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Full-Text Articles in Physical Sciences and Mathematics
Exterminator: Automatically Correcting Memory Errors With High Probability, Gene Novark
Exterminator: Automatically Correcting Memory Errors With High Probability, Gene Novark
Computer Science Department Faculty Publication Series
Programs written in C and C++ are susceptible to memory errors, including buffer overflows and dangling pointers. These errors, which can lead to crashes, erroneous execution, and security vulnerabilities, are notoriously costly to repair. Tracking down their location in the source code is difficult, even when the full memory state of the program is available. Once the errors are finally found, fixing them remains challenging: even for critical security-sensitive bugs, the average time between initial reports and the issuance of a patch is nearly one month. We present Exterminator, a system that automatically corrects heap-based memory errors without programmer intervention. …
Incremental Test Collections, Ben Carterette, James Allan
Incremental Test Collections, Ben Carterette, James Allan
Computer Science Department Faculty Publication Series
Corpora and topics are readily available for information retrieval research. Relevance judgments, which are necessary for system evaluation, are expensive; the cost of obtaining them prohibits in-house evaluation of retrieval systems on new corpora or new topics. We present an algorithm for cheaply constructing sets of relevance judgments. Our method intelligently selects documents to be judged and decides when to stop in such a way that with very little work there can be a high degree of confidence in the result of the evaluation. We demonstrate the algorithm's effectiveness by showing that it produces small sets of relevance judgments that …
Using Types To Analyze And Optimize Object-Oriented Programs, Amer Diwan, Kathryn S. Mckinley, J. Eliot B. Moss
Using Types To Analyze And Optimize Object-Oriented Programs, Amer Diwan, Kathryn S. Mckinley, J. Eliot B. Moss
Computer Science Department Faculty Publication Series
Object-oriented programming languages provide many software engineering benefits, but these often come at a performance cost. Object-oriented programs make extensive use of method in- vocations and pointer dereferences, both of which are potentially costly on modern machines. We show how to use types to produce effective, yet simple, techniques that reduce the costs of these features in Modula-3, a statically typed, object-oriented language. Our compiler performs type-based alias analysis to disambiguate memory references. It uses the results of the type-based alias analysis to eliminate redundant memory references and to replace monomorphic method in- vocation sites with direct calls. Using limit, …