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2 <html><head><title>LLVM 1.1 Release Notes</title></head>
5 <table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
6 <tr><td> <font size=+3 color="#EEEEFF" face="Georgia,Palatino,Times,Roman"><b>LLVM 1.1 Release Notes</b></font></td>
10 <li><a href="#intro">Introduction</a>
11 <li><a href="#whatsnew">What's New?</a>
12 <li><a href="#portability">Portability and Supported Platforms</a>
13 <li><a href="#install-instructions">Installation Instructions</a>
14 <li><a href="#knownproblems">Known Problems</a>
16 <!-- <li><a href="#portabilityprobs">Portability Problems</a> -->
17 <li><a href="#core">Known problems with the LLVM Core</a>
18 <li><a href="#c-fe">Known problems with the C Front-end</a>
19 <li><a href="#c++-fe">Known problems with the C++ Front-end</a>
20 <li><a href="#x86-be">Known problems with the X86 Back-end</a>
21 <li><a href="#sparc-be">Known problems with the Sparc Back-end</a>
22 <li><a href="#c-be">Known problems with the C back-end</a>
24 <li><a href="#additionalinfo">Additional Information</a>
27 <p><b>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></b><p>
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32 <table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
33 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
34 <a name="intro">Introduction
35 </b></font></td></tr></table><ul>
36 <!-- *********************************************************************** -->
38 This document contains the release notes for the LLVM compiler infrastructure,
39 release 1.1. Here we describe the status of LLVM, including any known problems,
40 and bug fixes from the previous release. The most up-to-date version of this
41 document can be found on the <a
42 href="http://llvm.cs.uiuc.edu/releases/1.1/">LLVM 1.1 web site</a>. If you are
43 not reading this on the LLVM web pages, you should probably go there, because
44 this document may be updated after the release.<p>
46 For more information about LLVM, including information about potentially more
47 current releases, please check out the <a href="http://llvm.cs.uiuc.edu">main
48 web site</a>. If you have questions or comments, the <a
49 href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
50 list</a> is a good place to send them.<p>
52 Note that if you are reading this file from CVS, that this document applies to
53 the <i>next</i> release, not the previous one. To see the release notes for the
54 previous release, see the <a href="http://llvm.cs.uiuc.edu/releases/">releases
57 <!-- *********************************************************************** -->
58 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
59 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
60 <a name="whatsnew">What's New?
61 </b></font></td></tr></table><ul>
62 <!-- *********************************************************************** -->
64 This is the second public release of the LLVM compiler infrastructure. This
65 release implements the following new features:<p>
73 In this release, the following Quality of Implementation issues were fixed:<p>
76 <li><a href="http://llvm.cs.uiuc.edu/PR29">C++ front-end is not generating linkonce linkage type when it can</a></li>
79 In this release, the following bugs in the previous release were fixed:<p>
82 <li><a href="http://llvm.cs.uiuc.edu/PR57">[inliner] Inlining invoke with PHI in unwind target is broken</a></li>
83 <li><a href="http://llvm.cs.uiuc.edu/PR58">[linker] linkonce globals should link successfully to external globals</a></li>
84 <li><a href="http://llvm.cs.uiuc.edu/PR59">C++ frontend can crash when compiling virtual base classes</a></li>
85 <li><a href="http://llvm.cs.uiuc.edu/PR62">C backend fails on constant cast expr to ptr-to-anonymous struct</a></li>
86 <li><a href="http://llvm.cs.uiuc.edu/PR63">#ident is not recognized by C frontend</a></li>
87 <li><a href="http://llvm.cs.uiuc.edu/PR64">[constmerge] Constant merging pass merges constants with external linkage</a></li>
88 <li><a href="http://llvm.cs.uiuc.edu/PR65">C front-end miscompiles the builtin_expect intrinsic!</a></li>
89 <li><a href="http://llvm.cs.uiuc.edu/PR66">[scalarrepl] Scalar Replacement of aggregates is decimating structures it shouldn't be</a></li>
90 <li><a href="http://llvm.cs.uiuc.edu/PR67">1.0 precompiled libstdc++ does not include wchar_t support</a></li>
93 At this time, LLVM is known to work properly with SPEC CPU 2000, the Olden
94 benchmarks, and the Ptrdist benchmarks among many other programs. Note however
95 that the Sparc and X86 backends do not currently support exception throwing or
96 long jumping (including 253.perlbmk in SPEC). For these programs you must use
100 <!-- *********************************************************************** -->
101 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
102 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
103 <a name="portability">Portability and Supported Platforms
104 </b></font></td></tr></table><ul>
105 <!-- *********************************************************************** -->
