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