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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>
Chris Lattner11dde852003-11-09 19:44:07 +0000[diff] [blame]124<li><a href="http://llvm.cs.uiuc.edu/PR95">SymbolTable::getUniqueName is very inefficient</a></li>
Chris Lattner5b3fb032003-11-07 04:46:56 +0000[diff] [blame]125<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]126<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 Lattner11dde852003-11-09 19:44:07 +0000[diff] [blame]127<li><a href="http://llvm.cs.uiuc.edu/PR104">[c++] C++ Frontend lays out superclasses like anonymous bitfields!</a></li>
Brian Gaeke78792062003-11-11 21:52:34 +0000[diff] [blame]128<li><a href="http://llvm.cs.uiuc.edu/PR108">gccld -Lfoo -lfoo fails to find ./foo/libfoo.a</a></li>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]129</ol><p>
130
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]131At this time, LLVM is known to work properly with SPEC CPU 2000, the Olden
132benchmarks, and the Ptrdist benchmarks among many other programs. Note however
133that the Sparc and X86 backends do not currently support exception throwing or
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]134long jumping (including 253.perlbmk in SPEC). For these programs you must use
135the C backend.<p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]136
137
138<!-- *********************************************************************** -->
139</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
140<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
141<a name="portability">Portability and Supported Platforms
142</b></font></td></tr></table><ul>
143<!-- *********************************************************************** -->
144
Chris Lattner3e2959e2003-11-08 05:22:09 +0000[diff] [blame]145LLVM has been extensively tested on Intel and AMD machines running Red
146Hat Linux, and Sun UltraSPARC workstations running Solaris 8. Additionally,
147LLVM works on Mac OS/X 10.3 and above, but only with the C back-end (no native
148backend for the PowerPC is available yet).
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]149The core LLVM infrastructure uses "autoconf" for portability, so hopefully we
Chris Lattner3e2959e2003-11-08 05:22:09 +0000[diff] [blame]150work on more platforms than that. However, it is likely that we
151missed something, and that minor porting is required to get LLVM to work on
152new platforms. We welcome portability patches and error messages.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]153
154
155<!-- *********************************************************************** -->
156</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
157<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]158<a name="knownproblems">Known Problems
159</b></font></td></tr></table><ul>
160<!-- *********************************************************************** -->
161
162This section contains all known problems with the LLVM system, listed by
163component. As new problems are discovered, they will be added to these
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]164sections.
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]165
166
167<!-- _______________________________________________________________________ -->
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]168<!--
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]169</ul><h4><a name="portability"><hr size=0>Portability Problems</h4><ul>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]170-->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]171
172
173<!-- _______________________________________________________________________ -->
174</ul><h4><a name="core"><hr size=0>Known problems with the LLVM Core</h4><ul>
175
176<li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not work.<p>
177
178<li>The JIT does not use mutexes to protect its internal data structures. As
179 such, execution of a threaded program could cause these data structures to
180 be corrupted.<p>
181
182<li>It is not possible to <tt>dlopen</tt> an LLVM bytecode file in the JIT.<p>
183
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]184<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]185table in the archive).<p>
186
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]187<li><a href="http://llvm.cs.uiuc.edu/PR82">LLVM cannot handle structures with
188more than 256 elements</a>.<p>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]189
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]190<!-- _______________________________________________________________________ -->
191</ul><h4><a name="c-fe"><hr size=0>Known problems with the C front-end</h4><ul>
192
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]193</ul><b>Bugs:</b><ul><p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]194
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]195<li><a href="http://llvm.cs.uiuc.edu/PR6">Oversized integer bitfields cause crash</a>.<p>
196
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]197<li>C99 Variable sized arrays do not release stack memory when they go out of
198 scope. Thus, the following program may run out of stack space:
199<pre>
200 for (i = 0; i != 1000000; ++i) {
201 int X[n];
202 foo(X);
203 }
204</pre><p>
205
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]206</ul><b>Notes:</b><ul><p>
207
208<li>Inline assembly is not yet supported.<p>
209
210<li>"long double" is transformed by the front-end into "double". There is no
211 support for floating point data types of any size other than 32 and 64 bits.
