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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 98a493c7cef0b81d499eae82a1f9b748d5e59eeb / . / docs / ReleaseNotes.html
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Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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4<head>
Reid Spencer6454ed32004-11-18 18:38:58 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]6 <link rel="stylesheet" href="llvm.css" type="text/css">
Chris Lattner78bf32b2004-12-09 22:22:58 +0000[diff] [blame]7 <title>LLVM 1.5 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 Lattner78bf32b2004-12-09 22:22:58 +0000[diff] [blame]11<div class="doc_title">LLVM 1.5 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 Lattner78bf32b2004-12-09 22:22:58 +0000[diff] [blame]23 <p>Written by the <a href="http://llvm.cs.uiuc.edu">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 Lattner78bf32b2004-12-09 22:22:58 +0000[diff] [blame]35infrastructure, release 1.5. 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
37up-to-date version of this document can be found on the <a
Chris Lattner78bf32b2004-12-09 22:22:58 +0000[diff] [blame]38href="http://llvm.cs.uiuc.edu/releases/1.5/">LLVM 1.5 web site</a>. If you are
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]39not reading this on the LLVM web pages, you should probably go there because
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]40this document may be updated after the release.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]41
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]42<p>For more information about LLVM, including information about the latest
43release, please check out the <a href="http://llvm.cs.uiuc.edu">main LLVM
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]44web site</a>. If you have questions or comments, the <a
45href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]46list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]47
Chris Lattner78bf32b2004-12-09 22:22:58 +0000[diff] [blame]48<p>Note that if you are reading this file from CVS or the main LLVM web page,
49this document applies to the <i>next</i> release, not the current one. To see
50the release notes for the current or previous releases, see the <a
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]51href="http://llvm.cs.uiuc.edu/releases/">releases page</a>.</p>
52
53</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]54
55<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]56<div class="doc_section">
57 <a name="whatsnew">What's New?</a>
58</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]59<!-- *********************************************************************** -->
60
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]61<div class="doc_text">
62
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]63<p>This is the sixth public release of the LLVM Compiler Infrastructure.</p>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]64
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]65<p> At this time, LLVM is known to correctly compile a wide range of C and C++
66programs, including the SPEC CPU95 &amp; 2000 suite. It includes bug fixes for
67those problems found since the 1.4 release and a large number of new features
68and enhancements, described below.</p>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]69
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]70</div>
71
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]72<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]73<div class="doc_subsection">
74<a name="newfeatures">New Features in LLVM 1.5</a>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]75</div>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]76
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]77<!--_________________________________________________________________________-->
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame^]78<div class="doc_subsubsection"><a name="newcg">New Native Code
Chris Lattnerb38da0f2005-05-15 15:33:21 +0000[diff] [blame]79Generators</a></div>
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]80
81<div class="doc_text">
82<p>
83This release includes new native code generators for <a
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame^]84href="#alpha-be">Alpha</a>, <a href="#ia64-be">IA-64</a>, and <a
85href="#sparcv8">SPARC-V8</a> (32-bit SPARC). These code generators are still
86beta quality, but are progressing rapidly.
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]87</p>
88</div>
89
90<!--_________________________________________________________________________-->
Chris Lattnerb38da0f2005-05-15 15:33:21 +0000[diff] [blame]91<div class="doc_subsubsection"><a name="selectiondag">New Instruction
92Selector Framework</a></div>
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]93
94<div class="doc_text">
95<p>This release includes a <a href="CodeGenerator.html#instselect">new framework
96for building instruction selectors</a>, which has long been the hardest part of
97building a new LLVM target. This framework handles a lot of the mundane (but
98easy to get wrong) details of writing the instruction selector, such as
99generating efficient code for <a
100href="LangRef.html#i_getelementptr">getelementptr</a> instructions, promoting
101small integer types to larger types (e.g. for RISC targets with one size of
102integer registers), expanding 64-bit integer operations for 32-bit hosts, etc.
103Currently, the X86, PowerPC, Alpha, and IA-64 backends use this framework. The
104SPARC backends will be migrated when time permits.
