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+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
+<html><head><title>Open LLVM Projects</title></head>
+
+<body bgcolor=white>
+<center><h1><font size=7>Open LLVM Projects</font></h1></center>
+
+<ul>
+ <li><a href="#what">What is this?</a>
+ <li><a href="#improving">Improving the current system</a>
+ <ol>
+ <li><a href="#glibc">Port glibc to LLVM</a>
+ <li><a href="#NightlyTest">Improving the Nightly Tester</a>
+ <li><a href="#programs">Compile programs with the LLVM Compiler</a>
+ <li><a href="#llvm_ir">Extend the LLVM intermediate representation</a>
+ <li><a href="#misc_imp">Miscellaneous Improvements</a>
+ </ol>
+
+ <li><a href="#new">Adding new capabilities to LLVM</a>
+ <ol>
+ <li><a href="#pointeranalysis">Pointer and Alias Analysis</a>
+ <li><a href="#profileguided">Profile Guided Optimization</a>
+ <li><a href="#xforms">New Transformations and Analyses</a>
+ <li><a href="#x86be">X86 Back-end Improvements</a>
+ <li><a href="#misc_new">Miscellaneous Additions</a>
+ </ol>
+</ul>
+
+<br><br>
+
+<!-- *********************************************************************** -->
+<table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
+<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
+<a name="what">What is this?
+</b></font></td></tr></table><ul>
+<!-- *********************************************************************** -->
+
+This document is meant to be a sort of "big TODO list" for LLVM. Each project
+in this document is something that would be useful for LLVM to have, and would
+also be a great way to get familiar with the system. Some of these projects are
+small and self-contained, which may be implemented in a couple of days, others
+are larger. Several of these projects may lead to interesting research projects
+in their own right. In any case, we welcome all contributions.<p>
+
+If you are thinking about tackling one of these projects, please send a mail to
+the <a href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM
+Developer's</a> mailing list, so that we know the project is being worked on.
+Additionally this is a good way to get more information about a specific project
+or to suggest other projects to add to this page.<p>
+
+
+<!-- *********************************************************************** -->
+</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
+<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
+<a name="improving">Improving the current system
+</b></font></td></tr></table><ul>
+<!-- *********************************************************************** -->
+
+Improvements to the current infrastructure are always very welcome and tend to
+be fairly straight-forward to implement. Here are some of the key areas that
+can use improvement...<p>
+
+<!-- ======================================================================= -->
+</ul><table width="50%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
+<tr><td> </td><td width=100%>
+<font color="#EEEEFF" size=+1 face="Georgia,Palatino"><b>
+<a name="glibc">Port glibc to LLVM
+</b></font></td></tr></table><ul>
+
+It would be very useful to <a
+href="http://www.gnu.org/software/libc/porting.html">port</a> <a
+href="http://www.gnu.org/software/glibc/">glibc</a> to LLVM. This would allow a
+variety of interprocedural algorithms to be much more effective in the face of
+library calls. The most important pieces to port are things like the string
+library and the <tt>stdio</tt> related functions... low-level system calls like
+'<tt>read</tt>' should stay unimplemented in LLVM.<p>
+
+
+<!-- ======================================================================= -->
+</ul><table width="50%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
+<tr><td> </td><td width=100%>
+<font color="#EEEEFF" size=+1 face="Georgia,Palatino"><b>
+<a name="NightlyTest">Improving the Nightly Tester
+</b></font></td></tr></table><ul>
+
+The <a href="/testresults/">Nightly Tester</a> is a simple perl script (located
+in utils/NightlyTest.pl) which runs every night to generate a daily report. It
+could use the following improvements:<p>
+
+<ol>
+<li>Olden timings - Time the compilation and execution times for the Olden
+ benchmark suite, keeping track of these values over time.
+
+<li>Graphs - It would be great to have gnuplot graphs to keep track of how the
+ tree is changing over time. We already gather a several statistics, it
+ just neccesary to add the script-fu to gnuplotize it.
