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Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]6 <title>LLVM 1.2 Release Notes</title>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]7</head>
8<body>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]9
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]10<div class="doc_title">
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]11 LLVM 1.2 Release Notes
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]12</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]13
14<ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]15 <li><a href="#intro">Introduction</a></li>
16 <li><a href="#whatsnew">What's New?</a></li>
17 <li><a href="#portability">Portability and Supported Platforms</a></li>
18 <li><a href="#install-instructions">Installation Instructions</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]19 <li><a href="#knownproblems">Known Problems</a>
20 <ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]21 <li><a href="#core">Known problems with the LLVM Core</a>
22 <li><a href="#c-fe">Known problems with the C Front-end</a>
23 <li><a href="#c++-fe">Known problems with the C++ Front-end</a>
24 <li><a href="#x86-be">Known problems with the X86 Back-end</a>
25 <li><a href="#sparc-be">Known problems with the Sparc Back-end</a>
26 <li><a href="#c-be">Known problems with the C back-end</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]27 </ul></li>
28 <li><a href="#additionalinfo">Additional Information</a></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]29</ol>
30
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]31<div class="doc_text">
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]32 <p><b>Written by the <a href="http://llvm.cs.uiuc.edu">LLVM team</a></b><p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]33</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]34
35<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]36<div class="doc_section">
37 <a name="intro">Introduction</a>
38</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]39<!-- *********************************************************************** -->
40
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]41<div class="doc_text">
42
43<p>This document contains the release notes for the LLVM compiler
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]44infrastructure, release 1.2. Here we describe the status of LLVM, including any
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]45known problems and bug fixes from the previous release. The most up-to-date
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]46version of this document can be found on the <a
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]47href="http://llvm.cs.uiuc.edu/releases/1.2/">LLVM 1.2 web site</a>. If you are
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]48not reading this on the LLVM web pages, you should probably go there because
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]49this document may be updated after the release.</p>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]50
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]51<p>For more information about LLVM, including information about potentially more
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]52current releases, please check out the <a href="http://llvm.cs.uiuc.edu">main
53web site</a>. If you have questions or comments, the <a
54href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]55list</a> is a good place to send them.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]56
Chris Lattner9e848092003-12-12 04:25:33 +0000[diff] [blame]57<p>Note that if you are reading this file from CVS, this document applies
58to the <i>next</i> release, not the current one. To see the release notes for
59the current or previous releases, see the <a
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]60href="http://llvm.cs.uiuc.edu/releases/">releases page</a>.</p>
61
62</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]63
64<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]65<div class="doc_section">
66 <a name="whatsnew">What's New?</a>
67</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]68<!-- *********************************************************************** -->
69
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]70<div class="doc_text">
71
Chris Lattnera39719f2004-02-25 16:36:51 +0000[diff] [blame]72<p>
73This is the third public release of the LLVM compiler infrastructure. This
74release incorporates several <a href="#newfeatures">new features</a> (including
75exception handling support for the native code generators, the start of a
76source-level debugger, and profile guided optimizer components), many <a
77href="#qualityofimp">speedups</a> and <a href="#codequality">code quality</a>
78improvements, documentation improvements, and a small collection of important <a
79href="bugfix">bug fixes</a>. Overall, this is our highest quality release to
80date, and we encourage you to upgrade if you are using LLVM 1.0 or 1.1.
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]81</p>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]82
Chris Lattnera39719f2004-02-25 16:36:51 +0000[diff] [blame]83<p><B> FIXME: UPDATE: </b>
84At this time, LLVM is known to correctly compile and run all C
Chris Lattner1124e2c2003-12-12 21:33:08 +0000[diff] [blame]85&amp; C++ SPEC CPU2000 benchmarks, the Olden benchmarks, and the Ptrdist
86benchmarks. It has also been used to compile <b>many</b> other programs. LLVM
87now also works with a broad variety of C++ programs, though it has still
Chris Lattnerde4afdc2004-02-08 22:23:33 +0000[diff] [blame]88received less testing than the C front-end.