105</p>
106</div>
107
108<!--_________________________________________________________________________-->
Chris Lattnerb38da0f2005-05-15 15:33:21 +0000[diff] [blame]109<div class="doc_subsubsection"><a name="customccs">New Support For Custom
110Calling Conventions</a></div>
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]111
112<div class="doc_text">
113<p>LLVM 1.5 adds supports for <a href="LangRef.html#callingconv">custom and
114target-specific calling conventions</a>. Traditionally, the LLVM code
115generators match the native C calling conventions for a target. This is
116important for compatibility, but is not very flexible. This release allows
117custom calling conventions to be established for functions, and defines three
118target-independent conventions (C call, fast call, and cold call) which may be
119supported by code generators. When possible, the LLVM optimizer promotes C
120functions to use the "fastcc" convention, allowing the use of more efficient
121calling sequences (e.g., parameters are passed in registers in the X86 target).
122</p>
123
124<p>Targets may now also define target-specific calling conventions, allowing
125LLVM to fully support calling convention altering options (e.g. GCC's
126<tt>-mregparm</tt> flag) and well-defined target conventions (e.g. stdcall and
127fastcall on X86).</p>
128</div>
129
130<!--_________________________________________________________________________-->
Chris Lattnerb38da0f2005-05-15 15:33:21 +0000[diff] [blame]131<div class="doc_subsubsection"><a name="tailcalls">New Support for
132"Proper Tail Calls"</a></div>
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]133
134<div class="doc_text">
135<p>The release now includes support for <a
136href="http://doi.acm.org/10.1145/277650.277719">proper tail calls</a>, as
137required to implement languages like Scheme. Tail calls make use of two
138features: custom calling conventions (described above), which allow the code
139generator to emit code for the caller to deallocate its own stack when it
140returns. The second feature is a flag on the <a href="LangRef.html#i_call">call
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame^]141instruction</a>, which indicates that the callee does not access the caller's
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]142stack frame (indicating that it is acceptable to deallocate the caller stack
143before invoking the callee). LLVM proper tail calls run on the system stack (as
144do normal calls), supports indirect tail calls, tail calls with arbitrary
145numbers of arguments, tail calls where the callee requires more argument space
146than the caller, etc. The only case not supported are varargs calls, but that
147could be added if desired.
148</p>
149
150<p>In order for a front-end to get guaranteed tail call, it must mark functions
151as "fastcc", mark calls with the 'tail' marker, and follow the call with a
152return of the called value (or void). The optimizer and code generator attempt
153to handle more general cases, but the simple case will always work if the code
154generator supports tail calls. Here is a simple example:</p>
155
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame^]156<pre>
Chris Lattnera4faa4a2005-05-15 06:07:40 +0000[diff] [blame]157 fastcc int %bar(int %X, int(double, int)* %FP) { ;<i> fastcc</i>
158 %Y = tail call fastcc int %FP(double 0.0, int %X) ;<i> tail, fastcc</i>
159 ret int %Y
160 }
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame^]161</pre>
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]162
163<p>In LLVM 1.5, the X86 code generator is the only target that has been enhanced
164to support proper tail calls (other targets will be enhanced in future).
165Further, because this support was added very close to the release, it is
Chris Lattnera4faa4a2005-05-15 06:07:40 +0000[diff] [blame]166disabled by default. Pass <tt>-enable-x86-fastcc</tt> to llc to enable it (this
167will be enabled by default in the next release). The example above compiles to:
168</p>
169
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame^]170<pre>
Chris Lattnera4faa4a2005-05-15 06:07:40 +0000[diff] [blame]171 bar:
172 sub ESP, 8 # Callee uses more space than the caller
173 mov ECX, DWORD PTR [ESP + 8] # Get the old return address
174 mov DWORD PTR [ESP + 4], 0 # First half of 0.0
175 mov DWORD PTR [ESP + 8], 0 # Second half of 0.0
176 mov DWORD PTR [ESP], ECX # Put the return address where it belongs
177 jmp EDX # Tail call "FP"
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame^]178</pre>
Chris Lattnera4faa4a2005-05-15 06:07:40 +0000[diff] [blame]179
180<p>
181With fastcc on X86, the first two integer arguments are passed in EAX/EDX, the
182callee pops its arguments off the stack, and the argument area is always a
183multiple of 8 bytes in size.
