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gerrit-public.fairphone.software / toolchain / llvm-project / 8e06116b8a9877c71a79ebc3a9aa496932147311 / . / llvm / docs / ReleaseNotes.html
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Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]7 <title>LLVM 2.1 Release Notes</title>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]8</head>
9<body>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]10
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]11<div class="doc_title">LLVM 2.1 Release Notes</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]12
13<ol>
Misha Brukman80731b92003-11-22 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 Lattner77a51732004-04-30 22:17:12 +0000[diff] [blame]16 <li><a href="GettingStarted.html">Installation Instructions</a></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]17 <li><a href="#portability">Portability and Supported Platforms</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]18 <li><a href="#knownproblems">Known Problems</a>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]19 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]20</ol>
21
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]22<div class="doc_author">
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]23 <p>Written by the <a href="http://llvm.org">LLVM Team</a><p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]24</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]25
26<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]27<div class="doc_section">
28 <a name="intro">Introduction</a>
29</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]30<!-- *********************************************************************** -->
31
Misha Brukman80731b92003-11-22 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 Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]35infrastructure, release 2.1. Here we describe the status of LLVM, including
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]36major improvements from the previous release and any known problems. All LLVM
Chris Lattner98a33492007-05-09 04:58:11 +0000[diff] [blame]37releases may be downloaded from the <a href="http://llvm.org/releases/">LLVM
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]38releases web site</a>.</p>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]39
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]40<p>For more information about LLVM, including information about the latest
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]41release, please check out the <a href="http://llvm.org/">main LLVM
Chris Lattnere7525b52003-10-07 21:38:31 +0000[diff] [blame]42web site</a>. If you have questions or comments, the <a
43href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]44list</a> is a good place to send them.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]45
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]46<p>Note that if you are reading this file from a Subversion checkout or the
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]47main LLVM web page, this document applies to the <i>next</i> release, not the
48current one. To see the release notes for a specific releases, please see the
49<a href="http://llvm.org/releases/">releases page</a>.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]50
51</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]52
53<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]54<div class="doc_section">
55 <a name="whatsnew">What's New?</a>
56</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]57<!-- *********************************************************************** -->
58
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]59<div class="doc_text">
60
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]61<p>This is the twelfth public release of the LLVM Compiler Infrastructure.
62It includes many features and refinements from LLVM 2.0.</p>
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]63
Chris Lattner21a90402004-05-24 04:50:25 +0000[diff] [blame]64</div>
65
Chris Lattnerba7bd472003-12-06 20:22:41 +0000[diff] [blame]66<!--=========================================================================-->
Chris Lattner406bddf2005-05-15 05:44:51 +0000[diff] [blame]67<div class="doc_subsection">
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]68<a name="frontends">New Frontends</a>
Chris Lattner9f871732006-04-18 06:18:36 +0000[diff] [blame]69</div>
70
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]71<div class="doc_text">
Chris Lattner727c3742007-05-18 06:33:02 +0000[diff] [blame]72
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]73<p>LLVM 2.1 brings two new beta C front-ends. First, Duncan, Anton and Devang
Devang Pateld331c852007-09-21 18:02:24 +0000[diff] [blame]74has started syncing up llvm-gcc with GCC 4.2, yielding "llvm-gcc 4.2" (creative,
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]75huh?). llvm-gcc 4.2 has the promise to bring much better FORTRAN and Ada
76support to LLVM as well as features like atomic builtins, OpenMP, and many other
77things. Check it out!</p>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]78
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]79<p>Second, LLVM now includes its own native C and Objective-C front-end (C++ is
80in progress, but is not very far along) code named "<a
81href="http://clang.llvm.org/">clang</a>". This front-end has a number of great
82features, primarily aimed at source-level analysis and speeding up compile-time.