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]89</p>
90
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]91<!--=========================================================================-->
92<div class="doc_subsubsection">
Chris Lattnera39719f2004-02-25 16:36:51 +0000[diff] [blame]93<a name="newfeatures">This release implements the following new features:</a>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]94</div>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]95
96<ol>
Chris Lattner95778a02004-02-08 21:20:42 +0000[diff] [blame]97<li><a href="SourceLevelDebugging.html">A new LLVM source-level debugger has been started.</a></li>
Chris Lattnera118ae12004-02-23 03:51:34 +0000[diff] [blame]98<li>LLVM 1.2 encodes bytecode files for large programs in 10-30% less space.</li>
99<li>LLVM can now feed profile information back into optimizers for Profile Guided Optimization, and includes a simple basic block reordering pass.</li>
100<li>The LLVM JIT lazily initializes global variables, reducing startup time for programs with lots of globals (like C++ programs).</li>
Chris Lattnera39719f2004-02-25 16:36:51 +0000[diff] [blame]101
102<li>The build and installation infrastructure in this release is dramatically
103improved. There is now an <a
104href="http://llvm.cs.uiuc.edu/PR105"><tt>autoconf/AutoRegen.sh</tt> script</a>
105that you can run to rebuild the <tt>configure</tt> script and its associated
106files as well as beta support for "<a
107href="http://llvm.cs.uiuc.edu/PR208">make</a> <a
108href="http://llvm.cs.uiuc.edu/PR220">install</a>" and <a
109href="http://llvm.cs.uiuc.edu/PR203">RPM package generation</a>.</li>
110
Chris Lattnera118ae12004-02-23 03:51:34 +0000[diff] [blame]111<li>The "tblgen" tool is <a href="TableGenFundamentals.html">now documented</a>.</li>
Alkis Evlogimenos4817e9c2004-02-27 05:26:23 +0000[diff] [blame]112<li>The LLVM code generator got a multitude of improvements:
113<ul>
114<li>It can now fold spill code into instructions on targets that support it.</li>
115<li>A generic machine code spiller/rewriter was added. It provides an API for
116global register allocators to eliminate virtual registers and add the
117appropriate spill code.</li>
118<li>The represenation of machine basic blocks got cleaned up and improved to
119allow easier development and more efficient implementation.</li>
120</ul>
121</li>
Chris Lattner1e1a78a2004-02-24 03:50:24 +0000[diff] [blame]122<li><a href="http://llvm.cs.uiuc.edu/PR253">LLVM now no longer depends on the boost library</a>.</li>
Chris Lattnera39719f2004-02-25 16:36:51 +0000[diff] [blame]123<li>The X86 backend now generates <b>substantially</b> better native code, and is faster.</li>
124<li>The C backend has been turned moved from the "llvm-dis" tool to the "llc"
125tool. You can activate it with "<tt>llc -march=c foo.bc -o foo.c</tt>".</li>
Chris Lattnerfd343b02004-02-26 08:02:57 +0000[diff] [blame]126<li>LLVM includes a new interprocedural optimization that marks global variables
127"constant" when they are provably never written to.</li>
Chris Lattner55ee0312003-11-19 22:05:38 +0000[diff] [blame]128</ol>
Chris Lattner0ef19062003-11-08 04:28:55 +0000[diff] [blame]129
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]130
131<!--=========================================================================-->
132<div class="doc_subsubsection">
133In this release, the following missing features were implemented:
134</div>
Chris Lattner0ef19062003-11-08 04:28:55 +0000[diff] [blame]135
136<ol>
Chris Lattner127215e2004-02-08 19:59:05 +0000[diff] [blame]137<li><a href="http://llvm.cs.uiuc.edu/PR16">Exception handling support in the X86
138&amp; Sparc native code generators</a></li>