184</p>
185
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]186</div>
187
188<!--_________________________________________________________________________-->
189<div class="doc_subsubsection">Other New Features</div>
190
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]191<div class="doc_text">
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]192<ol>
Chris Lattner74d74cd2004-12-11 06:10:52 +0000[diff] [blame]193 <li>LLVM now includes an <a href="http://llvm.cs.uiuc.edu/PR415">
Chris Lattnerda1f03c2005-01-22 18:45:35 +0000[diff] [blame]194 Interprocedural Sparse Conditional Constant Propagation</a> pass, named
Chris Lattner74d74cd2004-12-11 06:10:52 +0000[diff] [blame]195 -ipsccp, which is run by default at link-time.</li>
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]196 <li>LLVM 1.5 is now about 15% faster than LLVM 1.4 and its core data
197 structures use about 30% less memory.</li>
Chris Lattner2e12c742005-02-13 22:27:24 +0000[diff] [blame]198 <li>Support for Microsoft Visual Studio is improved, and <a
Chris Lattnera5d803e2005-02-14 22:58:38 +0000[diff] [blame]199 href="GettingStartedVS.html">now documented</a>.</li>
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]200 <li><a href="GettingStarted.html#config">Configuring LLVM to build a subset
201 of the available targets</a> is now implemented, via the
202 <tt>--enable-targets=</tt> option.</li>
Chris Lattnerd7934542005-02-28 16:52:28 +0000[diff] [blame]203 <li>LLVM can now create native shared libraries with '<tt>llvm-gcc ...
204 -shared -Wl,-native</tt>' (or with <tt>-Wl,-native-cbe</tt>).</li>
Chris Lattnerd03b3bc2005-03-11 06:16:26 +0000[diff] [blame]205 <li>LLVM now supports a new "<a href="LangRef.html#i_prefetch">llvm.prefetch
206 </a>" intrinsic, and llvm-gcc now supports __builtin_prefetch.
Chris Lattner7939b782005-05-07 02:21:21 +0000[diff] [blame]207 <li>LLVM now supports intrinsics for <a href="LangRef.html#int_count">bit
208 counting</a> and llvm-gcc now implements the GCC
209 <tt>__builtin_popcount</tt>, <tt>__builtin_ctz</tt>, and
210 <tt>__builtin_clz</tt> builtins.</li>
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]211 <li>LLVM now builds on HP-UX with the HP aCC Compiler.</li>
212 <li>The LLVM X86 backend can now emit Cygwin-compatible .s files.</li>
213 <li>LLVM now includes workarounds in the code generator generator which
214 reduces the likelyhood of <a href="http://llvm.cs.uiuc.edu/PR448">GCC
215 hitting swap during optimized builds</a>.</li>
Chris Lattnerb38da0f2005-05-15 15:33:21 +0000[diff] [blame]216 <li>The PowerPC backend generates far better code than in LLVM 1.4.</li>
Brian Gaeke6b31beb2004-01-16 21:55:04 +0000[diff] [blame]217</ol>
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]218</div>
Brian Gaeke6b31beb2004-01-16 21:55:04 +0000[diff] [blame]219
220<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]221<div class="doc_subsection">
222<a name="codequality">Code Quality Improvements in LLVM 1.5</a>
Chris Lattneraab56d42004-05-23 20:42:08 +0000[diff] [blame]223</div>
Chris Lattner89ca2b82003-10-27 17:06:39 +0000[diff] [blame]224
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]225<div class="doc_text">
Chris Lattner89ca2b82003-10-27 17:06:39 +0000[diff] [blame]226<ol>
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]227<li>The -globalopt pass now promotes non-address-taken static globals that are
228only accessed in main to SSA registers.</li>
229
Chris Lattner1b592f02005-05-15 06:09:55 +0000[diff] [blame]230<li>The new -simplify-libcalls pass improves code generated for well-known
231library calls. The pass optimizes calls to many of the string, memory, and
232standard I/O functions (e.g. replace the calls with simpler/faster calls) when
233possible, given information known statically about the arguments to the call.