+
+<li>Regression tests - We should run the regression tests in addition to the
+ program tests...
+</ol><p>
+
+<!-- ======================================================================= -->
+</ul><table width="50%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
+<tr><td> </td><td width=100%>
+<font color="#EEEEFF" size=+1 face="Georgia,Palatino"><b>
+<a name="programs">Compile programs with the LLVM Compiler
+</b></font></td></tr></table><ul>
+
+We are always looking for new testcases and benchmarks for use with LLVM. In
+particular, it is useful to try compiling your favorite C source code with LLVM.
+If it doesn't compile, try to figure out why or report it to the <a
+href="http://mail.cs.uiuc.edu/pipermail/llvmbugs/">llvm-bugs</a> list. If you
+get the program to compile, it would be extremely useful to convert the build
+system to be compatible with the LLVM Programs testsuite so that we can check it
+into CVS and the automated tester can use it to track progress of the compiler.
+
+
+<!-- ======================================================================= -->
+</ul><table width="50%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
+<tr><td> </td><td width=100%>
+<font color="#EEEEFF" size=+1 face="Georgia,Palatino"><b>
+<a name="llvm_ir">Extend the LLVM intermediate representation
+</b></font></td></tr></table><ul>
+
+<ol>
+<li>Transform <tt>setjmp</tt> and <tt>longjmp</tt> calls to use the LLVM
+ <tt>invoke</tt> mechanism.
+<li>Add support for a volatile attribute on loads and stores
+<li>Support for variable argument functions
+<li>Add a new conditional move instruction: <tt>X = select bool Cond, Y, Z</tt>
+<li>Add support for platform independant prefetch support. The GCC <a
+ href="http://gcc.gnu.org/projects/prefetch.html">prefetch project</a> page
+ has a good survey of the prefetching capabilities of a variety of modern
+ processors.
+</ol>
+
+
+<!-- ======================================================================= -->
+</ul><table width="50%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
+<tr><td> </td><td width=100%>
+<font color="#EEEEFF" size=+1 face="Georgia,Palatino"><b>
+<a name="misc_imp">Miscellaneous Improvements
+</b></font></td></tr></table><ul>
+
+<ol>
+<li>Improve the efficiency of the bytecode loader/writer, allow streaming lazy
+ loading of functions from the bytecode (for use by the JIT, for example)<br>
+<li>Rework the PassManager
+<li>Do not encode zero intializers for large arrays into the bytecode
+
+<li>Some transformations and analyses only work on reducible flow graphs. It
+would be nice to have a transformation which could be "required" by these passes
+which makes irreducible graphs reducible. This can easily be accomplished
+through code duplication. See <a
+href="http://citeseer.nj.nec.com/janssen97making.html">Making Graphs Reducible
+with Controlled Node Splitting</a> and perhaps <a
+href="http://doi.acm.org/10.1145/262004.262005">Nesting of Reducible and
+Irreducible Loops</a>.
+</ol>
+
+
+<!-- *********************************************************************** -->
+</ul><table width="100%" bgcolor="#330077" border=0 cellpadding=4 cellspacing=0>
+<tr><td align=center><font color="#EEEEFF" size=+2 face="Georgia,Palatino"><b>
+<a name="new">Adding new capabilities to LLVM
+</b></font></td></tr></table><ul>
+<!-- *********************************************************************** -->
+
+Sometimes creating new things is more fun that improving existing things. These
+projects tend to be more involved and perhaps require more work, but can also be
+very rewarding.<p>
+
+<!-- ======================================================================= -->
+</ul><table width="50%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
+<tr><td> </td><td width=100%>
+<font color="#EEEEFF" size=+1 face="Georgia,Palatino"><b>
+<a name="pointeranalysis">Pointer and Alias Analysis
+</b></font></td></tr></table><ul>
+
+We have a strong base for development of both pointer analysis based
+optimizations as well as pointer analyses themselves. It seems natural to want
+to take advantage of this...<p>
+
+<ol>
+<li>Implement a flow-sensitive context-sensitive alias analysis algorithm<br>
+ - Pick one of the somewhat efficient algorithms, but strive for maximum
+ precision
+<li>Implement a flow-sensitive context-insensitive alias anlaysis algorithm<br>
+ - Just an efficient local algorithm perhaps?
