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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 Lattner2c17a892003-10-28 23:13:03 +0000[diff] [blame]85<li><a href="http://llvm.cs.uiuc.edu/PR62">C backend fails on constant cast expr to ptr-to-anonymous struct</a></li>
Chris Lattner287b6212003-10-29 01:26:07 +0000[diff] [blame^]86<li><a href="http://llvm.cs.uiuc.edu/PR63">#ident is not recognized by C frontend</a></li>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]87</ol><p>
88
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]89At this time, LLVM is known to work properly with SPEC CPU 2000, the Olden
90benchmarks, and the Ptrdist benchmarks among many other programs. Note however
91that the Sparc and X86 backends do not currently support exception throwing or
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]92long jumping (including 253.perlbmk in SPEC). For these programs you must use
93the C backend.<p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]94
95
96<!-- *********************************************************************** -->
97</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
98<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
99<a name="portability">Portability and Supported Platforms
100</b></font></td></tr></table><ul>
101<!-- *********************************************************************** -->
102
Brian Gaeke15a2a252003-10-22 18:19:08 +0000[diff] [blame]103LLVM has only been extensively tested on Intel and AMD machines running Red
104Hat Linux, and Sun UltraSPARC workstations running Solaris 8.
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]105The core LLVM infrastructure uses "autoconf" for portability, so hopefully we
106work on more platforms than that. However, it is extremely likely that we
107missed something. We welcome portability patches and error messages.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]108
109
110<!-- *********************************************************************** -->
111</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
112<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]113<a name="knownproblems">Known Problems
114</b></font></td></tr></table><ul>
115<!-- *********************************************************************** -->
116
117This section contains all known problems with the LLVM system, listed by
118component. As new problems are discovered, they will be added to these
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]119sections.
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]120
121
122<!-- _______________________________________________________________________ -->
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]123<!--
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]124</ul><h4><a name="portability"><hr size=0>Portability Problems</h4><ul>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]125-->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]126
127
128<!-- _______________________________________________________________________ -->
129</ul><h4><a name="core"><hr size=0>Known problems with the LLVM Core</h4><ul>
130
131<li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not work.<p>
132
133<li>The JIT does not use mutexes to protect its internal data structures. As
134 such, execution of a threaded program could cause these data structures to
135 be corrupted.<p>
136
137<li>It is not possible to <tt>dlopen</tt> an LLVM bytecode file in the JIT.<p>
138
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]139<li>Linking in static archive files (.a files) is very slow (there is no symbol
140table in the archive).
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]141
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]142<!-- _______________________________________________________________________ -->
143</ul><h4><a name="c-fe"><hr size=0>Known problems with the C front-end</h4><ul>
144
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]145</ul><b>Bugs:</b><ul><p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]146
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]147<li><a href="http://llvm.cs.uiuc.edu/PR6">Oversized integer bitfields cause crash</a>.<p>
148
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]149<li>C99 Variable sized arrays do not release stack memory when they go out of
150 scope. Thus, the following program may run out of stack space:
151<pre>
152 for (i = 0; i != 1000000; ++i) {
153 int X[n];
154 foo(X);
155 }
156</pre><p>
157
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]158</ul><b>Notes:</b><ul><p>
159
160<li>Inline assembly is not yet supported.<p>
161
162<li>"long double" is transformed by the front-end into "double". There is no
163 support for floating point data types of any size other than 32 and 64 bits.
164 <p>
165
Chris Lattner824b9a62003-10-02 05:09:46 +0000[diff] [blame]166<li>The following Unix system functionality has not been tested and may not work:
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]167<ol>
168 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
John Criswell97745952003-10-27 17:41:53 +0000[diff] [blame]169 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
170 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]171 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
172 - These functions have not been tested.
173</ol><p>
174
175<li>Although many GCC extensions are supported, some are not. In particular,
176 the following extensions are known to <b>not be</b> supported:
177 <ol>
178 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.
179 <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.
180 <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.
181 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.
182 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Extended%20Asm">Extended Asm</a>: Assembler instructions with C expressions as operands.
183 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands
184 <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.
185 <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.
186 <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.
187 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions.
188 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.
189 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables.
190 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.
191 </ol><p>
192
193 The following GCC extensions are <b>partially</b> supported. An ignored
194 attribute means that the LLVM compiler ignores the presence of the attribute,
195 but the code should still work. An unsupported attribute is one which is
196 ignored by the LLVM compiler, which will cause a different interpretation of
197 the program.<p>
198
199 <ol>
200 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
201 Arrays whose length is computed at run time.<br>
202 Supported, but allocated stack space is not freed until the function returns (noted above).
203
204 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
205 Declaring that functions have no side effects, or that they can never return.<br>
206 <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>,
207 <tt>warn_unused_result</tt>, <tt>weak</tt><br>
208 <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>
209 <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
210 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>, <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
211 <tt>fastcall</tt>, all other target specific attributes
212
213 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
214 Specifying attributes of variables.<br>
215 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
216 <tt>deprecated</tt>, <tt>transparent_union</tt>,
217 <tt>unused</tt>, <tt>weak</tt><br>
218 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
219 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
220 <tt>vector_size</tt>, <tt>dllimport</tt>,
221 <tt>dllexport</tt>, all target specific attributes.<br>
222
223 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.
224 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
225 <tt>deprecated</tt>, <tt>may_alias</tt>
226 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>
227 all target specific attributes.<br>
228 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
229 Other built-in functions.<br>
230 We support all builtins which have a C language equivalent (e.g.,
231 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
232 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
233 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt> (ignored).
