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Chris Lattner163c3262004-08-16 00:20:18 +00007 <title>LLVM 1.4 Release Notes</title>
Misha Brukman80731b92003-11-22 00:38:41 +00008</head>
9<body>
Chris Lattner3d482502003-10-02 04:57:28 +000010
Chris Lattner163c3262004-08-16 00:20:18 +000011<div class="doc_title">LLVM 1.4 Release Notes</div>
Chris Lattner3d482502003-10-02 04:57:28 +000012
13<ol>
Misha Brukman80731b92003-11-22 00:38:41 +000014 <li><a href="#intro">Introduction</a></li>
15 <li><a href="#whatsnew">What's New?</a></li>
Chris Lattner77a51732004-04-30 22:17:12 +000016 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +000017 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +000018 <li><a href="#knownproblems">Known Problems</a>
19 <ul>
Chris Lattner1a7e43c2004-04-01 00:41:31 +000020 <li><a href="#experimental">Experimental features included in this
21 release</a>
Chris Lattner3d482502003-10-02 04:57:28 +000022 <li><a href="#core">Known problems with the LLVM Core</a>
23 <li><a href="#c-fe">Known problems with the C Front-end</a>
24 <li><a href="#c++-fe">Known problems with the C++ Front-end</a>
25 <li><a href="#x86-be">Known problems with the X86 Back-end</a>
Misha Brukmana516e992004-07-12 16:55:41 +000026 <li><a href="#sparcv9-be">Known problems with the SparcV9 Back-end</a>
Chris Lattnerdf925ce2004-11-07 01:55:32 +000027 <li><a href="#ppc-be">Known problems with the PowerPC Back-end</a>
Chris Lattner3d482502003-10-02 04:57:28 +000028 <li><a href="#c-be">Known problems with the C back-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +000029 </ul></li>
30 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +000031</ol>
32
Chris Lattner020e1fc2004-05-23 21:07:27 +000033<div class="doc_author">
34 <p>Written by the <a href="http://llvm.cs.uiuc.edu">LLVM team</a><p>
Misha Brukman80731b92003-11-22 00:38:41 +000035</div>
Chris Lattner3d482502003-10-02 04:57:28 +000036
37<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +000038<div class="doc_section">
39 <a name="intro">Introduction</a>
40</div>
Chris Lattner3d482502003-10-02 04:57:28 +000041<!-- *********************************************************************** -->
42
Misha Brukman80731b92003-11-22 00:38:41 +000043<div class="doc_text">
44
45<p>This document contains the release notes for the LLVM compiler
Chris Lattner163c3262004-08-16 00:20:18 +000046infrastructure, release 1.4. Here we describe the status of LLVM, including any
Chris Lattnerb5bb5972004-12-07 08:04:13 +000047known problems and improvements from the previous release. The most up-to-date
Misha Brukman80731b92003-11-22 00:38:41 +000048version of this document can be found on the <a
Chris Lattner163c3262004-08-16 00:20:18 +000049href="http://llvm.cs.uiuc.edu/releases/1.4/">LLVM 1.4 web site</a>. If you are
John Criswell86a3a482003-12-18 16:43:17 +000050not reading this on the LLVM web pages, you should probably go there because
Misha Brukman80731b92003-11-22 00:38:41 +000051this document may be updated after the release.</p>
Chris Lattner62495762003-10-02 16:38:05 +000052
Chris Lattnerb5bb5972004-12-07 08:04:13 +000053<p>For more information about LLVM, including information about the latest
54release, please check out the <a href="http://llvm.cs.uiuc.edu">main LLVM
Chris Lattnere7525b52003-10-07 21:38:31 +000055web site</a>. If you have questions or comments, the <a
56href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman80731b92003-11-22 00:38:41 +000057list</a> is a good place to send them.</p>
Chris Lattner3d482502003-10-02 04:57:28 +000058
Chris Lattnere76e9ab2003-12-12 04:25:33 +000059<p>Note that if you are reading this file from CVS, this document applies
60to the <i>next</i> release, not the current one. To see the release notes for
61the current or previous releases, see the <a
Misha Brukman80731b92003-11-22 00:38:41 +000062href="http://llvm.cs.uiuc.edu/releases/">releases page</a>.</p>
63
64</div>
Chris Lattner3d482502003-10-02 04:57:28 +000065
66<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +000067<div class="doc_section">
68 <a name="whatsnew">What's New?</a>
69</div>
Chris Lattner3d482502003-10-02 04:57:28 +000070<!-- *********************************************************************** -->
71
Misha Brukman80731b92003-11-22 00:38:41 +000072<div class="doc_text">
73
Chris Lattner163c3262004-08-16 00:20:18 +000074<p>This is the fifth public release of the LLVM compiler infrastructure.</p>
Chris Lattnerba7bd472003-12-06 20:22:41 +000075
Chris Lattnerb5bb5972004-12-07 08:04:13 +000076<p> At this time, LLVM is known to correctly compile and a broad range of
77C and C++ programs, including the SPEC CPU95 &amp; 2000 suite. This release
78includes several major enhancements to the LLVM system, including a new
79PowerPC JIT, enhancements to the C/C++ front-end to provide source line number
80information in LLVM, a new <a href="CommandGuide/html/llvmc.html">compiler
