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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
Chris Lattner3e2959e2003-11-08 05:22:09 +0000[diff] [blame]142LLVM has been extensively tested on Intel and AMD machines running Red
143Hat Linux, and Sun UltraSPARC workstations running Solaris 8. Additionally,
144LLVM works on Mac OS/X 10.3 and above, but only with the C back-end (no native
145backend for the PowerPC is available yet).
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]146The core LLVM infrastructure uses "autoconf" for portability, so hopefully we
Chris Lattner3e2959e2003-11-08 05:22:09 +0000[diff] [blame]147work on more platforms than that. However, it is likely that we
148missed something, and that minor porting is required to get LLVM to work on
149new platforms. We welcome portability patches and error messages.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]150
151
152<!-- *********************************************************************** -->
153</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
154<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]155<a name="knownproblems">Known Problems
156</b></font></td></tr></table><ul>
157<!-- *********************************************************************** -->
158
159This section contains all known problems with the LLVM system, listed by
160component. As new problems are discovered, they will be added to these
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]161sections.
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]162
163
164<!-- _______________________________________________________________________ -->
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]165<!--
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]166</ul><h4><a name="portability"><hr size=0>Portability Problems</h4><ul>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]167-->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]168
169
170<!-- _______________________________________________________________________ -->
171</ul><h4><a name="core"><hr size=0>Known problems with the LLVM Core</h4><ul>
172
173<li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not work.<p>
174
175<li>The JIT does not use mutexes to protect its internal data structures. As
176 such, execution of a threaded program could cause these data structures to
177 be corrupted.<p>
178
179<li>It is not possible to <tt>dlopen</tt> an LLVM bytecode file in the JIT.<p>
180
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]181<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]182table in the archive).<p>
183
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]184<li><a href="http://llvm.cs.uiuc.edu/PR82">LLVM cannot handle structures with
185more than 256 elements</a>.<p>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]186
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]187<!-- _______________________________________________________________________ -->
188</ul><h4><a name="c-fe"><hr size=0>Known problems with the C front-end</h4><ul>
189
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]190</ul><b>Bugs:</b><ul><p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]191
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]192<li><a href="http://llvm.cs.uiuc.edu/PR6">Oversized integer bitfields cause crash</a>.<p>
193
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]194<li>C99 Variable sized arrays do not release stack memory when they go out of
195 scope. Thus, the following program may run out of stack space:
196<pre>
197 for (i = 0; i != 1000000; ++i) {
198 int X[n];
199 foo(X);
200 }
201</pre><p>
202
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]203</ul><b>Notes:</b><ul><p>
204
205<li>Inline assembly is not yet supported.<p>
206
207<li>"long double" is transformed by the front-end into "double". There is no
208 support for floating point data types of any size other than 32 and 64 bits.
209 <p>
210
Chris Lattner824b9a62003-10-02 05:09:46 +0000[diff] [blame]211<li>The following Unix system functionality has not been tested and may not work:
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]212<ol>
213 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
John Criswell97745952003-10-27 17:41:53 +0000[diff] [blame]214 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
215 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]216 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
217 - These functions have not been tested.
218</ol><p>
219
220<li>Although many GCC extensions are supported, some are not. In particular,
221 the following extensions are known to <b>not be</b> supported:
222 <ol>
223 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.
224 <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.
225 <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.
226 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.
227 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Extended%20Asm">Extended Asm</a>: Assembler instructions with C expressions as operands.
228 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands
229 <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.
230 <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.
231 <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.
232 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions.
233 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.
234 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables.
235 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.
236 </ol><p>
237
238 The following GCC extensions are <b>partially</b> supported. An ignored
239 attribute means that the LLVM compiler ignores the presence of the attribute,
240 but the code should still work. An unsupported attribute is one which is
241 ignored by the LLVM compiler, which will cause a different interpretation of
242 the program.<p>
243
244 <ol>
245 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
246 Arrays whose length is computed at run time.<br>
247 Supported, but allocated stack space is not freed until the function returns (noted above).
248
249 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
250 Declaring that functions have no side effects, or that they can never return.<br>
251 <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>,
252 <tt>warn_unused_result</tt>, <tt>weak</tt><br>
253 <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>
254 <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
255 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>, <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
256 <tt>fastcall</tt>, all other target specific attributes
257
258 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
259 Specifying attributes of variables.<br>
260 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
261 <tt>deprecated</tt>, <tt>transparent_union</tt>,
262 <tt>unused</tt>, <tt>weak</tt><br>
263 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
264 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
265 <tt>vector_size</tt>, <tt>dllimport</tt>,
266 <tt>dllexport</tt>, all target specific attributes.<br>
267
268 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.
269 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
270 <tt>deprecated</tt>, <tt>may_alias</tt>
271 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>
272 all target specific attributes.<br>
273 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
274 Other built-in functions.<br>
275 We support all builtins which have a C language equivalent (e.g.,
276 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
277 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
278 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt> (ignored).
279 </ol><p>
280
281
282 The following extensions <b>are</b> known to be supported:
283 <ol>
284 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.
285 <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]286 <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]287 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.
288 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.
289 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.
290 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.
291 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.
292 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.
293 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variadic-Macros.html#Variadic%20Macros">Variadic Macros</a>: Macros with a variable number of arguments.
294 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.