212 <p>
213
Chris Lattner824b9a62003-10-02 05:09:46 +0000[diff] [blame]214<li>The following Unix system functionality has not been tested and may not work:
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]215<ol>
216 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
John Criswell97745952003-10-27 17:41:53 +0000[diff] [blame]217 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
218 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]219 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
220 - These functions have not been tested.
221</ol><p>
222
223<li>Although many GCC extensions are supported, some are not. In particular,
224 the following extensions are known to <b>not be</b> supported:
225 <ol>
226 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.
227 <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.
228 <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.
229 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.
230 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Extended%20Asm">Extended Asm</a>: Assembler instructions with C expressions as operands.
231 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands
232 <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.
233 <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.
234 <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.
235 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions.
236 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.
237 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables.
238 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.
239 </ol><p>
240
241 The following GCC extensions are <b>partially</b> supported. An ignored
242 attribute means that the LLVM compiler ignores the presence of the attribute,
243 but the code should still work. An unsupported attribute is one which is
244 ignored by the LLVM compiler, which will cause a different interpretation of
245 the program.<p>
246
247 <ol>
248 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
249 Arrays whose length is computed at run time.<br>
250 Supported, but allocated stack space is not freed until the function returns (noted above).
251
252 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
253 Declaring that functions have no side effects, or that they can never return.<br>
254 <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>,
255 <tt>warn_unused_result</tt>, <tt>weak</tt><br>
256 <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>
257 <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
258 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>, <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
259 <tt>fastcall</tt>, all other target specific attributes
260
261 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
262 Specifying attributes of variables.<br>
263 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
264 <tt>deprecated</tt>, <tt>transparent_union</tt>,
265 <tt>unused</tt>, <tt>weak</tt><br>
266 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
267 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
268 <tt>vector_size</tt>, <tt>dllimport</tt>,
269 <tt>dllexport</tt>, all target specific attributes.<br>
270
271 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.
272 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
273 <tt>deprecated</tt>, <tt>may_alias</tt>
274 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>
275 all target specific attributes.<br>
276 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
277 Other built-in functions.<br>
278 We support all builtins which have a C language equivalent (e.g.,
279 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
280 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
281 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt> (ignored).
282 </ol><p>
283
284
285 The following extensions <b>are</b> known to be supported:
286 <ol>
287 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.
288 <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]289 <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]290 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.
291 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.
292 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.
293 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.
294 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.
295 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.
296 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variadic-Macros.html#Variadic%20Macros">Variadic Macros</a>: Macros with a variable number of arguments.
297 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.
298 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Subscripting.html#Subscripting">Subscripting</a>: Any array can be subscripted, even if not an lvalue.
299 <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.
300 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.
301 <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.
302 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.
303
304 <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.
305 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.
306 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.
307
308 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.
309 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized.
310 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.
311 <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;.
312 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.
313 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).
314 <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.
315 <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.
316 <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.
317 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html#Unnamed%20Fields">Unnamed Fields</a>: Unnamed struct/union fields within structs/unions.
318 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.
319 </ol><p>
320
321 If you run into GCC extensions which have not been included in any of these
322 lists, please let us know (also including whether or not they work).
323
324
325<!-- _______________________________________________________________________ -->
326</ul><h4><a name="c++-fe"><hr size=0>Known problems with the C++ front-end</h4><ul>
327
John Criswell97745952003-10-27 17:41:53 +0000[diff] [blame]328For this release, the C++ front-end is considered to be fully functional but
329of <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]330
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]331</ul><b>Bugs</b>:<ul><p>
332
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]333<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
334 front-end</a><p>
335
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]336</ul><b>Notes</b>:<ul><p>
337
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]338<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
339parser is significantly more standards compliant (and picky) than prior GCC
340versions. For more information, see the C++ section of the <a
341href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.<p>
342
343<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]344 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]345 function and in the <tt>setjmp</tt> receiver function may not be run.