81driver</a>, and several other enhancements listed below. It also includes
82bug fixes for those problems found since the 1.3 release.</p>
83
84<p>Note that this release seperates the LLVM Program Testsuite out of the
85main LLVM distribution into a seperate CVS repository and tarball. This
86reduces the size of the main LLVM distribution. Also note that LLVM now
87builds tools into llvm/Debug/bin by default instead of llvm/tools/Debug.</p>
Chris Lattnerba7bd472003-12-06 20:22:41 +000088
Chris Lattner21a90402004-05-24 04:50:25 +000089</div>
90
Chris Lattnerba7bd472003-12-06 20:22:41 +000091<!--=========================================================================-->
92<div class="doc_subsubsection">
Chris Lattner8ebf2532004-02-25 16:36:51 +000093<a name="newfeatures">This release implements the following new features:</a>
Chris Lattnerba7bd472003-12-06 20:22:41 +000094</div>
Chris Lattnere7525b52003-10-07 21:38:31 +000095
Chris Lattner21a90402004-05-24 04:50:25 +000096<div class="doc_text">
Chris Lattnere7525b52003-10-07 21:38:31 +000097<ol>
Chris Lattnerb5bb5972004-12-07 08:04:13 +000098 <li>LLVM now includes a Just-In-Time compiler for the PowerPC target.</li>
99 <li>llvmgcc and llvmg++ now emit source line number information when '-g' is
100 passed in. This information can be used with llvm-db or other tools and
101 passes.</li>
102 <li>The test/Programs hierarchy <a href="http://llvm.cs.uiuc.edu/PR257">has
103 been moved out of the main LLVM tree</a> into a separate CVS repository and
104 tarball. This shrinks the distribution size of LLVM itself significantly.
Reid Spencere4190fa2004-11-18 18:38:58 +0000105 </li>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000106 <li>LLVM now optimizes global variables more aggressively than it did
107 before.</li>
Reid Spencer493d9c22004-11-25 22:38:30 +0000108 <li>LLVM now includes the new '<tt>undef</tt>' value and
109 <a href="LangRef.html#i_unreachable"><tt>unreachable</tt></a> instruction,
110 which give the optimizer more information about the behavior of the
111 program.
112 </li>
Reid Spencer493d9c22004-11-25 22:38:30 +0000113 <li>Bytecode compression with bzip2 has been implemented. All bytecode files
114 generated by LLVM will now be compressed by default. Compression can be
115 disabled with the <tt>-disable-compression</tt> option to the tools that can
116 generate bytecode files.
117 </li>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000118 <li>A generic <a href="CommandGuide/html/llvmc.html">compiler driver</a>
119 (llvmc) and
120 an associated <a href="CommandGuide/html/llvm-ld.html">generic linker</a>
121 (llvm-ld) have been added. The compiler driver is generic because it can be
122 configured
Reid Spencer493d9c22004-11-25 22:38:30 +0000123 to pre-process, translate, optimize, assemble, and link code from any source
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000124 language with an LLVM front-end. This makes it easier for compiler writers
125 to hide the multiple steps required to compile a program (compiling,
126 optimizing, linking runtime libraries, etc) in one simple command.
Reid Spencer493d9c22004-11-25 22:38:30 +0000127 </li>
128 <li>The <a href="http://llvm.cs.uiuc.edu/PR263">dependent libraries</a>
129 feature has been implemented. This allows front end compilers to indicate in
130 the bytecode which libraries the bytecode needs to be linked with. Both the
131 C/C++ front end and Stacker support generating the required libraries. The
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000132 linker now supports using this information to ensure required libaries are
Reid Spencer493d9c22004-11-25 22:38:30 +0000133 linked into the module. This minimizes the need to use the <tt>-l</tt> option
134 when using <a href="CommandGuide/html/llvmc.html"><tt>llvmc</tt></a>
135 </li>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000136 <li>The LLVM makefiles have been improved to build LLVM much faster and
137 includes new targets (like dist-check, uninstall). One important user-visible
138 change is that libraries and tools will now be built into
139 <tt>$builddir/Debug/{bin,lib}</tt>
140 instead of <tt>$builddir/tools/Debug</tt> and <tt>$builddir/lib/Debug</tt>
141 (Similarly for <tt>Release</tt> and <tt>Profile</tt> builds).
Reid Spencere4190fa2004-11-18 18:38:58 +0000142 </li>
Chris Lattnerd5f52882004-11-17 18:19:32 +0000143 <li>The LLVM source code is much more compatible with Microsoft Visual C++,
Reid Spencer493d9c22004-11-25 22:38:30 +0000144 including the JIT and runtime-code generation, though the entire system
145 may not work with it.
146 </li>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000147 <li>The JIT-Target interfaces <a href="http://llvm.cs.uiuc.edu/PR283">are
Reid Spencer493d9c22004-11-25 22:38:30 +0000148 now much simpler</a> and more powerful.
