RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-24 19:52:54 +01:00
Code Issues Projects Releases Wiki Activity
b06ee3dd65
llvm-mirror/docs/ReleaseNotes.html
Chris Lattner fc887cc3da add note about bit builtins newly supported 
llvm-svn: 21757
2005-05-07 02:21:21 +00:00

636 lines
28 KiB
HTML
Raw Blame History

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<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>
</head>
<body>
<div class="doc_title">LLVM 1.5 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.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 1.5. Here we describe the status of LLVM, including any
known problems and 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>
<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
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>
</div>
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="whatsnew">What's New?</a>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<p>This is the sixth public release of the LLVM compiler infrastructure.</p>
<p> At this time, LLVM is known to correctly compile a broad range of C and
C++ programs, including the SPEC CPU95 &amp; 2000 suite. TODO. It also includes
bug fixes for those problems found since the 1.4 release.</p>
</div>
<!--=========================================================================-->
<div class="doc_subsubsection">
<a name="newfeatures">This release implements the following new features:</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>LLVM includes new experimental native code generators for SparcV8,
Alpha, and IA64.</li>
<li>Support for Microsoft Visual Studio is improved, and <a
href="GettingStartedVS.html">now documented</a>.</li>
<li>Configuring LLVM to build targets selectively is now implemented, via the
<tt>--enable-targets=</tt> option. This feature is documented
<a href="GettingStarted.html#config">here</a>.</li>
<li>LLVM now supports <a href="LangRef.html#callingconv">custom and
target-specific calling conventions</a>.</li>
</ol>
</div>
<!--=========================================================================-->
<div class="doc_subsubsection">
In this release, the following missing features were implemented:
</div>
<div class="doc_text">
<ol>
<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>
</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.cs.uiuc.edu/PR448">Building LLVM in optimized mode
should no longer cause GCC to hit swap in the PowerPC backend.</a></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>Transition code for 1.0 style varargs was removed. </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.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>
</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>
</ol>
<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 &lt;-&gt; 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>
<!-- *********************************************************************** -->
<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 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-based Mac OS X systems, running 10.2 and above.</li>
<li>Alpha-based machines running Debian GNU/Linux</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.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 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 ports are experimental.</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><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/PR162">with the largest union member</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_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 &lt;ESC&gt;.</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>
<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="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="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/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="alpha-be">Known problems with the Alpha back-end</a>
</div>
<div class="doc_text">
<ul>
<li>On 21164s, some rare FP arithmatic sequences which may trap do not have the appropriate nops inserted to ensure restartability.</li>
<li>Vararg functions are not supported.</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 <a href="http://llvm.cs.uiuc.edu/docs/#maillist">mailing lists</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.
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>
<!-- *********************************************************************** -->
<hr>
<address>
<a href="http://jigsaw.w3.org/css-validator/check/referer"><img
src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
<a href="http://validator.w3.org/check/referer"><img
src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
<a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
Last modified: $Date$
</address>
</body>
</html>
Reference in New Issue View Git Blame Copy Permalink