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7 <title>LLVM 1.5 Release Notes</title>
11 <div class="doc_title">LLVM 1.5 Release Notes</div>
14 <li><a href="#intro">Introduction</a></li>
15 <li><a href="#whatsnew">What's New?</a></li>
16 <li><a href="GettingStarted.html">Installation Instructions</a></li>
17 <li><a href="#portability">Portability and Supported Platforms</a></li>
18 <li><a href="#knownproblems">Known Problems</a>
19 <li><a href="#additionalinfo">Additional Information</a></li>
22 <div class="doc_author">
23 <p>Written by the <a href="http://llvm.cs.uiuc.edu">LLVM Team</a><p>
26 <!-- *********************************************************************** -->
27 <div class="doc_section">
28 <a name="intro">Introduction</a>
30 <!-- *********************************************************************** -->
32 <div class="doc_text">
34 <p>This document contains the release notes for the LLVM compiler
35 infrastructure, release 1.5. Here we describe the status of LLVM, including any
36 known problems and improvements from the previous release. The most up-to-date
37 version of this document can be found on the <a
38 href="http://llvm.cs.uiuc.edu/releases/1.5/">LLVM 1.5 web site</a>. If you are
39 not reading this on the LLVM web pages, you should probably go there because
40 this document may be updated after the release.</p>
42 <p>For more information about LLVM, including information about the latest
43 release, please check out the <a href="http://llvm.cs.uiuc.edu">main LLVM
44 web site</a>. If you have questions or comments, the <a
45 href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
46 list</a> is a good place to send them.</p>
48 <p>Note that if you are reading this file from CVS or the main LLVM web page,
49 this document applies to the <i>next</i> release, not the current one. To see
50 the release notes for the current or previous releases, see the <a
51 href="http://llvm.cs.uiuc.edu/releases/">releases page</a>.</p>
55 <!-- *********************************************************************** -->
56 <div class="doc_section">
57 <a name="whatsnew">What's New?</a>
59 <!-- *********************************************************************** -->
61 <div class="doc_text">
63 <p>This is the sixth public release of the LLVM compiler infrastructure.</p>
65 <p> At this time, LLVM is known to correctly compile a broad range of C and
66 C++ programs, including the SPEC CPU95 & 2000 suite. TODO. It also includes
67 bug fixes for those problems found since the 1.4 release.</p>
71 <!--=========================================================================-->
72 <div class="doc_subsubsection">
73 <a name="newfeatures">This release implements the following new features:</a>
76 <div class="doc_text">
78 <li>LLVM now includes an <a href="http://llvm.cs.uiuc.edu/PR415">
79 Interprocedural Sparse Conditional Constant Propagation</a> pass, named
80 -ipsccp, which is run by default at link-time.</li>
81 <li>LLVM 1.5 is now about 15% faster than LLVM 1.4 and its core data structures
82 use about 30% less memory.</li>
83 <li>LLVM includes new experimental native code generators for SparcV8,
85 <li>Support for Microsoft Visual Studio is improved, and <a
86 href="GettingStartedVS.html">now documented</a>.</li>
87 <li>Configuring LLVM to build targets selectively is now implemented, via the
88 <tt>--enable-targets=</tt> option. This feature is documented
89 <a href="GettingStarted.html#config">here</a>.</li>
90 <li>LLVM now supports <a href="LangRef.html#callingconv">custom and
91 target-specific calling conventions</a>.</li>
97 <!--=========================================================================-->
98 <div class="doc_subsubsection">
99 In this release, the following missing features were implemented:
102 <div class="doc_text">
105 <li>LLVM can now create native shared libraries with '<tt>llvm-gcc ...
106 -shared -Wl,-native</tt>' (or with <tt>-Wl,-native-cbe</tt>).</li>
107 <li>LLVM now supports a new "<a href="LangRef.html#i_prefetch">llvm.prefetch
108 </a>" intrinsic, and llvm-gcc now supports __builtin_prefetch.