149 </li>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000150 <li>LLVM now provides llvm-ar and llvm-ranlib tools for working with archives
151 of LLVM bytecode files.</li>
Chris Lattnere0267142004-11-27 19:24:06 +0000152 <li>zlib and libpng are <a href="http://llvm.cs.uiuc.edu/PR417">no longer
153 included in the main LLVM tarball</a>.</li>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000154 <li>The LLVM code generator now automatically generates assembly code writers
155 from an abstract target descriptions, eliminating the need to write
156 assembly printers manually.</li>
Chris Lattner4d09fff2004-11-27 21:29:43 +0000157 <li>LLVM regression and feature tests can now be run with DejaGNU.</li>
Chris Lattner9812dbc2004-12-01 17:10:36 +0000158 <li>llvmgcc and llvmg++ now emit source-level line number information, making
159 it possible to map from LLVM code back to source. This is currently used
160 by llvm-db.</li>
Chris Lattner592db402003-11-19 22:05:38 +0000161</ol>
Chris Lattner4491de62003-11-08 04:28:55 +0000162
Chris Lattner21a90402004-05-24 04:50:25 +0000163</div>
164
Chris Lattnerba7bd472003-12-06 20:22:41 +0000165
166<!--=========================================================================-->
167<div class="doc_subsubsection">
168In this release, the following missing features were implemented:
169</div>
Chris Lattner4491de62003-11-08 04:28:55 +0000170
Chris Lattner21a90402004-05-24 04:50:25 +0000171<div class="doc_text">
172
Chris Lattner4491de62003-11-08 04:28:55 +0000173<ol>
Reid Spencere4190fa2004-11-18 18:38:58 +0000174 <li><a href="http://llvm.cs.uiuc.edu/PR419">JIT interface should support
Reid Spencer493d9c22004-11-25 22:38:30 +0000175 arbitrary calls</a>
176 </li>
Reid Spencere4190fa2004-11-18 18:38:58 +0000177 <li>The <tt>llvm-ar</tt> tool was previously incomplete and didn't properly
178 support other ar(1) implementations. This has been corrected. <tt>llvm-ar</tt>
179 now fully supports all archive editing functions, table of contents listing,
180 extraction, and printing. It can also read BSD4.4/MacOSX and SVR4 style
Reid Spencer493d9c22004-11-25 22:38:30 +0000181 archives. See <a href="CommandGuide/html/llvm-ar.html">llvm-ar</a> for
182 details.
183 </li>
Misha Brukman80731b92003-11-22 00:38:41 +0000184</ol>
Chris Lattnere7525b52003-10-07 21:38:31 +0000185
Chris Lattner21a90402004-05-24 04:50:25 +0000186</div>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000187
188<!--=========================================================================-->
189<div class="doc_subsubsection">
Misha Brukman017f2f32004-04-19 02:56:49 +0000190<a name="qualityofimp">In this release, the following Quality of Implementation
191issues were fixed:</a>
Chris Lattner4df78f02003-12-20 03:42:11 +0000192</div>
193
Chris Lattner21a90402004-05-24 04:50:25 +0000194<div class="doc_text">
195
Chris Lattner4df78f02003-12-20 03:42:11 +0000196<ol>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000197 <li>The linker no longer <a href="http://llvm.cs.uiuc.edu/PR426">emits many
198 useless warnings</a> when linking C++ programs.</a>
Reid Spencer2ea21002004-12-06 22:32:33 +0000199 </li>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000200 <li>The LLVM <a href="http://llvm.cs.uiuc.edu/PR352">#include namespace</a>
201 has been made consistent. Files in <tt>llvm/include/{Support,Config}</tt>
202 are now located in <tt>llvm/include/llvm/{Support,Config}</tt>.</a>
Reid Spencer493d9c22004-11-25 22:38:30 +0000203 </li>
Reid Spencerb4e3ec82004-11-22 18:40:51 +0000204 <li>The names of the libraries generated by compiling LLVM source have been
205 changed to ensure they do not conflict with other packages upon installation.
206 Each LLVM library is now prefixed with LLVM and uses mixed clase. For example,
207 the library <tt>libasmparser.a</tt> in 1.3 has become
Reid Spencer493d9c22004-11-25 22:38:30 +0000208 <tt>libLLVMAsmParser.a</tt> in release 1.4.