234</li>
235
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]236<li>Loops with trip counts based on array pointer comparisons (e.g. "<tt>for (i
237= 0; &amp;A[i] != &amp;A[100]; ++i) ...</tt>") are optimized better than before,
238which primarily helps iterator-intensive C++ codes.</li>
239
240<li>The code generator now uses information about takes advantage of commutative
241two-address instructions when performing register allocation.</li>
242
243
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]244</ol>
Reid Spencer8e0262f2004-05-23 17:23:13 +0000[diff] [blame]245</div>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]246
247<!--=========================================================================-->
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]248<div class="doc_subsection">
249<a name="bugfix">Significant Bugs Fixed in LLVM 1.5</a>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]250</div>
251
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]252<div class="doc_text">
253
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]254
Chris Lattnerf54e9cb2005-02-14 16:57:55 +0000[diff] [blame]255<p>Bugs fixed in the LLVM Core:</p>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]256<ol>
Chris Lattnerbfd24682004-12-29 04:39:50 +0000[diff] [blame]257 <li><a href="http://llvm.cs.uiuc.edu/PR491">[dse] DSE deletes stores that
258 are partially overwritten by smaller stores</a></li>
Chris Lattnerf79e57e2005-04-19 06:08:04 +0000[diff] [blame]259 <li><a href="http://llvm.cs.uiuc.edu/PR548">[instcombine] miscompilation of
260 setcc or setcc in one case</a></li>
Chris Lattner8a458762005-05-15 05:44:51 +0000[diff] [blame]261 <li>Transition code for LLVM 1.0 style varargs was removed from the .ll file
262 parser. LLVM 1.0 bytecode files are still supported. </li>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]263</ol>
264
Chris Lattnerf54e9cb2005-02-14 16:57:55 +0000[diff] [blame]265<p>Code Generator Bugs:</p>
266<ol>
267 <li><a href="http://llvm.cs.uiuc.edu/PR490">[cbackend] Logical constant
268 expressions (and/or/xor) not implemented</a></li>
269 <li><a href="http://llvm.cs.uiuc.edu/PR511">[cbackend] C backend does not
270 respect 'volatile'</a></li>
271</ol>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]272
Chris Lattnerf54e9cb2005-02-14 16:57:55 +0000[diff] [blame]273<p>Bugs in the C/C++ front-end:</p>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]274<ol>
Chris Lattner8de9f232005-01-03 04:20:21 +0000[diff] [blame]275 <li><a href="http://llvm.cs.uiuc.edu/PR487">[llvmgcc] llvm-gcc incorrectly
276 rejects some constant initializers involving the addresses of array
277 elements</a></li>
Chris Lattnerf832f6a2005-02-11 19:29:52 +0000[diff] [blame]278 <li><a href="http://llvm.cs.uiuc.edu/PR501">[llvm-g++] Crash compiling
279 anonymous union</a></li>
Chris Lattnerf54e9cb2005-02-14 16:57:55 +0000[diff] [blame]280 <li><a href="http://llvm.cs.uiuc.edu/PR509">[llvm-g++] Do not use dynamic
281 initialization where static init will do</a></li>
Chris Lattner4a9dc292005-02-15 05:28:06 +0000[diff] [blame]282 <li><a href="http://llvm.cs.uiuc.edu/PR510">[llvmgcc] Field offset
283 miscalculated for some structure fields following bit fields</a></li>
Chris Lattner5ad907a2005-02-15 07:02:12 +0000[diff] [blame]284 <li><a href="http://llvm.cs.uiuc.edu/PR513">[llvm-g++] Temporary lifetimes
285 incorrect for short circuit logical operations</a></li>
Chris Lattnerc1f90a92005-02-19 07:29:25 +0000[diff] [blame]286 <li><a href="http://llvm.cs.uiuc.edu/PR517">[llvm-gcc] Crash compiling
287 bitfield &lt;-&gt; aggregate assignment</a></li>
Chris Lattner94f6ac72005-02-19 17:13:20 +0000[diff] [blame]288 <li><a href="http://llvm.cs.uiuc.edu/PR520">[llvm-g++] Error compiling
Chris Lattnerd12b9b22005-02-19 17:17:32 +0000[diff] [blame]289 virtual function thunk with an unnamed argument</a></li>
Chris Lattner290d2292005-02-20 23:31:49 +0000[diff] [blame]290 <li><a href="http://llvm.cs.uiuc.edu/PR522">[llvm-gcc] Crash on certain
291 C99 complex number routines</a></li>
Chris Lattner2a3cdf72005-02-27 19:31:02 +0000[diff] [blame]292 <li><a href="http://llvm.cs.uiuc.edu/PR529">[llvm-g++] Crash using placement
293 new on an array type</a></li>
Brian Gaekee77c8e72004-08-24 07:43:48 +0000[diff] [blame]294</ol>
295
Chris Lattner80453c92004-05-24 04:50:25 +0000[diff] [blame]296</div>
Reid Spencer8e0262f2004-05-23 17:23:13 +0000[diff] [blame]297
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]298<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]299<div class="doc_section">
300 <a name="portability">Portability and Supported Platforms</a>
301</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]302<!-- *********************************************************************** -->
303
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]304<div class="doc_text">
305