107 LLVM has only been extensively tested on Intel and AMD machines running Red
108 Hat Linux, and Sun UltraSPARC workstations running Solaris 8.
109 The core LLVM infrastructure uses "autoconf" for portability, so hopefully we
110 work on more platforms than that. However, it is extremely likely that we
111 missed something. We welcome portability patches and error messages.<p>
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115 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
116 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
117 <a name="knownproblems">Known Problems
118 </b></font></td></tr></table><ul>
119 <!-- *********************************************************************** -->
121 This section contains all known problems with the LLVM system, listed by
122 component. As new problems are discovered, they will be added to these
126 <!-- _______________________________________________________________________ -->
128 </ul><h4><a name="portability"><hr size=0>Portability Problems</h4><ul>
132 <!-- _______________________________________________________________________ -->
133 </ul><h4><a name="core"><hr size=0>Known problems with the LLVM Core</h4><ul>
135 <li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not work.<p>
137 <li>The JIT does not use mutexes to protect its internal data structures. As
138 such, execution of a threaded program could cause these data structures to
141 <li>It is not possible to <tt>dlopen</tt> an LLVM bytecode file in the JIT.<p>
143 <li>Linking in static archive files (.a files) is very slow (there is no symbol
144 table in the archive).
146 <!-- _______________________________________________________________________ -->
147 </ul><h4><a name="c-fe"><hr size=0>Known problems with the C front-end</h4><ul>
149 </ul><b>Bugs:</b><ul><p>
151 <li><a href="http://llvm.cs.uiuc.edu/PR6">Oversized integer bitfields cause crash</a>.<p>
153 <li>C99 Variable sized arrays do not release stack memory when they go out of
154 scope. Thus, the following program may run out of stack space:
156 for (i = 0; i != 1000000; ++i) {
162 </ul><b>Notes:</b><ul><p>
164 <li>Inline assembly is not yet supported.<p>
166 <li>"long double" is transformed by the front-end into "double". There is no
167 support for floating point data types of any size other than 32 and 64 bits.
170 <li>The following Unix system functionality has not been tested and may not work:
172 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
173 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
174 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
175 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
176 - These functions have not been tested.
179 <li>Although many GCC extensions are supported, some are not. In particular,
180 the following extensions are known to <b>not be</b> supported:
182 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.
183 <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.
184 <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.
185 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.
186 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Extended%20Asm">Extended Asm</a>: Assembler instructions with C expressions as operands.
187 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands
188 <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.
189 <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.
190 <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.
191 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions.
192 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.
193 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables.
194 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.
197 The following GCC extensions are <b>partially</b> supported. An ignored
198 attribute means that the LLVM compiler ignores the presence of the attribute,
199 but the code should still work. An unsupported attribute is one which is
200 ignored by the LLVM compiler, which will cause a different interpretation of
204 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
205 Arrays whose length is computed at run time.<br>
206 Supported, but allocated stack space is not freed until the function returns (noted above).
208 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
209 Declaring that functions have no side effects, or that they can never return.<br>
210 <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>,
211 <tt>warn_unused_result</tt>, <tt>weak</tt><br>
212 <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>
213 <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
214 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>, <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
215 <tt>fastcall</tt>, all other target specific attributes
217 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
218 Specifying attributes of variables.<br>
219 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
220 <tt>deprecated</tt>, <tt>transparent_union</tt>,
221 <tt>unused</tt>, <tt>weak</tt><br>
222 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
223 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
224 <tt>vector_size</tt>, <tt>dllimport</tt>,
225 <tt>dllexport</tt>, all target specific attributes.<br>
227 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.
228 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
229 <tt>deprecated</tt>, <tt>may_alias</tt>
230 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>
231 all target specific attributes.<br>
232 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
233 Other built-in functions.<br>
234 We support all builtins which have a C language equivalent (e.g.,
235 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
236 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
237 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt> (ignored).
241 The following extensions <b>are</b> known to be supported:
243 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.
244 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Typeof.html#Typeof">Typeof</a>: <code>typeof</code>: referring to the type of an expression.
245 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.
246 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.
247 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.
248 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.
249 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.
250 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.
251 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.
252 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variadic-Macros.html#Variadic%20Macros">Variadic Macros</a>: Macros with a variable number of arguments.
253 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.
254 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Subscripting.html#Subscripting">Subscripting</a>: Any array can be subscripted, even if not an lvalue.
255 <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.
256 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.
257 <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.
258 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.
260 <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.
261 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.