83At this point though, the LLVM Code Generator component is still very early in
84development, so it's mostly useful for people looking to build source-level
85analysis tools or source-to-source translators.</p>
Chris Lattner727c3742007-05-18 06:33:02 +0000[diff] [blame]86
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]87</div>
88
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]89<!--=========================================================================-->
90<div class="doc_subsection">
91<a name="optimizer">Optimizer Improvements</a>
92</div>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]93
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]94<div class="doc_text">
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]95
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]96<p>Some of the most noticable feature improvements this release have been in the
97optimizer, speeding it up and making it more aggressive. For example:</p>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]98
99<ul>
Tanya Lattner6ee68ca2007-05-16 23:25:46 +0000[diff] [blame]100
Owen Anderson5d913aa2007-09-25 02:10:58 +0000[diff] [blame]101<li>Owen Anderson wrote the new MemoryDependenceAnalysis pass, which provides
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]102 a lazy, caching layer on top of <a href="AliasAnalysis.html">
103 AliasAnalysis</a>. He then used it to rewrite
Owen Anderson5d913aa2007-09-25 02:10:58 +0000[diff] [blame]104 DeadStoreElimination which resulted in significantly better compile time in
105 common cases, </li>
106<li>Owen implemented the new GVN pass, which is also based on
107 MemoryDependenceAnalysis. This pass replaces GCSE/LoadVN in the standard
108 set of passes, providing more aggressive optimization at a some-what
109 improved compile-time cost.</li>
110<li>Owen implemented GVN-PRE, a partial redundancy elimination algorithm that
111 shares some details with the new GVN pass. It is still in need of compile
112 time tuning, and is not turned on by default.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]113<li>Devang merged ETForest and DomTree into a single easier to use data
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]114 structure. This makes it more obvious which datastructure to choose
115 (because there is only one) and makes the compiler more memory and time
116 efficient (less stuff to keep up-to-date).</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]117<li>Nick Lewycky improved loop trip count analysis to handle many more common
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]118 cases.</li>
Tanya Lattner6ee68ca2007-05-16 23:25:46 +0000[diff] [blame]119
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]120</ul>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]121
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]122</div>
123
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]124<!--=========================================================================-->
125<div class="doc_subsection">
126<a name="codegen">Code Generator Improvements</a>
127</div>
128
129<div class="doc_text">
130
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]131<p>One of the main focuses of this release was performance tuning and bug
132 fixing. In addition to these, several new major changes occurred:</p>
133
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]134<ul>
135
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]136<li>Dale finished up the Tail Merging optimization in the code generator, and
137 enabled it by default. This produces smaller code that is also faster in
138 some cases.</li>
139
140<li>Christopher Lamb implemented support for virtual register sub-registers,
141 which can be used to better model many forms of subregisters. As an example
142 use, he modified the X86 backend to use this to model truncates and
143 extends more accurately (leading to better code).</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]144
145<li>Dan Gohman changed the way we represent vectors before legalization,
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]146 significantly simplifying the SelectionDAG representation for these and
147 making the code generator faster for vector code.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]148
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]149<li>Evan contributed a new target independent if-converter. While it is
150 target independent, at this point only the ARM backend uses it so far.</li>
151
152<li>Evan rewrite the way the register allocator handles rematerialization,
153 allowing it to be much more effective on two-address targets like X86,
154 and taught it to fold loads away when possible (also a big win on X86).</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]155
156<li>Dan Gohman contributed support for better alignment and volatility handling
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]157 in the code generator, and significantly enhanced alignment analysis for SSE
158 load/store instructions. With his changes, an insufficiently-aligned SSE
159 load instruction turns into <tt>movups</tt>, for example.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]160
161<li>Duraid Madina contributed a new "bigblock" register allocator, and Roman
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]162 Levenstein contributed several big improvements. BigBlock is optimized for
163 code that uses very large basic blocks. It is slightly slower than the
164 "local" allocator, but produces much better code.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]165
Chris Lattner1af762f2007-09-21 17:43:52 +0000[diff] [blame]166<li>David Greene refactored the register allocator to split coalescing out from
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]167 allocation, making coalescers pluggable.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]168
169</ul>
170
171</div>
172
173
174<!--=========================================================================-->
175<div class="doc_subsection">
176<a name="targetspecific">Target Specific Improvements</a>
177</div>
Chris Lattner727c3742007-05-18 06:33:02 +0000[diff] [blame]178