Chris Lattner3a51be12004-02-14 04:12:41 +0000[diff] [blame]139<li>The C/C++ front-end now support the GCC <tt>__builtin_return_address</tt> and <tt>__builtin_frame_address</tt> extensions.</li>
Chris Lattner3fd82592004-02-23 03:36:36 +0000[diff] [blame]140<li><a href="http://llvm.cs.uiuc.edu/PR249">[X86] Missing cast from ULong -> Double, cast FP -> bool and support for -9223372036854775808</a></li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]141</ol>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]142
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]143
144<!--=========================================================================-->
145<div class="doc_subsubsection">
Chris Lattnera39719f2004-02-25 16:36:51 +0000[diff] [blame]146<a name="qualityofimp">In this release, the following Quality of Implementation issues were fixed:</a>
Chris Lattnere29ac162003-12-20 03:42:11 +0000[diff] [blame]147</div>
148
149<ol>
150
151<li><a href="http://llvm.cs.uiuc.edu/PR135">JIT should lazily initialize global variables</a></li>
Chris Lattneref56a192003-12-20 10:29:02 +0000[diff] [blame]152<li><a href="http://llvm.cs.uiuc.edu/PR192">[X86] X86 Backend never releases memory for machine code structures</a></li>
Chris Lattner71f0a822003-12-23 23:50:31 +0000[diff] [blame]153<li><a href="http://llvm.cs.uiuc.edu/PR196">[vmcore] OpaqueType objects memory leak</a></li>
Chris Lattner1abc87e2004-01-08 17:20:50 +0000[diff] [blame]154<li><a href="http://llvm.cs.uiuc.edu/PR182">[llvmgcc] C front-end does not compile "extern inline" into linkonce</a></li>
Chris Lattner23632f12004-01-15 17:59:29 +0000[diff] [blame]155<li><a href="http://llvm.cs.uiuc.edu/PR73">Bytecode format inconsistent</a></li>
Chris Lattner913a9342004-02-05 17:31:37 +0000[diff] [blame]156<li><a href="http://llvm.cs.uiuc.edu/PR209">[loadvn/inline/scalarrepl] Slow optimizations with extremely large basic blocks</a></li>
Chris Lattnera50c4ba2004-02-09 21:16:16 +0000[diff] [blame]157<li><a href="http://llvm.cs.uiuc.edu/PR224">[asmparser] Really slow parsing of types with complex upreferences</a></li>
Chris Lattnerd6a185f2004-02-15 05:47:37 +0000[diff] [blame]158<li><a href="http://llvm.cs.uiuc.edu/PR205">[llvmgcc] C front-end does not emit 'zeroinitializer' when possible</a></li>
Chris Lattnera39719f2004-02-25 16:36:51 +0000[diff] [blame]159<li><a href="http://llvm.cs.uiuc.edu/PR233">[llvmgcc] Structure copies result in a LOT of code</a></li>
Chris Lattner9f3c7f72004-02-15 06:00:04 +0000[diff] [blame]160<li><a href="http://llvm.cs.uiuc.edu/PR239">LLVM is now much more memory efficient when handling large zero initialized arrays</a></li>
Chris Lattnere29ac162003-12-20 03:42:11 +0000[diff] [blame]161</ol>
162
163<!--=========================================================================-->
164<div class="doc_subsubsection">
Chris Lattnera39719f2004-02-25 16:36:51 +0000[diff] [blame]165In this release, the following build problems were fixed:
Brian Gaeke6b31beb2004-01-16 21:55:04 +0000[diff] [blame]166</div>
167
168<ol>
169<li><a href="http://llvm.cs.uiuc.edu/PR210">[build] Makefiles break if C frontend target string has unexpected value</a></li>
John Criswell6b153402004-01-26 21:03:54 +0000[diff] [blame]170<li><a href="http://llvm.cs.uiuc.edu/PR214">[build] hard-wired assumption that shared-library extension is ".so"</a></li>
Chris Lattner3e0bd312004-02-03 22:59:56 +0000[diff] [blame]171<li><A href="http://llvm.cs.uiuc.edu/PR222">make tools-only doesn't make lib/Support</a></li>
Brian Gaeke6b31beb2004-01-16 21:55:04 +0000[diff] [blame]172</ol>
173
174<!--=========================================================================-->
175<div class="doc_subsubsection">
