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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 Lattner32547fe2003-10-29 07:17:13 +0000[diff] [blame]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>
Chris Lattner34790e52003-10-29 18:49:14 +0000[diff] [blame]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>
Chris Lattner05b958d2003-10-29 20:59:45 +0000[diff] [blame]91<li><a href="http://llvm.cs.uiuc.edu/PR68">llvmgcc asserts when compiling functions renamed with asm's</a></li>
92<li><a href="http://llvm.cs.uiuc.edu/PR69">C frontend crashes on some programs with lots of types.</a></li>
Chris Lattner36bd5d12003-10-30 01:20:42 +0000[diff] [blame]93<li><a href="http://llvm.cs.uiuc.edu/PR70">[instcombine] Resolving invoke inserts cast after terminator</a></li>
Chris Lattnerf9e8a0f2003-10-30 01:43:33 +0000[diff] [blame]94<li><a href="http://llvm.cs.uiuc.edu/PR71">llvm-as crashes when labels are used in phi nodes</a></li>
Chris Lattner3dcc7b92003-10-30 16:20:15 +0000[diff] [blame^]95<li><a href="http://llvm.cs.uiuc.edu/PR72">[build problem] Callgraph.cpp not pulled in from libipa.a</a></li>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]96</ol><p>
97
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]98At this time, LLVM is known to work properly with SPEC CPU 2000, the Olden
99benchmarks, and the Ptrdist benchmarks among many other programs. Note however
100that the Sparc and X86 backends do not currently support exception throwing or
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]101long jumping (including 253.perlbmk in SPEC). For these programs you must use
102the C backend.<p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]103
104
105<!-- *********************************************************************** -->
106</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
107<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
108<a name="portability">Portability and Supported Platforms
109</b></font></td></tr></table><ul>
110<!-- *********************************************************************** -->
111
Brian Gaeke15a2a252003-10-22 18:19:08 +0000[diff] [blame]112LLVM has only been extensively tested on Intel and AMD machines running Red
113Hat Linux, and Sun UltraSPARC workstations running Solaris 8.
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]114The core LLVM infrastructure uses "autoconf" for portability, so hopefully we
115work on more platforms than that. However, it is extremely likely that we
116missed something. We welcome portability patches and error messages.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]117
118
119<!-- *********************************************************************** -->
120</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
121<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]122<a name="knownproblems">Known Problems
123</b></font></td></tr></table><ul>
124<!-- *********************************************************************** -->
125
126This section contains all known problems with the LLVM system, listed by
127component. As new problems are discovered, they will be added to these
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]128sections.
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]129
130
131<!-- _______________________________________________________________________ -->
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]132<!--
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]133</ul><h4><a name="portability"><hr size=0>Portability Problems</h4><ul>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]134-->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]135
136
137<!-- _______________________________________________________________________ -->
138</ul><h4><a name="core"><hr size=0>Known problems with the LLVM Core</h4><ul>
139
140<li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not work.<p>
141
142<li>The JIT does not use mutexes to protect its internal data structures. As
143 such, execution of a threaded program could cause these data structures to
144 be corrupted.<p>
145
146<li>It is not possible to <tt>dlopen</tt> an LLVM bytecode file in the JIT.<p>
147
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]148<li>Linking in static archive files (.a files) is very slow (there is no symbol
149table in the archive).
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]150
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]151<!-- _______________________________________________________________________ -->
152</ul><h4><a name="c-fe"><hr size=0>Known problems with the C front-end</h4><ul>
153
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]154</ul><b>Bugs:</b><ul><p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]155
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]156<li><a href="http://llvm.cs.uiuc.edu/PR6">Oversized integer bitfields cause crash</a>.<p>
157
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]158<li>C99 Variable sized arrays do not release stack memory when they go out of
159 scope. Thus, the following program may run out of stack space:
160<pre>
161 for (i = 0; i != 1000000; ++i) {
162 int X[n];
163 foo(X);
164 }
165</pre><p>
166
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]167</ul><b>Notes:</b><ul><p>
168
169<li>Inline assembly is not yet supported.<p>
170
171<li>"long double" is transformed by the front-end into "double". There is no
172 support for floating point data types of any size other than 32 and 64 bits.