Chris Lattner89e761c2006-04-18 06:32:08 +0000[diff] [blame]179<div class="doc_text">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]180<p>New features include:
181</p>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]182
183<ul>
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]184<li>Bruno Cardoso Lopes contributed initial MIPS support. It is sufficient to
185 run many small programs, but is still incomplete and is not yet
186 fully performant.</li>
187
188<li>Bill Wendling added SSSE3 support to the X86 backend.</li>
189
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]190<li>Nicholas Geoffray contributed improved linux/ppc ABI and JIT support.</li>
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]191
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]192<li>Dale Johannesen rewrote handling of 32-bit float values in the X86 backend
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]193 when using the floating point stack, fixing several nasty bugs.</li>
194
195<li>Dan contributed rematerialization support for the X86 backend, in addition
196 to several X86-specific micro optimizations.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]197</ul>
198
199</div>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]200
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]201
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]202<!--=========================================================================-->
203<div class="doc_subsection">
204<a name="llvmgccimprovements">llvm-gcc Improvements</a>
205</div>
Tanya Lattner6ee68ca2007-05-16 23:25:46 +0000[diff] [blame]206
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]207<div class="doc_text">
208<p>New features include:
209</p>
Tanya Lattner6ee68ca2007-05-16 23:25:46 +0000[diff] [blame]210
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]211<ul>
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]212<li>Duncan and Anton made significant progress chasing down a number of problems
213 with C++ Zero-Cost exception handling in llvm-gcc 4.0 and 4.2. It is now at
214 the point where it "just works" on linux/x86-32 and has partial support on
215 other targets.</li>
Tanya Lattner6ee68ca2007-05-16 23:25:46 +0000[diff] [blame]216
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]217<li>Devang and Duncan fixed a huge number of bugs relating to bitfields, pragma
218 pack, and variable sized fields in structures.</li>
Chris Lattner727c3742007-05-18 06:33:02 +0000[diff] [blame]219
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]220<li>Tanya implemented support for <tt>__attribute__((noinline))</tt> in
221 llvm-gcc, and added support for generic variable annotations which are
222 propagated into the LLVM IR, e.g.
223 "<tt>int X __attribute__((annotate("myproperty")));</tt>".</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]224
225<li>Sheng Zhou and Christopher Lamb implemented alias analysis support for
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]226"restrict" pointer arguments to functions.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]227
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]228<li>Duncan contributed support for trampolines (taking the address of a nested
229 functions), currently this is only supported in the x86 target.</li>
Tanya Lattner6ee68ca2007-05-16 23:25:46 +0000[diff] [blame]230
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]231<li>Lauro Ramos Venancio contributed support to encode alignment info in
232 load and store instructions, the foundation for other alignment-related
233 work.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]234</ul>
235
Chris Lattner89e761c2006-04-18 06:32:08 +0000[diff] [blame]236</div>
237
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]238
239<!--=========================================================================-->
240<div class="doc_subsection">
241<a name="coreimprovements">LLVM Core Improvements</a>
242</div>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]243
Chris Lattner0b7fd712006-04-19 04:02:47 +0000[diff] [blame]244<div class="doc_text">
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]245<p>New features include:
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]246</p>
247
248<ul>
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]249<li>Neil Booth contributed a new "APFloat" class, which ensures that floating
250 point representation and constant folding is not dependent on the host
251 architecture that builds the application. This support is the foundation
252 for "long double" support that will be wrapped up in LLVM 2.2.</li>
253
254<li>Based on the APFloat class, Dale redesigned the internals of the ConstantFP
255 class and has been working on extending the core and optimizer components to
256 support various target-specific 'long double's. We expect this work to be
257 completed in LLVM 2.2.</li>
Tanya Lattner6ee68ca2007-05-16 23:25:46 +0000[diff] [blame]258
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]259<li>LLVM now provides an LLVMBuilder class, which makes it significantly easier
260 to create LLVM IR instructions.</li>
Tanya Lattner6ee68ca2007-05-16 23:25:46 +0000[diff] [blame]261
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]262<li>Reid contributed support for intrinsics that take arbitrary integer typed
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]263 arguments. Dan Gohman and Chandler extended it to support arbitrary
264 floating point arguments and vectors.</li>
Chris Lattner8ce1ba42007-05-17 21:41:31 +0000[diff] [blame]265</ul>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]266
Chris Lattner8ce1ba42007-05-17 21:41:31 +0000[diff] [blame]267</div>
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]268
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]269<!--=========================================================================-->
270<div class="doc_subsection">
271<a name="otherimprovements">Other Improvements</a>
272</div>
273
274<div class="doc_text">
275<p>New features include:
276</p>
277
278<ul>
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]279<li>Sterling Stein contributed a new BrainF frontend, located in llvm/examples.