209 </li>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000210 <li>The C++ frontend no longer expands and emits <a
211 href="http://llvm.cs.uiuc.edu/PR459">all inline functions, even if they
212 are unused</a>. It now properly tracks which functions are needed and
213 only compiles those.</li>
Chris Lattner4df78f02003-12-20 03:42:11 +0000214
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000215 <li>Many improvements in the <a href="http://llvm.cs.uiuc.edu/PR256">autoconf
216 and makefile systems</a> have been implemented.</li>
Brian Gaeke8b05e4f2004-01-16 21:55:04 +0000217</ol>
Chris Lattner21a90402004-05-24 04:50:25 +0000218</div>
Brian Gaeke8b05e4f2004-01-16 21:55:04 +0000219
220<!--=========================================================================-->
221<div class="doc_subsubsection">
Chris Lattner2ad48782004-05-02 04:19:15 +0000222<a name="codequality">This release includes the following Code Quality
223improvements:</a>
Chris Lattner23257062004-05-23 20:42:08 +0000224</div>
Chris Lattner639579c2003-10-27 17:06:39 +0000225
Chris Lattner21a90402004-05-24 04:50:25 +0000226<div class="doc_text">
Chris Lattner639579c2003-10-27 17:06:39 +0000227<ol>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000228 <li>The optimizer produces <a href="http://llvm.cs.uiuc.edu/PR362">more
229 efficient code for std::min/std::max</a> and other similar functions.</li>
230 <li>The X86 backend generates substantially faster code for floating point
231 intensive programs.</li>
232 <li>The PowerPC backend generates more efficient code in many common
233 scenarios.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000234</ol>
Reid Spencer3e58f582004-05-23 17:23:13 +0000235</div>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000236
237<!--=========================================================================-->
238<div class="doc_subsubsection">
Misha Brukman017f2f32004-04-19 02:56:49 +0000239<a name="bugfix">In this release, the following bugs in the previous release
240were fixed:</a>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000241</div>
242
Chris Lattner21a90402004-05-24 04:50:25 +0000243<div class="doc_text">
244
Chris Lattner5cd40922004-08-02 20:28:44 +0000245<p>Bugs fixed in the LLVM Core:</p>
Chris Lattnere7525b52003-10-07 21:38:31 +0000246
247<ol>
Reid Spencer493d9c22004-11-25 22:38:30 +0000248 <li><a href="http://llvm.cs.uiuc.edu/PR420">[licm] LICM invalidates alias
249 analysis info and uses broken information</a> (optimizer crash)</li>
250 <li><a href="http://llvm.cs.uiuc.edu/PR422">[asmwriter] Asmwriter is really
251 slow for functions with lots of values</a></li>
252 <li><a href="http://llvm.cs.uiuc.edu/PR423">[anders-aa] Andersen's AA is
253 completely broken in LLVM 1.3</a></li>
254 <li><a href="http://llvm.cs.uiuc.edu/PR430">[bcwriter] Empty compaction
255 tables defined</a></li>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000256 <li><a href="http://llvm.cs.uiuc.edu/PR227">[X86] llc output for functions
257 w/certain names tickles GNU 'as' bugs</a></li>
Chris Lattnerb3d140d2004-12-03 17:21:33 +0000258 <li><a href="http://llvm.cs.uiuc.edu/PR472">[cbackend] Static globals are
259 prototyped as 'extern'</a></li>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000260</ol>
261
Chris Lattnerba7bd472003-12-06 20:22:41 +0000262<p>Bugs in the C/C++ front-end:</p>
263
264<ol>
Reid Spencer493d9c22004-11-25 22:38:30 +0000265 <li><a href="http://llvm.cs.uiuc.edu/PR445">[llvmg++] not enough templates are
266 instantiated</a></li>
267 <li><a href="http://llvm.cs.uiuc.edu/PR450">[llvmg++] Extern const globals
268 cannot be marked 'constant' if they have nontrivial ctors or dtors</a></li>
269 <li><a href="http://llvm.cs.uiuc.edu/PR461">[llvmgcc] Crash compiling unnamed
Chris Lattner6345ee292004-11-25 06:31:42 +0000270 bitfield which does not increase struct size</a></li>
Chris Lattnerb3d2ade2004-11-27 19:50:58 +0000271 <li><a href="http://llvm.cs.uiuc.edu/PR424">[llvmgcc] llvmgcc emits invalid
272 constant exprs</a></li>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000273 <li><a href="http://llvm.cs.uiuc.edu/PR421">[llvmg++] Crash initializing
Chris Lattnerdcc15992004-11-27 22:47:08 +0000274 array with constructors in hard EH situations</a></li>
Chris Lattner83c17802004-11-27 23:27:26 +0000275 <li><a href="http://llvm.cs.uiuc.edu/PR397">[llvm-gcc] Inline function
276 redefinitions error due to 'asm' function rename</a></li>
Chris Lattnerc1f5d472004-11-28 00:43:59 +0000277 <li><a href="http://llvm.cs.uiuc.edu/PR244">[llvm-gcc] Error when an
Chris Lattnerd997b022004-11-28 00:09:38 +0000278 implicitly external function is re-declared as static</a></li>
Chris Lattnerc1f5d472004-11-28 00:43:59 +0000279 <li><a href="http://llvm.cs.uiuc.edu/PR360">[llvmgcc] Structure field with
280 non-constant offset crashes llvmgcc</a></li>
Chris Lattnere8d482e2004-11-28 01:25:20 +0000281 <li><a href="http://llvm.cs.uiuc.edu/PR447">[llvmg++] Crash compiling
282 friend with default argument</a></li>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000283</ol>
Brian Gaeke730d8d62004-08-24 07:43:48 +0000284
285<p>Bugs fixed in the Sparc V9 back-end:</p>
286
287<ol>
Reid Spencer493d9c22004-11-25 22:38:30 +0000288 <li><a href="http://llvm.cs.uiuc.edu/PR428">[sparcv9] regalloc assertion
Brian Gaeke730d8d62004-08-24 07:43:48 +0000289 failure with certain indirect calls</a></li>
290</ol>
291
Chris Lattner21a90402004-05-24 04:50:25 +0000292</div>