Chris Lattnera39719f2004-02-25 16:36:51 +0000[diff] [blame]176<a name="codequality">In this release, the following Code Quality issues were fixed:</a>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]177</div>
Chris Lattner89ca2b82003-10-27 17:06:39 +0000[diff] [blame]178
179<ol>
Chris Lattner9e259062003-12-19 06:31:56 +0000[diff] [blame]180<li><a href="http://llvm.cs.uiuc.edu/PR187">[loopsimplify] Many pointless phi nodes are created</a></li>
Chris Lattner1fda3702004-02-15 00:23:15 +0000[diff] [blame]181<li><a href="http://llvm.cs.uiuc.edu/PR237">[x86] wierd stack/frame pointer manipulation</a></li>
Chris Lattnera39719f2004-02-25 16:36:51 +0000[diff] [blame]182
183<li>The X86 backend now generate <tt>fchs</tt> to negate floating point numbers,
184compiles memcpy() into the <tt>rep movs</tt> instruction, and makes much better
185use of powerful addressing modes and instructions.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]186</ol>
Chris Lattner89ca2b82003-10-27 17:06:39 +0000[diff] [blame]187
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]188
189<!--=========================================================================-->
190<div class="doc_subsubsection">
Chris Lattnera39719f2004-02-25 16:36:51 +0000[diff] [blame]191<a name="bugfix">In this release, the following bugs in the previous release were fixed:</a>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]192</div>
193
194<p>Bugs in the LLVM Core:</p>
Chris Lattner47ad72c2003-10-07 21:38:31 +0000[diff] [blame]195
196<ol>
Misha Brukmanad643852003-12-15 22:48:12 +0000[diff] [blame]197<li><a href="http://llvm.cs.uiuc.edu/PR179">[licm] LICM promotes volatile memory
198locations to registers</a></li>
Chris Lattner5b7142a2003-12-18 08:16:25 +0000[diff] [blame]199<li><a href="http://llvm.cs.uiuc.edu/PR191">[licm] Memory read after free causes
200infrequent crash</a></li>
Chris Lattner5de946f2003-12-22 04:06:24 +0000[diff] [blame]201<li><a href="http://llvm.cs.uiuc.edu/PR194">[indvars] Induction variable
202canonicalization always makes 32-bit indvars</a></li>
Chris Lattner0cbdd972003-12-22 23:56:37 +0000[diff] [blame]203<li><a href="http://llvm.cs.uiuc.edu/PR193">[constantmerge] Merging globals can
204cause use of invalid pointers!</a></li>
Chris Lattnerae3664b2004-01-20 19:16:50 +0000[diff] [blame]205<li><a href="http://llvm.cs.uiuc.edu/PR212">[bcreader] Bytecode reader misreads 'long -9223372036854775808'!</a></li>
Chris Lattner56e67052004-02-09 21:22:51 +0000[diff] [blame]206<li><a href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=174">Tail duplication does not update SSA form correctly.</a></li>
Chris Lattnerc8a35812004-02-01 22:52:12 +0000[diff] [blame]207<li><a href="http://llvm.cs.uiuc.edu/PR218">VMCore mishandles double -0.0</a></li>
Chris Lattner02babb82004-02-02 19:40:06 +0000[diff] [blame]208<li><a href="http://llvm.cs.uiuc.edu/PR219">[X86] X86 backend code generates -0.0 as +0.0</a></li>
Chris Lattner741f6b42004-02-05 21:16:42 +0000[diff] [blame]209<li><a href="http://llvm.cs.uiuc.edu/PR223">[loopsimplify] Loopsimplify incorrectly updates dominator information</a></li>
Chris Lattner95778a02004-02-08 21:20:42 +0000[diff] [blame]210<li><a href="http://llvm.cs.uiuc.edu/PR225">[pruneeh] -pruneeh pass removes invoke instructions it shouldn't</a></li>
Chris Lattner964b0d82004-02-10 05:19:54 +0000[diff] [blame]211<li><a href="http://llvm.cs.uiuc.edu/PR228">[sparc] Boolean constants are emitted as true and false</a></li>
Brian Gaeke3a9ec192004-02-26 00:08:25 +0000[diff] [blame]212<li><a href="http://llvm.cs.uiuc.edu/PR234">[interpreter] va_list values silently corrupted by function calls</a></li>
Chris Lattnerbd8c4562004-02-13 16:40:24 +0000[diff] [blame]213<li><a href="http://llvm.cs.uiuc.edu/PR235">Tablegen aborts on errors</a></li>
