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Google Summer of Code (2013)
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== Mentors ==

The following developers have agreed to serve as mentors for the 2013 Google Summer of Code:

* http://www.cs.rit.edu/%7Emtf[Matthew Fluet]
* http://www.cse.buffalo.edu/%7Elziarek/[Lukasz (Luke) Ziarek]
* http://www.cs.purdue.edu/homes/suresh/[Suresh Jagannathan]

== Ideas List ==

=== Implement a Partial Redundancy Elimination (PRE) Optimization ===

Partial redundancy elimination (PRE) is a program transformation that
removes operations that are redundant on some, but not necessarily all
paths, through the program.  PRE can subsume both common subexpression
elimination and loop-invariant code motion, and is therefore a
potentially powerful optimization.  However, a naïve
implementation of PRE on a program in static single assignment (SSA)
form is unlikely to be effective.  This project aims to adapt and
implement the SSAPRE algorithm(s) of Thomas VanDrunen in MLton's SSA
intermediate language.

Background:
--
* http://onlinelibrary.wiley.com/doi/10.1002/spe.618/abstract[Anticipation-based partial redundancy elimination for static single assignment form]; Thomas VanDrunen and Antony L. Hosking
* http://cs.wheaton.edu/%7Etvandrun/writings/thesis.pdf[Partial Redundancy Elimination for Global Value Numbering]; Thomas VanDrunen
* http://www.springerlink.com/content/w06m3cw453nphm1u/[Value-Based Partial Redundancy Elimination]; Thomas VanDrunen and Antony L. Hosking
* http://portal.acm.org/citation.cfm?doid=319301.319348[Partial redundancy elimination in SSA form]; Robert Kennedy, Sun Chan, Shin-Ming Liu, Raymond Lo, Peng Tu, and Fred Chow
--

Recommended Skills: SML programming experience; some middle-end compiler experience

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Mentor: http://www.cs.rit.edu/%7Emtf[Matthew Fluet]
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=== Design and Implement a Heap Profiler ===

A heap profile is a description of the space usage of a program.  A
heap profile is concerned with the allocation, retention, and
deallocation (via garbage collection) of heap data during the
execution of a program.  A heap profile can be used to diagnose
performance problems in a functional program that arise from space
leaks.  This project aims to design and implement a heap profiler for
MLton compiled programs.

Background:
--
* http://portal.acm.org/citation.cfm?doid=583854.582451[GCspy: an adaptable heap visualisation framework]; Tony Printezis and Richard Jones
* http://journals.cambridge.org/action/displayAbstract?aid=1349892[New dimensions in heap profiling]; Colin Runciman and Niklas Röjemo
* http://www.springerlink.com/content/710501660722gw37/[Heap profiling for space efficiency]; Colin Runciman and Niklas Röjemo
* http://journals.cambridge.org/action/displayAbstract?aid=1323096[Heap profiling of lazy functional programs]; Colin Runciman and David Wakeling
--

Recommended Skills: C and SML programming experience; some experience with UI and visualization

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Mentor: http://www.cs.rit.edu/%7Emtf[Matthew Fluet]
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=== Garbage Collector Improvements ===

The garbage collector plays a significant role in the performance of
functional languages.  Garbage collect too often, and program
performance suffers due to the excessive time spent in the garbage
collector.  Garbage collect not often enough, and program performance
suffers due to the excessive space used by the uncollected garbage.
One particular issue is ensuring that a program utilizing a garbage
collector "plays nice" with other processes on the system, by not
using too much or too little physical memory.  While there are some
reasonable theoretical results about garbage collections with heaps of
fixed size, there seems to be insufficient work that really looks
carefully at the question of dynamically resizing the heap in response
to the live data demands of the application and, similarly, in
response to the behavior of the operating system and other processes.
This project aims to investigate improvements to the memory behavior of
MLton compiled programs through better tuning of the garbage
collector.

Background:
--
* http://www.dcs.gla.ac.uk/%7Ewhited/papers/automated_heap_sizing.pdf[Automated Heap Sizing in the Poly/ML Runtime (Position Paper)]; David White, Jeremy Singer, Jonathan Aitken, and David Matthews
* http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4145125[Isla Vista Heap Sizing: Using Feedback to Avoid Paging]; Chris Grzegorczyk, Sunil Soman, Chandra Krintz, and Rich Wolski
* http://portal.acm.org/citation.cfm?doid=1152649.1152652[Controlling garbage collection and heap growth to reduce the execution time of Java applications]; Tim Brecht, Eshrat Arjomandi, Chang Li, and Hang Pham
* http://portal.acm.org/citation.cfm?doid=1065010.1065028[Garbage collection without paging]; Matthew Hertz, Yi Feng, and Emery D. Berger
* http://portal.acm.org/citation.cfm?doid=1029873.1029881[Automatic heap sizing: taking real memory into account]; Ting Yang, Matthew Hertz, Emery D. Berger, Scott F. Kaplan, and J. Eliot B. Moss
--

Recommended Skills: C programming experience; some operating systems and/or systems programming experience; some compiler and garbage collector experience

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Mentor: http://www.cs.rit.edu/%7Emtf[Matthew Fluet]
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=== Implement Successor{nbsp}ML Language Features ===

Any programming language, including Standard{nbsp}ML, can be improved.
The community has identified a number of modest extensions and
revisions to the Standard{nbsp}ML programming language that would
likely prove useful in practice.  This project aims to implement these
language features in the MLton compiler.