109 <li>LLVM now supports intrinsics for <a href="LangRef.html#int_count">bit
110 counting</a> and llvm-gcc now implements the GCC
111 <tt>__builtin_popcount</tt>, <tt>__builtin_ctz</tt>, and
112 <tt>__builtin_clz</tt> builtins.</li>
117 <!--=========================================================================-->
118 <div class="doc_subsubsection">
119 <a name="qualityofimp">In this release, the following Quality of Implementation
120 issues were fixed:</a>
123 <div class="doc_text">
126 <li><a href="http://llvm.cs.uiuc.edu/PR448">Building LLVM in optimized mode
127 should no longer cause GCC to hit swap in the PowerPC backend.</a></li>
131 <!--=========================================================================-->
132 <div class="doc_subsubsection">
133 <a name="codequality">This release includes the following Code Quality
137 <div class="doc_text">
139 <li>Transition code for 1.0 style varargs was removed. </li>
143 <!--=========================================================================-->
144 <div class="doc_subsubsection">
145 <a name="bugfix">In this release, the following bugs in the previous release
149 <div class="doc_text">
152 <p>Bugs fixed in the LLVM Core:</p>
154 <li><a href="http://llvm.cs.uiuc.edu/PR491">[dse] DSE deletes stores that
155 are partially overwritten by smaller stores</a></li>
156 <li><a href="http://llvm.cs.uiuc.edu/PR548">[instcombine] miscompilation of
157 setcc or setcc in one case</a></li>
160 <p>Code Generator Bugs:</p>
162 <li><a href="http://llvm.cs.uiuc.edu/PR490">[cbackend] Logical constant
163 expressions (and/or/xor) not implemented</a></li>
164 <li><a href="http://llvm.cs.uiuc.edu/PR511">[cbackend] C backend does not
165 respect 'volatile'</a></li>
168 <p>Bugs in the C/C++ front-end:</p>
170 <li><a href="http://llvm.cs.uiuc.edu/PR487">[llvmgcc] llvm-gcc incorrectly
171 rejects some constant initializers involving the addresses of array
173 <li><a href="http://llvm.cs.uiuc.edu/PR501">[llvm-g++] Crash compiling
174 anonymous union</a></li>
175 <li><a href="http://llvm.cs.uiuc.edu/PR509">[llvm-g++] Do not use dynamic
176 initialization where static init will do</a></li>
177 <li><a href="http://llvm.cs.uiuc.edu/PR510">[llvmgcc] Field offset
178 miscalculated for some structure fields following bit fields</a></li>
179 <li><a href="http://llvm.cs.uiuc.edu/PR513">[llvm-g++] Temporary lifetimes
180 incorrect for short circuit logical operations</a></li>
181 <li><a href="http://llvm.cs.uiuc.edu/PR517">[llvm-gcc] Crash compiling
182 bitfield <-> aggregate assignment</a></li>
183 <li><a href="http://llvm.cs.uiuc.edu/PR520">[llvm-g++] Error compiling
184 virtual function thunk with an unnamed argument</a></li>
185 <li><a href="http://llvm.cs.uiuc.edu/PR522">[llvm-gcc] Crash on certain
186 C99 complex number routines</a></li>
187 <li><a href="http://llvm.cs.uiuc.edu/PR529">[llvm-g++] Crash using placement
188 new on an array type</a></li>
193 <!-- *********************************************************************** -->
194 <div class="doc_section">
195 <a name="portability">Portability and Supported Platforms</a>
197 <!-- *********************************************************************** -->
199 <div class="doc_text">
201 <p>LLVM is known to work on the following platforms:</p>
204 <li>Intel and AMD machines running Red Hat Linux and FreeBSD (and probably
205 other unix-like systems).</li>
206 <li>Sun UltraSPARC workstations running Solaris 8.</li>
207 <li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
208 support is available for native builds with Visual C++).</li>
209 <li>PowerPC-based Mac OS X systems, running 10.2 and above.</li>
210 <li>PowerPC-based Linux systems.</li>
211 <li>Alpha-based machines running Debian GNU/Linux.</li>
212 <li>Itanium-based machines running Linux and HP-UX.</li>
215 <p>The core LLVM infrastructure uses
216 <a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
217 to the machine and operating system on which it is built. However, minor
218 porting may be required to get LLVM to work on new platforms. We welcome your
219 portability patches and reports of successful builds or error messages.</p>
223 <!-- *********************************************************************** -->
224 <div class="doc_section">
225 <a name="knownproblems">Known Problems</a>
227 <!-- *********************************************************************** -->
229 <div class="doc_text">
231 <p>This section contains all known problems with the LLVM system, listed by
232 component. As new problems are discovered, they will be added to these
233 sections. If you run into a problem, please check the <a
234 href="http://llvm.cs.uiuc.edu/bugs/">LLVM bug database</a> and submit a bug if
235 there isn't already one.</p>
239 <!-- ======================================================================= -->
240 <div class="doc_subsection">
241 <a name="experimental">Experimental features included with this release</a>
244 <div class="doc_text">
246 <p>The following components of this LLVM release are either untested, known to
247 be broken or unreliable, or are in early development. These components should
248 not be relied on, and bugs should not be filed against them, but they may be
249 useful to some people. In particular, if you would like to work on one of these
250 components, please contact us on the llvmdev list.</p>
253 <li>The following passes are incomplete or buggy, and may be removed in future
254 releases: <tt>-cee, -branch-combine, -instloops, -paths, -pre</tt></li>
255 <li>The <tt>llvm-db</tt> tool is in a very early stage of development, but can
256 be used to step through programs and inspect the stack.</li>
257 <li>The "iterative scan" register allocator (enabled with
258 <tt>-regalloc=iterativescan</tt>) is not stable.</li>
259 <li>The SparcV8, Alpha, and IA64 code generators are experimental.</li>
264 <!-- ======================================================================= -->
265 <div class="doc_subsection">
266 <a name="core">Known problems with the LLVM Core</a>
269 <div class="doc_text">
272 <li>In the JIT, <tt>dlsym()</tt> on a symbol compiled by the JIT will not
274 <li>The JIT does not use mutexes to protect its internal data structures. As
275 such, execution of a threaded program could cause these data structures to be
278 <li><a href="http://llvm.cs.uiuc.edu/PR240">The lower-invoke pass does not
279 mark values live across a setjmp as volatile</a>. This missing feature
280 only affects targets whose setjmp/longjmp libraries do not save and restore
281 the entire register file.</li>
285 <!-- ======================================================================= -->
286 <div class="doc_subsection">
287 <a name="c-fe">Known problems with the C front-end</a>
290 <!-- _______________________________________________________________________ -->
291 <div class="doc_subsubsection">Bugs</div>
293 <div class="doc_text">
295 <li>C99 Variable sized arrays do not release stack memory when they go out of
296 scope. Thus, the following program may run out of stack space:
298 for (i = 0; i != 1000000; ++i) {
304 <li>Initialization of global union variables can only be done <a
305 href="http://llvm.cs.uiuc.edu/PR162">with the largest union member</a>.</li>
310 <!-- _______________________________________________________________________ -->
311 <div class="doc_subsubsection">
315 <div class="doc_text">
319 <li>Inline assembly is not yet supported.</li>
321 <li>"long double" is transformed by the front-end into "double". There is no
322 support for floating point data types of any size other than 32 and 64
325 <li>The following Unix system functionality has not been tested and may not
328 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
329 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
330 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
331 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
332 - These functions have not been tested.
335 <li>Although many GCC extensions are supported, some are not. In particular,
336 the following extensions are known to <b>not be</b> supported:
338 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
339 <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>
340 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
341 <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>
342 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
343 <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>
344 <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>
345 <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>
346 <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>
347 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
348 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
351 <p>The following GCC extensions are <b>partially</b> supported. An ignored
352 attribute means that the LLVM compiler ignores the presence of the attribute,
353 but the code should still work. An unsupported attribute is one which is
354 ignored by the LLVM compiler and will cause a different interpretation of
358 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
359 Arrays whose length is computed at run time.<br>
360 Supported, but allocated stack space is not freed until the function returns (noted above).</li>
362 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
364 Declaring that functions have no side effects or that they can never
367 <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
368 <tt>noreturn</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
370 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
372 <b>Ignored:</b> <tt>noinline</tt>,
373 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
374 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
376 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>,
377 <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
378 <tt>fastcall</tt>, all other target specific attributes</li>
380 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
381 Specifying attributes of variables.<br>
382 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
383 <tt>deprecated</tt>, <tt>transparent_union</tt>,
384 <tt>unused</tt>, <tt>weak</tt><br>
386 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
387 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
388 <tt>vector_size</tt>, <tt>dllimport</tt>,
389 <tt>dllexport</tt>, all target specific attributes.</li>
391 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.<br>
392 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
393 <tt>deprecated</tt>, <tt>may_alias</tt><br>
395 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
396 all target specific attributes.</li>
398 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
399 Other built-in functions.<br>
400 We support all builtins which have a C language equivalent (e.g.,
401 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
402 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
403 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
404 (currently ignored). We also support builtins for ISO C99 floating
405 point comparison macros (e.g., <tt>__builtin_islessequal</tt>),
406 <tt>__builtin_prefetch</tt>, <tt>__builtin_popcount[ll]</tt>,
407 <tt>__builtin_clz[ll]</tt>, and <tt>__builtin_ctz[ll]</tt>.</li>
410 <p>The following extensions <b>are</b> known to be supported:</p>
413 <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>
414 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
415 <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>
416 <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>
417 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
418 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
419 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
420 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
421 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
422 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
423 <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>
424 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
425 <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>
426 <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>
427 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
428 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
429 or arrays as values.</li>
430 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.</li>
431 <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>
432 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
433 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
434 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
435 <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>
436 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
437 <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>
438 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
439 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
440 <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>
441 <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>
442 <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>
443 <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>
444 <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>
445 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.</li>
450 <p>If you run into GCC extensions which have not been included in any of these
451 lists, please let us know (also including whether or not they work).</p>
455 <!-- ======================================================================= -->
456 <div class="doc_subsection">
457 <a name="c++-fe">Known problems with the C++ front-end</a>
460 <div class="doc_text">
462 <p>For this release, the C++ front-end is considered to be fully
463 tested and works for a number of non-trivial programs, including LLVM
468 <!-- _______________________________________________________________________ -->
469 <div class="doc_subsubsection">Bugs</div>
471 <div class="doc_text">
474 <li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
477 <li><b>IA-64 specific</b>: The C++ front-end does not use <a
478 href="http://llvm.cs.uiuc.edu/PR406">IA64 ABI compliant layout of v-tables</a>.