280 This shows a some of the more modern APIs for building a front-end, and
281 demonstrates JIT compiler support.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]282
Chris Lattner4734a352007-09-26 05:44:21 +0000[diff] [blame]283<li>David Green contributed a new <tt>--enable-expensive-checks</tt> configure
284 option which enables STL checking, and fixed several bugs exposed by
285 it.</li>
Chris Lattner0a1fd102007-09-21 03:54:09 +0000[diff] [blame]286</ul>
287
288</div>
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]289
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]290<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]291<div class="doc_section">
292 <a name="portability">Portability and Supported Platforms</a>
293</div>
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]294<!-- *********************************************************************** -->
295
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]296<div class="doc_text">
297
John Criswell64307722004-12-08 20:35:47 +0000[diff] [blame]298<p>LLVM is known to work on the following platforms:</p>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]299
300<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]301<li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
Reid Spencer9803b402005-05-17 02:47:27 +0000[diff] [blame]302 (and probably other unix-like systems).</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]303<li>PowerPC and X86-based Mac OS X systems, running 10.2 and above in 32-bit and
304 64-bit modes.</li>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]305<li>Intel and AMD machines running on Win32 using MinGW libraries (native)</li>
306<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
307 support is available for native builds with Visual C++).</li>
308<li>Sun UltraSPARC workstations running Solaris 8.</li>
John Criswelld5234922005-05-13 20:28:15 +0000[diff] [blame]309<li>Alpha-based machines running Debian GNU/Linux.</li>
310<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner2c7b0872004-06-01 18:22:41 +0000[diff] [blame]311</ul>
312
Brian Gaekee3e557e2004-05-09 05:28:35 +0000[diff] [blame]313<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 +0000[diff] [blame]318
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]319</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]320
321<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]322<div class="doc_section">
323 <a name="knownproblems">Known Problems</a>
324</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]325<!-- *********************************************************************** -->
326
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]327<div class="doc_text">
328
329<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]330component. As new problems are discovered, they will be added to these
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]331sections. If you run into a problem, please check the <a
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]332href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]333there isn't already one.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]334
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]335</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]336
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]337<!-- ======================================================================= -->
338<div class="doc_subsection">
339 <a name="experimental">Experimental features included with this release</a>
340</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]341
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]342<div class="doc_text">
343
Misha Brukmanfa50a222004-05-12 21:46:05 +0000[diff] [blame]344<p>The following components of this LLVM release are either untested, known to
345be broken or unreliable, or are in early development. These components should
346not be relied on, and bugs should not be filed against them, but they may be
347useful to some people. In particular, if you would like to work on one of these
Chris Lattner05a225b2006-08-09 04:08:52 +0000[diff] [blame]348components, please contact us on the <a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVMdev list</a>.</p>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]349
350<ul>
Bill Wendling982d57d2007-09-25 20:45:10 +0000[diff] [blame]351<li>The <tt>-cee</tt> pass is known to be buggy, and may be removed in a
Chris Lattner9f871732006-04-18 06:18:36 +0000[diff] [blame]352 future release.</li>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]353<li>C++ EH support is disabled for this release.</li>
354<li>The MSIL backend is experimental.</li>
Chris Lattnera38fe5f2006-02-05 06:39:36 +0000[diff] [blame]355<li>The IA64 code generator is experimental.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000[diff] [blame^]356<li>The Alpha backend is experimental.</li>
Chris Lattner9f871732006-04-18 06:18:36 +0000[diff] [blame]357<li>"<tt>-filetype=asm</tt>" (the default) is the only supported value for the
358 <tt>-filetype</tt> llc option.</li>
Chris Lattnerb911de42004-03-14 02:03:02 +0000[diff] [blame]359</ul>
360
361</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]362
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]363<!-- ======================================================================= -->
364<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]365 <a name="x86-be">Known problems with the X86 back-end</a>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]366</div>
367
368<div class="doc_text">
369
370<ul>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]371<li>The X86 backend does not yet support <a href="http://llvm.org/PR879">inline
Chris Lattner98a33492007-05-09 04:58:11 +0000[diff] [blame]372 assembly that uses the X86 floating point stack</a>.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000[diff] [blame^]373<li>The X86 backend occasionally has <a href="http://llvm.org/PR1649">alignment
374 problems</a> on operating systems that don't require 16-byte stack alignment
375 (including most non-darwin OS's like linux).</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]376</ul>
377
378</div>
379
380<!-- ======================================================================= -->
381<div class="doc_subsection">
382 <a name="ppc-be">Known problems with the PowerPC back-end</a>
383</div>
384
385<div class="doc_text">
386
387<ul>
388<li><a href="http://llvm.org/PR642">PowerPC backend does not correctly
389implement ordered FP comparisons</a>.</li>
Nicolas Geoffray77d99502007-05-15 09:21:28 +0000[diff] [blame]390<li>The Linux PPC32/ABI support needs testing for the interpreter and static
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]391compilation, and lacks support for debug information.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]392</ul>
393
394</div>
395
396<!-- ======================================================================= -->
397<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]398 <a name="arm-be">Known problems with the ARM back-end</a>
399</div>
400
401<div class="doc_text">
402
403<ul>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]404<li>Thumb mode works only on ARMv6 or higher processors. On sub-ARMv6
405processors, thumb program can crash or produces wrong
406results (<a href="http://llvm.org/PR1388">PR1388</a>).</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]407<li>Compilation for ARM Linux OABI (old ABI) is supported, but not fully tested.
