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Galois Tech Talk: Towards a High-Assurance Runtime System: Certified Garbage Collection

Galois, Inc
421 SW 6th Ave. Suite 300
Portland, OR 97204, US (map)



Galois is pleased to host the following tech talk. These talks are open to the interested public. Please join us!


Towards a High-Assurance Runtime System: Certified Garbage Collection 


Andrew Tolmach 


10:30am, Tuesday, 29 June 2010.


Galois Inc.
421 SW 6th Ave. Suite 300, Portland, OR,
(3rd floor of the Commonwealth building) 


It seems obvious that the reliability of critical software can be improved by using high-level, memory-safe languages (Haskell, ML, Java, C#, etc.). But most existing implementations of these languages rely on large, complex run-time systems coded in C. Using such an RTS leads to a large "credibility gap" at the heart of the assurance argument for the overall system. To fill this gap, we are working to build a new high-assurance run-time system (HARTS), using an approach grounded in machine-assisted verification, with an initial focus on providing certifiably correct garbage collection.This talk will describe a machine-certified framework for correct compilation and execution of programs in garbage-collected languages. Our framework extends Leroy's Coq-certified Compcert compiler and Cminor intermediate language. We add a new intermediate language, GCminor, that supports GC'ed languages and has a proven semantics-preserving translation to assembly code. GCminor neatly encapsulates the interface between mutator and collector code, while remaining simple and flexible enough to be used with a wide variety of source languages and collector styles. Front ends targeting GCminor can be implemented using any compiler technology and any desired degree of verification, including full semantics preservation, type preservation, or informal trust. As an example application of our framework, we describe a compiler for Haskell that translates the GHC's Core intermediate language to GCminor. (This is joint work with Andrew McCreight and Tim Chevalier.)


Andrew Tolmach has been a faculty member at Portland State University since receiving his Ph.D.in Computer Science from Princeton in 1992. His current research interests, pursued under the aegis of the PSU High Assurance Systems Programming (HASP) project, focus on high-assurance systems software development, in particular using formal verification. His past publications, mostly about functional languages, include work on operating systems in Haskell, garbage collection, compilation, debugger implementation, integration with logic languages, and lazy functional algorithms.