173 <p>
174
Chris Lattner824b9a62003-10-02 05:09:46 +0000[diff] [blame]175<li>The following Unix system functionality has not been tested and may not work:
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]176<ol>
177 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
John Criswell97745952003-10-27 17:41:53 +0000[diff] [blame]178 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
179 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]180 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
181 - These functions have not been tested.
182</ol><p>
183
184<li>Although many GCC extensions are supported, some are not. In particular,
185 the following extensions are known to <b>not be</b> supported:
186 <ol>
187 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.
188 <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.
189 <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.
190 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.
191 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Extended%20Asm">Extended Asm</a>: Assembler instructions with C expressions as operands.
192 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands
193 <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.
194 <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.
195 <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.
196 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions.
197 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.
198 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables.
199 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.
200 </ol><p>
201
202 The following GCC extensions are <b>partially</b> supported. An ignored
203 attribute means that the LLVM compiler ignores the presence of the attribute,
204 but the code should still work. An unsupported attribute is one which is
205 ignored by the LLVM compiler, which will cause a different interpretation of
206 the program.<p>
207
208 <ol>
209 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
210 Arrays whose length is computed at run time.<br>
211 Supported, but allocated stack space is not freed until the function returns (noted above).
212
213 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
214 Declaring that functions have no side effects, or that they can never return.<br>
215 <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>,
216 <tt>warn_unused_result</tt>, <tt>weak</tt><br>
217 <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>
218 <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
219 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>, <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
220 <tt>fastcall</tt>, all other target specific attributes
221
222 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
223 Specifying attributes of variables.<br>
224 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
225 <tt>deprecated</tt>, <tt>transparent_union</tt>,
226 <tt>unused</tt>, <tt>weak</tt><br>
227 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
228 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
229 <tt>vector_size</tt>, <tt>dllimport</tt>,
230 <tt>dllexport</tt>, all target specific attributes.<br>
231
232 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.
233 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
234 <tt>deprecated</tt>, <tt>may_alias</tt>
235 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>
236 all target specific attributes.<br>
237 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
238 Other built-in functions.<br>
239 We support all builtins which have a C language equivalent (e.g.,
240 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
241 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
242 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt> (ignored).
243 </ol><p>
244
245
246 The following extensions <b>are</b> known to be supported:
247 <ol>
248 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.
249 <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]250 <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]251 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.
252 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.
253 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.
254 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.
255 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.
256 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.
257 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variadic-Macros.html#Variadic%20Macros">Variadic Macros</a>: Macros with a variable number of arguments.
258 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.
259 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Subscripting.html#Subscripting">Subscripting</a>: Any array can be subscripted, even if not an lvalue.
260 <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.
261 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.
262 <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.
263 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.
264
265 <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.
266 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.
267 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.
268
269 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.
270 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized.
271 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.
272 <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;.
273 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.
274 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).
275 <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.
276 <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.
277 <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.
278 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html#Unnamed%20Fields">Unnamed Fields</a>: Unnamed struct/union fields within structs/unions.
279 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.
280 </ol><p>
281
282 If you run into GCC extensions which have not been included in any of these
283 lists, please let us know (also including whether or not they work).
284
285
286<!-- _______________________________________________________________________ -->
287</ul><h4><a name="c++-fe"><hr size=0>Known problems with the C++ front-end</h4><ul>
288
John Criswell97745952003-10-27 17:41:53 +0000[diff] [blame]289For this release, the C++ front-end is considered to be fully functional but
290of <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]291
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]292</ul><b>Bugs</b>:<ul><p>
293
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]294<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
295 front-end</a><p>
296
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]297</ul><b>Notes</b>:<ul><p>
298
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]299<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
300parser is significantly more standards compliant (and picky) than prior GCC
301versions. For more information, see the C++ section of the <a
302href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.<p>
303
304<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]305 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]306 function and in the <tt>setjmp</tt> receiver function may not be run.