408</li>
Chris Lattnerbee7b322007-05-23 04:39:32 +0000[diff] [blame]409<li>There is a bug in QEMU-ARM (<= 0.9.0) which causes it to incorrectly execute
410programs compiled with LLVM. Please use more recent versions of QEMU.</li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]411</ul>
412
413</div>
414
415<!-- ======================================================================= -->
416<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]417 <a name="sparc-be">Known problems with the SPARC back-end</a>
418</div>
419
420<div class="doc_text">
421
422<ul>
423<li>The SPARC backend only supports the 32-bit SPARC ABI (-m32), it does not
424 support the 64-bit SPARC ABI (-m64).</li>
425</ul>
426
427</div>
428
429<!-- ======================================================================= -->
430<div class="doc_subsection">
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]431 <a name="alpha-be">Known problems with the Alpha back-end</a>
432</div>
433
434<div class="doc_text">
435
436<ul>
437
438<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
439appropriate nops inserted to ensure restartability.</li>
440
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]441</ul>
442</div>
443
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]444<!-- ======================================================================= -->
445<div class="doc_subsection">
446 <a name="ia64-be">Known problems with the IA64 back-end</a>
447</div>
448
449<div class="doc_text">
450
451<ul>
452
453<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
454made where the argument is not 16-byte aligned, as required on IA64. (Strictly
455speaking this is not a bug in the IA64 back-end; it will also be encountered
456when building C++ programs using the C back-end.)</li>
457
458<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
459ABI compliant layout of v-tables</a>. In particular, it just stores function
460pointers instead of function descriptors in the vtable. This bug prevents
461mixing C++ code compiled with LLVM with C++ objects compiled by other C++
462compilers.</li>
463
464<li>There are a few ABI violations which will lead to problems when mixing LLVM
465output with code built with other compilers, particularly for floating-point
466programs.</li>
467
468<li>Defining vararg functions is not supported (but calling them is ok).</li>
469
Chris Lattner98a33492007-05-09 04:58:11 +0000[diff] [blame]470<li>The Itanium backend has bitrotted somewhat.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]471</ul>
472
473</div>
474
475<!-- ======================================================================= -->
476<div class="doc_subsection">
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]477 <a name="c-be">Known problems with the C back-end</a>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]478</div>
479
480<div class="doc_text">
481
482<ul>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]483<li><a href="http://llvm.org/PR802">The C backend does not support inline
484 assembly code</a>.</li>
Chris Lattner8e061162007-09-26 06:01:35 +0000[diff] [blame^]485<li><a href="http://llvm.org/PR1126">The C backend does not support vectors
486 yet</a>.</li>
487<li><a href="http://llvm.org/PR1126">The C backend does not support vectors
488 yet</a>.</li>
489<li><a href="http://llvm.org/PR1658">The C backend violates the ABI of common
490 C++ programs</a>, preventing intermixing between C++ compiled by the CBE and
491 C++ code compiled with LLC or native compilers.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]492</ul>
493
494</div>
John Criswell3bdbd302005-11-08 21:11:33 +0000[diff] [blame]495
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]496
497<!-- ======================================================================= -->
498<div class="doc_subsection">
499 <a name="c-fe">Known problems with the C front-end</a>
500</div>
Chris Lattner178f3db2003-10-02 05:07:23 +0000[diff] [blame]501
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]502<!-- _______________________________________________________________________ -->
Chris Lattner5a8a7282003-12-14 05:03:43 +0000[diff] [blame]503<div class="doc_subsubsection">Bugs</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]504
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]505<div class="doc_text">
Chris Lattner72a269f2006-03-03 00:34:26 +0000[diff] [blame]506
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]507<p>llvm-gcc4 does not currently support <a href="http://llvm.org/PR869">Link-Time
508Optimization</a> on most platforms "out-of-the-box". Please inquire on the
509llvmdev mailing list if you are interested.</p>
Chris Lattner44124232006-08-08 17:27:28 +0000[diff] [blame]510
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]511</div>
512
513<!-- _______________________________________________________________________ -->
514<div class="doc_subsubsection">
515 Notes
516</div>
517
518<div class="doc_text">
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]519<ul>
520
Chris Lattner2f131fe2007-05-17 22:02:24 +0000[diff] [blame]521<li><p>"long double" is silently transformed by the front-end into "double". There
522is no support for floating point data types of any size other than 32 and 64
523bits.</p></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]524
Chris Lattner2f131fe2007-05-17 22:02:24 +0000[diff] [blame]525<li><p>llvm-gcc does <b>not</b> support <tt>__builtin_apply</tt> yet.
