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Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
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3<html>
4<head>
5 <title>Open LLVM Projects</title>
6 <link rel="stylesheet" href="llvm.css" type="text/css">
7</head>
8<body>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]9
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]10<div class="doc_title">
11 Open LLVM Projects
12</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]13
14<ul>
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]15 <li><a href="#what">What is this?</a></li>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]16 <li><a href="#improving">Improving the current system</a>
17 <ol>
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]18 <li><a href="#glibc">Port glibc to LLVM</a></li>
19 <li><a href="#NightlyTest">Improving the Nightly Tester</a></li>
20 <li><a href="#programs">Compile programs with the LLVM Compiler</a></li>
21 <li><a href="#llvm_ir">Extend the LLVM intermediate representation</a></li>
22 <li><a href="#misc_imp">Miscellaneous Improvements</a></li>
23 </ol></li>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]24
25 <li><a href="#new">Adding new capabilities to LLVM</a>
26 <ol>
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]27 <li><a href="#pointeranalysis">Pointer and Alias Analysis</a></li>
28 <li><a href="#profileguided">Profile Guided Optimization</a></li>
29 <li><a href="#xforms">New Transformations and Analyses</a></li>
30 <li><a href="#x86be">X86 Back-end Improvements</a></li>
31 <li><a href="#misc_new">Miscellaneous Additions</a></li>
32 </ol></li>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]33</ul>
34
Chris Lattner97d49ef2004-05-23 21:06:21 +0000[diff] [blame^]35<div class="doc_author">
36 <p>Written by the <a href="http://llvm.cs.uiuc.edu/">LLVM Team</a></p>
37</div>
38
39
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]40<!-- *********************************************************************** -->
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]41<div class="doc_section">
42 <a name="what">What is this?</a>
43</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]44<!-- *********************************************************************** -->
45
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]46<div class="doc_text">
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]47
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]48<p>This document is meant to be a sort of "big TODO list" for LLVM. Each
49project in this document is something that would be useful for LLVM to have, and
50would also be a great way to get familiar with the system. Some of these
51projects are small and self-contained, which may be implemented in a couple of
52days, others are larger. Several of these projects may lead to interesting
53research projects in their own right. In any case, we welcome all
54contributions.</p>
55
56<p>If you are thinking about tackling one of these projects, please send a mail
57to the <a href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]58Developer's</a> mailing list, so that we know the project is being worked on.
59Additionally this is a good way to get more information about a specific project
Alkis Evlogimenos45ff0272004-03-11 02:50:35 +0000[diff] [blame]60or to suggest other projects to add to this page.
61</p>
62
Misha Brukman836db502004-05-12 18:57:54 +0000[diff] [blame]63<p>The projects in this page are open-ended. More specific projects are
64filed as unassigned enhancements in the <a href="http://llvm.cs.uiuc.edu/bugs/">
Chris Lattner9f57b182004-05-23 20:29:35 +0000[diff] [blame]65LLVM bug tracker</a>. See the <a href="http://llvm.cs.uiuc.edu/bugs/buglist.cgi?keywords_type=allwords&amp;keywords=&amp;bug_status=NEW&amp;bug_status=ASSIGNED&amp;bug_status=REOPENED&amp;bug_severity=enhancement&amp;emailassigned_to1=1&amp;emailtype1=substring&amp;email1=unassigned">list of currently outstanding issues</a> if you wish to help improve LLVM.</p>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]66
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]67</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]68
69<!-- *********************************************************************** -->
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]70<div class="doc_section">
71 <a name="improving">Improving the current system</a>
72</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]73<!-- *********************************************************************** -->
74
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]75<div class="doc_text">
76
77<p>Improvements to the current infrastructure are always very welcome and tend
78to be fairly straight-forward to implement. Here are some of the key areas that
79can use improvement...</p>
80
81</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]82
83<!-- ======================================================================= -->
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]84<div class="doc_subsection">
85 <a name="glibc">Port glibc to LLVM</a>
86</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]87
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]88<div class="doc_text">
89
90<p>It would be very useful to <a
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]91href="http://www.gnu.org/software/libc/porting.html">port</a> <a
92href="http://www.gnu.org/software/glibc/">glibc</a> to LLVM. This would allow a
93variety of interprocedural algorithms to be much more effective in the face of
94library calls. The most important pieces to port are things like the string
95library and the <tt>stdio</tt> related functions... low-level system calls like
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]96'<tt>read</tt>' should stay unimplemented in LLVM.</p>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]97
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]98</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]99
100<!-- ======================================================================= -->
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]101<div class="doc_subsection">
102 <a name="NightlyTest">Improving the Nightly Tester</a>
103</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]104
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]105<div class="doc_text">
106
107<p>The <a href="/testresults/">Nightly Tester</a> is a simple perl script
108(located in <tt>utils/NightlyTest.pl</tt>) which runs every night to generate a
109daily report. It could use the following improvements:</p>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]110
111<ol>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]112<li>Regression tests - We should run the regression tests in addition to the
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]113 program tests...</li>
114</ol>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]115
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]116</div>
Chris Lattner1b360042003-02-07 19:25:35 +0000[diff] [blame]117
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]118<!-- ======================================================================= -->
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]119<div class="doc_subsection">
120 <a name="programs">Compile programs with the LLVM Compiler</a>
121</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]122
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]123<div class="doc_text">
124
125<p>We are always looking for new testcases and benchmarks for use with LLVM. In
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]126particular, it is useful to try compiling your favorite C source code with LLVM.
