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| <title>LLVM 1.4 Release Notes</title> |
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| <body> |
| |
| <div class="doc_title">LLVM 1.4 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> |
| <ul> |
| <li><a href="#experimental">Experimental features included in this |
| release</a> |
| <li><a href="#core">Known problems with the LLVM Core</a> |
| <li><a href="#c-fe">Known problems with the C Front-end</a> |
| <li><a href="#c++-fe">Known problems with the C++ Front-end</a> |
| <li><a href="#x86-be">Known problems with the X86 Back-end</a> |
| <li><a href="#sparcv9-be">Known problems with the SparcV9 Back-end</a> |
| <li><a href="#c-be">Known problems with the C back-end</a> |
| </ul></li> |
| <li><a href="#additionalinfo">Additional Information</a></li> |
| </ol> |
| |
| <div class="doc_author"> |
| <p>Written by the <a href="http://llvm.cs.uiuc.edu">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 1.4. Here we describe the status of LLVM, including any |
| known problems and bug fixes 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/1.4/">LLVM 1.4 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 potentially more |
| current releases, please check out the <a href="http://llvm.cs.uiuc.edu">main |
| 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, 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> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
| <div class="doc_section"> |
| <a name="whatsnew">What's New?</a> |
| </div> |
| <!-- *********************************************************************** --> |
| |
| <div class="doc_text"> |
| |
| <p>This is the fifth public release of the LLVM compiler infrastructure.</p> |
| |
| <p> At this time, LLVM is known to correctly compile and run all C & C++ |
| SPEC CPU95 & 2000 benchmarks, the Olden benchmarks, and the Ptrdist |
| benchmarks, and <b>many</b> other programs. LLVM now also works |
| with a broad variety of C++ programs.</p> |
| |
| </div> |
| |
| <!--=========================================================================--> |
| <div class="doc_subsubsection"> |
| <a name="newfeatures">This release implements the following new features:</a> |
| </div> |
| |
| <div class="doc_text"> |
| |
| <ol> |
| <li><a href="http://llvm.org/PR257">move test/Programs out of the main llvm |
| tree</a></li> |
| <li></li> |
| </ol> |
| |
| </div> |
| |
| |
| <!--=========================================================================--> |
| <div class="doc_subsubsection"> |
| In this release, the following missing features were implemented: |
| </div> |
| |
| <div class="doc_text"> |
| |
| <ol> |
| <li><a href="http://llvm.org/PR419">JIT interface should support arbitrary |
| calls</a></li> |
| </ol> |
| |
| </div> |
| |
| <!--=========================================================================--> |
| <div class="doc_subsubsection"> |
| <a name="qualityofimp">In this release, the following Quality of Implementation |
| issues were fixed:</a> |
| </div> |
| |
| <div class="doc_text"> |
| |
| <ol> |
| <li><a href="http://llvm.org/PR426">[llvmg++] Tons of warnings are spewed when |
| linking to libstdc++</a></li> |
| <li><a href="http://llvm.org/PR352">include/{Support,Config} -> |
| include/llvm/{Support,Config}</a></li> |
| </ol> |
| |
| </div> |
| |
| <!--=========================================================================--> |
| <div class="doc_subsubsection"> |
| In this release, the following build problems were fixed: |
| </div> |
| |
| <div class="doc_text"> |
| <ol> |
| <li></li> |
| </ol> |
| </div> |
| |
| <!--=========================================================================--> |
| <div class="doc_subsubsection"> |
| <a name="codequality">This release includes the following Code Quality |
| improvements:</a> |
| </div> |
| |
| <div class="doc_text"> |
| <ol> |
| <li><a href="http://llvm.org/PR362">Ugly code generator for |
| std::min/std::max</a></li> |
| </ol> |
| </div> |
| |
| <!--=========================================================================--> |
| <div class="doc_subsubsection"> |
| <a name="bugfix">In this release, the following bugs in the previous release |
| were fixed:</a> |
| </div> |
| |
| <div class="doc_text"> |
| |
| <p>Bugs fixed in the LLVM Core:</p> |
| |
| <ol> |
| <li><a href="http://llvm.org/PR420">[licm] LICM invalidates alias analysis info |
| and uses broken information</a> (optimizer crash)</li> |
| <li><a href="http://llvm.org/PR422">[asmwriter] Asmwriter is really slow for |
| functions with lots of values</a></li> |
| <li><a href="http://llvm.org/PR423">[anders-aa] Andersen's AA is completely |
| broken in LLVM 1.3</a></li> |
| <li><a href="http://llvm.org/PR430">[bcwriter] Empty compaction tables |
| defined</a></li> |
| </ol> |
| |
| <p>Bugs in the C/C++ front-end:</p> |
| |
| <ol> |
| <li><a href="http://llvm.org/PR445">[llvmg++] not enough templates are instantiated</a></li> |
| <li><a href="http://llvm.org/PR450">[llvmg++] Extern const globals cannot be |
