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 | <body> | 
 |  | 
 | <div class="doc_title">LLVM 1.7 Release Notes</div> | 
 |   | 
 | <ol> | 
 |   <li><a href="#intro">Introduction</a></li> | 
 |   <li><a href="#whatsnew">What's New?</a></li> | 
 |   <li><a href="GettingStarted.html">Installation Instructions</a></li> | 
 |   <li><a href="#portability">Portability and Supported Platforms</a></li> | 
 |   <li><a href="#knownproblems">Known Problems</a> | 
 |   <li><a href="#additionalinfo">Additional Information</a></li> | 
 | </ol> | 
 |  | 
 | <div class="doc_author"> | 
 |   <p>Written by the <a href="http://llvm.org">LLVM Team</a><p> | 
 | </div> | 
 |  | 
 | <!-- *********************************************************************** --> | 
 | <div class="doc_section"> | 
 |   <a name="intro">Introduction</a> | 
 | </div> | 
 | <!-- *********************************************************************** --> | 
 |  | 
 | <div class="doc_text"> | 
 |  | 
 | <p>This document contains the release notes for the LLVM compiler | 
 | infrastructure, release 1.7.  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.org/releases/">LLVM releases 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> | 
 |  | 
 | <p>For more information about LLVM, including information about the latest | 
 | release, please check out the <a href="http://llvm.org/">main LLVM | 
 | web site</a>.  If you have questions or comments, the <a | 
 | href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing | 
 | list</a> is a good place to send them.</p> | 
 |  | 
 | <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> | 
 |  | 
 | </div> | 
 |  | 
 | <!-- *********************************************************************** --> | 
 | <div class="doc_section"> | 
 |   <a name="whatsnew">What's New?</a> | 
 | </div> | 
 | <!-- *********************************************************************** --> | 
 |  | 
 | <div class="doc_text"> | 
 |  | 
 | <p>This is the seventh public release of the LLVM Compiler Infrastructure. This | 
 | release incorporates a large number of enhancements and additions (primarily in | 
 | the code generator), which combine to improve the quality of the code generated | 
 | by LLVM by up to 30% in some cases.  This release is also the first release to | 
 | have first-class support for Mac OS X: all of the major bugs have been shaken | 
 | out and it is now as well supported as Linux on X86.</p> | 
 |  | 
 | </div> | 
 |  | 
 | <!--=========================================================================--> | 
 | <div class="doc_subsection"> | 
 | <a name="newfeatures">New Features in LLVM 1.7cvs</a> | 
 | </div> | 
 |  | 
 | <div class="doc_text"> | 
 | <ul> | 
 | <li>New C front-end.</li> | 
 | <li>New SPARC backend.</li> | 
 | <li>Inline assembly support.</li> | 
 | </ul> | 
 | </div> | 
 |  | 
 | <!--=========================================================================--> | 
 | <div class="doc_subsection"> | 
 | <a name="changes">Significant changes in LLVM 1.7cvs</a> | 
 | </div> | 
 |  | 
 | <div class="doc_text"> | 
 | <ul> | 
 | <li>Removed the llvm.readport/llvm.writeport/llvm.readio/llvm.writeio | 
 |     intrinsics.</li> | 
 | <li>Separated the other intrinsics based on type.</li> | 
 | </ul> | 
 | </div> | 
 |  | 
 |  | 
 | <!-- *********************************************************************** --> | 
 | <div class="doc_section"> | 
 |   <a name="portability">Portability and Supported Platforms</a> | 
 | </div> | 
 | <!-- *********************************************************************** --> | 
 |  | 
 | <div class="doc_text"> | 
 |  | 
 | <p>LLVM is known to work on the following platforms:</p> | 
 |  | 
 | <ul> | 
 |   <li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD  | 
 |       (and probably other unix-like systems).</li> | 
 | <li>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.</li> | 
 | <li>Alpha-based machines running Debian GNU/Linux.</li> | 
 | <li>Itanium-based machines running Linux and HP-UX.</li> | 
 | </ul> | 
 |  | 
 | <p>The core LLVM infrastructure uses | 
 | <a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself | 