526 See <a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</p>
527</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]528
Duncan Sandsea7a3262007-05-18 09:04:20 +0000[diff] [blame]529<li><p>llvm-gcc <b>partially</b> supports these GCC extensions:</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]530 <ol>
Chris Lattner2f131fe2007-05-17 22:02:24 +0000[diff] [blame]531 <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.<br>
532 Nested functions are supported, but llvm-gcc does not support non-local
533 gotos or taking the address of a nested function.</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]534
535 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html#Function%20Attributes">Function Attributes</a>:
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]536
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]537 Declaring that functions have no side effects or that they can never
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]538 return.<br>
539
Chris Lattner2f131fe2007-05-17 22:02:24 +0000[diff] [blame]540 <b>Supported:</b> <tt>alias</tt>, <tt>always_inline</tt>, <tt>cdecl</tt>,
541 <tt>constructor</tt>, <tt>destructor</tt>,
Anton Korobeynikove7cbbfc2006-11-18 08:04:48 +0000[diff] [blame]542 <tt>deprecated</tt>, <tt>fastcall</tt>, <tt>format</tt>,
Anton Korobeynikovc52614b2007-05-10 08:26:24 +0000[diff] [blame]543 <tt>format_arg</tt>, <tt>non_null</tt>, <tt>noreturn</tt>, <tt>regparm</tt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]544 <tt>section</tt>, <tt>stdcall</tt>, <tt>unused</tt>, <tt>used</tt>,
545 <tt>visibility</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]546
Chris Lattner2f131fe2007-05-17 22:02:24 +0000[diff] [blame]547 <b>Ignored:</b> <tt>noinline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
548 <tt>malloc</tt>, <tt>no_instrument_function</tt></li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]549 </ol>
Chris Lattner2f131fe2007-05-17 22:02:24 +0000[diff] [blame]550</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]551
Chris Lattner2f131fe2007-05-17 22:02:24 +0000[diff] [blame]552<li><p>llvm-gcc supports the vast majority of GCC extensions, including:</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]553
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]554 <ol>
Chris Lattner2f131fe2007-05-17 22:02:24 +0000[diff] [blame]555 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
556 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
557 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
558 Other built-in functions.</li>
559 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
560 Specifying attributes of variables.</li>
561 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Type-Attributes.html#Type%20Attributes">Type Attributes</a>: Specifying attributes of types.</li>
562 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
563 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
564 Arrays whose length is computed at run time.</li>
Chris Lattnerd3dc8502004-03-16 08:54:07 +0000[diff] [blame]565 <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 +0000[diff] [blame]566 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
567 <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 +0000[diff] [blame]568 <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 +0000[diff] [blame]569 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
570 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
571 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
572 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
573 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
574 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
575 <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>
576 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]577 <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>
578 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constraints.html#Constraints">Constraints</a>: Constraints for asm operands.</li>
579 <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>
580 <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>
581 <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>
582 <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>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]583 <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 +0000[diff] [blame]584 <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 +0000[diff] [blame]585 <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 +0000[diff] [blame]586 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
587or arrays as values.</li>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]588 <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 +0000[diff] [blame]589 <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 +0000[diff] [blame]590 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
591 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
592 <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 Lattner7591b822004-12-08 18:29:38 +0000[diff] [blame]593 <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 Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]594 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
595 <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>
596 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
597 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
598 <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>
599 <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>
600 <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 +0000[diff] [blame]601 <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 +0000[diff] [blame]602 <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>
603 <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 +0000[diff] [blame]604 </ol></li>
605
606</ul>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]607
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]608<p>If you run into GCC extensions which have not been included in any of these
609lists, please let us know (also including whether or not they work).</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]610
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]611</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]612
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]613<!-- ======================================================================= -->
614<div class="doc_subsection">
615 <a name="c++-fe">Known problems with the C++ front-end</a>
616</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]617
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]618<div class="doc_text">
619
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]620<p>The C++ front-end is considered to be fully
Chris Lattnerb5bb5972004-12-07 08:04:13 +0000[diff] [blame]621tested and works for a number of non-trivial programs, including LLVM
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]622itself, Qt, Mozilla, etc.</p>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]623
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]624<ul>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]625<li>llvm-gcc4 only has partial support for <a href="http://llvm.org/PR870">C++
626Exception Handling</a>, and it is not enabled by default.</li>
627
628<!-- NO EH Support!