307 Objects in intervening stack frames will be destroyed however (which is
308 better than most compilers).<p>
309
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]310<li>The LLVM C++ front-end follows the <a
311 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
312 This document, which is not Itanium specific, specifies a standard for name
313 mangling, class layout, v-table layout, RTTI formats, and other C++
314 representation issues. Because we use this API, code generated by the LLVM
315 compilers should be binary compatible with machine code generated by other
316 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
317 <i>However</i>, the exception handling mechanism used by LLVM is very
318 different from the model used in the Itanium ABI, so <b>exceptions will not
319 interact correctly</b> .
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]320
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]321<li><a href="http://llvm.cs.uiuc.edu/PR11">Code for executing destructors when
322 unwinding is not shared</a> (this is a quality of implementation problem,
323 which does not effect functionality).<p>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]324
325
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]326<!-- _______________________________________________________________________ -->
327</ul><h4><a name="x86-be"><hr size=0>Known problems with the X86 back-end</h4><ul>
328
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]329<li>The X86 code generator <a
Chris Lattner0d4379a2003-10-08 06:01:38 +0000[diff] [blame]330href="http://llvm.cs.uiuc.edu/PR16">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
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]334
335<!-- _______________________________________________________________________ -->
336</ul><h4><a name="sparc-be"><hr size=0>Known problems with the Sparc back-end</h4><ul>
337
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]338<li>The Sparc code generator <a
Chris Lattner0d4379a2003-10-08 06:01:38 +0000[diff] [blame]339href="http://llvm.cs.uiuc.edu/PR15">does not currently
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]340support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
341or calls the C <tt>longjmp</tt> function will abort.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]342
343
344<!-- _______________________________________________________________________ -->
345</ul><h4><a name="c-be"><hr size=0>Known problems with the C back-end</h4><ul>
346
347<li>The C back-end produces code that violates the ANSI C Type-Based Alias
348Analysis rules. As such, special options may be necessary to compile the code
349(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
350problem probably cannot be fixed.<p>
351
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]352<li><a href="http://llvm.cs.uiuc.edu/PR33">Initializers for global variables</a>
353cannot include special floating point numbers like Not-A-Number or Infinity.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]354
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]355<li><a href="http://zion.cs.uiuc.edu/PR56">Zero arg vararg functions are not
356supported</a>. This should not affect LLVM produced by the C or C++
357frontends.<p>
358
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]359<li>The code produces by the C back-end has only been tested with the Sun CC and
360GCC compilers. It is possible that it will have to be adjusted to support other
361C compilers.<p>
362
363
364
365<!-- *********************************************************************** -->
366</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
367<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
368<a name="additionalinfo">Additional Information
369</b></font></td></tr></table><ul>
370<!-- *********************************************************************** -->
371
372A wide variety of additional information is available on the LLVM web page,
373including mailing lists publications describing algorithms and components
374implemented in LLVM. The web page also contains versions of the API
375documentation which is up-to-date with the CVS version of the source code. You
376can access versions of these documents specific to this release by going into
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]377the "<tt>llvm/doc/</tt>" directory in the LLVM tree.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]378
379If you have any questions or comments about LLVM, please feel free to contact us
380via the mailing lists.<p>
381
382
383<!-- *********************************************************************** -->
384</ul>
385<!-- *********************************************************************** -->
386
387<hr><font size-1>
388
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]389Maintained By: <a href="http://llvm.cs.uiuc.edu/">The LLVM Team</a><br>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]390<!-- Created: Wed Oct 1 17:38:54 CDT 2003 -->
391<!-- hhmts start -->
Chris Lattner3dcc7b92003-10-30 16:20:15 +0000[diff] [blame^]392Last modified: Thu Oct 30 10:19:50 CST 2003
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]393<!-- hhmts end -->
394</body></html>