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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>Alpha-based machines running Debian GNU/Linux</li>
213 <p>The core LLVM infrastructure uses
214 <a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
215 to the machine and operating system on which it is built. However, minor
216 porting may be required to get LLVM to work on new platforms. We welcome your
217 portability patches and reports of successful builds or error messages.</p>
221 <!-- *********************************************************************** -->
222 <div class="doc_section">
223 <a name="knownproblems">Known Problems</a>
225 <!-- *********************************************************************** -->
227 <div class="doc_text">
229 <p>This section contains all known problems with the LLVM system, listed by
230 component. As new problems are discovered, they will be added to these
231 sections. If you run into a problem, please check the <a
232 href="http://llvm.cs.uiuc.edu/bugs/">LLVM bug database</a> and submit a bug if
233 there isn't already one.</p>
237 <!-- ======================================================================= -->
238 <div class="doc_subsection">
239 <a name="experimental">Experimental features included with this release</a>
242 <div class="doc_text">
244 <p>The following components of this LLVM release are either untested, known to
245 be broken or unreliable, or are in early development. These components should
246 not be relied on, and bugs should not be filed against them, but they may be
247 useful to some people. In particular, if you would like to work on one of these
248 components, please contact us on the llvmdev list.</p>
251 <li>The following passes are incomplete or buggy, and may be removed in future
252 releases: <tt>-cee, -branch-combine, -instloops, -paths, -pre</tt></li>
253 <li>The <tt>llvm-db</tt> tool is in a very early stage of development, but can
254 be used to step through programs and inspect the stack.</li>
255 <li>The "iterative scan" register allocator (enabled with
256 <tt>-regalloc=iterativescan</tt>) is not stable.</li>
257 <li>The SparcV8, Alpha, and IA64 ports are experimental.</li>
262 <!-- ======================================================================= -->
263 <div class="doc_subsection">
264 <a name="core">Known problems with the LLVM Core</a>
267 <div class="doc_text">
270 <li>In the JIT, <tt>dlsym()</tt> on a symbol compiled by the JIT will not
272 <li>The JIT does not use mutexes to protect its internal data structures. As
273 such, execution of a threaded program could cause these data structures to be
276 <li><a href="http://llvm.cs.uiuc.edu/PR240">The lower-invoke pass does not
277 mark values live across a setjmp as volatile</a>. This missing feature
278 only affects targets whose setjmp/longjmp libraries do not save and restore
279 the entire register file.</li>
283 <!-- ======================================================================= -->
284 <div class="doc_subsection">
285 <a name="c-fe">Known problems with the C front-end</a>
288 <!-- _______________________________________________________________________ -->
289 <div class="doc_subsubsection">Bugs</div>
291 <div class="doc_text">
293 <li>C99 Variable sized arrays do not release stack memory when they go out of
294 scope. Thus, the following program may run out of stack space:
296 for (i = 0; i != 1000000; ++i) {
302 <li>Initialization of global union variables can only be done <a
303 href="http://llvm.cs.uiuc.edu/PR162">with the largest union member</a>.</li>
308 <!-- _______________________________________________________________________ -->
309 <div class="doc_subsubsection">
313 <div class="doc_text">
317 <li>Inline assembly is not yet supported.</li>
319 <li>"long double" is transformed by the front-end into "double". There is no
320 support for floating point data types of any size other than 32 and 64
323 <li>The following Unix system functionality has not been tested and may not
326 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
327 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
328 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
329 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
330 - These functions have not been tested.
333 <li>Although many GCC extensions are supported, some are not. In particular,
334 the following extensions are known to <b>not be</b> supported:
336 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
337 <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>
338 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
339 <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>
340 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
341 <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>
342 <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>
343 <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>
344 <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>
345 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
346 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
349 <p>The following GCC extensions are <b>partially</b> supported. An ignored
350 attribute means that the LLVM compiler ignores the presence of the attribute,
351 but the code should still work. An unsupported attribute is one which is
352 ignored by the LLVM compiler and will cause a different interpretation of
356 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
357 Arrays whose length is computed at run time.<br>
358 Supported, but allocated stack space is not freed until the function returns (noted above).</li>
360 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
362 Declaring that functions have no side effects or that they can never
365 <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
366 <tt>noreturn</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
368 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
370 <b>Ignored:</b> <tt>noinline</tt>,
371 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
372 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
374 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>,
375 <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
376 <tt>fastcall</tt>, all other target specific attributes</li>
378 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
379 Specifying attributes of variables.<br>
380 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
381 <tt>deprecated</tt>, <tt>transparent_union</tt>,
382 <tt>unused</tt>, <tt>weak</tt><br>
384 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
385 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
386 <tt>vector_size</tt>, <tt>dllimport</tt>,
387 <tt>dllexport</tt>, all target specific attributes.</li>
389 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.<br>
390 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
391 <tt>deprecated</tt>, <tt>may_alias</tt><br>
393 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
394 all target specific attributes.</li>
396 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
397 Other built-in functions.<br>
398 We support all builtins which have a C language equivalent (e.g.,
399 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
400 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
401 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
402 (currently ignored). We also support builtins for ISO C99 floating
403 point comparison macros (e.g., <tt>__builtin_islessequal</tt>),