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]306<p>LLVM is known to work on the following platforms:</p>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]307
308<ul>
309<li>Intel and AMD machines running Red Hat Linux and FreeBSD (and probably
310 other unix-like systems).</li>
311<li>Sun UltraSPARC workstations running Solaris 8.</li>
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]312<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
313 support is available for native builds with Visual C++).</li>
314<li>PowerPC-based Mac OS X systems, running 10.2 and above.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]315<li>Alpha-based machines running Debian GNU/Linux.</li>
316<li>Itanium-based machines running Linux and HP-UX.</li>
Chris Lattner4654bdb2004-06-01 18:22:41 +0000[diff] [blame]317</ul>
318
Brian Gaekeb0fd7612004-05-09 05:28:35 +0000[diff] [blame]319<p>The core LLVM infrastructure uses
320<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
321to the machine and operating system on which it is built. However, minor
322porting may be required to get LLVM to work on new platforms. We welcome your
323portability patches and reports of successful builds or error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]324
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]325</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]326
327<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]328<div class="doc_section">
329 <a name="knownproblems">Known Problems</a>
330</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]331<!-- *********************************************************************** -->
332
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]333<div class="doc_text">
334
335<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]336component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]337sections. If you run into a problem, please check the <a
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]338href="http://llvm.cs.uiuc.edu/bugs/">LLVM bug database</a> and submit a bug if
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]339there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]340
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]341</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]342
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]343<!-- ======================================================================= -->
344<div class="doc_subsection">
345 <a name="experimental">Experimental features included with this release</a>
346</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]347
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]348<div class="doc_text">
349
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]350<p>The following components of this LLVM release are either untested, known to
351be broken or unreliable, or are in early development. These components should
352not be relied on, and bugs should not be filed against them, but they may be
353useful to some people. In particular, if you would like to work on one of these
354components, please contact us on the llvmdev list.</p>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]355
356<ul>
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]357<li>The following passes are incomplete or buggy, and may be removed in future
Chris Lattner1fe848e2005-01-28 06:13:52 +0000[diff] [blame]358 releases: <tt>-cee, -branch-combine, -instloops, -paths, -pre</tt></li>
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]359<li>The <tt>llvm-db</tt> tool is in a very early stage of development, but can
360 be used to step through programs and inspect the stack.</li>
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]361<li>The "iterative scan" register allocator (enabled with
362 <tt>-regalloc=iterativescan</tt>) is not stable.</li>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]363<li>The SparcV8, Alpha, and IA64 code generators are experimental.</li>
Chris Lattnerf5ee1702004-03-14 02:03:02 +0000[diff] [blame]364</ul>
365
366</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]367
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]368<!-- ======================================================================= -->
369<div class="doc_subsection">
370 <a name="core">Known problems with the LLVM Core</a>
371</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]372
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]373<div class="doc_text">
374
375<ul>
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]376 <li>In the JIT, <tt>dlsym()</tt> on a symbol compiled by the JIT will not
377 work.</li>
Reid Spencer4f86f9c2004-11-25 22:38:30 +0000[diff] [blame]378 <li>The JIT does not use mutexes to protect its internal data structures. As
379 such, execution of a threaded program could cause these data structures to be
380 corrupted.
