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Reid Spencer6454ed32004-11-18 18:38:58 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]7 <title>LLVM 1.8 Release Notes</title>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]8</head>
9<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]10
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]11<div class="doc_title">LLVM 1.8 Release Notes</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]12
13<ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]14 <li><a href="#intro">Introduction</a></li>
15 <li><a href="#whatsnew">What's New?</a></li>
Chris Lattner4b538b92004-04-30 22:17:12 +0000[diff] [blame]16 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]18 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]19 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]20</ol>
21
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]22<div class="doc_author">
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]23 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]24</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]25
26<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]27<div class="doc_section">
28 <a name="intro">Introduction</a>
29</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]30<!-- *********************************************************************** -->
31
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]32<div class="doc_text">
33
34<p>This document contains the release notes for the LLVM compiler
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]35infrastructure, release 1.8. Here we describe the status of LLVM, including any
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]36known problems and major improvements from the previous release. The most
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]37up-to-date version of this document (corresponding to LLVM CVS) can be found
38on the <a
Chris Lattnerc30c5c72005-11-08 21:29:17 +0000[diff] [blame]39href="http://llvm.org/releases/">LLVM releases web site</a>. If you are
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]40not reading this on the LLVM web pages, you should probably go there because
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]41this document may be updated after the release.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]42
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]43<p>For more information about LLVM, including information about the latest
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]44release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]45web site</a>. If you have questions or comments, the <a
46href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]47list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]48
Chris Lattner78bf32b2004-12-09 22:22:58 +0000[diff] [blame]49<p>Note that if you are reading this file from CVS or the main LLVM web page,
50this document applies to the <i>next</i> release, not the current one. To see
51the release notes for the current or previous releases, see the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]52href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]53
54</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]55
56<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]57<div class="doc_section">
58 <a name="whatsnew">What's New?</a>
59</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]60<!-- *********************************************************************** -->
61
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]62<div class="doc_text">
63
Chris Lattner49e693e2006-08-09 04:08:52 +0000[diff] [blame]64<p>This is the nineth public release of the LLVM Compiler Infrastructure. This
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]65release incorporates a large number of enhancements and new features,
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]66including DWARF debugging support (C and C++ on Darwin/PPC), improved inline
67assembly support, a new <a href="http://llvm.org/nightlytest/">nightly
Chris Lattner49e693e2006-08-09 04:08:52 +0000[diff] [blame]68tester</a>, llvm-config enhancements, many bugs
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]69fixed, and performance and compile time improvements.
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]70</p>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]71
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]72</div>
73
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]74<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]75<div class="doc_subsection">
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]76<a name="newfeatures">New Features in LLVM 1.8</a>
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]77</div>
Brian Gaeke6b31beb2004-01-16 21:55:04 +0000[diff] [blame]78
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]79<!--_________________________________________________________________________-->
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]80<div class="doc_subsubsection"><a name="dwarf">DWARF debugging
81support </a></div>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]82
83<div class="doc_text">
84
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]85<p>The llvm-gcc4 C front-end now generates debugging info for C and C++. This
86information is propagated through the compiler and the code generator can
87currently produce DWARF debugging information from it. DWARF is a standard
88debugging format used on many platforms, but currently LLVM only includes
89target support for Mac OS X targets for the 1.8 release.
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]90</p>
91
92</div>
93
94<!--_________________________________________________________________________-->
95<div class="doc_subsubsection"><a name="inlineasm">Inline Assembly
96Support</a></div>
97
98<div class="doc_text">
99
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]100<p>Inline assembly support is substantially improved in LLVM 1.8 over LLVM 1.7.
101Many unsupported features are now supported, and inline asm support in the X86
102backend is far better. llvm-gcc4 now supports global register variables as
103well.</p>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]104
105</div>
106
107<!--_________________________________________________________________________-->
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]108<div class="doc_subsubsection"><a name="loopopt">Loop Optimizer Improvements</a></div>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]109
110<div class="doc_text">
111
Chris Lattner49e693e2006-08-09 04:08:52 +0000[diff] [blame]112<p>The loop optimizer passes now uses "Loop-Closed SSA Form", which makes it
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]113easier to update SSA form as loop transformations change the code. An
114immediate benefit of this is that the loop unswitching pass can now unswitch
115loops in more cases.
