points_to_linear_slides

points_to_linear_slides - Points-to Analysis in Almost...

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Points-to Analysis in Almost Linear Time Bjarne Steensgard
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Constraint-based Analysis Idea: generate constraints and solve them later x = &a; y = &b; p = &x; p = &y; x a p y b
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Inclusion-based Analysis x = y pointsTo(x) ≥ pointsTo(y) What is the major drawback of this approach? O(n 3 )
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How can we do this faster? Use equality-based analysis. Why?
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Equality-based Analysis x = y pointsTo(x) = pointsTo(y) Why is this faster? What are the tradeoffs?
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What should x point to? x = a x = b a x b a x b
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Imprecise, but fast – really? How to do equality-based, flow-insensitive analysis in one pass? Use type inference with points-to sets as types For every variable X, let X’s type α x = pointsTo(X) The set {α x } – the goal of the analysis – is found using unification-based type inference How is this analysis equality-based?
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Type system for points-to inference 3 kinds of types: Value types – (pointer, function) tuples α ::= τ × λ pointer/address types:
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This note was uploaded on 02/24/2012 for the course CSE 503 taught by Professor Davidnotikin during the Winter '11 term at University of Washington.

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points_to_linear_slides - Points-to Analysis in Almost...

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