Finding and preventing run-time error handling mistakes

13 years 10 months ago

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It is diﬃcult to write programs that behave correctly in the presence of run-time errors. Existing programming language features often provide poor support for executing clean-up code and for restoring invariants in such exceptional situations. We present a dataﬂow analysis for ﬁnding a certain class of error-handling mistakes: those that arise from a failure to release resources or to clean up properly along all paths. Many real-world programs violate such resource safety policies because of incorrect error handling. Our ﬂow-sensitive analysis keeps track of outstanding obligations along program paths and does a precise modeling of control ﬂow in the presence of exceptions. Using it, we have found over 800 error handling mistakes almost 4 million lines of Java code. The analysis is unsound and produces false positives, but a few simple ﬁltering rules suﬃce to remove them in practice. The remaining mistakes were manually veriﬁed. These mistakes cause sockets, ﬁles an...

Westley Weimer, George C. Necula

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