2003-02-06 19:39:21 +00:00
|
|
|
<!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
|
2003-10-25 18:41:16 +00:00
|
|
|
or to suggest other projects to add to this page. Another good place to
|
|
|
|
|
look for ideas is the
|
|
|
|
|
<a href="http://llvm.cs.uiuc.edu/bugs/">LLVM bug tracker</a>.<p>
|
2003-02-06 19:39:21 +00:00
|
|
|
|
|
|
|
|
|
|
|
|
|
<!-- *********************************************************************** -->
|
|
|
|
|
</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
|
2003-08-18 14:43:39 +00:00
|
|
|
just necessary to add the script-fu to gnuplotize it.
|
2003-02-06 19:39:21 +00:00
|
|
|
|
|
|
|
|
<li>Regression tests - We should run the regression tests in addition to the
|
|
|
|
|
program tests...
|
|
|
|
|
</ol><p>
|
|
|
|
|
|
2003-02-07 19:25:35 +00:00
|
|
|
|
2003-02-06 19:39:21 +00:00
|
|
|
<!-- ======================================================================= -->
|
|
|
|
|
</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
|
2003-02-07 19:25:35 +00:00
|
|
|
into CVS and the automated tester can use it to track progress of the
|
|
|
|
|
compiler.<p>
|
|
|
|
|
|
|
|
|
|
When testing a code, try running it with a variety of optimizations, and with
|
|
|
|
|
all the back-ends: CBE, llc, and lli.<p>
|
2003-02-06 19:39:21 +00:00
|
|
|
|
|
|
|
|
|
|
|
|
|
<!-- ======================================================================= -->
|
|
|
|
|
</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>Add a new conditional move instruction: <tt>X = select bool Cond, Y, Z</tt>
|
2003-03-08 23:59:05 +00:00
|
|
|
<li>Add support for platform independent prefetch support. The GCC <a
|
2003-02-06 19:39:21 +00:00
|
|
|
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>
|
2003-05-06 20:47:11 +00:00
|
|
|
<li>Someone needs to look into getting the <tt>ranlib</tt> tool to index LLVM
|
|
|
|
|
bytecode files, so that linking in .a files is not hideously slow. They
|
|
|
|
|
would also then have to implement the reader for this index in
|
|
|
|
|
<tt>gccld</tt>.<br>
|
|
|
|
|
|
2003-10-01 21:49:55 +00:00
|
|
|
<li>Improve the efficiency of the bytecode loader/writer<br>
|
|
|
|
|
<li>Extend the FunctionPassManager to use a ModuleProvider to stream functions
|
|
|
|
|
in on demand. This would improve the efficiency of the JIT.
|
2003-04-28 03:42:31 +00:00
|
|
|
<li>Rework the PassManager to be more flexible
|
2003-02-06 19:39:21 +00:00
|
|
|
<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>
|
|
|
|
|
|
2003-07-25 18:05:38 +00:00
|
|
|
We have a <a href="AliasAnalysis.html">strong base for development</a> of both
|
|
|
|
|
pointer analysis based optimizations as well as pointer analyses themselves. It
|
|
|
|
|
seems natural to want to take advantage of this...<p>
|
2003-02-06 19:39:21 +00:00
|
|
|
|
|
|
|
|
<ol>
|
|
|
|
|
<li>Implement a flow-sensitive context-sensitive alias analysis algorithm<br>
|
|
|
|
|
- Pick one of the somewhat efficient algorithms, but strive for maximum
|
|
|
|
|
precision
|
2003-06-25 14:31:06 +00:00
|
|
|
<li>Implement a flow-sensitive context-insensitive alias analysis algorithm<br>
|
2003-02-06 19:39:21 +00:00
|
|
|
- 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
|
|
|
|
|
</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 an unswitching pass
|
2003-08-06 15:40:37 +00:00
|
|
|
<li>Write a loop unroller, with a simple heuristic for when to unroll
|
2003-02-06 19:39:21 +00:00
|
|
|
</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
|
2003-04-28 03:42:31 +00:00
|
|
|
<li>Implement support for the "switch" instruction without requiring the
|
|
|
|
|
lower-switches pass.
|
2003-02-06 19:39:21 +00:00
|
|
|
</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>
|
2003-10-27 18:18:16 +00:00
|
|
|
<a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a>
|
|
|
|
|
<br>
|
2003-02-06 19:39:21 +00:00
|
|
|
<!-- Created: Tue Aug 6 15:00:33 CDT 2002 -->
|
|
|
|
|
<!-- hhmts start -->
|
2003-10-27 18:18:16 +00:00
|
|
|
Last modified: Mon Oct 27 12:00:00 CDT 2003
|
2003-02-06 19:39:21 +00:00
|
|
|
<!-- hhmts end -->
|
|
|
|
|
</font></body></html>
|