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]116</p>
117
118</div>
119
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]120<!--_________________________________________________________________________-->
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]121<div class="doc_subsubsection"><a name="jumptab">Jump Table Support for Switches
122</a></div>
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]123
124<div class="doc_text">
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]125
126<p>The code generator now lowers switch statements to jump tables, providing
127significant performance boosts for applications (e.g. interpreters) whose
128performance is highly correlated to switch statement performance.</p>
129
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]130</div>
131
Chris Lattner1c1a85c2006-04-19 04:02:47 +0000[diff] [blame]132<!--_________________________________________________________________________-->
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]133<div class="doc_subsubsection"><a name="jitrelease">Deallocation of JIT'd
134Machine Code
135</a></div>
Chris Lattner1c1a85c2006-04-19 04:02:47 +0000[diff] [blame]136
137<div class="doc_text">
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]138
139<p>The LLVM JIT now allows clients to deallocate machine code JIT'd to its code
140buffer. This is important for long living applications that depend on the JIT.
141</p>
142
Chris Lattner1c1a85c2006-04-19 04:02:47 +0000[diff] [blame]143</div>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]144
145<!--_________________________________________________________________________-->
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]146<div class="doc_subsubsection"><a name="other">Other Improvements</a></div>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]147
Chris Lattner58504a62006-02-05 06:39:36 +0000[diff] [blame]148<div class="doc_text">
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]149
150<p>This release includes many other improvements, including improvements to
151 the optimizers and code generators (improving the generated code) changes to
152 speed up the compiler in many ways (improving algorithms and fine tuning
153 code), and changes to reduce the code size of the compiler itself.</p>
154
155<p>More specific changes include:</p>
156
Chris Lattner58504a62006-02-05 06:39:36 +0000[diff] [blame]157<ul>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]158<li>LLVM 1.8 includes an initial ARM backend. This backend is in early
159 development stages.</li>
160<li>LLVM 1.8 now includes significantly better support for mingw and
161 cygwin.</li>
162<li>The <a href="CommandGuide/html/llvm-config.html">llvm-config</a> tool is
163 now built by default and has several new features.</li>
164<li>The X86 and PPC backends now use the correct platform ABI for passing
165 vectors as arguments to functions.</li>
166<li>The X86 backend now includes support for the Microsoft ML assembler
167 ("MASM").</li>
168<li>The PowerPC backend now pattern matches the 'rlwimi' instruction more
169 aggressively.</li>
170<li>Most of LLVM is now built with "-pedantic", ensuring better portability
171 to more C++ Compilers.</li>
172<li>The PowerPC backend now includes initial 64-bit support. The JIT is not
173 complete, and the static compiler has a couple of known bugs, but support
174 is mostly in place. LLVM 1.9 will include completed PPC-64 support. </li>
Chris Lattner738bd302006-04-18 06:32:08 +0000[diff] [blame]175
Chris Lattner58504a62006-02-05 06:39:36 +0000[diff] [blame]176</ul>
177</div>
John Criswelle531ec52005-06-29 16:22:34 +0000[diff] [blame]178
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]179<!--=========================================================================-->
180<div class="doc_subsection">
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]181<a name="changes">Significant Changes in LLVM 1.8</a>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]182</div>
183
184<div class="doc_text">
185<ul>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]186<li>The LLVM "SparcV9" backend (deprecated in LLVM 1.7) has been removed in
187LLVM 1.8. The LLVM "Sparc" backend replaces it.</li>
188<li>The --version option now prints more useful information, including the
189 build configuration for the tool.</li>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]190</ul>
191</div>
192
193
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]194<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]195<div class="doc_section">
196 <a name="portability">Portability and Supported Platforms</a>
197</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]198<!-- *********************************************************************** -->
199
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]200<div class="doc_text">
201
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]202<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]203
204<ul>
Reid Spencer00812e22005-05-17 02:47:27 +0000[diff] [blame]205 <li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
206 (and probably other unix-like systems).</li>
Chris Lattner7ea41e32006-08-09 04:10:32 +0000[diff] [blame^]207<li>Intel and AMD machines running on Win32 using MinGW libraries (native)</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]208<li>Sun UltraSPARC workstations running Solaris 8.</li>