346 Objects in intervening stack frames will be destroyed however (which is
347 better than most compilers).<p>
348
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]349<li>The LLVM C++ front-end follows the <a
350 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
351 This document, which is not Itanium specific, specifies a standard for name
352 mangling, class layout, v-table layout, RTTI formats, and other C++
353 representation issues. Because we use this API, code generated by the LLVM
354 compilers should be binary compatible with machine code generated by other
355 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
356 <i>However</i>, the exception handling mechanism used by LLVM is very
357 different from the model used in the Itanium ABI, so <b>exceptions will not
358 interact correctly</b> .
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]359
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]360<li><a href="http://llvm.cs.uiuc.edu/PR11">Code for executing destructors when
361 unwinding is not shared</a> (this is a quality of implementation problem,
362 which does not effect functionality).<p>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]363
364
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]365<!-- _______________________________________________________________________ -->
366</ul><h4><a name="x86-be"><hr size=0>Known problems with the X86 back-end</h4><ul>
367
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]368<li>The X86 code generator <a
Chris Lattner0d4379a2003-10-08 06:01:38 +0000[diff] [blame]369href="http://llvm.cs.uiuc.edu/PR16">does not currently
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]370support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
371or calls the C <tt>longjmp</tt> function will abort.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]372
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]373
374<!-- _______________________________________________________________________ -->
375</ul><h4><a name="sparc-be"><hr size=0>Known problems with the Sparc back-end</h4><ul>
376
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]377<li>The Sparc code generator <a
Chris Lattner0d4379a2003-10-08 06:01:38 +0000[diff] [blame]378href="http://llvm.cs.uiuc.edu/PR15">does not currently
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]379support the <tt>unwind</tt> instruction</a>, so code that throws a C++ exception
380or calls the C <tt>longjmp</tt> function will abort.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]381
382
383<!-- _______________________________________________________________________ -->
384</ul><h4><a name="c-be"><hr size=0>Known problems with the C back-end</h4><ul>
385
386<li>The C back-end produces code that violates the ANSI C Type-Based Alias
387Analysis rules. As such, special options may be necessary to compile the code
388(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
389problem probably cannot be fixed.<p>
390
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]391<li><a href="http://llvm.cs.uiuc.edu/PR33">Initializers for global variables</a>
392cannot include special floating point numbers like Not-A-Number or Infinity.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]393
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]394<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]395supported</a>. This should not affect LLVM produced by the C or C++
396frontends.<p>
397
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]398<li><a href="http://llvm.cs.uiuc.edu/PR77">Variables in scope of output setjmp
399calls should be volatile</a>. Note that this does not effect correctness on
400many platforms.<p>
401
402<li>The code produces by the C back-end has only been tested with the Sun CC,
403GCC, and Intel compilers. It is possible that it will have to be adjusted to
404support other C compilers.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]405
406
407
408<!-- *********************************************************************** -->
409</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
410<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
411<a name="additionalinfo">Additional Information
412</b></font></td></tr></table><ul>
413<!-- *********************************************************************** -->
414
415A wide variety of additional information is available on the LLVM web page,
416including mailing lists publications describing algorithms and components
417implemented in LLVM. The web page also contains versions of the API
418documentation which is up-to-date with the CVS version of the source code. You
419can access versions of these documents specific to this release by going into
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]420the "<tt>llvm/doc/</tt>" directory in the LLVM tree.<p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]421
422If you have any questions or comments about LLVM, please feel free to contact us
423via the mailing lists.<p>
424
425
426<!-- *********************************************************************** -->
427</ul>
428<!-- *********************************************************************** -->
429
430<hr><font size-1>
431
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]432Maintained By: <a href="http://llvm.cs.uiuc.edu/">The LLVM Team</a><br>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]433<!-- Created: Wed Oct 1 17:38:54 CDT 2003 -->
434<!-- hhmts start -->
Brian Gaeke78792062003-11-11 21:52:34 +0000[diff] [blame]435Last modified: Tue Nov 11 15:48:35 CST 2003
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]436<!-- hhmts end -->
437</body></html>