404 <tt>__builtin_prefetch</tt>, <tt>__builtin_popcount[ll]</tt>,
405 <tt>__builtin_clz[ll]</tt>, and <tt>__builtin_ctz[ll]</tt>.</li>
408 <p>The following extensions <b>are</b> known to be supported:</p>
411 <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>
412 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
413 <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>
414 <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>
415 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
416 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
417 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
418 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
419 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
420 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
421 <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>
422 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
423 <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>
424 <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>
425 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
426 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
427 or arrays as values.</li>
428 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.</li>
429 <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>
430 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
431 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
432 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
433 <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>
434 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
435 <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>
436 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
437 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
438 <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>
439 <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>
440 <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>
441 <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>
442 <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>
443 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.</li>
448 <p>If you run into GCC extensions which have not been included in any of these
449 lists, please let us know (also including whether or not they work).</p>
453 <!-- ======================================================================= -->
454 <div class="doc_subsection">
455 <a name="c++-fe">Known problems with the C++ front-end</a>
458 <div class="doc_text">
460 <p>For this release, the C++ front-end is considered to be fully
461 tested and works for a number of non-trivial programs, including LLVM
466 <!-- _______________________________________________________________________ -->
467 <div class="doc_subsubsection">Bugs</div>
469 <div class="doc_text">
472 <li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
475 <li><b>IA-64 specific</b>: The C++ front-end does not use <a
476 href="http://llvm.cs.uiuc.edu/PR406">IA64 ABI compliant layout of v-tables</a>.
477 In particular, it just stores function pointers instead of function
478 descriptors in the vtable. This bug prevents mixing C++ code compiled with
479 LLVM with C++ objects compiled by other C++ compilers.</li>
485 <!-- _______________________________________________________________________ -->
486 <div class="doc_subsubsection">
490 <div class="doc_text">
494 <li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
495 parser is significantly more standards compliant (and picky) than prior GCC
496 versions. For more information, see the C++ section of the <a
497 href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.</li>
499 <li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
500 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
501 function and in the <tt>setjmp</tt> receiver function may not be run.
502 Objects in intervening stack frames will be destroyed, however (which is
503 better than most compilers).</li>
505 <li>The LLVM C++ front-end follows the <a
506 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
507 This document, which is not Itanium specific, specifies a standard for name
508 mangling, class layout, v-table layout, RTTI formats, and other C++
509 representation issues. Because we use this API, code generated by the LLVM
510 compilers should be binary compatible with machine code generated by other
511 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
512 <i>However</i>, the exception handling mechanism used by LLVM is very
513 different from the model used in the Itanium ABI, so <b>exceptions will not
514 interact correctly</b>. </li>
520 <!-- ======================================================================= -->
521 <div class="doc_subsection">
522 <a name="x86-be">Known problems with the X86 back-end</a>
525 <div class="doc_text">
533 <!-- ======================================================================= -->
534 <div class="doc_subsection">
535 <a name="sparcv9-be">Known problems with the SparcV9 back-end</a>
538 <div class="doc_text">
541 <li><a href="http://llvm.cs.uiuc.edu/PR60">[sparcv9] SparcV9 backend miscompiles
542 several programs in the LLVM test suite</a></li>
547 <!-- ======================================================================= -->
548 <div class="doc_subsection">
549 <a name="ppc-be">Known problems with the PowerPC back-end</a>
552 <div class="doc_text">
560 <!-- ======================================================================= -->
561 <div class="doc_subsection">
562 <a name="c-be">Known problems with the C back-end</a>
565 <div class="doc_text">
569 <li>The C back-end produces code that violates the ANSI C Type-Based Alias
570 Analysis rules. As such, special options may be necessary to compile the code
571 (for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
572 problem probably cannot be fixed.</li>
574 <li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
575 supported</a>. This should not affect LLVM produced by the C or C++
582 <!-- ======================================================================= -->
583 <div class="doc_subsection">
584 <a name="alpha-be">Known problems with the Alpha back-end</a>
587 <div class="doc_text">
591 <li>On 21164s, some rare FP arithmatic sequences which may trap do not have the appropriate nops inserted to ensure restartability.</li>
593 <li>Vararg functions are not supported.</li>
599 <!-- *********************************************************************** -->
600 <div class="doc_section">
601 <a name="additionalinfo">Additional Information</a>
603 <!-- *********************************************************************** -->
605 <div class="doc_text">
607 <p>A wide variety of additional information is available on the LLVM web page,
608 including <a href="http://llvm.cs.uiuc.edu/docs/#maillist">mailing lists</a> and
609 <a href="http://llvm.cs.uiuc.edu/pubs/">publications describing algorithms and
610 components implemented in LLVM</a>. The web page also contains versions of the
611 API documentation which is up-to-date with the CVS version of the source code.
612 You can access versions of these documents specific to this release by going
613 into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
615 <p>If you have any questions or comments about LLVM, please feel free to contact
616 us via the <a href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">mailing
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