Background:
--
* http://successor-ml.org/index.php?title=Main_Page[Successor{nbsp}ML]
* http://www.mpi-sws.org/%7Erossberg/hamlet/index.html#successor-ml[HaMLet (Successor{nbsp}ML)]
* http://journals.cambridge.org/action/displayAbstract?aid=1322628[A critique of Standard{nbsp}ML]; Andrew W. Appel
--

Recommended Skills: SML programming experience; some front-end compiler experience (i.e., scanners and parsers)

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Mentor: http://www.cs.rit.edu/%7Emtf[Matthew Fluet]
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=== Implement Source-level Debugging ===

Debugging is a fact of programming life.  Unfortunately, most SML
implementations (including MLton) provide little to no source-level
debugging support.  This project aims to add basic to intermediate
source-level debugging support to the MLton compiler.  MLton already
supports source-level profiling, which can be used to attribute bytes
allocated or time spent in source functions.  It should be relatively
straightforward to leverage this source-level information into basic
source-level debugging support, with the ability to set/unset
breakpoints and step through declarations and functions.  It may be
possible to also provide intermediate source-level debugging support,
with the ability to inspect in-scope variables of basic types (e.g.,
types compatible with MLton's foreign function interface).

Background:
--
* http://mlton.org/HowProfilingWorks[MLton -- How Profiling Works]
* http://mlton.org/ForeignFunctionInterfaceTypes[MLton -- Foreign Function Interface Types]
* http://dwarfstd.org/[DWARF Debugging Standard]
* http://sourceware.org/gdb/current/onlinedocs/stabs/index.html[STABS Debugging Format]
--

Recommended Skills: SML programming experience; some compiler experience

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Mentor: http://www.cs.rit.edu/%7Emtf[Matthew Fluet]
/////

=== SIMD Primitives ===

Most modern processors offer some direct support for SIMD (Single
Instruction, Multiple Data) operations, such as Intel's MMX/SSE
instructions, AMD's 3DNow!  instructions, and IBM's AltiVec.  Such
instructions are particularly useful for multimedia, scientific, and
cryptographic applications.  This project aims to add preliminary
support for vector data and vector operations to the MLton compiler.
Ideally, after surveying SIMD instruction sets and SIMD support in
other compilers, a core set of SIMD primitives with broad architecture
and compiler support can be identified.  After adding SIMD primitives
to the core compiler and carrying them through to the various
backends, there will be opportunities to design and implement an SML
library that exposes the primitives to the SML programmer as well as
opportunities to design and implement auto-vectorization
optimizations.

Background:
--
* http://en.wikipedia.org/wiki/SIMD[SIMD]
* http://gcc.gnu.org/projects/tree-ssa/vectorization.html[Auto-vectorization in GCC]
* http://llvm.org/docs/Vectorizers.html[Auto-vectorization in LLVM]
--

Recommended Skills: SML programming experience; some compiler experience; some computer architecture experience

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Mentor: http://www.cs.rit.edu/%7Emtf[Matthew Fluet]
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=== RTOS Support ===

This project entails porting the MLton compiler to RTOSs such as:
RTEMS, RT Linux, and FreeRTOS.  The project will include modifications
to the MLton build and configuration process.  Students will need to
extend the MLton configuration process for each of the RTOSs.  The
MLton compilation process will need to be extended to invoke the C
cross compilers the RTOSs provide for embedded support.  Test scripts
for validation will be necessary and these will need to be run in
emulators for supported architectures.

Recommended Skills: C programming experience; some scripting experience

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Mentor: http://www.cse.buffalo.edu/%7Elziarek/[Lukasz (Luke) Ziarek]
/////

=== Region Based Memory Management ===

Region based memory management is an alternative automatic memory
management scheme to garbage collection.  Regions can be inferred by
the compiler (e.g., Cyclone and MLKit) or provided to the programmer
through a library.  Since many students do not have extensive
experience with compilers we plan on adopting the later approach.
Creating a viable region based memory solution requires the removal of
the GC and changes to the allocator.  Additionally, write barriers
will be necessary to ensure references between two ML objects is never
established if the left hand side of the assignment has a longer
lifetime than the right hand side.  Students will need to come up with
an appropriate interface for creating, entering, and exiting regions
(examples include RTSJ scoped memory and SCJ scoped memory).

Background:
--
* Cyclone
* MLKit
* RTSJ + SCJ scopes
--

Recommended Skills: SML programming experience; C programming experience; some compiler and garbage collector experience

/////
Mentor: http://www.cse.buffalo.edu/%7Elziarek/[Lukasz (Luke) Ziarek]
/////

=== Integration of Multi-MLton ===

http://multimlton.cs.purdue.edu[MultiMLton] is a compiler and runtime
environment that targets scalable multicore platforms.  It is an
extension of MLton.  It combines new language abstractions and
associated compiler analyses for expressing and implementing various
kinds of fine-grained parallelism (safe futures, speculation,
transactions, etc.), along with a sophisticated runtime system tuned
to efficiently handle large numbers of lightweight threads.  The core
stable features of MultiMLton will need to be integrated with the
latest MLton public release.  Certain experimental features, such as
support for the Intel SCC and distributed runtime will be omitted.
This project requires students to understand the delta between the
MultiMLton code base and the MLton code base.  Students will need to
create build and configuration scripts for MLton to enable MultiMLton
features.

Background
--
* http://multimlton.cs.purdue.edu/mML/Publications.html[MultiMLton -- Publications]
--

Recommended Skills: SML programming experience; C programming experience; some compiler experience

/////
Mentor: http://www.cse.buffalo.edu/%7Elziarek/[Lukasz (Luke) Ziarek]
/////