 | to the machine and operating system on which it is built.  However, minor | 
 | porting may be required to get LLVM to work on new platforms.  We welcome your | 
 | portability patches and reports of successful builds or error messages.</p> | 
 |  | 
 | </div> | 
 |  | 
 | <!-- *********************************************************************** --> | 
 | <div class="doc_section"> | 
 |   <a name="knownproblems">Known Problems</a> | 
 | </div> | 
 | <!-- *********************************************************************** --> | 
 |  | 
 | <div class="doc_text"> | 
 |  | 
 | <p>This section contains all known problems with the LLVM system, listed by | 
 | component.  As new problems are discovered, they will be added to these | 
 | sections.  If you run into a problem, please check the <a | 
 | href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if | 
 | there isn't already one.</p> | 
 |  | 
 | </div> | 
 |  | 
 | <!-- ======================================================================= --> | 
 | <div class="doc_subsection"> | 
 |   <a name="experimental">Experimental features included with this release</a> | 
 | </div> | 
 |  | 
 | <div class="doc_text"> | 
 |  | 
 | <p>The following components of this LLVM release are either untested, known to | 
 | 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> | 
 |  | 
 | <ul> | 
 | <li>The following passes are incomplete or buggy, and may be removed in future | 
 |     releases: <tt>-cee</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 IA64 code generator is experimental.</li> | 
 | <li>The Alpha JIT is experimental.</li> | 
 | </ul> | 
 |  | 
 | </div> | 
 |  | 
 | <!-- ======================================================================= --> | 
 | <div class="doc_subsection"> | 
 |   <a name="build">Known problems with the Build System</a> | 
 | </div> | 
 |  | 
 | <div class="doc_text"> | 
 |  | 
 | <ul> | 
 |   <li>The <a href="http://llvm.org/PR656">configure script sometimes fails on Solaris/Sparc</a>. A work around is documented in <a href="http://llvm.org/PR656">PR656.</a></li> | 
 | </ul> | 
 | </div> | 
 |  | 
 |  | 
 | <!-- ======================================================================= --> | 
 | <div class="doc_subsection"> | 
 |   <a name="core">Known problems with the LLVM Core</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> | 
 | </ul> | 
 | </div> | 
 |  | 
 | <!-- ======================================================================= --> | 
 | <div class="doc_subsection"> | 
 |   <a name="c-fe">Known problems with the C front-end</a> | 
 | </div> | 
 |  | 
 | <!-- _______________________________________________________________________ --> | 
 | <div class="doc_subsubsection">Bugs</div> | 
 |  | 
 | <div class="doc_text"> | 
 |  | 
 | These bugs are known for the old front-end.  The new GCC-4-based C front-end | 
 | suffers from none of these. | 
 |  | 
 | <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.org/PR162">with the largest union member</a>.</li> | 
 |  | 
 | </ul> | 
 | </div> | 
 |  | 
 | <!-- _______________________________________________________________________ --> | 
 | <div class="doc_subsubsection"> | 
 |   Notes | 
 | </div> | 
 |  | 
 | <div class="doc_text"> | 
 |  | 
 | <ul> | 
 |  | 
 | <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>used</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>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>used</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> | 
 |  | 
 | </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> | 
 |  | 
 | </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> | 
 |  | 
 | </ul> | 
 |  | 
 | </div> | 
 |  | 
 | <!-- _______________________________________________________________________ --> | 
 | <div class="doc_subsubsection"> | 
 |   Notes | 
 | </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> | 
 |  | 
 | </ul> | 
 |  | 
 | </div> | 
 |  | 
 | <!-- ======================================================================= --> | 
 | <div class="doc_subsection"> | 
 |   <a name="c-be">Known problems with the C 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.org/PR56">Zero arg vararg functions are not  | 
