vars">Explicit Reg Vars</a>: Defining variables residing in specified registers.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
- </ol>
-
- <p>The following GCC extensions are <b>partially</b> supported. An ignored
- attribute means that the LLVM compiler ignores the presence of the attribute,
- but the code should still work. An unsupported attribute is one which is
- ignored by the LLVM compiler and will cause a different interpretation of
- the program.</p>
-
- <ol>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
- Arrays whose length is computed at run time.<br>
- Supported, but allocated stack space is not freed until the function returns (noted above).</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>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
- <tt>noreturn</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
- <tt>unused</tt>,
- <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
-
- <b>Ignored:</b> <tt>noinline</tt>,
- <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
- <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
-
- <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>,
- <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
- <tt>fastcall</tt>, all other target specific attributes</li>
-
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
- Specifying attributes of variables.<br>
- <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
- <tt>deprecated</tt>, <tt>transparent_union</tt>,
- <tt>unused</tt>, <tt>weak</tt><br>
-
- <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
- <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
- <tt>vector_size</tt>, <tt>dllimport</tt>,
- <tt>dllexport</tt>, all target specific attributes.</li>
-
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.<br>
- <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
- <tt>deprecated</tt>, <tt>may_alias</tt><br>
-
- <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
- all target specific attributes.</li>
-
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
- Other built-in functions.<br>
- We support all builtins which have a C language equivalent (e.g.,
- <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
- <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
- <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
- (currently ignored). We also support builtins for ISO C99 floating
- point comparison macros (e.g., <tt>__builtin_islessequal</tt>),
- <tt>__builtin_prefetch</tt>, <tt>__builtin_popcount[ll]</tt>,
- <tt>__builtin_clz[ll]</tt>, and <tt>__builtin_ctz[ll]</tt>.</li>
- </ol>
-
- <p>The following extensions <b>are</b> known to be supported:</p>
-
- <ol>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Labels-as-Values.html#Labels%20as%20Values">Labels as Values</a>: Getting pointers to labels and computed gotos.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Typeof.html#Typeof">Typeof</a>: <code>typeof</code>: referring to the type of an expression.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc-3.4.0/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variadic-Macros.html#Variadic%20Macros">Variadic Macros</a>: Macros with a variable number of arguments.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Subscripting.html#Subscripting">Subscripting</a>: Any array can be subscripted, even if not an lvalue.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pointer-Arith.html#Pointer%20Arith">Pointer Arith</a>: Arithmetic on <code>void</code>-pointers and function pointers.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
-or arrays as values.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Cast-to-Union.html#Cast%20to%20Union">Cast to Union</a>: Casting to union type from any member of the union.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Comments.html#C_002b_002b-Comments">C++ Comments</a>: C++ comments are recognized.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Character-Escapes.html#Character%20Escapes">Character Escapes</a>: <code>\e</code> stands for the character <ESC>.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alternate-Keywords.html#Alternate%20Keywords">Alternate Keywords</a>:<code>__const__</code>, <code>__asm__</code>, etc., for header files.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Incomplete-Enums.html#Incomplete%20Enums">Incomplete Enums</a>: <code>enum foo;</code>, with details to follow.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Names.html#Function%20Names">Function Names</a>: Printable strings which are the name of the current function.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Return-Address.html#Return%20Address">Return Address</a>: Getting the return or frame address of a function.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html#Unnamed%20Fields">Unnamed Fields</a>: Unnamed struct/union fields within structs/unions.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.</li>
- </ol></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>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>
-<p>If you run into GCC extensions which have not been included in any of these
-lists, please let us know (also including whether or not they work).</p>
-
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="c++-fe">Known problems with the C++ front-end</a>
-</div>
-
-<div class="doc_text">
-
-<p>For this release, the C++ front-end is considered to be fully
-tested and works for a number of non-trivial programs, including LLVM
-itself.</p>
-
+ <a name="sparc-be">Known problems with the SPARC back-end</a>
</div>
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">Bugs</div>
-
<div class="doc_text">
<ul>
-<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
- front-end</a>.</li>
-
+<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>
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- Notes
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="alpha-be">Known problems with the Alpha back-end</a>
</div>
<div class="doc_text">
<ul>
-<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
-parser is significantly more standards compliant (and picky) than prior GCC
-versions. For more information, see the C++ section of the <a
-href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.</li>
-
-<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 is very
- different from the model used in the Itanium ABI, so <b>exceptions will not
- interact correctly</b>. </li>
+<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
+appropriate nops inserted to ensure restartability.</li>
</ul>
-
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="c-be">Known problems with the C back-end</a>
+ <a name="ia64-be">Known problems with the IA64 back-end</a>
</div>
<div class="doc_text">
<ul>
-<li>The C back-end produces code that violates the ANSI C Type-Based Alias
-Analysis rules. As such, special options may be necessary to compile the code
-(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
-problem probably cannot be fixed.</li>
-
-<li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
-supported</a>. This should not affect LLVM produced by the C or C++
-frontends.</li>
-
-</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>
-</div>
+<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>
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="x86-be">Known problems with the X86 back-end</a>
-</div>
+<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>