234 </ol><p>
235
236
237 The following extensions <b>are</b> known to be supported:
238 <ol>
239 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.
240 <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]241 <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]242 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.
243 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.
244 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.
245 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.
246 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.
247 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.
248 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variadic-Macros.html#Variadic%20Macros">Variadic Macros</a>: Macros with a variable number of arguments.
249 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.
250 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Subscripting.html#Subscripting">Subscripting</a>: Any array can be subscripted, even if not an lvalue.
251 <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.
252 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.
253 <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.
254 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.
255
256 <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.
257 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.
258 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.
259
260 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.
261 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized.
262 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.
263 <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;.
264 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.
265 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).
266 <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.
267 <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.
268 <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.
269 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html#Unnamed%20Fields">Unnamed Fields</a>: Unnamed struct/union fields within structs/unions.
270 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.
271 </ol><p>
272
273 If you run into GCC extensions which have not been included in any of these
274 lists, please let us know (also including whether or not they work).
275
276
277<!-- _______________________________________________________________________ -->
278</ul><h4><a name="c++-fe"><hr size=0>Known problems with the C++ front-end</h4><ul>
279
John Criswell97745952003-10-27 17:41:53 +0000[diff] [blame]280For this release, the C++ front-end is considered to be fully functional but
281of <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]282
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]283</ul><b>Bugs</b>:<ul><p>
284
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]285<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
286 front-end</a><p>
287
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]288</ul><b>Notes</b>:<ul><p>
289
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]290<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
291parser is significantly more standards compliant (and picky) than prior GCC
292versions. For more information, see the C++ section of the <a
293href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.<p>
294
295<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]296 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]297 function and in the <tt>setjmp</tt> receiver function may not be run.
298 Objects in intervening stack frames will be destroyed however (which is
299 better than most compilers).<p>
300
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]301<li>The LLVM C++ front-end follows the <a
302 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
303 This document, which is not Itanium specific, specifies a standard for name
304 mangling, class layout, v-table layout, RTTI formats, and other C++
305 representation issues. Because we use this API, code generated by the LLVM
306 compilers should be binary compatible with machine code generated by other
307 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
308 <i>However</i>, the exception handling mechanism used by LLVM is very
309 different from the model used in the Itanium ABI, so <b>exceptions will not
310 interact correctly</b> .
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]311
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]312<li><a href="http://llvm.cs.uiuc.edu/PR11">Code for executing destructors when
313 unwinding is not shared</a> (this is a quality of implementation problem,
314 which does not effect functionality).<p>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]315
316
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]317<!-- _______________________________________________________________________ -->
318</ul><h4><a name="x86-be"><hr size=0>Known problems with the X86 back-end</h4><ul>
319
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]320<li>The X86 code generator <a
Chris Lattner0d4379a2003-10-08 06:01:38 +0000[diff] [blame]321href="http://llvm.cs.uiuc.edu/PR16">does not currently
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]322support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
323or calls the C <tt>longjmp</tt> function will abort.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]324
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]325
326<!-- _______________________________________________________________________ -->
327</ul><h4><a name="sparc-be"><hr size=0>Known problems with the Sparc back-end</h4><ul>
328
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]329<li>The Sparc code generator <a
Chris Lattner0d4379a2003-10-08 06:01:38 +0000[diff] [blame]330href="http://llvm.cs.uiuc.edu/PR15">does not currently
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]331support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
332or calls the C <tt>longjmp</tt> function will abort.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]333
334
335<!-- _______________________________________________________________________ -->
336</ul><h4><a name="c-be"><hr size=0>Known problems with the C back-end</h4><ul>
337
338<li>The C back-end produces code that violates the ANSI C Type-Based Alias
339Analysis rules. As such, special options may be necessary to compile the code
340(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
341problem probably cannot be fixed.<p>
342
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]343<li><a href="http://llvm.cs.uiuc.edu/PR33">Initializers for global variables</a>
344cannot include special floating point numbers like Not-A-Number or Infinity.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]345
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]346<li><a href="http://zion.cs.uiuc.edu/PR56">Zero arg vararg functions are not
347supported</a>. This should not affect LLVM produced by the C or C++
348frontends.<p>
349
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]350<li>The code produces by the C back-end has only been tested with the Sun CC and
351GCC compilers. It is possible that it will have to be adjusted to support other
352C compilers.<p>
353
354
355
356<!-- *********************************************************************** -->
357</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
358<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
359<a name="additionalinfo">Additional Information
360</b></font></td></tr></table><ul>
361<!-- *********************************************************************** -->
362
363A wide variety of additional information is available on the LLVM web page,
364including mailing lists publications describing algorithms and components
365implemented in LLVM. The web page also contains versions of the API
366documentation which is up-to-date with the CVS version of the source code. You
367can access versions of these documents specific to this release by going into
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]368the "<tt>llvm/doc/</tt>" directory in the LLVM tree.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]369
370If you have any questions or comments about LLVM, please feel free to contact us
371via the mailing lists.<p>
372
373
374<!-- *********************************************************************** -->
375</ul>
376<!-- *********************************************************************** -->
377
378<hr><font size-1>
379
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]380Maintained By: <a href="http://llvm.cs.uiuc.edu/">The LLVM Team</a><br>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]381<!-- Created: Wed Oct 1 17:38:54 CDT 2003 -->
382<!-- hhmts start -->
Chris Lattner287b6212003-10-29 01:26:07 +0000[diff] [blame^]383Last modified: Tue Oct 28 19:25:02 CST 2003
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]384<!-- hhmts end -->
385</body></html>