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]209<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
210 support is available for native builds with Visual C++).</li>
Chris Lattnerfeaf9602005-10-29 05:14:01 +0000[diff] [blame]211<li>PowerPC and X86-based Mac OS X systems, running 10.2 and above.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]212<li>Alpha-based machines running Debian GNU/Linux.</li>
213<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]214</ul>
215
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]216<p>The core LLVM infrastructure uses
217<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
218to the machine and operating system on which it is built. However, minor
219porting may be required to get LLVM to work on new platforms. We welcome your
220portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]221
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]222</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]223
224<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]225<div class="doc_section">
226 <a name="knownproblems">Known Problems</a>
227</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]228<!-- *********************************************************************** -->
229
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]230<div class="doc_text">
231
232<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]233component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]234sections. If you run into a problem, please check the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]235href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]236there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]237
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]238</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]239
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]240<!-- ======================================================================= -->
241<div class="doc_subsection">
242 <a name="experimental">Experimental features included with this release</a>
243</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]244
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]245<div class="doc_text">
246
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]247<p>The following components of this LLVM release are either untested, known to
248be broken or unreliable, or are in early development. These components should
249not be relied on, and bugs should not be filed against them, but they may be
250useful to some people. In particular, if you would like to work on one of these
Chris Lattner49e693e2006-08-09 04:08:52 +0000[diff] [blame]251components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]252
253<ul>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]254<li>The <tt>-cee</tt> pass is known to be buggy, and may be removed in in a
255 future release.</li>
Chris Lattner58504a62006-02-05 06:39:36 +0000[diff] [blame]256<li>The IA64 code generator is experimental.</li>
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]257<li>The Alpha JIT is experimental.</li>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]258<li>"<tt>-filetype=asm</tt>" (the default) is the only supported value for the
259 <tt>-filetype</tt> llc option.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]260</ul>
261
262</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]263
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]264<!-- ======================================================================= -->
265<div class="doc_subsection">
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]266 <a name="build">Known problems with the Build System</a>
267</div>
268
269<div class="doc_text">
270
271<ul>
Chris Lattner8bb0a6c2006-04-20 04:24:28 +0000[diff] [blame]272<li>none yet</li>
John Criswellc0c186d2005-11-08 21:11:33 +0000[diff] [blame]273</ul>
274</div>
275
276
277<!-- ======================================================================= -->
278<div class="doc_subsection">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]279 <a name="core">Known problems with the LLVM Core</a>
280</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]281
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]282<div class="doc_text">
283
284<ul>
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]285 <li>In the JIT, <tt>dlsym()</tt> on a symbol compiled by the JIT will not
286 work.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]287</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]288</div>
289
290<!-- ======================================================================= -->
291<div class="doc_subsection">
292 <a name="c-fe">Known problems with the C front-end</a>
293</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]294
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]295<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]296<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]297
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]298<div class="doc_text">
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]299
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]300<p>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]301llvm-gcc3 has many significant problems that are fixed by llvm-gcc4.