Chris Lattner4b2b6842004-02-13 17:03:01 +0000[diff] [blame]214<li><a href="http://llvm.cs.uiuc.edu/PR236">[inliner] Error inlining intrinsic calls into invoke instructions</a></li>
Chris Lattner95026582004-02-17 22:00:39 +0000[diff] [blame]215<li><a href="http://llvm.cs.uiuc.edu/PR245">Linking weak and strong global variables is dependent on link order</a></li>
John Criswell412926e2004-02-26 23:13:34 +0000[diff] [blame]216<li><a href="http://llvm.cs.uiuc.edu/PR258">Variables used to define non-printable FP constants are externally visible</a></li>
217<li><a href="http://llvm.cs.uiuc.edu/PR259">CBE gives linkonce functions wrong linkage semantics</a></li>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]218</ol>
219
220
Chris Lattner56e67052004-02-09 21:22:51 +0000[diff] [blame]221
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]222<p>Bugs in the C/C++ front-end:</p>
223
224<ol>
Misha Brukmanad643852003-12-15 22:48:12 +0000[diff] [blame]225<li><a href="http://llvm.cs.uiuc.edu/PR186">Need weak linkage on memory
226management functions in libc runtime to allow them to be overriden</a></li>
Chris Lattner1abc87e2004-01-08 17:20:50 +0000[diff] [blame]227<li><a href="http://llvm.cs.uiuc.edu/PR202">[llvm-gcc] asserts when an extern inline function is redefined</a></li>
Chris Lattnerc43f91f2004-01-12 05:15:04 +0000[diff] [blame]228<li><a href="http://llvm.cs.uiuc.edu/PR204">[llvmg++] Dynamically initialized constants cannot be marked 'constant'</a></li>
Chris Lattner55d14de2004-02-02 17:48:56 +0000[diff] [blame]229<li><a href="http://llvm.cs.uiuc.edu/PR216">[llvmgcc] floating-point unary minus is incorrect for +0.0</a></li>
Chris Lattneracc00bc2004-02-03 08:03:41 +0000[diff] [blame]230<li><a href="http://llvm.cs.uiuc.edu/PR221">[llvm-gcc] miscompilation of 'X = Y = Z' with aggregate values</a></li>
Chris Lattner98328742004-02-20 17:41:35 +0000[diff] [blame]231<li><a href="http://llvm.cs.uiuc.edu/PR244">[llvm-gcc] miscompilation when a function is re-declared as static</a></li>
Chris Lattnereacf9272004-03-08 04:55:45 +0000[diff] [blame]232<li><a href="http://llvm.cs.uiuc.edu/PR272">[llvmgcc] Invalid code created for complex division operation</a></li>
Chris Lattner15f0a872004-03-09 00:40:49 +0000[diff] [blame]233<li><a href="http://llvm.cs.uiuc.edu/PR268">[llvmgcc] Incorrect code generation for pointer subtraction</a></li>
Chris Lattner0fe65a82004-03-09 00:59:15 +0000[diff] [blame^]234<li><a href="http://llvm.cs.uiuc.edu/PR261">[llvmg++] Crash assigning pointers-to-members with casted types</a></li>
Chris Lattnera5099962003-12-06 20:22:41 +0000[diff] [blame]235</ol>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]236
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]237</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]238
239<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]240<div class="doc_section">
241 <a name="portability">Portability and Supported Platforms</a>
242</div>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]243<!-- *********************************************************************** -->
244
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]245<div class="doc_text">
246
247<p>LLVM has been extensively tested on Intel and AMD machines running Red
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]248Hat Linux and FreeBSD. It has also been tested on Sun UltraSPARC workstations running Solaris 8.
John Criswellbb1bad52003-12-12 19:54:20 +0000[diff] [blame]249Additionally,
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]250LLVM works on Mac OS X 10.3 and above, but only with the C backend or
Chris Lattner9e848092003-12-12 04:25:33 +0000[diff] [blame]251interpreter (no native backend for the PowerPC is available yet).