Reid Spencer3e58f582004-05-23 17:23:13 +0000293
Chris Lattner62495762003-10-02 16:38:05 +0000294<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000295<div class="doc_section">
296 <a name="portability">Portability and Supported Platforms</a>
297</div>
Chris Lattner62495762003-10-02 16:38:05 +0000298<!-- *********************************************************************** -->
299
Misha Brukman80731b92003-11-22 00:38:41 +0000300<div class="doc_text">
301
Chris Lattner2c7b0872004-06-01 18:22:41 +0000302<p>LLVM is known to work in the following platforms:</p>
303
304<ul>
305<li>Intel and AMD machines running Red Hat Linux and FreeBSD (and probably
306 other unix-like systems).</li>
307<li>Sun UltraSPARC workstations running Solaris 8.</li>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000308<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
309 support is available for native builds with Visual C++).</li>
310<li>PowerPC-based Mac OS X systems, running 10.2 and above.</li>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000311</ul>
312
Brian Gaekee3e557e2004-05-09 05:28:35 +0000313<p>The core LLVM infrastructure uses
314<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
315to the machine and operating system on which it is built. However, minor
316porting may be required to get LLVM to work on new platforms. We welcome your
317portability patches and reports of successful builds or error messages.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000318
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000319<!--
Chris Lattner2c7b0872004-06-01 18:22:41 +0000320<p>Note that the LLVM build system does not currently support directories with
321spaces on them when running on Win32/cygwin. We strongly recommend running
322LLVM and the C frontend out of a top-level directory without spaces (e.g.,
Chris Lattnerce1a3842004-06-01 19:41:30 +0000323<tt>/cygdrive/c/llvm</tt>). Also, make sure to install <b>all</b> of the
324cygwin packages. By default, many important tools are not installed that
Chris Lattnera752fce2004-08-16 20:20:46 +0000325are needed by the LLVM build process or test suite (e.g., /bin/time). Finally,
326please make sure that there are no directories with spaces in them in your
327PATH environment variable.</p>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000328-->
Chris Lattner2c7b0872004-06-01 18:22:41 +0000329
Misha Brukman80731b92003-11-22 00:38:41 +0000330</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000331
332<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000333<div class="doc_section">
334 <a name="knownproblems">Known Problems</a>
335</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000336<!-- *********************************************************************** -->
337
Misha Brukman80731b92003-11-22 00:38:41 +0000338<div class="doc_text">
339
340<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner3d482502003-10-02 04:57:28 +0000341component. As new problems are discovered, they will be added to these
Chris Lattnerb84f3322003-12-12 21:22:16 +0000342sections. If you run into a problem, please check the <a
John Criswell86a3a482003-12-18 16:43:17 +0000343href="http://llvm.cs.uiuc.edu/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000344there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000345
Misha Brukman80731b92003-11-22 00:38:41 +0000346</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000347
Chris Lattnerb911de42004-03-14 02:03:02 +0000348<!-- ======================================================================= -->
349<div class="doc_subsection">
350 <a name="experimental">Experimental features included with this release</a>
351</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000352
Chris Lattnerb911de42004-03-14 02:03:02 +0000353<div class="doc_text">
354
Misha Brukmanfa50a222004-05-12 21:46:05 +0000355<p>The following components of this LLVM release are either untested, known to
356be broken or unreliable, or are in early development. These components should
357not be relied on, and bugs should not be filed against them, but they may be
358useful to some people. In particular, if you would like to work on one of these
359components, please contact us on the llvmdev list.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000360
361<ul>
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000362<li>The following passes are incomplete or buggy, and may be removed in future
363 releases: <tt>-pgmdep, -memdep, -ipmodref, -cee, -branch-combine,
364 -instloops, -paths, -pre</tt></li>
365<li>The <tt>llvm-db</tt> tool is in a very early stage of development, but can
366 be used to step through programs and inspect the stack.</li>
Chris Lattnerfa835102004-12-02 17:20:17 +0000367<li>The "iterative scan" register allocator (enabled with -regalloc=iterativescan)
368 is not stable.</li>
Chris Lattnerb911de42004-03-14 02:03:02 +0000369</ul>
370
371</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000372
Misha Brukman80731b92003-11-22 00:38:41 +0000373<!-- ======================================================================= -->
374<div class="doc_subsection">
375 <a name="core">Known problems with the LLVM Core</a>
376</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000377
Misha Brukman80731b92003-11-22 00:38:41 +0000378<div class="doc_text">
379
380<ul>
Reid Spencer493d9c22004-11-25 22:38:30 +0000381 <li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not work.