295 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Subscripting.html#Subscripting">Subscripting</a>: Any array can be subscripted, even if not an lvalue.
296 <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.
297 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.
298 <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.
299 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.
300
301 <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.
302 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.
303 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.
304
305 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.
306 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized.
307 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.
308 <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;.
309 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.
310 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).
311 <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.
312 <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.
313 <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.
314 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html#Unnamed%20Fields">Unnamed Fields</a>: Unnamed struct/union fields within structs/unions.
315 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.
316 </ol><p>
317
318 If you run into GCC extensions which have not been included in any of these
319 lists, please let us know (also including whether or not they work).
320
321
322<!-- _______________________________________________________________________ -->
323</ul><h4><a name="c++-fe"><hr size=0>Known problems with the C++ front-end</h4><ul>
324
John Criswell97745952003-10-27 17:41:53 +0000[diff] [blame]325For this release, the C++ front-end is considered to be fully functional but
326of <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]327
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]328</ul><b>Bugs</b>:<ul><p>
329
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]330<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
331 front-end</a><p>
332
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]333</ul><b>Notes</b>:<ul><p>
334
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]335<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
336parser is significantly more standards compliant (and picky) than prior GCC
337versions. For more information, see the C++ section of the <a
338href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.<p>
339
340<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]341 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]342 function and in the <tt>setjmp</tt> receiver function may not be run.
343 Objects in intervening stack frames will be destroyed however (which is
344 better than most compilers).<p>
345
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]346<li>The LLVM C++ front-end follows the <a
347 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
348 This document, which is not Itanium specific, specifies a standard for name
349 mangling, class layout, v-table layout, RTTI formats, and other C++
350 representation issues. Because we use this API, code generated by the LLVM
351 compilers should be binary compatible with machine code generated by other
352 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
353 <i>However</i>, the exception handling mechanism used by LLVM is very
354 different from the model used in the Itanium ABI, so <b>exceptions will not
355 interact correctly</b> .
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]356
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]357<li><a href="http://llvm.cs.uiuc.edu/PR11">Code for executing destructors when
358 unwinding is not shared</a> (this is a quality of implementation problem,
359 which does not effect functionality).<p>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]360
361
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]362<!-- _______________________________________________________________________ -->
363</ul><h4><a name="x86-be"><hr size=0>Known problems with the X86 back-end</h4><ul>
364
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]365<li>The X86 code generator <a
Chris Lattner0d4379a2003-10-08 06:01:38 +0000[diff] [blame]366href="http://llvm.cs.uiuc.edu/PR16">does not currently
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]367support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
368or calls the C <tt>longjmp</tt> function will abort.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]369
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]370
371<!-- _______________________________________________________________________ -->
372</ul><h4><a name="sparc-be"><hr size=0>Known problems with the Sparc back-end</h4><ul>
373
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]374<li>The Sparc code generator <a
Chris Lattner0d4379a2003-10-08 06:01:38 +0000[diff] [blame]375href="http://llvm.cs.uiuc.edu/PR15">does not currently
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]376support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
377or calls the C <tt>longjmp</tt> function will abort.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]378
379
380<!-- _______________________________________________________________________ -->
381</ul><h4><a name="c-be"><hr size=0>Known problems with the C back-end</h4><ul>
382
383<li>The C back-end produces code that violates the ANSI C Type-Based Alias
384Analysis rules. As such, special options may be necessary to compile the code
385(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
386problem probably cannot be fixed.<p>
387
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]388<li><a href="http://llvm.cs.uiuc.edu/PR33">Initializers for global variables</a>
389cannot include special floating point numbers like Not-A-Number or Infinity.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]390
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]391<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]392supported</a>. This should not affect LLVM produced by the C or C++
393frontends.<p>
394
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]395<li><a href="http://llvm.cs.uiuc.edu/PR77">Variables in scope of output setjmp
396calls should be volatile</a>. Note that this does not effect correctness on
397many platforms.<p>
398
399<li>The code produces by the C back-end has only been tested with the Sun CC,
400GCC, and Intel compilers. It is possible that it will have to be adjusted to
401support other C compilers.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]402
403
404
405<!-- *********************************************************************** -->
406</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
407<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
408<a name="additionalinfo">Additional Information
409</b></font></td></tr></table><ul>
410<!-- *********************************************************************** -->
411
412A wide variety of additional information is available on the LLVM web page,
413including mailing lists publications describing algorithms and components
414implemented in LLVM. The web page also contains versions of the API
415documentation which is up-to-date with the CVS version of the source code. You
416can access versions of these documents specific to this release by going into
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]417the "<tt>llvm/doc/</tt>" directory in the LLVM tree.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]418
419If you have any questions or comments about LLVM, please feel free to contact us
420via the mailing lists.<p>
421
422
423<!-- *********************************************************************** -->
424</ul>
425<!-- *********************************************************************** -->
426
427<hr><font size-1>
428
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]429Maintained By: <a href="http://llvm.cs.uiuc.edu/">The LLVM Team</a><br>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]430<!-- Created: Wed Oct 1 17:38:54 CDT 2003 -->
431<!-- hhmts start -->
Chris Lattner0ef19062003-11-08 04:28:55 +0000[diff] [blame]432Last modified: Fri Nov 7 22:26:24 CST 2003
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]433<!-- hhmts end -->
434</body></html>