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Chris Lattner12d90632003-10-27 01:31:14 +0000[diff] [blame]2<html><head><title>LLVM 1.1 Release Notes</title></head>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]3<body bgcolor=white>
4
5<table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
Chris Lattner12d90632003-10-27 01:31:14 +0000[diff] [blame]6<tr><td>&nbsp; <font size=+3 color="#EEEEFF" face="Georgia,Palatino,Times,Roman"><b>LLVM 1.1 Release Notes</b></font></td>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]7</tr></table>
8
9<ol>
Chris Lattner824b9a62003-10-02 05:09:46 +0000[diff] [blame]10 <li><a href="#intro">Introduction</a>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]11 <li><a href="#whatsnew">What's New?</a>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]12 <li><a href="#portability">Portability and Supported Platforms</a>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]13 <li><a href="#install-instructions">Installation Instructions</a>
14 <li><a href="#knownproblems">Known Problems</a>
15 <ul>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]16<!-- <li><a href="#portabilityprobs">Portability Problems</a> -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]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>
23 </ul>
24 <li><a href="#additionalinfo">Additional Information</a>
25 </ul>
26
27 <p><b>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a></b><p>
28</ol>
29
30
31<!-- *********************************************************************** -->
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<!-- *********************************************************************** -->
37
38This document contains the release notes for the LLVM compiler infrastructure,
Chris Lattner12d90632003-10-27 01:31:14 +0000[diff] [blame]39release 1.1. Here we describe the status of LLVM, including any known problems,
40and bug fixes from the previous release. The most up-to-date version of this
41document can be found on the <a
42href="http://llvm.cs.uiuc.edu/releases/1.1/">LLVM 1.1 web site</a>. If you are
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]43not reading this on the LLVM web pages, you should probably go there, because
44this document may be updated after the release.<p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]45
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]46For more information about LLVM, including information about potentially more
47current releases, please check out the <a href="http://llvm.cs.uiuc.edu">main
48web site</a>. If you have questions or comments, the <a
49href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
50list</a> is a good place to send them.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]51
Chris Lattner12d90632003-10-27 01:31:14 +0000[diff] [blame]52Note that if you are reading this file from CVS, that this document applies to
53the <i>next</i> release, not the previous one. To see the release notes for the
54previous release, see the <a href="http://llvm.cs.uiuc.edu/releases/">releases
55page</a>.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]56
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<!-- *********************************************************************** -->
63
Chris Lattner12d90632003-10-27 01:31:14 +0000[diff] [blame]64This is the second public release of the LLVM compiler infrastructure. This
65release implements the following new features:<p>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]66
67<ol>
Chris Lattner12d90632003-10-27 01:31:14 +0000[diff] [blame]68<li>temp</li>
69<li>temp</li>
70<li>temp</li>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]71</ol><p>
72
Chris Lattner89ca2b82003-10-27 17:06:39 +0000[diff] [blame]73In this release, the following Quality of Implementation issues were fixed:<p>
74
75<ol>
76<li><a href="http://llvm.cs.uiuc.edu/PR29">C++ front-end is not generating linkonce linkage type when it can</a></li>
77</ol><p>
78
Chris Lattnerf7100202003-10-27 05:41:39 +0000[diff] [blame]79In this release, the following bugs in the previous release were fixed:<p>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]80
81<ol>
Chris Lattnerf7100202003-10-27 05:41:39 +0000[diff] [blame]82<li><a href="http://llvm.cs.uiuc.edu/PR57">[inliner] Inlining invoke with PHI in unwind target is broken</a></li>
Chris Lattner89ca2b82003-10-27 17:06:39 +0000[diff] [blame]83<li><a href="http://llvm.cs.uiuc.edu/PR58">[linker] linkonce globals should link successfully to external globals</a></li>
Chris Lattner4ad4b3a2003-10-27 17:58:57 +0000[diff] [blame]84<li><a href="http://llvm.cs.uiuc.edu/PR59">C++ frontend can crash when compiling virtual base classes</a></li>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]85</ol><p>
86
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]87At this time, LLVM is known to work properly with SPEC CPU 2000, the Olden
88benchmarks, and the Ptrdist benchmarks among many other programs. Note however
89that the Sparc and X86 backends do not currently support exception throwing or
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]90long jumping (including 253.perlbmk in SPEC). For these programs you must use
91the C backend.<p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]92
93
94<!-- *********************************************************************** -->
95</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
96<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
97<a name="portability">Portability and Supported Platforms
98</b></font></td></tr></table><ul>
99<!-- *********************************************************************** -->
100
Brian Gaeke15a2a252003-10-22 18:19:08 +0000[diff] [blame]101LLVM has only been extensively tested on Intel and AMD machines running Red
102Hat Linux, and Sun UltraSPARC workstations running Solaris 8.
