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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 Lattner0ef19062003-11-08 04:28:55 +0000[diff] [blame]68<li><a href="http://mail.cs.uiuc.edu/pipermail/llvmdev/2003-November/000528.html">A new LLVM profiler, similar to gprof</a> is available</li><p>
69
70<li>LLVM and the C/C++ front-end now compile on Mac OSX! Mac OSX users can now
71explore the LLVM optimizer with the C backend (note that LLVM requires GCC 3.3
72on Mac OSX).</li><p>
73
74</ol><p>
75
76In this release, the following missing features were implemented:<p>
77
78<ol>
79<li><a href="http://llvm.cs.uiuc.edu/PR88">The interpreter does not support
80invoke or unwind</a></li>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]81</ol><p>
82
Chris Lattner89ca2b82003-10-27 17:06:39 +0000[diff] [blame]83In this release, the following Quality of Implementation issues were fixed:<p>
84
85<ol>
Chris Lattner0ef19062003-11-08 04:28:55 +0000[diff] [blame]86
87<li><a href="http://llvm.cs.uiuc.edu/PR29">C++ front-end is not generating
88linkonce linkage type when it can</a></li>
89
90<li><a href="http://llvm.cs.uiuc.edu/PR84">C front-end doesn't emit
91getelementptr for address of array element</a></li>
92
Chris Lattner89ca2b82003-10-27 17:06:39 +0000[diff] [blame]93</ol><p>
94
Chris Lattner0ef19062003-11-08 04:28:55 +0000[diff] [blame]95
Chris Lattnerf7100202003-10-27 05:41:39 +0000[diff] [blame]96In this release, the following bugs in the previous release were fixed:<p>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]97
98<ol>
Chris Lattnerf7100202003-10-27 05:41:39 +0000[diff] [blame]99<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]100<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]101<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]102<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]103<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]104<li><a href="http://llvm.cs.uiuc.edu/PR64">[constmerge] Constant merging pass merges constants with external linkage</a></li>
105<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]106<li><a href="http://llvm.cs.uiuc.edu/PR66">[scalarrepl] Scalar Replacement of aggregates is decimating structures it shouldn't be</a></li>
107<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]108<li><a href="http://llvm.cs.uiuc.edu/PR68">llvmgcc asserts when compiling functions renamed with asm's</a></li>
109<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]110<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]111<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]112<li><a href="http://llvm.cs.uiuc.edu/PR72">[build problem] Callgraph.cpp not pulled in from libipa.a</a></li>
Chris Lattner8222eca2003-11-02 02:15:11 +0000[diff] [blame]113<li><a href="http://llvm.cs.uiuc.edu/PR79">llvm-gcc crashes compiling global union initializer</a></li>
114<li><a href="http://llvm.cs.uiuc.edu/PR80">C front-end crash on empty structure</a></li>
115<li><a href="http://llvm.cs.uiuc.edu/PR81">CFrontend crashes when compiling C99 compound expressions</a></li>
Chris Lattner2fb1ef82003-11-03 20:08:08 +0000[diff] [blame]116<li><a href="http://llvm.cs.uiuc.edu/PR83">[X86] Emission of global bool initializers broken</a></li>
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]117<li><a href="http://llvm.cs.uiuc.edu/PR87">llvm-gcc infinite loops on "case MAXINT:"</a></li>
Chris Lattnerde3bb572003-11-05 06:30:04 +0000[diff] [blame]118<li><a href="http://llvm.cs.uiuc.edu/PR89">[C++] Catch blocks make unparsable labels</a></li>
119<li><a href="http://llvm.cs.uiuc.edu/PR90">[C++] Initializing array with constructable objects fail</a></li>
120<li><a href="http://llvm.cs.uiuc.edu/PR91">[gccld] The -r (relinking) option does not work correctly</a></li>
Chris Lattner5b3fb032003-11-07 04:46:56 +0000[diff] [blame]121<li><a href="http://llvm.cs.uiuc.edu/PR92">[bcreader] Cannot read shift constant expressions from bytecode file</a></li>
122<li><a href="http://llvm.cs.uiuc.edu/PR93">[lowersetjmp] Lowersetjmp pass breaks dominance properties!</a></li>
123<li><a href="http://llvm.cs.uiuc.edu/PR94">llvm-gcc tries to add bools</a></li>
124<li><a href="http://llvm.cs.uiuc.edu/PR98">[buildscripts] Building into objdir with .o in it fails</a></li>
Chris Lattner7af4d5e2003-11-08 05:18:50 +0000[diff] [blame^]125<li><a href="http://llvm.cs.uiuc.edu/PR101">[setjmp/longjmp] Linking C programs which use setjmp/longjmp sometimes fail with references to the C++ runtime library!</a></li>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]126</ol><p>
127