+
+<li>Implement an interface to update analyses in response to common code motion
+ transformations
+<li>Implement alias analysis based optimizations:
+ <ul>
+ <li>Dead store elimination
+ <li>Location invariant Code Motion (LcICM)
+ <li>Store+Reload or "store forwarding" elimination:<p>
+ Change:
+ <pre>
+ store int X, int* P
+ Y = load int* P</pre>
+ into:
+ <pre>
+ store int X, int *P
+ Y = X</pre>
+ <li>Register promotion (move loads and stores out of loop bodies, for example)
+ </ul>
+</ol>
+
+<!-- ======================================================================= -->
+</ul><table width="50%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
+<tr><td> </td><td width=100%>
+<font color="#EEEEFF" size=+1 face="Georgia,Palatino"><b>
+<a name="profileguided">Profile Guided Optimization
+</b></font></td></tr></table><ul>
+
+We are getting to the point where we really need a unified infrastructure for
+profile guided optimizations. It would be wonderful to be able to write profile
+guided transformations which can be performed either at static compile time
+(compile time or offline optimization time) or at runtime in a JIT type setup.
+The LLVM transformation itself shouldn't need to know how it is being used.<p>
+
+Ideas for profile guided transformations:<p>
+
+<ol>
+<li>Superblock formation (with many optimizations)
+<li>Loop unrolling/peeling
+<li>Profile directed inlining
+<li>Code layout
+<li>...
+</ol><p>
+
+
+<!-- ======================================================================= -->
+</ul><table width="50%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
+<tr><td> </td><td width=100%>
+<font color="#EEEEFF" size=+1 face="Georgia,Palatino"><b>
+<a name="xforms">New Transformations and Analyses
+</b></font></td></tr></table><ul>
+
+<ol>
+<li>Implement a Dependence Analysis Infrastructure<br>
+ - Design some way to represent and query dep analysis
+<li>Implement a faster Dominator Set Construction Algorithm<br>
+ - A linear time or nearly so algorithm
+<li>Implement a strength reduction pass
+<li>Value range propagation pass
+<li>Implement a tail recursion elimination pass
+<li>Implement an unswitching pass
+</ol>
+
+<!-- ======================================================================= -->
+</ul><table width="50%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
+<tr><td> </td><td width=100%>
+<font color="#EEEEFF" size=+1 face="Georgia,Palatino"><b>
+<a name="x86be">X86 Back-end Improvements
+</b></font></td></tr></table><ul>
+
+<ol>
+<li>Implement a global register allocator
+<li>Implement a better instruction selector
+<li>Implement a static compiler in addition to the JIT (easy project)
+</ol>
+
+<!-- ======================================================================= -->
+</ul><table width="50%" bgcolor="#441188" border=0 cellpadding=4 cellspacing=0>
+<tr><td> </td><td width=100%>
+<font color="#EEEEFF" size=+1 face="Georgia,Palatino"><b>
+<a name="misc_new">Miscellaneous Additions
+</b></font></td></tr></table><ul>
+
+<ol>
+<li>Write a new frontend for some language (Java? OCaml? Forth?)
+<li>Write a new backend for a target (IA64? MIPS? MMIX?)
+</ol>
+
+
+<!-- *********************************************************************** -->
+</ul>
+<!-- *********************************************************************** -->
+
+<hr><font size-1>
+<address><a href="mailto:sabre@nondot.org">Chris Lattner</a></address>
+<!-- Created: Tue Aug 6 15:00:33 CDT 2002 -->
+<!-- hhmts start -->
+Last modified: Thu Feb 6 13:38:41 CST 2003
+<!-- hhmts end -->
+</font></body></html>