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]103The core LLVM infrastructure uses "autoconf" for portability, so hopefully we
104work on more platforms than that. However, it is extremely likely that we
105missed something. We welcome portability patches and error messages.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]106
107
108<!-- *********************************************************************** -->
109</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
110<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]111<a name="knownproblems">Known Problems
112</b></font></td></tr></table><ul>
113<!-- *********************************************************************** -->
114
115This section contains all known problems with the LLVM system, listed by
116component. As new problems are discovered, they will be added to these
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]117sections.
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]118
119
120<!-- _______________________________________________________________________ -->
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]121<!--
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]122</ul><h4><a name="portability"><hr size=0>Portability Problems</h4><ul>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]123-->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]124
125
126<!-- _______________________________________________________________________ -->
127</ul><h4><a name="core"><hr size=0>Known problems with the LLVM Core</h4><ul>
128
129<li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not work.<p>
130
131<li>The JIT does not use mutexes to protect its internal data structures. As
132 such, execution of a threaded program could cause these data structures to
133 be corrupted.<p>
134
135<li>It is not possible to <tt>dlopen</tt> an LLVM bytecode file in the JIT.<p>
136
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]137<li>Linking in static archive files (.a files) is very slow (there is no symbol
138table in the archive).
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]139
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]140<!-- _______________________________________________________________________ -->
141</ul><h4><a name="c-fe"><hr size=0>Known problems with the C front-end</h4><ul>
142
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame^]143</ul><b>Bugs:</b><ul><p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]144
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame^]145<li><a href="http://llvm.cs.uiuc.edu/PR6">Oversized integer bitfields cause crash</a>.<p>
146
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]147<li>C99 Variable sized arrays do not release stack memory when they go out of
148 scope. Thus, the following program may run out of stack space:
149<pre>
150 for (i = 0; i != 1000000; ++i) {
151 int X[n];
152 foo(X);
153 }
154</pre><p>
155
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame^]156</ul><b>Notes:</b><ul><p>
157
158<li>Inline assembly is not yet supported.<p>
159
160<li>"long double" is transformed by the front-end into "double". There is no
161 support for floating point data types of any size other than 32 and 64 bits.
162 <p>
163
Chris Lattner824b9a62003-10-02 05:09:46 +0000[diff] [blame]164<li>The following Unix system functionality has not been tested and may not work:
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]165<ol>
166 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
John Criswell97745952003-10-27 17:41:53 +0000[diff] [blame]167 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
168 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]169 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
170 - These functions have not been tested.
171</ol><p>
172
173<li>Although many GCC extensions are supported, some are not. In particular,
174 the following extensions are known to <b>not be</b> supported:
175 <ol>
176 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.
177 <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.
178 <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.
179 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.
180 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Extended%20Asm">Extended Asm</a>: Assembler instructions with C expressions as operands.
181 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands
182 <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.
183 <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.
184 <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.
185 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions.
186 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.
187 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables.
188 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.
189 </ol><p>
190
191 The following GCC extensions are <b>partially</b> supported. An ignored
192 attribute means that the LLVM compiler ignores the presence of the attribute,
193 but the code should still work. An unsupported attribute is one which is
194 ignored by the LLVM compiler, which will cause a different interpretation of
195 the program.<p>
196
197 <ol>
198 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
199 Arrays whose length is computed at run time.<br>
200 Supported, but allocated stack space is not freed until the function returns (noted above).
201
202 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
203 Declaring that functions have no side effects, or that they can never return.<br>
204 <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>,
205 <tt>warn_unused_result</tt>, <tt>weak</tt><br>
206 <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>
207 <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
208 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>, <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
209 <tt>fastcall</tt>, all other target specific attributes
210
211 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
212 Specifying attributes of variables.<br>
213 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
214 <tt>deprecated</tt>, <tt>transparent_union</tt>,
215 <tt>unused</tt>, <tt>weak</tt><br>
216 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
217 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
218 <tt>vector_size</tt>, <tt>dllimport</tt>,
219 <tt>dllexport</tt>, all target specific attributes.<br>
220
221 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.
222 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
223 <tt>deprecated</tt>, <tt>may_alias</tt>
224 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>
225 all target specific attributes.<br>
226 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
227 Other built-in functions.<br>
228 We support all builtins which have a C language equivalent (e.g.,
229 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
230 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
231 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt> (ignored).
232 </ol><p>
233
234
235 The following extensions <b>are</b> known to be supported:
236 <ol>
237 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.
238 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Typeof.html#Typeof">Typeof</a>: <code>typeof</code>: referring to the type of an expression.
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]239 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]240 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.
241 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.
242 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.
243 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.
244 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.
245 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.
246 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variadic-Macros.html#Variadic%20Macros">Variadic Macros</a>: Macros with a variable number of arguments.
247 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.
248 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Subscripting.html#Subscripting">Subscripting</a>: Any array can be subscripted, even if not an lvalue.
249 <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.
250 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.
251 <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.
252 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.
253
254 <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.
255 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.
256 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.
257
258 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.
259 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized.