382 </li>
383 <li>The JIT does not use mutexes to protect its internal data structures. As
384 such, execution of a threaded program could cause these data structures to be
385 corrupted.
386 </li>
Reid Spencer493d9c22004-11-25 22:38:30 +0000387 <li><a href="http://llvm.cs.uiuc.edu/PR240">The lower-invoke pass does not
388 mark values live across a setjmp as volatile</a>. This missing feature
389 only affects targets whose setjmp/longjmp libraries do not save and restore
390 the entire register file.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000391</ul>
Misha Brukman80731b92003-11-22 00:38:41 +0000392</div>
393
394<!-- ======================================================================= -->
395<div class="doc_subsection">
396 <a name="c-fe">Known problems with the C front-end</a>
397</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000398
Chris Lattner3d482502003-10-02 04:57:28 +0000399<!-- _______________________________________________________________________ -->
Chris Lattner5a8a7282003-12-14 05:03:43 +0000400<div class="doc_subsubsection">Bugs</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000401
Misha Brukman80731b92003-11-22 00:38:41 +0000402<div class="doc_text">
Misha Brukman80731b92003-11-22 00:38:41 +0000403<ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000404<li>C99 Variable sized arrays do not release stack memory when they go out of
405 scope. Thus, the following program may run out of stack space:
406<pre>
407 for (i = 0; i != 1000000; ++i) {
408 int X[n];
409 foo(X);
410 }
Misha Brukman80731b92003-11-22 00:38:41 +0000411</pre></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000412
Misha Brukmanfa50a222004-05-12 21:46:05 +0000413<li>Initialization of global union variables can only be done <a
Misha Brukman68ef9a92004-12-04 00:45:09 +0000414href="http://llvm.cs.uiuc.edu/PR162">with the largest union member</a>.</li>
Chris Lattner1ab58dd2004-03-16 21:39:04 +0000415
John Criswell86a3a482003-12-18 16:43:17 +0000416</ul>
Misha Brukman80731b92003-11-22 00:38:41 +0000417</div>
418
419<!-- _______________________________________________________________________ -->
420<div class="doc_subsubsection">
421 Notes
422</div>
423
424<div class="doc_text">
425
426<ul>
427
428<li>Inline assembly is not yet supported.</li>
Chris Lattnerd2a74272003-10-27 18:30:37 +0000429
430<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman80731b92003-11-22 00:38:41 +0000431support for floating point data types of any size other than 32 and 64
432bits.</li>
433
434<li>The following Unix system functionality has not been tested and may not
435work:
Misha Brukman7cb4e382003-11-22 01:00:11 +0000436 <ol>
437 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
438 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
439 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
440 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
441 - These functions have not been tested.
442 </ol></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000443
444<li>Although many GCC extensions are supported, some are not. In particular,
445 the following extensions are known to <b>not be</b> supported:
446 <ol>
Misha Brukman80731b92003-11-22 00:38:41 +0000447 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000448 <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.</li>
449 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
450 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html#Extended%20Asm">Extended Asm</a>: Assembler instructions with C expressions as operands.</li>
John Criswell86a3a482003-12-18 16:43:17 +0000451 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000452 <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.</li>
453 <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.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000454 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions.</li>
455 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.</li>
456 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables.</li>
457 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
Misha Brukman7cb4e382003-11-22 01:00:11 +0000458 </ol>
Chris Lattner3d482502003-10-02 04:57:28 +0000459
Misha Brukman80731b92003-11-22 00:38:41 +0000460 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner3d482502003-10-02 04:57:28 +0000461 attribute means that the LLVM compiler ignores the presence of the attribute,
462 but the code should still work. An unsupported attribute is one which is
John Criswell86a3a482003-12-18 16:43:17 +0000463 ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman80731b92003-11-22 00:38:41 +0000464 the program.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000465
466 <ol>
467 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
468 Arrays whose length is computed at run time.<br>
Misha Brukman80731b92003-11-22 00:38:41 +0000469 Supported, but allocated stack space is not freed until the function returns (noted above).</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000470
471 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Misha Brukman80731b92003-11-22 00:38:41 +0000472
John Criswell86a3a482003-12-18 16:43:17 +0000473 Declaring that functions have no side effects or that they can never
Misha Brukman80731b92003-11-22 00:38:41 +0000474 return.<br>
475
476 <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
477 <tt>constructor</tt>, <tt>destructor</tt>, <tt>unused</tt>,
478 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
479
480 <b>Ignored:</b> <tt>noreturn</tt>, <tt>noinline</tt>,
481 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
482 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
483
484 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>,
485 <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
486 <tt>fastcall</tt>, all other target specific attributes</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000487
488 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
489 Specifying attributes of variables.<br>
490 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
491 <tt>deprecated</tt>, <tt>transparent_union</tt>,
492 <tt>unused</tt>, <tt>weak</tt><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000493
Chris Lattner3d482502003-10-02 04:57:28 +0000494 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
495 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
496 <tt>vector_size</tt>, <tt>dllimport</tt>,