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]128At this time, LLVM is known to work properly with SPEC CPU 2000, the Olden
129benchmarks, and the Ptrdist benchmarks among many other programs. Note however
130that the Sparc and X86 backends do not currently support exception throwing or
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]131long jumping (including 253.perlbmk in SPEC). For these programs you must use
132the C backend.<p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]133
134
135<!-- *********************************************************************** -->
136</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
137<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
138<a name="portability">Portability and Supported Platforms
139</b></font></td></tr></table><ul>
140<!-- *********************************************************************** -->
141
Brian Gaeke15a2a252003-10-22 18:19:08 +0000[diff] [blame]142LLVM has only been extensively tested on Intel and AMD machines running Red
143Hat Linux, and Sun UltraSPARC workstations running Solaris 8.
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]144The core LLVM infrastructure uses "autoconf" for portability, so hopefully we
145work on more platforms than that. However, it is extremely likely that we
146missed something. We welcome portability patches and error messages.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]147
148
149<!-- *********************************************************************** -->
150</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
151<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]152<a name="knownproblems">Known Problems
153</b></font></td></tr></table><ul>
154<!-- *********************************************************************** -->
155
156This section contains all known problems with the LLVM system, listed by
157component. As new problems are discovered, they will be added to these
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]158sections.
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]159
160
161<!-- _______________________________________________________________________ -->
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]162<!--
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]163</ul><h4><a name="portability"><hr size=0>Portability Problems</h4><ul>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]164-->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]165
166
167<!-- _______________________________________________________________________ -->
168</ul><h4><a name="core"><hr size=0>Known problems with the LLVM Core</h4><ul>
169
170<li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not work.<p>
171
172<li>The JIT does not use mutexes to protect its internal data structures. As
173 such, execution of a threaded program could cause these data structures to
174 be corrupted.<p>
175
176<li>It is not possible to <tt>dlopen</tt> an LLVM bytecode file in the JIT.<p>
177
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]178<li>Linking in static archive files (.a files) is very slow (there is no symbol
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]179table in the archive).<p>
180
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]181<li><a href="http://llvm.cs.uiuc.edu/PR82">LLVM cannot handle structures with
182more than 256 elements</a>.<p>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]183
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]184<!-- _______________________________________________________________________ -->
185</ul><h4><a name="c-fe"><hr size=0>Known problems with the C front-end</h4><ul>
186
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]187</ul><b>Bugs:</b><ul><p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]188
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]189<li><a href="http://llvm.cs.uiuc.edu/PR6">Oversized integer bitfields cause crash</a>.<p>
190
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]191<li>C99 Variable sized arrays do not release stack memory when they go out of
192 scope. Thus, the following program may run out of stack space:
193<pre>
194 for (i = 0; i != 1000000; ++i) {
195 int X[n];
196 foo(X);
197 }
198</pre><p>
199
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]200</ul><b>Notes:</b><ul><p>
201
202<li>Inline assembly is not yet supported.<p>
203
204<li>"long double" is transformed by the front-end into "double". There is no
205 support for floating point data types of any size other than 32 and 64 bits.