 | supported</a>.  This should not affect LLVM produced by the C or C++  | 
 | frontends.</li> | 
 |  | 
 | </ul> | 
 |  | 
 | </div> | 
 |  | 
 | <!-- ======================================================================= --> | 
 | <div class="doc_subsection"> | 
 |   <a name="x86-be">Known problems with the X86 back-end</a> | 
 | </div> | 
 |  | 
 | <div class="doc_text"> | 
 |  | 
 | <ul> | 
 | <li>None yet</li> | 
 | </ul> | 
 |  | 
 | </div> | 
 |  | 
 | <!-- ======================================================================= --> | 
 | <div class="doc_subsection"> | 
 |   <a name="ppc-be">Known problems with the PowerPC back-end</a> | 
 | </div> | 
 |  | 
 | <div class="doc_text"> | 
 |  | 
 | <ul> | 
 | <li>None yet</li> | 
 | </ul> | 
 |  | 
 | </div> | 
 |  | 
 | <!-- ======================================================================= --> | 
 | <div class="doc_subsection"> | 
 |   <a name="sparcv9-be">Known problems with the SparcV9 back-end</a> | 
 | </div> | 
 |  | 
 | <div class="doc_text"> | 
 |  | 
 | <ul> | 
 | <li><a href="http://llvm.org/PR60">[sparcv9] SparcV9 backend miscompiles | 
 | several programs in the LLVM test suite</a></li> | 
 | </ul> | 
 |  | 
 | </div> | 
 |  | 
 | <!-- ======================================================================= --> | 
 | <div class="doc_subsection"> | 
 |   <a name="alpha-be">Known problems with the Alpha back-end</a> | 
 | </div> | 
 |  | 
 | <div class="doc_text"> | 
 |  | 
 | <ul> | 
 |  | 
 | <li>On 21164s, some rare FP arithmetic sequences which may trap do not have the | 
 | appropriate nops inserted to ensure restartability.</li> | 
 |  | 
 | </ul> | 
 |  | 
 | </div> | 
 |  | 
 | <!-- ======================================================================= --> | 
 | <div class="doc_subsection"> | 
 |   <a name="ia64-be">Known problems with the IA64 back-end</a> | 
 | </div> | 
 |  | 
 | <div class="doc_text"> | 
 |  | 
 | <ul> | 
 |  | 
 | <li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are | 
 | made where the argument is not 16-byte aligned, as required on IA64. (Strictly | 
 | speaking this is not a bug in the IA64 back-end; it will also be encountered | 
 | when building C++ programs using the C back-end.)</li> | 
 |  | 
 | <li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64 | 
 | ABI compliant layout of v-tables</a>.  In particular, it just stores function | 
 | pointers instead of function descriptors in the vtable.  This bug prevents | 
 | mixing C++ code compiled with LLVM with C++ objects compiled by other C++ | 
 | compilers.</li> | 
 |  | 
 | <li>There are a few ABI violations which will lead to problems when mixing LLVM | 
 | output with code built with other compilers, particularly for floating-point | 
 | programs.</li> | 
 |  | 
 | <li>Defining vararg functions is not supported (but calling them is ok).</li> | 
 |  | 
 | </ul> | 
 |  | 
 | </div> | 
 |  | 
 | <!-- ======================================================================= --> | 
 | <div class="doc_subsection"> | 
 |   <a name="sparc">Known problems with the SPARC back-end</a> | 
 | </div> | 
 |  | 
 | <div class="doc_text"> | 
 |  | 
 | <ul> | 
 | <li>None yet.</li> | 
 | </ul> | 
 | </div> | 
 |  | 
 | <!-- *********************************************************************** --> | 
 | <div class="doc_section"> | 
 |   <a name="additionalinfo">Additional Information</a> | 
 | </div> | 
 | <!-- *********************************************************************** --> | 
 |  | 
 | <div class="doc_text"> | 
 |  | 
 | <p>A wide variety of additional information is available on the <a | 
 | href="http://llvm.org">LLVM web page</a>, including <a | 
 | href="http://llvm.org/docs/">documentation</a> and <a | 
 | href="http://llvm.org/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. | 
 | 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.org/docs/#maillist"> mailing | 
 | lists</a>.</p> | 
 |  | 
 | </div> | 
 |  | 
 | <!-- *********************************************************************** --> | 
 |  | 
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