-<div class="doc_text">
+<li>Defining vararg functions is not supported (but calling them is ok).</li>
-<ul>
- <li>None yet</li>
+<li>The Itanium backend has bitrotted somewhat.</li>
</ul>
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="ppc-be">Known problems with the PowerPC back-end</a>
+ <a name="c-be">Known problems with the C back-end</a>
</div>
<div class="doc_text">
<ul>
-<li>None yet</li>
+<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_subsection">
- <a name="sparcv9-be">Known problems with the SparcV9 back-end</a>
+ <a name="c-fe">Known problems with the C front-end</a>
</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">Bugs</div>
+
<div class="doc_text">
-<ul>
-<li><a href="http://llvm.cs.uiuc.edu/PR60">[sparcv9] SparcV9 backend miscompiles
-several programs in the LLVM test suite</a></li>
-</ul>
+<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_subsection">
- <a name="alpha-be">Known problems with the Alpha back-end</a>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ Notes
</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>Defining vararg functions is not supported (but calling them is ok).</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>Due to the vararg problems, C++ exceptions do not work. Small changes are required to the CFE (which break correctness in the exception handler) to compile the exception handling library (and thus the C++ standard library).</li>
+<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>:
-</ul>
+ 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>
-</div>
-
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="ia64-be">Known problems with the IA64 back-end</a>
-</div>
-
-<div class="doc_text">
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
-<ul>
+ Declaring that functions have no side effects or that they can never
+ return.<br>
-<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>
+ <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>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>
-<li>The C++ front-end does not use <a href="http://llvm.cs.uiuc.edu/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>
+ <b>Ignored:</b> <tt>nothrow</tt>, <tt>malloc</tt>,
+ <tt>no_instrument_function</tt></li>
+ </ol>
+</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><p>llvm-gcc supports the vast majority of GCC extensions, including:</p>
-<li>Defining vararg functions is not supported (but calling them is ok).</li>
+ <ol>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
+ Other built-in functions.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
+ Specifying attributes of variables.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
+ Arrays whose length is computed at run time.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Labels-as-Values.html#Labels%20as%20Values">Labels as Values</a>: Getting pointers to labels and computed gotos.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Typeof.html#Typeof">Typeof</a>: <code>typeof</code>: referring to the type of an expression.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc-3.4.0/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variadic-Macros.html#Variadic%20Macros">Variadic Macros</a>: Macros with a variable number of arguments.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Extended%20Asm">Extended Asm</a>: Assembler instructions with C expressions as operands.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Asm-Labels.html#Asm%20Labels">Asm Labels</a>: Specifying the assembler name to use for a C symbol.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Explicit-Reg-Vars.html#Explicit%20Reg%20Vars">Explicit Reg Vars</a>: Defining variables residing in specified registers.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Subscripting.html#Subscripting">Subscripting</a>: Any array can be subscripted, even if not an lvalue.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pointer-Arith.html#Pointer%20Arith">Pointer Arith</a>: Arithmetic on <code>void</code>-pointers and function pointers.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
+or arrays as values.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Cast-to-Union.html#Cast%20to%20Union">Cast to Union</a>: Casting to union type from any member of the union.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Comments.html#C_002b_002b-Comments">C++ Comments</a>: C++ comments are recognized.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Character-Escapes.html#Character%20Escapes">Character Escapes</a>: <code>\e</code> stands for the character <ESC>.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alternate-Keywords.html#Alternate%20Keywords">Alternate Keywords</a>:<code>__const__</code>, <code>__asm__</code>, etc., for header files.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Incomplete-Enums.html#Incomplete%20Enums">Incomplete Enums</a>: <code>enum foo;</code>, with details to follow.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Names.html#Function%20Names">Function Names</a>: Printable strings which are the name of the current function.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Return-Address.html#Return%20Address">Return Address</a>: Getting the return or frame address of a function.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html#Unnamed%20Fields">Unnamed Fields</a>: Unnamed struct/union fields within structs/unions.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.</li>
+ </ol></li>
</ul>
+<p>If you run into GCC extensions which have not been included in any of these
+lists, please let us know (also including whether or not they work).</p>
+
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="sparcv8">Known problems with the SPARC-V8 back-end</a>
+ <a name="c++-fe">Known problems with the C++ front-end</a>
</div>
<div class="doc_text">
-<ul>
-<li>Many features are still missing (e.g. support for 64-bit integer
-arithmetic).</li>
+<p>The C++ front-end is considered to be fully
+tested and works for a number of non-trivial programs, including LLVM
+itself, Qt, Mozilla, etc.</p>
-<li>This backend needs to be updated to use the SelectionDAG instruction
-selection framework.</li>
+<ul>
+<li>Exception handling only works well on the X86 and PowerPC targets.</li>
</ul>
</div>
+
+
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="additionalinfo">Additional Information</a>
<div class="doc_text">
<p>A wide variety of additional information is available on the <a
-href="http://llvm.cs.uiuc.edu">LLVM web page</a>, including <a
-href="http://llvm.cs.uiuc.edu/docs/">documentation</a> and <a
-href="http://llvm.cs.uiuc.edu/pubs/">publications describing algorithms and
-components implemented in LLVM</a>. The web page also contains versions of the
-API documentation which is up-to-date with the CVS version of the source code.
+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
+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>
<p>If you have any questions or comments about LLVM, please feel free to contact
-us via the <a href="http://llvm.cs.uiuc.edu/docs/#maillist"> mailing
+us via the <a href="http://llvm.org/docs/#maillist"> mailing
lists</a>.</p>
</div>
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- <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
+ <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
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