479 In particular, it just stores function pointers instead of function
480 descriptors in the vtable. This bug prevents mixing C++ code compiled with
481 LLVM with C++ objects compiled by other C++ compilers.</li>
487 <!-- _______________________________________________________________________ -->
488 <div class="doc_subsubsection">
492 <div class="doc_text">
496 <li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
497 parser is significantly more standards compliant (and picky) than prior GCC
498 versions. For more information, see the C++ section of the <a
499 href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.</li>
501 <li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
502 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
503 function and in the <tt>setjmp</tt> receiver function may not be run.
504 Objects in intervening stack frames will be destroyed, however (which is
505 better than most compilers).</li>
507 <li>The LLVM C++ front-end follows the <a
508 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
509 This document, which is not Itanium specific, specifies a standard for name
510 mangling, class layout, v-table layout, RTTI formats, and other C++
511 representation issues. Because we use this API, code generated by the LLVM
512 compilers should be binary compatible with machine code generated by other
513 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
514 <i>However</i>, the exception handling mechanism used by LLVM is very
515 different from the model used in the Itanium ABI, so <b>exceptions will not
516 interact correctly</b>. </li>
522 <!-- ======================================================================= -->
523 <div class="doc_subsection">
524 <a name="x86-be">Known problems with the X86 back-end</a>
527 <div class="doc_text">
535 <!-- ======================================================================= -->
536 <div class="doc_subsection">
537 <a name="sparcv9-be">Known problems with the SparcV9 back-end</a>
540 <div class="doc_text">
543 <li><a href="http://llvm.cs.uiuc.edu/PR60">[sparcv9] SparcV9 backend miscompiles
544 several programs in the LLVM test suite</a></li>
549 <!-- ======================================================================= -->
550 <div class="doc_subsection">
551 <a name="ppc-be">Known problems with the PowerPC back-end</a>
554 <div class="doc_text">
562 <!-- ======================================================================= -->
563 <div class="doc_subsection">
564 <a name="c-be">Known problems with the C back-end</a>
567 <div class="doc_text">
571 <li>The C back-end produces code that violates the ANSI C Type-Based Alias
572 Analysis rules. As such, special options may be necessary to compile the code
573 (for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
574 problem probably cannot be fixed.</li>
576 <li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
577 supported</a>. This should not affect LLVM produced by the C or C++
584 <!-- ======================================================================= -->
585 <div class="doc_subsection">
586 <a name="alpha-be">Known problems with the Alpha back-end</a>
589 <div class="doc_text">
593 <li>On 21164s, some rare FP arithmatic sequences which may trap do not have the appropriate nops inserted to ensure restartability.</li>
595 <li>Vararg functions are not supported.</li>
601 <!-- *********************************************************************** -->
602 <div class="doc_section">
603 <a name="additionalinfo">Additional Information</a>
605 <!-- *********************************************************************** -->
607 <div class="doc_text">
609 <p>A wide variety of additional information is available on the LLVM web page,
610 including <a href="http://llvm.cs.uiuc.edu/docs/#maillist">mailing lists</a> and
611 <a href="http://llvm.cs.uiuc.edu/pubs/">publications describing algorithms and
612 components implemented in LLVM</a>. The web page also contains versions of the
613 API documentation which is up-to-date with the CVS version of the source code.
614 You can access versions of these documents specific to this release by going
615 into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
617 <p>If you have any questions or comments about LLVM, please feel free to contact
618 us via the <a href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">mailing
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