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]252The core LLVM infrastructure uses "autoconf" for portability, so hopefully we
Chris Lattner3e2959e2003-11-08 05:22:09 +0000[diff] [blame]253work on more platforms than that. However, it is likely that we
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]254missed something and that minor porting is required to get LLVM to work on
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]255new platforms. We welcome portability patches and error messages.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]256
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]257</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]258
259<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]260<div class="doc_section">
261 <a name="knownproblems">Known Problems</a>
262</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]263<!-- *********************************************************************** -->
264
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]265<div class="doc_text">
266
267<p>This section contains all known problems with the LLVM system, listed by
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]268component. As new problems are discovered, they will be added to these
Chris Lattner5eccca42003-12-12 21:22:16 +0000[diff] [blame]269sections. If you run into a problem, please check the <a
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]270href="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]271there isn't already one.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]272
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]273</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]274
275<!-- _______________________________________________________________________ -->
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]276<!--
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]277</ul><h4><a name="portability"><hr size=0>Portability Problems</h4><ul>
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]278-->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]279
280
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]281<!-- ======================================================================= -->
282<div class="doc_subsection">
283 <a name="core">Known problems with the LLVM Core</a>
284</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]285
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]286<div class="doc_text">
287
288<ul>
289
290<li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not
291work.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]292
293<li>The JIT does not use mutexes to protect its internal data structures. As
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]294such, execution of a threaded program could cause these data structures to be
295corrupted.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]296
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]297<li>It is not possible to <tt>dlopen</tt> an LLVM bytecode file in the JIT.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]298
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]299<li>Linking in static archive files (.a files) is very slow (there is no symbol
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]300table in the archive).</li>
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]301
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]302<li><a href="http://llvm.cs.uiuc.edu/PR82">LLVM cannot handle structures with
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]303more than 256 elements</a>.</li>
304
Chris Lattner2e6fcaf2004-02-15 23:09:07 +0000[diff] [blame]305<li>The gccld program <a href="http://llvm.cs.uiuc.edu/PR139">does not link objects/archives in the order specified on the command line.</a></li>
306
307<li><a href="http://llvm.cs.uiuc.edu/PR240">The lower-invoke pass does not mark
308values live across a setjmp as volatile</a>. This missing feature only effects
309targets whose setjmp/longjmp libraries do not save and restore the entire
310register file.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]311</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]312</div>
313
314<!-- ======================================================================= -->
315<div class="doc_subsection">
316 <a name="c-fe">Known problems with the C front-end</a>
317</div>
Chris Lattner47588f92003-10-02 05:07:23 +0000[diff] [blame]318
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]319<!-- _______________________________________________________________________ -->
Chris Lattnerb40efb32003-12-14 05:03:43 +0000[diff] [blame]320<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]321
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]322<div class="doc_text">
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]323<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]324<li>C99 Variable sized arrays do not release stack memory when they go out of
325 scope. Thus, the following program may run out of stack space:
326<pre>
327 for (i = 0; i != 1000000; ++i) {
328 int X[n];
329 foo(X);
330 }
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]331</pre></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]332
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]333<li>
334Initialization of global union variables can only be done
335<a href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=162">with the largest
336union member</a>.
337</li>
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]338</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]339</div>
340
341<!-- _______________________________________________________________________ -->
342<div class="doc_subsubsection">
343 Notes
344</div>
345
346<div class="doc_text">
347
348<ul>
349
350<li>Inline assembly is not yet supported.</li>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]351
352<li>"long double" is transformed by the front-end into "double". There is no
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]353support for floating point data types of any size other than 32 and 64
354bits.</li>
355
356<li>The following Unix system functionality has not been tested and may not
357work:
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]358 <ol>
359 <li><tt>sigsetjmp</tt>, <tt>siglongjmp</tt> - These are not turned into the
360 appropriate <tt>invoke</tt>/<tt>unwind</tt> instructions. Note that
361 <tt>setjmp</tt> and <tt>longjmp</tt> <em>are</em> compiled correctly.
362 <li><tt>getcontext</tt>, <tt>setcontext</tt>, <tt>makecontext</tt>
363 - These functions have not been tested.
