Efficiently solving the “use-def” problem involving label variables

摘要

A method for efficiently solving the “use-def” problem involving label variables performs a data-flow analysis on a control flow graph that includes calculating an inset for each node as follows: if a predecessor node directly branches to the node, the method includes an outset of the predecessor node in the inset of the node; if a predecessor node indirectly branches to the node via a label variable and the node is in definitions of the label variable in the outset of the predecessor node, the method includes the outset of the predecessor node in the inset of the node; if a predecessor node indirectly branches to the node via a label variable and the node is not in definitions of the label variable in the outset of the predecessor node, the method does not include the outset of the predecessor node in the inset of the node.