Chris Lattnercf797e92006-04-19 04:12:01 +0000[diff] [blame]302Two major ones include:</p>
Chris Lattnerc5d658a2006-03-03 00:34:26 +0000[diff] [blame]303
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]304<ul>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]305<li>With llvm-gcc3,
306 C99 variable sized arrays do not release stack memory when they go out of
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]307 scope. Thus, the following program may run out of stack space:
308<pre>
309 for (i = 0; i != 1000000; ++i) {
310 int X[n];
311 foo(X);
312 }
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]313</pre></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]314
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]315<li>With llvm-gcc3, Initialization of global union variables can only be done <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]316href="http://llvm.org/PR162">with the largest union member</a>.</li>
Chris Lattnerf580cdc2004-03-16 21:39:04 +0000[diff] [blame]317
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]318</ul>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]319
320<p>llvm-gcc4 is far more stable and produces better code than llvm-gcc3, but
321does not currently support Link-Time-Optimization or C++ Exception Handling,
322which llvm-gcc3 does.</p>
323
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]324</div>
325
326<!-- _______________________________________________________________________ -->
327<div class="doc_subsubsection">
328 Notes
329</div>
330
331<div class="doc_text">
332
333<ul>
334
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]335<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]336support for floating point data types of any size other than 32 and 64
337bits.</li>
338
339<li>The following Unix system functionality has not been tested and may not
340work:
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]341 <ol>
342 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
343 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
344 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
345 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
346 - These functions have not been tested.
347 </ol></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]348
349<li>Although many GCC extensions are supported, some are not. In particular,
350 the following extensions are known to <b>not be</b> supported:
351 <ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]352 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]353 <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>
354 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
355 <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 Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]356 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]357 <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>
358 <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 Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]359 <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>
360 <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>
Tanya Lattner014e5f52004-12-08 18:25:34 +0000[diff] [blame]361 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]362 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]363 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]364
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]365 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]366 attribute means that the LLVM compiler ignores the presence of the attribute,
367 but the code should still work. An unsupported attribute is one which is
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]368 ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]369 the program.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]370
371 <ol>
372 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
373 Arrays whose length is computed at run time.<br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]374 Supported, but allocated stack space is not freed until the function returns (noted above).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]375
376 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]377
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]378 Declaring that functions have no side effects or that they can never
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]379 return.<br>
380
381 <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]382 <tt>noreturn</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
Chris Lattneraef8c642005-12-05 05:23:06 +0000[diff] [blame]383 <tt>unused</tt>, <tt>used</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]384 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
385
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]386 <b>Ignored:</b> <tt>noinline</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]387 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
388 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
389
Chris Lattneraef8c642005-12-05 05:23:06 +0000[diff] [blame]390 <b>Unsupported:</b> <tt>section</tt>, <tt>alias</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]391 <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
392 <tt>fastcall</tt>, all other target specific attributes</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]393
394 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
395 Specifying attributes of variables.<br>
396 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
397 <tt>deprecated</tt>, <tt>transparent_union</tt>,
Chris Lattneraef8c642005-12-05 05:23:06 +0000[diff] [blame]398 <tt>unused</tt>, <tt>used</tt>, <tt>weak</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]399
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]400 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
401 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
402 <tt>vector_size</tt>, <tt>dllimport</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]403 <tt>dllexport</tt>, all target specific attributes.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]404
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]405 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.<br>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]406 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]407 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]408
409 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
410 all target specific attributes.</li>
411
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]412 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
413 Other built-in functions.<br>
414 We support all builtins which have a C language equivalent (e.g.,
415 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
416 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Chris Lattnerceebeb62004-06-18 06:26:29 +0000[diff] [blame]417 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
418 (currently ignored). We also support builtins for ISO C99 floating
Chris Lattner7939b782005-05-07 02:21:21 +0000[diff] [blame]419 point comparison macros (e.g., <tt>__builtin_islessequal</tt>),
420 <tt>__builtin_prefetch</tt>, <tt>__builtin_popcount[ll]</tt>,
421 <tt>__builtin_clz[ll]</tt>, and <tt>__builtin_ctz[ll]</tt>.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]422 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]423
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]424 <p>The following extensions <b>are</b> known to be supported:</p>