381 </li>
Reid Spencer4f86f9c2004-11-25 22:38:30 +0000[diff] [blame]382 <li><a href="http://llvm.cs.uiuc.edu/PR240">The lower-invoke pass does not
383 mark values live across a setjmp as volatile</a>. This missing feature
384 only affects targets whose setjmp/longjmp libraries do not save and restore
385 the entire register file.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]386</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]387</div>
388
389<!-- ======================================================================= -->
390<div class="doc_subsection">
391 <a name="c-fe">Known problems with the C front-end</a>
392</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]393
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]394<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]395<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]396
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]397<div class="doc_text">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]398<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]399<li>C99 Variable sized arrays do not release stack memory when they go out of
400 scope. Thus, the following program may run out of stack space:
401<pre>
402 for (i = 0; i != 1000000; ++i) {
403 int X[n];
404 foo(X);
405 }
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]406</pre></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]407
Misha Brukman6df9e2c2004-05-12 21:46:05 +0000[diff] [blame]408<li>Initialization of global union variables can only be done <a
Misha Brukman43ee2932004-12-04 00:45:09 +0000[diff] [blame]409href="http://llvm.cs.uiuc.edu/PR162">with the largest union member</a>.</li>
Chris Lattnerf580cdc2004-03-16 21:39:04 +0000[diff] [blame]410
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]411</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]412</div>
413
414<!-- _______________________________________________________________________ -->
415<div class="doc_subsubsection">
416 Notes
417</div>
418
419<div class="doc_text">
420
421<ul>
422
423<li>Inline assembly is not yet supported.</li>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]424
425<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]426support for floating point data types of any size other than 32 and 64
427bits.</li>
428
429<li>The following Unix system functionality has not been tested and may not
430work:
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]431 <ol>
432 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
433 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
434 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
435 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
436 - These functions have not been tested.
437 </ol></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]438
439<li>Although many GCC extensions are supported, some are not. In particular,
440 the following extensions are known to <b>not be</b> supported:
441 <ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]442 <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]443 <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>
444 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
445 <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]446 <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]447 <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>
448 <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]449 <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>
450 <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]451 <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]452 <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]453 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]454
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]455 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]456 attribute means that the LLVM compiler ignores the presence of the attribute,
457 but the code should still work. An unsupported attribute is one which is
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]458 ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]459 the program.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]460
461 <ol>
462 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
463 Arrays whose length is computed at run time.<br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]464 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]465
466 <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]467
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]468 Declaring that functions have no side effects or that they can never
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]469 return.<br>
470
471 <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]472 <tt>noreturn</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
473 <tt>unused</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]474 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
475
John Criswell0b5b5e92004-12-08 20:35:47 +0000[diff] [blame]476 <b>Ignored:</b> <tt>noinline</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]477 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
478 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
479
480 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>,
481 <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
482 <tt>fastcall</tt>, all other target specific attributes</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]483
484 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
485 Specifying attributes of variables.<br>
486 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
487 <tt>deprecated</tt>, <tt>transparent_union</tt>,
488 <tt>unused</tt>, <tt>weak</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]489
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]490 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
491 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
492 <tt>vector_size</tt>, <tt>dllimport</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]493 <tt>dllexport</tt>, all target specific attributes.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]494
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]495 <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]496 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]497 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]498
499 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
500 all target specific attributes.</li>
501
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]502 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
503 Other built-in functions.<br>
504 We support all builtins which have a C language equivalent (e.g.,
505 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
506 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Chris Lattnerceebeb62004-06-18 06:26:29 +0000[diff] [blame]507 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
508 (currently ignored). We also support builtins for ISO C99 floating
Chris Lattner7939b782005-05-07 02:21:21 +0000[diff] [blame]509 point comparison macros (e.g., <tt>__builtin_islessequal</tt>),