262 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.
264 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.
265 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized.
266 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.
267 <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>.
268 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.
269 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).
270 <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.
271 <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.
272 <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.
273 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html#Unnamed%20Fields">Unnamed Fields</a>: Unnamed struct/union fields within structs/unions.
274 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.
277 If you run into GCC extensions which have not been included in any of these
278 lists, please let us know (also including whether or not they work).
281 <!-- _______________________________________________________________________ -->
282 </ul><h4><a name="c++-fe"><hr size=0>Known problems with the C++ front-end</h4><ul>
284 For this release, the C++ front-end is considered to be fully functional but
285 of <b>beta</b> quality. It has been tested and works for a number of simple programs that collectively exercise most of the language. Nevertheless, it has not been in use as long as the C front-end. Please report any bugs or problems.<p>
287 </ul><b>Bugs</b>:<ul><p>
289 <li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
292 </ul><b>Notes</b>:<ul><p>
294 <li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
295 parser is significantly more standards compliant (and picky) than prior GCC
296 versions. For more information, see the C++ section of the <a
297 href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.<p>
299 <li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
300 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
301 function and in the <tt>setjmp</tt> receiver function may not be run.
302 Objects in intervening stack frames will be destroyed however (which is
303 better than most compilers).<p>
305 <li>The LLVM C++ front-end follows the <a
306 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
307 This document, which is not Itanium specific, specifies a standard for name
308 mangling, class layout, v-table layout, RTTI formats, and other C++
309 representation issues. Because we use this API, code generated by the LLVM
310 compilers should be binary compatible with machine code generated by other
311 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
312 <i>However</i>, the exception handling mechanism used by LLVM is very
313 different from the model used in the Itanium ABI, so <b>exceptions will not
314 interact correctly</b> .
316 <li><a href="http://llvm.cs.uiuc.edu/PR11">Code for executing destructors when
317 unwinding is not shared</a> (this is a quality of implementation problem,
318 which does not effect functionality).<p>
321 <!-- _______________________________________________________________________ -->
322 </ul><h4><a name="x86-be"><hr size=0>Known problems with the X86 back-end</h4><ul>
324 <li>The X86 code generator <a
325 href="http://llvm.cs.uiuc.edu/PR16">does not currently
326 support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
327 or calls the C <tt>longjmp</tt> function will abort.<p>
330 <!-- _______________________________________________________________________ -->
331 </ul><h4><a name="sparc-be"><hr size=0>Known problems with the Sparc back-end</h4><ul>
333 <li>The Sparc code generator <a
334 href="http://llvm.cs.uiuc.edu/PR15">does not currently
335 support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
336 or calls the C <tt>longjmp</tt> function will abort.<p>
339 <!-- _______________________________________________________________________ -->
340 </ul><h4><a name="c-be"><hr size=0>Known problems with the C back-end</h4><ul>
342 <li>The C back-end produces code that violates the ANSI C Type-Based Alias
343 Analysis rules. As such, special options may be necessary to compile the code
344 (for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
345 problem probably cannot be fixed.<p>
347 <li><a href="http://llvm.cs.uiuc.edu/PR33">Initializers for global variables</a>
348 cannot include special floating point numbers like Not-A-Number or Infinity.<p>
350 <li><a href="http://zion.cs.uiuc.edu/PR56">Zero arg vararg functions are not
351 supported</a>. This should not affect LLVM produced by the C or C++
354 <li>The code produces by the C back-end has only been tested with the Sun CC and
355 GCC compilers. It is possible that it will have to be adjusted to support other
360 <!-- *********************************************************************** -->
361 </ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
362 <tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
363 <a name="additionalinfo">Additional Information
364 </b></font></td></tr></table><ul>
365 <!-- *********************************************************************** -->
367 A wide variety of additional information is available on the LLVM web page,
368 including mailing lists publications describing algorithms and components
369 implemented in LLVM. The web page also contains versions of the API
370 documentation which is up-to-date with the CVS version of the source code. You
371 can access versions of these documents specific to this release by going into
372 the "<tt>llvm/doc/</tt>" directory in the LLVM tree.<p>
374 If you have any questions or comments about LLVM, please feel free to contact us
375 via the mailing lists.<p>
378 <!-- *********************************************************************** -->
380 <!-- *********************************************************************** -->
384 Maintained By: <a href="http://llvm.cs.uiuc.edu/">The LLVM Team</a><br>
385 <!-- Created: Wed Oct 1 17:38:54 CDT 2003 -->
387 Last modified: Wed Oct 29 12:48:02 CST 2003