364 </ol></li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]365
366<li>Although many GCC extensions are supported, some are not. In particular,
367 the following extensions are known to <b>not be</b> supported:
368 <ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]369 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Local-Labels.html#Local%20Labels">Local Labels</a>: Labels local to a block.</li>
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]370 <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]371 <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>
372 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Constructing-Calls.html#Constructing%20Calls">Constructing Calls</a>: Dispatching a call to another function.</li>
373 <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]374 <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]375 <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>
376 <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]377 <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>
378 <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>
379 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables.</li>
380 <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]381 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]382
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]383 <p>The following GCC extensions are <b>partially</b> supported. An ignored
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]384 attribute means that the LLVM compiler ignores the presence of the attribute,
385 but the code should still work. An unsupported attribute is one which is
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]386 ignored by the LLVM compiler and will cause a different interpretation of
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]387 the program.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]388
389 <ol>
390 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html#Variable%20Length">Variable Length</a>:
391 Arrays whose length is computed at run time.<br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]392 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]393
394 <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]395
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]396 Declaring that functions have no side effects or that they can never
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]397 return.<br>
398
399 <b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
400 <tt>constructor</tt>, <tt>destructor</tt>, <tt>unused</tt>,
401 <tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
402
403 <b>Ignored:</b> <tt>noreturn</tt>, <tt>noinline</tt>,
404 <tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
405 <tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
406
407 <b>Unsupported:</b> <tt>used</tt>, <tt>section</tt>, <tt>alias</tt>,
408 <tt>visibility</tt>, <tt>regparm</tt>, <tt>stdcall</tt>,
409 <tt>fastcall</tt>, all other target specific attributes</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]410
411 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html#Variable%20Attributes">Variable Attributes</a>:
412 Specifying attributes of variables.<br>
413 <b>Supported:</b> <tt>cleanup</tt>, <tt>common</tt>, <tt>nocommon</tt>,
414 <tt>deprecated</tt>, <tt>transparent_union</tt>,
415 <tt>unused</tt>, <tt>weak</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]416
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]417 <b>Unsupported:</b> <tt>aligned</tt>, <tt>mode</tt>, <tt>packed</tt>,
418 <tt>section</tt>, <tt>shared</tt>, <tt>tls_model</tt>,
419 <tt>vector_size</tt>, <tt>dllimport</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]420 <tt>dllexport</tt>, all target specific attributes.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]421
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]422 <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]423 <b>Supported:</b> <tt>transparent_union</tt>, <tt>unused</tt>,
Misha Brukmanc4b7bee2003-12-12 04:37:31 +0000[diff] [blame]424 <tt>deprecated</tt>, <tt>may_alias</tt><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]425
426 <b>Unsupported:</b> <tt>aligned</tt>, <tt>packed</tt>,
427 all target specific attributes.</li>
428
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]429 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html#Other%20Builtins">Other Builtins</a>:
430 Other built-in functions.<br>
431 We support all builtins which have a C language equivalent (e.g.,
432 <tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
433 <tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]434 <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt> (ignored).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]435
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]436 </ol>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]437
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]438 <p>The following extensions <b>are</b> known to be supported:</p>
439
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]440 <ol>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]441 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
442 <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>
443 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
444 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
445 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
446 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
447 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Hex-Floats.html#Hex%20Floats">Hex Floats</a>:Hexadecimal floating-point constants.</li>
448 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html#Zero%20Length">Zero Length</a>: Zero-length arrays.</li>
449 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Empty-Structures.html#Empty%20Structures">Empty Structures</a>: Structures with no members.</li>
450 <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>
451 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Escaped-Newlines.html#Escaped%20Newlines">Escaped Newlines</a>: Slightly looser rules for escaped newlines.</li>
452 <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]453 <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]454 <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]455 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Compound-Literals.html#Compound%20Literals">Compound Literals</a>: Compound literals give structures, unions,
456or arrays as values.</li>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]457 <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]458 <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]459 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
460 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
461 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
462 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized.</li>
463 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
464 <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>
465 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
466 <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Inline.html#Inline">Inline</a>: Defining inline functions (as fast as macros).</li>
467 <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>
468 <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>
469 <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]470 <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]471 <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>
472 <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]473 </ol></li>
474
475</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]476
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]477<p>If you run into GCC extensions which have not been included in any of these
478lists, please let us know (also including whether or not they work).</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]479
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]480</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]481
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]482<!-- ======================================================================= -->
483<div class="doc_subsection">
484 <a name="c++-fe">Known problems with the C++ front-end</a>
485</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]486
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]487<div class="doc_text">
488
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]489<p>For this release, the C++ front-end is considered to be fully functional but
Chris Lattner9e848092003-12-12 04:25:33 +0000[diff] [blame]490has not been tested as thoroughly as the C front-end. It has been tested and
491works for a number of non-trivial programs, but there may be lurking bugs.
492Please report any bugs or problems.</p>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]493
494</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]495
496<!-- _______________________________________________________________________ -->
Chris Lattner3a51be12004-02-14 04:12:41 +0000[diff] [blame]497<div class="doc_subsubsection">Bugs</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]498
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]499<div class="doc_text">
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]500
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]501<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]502<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]503 front-end</a>.</li>
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]504</ul>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]505</div>
506
507<!-- _______________________________________________________________________ -->
508<div class="doc_subsubsection">
509 Notes
510</div>
511
512<div class="doc_text">
513
514<ul>
Chris Lattnere01fcfb2003-10-27 18:30:37 +0000[diff] [blame]515
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]516<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
517parser is significantly more standards compliant (and picky) than prior GCC
518versions. For more information, see the C++ section of the <a
Chris Lattner9e848092003-12-12 04:25:33 +0000[diff] [blame]519href="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]520
521<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]522 performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]523 function and in the <tt>setjmp</tt> receiver function may not be run.