425
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]426 <ol>
Chris Lattner7fe97dd2004-03-16 08:54:07 +0000[diff] [blame]427 <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 Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]428 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
429 <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 Lattnerca26c3e2004-06-22 03:48:17 +0000[diff] [blame]430 <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 Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]431 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
432 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
433 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
434 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
435 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
436 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
437 <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>
438 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
439 <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 Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]440 <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 Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]441 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Initializers.html#Initializers">Initializers</a>: Non-constant initializers.</li>
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]442 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
443or arrays as values.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]444 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Designated-Inits.html#Designated%20Inits">Designated Inits</a>: Labeling elements of initializers.</li>
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]445 <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 Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]446 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
447 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
448 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
Tanya Lattner78537e42004-12-08 18:29:38 +0000[diff] [blame]449 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Comments.html#C_002b_002b-Comments">C++ Comments</a>: C++ comments are recognized.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]450 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
451 <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>
452 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
453 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
454 <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>
455 <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>
456 <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 Lattner25795bc2004-02-14 04:08:29 +0000[diff] [blame]457 <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 Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]458 <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>
459 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute%20Syntax">Attribute Syntax</a>: Formal syntax for attributes.</li>
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]460 </ol></li>
461
462</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]463
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]464<p>If you run into GCC extensions which have not been included in any of these
465lists, please let us know (also including whether or not they work).</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]466
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]467</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]468
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]469<!-- ======================================================================= -->
470<div class="doc_subsection">
471 <a name="c++-fe">Known problems with the C++ front-end</a>
472</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]473
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]474<div class="doc_text">
475
Reid Spencere09ca642004-12-07 08:39:08 +0000[diff] [blame]476<p>For this release, the C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]477tested and works for a number of non-trivial programs, including LLVM
478itself.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]479
480</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]481
482<!-- _______________________________________________________________________ -->
Chris Lattner3a51be12004-02-14 04:12:41 +0000[diff] [blame]483<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]484
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]485<div class="doc_text">
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]486
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]487<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]488<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]489 front-end</a>.</li>
Chris Lattner7962f712004-07-17 02:04:41 +0000[diff] [blame]490
Chris Lattnerd5713882004-08-02 20:28:44 +0000[diff] [blame]491</ul>
492
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]493</div>
494
495<!-- _______________________________________________________________________ -->
496<div class="doc_subsubsection">
497 Notes
498</div>
499
500<div class="doc_text">
501
502<ul>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]503
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]504<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]505 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]506 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]507 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]508 better than most compilers).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]509
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]510<li>The LLVM C++ front-end follows the <a
511 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
512 This document, which is not Itanium specific, specifies a standard for name
513 mangling, class layout, v-table layout, RTTI formats, and other C++
514 representation issues. Because we use this API, code generated by the LLVM
515 compilers should be binary compatible with machine code generated by other
516 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
517 <i>However</i>, the exception handling mechanism used by LLVM is very
518 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]519 interact correctly</b>. </li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]520
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]521</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]522
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]523</div>
524
525<!-- ======================================================================= -->
526<div class="doc_subsection">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]527 <a name="c-be">Known problems with the C back-end</a>
528</div>
529
530<div class="doc_text">
531
532<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]533
534<li>The C back-end produces code that violates the ANSI C Type-Based Alias
535Analysis rules. As such, special options may be necessary to compile the code
536(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]537problem probably cannot be fixed.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]538
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]539<li><a href="http://llvm.org/PR56">Zero arg vararg functions are not
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]540supported</a>. This should not affect LLVM produced by the C or C++