127If it doesn't compile, try to figure out why or report it to the <a
128href="http://mail.cs.uiuc.edu/pipermail/llvmbugs/">llvm-bugs</a> list. If you
129get the program to compile, it would be extremely useful to convert the build
130system to be compatible with the LLVM Programs testsuite so that we can check it
Chris Lattner1b360042003-02-07 19:25:35 +0000[diff] [blame]131into CVS and the automated tester can use it to track progress of the
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]132compiler.</p>
Chris Lattner1b360042003-02-07 19:25:35 +0000[diff] [blame]133
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]134<p>When testing a code, try running it with a variety of optimizations, and with
135all the back-ends: CBE, llc, and lli.</p>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]136
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]137</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]138
139<!-- ======================================================================= -->
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]140<div class="doc_subsection">
141 <a name="llvm_ir">Extend the LLVM intermediate representation</a>
142</div>
143
144<div class="doc_text">
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]145
146<ol>
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]147<li>Add support for platform-independent prefetch support. The GCC <a
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]148 href="http://gcc.gnu.org/projects/prefetch.html">prefetch project</a> page
149 has a good survey of the prefetching capabilities of a variety of modern
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]150 processors.</li>
151
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]152</ol>
153
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]154</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]155
156<!-- ======================================================================= -->
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]157<div class="doc_subsection">
158 <a name="misc_imp">Miscellaneous Improvements</a>
159</div>
160
161<div class="doc_text">
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]162
163<ol>
Chris Lattner8bde96f2003-05-06 20:47:11 +0000[diff] [blame]164<li>Someone needs to look into getting the <tt>ranlib</tt> tool to index LLVM
165 bytecode files, so that linking in .a files is not hideously slow. They
166 would also then have to implement the reader for this index in
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]167 <tt>gccld</tt>.</li>
Chris Lattner8bde96f2003-05-06 20:47:11 +0000[diff] [blame]168
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]169<li>Rework the PassManager to be more flexible</li>
170
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]171<li>Some transformations and analyses only work on reducible flow graphs. It
172would be nice to have a transformation which could be "required" by these passes
173which makes irreducible graphs reducible. This can easily be accomplished
174through code duplication. See <a
175href="http://citeseer.nj.nec.com/janssen97making.html">Making Graphs Reducible
176with Controlled Node Splitting</a> and perhaps <a
177href="http://doi.acm.org/10.1145/262004.262005">Nesting of Reducible and
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]178Irreducible Loops</a>.</li>
179
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]180</ol>
181
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]182</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]183
184<!-- *********************************************************************** -->
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]185<div class="doc_section">
186 <a name="new">Adding new capabilities to LLVM</a>
187</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]188<!-- *********************************************************************** -->
189
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]190<div class="doc_text">
191
Brian Gaeke2d261352004-04-07 15:31:23 +0000[diff] [blame]192<p>Sometimes creating new things is more fun than improving existing things.
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]193These projects tend to be more involved and perhaps require more work, but can
194also be very rewarding.</p>
195
196</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]197
198<!-- ======================================================================= -->
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]199<div class="doc_subsection">
200 <a name="pointeranalysis">Pointer and Alias Analysis</a>
201</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]202
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]203<div class="doc_text">
204
205<p>We have a <a href="AliasAnalysis.html">strong base for development</a> of
206both pointer analysis based optimizations as well as pointer analyses
207themselves. It seems natural to want to take advantage of this...</p>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]208
209<ol>
210<li>Implement a flow-sensitive context-sensitive alias analysis algorithm<br>
211 - Pick one of the somewhat efficient algorithms, but strive for maximum
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]212 precision</li>
213
Chris Lattnerf56703b2003-06-25 14:31:06 +0000[diff] [blame]214<li>Implement a flow-sensitive context-insensitive alias analysis algorithm<br>
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]215 - Just an efficient local algorithm perhaps?</li>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]216
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]217<li>Implement alias-analysis-based optimizations:
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]218 <ul>
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]219 <li>Dead store elimination</li>
220 <li>...</li>
221 </ul></li>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]222</ol>
223
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]224</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]225
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]226<!-- ======================================================================= -->
227<div class="doc_subsection">
228 <a name="profileguided">Profile Guided Optimization</a>
229</div>
230
231<div class="doc_text">
232
Chris Lattnera5422e42004-03-08 22:29:35 +0000[diff] [blame]233<p>We now have a unified infrastructure for writing profile-guided
234transformations, which will work either at offline-compile-time or in the JIT,
235but we don't have many transformations. We would welcome new profile-guided
236transformations as well as improvements to the current profiling system.