260 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.
261 <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;.
262 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.
263 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).
264 <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.
265 <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.
266 <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.
267 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html#Unnamed%20Fields">Unnamed Fields</a>: Unnamed struct/union fields within structs/unions.
268 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.
269 </ol><p>
270
271 If you run into GCC extensions which have not been included in any of these
272 lists, please let us know (also including whether or not they work).
273
274
275<!-- _______________________________________________________________________ -->
276</ul><h4><a name="c++-fe"><hr size=0>Known problems with the C++ front-end</h4><ul>
277
John Criswell97745952003-10-27 17:41:53 +0000[diff] [blame]278For this release, the C++ front-end is considered to be fully functional but
279of <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>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]280
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame^]281</ul><b>Bugs</b>:<ul><p>
282
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]283<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
284 front-end</a><p>
285
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame^]286</ul><b>Notes</b>:<ul><p>
287
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]288<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
289parser is significantly more standards compliant (and picky) than prior GCC
290versions. For more information, see the C++ section of the <a
291href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.<p>
292
293<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]294 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]295 function and in the <tt>setjmp</tt> receiver function may not be run.
296 Objects in intervening stack frames will be destroyed however (which is
297 better than most compilers).<p>
298
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]299<li>The LLVM C++ front-end follows the <a
300 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
301 This document, which is not Itanium specific, specifies a standard for name
302 mangling, class layout, v-table layout, RTTI formats, and other C++
303 representation issues. Because we use this API, code generated by the LLVM
304 compilers should be binary compatible with machine code generated by other
305 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
306 <i>However</i>, the exception handling mechanism used by LLVM is very
307 different from the model used in the Itanium ABI, so <b>exceptions will not
308 interact correctly</b> .
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]309
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame^]310<li><a href="http://llvm.cs.uiuc.edu/PR11">Code for executing destructors when
311 unwinding is not shared</a> (this is a quality of implementation problem,
312 which does not effect functionality).<p>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]313
314
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]315<!-- _______________________________________________________________________ -->
316</ul><h4><a name="x86-be"><hr size=0>Known problems with the X86 back-end</h4><ul>
317
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]318<li>The X86 code generator <a
Chris Lattner0d4379a2003-10-08 06:01:38 +0000[diff] [blame]319href="http://llvm.cs.uiuc.edu/PR16">does not currently
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]320support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
321or calls the C <tt>longjmp</tt> function will abort.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]322
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]323
324<!-- _______________________________________________________________________ -->
325</ul><h4><a name="sparc-be"><hr size=0>Known problems with the Sparc back-end</h4><ul>
326
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]327<li>The Sparc code generator <a
Chris Lattner0d4379a2003-10-08 06:01:38 +0000[diff] [blame]328href="http://llvm.cs.uiuc.edu/PR15">does not currently
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]329support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
330or calls the C <tt>longjmp</tt> function will abort.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]331
332
333<!-- _______________________________________________________________________ -->
334</ul><h4><a name="c-be"><hr size=0>Known problems with the C back-end</h4><ul>
335
336<li>The C back-end produces code that violates the ANSI C Type-Based Alias
337Analysis rules. As such, special options may be necessary to compile the code
338(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
339problem probably cannot be fixed.<p>
340
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]341<li><a href="http://llvm.cs.uiuc.edu/PR33">Initializers for global variables</a>
342cannot include special floating point numbers like Not-A-Number or Infinity.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]343
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]344<li><a href="http://zion.cs.uiuc.edu/PR56">Zero arg vararg functions are not
345supported</a>. This should not affect LLVM produced by the C or C++
346frontends.<p>
347
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]348<li>The code produces by the C back-end has only been tested with the Sun CC and
349GCC compilers. It is possible that it will have to be adjusted to support other
350C compilers.<p>
351
352
353
354<!-- *********************************************************************** -->
355</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
356<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
357<a name="additionalinfo">Additional Information
358</b></font></td></tr></table><ul>
359<!-- *********************************************************************** -->
360
361A wide variety of additional information is available on the LLVM web page,
362including mailing lists publications describing algorithms and components
363implemented in LLVM. The web page also contains versions of the API
364documentation which is up-to-date with the CVS version of the source code. You
365can access versions of these documents specific to this release by going into
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]366the "<tt>llvm/doc/</tt>" directory in the LLVM tree.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]367
368If you have any questions or comments about LLVM, please feel free to contact us
369via the mailing lists.<p>
370
371
372<!-- *********************************************************************** -->
373</ul>
374<!-- *********************************************************************** -->
375
376<hr><font size-1>
377
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]378Maintained By: <a href="http://llvm.cs.uiuc.edu/">The LLVM Team</a><br>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]379<!-- Created: Wed Oct 1 17:38:54 CDT 2003 -->
380<!-- hhmts start -->
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame^]381Last modified: Mon Oct 27 12:29:30 CST 2003
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]382<!-- hhmts end -->
383</body></html>