diff --git a/docs/OpenProjects.html b/docs/OpenProjects.html deleted file mode 100644 index bc574e53434..00000000000 --- a/docs/OpenProjects.html +++ /dev/null @@ -1,394 +0,0 @@ - - - - Open LLVM Projects - - - - -
- Open LLVM Projects -
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Written by the LLVM Team

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- What is this? -
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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.

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If you are thinking about tackling one of these projects, please send a mail -to the LLVM -Developer's 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. -

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The projects in this page are open-ended. More specific projects are -filed as unassigned enhancements in the -LLVM bug tracker. See the list of currently outstanding issues if you wish to help improve LLVM.

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- Improving the current system -
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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...

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- Implementing Code Cleanup bugs -
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-The LLVM bug tracker occasionally -has "code-cleanup" bugs filed in it. Taking one of these and fixing it is a good -way to get your feet wet in the LLVM code and discover how some of its components -work. -

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- Port glibc to LLVM -
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It would be very useful to port glibc 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 stdio related functions... low-level system calls like -'read' should stay unimplemented in LLVM.

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- Compile programs with the LLVM Compiler -
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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 llvm-bugs 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.

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When testing a code, try running it with a variety of optimizations, and with -all the back-ends: CBE, llc, and lli.

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- Extend the LLVM intermediate representation -
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  1. Add support for platform-independent prefetch support. The GCC prefetch project page - has a good survey of the prefetching capabilities of a variety of modern - processors.
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- Target backend improvements -
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  1. Find benchmarks either using our test results or on your own, - where LLVM code generators do not produce optimal code or simply where another - compiler produces better code. Try to minimize the test case that - demonstrates the issue. Then, either submit a bug with your testcase and - the code that LLVM produces vs. the code that it should produce, or - even better, see if you can improve the code generator and submit a - patch.
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- Miscellaneous Improvements -
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  1. Rework the PassManager to be more flexible
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  2. 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 Making Graphs Reducible -with Controlled Node Splitting and perhaps Nesting of Reducible and -Irreducible Loops.
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- Adding new capabilities to LLVM -
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Sometimes creating new things is more fun than improving existing things. -These projects tend to be more involved and perhaps require more work, but can -also be very rewarding.

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- Implementing new feature PRs -
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Many ideas for feature requests are stored in LLVM bugzilla. Just search for bugs with a "new-feature" keyword.

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- Pointer and Alias Analysis -
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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...

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  1. Implement a flow-sensitive context-sensitive alias analysis algorithm
    - - Pick one of the somewhat efficient algorithms, but strive for maximum - precision
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  2. Implement a flow-sensitive context-insensitive alias analysis algorithm
    - - Just an efficient local algorithm perhaps?
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  3. Implement alias-analysis-based optimizations: -
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    • ...
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- Profile-Guided Optimization -
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We now have a unified infrastructure for writing profile-guided -transformations, which will work either at offline-compile-time or in the JIT, -but we don't have many transformations. We would welcome new profile-guided -transformations as well as improvements to the current profiling system. -

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Ideas for profile-guided transformations:

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  1. Superblock formation (with many optimizations)
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  2. Loop unrolling/peeling
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  3. Profile directed inlining
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  4. Code layout
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  5. ...
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Improvements to the existing support:

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  1. The current block and edge profiling code that gets inserted is very simple -and inefficient. Through the use of control-dependence information, many fewer -counters could be inserted into the code. Also, if the execution count of a -loop is known to be a compile-time or runtime constant, all of the counters in -the loop could be avoided.
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  2. You could implement one of the "static profiling" algorithms which analyze a -piece of code an make educated guesses about the relative execution frequencies -of various parts of the code.
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  3. You could add path profiling support, or adapt the existing LLVM path -profiling code to work with the generic profiling interfaces.
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- New Transformations and Analyses -
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  1. Implement GVN-PRE, a - powerful and simple Partial Redundancy Elimination algorithm for SSA form
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  2. Implement a Dependence Analysis Infrastructure
    - - Design some way to represent and query dep analysis
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  3. Implement a strength reduction pass
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  4. Value range propagation pass
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- X86 Back-end Improvements -
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  1. Implement a better instruction selector
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  2. Implement support for the "switch" instruction without requiring the - lower-switches pass.
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  3. Implement interprocedural register allocation. The CallGraphSCCPass can be - used to implement a bottom-up analysis that will determine the *actual* - registers clobbered by a function. Use the pass to fine tune register usage - in callers based on *actual* registers used by the callee.
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- Miscellaneous Additions -
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  1. Port the Bigloo -Scheme compiler, from Manuel Serrano at INRIA Sophia-Antipolis, to -output LLVM bytecode. It seems that it can already output .NET -bytecode, JVM bytecode, and C, so LLVM would ostensibly be another good -candidate.
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  2. Write a new frontend for C/C++ in C++, giving us the ability to -directly use LLVM C++ classes from within a compiler rather than use -C-based wrapper functions a la llvm-gcc. One possible starting point is the C++ -yacc grammar by Ed Willink.
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  3. Write a new frontend for some other language (Java? OCaml? Forth?)
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  4. Write a new backend for a target (IA64? MIPS? MMIX?)
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  5. Write a disassembler for machine code that would use TableGen to output -MachineInstrs for transformations, optimizations, etc.
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  6. Random test vector generator: Use a C grammar to generate random C code; -run it through llvm-gcc, then run a random set of passes on it using opt. -Try to crash opt. When opt crashes, use bugpoint to reduce the test case and -mail the result to yourself. Repeat ad infinitum.
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  7. Design a simple, recognizable logo.
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  8. Improve the usefulness and utility of the Skeleton target backend: -
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    • Convert the non-functional Skeleton target to become an abstract machine - target (choose some simple instructions, a register set, etc). This will - become a much more useful example of a backend since it would be a simple - but functional backend. Examples of such architectures include MIX, - MMIX, DLX, - or come up with your own!
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    • Use the new Skeleton backend in the Interpreter: compile LLVM to Skeleton - target, and then interpret that code instead of LLVM. Performance win would - be the primary goal, as the number of registers would be a small constant - instead of unbounded, for example.
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- Valid CSS! - Valid HTML 4.01! - - Chris Lattner
- LLVM Compiler Infrastructure
- Last modified: $Date$ -
- - - diff --git a/docs/index.html b/docs/index.html index e0eb24e8c3f..d17901c6ffe 100644 --- a/docs/index.html +++ b/docs/index.html @@ -128,10 +128,6 @@ Provides information on using the command line parsing library. Details the LLVM coding standards and provides useful information on writing efficient C++ code. -
  • Open Projects - Look here if you are -interested in doing something with LLVM but aren't sure what needs to be -done.
    • -
  • Extending LLVM - Look here to see how to add instructions and intrinsics to LLVM.