237</p>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]238
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]239<p>Ideas for profile guided transformations:</p>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]240
241<ol>
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]242<li>Superblock formation (with many optimizations)</li>
243<li>Loop unrolling/peeling</li>
244<li>Profile directed inlining</li>
245<li>Code layout</li>
246<li>...</li>
247</ol>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]248
Chris Lattnera5422e42004-03-08 22:29:35 +0000[diff] [blame]249<p>Improvements to the existing support:</p>
250
251<ol>
252<li>The current block and edge profiling code that gets inserted is very simple
253and inefficient. Through the use of control-dependence information, many fewer
254counters could be inserted into the code. Also, if the execution count of a
255loop is known to be a compile-time or runtime constant, all of the counters in
256the loop could be avoided.</li>
257
258<li>You could implement one of the "static profiling" algorithms which analyze a
259piece of code an make educated guesses about the relative execution frequencies
260of various parts of the code.</li>
261
262<li>You could add path profiling support, or adapt the existing LLVM path
263profiling code to work with the generic profiling interfaces.</li>
264</ol>
265
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]266</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]267
268<!-- ======================================================================= -->
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]269<div class="doc_subsection">
270 <a name="xforms">New Transformations and Analyses</a>
271</div>
272
273<div class="doc_text">
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]274
275<ol>
276<li>Implement a Dependence Analysis Infrastructure<br>
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]277 - Design some way to represent and query dep analysis</li>
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]278<li>Implement a strength reduction pass</li>
279<li>Value range propagation pass</li>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]280</ol>
281
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]282</div>
283
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]284<!-- ======================================================================= -->
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]285<div class="doc_section">
286 <a name="x86be">X86 Back-end Improvements</a>
287</div>
288
289<div class="doc_text">
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]290
291<ol>
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]292<li>Implement a better instruction selector</li>
Chris Lattner99df25f2003-04-28 03:42:31 +0000[diff] [blame]293<li>Implement support for the "switch" instruction without requiring the
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]294 lower-switches pass.</li>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]295</ol>
296
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]297</div>
298
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]299<!-- ======================================================================= -->
Misha Brukman3497ae92004-03-11 21:26:29 +0000[diff] [blame]300<div class="doc_section">
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]301 <a name="misc_new">Miscellaneous Additions</a>
302</div>
303
304<div class="doc_text">
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]305
306<ol>
Brian Gaeke2d261352004-04-07 15:31:23 +0000[diff] [blame]307<li>Port the <A HREF="http://www-sop.inria.fr/mimosa/fp/Bigloo/">Bigloo</A>
308Scheme compiler, from Manuel Serrano at INRIA Sophia-Antipolis, to
309output LLVM bytecode. It seems that it can already output .NET
310bytecode, JVM bytecode, and C, so LLVM would ostensibly be another good
311candidate.</li>
312<li>Write a new frontend for some other language (Java? OCaml? Forth?)</li>
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]313<li>Write a new backend for a target (IA64? MIPS? MMIX?)</li>
Misha Brukmandec8cfb2004-04-16 16:55:30 +0000[diff] [blame]314<li>Write a disassembler for machine code that would use TableGen to output
315<tt>MachineInstr</tt>s for transformations, optimizations, etc.</li>
Brian Gaekea2245a32004-03-10 19:15:50 +0000[diff] [blame]316<li>Random test vector generator: Use a C grammar to generate random C code;
317run it through llvm-gcc, then run a random set of passes on it using opt.
318Try to crash opt. When opt crashes, use bugpoint to reduce the test case and
319mail the result to yourself. Repeat ad infinitum.</li>
Misha Brukman1a49bc82004-03-10 19:22:29 +0000[diff] [blame]320<li>Design a simple, recognizable logo.</li>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]321</ol>
322
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]323</div>
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]324
325<!-- *********************************************************************** -->
Chris Lattnerb7131092003-02-06 19:39:21 +0000[diff] [blame]326
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]327<hr>
Misha Brukman836db502004-05-12 18:57:54 +0000[diff] [blame]328<address>
329 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
330 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
331 <a href="http://validator.w3.org/check/referer"><img
332 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
333
334 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
335 <a href="http://llvm.cs.uiuc.edu">LLVM Compiler Infrastructure</a><br>
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]336 Last modified: $Date$
Misha Brukman836db502004-05-12 18:57:54 +0000[diff] [blame]337</address>
Misha Brukman076438b2003-11-14 17:34:38 +0000[diff] [blame]338
339</body>
340</html>