510 <tt>__builtin_prefetch</tt>, <tt>__builtin_popcount[ll]</tt>,
511 <tt>__builtin_clz[ll]</tt>, and <tt>__builtin_ctz[ll]</tt>.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]512 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]513
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]514 <p>The following extensions <b>are</b> known to be supported:</p>
515
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]516 <ol>
Chris Lattner7fe97dd2004-03-16 08:54:07 +0000[diff] [blame]517 <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]518 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
519 <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]520 <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]521 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
522 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
523 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
524 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
525 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
526 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
527 <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>
528 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
529 <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]530 <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]531 <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]532 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
533or arrays as values.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]534 <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]535 <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]536 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
537 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
538 <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]539 <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]540 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
541 <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>
542 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
543 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
544 <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>
545 <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>
546 <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]547 <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]548 <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>
549 <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]550 </ol></li>
551
552</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]553
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]554<p>If you run into GCC extensions which have not been included in any of these
555lists, please let us know (also including whether or not they work).</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]556
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]557</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]558
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]559<!-- ======================================================================= -->
560<div class="doc_subsection">
561 <a name="c++-fe">Known problems with the C++ front-end</a>
562</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]563
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]564<div class="doc_text">
565
Reid Spencere09ca642004-12-07 08:39:08 +0000[diff] [blame]566<p>For this release, the C++ front-end is considered to be fully
Chris Lattner7506b1d2004-12-07 08:04:13 +0000[diff] [blame]567tested and works for a number of non-trivial programs, including LLVM
568itself.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]569
570</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]571
572<!-- _______________________________________________________________________ -->
Chris Lattner3a51be12004-02-14 04:12:41 +0000[diff] [blame]573<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]574
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]575<div class="doc_text">
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]576
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]577<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]578<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]579 front-end</a>.</li>
Chris Lattner7962f712004-07-17 02:04:41 +0000[diff] [blame]580
Chris Lattnerd5713882004-08-02 20:28:44 +0000[diff] [blame]581<li><b>IA-64 specific</b>: The C++ front-end does not use <a
582href="http://llvm.cs.uiuc.edu/PR406">IA64 ABI compliant layout of v-tables</a>.
Chris Lattner7962f712004-07-17 02:04:41 +0000[diff] [blame]583In particular, it just stores function pointers instead of function
584descriptors in the vtable. This bug prevents mixing C++ code compiled with
Chris Lattner04db8082004-08-02 20:29:51 +0000[diff] [blame]585LLVM with C++ objects compiled by other C++ compilers.</li>
Chris Lattner7962f712004-07-17 02:04:41 +0000[diff] [blame]586
Chris Lattnerd5713882004-08-02 20:28:44 +0000[diff] [blame]587</ul>
588
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]589</div>
590
591<!-- _______________________________________________________________________ -->
592<div class="doc_subsubsection">
593 Notes
594</div>
595
596<div class="doc_text">
597
598<ul>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]599
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]600<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
601parser is significantly more standards compliant (and picky) than prior GCC
602versions. For more information, see the C++ section of the <a
Chris Lattner9e848092003-12-12 04:25:33 +0000[diff] [blame]603href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]604
605<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]606 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]607 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]608 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]609 better than most compilers).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]610
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]611<li>The LLVM C++ front-end follows the <a
612 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
613 This document, which is not Itanium specific, specifies a standard for name
614 mangling, class layout, v-table layout, RTTI formats, and other C++
615 representation issues. Because we use this API, code generated by the LLVM
616 compilers should be binary compatible with machine code generated by other
617 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
618 <i>However</i>, the exception handling mechanism used by LLVM is very
619 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]620 interact correctly</b>. </li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]621
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]622</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]623
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]624</div>
625
626<!-- ======================================================================= -->
627<div class="doc_subsection">
628 <a name="x86-be">Known problems with the X86 back-end</a>
629</div>
630
631<div class="doc_text">
632