| marked 'constant' if they have nontrivial ctors or dtors</a></li> |
| </ol> |
| |
| <p>Bugs fixed in the Sparc V9 back-end:</p> |
| |
| <ol> |
| <li><a href="http://llvm.org/PR428">[sparcv9] regalloc assertion |
| failure with certain indirect calls</a></li> |
| </ol> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
| <div class="doc_section"> |
| <a name="portability">Portability and Supported Platforms</a> |
| </div> |
| <!-- *********************************************************************** --> |
| |
| <div class="doc_text"> |
| |
| <p>LLVM is known to work in 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 on Win32 with the Cygwin libraries.</li> |
| <li>PowerPC-based Mac OS X boxes, running 10.2 and above. Note that no JIT |
| support is available yet, and LLC support is beta. The C backend can be used |
| to produce stable code for this platform.</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> |
| |
| <p>Note that the LLVM build system does not currently support directories with |
| spaces on them when running on Win32/cygwin. We strongly recommend running |
| LLVM and the C frontend out of a top-level directory without spaces (e.g., |
| <tt>/cygdrive/c/llvm</tt>). Also, make sure to install <b>all</b> of the |
| cygwin packages. By default, many important tools are not installed that |
| are needed by the LLVM build process or test suite (e.g., /bin/time). Finally, |
| please make sure that there are no directories with spaces in them in your |
| PATH environment variable.</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.cs.uiuc.edu/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 PowerPC backend is incomplete and is known to miscompile several SPEC |
| benchmarks. The file <tt>llvm/lib/Target/PowerPC/README.txt</tt> has |
| details.</li> |
| <li>The following passes are incomplete or buggy: <tt>-pgmdep, -memdep, |
| -ipmodref, -cee, -branch-combine, -instloops, -paths</tt></li> |
| <li>The <tt>-pre</tt> pass is incomplete (there are cases it doesn't handle that |
| it should) and not thoroughly tested.</li> |
| <li>The <tt>llvm-ar</tt> tool is incomplete and probably buggy.</li> |
| <li>The <tt>llvm-db</tt> tool is in a very early stage of development.</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> |
| |
| <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>Linking in static archive files (.a files) is slow (there is no symbol |
| table in the archive).</li> |
| |
| <li>The gccld program <a href="http://llvm.cs.uiuc.edu/PR139">does not link |
| objects/archives in the order specified on the command line.</a></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> |
| </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"> |
| <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/bugs/show_bug.cgi?id=162">with the largest union |
| member</a>.</li> |
| |
| <li><a href="http://llvm.cs.uiuc.edu/PR244">[llvm-gcc] Error when an implicitly |
| external function is re-declared as static</a></li> |
| |
| </ul> |
| </div> |
| |
| <!-- _______________________________________________________________________ --> |
| <div class="doc_subsubsection"> |
| Notes |
| </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-Local.html#Thread-Local">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>constructor</tt>, <tt>destructor</tt>, <tt>unused</tt>, |
| <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br> |
| |
| <b>Ignored:</b> <tt>noreturn</tt>, <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>).</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---Comments.html#C++%20Comments">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 functional but |
| has not been tested as thoroughly as the C front-end. It has been tested and |
| works for a number of non-trivial programs, but there may be lurking bugs. |
| Please report any bugs or problems.</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> |
| |
| <li><b>IA-64 specific</b>: 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> |
| |
| </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="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="sparcv9-be">Known problems with the SparcV9 back-end</a> |
| </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> |
| |
| </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.cs.uiuc.edu/PR33">Initializers for global variables</a> |
| cannot include special floating point numbers like Not-A-Number or |
| Infinity.</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> |
| |
| </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 LLVM web page, |
| including mailing lists and publications describing algorithms and components |
| implemented in LLVM. 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://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">mailing |
| lists</a>.</p> |
| |
| </div> |
| |
| <!-- *********************************************************************** --> |
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