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]541frontends.</li>
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]542
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]543<li>The C backend does not correctly implement the <a
544href="LangRef.html#i_stacksave"><tt>llvm.stacksave</tt></a> or
545<a href="LangRef.html#i_stackrestore"><tt>llvm.stackrestore</tt></a>
546intrinsics. This means that some code compiled by it can run out of stack
547space if they depend on these (e.g. C99 varargs).</li>
548
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]549</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]550
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]551</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]552
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000[diff] [blame]553<!-- ======================================================================= -->
554<div class="doc_subsection">
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]555 <a name="x86-be">Known problems with the X86 back-end</a>
556</div>
557
558<div class="doc_text">
559
560<ul>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]561<li>none yet.</li>
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]562</ul>
563
564</div>
565
566<!-- ======================================================================= -->
567<div class="doc_subsection">
568 <a name="ppc-be">Known problems with the PowerPC back-end</a>
569</div>
570
571<div class="doc_text">
572
573<ul>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]574<li><a href="http://llvm.org/PR642">PowerPC backend does not correctly
575implement ordered FP comparisons</a>.</li>
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]576</ul>
577
578</div>
579
580<!-- ======================================================================= -->
581<div class="doc_subsection">
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000[diff] [blame]582 <a name="alpha-be">Known problems with the Alpha back-end</a>
583</div>
584
585<div class="doc_text">
586
587<ul>
588
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]589<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
590appropriate nops inserted to ensure restartability.</li>
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000[diff] [blame]591
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000[diff] [blame]592</ul>
593
594</div>
595
Duraid Madina2e36d6e2005-05-14 05:48:13 +0000[diff] [blame]596<!-- ======================================================================= -->
597<div class="doc_subsection">
598 <a name="ia64-be">Known problems with the IA64 back-end</a>
599</div>
600
601<div class="doc_text">
602
603<ul>
604
605<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
606made where the argument is not 16-byte aligned, as required on IA64. (Strictly
607speaking this is not a bug in the IA64 back-end; it will also be encountered
608when building C++ programs using the C back-end.)</li>
609
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]610<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]611ABI compliant layout of v-tables</a>. In particular, it just stores function
612pointers instead of function descriptors in the vtable. This bug prevents
613mixing C++ code compiled with LLVM with C++ objects compiled by other C++
614compilers.</li>
Duraid Madina2e36d6e2005-05-14 05:48:13 +0000[diff] [blame]615
Chris Lattnerf9b1f462005-05-16 17:06:29 +0000[diff] [blame]616<li>There are a few ABI violations which will lead to problems when mixing LLVM
617output with code built with other compilers, particularly for floating-point
618programs.</li>
619
620<li>Defining vararg functions is not supported (but calling them is ok).</li>
Duraid Madina2e36d6e2005-05-14 05:48:13 +0000[diff] [blame]621
622</ul>
623
624</div>
625
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]626<!-- ======================================================================= -->
627<div class="doc_subsection">
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]628 <a name="sparc-be">Known problems with the SPARC back-end</a>
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]629</div>
630
631<div class="doc_text">
632
633<ul>
Chris Lattnerc71173a2006-04-19 04:05:21 +0000[diff] [blame]634<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
635 support the 64-bit SPARC ABI (-m64).</li>
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]636</ul>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]637
638</div>
639
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]640<!-- ======================================================================= -->
641<div class="doc_subsection">
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]642 <a name="arm-be">Known problems with the ARM back-end</a>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]643</div>
644
645<div class="doc_text">
646
647<ul>
Chris Lattnerd9ea0172006-08-08 17:27:28 +0000[diff] [blame]648<li>The ARM backend is currently in early development stages, it is not
649ready for production use.</li>
Chris Lattner44c933e2006-04-18 06:18:36 +0000[diff] [blame]650</ul>
651
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame]652</div>
653
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]654<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]655<div class="doc_section">
656 <a name="additionalinfo">Additional Information</a>
657</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]658<!-- *********************************************************************** -->
659
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]660<div class="doc_text">
661
Chris Lattner416db102005-05-16 17:13:10 +0000[diff] [blame]662<p>A wide variety of additional information is available on the <a
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]663href="http://llvm.org">LLVM web page</a>, including <a
664href="http://llvm.org/docs/">documentation</a> and <a
665href="http://llvm.org/pubs/">publications describing algorithms and
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]666components implemented in LLVM</a>. The web page also contains versions of the
667API documentation which is up-to-date with the CVS version of the source code.
668You can access versions of these documents specific to this release by going
669into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]670
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]671<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]672us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]673lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]674
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]675</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]676
677<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]678
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]679<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]680<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]681 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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683 <a href="http://validator.w3.org/check/referer"><img
684 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
685
Chris Lattnerc463b272005-10-29 07:07:09 +0000[diff] [blame]686 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]687 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]688</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]689
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]690</body>
691</html>