633<ul>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]634 <li>None yet</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]635</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]636
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]637</div>
638
639<!-- ======================================================================= -->
640<div class="doc_subsection">
Misha Brukmanadb1c392004-07-12 16:55:41 +0000[diff] [blame]641 <a name="sparcv9-be">Known problems with the SparcV9 back-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]642</div>
643
644<div class="doc_text">
645
646<ul>
Misha Brukmanadb1c392004-07-12 16:55:41 +0000[diff] [blame]647<li><a href="http://llvm.cs.uiuc.edu/PR60">[sparcv9] SparcV9 backend miscompiles
648several programs in the LLVM test suite</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]649</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]650
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]651</div>
652
653<!-- ======================================================================= -->
654<div class="doc_subsection">
Chris Lattnerf32a5f52004-11-07 01:55:32 +0000[diff] [blame]655 <a name="ppc-be">Known problems with the PowerPC back-end</a>
656</div>
657
658<div class="doc_text">
659
660<ul>
John Criswell9321fa82005-05-13 20:28:15 +0000[diff] [blame]661<li>None yet</li>
Chris Lattnerf32a5f52004-11-07 01:55:32 +0000[diff] [blame]662</ul>
663
664</div>
665
666<!-- ======================================================================= -->
667<div class="doc_subsection">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]668 <a name="c-be">Known problems with the C back-end</a>
669</div>
670
671<div class="doc_text">
672
673<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]674
675<li>The C back-end produces code that violates the ANSI C Type-Based Alias
676Analysis rules. As such, special options may be necessary to compile the code
677(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]678problem probably cannot be fixed.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]679
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]680<li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]681supported</a>. This should not affect LLVM produced by the C or C++
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]682frontends.</li>
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]683
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]684</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]685
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]686</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]687
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000[diff] [blame]688<!-- ======================================================================= -->
689<div class="doc_subsection">
690 <a name="alpha-be">Known problems with the Alpha back-end</a>
691</div>
692
693<div class="doc_text">
694
695<ul>
696
697<li>On 21164s, some rare FP arithmatic sequences which may trap do not have the appropriate nops inserted to ensure restartability.</li>
698
699<li>Vararg functions are not supported.</li>
700
Andrew Lenharth01f40b32005-05-14 17:43:00 +0000[diff] [blame]701<li>Due to the vararg problems, C++ exceptions do not work. Small changes are required to the CFE (which break correctness in the exception handler) to compile the exception handling library (and thus the C++ standard library).</li>
702
Andrew Lenharth30a1f8f2005-05-03 16:59:09 +0000[diff] [blame]703</ul>
704
705</div>
706
Duraid Madina2e36d6e2005-05-14 05:48:13 +0000[diff] [blame]707<!-- ======================================================================= -->
708<div class="doc_subsection">
709 <a name="ia64-be">Known problems with the IA64 back-end</a>
710</div>
711
712<div class="doc_text">
713
714<ul>
715
716<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
717made where the argument is not 16-byte aligned, as required on IA64. (Strictly
718speaking this is not a bug in the IA64 back-end; it will also be encountered
719when building C++ programs using the C back-end.)</li>
720
721<li>There are a few ABI violations which will lead to problems
722when mixing LLVM output with code built with other compilers,
723particularly for C++ and floating-point programs.</li>
724
725<li>Vararg functions are not supported.</li>
726
727</ul>
728
729</div>
730
Chris Lattner98a493c2005-05-15 16:01:20 +0000[diff] [blame^]731<!-- ======================================================================= -->
732<div class="doc_subsection">
733 <a name="sparcv8">Known problems with the SPARC-V8 back-end</a>
734</div>
735
736<div class="doc_text">
737
738<ul>
739<li>Many features are still missing (e.g. support for 64-bit integer
740arithmetic).</li>
741
742<li>This backend needs to be updated to use the SelectionDAG instruction
743selection framework.</li>
744</ul>
745
746</div>
747
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]748<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]749<div class="doc_section">
750 <a name="additionalinfo">Additional Information</a>
751</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]752<!-- *********************************************************************** -->
753
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]754<div class="doc_text">
755
756<p>A wide variety of additional information is available on the LLVM web page,
Misha Brukman109d9e82005-03-30 19:14:24 +0000[diff] [blame]757including <a href="http://llvm.cs.uiuc.edu/docs/#maillist">mailing lists</a> and
758<a href="http://llvm.cs.uiuc.edu/pubs/">publications describing algorithms and
759components implemented in LLVM</a>. The web page also contains versions of the
760API documentation which is up-to-date with the CVS version of the source code.
761You can access versions of these documents specific to this release by going
762into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]763
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]764<p>If you have any questions or comments about LLVM, please feel free to contact
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]765us via the <a href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">mailing
766lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]767
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]768</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]769
770<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]771
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]772<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]773<address>
Misha Brukman38847d52003-12-21 22:53:21 +0000[diff] [blame]774 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]775 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
776 <a href="http://validator.w3.org/check/referer"><img
777 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
778
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]779 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]780 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]781</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]782
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]783</body>
784</html>