Chris Lattnerd2a74272003-10-27 18:30:37 +0000[diff] [blame]629
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]630<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]631 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]632 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswell86a3a482003-12-18 16:43:17 +0000[diff] [blame]633 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]634 better than most compilers).</li>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]635
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]636<li>The LLVM C++ front-end follows the <a
637 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
638 This document, which is not Itanium specific, specifies a standard for name
639 mangling, class layout, v-table layout, RTTI formats, and other C++
640 representation issues. Because we use this API, code generated by the LLVM
641 compilers should be binary compatible with machine code generated by other
642 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
Chris Lattnerb81f10e2006-11-18 07:51:14 +0000[diff] [blame]643 <i>However</i>, the exception handling mechanism used by llvm-gcc3 is very
Chris Lattner62495762003-10-02 16:38:05 +0000[diff] [blame]644 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]645 interact correctly</b>. </li>
Chris Lattner97beb512007-05-14 06:56:09 +0000[diff] [blame]646-->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]647</ul>
Chris Lattner46ecf612003-10-07 22:14:37 +0000[diff] [blame]648
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]649</div>
650
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]651
Chris Lattnerb62a5f02005-05-15 16:01:20 +0000[diff] [blame]652
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]653<!-- *********************************************************************** -->
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]654<div class="doc_section">
655 <a name="additionalinfo">Additional Information</a>
656</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]657<!-- *********************************************************************** -->
658
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]659<div class="doc_text">
660
Chris Lattnercb5596d2005-05-16 17:13:10 +0000[diff] [blame]661<p>A wide variety of additional information is available on the <a
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]662href="http://llvm.org">LLVM web page</a>, in particular in the <a
663href="http://llvm.org/docs/">documentation</a> section. The web page also
Reid Spencerc7f87f22007-07-09 08:04:31 +0000[diff] [blame]664contains versions of the API documentation which is up-to-date with the
665Subversion version of the source code.
Misha Brukman96158092005-03-30 19:14:24 +0000[diff] [blame]666You can access versions of these documents specific to this release by going
667into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]668
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]669<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattnera69595e2005-10-29 07:07:09 +0000[diff] [blame]670us via the <a href="http://llvm.org/docs/#maillist"> mailing
Chris Lattnerb84f3322003-12-12 21:22:16 +0000[diff] [blame]671lists</a>.</p>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]672
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]673</div>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]674
675<!-- *********************************************************************** -->
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]676
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]677<hr>
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]678<address>
Misha Brukman8834af92003-12-21 22:53:21 +0000[diff] [blame]679 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]680 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
681 <a href="http://validator.w3.org/check/referer"><img
682 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
683
Chris Lattnere0c1df42007-05-18 00:44:29 +0000[diff] [blame]684 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]685 Last modified: $Date$
Misha Brukman68aab3b2003-11-22 01:23:39 +0000[diff] [blame]686</address>
Chris Lattner3d482502003-10-02 04:57:28 +0000[diff] [blame]687
Misha Brukman80731b92003-11-22 00:38:41 +0000[diff] [blame]688</body>
689</html>