Misha Brukman80731b92003-11-22 00:38:41 +0000497 <tt>dllexport</tt>, all target specific attributes.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000498
Misha Brukman8395d732003-12-12 04:37:31 +0000499 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.<br>
Chris Lattner3d482502003-10-02 04:57:28 +0000500 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukman8395d732003-12-12 04:37:31 +0000501 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000502
503 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
504 all target specific attributes.</li>
505
Chris Lattner3d482502003-10-02 04:57:28 +0000506 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
507 Other built-in functions.<br>
508 We support all builtins which have a C language equivalent (e.g.,
509 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
510 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Chris Lattnerb7c4bac2004-06-18 06:26:29 +0000511 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
512 (currently ignored). We also support builtins for ISO C99 floating
513 point comparison macros (e.g., <tt>__builtin_islessequal</tt>).</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000514 </ol>
Chris Lattner3d482502003-10-02 04:57:28 +0000515
Misha Brukman80731b92003-11-22 00:38:41 +0000516 <p>The following extensions <b>are</b> known to be supported:</p>
517
Chris Lattner3d482502003-10-02 04:57:28 +0000518 <ol>
Chris Lattnerd3dc8502004-03-16 08:54:07 +0000519 <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.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000520 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
521 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Typeof.html#Typeof">Typeof</a>: <code>typeof</code>: referring to the type of an expression.</li>
Tanya Lattnerce33a1b2004-06-22 03:48:17 +0000522 <li><a href="http://gcc.gnu.org/onlinedocs/gcc-3.4.0/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000523 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
524 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
525 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
526 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
527 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
528 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
529 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variadic-Macros.html#Variadic%20Macros">Variadic Macros</a>: Macros with a variable number of arguments.</li>
530 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
531 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Subscripting.html#Subscripting">Subscripting</a>: Any array can be subscripted, even if not an lvalue.</li>
Misha Brukman8395d732003-12-12 04:37:31 +0000532 <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.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000533 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
John Criswell86a3a482003-12-18 16:43:17 +0000534 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
535or arrays as values.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000536 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.</li>
Misha Brukman8395d732003-12-12 04:37:31 +0000537 <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.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000538 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
539 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
540 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
541 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized.</li>
542 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
543 <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;.</li>
544 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
545 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
546 <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.</li>
547 <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.</li>
548 <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.</li>
Chris Lattner3646dad2004-02-14 04:08:29 +0000549 <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.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000550 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Unnamed-Fields.html#Unnamed%20Fields">Unnamed Fields</a>: Unnamed struct/union fields within structs/unions.</li>
551 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.</li>
Misha Brukman7cb4e382003-11-22 01:00:11 +0000552 </ol></li>
553
554</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000555
Misha Brukman80731b92003-11-22 00:38:41 +0000556<p>If you run into GCC extensions which have not been included in any of these
557lists, please let us know (also including whether or not they work).</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000558
Misha Brukman80731b92003-11-22 00:38:41 +0000559</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000560
Misha Brukman80731b92003-11-22 00:38:41 +0000561<!-- ======================================================================= -->
562<div class="doc_subsection">
563 <a name="c++-fe">Known problems with the C++ front-end</a>
564</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000565
Misha Brukman80731b92003-11-22 00:38:41 +0000566<div class="doc_text">
567
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000568<p>For this release, the C++ front-end is considered to be fully. It has been
569tested and works for a number of non-trivial programs, including LLVM
570itself.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000571
572</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000573
574<!-- _______________________________________________________________________ -->
Chris Lattner141ebb62004-02-14 04:12:41 +0000575<div class="doc_subsubsection">Bugs</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000576
Misha Brukman80731b92003-11-22 00:38:41 +0000577<div class="doc_text">
Chris Lattner3d482502003-10-02 04:57:28 +0000578
Misha Brukman80731b92003-11-22 00:38:41 +0000579<ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000580<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
John Criswell86a3a482003-12-18 16:43:17 +0000581 front-end</a>.</li>
Chris Lattner041e6c92004-07-17 02:04:41 +0000582
Chris Lattner5cd40922004-08-02 20:28:44 +0000583<li><b>IA-64 specific</b>: The C++ front-end does not use <a
584href="http://llvm.cs.uiuc.edu/PR406">IA64 ABI compliant layout of v-tables</a>.