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]524 Objects in intervening stack frames will be destroyed, however (which is
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]525 better than most compilers).</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]526
Chris Lattner19092612003-10-02 16:38:05 +0000[diff] [blame]527<li>The LLVM C++ front-end follows the <a
528 href="http://www.codesourcery.com/cxx-abi">Itanium C++ ABI</a>.
529 This document, which is not Itanium specific, specifies a standard for name
530 mangling, class layout, v-table layout, RTTI formats, and other C++
531 representation issues. Because we use this API, code generated by the LLVM
532 compilers should be binary compatible with machine code generated by other
533 Itanium ABI C++ compilers (such as G++, the Intel and HP compilers, etc).
534 <i>However</i>, the exception handling mechanism used by LLVM is very
535 different from the model used in the Itanium ABI, so <b>exceptions will not
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]536 interact correctly</b>. </li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]537
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]538</ul>
Chris Lattnerfcc54b32003-10-07 22:14:37 +0000[diff] [blame]539
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]540</div>
541
542<!-- ======================================================================= -->
543<div class="doc_subsection">
544 <a name="x86-be">Known problems with the X86 back-end</a>
545</div>
546
547<div class="doc_text">
548
549<ul>
Chris Lattnerde4afdc2004-02-08 22:23:33 +0000[diff] [blame]550<li>None so far.
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]551</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]552
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]553</div>
554
555<!-- ======================================================================= -->
556<div class="doc_subsection">
557 <a name="sparc-be">Known problems with the Sparc back-end</a>
558</div>
559
560<div class="doc_text">
561
562<ul>
Chris Lattnerde4afdc2004-02-08 22:23:33 +0000[diff] [blame]563<li>None so far.
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]564</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]565
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]566</div>
567
568<!-- ======================================================================= -->
569<div class="doc_subsection">
570 <a name="c-be">Known problems with the C back-end</a>
571</div>
572
573<div class="doc_text">
574
575<ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]576
577<li>The C back-end produces code that violates the ANSI C Type-Based Alias
578Analysis rules. As such, special options may be necessary to compile the code
579(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]580problem probably cannot be fixed.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]581
Chris Lattnere84843b2003-10-20 19:05:03 +0000[diff] [blame]582<li><a href="http://llvm.cs.uiuc.edu/PR33">Initializers for global variables</a>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]583cannot include special floating point numbers like Not-A-Number or
584Infinity.</li>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]585
Chris Lattner2855ecd2003-11-04 20:06:53 +0000[diff] [blame]586<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]587supported</a>. This should not affect LLVM produced by the C or C++
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]588frontends.</li>
Chris Lattner2af46052003-10-24 04:03:19 +0000[diff] [blame]589
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]590</ul>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]591
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]592</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]593
594<!-- *********************************************************************** -->
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]595<div class="doc_section">
596 <a name="additionalinfo">Additional Information</a>
597</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]598<!-- *********************************************************************** -->
599
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]600<div class="doc_text">
601
602<p>A wide variety of additional information is available on the LLVM web page,
John Criswelld000e1d2003-12-18 16:43:17 +0000[diff] [blame]603including mailing lists and publications describing algorithms and components
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]604implemented in LLVM. The web page also contains versions of the API
605documentation which is up-to-date with the CVS version of the source code. You
606can access versions of these documents specific to this release by going into
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]607the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]608
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]609<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]610us via the <a href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">mailing
611lists</a>.</p>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]612
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]613</div>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]614
615<!-- *********************************************************************** -->
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]616
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]617<hr>
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]618<address>
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623
Misha Brukmane0c891c2003-11-22 01:00:11 +0000[diff] [blame]624 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]625 Last modified: $Date$
Misha Brukman2061e892003-11-22 01:23:39 +0000[diff] [blame]626</address>
Chris Lattner79c3fe12003-10-02 04:57:28 +0000[diff] [blame]627
Misha Brukman500bc302003-11-22 00:38:41 +0000[diff] [blame]628</body>
629</html>