206 <p>
207
Chris Lattner824b9a62003-10-02 05:09:46 +0000[diff] [blame]208<li>The following Unix system functionality has not been tested and may not work:
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]209<ol>
210 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
John Criswell97745952003-10-27 17:41:53 +0000[diff] [blame]211 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
212 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]213 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
214 - These functions have not been tested.
215</ol><p>
216
217<li>Although many GCC extensions are supported, some are not. In particular,
218 the following extensions are known to <b>not be</b> supported:
219 <ol>
220 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.
221 <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.
222 <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.
223 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.
224 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Extended%20Asm">Extended Asm</a>: Assembler instructions with C expressions as operands.
225 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands
226 <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.
227 <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.
228 <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.
229 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions.
230 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.
231 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables.
232 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.
233 </ol><p>
234
235 The following GCC extensions are <b>partially</b> supported. An ignored
236 attribute means that the LLVM compiler ignores the presence of the attribute,
237 but the code should still work. An unsupported attribute is one which is
238 ignored by the LLVM compiler, which will cause a different interpretation of
239 the program.<p>
240
241 <ol>
242 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
243 Arrays whose length is computed at run time.<br>
244 Supported, but allocated stack space is not freed until the function returns (noted above).
245
246 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
247 Declaring that functions have no side effects, or that they can never return.<br>
248 <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>,
249 <tt>warn_unused_result</tt>, <tt>weak</tt><br>
250 <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>
251 <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
252 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>, <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
253 <tt>fastcall</tt>, all other target specific attributes
254
255 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
256 Specifying attributes of variables.<br>
257 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
258 <tt>deprecated</tt>, <tt>transparent_union</tt>,
259 <tt>unused</tt>, <tt>weak</tt><br>
260 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
261 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
262 <tt>vector_size</tt>, <tt>dllimport</tt>,
263 <tt>dllexport</tt>, all target specific attributes.<br>
264
265 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.
266 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
267 <tt>deprecated</tt>, <tt>may_alias</tt>
268 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>
269 all target specific attributes.<br>
270 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
271 Other built-in functions.<br>
272 We support all builtins which have a C language equivalent (e.g.,
273 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
274 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
275 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt> (ignored).
276 </ol><p>
277
278
279 The following extensions <b>are</b> known to be supported:
280 <ol>
281 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.
282 <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]283 <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]284 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.
285 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.
286 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.
287 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.
288 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.
289 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.
290 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variadic-Macros.html#Variadic%20Macros">Variadic Macros</a>: Macros with a variable number of arguments.
291 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.
292 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Subscripting.html#Subscripting">Subscripting</a>: Any array can be subscripted, even if not an lvalue.
293 <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.
294 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.
295 <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.
296 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.
297
298 <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.
299 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.
300 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.
301
302 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.
303 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized.
304 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.
305 <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;.
306 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.
307 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).
308 <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.
309 <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.
310 <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.
311 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html#Unnamed%20Fields">Unnamed Fields</a>: Unnamed struct/union fields within structs/unions.
312 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.
313 </ol><p>
314
315 If you run into GCC extensions which have not been included in any of these
316 lists, please let us know (also including whether or not they work).
317
318
319<!-- _______________________________________________________________________ -->
320</ul><h4><a name="c++-fe"><hr size=0>Known problems with the C++ front-end</h4><ul>
321
John Criswell97745952003-10-27 17:41:53 +0000[diff] [blame]322For this release, the C++ front-end is considered to be fully functional but
323of <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]324
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]325</ul><b>Bugs</b>:<ul><p>
326
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]327<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
328 front-end</a><p>
329
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]330</ul><b>Notes</b>:<ul><p>
331
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]332<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
333parser is significantly more standards compliant (and picky) than prior GCC
334versions. For more information, see the C++ section of the <a
335href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.<p>
336
337<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]338 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]339 function and in the <tt>setjmp</tt> receiver function may not be run.