Chris Lattner041e6c92004-07-17 02:04:41 +0000585In particular, it just stores function pointers instead of function
586descriptors in the vtable. This bug prevents mixing C++ code compiled with
Chris Lattner2fd93492004-08-02 20:29:51 +0000587LLVM with C++ objects compiled by other C++ compilers.</li>
Chris Lattner041e6c92004-07-17 02:04:41 +0000588
Chris Lattner5cd40922004-08-02 20:28:44 +0000589</ul>
590
Misha Brukman80731b92003-11-22 00:38:41 +0000591</div>
592
593<!-- _______________________________________________________________________ -->
594<div class="doc_subsubsection">
595 Notes
596</div>
597
598<div class="doc_text">
599
600<ul>
Chris Lattnerd2a74272003-10-27 18:30:37 +0000601
Chris Lattner3d482502003-10-02 04:57:28 +0000602<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
603parser is significantly more standards compliant (and picky) than prior GCC
604versions. For more information, see the C++ section of the <a
Chris Lattnere76e9ab2003-12-12 04:25:33 +0000605href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000606
607<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
Chris Lattner62495762003-10-02 16:38:05 +0000608 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner3d482502003-10-02 04:57:28 +0000609 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswell86a3a482003-12-18 16:43:17 +0000610 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman80731b92003-11-22 00:38:41 +0000611 better than most compilers).</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000612
Chris Lattner62495762003-10-02 16:38:05 +0000613<li>The LLVM C++ front-end follows the <a
614 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
615 This document, which is not Itanium specific, specifies a standard for name
616 mangling, class layout, v-table layout, RTTI formats, and other C++
617 representation issues. Because we use this API, code generated by the LLVM
618 compilers should be binary compatible with machine code generated by other
619 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
620 <i>However</i>, the exception handling mechanism used by LLVM is very
621 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman80731b92003-11-22 00:38:41 +0000622 interact correctly</b>. </li>
Chris Lattner3d482502003-10-02 04:57:28 +0000623
Misha Brukman80731b92003-11-22 00:38:41 +0000624</ul>
Chris Lattner46ecf612003-10-07 22:14:37 +0000625
Misha Brukman80731b92003-11-22 00:38:41 +0000626</div>
627
628<!-- ======================================================================= -->
629<div class="doc_subsection">
630 <a name="x86-be">Known problems with the X86 back-end</a>
631</div>
632
633<div class="doc_text">
634
635<ul>
Chris Lattner5cd40922004-08-02 20:28:44 +0000636 <li>none yet</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000637</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000638
Misha Brukman80731b92003-11-22 00:38:41 +0000639</div>
640
641<!-- ======================================================================= -->
642<div class="doc_subsection">
Misha Brukmana516e992004-07-12 16:55:41 +0000643 <a name="sparcv9-be">Known problems with the SparcV9 back-end</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000644</div>
645
646<div class="doc_text">
647
648<ul>
Misha Brukmana516e992004-07-12 16:55:41 +0000649<li><a href="http://llvm.cs.uiuc.edu/PR60">[sparcv9] SparcV9 backend miscompiles
650several programs in the LLVM test suite</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000651</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000652
Misha Brukman80731b92003-11-22 00:38:41 +0000653</div>
654
655<!-- ======================================================================= -->
656<div class="doc_subsection">
Chris Lattnerdf925ce2004-11-07 01:55:32 +0000657 <a name="ppc-be">Known problems with the PowerPC back-end</a>
658</div>
659
660<div class="doc_text">
661
662<ul>
663<li>none yet</li>
664</ul>
665
666</div>
667
668<!-- ======================================================================= -->
669<div class="doc_subsection">
Misha Brukman80731b92003-11-22 00:38:41 +0000670 <a name="c-be">Known problems with the C back-end</a>
671</div>
672
673<div class="doc_text">
674
675<ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000676
677<li>The C back-end produces code that violates the ANSI C Type-Based Alias
678Analysis rules. As such, special options may be necessary to compile the code
679(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
Misha Brukman80731b92003-11-22 00:38:41 +0000680problem probably cannot be fixed.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000681
Chris Lattnerc679fbb2003-11-04 20:06:53 +0000682<li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
Chris Lattnerb28c3282003-10-24 04:03:19 +0000683supported</a>. This should not affect LLVM produced by the C or C++
Misha Brukman80731b92003-11-22 00:38:41 +0000684frontends.</li>
Chris Lattnerb28c3282003-10-24 04:03:19 +0000685
Misha Brukman80731b92003-11-22 00:38:41 +0000686</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000687
Misha Brukman80731b92003-11-22 00:38:41 +0000688</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000689
690<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000691<div class="doc_section">
692 <a name="additionalinfo">Additional Information</a>
693</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000694<!-- *********************************************************************** -->
695
Misha Brukman80731b92003-11-22 00:38:41 +0000696<div class="doc_text">
697
698<p>A wide variety of additional information is available on the LLVM web page,
John Criswell86a3a482003-12-18 16:43:17 +0000699including mailing lists and publications describing algorithms and components
Chris Lattner3d482502003-10-02 04:57:28 +0000700implemented in LLVM. The web page also contains versions of the API
701documentation which is up-to-date with the CVS version of the source code. You
702can access versions of these documents specific to this release by going into
Misha Brukman80731b92003-11-22 00:38:41 +0000703the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000704
Misha Brukman80731b92003-11-22 00:38:41 +0000705<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerb84f3322003-12-12 21:22:16 +0000706us via the <a href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">mailing
707lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000708
Misha Brukman80731b92003-11-22 00:38:41 +0000709</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000710
711<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000712
Misha Brukman80731b92003-11-22 00:38:41 +0000713<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000714<address>
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719
Misha Brukman7cb4e382003-11-22 01:00:11 +0000720 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000721 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000722</address>
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