340 Objects in intervening stack frames will be destroyed however (which is
341 better than most compilers).<p>
342
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]343<li>The LLVM C++ front-end follows the <a
344 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
345 This document, which is not Itanium specific, specifies a standard for name
346 mangling, class layout, v-table layout, RTTI formats, and other C++
347 representation issues. Because we use this API, code generated by the LLVM
348 compilers should be binary compatible with machine code generated by other
349 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
350 <i>However</i>, the exception handling mechanism used by LLVM is very
351 different from the model used in the Itanium ABI, so <b>exceptions will not
352 interact correctly</b> .
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]353
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]354<li><a href="http://llvm.cs.uiuc.edu/PR11">Code for executing destructors when
355 unwinding is not shared</a> (this is a quality of implementation problem,
356 which does not effect functionality).<p>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]357
358
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]359<!-- _______________________________________________________________________ -->
360</ul><h4><a name="x86-be"><hr size=0>Known problems with the X86 back-end</h4><ul>
361
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]362<li>The X86 code generator <a
Chris Lattner0d4379a2003-10-08 06:01:38 +0000[diff] [blame]363href="http://llvm.cs.uiuc.edu/PR16">does not currently
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]364support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
365or calls the C <tt>longjmp</tt> function will abort.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]366
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]367
368<!-- _______________________________________________________________________ -->
369</ul><h4><a name="sparc-be"><hr size=0>Known problems with the Sparc back-end</h4><ul>
370
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]371<li>The Sparc code generator <a
Chris Lattner0d4379a2003-10-08 06:01:38 +0000[diff] [blame]372href="http://llvm.cs.uiuc.edu/PR15">does not currently
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]373support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
374or calls the C <tt>longjmp</tt> function will abort.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]375
376
377<!-- _______________________________________________________________________ -->
378</ul><h4><a name="c-be"><hr size=0>Known problems with the C back-end</h4><ul>
379
380<li>The C back-end produces code that violates the ANSI C Type-Based Alias
381Analysis rules. As such, special options may be necessary to compile the code
382(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
383problem probably cannot be fixed.<p>
384
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]385<li><a href="http://llvm.cs.uiuc.edu/PR33">Initializers for global variables</a>
386cannot include special floating point numbers like Not-A-Number or Infinity.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]387
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]388<li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]389supported</a>. This should not affect LLVM produced by the C or C++
390frontends.<p>
391
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]392<li><a href="http://llvm.cs.uiuc.edu/PR77">Variables in scope of output setjmp
393calls should be volatile</a>. Note that this does not effect correctness on
394many platforms.<p>
395
396<li>The code produces by the C back-end has only been tested with the Sun CC,
397GCC, and Intel compilers. It is possible that it will have to be adjusted to
398support other C compilers.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]399
400
401
402<!-- *********************************************************************** -->
403</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
404<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
405<a name="additionalinfo">Additional Information
406</b></font></td></tr></table><ul>
407<!-- *********************************************************************** -->
408
409A wide variety of additional information is available on the LLVM web page,
410including mailing lists publications describing algorithms and components
411implemented in LLVM. The web page also contains versions of the API
412documentation which is up-to-date with the CVS version of the source code. You
413can access versions of these documents specific to this release by going into
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]414the "<tt>llvm/doc/</tt>" directory in the LLVM tree.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]415
416If you have any questions or comments about LLVM, please feel free to contact us
417via the mailing lists.<p>
418
419
420<!-- *********************************************************************** -->
421</ul>
422<!-- *********************************************************************** -->
423
424<hr><font size-1>
425
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]426Maintained By: <a href="http://llvm.cs.uiuc.edu/">The LLVM Team</a><br>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]427<!-- Created: Wed Oct 1 17:38:54 CDT 2003 -->
428<!-- hhmts start -->
Chris Lattner0ef19062003-11-08 04:28:55 +0000[diff] [blame]429Last modified: Fri Nov 7 22:26:24 CST 2003
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]430<!-- hhmts end -->
431</body></html>